ISP HOLDINGS INC
S-4/A, 1997-02-13
PLASTIC MATERIALS, SYNTH RESINS & NONVULCAN ELASTOMERS
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<PAGE>
   
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON FEBRUARY 13, 1997
    
 
   
                                                      REGISTRATION NO. 333-17827
    
=============================================================================== 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                            ------------------------
 
   
                                AMENDMENT NO. 1
                                       TO
    
                                    FORM S-4
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
 
                            ------------------------
                               ISP HOLDINGS INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
<TABLE>
<S>                                       <C>                                       <C>
                DELAWARE                                    6719                                   51-0376469
    (STATE OR OTHER JURISDICTION OF             (PRIMARY STANDARD INDUSTRIAL                    (I.R.S. EMPLOYER
     INCORPORATION OR ORGANIZATION)             CLASSIFICATION CODE NUMBER)                  IDENTIFICATION NUMBER)
</TABLE>
 
                            ------------------------
 
                               ISP HOLDINGS INC.
                             818 WASHINGTON STREET
                           WILMINGTON, DELAWARE 19801
                                 (302) 428-0847
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                  OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
                            ------------------------
 
                           RICHARD A. WEINBERG, ESQ.
                          ISP MANAGEMENT COMPANY, INC.
                                 1361 ALPS ROAD
                            WAYNE, NEW JERSEY 07470
                                 (201) 628-3000
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
 
                            ------------------------
 

                                With a copy to:
                            STEPHEN E. JACOBS, ESQ.
                           WEIL, GOTSHAL & MANGES LLP
                                767 FIFTH AVENUE
                         NEW YORK, NEW YORK 10153-0119
                                 (212) 310-8000
 
                            ------------------------
 
     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this Registration Statement.
 
     If any of the securities being registered on this Form are to be offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box. / /

                            ------------------------
 
   
     THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
    
 
=============================================================================== 

<PAGE>

A registration statement relating to these securities has been filed with the
Securities and Exchange Commission but has not yet become effective.  
Information contained herein is subject to completion or amendment. These
securities may not be sold nor may offers to buy be accepted prior to the time
the registration statement becomes effective.  This prospectus shall not
constitute an offer to sell or the solicitation of an offer to buy nor shall
there be any sale of these securities in any State in which such offer,
solicitation or sale would be unlawful prior to registration or qualification
under the securities laws of any such State.

   
                 SUBJECT TO COMPLETION, DATED FEBRUARY 13, 1997
    
PROSPECTUS
                                   OFFER FOR
 
                    ALL OUTSTANDING 9% SENIOR NOTES DUE 2003
               IN EXCHANGE FOR SERIES B 9% SENIOR NOTES DUE 2003
                                      AND
                  ALL OUTSTANDING 9 3/4% SENIOR NOTES DUE 2002
             IN EXCHANGE FOR SERIES B 9 3/4% SENIOR NOTES DUE 2002
                                       OF

                               ISP HOLDINGS INC.
 
          EACH OF THESE EXCHANGE OFFERS WILL EXPIRE AT 12:00 MIDNIGHT,
                 NEW YORK CITY TIME, ON                , 1997.
                            ------------------------
 
     ISP Holdings Inc., a Delaware corporation ('ISP Holdings'), hereby offers,
upon the terms and subject to the conditions set forth in this Prospectus and
the accompanying Letter of Transmittal (each of which constitutes an 'Exchange
Offer' and both of which together constitute the 'Exchange Offers'), to exchange
(i) $1,000 principal amount of its Series B 9% Senior Notes due 2003 (the 'New
9% Notes') for each $1,000 principal amount of its 9% Senior Notes due 2003 (the
'Old 9% Notes'), of which an aggregate principal amount of $325,000,000 is
outstanding, and (ii) $1,000 principal amount of its Series B 9 3/4% Senior
Notes due 2002 (the 'New 9 3/4% Notes') for each $1,000 principal amount of its
9 3/4% Senior Notes due 2002 (the 'Old 9 3/4% Notes'), of which an aggregate
principal amount of $199,871,000 is outstanding.
 
     The form and terms of the New 9% Notes are identical to the form and terms
of the Old 9% Notes except that the New 9% Notes have been registered under the
Securities Act of 1933, as amended (the 'Securities Act'), and will not bear any
legends restricting the transfer thereof. The New 9% Notes will evidence the
same debt as the Old 9% Notes and will be issued pursuant to, and entitled to
the benefits of, the Indenture governing the Old 9% Notes (the '9% Note
Indenture').
 
     The form and terms of the New 9 3/4% Notes are identical to the form and
terms of the Old 9 3/4% Notes except that the New 9 3/4% Notes have been
registered under the Securities Act, and will not bear any legends restricting
the transfer thereof. The New 9 3/4% Notes will evidence the same debt as the
Old 9 3/4% Notes and will be issued pursuant to, and entitled to the benefits
of, the Indenture governing the Old 9 3/4% Notes (the '9 3/4% Note Indenture').
The covenants in the 9% Note Indenture are substantially similar to the
covenants in the 9 3/4% Note Indenture. See 'Description of the New Notes.'
 
     The Exchange Offers are being made in order to satisfy certain contractual
obligations of ISP Holdings. There will be no cash proceeds to ISP Holdings from
the exchanges pursuant to the Exchange Offers. See 'The Exchange Offers' and
'Description of the New Notes.' As used herein, (i) the term '9% Notes' means
the Old 9% Notes and the New 9% Notes, treated as a single class, (ii) the term
'9 3/4% Notes' means the Old 9 3/4% Notes and the New 9 3/4% Notes, treated as a
single class, (iii) the term 'Old Notes' means, collectively, the Old 9% Notes
and the Old 9 3/4% Notes, (iv) the term 'New Notes' means, collectively, the New
9% Notes and the New 9 3/4% Notes, (v) the term 'Notes' means, collectively, the
9% Notes and the 9 3/4% Notes and (vi) the term 'Indentures' means the 9% Note
Indenture and the 9 3/4% Note Indenture.
                                                        (continued on next page)
                            ------------------------
 
   
     SEE 'RISK FACTORS' BEGINNING ON PAGE 17 FOR A DISCUSSION OF CERTAIN FACTORS
WHICH HOLDERS OF OLD NOTES SHOULD CONSIDER IN CONNECTION WITH THE EXCHANGE
OFFERS.
    

                            ------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
   EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
     SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
       COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS
         PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
                               CRIMINAL OFFENSE.
                            ------------------------
 
   
              THE DATE OF THIS PROSPECTUS IS               , 1997.
    
<PAGE>
(Continued from front cover)
 
     The New Notes will bear interest from and including their respective dates
of issuance. Holders whose Old Notes are accepted for exchange will receive
accrued interest thereon to, but not including, the date of issuance of such New
Notes, such interest to be payable with the first interest payment on such New
Notes, but will not receive any payment in respect of interest on such Old Notes
accrued after the issuance of such New Notes.
 
     ISP Holdings will accept for exchange any and all Old Notes validly
tendered and not withdrawn prior to 12:00 midnight, New York City time, on
________, 1997 unless extended (as so extended, the 'Expiration Date'). Tenders
of Old Notes may be withdrawn at any time prior to the Expiration Date. The
Exchange Offers are subject to certain customary conditions. See 'The Exchange
Offers.'
 
     Based on no-action letters issued by the staff of the Securities and
Exchange Commission (the 'Commission') to third parties, ISP Holdings believes
that the New Notes issued pursuant to the Exchange Offers may be offered for
resale, resold and otherwise transferred by a holder thereof (other than any
such holder that is an 'affiliate' of ISP Holdings within the meaning of Rule
405 under the Securities Act) without compliance with the registration and
prospectus delivery provisions of the Securities Act, provided that such New
Notes are acquired in the ordinary course of such holder's business, such holder
is not engaging in or does not intend to engage in a distribution of such New
Notes and such holder has no arrangement with any person to participate in the
distribution of such New Notes. Any holder who tenders in either Exchange Offer
for the purpose of participating in a distribution of New Notes cannot rely on
such interpretation by the staff of the Commission and must comply with the
registration and prospectus delivery requirements of the Securities Act in
connection with any secondary resale transactions. Each broker-dealer that
receives New Notes for its own account pursuant to either Exchange Offer must
acknowledge that it will deliver a prospectus meeting the requirements of the
Securities Act in connection with any resales of such New Notes. The letter of
transmittal accompanying this Prospectus (the 'Letter of Transmittal') states
that, by so acknowledging and by delivering a prospectus meeting the
requirements of the Securities Act, a broker-dealer will not be deemed to admit
that it is an 'underwriter' within the meaning of the Securities Act. This
Prospectus, as it may be amended or supplemented from time to time, may be used
by a broker-dealer in connection with resales of New 9% Notes received in

exchange for Old 9% Notes or resales of New 9 3/4% Notes received in exchange
for Old 9 3/4% Notes, in each case where such Old Notes were acquired by such
broker-dealer as a result of market-making activities or other trading
activities. ISP Holdings has agreed that, for a period of 180 days after the
Expiration Date, it will make this Prospectus available to any broker-dealer for
use in connection with any such resale. See 'Plan of Distribution.'
 
     The Notes are redeemable, in whole or in part, at the option of ISP
Holdings at any time on or after October 15, 1999 at the redemption prices
(expressed as percentages of principal amount) set forth herein, plus accrued
and unpaid interest to the redemption date. In the event that prior to October
15, 1999, a sale of common stock of ISP Holdings or certain of its subsidiaries
shall occur, ISP Holdings will have the option to redeem the Notes using the net
cash proceeds received therefrom by ISP Holdings as provided, and subject to the
limitations set forth, in the Indentures.
 
     Each of the New 9% Notes and the New 9 3/4% Notes will be senior unsecured
obligations of ISP Holdings, will rank pari passu with all other unsecured and
unsubordinated obligations of ISP Holdings and will rank pari passu with each
other. ISP Holdings is a holding company which has no subordinated obligations;
consequently, the New Notes, at the time of issuance, will not be senior to any
obligations of ISP Holdings. Upon consummation of the Exchange Offers, the only
outstanding indebtedness for money borrowed of ISP Holdings will be the Notes.
As of September 29, 1996, the outstanding indebtedness for money borrowed of the
subsidiaries of ISP Holdings was $361.4 million and the other outstanding
liabilities reflected on ISP Holdings' consolidated balance sheet, including
trade payables and accrued expenses, was $226.1 million, not including $770.3
million of net noncurrent liabilities of discontinued operations. See
'Management's Discussion and Analysis of Financial Condition and Results of
Operation.' The New Notes will be effectively subordinated to all liabilities of
such subsidiaries. As of September 29, 1996, after giving pro forma effect to
the Transactions (as defined), the outstanding consolidated indebtedness of ISP
Holdings and its then-existing subsidiaries would have been $812.2 million. The
Indentures limit, among other things, the incurrence of additional Debt (as
defined) and the issuance of Preferred Stock (as defined) by ISP Holdings and
its subsidiaries. See 'Risk Factors--Holding Company Structure and Related
Considerations' and 'Description of the New Notes-- Certain Covenants.'
 
     Prior to the Exchange Offers, there has been no public market for the
Notes. ISP Holdings does not intend to list the New 9% Notes or the New 9 3/4%
Notes on any securities exchange or to seek approval for quotation through any
automated quotation system and there can be no assurance that an active public
market for the New 9% Notes or the New 9 3/4% Notes will develop.
 
     Neither Exchange Offer is conditioned upon any minimum principal amount of
Old Notes being tendered for exchange pursuant to such Exchange Offer.


<PAGE>
   
                                    SUMMARY
    
 
      THE FOLLOWING SUMMARY IS QUALIFIED IN ITS ENTIRETY BY THE MORE DETAILED
INFORMATION AND FINANCIAL STATEMENTS APPEARING ELSEWHERE IN THIS PROSPECTUS. AS
USED IN THIS PROSPECTUS, THE COMPANY MEANS ISP HOLDINGS INC. ('ISP HOLDINGS')
AND ITS CONSOLIDATED SUBSIDIARIES AND PREDECESSORS, UNLESS THE CONTEXT OTHERWISE
REQUIRES.
 
                                  THE COMPANY
ISP HOLDINGS
 
   
     The business of ISP Holdings consists of owning approximately 83.5% of the
issued and outstanding common stock of International Specialty Products Inc.
('ISP'). The remaining 17% of the outstanding ISP common stock is publicly held
and traded on the New York Stock Exchange. ISP Holdings was formed in 1996 in
order to consummate the ISP Holdings Transactions (as defined herein), which
were consummated on October 18, 1996. See 'The ISP Holdings Transactions.' Prior
to the Spin Off Transactions (as defined herein), which were consummated on
January 1, 1997, ISP Holdings was a direct wholly owned subsidiary of GAF
Corporation ('GAF'). GAF is controlled by Samuel J. Heyman, Chairman and Chief
Executive Officer of GAF, ISP Holdings, ISP and Building Materials Corporation
of America ('BMCA'). As a result of the Spin Off Transactions, the outstanding
common stock of ISP Holdings is now held directly by the stockholders of GAF.
Mr. Heyman continues to control both ISP Holdings and GAF. See 'Security
Ownership of Certain Beneficial Owners and Management.' GAF was organized by Mr.
Heyman for the purpose of effecting the acquisition in March 1989 of the
predecessor company to GAF in a management-led buyout. ISP Holdings' principal
executive offices are located at 818 Washington Street, Wilmington, Delaware
19801 (telephone (302) 428-0847).
    
 
     The financial information concerning ISP Holdings contained in this
Prospectus has been prepared on a basis which retroactively reflects the
formation of ISP Holdings.
 
ISP
 
     ISP, through its direct and indirect subsidiaries, is a leading
multinational manufacturer of specialty chemicals, mineral products, filter
products and advanced materials (such businesses conducted through the direct
and indirect subsidiaries of ISP, collectively, the 'Chemicals Business'). ISP
produces and markets more than 325 specialty chemicals. These products are sold
in domestic and international markets, primarily for use in branded consumer
products manufactured by multinational companies engaged in relatively
non-cyclical industries such as cosmetics and personal care, pharmaceuticals,
health-related products and beverages. ISP believes that it is one of the two
largest manufacturers of many of the specialty chemicals, mineral products and
advanced materials it produces.
 
     ISP emphasizes sales of higher margin specialty chemicals to niche markets.

These products, while often representing a relatively small portion of its
customers' production costs, generally constitute key ingredients in the end
products in which they are used. ISP believes it has been able to sustain its
market share positions for many of its specialty chemicals by establishing and
maintaining long-term relationships with its customers, working closely with its
customers to develop specialty chemicals tailored to their specific needs,
emphasizing sales for use in branded products that typically are not
reformulated during their life cycles. In addition, because of the specialized
nature of ISP's specialty chemicals and the fact that certain of such chemicals
are sold primarily to relatively non-cyclical industries, ISP believes that
demand for such chemicals is less affected by changes in economic conditions
than is the case with commodity chemical products. See 'Business--ISP.'
 
     During the years ended December 31, 1995 and December 31, 1994 and the nine
months ended September 29, 1996 and October 1, 1995, ISP had net sales of $689
million, $600 million, $544.1 million and $530.3 million, respectively, and
operating income of $106.1 million, $72.5 million, $98.2 million and $81.2
million, respectively.
 
     ISP's strategy for future growth involves (i) the introduction of new
products and the development of new applications for existing products, (ii)
geographic expansion and penetration of new markets, and (iii) selected
acquisitions of businesses which complement ISP's existing businesses. See
'Business--ISP--Strategy.'
 
                                   * * * * *
 
     Statements contained herein as to the Company's competitive position are
based on industry information which the Company believes to be reliable.
 
                                       1
<PAGE>
                           THE SPIN OFF TRANSACTIONS
GENERAL
 
   
     On August 6, 1996, ISP Holdings was formed in Delaware and 10 shares of its
common stock were issued to GAF in exchange for all of the capital stock of G-I
Holdings Inc. ('G-I Holdings'), which resulted in (i) ISP Holdings becoming a
direct wholly owned subsidiary of GAF, (ii) G-I Holdings becoming a direct
wholly-owned subsidiary of ISP Holdings, and (iii) BMCA, U.S. Intec. Inc.
('USI') and GAF Fiberglass Corporation (formerly known as GAF Chemicals
Corporation) ('GFC') becoming indirect wholly-owned subsidiaries of ISP
Holdings. Prior to the consummation of the Spin Off Transactions, ISP Holdings,
through BMCA and USI, was a leading national manufacturer of a broad line of
asphalt roofing products and accessories for the residential and commercial
roofing markets (such businesses, collectively, the 'Building Materials
Business'). GFC owns an investment in Rhone-Poulenc Surfactants & Specialties
L.P., a Delaware partnership which operates, among other businesses, GFC's
former surfactants chemicals business (the 'Surfactants Partnership.')
    
 
   
     On January 1, 1997, GAF effected the Spin Off Transactions. As part of the

Spin Off Transactions, (i) GFC distributed all of the common stock of ISP that
it owned (approximately 83.5% of the issued and outstanding common stock of ISP)
to G Industries Corp. ('G Industries'), which in turn distributed such ISP
common stock to its direct parent, G-I Holdings, which in turn distributed such
ISP common stock to ISP Holdings, (ii) ISP Holdings distributed all of the
common stock of G-I Holdings to GAF and (iii) GAF distributed all of the common
stock of ISP Holdings (whose principal asset was 83% of the issued and
outstanding common stock of ISP) to GAF's stockholders. As a result of such
distributions, ISP Holdings and ISP are no longer direct or indirect
subsidiaries of GAF, while certain other assets and liabilities relating to the
Building Materials Business, including liabilities for asbestos-related claims,
remain part of GAF, but are not assets or liabilities of ISP Holdings. For
information regarding the Building Materials Business, see 'Available
Information.'
    
 
     Prior to consummation of the Spin Off Transactions, GAF received a ruling
(the 'IRS Ruling') from the Internal Revenue Service (the 'IRS') to the effect
that the Spin Off Transactions will not result in recognition of income by GAF
or any members of GAF's federal consolidated tax group (the 'GAF Tax Group').
The IRS Ruling was conditioned upon the accuracy of certain representations
contained in GAF's request for such ruling as to certain facts and circumstances
with respect to the Spin Off Transactions. The GAF Tax Group, which prior to the
Spin Off Transactions included ISP Holdings and ISP, would suffer adverse tax
consequences if the Spin Off Transactions did not qualify as 'tax-free spin
offs.' See 'Risk Factors--Additional Risks Related to the Spin Off
Transactions.' Also see 'Certain Relationships--Mutual Indemnification.'
 
     Prior to consummation of the Spin Off Transactions, GAF also received an
opinion of Houlihan Lokey Howard & Zukin ('HLHZ') regarding the solvency of GAF
and the other companies that engaged in distributions pursuant to the Spin Off
Transactions. See 'The Spin Off Transactions' for a description of such opinion
and the reviews, analyses and inquiries made by HLHZ and the financial
projections, forecasts and other representations provided by GAF and certain of
its subsidiaries and relied upon by HLHZ in rendering such opinion.
 
   
     The following charts illustrate a simplified ownership structure of GAF and
its subsidiaries as it existed prior to the consummation of the Spin Off
Transactions and the current capital structure.
    
 
                                       2
<PAGE>
   
                                       
                      [CHART-Summary Corporate Structure
                      Prior To The Spin Off Transactions]

                                      GAF
                                       | 100%
                                       |
                                 ISP Holdings
                                       | 100%

                         100%          |
                       ---------- G-I Holdings
                       |               | 100%
                       |               |
                       |               |       100%            Public
                       |         G Industries ----- GFC     Shareholders
                       |               |             |           | 
                  U.S. Intec           |             |           | 
                                       | 100%        |           |
                 -----------------------             |           | 
                 |                              83.5%|           |16.5%
                 |                                  ---------------   
               BMCA                                       ISP
                                                    ---------------
    
                                       3
<PAGE>
   
                  [CHART-Summary Existing Corporate Structure]
 
                  GAF                  ISP Holdings
                   | 100%                   |
                   |                        |
              G-I Holdings                  |
                   | 100%             83.5% |
                   |                        |
              G Industries                  | 
                   | 100%                   | 
                   |                        |  Public Shareholders
      +------------|                        |       |            
      |            |                        |       |            
      |            |                        |       |            
 100% |          BMCA                       |       | 16.5%           
      |            | 100%                   |       | 
     GFC           |                        |       |                 
                   |                -------------------           
                US Intec                   ISP                     
                                    -------------------   
    
                                       4
<PAGE>
                         THE ISP HOLDINGS TRANSACTIONS
 
     The Tender Offer, the Old Exchange Offer and the 9% Note Offering (each as
defined below) and the application of the proceeds therefrom are collectively
referred to herein as the 'ISP Holdings Transactions' and, together with the
Spin Off Transactions, the 'Transactions.'
 
TENDER OFFER
 
     On October 18, 1996, ISP Holdings consummated a cash tender offer and
consent solicitation (the 'Tender Offer') for all of the Senior Discount Notes
and Series B Senior Discount Notes due 1998 (the 'Discount Notes') of G-I
Holdings Inc., a wholly owned subsidiary of ISP Holdings prior to consummation
of the Spin Off Transactions ('G-I Holdings'). Approximately 99% of the

outstanding Discount Notes were tendered pursuant to the Tender Offer and
approximately $6.3 million in aggregate principal amount at maturity remain
outstanding. In connection with such offer to purchase, ISP Holdings also
obtained the consent of the tendering holders of the Discount Notes to certain
amendments (the 'Discount Note Amendments') to the Indenture dated as of October
5, 1993 (the 'Discount Note Indenture') between G-I Holdings and the Bank of New
York, as trustee, governing the Discount Notes. The Discount Note Amendments
modified or eliminated certain restrictive covenants contained in the Discount
Note Indenture, including those covenants that would have prohibited the Spin
Off Transactions. Pursuant to the Tender Offer, ISP Holdings paid an aggregate
purchase price of approximately $376.3 million with the proceeds of the 9% Note
Offering and the Repurchase as described below.
 
   
     Concurrently with the consummation of the Tender Offer, ISP Holdings made a
loan to ISP in the amount of $73.2 million (the 'ISP Loan') and G-I Holdings
purchased for cash from ISP Holdings Discount Notes tendered pursuant to the
Tender Offer (the 'Repurchase') in an amount equal to $133 million, which was
sufficient, together with the net proceeds of the 9% Note Offering (after giving
effect to the ISP Loan), to allow ISP Holdings to consummate the Tender Offer
and to pay expenses in connection with the ISP Holdings Transactions. All
remaining Discount Notes validly tendered and purchased in the Tender Offer by
ISP Holdings (approximately $277.0 million at maturity) were held by ISP
Holdings and remained outstanding as obligations of G-I Holdings until
immediately prior to consummation of the Spin Off Transactions, at which time
they were contributed to G-I Holdings as a capital contribution and cancelled by
G-I Holdings. In addition, immediately prior to such capital contribution, at
the time of the Spin Off Transactions, G-I Holdings purchased from ISP Holdings
Discount Notes for an aggregate amount equal to $45.8 million representing the
sum of $45 million and the amount of fees and expenses of ISP Holdings related
to the Spin Off Transactions (not including those fees and expenses already paid
by ISP Holdings related to the ISP Holdings Transactions). All Discount Notes so
purchased were cancelled by G-I Holdings.
    
 
OLD EXCHANGE OFFER
 
   
     On October 18, 1996, ISP Holdings consummated an offer to exchange (the
'Old Exchange Offer') $1,000 principal amount of the Old 9 3/4% Notes for each
$1,000 principal amount of G-I Holdings' Series B 10% Senior Notes due 2006 (the
'10% Notes'). Pursuant to the Old Exchange Offer, on October 18, 1996, Old
9 3/4% Notes in the aggregate principal amount of $199,871,000 were issued to
the former holders of the 10% Notes. Approximately 99% of the outstanding 10%
Notes were tendered pursuant to the Old Exchange Offer and approximately $0.1
million in aggregate principal amount remain outstanding. All 10% Notes validly
tendered and accepted in the Old Exchange Offer were held by ISP Holdings and
remained outstanding as obligations of G-I Holdings until immediately prior to
consummation of the Spin Off Transactions, at which time such 10% Notes were
contributed to G-I Holdings by ISP Holdings as a capital contribution and
cancelled by G-I Holdings. In connection with such exchange offer, ISP Holdings
also obtained the consent of the tendering holders of the 10% Notes to certain
amendments (the '10% Note Amendments') to the Indenture dated as of February 14,
1996 (the '10% Note Indenture') between G-I Holdings and the Bank of New York,

as trustee, governing the 10% Notes. The 10% Note Amendments modified or
eliminated certain restrictive covenants contained in the 10% Note Indenture,
including those covenants that would have prohibited the Spin Off Transactions.
    
 
                                       5
<PAGE>
THE 9% NOTE OFFERING
 
   
     On October 18, 1996, ISP Holdings issued and sold $325 million in aggregate
principal amount of the Old 9% Notes in a private placement (the '9% Note
Offering'). ISP Holdings received net proceeds of $317,187,000 pursuant to the
9% Note Offering.
    
 
   
                                   * * * * *
    
 
   
     The following chart summarizes the various debt instruments involved in the
ISP Holdings Transactions and the Exchange Offers.
    
 
   
<TABLE>
<CAPTION>
                  DISCOUNT NOTES    10% NOTES         OLD 9% NOTES      NEW 9% NOTES      OLD 9 3/4% NOTES  NEW 9 3/4% NOTES
                  ----------------  ----------------  ----------------  ----------------  ----------------  ----------------
<S>               <C>               <C>               <C>               <C>               <C>               <C>
Obligor:          G-I Holdings      G-I Holdings      ISP Holdings      ISP Holdings      ISP Holdings      ISP Holdings
- ----------------------------------------------------------------------------------------------------------------------------
Issuance Date:    October 5, 1993   February 14,      October 18, 1996  To be issued      October 18, 1996  To be issued
                                    1996                                upon                                upon
                                                                        consummation of                     consummation of
                                                                        the 9% Note                         the 9 3/4%
                                                                        Exchange Offer                      Exchange Offer
- ----------------------------------------------------------------------------------------------------------------------------
Reason for        Proceeds used to  Issued in         Proceeds used to  To be issued in   Issued in         To be issued in
Issuance:         redeem old        connection with   finance the       exchange for Old  connection with   exchange for Old
                  issuance of debt  exchange offer    Tender Offer      9% Notes          exchange offer    9 3/4% Notes
                  securities of     for Discount                                          for 10% Notes
                  G-I Holdings and  Notes
                  reduce
                  additional debt
                  of G-I Holdings
- ----------------------------------------------------------------------------------------------------------------------------
Principal Amount  $6,343,000        $132,000          $325,000,000      N/A               $199,871,000      N/A
Outstanding as
of January 1,
1997:
</TABLE>
    

 
                                       6


<PAGE>
                              THE EXCHANGE OFFERS
 
     The Exchange Offers are being made with respect to all of ISP Holdings'
outstanding 9% Senior Notes due 2003 (the 'Old 9% Notes') and 9 3/4% Senior
Notes due 2002 (the 'Old 9 3/4% Notes'). The form and terms of each issue of New
Notes are the same as the form and terms of the respective issue of Old Notes,
except that, in each case, the New Notes have been registered under the
Securities Act and, therefore, will not bear legends restricting the transfer
thereof. Each issue of New Notes will evidence the same debt as the respective
issue of Old Notes and will be entitled to the benefits of the Indenture
pursuant to which such Old Notes were issued. The Old Notes and the New Notes
are sometimes referred to collectively herein as the 'Notes.' See 'Description
of the New Notes.'
 
<TABLE>
<S>                                         <C>
The Exchange Offers.......................  (i) $1,000 principal amount of New 9% Notes in exchange for each
                                              $1,000 principal amount of Old 9% Notes. As of the date hereof,
                                              $325,000,000 aggregate principal amount of the Old 9% Notes are
                                              outstanding. The terms of the New 9% Notes and the Old 9% Notes are
                                              substantially identical.
 
                                            (ii) $1,000 principal amount of New 9 3/4% Notes in exchange for each
                                              $1,000 principal amount of Old 9 3/4% Notes. As of the date hereof,
                                              $199,871,000 aggregate principal amount of the Old 9 3/4% Notes are
                                              outstanding. The terms of the New 9 3/4% Notes and the Old 9 3/4%
                                              Notes are substantially identical.
 
                                            Based on an interpretation by the staff of the Commission set forth
                                              in no-action letters issued to third parties, ISP Holdings believes
                                              that New Notes issued pursuant to the Exchange Offers in exchange
                                              for Old Notes may be offered for resale, resold and otherwise
                                              transferred by a holder thereof (other than any such holder that is
                                              an 'affiliate' of ISP Holdings within the meaning of Rule 405
                                              promulgated under the Securities Act), without compliance with the
                                              registration and prospectus delivery provisions of the Securities
                                              Act, provided that (i) such New Notes are acquired in the ordinary
                                              course of business of such holder, (ii) such holder is not engaging
                                              in or does not intend to engage in a distribution of such New
                                              Notes, and (iii) such holder does not have an arrangement or
                                              understanding with any person to participate in the distribution of
                                              such New Notes. Any holder who tenders in the Exchange Offers for
                                              the purpose of participating in a distribution of the New Notes
                                              cannot rely on such interpretation by the staff of the Commission
                                              and must comply with the registration and prospectus delivery
                                              requirements of the Securities Act in connection with a secondary
                                              resale transaction. Each broker-dealer that receives New Notes for
                                              its own account in exchange for Old Notes, where such Old Notes
                                              were acquired by such broker-dealer as a result of market-making
                                              activities or other trading activities, must acknowledge that it
                                              will deliver a prospectus meeting the requirements of the
                                              Securities Act in connection with any resales of such New Notes.
                                              See 'The Exchange Offers--Purpose and Effect' and 'Plan of

                                              Distribution.'
 
Registration Agreements...................  (i) The Old 9% Notes were issued by ISP Holdings on October 18, 1996
                                              in the 9% Note Offering. In connection therewith, ISP Holdings
                                              agreed to use its best efforts to cause a registration statement to
                                              become effective with respect to an exchange offer of a new
                                              security for the Old 9% Notes (the '9% Note
</TABLE>
 
                                       7
<PAGE>
 
<TABLE>
<S>                                         <C>
                                              Registration Agreement'). See 'The Exchange Offers--Purpose and
                                              Effect.'
 
                                            (ii) The Old 9 3/4% Notes were issued pursuant to a private placement
                                              by ISP Holdings on October 18, 1996 in the Old Exchange Offer. In
                                              connection therewith, ISP Holdings agreed to use its best efforts
                                              to cause a registration statement to become effective with respect
                                              to an exchange offer of a new security for the Old 9 3/4% Notes
                                              (the '9 3/4% Note Registration Agreement' and, together with the 9%
                                              Note Registration Agreement, the 'Registration Agreements'). See
                                              'The Exchange Offers--Purpose and Effect.'
 
Expiration Date...........................  Each Exchange Offer will expire at 12:00 midnight, New York City
                                              time, on              , 1997, or at such later date or time to
                                              which it is extended (as so extended, the 'Expiration Date'). ISP
                                              Holdings does not intend to extend either Exchange Offer, although
                                              it reserves the right to do so.
 
Withdrawal................................  The tender of Old Notes pursuant to either Exchange Offer may be
                                              withdrawn at any time prior to 12:00 midnight, New York City time,
                                              on the Expiration Date. Any Old Notes not accepted for exchange for
                                              any reason will be returned without expense to the tendering holder
                                              thereof as promptly as practicable after the expiration or
                                              termination of the Exchange Offers.
 
Interest on the New Notes and
  Old Notes...............................  (i) The 9% Notes will pay interest on the principal thereof at the
                                            rate of 9% per annum, payable on April 15 and October 15 each year,
                                              commencing on April 15, 1997, to the persons who are registered
                                              holders on the immediately preceding April 1 and October 1. See
                                              'Description of the New Notes--Principal, Maturity and Interest.'
 
                                            (ii) The 9 3/4% Notes will pay interest on the principal thereof at
                                              the rate of 9 3/4% per annum, payable on February 15 and August 15
                                              each year, commencing on February 15, 1997, to the persons who are
                                              registered holders on the immediately preceding February 1 and
                                              August 1. See 'Description of the New Notes--Principal, Maturity
                                              and Interest.'
 
Conditions to the Exchange Offers.........  The Exchange Offers are subject to certain customary conditions, each

                                              of which may be waived by ISP Holdings. Neither Exchange Offer is
                                              conditioned upon any principal amount of Old Notes being tendered
                                              for exchange pursuant to such Exchange Offer. See 'The Exchange
                                              Offers--Conditions.'
 
Procedures for Tendering Old Notes........  Each holder of Old Notes wishing to accept the applicable Exchange
                                              Offer must complete, sign and date the applicable Letter of
                                              Transmittal, or a facsimile thereof, in accordance with the
                                              instructions contained herein and therein, and mail or otherwise
                                              deliver such Letter of Transmittal, or such facsimile, together
                                              with such Old Notes and any other required documentation, to The
                                              Bank of New York (the 'Exchange Agent') at the address set forth
                                              herein. Tendered Old Notes must be received by the Exchange Agent
                                              by 12:00 midnight, New York City time, on the Expiration Date. By
                                              executing the Letter of Transmittal, each
</TABLE>
 
                                       8
<PAGE>
 
   
<TABLE>
<S>                                         <C>
                                              holder will represent to the Company that, among other things, (i)
                                              the New Notes acquired pursuant to the applicable Exchange Offer
                                              are being obtained in the ordinary course of business of such
                                              holder, (ii) the holder is not engaging in and does not intend to
                                              engage in a distribution of such New Notes, (iii) the holder does
                                              not have an arrangement or understanding with any person to
                                              participate in the distribution of such New Notes, and (iv) the
                                              holder is not an 'affiliate,' as defined under Rule 405 promulgated
                                              under the Securities Act, of the Company. Pursuant to the
                                              Registration Agreements, the Company is required to file a
                                              registration statement for a continuous offering pursuant to Rule
                                              415 under the Securities Act in respect of the Old Notes of any
                                              holder that would not receive freely tradeable New Notes in either
                                              Exchange Offer or is ineligible to participate in such Exchange
                                              Offer and indicates that it wishes to have its Old Notes registered
                                              under the Securities Act. See 'The Exchange Offers-- Procedures for
                                              Tendering.'
 
Book-Entry Transfer.......................  The Exchange Agent will make a request to establish separate accounts
                                              with respect to the Old Notes at the Book-Entry Transfer Facility
                                              (as defined herein) for purposes of the Exchange Offers within two
                                              business days after receipt of this Prospectus, and any financial
                                              institution that is a participant in the Book-Entry Transfer
                                              Facility's systems may make book-entry delivery of Old Notes by
                                              causing the Book-Entry Transfer Facility to transfer such Old Notes
                                              into the Exchange Agent's account at the Book-Entry Transfer
                                              Facility in accordance with such Book-Entry Transfer Facility's
                                              procedures for transfer. However, although delivery of Old Notes
                                              may be effected through book-entry transfer at the Book-Entry
                                              Transfer Facility, the Letter of Transmittal (or facsimile
                                              thereof), with any required signature guarantees and any other

                                              required documents, must, in any case, be transmitted to and
                                              received by the Exchange Agent at its address set forth herein on
                                              or prior to the Expiration Date or the guaranteed delivery
                                              procedures described below must be complied with.
 
Special Procedures for
  Beneficial Owner........................  Any beneficial owner whose Old Notes are registered in the name of a
                                              broker, dealer, commercial bank, trust company, or other nominee
                                              (with respect to each issue of New Notes, each, a 'Registered
                                              Holder') and who wishes to tender such Old Notes should contact the
                                              Registered Holder promptly and instruct such Registered Holder to
                                              tender on such beneficial owner's behalf. If such beneficial owner
                                              wishes to tender on such owner's own behalf, such owner must, prior
                                              to completing and executing the Letter of Transmittal and
                                              delivering such owner's Old Notes, either make appropriate
                                              arrangements to register ownership of the Old Notes in such
                                              beneficial owner's name or obtain a properly completed bond power
                                              from the Registered Holder. The transfer of registered ownership
                                              may take considerable time. See 'The Exchange Offers--Procedures
                                              for Tendering.'
 
Guaranteed Delivery Procedures............  If a Registered Holder of the applicable issue of Old Notes desires
                                            to tender such Old Notes and the Old Notes are not immediately
</TABLE>
    
 
                                       9
<PAGE>
 
<TABLE>
<S>                                         <C>
                                              available, or time will not permit such holder's Old Notes or other
                                              required documents to reach the Exchange Agent before the
                                              Expiration Date, or the procedure for book-entry transfer cannot be
                                              completed on a timely basis, a tender may be effected according to
                                              the guaranteed delivery procedures set forth in 'The Exchange
                                              Offers--Guaranteed Delivery Procedures.'
 
Acceptance of Old Notes and Delivery of
  New Notes...............................  The Company will accept for exchange any and all Old Notes which are
                                              properly tendered in the Exchange Offers prior to 12:00 midnight,
                                              New York City time, on the Expiration Date. The New Notes issued
                                              pursuant to the Exchange Offers will be delivered promptly
                                              following the Expiration Date. See 'The Exchange Offers--Terms of
                                              the Exchange Offers.'
 
Exchange Agent............................  The Bank of New York is serving as the Exchange Agent in connection
                                              with the Exchange Offers.
 
Consequences of Failure to
  Exchange................................  The liquidity of the market for a holder's Old Notes could be
                                              adversely affected upon completion of the relevant Exchange Offer
                                              if such holder does not participate in such Exchange Offer. See
                                              'The Exchange Offers--Consequences of Failure to Exchange.'

 
Federal Income Tax Consequences...........  The exchange pursuant to either Exchange Offer should not be a
                                              taxable event for federal income tax purposes. See 'Certain Federal
                                              Income Tax Considerations.'
</TABLE>
 
                                       10

<PAGE>
                             TERMS OF THE NEW NOTES
 
   
<TABLE>
<S>                                         <C>
Issuer....................................  ISP Holdings Inc.
 
Issues....................................  (i) Up to $325,000,000 aggregate principal amount at maturity of
                                              Series B 9% Senior Notes due 2003 (the 'New 9% Notes').
 
                                            (ii) Up to $199,871,000 aggregate principal amount at maturity of
                                              Series B 9 3/4% Senior Notes due 2002 (the 'New 9 3/4% Notes').
 
Maturities................................  (i) October 15, 2003, with respect to the New 9% Notes.
 
                                            (ii) February 15, 2002, with respect to the New 9 3/4% Notes.
 
Interest and Interest Payment Dates.......  (i) The New 9% Notes will accrue interest at the rate of 9% per annum
                                              accruing from the date of issuance or the most recent interest
                                              payment date to which interest has been paid.
 
                                            (ii) The New 9 3/4% Notes will accrue interest at the rate of 9 3/4%
                                              per annum accruing from the date of issuance or the most recent
                                              interest payment date to which interest has been paid.
 
Optional Redemption.......................  Each of the New 9% Notes and the New 9 3/4% Notes is redeemable, in
                                              whole or in part, at the option of ISP Holdings at any time on or
                                              after October 15, 1999 at the redemption prices (expressed as
                                              percentages of principal amount) set forth herein, plus accrued and
                                              unpaid interest to the redemption date. In addition, prior to
                                              October 15, 1999, an amount of each issue of New Notes representing
                                              an aggregate of up to 50% of the then outstanding amount of such
                                              issue of New Notes will be redeemable at the option of ISP Holdings
                                              from the net cash proceeds of an issuance of common stock of ISP
                                              Holdings or an issuance or sale of Common Stock of ISP, at 109% in
                                              the case of the New 9% Notes, or 109.75% in the case of the New
                                              9 3/4% Notes, of the principal amount thereof plus accrued interest
                                              thereon to the date of redemption, provided that, after giving
                                              effect to any such redemption, not less than a majority of the
                                              principal amount of such 9% Notes or 9 3/4% Notes, as the case may
                                              be, originally issued would be outstanding.
 
Change of Control Put and Call............  Upon the occurrence of a Change of Control (as defined), each holder
                                              of New Notes will have the right to require the Company to
                                              repurchase such holder's New Notes at a purchase price of 101% of

                                              the principal amount of such New Notes (or, if lower, the
                                              applicable redemption prices then in effect under the provisions
                                              described in the first and fourth paragraphs under 'Description of
                                              the New Notes--Optional Redemption'), plus accrued and unpaid
                                              interest, if any, to the repurchase date, and the Company will have
                                              the option to redeem the New Notes in whole at a redemption price
                                              equal to the then outstanding principal amount, plus the Applicable
                                              Premium (as defined), plus accrued and unpaid interest, if any, to
                                              the redemption date. See 'Risk Factors--Change of Control;
                                              Acceleration of Debt.'
 
Ranking and Holding Company Structure.....  Each of the New 9% Notes and the New 9 3/4% will be senior unsecured
                                              obligations of ISP Holdings and will rank pari passu with all other
                                              unsecured and unsubordinated obligations of ISP
</TABLE>
    
 
                                       11
<PAGE>
 
   
<TABLE>
<S>                                         <C>
                                              Holdings and will rank pari passu with each other. Immediately
                                              following the issuance of the New Notes, ISP Holdings will not have
                                              any indebtedness for money borrowed that ranks pari passu with, or
                                              senior to, the Notes or any subordinated obligations. Upon
                                              consummation of the Exchange Offers, the only outstanding
                                              indebtedness for money borrowed of ISP Holdings will be the 9%
                                              Notes and the 9 3/4% Notes.
 
                                            ISP Holdings is a holding company, and therefore the New Notes will
                                              be effectively subordinated to all existing and future liabilities,
                                              including indebtedness, of subsidiaries of ISP Holdings. As of
                                              September 29, 1996, such subsidiaries had outstanding indebtedness
                                              for money borrowed of $361.4 million and other outstanding
                                              liabilities reflected on ISP Holdings' consolidated balance sheet,
                                              including trade payables and accrued expenses, of $226.1 million,
                                              not including $770.3 million of net noncurrent liabilities of
                                              discontinued operations. The Indentures governing the Notes (the
                                              'Indentures') limit, among other things, the incurrence of
                                              additional Debt (as defined) and the issuance of Preferred Stock
                                              (as defined) by ISP Holdings and its subsidiaries. See 'Risk
                                              Factors--Holding Company Structure and Related Considerations' and
                                              'Description of the New Notes--Certain Covenants.'
 
Certain Covenants.........................  The Indentures limit the Company and its subsidiaries from incurring
                                              additional Debt, issuing Preferred Stock and incurring Liens (as
                                              defined). The Indentures also contain covenants that, among other
                                              things, limit the ability of the Company and its subsidiaries to
                                              pay certain dividends or make certain other Restricted Payments (as
                                              defined) and Restricted Investments (as defined), engage in
                                              transactions with Affiliates (as defined) and agree to certain
                                              additional limitations on dividends and other payment restrictions

                                              affecting subsidiaries. The Indentures also limit the ability of
                                              the Company to consolidate or merge with, or transfer all or
                                              substantially all of its assets to, another person. However, all
                                              such covenants are subject to a number of important qualifications
                                              and exceptions. The Indentures permitted the consummation of the
                                              Spin Off Transactions and, as a result of the Spin Off
                                              Transactions, G-I Holdings and its subsidiaries, including BMCA,
                                              are no longer subsidiaries of ISP Holdings and therefore are not
                                              subject to the restrictions contained in the Indentures. See 'Risk
                                              Factors--Restrictions Imposed by Indebtedness' and 'Description of
                                              the New Notes--Certain Covenants.'
 
Registration Rights.......................  ISP Holdings has agreed to use its best efforts to cause to become
                                              effective by February 14, 1997 a registration statement with
                                              respect to the Exchange Offers. In the event that the Exchange
                                              Offers are not completed by April 16, 1997, ISP Holdings will use
                                              its best efforts to cause to become effective a shelf registration
                                              statement with respect to the resale of the Old Notes and to keep
                                              such shelf registration statement effective until three years after
                                              the date of original issuance of the Old Notes.
 
                                            If by April 16, 1997 (i) the Exchange Offer with respect to an issue
                                              of Old Notes is not completed and (ii) no shelf registration
</TABLE>
    
 
                                       12
<PAGE>
 
<TABLE>
<S>                                         <C>
                                              statement with respect to the resale of such Old Notes is declared
                                              effective, additional interest will accrue on such Old Notes from
                                              and including April 16, 1997 until but excluding the earlier of (i)
                                              the completion of the Exchange Offer and (ii) the effective date of
                                              such shelf registration statement. Such additional interest will be
                                              payable in cash semiannually in arrears on April 15 and October 15
                                              in the case of the 9% Notes, or February 15 and August 15, in the
                                              case of the 9 3/4% Notes, at a rate per annum equal to 0.50% of the
                                              aggregate principal amount outstanding of such issue of Old Notes.
                                              See 'Description of the New Notes-- Principal, Maturity and
                                              Interest' and 'The Exchange Offers-- Purpose and Effect.'
 
Use of Proceeds...........................  There will be no cash proceeds to ISP Holdings from the exchanges
                                              pursuant to the Exchange Offers.
 
Risk Factors..............................  Prospective holders of the New Notes should carefully consider the
                                              specific factors set forth under 'Risk Factors,' as well as the
                                              other information and data included in this Prospectus.
</TABLE>
 
                                       13


<PAGE>
                             SUMMARY FINANCIAL DATA
 
   
     Set forth below are summary consolidated financial data of ISP Holdings and
its subsidiaries. The results of any interim period are not necessarily
indicative of the results to be expected for the full year. The pro forma
balance sheet data give effect to the Transactions as if they had been completed
as of September 29, 1996. The pro forma operating data give effect to the
Transactions as if they had been completed as of January 1, 1995. The Exchange
Offers will not affect the amount of the Company's long-term debt or
stockholder's equity. The pro forma financial information does not purport to
project the financial position or the results of operations for any future
period or to represent what the financial position or results of operations
would have been if the Transactions had been completed at the dates indicated.
All financial data relating to ISP Holdings and its subsidiaries contained
herein have been prepared to retroactively reflect the formation of ISP
Holdings.
    
<TABLE>
<CAPTION>
                                                                                                  NINE MONTHS ENDED
                                                               YEAR ENDED DECEMBER 31,      ------------------------------
                                                              --------------------------    OCT. 1, 1995    SEPT. 29, 1996
                                                               1993      1994      1995     (UNAUDITED)      (UNAUDITED)
                                                              ------    ------    ------    ------------    --------------
                                                                            (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                                           <C>       <C>       <C>       <C>             <C>
OPERATING DATA:
Net sales..................................................   $548.3    $600.0    $689.0       $530.3           $544.1
Operating income...........................................     65.1      99.2     127.1         99.2            105.7
Interest expense...........................................     24.5      28.7      33.1         24.8             21.9
Income from continuing operations before income taxes and
  extraordinary item.......................................     49.8      72.5     106.1         81.2             98.2
Income from continuing operations before extraordinary
  item.....................................................     23.8      37.1      55.1         41.8             51.8
Ratio of earnings to fixed charges(1)......................     2.83      3.32      4.06         4.08             5.23
</TABLE> 
 
<TABLE>
<CAPTION>
                                                                                              SEPTEMBER 29, 1996
                                                                                    ---------------------------------------
                                                                                                   PRO FORMA (GIVING EFFECT
                                                                    DECEMBER 31,      ACTUAL         TO THE TRANSACTIONS)
                                                                        1995        (UNAUDITED)          (UNAUDITED)
                                                                    ------------    -----------    ------------------------
                                                                                         (IN MILLIONS)
<S>                                                                 <C>             <C>            <C>
BALANCE SHEET DATA:
Cash and short-term investments..................................     $  150.0       $   111.7             $  156.7
Total working capital............................................        290.0           413.0                220.9
Total assets.....................................................      1,460.4         1,537.3              1,361.1
Long-term debt less current maturities(2)........................        280.3           239.8                789.3

Total stockholder's equity (deficit).............................         (1.7)           61.7                196.4
</TABLE>
 
   
<TABLE>
<CAPTION>
                                                                                                NINE MONTHS ENDED
                                                           YEAR ENDED DECEMBER 31,      ----------------------------------
                                                          --------------------------     OCT. 1, 1995      SEPT. 29, 1996
                                                           1993      1994      1995      (UNAUDITED)        (UNAUDITED)
                                                          ------    ------    ------    --------------    ----------------
                                                                          (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                                       <C>       <C>       <C>       <C>               <C>
OTHER DATA:
Depreciation...........................................   $ 28.7    $ 32.8    $ 36.0        $ 26.7             $ 28.2
Goodwill amortization..................................     13.9      13.4      13.2           9.9                9.9
Capital expenditures and acquisitions..................     62.9      31.1      38.9          26.6               35.7
Cash Flows from:
  Operating activities.................................    111.8      75.9     143.8          97.7               82.5
  Investing activities.................................    (61.7)    (27.2)   (124.4)        (98.0)               5.0
  Financing activities.................................    (50.3)    (39.6)    (25.5)         (9.4)             (89.8)
Adjusted EBITDA(3).....................................    167.5     225.8     245.6         190.8              219.8
Ratio of Adjusted EBITDA to Adjusted Interest
  Expense(3)...........................................     2.32      2.36      2.16          2.27               2.47
</TABLE>
    
 
                                       14
<PAGE>
 
<TABLE>
<CAPTION>
                                                                               YEAR ENDED          NINE MONTHS ENDED
                                                                              DECEMBER 31,   ------------------------------
                                                                                  1995       OCT. 1, 1995    SEPT. 29, 1996
                                                                              (UNAUDITED)     (UNAUDITED)     (UNAUDITED)
                                                                              ------------   -------------   --------------
                                                                                    (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                                                           <C>            <C>             <C>
PRO FORMA OPERATING DATA(4):
Interest Expense............................................................     $ 78.8          $59.1           $ 56.2
Income from continuing operations...........................................       25.3           19.5             29.4
Ratio of earnings to fixed charges(1).......................................       1.79           1.80             2.16
Ratio of Adjusted EBITDA to Adjusted Interest Expense(3)....................       2.32           2.37             2.83
</TABLE>
 
- ------------------
(1) For purposes of these computations, earnings consist of income from
    continuing operations before income taxes, minority interest and
    extraordinary items plus fixed charges. Fixed charges consist of interest on
    indebtedness (including amortization of debt issuance costs) plus that
    portion of lease rental expense representative of interest (estimated to be
    one-third of lease rental expense).
 

(2) See 'Capitalization' and Note 8 to Consolidated Financial Statements.
 
   
(3) The Adjusted EBITDA data are being presented because such data relate to
    debt covenants under the Indentures. The calculation of the ratio of
    Adjusted EBITDA to Adjusted Interest Expense has been performed in
    accordance with the definitions in the Indentures. See 'Description of the
    New Notes.' Accordingly, Adjusted EBITDA is calculated as income from
    continuing operations before income taxes, plus income (loss) from
    discontinued operations before income taxes, less extraordinary items,
    increased by interest expense, depreciation and goodwill amortization and
    excluding equity in earnings of the GAF-Huls joint venture and Surfactants
    Partnership income, except to the extent distributed in cash. Adjusted
    Interest Expense is calculated as total interest expense excluding interest
    expense on non-recourse debt related to the Surfactants Partnership. As an
    indicator of the Company's operating performance, such supplemental
    financial information should not be considered as an alternative to net
    income or any other measure of performance under generally accepted
    accounting principles.
    
 
    Certain restrictions exist as to the amounts available for making loans,
    paying dividends and otherwise making distributions to ISP Holdings by ISP,
    which restrictions are not, in accordance with the Indentures, given effect
    in the foregoing calculations. See 'Risk Factors--Holding Company Structure
    and Related Considerations.'
 
    The details of the calculations of Adjusted EBITDA and Adjusted Interest
    Expense are set forth in the table on the following page.
 
(4) For an explanation of adjustments to arrive at 'Pro Forma Operating Data,'
    see 'Notes to Selected Financial Data.'
 
                                       15
<PAGE>
   
<TABLE>
<CAPTION>
                                                                                                       PRO FORMA
                                                                                                ------------------------
                                                                        NINE MONTHS ENDED          YEAR      NINE MONTHS
                                                                    --------------------------     ENDED        ENDED
                                      YEAR ENDED DECEMBER 31,         OCT. 1,      SEPT. 29,      DEC. 31,      OCT. 1,
                                   ------------------------------      1995          1996           1995         1995
                                     1993       1994       1995     (UNAUDITED)   (UNAUDITED)   (UNAUDITED)  (UNAUDITED)
                                   --------   --------   --------   -----------   -----------   -----------  -----------
                                                                                  (THOUSANDS)
<S>                                <C>        <C>        <C>        <C>           <C>           <C>          <C>
Income from continuing operations
  before income taxes and
  extraordinary item.............  $ 49,823   $ 72,484   $106,102    $  81,205      $ 98,202     $  60,352    $  46,892
Add (Deduct):
  Loss from discontinued
    operations before income

    taxes........................   (15,649)    (7,430)   (39,642)     (23,826)      (25,414)           --           --
Less:
  Extraordinary items............        --     (1,237)        --           --            --            --           --
Add Continuing Operations:
  Interest expense...............    24,500     28,676     33,091       24,821        21,879        78,841       59,134
  Depreciation...................    28,737     32,753     35,960       26,698        28,183        35,960       26,698
  Goodwill amortization..........    13,856     13,400     13,223        9,922         9,900        13,223        9,922
Add Discontinued Operations:
  Interest expense...............    88,636     93,968    112,460       83,160        91,056            --           --
  Depreciation...................    14,649     16,965     20,421       14,644        18,168            --           --
  Goodwill amortization..........       619      1,041      1,148          783         1,154            --           --
Less:
  Surfactants Partnership income,
    gross........................   (42,920)   (51,190)   (32,380)     (24,285)      (24,218)           --           --
  Equity in earnings of joint
    venture......................    (2,051)    (2,034)    (5,413)      (2,950)       (4,948)       (5,413)      (2,950)
Add:
  Distributions from Surfactants
    Partnership..................     1,951     24,024        295          221           154            --           --
  Dividends received from joint
    venture......................     5,377      4,363        310          310         5,689           310          310
                                   --------   --------   --------   -----------   ------------  -----------  -----------
Adjusted EBITDA..................  $167,528   $225,783   $245,575    $ 190,703      $219,805     $ 183,273    $ 140,006
                                   --------   --------   --------   -----------   ------------  -----------  -----------
                                   --------   --------   --------   -----------   ------------  -----------  -----------
Interest expense-continuing
  operations.....................  $ 24,500   $ 28,676   $ 33,091    $  24,821      $ 21,879     $  78,841    $  59,134
Interest expense-discontinued
  operations.....................    88,636     93,968    112,460       83,160        91,056            --           --
                                   --------   --------   --------   -----------   ------------  -----------  -----------
Total interest expense...........   113,136    122,644    145,551      107,981       112,935        78,841       59,134
Less:
  Interest expense on
    non-recourse debt............   (40,969)   (27,166)   (32,085)     (24,064)      (24,064)           --           --
                                   --------   --------   --------   -----------   ------------  -----------  -----------
Adjusted Interest Expense........  $ 72,167   $ 95,478   $113,466    $  83,917      $ 88,871     $  78,841    $  59,134
                                   --------   --------   --------   -----------   ------------  -----------  -----------
                                   --------   --------   --------   -----------   ------------  -----------  -----------
 
<CAPTION>
[Table Re-Stubbed From Above] 
                                   NINE MONTHS
                                      ENDED
                                    SEPT. 29,
                                      1996
                                   (UNAUDITED)
                                   -----------
 
<S>                               <C>
Income from continuing operations
  before income taxes and
  extraordinary item.............   $  63,889
Add (Deduct):
  Loss from discontinued

    operations before income
    taxes........................          --
Less:
  Extraordinary items............          --
Add Continuing Operations:
  Interest expense...............      56,192
  Depreciation...................      28,183
  Goodwill amortization..........       9,900
Add Discontinued Operations:
  Interest expense...............          --
  Depreciation...................          --
  Goodwill amortization..........          --
Less:
  Surfactants Partnership income,
    gross........................          --
  Equity in earnings of joint
    venture......................      (4,948)
Add:
  Distributions from Surfactants
    Partnership..................          --
  Dividends received from joint
    venture......................       5,689
                                   -----------
Adjusted EBITDA..................   $ 158,905
                                   -----------
                                   -----------
Interest expense-continuing
  operations.....................   $  56,192
Interest expense-discontinued
  operations.....................          --
                                   -----------
Total interest expense...........      56,192
Less:
  Interest expense on
    non-recourse debt............          --
                                   -----------
Adjusted Interest Expense........   $  56,192
                                   -----------
                                   -----------
</TABLE>
    
 
                                       16


<PAGE>
                                  RISK FACTORS
 
     In addition to the other matters described in this Prospectus, the
following risk factors should be carefully considered by each holder of Old
Notes before accepting the applicable Exchange Offer, although the risk factors
set forth below are generally applicable to the Old Notes as well as the New
Notes.
 
SUBSTANTIAL LEVERAGE
 
     The Company has substantial consolidated debt outstanding. At September 29,
1996, the Company had total outstanding consolidated long-term debt of $239.8
million and total common stockholder's equity of $61.7 million. At September 29,
1996, on a pro forma basis, after giving effect to the Transactions, the Company
would have had total outstanding consolidated long-term debt of $789.3 million
and total common stockholder's equity of $196.4 million. The Exchange Offers
will not affect the amount of the Company's long-term debt or shareholder's
equity. The substantial leverage of the Company has important consequences for
holders of the Notes, including the risk that the Company may not generate
sufficient cash flow from operations to pay principal and interest on its
indebtedness or to invest in its businesses. While the Company believes, based
upon its historical and anticipated performance, that it should be able to
satisfy its obligations (including interest on and principal of the Notes) from
operations and appropriate financings and otherwise, no assurance to that effect
can be given. While other measures to raise cash to satisfy obligations include
potential sales of assets or equity, the Company's ability to raise funds by
selling either assets or equity or debt securities is dependent on results of
operations and market conditions. In addition, if ISP Holdings owns less than
80% of the common stock, par value $.01 per share (the 'ISP Common Stock'), of
ISP, payments pursuant to its Tax Sharing Agreement with ISP (the 'ISP Holdings
Tax Sharing Agreement') would not be available to ISP Holdings. See 'Tax Sharing
Agreement.' In the event that the Company is unable to refinance indebtedness or
raise funds through sales of assets or equity or debt securities or otherwise,
its ability to pay principal of and interest on the Notes would be adversely
affected. See Note 8 of Notes to Consolidated Financial Statements and
'Management's Discussion and Analysis of Financial Condition and Results of
Operations--Liquidity and Financial Condition.'
 
CHANGE OF CONTROL; ACCELERATION OF DEBT
 
   
     ISP and its principal domestic subsidiaries are parties to a Credit
Agreement, dated July 26, 1996 (the 'ISP Credit Agreement'), with The Chase
Manhattan Bank, as Agent, and the banks named therein, that provides for a $400
million unsecured revolving credit facility, $75 million of which may be made
available for commercial and standby letters of credit. It is an event of
default under the ISP Credit Agreement if at any time, among other things, (i)
any person or group of related persons (other than Samuel J. Heyman and his
affiliates) shall, on any date, control at least as much of the voting stock of
ISP as is owned, directly or indirectly, by Mr. Heyman and his affiliates on
such date, (ii) Mr. Heyman and his affiliates, directly or indirectly, shall own
less than 25% of the voting stock of ISP outstanding on any date and any other
person or group of related persons shall control an amount of voting stock

greater than one half of the amount of voting stock of ISP owned by Mr. Heyman
and his affiliates on such date, or (iii) Mr. Heyman and his affiliates shall,
on any date, cease to own, directly or indirectly, at least 10% of the voting
stock of ISP outstanding on such date. If a change of control as described in
the ISP Credit Agreement occurs, the revolving credit facilities could be
terminated and the loans thereunder accelerated, an event which could also cause
the $200 million principal amount of 9% Senior Notes due 1999 of ISP (the 'ISP
Notes') to be accelerated. See 'Capitalization.' In addition, each Indenture
requires the Company, in the event of a Change of Control (as defined), to make
an offer to purchase the New Notes issued pursuant thereto at a purchase price
of 101% of the principal amount of such New Notes (or, if lower, the applicable
redemption prices then in effect under the provisions described in the first and
fourth paragraphs under 'Description of the New Notes--Optional Redemption'). A
change of control under the ISP Credit Agreement or under the Indentures would
have a material adverse impact on ISP and ISP Holdings, and there can be no
assurance that the Company will have the financial resources necessary to repay
or repurchase, as applicable, the loans under the ISP Credit Agreement, the ISP
Notes or the Notes upon such an event. Samuel J. Heyman, Chairman and Chief
Executive Officer of GAF, ISP Holdings, G-I Holdings, ISP and BMCA, beneficially
owns approximately 83% of the issued and outstanding ISP Common Stock. Based on
publicly available information, ISP Holdings believes that no unrelated third
party beneficially owns 5% or more of the issued and outstanding ISP Common
Stock.
    
 
                                       17
<PAGE>
HOLDING COMPANY STRUCTURE AND RELATED CONSIDERATIONS
 
     ISP Holdings is a holding company with no business operations of its own.
ISP Holdings' principal sources of funds to pay interest and principal with
respect to the Notes, to redeem or repurchase Notes upon the occurrence of a
Change of Control or otherwise and to pay its other obligations, will be,
principally, dividends and loans from ISP, payments pursuant to the ISP Holdings
Tax Sharing Agreement, borrowings, refinancing of indebtedness or capital
contributions or loans from its affiliates or stockholders. None of the
affiliates or stockholders of ISP Holdings, including ISP, will be required to
make any capital contributions or other payments to ISP Holdings with respect to
ISP Holdings' obligations on the Notes or any of its other obligations, and the
obligations of ISP Holdings with respect to the Notes will not be guaranteed by
any affiliate of ISP Holdings or any other person. There can be no assurance
that any of the foregoing actions could be effected on satisfactory terms, that
they would be sufficient to enable ISP Holdings to make any payments in respect
of the Notes when required or that any of such actions would be permitted by the
terms of debt or other instruments of the affiliates or stockholders of ISP
Holdings then in effect.
 
     The ISP Credit Agreement and the indenture governing the ISP Notes contain
restrictions on payments, including loans and advances, from ISP and its
subsidiaries to its parent corporations. Such restrictions limit the
availability of dividends and other payments from ISP, which would provide cash
to ISP Holdings to service its obligations, including interest on the Notes. In
addition, the ISP Credit Agreement limits ISP from making loans to, or providing
letters of credit for the benefit of, affiliates, including ISP Holdings, in

excess of $75 million outstanding at any time. As of September 29, 1996, after
giving effect to the most restrictive of the aforementioned restrictions, it
would have been permissible for ISP to pay dividends in the aggregate amount of
$79.9 million, of which $66.4 million would have been available to ISP Holdings,
and to make loans to affiliates of $72.7 million. See 'Management's Discussion
and Analysis of Financial Condition and Results of Operations--Liquidity and
Financial Condition' and Note 8 of Notes to Consolidated Financial Statements.
 
     The events that will constitute a Change of Control under the Indentures
may also constitute events of default or repurchase right events under certain
debt instruments of ISP and its subsidiaries. See '--Change of Control;
Acceleration of Debt.' In addition, if ISP Holdings owns less than 80% of ISP
Common Stock, payments pursuant to the ISP Holdings Tax Sharing Agreement would
not be available to ISP Holdings. See 'Tax Sharing Agreement.'
 
     Any right of ISP Holdings and its creditors, including holders of the
Notes, to participate in the assets of any of ISP Holdings' subsidiaries upon
any liquidation or reorganization of any such subsidiary will be subject to the
prior claims of that subsidiary's creditors, including trade creditors (except
to the extent ISP Holdings may itself be a creditor of such subsidiary).
Accordingly, the Notes will be effectively subordinated to all liabilities of
ISP Holdings' subsidiaries, including trade payables.
 
   
RESTRICTIONS IMPOSED BY INDEBTEDNESS
    
 
   
     The terms of the Indentures and the ISP Credit Agreement contain a number
of significant covenants that, among other things, restrict the ability of the
Company and its subsidiaries to dispose of assets or merge, incur debt, pay
dividends, repurchase or redeem capital stock and indebtedness, create liens,
make capital expenditures and make certain investments or acquisitions. The
ability of the Company and its subsidiaries to comply with such provisions may
be affected by events beyond the Company's control. In the event of any such
default under the ISP Credit Agreement, depending on the actions taken by the
lenders party to the ISP Credit Agreement (the 'Lenders'), the Lenders could
elect to declare all amounts borrowed under the ISP Credit Agreement, together
with accrued interest and other fees, to be due and payable, require ISP to
apply all its available cash to repay such borrowings and prevent ISP from
making distributions to the Company including distributions that could be used
to make payments on the Notes. If the indebtedness under the ISP Credit
Agreement were to be accelerated, there can be no assurance that the assets of
ISP would be sufficient to repay all indebtedness of ISP in full. In addition,
certain defaults under the ISP Credit Agreement will result in a default under
the Indentures. See 'Description of the New Notes--Events of Default.'
    
 
                                       18
<PAGE>
ACETYLENE SUPPLY
 
     The primary raw material used by ISP in the manufacture of its specialty
chemicals is acetylene. Acetylene is available from a limited number of

suppliers and, because of its instability, can only be transported short
distances. Acetylene is obtained by ISP for domestic use from two unaffiliated
suppliers, each using a different production technology, pursuant to long-term
supply contracts. In the event of a substantial interruption in the supply of
acetylene from current sources, no assurances can be made that ISP would be able
to obtain as much acetylene from other sources as would be necessary to meet its
supply requirements. A substantial interruption of ISP's supply of acetylene
would have a material adverse effect on the business and operations of the
Company as approximately 85-90% of the sales of ISP's specialty chemicals are
derived from acetylene which is either purchased in the United States as a raw
material or is purchased in the form of butanediol from GAF-Huls Chemie GmbH, a
joint venture between Huls AG and ISP ('GAF-Huls'). ISP has a long-standing
agreement with GAF-Huls to import butanediol into the United States for use as a
feedstock for the production of ISP's solvents and polymers. ISP has not
experienced an interruption of its acetylene supply that has had a material
adverse effect on its sales of specialty chemicals. See
'Business--ISP--Specialty Chemicals--Raw Materials.'
 
FOREIGN CURRENCY FLUCTUATIONS
 
     Approximately 50% of the Company's net sales and 54% of its operating
income in 1995 was attributable to its international operations. Fluctuations in
the value of foreign currencies may cause the Company's U.S. dollar denominated
sales and profits to decrease or increase without relation to the actual sales
or profits of its international operations. For a discussion of the Company's
international operations, see 'Business--ISP-- Specialty
Chemicals--International Operations,' and for a discussion of the Company's
policy to manage its foreign currency exposure, see 'Management's Discussion and
Analysis of Financial Condition and Results of Operations--Liquidity and
Financial Condition.'
 
SALES TO SIGNIFICANT CUSTOMERS
 
   
     In 1996, BMCA and USI purchased approximately $50.5 million of mineral
products from ISP, representing approximately 7% of ISP's total net sales and
approximately 59% of ISP's net sales of mineral products. No other customer
accounted for more than 5% of ISP's total net sales in 1996. BMCA purchases from
ISP all of its colored roofing granule requirements (except for the requirements
of BMCA's California roofing plant) under a requirements contract which was
renewed for 1997 and is subject to annual renewal unless terminated by ISP or
BMCA. In December 1995, USI commenced purchasing from ISP substantially all of
its requirements for colored roofing granules (except for the requirements of
USI's Stockton, California and Corvallis, Oregon plants) pursuant to a
requirements contract which expires December 31, 1997. The consummation of the
Spin Off Transactions, which resulted in BMCA and USI no longer being
subsidiaries of ISP Holdings, did not affect the terms of such requirements
contracts. A substantial decrease in business from BMCA would have an adverse
impact on ISP's financial condition and results of operations.
    
 
REGULATION; ENVIRONMENTAL CONSIDERATIONS
 
     The Company, together with other companies, is a party to a variety of

proceedings and lawsuits involving environmental matters ('Environmental
Claims') under the Comprehensive Environmental Response Compensation and
Liability Act ('CERCLA') and similar state laws, in which recovery is sought for
the cost of cleanup of contaminated sites, a number of which are in the early
stages or have been dormant for protracted periods.
 
     For additional information relating to environmental litigation involving
the Company, see 'Business-- Environmental Litigation.'
 
     The enactment by federal, state or local governments of new laws or
regulations or a change in the interpretation of existing laws or regulations
relating to environmental matters could increase the cost of producing the
products manufactured by the Company or otherwise adversely affect the demand
for its products and may require additional expenditures. See
'Business--Environmental Compliance.'
 
                                       19
<PAGE>
CONTROLLING STOCKHOLDER
 
     ISP Holdings is controlled by Samuel J. Heyman, Chairman and Chief
Executive Officer of GAF, ISP Holdings, G-I Holdings, ISP and BMCA. Accordingly,
Mr. Heyman has the ability to elect the entire Board of Directors of each of
such companies and determine the outcome of any other matter submitted to their
respective stockholders for approval. In particular, subject to the terms of the
Indentures, Mr. Heyman has the ability to effect certain corporate transactions,
including mergers, consolidations and the sale of all or substantially all of
ISP Holdings' or its subsidiaries' assets. See 'Security Ownership of Certain
Beneficial Owners and Management' and 'Risk Factors--Change of Control;
Acceleration of Debt.'
 
ADDITIONAL RISKS RELATED TO THE SPIN OFF TRANSACTIONS
 
   
     If a court in a lawsuit by an unpaid creditor or a representative of
creditors, such as a trustee in bankruptcy, were to find that prior to or
immediately after the Spin Off Transactions were effected, GAF, ISP Holdings, G
Industries, GFC or G-I Holdings was insolvent, engaged in a business or
transaction for which such entity's remaining assets constituted unreasonably
small capital, intended to incur, or believed it would incur, debts beyond its
ability to pay as such debts matured or if such company was found to be at the
time of the consummation of the Spin Off Transactions, a defendant in civil
actions (including those asserting asbestos-related claims) that resulted in
judgments which such company was or became unable to satisfy, such court may be
asked to void the Spin Off Transactions (in whole or in part) as a fraudulent
conveyance and require that, among other things, the stockholders that received
a distribution return the distribution, including the common stock of ISP
Holdings (in whole or in part), to the distributing company. In such event, the
assets of GAF distributed in the Spin Off Transactions, including the capital
stock of ISP Holdings and ISP, could be subject to claims of such creditors,
including asbestos claimants. The measure of insolvency for purposes of the
foregoing will vary depending upon the jurisdiction whose law is being applied.
Generally, however, GAF, ISP Holdings, G Industries, GFC or G-I Holdings would
be considered insolvent if the fair value of their respective assets were less

than the amount of their respective liabilities or if they incurred debt beyond
their ability to repay such debt as it matures. In addition, under Section 170
of the Delaware General Corporation Law (which is applicable to all corporations
that made a distribution as part of the Spin Off Transactions) a corporation
generally may make distributions to its stockholders only out of its surplus
(net assets minus capital) and not out of capital and in the event that all or
part of the Spin Off Transactions were found unlawful under Section 170, such
distributions may be recaptured for the benefit of creditors.
    
 
   
     As a condition to the consummation of the Spin Off Transactions, the Board
of Directors of GAF, ISP Holdings, GFC, G-I Holdings and G Industries received a
satisfactory opinion from HLHZ regarding the solvency of such companies and the
satisfaction of certain standards regarding the permissibility of certain
distributions contemplated by the Spin Off Transactions under Section 170 of the
Delaware General Corporation Law. HLHZ rendered such an opinion to the Boards of
Directors of each of such companies on the date of the distribution of the
capital stock of ISP Holdings to GAF's stockholders. See 'The Spin Off
Transactions.' There is no certainty, however, that a court would reach the same
conclusions set forth in such opinion in determining whether GAF, ISP Holdings,
GFC, G-I Holdings or G Industries was insolvent at the time of, or after giving
effect to, the Spin Off Transactions. See 'The Spin Off Transactions' for a
description of the reviews, analyses and inquiries made by HLHZ and the
financial projections, forecasts and other representations provided by GAF and
relied upon by HLHZ in rendering such opinion.
    
 
     In November 1996, GAF received the IRS Ruling to the effect that the Spin
Off Transactions will not result in recognition of income by any members of the
GAF Tax Group. The IRS Ruling was conditioned upon the accuracy of certain
representations contained in GAF's request therefor as to certain facts and
circumstances with respect to the Spin Off Transactions. If the Spin Off
Transactions did not qualify as 'tax-free spin offs' under the Internal Revenue
Code, the GAF Tax Group would recognize gain, but not loss, as if the common
stock of ISP Holdings, G-I Holdings and ISP were sold at the fair market value
thereof. The gain recognized will be an amount equal to the fair market value of
the ISP Holdings common stock, G-I Holdings common stock and ISP Common Stock in
excess of the adjusted tax basis in such shares of common stock as determined
immediately prior to the Spin Off Transactions. The tax on the income would be
payable by GAF. To the extent not paid by GAF, each member of the GAF Tax Group
as it existed prior to the Spin Off Transactions (including ISP
 
                                       20
<PAGE>
Holdings, ISP and their respective subsidiaries) would be jointly and severally
liable for such tax liability. See 'Certain Relationships--Mutual
Indemnification.'
 
     As a matter of federal tax law, ISP Holdings, ISP and their subsidiaries
would be jointly and severally liable for any tax liability for any year in
which they were members of the GAF Tax Group. GAF, G-I Holdings, G Industries
and GCC have agreed to indemnify ISP Holdings, ISP and their subsidiaries for
all tax liabilities of the indemnifying companies, including any liability with

respect to the Spin Off Transactions. See 'Tax Sharing Agreement.'
 
ABSENCE OF A PUBLIC MARKET
 
     Prior to the exchange of the New Notes offered hereby, there has been no
public market for any of the Notes, and there can be no assurance as to (i) the
liquidity of any such market that may develop, (ii) the ability of the holders
of New Notes to sell their New Notes or (iii) the price at which the holders of
New Notes would be able to sell their New Notes. If such a market were to exist,
the New Notes could trade at prices that may be higher or lower than their
principal amount or purchase price, depending on many factors, including
prevailing interest rates, the market for similar notes, and the financial
performance of ISP Holdings and its subsidiaries. ISP Holdings does not intend
to list the New 9% Notes or the New 9 3/4% Notes on any securities exchange or
to seek approval for quotations through any automated quotation system and no
active market for the New Notes is currently anticipated. There is no assurance
as to the liquidity of the trading market for the New Notes. Bear, Stearns & Co.
Inc. has advised ISP Holdings that it currently anticipates making a secondary
market for the New Notes, but is not obligated to do so and any such market
making, if commenced, may be discontinued at any time without notice.
 
EXCHANGE OFFER PROCEDURES
 
     Issuance of the New 9% Notes in exchange for Old 9% Notes and New 9 3/4%
Notes in exchange for Old 9 3/4% Notes pursuant to the Exchange Offers will be
made only after a timely receipt by the Exchange Agent of certificates for such
Old Notes or a timely Book-Entry Confirmation (as defined) of such Old Notes
into the Exchange Agent's account at the Book-Entry Transfer Facility, a
properly completed and duly executed Letter of Transmittal and all other
required documents. All questions as to the validity, form, eligibility
(including time of receipt) and acceptance of Old Notes tendered for exchange
will be determined by ISP Holdings in its sole discretion, which determination
will be final and binding on all parties. Therefore, holders of each issue of
Old Notes desiring to tender such Old Notes in exchange for the applicable issue
of New Notes should allow sufficient time to ensure timely delivery. Old Notes
that are not tendered or are tendered but not accepted will, following the
consummation of the Exchange Offers, continue to be subject to the existing
restrictions upon transfer thereof and ISP Holdings will have no further
obligation to provide for the registration under the Securities Act of such Old
Notes except as described herein. See 'The Exchange Offers--Purpose and Effect.'
In addition, any holder of Old Notes who tenders in the applicable Exchange
Offer for the purpose of participating in a distribution of the applicable New
Notes will be required to comply with the registration and prospectus delivery
requirements of the Securities Act in connection with any resale transaction.
Each broker-dealer that receives New Notes for its own account in exchange for
Old Notes, where such Old Notes were acquired by such broker-dealer as a result
of market-making activities or other trading activities, must acknowledge that
it will deliver a prospectus in connection with any resale of such New Notes.
See 'Plan of Distribution.' To the extent that Old Notes are tendered and
accepted in either Exchange Offer, the trading market for untendered and
tendered but unaccepted Old Notes could be adversely affected. ISP Holdings does
not intend to extend either Exchange Offer although it reserves the right to do
so. See 'The Exchange Offers.'
 

                                       21



<PAGE>
                                 CAPITALIZATION
 
     The following table sets forth the consolidated capitalization of ISP
Holdings as of September 29, 1996 and as adjusted on a pro forma basis to give
effect to the Transactions. This table should be read in conjunction with the
Consolidated Financial Statements and related notes included elsewhere in this
Prospectus.
 
<TABLE>
<CAPTION>
                                                                                          AS OF SEPTEMBER 29, 1996
                                                                                         ---------------------------
                                                                                           ACTUAL       PRO FORMA(1)
                                                                                         -----------    ------------
                                                                                                 (THOUSANDS)
<S>                                                                                      <C>            <C>
Short-term Debt and current maturities of Long-term Debt:
  Current maturities of long-term debt................................................    $     361       $    361
  Loan payable to affiliate...........................................................       17,797             --
  Short-term debt.....................................................................       22,518         22,518
                                                                                         -----------    ------------
     Total............................................................................    $  40,676       $ 22,879
                                                                                         -----------    ------------
                                                                                         -----------    ------------
 
Long-term Debt (excluding current maturities): (2)
  9% Senior Notes due 2003............................................................    $      --       $324,093
  9 3/4% Senior Notes due 2002........................................................           --        199,871
  9% ISP Senior Notes Due 1999........................................................      200,000        200,000
  Borrowings under revolving credit facilities........................................           --         25,577(3)
  Obligations on mortgaged properties.................................................       38,125         38,125
  Obligations under capital leases....................................................        1,635          1,635
  Long-term note payable to affiliate.................................................       80,977             --
                                                                                         -----------    ------------
     Total Long-term Debt.............................................................    $ 320,737       $789,301
                                                                                         -----------    ------------
                                                                                         -----------    ------------
Shareholder's Equity (Deficit):
  Capital stock and additional paid-in capital........................................    $ 118,516       $244,780
  Excess of purchase price over adjusted historical cost of the predecessor company
     shares owned by GAF stockholders.................................................      (72,605)       (63,483)
  Retained earnings...................................................................        1,924          1,924
  Cumulative translation adjustment and other.........................................       13,818         13,211
                                                                                         -----------    ------------
     Total Shareholder's Equity.......................................................    $  61,653       $196,432
                                                                                         -----------    ------------
                                                                                         -----------    ------------
  Total Capitalization................................................................    $ 382,390       $985,733
                                                                                         -----------    ------------
                                                                                         -----------    ------------
</TABLE>
 

- ------------------
(1) For an explanation of the assumptions used to arrive at such pro forma
    information, see 'Notes to Selected Financial Data.'
 
(2) For a description of long-term debt, see Note 8 to Consolidated Financial
    Statements.
 
(3) Reflects borrowings of $25.6 million under the ISP Credit Agreement used to
    repay loans owed by ISP to G-I Holdings as of September 29, 1996.
 
                                       22
<PAGE>
                            SELECTED FINANCIAL DATA
 
     Set forth below are selected consolidated financial data of the Company. A
predecessor company to GAF was acquired on March 29, 1989 in a management-led
buyout (the 'GAF Acquisition'). Accordingly, a step up in asset values to fair
value was required by the purchase method of accounting. As a result, financial
data for periods subsequent to the GAF Acquisition reflect non-cash charges
consisting of goodwill amortization and depreciation of increased asset values.
Such non-cash charges amounted to $22, $22, $22.6, $22.6, $22.5, $16.8 and $16.8
million for the years 1991, 1992, 1993, 1994 and 1995 and the first nine months
of 1995 and 1996, respectively. The results of any interim period are not
necessarily indicative of the results to be expected for the full year.
 
   
     The pro forma balance sheet data give effect to the Transactions as if they
had been completed as of September 29, 1996. The pro forma operating data give
effect to the Transactions as if they had been completed as of January 1, 1995.
The Exchange Offers will not affect the amount of the Company's long-term debt
or stockholder's equity. The pro forma financial information does not purport to
project the financial position or the results of operations for any future
period or to represent what the financial position or results of operations
would have been if the Transactions had been completed at the dates indicated.
All financial data relating to ISP Holdings and its subsidiaries contained
herein have been prepared to retroactively reflect the formation of ISP
Holdings. See Notes 14 and 16 to Consolidated Financial Statements.
    
 
<TABLE>
<CAPTION>
                                                                                                NINE MONTHS ENDED
                                                                                             ------------------------
                                                            YEAR ENDED DECEMBER 31,            OCT. 1,     SEPT. 29,
                                                     --------------------------------------     1995         1996
                                                      1991    1992    1993    1994    1995   (UNAUDITED)  (UNAUDITED)
                                                     ------  ------  ------  ------  ------  -----------  -----------
                                                                     (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                                  <C>     <C>     <C>     <C>     <C>     <C>          <C>
Operating Data:
  Net sales......................................... $525.8  $570.8  $548.3  $600.0  $689.0    $ 530.3      $ 544.1
  Operating income..................................  121.9   107.7    65.1    99.2   127.1       99.2        105.7
  Interest expense..................................   52.7    30.6    24.5    28.7    33.1       24.8         21.9
  Income from continuing operations before income

     taxes and extraordinary items..................   75.7    85.8    49.8    72.5   106.1       81.2         98.2
  Income from continuing operations before
     extraordinary items and cumulative
     effect of accounting change....................   46.2    47.5    23.8    37.1    55.1       41.8         51.8
  Ratio of earnings to fixed charges(1).............   2.48    3.78    2.83    3.32    4.06       4.08         5.23
</TABLE>
 
<TABLE>
<CAPTION>
                                                                                                  SEPTEMBER 29, 1996
                                                                                        --------------------------------------
                                                     DECEMBER 31,                                     PRO FORMA (GIVING EFFECT
                                 ----------------------------------------------------     ACTUAL        TO THE TRANSACTIONS)
                                   1991       1992       1993       1994       1995     (UNAUDITED)         (UNAUDITED)
                                 --------   --------   --------   --------   --------   -----------   ------------------------
                                                               (IN MILLIONS, EXCEPT RATIO DATA)
<S>                              <C>        <C>        <C>        <C>        <C>        <C>           <C>
Balance Sheet Data:
  Cash and short-term
    investments................  $   10.1   $   81.7   $   82.8   $   77.4   $  150.0    $   111.7            $  156.7
  Total working capital........     178.6      257.1      143.9      228.0      290.0        413.0               220.9
  Total assets.................   1,235.0    1,348.2    1,309.0    1,357.5    1,460.4      1,537.3             1,361.1
  Long-term debt less current
    maturities(2)..............     131.4      493.0      367.7      285.4      280.3        239.8               789.3
  Stockholder's equity
    (deficit)..................     156.2      (42.6)     (42.6)     (15.8)      (1.7)        61.7               196.4
</TABLE>
 
                                       23
<PAGE>
 
   
<TABLE>
<CAPTION>
                                                                                                       NINE MONTHS ENDED
                                                        YEAR ENDED DECEMBER 31,                  -----------------------------
                                          ----------------------------------------------------   OCT. 1, 1995   SEPT. 29, 1996
                                            1991       1992       1993       1994       1995     (UNAUDITED)     (UNAUDITED)
                                          --------   --------   --------   --------   --------   ------------   --------------
                                                                    (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                       <C>        <C>        <C>        <C>        <C>        <C>            <C>
Other Data:
  Depreciation..........................  $   23.2   $   25.6   $   28.7   $   32.8   $   36.0     $   26.7        $   28.2
  Goodwill amortization.................      13.8       13.7       13.9       13.4       13.2          9.9             9.9
  Capital expenditures and
    acquisitions........................      34.4       70.5       62.9       31.1       38.9         26.6            35.7
  Cash Flows from:
    Operating activities................      47.1       77.3      111.8       75.9      143.8         97.7            82.5
    Investing activities................     (34.4)     (70.5)     (61.7)     (27.2)    (124.4)       (98.0)            5.0
    Financing activities................     (21.9)      64.8      (50.3)     (39.6)     (25.5)        (9.4)          (89.8)
  Adjusted EBITDA(3)....................     207.3      207.2      167.5      225.8      245.6        190.7           219.8
  Ratio of Adjusted EBITDA to Adjusted
    Interest Expense(3).................      2.14       2.95       2.32       2.36       2.16         2.27            2.47
</TABLE>

    
 
<TABLE>
<CAPTION>
                                                                                                NINE MONTHS ENDED
                                                                                            --------------------------
                                                                          YEAR ENDED          OCT. 1,       SEPT. 29,
                                                                       DECEMBER 31, 1995       1995           1996
                                                                          (UNAUDITED)       (UNAUDITED)    (UNAUDITED)
                                                                       -----------------    -----------    -----------
                                                                              (IN MILLIONS, EXCEPT RATIO DATA)
<S>                                                                    <C>                  <C>            <C>
Pro Forma Operating Data(4):
  Interest expense..................................................         $78.8             $59.1          $56.2
  Income from continuing operations.................................          25.3              19.5           29.4
  Ratio of earnings to fixed charges(1).............................          1.79              1.80           2.16
  Ratio of Adjusted EBITDA to Adjusted Interest Expense(3)..........          2.32              2.37           2.83
</TABLE>
 
- ------------------
(1) For purposes of these computations, earning consist of income (loss) from
    continuing operations before income taxes, minority interest, extraordinary
    items and cumulative effect of accounting change, plus fixed charges. Fixed
    charges consist of interest on indebtedness (including amortization of debt
    issuance costs) plus that portion of lease rental expense representative of
    interest (estimated to be one-third of lease rental expense).
 
(2) See 'Capitalization' and Note 8 to Consolidated Financial Statements.
 
   
(3) The Adjusted EBITDA data are being presented because such data relate to
    debt covenants under the Indentures. The calculation of the ratio of
    Adjusted EBITDA to Adjusted Interest Expense has been performed in
    accordance with the definitions in the Indentures. See 'Description of the
    New Notes.' Accordingly, Adjusted EBITDA is calculated as income from
    continuing operations before income taxes, plus income (loss) from
    discontinued operations before income taxes, less extraordinary items,
    increased by interest expense, depreciation and goodwill amortization and
    excluding equity in earnings of the GAF-Huls joint venture and Surfactants
    Partnership income except to the extent distributed in cash. Adjusted
    Interest Expense is calculated as total interest expense excluding interest
    expense on non-recourse debt related to the Surfactants Partnership. Certain
    restrictions exist as to the amounts available for making loans, paying
    dividends and otherwise making distributions to ISP Holdings. See 'Risk
    Factors--Holding Company Structure and Related Considerations.' See 'Summary
    Financial Data' for the details of the calculations of Adjusted EBITDA and
    Adjusted Interest Expense. As an indicator of the Company's operating
    performance, such supplemental financial information should not be
    considered as an alternative to net income or any other measure of
    performance under generally accepted accounting principles.
    
 
   
(4) The Pro Forma Operating Data have been prepared assuming that the ISP

    Holdings Transactions and the Spin Off Transactions were consummated as of
    the beginning of the respective periods presented. The effect of such
    assumptions was to decrease the Company's pro forma income from continuing
    operations before income taxes by $45.7, $34.3 and $34.3 million for the
    year 1995 and the first nine months of 1995 and 1996, respectively. As a
    result, the Company's pro forma provision for income taxes decreased by $16,
    $12 and $12 million for the year 1995 and the first nine months of 1995 and
    1996, respectively, based on an effective marginal income tax rate of 35%.
    See 'Pro Forma Consolidated Financial Statements.'
    
 
                                       24

<PAGE>
   
                               ISP HOLDINGS INC.
                  PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS
                                  (UNAUDITED)
    
 
   
     The following unaudited pro forma consolidated financial statements have
been prepared on the basis as set forth in the notes hereto.
    
 
   
     The accompanying pro forma consolidated balance sheet gives effect to such
transactions as if they had been completed as of September 29, 1996. The
accompanying pro forma consolidated income statements give effect to such
transactions as if they had been completed as of January 1, 1995.
    
 
   
     The pro forma consolidated financial statements do not purport to project
the results of operations for any future period or to represent what the
financial position or results of operations would have been if the Transactions
had been completed at the dates indicated. All financial data relating to ISP
Holdings and its subsidiaries contained herein have been prepared to
retroactively reflect the formation of ISP Holdings.
    
 
                                       25


<PAGE>
   
                               ISP HOLDINGS INC.
                      PRO FORMA CONSOLIDATED BALANCE SHEET
                            AS OF SEPTEMBER 29, 1996
                                  (THOUSANDS)
                                  (UNAUDITED)
    
 
   
<TABLE>
<CAPTION>
                                                                                 ADJUSTMENTS
                                                                        ------------------------------
                                                                            ISP                                PRO FORMA
                                                                          HOLDINGS          SPIN OFF            (AFTER
                                                            ACTUAL      TRANSACTIONS      TRANSACTIONS       TRANSACTIONS)
                                                          ----------    ------------      ------------       -------------
<S>                                                       <C>           <C>               <C>                <C>
                        ASSETS
Current assets:
  Cash.................................................   $   11,767     $  315,172(1)     $   25,577(5)      $    56,767
                                                                           (373,944)(2)       (98,774) (6)
                                                                            131,969(4)         45,000(7)
  Short-term investments...............................       99,952                                               99,952
  Accounts receivable, trade...........................       72,764                                               72,764
  Accounts receivable, other...........................       18,824                                               18,824
  Insurance receivable.................................        1,813                                                1,813
  Inventories..........................................       98,354                                               98,354
  Deferred income tax benefits.........................        6,596                           18,495(9)           25,091
  Net current assets of discontinued operations........      254,979                         (254,979)(11)             --
  Other current assets.................................        7,130                                                7,130
                                                          ----------    ------------      ------------       -------------
    Total current assets...............................      572,179         73,197          (264,681)            380,695
Investment in G-I Holdings Notes.......................           --        373,944(2)        (45,000) (7)             --
                                                                            199,871(3)       (396,846) (8)
                                                                           (131,969)(4)
Property, plant and equipment..........................      482,416                            3,143(10)         485,559
Goodwill, net..........................................      420,558                            3,190(10)         423,748
Insurance receivable...................................        5,130                                                5,130
Other assets...........................................       57,005          8,921(1)                             65,926
                                                          ----------    ------------      ------------       -------------
Total assets...........................................   $1,537,288     $  523,964        $ (700,194)        $ 1,361,058
                                                          ----------    ------------      ------------       -------------
                                                          ----------    ------------      ------------       -------------
         LIABILITIES AND SHAREHOLDER'S EQUITY
Current liabilities:
  Short-term debt......................................   $   22,518                                          $    22,518
  Current maturities of long-term debt.................          361                                                  361
  Loan payable to affiliate............................       17,797                       $  (17,797) (6)             --
  Accounts payable.....................................       50,017                                               50,017
  Accrued liabilities..................................       57,929                                               57,929
  Due to affiliate.....................................        4,413                           18,495(9)           22,908
  Income taxes.........................................        6,099                                                6,099

                                                          ----------    ------------      ------------       -------------
    Total current liabilities..........................      159,134                              698             159,832
Long-term debt less current maturities.................      239,760     $  324,093(1)         25,577(5)          789,301
                                                                            199,871(3)
Long-term note payable to affiliate....................       80,977                          (80,977) (6)             --
Deferred income taxes..................................       45,452                          (10,000) (9)         35,452
Net noncurrent liabilities of discontinued
  operations...........................................      770,271                         (770,271)(11)             --
Other liabilities......................................       62,224                                               62,224
Minority interest in ISP...............................      117,817                                              117,817
Shareholder's equity:
Common stock and additional paid-in capital............      118,516                         (396,846) (8)        244,780
                                                                                               10,000(9)
                                                                                                6,333(10)
                                                                                              506,777(11)
Excess of purchase price over the adjusted historical
  cost of the predecessor company shares owned by GAF's
  stockholders.........................................      (72,605)                           9,122(11)         (63,483)
Retained earnings......................................        1,924                                                1,924
Cumulative translation adjustment and other............       13,818                             (607)(11)         13,211
                                                          ----------    ------------      ------------       -------------
  Shareholder's equity.................................       61,653             --           134,779             196,432
                                                          ----------    ------------      ------------       -------------
Total liabilities and shareholder's equity.............   $1,537,288     $  523,964        $ (700,194)        $ 1,361,058
                                                          ----------    ------------      ------------       -------------
                                                          ----------    ------------      ------------       -------------
</TABLE>
    
 
   
     See accompanying Notes to Pro Forma Consolidated Financial Statements.
    
 
                                       26

<PAGE>
   
                               ISP HOLDINGS INC.
                    PRO FORMA CONSOLIDATED INCOME STATEMENT
                      FOR THE YEAR ENDED DECEMBER 31, 1995
                                  (THOUSANDS)
                                  (UNAUDITED)
    
 
   
<TABLE>
<CAPTION>
                                                                                  ADJUSTMENTS
                                                                          ----------------------------
                                                                              ISP                          PRO FORMA
                                                                            HOLDINGS        SPIN OFF        (AFTER
                                                               ACTUAL     TRANSACTIONS    TRANSACTIONS   TRANSACTIONS)
                                                              --------    ------------    ------------   -------------
<S>                                                           <C>         <C>             <C>            <C>
Net sales..................................................   $689,002                                     $ 689,002
                                                              --------    ------------    ------------   -------------
Costs and expenses:
  Cost of products sold....................................    414,672                                       414,672
  Selling, general and administrative......................    134,011                                       134,011
  Goodwill amortization....................................     13,223                                        13,223
                                                              --------    ------------    ------------   -------------
     Total costs and expenses..............................    561,906                                       561,906
                                                              --------    ------------    ------------   -------------
Operating income...........................................    127,096                                       127,096
Interest expense...........................................    (33,091)     $(30,654)(12)   $  4,392(14)     (78,840)
                                                                             (19,487)(13)
Equity in earnings of joint venture........................      5,413                                         5,413
Other income, net..........................................      6,684                                         6,684
                                                              --------    ------------    ------------   -------------
Income from continuing operations before income taxes......    106,102       (50,141)          4,392          60,353
Income taxes...............................................    (38,727)       10,729(12)      (1,537)(14)     (22,714)
                                                                               6,821(13)
Minority interest in income of ISP.........................    (12,306)                                      (12,306)
                                                              --------    ------------    ------------   -------------
Income from continuing operations..........................   $ 55,069      $(32,591)       $  2,855       $  25,333
                                                              --------    ------------    ------------   -------------
                                                              --------    ------------    ------------   -------------
</TABLE>
    
 
   
     See accompanying Notes to Pro Forma Consolidated Financial Statements.
    
 
                                       27

<PAGE>
   
                               ISP HOLDINGS INC.
                    PRO FORMA CONSOLIDATED INCOME STATEMENT
                  FOR THE NINE MONTHS ENDED SEPTEMBER 29, 1996
                                  (THOUSANDS)
                                  (UNAUDITED)
    
 
   
<TABLE>
<CAPTION>
                                                                              ADJUSTMENTS
                                                                     ------------------------------        PRO FORMA
                                                                     ISP HOLDINGS        SPIN OFF           (AFTER
                                                        ACTUAL       TRANSACTIONS      TRANSACTIONS      TRANSACTIONS)
                                                       --------      ------------      ------------      -------------
<S>                                                    <C>           <C>               <C>               <C>
Net sales...........................................   $544,135                                            $ 544,135
                                                       --------      ------------      ------------      -------------
Costs and expenses:
  Cost of products sold.............................    320,295                                              320,295
  Selling, general and administrative...............    108,236                                              108,236
  Goodwill amortization.............................      9,900                                                9,900
                                                       --------      ------------      ------------      -------------
     Total costs and expenses.......................    438,431                                              438,431
                                                       --------      ------------      ------------      -------------
Operating income....................................    105,704                                              105,704
Interest expense....................................    (21,879)       $(22,991)(12)     $  3,294(14)        (56,192)
                                                                        (14,616)(13)
Equity in earnings of joint venture.................      4,948                                                4,948
Other income, net...................................      9,429                                                9,429
                                                       --------      ------------      ------------      -------------
Income from continuing operations before
  income taxes and extraordinary items..............     98,202         (37,607)            3,294             63,889
Income taxes........................................    (35,647)          8,047(12)        (1,153)(14)       (23,638)
                                                                          5,115(13)
Minority interest in income of ISP..................    (10,802)                                             (10,802)
                                                       --------      ------------      ------------      -------------
Income from continuing operations before
  extraordinary items...............................   $ 51,753        $(24,445)         $  2,141          $  29,449
                                                       --------      ------------      ------------      -------------
                                                       --------      ------------      ------------      -------------
</TABLE>
    
 
   
     See accompanying Notes to Pro Forma Consolidated Financial Statements.
    
 
                                       28

<PAGE>
   
                               ISP HOLDINGS INC.
                    PRO FORMA CONSOLIDATED INCOME STATEMENT
                   FOR THE NINE MONTHS ENDED OCTOBER 1, 1995
                                  (THOUSANDS)
                                  (UNAUDITED)
    
 
   
<TABLE>
<CAPTION>
                                                                                  ADJUSTMENTS
                                                                         ------------------------------
                                                                              ISP                            PRO FORMA
                                                                           HOLDINGS         SPIN OFF          (AFTER
                                                               ACTUAL    TRANSACTIONS     TRANSACTIONS     TRANSACTIONS)
                                                              --------   -------------    -------------    -------------
 
<S>                                                           <C>        <C>              <C>              <C>
Net sales..................................................   $530,334                                       $ 530,334
                                                              --------   -------------    -------------    -------------
Costs and expenses:
  Cost of products sold....................................    322,329                                         322,329
  Selling, general and administrative......................     98,876                                          98,876
  Goodwill amortization....................................      9,922                                           9,922
                                                              --------                                     -------------
     Total costs and expenses..............................    431,127                                         431,127
                                                              --------                                     -------------
Operating income...........................................     99,207                                          99,207
Interest expense...........................................    (24,821)    $ (22,991)(12)    $ 3,294(14)       (59,134)
                                                                             (14,616)(13)
 
Equity in earnings of joint venture........................      2,950                                           2,950
Other income, net..........................................      3,869                                           3,869
                                                              --------   -------------    -------------    -------------
Income from continuing operations before income taxes......     81,205       (37,607)          3,294            46,892
Income taxes...............................................    (29,981)        8,047(12)      (1,153)(14)      (17,972)
                                                                               5,115(13)
Minority interest in income of ISP.........................     (9,452)                                         (9,452)
                                                              --------   -------------    -------------    -------------
 
Income from continuing operations..........................   $ 41,772     $ (24,445)        $ 2,141         $  19,468
                                                              --------   -------------    -------------    -------------
                                                              --------   -------------    -------------    -------------
</TABLE>
    
 
   
     See accompanying Notes to Pro Forma Consolidated Financial Statements.
    
 
                                       29

<PAGE>
   
                               ISP HOLDINGS INC.
              NOTES TO PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS
                                  (UNAUDITED)
 
     The following Notes to Pro Forma Consolidated Financial Statements should
be read in conjunction with descriptions of the Spin Off Transactions and ISP
Holdings Transactions included elsewhere in this Prospectus.
    
 
   
 (1) Reflects the issuance of $325 million in aggregate principal amount of the
     Old 9% Notes pursuant to the 9% Note Offering for net cash proceeds of
     $315.4 million, after related underwriting discount and deferred financing
     fees and expenses of the ISP Holdings Transactions of $8.9 million.
    
 
   
 (2) Reflects cash proceeds from the consummation of the Tender Offer in the
     amount of $373.9 million.
    
 
   
 (3) Reflects issuance of $199.9 million of the Old 9 3/4% Notes pursuant to the
     Old Exchange Offer.
    
 
   
 (4) Reflects the Repurchase by G-I Holdings from ISP Holdings of Discount Notes
     in an amount of $132 million.
    
 
   
 (5) Reflects borrowings by ISP of $25.6 million under the ISP Credit Agreement
     to be used to repay loans owed by ISP to G-I Holdings (see Note (6)).
    
 
   
 (6) Reflects repayment upon consummation of the Spin Off Transactions of $98.8
     million of loans owed by ISP to G-I Holdings.
    
 
   
 (7) Reflects the purchase by G-I Holdings from ISP Holdings of Discount Notes
     for an aggregate amount of $45 million pursuant to the Repurchase.
    
 
   
 (8) Reflects the capital contribution or sale by ISP Holdings to G-I Holdings
     of G-I Holdings' 10% Notes acquired in the Old Exchange Offer and of
     Discount Notes not sold to G-I Holdings pursuant to the Repurchase.
    
 

   
 (9) Adjustment related to foreign tax credit carryovers available to ISP and
     due to G-I Holdings under the ISP Tax Sharing Agreement. G-I Holdings
     intends to transfer the remaining amount not utilized in its 1996
     consolidated tax return, estimated to be approximately $10 million, to ISP
     Holdings.
    
 
   
(10) Reflects transfer of a purchase accounting adjustment from G-I Holdings to
     ISP Holdings relating to ISP's repurchases of its common stock.
    
 
   
(11) Reflects the spin off of discontinued operations (G-I Holdings, GFC, BMCA
     and USI) to GAF as a result of ISP Holdings distributing all of the
     outstanding capital stock of G-I Holdings to GAF.
    
 
   
(12) Reflects interest expense at a rate of 9% and amortization of deferred
     financing fees related to the Old 9% Notes, and the related tax effect at
     an assumed effective tax rate of 35.0%.
    
 
   
(13) Reflects interest expense at a rate of 9 3/4% on the $199.9 million of the
     Old 9 3/4% Notes and the related tax effect at an assumed effective tax
     rate of 35.0%.
    
 
   
(14) Reflects reduction of interest expense on the net debt reduction of $73.2
     million related to the repayment upon consummation of the Spin Off
     Transactions of loans owed by ISP to G-I Holdings (see Notes (5) and (6)
     above).
    
 
                                       30

<PAGE>
               MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
                      CONDITION AND RESULTS OF OPERATIONS
 
   
     Prior to January 1, 1997, ISP Holdings was a wholly owned subsidiary of
GAF. As of January 1, 1997, GAF effected the Spin Off Transactions that resulted
in, among other things, the capital stock of ISP Holdings (whose principal asset
is approximately 83.5% of the issued and outstanding capital stock of ISP) being
distributed to the stockholders of GAF. As a result of such distribution, ISP
Holdings and ISP are no longer direct or indirect subsidiaries of GAF, and the
Building Materials Business and the assets and liabilities of GFC are no longer
assets and liabilities of ISP Holdings. See 'The Spin Off Transactions.' As a
result of the Spin Off Transactions, ISP Holdings' continuing operations will be
conducted through its 83.5% owned subsidiary, ISP, which is engaged principally
in the manufacture and sale of specialty chemicals.
    
 
   
     Accordingly, the Building Materials Business and the assets and liabilities
of GFC, as well as the assets and liabilities of GAF Broadcasting Company, Inc.
(which was sold in August 1996) have been classified as 'Discontinued
Operations' within the financial statements for all periods presented. The
following discussion is on a continuing operations basis.
    
 
     The following discussion and analysis should be read in conjunction with
the Consolidated Financial Statements which appear elsewhere in this Prospectus.
As used herein, the term 'Company' refers to ISP Holdings and its consolidated
subsidiaries. All financial data contained herein have been prepared on a basis
which retroactively reflects the formation of ISP Holdings as discussed in the
consolidated financial statements.
 
     Set forth below are net sales and operating income for each of ISP
Holdings' business segments related to continuing operations for the years 1993,
1994 and 1995 and the first nine months of 1995 and 1996.
 
   
<TABLE>
<CAPTION>
                                                                                               NINE MONTHS ENDED
                                                            YEAR ENDED DECEMBER 31,      ------------------------------
                                                           --------------------------    OCT. 1, 1995    SEPT. 29, 1996
                                                            1993      1994      1995     (UNAUDITED)      (UNAUDITED)
                                                           ------    ------    ------    ------------    --------------
                                                                                  (IN MILLIONS)
<S>                                                        <C>       <C>       <C>       <C>             <C>
Net Sales:
  Specialty Chemicals...................................   $434.5    $482.4    $556.9       $432.8           $445.4
  Mineral Products......................................     81.3      81.1      86.1         67.3             65.5
  Other.................................................     32.5      36.5      46.0         30.2             33.2
                                                           ------    ------    ------    ------------       -------
     Total..............................................   $548.3    $600.0    $689.0       $530.3           $544.1
                                                           ------    ------    ------    ------------       -------

                                                           ------    ------    ------    ------------       -------
Operating Income:
  Specialty Chemicals...................................   $ 48.0    $ 79.9    $105.5       $ 81.4           $ 91.1
  Mineral Products......................................     16.6      14.6      16.3         14.0             12.9
  Other.................................................      0.5       4.7       5.3          3.8              1.7
                                                           ------    ------    ------    ------------       -------
     Total..............................................   $ 65.1    $ 99.2    $127.1       $ 99.2           $105.7
                                                           ------    ------    ------    ------------       -------
                                                           ------    ------    ------    ------------       -------
</TABLE>
    
 
   
     Note: Operating income in 1993 reflected a $13.8 million provision for
restructuring, allocated to Specialty Chemicals ($11.8 million), Mineral
Products ($0.3 million) and Other ($1.7 million).
    
 
RESULTS OF OPERATIONS
 
FIRST NINE MONTHS OF 1996 COMPARED WITH FIRST NINE MONTHS OF 1995
 
     For the first nine months of 1996, the Company recorded income from
continuing operations of $51.8 million compared with $41.8 million for the first
nine months of 1995. The 24% increase in income from continuing operations was
the result of higher operating and other income, as well as reduced interest
expense and higher equity income from GAF-Huls.
 
   
     Net sales for the first nine months of 1996 were $544.1 million versus
$530.3 million for the same period in 1995. The sales growth was attributable to
increased sales of specialty chemicals (up $12.6 million), primarily reflecting
increased sales volumes ($14.5 million) and higher sales prices, and also
reflected higher filter products sales (up $2.7 million) due to increased sales
volumes. The increase in sales resulted from higher sales in the U.S., Europe
and the Western Hemisphere, partially offset by lower sales in the Asia-Pacific
region and the
    
 
                                       31
<PAGE>
   
unfavorable effect ($5.4 million) of the stronger U.S. dollar relative to other
currencies in certain areas of the world. Sales for the mineral products
business decreased by $1.8 million (3%) due to lower sales volumes (down $3.4
million) resulting from a lost customer and adverse winter weather conditions in
the first quarter of 1996.
    
 
   
     Operating income for the first nine months of 1996 increased by 7% to
$105.7 million from last year's $99.2 million. The increase in operating income
was due to higher specialty chemicals operating income (up $9.7 million or 12%),
partially offset by lower mineral and filter products results (down $1.1 million

and $2.4 million, respectively). The higher specialty chemicals operating income
resulted primarily from the higher sales levels and improved gross margins (up
2.9 percentage points) due to improved pricing and continued benefits from the
Company's re-engineering program. The gross margin improvement was attributable
to the Company's increased focus on manufacturing process improvements through
increased production yields, improvements in first pass quality, and increased
capacity resulting from shorter production cycle times and increased on-line
time for equipment. In addition, raw material costs were lower in 1996 than in
1995.
    
 
   
     Selling, general and administrative expenses for the first nine months of
1996 increased by $9.4 million (9%) compared with the same period in 1995, and,
as a percent of sales, increased from 18.6% to 19.9%. The most significant
factors for the increase in such expenses were attributable to the Company's
geographic expansion efforts ($2.5 million), increased research and development
spending ($2.2 million) and normal salary increases ($2.5 million).
    
 
   
     Interest expense was $21.9 million for the first nine months of 1996, a 12%
decrease compared with $24.8 million for the same period last year. The decrease
reflected lower interest rates (average borrowing rate of 7.9% in the first nine
months of 1996 versus 8.4% in the first nine months of 1995) and lower average
borrowings (average borrowings of $405 million in the first nine months of 1996
versus $439 million in the first nine months of 1995). Other income, net was
$9.4 million for the first nine months of 1996 compared with $3.9 million last
year, the increase resulting primarily from higher investment income and gains
associated with the Company's program to hedge certain of its foreign currency
exposures.
    
 
1995 COMPARED WITH 1994
 
     The Company recorded income from continuing operations before extraordinary
item in 1995 of $55.1 million compared with $37.1 million in 1994. The 48%
improvement in results for 1995 reflected higher operating income (up $27.9
million), $3.4 million higher equity income from GAF-Huls, and a $6.8 million
increase in other income, partially offset by a $4.4 million increase in
interest expense.
 
   
     Sales for 1995 were $689 million compared with $600 million for 1994. The
15% sales growth was attributable to increased sales in all product lines,
particularly specialty chemicals (up $74.5 million), and reflected double-digit
sales increases in all regions of the world. The sales increase was primarily
the result of increased sales volumes in all product lines (up $49.6 million)
and higher selling prices, and, to a lesser extent, the favorable effect ($14.3
million) of the weaker U.S. dollar relative to other currencies in certain areas
of the world.
    
 
   

     Operating income for 1995 increased by 28% to $127.1 million compared with
$99.2 million for 1994. The increase was attributable to higher sales in all
product lines and improved gross margins (up 1.1 percentage points) due
primarily to higher selling prices, partially offset by higher manufacturing
costs. The gross margin improvement was attributable to the Company's increased
focus on manufacturing process improvements through increased production yields,
improvements in first pass quality, and increased capacity resulting from
shorter production cycle times and increased on-line time for equipment. In
addition, raw materials costs increased in the latter half of 1994, which
increases continued through the first half of 1995. Operating income for the
specialty chemicals business increased by $25.6 million (32%), reflecting the
above factors. Selling, general and administrative expenses for 1995 increased
$14.4 million (12%) over 1994 due to operating expenses associated with higher
sales levels; however, such expenses as a percent of sales have decreased from
23% in 1993 to 19.9% and 19.5% in 1994 and 1995, respectively, primarily as a
result of the Company's cost reduction and productivity programs announced in
1993. The Company's operating margin improved from 16.5% in 1994 to 18.4% in
1995.
    
 
                                       32
<PAGE>
   
     Of the $27.9 million increase in operating income in 1995, domestic
operating income increased by $16.6 million, due primarily to higher selling
prices and increased volumes for specialty chemicals, as well as improved gross
margins, operating income for the European region increased by $12.2 million as
a result of higher sales levels and improved gross margins, operating income for
the Asia-Pacific region increased by $.8 million with higher sales volumes
partially offset by increased expenses associated with the Company's geographic
expansion program, and operating income from other foreign operations declined
by $1.7 million as higher sales were offset by additional expenses attributable
to the geographic expansion program and a nonrecurring 1994 benefit resulting
from the Brazilian government's economic program. To help offset the effects of
inflation, this program allowed companies to add normal billing surcharges in
1994. The operating income benefit to the Company in 1994 of such surcharges was
approximately $1.2 million. As inflation rates dropped, this program was
discontinued in 1995.
    
 
   
     Interest expense for 1995 was $33.1 million, an increase of $4.4 million
from $28.7 million in 1994. The increase was primarily the result of higher
interest rates (average borrowing rate of 8.3% in 1995 versus 6.6% in 1994).
    
 
     Other income (expense), net, comprises net investment income, foreign
exchange gains/losses resulting from the revaluation of foreign
currency-denominated accounts receivable and payable as a result of changes in
exchange rates, and other nonoperating and nonrecurring items of income and
expense. Other income was $6.7 million in 1995 compared with other expense of
$.1 million in 1994. The increase in 1995 was due principally to higher net
investment income (up $10.5 million).
 

1994 COMPARED WITH 1993
 
     The Company recorded income from continuing operations before extraordinary
item in 1994 of $37.1 million compared with $23.8 million in 1993. The 56%
improvement in results for 1994 reflected higher operating income (up $34.1
million) partially offset by a $4.2 million increase in interest expense and a
reduction of $7.3 million in other income (expense), net. Income from continuing
operations in 1993 reflected a retroactive income tax provision of $2.9 million,
representing the effect of a 1% increase in the Federal corporate income tax
rate on the Company's net deferred tax liability as of December 31, 1992, and a
pre-tax provision of $13.8 million, primarily related to the Company's cost
reduction program.
 
   
     Sales for 1994 were $600 million, a 9% increase compared with $548.3
million for 1993. The sales growth reflected increased sales in most product
lines, primarily specialty chemicals (up $47.9 million or 11%) and filters (up
$3.0 million or 12%), in all regions of the world, mainly due to higher volumes
($49.7 million) and, to a lesser extent, a favorable foreign exchange effect of
$4.1 million.
    
 
   
     Operating income for 1994 was $99.2 million compared with $65.1 million for
1993. The improvement was attributable to increased sales volumes and lower
selling, general and administrative expenses, and the absence of the $13.8
million restructuring charge mentioned above, partially offset by lower gross
profit margins due mainly to higher manufacturing costs for specialty chemicals
(up approximately $8 million primarily as a result of raw material cost
increases). The restructuring charge in 1993 was allocated on a segment basis to
specialty chemicals ($11.8 million), mineral products ($.3 million), and other
($1.7 million). See Note 11 to Consolidated Financial Statements. Excluding the
effects of the restructuring charge allocations, operating income for specialty
chemicals increased $20.1 million (34%) in 1994 compared with 1993, reflecting
the factors discussed above, and operating income for mineral products decreased
$2.3 million (14%) as a result of unfavorable pricing. Selling, general and
administrative expenses for 1994 were $119.7 million, down 5% from 1993,
primarily as a result of the Company's cost reduction and productivity programs.
The $13.8 million restructuring charge in 1993 was established to cover costs
associated with severance and related benefits, professional fees, relocations,
and discontinuation of products. Management believes that the Company's cost
reduction and productivity programs have resulted in significantly reduced
operating expenses. The remaining liability as of December 31, 1995 was
approximately $4.7 million and is anticipated to be expended over the next
several years. As a result of such cost reduction and productivity programs, the
Company's selling, general and administrative expenses as a percent of sales
decreased from 23% in 1993 to 19.9% in 1994.
    
 
     Of the $34.1 million increase in operating income in 1994, domestic
operating income increased by $22 million due primarily to higher export sales
to all regions, lower operating expenses and the absence of the
 
                                       33

<PAGE>
prior year's restructuring charge, operating income from Europe increased by
$7.5 million, and operating income from other foreign operations increased by
$4.6 million, mainly in the Asia-Pacific region, in each case after giving
effect to a portion of the $13.8 million restructuring charge in 1993. See Note
12 to Consolidated Financial Statements.
 
   
     Interest expense for 1994 was $28.7 million, an increase of $4.2 millon
from $24.5 million in 1993. The increase was due primarily to higher interest
rates (average borrowing rate of 6.6% in 1994 versus 5.4% in 1993) and, to a
lesser extent, higher average outstanding borrowings (average borrowings of
$482.6 million in 1994 versus $470.4 million in 1993).
    
 
     Other expense was $.1 million in 1994 compared with other income of $7.2
million in 1993. The decrease in 1994 was due primarily to lower net investment
income (down $6.7 million). See Note 1 to Consolidated Financial Statements.
 
LIQUIDITY AND FINANCIAL CONDITION
 
   
     ISP Holdings is essentially a holding company without independent
businesses or operations and, as such, is dependent upon the cash flow of its
approximately 83.5%-owned subsidiary, ISP, in order to satisfy its obligations.
See Note 16 to Consolidated Financial Statements for a discussion of a
subsequent event related to the debt obligations of ISP Holdings. ISP Holdings
expects to satisfy such obligations from, among other things, refinancings of
debt, dividends and loans from ISP, as to which there are restrictions under the
ISP Credit Agreement (defined below) and the indenture relating to the ISP
Notes, payments pursuant to the Tax Sharing Agreement between ISP Holdings and
ISP and debt financings. As of September 29, 1996, after giving effect to the
most restrictive of the aforementioned restrictions, it would have been
permissible for ISP to pay dividends in the aggregate amount of $79.9 million,
of which $66.4 million would have been available to ISP Holdings, and to make
loans to affiliates of $72.7 million.
    
 
     In addition, as ISP's stock price appreciates, ISP Holdings may at some
future time consider selling shares of ISP Common Stock, although it has no
current intention to do so. If ISP Holdings were to own less than 80% of the
outstanding ISP Common Stock, payments pursuant to the ISP Holdings Tax Sharing
Agreement would not be available to it.
 
   
     During the first nine months of 1996, the Company on a consolidated basis
generated cash from operations of $82.5 million, invested $35.7 million in
capital expenditures and an acquisition, generated $34.2 million from net sales
of available-for-sale and held-to-maturity securities, used $83.0 million of
cash for discontinued operations, and generated $89.5 million in cash from the
sale of WAXQ-FM (a discontinued operation), for a net cash inflow of $77.5
million before financing activities. Working capital increased by $3.0 million,
primarily reflecting a $20.6 million increase in accounts receivable due to
higher sales in September 1996 versus December 1995, offset by a $9.7 million

reduction in inventories and an $8.8 million increase in accounts payable and
accrued liabilities. The Company's inventory levels are normally at their
highest levels at the end of each year in order to meet the following year's
first quarter demand. Cash from operations in the first nine months of 1996
included $5.7 million in dividends received from GAF-Huls and $5.6 million in
proceeds from net sales of trading securities.
    
 
     Net cash used in financing activities totaled $89.8 million for the first
nine months of 1996, primarily reflecting a $40.8 million reduction in
borrowings under the Company's bank credit agreements, a $19.1 million decrease
in loans from an affiliate, a $14 million decrease in short-term borrowings and
dividends and net distributions of $6.4 million to the Company's parent company,
GAF. Financing activities also reflected $10.4 million in repurchases by ISP of
its common stock. ISP has adopted a program to repurchase up to a total of
4,500,000 shares of its common stock from time to time in the open market. As of
September 29, 1996, 3,099,300 shares had been repurchased pursuant to the
program.
 
   
     As a result of the foregoing factors, cash and cash equivalents decreased
by $2.3 million during the first nine months of 1996 to $11.8 million (excluding
$100.0 million of trading, available-for-sale and held-to-maturity securities).
    
 
                                       34
<PAGE>
   
     During 1995, the Company on a consolidated basis generated cash from
operations of $143.8 million, reinvested $152.6 million for capital programs and
net purchases of available-for-sale and held-to-maturity securities and
generated cash from discontinued operations of $28.2 million, for a net cash
inflow of $19.4 million before financing activities. Cash from operations in
1995 included $37.6 million in proceeds from net sales of trading securities and
a $7.9 million reduction in the cash surrender value of Company-owned insurance
policies. Cash invested in additional working capital totaled $5.1 million
during 1995. This principally reflected a $10.9 million increase in receivables
due to higher sales levels, partially offset by $2.5 million higher payables and
accrued liabilities.
    
 
     Net cash used in financing activities in 1995 totaled $25.5 million,
primarily reflecting $28.2 million in dividends and net distributions paid to
GAF, principally to fund the redemption by GAF of its outstanding preferred
stock, $16.6 million in repurchases by ISP of its common stock pursuant to its
share repurchase program, a $15.2 million decrease in loans from an affiliate,
and $5.6 million in repayments of long-term debt. The above items of cash
utilization were partially offset by $36.2 million of additional short-term
borrowings and $3.8 million from the sale of receivables.
 
   
     As a result of the foregoing factors, cash and cash equivalents decreased
by $6.0 million during 1995 to $14.1 million (excluding $135.9 million of
trading, available-for-sale and held-to-maturity securities).

    
 
     As of September 29, 1996, the Company's scheduled repayments of long-term
debt for the twelve months ending September 30, 1997 aggregated $.4 million.
 
     On July 26, 1996, ISP entered into a new five-year revolving credit
facility (the 'ISP Credit Agreement') with a group of banks, which provides for
loans of up to $400 million and letters of credit of up to $75 million (see Note
8 to Consolidated Financial Statements).
 
     Borrowings by ISP Holdings and ISP are subject to the application of
certain financial covenants contained in the Indentures and the ISP Credit
Agreement. As of September 29, 1996, on a pro forma basis after giving effect to
the ISP Holdings Transaction, ISP Holdings and ISP were in compliance with such
covenants.
 
     The Company's investment strategy is to seek to earn returns in excess of
money market rates on its available cash while minimizing market risks. There
can be no assurance that the Company will be successful in implementing such
strategy. The Company invests primarily in hedged utility programs,
international and domestic convertible arbitrage, and securities of companies
involved in acquisition or reorganization transactions, including at times,
common stock short positions which are offsets against long positions in
securities which are expected, under certain circumstances, to be exchanged or
converted into the short positions. With respect to its equity positions, the
Company is exposed to the risk of market loss. See Note 1 to Consolidated
Financial Statements.
 
     ISP intends to acquire or develop a European manufacturing facility to meet
the needs of ISP's European business. While the originally anticipated
commencement date of the European project has been deferred because ISP has been
able to implement cost-efficient capacity expansions at its existing
manufacturing facilities, based upon its current analysis of additional
opportunities for expansion of existing capacity, end-use demand, and other
relevant factors, ISP intends to proceed with the project by the end of 1997.
Costs capitalized to date related to this project are included in 'Construction
in progress.' ISP anticipates utilizing internally generated funds, existing
credit facilities and/or independent financing to fund the cost of the project.
 
     Fluctuations in the value of foreign currencies may cause U.S. dollar
translated amounts to change in comparison with previous periods and,
accordingly, the Company cannot estimate in any meaningful way the possible
effect of such fluctuations upon future income. The Company has a policy to
manage these exposures to minimize the effects of fluctuations in foreign
currencies, including entering into foreign exchange contracts in order to hedge
its exposure. In respect of its foreign exchange contracts, the Company
recognized a gain of $5.1 million during the first nine months of 1996 and
losses of $7.4 million and $6.6 million during the years ended December 31, 1995
and 1994, respectively. At September 29, 1996, the equivalent U.S. dollar fair
value of outstanding forward foreign exchange contracts was $175.3 million, and
the amount of deferred gains and losses on such instruments was a net gain of
$2.3 million. The equivalent U.S. dollar fair value of foreign exchange
contracts outstanding as of September 29, 1996 as a hedge of non-local currency
loans was $28.6 million, representing 100% of the Company's foreign currency

exposure with respect to such loans. See Note 1 to Consolidated Financial
Statements.
 
                                       35
<PAGE>
     The objectives of the Company in utilizing interest rate swap agreements
are to lower funding costs, diversify sources of funding and manage interest
rate exposure. As of September 29, 1996, the total notional amount of interest
rate swaps outstanding for continuing operations was $200 million and the amount
of underlying debt relating to such swaps was $200 million. By utilizing
interest rate swap agreements, the Company reduced its interest expense related
to continuing operations by $2.3 million in the first nine months of 1996, $1.8
million in 1995 and $5.3 million in 1994. See Note 8 to Consolidated Financial
Statements.
 
     The Company does not believe that inflation has had a material effect on
its results of operations during the past three years and the nine months ended
September 29, 1996. However, there can be no assurance that the Company's
business will not be affected by inflation in the future.
 
     In 1995, the Financial Accounting Standards Board issued SFAS No. 121,
relating to accounting for impairment of long-lived assets, which is required to
be adopted in 1996. The Company does not anticipate that the implementation of
SFAS No. 121 will have a material effect on the Company's results of operations
or financial position.
 
     ISP has received conditional site designation from the New Jersey Hazardous
Waste Facilities Siting Commission for the construction of a hazardous waste
treatment, storage and disposal facility at its Linden, New Jersey property,
which designation has been appealed to the courts by the City of Linden. ISP
estimates that the cost of constructing the facility will be approximately $100
million and, if approved, the facility is anticipated to be in operation three
years after commencement of construction. ISP anticipates utilizing internally
generated cash and/or seeking project or other independent financing therefor.
Accordingly, ISP would not expect such facility to impact materially its
liquidity or capital resources.
 
     The Company, together with other companies, is a party to a variety of
administrative proceedings and lawsuits involving environmental matters. See
'Business--Environmental Litigation' for further discussion, which is
incorporated herein by reference.
 
                                       36


<PAGE>
                           THE SPIN OFF TRANSACTIONS
 
   
     General.  On January 1, 1997, GAF effected a series of transactions
involving GAF's subsidiaries and certain assets of GAF's subsidiaries that
resulted, among other things, in the capital stock of ISP Holdings (whose
principal asset is approximately 83.5% of the issued and outstanding capital
stock of ISP) being distributed to the stockholders of GAF. As a result of such
distribution, ISP Holdings and ISP are no longer direct or indirect subsidiaries
of GAF, while BMCA and USI and certain other assets and liabilities, including
liabilities for asbestos-related claims, remain part of GAF, but are not assets
or liabilities of ISP Holdings. Among other things, as part of the Spin Off
Transactions:
    
 
   
          1.  ISP borrowed approximately $30 million under the ISP Credit
              Agreement (after giving effect to utilization of proceeds of the
              ISP Loan) in order to repay to G-I Holdings all amounts owed by
              ISP to G-I Holdings;
    
 
   
          2.  G-I Holdings purchased Discount Notes from ISP Holdings for an
              aggregate cash purchase price equal to $45.8 million, representing
              the sum of $45 million plus an amount sufficient to pay ISP
              Holdings' fees and expenses related to the Spin Off Transactions
              (not including those fees and expenses already paid by ISP
              Holdings related to the ISP Holdings Transactions);
    
 
          3.  All Discount Notes purchased in the Tender Offer by ISP Holdings
              (other than those Discount Notes sold to G-I Holdings pursuant to
              the Repurchase or as provided in paragraph 2 above) and all 10%
              Notes accepted in the Old Exchange Offer by ISP Holdings were
              contributed to G-I Holdings by ISP Holdings as a capital
              contribution and cancelled by G-I Holdings;
 
   
          4.  Through a series of distributions, all shares of ISP Common Stock
              owned by GAF and its subsidiaries, including GFC, were distributed
              to ISP Holdings;
    
 
          5.  ISP Holdings distributed all of the outstanding capital stock of
              G-I Holdings to GAF; and
 
          6.  The capital stock of ISP Holdings was distributed to the
              stockholders of GAF.
 
     IRS Ruling.  In November 1996, GAF received the IRS Ruling. The IRS Ruling
was conditioned upon the accuracy of certain representations contained in GAF's
request therefor as to certain facts and circumstances with respect to the Spin

Off Transactions. If the Spin Off Transactions do not qualify as 'tax-free spin
offs' under the Internal Revenue Code, the GAF Tax Group would recognize gain,
but not loss, as if the common stock of ISP Holdings, G-I Holdings and ISP was
sold at the fair market value thereof. The gain recognized would be an amount
equal to the fair market value of the ISP Holdings common stock, G-I Holdings
common stock and ISP Common Stock in excess of the adjusted tax basis in such
shares of common stock as determined immediately prior to the Spin Off
Transactions. The tax on the income would be payable by GAF. To the extent not
paid by GAF, each member of the GAF Tax Group as it existed prior to the Spin
Off Transactions (including ISP Holdings, ISP and their respective subsidiaries)
would be jointly and severally liable for such tax liability. See 'Certain
Relationships--Mutual Indemnification.'
 
   
     HLHZ Opinion.  As a condition to the consummation of the Spin Off
Transactions, the Boards of Directors of GAF, ISP Holdings, GFC, G-I Holdings
and G Industries received a satisfactory opinion regarding the solvency of such
companies and the permissibility of certain distributions contemplated by the
Spin Off Transactions under Section 170 of the Delaware General Corporation Law.
In written opinions dated September 12, 1996 and December 19, 1996, HLHZ stated
that, based upon the considerations set forth therein and on other factors it
deemed relevant, both before and after giving effect to the Transactions, with
respect to each of GAF, ISP Holdings, GFC, G-I Holdings and G Industries, in
each case on a stand alone and consolidated basis, (a) the fair value and
present fair saleable value of such company's aggregate assets exceed and would
exceed such company's stated liabilities and identified contingent liabilities;
(b) such company is and would be able to pay its debts as they mature; (c) the
capital remaining in such company after the Spin Off Transactions is not and
would not be unreasonably small for the business in which such company is
engaged, as management has indicated it is now conducted and is proposed to be
conducted following consummation of the Spin Off Transactions; and (d) the
excess of the fair value of aggregate assets of such company over the sum of the
stated liabilities and identified contingent liabilities of such company plus
the stated capital of such company, equals or exceeds and would equal or exceed
the value of the assets transferred to stockholders of such company in the Spin
Off Transactions.
    
 
                                       37
<PAGE>
     In rendering its opinions, HLHZ made such reviews, analyses and inquiries
as it deemed necessary and appropriate under the circumstances, including a
review of G-I Holdings' annual reports and filings with the Commission, a review
of material agreements, meetings with members of the senior management of GAF
and its then subsidiaries (the 'GAF Group') to discuss operations, financial
condition, future prospects and projected operations and performance, visits to
certain facilities and business offices of the GAF Group, review of forecasts
and projections prepared by management, and review of other publicly available
financial data for G-I Holdings, BMCA and ISP and certain companies that HLHZ
deems comparable to ISP Holdings.
 
     HLHZ relied upon and assumed, without verification, that the financial
forecasts and projections had been reasonably prepared and reflected the best
currently available estimates of the future financial results and condition of

the GAF Group, and that there had been no material change in the assets,
financial condition, business or prospects of the GAF Group since the date the
most recent financial statements were made available to HLHZ. In addition, HLHZ
relied upon and assumed, without verification, the accuracy of the stated amount
of contingent liabilities identified to them and valued by GAF, including with
respect to current and future asbestos claims and cash flows.
 
     In addition, HLHZ did not independently verify the accuracy and
completeness of the information supplied to it, and did not make any physical
inspection or independent appraisal of any of the properties or assets of any
member of the GAF Group. HLHZ's opinions were based on business, economic,
market and other conditions as they existed and could be evaluated at the date
its opinions were rendered.
 
     GAF engaged HLHZ and paid HLHZ a fee of $175,000 for services rendered in
connection with the Spin Off Transactions, including services it has conducted
to render its opinions.
 
                         THE ISP HOLDINGS TRANSACTIONS
 
THE TENDER OFFER
 
     On October 18, 1996, ISP Holdings consummated the Tender Offer for all of
the outstanding Discount Notes. Approximately 99% of the outstanding Discount
Notes were tendered pursuant to the Tender Offer and approximately $6.3 million
in aggregate principal amount remain outstanding. All Discount Notes validly
tendered and purchased in the Tender Offer, other than Discount Notes purchased
by G-I Holdings from ISP Holdings, were contributed to G-I Holdings by ISP
Holdings as a capital contribution in connection with the consummation of the
Spin Off Transactions and cancelled by G-I Holdings. In connection with such
offer to purchase, ISP Holdings obtained the consent of the tendering holders of
the Discount Notes to the Discount Note Amendments which modified or eliminated
certain of the restrictive covenants contained in the Discount Note Indenture,
including those covenants that would have prohibited the Spin Off Transactions.
 
     Concurrently with the consummation of the Tender Offer, ISP Holdings made
the ISP Loan to ISP and G-I Holdings effected the Repurchase, the proceeds of
which were used by ISP Holdings, together with the net proceeds of the 9% Note
Offering (after giving effect to the ISP Loan), to consummate the Tender Offer
and to pay expenses in connection with the ISP Holdings Transactions.
 
THE OLD EXCHANGE OFFER
 
     On October 18, 1996, ISP Holdings consummated the Old Exchange Offer
pursuant to which approximately 99% of the outstanding 10% Notes were tendered
in exchange for the Old 9 3/4% Notes. In connection with such exchange offer,
ISP Holdings obtained the consent of the tendering holders of the 10% Notes to
the 10% Note Amendments, which modified or eliminated certain of the restrictive
covenants contained in the 10% Note Indenture, including those covenants that
would have prohibited the Spin Off Transactions. All 10% Notes validly tendered
and accepted in the Old Exchange Offer were contributed to G-I Holdings by ISP
Holdings as a capital contribution in connection with the consummation of the
Spin Off Transactions and cancelled by G-I Holdings.
 

THE 9% NOTE OFFERING
 
     On October 18, 1996, ISP Holdings issued and sold $325 million in aggregate
principal amount of the Old 9% Notes in the 9% Note Offering.
 
                                       38


<PAGE>
                                    BUSINESS
 
ISP HOLDINGS
 
   
     The business of ISP Holdings consists of owning approximately 83.5% of the
issued and outstanding ISP Common Stock. The remaining 17% of the outstanding
ISP Common Stock is publicly held and traded on the New York Stock Exchange. ISP
Holdings was formed in 1996 in order to consummate the ISP Holdings
Transactions. ISP Holdings is controlled by Samuel J. Heyman, Chairman and Chief
Executive Officer of GAF, ISP Holdings, G-I Holdings, ISP and BMCA. Mr. Heyman
also controls GAF and its subsidiaries. See 'Security Ownership of Certain
Beneficial Owners and Management.'
    
 
ISP
 
     ISP is a leading multinational manufacturer of specialty chemicals, mineral
products, filter products and advanced materials.
 
     ISP, incorporated in Delaware in 1991, operates its business exclusively
through 19 domestic subsidiaries, including ISP Chemicals Inc., ISP Technologies
Inc., ISP Van Dyk Inc. and ISP Fine Chemicals Inc., 36 international
subsidiaries and GAF-Huls, the joint venture with Huls AG, in which ISP has a
50% interest.
 
SPECIALTY CHEMICALS
 
     o Products and Markets.  ISP manufactures more than 325 specialty chemicals
having numerous applications in consumer and industrial products. ISP uses
proprietary technology to convert various raw materials, through a chain of one
or more processing steps, into increasingly complex and higher value added
specialty products to meet specific customer requirements. More than 200 of
ISP's specialty chemical products are derived from acetylene, including
intermediates, solvents, vinyl ethers, and polymers, and sales of these products
represent the majority of ISP's specialty chemical sales.
 
     ISP's specialty chemicals consist of nine main groups of products: vinyl
ether polymers, polyvinyl pyrrolidone polymers, solvents, intermediates,
specialty preservatives, sunscreens, emollients, pearlescent pigments and fine
chemicals.
 
     Vinyl ether polymers are used by the cosmetics, personal care,
pharmaceutical and health-related industries, primarily in hair care and dental
care products. Vinyl ether monomers and oligomers are used in coatings and inks
for both consumer and industrial products.
 
     Polyvinyl pyrrolidone (PVP) polymers are used primarily in cosmetics,
personal care, pharmaceutical and health-related products, food and beverages,
and detergent formulations. Examples are drug and vitamin tablet binders and
disintegrants; clarifiers and chill-hazing elimination agents for beer, wine and
fruit juices; microbiocidal products for human and veterinary applications; hair
care products such as hair sprays, mousses, conditioners, gels and glazes;

ingredients in water-resistant mascaras, sunscreens and lipsticks; specialty
coatings, adhesives, ink jet inks and media for consumer and industrial
applications; and dispersants and binders in agricultural chemical formulations.
 
     Solvents are sold to customers for use in agricultural chemicals,
pharmaceuticals, coatings, wire enamels, adhesives, plastics, electronics
coating and cleaning applications, petroleum extraction and specialty cleaners.
ISP's family of solvents includes, among others, N-methyl-2-pyrrolidone,
gamma-butyrolactone, 2-pyrrolidone and tetrahydrofuran, many of which are used
by ISP as raw materials in the manufacture of monomers and polymers.
 
     Intermediates are manufactured primarily for use by ISP as raw materials in
manufacturing solvents and polymers. Some intermediates are also sold to
customers for use in the manufacture of engineering plastics and elastomers,
agricultural chemicals, oil production auxiliaries and other products.
Butanediol, an intermediate produced by ISP, is an essential raw material in the
manufacture of polybutylene terephthalate ('PBT') thermoplastic resins and
polyurethane elastomers, which are used in the automotive, electronics and
appliance industries.
 
                                       39
<PAGE>
     Specialty preservatives are proprietary products that are marketed
worldwide to the cosmetics, personal care and household industries. ISP sells a
number of preservative products, including Germall(Registered) 115,
Germall(Registered) II, Germaben(Registered) II, Germaben(Registered) II-E,
Suttocide(Registered) A and LiquaPar(Registered) Oil. Uses include infant care
preparations, eye and facial makeup, after-shave and nail, bath, hair and skin
preparations.
 
     ISP Van Dyk Inc. produces three multifunctional specialty chemical product
lines which ISP markets primarily to the cosmetics and personal care
industry--ultraviolet absorber chemicals, the principal active ingredients in
sunscreens; pearlescent pigments, which provide the pearly or lustrous color in
lipsticks, eye shadows and other cosmetics; and emollients and emulsifiers,
which are used as moisturizing and softening agents in a variety of creams and
lotions, hair care products and other cosmetics. ISP Van Dyk's
Escalol(Registered), Pearl-Glo(Registered)and Ceraphyl(Registered) products are
widely recognized for their respective sunscreen, pigment and emollient
properties.
 
     ISP Fine Chemicals Inc. produces a broad range of pharmaceutical
intermediates, biological buffers, pheromones and several bulk active
pharmaceuticals which serve the pharmaceutical, biotechnology, agricultural and
chemical process industries. Fine chemicals are extremely specialized products,
made in small quantities, which because of their complexity can be priced at
several hundred to several thousand dollars per kilogram. ISP Fine Chemicals
Inc. also provides a custom manufacturing capability serving the pharmaceutical,
biotechnology, agricultural and chemical process industries.
 
     o Marketing and Sales.  ISP markets its specialty chemicals through a
worldwide marketing and sales force, typically chemists or chemical engineers,
who work closely with ISP's customers to familiarize themselves with their
customers' products, manufacturing processes and markets. ISP conducts its

marketing and domestic sales from ISP's headquarters in Wayne, New Jersey and
regional offices strategically located throughout the United States.
 
     o International Operations.  ISP markets all of its specialty chemicals
worldwide. ISP conducts its international operations through 36 subsidiaries and
43 sales offices located in Western and Eastern Europe, Canada, Latin America
and the Asia-Pacific region. Services of local distributors are also used to
reach markets that might otherwise be unavailable to ISP.
 
     ISP had in excess of 60% of its international sales in 1995 in countries in
Western Europe and Japan which are subject to currency exchange rate fluctuation
risks. For a discussion of the Company's policy regarding the management of
these risks, see 'Management's Discussion and Analysis of Financial Condition
and Results of Operations--Liquidity and Financial Condition.' Other countries
in which the Company has sales are subject to additional risks, including high
rates of inflation, exchange controls, government expropriation and general
instability.
 
     International sales in 1995 of ISP's specialty chemicals, excluding sales
by GAF-Huls, were approximately 45% of ISP's total 1995 sales. GAF-Huls, a joint
venture in which ISP holds a 50% interest, produces certain intermediates and
solvents. The GAF-Huls plant is located in Marl, Germany.
 
     o Raw Materials.  Because of the multi-step processes required to
manufacture ISP's specialty chemicals, ISP believes that its raw material costs
represent a smaller percentage of the cost of goods sold than for most other
chemical companies. It is estimated that approximately one-third of ISP's
manufacturing costs are for raw materials (including energy and packaging). As a
result, fluctuations in the pricing of raw materials have less impact on ISP
than on those chemical companies for which raw materials costs represent a
larger percent of manufacturing costs.
 
     The principal raw materials used in the manufacture of ISP's specialty
chemicals are acetylene, methanol and methylamine. Most of these raw materials
are obtained from outside sources pursuant to long-term supply agreements.
Acetylene, a significant raw material used in the production of most of ISP's
specialty chemicals, is obtained by ISP for domestic use from two unaffiliated
suppliers pursuant to long-term supply contracts. At ISP's Texas City and
Seadrift, Texas plants, acetylene is supplied via pipeline by a neighboring
large multinational company that generates this raw material as a by-product
from ethylene manufacture. At ISP's Calvert City, Kentucky facility, acetylene
is supplied via pipeline by a neighboring company that generates it from calcium
carbide. The acetylene utilized by GAF-Huls is produced by Huls AG, using a
proprietary electric arc process, sourced from various hydrocarbon feedstocks.
ISP believes that this diversity of supply sources, using a number 
 
                                       40
<PAGE>
of production technologies (ethylene by-product, calcium carbide and electric
arc), provides the Company with a reliable supply of acetylene. In the event of
a substantial interruption in the supply of acetylene from current sources, no
assurances can be made that ISP would be able to obtain as much acetylene from
other sources as would be necessary to meet its supply requirements. ISP has a
long-standing agreement with GAF-Huls to import

butanediol into the United States for use as a feedstock for the production of
ISP's solvents and polymers. ISP has not experienced an interruption of its
acetylene supply that has had a material adverse effect on its sales of
specialty chemicals. With regard to raw materials other than acetylene, ISP
believes that in the event of a supply interruption it could obtain adequate
supplies from alternate sources.
 
     Natural gas and raw materials derived from petroleum are used in many of
ISP's manufacturing processes and, consequently, the price and availability of
petroleum and natural gas could be material to ISP's operations. During 1995,
crude oil and natural gas supplies remained ample, while prices demonstrated
small seasonal and weather-related variations. The same was true for
petroleum-derived raw materials during the first nine months of 1996. While
there were significant price increases for natural gas in January 1996 due to
increased demand as a result of harsh weather conditions, pricing eased in the
following months.
 
     Methanol, which, due to a shortage of supply, experienced a substantial
increase in price in the latter half of 1994 and the first half of 1995,
experienced a significant decline in price in the second half of 1995 (to levels
below the lowest prices encountered in 1994), as a result of increases in
capacity by methanol suppliers. During the first nine months of 1996, methanol
availability remained ample and prices remained relatively constant and in line
with prices encountered during the second half of 1995. Due to the substantial
increases in methanol capacity, ISP believes, although there can be no
assurance, that the market conditions which caused the sudden rise in methanol
prices will not reoccur in the near future.
 
     o Strategy.  ISP's strategy for future growth involves (i) the introduction
of new products and the development of new applications for existing products,
(ii) geographic expansion and penetration of new markets and (iii) the selected
acquisition of businesses which complement ISP's existing businesses.
 
     ISP continued in 1995 its emphasis on the development of new products and
new applications for existing products. ISP expanded the development of its
broad product line for the hair care industry, where it believes there are
attractive opportunities for environmentally-friendly chemicals. In this regard,
ISP has been involved over the past several years in an intensive effort to
tailor its family of products for the hair care industry so as to enable its
customers to meet stringent regulatory requirements mandating reduction of
volatile organic compounds ('VOCs'), while at the same time improving the
performance characteristics of these products in order to satisfy consumer
preferences. To this end, ISP has introduced since the beginning of 1994 a
number of new products for the hair care industry, including the following:
Gantrez(Registered) A-425, a hair spray polymer whose molecular weight has been
optimized in order to allow manufacturers to satisfy 80% VOC requirements while
enhancing the performance characteristics of ISP's current Gantrez(Registered)
products and providing for formulations covering a wide range of desired
properties from natural to stiff feel, so as to appeal to different consumer
styles which tend to vary from one region of the world to another;
Gafquat(Registered) HSi and PVP/Si-10 encapsulated silicone products, which
combine ISP's Gafquat(Registered) and PVP products with silicone to provide a
silky feel for use in hair conditioners, shampoos and mousses; and
H2OLD(Trademark) EP-1, a versatile polymer for use in low VOC or alcohol-free

formulations for hair sprays, mousses and gels and designed so as to satisfy a
preference on the part of certain consumers. ISP also introduced the next
generation of its successful Gafquat(Registered) product, a hair styling
conditioner that provides improved holding characteristics, especially at high
humidity levels. In addition, ISP has recently introduced and began selling in
1996 a new hair protectant product, Escalol(Registered)HP-610, which helps
protect hair from the damaging effects of the sun.
 
     In addition to new products for the hair care industry, ISP has introduced
since the beginning of 1994 a number of other new products for use in the
cosmetics, skin care, household, industrial and institutional cleaner,
agricultural and oil and gas industries, examples of which include the
following: Stabileze(Registered) QM, a quick mix viscosity enhancing polymer
that provides desired controlled thickening properties in skin and hair care
formulations; PVP K-30A, a cosmetic grade PVP specifically designed for skin
care use in mascara and eye liners; Cerasynt(Registered) IP-V and
Cerasynt(Registered) SD-V, vegetable-based emulsifiers for hair and skin care; a
family of PVP anionic copolymers with applications in a variety of personal
care, specialty industrial coatings, and household, industrial and institutional
cleaner uses; and a family of agricultural adjuvant products, utilizing ISP's
new 
 
                                       41
<PAGE>
proprietary microemulsion technology which provide pesticides, herbicides,
fungicides and other related agricultural chemicals with greater adherence,
thereby improving performance and reducing environmental risk.
 
     ISP has also focused its research and development efforts on the
improvement of manufacturing efficiency at its plants. The efforts to increase
productivity, reduce waste and inefficiency and improve the overall quality of
ISP's manufacturing operations have yielded increased manufacturing capacity
with minimal capital investment, while providing for manufacturing cost savings.
 
     ISP's specialty chemicals business has continued its emphasis on increased
geographic penetration, with particular focus on the Asia-Pacific and Latin
American regions. In order to further the geographic expansion of its specialty
chemicals business, ISP has opened since the beginning of 1994 new sales and
marketing operations, and/or added to its existing presence where it could
increase market penetration, in more locations than in any comparable period in
the history of its business, with operations having been opened or substantially
augmented in Beijing, Chengdu, Shanghai and Guangzhou, China; Moscow; Buenos
Aires; Bombay; Warsaw; Bangkok and Jakarta. ISP is increasing its geographic
penetration throughout the world not only with the opening of sales and
marketing operations, but also as a result of the increased specialization of
its sales force along industry lines, the hiring of additional technical staff
to assist ISP's sales force, and a substantial increase in sales staff.
 
     In addition, ISP's strategy is to acquire niche businesses with
characteristics similar to ISP's, involving high value-added products,
significant market shares and barriers to entry, and product lines which
complement ISP's own products. Furthermore, the acquired product lines can be
expanded by use of ISP's technology, marketing expertise and worldwide
distribution network.
 


MINERAL PRODUCTS
 
     o Products and Markets.  ISP manufactures mineral products consisting of
ceramic-coated colored roofing granules, which are produced from rock deposits
that are mined and crushed at ISP's quarries and are colored and coated using a
proprietary process. ISP's mineral roofing granules are sold primarily to the
North American roofing industry for use in the manufacture of asphalt roofing
shingles, for which they provide weather resistance, decorative coloring, heat
deflection and increased weight. ISP is the second largest of only two major
suppliers of colored roofing granules in North America, the other being
Minnesota Mining & Manufacturing Company. ISP also markets granule by-products
for use in the construction and maintenance of fast dry, clay-like tennis
courts.
 
     ISP estimates that more than 80% of the asphalt shingles currently produced
by the roofing industry are sold for the reroofing/replacement market, in which
demand is driven not by the pace of new home construction but by the needs of
homeowners to replace existing roofs. Homeowners generally replace their roofs
either because they are worn, thereby creating concerns as to weather-tightness,
or because of the homeowners' desire to upgrade the appearance of their homes.
ISP estimates that the balance of the roofing industry's asphalt shingle
production historically has been sold primarily for use in new housing
construction. Sales of ISP's colored mineral granules have benefitted from a
trend toward the increased use of heavyweight, three-dimensional laminated
roofing shingles which results in both functional and aesthetic improvements,
which require, on average, approximately 60% more granules than traditional
three-tab, lightweight roofing shingles.
 
     o Marketing and Sales.  BMCA purchases 100% of its colored roofing granule
requirements from ISP (except for the requirements of its California roofing
plant which are supplied by a third party). These purchases constituted
approximately one-half of ISP's mineral products net sales in 1995. Sales to
BMCA were made under a requirements contract which was renewed for one year
effective January 1, 1997 and is subject to annual renewal unless terminated by
BMCA or ISP. In addition, in December 1995, USI commenced purchasing
substantially all of its requirements for colored roofing granules from ISP
(except for the requirements of its Stockton, California and Corvallis, Oregon
plants which are supplied by a third party) pursuant to a requirements contract
which expires December 31, 1997. See 'Certain Relationships.'
 
     o Raw Materials.  ISP owns rock deposits that have specific performance
characteristics, including weatherability, the ability to reflect UV light,
abrasion-resistance, non-staining characteristics and the ability to absorb
pigments. ISP owns three quarries, each with proven reserves, based on current
production levels, of more than 20 years.

 
                                       42

<PAGE>
FILTER PRODUCTS AND ADVANCED MATERIALS
 
     ISP manufactures and sells filter products, consisting of pressure filter
vessels, filter bags and filter systems, and sells cartridges and cartridge
housings. These filter products are designed for the removal of macroscopic
contaminants in the treatment of process liquids, with the paint, automotive,
chemical, pharmaceutical, petroleum and food and beverage industries accounting
for more than 90% of ISP's 1995 net sales of filter products.
 
     ISP manufactures pressure filter vessels at manufacturing facilities in
Brazil, Canada and Germany, which serve both local and international markets.
ISP also manufactures filter bags in Belgium, Canada, Singapore, Brazil and the
United States and supplies filter products worldwide through its subsidiaries,
sales offices and distributors.
 
     ISP manufactures a variety of advanced materials, consisting of high-purity
carbonyl iron powders, sold under ISP's trademark Micropowder(Trademark), used
in a variety of advanced technology applications for the aerospace and defense,
electronics, powder metallurgy, pharmaceutical and food industries. Using
proprietary technology, ISP manufactures more than 50 different grades of
Micropowder(Trademark) iron, one of which is sold under the trademark
Ferronyl(Registered), for use as a vitamin supplement.
 
     The primary markets for ISP's Micropowder(Trademark) are the domestic
defense industry, which employs these products in a variety of coating systems
for stealth purposes in aircraft and naval ships, and the emerging metal
injection molding segment of the powder metallurgy industry. ISP is the sole
domestic manufacturer of carbonyl iron powders.
 
     ISP manufactures a line of processless, electronically imaged film products
including Rad-Sure(Registered), which is a radiation sensitive film strip
affixed to blood bags to indicate whether or not they have been properly
irradiated.
 
COMPETITION
 
     ISP believes that it is either the first or second largest seller worldwide
of its specialty chemicals derived from acetylene other than butanediol and
tetrahydrofuran. Butanediol, which ISP produces primarily for use as a raw
material, is also manufactured by a limited number of companies in the United
States, Germany, Japan and Korea. Tetrahydrofuran is manufactured by a number of
companies throughout the world. While there are companies, other than ISP and
its principal competitor, that manufacture a limited number of ISP's other
specialty chemicals, the market position of these companies is much smaller than
that of ISP (other than as to solvents and intermediates, with respect to which
there is a significant third competitor). In addition to ISP's competition as
noted above, there are other companies that produce substitutable products for a
number of ISP's specialty chemicals. These companies compete with ISP in the
personal care, pharmaceutical, beverage preservative and industrial markets and
have the effect of limiting ISP's market penetration and pricing flexibility.
 
     Beginning in 1994, ISP experienced a dramatic improvement in the severe
competitive conditions which had adversely affected ISP's intermediates and

solvents business during the three preceding years as a result of an additional
competitor having entered the market in 1991. As a result of improved worldwide
demand for ISP's intermediates and solvents products coming principally, with
respect to intermediates, from PBT engineering plastic producers for an
increasingly wide range of both automotive and electrical component applications
and, with respect to solvents, from increased demand for a number of existing
and new applications, together with a regulatory and customer-driven trend to
replace chlorinated and other volatile solvents with ISP's safer solvent,
N-methyl-2-pyrrolidone ('NMP'), industry-wide capacity utilization rates for
these products substantially increased in 1994, 1995 and 1996. As a result,
while butanediol ('B1D') and NMP prices had declined fairly substantially from
the beginning of 1992 to mid-1994, higher capacity utilization rates, together
with substantial price increases of methanol, enabled ISP to implement worldwide
price increases in 1994 and 1995, establishing B1D prices at levels higher than
in the recent past and reversing a significant portion of the previous decline
in NMP prices. Future competitive conditions will depend in large measure on
future worldwide demand for ISP's customers' end-use products and the impact of
the anticipated entrance of a new competitor in the B1D and NMP European markets
in 1997.

     With regard to its mineral products, ISP has only one major and one smaller
competitor and believes that competition has been limited by: (i) the
substantial capital expenditures associated with the construction of new
 
                                       43
<PAGE>
mineral processing and coloring plants and the acquisition of suitable rock
reserves; (ii) the limited availability of proven rock sources; (iii) the
complexity associated with the construction of a mineral processing and coloring
plant, together with the technical know-how required to operate such a plant;
(iv) the need to obtain, prior to commencing operations, reliable data over a
substantial period of time regarding the weathering of granules in order to
assure the quality and durability of the product; and (v) the difficulty in
obtaining the necessary permits to mine and operate a quarry.
 
     With respect to filter products, ISP competes with a number of companies
worldwide. With respect to advanced materials, ISP is the sole domestic
manufacturer of carbonyl iron powders and one of only two manufacturers
worldwide.
 
     Competition is largely based upon product and service quality, technology,
distribution capability and price. ISP believes that it is well positioned in
the marketplace as a result of its broad product lines, sophisticated technology
and worldwide distribution network.
 
RESEARCH AND DEVELOPMENT
 
     ISP's worldwide research and development expenditures were $21.2 million,
$20.3 million and $21.9 million in 1993, 1994 and 1995, respectively.
 
     ISP's research and development department is located primarily at ISP's
worldwide technical center and laboratories in Wayne, New Jersey and additional
research and development is conducted at the Calvert City, Kentucky, Texas City,
Texas, Chatham, New Jersey, Belleville, New Jersey, and Columbus, Ohio plant

sites and technical centers in the United Kingdom, Germany, China and Singapore.
ISP's mineral products research and development facility, together with its
recently opened customer design and color center, is located at Hagerstown,
Maryland.
 
ENVIRONMENTAL SERVICES
 
     ISP has received conditional site designation for the construction of a
hazardous waste treatment, storage and disposal facility at its Linden, New
Jersey property. If ISP is successful in securing the site designation and the
necessary permits to construct and operate the hazardous waste facility, ISP
intends to develop and operate the facility in a separate subsidiary, either on
its own or in a joint venture with a suitable partner. ISP estimates that the
cost of constructing the facility will be approximately $100 million and, if
approved, the facility is anticipated to be in operation three years after
commencement of construction. ISP anticipates utilizing internally generated
cash and/or seeking project or other independent financing.
 
PROPERTIES
 
     The corporate headquarters and principal research and development
laboratories of ISP are located at a 100-acre campus-like office and research
park owned by a subsidiary of ISP at 1361 Alps Road, Wayne, New Jersey 07470.
The premises are subject to a first mortgage. ISP Holdings maintains its
principal office at 818 Washington Street, Wilmington, Delaware 19801, telephone
(302) 428-0847.
 
     The principal domestic and foreign real properties either owned by, or
leased to, ISP are described below. Unless otherwise indicated, the properties
are owned in fee. In addition to the principal facilities listed below, ISP
maintains sales offices and warehouses in the United States and abroad,
substantially all of which are in leased premises under relatively short-term
leases.
 
                                       44
<PAGE>
     ISP Holdings does not directly own or lease any real property.
 
<TABLE>
<CAPTION>
LOCATION                              FACILITY                              PRODUCT LINE
- ------------------------------------  ------------------------------------  ------------------------------------
<S>                                   <C>                                   <C>
                                                    DOMESTIC
Alabama
  Huntsville........................  Plant*                                Advanced Materials
Kentucky
  Calvert City......................  Plant                                 Specialty Chemicals
Maryland
  Hagerstown........................  Research Center, Design Center,       Mineral Products
                                      Sales Office
Missouri
  Annapolis.........................  Plant, Quarry                         Mineral Products
New Jersey

  Belleville........................  Plant, Sales Office, Research         Specialty Chemicals
                                      Center, Warehouse*
  Bridgewater.......................  Sales Office                          Specialty Chemicals
  Chatham...........................  Plant, Sales Office, Research         Specialty Chemicals
                                      Center, Warehouse*
  Wayne.............................  Headquarters, Corporate               Specialty Chemicals; Filter Products
                                      Administrative Offices, Research      and Advanced Materials
                                      Center
Ohio
  Columbus..........................  Plant, Sales Office                   Fine Chemicals
Pennsylvania
  Blue Ridge Summit.................  Plant, Quarry                         Mineral Products
Tennessee
  Memphis...........................  Plant*, Warehouse*, Distribution      Filter Products
                                      Center*
Texas
  Seadrift..........................  Plant                                 Specialty Chemicals
  Texas City........................  Plant                                 Specialty Chemicals
Wisconsin
  Pembine...........................  Plant, Quarry                         Mineral Products
                                                 INTERNATIONAL
Belgium
  Sint-Niklaas......................  Plant, Sales Office, Distribution     Specialty Chemicals and Filter
                                      Center                                Products
Brazil
  Sao Paulo.........................  Plant*, Sales Office*, Distribution   Specialty Chemicals and Filter
                                      Center*                               Products
Canada
  Mississauga, Ontario..............  Plant*, Sales Office*, Distribution   Specialty Chemicals
                                      Center*
  Oakville, Ontario.................  Plant*                                Filter Products
Germany
  Hamburg...........................  Plant*                                Filter Products
Great Britain
  Guildford.........................  European Headquarters*, Research      Specialty Chemicals
                                      Center*
</TABLE>
 
                                       45
<PAGE>
<TABLE>
<CAPTION>
LOCATION                              FACILITY                              PRODUCT LINE
- ------------------------------------  ------------------------------------  ------------------------------------

<S>                                   <C>                                   <C>
India
  Nagpur............................  Plant                                 Specialty Chemicals
Singapore
  Southpoint........................  Plant*, Sales Office*, Distribution   Specialty Chemicals and Filter
                                      Center*, Asia-Pacific Headquarters*,  Products
                                      Warehouse*
Affiliate:
  GAF-Huls Chemie GmbH Marl,          Plant, Sales Office                   Specialty Chemicals

  Germany...........................
</TABLE>
 
- ------------------
* Leased Property
 
     The Company believes that its subsidiaries plants and facilities, which are
of varying ages and are of different construction types, have been
satisfactorily maintained, are in good condition, are suitable for their
respective operations and generally provide sufficient capacity to meet
production requirements. Each plant has adequate transportation facilities for
both raw materials and finished products. In 1995, the Company made capital
expenditures in the amount of $38.3 million relating to plant, property and
equipment.
 
PATENTS AND TRADEMARKS
 
     ISP owns approximately 313 domestic and 123 foreign patents and owns or
licenses approximately 118 domestic and 1,350 foreign trademark registrations
related to the business of ISP. The Company does not believe that any single
patent, patent application or trademark is material to ISP's business or
operations.
 
     The Company believes that the duration of the existing patents and patent
licenses is satisfactory.
 
ENVIRONMENTAL COMPLIANCE
 
     Since 1970, a wide variety of federal, state and local environmental laws
and regulations relating to environmental matters (the 'Regulations') have been
adopted and amended. By reason of the nature of the operations of the Company
and its predecessor and certain of the substances that are, or have been used,
produced or discharged at their plants or at other locations, the Company is
affected by the Regulations. The Company has made capital expenditures of less
than $3.8 million in each of the last three years in order to comply with the
Regulations (which expenditures are included in additions to property, plant and
equipment) and anticipates that aggregate capital expenditures relating to
environmental compliance in 1996 and 1997 will be approximately $3.4 million and
$3.5 million, respectively.
 
   
     The Regulations deal with air and water emissions or discharges into the
environment, as well as the generation, storage, treatment, transportation and
disposal of solid and hazardous waste, and the remediation of any releases of
hazardous substances and materials to the environment. The Company believes that
its manufacturing facilities comply in all material respects with applicable
Regulations, and, while it cannot predict whether more burdensome requirements
will be adopted in the future, it believes that any potential liability for
compliance with the Regulations will not materially affect its business,
liquidity, results of operations, cash flows or financial position.
    
 
     The Company believes that its manufacturing facilities are being operated
in compliance in all material respects with applicable environmental, health and

safety laws and regulations but cannot predict whether more burdensome
requirements will be imposed by governmental authorities in the future.
 
ENVIRONMENTAL LITIGATION
 
     The Company, together with other companies, is a party to a variety of
proceedings and lawsuits involving environmental matters ('Environmental
Claims') under the Comprehensive Environmental Response Compensation and
Liability Act ('CERCLA') and similar state laws, in which recovery is sought for
the cost of cleanup of contaminated sites, a number of which are in the early
stages or have been dormant for protracted periods.
 
                                       46
<PAGE>
   
     The Company estimates that its liability in respect of all Environmental
Claims, and certain other environmental compliance expenses, as of September 29,
1996, after giving effect to the Transactions will be $17.4 million, before
reduction for insurance recoveries reflected on its balance sheet (discussed
below) of $6.9 million ('estimated recoveries'). In the opinion of management,
the resolution of such matters should not be material to the business,
liquidity, results of operations, cash flows or financial position of the
Company. However, adverse decisions or events, particularly as to the liability
and the financial responsibility of the Company's insurers and of the other
parties involved at each site and their insurers, could cause the Company to
increase its estimate of its liability in respect of such matters. It is not
currently possible to estimate the amount or range of any additional liability.
    
 
     After considering the relevant legal issues and other pertinent factors,
the Company believes that it will receive the estimated recoveries and it may
receive amounts substantially in excess thereof. The Company believes it is
entitled to substantially full defense and indemnity under its insurance
policies for most Environmental Claims, although the Company's insurers have not
affirmed a legal obligation under the policies to provide indemnity for such
claims.
 
     The estimated recoveries are based in part upon interim agreements with
certain insurers. The Company terminated these agreements in 1995 and on March
8, 1995 commenced litigation in the United States District Court for the
District of New Jersey seeking amounts substantially in excess of the estimated
recoveries. While the Company believes that its claims are meritorious, there
can be no assurance that the Company will prevail in its efforts to obtain
amounts equal to, or in excess of, the estimated recoveries.
 
     In June 1989, ISP entered into a Consent Order with the New Jersey
Department of Environmental Protection ('NJDEP') requiring the development of a
remediation plan for its closed Linden, New Jersey plant and the maintenance of
financial assurances (currently $7.5 million) to guarantee ISP's performance. In
April 1993, NJDEP issued orders which require the prevention of discharge of
contaminated groundwater and stormwater from the site and the elimination of
other potential exposure concerns. ISP believes, although there can be no
assurance, that, taking into account its plans for development of the site, it
can comply with the NJDEP order at a cost of no more than $7.5 million (in

connection with which ISP anticipates insurance recoveries of approximately $5
million). See '--Environmental Services.'
 
     Pursuant to an Order dated September 28, 1990 issued by the United States
Environmental Protection Agency (the 'EPA'), over 100 potentially responsible
parties, including the Company, have agreed to participate in the remediation of
a contaminated waste disposal site in Carlstadt, New Jersey. The EPA is
evaluating final remedies for the site. Total cleanup costs are unknown but the
Company estimates, based on information currently available to it, that the
insurance described above will cover a substantial portion of the Company's
share of such costs.
 
EMPLOYEES
 
     ISP Holdings has no employees other than its officers.
 
     At September 29, 1996, ISP Holdings and its subsidiaries employed
approximately 2,700 people worldwide and approximately 700 employees in the
United States and Canada were subject to 6 union contracts. The Company does not
expect to renegotiate any additional labor contracts during the remainder of
1996. The Company believes that its relations with its employees and their
unions are satisfactory.
 
     The Company has in effect various benefit plans, which include a
non-qualified retirement plan for a group of executives, a capital accumulation
plan for its salaried and certain hourly employees, a flexible benefit plan for
its salaried employees, a retirement plan for certain of its hourly employees,
and group insurance agreements providing life, accidental death, disability,
hospital, surgical, medical and dental coverage. In addition, the Company has
contracted with various health maintenance organizations to provide medical
benefits. The Company and, in many cases, its employees contribute to the cost
of these plans.
 
                                       47

<PAGE>
                                   MANAGEMENT
 
     The following table sets forth the name, age, position and other
information with respect to the directors and executive officers of ISP
Holdings. Each person listed below is a citizen of the United States.
 
<TABLE>
<CAPTION>
                                                      PRESENT PRINCIPAL OCCUPATION OR EMPLOYMENT
NAME AND POSITION HELD(1)                AGE               AND FIVE-YEAR EMPLOYMENT HISTORY
- --------------------------------------   ---   ---------------------------------------------------------
<S>                                      <C>   <C>
Samuel J. Heyman
  Director, Chairman and
  Chief Executive Officer.............   57    Mr. Heyman has been a director and Chairman and Chief
                                                 Executive Officer of ISP Holdings since its formation,
                                                 of G-I Holdings since August 1988 and of GAF, G
                                                 Industries and certain of its subsidiaries since April
                                                 1989, prior to which he held the same position with the
                                                 predecessor to GAF (the 'Predecessor Company') from
                                                 December 1983 to April 1989. Mr. Heyman has been
                                                 Chairman and Chief Executive Officer of ISP, and has
                                                 been a director and Chairman of BMCA, since their
                                                 respective formations. Mr. Heyman has been a director
                                                 of USI since October 1995 and Chief Executive Officer
                                                 of BMCA since June 1996. He is also the Chief Executive
                                                 Officer, Manager and General Partner of a number of
                                                 closely held real estate development companies and
                                                 partnerships whose investments include commercial real
                                                 estate and a portfolio of publicly traded securities.
Peter R. Heinze
  President and Chief
  Operating Officer,
  International
  Specialty
  Products Inc........................   55    Dr. Heinze has been President, Chief Operating Officer
                                                 and a Director of ISP since November 1996. He was
                                                 Senior Vice President, Chemicals of PPG Industries,
                                                 Inc. from April 1993 to November 1996 and Group Vice
                                                 President, Chemicals of PPG Industries, Inc. from
                                                 August 1992 to April 1993. From January 1988 to August
                                                 1992, Dr. Heinze was President, Chemicals Division, and
                                                 an Executive Vice President of BASF Corporation.
Carl R. Eckardt
  Executive Vice President............   65    Mr. Eckardt has been Executive Vice President of ISP
                                                 Holdings since its formation. He has been Vice Chairman
                                                 of GAF since November 1996 and a director of GAF since
                                                 April 1987. He was Executive Vice President of GAF from
                                                 April 1989 to November 1996 and held the same position
                                                 with the Predecessor Company from January 1987 to April
                                                 1989. He was President and Chief Operating Officer of
                                                 ISP from January 1994 to November 1996 and was
                                                 Executive Vice President of ISP from its formation to

                                                 January 1994 and has served as such since November
                                                 1996. Mr. Eckardt has been
</TABLE>
 
                                       48
<PAGE>
   
<TABLE>
<CAPTION>
                                                      PRESENT PRINCIPAL OCCUPATION OR EMPLOYMENT
NAME AND POSITION HELD(1)                AGE               AND FIVE-YEAR EMPLOYMENT HISTORY
- --------------------------------------   ---   ---------------------------------------------------------
<S>                                      <C>     <C>
                                                 Executive Vice President of G-I Holdings since March
                                                 1993. Mr. Eckardt was President of GCC and the
                                                 Predecessor Company's chemicals division from 1985 to
                                                 1987. Mr. Eckardt was a Senior Vice President Worldwide
                                                 Chemicals and Senior Vice President International
                                                 Chemicals of the Predecessor Company from 1982 to 1985
                                                 and 1981 to 1982, respectively. Mr. Eckardt joined the
                                                 Predecessor Company in 1974.
James P. Rogers
  Executive Vice President and
  Chief Financial Officer.............   45    Mr. Rogers has been Executive Vice President and Chief
                                                 Financial Officer of ISP Holdings, G-I Holdings, GAF
                                                 and certain of its subsidiaries, Executive Vice
                                                 President of BMCA and Executive Vice President-Finance
                                                 of ISP since December 1996. He was Senior Vice
                                                 President of such corporations from November 1993 to
                                                 December 1996 and of BMCA from its formation to
                                                 December 1996. Mr. Rogers has been a director and
                                                 Senior Vice President of USI since October 1995. Mr.
                                                 Rogers has served as Treasurer of G-I Holdings, GAF and
                                                 certain of its subsidiaries since March 1992 and was
                                                 Vice President-Finance of such corporations from March
                                                 1992 to October 1993. He was Treasurer of ISP from
                                                 March 1992 to December 1994 and from September 1995 to
                                                 December 1996. From August 1987 to March 1992, Mr.
                                                 Rogers was Treasurer of Amphenol Corporation, a
                                                 manufacturer of electronic connectors.

Richard A. Weinberg
  Senior Vice President and
  General Counsel.....................   37    Mr. Weinberg has been Senior Vice President and General
                                                 Counsel of ISP Holdings since its formation, and of
                                                 GAF, G-I Holdings, ISP, BMCA and certain of their
                                                 subsidiaries since May 1996. He was Vice President and
                                                 General Counsel of BMCA from September 1994 to May
                                                 1996, Vice President Law of BMCA from May 1994 to
                                                 September 1994 and Vice President Law of GAFBMC from
                                                 April 1993 to May 1994. Mr. Weinberg was employed by
                                                 Reliance Group Holdings Inc., a diversified insurance
                                                 holding company, as Staff Counsel from October 1987 to
                                                 January 1990 and as Assistant Vice President and
                                                 Corporate Counsel from January 1990 to April 1993.

Louis S. Goldberg
  Senior Vice President,
  Corporate Human Resources...........   59    Mr. Goldberg has been Senior Vice President, Corporate
                                                 Human Resources of ISP Holdings since
</TABLE>
    
 
                                       49
<PAGE>
<TABLE>
<CAPTION>
                                                      PRESENT PRINCIPAL OCCUPATION OR EMPLOYMENT
NAME AND POSITION HELD(1)                AGE               AND FIVE-YEAR EMPLOYMENT HISTORY
- --------------------------------------   ---   ---------------------------------------------------------
<S>                                            <C>
                                                 its formation and of GAF and G-I Holdings and certain
                                                 of their subsidiaries since July 1996. He has served as
                                                 Senior Vice President, Headquarters Administrative
                                                 Services of ISP since July 1996. From January 1996 to
                                                 July 1996, Mr. Goldberg served as a senior consultant
                                                 to GAF. From January 1995 to January 1996, he was
                                                 Commissioner of the Department of Administrative
                                                 Services for the State of Connecticut, and from January
                                                 1991 to December 1993 he served as Connecticut's
                                                 Commissioner of the Department of Motor Vehicles. From
                                                 September 1989 to December 1990, he was Senior Vice
                                                 President of Staub, Warmbold & Associates. From August
                                                 1984 to April 1989 he was Vice President-Human
                                                 Resources of Playtex, Inc. and from February 1977 to
                                                 January 1984 he was Vice President Administration/Human
                                                 Resources of The Seagram Company Ltd.
</TABLE>
 
- ------------------
   
(1) Under ISP Holdings' By-laws, each director and executive officer continues
    in office until ISP Holdings' next annual meeting of stockholders and until
    his or her successor is elected and qualified.
    
 
                                       50

<PAGE>
                             EXECUTIVE COMPENSATION
 
     No compensation is paid to officers or directors of ISP Holdings for their
services in such capacity.
 
SUMMARY COMPENSATION TABLE
 
     The following table sets forth the cash and noncash compensation for each
of the last three fiscal years awarded to or earned by the Chief Executive
Officer of ISP Holdings and the four other most highly compensated executive
officers of ISP Holdings who were employed in such capacity as of December 31,
1995.
 
<TABLE>
<CAPTION>
                                          ANNUAL COMPENSATION                            LONG-TERM COMPENSATION
                              --------------------------------------------    --------------------------------------------
NAME AND PRINCIPAL                                            OTHER ANNUAL             SECURITIES              ALL OTHER
POSITION(1)                   YEAR     SALARY     BONUS(2)    COMPENSATION     UNDERLYING OPTIONS/SARS(4)     COMPENSATION
- ----------------------------  ----    --------    --------    ------------    -----------------------------   ------------
<S>                           <C>     <C>         <C>         <C>             <C>                             <C>
Samuel J. Heyman............  1995    $553,666    $200,000             0          150,000 (O)                   $  9,848(3)
  Chairman of the             1994     394,792           0             0                   0                      23,665(3)
  Board of Directors          1993     464,792           0             0                   0                      12,750(3)
  and Chief Executive
  Officer
Carl R. Eckardt.............  1995     325,500     300,000             0           41,600                         10,095(3)
  President and               1994     312,084     300,000             0           45,240 (O)                     15,440(3)
  Chief Operating             1993     269,583     100,000             0                   0                       8,064(3)
  Officer, ISP
Mark A. Buckstein(5)........  1995     321,563     135,000             0           35,700 (O)                     17,920(5)
  Executive Vice              1994     306,250     185,000      $ 60,289(5)         2,993 (S)                     24,430(5)
  President, General          1993     125,000(5)   65,000(5)     35,000(5)        30,000 (O)/6,255(S)             4,685(5)
  Counsel and Secretary
James P. Rogers.............  1995     248,333     225,000             0           38,300 (O)                     13,154(6)
  Senior Vice President       1994     224,167     200,000             0           15,000 (O)                     18,025(6)
  and Chief                   1993     194,167     200,000             0           15,000 (O)/9,319(S)            21,903(6)
  Financial Officer
 
James J. Strupp.............  1995     204,667      47,500         5,055           14,000 (O)                      3,766(7)
  Senior Vice President,      1994     188,542      37,500         4,079           15,180 (O)/3,026(S)             7,746(7)
  Human Resources             1993     167,292      25,000         3,848           17,123 (O)/6,202(S)             5,537(7)
</TABLE>
 
- ------------------
(1) ISP paid the compensation to each of such named executive officers. The SARs
    were granted by GAF.
 
(2) Bonus amounts are payable pursuant to ISP's Executive Incentive Compensation
    Programs.
 
(3) Included in these amounts for Mr. Heyman are: $8,598, $22,415 and $11,000
    for the premium paid by the Company for a life insurance policy in 1995,

    1994 and 1993, respectively; and $1,250, $1,250 and $1,750 for the premium
    paid by the Company for a long-term disability policy in 1995, 1994 and
    1993, respectively. Included in these amounts for Mr. Eckardt are: $8,845,
    $14,190 and $6,314 for the premium paid by G-I Holdings for a life insurance
    policy in 1995, 1994 and 1993, respectively; and $1,250, $1,250 and $1,750
    for the premiums paid by the Company for a long-term disability policy in
    1995, 1994 and 1993, respectively.
 
(4) The options (O) are for shares of ISP Common Stock and the stock
    appreciation rights (S) relate to shares of GAF common stock. See 'Options
    and Stock Appreciation Rights.'
 
(5) Mr. Buckstein commenced employment as Executive Vice President, General
    Counsel and Secretary on August 1, 1993 and retired from the Company on May
    15, 1996. Included in 'Other Annual Compensation' for Mr. Buckstein are
    $31,398 in payment of moving related expenses and a 'tax gross-up' of
    $21,440 in 1994 and $35,000 in payment of moving related expenses in 1993,
    all in connection with Mr. Buckstein's move following his joining the
    Company. Included in 'All Other Compensation' for Mr. Buckstein are: $11,000
    and $11,000, representing the Company's contribution under the GAF Capital
    Accumulation Plan in 1995 and 1994, respectively; $5,670, $12,180 and $2,935
                                 for the premium paid by G-I Holdings for a life
 
                                              (Footnotes continued on next page)
 
                                       51
<PAGE>
(Footnotes continued from previous page)
    insurance policy in 1995, 1994 and 1993, respectively; and $1,250, $1,250
    and $1,750 for the premium paid by the Company for a long-term disability
    policy in 1995, 1994 and 1993, respectively.
 
(6) Included in these amounts for Mr. Rogers are $10,963, $10,750 and $16,040,
    representing the Company's contribution under the GAF Capital Accumulation
    Plan in 1995, 1994 and 1993, respectively; $978, $6,125 and $4,504 for the
    premium paid by the Company for a life insurance policy in 1995, 1994 and
    1993, respectively; and $1,213, $1,150 and $1,359 for the premium paid by
    the Company for a long-term disability policy in 1995, 1994 and 1993,
    respectively.
 
(7) Included in these amounts for Mr. Strupp are $500, $500 and $500,
    representing the Company's contribution under the GAF Capital Accumulation
    Plan in 1995, 1994 and 1993, respectively; $2,266, $6,383 and $3,866 for the
    premium paid by the Company for a life insurance policy in 1995, 1994 and
    1993, respectively; and $1,000, $863 and $1,171 for the premium paid by the
    Company for a long-term disability policy in 1995, 1994 and 1993,
    respectively.
 
OPTIONS AND STOCK APPRECIATION RIGHTS
 
     The following tables summarize grants of options to acquire ISP Common
Stock granted during 1995 to the executive officers named in the Summary
Compensation Table above and the potential realizable value of such options and
stock appreciation rights ('SARs') relating to GAF common stock held by such

persons. No SARs were granted to, and no options or SARs were exercised by, such
persons in 1995.
 
                     ISP COMMON STOCK OPTION GRANTS IN 1995
 
<TABLE>
<CAPTION>
                                                                                                        POTENTIAL REALIZABLE
                                                                                                          VALUE AT ASSUMED
                                                                                                           ANNUAL RATES OF
                                      NUMBER OF      % OF TOTAL                                              STOCK PRICE
                                      SECURITIES      OPTIONS       EXERCISE/    MARKET                   APPRECIATION FOR
                                      UNDERLYING     GRANTED TO       BASE       PRICE                       OPTION TERM
                                       OPTIONS       EMPLOYEES        PRICE     ON DATE    EXPIRATION   ---------------------
NAME                                  GRANTED(0)   IN FISCAL 1995   ($/SHARE)   OF GRANT      DATE         5%         10%
- ------------------------------------  ----------   --------------   ---------   --------   ----------   --------   ----------
<S>                                   <C>          <C>              <C>         <C>        <C>          <C>        <C>
Samuel J. Heyman....................    150,000(2)      11.07%       $ 7.000    $  7.000     2/27/04    $578,850   $1,425,900
Carl R. Eckardt.....................     41,600(3)       3.07%         8.625       8.625     7/10/04     197,808      487,219
Mark A. Buckstein...................     35,700(3)       2.63%         8.625       8.625     7/10/04     169,754      418,118
James P. Rogers.....................     25,800(4)       1.90%         8.625       8.625     7/10/04     122,679      302,170
                                         12,500(4)       0.92%         5.875      10.875    12/31/01     108,732      167,384
James J. Strupp.....................     14,000(3)       1.03%         8.625       8.625     7/10/04      66,570      163,968
</TABLE>
 
- ------------------
   
(1) Options were granted under the ISP 1991 Incentive Plan for Key Employees and
    Directors, as amended (the '1991 Incentive Plan'). Each option becomes
    vested as to 20%, 40%, 60%, 80% and 100% of the shares subject thereto on
    each of the first through the fifth anniversaries of the date of grant,
    respectively, and, to the extent vested, is exercisable for 9 years from the
    date of grant, except for options granted to Mr. Rogers for 12,500 shares
    which will become fully vested 2 1/2 years after the date of grant, and, to
    the extent vested, are exercisable for 6 years from the date of grant. The
    Compensation and Pension Committee of the Board of Directors of ISP may, on
    a case by case basis, accelerate the vesting of unvested options in the
    event of a 'Change in Control' (as defined). The consummation of the
    Transactions did not result in a Change in Control under the 1991 Incentive
    Plan.
    
 
(2) Mr. Heyman's ISP options were granted on February 27, 1995 and became or
    will become exercisable as to 30,000 shares on each of February 27, 1996,
    1997, 1998, 1999 and 2000.
 
(3) Mr. Eckardt's, Mr. Buckstein's and Mr. Strupp's ISP options were granted on
    July 10, 1995. Mr. Eckardt's and Mr. Strupp's options will become
          exercisable as to 8,320 shares and 2,800 shares, respectively, on each
 
                                              (Footnotes continued on next page)
 
                                       52
<PAGE>

(Footnotes continued from previous page)
    of July 10, 1996, 1997, 1998, 1999 and 2000. Mr. Buckstein's options
    terminated upon his retirement from the Company.
 
(4) Mr. Rogers' options for 25,800 shares were granted on July 10, 1995 and will
    become exercisable as to 5,160 shares on each of July 10, 1996, 1997, 1998,
    1999 and 2000. Mr. Rogers' options for 12,500 ISP shares will become
    exercisable on June 30, 1998.
 
VALUE OF ISP COMMON STOCK OPTIONS/GAF STOCK APPRECIATION RIGHTS AT DECEMBER 31,
                                      1995
 
<TABLE>
<CAPTION>
                                     NUMBER OF SECURITIES UNDERLYING      VALUE OF UNEXERCISED
                                     UNEXERCISED ISP OPTIONS (O)/GAF    IN-THE-MONEY OPTION/SARS
                                           SARS(S) AT 12/31/95               AT 12/31/95(1)
               NAME                     EXERCISABLE/UNEXERCISABLE       EXERCISABLE/UNEXERCISABLE
- ----------------------------------   -------------------------------    ------------------------
<S>                                  <C>                                <C>
Samuel J. Heyman..................                0/150,000(O)              $     0/$581,250
Carl R. Eckardt...................            39,048/97,792(O)                37,323/242,892
Mark A. Buckstein.................            12,000/53,700(O)                49,500/154,575
                                                    0/9,248(S)                     0/359,662
James P. Rogers...................            27,000/71,300(O)                25,875/190,300
                                                    0/9,319(S)                     0/312,122
James J. Strupp...................             9,885/36,418(O)                40,776/118,119
                                                    0/9,228(S)                     0/315,184
</TABLE>
 
- ------------------
 
(1) Options for 150,000, 86,840, 65,700, 68,300 and 46,303 shares were
    in-the-money for Messrs. Heyman, Eckardt, Buckstein, Rogers and Strupp,
    respectively, as of December 31, 1995. All outstanding SARs were
    in-the-money as of December 31, 1995.
 
PENSION PLANS
 
     Non-Qualified Retirement Plan.  The Company has a non-qualified retirement
plan for the benefit of certain key employees (the 'Retirement Plan'). The
benefit payable under the Retirement Plan, which vests in accordance with a
10-year schedule, consists of an annual payment commencing at age 65 equal to
25% of a covered employee's last full year's base salary. The benefit continues
for the longer of 15 years or the joint lifetimes of the employee or his or her
spouse. If a covered employee dies while employed by GAF or a subsidiary, a
death benefit of 36% of the employee's base salary at the date of death is
payable for a term of 15 years to the employee's beneficiary.
 
     No new participants have been admitted to the Retirement Plan since January
1989 and it is not anticipated that any new participants will be admitted
hereafter. Of the executive officers named in the Summary Compensation Table,
only Messrs. Heyman, Eckardt and Strupp participate in the Retirement Plan.
 

     The following table shows, for the salary levels and years of service
indicated, the annual pension benefit, payable commencing at age 65 to
participants in the Retirement Plan.
 
                                       53
<PAGE>
                         NON-QUALIFIED RETIREMENT PLAN
                           ANNUAL PAYMENTS AT AGE 65
 
<TABLE>
<CAPTION>
                                                       YEARS OF SERVICE
                        -------------------------------------------------------------------------------
             SALARY        5          10          15          20          25          30          35
            --------    -------    --------    --------    --------    --------    --------    --------
<S>         <C>         <C>        <C>         <C>         <C>         <C>         <C>         <C>
            $250,000    $31,250    $ 62,500    $ 62,500    $ 62,500    $ 62,500    $ 62,500    $ 62,500
             300,000     37,500      75,000      75,000      75,000      75,000      75,000      75,000
             350,000     43,750      87,500      87,500      87,500      87,500      87,500      87,500
             400,000     50,000     100,000     100,000     100,000     100,000     100,000     100,000
             450,000     56,250     112,500     112,500     112,500     112,500     112,500     112,500
             500,000     62,500     125,000     125,000     125,000     125,000     125,000     125,000
             550,000     68,750     137,500     137,500     137,500     137,500     137,500     137,500
             600,000     75,000     150,000     150,000     150,000     150,000     150,000     150,000
             650,000     81,250     162,500     162,500     162,500     162,500     162,500     162,500
             700,000     87,500     175,000     175,000     175,000     175,000     175,000     175,000
</TABLE>
 
     The years of service covered by the Retirement Plan are, for Mr. Heyman,
Mr. Eckardt and Mr. Strupp, nine years, nine years and seven years,
respectively. Current salaries covered by the Retirement Plan are the amounts
set forth under the 'salary' column of the Summary Compensation Table for the
above-named executive officers. The annual pension benefit is not subject to
reduction for Social Security and other benefits and is computed on a
straight-life annuity basis.
 
     Additional Pension Arrangements.  ISP has agreed to provide Mr. Eckardt, at
age 67, a $200,000 annuity comprising two pieces: (i) the benefits payable under
the Retirement Plan described above, and (ii) a supplemental retirement benefit
representing the difference between $200,000 per year and the benefit payable
under the Retirement Plan. The supplemental retirement benefit will vest at 20%
per year over a five year period beginning March 19, 1994. In the event Mr.
Eckardt should die without a surviving spouse, no supplemental retirement
benefit will be payable. In the event Mr. Eckardt should die prior to the
termination of his employment, and leave a surviving spouse, his spouse will be
entitled to receive for her life an annual payment of the portion of the
supplemental retirement benefit in which he was vested on the date of his death.
If Mr. Eckardt's employment is terminated involuntarily other than for cause (as
defined), or in the event Mr. Eckardt becomes totally and permanently disabled,
he will be entitled to receive payment of the portion of the supplemental
retirement benefit in which he is vested on the date of termination or of the
onset of such disability. If Mr. Eckardt's employment is terminated for cause,
the Company in its sole discretion may declare all or any portion (whether
vested or unvested) of the supplemental retirement benefits forfeited.

 
                                       54

<PAGE>
         SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
 
ISP HOLDINGS
 
     Prior to consummation of the Spin Off Transactions, all of the outstanding
common stock of ISP Holdings ('ISP Holdings Common Stock') was owned of record
by GAF. As part of the Spin Off Transactions, the ISP Holdings Common Stock was
distributed to the stockholders of GAF initially in the same proportion as they
own common stock of GAF. See 'The Spin Off Transactions.'
 
   
     The following table sets forth information with respect to the ownership of
ISP Holdings Common Stock, as of January 31, 1997, by each other person known to
ISP Holdings to own beneficially more than 5% of the ISP Holdings Common Stock
outstanding on that date, by each director of ISP Holdings and by all executive
officers and directors of ISP Holdings as a group, based on 10 shares of ISP
Holdings Common Stock outstanding on that date:
    
    
<TABLE>
<CAPTION>
                                                              AMOUNT AND
                                                              NATURE OF                    PERCENT OF
                                 NAME AND ADDRESS OF          BENEFICIAL    PERCENT OF    TOTAL VOTING
TITLE OF CLASS                     BENEFICIAL OWNER           OWNERSHIP       CLASS          POWER
- -------------------------  --------------------------------   ----------    ----------    ------------
<S>                        <C>                                <C>           <C>           <C>
Common Stock.............  Samuel J. Heyman                   1,701,100(1)       96%(1)         96%(1)
                           1361 Alps Road
                           Wayne, New Jersey 07470
                           All directors and executive        1,731,095(1)       98%(1)         98%(1)
                           officers of ISP Holdings as
                           a group (6 persons)
</TABLE>
     
- ------------------
(1) By virtue of Mr. Heyman's ownership of capital stock of GAF having
    approximately 96% of the combined voting power thereof, Mr. Heyman may be
    deemed to be the beneficial owner of all shares of ISP Holdings Common
    Stock.
 
ISP
 
   
     As of January 31, 1997, shares of ISP Common Stock were beneficially owned
by ISP Holdings' directors, ISP Holdings and ISP Holdings' directors and
executive officers as a group as follows:
    
 
<TABLE>
<CAPTION>
                                          NUMBER OF             NUMBER OF SHARES
                                            SHARES                BENEFICIALLY      BENEFICIAL

NAME                                        OWNED        %          OWNED(3)           %(3)
- ---------------------------------------   ----------    ----    ----------------    ----------
<S>                                       <C>           <C>     <C>                 <C>
Samuel J. Heyman.......................      125,000     0.1%      80,655,000(1)       83.6%(1)
Carl R. Eckardt(2).....................        1,000       *           77,416             *
James P. Rogers........................       20,316(4)    *           67,477(4)          *
Peter R. Heinze........................            0       *                0             *
Louis S. Goldberg......................          200       *              200             *
Richard A. Weinberg....................            0       *                0             *
ISP Holdings...........................   80,500,000    83.5%      80,500,000          83.5%
All directors and executive officers
  of ISP Holdings (6 persons)..........      146,516(4)  0.2(3)(4) 80,800,092(2)(4)    83.7%(2)(4)
</TABLE>
 
- ------------------
 * Less than one-tenth of one percent
 
   
(1) By virtue of Mr. Heyman's ownership of capital stock of ISP Holdings having
    approximately 96% of the combined voting power thereof, the number of shares
    shown as being beneficially owned by Mr. Heyman includes 80,500,000 shares
    owned by ISP Holdings. The business addresses of Mr. Heyman and ISP Holdings
    are 1361 Alps Road, Wayne, New Jersey 07470 and 818 Washington Street,
    Wilmington, Delaware 19801, respectively.
    
 
                                              (Footnotes continued on next page)
 
                                       55
<PAGE>
(Footnotes continued from previous page)
 
(2) The number of shares shown as being beneficially owned by all directors and
    officers of ISP Holdings as a group attributes ownership of ISP Holdings'
    80,500,000 shares to Mr. Heyman. See footnote 1 above. Mr. Eckardt also owns
    29,995 shares of GAF's common stock which shares have, in the aggregate,
    approximately 1.7% of the combined voting power of GAF's capital stock. Such
    shares are held subject to GAF's right to acquire such shares from Mr.
    Eckardt upon his termination of employment with GAF and its affiliates.
 
(3) Includes with respect to Messrs. Heyman, Eckardt and Rogers and all
    directors and executive officers as a group 30,000, 76,416, 47,160 and
    153,576 shares, respectively, subject to options granted under the ISP 1991
    Incentive Plan which are currently exercisable or exercisable within 60
    days.
 
(4) Includes with respect to Mr. Rogers 7,316 shares held in his account with
    the GAF Capital Accumulation Plan as of December 31, 1995 and 10,000 shares
    held jointly with his spouse.
 
                             TAX SHARING AGREEMENT
 
   
     Effective January 1, 1997, ISP and its domestic subsidiaries entered into a

Tax Sharing Agreement with ISP Holdings with respect to the payment of federal
income taxes and certain related matters (the 'ISP Holdings Tax Sharing
Agreement'). During the term of the ISP Holdings Tax Sharing Agreement, which
extends as long as ISP or any of its domestic subsidiaries, as the case may be,
is included in a consolidated federal income tax return filed by ISP Holdings,
or a successor entity, ISP is obligated to pay to ISP Holdings an amount equal
to those federal income taxes ISP would have incurred if, subject to certain
exceptions, ISP (on behalf of itself and its domestic subsidiaries) filed its
consolidated federal income tax return. These exceptions include, among others,
that ISP may utilize certain favorable tax attributes i.e., losses, deductions
and credits (except for a certain amount of foreign tax credits and, in general,
net operating losses) only at the time such attributes reduce the federal income
tax liability of ISP Holdings and its consolidated subsidiaries (the 'ISP
Holdings Group'); and that ISP may carry back or carry forward its favorable tax
attributes only after taking into account current tax attributes of the ISP
Holdings Group. In general, subject to the foregoing limitations, unused tax
attributes carry forward for use in reducing amounts payable by ISP to ISP
Holdings in future years. Subject to certain exceptions, actual payment for such
attributes will be made by ISP Holdings to ISP only when ISP Holdings receives
an actual refund of taxes from the IRS or, under certain circumstances, the
earlier of (i) the dates of the filing of federal income tax returns of ISP for
taxable years of ISP following the last taxable year in which it was a member of
the ISP Holdings Group, or (ii) when ISP Holdings no longer owns more than 50%
of ISP. Foreign tax credits not utilized by ISP in computing its tax sharing
payments will be refunded by ISP Holdings to ISP, if such credits expire
unutilized, upon the termination of the statute of limitations for the year of
expiration.
    
 
     The ISP Holdings Tax Sharing Agreement provides for analogous principles to
be applied to any consolidated, combined or unitary state or local income taxes.
Under the ISP Holdings Tax Sharing Agreement, ISP Holdings makes all decisions
with respect to all matters relating to taxes of the ISP Holdings Group. The
provisions of the ISP Holdings Tax Sharing Agreement take into account both the
federal income taxes ISP would have incurred if it filed its own separate
federal income tax return and the fact that ISP is a member of the ISP Holdings
Group for federal income tax purposes.
 
     ISP Holdings and ISP were parties to tax sharing agreements with members of
the GAF Group. As a result of the Spin Off Transactions, ISP Holdings and ISP
are no longer included in the consolidated federal income tax returns of GAF,
and therefore, such tax sharing agreements are no longer applicable with respect
to the future tax liabilities of ISP Holdings and ISP. ISP Holdings and ISP
remain obligated, however, with respect to tax liabilities imposed or that may
be imposed for periods prior to the Spin Off Transactions. Among other things,
those tax sharing agreements provide for the sharing of the GAF Group's
consolidated tax liability based on each member's share of the tax as if such
member filed on a separate basis. Accordingly, a payment of tax would be made to
GAF equal to ISP Holdings' and ISP's allocable share of the GAF Group's
consolidated tax liability. Alternatively, ISP Holdings and ISP would be
entitled to refunds if losses or other attributes reduce the GAF Group's
consolidated tax liability. Moreover, foreign tax credits generated by ISP not
utilized by GAF will be refunded by GAF or its subsidiary to ISP, if such
credits expire unutilized upon termination of the statute of limitations for the

year of expiration. Furthermore, those tax sharing agreements provide for an
indemnification to ISP Holdings and ISP for any tax liability attributable to
another member of the GAF Group.
 
     See 'Certain Relationships' for information relating to tax indemnification
in connection with the Spin Off Transactions.
 
                                       56
<PAGE>
                             CERTAIN RELATIONSHIPS
 
   
     Management Agreement.  Pursuant to a Management Agreement (the 'Management
Agreement') which expires at the end of 1997, ISP provides certain general
management, administrative and facilities services to ISP Holdings and to
certain other affiliates of GAF, including BMCA, USI, G-I Holdings and GCC.
Charges by ISP for providing such services aggregated $4.9 million in 1996. In
addition to the management services charge, BMCA paid approximately $800,000 to
ISP in 1996, primarily for telecommunications and information services, and ISP
Holdings, G-I Holdings and BMCA paid approximately $500,000 to ISP in 1996 for
legal services, which in each case were not then contemplated by the Management
Agreement. In connection with the Spin Off Transactions, the Management
Agreement was modified to incorporate such services, and, in that connection,
the total charges for management fees were increased to an annual rate of $5.5
million, effective January 1, 1997. Although, due to the unique nature of the
services provided under the Management Agreement, comparisons with third party
arrangements are difficult, ISP believes that the terms of the Management
Agreement, taken as a whole, are no less favorable to ISP than could be obtained
from an unaffiliated third party. Certain of the executive officers of ISP
perform services for affiliates of ISP pursuant to the Management Agreement, and
ISP is indirectly reimbursed therefor by virtue of the management fee.
    
 
   
     Granules Contracts.  BMCA purchases from ISP all of its colored roofing
granule requirements (except for the requirements of BMCA's California roofing
plant) under a requirements contract which was renewed for 1997 and is subject
to annual renewal unless terminated by ISP or BMCA. In addition, in December
1995, USI commenced purchasing from ISP substantially all of its requirements
for colored roofing granules (except for the requirements of USI's Stockton,
California and Corvallis, Oregon plants) pursuant to a requirements contract
which expires December 31, 1997. In 1996, BMCA and USI purchased approximately
$50.5 million of mineral products from ISP, representing approximately 7% of
ISP's total net sales and approximately 59% of ISP's net sales of mineral
products. The Company's supply arrangements with BMCA and USI are at prices and
on terms which the Company believes are no less favorable to ISP than could be
obtained from an unaffiliated third party.
    
 
   
     Mutual Indemnification.  Pursuant to the terms of an indemnification
agreement dated as of October 18, 1996 (the 'Indemnification Agreement') among
GAF, G-I Holdings, ISP Holdings, G Industries and GFC, (i) GAF and G-I Holdings
have agreed to indemnify ISP Holdings and its subsidiaries for all liabilities

of the GAF Group as it is currently comprised (the 'Current GAF Group'),
including all liabilities for asbestos-related claims (whether for indemnity or
defense) and such group's liabilities relating to environmental matters,
litigation and employee benefits and excluding all liabilities of ISP and its
subsidiaries, all liabilities relating to the Notes and all other liabilities
reflected in the pro forma consolidated balance sheet of ISP Holdings and its
subsidiaries or the notes thereto prepared in connection with the ISP Holdings
Transactions, (ii) ISP Holdings has agreed to indemnify GAF and the other
members of the Current GAF Group for all liabilities of ISP and its
subsidiaries, all liabilities relating to the Notes, and all other liabilities
reflected in the pro forma consolidated balance sheet of ISP Holdings and its
subsidiaries or the notes thereto prepared in connection with the ISP Holdings
Transactions (excluding those liabilities as to which ISP Holdings is being
indemnified in accordance with clause (i)), (iii) ISP Holdings has agreed to
indemnify GAF and the other members of the Current GAF Group for its accrued tax
liability prior to the Spin Off Transactions and (iv) GAF, G-I Holdings, G
Industries and GFC have agreed to indemnify ISP Holdings, ISP and its
subsidiaries from, and against, any and all taxes (net of any tax benefits
realized by the indemnitees) that may be payable by the Current GAF Group with
respect to the Spin Off Transactions. See 'Selected Financial Data.'
    
 
   
     Affiliate Borrowings.  Prior to the consummation of the Spin Off
Transactions, letters of credit for the benefit of BMCA and G-I Holdings were
provided under the ISP Credit Agreement. The highest amount of such letters of
credit during 1996 was $2.3 million. In addition, prior to the consummation of
the Spin Off Transactions, ISP Holdings and ISP and its subsidiaries borrowed
from G-I Holdings from time to time at prevailing market rates (between 5.7% and
6.0% per annum during 1996). The highest amount of loans made by G-I Holdings
during 1996 was $153 million. As of December 31, 1996, no amounts were owed by
ISP Holdings, ISP or its subsidiaries to G-I Holdings.
    
 
     Other Transactions Between ISP Holdings and Other Members of the Current
GAF Group.  The Indentures restrict ISP Holdings and ISP from engaging in
certain transactions with members of the Current GAF Group, including making
loans to, or guarantees in favor of, such companies, except pursuant to certain
specified agreements. See 'Description of the New Notes' and 'Risk
Factors--Holding Company Structure and Related Considerations.' For a
description of certain tax sharing agreements, see 'Tax Sharing Agreement.'
 
                                       57

<PAGE>
                              THE EXCHANGE OFFERS
 
PURPOSE AND EFFECT
 
     Each of the Old 9% Notes and the Old 9 3/4% Notes were issued by ISP
Holdings on October 18, 1996. In connection therewith, ISP Holdings entered into
each of the 9% Note Indenture and the 9 3/4% Note Indenture, each of which
requires that ISP Holdings file a registration statement under the Securities
Act with respect to the New Notes and, upon the effectiveness of such
registration statement, offer to the holders of the Old Notes the opportunity to
exchange their Old Notes for a like principal amount of New Notes, which will be
issued without a restrictive legend and, except as set forth below, may be
reoffered and resold by the holder without registration under the Securities
Act. Upon the completion of the Exchange Offers, ISP Holdings' obligations with
respect to the registration of the Old Notes and the New Notes will terminate,
except as provided below. A copy of each Indenture and the Registration
Agreements delivered in connection therewith have been filed as exhibits
Prospectus is a part. As a result of the filing and the effectiveness of the
Registration Statement, certain prospective increases in the interest rate on
the Old Notes provided for in the Registration Agreements will not occur.
Following the completion of the Exchange Offers, holders of Old Notes not
tendered will not have any further registration rights, except as provided
below, and the Old Notes will continue to be subject to certain restrictions on
transfer. Accordingly, the liquidity of the market for the Old Notes could be
adversely affected upon completion of the Exchange Offers.
 
     Based on an interpretation by the staff of the Commission set forth in
no-action letters issued to third parties, ISP Holdings believes that New Notes
issued pursuant to the Exchange Offers in exchange for Old Notes may be offered
for resale, resold and otherwise transferred by a holder thereof (other than any
such holder that is an 'affiliate' of ISP holdings within the meaning of Rule
405 under the Securities Act) without compliance with the registration and
prospectus delivery provisions of the Securities Act, provided that such holder
represents to ISP Holdings that (i) such New Notes are acquired in the ordinary
course of business of such holder, (ii) such holder is not engaging in and does
not intend to engage in a distribution of such new Notes and (iii) such holder
has no arrangement or understanding with any person to participate in the
distribution of such New Notes. Any holder who tenders in the Exchange Offers
for the purpose of participating in a distribution of the New Notes cannot rely
on such interpretation by the staff of the Commission and must comply with the
registration and prospectus delivery requirements of the Securities Act in
connection with a secondary resale transaction. Each broker-dealer that receives
New Notes for its own account in exchange for Old Notes, where such old Notes
were acquired by such broker-dealer as a result of market-making activities or
other trading activities, must acknowledge that it will deliver a prospectus
meeting the requirements of the Securities Act in connection with any resales of
such New Notes. See 'Plan of Distribution.'
 
     In the event that any holder of Old Notes would not receive freely
tradeable New Notes in the Exchange Offers or is not eligible to participate in
the Exchange Offers, such holder can elect, by so indicating on the Letter of
Transmittal and providing certain additional necessary information, to have such
holder's Old Notes registered in a 'shelf' registration statement on an

appropriate form pursuant to Rule 415 under the Securities Act. In the event
that ISP Holdings is obligated to file a 'shelf' registration statement, it will
be required to keep such 'shelf' registration statement effective for a period
of three years or such shorter period that will terminate when all of the Old
Notes covered by such registration statement have been sold pursuant thereto.
Other than as set forth in this paragraph, no holder will have the right to
require ISP Holdings to register such holder's Notes under the Securities Act.
See 'Procedures for Tendering.'
 
CONSEQUENCES OF FAILURE TO EXCHANGE
 
     Following the completion of the Exchange Offers holders of Old Notes not
tendered will not have any further registration rights, except as set forth
above, and the Old Notes will continue to be subject to certain restrictions on
transfer. Accordingly, the liquidity of the market for a holder's Old Notes
could be adversely affected upon completion of the Exchange Offers if such
holder does not participate in the Exchange Offers.
 
                                       58
<PAGE>
TERMS OF THE EXCHANGE OFFERS
 
     Upon the terms and subject to the conditions set forth in this Prospectus
and in the Letter of Transmittal, ISP Holdings will accept any and all Old Notes
validly tendered and not withdrawn prior to 12:00 midnight, New York City time,
on the Expiration Date. ISP Holdings will issue (i) $1,000 principal amount of
New 9% Notes in exchange for each $1,000 principal amount of outstanding Old 9%
Notes accepted in the Exchange Offer relating thereto and (ii) $1,000 principal
amount of New 9 3/4% Notes in exchange for each $1,000 principal amount of
outstanding Old 9 3/4% Notes accepted in the Exchange Offer relating thereto.
Holders may tender some or all of their Old Notes pursuant to the Exchange
Offers. However, Old Notes may be tendered only in integral multiples of $1,000
in principal amount.
 
     The form and terms of New 9% Notes are the same as the form and terms of
the Old 9% Notes and the form and terms of the New 9 3/4 Notes are the same as
the form and terms of the Old 9 3/4% Notes, except, in each case, that the New
Notes have been registered under the Securities Act and hence will not bear
legends restricting the transfer thereof. The New 9% Notes will evidence the
same debt as the Old 9% Notes and will be issued pursuant to, and entitled to
the benefits of, the 9% Indenture pursuant to which the Old Notes were issued
and will be deemed one issue of notes, together with the Old 9% Notes. The New
9 3/4% Notes will evidence the same debt as the Old 9 3/4% Notes and will be
issued pursuant to, and entitled to the benefits of, the 9 3/4% Indenture
pursuant to which the Old Notes were issued and will be deemed one issue of
notes, together with the Old 9 3/4% Notes.
 
     As of the date of this Prospectus, $325,000,000 aggregate principal amount
of the Old 9% Notes and $199,871,000 aggregate principal amount of the Old
9 3/4% Notes were outstanding. This Prospectus, together with the applicable
Letter of Transmittal, is being sent to all registered holders and to others
believed to have beneficial interests in the Old Notes. Holders of Old Notes do
not have any appraisal or dissenters' rights in connection with the Exchange
Offers under the General Corporation Law of the State of Delaware or the

Indentures. ISP Holdings intends to conduct the Exchange Offers in accordance
with the applicable requirements of the Securities Exchange Act of 1934, as
amended (the 'Exchange Act'), and the rules and regulations of the Commission
promulgated thereunder.
 
     ISP Holdings shall be deemed to have accepted validly tendered Old Notes
when, as, and if ISP Holdings has given oral or written notice thereof to the
Exchange Agent. The Exchange Agent will act as agent for the tendering holders
for the purpose of receiving the New Notes from ISP Holdings. If any tendered
Old Notes are not accepted for exchange because of an invalid tender, the
occurrence of certain other events set forth herein or otherwise, certificates
for any such unaccepted Old Notes will be returned, without expense, to the
tendering holder thereof as promptly as practicable after the Expiration Date.
 
     Holders who tender Old Notes in the Exchange Offers will not be required to
pay brokerage commissions or fees or, except as set forth below under 'Transfer
Taxes,' transfer taxes with respect to the exchange of Old Notes pursuant to the
Exchange Offers. ISP Holdings will pay all charges and expenses, other than
certain applicable taxes, in connection with the Exchange Offers. See '--Fees
and Expenses' below.
 
EXPIRATION DATE; AMENDMENTS
 
     The term 'Expiration Date' shall mean 12:00 midnight, New York City time,
on              , 1997, unless ISP Holdings, in its sole discretion, extends
either Exchange Offer (in which case the term 'Expiration Date' shall mean the
later date and time to which such Exchange Offer is extended). ISP Holdings does
not intend to extend either Exchange Offer although it reserves the right to do
so by giving oral or written notice of such extension to the Exchange Agent and
by giving each registered holder notice by means of a press release or other
public announcement of any extension, in each case, prior to 9:00 A.M., New York
City time, on the next business day after the scheduled Expiration Date. ISP
Holdings also reserves the right, in its sole discretion, (i) to delay accepting
any Old Notes or, if any of the conditions set forth below under 'Conditions'
shall not have been satisfied or waived, to terminate either Exchange Offer or
(ii) to amend the terms of either Exchange Offer in any manner, by giving oral
or written notice of such delay, or termination to the Exchange Agent, and by
complying with Rule 14e-1(d) promulgated under the Exchange Act to the extent
such Rule applies. ISP Holdings acknowledges and undertakes to comply with the
provisions of Rule 14e-1(c) promulgated under the Exchange Act, which requires
ISP Holdings to pay the consideration offered, or return the Old Notes
surrendered for exchange, promptly after the termination or withdrawal of the
applicable Exchange Offer. Any such
 
                                       59
<PAGE>
extension, termination or amendment will be followed as promptly as practicable
by a notice to holders of Old Notes of the appropriate issue.
 
PROCEDURES FOR TENDERING
 
     Only a registered holder of Old 9% Notes may tender such Old Notes in the
Exchange Offer relating thereto and only a registered holder of Old 9 3/4% Notes
may tender such Old Notes in the Exchange Offer relating thereto. To tender in

either Exchange Offer, a registered holder must complete, sign, and date the
applicable Letter of Transmittal, or a facsimile thereof, have the signatures
thereon guaranteed if required by the Letter of Transmittal, and mail or
otherwise deliver such Letter of Transmittal or such facsimile to the Exchange
Agent prior to the Expiration Date. In addition, either (i) certificates for
such Old Notes must be received by the Exchange Agent along with the Letter of
Transmittal, or (ii) a timely confirmation of a book-entry transfer (a
'Book-Entry Confirmation') of such Old Notes, if such procedure is available,
into the Exchange Agent's account at The Depository Trust Company (the
'Book-Entry Transfer Facility') pursuant to the procedure for book-entry
transfer described below, must be received by the Exchange Agent prior to the
Expiration Date, or (iii) the registered holder must comply with the guaranteed
delivery procedures described below. To be tendered effectively, the Letter of
Transmittal and other required documents must be received by the Exchange Agent
at the address set forth below under 'Exchange Agent' prior to the Expiration
Date.
 
     The tender by a registered holder which is not withdrawn prior to the
Expiration Date will constitute an agreement between such holder and ISP
Holdings in accordance with the terms and subject to the conditions set forth
herein and in the Letter of Transmittal.
 
     THE METHOD OF DELIVERY OF OLD NOTES AND THE LETTER OF TRANSMITTAL AND ALL
OTHER REQUIRED DOCUMENTS TO THE EXCHANGE AGENT IS AT THE ELECTION AND RISK OF
THE HOLDER. INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE. IN ALL CASES, SUFFICIENT TIME SHOULD BE
ALLOWED TO ASSURE DELIVERY TO THE EXCHANGE AGENT BEFORE THE EXPIRATION DATE. NO
LETTER OF TRANSMITTAL OR OLD NOTES SHOULD BE SENT TO ISP HOLDINGS. HOLDERS MAY
REQUEST THEIR RESPECTIVE BROKERS, DEALERS, COMMERCIAL BANKS, TRUST COMPANIES, OR
NOMINEES TO EFFECT THE ABOVE TRANSACTIONS FOR SUCH HOLDERS.
 
     Any beneficial owner whose Old Notes are registered in the name of a
broker, dealer, commercial bank, trust company, or other nominee and who wishes
to tender should contact the registered holder promptly and instruct such
registered holder to tender on such beneficial owner's behalf. If such
beneficial owner wishes to tender on such owner's own behalf, such owner must,
prior to completing and executing the Letter of Transmittal and delivering such
owner's Old Notes, either make appropriate arrangements to register ownership of
the Old Notes in such beneficial owner's name or obtain a properly completed
bond power from the registered holder. The transfer of registered ownership may
take considerable time.
 
     Signatures on a Letter of Transmittal or a notice of withdrawal, as the
case may be, must be guaranteed by an Eligible Institution (as defined below)
unless (A) Old Notes tendered pursuant thereto are tendered (i) by a registered
holder who has not completed the box entitled 'Special Registration
Instructions' or 'Special Delivery Instructions' on the Letter of Transmittal or
(ii) for the account of an Eligible Institution and (B) the box entitled
'Special Registration Instructions' on the Letter of Transmittal has not been
completed. In the event that signatures on a Letter of Transmittal or a notice
of withdrawal, as the case may be, are required to be guaranteed, such guarantee
must be by a financial institution (including most banks, savings and loan
associations and brokerage houses) that is a participant in the Securities
Transfer Agents Medallion Program, the New York Stock Exchange Medallion Program

or the Stock Exchanges Medallion Program (each an 'Eligible Institution').
 
     If the Letter of Transmittal is signed by a person other than the
registered holder of any Old Notes listed therein, such Old Notes must be
endorsed or accompanied by a properly completed bond power and signed by such
registered holder as such registered holder's name appears on such Old Notes.
 
     If the Letter of Transmittal or any Old Notes or bond powers are signed by
trustees, executors, administrators, guardians, attorneys-in-fact, officer of
corporations, or others acting in a fiduciary or
 
                                       60
<PAGE>
representative capacity, such persons should so indicate when signing, and
unless waived by ISP Holdings, evidence satisfactory to ISP Holdings of their
authority to so act must be submitted with the Letter of Transmittal.
 
     All questions as to the validity, form, eligibility (including time of
receipt), acceptance, and withdrawal of tendered Old Notes will be determined by
ISP Holdings in its sole discretion, which determination will be final and
binding. ISP Holdings reserves the absolute right to reject any and all Old
Notes not properly tendered or any Old Notes ISP Holdings' acceptance of which
would, in the opinion of counsel for ISP Holdings, be unlawful. ISP Holdings
also reserves the right to waive any defects, irregularities, or conditions of
tender as to particular Old Notes. ISP Holdings' interpretation of the terms and
conditions of the Exchange Offers (including the instructions in the Letter of
Transmittal) will be final and binding on all parties. Unless waived, defects or
irregularities in connection with tenders of Old Notes must be cured within such
time as ISP Holdings shall determine. Although ISP Holdings intends to notify
holders of defects or irregularities with respect to tenders of Old Notes,
neither ISP Holdings, the Exchange Agent, nor any other person shall incur any
liability for failure to give such notification. Tenders of Old Notes will not
be deemed to have been made until such defects or irregularities have been cured
or waived. Any Old Notes received by the Exchange Agent that are not properly
tendered and as to which the defects or irregularities have not been cured or
waived will be returned by the Exchange Agent to the tendering holders, unless
otherwise provided in the Letter of Transmittal, as soon as practicable
following the Expiration Date.
 
     In addition, ISP Holdings reserves the right in its sole discretion to
purchase or make offers for, or to offer New Notes for, any Old Notes that
remain outstanding subsequent to the Expiration Date or, as set forth below
under 'Conditions,' to terminate either Exchange Offer and, to the extent
permitted by applicable law, purchase Old Notes in the open market, in privately
negotiated transactions or otherwise. The terms of any such purchases or offers
could differ from the terms of the Exchange Offers.
 
     By tendering, each holder will represent to ISP Holdings that, among other
things, (i) the New Notes acquired pursuant to the Exchange Offer are being
acquired in the ordinary course of business of such holder, (ii) the holder is
not engaging in and does not intend to engage in a distribution of such New
Notes, (iii) the holder does not have an arrangement or understanding with any
person to participate in the distribution of such New Notes and (iv) the holder
is not an 'affiliate,' as defined under Rule 405 of the Securities Act, of ISP

Holdings.
 
     In all cases, issuance of New Notes for Old Notes that are accepted for
exchange pursuant to either Exchange Offer will be made only after timely
receipt by the Exchange Agent of certificates for such Old Notes or a timely
Book-Entry Confirmation of such Old Notes into the Exchange Agent's account at
the Book-Entry Transfer Facility, a properly completed and duly executed Letter
of Transmittal and all other required documents. If any tendered Old Notes are
not accepted for any reason set forth in the terms and conditions of the
Exchange Offers or if Old Notes are submitted for a greater principal amount
than the holder desires to exchange, such unaccepted or non-exchanged Old Notes
(or Old Notes in substitution therefor) will be returned without expense to the
tendering holder thereof (or, in the case of Old Notes tendered by book-entry
transfer into the Exchange Agent's account at the Book-Entry Transfer Facility
pursuant to the book-entry transfer procedures described below, such
non-exchanged Old Notes will be credited to such tendering holder's account
maintained with such Book-Entry Transfer Facility) as promptly as practicable
after the expiration or termination of the Exchange Offer.
 
BOOK-ENTRY TRANSFER
 
     The Exchange Agent will make a request to establish an account with respect
to the Old Notes at the Book-Entry Transfer Facility for purposes of the
Exchange Offers within two business days after receipt of this Prospectus, and
any financial institution that is a participant in the Book-Entry Transfer
Facility's system may make book-entry delivery of Old Notes by causing the
Book-Entry Transfer Facility to transfer such Old Notes into the Exchange
Agent's account at the Book-Entry Transfer Facility in accordance with such
Book-Entry Transfer Facility's procedures for transfer. However, although
delivery of Old Notes may be effected through book-entry transfer at the
Book-Entry Transfer Facility, the Letter of Transmittal or facsimile thereof,
with any required signature guarantees and any other required documents, must,
in any case, be transmitted to and received by the Exchange Agent at the address
set forth below under 'Exchange Agent' on or prior to the Expiration Date or the
guaranteed delivery procedures described below must be complied with.
 
                                       61
<PAGE>
GUARANTEED DELIVERY PROCEDURES
 
     If a registered holder of the Old 9% Notes or Old 9 3/4% Notes desires to
tender such Old Notes and such Old Notes are not immediately available, or time
will not permit such holder's Old Notes or other required documents to reach the
Exchange Agent before the Expiration Date, or the procedure for book-entry
transfer cannot be completed on a timely basis, a tender may be effected if (i)
the tender is made through an Eligible Institution, (ii) on or prior to 12:00
midnight, New York City time, on the Expiration Date, the Exchange Agent
receives from such Eligible Institution a properly completed and duly executed
Letter of Transmittal (or a facsimile thereof) and Notice of Guaranteed
Delivery, substantially in the form provided by ISP Holdings (by facsimile
transmission, mail or hand delivery), setting forth the name and address of the
holder of Old Notes and the amount of Old Notes tendered, stating that the
tender is being made thereby and guaranteeing that within three New York Stock
Exchange ('NYSE') trading days after the date of execution of the Notice of

Guaranteed Delivery, the certificates for all physically tendered Old Notes, in
proper form for transfer, or a Book-Entry Confirmation, as the case may be, and
any other documents required by the Letter of Transmittal will be deposited by
the Eligible Institution with the Exchange Agent, and (iii) the certificates for
all physically tendered Old Notes, in proper form for transfer, or a Book-Entry
Confirmation, as the case may be, and all other documents required by the Letter
of Transmittal, are received by the Exchange Agent within three NYSE trading
days after the date of execution of the Notice of Guaranteed Delivery.
 
WITHDRAWAL RIGHTS
 
     Tenders of Old 9% Notes or Old 9 3/4% Notes may be withdrawn at any time
prior to 12:00 midnight, New York City time, on the Expiration Date.
 
     For a withdrawal of a tender of Old Notes to be effective, a written or
facsimile transmission notice of withdrawal must be received by the Exchange
Agent at its address set forth below under 'Exchange Agent' prior to 12:00
midnight, New York City time, on the Expiration Date. Any such notice of
withdrawal must (i) specify the name of the person having deposited the Old
Notes to be withdrawn (the 'Depositor'), (ii) identify the Old Notes to be
withdrawn (including the certificate number or numbers and principal amount of
such Old Notes), (iii) be signed by the holder in the same manner as the
original signature on the Letter of Transmittal by which such Old Notes were
tendered (including any required signature guarantees) or be accompanied by
documents of transfer sufficient to have the Trustee register the transfer of
such Old Notes into the name of the person withdrawing the tender, and (iv)
specify the name in which any such Old Notes are to be registered, if different
from that of the Depositor. All questions as to the validity, form, and
eligibility (including time of receipt) of such notices will be determined by
ISP Holdings, whose determination shall be final and bindings on all parties.
Any Old Notes so withdrawn will be deemed not to have been validly tendered for
exchange for purposes of the Exchange Offers. Any Old Notes which have been
tendered for exchange but which are not exchanged for any reason will be
returned to the holder thereof without cost to such holder as soon as
practicable after withdrawal, rejection of tender, or termination of the
applicable Exchange Offer. Properly withdrawn Old Notes may be retendered by
following one of the procedures described under 'Procedures for Tendering' above
at any time on prior to 12:00 midnight, New York City time, on the Expiration
Date.
 
CONDITIONS
 
     The consummation of either Exchange Offer is not conditioned on the
consummation of the other Exchange Offer. Notwithstanding any other provisions
of the Exchange Offers and, however, subject to its obligations pursuant to the
Registration Agreements, ISP Holdings shall not be required to accept for
exchange, or to issue New Notes in exchange for, any Old Notes and may terminate
or amend either Exchange Offer, if at any time before the acceptance of such New
Notes for exchange, any of the following events shall occur:
 
          A.  any injunction, order or decree shall have been issued by any
     court or any governmental agency that would prohibit, prevent or otherwise
     materially impair the ability of ISP Holdings to proceed with such Exchange
     Offer; or

 
          B.  such Exchange Offer shall violate any applicable law or any
     applicable interpretation of the staff of the Commission.
 
                                       62
<PAGE>
     The foregoing conditions are for the sole benefit of ISP Holdings and may
be asserted by ISP Holdings regardless of the circumstances giving rise to any
such condition or may be waived by ISP Holdings in whole or in part at any time
and from time to time in its sole discretion. The failure by ISP Holdings at any
time to exercise any of the foregoing rights shall not be deemed a waiver of any
such right and such right shall be deemed an ongoing right which may be asserted
at any time and time to time.
 
     In addition, ISP Holdings will not accept for exchange any Old Notes
tendered, and no New Notes will be issued in exchange for any such Old Notes, if
at such time any stop order shall be threatened by the Commission or be in
effect with respect to the Registration Statement of which this Prospectus is a
part or the qualification of the Indenture under the Trust Indenture Act of
1939, as amended.
 
     Neither Exchange Offer is conditioned on any minimum principal amount of
Old Notes being tendered for exchange.
 
ASSISTANCE
 
     All executed Letters of Transmittal should be directed to the Exchange
Agent. Questions and requests for assistance may be directed to the Exchange
Agent as provided below under 'Exchange Agent.'
 
EXCHANGE AGENT
 
     The Bank of New York has been appointed as Exchange Agent for the Exchange
Offers. Questions, requests for assistance and requests for additional copies of
the Prospectus, the Letter of Transmittal and other related documents should be
directed to the Exchange Agent addressed as follows:
 
                    By Registered or Certified Mail, By Hand
                            or by Overnight Courier:
 
                              The Bank of New York
                             101 Barclay Street--7E
                            New York, New York 10286
                          Attn: Reorganization Section
 
By Facsimile:                                                      By Telephone:
(212) 571-3080                                                    (212) 815-6333
 
     The Exchange Agent also acts as trustee under the Indentures.
 
FEES AND EXPENSES
 
     ISP Holdings will not make any payments to brokers, dealers, or others
soliciting acceptances of the Exchange Offer. The principal solicitation is

being made by mail; however, additional solicitations may be made in person or
by telephone by officers and employees of ISP Holdings.
 
     The estimated cash expenses to be incurred in connection with the Exchange
Offers will be paid by ISP Holdings and are estimated in the aggregate to be
approximately $250,000 which includes fees and expenses of the Exchange Agent,
accounting, legal, printing and related fees and expenses.
 
TRANSFER TAXES
 
     Holders who tender their Old Notes for exchange will not be obligated to
pay any transfer taxes in connection therewith, except that holders who instruct
ISP Holdings to register New Notes in the name of, or request that Old Notes not
tendered or not accepted in the Exchange Offers be returned to, a person other
than the registered tendering holder will be responsible for the payment of any
applicable transfer tax thereon.
 
ACCOUNTING TREATMENT
 
     ISP Holdings will not recognize any gain or loss for accounting purposes
upon the consummation of the Exchange Offers. The expense of the Exchange Offers
will be amortized by ISP Holdings over the respective terms of the New Notes
under generally accepted accounting principles.
 
                                       63

<PAGE>
                          DESCRIPTION OF THE NEW NOTES
 
GENERAL
 
     The Old 9% Notes were issued under an Indenture dated as of October 18,
1996 (the '9% Note Indenture') between ISP Holdings and the Bank of New York, as
trustee (the 'Trustee'). The Old 9 3/4% Notes were issued under an Indenture
dated as of October 18, 1996 (the '9 3/4% Note Indenture') between ISP Holdings
and the Trustee. A copy of each of the 9% Note Indenture and the 9 3/4% Note
Indenture (each individually, an 'Indenture' and together, the 'Indentures') has
been filed as an exhibit to the Registration Statement of which this Prospectus
is a part. As a result of the consummation of the Spin Off Transactions, G-I
Holdings and its subsidiaries, including BMCA, are no longer subsidiaries of ISP
Holdings. Therefore, restrictions set forth in the Indentures with respect to
the operations of G-I Holdings and its subsidiaries, including BMCA, are no
longer applicable. The New 9% Notes will be issued under the 9% Note Indenture
and the New 9 3/4% Notes will be issued under the 9 3/4% Note Indenture, each of
which will be qualified under the Trust Indenture Act of 1939, as amended (the
'TIA'), upon the effectiveness of the Registration Statement of which this
Prospectus is a part. The form and terms of each issue of New Notes and the
respective series of Old Notes are the same except that the New Notes have been
registered under the Securities Act and, therefore, will not bear legends
restricting the transfer thereof. The following summary of certain provisions of
the Indentures does not purport to be complete and is subject to, and is
qualified in its entirety by reference to, the TIA, and to all of the provisions
of each Indenture including the definitions of certain terms therein and those
terms made a part of such Indenture by reference to the TIA as in effect on the
date of such Indenture. The definitions of certain capitalized terms used in the
following summary are set forth under 'Certain Definitions.' The term '9% Notes'
means the New 9% Notes and the Old 9% Notes treated as a single class. The term
'9 3/4% Notes' means the New 9 3/4% Notes and the Old 9 3/4% Notes treated as a
single class. The term 'Notes' means the 9% Notes and the 9 3/4% Notes,
collectively. For purposes of this section, the 'Company' means ISP Holdings
Inc., not including any of its Subsidiaries.
 
     The 9% Notes will be general unsecured obligations of the Company and will
rank senior to all subordinated indebtedness of the Company and pari passu in
right of payment to the 9 3/4% Notes and to all other unsubordinated
indebtedness of the Company. The 9 3/4% Notes will be general unsecured
obligations of the Company and will rank senior to all subordinated indebtedness
of the Company and pari passu in right of payment to the 9% Notes and to all
other unsubordinated indebtedness of the Company. The Notes will be effectively
subordinated to all secured indebtedness of the Company to the extent of the
assets securing such indebtedness and to all indebtedness and other obligations
of the Company's subsidiaries. See Note 8 to Consolidated Financial Statements.
 
PRINCIPAL, MATURITY AND INTEREST
 
     The 9% Notes are limited in aggregate principal amount to $325,000,000 and
will mature on October 15, 2003. The 9% Notes bear interest at a rate of 9% per
annum from the Issue Date. Interest is payable semiannually on each April 15 and
October 15 (each, a '9% Interest Payment Date'), commencing on April 15, 1997,
to the persons who are registered Holders on the immediately preceding April 1

and October 1, whether or not a business day (each, a '9% Interest Record
Date'). Accrued and unpaid interest on the Old 9% Notes will be paid in cash on
the first 9% Interest Payment Date to the persons who are registered Holders of
9% Notes on the 9% Interest Record Date for such 9% Interest Payment Date.
 
     The 9 3/4% Notes are limited in aggregate principal amount to $199,871,000
and will mature on February 15, 2002. The 9 3/4% Notes bear interest at a rate
of 9 3/4% per annum from the Issue Date. Interest will be payable semiannually
on each February 15 and August 15 (each, a '9 3/4% Interest Payment Date'),
commencing on February 15, 1997, to the persons who are registered Holders on
the immediately preceding February 1 and August 1, whether or not a business day
(each, a '9 3/4% Interest Record Date'). Accrued and unpaid interest on the Old
9 3/4% Notes will be paid in cash on the first 9 3/4% Interest Payment Date to
the persons who are registered Holders of 9 3/4% Notes on the 9 3/4% Interest
Record Date for such 9 3/4% Interest Payment Date.
 
     If the Company defaults in a payment of interest on the Notes, it shall pay
the default interest, plus, to the extent permitted by law, any interest payable
on the defaulted interest, to the Persons who are Holders on a
 
                                       64
<PAGE>
subsequent special record date. Such special record date shall be the fifteenth
day next preceding the date fixed by the Company for the payment of defaulted
interest, whether or not such day is a business day. At least 15 days before the
special record date, the Company shall mail or cause to be mailed to each Holder
and the Trustee a notice that states the special record date, the payment date
and the amount of defaulted interest to be paid.
 
     Interest on the Notes will be computed on the basis of a 360-day year of
twelve 30-day months.
 
     The Notes will not be entitled to the benefit of any mandatory sinking
fund.
 
OPTIONAL REDEMPTION
 
     The 9% Notes are redeemable, at the Company's option, in whole at any time
or in part from time to time, on and after October 15, 1999, upon not less than
30 nor more than 60 days' notice, at the following redemption prices (expressed
as percentages of the principal amount thereof) if redeemed during the
twelve-month period commencing on October 15 of the year set forth below, plus,
in each case, accrued and unpaid interest thereon, if any, to the date of
redemption:
 
<TABLE>
<CAPTION>
YEAR                                                                       PERCENTAGE
- ------------------------------------------------------------------------   ----------
<S>                                                                        <C>
1999....................................................................      104.5%
2000....................................................................      103.0%
2001....................................................................      101.5%
2002....................................................................      100.0%

</TABLE>
 
     In the event that on or prior to October 15, 1999, (x) the Company
consummates a sale of its Common Stock or (y) ISP or the Company consummates a
sale of the Common Stock of ISP, the Company may, at its option, redeem, but
only to the extent of net cash proceeds therefrom actually received by the
Company, up to 50% of the principal amount of the 9% Notes then outstanding at a
redemption price equal to 109% of the principal amount thereof plus accrued
interest thereon to the date of redemption; provided, however, that, no such
redemption may be made if and to the extent that, after giving effect thereto,
less than 50% of the principal amount of 9% Notes originally issued would be
outstanding. Any such redemption shall be made within 75 days of the first
consummation of any such sale.
 
     The Company also has the right to redeem all, but not less than all, of the
9% Notes upon a Change of Control. See 'Change of Control Put and Call.'
 
     The 9 3/4% Notes are redeemable, at the Company's option, in whole at any
time or in part from time to time, on and after October 15, 1999, upon not less
than 30 nor more than 60 days' notice, at the following redemption prices
(expressed as percentages of the principal amount thereof) if redeemed during
the twelve-month period commencing on October 15 of the year set forth below,
plus, in each case, accrued and unpaid interest thereon, if any, to the date of
redemption:
 
<TABLE>
<CAPTION>
YEAR                                                                       PERCENTAGE
- ------------------------------------------------------------------------   ----------
<S>                                                                        <C>
1999....................................................................    104.8750%
2000....................................................................    102.4375%
2001....................................................................    100.0000%
</TABLE>
 
     In the event that on or prior to October 15, 1999, (x) the Company
consummates a sale of its Common Stock or (y) ISP or the Company consummates a
sale of the Common Stock of ISP, the Company may, at its option, redeem, but
only to the extent of net cash proceeds therefrom actually received by the
Company, up to 50% of the principal amount of the 9 3/4% Notes then outstanding
at a redemption price equal to 109.75% of the principal amount thereof plus
accrued interest thereon to the date of redemption; provided, however, that, no
such redemption may be made if and to the extent that, after giving effect
thereto, less than a majority of the principal amount of 9 3/4% Notes originally
issued would be outstanding. Any such redemption shall be made within 75 days of
the first consummation of any such sale.
 
     The Company also has the right to redeem all, but not less than all, of the
9 3/4% Notes upon a Change of Control. See 'Change of Control Put and Call.'
 
                                       65
<PAGE>
SELECTION AND NOTICE OF REDEMPTION
 

     In the event that less than all of the Notes of either class are to be
redeemed at any time, selection of such Notes for redemption will be made by the
Trustee in compliance with the requirements of the principal national securities
exchange, if any, on which such Notes are listed or, if such Notes are not then
listed on a national securities exchange, on a pro rata basis, by lot or by such
method as the Trustee shall deem fair and appropriate; provided, however, that
no Notes of a principal amount of $1,000 or less shall be redeemed in part;
provided, further, that if a partial redemption is made in accordance with the
second or fifth paragraph under 'Optional Redemption,' selection of the Notes or
portions thereof for redemption shall be made by the Trustee only on a pro rata
basis with the other Notes of such class or on as nearly a pro rata basis as is
practicable (subject to procedures of the Depository Trust Company), unless such
method is otherwise prohibited. Notice of redemption shall be mailed by
first-class mail at least 30 but not more than 60 days before the redemption
date (or, if applicable, at such other time as is provided below under 'Change
of Control Put and Call') to each Holder of Notes to be redeemed at its
registered address. If any Note is to be redeemed in part only, the notice of
redemption that relates to such Note shall state the portion of the principal
amount thereof to be redeemed. A new Note in a principal amount equal to the
unredeemed portion thereof will be issued in the name of the Holder thereof upon
cancellation of the original Note. On and after the redemption date, interest
will cease to accrue on Notes or portions thereof called for redemption as long
as the Company has deposited with the Paying Agent funds in satisfaction of the
applicable redemption price pursuant to the Indenture.
 
CHANGE OF CONTROL PUT AND CALL
 
     In the event of any Change of Control, each Holder shall have the right, at
such Holder's option, to require the Company to purchase all or any portion (in
integral multiples of $1,000) of such Holder's Notes on the date (the 'Change of
Control Payment Date') which is 25 business days after the date the Change of
Control Notice (as defined below) is mailed or is required to be mailed (or such
later date as is required by applicable law) at 101% of the principal amount
thereof (or, if lower, the applicable redemption prices then in effect under the
provisions described in the first and fourth paragraphs under '--Optional
Redemption') plus accrued interest thereon to the Change of Control Payment
Date.
 
     The Company or, at the request of the Company, the Trustee shall send, by
first-class mail, postage prepaid, to all Holders, within ten business days
after the occurrence of each Change of Control, a notice of the occurrence of
such Change of Control (the 'Change of Control Notice'), specifying a date by
which a Holder must notify the Company of such Holder's intention to exercise
the repurchase right and describing the procedure that such Holder must follow
to exercise such right. The Company is required to deliver a copy of such notice
to the Trustee.
 
     Each Change of Control Notice shall state: (1) that the change of control
offer is being made pursuant to this covenant and that all Notes of such class
tendered will be accepted for payment; (2) the purchase price and the Change of
Control Payment Date; (3) that any Note not tendered will continue to accrue
interest; (4) that, unless the Company defaults in making payment therefor, any
Note accepted for payment pursuant to the change of control offer shall cease to
accrue interest after the Change of Control Payment Date; (5) that Holders

electing to have a Note purchased pursuant to a change of control offer will be
required to surrender the Note in accordance with the instructions set forth
therein; (6) that the Company has the right, pursuant to provisions described in
the next paragraph, to redeem any Notes not tendered at the Call Price (defined
below); and (7) the circumstances and relevant facts regarding such Change of
Control.
 
     In the event a Change of Control occurs, the Company may redeem all, but
not less than all, of the Notes of each class then outstanding, at a redemption
price equal to 100% of the principal amount thereof plus accrued interest to the
redemption date, plus the Applicable Premium (the 'Call Price'). Notice of any
redemption to be made pursuant to this paragraph as a result of the occurrence
of a Change of Control must be given no later than 10 days after the Change of
Control Payment Date applicable to the Change of Control giving rise to such
redemption, and redemption must be made within 30 days of the date of the
notice.
 
     The Company shall comply with all applicable Federal and state securities
laws in connection with each Change of Control Notice.
 
                                       66
<PAGE>
CERTAIN DEFINITIONS
 
     'Acquired Debt,' with respect to any Person, means (i) Debt (including any
then unutilized commitment under any revolving working capital facility) of an
entity, which entity is acquired by such Person or any of its Subsidiaries after
the Issue Date; provided that such Debt (including any such facility) is
outstanding at the time of the acquisition of such entity, is not created in
contemplation of such acquisition and is not, directly or indirectly, recourse
(including by way of set-off) to such Person or its Subsidiaries or any of their
respective assets other than to the entity and its Subsidiaries so acquired and
the assets of the entity and its Subsidiaries so acquired, (ii) Debt of such
Person that is not, directly or indirectly, recourse (including by way of
set-off) to such Person and its Subsidiaries or any of their respective assets
other than to specified assets acquired by such Person or its Subsidiaries after
the Issue Date, which Debt is outstanding at the time of the acquisition of such
assets and is not created in contemplation of such acquisition, or (iii)
Refinancings of Debt described in clauses (i) or (ii), provided that the
recourse with respect to such Refinancing Debt is limited to the same extent as
the Debt so Refinanced.
 
     'Additional Interest' means all additional interest owing under the
Registration Rights Agreements.
 
     'Affiliate' of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
'control' when used with respect to any Person means the power to direct the
management and policies of such Person, directly or indirectly, whether through
the ownership of voting securities, by contract or otherwise; and the terms
'controlling' and 'controlled' having meanings correlative to the foregoing. For
the avoidance of doubt, GAF and its Affiliates (so long as they are under common
control with the Company) shall be deemed to be Affiliates of the Company.

 
     'Applicable Premium' means, with respect to any Note, the greater of (x)
1.0% of the principal amount of such Note and (y) the excess, if any, of (a) the
present value of the required remaining interest payments, principal and future
optional redemption premium (if applicable) of such Note, discounted on a
semi-annual bond equivalent basis from either the maturity date of the Note or
the optional redemption date to the applicable redemption date at a per annum
interest rate equal to the Treasury Yield for such redemption date plus 100
basis points, over (b) the sum of the principal amount of such Note plus accrued
and unpaid interest to the redemption date.
 
     'Asset Sale' means, with respect to any Person, the sale, lease, assignment
or other disposition (including, without limitation, dispositions pursuant to
any consolidation, merger or sale and leaseback transaction) by such Person or
any of its Subsidiaries in any single transaction or series of related
transactions of (x) any Capital Stock of any Subsidiary of such Person or (y)
all or substantially all of the properties and assets of any division or line of
business of such Person or any of its Recourse Subsidiaries, in either case,
other than by the Company or any of its Subsidiaries to the Company or any of
its Subsidiaries. For the purposes of this definition, the term 'Asset Sale'
shall not include (A) any sale, lease, assignment or other disposition of
properties or assets that is governed by the provisions described under
'--Merger, Etc.,' (B) any sale, lease, assignment or other disposition by a
Person that has outstanding Long-Term Debt all of which (x) are rated BBB- or
higher by S&P and are not on credit watch by S&P for a possible downgrade below
BBB- or (y) are rated Baa3 or higher by Moody's and are not on credit watch by
Moody's for a possible downgrade below Baa3, or (C) any sale of Common Stock the
proceeds of which are used pursuant to the provisions described in the second or
fifth paragraph under '-- Optional Redemption.'
 
     'Average Life' means, with respect to any Debt, the quotient obtained by
dividing (i) the sum of the products of (a) the number of years from the date of
the transaction or event giving rise to the need to calculate the Average Life
of such Debt to the date, or dates, of each successive scheduled principal
payment of such Debt multiplied by (b) the amount of each such principal payment
by (ii) the sum of all such principal payments.
 
                                       67

<PAGE>
     'Bankruptcy Law' means Title 11, U.S. Code or any similar Federal, state or
foreign law for the relief of debtors.
 
     'Board of Directors' of any Person means the Board of Directors or similar
governing body of such Person, or any duly authorized committee of such Board of
Directors or similar governing body.
 
     'Board Resolution' means, with respect to the Board of Directors of any
Person, a copy of a resolution certified by the Secretary or Assistant Secretary
of such Person to have been duly adopted by such Board of Directors and to be in
full force and effect on the date of such certification and delivered to the
Trustee.
 
     'BMCA' means Building Materials Corporation of America, a Delaware
corporation, and its successors.
 
     'Capitalized Lease Obligation' means any rental obligation that, in
accordance with GAAP, is required to be classified and accounted for as a
capitalized lease and the amount of Debt represented by such obligation shall be
the capitalized amount of such obligation determined in accordance with GAAP;
and the stated maturity thereof shall be the date of the last payment of rent or
any other amount due in respect of such obligation.
 
     'Capital Stock' of any Person means any and all shares, interests
(including partnership interests), warrants, rights, options or other interests,
participations or other equivalents of or interests in (however designated)
equity of such Person, including Common Stock or Preferred Stock, whether now
outstanding or issued after the Issue Date, but excluding any debt securities
convertible into or exchangeable for such equity.
 
     'Cash Equivalents' means (i) marketable direct obligations Issued by, or
unconditionally Guaranteed by, the United States Government or Issued by any
agency thereof and backed by the full faith and credit of the United States, in
each case maturing within one year from the date of acquisition thereof, (ii)
marketable direct obligations Issued by any state of the United States of
America or any political subdivision of any such state or any public
instrumentality thereof maturing within one year from the date of acquisition
thereof and, at the time of acquisition, having one of the two highest ratings
obtainable from either S&P or Moody's, (iii) commercial paper maturing no more
than one year from the date of creation thereof and, at the time of acquisition,
having a rating of at least A-1 from S&P or at least P-1 from Moody's, (iv)
certificates of deposit or bankers' acceptances maturing no more than one year
from the date of acquisition thereof Issued by any commercial bank organized
under the laws of the United States of America or any state thereof or the
District of Columbia or any U.S. branch of a foreign bank having at the date of
acquisition thereof combined capital surplus of not less than $250,000,000, (v)
repurchase obligations with a term of not more than 30 days for underlying
securities of the types described in clause (i) above entered into with any bank
meeting the qualifications specified in clause (iv) above and (vi) investments
in money market funds having assets in excess of $500,000,000 and which invest
substantially all their assets in securities of the types described in clauses
(i) through (v) above.
 

     'Change of Control' means the occurrence of any of the following events:
 
          (i) prior to the first public offering of Voting Stock of the Company,
     the Permitted Holders cease to be the 'beneficial owner' (as defined in
     Rules 13d-3 and 13d-5 under the Exchange Act), directly or indirectly, of
     majority voting power of the Voting Stock of the Company, whether as a
     result of issuance of securities of the Company, any merger, consolidation,
     liquidation or dissolution of the Company, any direct or indirect transfer
     of securities by any Permitted Holder or otherwise (for purposes of this
     clause (i) and clauses (ii) and (iv) below, the Permitted Holders shall be
     deemed to beneficially own any Voting Stock of a corporation (the
     'specified corporation') held by any other corporation (the 'parent
     corporation') so long as the Permitted Holders beneficially own (as so
     defined), directly or indirectly, a majority of the Voting Stock of the
     parent corporation);
 
          (ii) any 'Person' (as such term is used in sections 13(d) and 14(d) of
     the Exchange Act), other than one or more Permitted Holders, is or becomes
     the beneficial owner (as defined in clause (i) above, except that a Person
     shall be deemed to have 'beneficial ownership' of all shares that any such
     Person has the right to acquire, whether such right is exercisable
     immediately or only after the passage of time), directly or indirectly, of
     more than 35% of the Voting Stock of the Company, but only if the Permitted
     Holders beneficially own (as defined in clause (i) above), directly or
     indirectly, in the aggregate a lesser percentage of the Voting Stock of the
     Company than such other Person and do not have the right or ability by
     voting
 
                                       68
<PAGE>
     power, contract or otherwise to elect or designate for election a majority
     of the Board of Directors of the Company;
 
          (iii) during any period of two consecutive years, individuals who at
     the beginning of such period constituted the Board of Directors of the
     Company or its predecessor (together with any new directors whose election
     by such Board or whose nomination for election by the shareholders of the
     Company or its predecessor was approved by a vote of a majority of the
     directors of the Company then still in office who were either directors at
     the beginning of such period or whose election or nomination for election
     was previously so approved) cease for any reason to constitute a majority
     of the Board of Directors of the Company then in office; or
 
          (iv) either (x) the Permitted Holders or (y) the Company ceases, for
     any reason, to be the beneficial owner (as defined in clause (i) above),
     directly or indirectly, of majority voting power of the Voting Stock of
     ISP, whether as a result of issuance of securities, any merger,
     consolidation, liquidation or dissolution, any direct or indirect transfer
     of securities by any Permitted Holder or otherwise.
 
     'Commission' means the Securities and Exchange Commission, as from time to
time constituted, created under the Exchange Act, or if at any time after the
execution of the Indenture such Commission is not existing and performing the
duties now assigned to it under the TIA, then the body performing such duties at

such time.
 
     'Common Stock' of any Person means any and all shares, interests,
participations, or other equivalents (however designated) of such Person's
common stock whether now outstanding or issued after the Issue Date.
 
     'Consolidated EBITDA Coverage Ratio' means, with respect to any Person, for
any period, the ratio of (i) EBITDA of such Person for such period to (ii)
Consolidated Interest Expense of such Person for such period; provided, however,
that (A) if such Person or any of its Subsidiaries has Issued any Debt or
Capital Stock since the beginning of such period that remains outstanding on the
date such calculation is made or if the transaction giving rise to the need to
calculate the Consolidated EBITDA Coverage Ratio is an Issuance of Debt or
Capital Stock, or both, EBITDA and Consolidated Interest Expense for such period
shall be calculated after giving effect, on a pro forma basis, to the issuance
of such Debt or Capital Stock as if such Debt or Capital Stock had been Issued
on the first day of such period and the discharge of any other Debt or Capital
Stock Refinanced or otherwise discharged with the proceeds of such new Debt or
Capital Stock as if such discharge had occurred on the first day of such period;
(B) if since the beginning of such period such Person or any of its Subsidiaries
shall have made any asset sale out of the ordinary course of business, EBITDA
for such period shall be reduced by an amount equal to the EBITDA (if positive)
directly attributable to the assets which are the subject of such asset sale for
such period, or increased by an amount equal to the EBITDA (if negative),
directly attributable thereto for such period and Consolidated Interest Expense
for such period shall be reduced by an amount equal to the Consolidated Interest
Expense directly attributable to any Debt or Capital Stock of such Person or any
Subsidiary of such Person and the amount of any other Debt or Capital Stock
Refinanced or otherwise discharged with respect to such Person and its
continuing Subsidiaries (including as a result of the assumption of such Debt or
Capital Stock by the purchaser of such assets, provided that such Person or any
of its Subsidiaries is no longer liable therefor) in connection with such asset
sale for such period (or if the Capital Stock of any Subsidiary of such Person
is sold, the Consolidated Interest Expense for such period directly attributable
to the Debt of such Subsidiary to the extent such Person and its continuing
Subsidiaries are no longer liable for such Debt after such sale) (it being
understood that the Spin Off shall be considered an asset sale out of the
ordinary course of business for purposes of this clause (B)); and (C) if since
the beginning of the period such Person or any of its Subsidiaries (by merger or
otherwise) shall have made an Investment in any Subsidiary of such Person (or
any Person which becomes a Subsidiary of such Person) or an acquisition of
assets, including any acquisition of assets occurring in connection with a
transaction causing a calculation to be made hereunder, which constitutes all of
an operating unit of a business, EBITDA and Consolidated Interest Expense for
such period shall be calculated after giving pro forma effect thereto, as if
such Investment or acquisition occurred on the first day of such period. For
purposes of this definition, pro forma calculations shall be determined in good
faith by a responsible financial or accounting officer of the Person with
respect to which the calculation is being made. If any Debt or Capital Stock
bears a floating rate of interest or dividends and is being given pro forma
effect, the interest on such Debt and the dividends on such Capital Stock shall
be calculated as if the rate in effect on the date of determination had been the
applicable rate for the entire period.
 

                                       69
<PAGE>
     'Consolidated Interest Expense' means with respect to any Person, for any
period, the sum of (a) the interest expense of such Person and its consolidated
Subsidiaries (other than interest expense related to Non-Recourse Debt) for such
period as determined in accordance with GAAP consistently applied, plus (b) the
product of (x) the amount of all dividends paid or accrued on any series of
preferred stock of such Person (other than non-Redeemable Stock) and its
Recourse Subsidiaries times (y) a fraction, the numerator of which is one and
the denominator of which is one minus the effective combined consolidated
federal, state and local tax rate of such Person, expressed as a decimal.
 
     'Consolidated Net Income (Loss)' means with respect to any Person, for any
period, the consolidated net income (or loss) of such Person and its
consolidated Subsidiaries for such period as determined in accordance with GAAP,
adjusted to the extent included in calculating such net income (or loss), by
excluding (i) all extraordinary gains in such period net of all extraordinary
losses in such period; (ii) net income (or loss) of any other Person
attributable to any period prior to the date of combination of such other Person
with such Person or any of its Subsidiaries on a 'pooling-of-interests' basis;
(iii) net gains or losses in respect of dispositions of assets by such Person or
any of its Subsidiaries (including pursuant to a sale-and-leaseback arrangement)
other than in the ordinary course of business; (iv) the net income (loss) of any
Subsidiary of such Person (other than, in calculating the consolidated net
income (loss) of the Company, the consolidated net income (loss) of ISP) to the
extent that the declaration of dividends or distributions by that Subsidiary of
that income is not at the time permitted, directly or indirectly, by operation
of the terms of its charter or any agreement, instrument, judgment, decree,
order, statute, rule or governmental regulations applicable to that Subsidiary
or its shareholders; (v) the net income (or net loss) of any other Person that
is not a Subsidiary of the first Person with respect to which Consolidated Net
Income is being calculated (the 'first Person') and in which any other Person
(other than such first Person and or any of its Subsidiaries) has an equity
interest or of a Non-Recourse Subsidiary of such first Person, except to the
extent of the amount of dividends or other distributions actually paid or made
to such first Person or any of its Subsidiaries by such other Person during such
period (subject in the case of a dividend or distribution received by a
Subsidiary of such first Person, to the limitations contained in clause (iv)
above); (vi) any interest income resulting from loans or investments in
Affiliates, other than cash interest income actually received; (vii) charges
relating to the Transactions or the offering of the 10% Notes and (viii) the
cumulative effect of a change in accounting principles.
 
     'Consolidated Net Worth' of any Person means, at any date, all amounts that
would, in conformity with GAAP, be included under shareholders' equity on a
consolidated balance sheet of such Person as at such date less (to the extent
otherwise included therein) any amounts attributable to Redeemable Stock.
 
     'Credit Agreement' means the credit agreement, dated as of July 26, 1996,
among ISP, certain of its Subsidiaries, the financial institutions named therein
and The Chase Manhattan Bank, as agent thereunder, as the same may be amended or
supplemented.
 
     'Custodian' means any receiver, trustee, assignee, liquidator, sequestrator

or similar official under any Bankruptcy Law.
 
     'Debt' of any Person means, without duplication, (i) the principal in
respect of (A) indebtedness of such Person for money borrowed and (B)
indebtedness evidenced by notes, debentures, bonds or other similar instruments
for the payment of which such Person is responsible or liable (other than those
payable to government agencies to defer the payment of workers' compensation
liabilities, taxes, assessments or other obligations, and provided in the
ordinary course of business of such Person); (ii) all Capital Lease Obligations
of such Person; (iii) all obligations of such Person issued or assumed as the
deferred purchase price of property, all conditional sale obligations of such
Person and all obligations of such Person under any title retention agreement
(but excluding trade accounts payable and other accrued current liabilities
arising in the ordinary course of business); (iv) all obligations of such Person
for the reimbursement of any obligor on any letter of credit, bankers'
acceptance or similar credit transaction (other than obligations with respect to
letters of credit securing obligations (other than obligations described in (i)
through (iii) above) entered into in the ordinary course of business of such
Person to the extent such letters of credit are not drawn upon or, if and to the
extent drawn upon, such drawing is reimbursed no later than the third business
day following receipt by such Person of a demand for reimbursement following
payment on the letter of credit); (v) all obligations of the type referred to in
clauses (i) through (iv) of other Persons and all dividends of other Persons for
the payment of which, in either case, such
 
                                       70
<PAGE>
Person is responsible or liable, directly or indirectly, as obligor, guarantor
or otherwise, including guarantees of such obligations and dividends; and (vi)
all obligations of the type referred to in clauses (i) through (v) of other
Persons secured by any Lien on any property or asset of such Person (whether or
not such obligation is assumed by such Person), the amount of such obligation
being deemed to be the lesser of the value of such property or assets or the
amount of the obligation so secured.
 
     'Default' means any event which is, or after notice or passage of time or
both would be, an Event of Default.
 
     'EBITDA' means, with respect to any Person, for any period, the
Consolidated Net Income of such Person for such period, adjusted to the extent
deducted in calculating such Consolidated Net Income by adding back (without
duplication): (i) income tax expense of such Person and its Subsidiaries accrued
in accordance with GAAP for such period (other than income taxes attributable to
extraordinary items or other items excluded from the definition of Consolidated
Net Income), (ii) Consolidated Interest Expense of such Person, (iii)
depreciation expense, (iv) amortization expense and (v) minority interest in any
Recourse Subsidiary that is not a Wholly-Owned Subsidiary but is otherwise
consolidated in the financial statements of such Person, but only so long as
such Subsidiary is consolidated with such Person for such period for U.S.
federal income tax purposes.
 
     'Exchange Act' means the Securities Exchange Act of 1934, as amended from
time to time, and the rules and regulations of the Commission thereunder.
 

     'Existing Management Agreement' means the Amended and Restated Management
Agreement dated as of March 3, 1992 by and among GAF and certain of its
Subsidiaries as amended through the Issue Date.
 
     'Generally Accepted Accounting Principles' or 'GAAP' means generally
acceptable accounting principles set forth in the opinions and pronouncements of
the Accounting Principles Board of the American Institute of Certified Public
Accountants and statements and pronouncements of the Financial Accounting
Standards Board.
 
     'GAF' means GAF Corporation, a Delaware corporation, and its successors.
 
     'Granules Contracts' means (i) the Supply Agreement dated as of January 1,
1995 between ISP Technologies Inc. and BMCA, as amended by amendment dated as of
December 31, 1995, and (ii) the letter dated November 9, 1995 from ISP Mineral
Products Inc. to USI.
 
     'Guarantee' by any Person means any obligation, contingent or otherwise, of
such Person directly or indirectly guaranteeing any Debt or other obligation,
contingent or otherwise, of any other Person and, without limiting the
generality of the foregoing, any obligation, direct or indirect, contingent or
otherwise, of such Person (i) to purchase or pay (or advance or supply funds for
the purchase or payment of) such Debt or other obligation of such other Person
(whether arising by virtue of participation arrangements, by agreement to keep
well, to purchase assets, goods, securities or services, to take-or-pay, or to
maintain financial statement conditions or otherwise) or (ii) entered into for
the purpose of assuring the obligee of such Debt or other obligation in any
other manner of the payment thereof or to protect such obligee against loss in
respect thereof (in whole or in part), provided, however, that the term
'guarantee' shall not include endorsements for collection or deposit in the
ordinary course of business. The term 'Guarantee' used as a verb has a
corresponding meaning.
 
     'Incur' means incur, create, assume, Guarantee or otherwise become liable;
and the terms 'incurred' and 'incurrence' having meanings correlative to the
foregoing.
 
     'Investment' means any direct or indirect advance, loan (other than
advances or loans to customers in the ordinary course of business, which are
recorded, in accordance with GAAP, at the time made as accounts receivable on
the balance sheet of the Person making such advance or loan) or other extension
of credit or capital contribution to (by means of any transfer of cash or other
property to others or any payment for property or services for the account or
use of others), or any purchase or acquisition of Capital Stock, bonds, notes,
debentures or other securities Issued by, any other Person.
 
     'ISP' means International Specialty Products Inc., a Delaware corporation,
and its successors.
 
     'ISP Subsidiaries' means ISP and its Subsidiaries.
 
                                       71
<PAGE>
     'Issue' means issue, assume, Guarantee, incur or otherwise become liable

for; provided, however, that any Debt or Capital Stock of a Person existing at
the time such Person becomes a Subsidiary of another Person (whether by merger,
consolidation, acquisition or otherwise) shall be deemed to be Issued by such
Subsidiary at the time it becomes a Subsidiary of such other Person.
 
     'Issue Date' means the date of original issuance of the Old Notes.
 
     'Lien' means any lien, mortgage, charge, pledge, security interest, or
other encumbrance of any kind (including any conditional sale or other title
retention agreement and any lease in the nature thereof).
 
     'Linden Dividend' means the payment of a dividend or distribution in
respect of the Company's Common Stock of the assets comprising the Linden
Property or of the shares of Capital Stock of a Subsidiary of the Company all or
substantially all of the assets of which consist of the Linden Property.
 
     'Linden Property' means that property consisting of approximately 140 acres
(40 acres developed) located in Union County, New Jersey at the foot of South
Wood Avenue, Linden and owned by ISP Environmental Services Inc., which is the
site of a former chemicals manufacturing facility of ISP.
 
     'Long-Term Debt' of any Person means outstanding long-term debt securities
of such Person (or, in the event that such Person has no outstanding long-term
debt securities, a credit facility of such Person) that (i) is unsecured, (ii)
not subordinated in right of payment to any other Debt of such Person and (iii)
is not guaranteed and does not have credit support provided by any other Person
(other than, in the case of Long-Term Debt of any ISP Subsidiary, any ISP
Subsidiary).
 
     'Moody's' means Moody's Investors Service, Inc. or its successor.
 
     'Net Cash Proceeds' means, with respect to any Asset Sale, the proceeds in
the form of cash or Cash Equivalents, including payments in respect of deferred
payment obligations when received in the form of cash or Cash Equivalents,
received by the Company or any of its Subsidiaries from such Asset Sale net of
(a) reasonable out-of-pocket expenses and fees relating to such Asset Sale
(including, without limitation, legal, accounting and investment banking fees
and sales commissions), (b) taxes paid or payable ((1) including, without
limitation, income taxes reasonably estimated to be actually payable as a result
of any disposition of property within two years of the date of disposition,
including under any tax sharing arrangements, and (2) after taking into account
any reduction in tax liability due to available tax credits or deductions
applicable to the transaction), (c) a reasonable reserve for the after-tax cost
of any indemnification obligations (fixed and/or contingent) attributable to
seller's indemnities to the purchaser undertaken by the Company or any of its
Subsidiaries in connection with such Asset Sale and (d) repayment of Debt that
is required to be repaid in connection with such Asset Sale, under agreements
governing such Debt or Asset Sale.
 
     'New Management Agreement' means the Existing Management Agreement as
amended to add the Company as a party thereto.
 
     'Non-Recourse Debt' of any Person means Debt or the portion of Debt (i) as
to which neither GAF, the Company nor any of its Recourse Subsidiaries (A)

provides credit support (including any undertaking, agreement or instrument
which would constitute Debt), (B) is directly or indirectly liable or (C)
constitutes the lender and (ii) no default with respect to which (including any
rights which the holders thereof may have to take enforcement action against the
assets of a Non-Recourse Subsidiary) would permit (upon notice, lapse of time or
both) any holder of any other Debt of such Person or its Recourse Subsidiaries
to declare a default on such other Debt or cause the payment thereof to be
accelerated or payable prior to its Stated Maturity.
 
     'Non-Recourse Subsidiary' of any Person means a Subsidiary (A) which has
been designated as such by the Board of Directors of such Person, (B) which has
not acquired any assets directly or indirectly from GAF, the Company or any of
its Subsidiaries other than at fair market value, including by the receipt of
Capital Stock of such Non-Recourse Subsidiary, provided, however, that if any
such acquisition or series of related acquisitions involves assets having a
value in excess of $2,000,000, such acquisition or series of related
acquisitions shall be approved by a majority of the members of the Board of
Directors of the Company in a Board Resolution which shall set forth that such
acquisitions are being, or have been, made at fair market value, and (C) which
has no Debt other than Non-Recourse Debt. Subsidiaries of Non-Recourse
Subsidiaries shall be deemed Non-Recourse Subsidiaries.
 
                                       72
<PAGE>
     'Obligations' means (a) the full and punctual payment of the principal of,
and interest on, the Notes when due, whether at maturity, by acceleration, by
redemption or otherwise, and all other monetary obligations of the Company under
the Indenture and the Notes and (b) the full and punctual performance of all
other obligations of the Company under the Indenture and the Notes.
 
     'Permitted Holders' means (i) Samuel J. Heyman, his heirs, administrators,
executors and entities of which a majority of the Voting Stock is owned by
Samuel J. Heyman, his heirs, administrators or executors and (ii) any Person
controlled, directly or indirectly, by Samuel J. Heyman or his heirs,
administrators or executors.
 
     'Permitted Lien' means:
 
          (1) Liens for taxes, assessments and governmental charges to the
     extent not required to be paid under the Indenture;
 
          (2) statutory Liens of landlords and carriers, warehousemen,
     mechanics, suppliers, materialmen, repairmen or other like Liens arising in
     the ordinary course of business and with respect to amounts not yet
     delinquent or being contested in good faith by an appropriate process of
     law, and for which a reserve or other appropriate provision, if any, as
     shall be required by GAAP shall have been made;
 
          (3) pledges or deposits in the ordinary course of business to secure
     lease obligations or non-delinquent obligations under workers'
     compensation, unemployment insurance or similar legislation;
 
          (4) Liens to secure the performance of public statutory obligations
     that are not delinquent, appeal bonds, performance bonds or other

     obligations of a like nature (other than for borrowed money);
 
          (5) easements, rights-of-way, restrictions, minor defects or
     irregularities in title and other similar charges or encumbrances not
     interfering in any material respect with the business of the Company and
     its Subsidiaries taken as a whole;
 
          (6) Liens in favor of customs and revenue authorities arising as a
     matter of law to secure payment of nondelinquent customs duties in
     connection with the importation of goods;
 
          (7) judgment and attachment Liens not giving rise to a Default or
     Event of Default;
 
          (8) leases or subleases granted to others not interfering in any
     material respect with the business of the Company and its Subsidiaries,
     taken as a whole;
 
          (9) Liens encumbering deposits made in the ordinary course of business
     to secure nondelinquent obligations arising from statutory, regulatory,
     contractual or warranty requirements of the Company or its Subsidiaries for
     which a reserve or other appropriate provision, if any, as shall be
     required by GAAP shall have been made;
 
          (10) any interest or title of a lessor in the property subject to any
     lease, whether characterized as capitalized or operating other than any
     such interest or title resulting from or arising out of default by the
     Company or any of its Subsidiaries of its obligations under any such lease
     which is material;
 
          (11) Liens arising from filing UCC financing statements for
     precautionary purposes in connection with true leases or conditional sales
     of personal property that are otherwise permitted under the Indenture and
     under which the Company or any of its Subsidiaries is lessee;
 
          (12) broker's Liens securing the payment of commissions and management
     fees in the ordinary course of business;
 
          (13) Liens on cash and Cash Equivalents posted as margin pursuant to
     the requirements of any bona fide hedge agreement relating to interest
     rates, foreign exchange or commodities listed on public exchanges, but only
     to the extent such Liens are required from customers generally (regardless
     of creditworthiness) in accordance with customary market practice;
 
          (14) Liens on cash collateralizing reimbursement obligations in
     respect of letters of credit issued for the account of the Company or any
     of its Subsidiaries in the ordinary course of business (other than letters
     of credit issued as credit support for any Debt);
 
                                       73
<PAGE>
          (15) Liens arising in respect of accounts receivable arising as a
     result of non-recourse sales thereof;
 

          (16) Liens arising by reason of consignment sales of inventory in the
     ordinary course of business; and
 
          (17) Liens on stock or assets of any Non-Recourse Subsidiary securing
     Debt owing by such Non-Recourse Subsidiary.
 
     'Person' means any individual, corporation, partnership, joint venture,
incorporated or unincorporated association, joint-stock company, trust,
unincorporated organization or government or other agency or political
subdivision thereof or other entity of any kind.
 
     'Preferred Stock,' as applied to the Capital Stock of any corporation,
means Capital Stock of any class or classes (however designated) which is
preferred as to the payment of dividends, or as to the distribution of assets
upon any voluntary or involuntary liquidation or dissolution of such
corporation, over shares of Capital Stock of any other class of such
corporation. Preferred Stock of any Person shall include Redeemable Stock of
such Person.
 
     'Purchase Money Obligation' of any Person means any Debt secured by a Lien
on assets related to the business of such Person, and any additions and
accessions thereto or replacements thereof, which are purchased or constructed
by such Person at any time after the Issue Date; provided, however, that (i) the
aggregate outstanding principal amount of such Debt (determined on a per asset
basis in the case of any additions, accessions or replacements) shall not at any
time exceed 100% of the purchase price to such Person of the related assets or
(ii) such Debt shall be with recourse solely to the assets so purchased or
acquired, any additions and accessions thereto or replacements thereof and any
proceeds therefrom.
 
     'Ratings Event' means any of the following:
 
          (i) the rating of ISP's Long-Term Debt being below Baa3 (in the case
     of the rating by Moody's) and below BB+ (in the case of the rating by S&P);
     or
 
          (ii) at any time that ISP's Long-Term Debt is rated below Baa3 by
     Moody's, the rating of ISP's Long-Term Debt being placed on credit watch
     for a ratings downgrade below BB+ by S&P; or
 
          (iii) at any time that ISP's Long-Term Debt is rated below BB+ by S&P,
     the rating of ISP's Long-Term Debt being placed on credit watch for a
     ratings downgrade below Baa3 by Moody's.
 
     'Recourse Subsidiaries,' of any Person, means all Subsidiaries of such
Person other than Non-Recourse Subsidiaries of such Person.
 
     'Redeemable Stock' means, with respect to any Person, Capital Stock of such
Person that by its terms or otherwise (x) is required, directly or indirectly,
to be redeemed on or prior to the ninetieth day after the Stated Maturity of the
applicable Notes, (y) is redeemable or puttable, directly or indirectly, at the
option of the holder thereof at any time on or prior to the ninetieth day after
the Stated Maturity of the applicable Notes, or (z) is exchangeable or
convertible into another security (other than a security that is not itself

Redeemable Stock).
 
     'Refinance' means, in respect of any Debt, to refinance, extend, renew,
refund, repay, prepay, redeem, defease or retire, or to issue Debt in exchange
or replacement for, such Debt. 'Refinanced' and 'Refinancing' shall have
correlative meanings.
 
     'Refinancing Debt' means Debt Issued to Refinance, any other Debt;
provided, however, that (i) the amount of the Debt so Issued shall not exceed
the principal amount or the accreted value (in the case of Debt Issued at a
discount) of the Debt so Refinanced plus, in each case, the reasonable costs
incurred by the issuer in connection with such Refinancing, (ii) the Average
Life and Stated Maturity of the Debt so Issued shall equal or exceed that of the
Debt so Refinanced, (iii) the Debt so Issued shall not rank senior in right of
payment to the Debt being Refinanced, (iv) if the Debt being Refinanced does not
bear interest in cash prior to a specified date, the Refinancing Debt shall not
bear interest in cash prior to such specified date, (v) if the Debt being
Refinanced is a Purchase Money Obligation, the Refinancing Debt shall not be
secured by any assets not securing the Debt so Refinanced or improvements or
additions thereto, or replacements thereof, and (vi) the obligors with respect
to the Refinancing Debt shall not include any persons who were not obligors
(including predecessors thereof) with respect to the Debt being Refinanced.
 
                                       74

<PAGE>
     'Restricted Investment' means, with respect to the Company or any of its
Subsidiaries, an Investment by such Person in an Affiliate of the Company;
provided, however, that the following shall not be Restricted Investments:
 
          (a) any Investment by the Company or any ISP Subsidiary in any
     Unrestricted Affiliate; and
 
          (b) any Investment by the Company or any of its Subsidiaries in (x)
     the Company or any of its Recourse Subsidiaries or (y) any such Affiliate
     that becomes, as a result of such Investment, a Recourse Subsidiary of the
     Company.
 
     'Restricted Payment' means (i) the declaration or making of any dividend or
of any other payment or distribution (other than dividends, payments or
distributions payable solely in shares of the Company's Capital Stock other than
Redeemable Stock) on or with respect to the Company's Capital Stock (other than
Redeemable Stock) and (ii) any payment on account of the purchase, redemption,
retirement or other acquisition for value of the Company's Capital Stock (other
than Redeemable Stock); provided, however, that the Linden Dividend shall not be
deemed to be a Restricted Payment.
 
     'Restricted Security' has the meaning set forth in Rule 144(a)(3) under the
Securities Act.
 
     'S&P' means Standard & Poor's Rating Services or its successor.
 
     'Securities Act' means the Securities Act of 1933, as amended from time to
time, and the rules and regulations of the Commission thereunder.
 
     'Significant Subsidiary' means (i) any Recourse Subsidiary of the Company
which at the time of determination either (A) had assets which, as of the date
of the Company's most recent quarterly consolidated balance sheet, constituted
at least 5% of the Company's total assets on a consolidated basis as of such
date, in each case determined in accordance with GAAP, or (B) had revenues for
the 12-month period ending on the date of the Company's most recent quarterly
consolidated statement of income which constituted at least 5% of the Company's
total revenues on a consolidated basis for such period, or (ii) any Recourse
Subsidiary of the Company which, if merged with all Defaulting Subsidiaries (as
defined below) of the Company, would at the time of determination either (A)
have had assets which, as of the date of the Company's most recent quarterly
consolidated balance sheet, would have constituted at least 10% of the Company's
total assets on a consolidated basis as of such date or (B) have had revenues
for the 12-month period ending on the date of the Company's most recent
quarterly consolidated statement of income which would have constituted at least
10% of the Company's total revenues on a consolidated basis for such period
(each such determination being made in accordance with GAAP). 'Defaulting
Subsidiary' means any Recourse Subsidiary of the Company with respect to which
an event described under clause (6), (7), or (8) under 'Events of Default' has
occurred and is continuing.
 
     'Specified Agreements' means (i) the Tax Sharing Agreements (but, after a
company leaves the applicable consolidated group, only with respect to the
indemnities that survive thereunder), (ii) the Existing Management Agreement and

the New Management Agreement, (iii) the Granules Contracts and (iv) the
Indemnification Agreement and other similar indemnification agreements in effect
prior to the Issue Date.
 
     'Specified Subsidiaries' means Subsidiaries of the Company other than ISP
Subsidiaries.
 
     'Spin Off' means the consummation of the transactions described under
'--The Spin Off Transactions,' substantially on the terms described therein.
 
     'Stated Maturity' when used with respect to any Senior Note or any
installment of interest thereon, means the date specified in such Note as the
fixed date on which the principal of such Note or such installment of interest
is due and payable, and when used with respect to any other Debt, means the date
specified in the instrument governing such Debt as the fixed date on which the
principal of such Debt or any installment of interest is due and payable.
 
     'Subsidiary' means, with respect to any Person at any time of
determination, (i) a corporation a majority of whose Capital Stock with voting
power, under ordinary circumstances, to elect directors is at the time, directly
or indirectly, owned by such Person, by one or more Subsidiaries of such Person
or by such Person and one or more Subsidiaries thereof or (ii) any other Person
(other than a corporation) in which such Person, one or more Subsidiaries
thereof or such Person and one or more Subsidiaries thereof, directly or
indirectly, at the date of
 
                                       75
<PAGE>
determination thereof has at least majority ownership interest and the power to
direct the policies, management and affairs thereof. For purposes of this
definition, any director's qualifying shares or investments by foreign nationals
mandated by applicable law shall be disregarded in determining the ownership of
a Subsidiary.
 
     'Tax Sharing Agreements' means, collectively, the tax sharing agreements
described under 'Tax Sharing Agreement.'
 
     'TIA' means the Trust Indenture Act of 1939, as amended, as in effect on
the date hereof.
 
     'Treasury Yield' means the yield to maturity at the time of computation of
United States Treasury securities with a constant maturity (as compiled and
published in the most recent Federal Reserve Statistical Release H.15 (519)
which has become publicly available at least two business days prior to the
applicable redemption date (or, if such Statistical Release is no longer
published, any publicly available source of similar data)) most nearly equal to
the then remaining Average Life of the applicable Notes; provided, however, that
if the Average Life of such Notes is not equal to the constant maturity of a
United States Treasury security for which a weekly average yield is given, the
Treasury Yield shall be obtained by linear interpolation (calculated to the
nearest one-twelfth of a year) from the weekly average yields of United States
Treasury securities for which such yields are given, except that if the average
life of such Notes is less than one year, the weekly average yield on actually
traded United States Treasury securities adjusted to a constant maturity of one

year shall be used.
 
     'Unrestricted Affiliate' means any Person (other than any Subsidiary of the
Company) controlled (as defined in the definition of 'Affiliate') by the Company
in which no Affiliate of the Company (other than (i) so long as ISP is a
Recourse Subsidiary of the Company, ISP or any of its Wholly-Owned Recourse
Subsidiaries, (ii) any director or officer of the Company or any of its
Subsidiaries (so long as such Person is not also a director or officer of GAF or
any of its Affiliates (other than the Company and its Subsidiaries, except for
Non-Recourse Subsidiaries in which GAF has an interest other than through the
Company)) and (iii) another Unrestricted Affiliate under this paragraph (a)) has
an Investment.
 
     'U.S. Government Obligations' means money or direct non-callable
obligations of the United States of America for the payment of which the full
faith and credit of the United States is pledged.
 
     'USI' means U.S. Intec, Inc., a Texas corporation, and its successors.
 
     'Voting Stock' means, with respect to any Person, Capital Stock of any
class or kind normally entitled to vote in the election of the board of
directors or other governing body of such Person.
 
     'Wholly-Owned Recourse Subsidiary' of any Person means a Wholly-Owned
Subsidiary of such Person that is a Recourse Subsidiary of such Person.
 
     'Wholly-Owned Subsidiary' means a Subsidiary all the Capital Stock of which
(other than directors' qualifying shares) is owned by the applicable corporation
or another Wholly-Owned Subsidiary of the applicable corporation.
 
CERTAIN CALCULATIONS
 
     All financial calculations shall be made as if the Spin Off occurred as of
the Issue Date.
 
CERTAIN COVENANTS
 
     Each Indenture contains, among others, the following covenants:
 
     Limitation on Debt and Preferred Stock of the Company and ISP
Subsidiaries.  (a) The Company shall not Issue, directly or indirectly, any Debt
or any Preferred Stock unless, at the time of such Issuance and after giving
effect thereto, (i) no Default or Event of Default shall have occurred and be
continuing and (ii) the Consolidated EBITDA Coverage Ratio of the Company for
the period of its most recently completed four consecutive fiscal quarters
ending at least 45 days prior to the date such Debt is Issued is at least 2.00
to 1.00.
 
     (b) The Company shall not permit any ISP Subsidiary (so long as such ISP
Subsidiary is a Subsidiary of the Company) to Issue, directly or indirectly, any
Debt or any Preferred Stock unless, at the time of such Issuance and after
giving effect thereto, (i) no Default or Event of Default shall have occurred
and be continuing and (ii)
 

                                       76
<PAGE>
the Consolidated EBITDA Coverage Ratio of ISP for the period of its most
recently completed four consecutive fiscal quarters ending at least 45 days
prior to the date such Debt is Issued is at least 2.00 to 1.00.
 
     (c) Notwithstanding the foregoing, the Company and ISP Subsidiaries may
Issue the following:
 
          (1) Debt Issued pursuant to the Credit Agreement or any Refinancing
     Debt thereof in an aggregate principal amount outstanding at any time not
     to exceed $500,000,000;
 
          (2) Debt or Preferred Stock of the Company or any of its Subsidiaries
     Issued to and held by (i) ISP or any of its Wholly-Owned Recourse
     Subsidiaries, or (ii) the Company or any of its Wholly-Owned Recourse
     Subsidiaries; provided, however, that (x) any subsequent transfer of such
     Debt or such Preferred Stock to any Person not permitted by the foregoing
     or (y) any Wholly-Owned Recourse Subsidiary of ISP or of the Company that
     holds such Debt or Preferred Stock ceasing to be a Wholly-Owned Recourse
     Subsidiary of ISP or of the Company, as the case may be, shall be deemed,
     in each case, to constitute the Issuance of such Debt or such Preferred
     Stock by the Company or such ISP Subsidiary, as the case may be;
 
          (3) Purchase Money Obligations, including Refinancing Debt thereof, in
     an aggregate amount outstanding at any time not to exceed $30,000,000;
 
          (4) Acquired Debt;
 
          (5) Debt outstanding on the Issue Date (including, without limitation,
     the Old Notes) and the New Notes;
 
          (6) Refinancing Debt Issued to Refinance any Debt permitted by clauses
     (2)-(5) above;
 
          (7) Non-Recourse Debt of a Non-Recourse Subsidiary of ISP and (y)
     Guarantees of Non-Recourse Debt of any Non-Recourse Subsidiary of ISP which
     Guarantees are recourse only to the stock of such Non-Recourse Subsidiary;
 
          (8) Preferred Stock (other than Redeemable Stock) of the Company;
 
          (9) so long as no Default or Event of Default has occurred and is
     continuing and no Ratings Event has occurred and is continuing, Debt of any
     ISP Subsidiary; and
 
          (10) Debt (other than Debt described in clauses (1) through (7) and
     (9) above) in an aggregate principal amount outstanding at any time not to
     exceed $50,000,000.
 
     (d) To the extent the Company or any ISP Subsidiary Guarantees any Debt of
the Company or any ISP Subsidiary, such Guarantee and such Debt will be deemed
to be the same Debt and only the amount of the Debt will be deemed to be
outstanding. If the Company or an ISP Subsidiary Guarantees any Debt of a Person
that, subsequent to the Issuance of such Guarantee, becomes an ISP Subsidiary,

such Guarantee and the Debt so Guaranteed shall be deemed to be the same Debt
which shall be deemed to have been Issued when the Guarantee was Issued and
shall be deemed to be permitted to the extent the Guarantee was permitted when
Issued.
 
     Limitation on Debt and Preferred Stock of Specified Subsidiaries.  (a) The
Company shall not permit any Specified Subsidiary (so long as such Specified
Subsidiary is a Subsidiary of the Company) to Issue, directly or indirectly, any
Debt or any Preferred Stock unless, at the time of such Issuance and after
giving effect thereto, (i) no Default or Event of Default shall have occurred
and be continuing and (ii) the Consolidated EBITDA Coverage Ratio of the
Specified Subsidiaries (determined on a combined basis) for its most recently
completed four consecutive fiscal quarter period ending at least 45 days prior
to the date such Debt is Issued is at least 2.00 to 1.00.
 
     (b) Notwithstanding the foregoing, Specified Subsidiaries may Issue the
following:
 
          (1) Debt or Preferred Stock of any Specified Subsidiary Issued to and
     held by any Wholly-Owned Recourse Subsidiary of such Specified Subsidiary
     or the Company or any of its Wholly-Owned Recourse Subsidiaries; provided,
     however, that (x) any transfer of such Debt or such Preferred Stock to any
     Person not permitted by the foregoing or (y) such Wholly-Owned Recourse
     Subsidiary ceasing to be a Wholly-Owned Recourse Subsidiary of such
     Specified Subsidiary or of the Company, as the case may be, shall, in each
 
                                       77
<PAGE>
     case, be deemed to constitute the Issuance of such Debt or such Preferred
     Stock by such Specified Subsidiary;
 
          (2) Purchase Money Obligations in an aggregate amount outstanding at
     any time not to exceed $50,000,000;
 
          (3) Acquired Debt;
 
          (4) Debt outstanding on the Issue Date;
 
          (5) Refinancing Debt Issued to Refinance any Debt permitted by clauses
     (1)-(4) above;
 
          (6) (x) Non-Recourse Debt of a Non-Recourse Subsidiary of any
     Specified Subsidiary and (y) Guarantees of Non-Recourse Debt of
     Non-Recourse Subsidiaries which Guarantees are recourse only to the stock
     of such Non-Recourse Subsidiary; and
 
          (7) Debt (other than Debt described in clauses (1)-(6) above) in an
     aggregate principal amount outstanding at any time not to exceed
     $50,000,000.
 
     (c) To the extent any Specified Subsidiary Guarantees any Debt of any other
Specified Subsidiary, such Guarantee and such Debt will be deemed to be the same
Debt and only the amount of the Debt will be deemed to be outstanding. If a
Specified Subsidiary Guarantees any Debt of a Person that, subsequent to the

Issuance of such Guarantee, becomes a Specified Subsidiary, such Guarantee and
the Debt so Guaranteed shall be deemed to be the same Debt which shall be deemed
to have been Issued when the Guarantee was Issued and shall be deemed to be
permitted to the extent the Guarantee was permitted when Issued.
 
     Prohibition on Debt and Capital Stock of Intermediate Parents of
ISP.  Notwithstanding paragraphs (a) and (b) of the 'Limitation on Debt and
Preferred Stock of Specified Subsidiaries' covenant the Company shall not permit
any of its Subsidiaries (other than, subject to the 'Limitation on Debt and
Preferred Stock of the Company and ISP Subsidiaries' covenant, ISP Subsidiaries)
that, directly or indirectly, owns any Capital Stock or Debt of any ISP
Subsidiary to Issue any Debt or Capital Stock other than Debt or Capital Stock
Issued to and held by (x) so long as ISP is a Recourse Subsidiary of the
Company, ISP or any of its Wholly-Owned Recourse Subsidiaries or (y) the
Company.
 
     Limitation on Restricted Payments and Restricted Investments.  (a) The
Company shall not make, and shall not permit any of its Subsidiaries to make,
directly or indirectly, any Restricted Payment or Restricted Investment at any
time on or after the Issue Date if, at the time of such Restricted Payment or
Restricted Investment or immediately after giving effect thereto:
 
          (1) a Default or an Event of Default shall have occurred and be
     continuing;
 
          (2) the Company is not able to incur at least $1.00 of additional Debt
     under paragraph (a) of the 'Limitation on Debt and Capital Stock of the
     Company and ISP Subsidiaries' covenant; or
 
          (3) the aggregate amount of Restricted Payments made since June 30,
     1996 (the 'Applicable Date') and the aggregate amount of Restricted
     Investments made since the Applicable Date and then outstanding (the amount
     expended for such purposes, if other than in cash, shall be the fair market
     value of such property as determined by the Board of Directors of the
     Company in good faith as of the date of payment or investment) shall exceed
     the sum of:
 
             (i) 50% of the cumulative Consolidated Net Income (or minus 100% of
        the cumulative Consolidated Net Loss) of the Company accrued during the
        period beginning on the Applicable Date and ending on the last day of
        the fiscal quarter for which financial information has been made
        publicly available by the Company but ending no more than 135 days prior
        to the date of such Restricted Payment or Restricted Investment
        (treating such period as a single accounting period);
 
             (ii) 100% of the net cash proceeds, including the fair market value
        of property other than cash as determined by the Board of Directors of
        the Company in good faith, as evidenced by a Board Resolution, received
        by the Company from any Person (other than a Subsidiary of the Company)
        from the Issuance and sale subsequent to the Applicable Date of Capital
        Stock of the Company (other than Redeemable Stock) or as a capital
        contribution;
 
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<PAGE>
             (iii) 100% of the net cash proceeds received by the Company from
        any Person (other than a Subsidiary of the Company) from the exercise of
        options or warrants on Capital Stock of the Company (other than
        Redeemable Stock);
 
             (iv) 100% of the net cash proceeds received by the Company from the
        conversion into Capital Stock (other than Redeemable Stock) of
        convertible Debt or convertible Preferred Stock issued and sold (other
        than to a Subsidiary of the Company) since the Applicable Date; and
 
             (v) $30,000,000.
 
     The designation by the Company or any of its Subsidiaries of a Subsidiary
as a Non-Recourse Subsidiary shall be deemed to be the making of a Restricted
Investment by the Company in an amount equal to the outstanding Investments made
by the Company and its Subsidiaries in such person being designated a Non-
Recourse Subsidiary at the time of such designation.
 
     (b) The foregoing paragraph (a) shall not prevent the following, as long as
no Default or Event of Default shall have occurred and be continuing (or would
result therefrom other than pursuant to paragraph (a)):
 
          (1) the making of any Restricted Payment or Restricted Investment
     within 60 days after (x) the date of declaration thereof or (y) the making
     of a binding commitment in respect thereof; provided that at such date of
     declaration or commitment such Restricted Payment or Restricted Investment
     complied with paragraph (a); or
 
          (2) any Restricted Payment or Restricted Investment made out of the
     net cash proceeds received by the Company from the substantially concurrent
     sale of its Common Stock (other than to a Subsidiary of the Company);
     provided, however, that such net cash proceeds so utilized shall not be
     included in paragraph (a)(3) in determining the amount of Restricted
     Payments or Restricted Investments the Company could make under paragraph
     (a), and Restricted Payments or Restricted Investments made pursuant to
     this clause (2) shall not be included in determining the amount of
     Restricted Payments or Restricted Investments made or then outstanding
     under paragraph (a)(3); or
 
          (3) repurchases of Capital Stock of the Company, in each case from
     employees of the Company or any of its Subsidiaries (other than any
     Permitted Holder); provided, however, that the aggregate amount of
     Restricted Payments made under this clause shall not exceed $3,000,000 in
     any fiscal year; provided, further, however, that the amount of Restricted
     Payments made pursuant to this clause (3) shall not be included in
     determining the amount of Restricted Payments made under paragraph (a)(3).
 
     Limitation on Liens.  (a) The Company shall not, and shall not permit any
of its Specified Subsidiaries to, directly or indirectly, incur or suffer to
exist any Liens (other than Permitted Liens) upon their respective properties or
assets whether owned on the Issue Date or acquired after such date, or on any
income or profits therefrom, other than the following:
 

          (1) Liens securing intercompany Debt permitted by paragraph (b)(1)
     under the 'Limitation on Debt and Capital Stock of Specified Subsidiaries'
     covenant;
 
          (2) Liens existing on the Issue Date;
 
          (3) Purchase money Liens on assets of the Company and its Specified
     Subsidiaries or improvements or additions thereto existing or created
     within 180 days after the time of acquisition of or improvement or addition
     to such assets, or replacements thereof; provided that (i) such
     acquisition, improvement or addition is otherwise permitted by the
     applicable Indenture, (ii) the principal amount of Debt (including Debt in
     respect of Capitalized Lease Obligations) secured by each such Lien in each
     asset shall not exceed the cost (including all such Debt secured thereby,
     whether or not assumed) of the item subject thereto, and such Liens shall
     attach solely to the particular item of property so acquired, improved or
     added, and any additions or accessions thereto, or replacements thereof,
     and (iii) the aggregate amount of Debt secured by Liens permitted by this
     clause (3) shall not at any one time exceed $50,000,000;
 
          (4) Liens securing Acquired Debt; provided, however, that (i) any such
     Lien secured the Acquired Debt at the time of the incurrence of such
     Acquired Debt by the Company or by one of its Specified Subsidiaries and
     such Lien and Acquired Debt were not incurred by the Company or any of its
     Specified Subsidiaries or
 
                                       79
<PAGE>
     by the Person being acquired or from whom the assets were acquired in
     connection with, or in anticipation of, the incurrence of such Acquired
     Debt by the Company or by one of its Specified Subsidiaries, and (ii) any
     such Lien does not extend to or cover any property or assets of the Company
     or of any of its Specified Subsidiaries other than the property or assets
     that secured the Acquired Debt prior to the time such Debt became Acquired
     Debt of the Company or of one of its Specified Subsidiaries;
 
          (5) Liens to secure Refinancing of any Debt secured by Liens described
     in clauses (1)-(4) above and (6) below; provided that (i) the Refinancing
     does not increase the principal amount of Debt being so Refinanced and (ii)
     the Lien of the Refinancing Debt does not extend to any asset not securing
     the Debt being Refinanced or improvements or additions thereto, or
     replacements thereof; and
 
          (6) Liens on assets of the Company and its Specified Subsidiaries
     (other than the Liens described above), provided that such Liens only
     secure Debt of the Company and its Specified Subsidiaries in an aggregate
     amount not to exceed at any one time outstanding $50,000,000.
 
     Prohibition on Certain Transactions.  The Company shall not, and shall not
permit any of its Subsidiaries to, enter, directly or indirectly, into, or
suffer to exist, any transaction or series of transactions (including, without
limitation, any loan, advance or investment or any purchase, sale, lease or
exchange of property or the rendering of any service) with GAF or any of its
Subsidiaries. The foregoing shall not prohibit any transaction permitted by

paragraph (b)(5) or (c) under the 'Limitation on Transactions with Affiliates'
covenant.
 
     Limitation on Transactions with Affiliates.  (a) The Company shall not
enter, and shall not permit any of its Subsidiaries to enter, directly or
indirectly, into any transaction or series of related transactions with any
Affiliate of the Company, including, without limitation, any loan, advance or
investment or any purchase, sale, lease or exchange of property or the rendering
of any service, unless the terms of such transaction or series of transactions
are set forth in writing and at least as favorable as those available in a
comparable transaction in arms-length dealings from an unrelated Person;
provided, however, that (i) if any such transaction or series of related
transactions (other than any purchase or sale of inventory in the ordinary
course of business) involves aggregate payments or other consideration in excess
of $2,000,000, such transaction or series of related transactions shall be
approved (and the value of any non-cash consideration shall be determined) by a
majority of those members of the Board of Directors of the Company or such
Subsidiary, as the case may be, having no personal stake in such business,
transaction or transactions; and (ii) in the event that such transaction or
series of related transactions (other than any purchase or sale of inventory in
the ordinary course of business) involves aggregate payments or other
consideration in excess of $20,000,000 (with the value of any non-cash
consideration being determined by a majority of those members of the Board of
Directors of the Company or such Subsidiary, as the case may be, having no
personal stake in such business, transaction or transactions), the Company or
such Subsidiary, as the case may be, shall have also received a written opinion
from a nationally recognized investment banking firm that such transaction or
series of related transactions are fair to the shareholders, in their capacity
as such, of the Company or such Subsidiary from a financial point of view and
such opinion has been delivered to the Trustee; provided, further, in the event
that the Board of Directors of the Company or the Subsidiary, as the case may
be, proposing to engage in a transaction or series of related transactions
described in the preceding proviso does not have any members having no personal
stake in such business, transaction or transactions, the Company or such
Subsidiary may enter into such transaction or series of transactions if the
Company or such Subsidiary, as the case may be, shall have received the written
opinion of a nationally recognized investment banking firm that the terms
thereof, from a financial point of view, are fair to the shareholders of the
Company or such Subsidiary, in their capacity as such (the determination as to
the value of any non-cash consideration referred to in the preceding proviso to
be made by such investment banking firm), and such opinion shall have been
delivered to the Trustee.
 
     (b) The foregoing paragraph (a) shall not prevent the following:
 
          (1) any transaction between a Subsidiary of the Company and its own
     employee stock ownership or benefit plan;
 
          (2) any transaction with an officer or director of the Company or any
     of its Subsidiaries entered into in the ordinary course of business
     (including compensation or employee benefit arrangements with any such
     officer or director);
 
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<PAGE>
          (3) any business or transaction by an ISP Subsidiary or the Company
     with an Unrestricted Affiliate;
 
          (4) transactions permitted by the 'Limitation on Investments in
     Non-Recourse Subsidiaries by ISP Subsidiaries' covenant;
 
          (5) payments made or actions taken pursuant to any of the Specified
     Agreements (or any new agreement referred to in paragraph (c) below), as
     any such Specified Agreement (or new agreement) is, subject to paragraph
     (c) below, amended, modified, extended or waived from time to time;
 
          (6) the making of a Restricted Payment or Restricted Investment
     otherwise permitted by paragraph (a) of the 'Limitation on Restricted
     Payments and Restricted Investments' covenant or those transactions
     specifically permitted by paragraph (b) of the 'Limitation on Restricted
     Payments and Restricted Investments' covenant;
 
          (7) (i) transactions between or among Non-Recourse Subsidiaries of
     ISP, and (ii) transactions between or among Non-Recourse Subsidiaries of
     any Specified Subsidiary; or
 
          (8) (i) so long as ISP is a Recourse Subsidiary of the Company,
     transactions between or among ISP, its Recourse Subsidiaries and the
     Company, and (ii) transactions between or among any Specified Subsidiary
     and its Recourse Subsidiaries.
 
     (c) The Company will not, and will not permit any of its Subsidiaries to
amend, modify, extend or waive any provision of any of the Specified Agreements
in any manner which is significantly adverse to the Company or the Holders (it
being understood that an extension or modification of either of the Granules
Contracts (or any similar granules purchase contract) on terms at least as
favorable to the Company as those available at the time of the extension or
modification (or any such new agreement) in a comparable transaction in
arms-length dealings with an unrelated Person shall not be deemed significantly
adverse to the Company or the Holders).
 
     Limitation on Investments in Non-Recourse Subsidiaries by ISP
Subsidiaries.  The Company shall not, and shall not permit any ISP Subsidiary
(so long as such ISP Subsidiary is a Subsidiary of the Company) to, make
Investments in Non-Recourse Subsidiaries of ISP if, after giving effect thereto,
the cumulative aggregate amount (the amount so expended, if other than in cash,
to be determined by the Board of Directors of ISP, as evidenced by a Board
Resolution) of such Investments, as of the date of the Investment, made by the
Company and ISP Subsidiaries would exceed 20% of the Consolidated Net Worth of
ISP.
 
     Limitation on Dividend and Other Payment Restrictions Affecting
Subsidiaries.  The Company shall not, and shall not permit any of its Recourse
Subsidiaries to, directly or indirectly, create or otherwise cause to exist or
become effective any encumbrance or restriction on the ability of any such
Subsidiary to (a) pay dividends or make any other distributions on its Capital
Stock or pay any Debt owed to the Company or any of its Subsidiaries, (b) make
loans or advances to, or Issue any Guarantee for the benefit of, the Company or

any of its Subsidiaries, (c) transfer any of its properties or assets to the
Company or any of its Subsidiaries or (d) incur or suffer to exist Liens in
favor of the Holders, except for such encumbrances or restrictions existing
under or by reason of the following:
 
          (1) applicable law;
 
          (2) the Indentures;
 
          (3) customary provisions restricting subletting or assignment of any
     lease or license or other commercial agreement;
 
          (4) any instrument governing Acquired Debt of any Person, which
     encumbrance or restriction is not applicable to any Person, or the
     properties or assets of any Person, other than such Person and its
     Subsidiaries, or the property or assets of such Person and its
     Subsidiaries, so acquired;
 
          (5) Liens specifically permitted by the 'Limitation on Liens'
     covenant; provided that such Liens and the terms governing such Liens do
     not, directly or indirectly, restrict the Company or its Subsidiaries from
     granting other Liens, except as to the assets subject to such Liens;
 
          (6) the Credit Agreement or other Debt existing on the Issue Date and
     any Refinancing of the Credit Agreement or any such other Debt; provided
     that the terms and conditions of any such Refinancing
 
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<PAGE>
     agreements relating to the terms described under clauses (a)-(d) above are
     no less favorable to the Company and its Subsidiaries than those contained
     in the agreements governing the Debt being Refinanced; and
 
          (7) covenants contained in agreements governing Debt of ISP
     Subsidiaries; provided, however, that such covenants shall not prohibit the
     ISP Subsidiaries from, directly or indirectly, paying dividends or making
     loans or advances to the Company in an aggregate amount less than the
     positive difference, if any, between (i) the sum of (A) $25,000,000 and (B)
     50% of the cumulative Consolidated Net Income (or minus 100% of the
     Consolidated Net Loss) of ISP for the period beginning on the first day of
     the fiscal quarter during which such Debt was issued, and (ii) the
     aggregate amount of Restricted Payments and Restricted Investments made by
     ISP Subsidiaries since such date.
 
     Limitation on Asset Sales.  (a) The Company shall not, and shall not permit
any of its Subsidiaries, directly or indirectly, to consummate an Asset Sale
unless:
 
          (1) the Company or such Subsidiary, as the case may be, receives
     consideration (including non-cash consideration, whose fair market value
     shall be determined in good faith by the Board of Directors of the Company
     or such Subsidiary, as evidenced by a Board Resolution) at the time of such
     Asset Sale at least equal to the fair market value of the assets sold or
     otherwise disposed of (as determined in good faith by the Board of

     Directors, as evidenced by a Board Resolution);
 
          (2) at least 75% of the consideration received by the Company or such
     Subsidiary, as the case may be, shall be cash or Cash Equivalents;
     provided, however, that this clause (2) shall not prohibit any Asset Sale
     for which the Company or such Subsidiary, as the case may be, receives 100%
     of the consideration, directly or through the acquisition of Capital Stock
     of a Person, in operating assets; and
 
          (3) in the case of an Asset Sale by the Company or any of its
     Subsidiaries, the Company or such Subsidiary, as the case may be, shall
     apply the Net Cash Proceeds of such Asset Sale within one year of receipt
     thereof, (i) to invest in the businesses that the Company and its Recourse
     Subsidiaries are engaged in at the time of such Asset Sale or any like or
     related business, (ii) to pay or satisfy Debt or Preferred Stock of the
     Company or such Subsidiary, as the case may be, and/or (iii) to offer to
     purchase the Notes (on a pro rata basis) in a tender offer at a redemption
     price equal to 100% of the principal thereof plus accrued interest thereon
     to the date of redemption; provided, however, that the Company may defer
     making any such offer until the aggregate Net Cash Proceeds from Asset
     Sales to be applied pursuant to clause (3)(iii) equal or exceed
     $20,000,000; provided, further, however, that (i) the Company and its
     Subsidiaries may retain up to $5,000,000 of Net Cash Proceeds from Asset
     Sales in any twelve-month period (without complying with clause (3)), and
     (ii) any Asset Sale that would result in a Change of Control shall not be
     governed by this covenant but shall be governed by the provisions described
     under 'Change of Control Put and Call.'
 
     Investment Company Act.  The Company shall not take any action that would
require it or any of its Subsidiaries to register as an investment company under
the Investment Company Act of 1940.
 
     Securities and Exchange Commission Reports. At all times from and after the
earlier of (i) the date of the commencement of the Exchange Offers or the
effectiveness of the Shelf Registration Statement contemplated by the
Registration Rights Agreements and (ii) the date that is six months after the
Issue Date, in either case, whether or not the Company is then required to file
reports with the Commission, the Company shall file with the Commission all such
reports and other information as would be required to be filed with the
Commission under the Exchange Act. The Company shall supply to each Holder and
to any other Person who reasonably requests in writing, without cost, copies of
such reports or other information. In addition, the Company shall, at its cost,
deliver to each Holder, and a prospective purchaser designated by such Holder,
from and after the earlier of the dates referred to in clauses (i) and (ii)
above, quarterly and annual reports substantially equivalent to those which
would be required under the Exchange Act if at the time of such request the
Company is not a reporting company under Section 13 or Section 15(d) of the
Exchange Act. The Company also will comply with the other provisions of TIA
Section314(a).
 
     So long as any of the Notes remain outstanding, the Company shall cause
each annual, quarterly and other financial report mailed or otherwise furnished
by it generally to public stockholders to be filed with the Trustee and mailed
to the Holders at their addresses appearing in the register of Notes maintained

by the Registrar, in each case at the time of such mailing or furnishing to such
stockholders.
 
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<PAGE>
MERGER, ETC.
 
     The Company shall not consolidate with or merge with or into or sell,
assign, transfer or lease all or substantially all of its properties and assets
(either in one transaction or series of related transactions) to any Person,
unless:
 
          (1) the Company shall be the continuing Person, or the resulting,
     surviving or transferee Person (if other than the Company) shall be a
     corporation organized and existing under the laws of the United States or
     any State thereof or the District of Columbia and shall expressly assume,
     by an indenture supplemental hereto, executed and delivered to the Trustee,
     in form reasonably satisfactory to the Trustee, all the obligations of the
     Company under the Notes and the Indenture, and the Indenture shall remain
     in full force and effect;
 
          (2) immediately before and immediately after giving effect to such
     transaction (and treating any Debt which becomes an obligation of the
     resulting, surviving or transferee Person or any of its Subsidiaries as a
     result of such transaction as having been issued by such Person or such
     Subsidiary at the time of such transaction), no Default or Event of Default
     shall have occurred and be continuing; and
 
          (3) immediately after giving effect to such transaction, the
     resulting, surviving or transferee Person shall have a Consolidated Net
     Worth in an amount which is not less than the Consolidated Net Worth of the
     Company immediately prior to such transaction.
 
     In connection with any consolidation, merger, sale, assignment, transfer or
lease contemplated by this covenant, the Company shall deliver, or cause to be
delivered, to the Trustee, in form and substance reasonably satisfactory to the
Trustee, an officers' certificate and an opinion of counsel, each stating that
such consolidation, merger, sale, assignment, transfer or lease and the
supplemental indenture in respect thereto comply with this covenant and that all
conditions precedent herein provided for relating to such transaction have been
complied with.
 
     Upon any consolidation or merger or any sale, assignment, transfer or lease
of all or substantially all of the assets of the Company in accordance with the
foregoing provisions, the successor corporation formed by such consolidation or
into which the Company is merged or to which such sale, assignment, transfer or
lease is made, shall succeed to, and be substituted for, and may exercise every
right and power of, the Company under the Indentures, with the same effect as if
such successor corporation had been named as the Company therein, and, except in
the case of a lease, the Company will be discharged from all obligations and
covenants under the Indentures and the Notes.
 
EVENTS OF DEFAULT
 

     An 'Event of Default' occurs under an Indenture if:
 
          (1) the Company defaults in the payment of interest on, or Additional
     Interest (if any) with respect to, any Note issued pursuant to such
     Indenture when the same becomes due and payable and the default continues
     for a period of 30 days;
 
          (2) (i) the Company defaults in the payment of the principal of any
     Note issued pursuant to such Indenture when the same becomes due and
     payable at maturity or otherwise or (ii) the Company fails to redeem or
     repurchase Notes issued pursuant to such Indenture when required pursuant
     to such Indenture or the Notes;
 
          (3) the Company fails to comply with the provisions described under
     'Merger, Etc.' contained in such Indenture;
 
          (4) the Company fails to comply for 30 days after notice with any of
     its obligations under 'Change of Control Put and Call' and 'Certain
     Covenants' contained in such Indenture;
 
          (5) the Company fails to comply for 60 days after notice with its
     other agreements contained in the Indenture or the Notes issued pursuant to
     such Indenture (other than those referred to in clauses (1)-(4) above);
 
                                       83
<PAGE>
          (6) Debt of the Company or any Significant Subsidiary is not paid
     within any applicable grace period or is accelerated by the holders thereof
     because of a default and the total principal amount of the portion of such
     Debt that is unpaid or accelerated exceeds $15,000,000 or its foreign
     currency equivalent and such default continues for 5 days after notice;
 
          (7) the Company or any of its Significant Subsidiaries (A) admits in
     writing its inability to pay its debts generally as they become due, (B)
     commences a voluntary case or proceeding under any Bankruptcy Law with
     respect to itself, (C) consents to the entry of a judgment, decree or order
     for relief against it in an involuntary case or proceeding under any
     Bankruptcy Law, (D) consents to the appointment of a Custodian of it or for
     substantially all of its property, (E) consents to or acquiesces in the
     institution of a bankruptcy or an insolvency proceeding against it, (F)
     makes a general assignment for the benefit of its creditors, or (G) takes
     any corporate action to authorize or effect any of the foregoing; and
 
          (8) any judgment or order for the payment of money in excess of
     $15,000,000 in the aggregate is rendered against the Company or any
     Significant Subsidiary of the Company and (i) there is a period of 60 days
     following the entry of such judgment or order during which such judgment or
     order is not discharged, waived or the execution thereof stayed and such
     default continues for 10 days after the notice specified below or (ii)
     foreclosure proceedings therefor have begun and have not been stayed within
     five days of the commencement of such foreclosure proceeding.
 
     A Default under clauses (4), (5), (6) or (8) is not an Event of Default
until the Trustee or the Holders of at least 25% in aggregate principal amount

of the outstanding issue of Notes issued pursuant to the applicable Indenture
notify the Company in writing of the Default, and the Company does not cure the
Default within the time specified in such clause after receipt of such notice.
Such notice shall be given by the Trustee if so requested in writing by the
Holders of at least 25% in aggregate principal amount of such outstanding Notes.
When a Default under clause (4), (5), (6) or (8) is cured or remedied within the
specified period, it ceases to exist.
 
     If an Event of Default (other than an Event of Default with respect to the
Company specified in clause (7) above) occurs and is continuing, the Trustee, by
written notice to the Company, or the Holders of at least 25% in aggregate
principal amount of such outstanding issue of Notes issued pursuant to the
applicable Indenture, by written notice to the Company and the Trustee, may
declare the principal of and accrued interest on all such Notes then outstanding
to be due and payable (the 'Default Amount'). Upon a declaration of
acceleration, such amount shall be due and payable immediately.
 
     If an Event of Default with respect to the Company specified in clause (7)
above occurs, the Default Amount shall ipso facto become and be immediately due
and payable without any declaration or other act on the part of the Trustee or
any Holder.
 
     The Holders of a majority in aggregate principal amount at maturity of the
applicable issue of Notes then outstanding, by written notice to the Trustee and
the Company, may rescind an acceleration with respect to such Notes and its
consequences if (i) all existing Defaults and Events of Default, other than the
non-payment of the principal of such Notes which has become due solely by such
declaration of acceleration, have been cured or waived, (ii) to the extent the
payment of such interest is lawful, interest on overdue principal, which has
become due otherwise than by such declaration of acceleration, has been paid and
(iii) the rescission would not conflict with any judgment or decree of a court
of competent jurisdiction.
 
     Notwithstanding any other provision of the applicable Indenture, if an
Event of Default occurs and is continuing and the Holders are entitled to
payment as a result of acceleration, the Trustee may pursue any available remedy
by proceeding at law or in equity to collect the payment of principal of and/or
interest on the applicable issue of Notes or to enforce the performance of any
provision of such Notes or the applicable Indenture.
 
     The Trustee may maintain a proceeding even if it does not possess any of
the Notes or does not produce any of them in the proceeding. A delay or omission
by the Trustee or any Holder in exercising any right or remedy accruing upon an
Event of Default shall not impair the right or remedy or constitute a waiver of
or acquiescence in the Event of Default. No remedy is exclusive of any other
remedy. All available remedies are cumulative.
 
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<PAGE>
     Subject to certain provisions of the applicable Indenture, the Holders of a
majority in aggregate principal amount of the outstanding Notes governed thereby
by notice to the Trustee may waive an existing Default or Event of Default and
its consequences, except a Default or Event of Default in payment of principal
or interest on any Note as specified in clauses (1) and (2) above. When a

Default or Event of Default is waived, it is cured and ceases to exist.
 
     The Holders of a majority in aggregate principal amount of the applicable
issue of Notes may direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or exercising any trust or
power conferred on it. However, the Trustee may refuse to follow any direction
that conflicts with law or the applicable Indenture or that the Trustee
determines may be unduly prejudicial to the rights of another Holder as such, or
that may subject the Trustee to personal liability. The Trustee may take any
other action deemed proper by the Trustee which is not inconsistent with such
direction.
 
     A Holder may not pursue any remedy with respect to an Indenture or the
Notes except under specified circumstances.
 
     If a Default occurs under an Indenture and is continuing and if it is known
to the Trustee, the Trustee shall mail to each Holder of Notes issued thereunder
notice of the Default within 90 days after it occurs. Except in the case of a
Default in the payment of the principal of or interest on any Note, the Trustee
may withhold notice if and so long as a committee of its Trust Officers in good
faith determines that the withholding of such notice is in the interests of the
Holders of the applicable Notes.
 
DISCHARGE; DEFEASANCE
 
     When (i) the Company delivers to the Trustee all outstanding Notes issued
under an Indenture (other than replaced Notes) for cancellation or (ii) all
outstanding Notes issued under an Indenture have become due and payable, and the
Company irrevocably deposits with the Trustee money sufficient to pay at
maturity all such outstanding Notes, including interest thereon (other than
replaced Notes), and if in either case the Company pays all other sums payable
hereunder by the Company, then the Indenture governing such Notes shall, except
with respect to certain matters, cease to be of further effect. The Trustee
shall acknowledge satisfaction and discharge of such Indenture on demand of the
Company accompanied by an officers' certificate and an opinion of counsel as to
the satisfaction of all conditions to such satisfaction and discharge of such
Indenture and at the cost and expense of the Company.
 
     Subject to the provisions set forth in the applicable Indenture, the
Company may at any time terminate (i) all its obligations under the Notes issued
under an Indenture and the applicable Indenture ('legal defeasance'), or (ii)
its obligations under certain of the covenants under such Indenture ('covenant
defeasance').
 
     The Company may exercise its legal defeasance option or its covenant
defeasance option only if:
 
          (1) the Company irrevocably deposits in trust with the Trustee money
     or U.S. Government Obligations for the payment of principal and interest,
     if any, on the applicable issue of Notes to maturity or redemption, as the
     case may be;
 
          (2) the Company delivers to the Trustee a certificate from a
     nationally recognized firm of independent accountants expressing their

     opinion that the payments of principal and interest when due and without
     reinvestment on the deposited U.S. Government Obligations plus any
     deposited money without investment will provide cash at such times and in
     such amounts as will be sufficient to pay principal and interest when due
     on all the applicable Notes to maturity or redemption, as the case may be;
 
          (3) no Default or Event of Default has occurred and is continuing on
     the date of such deposit and after giving effect thereto;
 
          (4) the deposit does not constitute a default under any other
     agreement binding on the Company;
 
          (5) the Company delivers to the Trustee an opinion of counsel to the
     effect that the trust resulting from the deposit does not constitute, or is
     qualified as, a regulated investment company under the Investment Company
     Act of 1940;
 
                                       85
<PAGE>
          (6) the Company delivers to the Trustee an opinion of counsel stating
     that the Holders will not recognize income, gain or loss for federal income
     tax purposes as a result of such deposit and defeasance and will be subject
     to federal income tax on the same amount and in the same manner and at the
     same times as would have been the case if such deposit and defeasance had
     not occurred, and, in the case of legal defeasance only, such opinion of
     counsel shall be based on a ruling of the Internal Revenue Service or other
     change in applicable federal income tax law; and
 
          (7) the Company delivers to the Trustee an officers' certificate and
     an opinion of counsel, each stating that all conditions precedent to the
     defeasance and discharge of the Notes have been complied with.
 
     Notwithstanding the foregoing provisions of this Section, the conditions
set forth in the foregoing paragraphs (2), (3), (4), (5), (6) and (7) need not
be satisfied so long as, at the time the Company makes the deposit described in
paragraph (1), (i) no payment or bankruptcy Default under the applicable
Indenture has occurred and is continuing on the date of such deposit and after
giving effect thereto and (ii) either (x) a notice of redemption has been mailed
providing for redemption of all the applicable Notes 30 days after such mailing
and the provisions of the applicable Indenture with respect to such redemption
shall have been complied with or (y) the Stated Maturity of all of the
applicable Notes will occur within 30 days. If the conditions of the preceding
sentence are satisfied the Company shall be deemed to have exercised its
covenant defeasance option.
 
AMENDMENTS, SUPPLEMENTS AND WAIVERS
 
     The Company, when authorized by resolution of its Board of Directors, and
the Trustee may amend an Indenture or the Notes issued pursuant thereto with the
written consent of the Holders of a majority in aggregate principal amount of
the applicable issue of Notes then outstanding, and the Holders of a majority in
aggregate principal amount of the applicable issue of Notes then outstanding by
written notice to the Trustee may waive future compliance by the Company with
any provision of such Indenture or such Notes.

 
     Notwithstanding the foregoing, without the consent of each Holder affected,
an amendment or waiver, may not:
 
          (1) change the stated maturity of the principal of, or any installment
     of interest on, any Note or reduce the principal amount thereof, the rate
     of interest thereon or any premium payable upon the redemption thereof, or
     change the coin or currency in which any Note or any premium or the
     interest thereon is payable, or impair the right to institute suit for the
     enforcement of any such payment after the stated maturity thereof (or, in
     the case of redemption, on or after the redemption date);
 
          (2) reduce the percentage in principal amount of the outstanding
     Notes, the consent of the Holders of which is required for any supplemental
     indenture or the consent of such Holders is required for any waiver of
     compliance with provisions of the applicable Indenture or Defaults
     hereunder and their consequences provided for in such Indenture;
 
          (3) modify any of the provisions relating to supplemental indentures
     requiring the consent of Holders or relating to the waiver of past defaults
     or relating to the waiver of covenants, except to increase any such
     percentage of outstanding Notes required for such actions or to provide
     that certain other provisions of the applicable Indenture cannot be
     modified or waived without the consent of each Holder affected thereby;
 
          (4) waive a default in the payment of the principal of or interest on
     any Note or modify or waive the Company's obligation to repurchase Notes
     under the provisions described under 'Change of Control' or 'Certain
     Covenants--Limitation on Asset Sales';
 
          (5) except as otherwise permitted by the provisions described under
     'Merger, Etc.', consent to the assignment or transfer by the Company of any
     of its rights and obligations under the Indenture;
 
          (6) make any change in the amendment and waiver provisions, provisions
     relating to waiver of past defaults or provisions relating to rights of
     holders to receive payment; or
 
          (7) change the time at which any Note must be redeemed or repaid in
     accordance with the terms of the applicable Indenture and the Notes.
 
                                       86
<PAGE>
     It shall not be necessary for the consent of the Holders to approve the
particular form of any proposed amendment, supplement or waiver, but it shall be
sufficient if such consent approves the substance thereof. Any amendment, waiver
or consent shall be deemed effective upon receipt by the Trustee of the
necessary consents and shall not require execution of any supplemental indenture
to be effective.
 
     Except as otherwise provided above, the Holders of a majority in aggregate
principal amount of the applicable issue of Notes then outstanding may waive
compliance in a particular instance by the Company with any provisions of the
applicable Indenture or such Notes.

 
     The Company shall not, and shall not permit any of its Subsidiaries to,
directly or indirectly, pay or cause to be paid any fee, interest or other
amount to any Holders in connection with any consent, waiver or amendment to an
Indenture or the Notes governed thereby, unless such fee, interest or other
amount is offered or agreed to be paid to all Holders who are given the same
opportunity to so consent, waive or agree to amend and who, in fact, so consent,
waive or agree to amend.
 
GOVERNING LAW
 
     The Indentures and the Notes are governed by and will be construed in
accordance with, the laws of the State of New York.
 
   
                       FEDERAL INCOME TAX CONSIDERATIONS
    
 
   
     The following summary of the material federal income tax consequences to
tendering holders of Old Notes of (i) the exchange of Old Notes for New Notes
and (ii) the ownership and disposition of New Notes, reflects the opinion of
Weil, Gotshal & Manges LLP, counsel for the Company.
    
 
     This summary is based upon provisions of the Internal Revenue Code of 1986,
as amended (the 'Code'), Treasury Regulations promulgated thereunder (including
temporary regulations), administrative rulings and judicial decisions now in
effect, all of which are subject to change, possible with retroactive effect.
This summary does not discuss all aspects of federal income taxation that may be
relevant to a particular holder in light of such holder's individual investment
circumstances or to certain types of holders subject to special treatment under
the federal income tax laws (for example, dealers in securities, banks, life
insurance companies, tax-exempt organizations and foreign taxpayers and persons
who hold (or will hold) the Old Notes or New Notes as part of a 'straddle,'
'hedge' or 'conversion transaction'), nor does it discuss any aspect of state,
local or foreign taxation. The following discussion assumes that the Old Notes
and New Notes are (and will be) held by the holders thereof as 'capital assets'
within the meaning of Section 1221 of the Code.
 
     THE FOLLOWING SUMMARY IS INCLUDED HEREIN FOR GENERAL INFORMATIONAL PURPOSES
ONLY. ACCORDINGLY, EACH HOLDER OF OLD NOTES SHOULD CONSULT WITH SUCH HOLDER'S
OWN TAX ADVISOR AS TO THE PARTICULAR TAX CONSEQUENCES TO SUCH HOLDER OF
PARTICIPATION IN THE EXCHANGE OFFER, AND THE OWNERSHIP AND DISPOSITION OF NEW
NOTES, INCLUDING THE APPLICABILITY AND EFFECT OF ANY STATE, LOCAL OR FOREIGN TAX
LAWS.
 
FEDERAL INCOME TAX CONSEQUENCES OF TENDERING OLD NOTES
 
     The exchange of Old Notes for New Notes pursuant to the Exchange Offers
should not constitute an exchange for federal income tax purposes. Accordingly,
the Exchange Offers should have no federal income tax consequences to holders of
Old Notes. Except for the immediately succeeding paragraph, the balance of this
discussion assumes that the exchange of Old Notes for New Notes will not

constitute an exchange for federal income tax purposes.
 
     If, contrary to the above conclusion, the exchange of Old Notes for New
Notes constitutes an exchange for federal income purposes, both the Old Notes
and the New Notes should constitute 'securities' for federal income tax purposes
(which determination generally is made by reference to the initial terms of the
debt instrument, with debt instruments with initial terms of more than five
years generally being treated as securities) and, thus, a holder of Old Notes
should recognize no gain or loss on the consummation of the Exchange Offers.
 
                                       87
<PAGE>
FEDERAL INCOME TAX CONSEQUENCES OF OWNING NEW NOTES
 
STATED INTEREST
 
     Interest on a New Note should be taxable to a U.S. holder as ordinary
interest income at the time it accrues or is received in accordance with such
holder's method of accounting for U.S. federal income tax purposes.
 
SALE OR REDEMPTION
 
     The sale, exchange, redemption (including pursuant to an offer by the
Company) or other disposition of New Notes generally will be a taxable event for
federal income tax purposes. A holder generally will recognize gain or loss
equal to the difference between (i) the amount of cash plus the fair market
value of any property received upon such sale, exchange, redemption or other
taxable disposition of a New Note (other than in respect of accrued interest
thereon) and (ii) the holder's adjusted tax basis in such debt instrument (other
than in respect of accrued interest thereon). Subject to the possible
application of the market discount rules discussed below, such gain or loss will
be capital gain or loss and would be long-term capital gain or loss if the New
Notes were held by the holder for the applicable period at the time of such sale
or other disposition.
 
MARKET DISCOUNT
 
     Except as discussed below, gain recognized on the disposition of New Notes
having accrued market discount will be treated as ordinary income, and not
capital gain, to the extent of the accrued market discount, provided the amount
of market discount thereon exceeds a de minimis amount. In general, upon the
disposition of a 'market discount' bond, any gain recognized by a holder is
treated as ordinary income to the extent of accrued market discount thereon.
Market discount is defined generally as the excess of (i) the 'stated redemption
price at maturity' of a debt obligation less any unamortized original issue
discount over (ii) the tax basis of the debt obligation in the hands of the
holder immediately after its acquisition.
 
     If a holder of New Notes having accrued market discount disposes of such
New Notes in any transaction other than a sale, exchange or redemption (e.g., a
gift), such holder will be deemed to have realized an amount equal to the fair
market value of such new Notes and will be required to recognize as ordinary
income any accrued market discount thereon. See 'Sale or Redemption' above for
the general consequences of a sale, exchange or redemption. Partial principal

payments (if any) on such New Notes also would be includable as ordinary income
to the extent of any accrued market discount on such New Notes. A holder of New
Notes having accrued market discount also may be required to defer the deduction
of all or a portion of the interest on any indebtedness incurred or maintained
to purchase or carry such New Notes until they are disposed of in a taxable
transaction.
 
     A holder of New Notes having accrued market discount may elect to include
the market discount in income as it accrues. This election would apply to all
market discount obligations acquired by the electing holder on or after the
first day of the first taxable year to which the election applies and may be
revoked only with the consent of the Service. If a holder of New Notes elects to
include market discount in income, the above-discussed rules with respect to
ordinary income recognition resulting from sale and certain other disposition
transactions and to deferral of interest deductions would not apply.
 
BOND PREMIUM
 
     If the initial tax basis of a holder in any New Notes exceeds the 'amount
payable on maturity' (such excess being the 'bond premium'), the holder may
elect to amortize the bond premium over the period from the acquisition date of
such New Notes to their maturity date (or an earlier call date, if using such
earlier date would result in a smaller amortization deduction) and, except as
Treasury Regulations may otherwise provide, reduce the amount of interest
included in income in respect of such New Notes by such amount.
 
     A holder who elects to amortize bond premium must reduce his adjusted basis
in such New Notes by the amount of such allowable amortization. An election to
amortize bond premium would apply to amortizable bond premium on all taxable
bonds held at or acquired after the beginning of the holder's taxable year as to
which the election is made, and may be revoked subsequently only with the
consent of the Service.
 
                                       88
<PAGE>
BACKUP WITHHOLDING
 
     Under the Code, a holder of Old Notes or New Notes may be subject, under
certain circumstances, to 'backup withholding' at a 31% rate with respect to
payments of interest or the gross proceeds from the sale, exchange or redemption
of such notes. This withholding generally applies only if the holder (i) fails
to furnish his social security or other taxpayer identification number ('TIN')
within a reasonable time after the request therefor, (ii) furnishes an incorrect
TIN, (iii) fails to report properly interest or dividends, or (iv) fails, under
certain circumstances, to provide a certified statement, signed under penalty of
perjury, that the TIN provided is his correct number and that he is not subject
to backup withholding. Any amount withheld from a payment to a holder under the
backup withholding rules is allowable as a credit against such holder's federal
income tax liability, provided that the required information is furnished to the
Service. Holders of Old Notes and New Notes should consult their tax advisors as
to their qualification for exemption from withholding and the procedure for
obtaining such an exemption.
 
                              PLAN OF DISTRIBUTION

 
     Each broker-dealer that receives New Notes for its own account pursuant to
the Exchange Offers must acknowledge that it will deliver a prospectus meeting
the requirements of the Securities Act in connection with any resales of such
New Notes. This Prospectus, as it may be amended or supplemented from time to
time, may be used by all persons subject to the prospectus delivery requirements
of the Securities Act, including broker-dealers in connection with resales of
New 9% Notes received in exchange for Old 9% Notes and in connection with
resales of New 9 3/4% Notes received for Old 9 3/4% Notes, in each case, where
such Old Notes were acquired as a result of market-making activities or other
trading activities. ISP Holdings has agreed that, for a period of 180 days after
the Expiration Date, it will make this Prospectus, as amended or supplemented,
available to any broker-dealer for use in connection with any such resale.
 
     ISP Holdings will not receive any proceeds from any sale of New Notes by
broker-dealers. New Notes received by broker-dealers for their own account
pursuant to the Exchange Offers may be sold from time to time in one or more
transactions in the over-the-counter market, in negotiated transactions, through
the writing of options on the New Notes or a combination of such methods of
resale, at market prices prevailing at the time of resale, at prices related to
such prevailing market prices or negotiated prices. Any such resale may be made
directly to purchasers or to or through brokers or dealers who may receive
compensation in the form of commissions or concessions from any such
broker-dealer and/or the purchasers of any such New Notes. Any broker-dealer
that resells New Notes that were received by it for its own account pursuant to
the Exchange Offers and any broker or dealer that participates in a distribution
of such New Notes may be deemed to be an 'underwriter' within the meaning of the
Securities Act and any profit on any such resale of New Notes and any
commissions or concessions received by any such persons may be deemed to be
underwriting compensation under the Securities Act. The Letter of Transmittal
states that by acknowledging that it will deliver and by delivering a prospectus
meeting the requirements of the Securities Act, a broker-dealer will not be
deemed to admit that it is an 'underwriter' within the meaning of the Securities
Act.
 
     For a period of 180 days after the Expiration Date, ISP Holdings will
promptly send additional copies of this Prospectus and any amendment or
supplement to this Prospectus to any broker-dealer that requests such documents
in the Letter of Transmittal. ISP Holdings has agreed to pay all expenses
incident to the Exchange Offers (including the reasonable fees and expenses of
Cahill Gordon and Reindel, counsel to Bear, Stearns & Co. Inc., the initial
purchaser of the Old 9% Notes) other than commissions or concessions of any
brokers or dealers and will indemnify holders of the Notes (including any
broker-dealers) against certain liabilities, including liabilities under the
Securities Act.
 
                                 LEGAL MATTERS
 
     Certain legal matters with respect to the validity of the issuance of the
New Notes will be passed upon for ISP Holdings by Weil, Gotshal & Manges LLP (a
limited liability partnership including professional corporations), New York,
New York. Weil, Gotshal & Manges LLP has from time to time represented, and
continues to represent, Bear, Stearns & Co. Inc. in connection with various
legal matters. Weil, Gotshal &

 
                                       89
<PAGE>
Manges LLP has from time to time represented, and may continue to represent, GAF
and certain of its affiliates (including G-I Holdings, ISP and BMCA) in
connection with certain legal matters.
 
                                    EXPERTS
 
     The consolidated financial statements and schedules of ISP Holdings as of
December 31, 1994 and 1995 and the consolidated statements of income,
shareholder's equity (deficit) and cash flows for each of the three years in the
period ended December 31, 1995 included in this Prospectus have been audited by
Arthur Andersen LLP, independent public accountants, as indicated in their
reports with respect thereto, and are included herein in reliance upon the
authority of said firm as experts in giving said reports.
 
                             AVAILABLE INFORMATION
 
     ISP, G-I Holdings and BMCA are subject to the informational requirements of
the Securities Exchange Act of 1934, as amended (the 'Exchange Act'), and in
accordance therewith file reports, proxy statements (with respect to ISP) and
other information with the Commission. The reports, proxy statements and other
information filed by ISP, G-I Holdings and BMCA with the Commission can be
inspected and copied at the public reference facilities maintained by the
Commission at Room 1024, 450 Fifth Street, N.W., Washington, D.C. 20549, and at
the Commission's Regional Offices at Seven World Trade Center, 13th Floor, New
York, New York 10048 and Citicorp Center, 500 West Madison Street, Suite 1400,
Chicago, Illinois 60601-2511. Copies of such material also can be obtained from
the Public Reference Section of the Commission, Washington, D.C. 20549 at
prescribed rates. In addition, ISP's common stock is listed on the New York
Stock Exchange and material filed by ISP can be inspected at the offices of the
New York Stock Exchange, 20 Broad Street, New York, New York 10005. Finally, the
Commission maintains an Internet web site at http://www.sec.gov that contains
reports, proxy and information statements and other information regarding
registrants that file electronically with the Commission.
 
     ISP Holdings has filed with the Commission a Registration Statement (which
term shall encompass any amendments thereto) on Form S-4 under the Securities
Act with respect to the New Notes offered hereby. This Prospectus does not
contain all information set forth in the Registration Statement and the exhibits
thereto, to which reference is hereby made. Statements made in this Prospectus
as to the contents of any contract, agreement, or other document are not
necessarily complete. With respect to each such contract, agreement, or other
document filed as an exhibit to the Registration Statement, reference is hereby
made to such exhibit for a more complete description of the matter involved, and
each such statement shall be deemed qualified in its entirety by such reference.
 
                                       90

<PAGE>
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                              ----
<S>                                                                                                           <C>
Report of Independent Public Accountants...................................................................    F-2
Consolidated Statements of Income for the three years ended December 31, 1995 and the nine months ended
  October 1, 1995 and September 29, 1996 (unaudited).......................................................    F-3
Consolidated Balance Sheets as of December 31, 1995 and as of September 29, 1996 (unaudited)...............    F-4
Consolidated Statements of Cash Flows for the three years ended December 31, 1995 and the nine months ended
  October 1, 1995 and September 29, 1996 (unaudited).......................................................    F-5
Consolidated Statements of Shareholder's Equity (Deficit) for the three years ended December 31, 1995 and
  the nine months ended September 29, 1996 (unaudited).....................................................    F-7
Notes to Consolidated Financial Statements.................................................................    F-8
Supplementary Data (unaudited):
Quarterly Financial Data (unaudited).......................................................................   F-27
</TABLE>
 
                                      F-1

<PAGE>
                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To ISP Holdings Inc.:
 
     We have audited the accompanying consolidated balance sheets of ISP
Holdings Inc. (a Delaware corporation and a wholly owned subsidiary of GAF
Corporation) and subsidiaries as of December 31, 1994 and 1995, and the related
consolidated statements of income, shareholder's equity (deficit) and cash flows
for each of the three years in the period ended December 31, 1995. These
financial statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the financial statements referred to above, appearing on
pages F-3 to F-26 of this Prospectus, present fairly, in all material respects,
the financial position of ISP Holdings Inc. and subsidiaries as of December 31,
1994 and 1995, and the results of their operations and their cash flows for each
of the three years in the period ended December 31, 1995, in conformity with
generally accepted accounting principles.
 
                                          ARTHUR ANDERSEN LLP
 
Roseland, New Jersey
August 7, 1996
(except with respect to the matter
discussed in Note 14 as to which the
date is December 9, 1996)
 
                                      F-2

<PAGE>
                               ISP HOLDINGS INC.
                       CONSOLIDATED STATEMENTS OF INCOME
 
   
<TABLE>
<CAPTION>
                                                                                             NINE MONTHS ENDED
                                                                                        ----------------------------
                                                        YEAR ENDED DECEMBER 31,         OCTOBER 1,     SEPTEMBER 29,
                                                    --------------------------------       1995            1996
                                                      1993        1994        1995      (UNAUDITED)     (UNAUDITED)
                                                    --------    --------    --------    -----------    -------------
                                                                              (THOUSANDS)
<S>                                                 <C>         <C>         <C>         <C>            <C>
Net sales........................................   $548,252    $600,047    $689,002     $ 530,334       $ 544,135
                                                    --------    --------    --------    -----------    -------------
Costs and expenses:
  Cost of products sold..........................    329,517     367,746     414,672       322,329         320,295
  Selling, general and administrative............    125,961     119,656     134,011        98,876         108,236
  Provision for restructuring....................     13,827          --          --            --              --
  Goodwill amortization..........................     13,856      13,400      13,223         9,922           9,900
                                                    --------    --------    --------    -----------    -------------
     Total costs and expenses....................    483,161     500,802     561,906       431,127         438,431
                                                    --------    --------    --------    -----------    -------------
Operating income.................................     65,091      99,245     127,096        99,207         105,704
Interest expense.................................    (24,500)    (28,676)    (33,091)      (24,821)        (21,879)
Equity in earnings of joint venture..............      2,051       2,034       5,413         2,950           4,948
Other income (expense), net......................      7,181        (119)      6,684         3,869           9,429
                                                    --------    --------    --------    -----------    -------------
Income from continuing operations before income
  taxes and extraordinary item...................     49,823      72,484     106,102        81,205          98,202
Income taxes:
  Current year provision.........................    (17,320)    (26,732)    (38,727)      (29,981)        (35,647)
  Adjustment of deferred tax liability for change
     in tax rate.................................     (2,945)         --          --            --              --
Minority interest in income of subsidiaries......     (5,737)     (8,640)    (12,306)       (9,452)        (10,802)
                                                    --------    --------    --------    -----------    -------------
Income from continuing operations before
  extraordinary item.............................     23,821      37,112      55,069        41,772          51,753
                                                    --------    --------    --------    -----------    -------------
Discontinued operations:
  Loss from discontinued operations, net of
     income taxes................................     (9,415)     (7,865)    (22,241)      (15,838)        (17,422)
  Gain on sale of discontinued operation, net of
     income taxes of $30,648.....................         --          --          --            --          43,637
                                                    --------    --------    --------    -----------    -------------
Income (loss) from discontinued operations.......     (9,415)     (7,865)    (22,241)      (15,838)         26,215
                                                    --------    --------    --------    -----------    -------------
Income before extraordinary item.................     14,406      29,247      32,828        25,934          77,968
Extraordinary items, net of income tax benefits
  of $733 and $5,016, respectively...............         --      (1,237)         --            --          (8,186)
                                                    --------    --------    --------    -----------    -------------
Net income.......................................   $ 14,406    $ 28,010    $ 32,828     $  25,934       $  69,782

                                                    --------    --------    --------    -----------    -------------
                                                    --------    --------    --------    -----------    -------------
</TABLE>
    
 
The accompanying Notes to Consolidated Financial Statements are an integral part
                              of these statements.
 
                                      F-3

<PAGE>
                               ISP HOLDINGS INC.
                          CONSOLIDATED BALANCE SHEETS
 
   
<TABLE>
<CAPTION>
                                                                           DECEMBER 31,            SEPTEMBER 29,
                                                                     -------------------------          1996
                                                                        1994           1995         (UNAUDITED)
                                                                     ----------     ---------    ------------------
                                                                                    (THOUSANDS)
<S>                                                                  <C>            <C>          <C>
                              ASSETS
Current assets:
  Cash and cash equivalents........................................  $   20,127     $   14,080       $   11,767
  Investments in trading securities................................      42,737         17,183            1,266
  Investments in available-for-sale securities.....................      14,583        114,099           94,567
  Investments in held-to-maturity securities.......................          --          4,618            4,119
  Accounts receivable, trade, less reserve of $2,292, $2,879
     and $2,916....................................................      55,585         60,327           72,764
  Accounts receivable, other.......................................       9,977         12,356           20,637
  Inventories......................................................     108,787        107,969           98,354
  Net current assets of discontinued operations....................     106,237        147,451          254,979
  Other current assets.............................................      14,572         12,920           13,726
                                                                     ----------     ----------   ------------------
Total current assets...............................................     372,605        491,003          572,179
Property, plant and equipment, net.................................     477,109        475,550          482,416
Excess of cost over net assets of businesses acquired, net of
  accumulated amortization of $78,602, $91,825 and $101,725........     443,681        430,458          420,558
Other assets.......................................................      64,146         63,378           62,135
                                                                     ----------     ----------   ------------------
Total assets.......................................................  $1,357,541     $1,460,389       $1,537,288
                                                                     ----------     ----------   ------------------
                                                                     ----------     ----------   ------------------
 
          LIABILITIES AND SHAREHOLDER'S EQUITY (DEFICIT)
Current liabilities:
  Short-term debt..................................................  $       --     $   36,199       $   22,518
  Current maturities of long-term debt.............................         890            398              361
  Loan payable to affiliate........................................      41,341         50,597           17,797
  Accounts payable.................................................      47,984         41,727           50,017
  Accrued liabilities..............................................      46,625         56,538           57,929
  Payable to affiliates, net.......................................       3,336          9,429            4,413
  Income taxes.....................................................       4,389          6,114            6,099
                                                                     ----------     ----------   ------------------
Total current liabilities..........................................     144,565        201,002          159,134
                                                                     ----------     ----------   ------------------
Long-term debt less current maturities.............................     285,397        280,254          239,760
                                                                     ----------     ----------   ------------------
Long-term note payable to affiliate................................      91,709         67,237           80,977
                                                                     ----------     ----------   ------------------
Deferred taxes.....................................................      72,955         55,743           45,452
                                                                     ----------     ----------   ------------------

Net noncurrent liabilities of discontinued operations..............     591,592        678,805          770,271
                                                                     ----------     ----------   ------------------
Other liabilities..................................................      74,310         65,458           62,224
                                                                     ----------     ----------   ------------------
Minority interest in subsidiaries..................................     112,804        113,597          117,817
                                                                     ----------     ----------   ------------------
Commitments and contingencies......................................
Shareholder's equity (deficit):
  Common stock, $.01 par value per share; 1,000 shares authorized:
     10 shares issued and outstanding..............................          --             --               --
  Additional paid-in capital.......................................      50,704         56,342          118,516
  Excess of purchase price over the adjusted historical cost of the
     predecessor company shares owned by GAF's stockholders........     (72,605)       (72,605)         (72,605)
  Retained earnings................................................          --             --            1,924
  Cumulative translation adjustment and other......................       6,110         14,556           13,818
                                                                     ----------     ----------   ------------------
     Shareholder's equity (deficit)................................     (15,791)        (1,707)          61,653
                                                                     ----------     ----------   ------------------
Total liabilities and shareholder's equity (deficit)...............  $1,357,541     $1,460,389       $1,537,288
                                                                     ----------     ----------   ------------------
                                                                     ----------     ----------   ------------------
</TABLE>
    
 
The accompanying Notes to Consolidated Financial Statements are an integral part
                              of these statements.
 
                                      F-4

<PAGE>
   
                               ISP HOLDINGS INC.
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
 
<TABLE>
<CAPTION>
                                                                                               NINE MONTHS ENDED
                                                                                          ---------------------------
                                                            YEAR ENDED DECEMBER 31,       OCTOBER 1,    SEPTEMBER 29,
                                                         ------------------------------      1995           1996
                                                           1993       1994       1995     (UNAUDITED)    (UNAUDITED)
                                                         --------   --------   --------   -----------   -------------
                                                                                 (THOUSANDS)
<S>                                                      <C>        <C>        <C>        <C>           <C>
Cash and cash equivalents, beginning period............  $ 11,162   $ 11,022   $ 20,127    $  20,127      $  14,080
                                                         --------   --------   --------   -----------   -------------
Cash provided by operating activities:
  Net income...........................................    14,406     28,010     32,828       25,934         69,782
    Adjustments to reconcile net income to net cash
      provided by operating activities:
      (Income) loss from discontinued operations.......     9,415      7,865     22,241       15,838        (18,029)
      Non-cash extraordinary charge....................        --      1,237         --           --             --
      Depreciation.....................................    28,737     32,753     35,960       26,698         28,183
      Goodwill amortization............................    13,856     13,400     13,223        9,922          9,900
      Deferred income taxes............................   (13,542)   (16,494)   (18,809)      (5,125)       (11,340)
      Provision for restructuring......................    13,827         --         --           --             --
    (Increase) decrease in working capital items.......     2,868    (11,277)    (5,105)     (13,465)        (3,015)
    Purchases of trading securities....................  (130,432)  (269,878)   (66,483)     (65,385)       (34,228)
    Proceeds from sales of trading securities..........   129,185    284,520    104,058      103,952         39,841
    (Increase) decrease in other assets................     6,586     (4,281)        56       (6,303)         1,116
    Increase (decrease) in other liabilities...........     1,847     (2,090)    (1,343)      (1,250)           810
    Proceeds from termination of interest rate swap
      agreements.......................................    25,069         --         --           --             --
    Increase (decrease) in net payable to affiliates...    10,234       (247)     6,093       (9,756)        (5,016)
    Change in cumulative translation adjustment........    (5,070)     6,694      5,561        6,470         (4,005)
    Change in minority interest in subsidiaries........     4,517     10,252     13,663       11,002         10,015
    Other, net.........................................       340     (4,556)     1,868         (843)        (1,527)
                                                         --------   --------   --------   -----------   -------------
Net cash provided by operating activities..............   111,843     75,908    143,811       97,689         82,487
                                                         --------   --------   --------   -----------   -------------
Cash provided by (used in) investing activities:
  Capital expenditures and acquisitions................   (62,858)   (31,098)   (38,934)     (26,559)       (35,669)
  Proceeds from sale of discontinued operation.........        --         --         --           --         89,464
  Other-discontinued operations.......................     1,150      4,106     28,159       27,693        (83,027)
  Purchases of available-for-sale securities...........        --       (953)  (366,200)    (228,007)      (194,126)
  Purchases of held-to-maturity securities.............        --         --     (5,592)      (5,314)        (9,534)
  Proceeds from sales of available-for-sale
    securities.........................................        --        742    257,197      134,185        227,838
  Proceeds from held-to-maturity securities............        --         --        974           --         10,033
                                                         --------   --------   --------   -----------   -------------
Net cash provided by (used in) investing activities....   (61,708)   (27,203)  (124,396)     (98,002)         4,979
                                                         --------   --------   --------   -----------   -------------
Cash provided by (used in) financing activities:

  Proceeds (repayments) from sale of accounts
    receivable.........................................    24,284     (1,052)     3,768        1,814             --
  Increase (decrease) in short-term debt...............    10,637    (12,848)    36,199       49,088        (14,013)
  Repayments of long-term debt.........................  (125,820)   (83,048)    (5,635)     (16,341)       (40,615)
  Increase (decrease) in loans from affiliate..........    46,317     66,263    (15,216)      (2,384)       (19,060)
  Subsidiary's repurchases of common stock.............        --       (327)   (16,614)     (13,965)       (10,365)
  Dividends to minority shareholders of subsidiary.....      (969)      (969)        --           --             --
  Dividends and distributions paid to parent company...   (14,406)   (27,010)   (33,637)     (27,692)       (67,996)
  Capital contribution from parent company.............     9,230     18,880      5,478           --         61,558
  Other, net...........................................       452        511        195           62            712
                                                         --------   --------   --------   -----------   -------------
Net cash used in financing activities..................   (50,275)   (39,600)   (25,462)      (9,418)       (89,779)
                                                         --------   --------   --------   -----------   -------------
Net change in cash and cash equivalents................      (140)     9,105     (6,047)      (9,731)        (2,313)
                                                         --------   --------   --------   -----------   -------------
Cash and cash equivalents, end of period...............  $ 11,022   $ 20,127   $ 14,080    $  10,396      $  11,767
                                                         --------   --------   --------   -----------   -------------
                                                         --------   --------   --------   -----------   -------------
</TABLE>
    
 
                                      F-5
<PAGE>
                               ISP HOLDINGS INC.
               CONSOLIDATED STATEMENTS OF CASH FLOWS--(CONTINUED)
<TABLE>
<CAPTION>
                                                                                               NINE MONTHS ENDED
                                                                                          ---------------------------
                                                            YEAR ENDED DECEMBER 31,       OCTOBER 1,    SEPTEMBER 29,
                                                         ------------------------------      1995           1996
                                                           1993       1994       1995     (UNAUDITED)    (UNAUDITED)
                                                         --------   --------   --------   -----------   -------------
                                                                                 (THOUSANDS)
Supplemental Cash Flow Information:
<S>                                                      <C>        <C>        <C>        <C>           <C>
Effect on cash from (increase) decrease in working
  capital items(1):
  Accounts receivable..................................  $  2,499   $(14,161)  $(10,892)   $ (20,652)     $ (20,575)
  Inventories..........................................     4,306     (5,087)     1,029        8,589          9,657
  Other current assets.................................     1,239      1,688      2,105         (291)          (725)
  Accounts payable.....................................     5,036      8,187     (5,895)      (3,677)         8,264
  Accrued liabilities..................................      (896)    (4,162)     8,389        1,477            539
  Income taxes.........................................    (9,316)     2,258        159        1,089           (175)
                                                         --------   --------   --------   -----------   -------------
    Net effect on cash from (increase) decrease in
      working capital items............................  $  2,868   $(11,277)  $ (5,105)   $ (13,465)     $  (3,015)
                                                         --------   --------   --------   -----------   -------------
                                                         --------   --------   --------   -----------   -------------
Cash paid during the period for:
  Interest (net of amount capitalized).................  $ 23,969   $ 31,140   $ 36,776    $  30,651      $  28,175
  Income taxes (including taxes paid pursuant
    to the Tax Sharing Agreement)......................    38,703     44,499     44,489       35,285         48,681
</TABLE>

 
- ------------------
 
(1) Working capital items exclude cash, restricted cash, short-term investments
    and short-term debt. Working capital acquired in connection with
    acquisitions is reflected within 'Capital expenditures and acquisitions.'
    The effects of reclassifications between noncurrent and current assets and
    liabilities are excluded from the amounts shown above. In addition, the
    (increase) decrease in accounts receivable shown above does not reflect the
    cash proceeds from the sale of certain of the Company's accounts receivable
    (see Note 5); such proceeds are reflected in cash from financing activities.
 
The accompanying Notes to Consolidated Financial Statements are an integral part
                              of these statements.

 
                                      F-6

<PAGE>
                               ISP HOLDINGS INC.
           CONSOLIDATED STATEMENTS OF SHAREHOLDER'S EQUITY (DEFICIT)
 
<TABLE>
<CAPTION>
                                                                                CAPITAL
                                                                               STOCK AND      CUMULATIVE
                                                                               ADDITIONAL     TRANSLATION
                                                                                PAID-IN       ADJUSTMENT     RETAINED
                                                                                CAPITAL       AND OTHER      EARNINGS
                                                                               ----------     ----------     --------
                                                                                            (THOUSANDS)
<S>                                                                            <C>            <C>            <C>
December 31, 1992..........................................................     $  22,625      $  7,426      $     --
  Net income...............................................................            --            --        14,406
  Translation adjustment...................................................            --        (5,070)           --
  Dividends and distributions to parent company............................            --            --       (14,406)
  Capital contribution from parent company.................................         9,230            --            --
  Change in unrealized gain on investments held by insurance subsidiary....            --        (1,863)           --
  Adjustment of unfunded pension liability.................................            --        (2,357)           --
                                                                               ----------     ----------     --------
December 31, 1993..........................................................     $  31,855      $ (1,864)     $     --
  Net income...............................................................            --            --        28,010
  Translation adjustment...................................................            --         6,694            --
  Dividends and distributions to parent company............................            --            --       (28,010)
  Capital contribution from parent company.................................        18,880            --            --
  Unrealized loss on available-for-sale securities, net of $517 income tax
     benefit...............................................................            --          (886)           --
  Change in unrealized gain on investments held by insurance subsidiary....            --          (594)           --
  Adjustment of unfunded pension liability.................................            --         2,760            --
  Effect of subsidiary's purchases of treasury stock.......................           (31)           --            --
                                                                               ----------     ----------     --------
December 31, 1994..........................................................     $  50,704      $  6,110      $     --
  Net income...............................................................            --            --        32,828
  Translation adjustment...................................................            --         5,561            --
  Dividends and distributions to parent company............................            --            --       (32,828)
  Capital contribution from parent company.................................         5,478            --            --
  Change in unrealized gains on available-for-sale securities, net of
     $1,503 income tax effect..............................................            --         2,636            --
  Adjustment of unfunded pension liability.................................            --           249            --
  Effect of exercises of subsidiary's stock options........................           160            --            --
                                                                               ----------     ----------     --------
December 31, 1995..........................................................     $  56,342      $ 14,556      $     --
  Net income (unaudited)...................................................            --            --        69,782
  Translation adjustment (unaudited).......................................            --        (4,005)           --
  Dividends and distributions to parent company (unaudited)................            --            --       (67,858)
  Capital contribution from parent company (unaudited).....................        61,558            --            --
  Change in unrealized gains on available-for-sale securities, net of
     $1,652 income tax effect (unaudited)..................................            --         3,267            --
  Effect of exercises of subsidiary's stock options (unaudited)............           396            --            --
  Effect of subsidiary's issuance of stock and options as incentives
     (unaudited)...........................................................           220            --            --
                                                                               ----------     ----------     --------

September 29, 1996 (unaudited).............................................     $ 118,516      $ 13,818      $  1,924
                                                                               ----------     ----------     --------
                                                                               ----------     ----------     --------
</TABLE>
 
The accompanying Notes to Consolidated Financial Statements are an integral part
                              of these statements.
 
                                      F-7

<PAGE>
                               ISP HOLDINGS INC.
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
 
     ISP Holdings Inc. ('ISP Holdings') is a wholly owned subsidiary of GAF
Corporation ('GAF'). ISP Holdings was formed on August 6, 1996 and 10 shares of
its common stock were issued to GAF in exchange for all of the capital stock of
G-I Holdings Inc. ('G-I Holdings'), which resulted in G-I Holdings becoming a
direct wholly-owned subsidiary of ISP Holdings. As used herein, the term
'Company' refers to ISP Holdings and its subsidiaries.
 
     The accompanying consolidated financial statements have been prepared on a
basis which retroactively reflects the formation of ISP Holdings, as discussed
above, for all periods presented. The net income for each period presented up to
the date ISP Holdings was formed has been reflected as dividends and/or
distributions to GAF. Financial information with regard to the nine months ended
October 1, 1995 and September 29, 1996 is unaudited and, in the opinion of
management, contains all adjustments necessary to present fairly the financial
position and the results of operations and cash flows of the Company for the
periods presented. All adjustments are of a normal recurring nature. The results
of operations for these periods are not necessarily indicative of the results to
be expected for the full year.
 
   
     On January 1, 1997, GAF effected a series of transactions (the 'Spin Off
Transactions') that resulted in, among other things, the capital stock of ISP
Holdings (whose principal asset is now approximately 83.5% of the issued and
outstanding capital stock of ISP) being distributed to the stockholders of GAF.
As a result of such distribution, ISP Holdings and its subsidiary, International
Specialty Products Inc. ('ISP'), are no longer direct or indirect subsidiaries
of GAF, and the assets and liabilities of other wholly owned subsidiaries of G-I
Holdings, including Building Materials Corporation of America ('BMCA'), U.S.
Intec, Inc. ('USI'), and GAF Fiberglass Corporation (formerly known as GAF
Chemicals Corporation) ('GFC'), are no longer assets and liabilities of ISP
Holdings.
    
 
     Accordingly, the results of operations and assets and liabilities of BMCA,
USI and GCC, as well as GAF Broadcasting Company, Inc. (which was sold in August
1996), have been classified as 'Discontinued Operations' within the financial
statements for all periods presented.
 
     The Company, through its subsidiary, ISP, is engaged principally in the
manufacture and sale of specialty chemicals. See Notes 11 and 12 for a
description of and financial information concerning the Company's industry
segments and foreign and domestic operations.
 
     See Notes 14 and 16 for a discussion of a subsequent event and discontinued
operations.
 
NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
  Principles of Consolidation
 

     All subsidiaries are consolidated and intercompany transactions have been
eliminated.
 
  Financial Statement Estimates
 
     The preparation of financial statements requires management to make certain
estimates. Actual results could differ from those estimates. In the opinion of
management, the financial statements herein contain all adjustments necessary to
present fairly the financial position and the results of operations and cash
flows of the Company for the periods presented. All adjustments are of a normal
recurring nature. The Company has a policy to review the recoverability of
long-lived assets and identify and measure any potential impairments. The
Company does not anticipate any changes in management estimates that would have
a material impact on operations, liquidity or capital resources, subject to the
matters discussed in Note 13 (Commitments and Contingencies).
 
  Short-term Investments
 
     The Company carries its short-term investments at market value. For
securities classified as 'trading' (including short positions), unrealized gains
and losses are reflected in income. For securities classified as
'available-for-sale', unrealized gains (losses), net of income tax effect, are
included in a separate component of shareholder's equity (deficit), 'Cumulative
translation adjustment and other,' and amounted to ($.9), $1.8 and
 
                                      F-8
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES--(CONTINUED)
   
$5.0 million as of December 31, 1994 and 1995 and September 29, 1996,
respectively. Investments classified as 'held-to-maturity' securities are
carried at amortized cost in the Consolidated Balance Sheet.
    
 
     'Other income, net' includes $6.2, $16.5, $9.3 and $13.8 million of net
realized and unrealized gains and losses on securities in 1994 and 1995 and the
first nine months of 1995 and 1996, respectively, and $10.9 million of net
realized gains in 1993. The determination of cost in computing realized gains
and losses is based on the specific identification method.
 
     During the fourth quarter of 1995, the Company redesignated certain equity
securities held long (which are offsets against short positions in certain other
securities), with a fair market value of $18.1 million, as 'trading' and
recorded unrealized gains on such securities, through the date of redesignation,
in the amount of $2.1 million as 'Other income.'
 
   
     As of December 31, 1994 and 1995 and September 29, 1996, the market value
of the Company's equity securities held long was $57.3, $132.2 and $96.4
million, respectively, and the Company had $13.1, $22 and $4.3 million,
respectively, of short positions in common stocks. As of December 31, 1994 and

1995 and September 29, 1996, the market value of the Company's held-to-maturity
securities was $0, $4.6 and $4.1 million, respectively. The market values
referred to above are based on quotations as reported by various stock exchanges
and major broker-dealers. With respect to its investments in securities, the
Company is exposed to the risk of market loss.
    
 
   
     Cash and cash equivalents for the purpose of reporting cash flows include
cash on deposit and debt securities purchased with original maturities of three
months or less.
    
 
  Inventories
 
     Inventories are stated at the lower of cost or market. The LIFO (last-in,
first-out) method is utilized to determine cost for a substantial portion of the
Company's domestic inventories. All other inventories are determined principally
based on the FIFO (first-in, first-out) method.
 
  Property, Plant and Equipment
 
   
     Depreciation is computed principally on the straight-line method based on
the estimated economic lives of the assets. The Company uses an economic life of
10-20 years for land improvements, 40 years for buildings, and 3-20 years for
machinery and equipment, which includes furniture and fixtures. Certain interest
charges are capitalized during the period of construction as part of the cost of
property, plant and equipment.
    
 
  New Accounting Standards
 
     In 1995, the Financial Accounting Standards Board issued SFAS No. 121,
relating to accounting for impairment of long-lived assets, which is required to
be adopted in 1996. The Company does not anticipate that the implementation of
SFAS No. 121 will have a material effect on the Company's results of operations
or financial position.
 
  Foreign Exchange Contracts
 
     The Company enters into forward foreign exchange instruments with
off-balance-sheet risk in order to hedge a portion of both its borrowings
denominated in foreign currency and its firm or anticipated purchase commitments
related to the operations of foreign affiliates. Gains and losses on instruments
used to hedge firm purchase commitments are deferred, and amortization is
included in the measurement of the foreign currency transactions hedged. Gains
and losses on instruments used to hedge anticipated purchases are recognized
within 'Other income, net.'
 
     Forward contract agreements require the Company and the counterparty to
exchange fixed amounts of U.S. dollars for fixed amounts of foreign currency on
specified dates. The market value of such contracts varies with changes in the
market exchange rates. The Company is exposed to credit loss in the event of

nonperformance by
 
                                      F-9
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES--(CONTINUED)
the counterparties to the forward contract agreements. However, the Company does
not anticipate nonperformance by the counterparties. The Company does not
generally require collateral or other security to support these financial
instruments.
 
     As of December 31, 1994 and 1995 and September 29, 1996, the equivalent
dollar fair value of outstanding forward foreign exchange contracts was $110.3,
$183.1 and $175.3 million, respectively, and the amount of deferred gains and
losses on such instruments was immaterial at December 31, 1994 and 1995 and was
a net gain of $2.3 million at September 29, 1996. All forward contracts are in
major currencies with highly liquid markets and mature within one year. The
Company uses quoted market prices obtained from major financial institutions to
determine the market value of its outstanding forward exchange contracts. The
U.S. dollar equivalent fair value of foreign exchange contracts outstanding as
of September 29, 1996 as a hedge of non-local currency loans was $28.6 million,
representing 100% of the Company's foreign currency exposure with respect to
such loans.
 
     The Company continually monitors its risk from the effect of foreign
currency fluctuations on its operations and on the derivative products used to
hedge its risk. The Company utilizes real-time, on-line foreign exchange data
and news as well as evaluation of economic information provided by financial
institutions. Mark-to-market valuations are made on a regular basis. Hedging
strategies are approved by senior management before being implemented.
 
  Foreign Currency Translation
 
     Assets and liabilities of foreign subsidiaries, other than those located in
highly inflationary countries, are translated at year-end exchange rates. The
effects of these translation adjustments are reported in a separate component of
shareholder's equity (deficit), 'Cumulative translation adjustment and other,'
and amounted to $8.5, $14.1 and $10.1 million as of December 31, 1994 and 1995
and September 29, 1996, respectively. Income and expenses are translated at
average exchange rates prevailing during the year. Exchange gains and losses
arising from transactions denominated in a currency other than the functional
currency of the entity involved, and translation adjustments of subsidiaries in
countries with highly inflationary economies, are included in 'Other income,
net.'
 
  Excess of Purchase Price Over the Adjusted Historical Cost of Predecessor
  Company Shares
 
     Shareholder's equity (deficit) reflects a reduction of $72.6 million which
arose from a management-led buyout in March 1989 of the predecessor company to
GAF (the 'Acquisition'), because certain members of the management group owned
shares of the predecessor company's common stock before the Acquisition and own

shares of GAF after the Acquisition. Accordingly, a step-up in asset values to
fair value as required by the purchase method of accounting (which was applied
to the Acquisition) does not apply to their shares.
 
  Excess of Cost Over Net Assets of Businesses Acquired ('Goodwill')
 
     Goodwill, which arose principally from the Acquisition, is amortized on the
straight-line method over a period of approximately 40 years. The Company
believes that the goodwill is recoverable. The primary financial indicator to
assess recoverability of goodwill is operating income before amortization of
goodwill. The assessment is based on an undiscounted analysis.
 
  Debt Issuance Costs
 
     Debt issuance costs are amortized to expense over the life of the related
debt.
 
  Interest Rate Swaps
 
   
     Gains (losses) on interest rate swap agreements ('swaps') are deferred and
amortized as a reduction (increase) of interest expense over the remaining life
of the debt issue with respect to which the swaps were entered.
    
 
                                      F-10
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES--(CONTINUED)
  Research and Development
 
     Research and development costs are charged to continuing operations as
incurred and amounted to $21.2, $20.3, $21.9, $16.2 and $18.4 million for 1993,
1994 and 1995 and the first nine months of 1995 and 1996, respectively.
 
  Investment in Joint Venture
 
     ISP has a 50% ownership in GAF-Huls Chemie GmbH ('GAF-Huls'), a joint
venture which operates a chemical manufacturing plant in Germany, which is
accounted for by the equity method. ISP's equity in the net assets of GAF-Huls
was $33.5, $41.2 and $38.5 million as of December 31, 1994 and 1995 and
September 29, 1996, respectively, and is included in 'Other assets.' Dividends
received by ISP from GAF-Huls totaled $5.4, $4.4, $.3, $.3 and $5.7 million for
1993, 1994 and 1995 and the first nine months of 1995 and 1996, respectively.
 
  Environmental Liability
 
     The Company, together with other companies, is a party to a variety of
proceedings and lawsuits involving environmental matters. The Company estimates
that its liability in respect of such environmental matters for its continuing
operations, and certain other environmental compliance expenses, as of September
29, 1996 is $17.4 million, before reduction for insurance recoveries reflected

on its balance sheet of $6.9 million. The Company's liability is reflected on an
undiscounted basis. See 'Business--Environmental Litigation' for further
discussion with respect to environmental liabilities and estimated insurance
recoveries.
 
NOTE 2. ACQUISITION
 
     In February 1993, ISP acquired the MTM fine chemicals business. Such
acquisition was accounted for under the purchase method of accounting.
Accordingly, the purchase price was allocated to the estimated fair values of
the identifiable net assets acquired, and the excess was recorded as goodwill.
The results of such acquisition are included from the date of acquisition; the
effect was not material to consolidated operations.
 
NOTE 3. PROVISION FOR RESTRUCTURING
 
   
     In the fourth quarter of 1993, ISP recorded a pre-tax provision of $13.8
million, primarily related to its cost reduction program announced in October
1993. The restructuring charge was established to cover costs associated with
severance and related benefits, professional fees, relocations, and
discontinuation of products. Management believes that the cost reduction and
productivity programs have resulted in significantly reduced operating expenses.
The remaining liability as of December 31, 1995 was approximately $4.7 million
and is anticipated to be expended over the next several years.
    
 
                                      F-11

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 4. INCOME TAXES
 
     Income tax (provision) benefit for continuing operations consists of the
following:
 
<TABLE>
<CAPTION>
                                                                                   NINE MONTHS ENDED
                                                                              ----------------------------
                                              YEAR ENDED DECEMBER 31,         OCTOBER 1,     SEPTEMBER 29,
                                          --------------------------------       1995            1996
                                            1993        1994        1995      (UNAUDITED)     (UNAUDITED)
                                          --------    --------    --------    -----------    -------------
                                                                    (THOUSANDS)
<S>                                       <C>         <C>         <C>         <C>            <C>
Federal:
  Current..............................   $(29,555)   $(36,055)   $(48,955)    $ (27,369)      $ (40,473)
  Deferred.............................     15,726      16,051      17,794         4,757          11,353
                                          --------    --------    --------    -----------    -------------
Total Federal..........................    (13,829)    (20,004)    (31,161)      (22,612)        (29,120)
                                          --------    --------    --------    -----------    -------------
Foreign--current.......................     (2,984)     (6,019)     (6,432)       (6,564)         (5,121)
                                          --------    --------    --------    -----------    -------------
State and local:
  Current..............................     (1,268)     (1,152)     (2,149)       (1,173)         (1,393)
  Deferred.............................        761         443       1,015           368             (13)
                                          --------    --------    --------    -----------    -------------
  Total state and local................       (507)       (709)     (1,134)         (805)         (1,406)
                                          --------    --------    --------    -----------    -------------
Income tax provision...................   $(17,320)   $(26,732)   $(38,727)    $ (29,981)      $ (35,647)
                                          --------    --------    --------    -----------    -------------
                                          --------    --------    --------    -----------    -------------
</TABLE>
 
     The differences between the income tax provision computed by applying the
statutory Federal income tax rate to pre-tax income from continuing operations,
and the income tax provision reflected in the Consolidated Statements of Income,
are as follows:
 
<TABLE>
<CAPTION>
                                                                                   NINE MONTHS ENDED
                                                                              ----------------------------
                                              YEAR ENDED DECEMBER 31,         OCTOBER 1,     SEPTEMBER 29,
                                          --------------------------------       1995            1996
                                            1993        1994        1995      (UNAUDITED)     (UNAUDITED)
                                          --------    --------    --------    -----------    -------------
                                                                    (THOUSANDS)
<S>                                       <C>         <C>         <C>         <C>            <C>
Statutory provision....................   $(17,438)   $(25,369)   $(37,136)    $ (28,422)      $ (34,371)

Impact of:
  Foreign operations...................      3,116       1,657       3,633           608           1,590
  Nondeductible goodwill
     amortization......................     (4,849)     (4,690)     (4,628)       (3,473)         (3,465)
  Percentage depletion.................      1,868       1,684       1,824         1,453           1,219
  Other, net...........................        (17)        (14)     (2,420)         (147)           (620)
                                          --------    --------    --------    -----------    -------------
Income tax provision...................   $(17,320)   $(26,732)   $(38,727)    $ (29,981)      $ (35,647)
                                          --------    --------    --------    -----------    -------------
                                          --------    --------    --------    -----------    -------------
</TABLE>
 
                                      F-12
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 4. INCOME TAXES--(CONTINUED)

The components of the net deferred tax liability are as follows:
 
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,        SEPTEMBER 29,
                                                                   --------------------        1996
                                                                     1994        1995       (UNAUDITED)
                                                                   --------    --------    -------------
                                                                                (THOUSANDS)
<S>                                                                <C>         <C>         <C>
Deferred tax liabilities related to:
  Property, plant and equipment.................................   $103,294    $ 90,854      $  90,010
  Other.........................................................      2,582       6,019          4,284
                                                                   --------    --------    -------------
Total deferred tax liabilities..................................    105,876      96,873         94,294
                                                                   --------    --------    -------------
Deferred tax assets related to:
  Deferred income...............................................     (6,694)    (19,912)       (22,351)
  Expenses not yet deducted for tax purposes....................    (24,480)    (14,099)       (20,982)
  Foreign tax credits not yet utilized under the Tax Sharing
     Agreement..................................................     (3,230)     (3,326)        (3,326)
  Other.........................................................     (4,660)    (10,389)        (8,779)
                                                                   --------    --------    -------------
Total deferred tax assets.......................................    (39,064)    (47,726)       (55,438)
                                                                   --------    --------    -------------
Net deferred tax liability......................................     66,812      49,147         38,856
Deferred tax assets reclassified to other current assets........      6,143       6,596          6,596
                                                                   --------    --------    -------------
Noncurrent deferred tax liability...............................   $ 72,955    $ 55,743      $  45,452
                                                                   --------    --------    -------------
                                                                   --------    --------    -------------
</TABLE>
 
     The discussion contained in this Prospectus under the heading 'Tax Sharing
Agreement' is incorporated by reference herein.

 
     In connection with Rhone-Poulenc Surfactants and Specialties, L.P. (the
'Surfactants Partnership'), GCC, an indirect subsidiary of GAF, has recorded a
deferred tax liability in the amount of $131.4 million, which is reflected as a
liability on the consolidated balance sheet of G-I Holdings. Payment of this
liability (subject to reduction to reflect utilization of the tax attributes of
GAF and its subsidiaries) is not expected earlier than 1999 under present
circumstances. In certain circumstances, GCC could be required to satisfy this
liability earlier than 1999. GAF, G-I Holdings and certain subsidiaries of GAF
have agreed to jointly and severally indemnify the Company against such tax
liability. Prior to the Spin Off Transactions, the Company was a member of the
same consolidated federal income tax group as GCC. Subject to such
indemnification, the Company would be severally liable for any tax liability
imposed in connection with the Surfactants Partnership should GAF, G-I Holdings
and such subsidiaries be unable to satisfy such liability. GAF has advised the
Company that, in the event the tax liability becomes payable, GAF believes that
it will have access to sufficient funds to satisfy this liability if so
required.
 
                                      F-13

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 5. SALE OF ACCOUNTS RECEIVABLE
 
     In June 1993, ISP sold its domestic trade accounts receivable, without
recourse, for a maximum of $25 million in cash to be made available to ISP based
on eligible domestic receivables outstanding from time to time. As of November
6, 1996, the agreement under which ISP sells its domestic trade accounts
receivable was extended for one year on substantially the same terms and
conditions, and the maximum purchase amount was increased to $29 million.
 
     The excess of accounts receivable sold over the net proceeds received is
included in 'Accounts receivable, other'. The effective cost to the Company
varies with LIBOR or commercial paper rates and is included in 'Other income,
net'.
 
NOTE 6. INVENTORIES
 
     At December 31, 1994 and 1995 and September 29, 1996, $49.4, $56.2 and
$45.1 million, respectively, of domestic inventories were valued using the LIFO
method. Inventories consist of the following:
 
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                               ----------------------------    SEPTEMBER 29, 1996
                                                                   1994            1995           (UNAUDITED)
                                                               ------------    ------------    ------------------
                                                                                  (THOUSANDS)
<S>                                                            <C>             <C>             <C>
Finished goods..............................................     $   69,748      $   71,431         $ 61,175
Work in process.............................................         21,082          20,540           23,851
Raw materials and supplies..................................         19,900          18,634           17,564
                                                               ------------    ------------    ------------------
Total.......................................................        110,730         110,605          102,590
Less LIFO reserve...........................................         (1,943)         (2,636)          (4,236)
                                                               ------------    ------------    ------------------
Inventories.................................................     $  108,787      $  107,969         $ 98,354
                                                               ------------    ------------    ------------------
                                                               ------------    ------------    ------------------
</TABLE>
 
NOTE 7. PROPERTY, PLANT AND EQUIPMENT
 
     Property, plant and equipment consists of the following:
 
   
<TABLE>
<CAPTION>
                                                                     DECEMBER 31,
                                                             ----------------------------    SEPTEMBER 29, 1996
                                                                 1994            1995           (UNAUDITED)

                                                             ------------    ------------    ------------------
                                                                                (THOUSANDS)
<S>                                                          <C>             <C>             <C>
Land and land improvements................................    $    69,109     $    69,504        $   70,286
Buildings and building equipment..........................         78,808          80,880            81,632
Machinery and equipment...................................        422,795         438,579           471,826
Construction in progress..................................         36,938          46,547            42,922
                                                             ------------    ------------    ------------------
Total.....................................................        607,650         635,510           666,666
Less accumulated depreciation.............................       (130,541)       (159,960)         (184,250)
                                                             ------------    ------------    ------------------
Property, plant and equipment, net........................    $   477,109     $   475,550        $  482,416
                                                             ------------    ------------    ------------------
                                                             ------------    ------------    ------------------
</TABLE>
    
 
                                      F-14
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 8. LONG-TERM DEBT
 
     Long-term debt consists of the following:
 
<TABLE>
<CAPTION>
                                                                       DECEMBER 31,
                                                               ----------------------------    SEPTEMBER 29, 1996
                                                                   1994            1995           (UNAUDITED)
                                                               ------------    ------------    ------------------
                                                                                  (THOUSANDS)
<S>                                                            <C>             <C>             <C>
9% ISP Senior Notes due 1999................................     $  200,000      $  200,000         $200,000
Borrowings under revolving credit facility..................         45,000          40,800               --
Industrial revenue bond.....................................          1,830              --               --
Obligations on mortgaged property...........................         38,125          38,125           38,125
Obligations under capital leases (Note 13)..................          1,332           1,727            1,996
                                                               ------------    ------------    ------------------
Total.......................................................        286,287         280,652          240,121
Less current maturities.....................................           (890)           (398)            (361)
                                                               ------------    ------------    ------------------
Long-term debt less current maturities......................     $  285,397      $  280,254         $239,760
                                                               ------------    ------------    ------------------
                                                               ------------    ------------    ------------------
</TABLE>
 
     In connection with the issuance by ISP of $200 million of 9% Senior Notes
(the '9% Notes') due 1999, ISP entered into swaps with banks in an aggregate
notional principal amount of $200 million. In 1993, ISP terminated the swaps,
resulting in gains of $25.1 million, and entered into new swaps. The gains were
deferred and are being amortized as a reduction of interest expense over the
remaining life of the 9% Notes. As a result of the new swaps, the effective

interest cost to ISP of the 9% Notes varies at a fixed spread over LIBOR. Based
on the fair value of the swaps at December 31, 1994 and 1995 and September 29,
1996, ISP would have incurred losses of $22.1, $2.8 and $6.5 million,
respectively, representing the estimated amount that would be payable by ISP if
the swaps were terminated at such dates. The estimated fair value of the 9%
Notes as of December 31, 1994 and 1995 and September 29, 1996, was $192.6,
$214.6 and $206.7 million, respectively.
 
     The Company may be considered to be at risk, to the extent of the costs of
replacing such swaps at current market rates, in the event of nonperformance by
counterparties. However, since the counterparties are major financial
institutions, the credit ratings of which are continually monitored by the
Company, the risk of such nonperformance is considered by the Company to be
remote.
 
     In October 1994, ISP refinanced its $400 million revolving credit/letter of
credit facility and entered into a four-year $250 million revolving
credit/letter of credit facility and a $150 million renewable one-year revolving
credit facility. In connection with the refinancing of the bank facility, ISP
recorded an extraordinary charge of $1.2 million (after an income tax benefit of
$.7 million), representing the write-off of deferred financing fees related to
the previous bank credit agreement. On July 26, 1996, ISP refinanced its $250
million long-term revolving credit facility and $150 million one-year revolving
credit facility with a $400 million five-year revolving credit facility (the
'ISP Credit Agreement'). Borrowings under the ISP Credit Agreement bear interest
at a floating rate based on the banks' base rate, federal funds rate, Eurodollar
rate or a competitive bid rate (which may be based on LIBOR or money market
rates), at the option of ISP.
 
     As of September 29, 1996, letters of credit aggregating $9.4 million were
outstanding under the ISP Credit Agreement. The ISP Credit Agreement permits ISP
to make loans to affiliates, and to make available letters of credit for the
benefit of affiliates, in an aggregate amount of up to $75 million. As of
September 29, 1996, $2.3 million of letters of credit for the benefit of
affiliates were outstanding.
 
     Borrowings by ISP, including those under the ISP Credit Agreement, are
subject to the application of certain financial covenants contained in such
agreement and in the indentures relating to the Company's 9% Senior Notes due
2003 and 9 3/4% Senior Notes due 2002. As of September 29, 1996, ISP was in
compliance with such covenants, and the application of such covenants would not
have restricted the amounts available for borrowing under the ISP Credit
Agreement. The ISP Credit Agreement and the indenture relating to the 9% Notes
also limit the amount of cash dividends, purchases of treasury stock and other
restricted payments (as defined) by ISP. As
 
                                      F-15
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 8. LONG-TERM DEBT--(CONTINUED)
of September 29, 1996, under the most restrictive of such limitations, ISP could
have paid dividends in the aggregate amount of $79.9 million, of which $66.4

million would have been available to ISP Holdings.
 
     The ISP Credit Agreement and the indenture relating to the 9% Notes contain
additional affirmative and negative covenants, including restrictions on liens,
investments, transactions with affiliates, sale-leaseback transactions, and
mergers and transfers of all or substantially all of the assets of ISP or its
subsidiaries. The ISP Credit Agreement also provides for a default if there is a
change in control (as defined) of ISP.
 
     Neither the ISP Credit Agreement nor the 9% Notes are secured by any assets
of ISP or its subsidiaries. The indenture governing the 9% Notes provides,
subject to certain exceptions, that if ISP issues any debt secured by a lien on
the stock of certain of its subsidiaries or upon any principal property, then
such notes must be equally and ratably secured.
 
     The Company believes that the fair value of its non-public variable rate
indebtedness approximates the book value of such indebtedness because the
interest rates on such indebtedness are at floating short-term rates. The ISP
Credit Agreement also provides for adjustments to the interest rate if there is
a change in the credit rating of ISP. With respect to the Company's publicly
traded debt securities, the Company has obtained estimates of fair values from
an independent source believed to be reliable.
 
     The aggregate maturities of long-term debt for the Company's continuing
operations as of September 29, 1996 for the next five years are as follows:
 
<TABLE>
<CAPTION>
TWELVE MONTHS
ENDED SEPTEMBER 30,                                                                 (THOUSANDS)
- ---------------------------------------------------------------------------------   -----------
<S>                                                                                 <C>
1997.............................................................................    $     361
1998.............................................................................          520
1999.............................................................................      238,408
2000.............................................................................          190
2001.............................................................................          150
</TABLE>
 
     In the above table, for the twelve months ended September 29, 1999,
maturities include the $200 million of 9% Notes and a $38.1 million obligation
on a mortgaged property.
 
     At September 29, 1996, the Company's foreign subsidiaries had total
available short-term lines of credit aggregating $38.1 million, of which $16.3
million were unused. The weighted average interest rate on the Company's
short-term borrowings as of December 31, 1994 and 1995 and September 29, 1996
was 6.1%, 5.8% and 5.2%, respectively.
 
     See Note 16 for information regarding subsequent events relating to
indebtedness of the Company.
 
                                      F-16

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 9. BENEFIT PLANS
 
     Eligible, full-time employees of the Company are covered by various benefit
plans, as described below.
 
  Defined Contribution Plan
 
     The Company provides a defined contribution plan for eligible employees.
The Company contributes up to 7% of participants' compensation (of which, for
ISP employees, up to 4% of participants' compensation, at the participants'
option, is contributed in the form of ISP's common stock at a $.50 per share
discount from the market price on the date of contribution) and also contributes
fixed amounts, ranging from $50 to $750 per year depending on age, to the
accounts of participants who are not covered by a Company-provided
postretirement medical benefit plan. The aggregate contributions by the Company
related to continuing operations were $5.2, $6.1, $6.3, $4.7 and $4.8 million
for 1993, 1994 and 1995 and the first nine months of 1995 and 1996,
respectively.
 
  Defined Benefit Plans
 
     The Company provides a noncontributory defined benefit retirement plan for
certain hourly employees (the 'Hourly Retirement Plan'). Benefits under this
plan are based on stated amounts for each year of service. The Company's funding
policy is consistent with the minimum funding requirements of ERISA.
 
     The Company's net periodic pension cost related to continuing operations
for the Hourly Retirement Plan included the following components:
 
<TABLE>
<CAPTION>
                                                                               YEAR ENDED DECEMBER 31,
                                                                              --------------------------
                                                                               1993      1994      1995
                                                                              ------    ------    ------
                                                                                     (THOUSANDS)
<S>                                                                           <C>       <C>       <C>
Service cost...............................................................   $  395    $  363    $  287
Interest cost..............................................................    1,134     1,253     1,349
Actual income on plan assets...............................................     (985)     (924)     (976)
Net deferral and amortization of unrecognized prior service cost and
  actuarial losses.........................................................      467       343       275
                                                                              ------    ------    ------
Net periodic pension cost..................................................   $1,011    $1,035    $  935
                                                                              ------    ------    ------
                                                                              ------    ------    ------
</TABLE>
 
     Net periodic pension cost related to continuing operations for the Hourly
Retirement Plan was $.7 and $.1 million, respectively, for the first nine months

of 1995 and 1996.
 
                                      F-17
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 9. BENEFIT PLANS--(CONTINUED)

     The following table sets forth the funded status of the Hourly Retirement
Plan for continuing operations:
 
<TABLE>
<CAPTION>
                                                                                        DECEMBER 31,
                                                                                    --------------------
                                                                                      1994        1995
                                                                                    --------    --------
                                                                                        (THOUSANDS)
<S>                                                                                 <C>         <C>
Accumulated benefit obligation:
  Vested.........................................................................   $ 13,460    $ 16,919
  Nonvested......................................................................      2,360       2,273
                                                                                    --------    --------
Total accumulated benefit obligation.............................................   $ 15,820    $ 19,192
                                                                                    --------    --------
                                                                                    --------    --------
Projected benefit obligation.....................................................   $ 15,820    $ 19,192
Fair value of plan assets, primarily listed stocks and U.S. Government
  securities.....................................................................    (10,766)    (15,314)
                                                                                    --------    --------
Projected benefit obligation in excess of plan assets............................      5,054       3,878
Unrecognized prior service cost..................................................     (2,075)     (1,956)
Unrecognized net loss............................................................     (1,180)       (796)
                                                                                    --------    --------
Unfunded accrued pension cost....................................................   $  1,799    $  1,126
                                                                                    --------    --------
                                                                                    --------    --------
</TABLE>
 
     At December 31, 1995, the difference between the 'Projected benefit
obligation in excess of plan assets' and the 'Unfunded accrued pension cost,' in
the amount of $2,752,000, was recorded by the Company as a liability, offset by
an intangible asset in the amount of $1,956,000, a reduction of shareholder's
equity in the amount of $655,000 and a reduction of minority interest in
subsidiary in the amount of $141,000. The foregoing amounts will be amortized to
expense over a period of approximately 15 years, as the Company continues to
fund the benefits under the Hourly Retirement Plan.
 
     In determining the projected benefit obligation, the weighted average
assumed discount rate was 9% and 7.5% for 1994 and 1995, respectively. The
expected long-term rate of return on assets, used in determining net periodic
pension cost, was 9% for 1994 and 1995.
 

     The Company also provides a nonqualified defined benefit retirement plan
for certain key employees. Expense accrued for this plan and charged to
continuing operations was $.8, $1.2, $1.4, $1.1 and $.6 million for 1993, 1994
and 1995 and the first nine months of 1995 and 1996, respectively.
 
  Postretirement Medical and Life Insurance
 
     The Company provides certain medical and life insurance benefits for all
retirees who were formerly hourly employees and for certain retirees who were
formerly salaried employees. Certain hourly employees may become eligible for
benefits if they reach retirement age while working for the Company. The Company
accrues the estimated cost of such retiree benefits during covered employees'
active service periods.
 
     During 1992, the postretirement medical and life insurance plans for
salaried employees were terminated, with certain exceptions for salaried
employees then over age 55 with 10 years of service. Retirees as of December 31,
1992 who were formerly salaried employees maintain life insurance coverage and
receive a Company subsidy of up to $800 per year towards medical coverage, with
certain exceptions. Subsequently, the Company negotiated the termination of
postretirement medical and life insurance plans for certain hourly employees,
with exceptions for hourly employees then over age 50 with 15 or more years of
service.
 
                                      F-18
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 9. BENEFIT PLANS--(CONTINUED)

     The following table shows the components of the accrued postretirement
health care cost obligation for continuing operations as of December 31, 1994
and 1995:
 
<TABLE>
<CAPTION>
                                                                                        DECEMBER 31,
                                                                                     ------------------
                                                                                      1994       1995
                                                                                     -------    -------
                                                                                        (THOUSANDS)
<S>                                                                                  <C>        <C>
Accumulated postretirement benefit obligation:
  Retirees, dependents and beneficiaries eligible for benefits....................   $ 8,038    $ 9,053
  Active employees fully eligible for benefits....................................     1,967      2,042
  Active employees not fully eligible for benefits................................       107        121
                                                                                     -------    -------
Total accumulated postretirement benefit obligation...............................    10,112     11,216
Fair value of plan assets.........................................................        --         --
Unrecognized prior service cost and unrecognized net gain (loss)..................     1,027       (241)
                                                                                     -------    -------
Accrued postretirement benefit obligation.........................................   $11,139    $10,975
                                                                                     -------    -------

                                                                                     -------    -------
</TABLE>
 
     The net periodic postretirement benefit cost for continuing operations
included the following components:
 
<TABLE>
<CAPTION>
                                                                                 YEAR ENDED DECEMBER 31,
                                                                                 -----------------------
                                                                                  1993     1994    1995
                                                                                 ------    ----    -----
                                                                                       (THOUSANDS)
<S>                                                                              <C>       <C>     <C>
Service cost..................................................................   $   75    $ 39    $   3
Interest cost.................................................................    1,012     845      884
Amortization of unrecognized prior service cost and net gain from earlier
  periods.....................................................................       --     (25)    (145)
                                                                                 ------    ----    -----
Net periodic postretirement benefit cost......................................   $1,087    $859    $ 742
                                                                                 ------    ----    -----
                                                                                 ------    ----    -----
</TABLE>
 
     Net periodic postretirement benefit cost for continuing operations was $.6
million for each of the first nine months of 1995 and 1996.
 
     For purposes of calculating the accumulated postretirement benefit
obligation, the following assumptions were made. Retirees as of December 31,
1992 who were formerly salaried employees (with certain exceptions) were assumed
to receive a Company subsidy of $800 per year. With respect to retirees who were
formerly hourly employees, most such retirees are subject to a $5,000 per person
lifetime maximum benefit. Subject to such lifetime maximum, a 14% and 8% annual
rate of increase in the Company's per capita cost of providing postretirement
medical benefits was assumed for 1996 for such retirees under and over age 65,
respectively. To the extent that the lifetime maximum benefits have not been
reached, the foregoing rates were assumed to decrease gradually to 7% and 6%,
respectively, by the year 2003 and remain at that level thereafter. The weighted
average discount rate used in determining the accumulated postretirement benefit
obligation was 9% and 7.5% for 1994 and 1995, respectively.
 
     The health care cost trend rate assumption has an effect on the amounts
reported. To illustrate, increasing the assumed health care cost trend rates by
one percentage point in each year would increase the accumulated postretirement
benefit obligation for continuing operations as of December 31, 1995 by $850,000
and the aggregate of the service and interest cost components of the net
periodic postretirement benefit cost for continuing operations for the year 1995
by $113,000.
 
                                      F-19

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 10. STOCK OPTION PLAN
 
     ISP's 1991 Incentive Plan for Key Employees and Directors, as amended (the
'Plan'), authorizes the grant of options to purchase a maximum of 5,000,000
shares of ISP's common stock. In December 1995, ISP's Board of Directors
approved an amendment to the Plan, which was approved by ISP's stockholders in
1996, to permit the Compensation Committee of the Board of Directors to
determine the exercise price and vesting schedule of options granted under the
Plan. In December 1995, ISP granted options to certain employees to purchase
215,500 shares of ISP's common stock at an exercise price of $5.875 per share.
The difference of $5 per share between the exercise price and the fair market
value of such shares on the date of grant is being recognized as compensation
expense over the vesting period of 2 1/2 years. All other ISP employee options
under the Plan have an exercise price equal to the fair market value of such
shares on the date of grant and become exercisable at a rate of 20% per year on
each of the first five anniversaries of the date of grant. Special vesting rules
apply to options granted to non-employee directors.
 
     In 1993, ISP extended an offer to holders of outstanding stock options with
exercise prices ranging from $7.25 to $14.00 to exchange their existing options
for a lesser number of new options with an exercise price of $6.75.
 
     The following is a summary of transactions pertaining to the Plan:
 
<TABLE>
<CAPTION>
                                                             1993               1994              1995
                                                          ----------     ------------------    ---------
                                                                         (NUMBER OF SHARES)    
<S>                                                       <C>            <C>                   <C>
Outstanding January 1..................................     1,883,649         1,228,964         2,199,716
Granted................................................       825,509         1,321,020         1,355,510
Exercised..............................................            --                --           (28,805)
Exchanged..............................................    (1,177,518)               --                --
Terminated.............................................      (302,676)         (350,268)         (248,982)
                                                          -----------    ------------------    ----------
Outstanding December 31................................     1,228,964         2,199,716         3,277,439
                                                          -----------    ------------------    ----------
                                                          -----------    ------------------    ----------
At December 31:
  Exercisable..........................................       151,118           332,763           710,750
  Available for grant..................................     1,771,036           800,284         1,722,561
Option Price Range Per Share:
  Outstanding..........................................   $      6.75-       $    6.125-       $    5.875-
                                                          $     14.00        $    14.00        $    14.00
  Exercised............................................            --                --        $    6.75-
                                                                   --                --        $     7.25
</TABLE>
 
                                      F-20

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 11. BUSINESS SEGMENT INFORMATION
 
     The following data present business segment information for the Company's
continuing operations.
 
   
<TABLE>
<CAPTION>
                                                                            YEAR ENDED DECEMBER 31,
                                                                        --------------------------------
                                                                          1993        1994        1995
                                                                        --------    --------    --------
                                                                                   (MILLIONS)
<S>                                                                     <C>         <C>         <C>
Net sales:
  Specialty Chemicals................................................   $  434.5    $  482.4    $  556.9
  Mineral Products(1)................................................       81.3        81.1        86.1
  Other..............................................................       32.5        36.5        46.0
                                                                        --------    --------    --------
  Net sales..........................................................   $  548.3    $  600.0    $  689.0
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Operating income(2):
  Specialty Chemicals(3).............................................   $   48.0    $   79.9    $  105.5
  Mineral Products...................................................       16.6        14.6        16.3
  Other..............................................................         .5         4.7         5.3
                                                                        --------    --------    --------
  Operating income...................................................   $   65.1    $   99.2    $  127.1
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Identifiable assets:
  Specialty Chemicals(4).............................................   $  972.6    $  986.3    $  980.0
  Mineral Products...................................................      161.5       161.2       157.9
  Other..............................................................       19.5        20.6        25.6
  General Corporate(5)...............................................       89.7        83.2       149.4
  Net current assets of discontinued operations......................       65.7       106.2       147.5
                                                                        --------    --------    --------
  Identifiable assets................................................   $1,309.0    $1,357.5    $1,460.4
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Capital expenditures and acquisitions:
  Specialty Chemicals................................................   $   54.5    $   22.5    $   31.1
  Mineral Products...................................................        8.3         8.3         6.0
  Other..............................................................         .1          .3         1.8
                                                                        --------    --------    --------
  Total capital expenditures and acquisitions........................   $   62.9    $   31.1    $   38.9
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Depreciation and goodwill amortization:
  Specialty Chemicals................................................   $   33.5    $   36.1    $   38.6

  Mineral Products...................................................        8.7         9.3         9.7
  Other..............................................................         .4          .8          .9
                                                                        --------    --------    --------
  Total depreciation.................................................   $   42.6    $   46.2    $   49.2
                                                                        --------    --------    --------
                                                                        --------    --------    --------
</TABLE>
    
 
- ------------------
(1) Includes sales to BMCA of $43.5, $42.5 and $45.7 million for 1993, 1994 and
    1995, respectively, and sales to USI of $.1 million in 1995.
 
   
(2) On a segment basis, the provision for restructuring (see Note 3) was
    allocated to Specialty Chemicals ($11.8 million), Mineral Products ($.3
    million), and Other ($1.7 million).
    
 
   
(3) Does not include operating income of ISP's 50% ownership of GAF-Huls. ISP's
    equity in the earnings of GAF-Huls is reflected in the Consolidated
    Statements of Income as 'Equity in earnings of joint venture' below
    Operating Income.
    
 
   
(4) Identifiable assets of Specialty Chemicals include ISP's 50% ownership of
    GAF-Huls. See Note 1.
    
 
   
(5) General Corporate assets principally represent the Company's investments in
    trading, available-for-sale and held-to-maturity securities, which are held
    for general corporate purposes and are not allocated to industry segments.
    
 
     ISP manufactures more than 325 specialty chemicals having numerous
applications in consumer and industrial products encompassing such worldwide
markets as pharmaceuticals, hair and skin care, plastics, agricultural, coatings
and adhesives. ISP's mineral products business manufactures ceramic-coated
colored roofing granules which are sold primarily to the North American roofing
industry for use in the manufacture of asphalt roofing shingles. Over 50% of
ISP's sales of mineral products are to BMCA. ISP also manufactures filter
products and advanced materials.
 
                                      F-21

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 12. GEOGRAPHIC INFORMATION
 
     Results set forth below for foreign operations relating to the Company's
continuing operations represent sales and operating income of foreign-based
subsidiaries.
 
   
<TABLE>
<CAPTION>
                                                                            YEAR ENDED DECEMBER 31,
                                                                        --------------------------------
                                                                          1993        1994        1995
                                                                        --------    --------    --------
                                                                                   (MILLIONS)
<S>                                                                     <C>         <C>         <C>
Net sales:
  Domestic operations(1).............................................   $  286.8    $  306.4    $  345.2
  Europe(2)..........................................................      167.7       187.7       218.2
  Asia-Pacific.......................................................       69.3        76.6        92.1
  Other foreign operations...........................................       24.5        29.3        33.5
                                                                        --------    --------    --------
  Net sales..........................................................   $  548.3    $  600.0    $  689.0
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Operating income(3):
  Domestic operations................................................   $   19.3    $   41.3    $   57.9
  Europe.............................................................       30.0        37.5        49.7
  Asia-Pacific.......................................................       12.8        16.2        17.0
  Other foreign operations...........................................        3.0         4.2         2.5
                                                                        --------    --------    --------
  Operating income...................................................       65.1        99.2       127.1
Equity in earnings of joint venture..................................        2.1         2.0         5.4
Interest expense and other, net......................................      (17.4)      (28.7)      (26.4)
                                                                        --------    --------    --------
Income from continuing operations before income taxes and
  extraordinary item.................................................   $   49.8    $   72.5    $  106.1
                                                                        --------    --------    --------
                                                                        --------    --------    --------
Identifiable assets:
  Domestic operations................................................   $1,001.5    $1,001.4    $  984.5
  Europe(4)..........................................................      118.5       128.9       133.1
  Asia-Pacific.......................................................       24.9        28.5        32.2
  Other foreign operations...........................................        8.7         9.3        13.7
  General Corporate(5)...............................................       89.7        83.2       149.4
  Net current assets of discontinued operations......................       65.7       106.2       147.5
                                                                        --------    --------    --------
  Identifiable assets................................................   $1,309.0    $1,357.5    $1,460.4
                                                                        --------    --------    --------
                                                                        --------    --------    --------
</TABLE>

    
 
- ------------------
(1) Net sales--domestic operations excludes sales by the Company's domestic
    subsidiaries to foreign-based subsidiaries of $113.6, $135.1 and $140.9
    million for 1993, 1994 and 1995, respectively.
 
(2) Net sales--Europe excludes sales by the Company's European subsidiaries to
    domestic and other foreign-based subsidiaries of $7.2, $12.8 and $19.9
    million for 1993, 1994 and 1995, respectively.
 
   
(3) On a geographic basis, the provision for restructuring (see Note 3) was
    allocated to domestic operations ($7.6 million), Europe ($5.7 million),
    Asia-Pacific ($.4 million), and other foreign operations ($.1 million).
    
 
(4) Identifiable assets--Europe includes ISP's 50% ownership of GAF-Huls.
 
   
(5) See subnote (5) to Note 11.
    
 
     More than 60% of the Company's international sales in 1995 were in
countries in Western Europe and Japan which are subject to currency exchange
rate fluctuation risks. See Note 1 for a discussion of the Company's policy to
manage these risks. Other countries in which the Company has sales are subject
to additional risks, including high rates of inflation, exchange controls,
government expropriation and general instability.
 
                                      F-22
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 13. COMMITMENTS AND CONTINGENCIES
 
     ISP Holdings is essentially a holding company without independent
businesses or operations and, as such, is dependent upon the cash flow of ISP in
order to satisfy its obligations. Such obligations include $325 million
principal amount of Senior Notes due 2003, and $199.9 million principal amount
of Senior Notes due 2002. See Note 16 to Consolidated Financial Statements for a
discussion of a subsequent event related to the debt obligations of ISP
Holdings. ISP Holdings expects to satisfy such obligations from, among other
things, refinancings of debt, dividends and loans from ISP, as to which there
are restrictions under the ISP Credit Agreement and the Indenture relating to
the ISP 9% Notes (see Note 8), payments pursuant to the Tax Sharing Agreement
between ISP Holdings and ISP and debt financings.
 
     The discussion as to legal matters involving the Company contained in
'Business--Environmental Litigation' is incorporated herein by reference.
 
     GAF and G-I Holdings have established reserves for asbestos bodily injury
claims, as of September 29, 1996, in the amount of $357.8 million (before

estimated present value of recoveries from products liability insurance policies
of $211 million and related deferred tax benefits of $51.4 million). GAF and G-I
Holdings have advised ISP Holdings that certain components of the
asbestos-related liability and the related insurance recoveries have been
reflected on a discounted basis in their financial statements, and that the
aggregate undiscounted liability as of September 29, 1996, before estimated
recoveries from products liability insurance policies, was $398.1 million. GAF
and G-I Holdings have also advised ISP Holdings that they believe that their
reserves adequately reflect their asbestos-related liabilities. GAF's and G-I
Holdings' estimate of liability for asbestos claims is based on a pending
settlement of future asbestos bodily injury claims (the 'Settlement') becoming
effective and on assumptions which relate, among other things, to the number of
new cases filed, the cost of resolving (either by settlement or litigation or
through the mechanism established by the Settlement) pending and future claims,
the realization of related tax benefits, the favorable resolution of pending
litigation against certain insurance companies and the amount of recoveries from
various insurance companies.
 
     Neither ISP, ISP Holdings nor the assets or operations of ISP, which was
operated as a division of a corporate predecessor of GAF prior to July 1986,
have been employed in the manufacture or sale of asbestos products. ISP Holdings
believes that it and ISP should have no legal responsibility for damages in
connection with asbestos-related claims.
 
     Leases for certain property, plant and equipment at two of ISP's mineral
products plants are accounted for as capital leases and are included in
'Property, plant and equipment, net' at December 31, 1994 and 1995 and at
September 29, 1996 in the amount of $1.3, $2.1 and $1.9 million, respectively.
The Company also has operating leases for transportation, production and data
processing equipment and for various buildings. Rental expense on operations
leases for continuing operations was $7, $7.4 and $8.2 million for 1993, 1994
and 1995, respectively. Future minimum lease payments for properties which were
held under long-term noncancelable leases as of December 31, 1995 were as
follows:
 
<TABLE>
<CAPTION>
                                                                            CAPITAL    OPERATING
                                                                            LEASES      LEASES
                                                                            -------    ---------
                                                                                (THOUSANDS)
<S>                                                                         <C>        <C>
1996.....................................................................   $   535     $ 2,758
1997.....................................................................       535       1,839
1998.....................................................................       494       1,055
1999.....................................................................       200         573
2000.....................................................................       146         276
Later years..............................................................       194         247
                                                                            -------    ---------
Total minimum payments...................................................     2,104     $ 6,748
                                                                                       ---------
                                                                                       ---------
Less interest included above.............................................      (377)
                                                                            -------

Present value of net minimum lease payments..............................   $ 1,727
                                                                            -------
                                                                            -------
</TABLE>
 
                                      F-23
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 13. COMMITMENTS AND CONTINGENCIES--(CONTINUED)

     ISP intends to acquire or develop a European manufacturing facility to meet
the needs of ISP's European business. While the originally anticipated
commencement date of the European project has been deferred because ISP has been
able to implement cost efficient capacity expansions at its existing
manufacturing facilities, based upon its current analysis of additional
opportunities for expansion of existing capacity, end-use demand, and other
relevant factors, ISP intends to proceed with the project by the end of 1997.
Costs capitalized to date related to this project are included in 'Construction
in progress.' ISP anticipates utilizing internally generated funds, existing
credit facilities and/or independent financing to fund the cost of the project.
 
     ISP has received conditional site designation from the New Jersey Hazardous
Waste Facilities Siting Commission for the construction of a hazardous waste
treatment, storage and disposal facility at its Linden, New Jersey property,
which designation has been appealed to the Courts by the City of Linden. ISP
estimates that the cost of constructing the facility will be approximately $100
million and, if approved, the facility is anticipated to be in operation three
years after commencement of construction. ISP anticipates utilizing internally
generated cash and/or seeking project or other independent financing therefor.
Accordingly, ISP would not expect such facility to impact materially its
liquidity or capital resources.
 
NOTE 14. DISCONTINUED OPERATIONS
 
     On August 1, 1996, the Company completed the sale of WAXQ, a commercial
radio station operated by GAF Broadcasting Company, Inc. ('GAF Broadcasting'), a
wholly-owned subsidiary of the Company, for a purchase price of $90 million. The
gain on disposal of $43.6 million, after income taxes of $30.6 million, was
recorded in the third quarter of 1996. Accordingly, GAF Broadcasting is reported
as a discontinued operation.
 
     As a result of the spin-off transactions discussed in Note 16, G-I Holdings
and its remaining assets, principally the building materials business,
consisting of BMCA and USI, and the assets and liabilities of GCC, as well as
GAF Broadcasting, are reflected as discontinued operations in the Consolidated
Financial Statements. Summary operating results of such discontinued operations
are as follows:
 
   
<TABLE>
<CAPTION>
                                                                                             NINE MONTHS ENDED

                                                                                        ----------------------------
                                                        YEAR ENDED DECEMBER 31,         OCTOBER 1,     SEPTEMBER 29,
                                                    --------------------------------       1995            1996
                                                      1993        1994        1995      (UNAUDITED)     (UNAUDITED)
                                                    --------    --------    --------    -----------    -------------
                                                                              (THOUSANDS)
<S>                                                 <C>         <C>         <C>         <C>            <C>
Sales............................................   $564,234    $598,666    $695,259     $ 513,967       $ 652,659
                                                    --------    --------    --------    -----------    -------------
                                                    --------    --------    --------    -----------    -------------
Income (loss) before income taxes and
  extraordinary item.............................   $(15,649)   $ (7,430)   $(39,642)    $ (23,826)      $ (25,414)
Income tax (provision) benefit...................      6,234        (435)     17,401         7,988           7,992
                                                    --------    --------    --------    -----------    -------------
Net income (loss)................................   $ (9,415)   $ (7,865)   $(22,241)    $ (15,838)      $ (17,422)
                                                    --------    --------    --------    -----------    -------------
                                                    --------    --------    --------    -----------    -------------
</TABLE>
    
 
                                      F-24
<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 14. DISCONTINUED OPERATIONS--(CONTINUED)
 
   
<TABLE>
<CAPTION>
                                                            DECEMBER 31,          SEPT. 29, 1996
                                                         1994          1995        (UNAUDITED)
                                                      ----------    ----------    --------------
                                                                     (THOUSANDS)
<S>                                                   <C>           <C>           <C>
Assets
  Current assets...................................   $  334,194    $  343,313      $  465,772
  Investment in limited partnership................      450,000       450,000         450,000
  Other noncurrent assets..........................      512,989       581,886         574,885
                                                      ----------    ----------    --------------
     Total assets..................................   $1,297,183    $1,375,199      $1,490,657
                                                      ----------    ----------    --------------
                                                      ----------    ----------    --------------
Liabilities
  Current liabilities(1)...........................   $  227,957    $  195,862      $  210,793
  Long-term debt(2)................................    1,136,810     1,270,093       1,322,778
  Other noncurrent liabilities(1)..................      417,771       440,598         472,378
                                                      ----------    ----------    --------------
     Total liabilities.............................   $1,782,538    $1,906,553      $2,005,949
                                                      ----------    ----------    --------------
                                                      ----------    ----------    --------------
</TABLE>
    
 

- ------------------
   
(1) Current liabilities include a reserve for asbestos claims of $137.7, $84.4
    and $86.5 million, respectively, as of December 31, 1994 and 1995 and
    September 29, 1996. Other noncurrent liabilities include a reserve for
    asbestos claims of $320.6, $297.4 and $271.2 million, respectively, as of
    December 31, 1994 and 1995 and September 29, 1996.
    
 
   
(2) See Note 16 for a subsequent event related to the long-term debt of G-I
    Holdings.
    
 
NOTE 15. RELATED PARTY TRANSACTIONS
 
     BMCA, an affiliate of the Company, purchases colored roofing granule
requirements from ISP under a requirements contract which was renewed for 1996
and is subject to annual renewal unless terminated by ISP or BMCA. Such
purchases totaled $43.5, $42.5, $45.7, $35.9 and $35.7 million for 1993, 1994,
1995 and the first nine months of 1995 and 1996, respectively. In addition, in
December 1995, USI commenced purchasing substantially all of its requirements
for colored roofing granules from ISP (except for the requirements of its
Stockton, California and Corvallis, Oregon plants) pursuant to a requirements
contract which expires December 31, 1997. Such purchases totaled $.1 million for
1995 and $3.3 million for the first nine months of 1996. The receivable from
BMCA for sales of mineral products was $2.6, $2.7 and $5.9 million at December
31, 1994 and 1995 and September 29, 1996, respectively, and the receivable from
USI for sales of mineral products was $.1 and $2.1 million at December 31, 1995
and September 29, 1996, respectively.
 
   
     Pursuant to a Management Agreement, which expires at the end of 1996, ISP
provides certain general management, administrative, and facilities services to
certain of its affiliates. Charges by ISP for providing such services aggregated
$4.8, $4.4, $4.5, $3.4 and $3.7 million for 1993, 1994 and 1995, and the first
nine months of 1995 and 1996 respectively, and are reflected as reductions of
'Selling, general and administrative' expense, offset by a charge to
discontinued operations. The basis for such charges is an allocation of the
actual costs ISP incurs to provide management services, including, but not
limited to, executive, legal, tax, treasury and accounting services, and the
costs to ISP of providing and maintaining facilities services at the corporate
headquarters, which is owned by a subsidiary of ISP. Such charges will continue
after the Spin Off Transactions are consummated (see Note 16), and accordingly,
ISP Holdings' income from continuing operations will not be affected. In
addition to the management services charge, BMCA paid approximately $.7 million
to ISP in each of 1993, 1994 and 1995, and $.5 million for the first nine months
of 1995 and 1996, primarily for telecommunications and information services, and
G-I Holdings and BMCA paid an aggregate of approximately $.3 and $.2 million in
1994 and 1995, respectively, to ISP for certain legal services, which in each
case were not encompassed within the Management Agreement.
    
 
                                      F-25

<PAGE>
                               ISP HOLDINGS INC.
            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(CONTINUED)
 
NOTE 15. RELATED PARTY TRANSACTIONS--(CONTINUED)

   
     ISP and its subsidiaries also borrow from G-I Holdings and its subsidiaries
at the same rates available to ISP under the ISP Credit Agreement. Such
borrowings outstanding at December 31, 1994 and 1995 and September 29, 1996
comprised $41.3, $50.6 and $17.8 million, respectively, classified as current,
and $91.7, $67.2 and $81.0 million, respectively, classified as long term
pursuant to a note agreement expiring in July 2001.
    
 
     Certain executive officers of ISP were granted stock appreciation rights in
1993 and 1994 relating to GAF's common stock. Compensation expense in connection
with such stock appreciation rights is reflected in G-I Holdings' operating
expense and was immaterial for 1995, 1994 and 1993.
 
NOTE 16. SUBSEQUENT EVENT (UNAUDITED)
 
   
     On October 18, 1996, ISP Holdings concluded a cash tender offer and consent
solicitation for G-I Holdings' outstanding Senior Discount Notes. Pursuant to
the tender offer, $428.5 million aggregate principal amount of G-I Holdings'
Senior Discount Notes were purchased by ISP Holdings and $133 million aggregate
principal amount of such Discount Notes were subsequently repurchased by G-I
Holdings (utilizing cash on hand and the repayment of monies owed to G-I
Holdings by ISP) from ISP Holdings. ISP Holdings also concluded an offer to
exchange its new Senior Notes due February 15, 2002 for G-I Holdings' Senior
Notes. Pursuant to the exchange offer, $199.9 million of the G-I Holdings'
Senior Notes were acquired by ISP Holdings.
    
 
   
     On January 1, 1997, GAF effected a series of transactions involving its
subsidiaries that resulted in the capital stock of ISP Holdings (whose principal
asset is now approximately 83.5% of the issued and outstanding common stock of
ISP) being distributed to the stockholders of GAF. As a result of such
distribution, ISP Holdings and ISP are no longer direct or indirect subsidiaries
of GAF, and the other assets of GAF, principally the building materials
business, consisting of BMCA and USI, remain assets of G-I Holdings. G-I
Holdings remained a wholly-owned subsidiary of ISP Holdings until such
transactions were consummated. Upon consummation of such transactions, all G-I
Holdings' Senior Discount Notes and G-I Holdings' Senior Notes then held by ISP
Holdings were contributed to G-I Holdings and cancelled.
    
 
                                      F-26

<PAGE>
                               ISP HOLDINGS INC.
                         SUPPLEMENTARY DATA (UNAUDITED)
                      QUARTERLY FINANCIAL DATA (UNAUDITED)
 
<TABLE>
<CAPTION>
                                                          1994 BY QUARTER                      1995 BY QUARTER
                                                 ----------------------------------   ---------------------------------
                                                 FIRST    SECOND    THIRD    FOURTH   FIRST    SECOND   THIRD    FOURTH
                                                 ------   ------   -------   ------   ------   ------   ------   ------
                                                                               (MILLIONS)
<S>                                              <C>      <C>      <C>       <C>      <C>      <C>      <C>      <C>
Net sales.....................................   $147.5   $155.8   $ 149.2   $147.5   $179.9   $182.6   $167.8   $158.7
Cost of products sold.........................     90.3     93.2      92.5     91.7    113.2    109.2     99.9     92.4
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Gross profit..................................   $ 57.2   $ 62.6   $  56.7   $ 55.8   $ 66.7   $ 73.4   $ 67.9   $ 66.3
                                                 ------   ------   -------   ------   ------   ------   ------   ------
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Operating income..............................   $ 24.8   $ 29.7   $  22.8   $ 21.9   $ 31.2   $ 36.2   $ 31.8   $ 27.9
                                                 ------   ------   -------   ------   ------   ------   ------   ------
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Income from continuing operations before
  income taxes and extraordinary item.........   $ 16.5   $ 23.6   $  22.7   $  9.7   $ 24.1   $ 29.6   $ 27.5   $ 24.9
Income taxes..................................     (6.2)    (8.8)     (8.4)    (3.4)    (9.0)   (11.1)    (9.9)    (8.7)
Minority interest in income of subsidiary.....     (2.0)    (2.9)     (2.5)    (1.2)    (2.9)    (3.4)    (3.2)    (2.8)
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Income from continuing operations before
  extraordinary item..........................      8.3     11.9      11.8      5.1     12.2     15.1     14.4     13.4
Income (loss) from discontinued operations,
  net of income taxes.........................     (6.6)    11.3      (2.6)   (10.0)    (9.4)    (3.8)    (2.6)    (6.5)
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Income (loss) before extraordinary item.......      1.7     23.2       9.2     (4.9)     2.8     11.3     11.8      6.9
Extraordinary item, net of related income tax
  benefit.....................................       --       --      (1.2)      --       --       --       --       --
                                                 ------   ------   -------   ------   ------   ------   ------   ------
Net income (loss).............................   $  1.7   $ 23.2   $   8.0   $ (4.9)  $  2.8   $ 11.3   $ 11.8   $  6.9
                                                 ------   ------   -------   ------   ------   ------   ------   ------
                                                 ------   ------   -------   ------   ------   ------   ------   ------
</TABLE>
 
                                      F-27

<PAGE>

=============================================================================== 
     NO DEALER, SALESPERSON OR OTHER INDIVIDUAL HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS NOT CONTAINED IN THIS PROSPECTUS IN
CONNECTION WITH THE EXCHANGE OFFERS COVERED BY THIS PROSPECTUS. IF GIVEN OR
MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED BY ISP HOLDINGS. THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO
SELL, OR A SOLICITATION OF AN OFFER TO BUY, THE NOTES IN ANY JURISDICTION WHERE,
OR TO ANY PERSON TO WHOM, IT IS UNLAWFUL TO MAKE SUCH OFFER OR SOLICITATION.
NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER
ANY CIRCUMSTANCES, CREATE AN IMPLICATION THAT THERE HAS NOT BEEN ANY CHANGE IN
THE FACTS SET FORTH IN THIS PROSPECTUS OR IN THE AFFAIRS OF THE COMPANY SINCE
THE DATE HEREOF.
 
                            ------------------------
 
                               TABLE OF CONTENTS
 
   
<TABLE>
<CAPTION>
                                                  PAGE
                                                  ----
<S>                                               <C>
Summary........................................     1
Risk Factors...................................    17
Capitalization.................................    22
Selected Financial Data........................    23
Pro Forma Consolidated Financial Statements....    25
Management's Discussion and Analysis of
  Financial Condition and Results of
  Operations...................................    31
The Spin Off Transactions......................    37
The ISP Holdings Transactions..................    38
Business.......................................    39
Management.....................................    48
Executive Compensation.........................    51
Security Ownership of Certain Beneficial Owners
  and Management...............................    55
Tax Sharing Agreement..........................    56
Certain Relationships..........................    57
The Exchange Offers............................    58
Description of the New Notes...................    64
Federal Income Tax
  Considerations...............................    87
Plan of Distribution...........................    89
Legal Matters..................................    89
Experts........................................    90
Available Information..........................    90
Index to Financial Statements..................   F-1
</TABLE>
    
 

                                  $325,000,000
                            SERIES B 9% SENIOR NOTES
                                    DUE 2003
 
                                      AND
 
                                  $199,871,000
                          SERIES B 9 3/4% SENIOR NOTES
                                    DUE 2002
 
                               ISP HOLDINGS INC.
 
                            ------------------------
                                   PROSPECTUS
                            ------------------------
   
                                         , 1997
    

=============================================================================== 

<PAGE>
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 20. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
   
     ISP Holdings Inc. is a Delaware corporation. Subsection (b)(7) of Section
102 of the Delaware General Corporation Law (the 'DGCL') enables a corporation
in its original certificate of incorporation or an amendment thereto to
eliminate or limit the personal liability of a director to the corporation or
its stockholders for monetary damages for violations of the director's fiduciary
duty, except (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii)
pursuant to Section 174 of the DGCL (providing for liability of directors for
unlawful payment of dividends or unlawful stock purchases or redemptions) or
(iv) for any transaction from which a director derived an improper personal
benefit. Article Seventh of ISP Holdings' Certificate of Incorporation has
eliminated the personal liability of directors to the fullest extent permitted
by Subsection (b)(7) of Section 102 of the DGCL.
    
 
     Subsection (a) of Section 145 of the DGCL empowers a corporation to
indemnify any director or officer, or former director or officer, who was or is
a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the corporation) by
reason of the fact that such person is or was a director or officer of the
corporation, or is or was serving at the request of the corporation as a
director, officer, employee or agent of another corporation, partnership, joint
venture, trust or other enterprise, against expenses (including attorneys'
fees), judgments, fines and amounts paid in settlement actually and reasonably
incurred in connection with such action, suit or proceeding provided that such
director or officer acted in good faith in a manner reasonably believed to be
in, or not opposed to, the best interests of the corporation, and, with respect
to any criminal action or proceeding, provided further that such director or
officer has no reasonable cause to believe his conduct was unlawful.
 
     Subsection (b) of Section 145 empowers a corporation to indemnify any
director or officer, or former director or officer, who was or is a party or is
threatened to be made a party to any threatened, pending or completed action or
suit by or in the right of the corporation to procure a judgment in its favor by
reason of the fact that such person acted in any of the capacities set forth
above, against expenses (including attorneys' fees) actually and reasonably
incurred in connection with the defense or settlement of such action or suit
provided that such director or officer acted in good faith and in a manner he
reasonably believed to be in, or not opposed to, the best interests of the
corporation, except that no indemnification may be made in respect of any claim,
issue or matter as to which such director or officer shall have been adjudged to
be liable to the corporation unless and only to the extent that the Court of
Chancery or the court in which such action or suit was brought shall determine
upon application that, despite the adjudication of liability but in view of all

of the circumstances of the case, such director or officer is fairly and
reasonably entitled to indemnity for such expenses which the Court of Chancery
or such other court shall deem proper.
 
     Section 145 further provides that to the extent a director or officer of a
corporation has been successful in the defense of any action, suit or proceeding
referred to in subsections (a) and (b) or in the defense of any claim, issue or
matter therein, he shall be indemnified against expenses (including attorneys'
fees) actually and reasonably incurred by him in connection therewith; that
indemnification and advancement of expenses provided for, by, or granted
pursuant to, Section 145 shall not be deemed exclusive of any other rights to
which the indemnified party may be entitled; and empowers the corporation to
purchase and maintain insurance on behalf of any person who is or was a director
or officer of the corporation, or is or was serving at the request of the
corporation as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise against any liability
asserted against him or incurred by him in any such capacity, or arising out of
his status as such, whether or not the corporation would have the power to
indemnify him against such liabilities under Section 145.
 
     Article VIII of the Company's By-Laws states that the corporation shall
indemnify, any person who was or is a party or is threatened to be made a party
to any threatened, pending, or completed action or suit by reason of the fact
that he is or was a director, officer or employee of the corporation, or is or
was serving at the request of
 
                                      II-1
<PAGE>
ITEM 20. INDEMNIFICATION OF DIRECTORS AND OFFICERS.--(CONTINUED)

the corporation as a director, officer or employee of another corporation,
partnership, joint venture, trust or other enterprise against judgments, fines
and amounts paid in settlement actually incurred by him in connection with such
action or suit if he acted in good faith and in a manner he reasonably believed
to be in or not opposed to the best interests of the corporation.
 
ITEM 21. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.
 
     (a) Exhibits
 
   
<TABLE>
     <S>                    <C>
      *3.1                  --   Certificate of Incorporation of ISP Holdings.
      *3.2                  --   By-laws of ISP Holdings.
      *4.1                  --   9% Note Indenture, dated as of October 18, 1996, between ISP Holdings and The Bank of New York,
                                 as trustee.
      *4.2                  --   9 3/4% Note Indenture, dated as of October 18, 1996, between ISP Holdings and The Bank of New
                                 York, as trustee (including the Registration Rights Agreement of ISP Holdings attached thereto).
      *4.3                  --   Form of Notes (included in Exhibits 4.1 and 4.2).
      *4.4                  --   Registration Rights Agreement, dated October 18, 1996, between ISP Holdings and Bear, Stearns &
                                 Co. Inc.
     **5                    --   Opinion of Weil, Gotshal & Manges LLP re: legality.
     **8                    --   Opinion of Weil, Gotshal & Manges LLP re: tax matters.

      10.1                  --   Management Agreement, dated as of March 3, 1992 ('Management Agreement'), among GAF, G-I
                                 Holdings, G Industries, ISP, GAF Building Materials Corporation and GAF Broadcasting
                                 (incorporated by reference to Exhibit 10.9 to the Registration Statement on Form S-4 of G-I
                                 Holdings (Registration No. 33-72220)).
      10.2                  --   Amendment No. 1, dated as of January 1, 1994, to the Management Agreement (incorporated by
                                 reference to Exhibit 10.10 to G-I Holdings' Form 10-K for the year ended December 31, 1993).
      10.3                  --   Amendment No. 2, dated as of May 31, 1994, to the Management Agreement (incorporated by
                                 reference to Exhibit 10.1 to G-I Holdings' Form 10-Q for the quarter ended July 3, 1994).
      10.4                  --   Amendment No. 3, dated as of December 31, 1994, to the Management Agreement (incorporated by
                                 reference to Exhibit 10.4 to ISP's Form 10-K for the year ended December 31, 1994).
      10.5                  --   Amendment No. 4, dated as of December 31, 1995, to the Management Agreement (incorporated by
                                 reference to Exhibit 10.6 to the Registration Statement on Form S-4 of G-I Holdings
                                 (Registration No. 333-2436)).
     *10.6                  --   Amendment No. 5, dated as of October 18, 1996 to the Management Agreement.
     *10.7                  --   Indemnification Agreement, dated as of October 18, 1996 among GAF, G-I Holdings, ISP Holdings, G
                                 Industries and GCC.
    **10.8                  --   Tax Sharing Agreement, dated as of January 1, 1997, among ISP Holdings, ISP and certain
                                 subsidiaries of ISP.
      10.9                  --   Non-Qualified Retirement Plan Letter Agreement (incorporated by reference to Exhibit 10.11 to
                                 ISP's Registration Statement on Form S-1, Registration No. 33-40337).
      10.10                 --   ISP Amended and Restated 1991 Incentive Plan for Key Employees (incorporated by reference to
                                   Exhibit 99 to ISP's Registration Statement on Form S-8, No. 33-92518).
      10.11                 --   Agreement, dated July 30, 1993, between ISP and Carl R. Eckardt (incorporated by reference to
                                 Exhibit 10.16 to the Discount Notes Registration Statement).
      10.12                 --   Stock Appreciation Rights Agreement, dated January 20, 1994, between GAF and James P. Rogers
                                 (incorporated by reference to Exhibit 10.20 to G-I Holdings' Form 10-K for the year ended
                                 December 31, 1993).
</TABLE>
    
 
                                      II-2
<PAGE>
ITEM 21. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.--(CONTINUED)
   
<TABLE>
      <S>                    <C>
      10.13                 --   Indenture, dated as of March 1, 1992, relating to ISP's 9% Senior Notes due March 1, 1999
                                 (incorporated by reference to Exhibit 4 to ISP's Registration Statement on Form S-1,
                                 Registration No. 33-44862).
     *10.14                 --   Letter Agreement dated October 15, 1996 between GAF and Dr. Peter Heinze.
     *12                    --   Computation of Ratio of Earnings to Fixed Charges.
     *21                    --   Subsidiaries of ISP Holdings.
    **23.1                  --   Consent of Arthur Andersen LLP.
    **23.2                  --   Consent of Weil, Gotshal & Manges LLP (included in Exhibits 5 and 8).
     *24                    --   Power of Attorney.
     *25.1                  --   Form T-1 Statement of Eligibility under the Trust Indenture Act of 1939, as amended, of The Bank
                                 of New York, as Trustee under the 9% Note Indenture.
     *25.2                  --   Form T-1 Statement of Eligibility under the Trust Indenture Act of 1939, as amended, of The Bank
                                 of New York, as Trustee under the 9 3/4% Note Indenture.
     *27.1                  --   Financial Data Schedule for fiscal year 1995, which is submitted electronically to the
                                 Securities and Exchange Commission for information only.
    **27.2                  --   Financial Data Schedule for the first nine months of fiscal year 1996, which is submitted
                                 electronically to the Securities and Exchange Commission for information only.
    **99.1                  --   Form of 9% Note Letter of Transmittal.

    **99.2                  --   Form of 9 3/4% Note Letter of Transmittal.
    **99.3                  --   Form of 9% Notice of Guaranteed Delivery.
    **99.4                  --   Form of 9 3/4% Notice of Guaranteed Delivery.
    **99.5                  --   Form of Exchange Agent Agreement between The Bank of New York and ISP Holdings.
</TABLE>
    
 
- ------------------
   
 * Previously filed.
    
   
** Filed herewith.
    
 
     (b) Schedules
 
<TABLE>
<S>                                                                                       <C>
Consolidated Financial Statement Schedules:
  Report of Independent Public Accountants.............................................   S-1
  Schedule II--Valuation and Qualifying Accounts.......................................   S-2
</TABLE>
 
ITEM 22. UNDERTAKINGS.
 
     (a) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.
 
     (b) The undersigned Registrant hereby undertakes to respond to requests for
information that is incorporated by reference into the Prospectus pursuant to
Items 4, 10(b), 11 or 13 of this form, within one business day of receipt of
such request, and to send the incorporated documents by first class mail or
other equally prompt means. This includes information contained in documents
filed subsequent to the effective date of the Registration Statement through the
date of responding to the request.
 
     (c) The undersigned Registrant hereby undertakes to supply by means of a
post-effective amendment all information concerning a transaction, and the
company being acquired involved therein, that was not the subject of and
included in the Registration Statement when it became effective.

 
                                      II-3

<PAGE>
                                   SIGNATURES
 
   
     Pursuant to the requirements of the Securities Act of 1933, the registrant
has duly caused this Amendment to the Registration Statement to be signed on its
behalf by the undersigned thereunto duly authorized, in the City of Wayne, State
of New Jersey, on the 13th day of February 1997.
    
 
                                          ISP HOLDINGS INC.
 
   
                                          By: /s/ JAMES P. ROGERS
                                             --------------------------------
                                             Name:  James P. Rogers
                                             Title:  Executive Vice President
                                                    and Chief Financial Officer
    
 
   
     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
    
 
   
<TABLE>
<CAPTION>
                SIGNATURE                                      TITLE                             DATE
- ------------------------------------------  -------------------------------------------   -------------------
 
<S>                                        <C>                                            <C>
                    *                       Chairman, Chief Executive Officer and         February 13, 1997
- ------------------------------------------  Director (Principal Executive Officer)
             Samuel J. Heyman
 
           /s/ JAMES P. ROGERS              Executive Vice President and Chief            February 13, 1997
- ------------------------------------------  Financial Officer (Principal Financial
               James P. Rogers              Officer)
 
                    *                       Vice President and Controller (Principal      February 13, 1997
- ------------------------------------------  Accounting Officer)
            Jonathan H. Stern

 
*By James P. Rogers
    Attorney-in-Fact
</TABLE>
    
 
                                      II-4

<PAGE>
                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To ISP Holdings Inc.:
 
     We have audited in accordance with generally accepted auditing standards,
the consolidated financial statements of ISP Holdings Inc. and subsidiaries
included in this registration statement and have issued our report thereon dated
August 7, 1996. Our audit was made for the purpose of forming an opinion on the
basic financial statements taken as a whole. The schedule listed in item 21(b)
is the responsibility of the Company's management and is presented for purposes
of complying with the Securities and Exchange Commission's rules and is not part
of the basic financial statements. This schedule has been subjected to the
auditing procedures applied in the audit of the basic financial statements and,
in our opinion, fairly states in all material respects the financial data
required to be set forth therein in relation to the basic financial statements
taken as a whole.
 
                                          ARTHUR ANDERSEN LLP
 
Roseland, New Jersey
August 7, 1996
 
                                      S-1

<PAGE>
                                                                     SCHEDULE II
 
                               ISP HOLDINGS INC.
                       VALUATION AND QUALIFYING ACCOUNTS
 
                          YEAR ENDED DECEMBER 31, 1993
                                  (THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                  BALANCE      CHARGED TO                    BALANCE
                                                                 JANUARY 1,    COSTS AND                   DECEMBER 31,
DESCRIPTION                                                         1993        EXPENSES     DEDUCTIONS        1993
- --------------------------------------------------------------   ----------    ----------    ----------    ------------
<S>                                                              <C>           <C>           <C>           <C>
Valuation and Qualifying Accounts Deducted from Assets to
  Which They Apply:
     Allowance for doubtful accounts..........................     $2,105        $  392        $  184(a)     $  2,313
     Reserve for inventory market valuation...................      5,872         5,142         2,023           8,991
</TABLE>
 
                          YEAR ENDED DECEMBER 31, 1994
                                  (THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                  BALANCE      CHARGED TO                    BALANCE
                                                                 JANUARY 1,    COSTS AND                   DECEMBER 31,
DESCRIPTION                                                         1994        EXPENSES     DEDUCTIONS        1994
- --------------------------------------------------------------   ----------    ----------    ----------    ------------
<S>                                                              <C>           <C>           <C>           <C>
Valuation and Qualifying Accounts Deducted from Assets to
  Which They Apply:
     Allowance for doubtful accounts..........................     $2,313        $  325        $  346(a)     $  2,292
     Reserve for inventory market valuation...................      8,991         7,052         6,412           9,631
</TABLE>
 
                          YEAR ENDED DECEMBER 31, 1995
                                  (THOUSANDS)
 
<TABLE>
<CAPTION>
                                                                  BALANCE      CHARGED TO                    BALANCE
                                                                 JANUARY 1,    COSTS AND                   DECEMBER 31,
DESCRIPTION                                                         1995        EXPENSES     DEDUCTIONS        1995
- --------------------------------------------------------------   ----------    ----------    ----------    ------------
<S>                                                              <C>           <C>           <C>           <C>
Valuation and Qualifying Accounts Deducted from Assets to
  Which They Apply:
     Allowance for doubtful accounts..........................     $2,292        $  681        $   94(a)     $  2,879
     Reserve for inventory market valuation...................      9,631         8,861         4,514          13,978
</TABLE>
 

- ------------------
Note:
(a) Represents write-offs of uncollectible accounts net of recoveries.
 
                                      S-2

<PAGE>
                                 EXHIBIT INDEX
 
   
<TABLE>
<CAPTION>
EXHIBIT
NUMBER    DESCRIPTION
- -------   -----------------------------------------------------------------------------------------------
  <S>      <C>
  *3.1     --   Certificate of Incorporation of ISP Holdings.
  *3.2     --   By-laws of ISP Holdings.
  *4.1     --   9% Note Indenture, dated as of October 18, 1996, between ISP Holdings and The Bank of New
                York, as trustee.
  *4.2     --   9 3/4% Note Indenture, dated as of October 18, 1996, between ISP Holdings and The Bank of
                New York, as trustee (including the Registration Rights Agreement of ISP Holdings
                attached thereto).
  *4.3     --   Form of Notes (included in Exhibits 4.1 and 4.2).
  *4.4     --   Registration Rights Agreement, dated October 18, 1996, between ISP Holdings and Bear,
                Stearns & Co. Inc.
 **5       --   Opinion of Weil, Gotshal & Manges LLP re: legality.
 **8       --   Opinion of Weil, Gotshal & Manges LLP re: tax matters.
  10.1     --   Management Agreement, dated as of March 3, 1992 ('Management Agreement'), among GAF, G-I
                Holdings, G Industries, ISP, GAF Building Materials Corporation and GAF Broadcasting
                (incorporated by reference to Exhibit 10.9 to the Registration Statement on Form S-4 of
                G-I Holdings (Registration No. 33-72220)).
  10.2     --   Amendment No. 1, dated as of January 1, 1994, to the Management Agreement (incorporated
                by reference to Exhibit 10.10 to G-I Holdings' Form 10-K for the year ended December 31,
                1993).
  10.3     --   Amendment No. 2, dated as of May 31, 1994, to the Management Agreement (incorporated by
                reference to Exhibit 10.1 to G-I Holdings' Form 10-Q for the quarter ended July 3, 1994).
  10.4     --   Amendment No. 3, dated as of December 31, 1994, to the Management Agreement (incorporated
                by reference to Exhibit 10.4 to ISP's Form 10-K for the year ended December 31, 1994).
  10.5     --   Amendment No. 4, dated as of December 31, 1995, to the Management Agreement (incorporated
                by reference to Exhibit 10.6 to the Registration Statement on Form S-4 of G-I Holdings
                (Registration No. 333-2436)).
 *10.6     --   Amendment No. 5, dated as of October 18, 1996 to the Management Agreement.
 *10.7     --   Indemnification Agreement, dated as of October 18, 1996 among GAF, G-I Holdings, ISP
                Holdings, G Industries and GCC.
**10.8     --   Tax Sharing Agreement, dated as of January 1, 1997, among ISP Holdings, ISP and certain
                subsidiaries of ISP.
  10.9     --   Non-Qualified Retirement Plan Letter Agreement (incorporated by reference to Exhibit
                10.11 to ISP's Registration Statement on Form S-1, Registration No. 33-40337).
  10.10    --   ISP Amended and Restated 1991 Incentive Plan for Key Employees (incorporated by reference
                to Exhibit 99 to ISP's Registration Statement on Form S-8, No. 33-92518).
  10.11    --   Agreement, dated July 30, 1993, between ISP and Carl R. Eckardt (incorporated by
                reference to Exhibit 10.16 to the Discount Notes Registration Statement).
  10.12    --   Stock Appreciation Rights Agreement, dated January 20, 1994, between GAF and James P.
                Rogers (incorporated by reference to Exhibit 10.20 to G-I Holdings' Form 10-K for the
                year ended December 31, 1993).
  10.13    --   Indenture, dated as of March 1, 1992, relating to ISP's 9% Senior Notes due March 1, 1999
                (incorporated by reference to Exhibit 4 to ISP's Registration Statement on Form S-1,
                Registration No. 33-44862).
 *10.14    --   Letter Agreement dated October 15, 1996 between GAF and Dr. Peter Heinze.

 *12       --   Computation of Ratio of Earnings to Fixed Charges.
</TABLE>
    
<PAGE>
   
<TABLE>
<CAPTION>
EXHIBIT
NUMBER    DESCRIPTION
- -------   -----------------------------------------------------------------------------------------------
<S>       <C>
 *21       --   Subsidiaries of ISP Holdings.
**23.1     --   Consent of Arthur Andersen LLP.
**23.2     --   Consent of Weil, Gotshal & Manges LLP (included in Exhibits 5 and 8).
 *24       --   Power of Attorney (included on signature pages to Registration Statement).
 *25.1     --   Form T-1 Statement of Eligibility under the Trust Indenture Act of 1939, as amended, of
                The Bank of New York, as Trustee under the 9% Note Indenture (bound separately).
 *25.2     --   Form T-1 Statement of Eligibility under the Trust Indenture Act of 1939, as amended, of
                The Bank of New York, as Trustee under the 9 3/4% Note Indenture (bound separately).
 *27.1     --   Financial Data Schedule for fiscal year 1995, which is submitted electronically to the
                Securities and Exchange Commission for information only.
**27.2     --   Financial Data Schedule for the first nine months of fiscal year 1996, which is submitted
                electronically to the Securities and Exchange Commission for information only.
**99.1     --   Form of 9% Note Letter of Transmittal.
**99.2     --   Form of 9 3/4% Note Letter of Transmittal.
**99.3     --   Form of 9% Notice of Guaranteed Delivery.
**99.4     --   Form of 9 3/4% Notice of Guaranteed Delivery.
**99.5     --   Form of Exchange Agent Agreement between The Bank of New York and ISP Holdings.
</TABLE>
    
 
- ------------------
   
 * Previously filed.
    
   
** Filed herewith.
    



<PAGE>


                   [Letterhead of Weil, Gotshal & Manges LLP]


                                             February 12, 1997

ISP Holdings Inc.
818 Washington Street
Wilmington, Delaware  19801

Gentlemen:

                  We have acted as counsel to ISP Holdings Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission of the Company's Registration Statement
on Form S-4, File No. 333-17827 (as amended, the "Registration Statement"),
under the Securities Act of 1933, as amended, relating to $325,000,000 principal
amount of the Company's Series B 9% Senior Notes due 2003 (the "9% Notes") and
$199,871,000 principal amount of the Company's Series B 9 3/4% Senior Notes due
2002 (the "9 3/4% Notes," and together with the 9% Notes, the "Notes").

                  In so acting, we have examined originals or copies, certified
or otherwise identified to our satisfaction, of the Registration Statement, the
Indenture dated as of October 18, 1996, between the Company and The Bank of New
York, as trustee (the "Trustee"), pursuant to which the 9% Notes will be issued
(the "9% Note Indenture"), the Indenture dated as of October 18, 1996, between
the Company and the Trustee, pursuant to which the 9 3/4% Notes will be issued
(the "9 3/4% Note Indenture," and together with the 9% Note Indenture, the
"Indentures"), the forms of the Notes included as Exhibit 4.3 to the
Registration Statement and such corporate records, agreements, documents and
other instruments, and such certificates or comparable documents of public
officials and of officers and representatives of the Company, and have made such
inquiries of such officers and representatives, as we have deemed relevant and
necessary as a basis for the opinion hereinafter set forth.


<PAGE>


ISP Holdings Inc.
February 12, 1997
Page 2

                  In such examination, we have assumed the genuineness of all
signatures, the legal capacity of natural persons, the authenticity of all
documents submitted to us as originals, the conformity to original documents of
all documents submitted to us as certified, conformed or photostatic copies and
the authenticity of the originals of such latter documents. As to all questions
of fact material to this opinion that have not been independently established,
we have relied upon certificates or comparable documents of officers and
representatives of the Company.

                  Based on the foregoing, and subject to the qualifications
stated herein, we are of the opinion that the Notes are duly authorized, and,
when duly executed on behalf of the Company, authenticated by the Trustee and
delivered in accordance with the terms of the Indentures and as contemplated by
the Registration Statement, will constitute legal, valid and binding obligations
of the Company, enforceable against it in accordance with their terms, subject
to applicable bankruptcy, insolvency, fraudulent conveyance, reorganization,
moratorium and similar laws affecting creditors' rights and remedies generally,
and subject, as to enforceability, to general principles of equity, including
principles of commercial reasonableness, good faith and fair dealing (regardless
of whether enforcement is sought in a proceeding at law or in equity).

                  The opinion expressed herein is limited to the laws of the
State of New York, the corporate laws of the State of Delaware and the federal
laws of the United States, and we express no opinion as to the effect on the
matters covered by this letter of the laws of any other jurisdiction.

                  The opinion expressed herein is rendered solely for your
benefit in connection with the transactions described herein. This opinion may
not be used or relied upon by any other person, nor may this letter or any
copies thereof be furnished to a third party, filed with a governmental agency,
quoted, cited or otherwise referred to without our prior written consent, except
that we hereby 


<PAGE>


ISP Holdings Inc.
February 12, 1997
Page 3



consent to the use of this letter as an exhibit to the Registration Statement.
We further consent to the reference to our name under the caption "Legal
Matters" in the prospectus which is a part of the Registration Statement.

                                            Very truly yours,

                                            /s/Weil, Gotshal & Manges, LLP




<PAGE>

                   [Letterhead of Weil, Gotshal & Manges LLP]


                                            February 3, 1997

WRITER'S DIRECT LINE

ISP Holdings Inc.
818 Washington Street
Wilmington, Delaware  19801

Ladies & Gentlemen:

                  You have requested our opinion regarding certain federal
income tax consequences of (i) the exchanges pursuant to the offers (the
"Exchange Offers") by ISP Holdings Inc. (the "Company") of (a) its 9% Senior
Notes due 2003 (the "Old 9% Notes") for its Series B 9% Senior Notes due 2003
(the "New 9% Notes) and (b) its 9 3/4% Senior Notes due 2002 (the "Old 9 3/4%
Notes") for its Series B 9 3/4% Senior Notes due 2002 (the "New 9 3/4% Notes")
and (ii) the ownership, sale and redemption of the New 9% and the New 9 3/4%
Notes. (The "Old Notes" and "New Notes" being referred to hereinafter as,
collectively, the Old 9% Notes and the Old 9 3/4% Notes and the New 9% Notes and
the New 9 3/4% Notes, respectively.)

                  In formulating our opinion as to the matters certified, we
have examined such documents as we have deemed appropriate, including the
Registration Statement of the Company on Form S-4 (Registration No. 333-17827)
dated December 13, 1996, filed with the Securities and Exchange Commission
pursuant to the Securities Act of 1933, as amended to the date hereof (such
Registration Statement as so amended being referred to hereinafter as the
"Registration Statement"). Also, we have obtained such additional information as
we have deemed relevant and necessary through consultation with various officers
and representatives of the Company.

                  The terms of the Exchange Offers, of the Old Notes and of the
New Notes, in each case as set forth in the Registration Statement, are
incorporated herein by reference.


<PAGE>


                  Based upon the terms of the Exchange Offers of the Old Notes
and of the New Notes, as set forth in the Registration Statement, it is our
opinion that the legal discussion of the material federal income tax
consequences of consummating the Exchange Offers and holding and disposing of
the New Notes, as set forth under the heading "Federal Income Tax
Considerations" in the Registration Statement, is accurate in all material
respects.

                  The foregoing opinion is based on current provisions of the
Internal Revenue Code of 1986, as amended, the Treasury Regulations promulgated
and proposed thereunder, published pronouncements of the Internal Revenue
Service, and case law, any of which may be changed at any time with retroactive
effect. No opinion is expressed on any matters other than those specifically
referred to herein.

                  We hereby consent to your filing this opinion as an exhibit to
the Registration Statement and to the reference to our firm therein.

                                            Very truly yours,

                                            /S/Weil, Gotshal & Manges LLP



<PAGE>

                              TAX SHARING AGREEMENT

               THIS TAX SHARING AGREEMENT made as of the 1st day of January,
1997, by and among ISP Holdings Inc., a Delaware corporation ("Holdings"),
International Specialty Products Inc., a Delaware corporation ("ISP"), and each
of the following Delaware corporations: Bluehall Incorporated, ISP (Puerto Rico)
Inc., ISP Chemicals Inc., ISP Environmental Services Inc., ISP Filters Inc., ISP
Fine Chemicals Inc., ISP Global Technologies Inc., ISP International Corp., ISP
International Filters Inc., ISP Investments Inc., ISP Management Company Inc.,
ISP Mineral Products Inc., ISP Minerals Inc., ISP Newark Inc., ISP Real Estate
Company, Inc., ISP Realty Corporation, ISP Technologies Inc., ISP Van Dyk Inc.,
and Verona Inc.;

               WHEREAS, Holdings is the common parent of an affiliated group of
corporations within the meaning of Section 1504(a) of the Internal Revenue Code
of 1986, as amended (the "Code") and ISP is a member of said affiliated group;

               WHEREAS, Holdings and ISP wish to provide for the allocation
among them of the consolidated federal income tax liability of said affiliated
group and certain related matters;

<PAGE>


               NOW, THEREFORE, in consideration of the foregoing premises and of
the mutual covenants contained herein, it is agreed as follows:

               1. Definitions

                  a. Where applicable, terms used in this Agreement shall have
the meanings ascribed to them in, and shall be interpreted in accordance with,
the Code, and the regulations and rulings issued thereunder, as in effect from
time to time.

                  b. For purposes of this Agreement, the terms set forth below
shall be defined as follows:

                      (i) Holdings Group -- Holdings, ISP and all corporations
(whether now existing or hereafter formed or acquired) that at the time join
with Holdings (or any successor common parent corporation) in filing a
consolidated federal income tax return.

                      (ii) Parent -- Holdings, or any successor common parent
corporation of the Holdings Group.

                      (iii) ISP -- ISP, or any successor corporation.

                      (iv) ISP Group -- ISP and any subsidiary corporation
(whether now existing or hereafter formed or acquired) which would be included
in the affiliated group of corporations (as defined in Section 1504(a) of the
Code) of


                                       2

<PAGE>


which ISP would be the common parent but for the inclusion of ISP in the
Holdings Group.

                      (v) Holdings Group Actual Tax Liability -- The
consolidated federal income tax liability reported on the consolidated federal
income tax return filed by the Holdings Group for the taxable year.

                      (vi) ISP Group Tax Liability -- The hypothetical
consolidated federal income tax liability, determined at the end of the taxable
year, of the ISP Group computed as if the ISP Group had filed its own
consolidated federal income tax return for such taxable year and all prior
taxable years beginning January 1, 1997 or thereafter during the term of this
Agreement; provided, that an item which was not taken into account in
calculating the ISP Group Tax Liability in any such prior year by reason of the
limitations set forth in this definition shall be carried forward to the
subsequent year (if the carryforward of such item shall not have expired under
applicable provisions of the Code) and shall be taken into account in computing
the ISP Group Tax Liability in such subsequent year, subject to the limitations
set forth in this definition: (1) subject to the modifications specified in
Treas. Reg. Sec. 1.1552-1(a)(2)(ii), other than the modifications specified in
Treas. Reg. Sec. 1.1552-1(a)(2)(ii)(a) and Treas. Reg. Sec.

                                       3

<PAGE>


1.1552-1(a)(2)(ii)(b); (2) using the highest marginal federal income tax
corporate rate applicable to such taxable year; (3) using the same elections and
methods of accounting as are used with respect to the ISP Group in the
determination of the Holdings Group Actual Tax Liability; (4) using an amount of
carryback and carryforward of ISP Group deduction, loss or credit to offset the
ISP Group's hypothetical consolidated federal taxable income (or, in the case of
credits against tax, liability for tax) after taking into account all items of
deduction, loss or credit of all members of the Holdings Group for the current
taxable year; (5) except in the case of foreign tax credits, using an amount of
the ISP Group deduction, loss or credit (whether currently or as a carryback or
carryforward) to offset the ISP Group's hypothetical consolidated federal
taxable income (or, in the case of credits against tax, liability for tax) only
when and to the extent such deduction, loss or credit reduces the Holdings Group
Actual Tax Liability or reduces the Holdings Group actual consolidated federal
taxable income for such year during the term of this Agreement (taking any
carryback or carryforward of such deduction, loss or credit into account on a
pro rata basis with those of all members of the Holdings Group other than the
ISP Group); provided, that the limitation in this clause (5) 

                                       4

<PAGE>



shall not apply to those items ("ISP Group Excepted Items") of deduction, loss
or credit for the taxable year or those items comprising the net operating loss
deduction, in both cases to the extent such items are not subject to a specific
limitation under the Code (e.g., in the case of an ISP Group capital loss, the
limitation in this clause (5) shall apply (i.e., it can be used only when and to
the extent such loss reduces the Holdings Group Actual Tax Liability or reduces
the Holdings Group actual consolidated federal taxable income for such year
during the term of this Agreement) and in the case of an ordinary and necessary
business expense of the ISP Group the limitation in this clause (5) shall not
apply); (6) using an amount of the ISP Group foreign tax credit in any taxable
year to offset the ISP Group's hypothetical consolidated federal tax liability
for such year as follows: (A) if the Holdings Group Actual Tax Liability for
such taxable year (determined without regard to the ISP Group's foreign tax
credit for such year) does not exceed $12,000,000, using an amount of the ISP
Group's foreign tax credit generated in such taxable year not to exceed
$12,000,000; provided, if the Holdings Group Actual Tax Liability for such
taxable year exceeds zero by reason of income attributable to ISP, the amount of
ISP's foreign tax credit utilized in such taxable year would be reduced by

                                       5

<PAGE>


the amount of such excess; (B) if the Holdings Group Actual Tax Liability for
such taxable year (determined without regard to the ISP Group's foreign tax
credit for such year) exceeds $12,000,000, using an amount of the ISP Group's
foreign tax credit generated in such taxable year not to exceed the amount of
foreign tax credit actually utilized by Parent to reduce the Holdings Group
Actual Tax Liability for such taxable year (taking such credit into account on a
pro rata basis with those of all members of the Holdings Group other than the
ISP Group for such taxable year, but prior to taking into account any
carryforward of credits generated in prior taxable years); and (C) using an
amount of carryback and carryforward of the ISP Group's foreign tax credit only
when and to the extent such credit reduces the Holdings Group Actual Tax
Liability during the term of this Agreement (taking such carryforward or
carryback into account on a pro rata basis with those of all members of the
Holdings Group other than the ISP Group); and (7) without regard to any change
or adjustment to the tax attributes, including basis in assets, of any member of
the Holdings Group arising from the transactions relating to the formation of
the ISP Group. The ISP Group Tax Liability shall be determined each taxable year
by Parent in its sole discretion.


                                       6

<PAGE>


                      (vii) ISP Group Estimated Tax Liability -- ISP Group's Tax
Liability, determined through the end of each period for which estimated federal
income tax payments on a consolidated basis are due. The ISP Group Estimated Tax

Liability shall be determined each taxable year by Parent in its sole
discretion, in accordance with the principles of subparagraph 1(b)(vi) hereof.

                      (viii) ISP Group Tax Refund -- The hypothetical
consolidated federal income tax refund for any year to which the ISP Group would
be entitled, determined in accordance with the principles of subparagraph
1(b)(vi) and using an amount of carryback of ISP Group Excepted Items only when
and to the extent such deduction, loss or credit reduces the Holdings Group
Actual Tax Liability or reduces the Holdings Group actual consolidated federal
taxable income for such year during the term of this Agreement (taking such
deduction, loss or credit into account on a pro rata basis with those of all
members of the Holdings Group other than the ISP Group); provided, such loss,
deduction or credit has not been previously utilized to reduce the ISP Group Tax
Liability or the ISP Group hypothetical consolidated federal taxable income. The
ISP Group Tax Refund shall be determined each taxable year by Parent in its sole
discretion.

                                       7

<PAGE>


                      (ix) tax -- regular corporate income tax or corporate
alternative minimum tax and environmental tax together with any and all
interest, additions to tax, fines and penalties payable with respect thereto.

               2.   PAYMENTS OF CONSOLIDATED FEDERAL INCOME TAX LIABILITY;
                    FILING OF RETURNS

                    a.   Tax Payments by Parent; Filing of Returns

               Parent shall file consolidated federal income tax returns and
estimated tax returns for each taxable year during the term of this Agreement,
which returns shall include the ISP Group, and shall pay in full any tax shown
on such returns.

                    b.   Payment of ISP Group Tax Liability

               For each taxable year or portion thereof during which ISP is
included in a consolidated federal income tax return with Parent, ISP will pay
to Holdings an amount equal to the ISP Group Tax Liability. To the extent that
the obligation to pay such amount has not been fully satisfied pursuant to
paragraph 2(c), ISP shall pay any such remaining amount to Holdings no later
than five (5) days prior to the due date for the filing by Parent of the
consolidated 

                                       8

<PAGE>


federal income tax return for the Holdings Group (without regard to
extensions).



               c.   Estimated Payments

               On any date on which Parent is to make an estimated federal
income tax payment of the Holdings Group on a consolidated basis, ISP will make
an estimated payment to Holdings in an amount equal to the ISP Group Estimated
Tax Liability (reduced by all prior payments required to be made by ISP under
this paragraph 2(c) with respect to the same taxable year). If the total of such
estimated payments made by ISP to Holdings with respect to a taxable year shall
be in excess of the liability of ISP to Holdings pursuant to paragraph 2(b) for
such taxable year, Holdings shall pay the amount of such excess to ISP, (x) to
the extent that such excess (or part thereof) represents all or part of a tax
refund to be received by the Holdings Group, no later than five (5) days after
the receipt of such refund with an allocable share of interest received thereon
(net of tax; provided, such interest shall not be treated as an item of income
of the ISP Group under this Agreement); (y) to the extent such excess (or part
thereof) represents all or part of a credit against the Holdings Group's
estimated tax for a succeeding taxable year, no later than five (5) days after
such estimated tax payments against which such excess is


                                       9

<PAGE>


credited is to be paid by the Parent; or (z) to the extent (x) and (y) do not
apply to such excess (or part thereof), no later than the date on which Parent
files the consolidated federal income tax return for the Holdings Group.

               d.   Tax Refunds

                      (i) Holdings shall pay to ISP the amount of any ISP Group
Tax Refund for each taxable year ending after the date hereof.

                      (ii) The payments described in this paragraph 2(d) shall
be made no later than (i) in the case of an actual refund to which the Holdings
Group is entitled, five (5) days after such refund is received by Parent on
behalf of the Holdings Group or (ii) otherwise, five (5) days after the date on
which Parent files the consolidated federal income tax return for the Holdings
Group.

               3.   CHANGES IN TAX LIABILITY

               a. If any of the Holdings Group consolidated federal income tax
returns for taxable years of Holdings ending on or after January 1, 1997 is
changed or otherwise adjusted (including, without limitation, by reason of the
filing of an amended return, a "final determination" as defined in Section
1313(a) of the Code or any of the events specified in Section 6213(b) or (d) of
the Code), then the amount of the 


                                       10


<PAGE>

events specified in Section 6213(b) or (d) of the Code), then the amount of
the payment required (1) from ISP to Holdings under paragraph 2(b) or
(2) from Holdings to ISP under paragraph 2(d), as the case may be, shall
be recomputed by substituting the amount of the Holdings Group Actual
Tax Liability (or the Holdings Group actual consolidated federal taxable
income), the ISP Group Tax Liability (or the ISP Group hypothetical
consolidated federal taxable income), or the ISP Group Tax Refund after
the adjustments described above in place of the Holdings Group Actual
Tax Liability (or the Holdings Group actual consolidated federal taxable
income), the ISP Group Tax Liability (or the ISP Group hypothetical
consolidated federal taxable income), or the ISP Group Tax Refund as
previously computed. Not later than (i) five (5) days prior to the due
date for any additional payment of tax by the Holdings Group or five (5)
days after the receipt of a refund or (ii) five (5) days after the event
giving rise to the recomputation if such event will not result in the
payment of additional tax or the receipt of a refund, ISP shall pay to
Holdings, or Holdings shall pay to ISP, as the case may be, the
difference between the new ISP Group Tax Liability (or Refund) and the
amounts previously paid. The parties recognize that such new liability
(or Refund) for


                                       11

<PAGE>

any taxable year is not necessarily the Holdings Group's or the ISP Group's
final liability for that taxable year, and may be recomputed in accordance with
this paragraph 3(a) more than once.

               b. If any of the Holdings Group consolidated federal income tax
returns for taxable years of Holdings ending on or before January 1, 1997 is
changed or otherwise adjusted (including, without limitation, by reason of the
filing of an amended return, a "final determination" as defined in Section 1313
(a) of the Code or any of the events specified in Section 6213(b) or (d) of the
Code), then ISP shall pay to Holdings an amount equal to any tax that would be
payable by reason of any such change or adjustment relating to the business or
assets of ISP (other than taxes, if any, arising from the transactions relating
to the formation of ISP Group). Such payments shall be determined by Parent, in
its sole discretion, in accordance with principles analogous to these set forth
herein and shall be made not later than (i) five (5) days prior to the due date
for any additional payment of tax by the Holdings Group or (ii) five (5) days
after the event giving rise to the change or adjustment if such event will not
result in the payment of additional tax. The parties recognize that such payment
for any taxable year is not necessarily the ISP Group's 


                                       12

<PAGE>



final liability under this paragraph 3(b) for that taxable year, and may be
recomputed in accordance with this paragraph 3(b) more than once.

               c. Payments made pursuant to paragraph (a) shall include an
allocable portion of any interest paid or credited by the Internal Revenue
Service (net of tax; provided, such interest shall not be treated as an item of
income of the ISP Group); payments made pursuant to paragraphs (a) and (b) shall
not themselves bear interest.

               4.   NEW MEMBERS

               If sufficient stock of any corporation is acquired hereafter by
any member of the ISP Group so that the corporation becomes a member of the ISP
Group ("New Member"), the New Member shall become a party to this Agreement by
delivering to the Parent a written instrument to such effect. ISP shall use its
best efforts, if so requested by Holdings, to cause the delivery of such written
instrument and the execution of Form 1122, Authorization and Consent of
Subsidiary Corporation to be Included in a Consolidated Income Tax Return. The
parties hereto hereby agree to the inclusion of any such New Member as a party
to this Agreement.

                                       13

<PAGE>


               5.   ALLOCATION OF STATE AND LOCAL
                    INCOME TAX LIABILITY

                    a. In the event that (i) any member of the ISP Group and
(ii) at least one member of the Holdings Group not including any member
of the ISP Group elect or are required to file consolidated, combined or
unitary state or local income tax returns or otherwise become liable for
state or local income taxes determined on a consolidated, combined or
unitary basis, principles analogous to those set forth herein for the
payment of consolidated federal income tax liability and refunds thereof
shall be used to determine the respective shares of such taxes and the
amount of any payments due ISP from Holdings on behalf of all members of
the Holdings Group other than the ISP Group and the amount and timing of
payments to be made in respect thereof.

               b. If the Holdings Group consolidated, combined or unitary state
or local income tax returns or the separate state or local income tax returns 
of Holdings or any member of the Holdings Group, in both cases for taxable 
years of Holdings ending on or before January 1, 1997 are changed or otherwise 
adjusted (including, without limitation, by reason of the filing of an amended 
return, a "final determination" as defined in Section 1313(a) of the Code or 
any of the events specified in Section 6213(b) or (d) of the Code), then ISP 
shall pay to Holdings an amount 

                                       14

<PAGE>



equal to any tax that would be payable by reason of any such change or
adjustment relating to the business or assets of the ISP Group (other than
taxes, if any, arising from the transactions relating to the formation of the
ISP Group). Such payments shall be determined by Parent, in its sole discretion,
in accordance with principles analogous to those set forth herein and shall be
made not later than (i) five (5) days prior to the due date for any additional
payment of tax by the Holdings Group or (ii) five (5) days after the event
giving rise to the change or adjustment if such event will not result in the
payment of additional tax. The parties recognize that such payment for any
taxable year is not necessarily the ISP Group's final liability under this
paragraph 5(b) for that taxable year, and may be recomputed in accordance with
this paragraph 5(b) more than once. Payments made pursuant to this paragraph (b)
shall not themselves bear interest.

               6.   PAYMENT

               a. Any payment required by ISP to Holdings under paragraph 2(b),
paragraph 2(c), paragraph 9(c) or paragraph 9(d) shall be made (i) first, by
reducing the amount of any account payable of Holdings to the ISP Group 

                                       15

<PAGE>


created under paragraph 6(b) (but not below zero) and (ii) thereafter in cash.

               b. Any payment required by Holdings to ISP pursuant to paragraph
2(d) shall be made at the option of Holdings (i) in cash or (ii) by entering or
increasing an account payable of Holdings to ISP on the books of account of
Holdings; provided that Holdings shall pay to ISP the amount of any ISP Group
Tax Refund for a taxable year ending after the date hereof in cash if and to the
extent that the Holdings Group receives a refund from a taxing authority for
such taxable year, together with an allocable share of any interest received
with respect thereto (net of tax; provided, such interest shall not be treated
as an item of income of the ISP Group under this Agreement); and provided,
further, that Holdings shall not pay to ISP an amount greater than the amount of
refund with interest actually received thereon (net of tax; provided, such
interest shall not be treated as an item of income of the ISP Group under this
Agreement) received from the taxing authority.

               c. Any account payable created under this paragraph 6 from
Holdings to ISP shall be due on the earlier of (i) such date as Holdings no
longer owns (directly or indirectly) more than 50% of the outstanding stock of
ISP or (ii) the dates of the filing of federal income tax returns 

                                       16

<PAGE>


of ISP for taxable years of ISP following the last taxable year in which it was
a member of the Holdings Group to the extent each such return reflects a tax

liability which would have reduced the account payable under paragraph 6(a) were
ISP still a member of the Holdings Group and subject to the terms of this
Agreement.


               7.   SPECIAL PROVISIONS REGARDING ISP
                    GROUP'S FOREIGN TAX CREDIT

               a. At the end of each taxable year, Holdings shall enter or
increase an account payable of Holdings to ISP in an amount equal to the excess,
if any, of the ISP Group's foreign tax credits for such year (subject to the
foreign tax credits being allowed under ISP Group's separate foreign tax credit
limitation, taking into account carrybacks and carryforwards under Section 904
of the Code) over the ISP Group's foreign tax credits taken into account under
subparagraph 1(b)(vi)(6)(A) or subparagraph 1(b)(vi)(6)(B) (such excess being
referred to as "Excess Foreign Tax Credits").

               b. Such account payable shall be reduced (i) at the end of each
taxable year of ISP during the term of this Agreement to the extent that Excess
Foreign Tax Credits are utilized under subparagraph 1(b)(vi)(6)(C) and (ii) at
the end of each taxable year of ISP following the 

                                       17

<PAGE>


last taxable year in which it was a member of the Holdings Group to the extent
the federal income tax return of ISP for such taxable year reflects a tax
liability which is reduced by such Excess Foreign Tax Credits (taking such
Excess Foreign Tax Credits into account prior to those of ISP and all other
members of the ISP Group).

               c. The balance of such account payable, if any, shall be paid
from time to time on the date that is thirty (30) days following the expiration
of the statute of limitations on assessment of tax for the last year to which
such Excess Foreign Tax Credits or item thereof may be carried forward.

               8.   PROCEDURAL MATTERS

               Parent shall prepare and file the consolidated federal income tax
returns, consolidated, combined or unitary state or local income tax returns and
any other returns, documents or statements required to be filed with respect to
the determination of the consolidated, combined or unitary federal, state or
local income tax liability of the Holdings Group or members thereof for all
taxable years of the Holdings Group or members thereof (including taxable years
ending prior to or including the date hereof). In its sole discretion, Parent
shall have the right to make all 

                                       18

<PAGE>



decisions with respect to such returns and all matters relating to the federal,
state or local income tax liability of the Holdings Group and members thereof
for all taxable years of the Holdings Group or members thereof (including
taxable years ending prior to or including the date hereof) including, without
limitation, the right (a) to determine (i) the manner in which such returns,
documents or statements shall be prepared and filed, including, without
limitation, the manner in which any item of income, gain, loss, deduction or
credit shall be reported and whether any amended returns shall be filed, (ii)
whether any filing extensions may be requested and (iii) the elections that will
be made by any member, (b) to contest, compromise or settle any adjustment or
deficiency proposed, asserted or assessed as a result of any audit of such
returns, (c) to file, prosecute, compromise or settle any claim for refund and
(d) to determine whether any refunds, to which the Holdings Group may be
entitled, shall be paid by way of refund or credited against the tax liability
for the affiliated group. Each member of the Holdings Group hereby irrevocably
appoints Parent as its agent and attorney-in-fact to take such action (including
the execution of documents) as Parent may deem appropriate to effect the
foregoing.

                                       19

<PAGE>


               9.   TERMINATION OF AFFILIATION.

               a. In the event that any member of the ISP Group ceases to be
included in the Holdings Group ("Former Member"), the Parent and the Former
Member shall furnish each other with information required to prepare (i) the
consolidated federal income tax return of the Holdings Group for the last
taxable year in which the Former Member had been included in the Holdings Group
and (ii) the federal income tax returns for all taxable years thereafter of the
Former Member (and its predecessors and subsidiaries) and the Parent,
respectively, in which the tax liability of either may be affected by their
former affiliation (including, for example, the apportionment of any
consolidated net operating or capital loss or investment or foreign tax credit
carryover to the Former Member). The Former Member shall not, without the prior
written consent of the Parent (which may be withheld by Parent in its sole
discretion), file an application for a carryback adjustment of the tax, for a
taxable year in which the Former Member was included in the Holdings Group and a
consolidated federal income tax return was filed, by reason of a net operating
loss deduction. The Former Member may file an application for a carryback
adjustment of the tax for a taxable year in which the Former Member was included
in the 

                                       20

<PAGE>

Holdings Group and a consolidated federal income tax return was filed by reason
of a capital loss or tax credit carryback and shall be entitled to that portion
of the actual refund that is attributable to the Former Member under the
consolidated return regulations; provided, however, that the Former Member shall
not be entitled to any portion of such refund to the extent the items giving

rise to such carryback have been previously utilized to reduce the ISP Group Tax
Liability (or the ISP Group hypothetical consolidated federal taxable income) or
gave rise to an ISP Group Tax Refund.

               b. The Parent and its subsidiaries and the Former Member shall
also furnish each other with all information in their hands as may be reasonably
requested by the other and relates to a taxable year in which the Former Member
had been included in the Holdings Group.

               c. If the Former Member has a carryforward of a deduction, loss
or credit to a taxable year following the last taxable year in which it joined
in the filing of a consolidated federal income tax return with the Holdings
Group which has reduced the ISP Group Tax Liability (or the ISP Group
hypothetical consolidated federal taxable income) or gave rise to an ISP Group
Tax Refund, then ISP shall pay 

                                       21

<PAGE>


to Holdings, at the time such carryforward is actually utilized, an amount equal
to the benefit derived therefrom.

               d. If the Former Member, in a taxable year following the last
taxable year in which it joined in the filing of a consolidated federal income
tax return with the Holdings Group, realizes any tax benefit by reason of any
change or adjustment to the tax attributes, including basis in assets, of any
member of the Holdings Group arising from the transactions relating to the
formation of the ISP Group, then ISP shall pay to Holdings at the time such
benefits are actually utilized the amount of benefit derived therefrom.

               e. Payments which would have been required under paragraphs 2, 3
or 5 to or by a Former Member, were the Former Member still a member of the
Holdings Group, and with respect to taxable year(s) for which the Former Member
was a member of the Holdings Group, shall be made in accordance with principles
analogous to those set forth in such paragraph(s) and at the time(s) set forth
therein.

               10.  DETERMINATIONS

               In the case of a dispute, all determinations required hereunder
for each taxable year shall be made by the independent public accountants
regularly employed by Parent at the time the return is filed for such taxable

                                       22

<PAGE>


year. Such determination shall be binding and conclusive upon the parties for
the purposes hereof.

               11.  EFFECTS OF AGREEMENT


               a. As among Parent, and the ISP Group, the provisions of this
Agreement shall fix the liability of each to the other as to the matters covered
hereunder, even if such provisions are not controlling for tax or other purposes
(including, but not limited to, the computation of earnings and profits for
federal income tax purposes), and even if Parent and other corporations which
now are, or which from time to time may become, members of the Holdings Group
enter into other arrangements for the allocation of the portion of the total tax
liability of the Holdings Group which is allocable to them.


               b. This Agreement shall be effective as of January 1, 1997 and
shall remain in effect for each taxable year ending after the date hereof during
which ISP or any of its domestic subsidiaries, as the case may be, is included
in a consolidated federal income tax return filed by the Parent; provided,
however, that the provisions of paragraphs 2, 3, 5, 6, 7, 9 and 12 shall survive
until thirty (30) days after the expiration of the statute of limitations on
assessment of tax for the last year in which ISP or any of

                                       23

<PAGE>


its domestic subsidiaries, as the case may be, was a member of the Holdings
Group.

               12.  INDEMNITY

               a. Each member of the ISP Group agrees, jointly and severally, to
indemnify Parent and each other member of the Holdings Group for the amount of
any tax paid by Parent or such other member (whether by application of Treas.
Reg. Sec. 1.1502-6 or similar provision of state or local law or otherwise)
which constitutes any unpaid ISP Group Tax Liability under this Agreement.

               b. Parent and each signatory to this Agreement (other than
members of the ISP Group) agrees, jointly and severally, to indemnify the ISP
Group for the amount of any tax paid by the ISP Group (whether by application of
Treas. Reg. Sec. 1.1502-6 or similar provision of state or local law or
otherwise ) in excess of the amount which constitutes any ISP Group Tax
Liability.

               c. Any indemnity payable pursuant to paragraph 12(a) or 12(b)
hereof shall be payable on demand by the indemnitor(s) immediately after the
indemnitee pays such indemnified liability and provides proof of payment to the
indemnitor.

                                       24

<PAGE>


               If an indemnity is not paid within five (5) business days
following a demand, the amount owed shall bear interest at the Base Rate (as

that term is defined in the Credit Agreement, dated as of July 26, 1996, among
International Specialty Products Inc., its principal domestic subsidiaries, The
Chase Manhattan Bank (National Association), as Administrative Agent and the
Banks named therein) plus two percent.

               13.  MISCELLANEOUS PROVISIONS

               a. This Agreement contains the entire understanding of the
parties hereto with respect to the subject matter contained herein. No
alteration, amendment or modification of any of the terms of this Agreement
shall be valid unless made by an instrument signed in writing by an authorized
officer of each party.

               b. This Agreement has been made in and shall be construed and
enforced in accordance with the laws of the State of Delaware from time to time
obtaining.

               c. This Agreement shall be binding upon and inure to the benefit
of each party hereto and its respective successors and assigns.

               d. All notices and other communications hereunder shall be deemed
to have been duly given if 

                                       25

<PAGE>


delivered by hand or mailed, certified or registered mail, with postage prepaid
addressed to the party to which the notice or other communication is given at
1361 Alps Road, Wayne, New Jersey 07470.

               e. This Agreement may be executed simultaneously in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

               f. The headings of the paragraphs of this Agreement are inserted
for convenience only and shall not constitute a part hereof.

                                       26

<PAGE>


               IN WITNESS WHEREOF, the parties hereto have caused this Agreement
to be duly executed as of the date first above written.

                            ISP HOLDINGS CORPORATION

                             By: /s/ Mark A. Presto
                                 ---------------------------
                               Its: Vice President
                                   --------------------------

                             INTERNATIONAL SPECIALTY
                                  PRODUCTS INC.

                             By: /s/ Mark A. Presto
                                 ---------------------------
                               Its: Vice President
                                   --------------------------

                              BLUEHALL INCORPORATED
                              ISP (PUERTO RICO) INC.
                              ISP CHEMICALS INC.
                              ISP ENVIRONMENTAL SERVICES INC.
                              ISP FILTERS INC.
                              ISP FINE CHEMICALS INC.
                              ISP GLOBAL TECHNOLOGIES INC.
                              ISP INTERNATIONAL CORPORATION
                              ISP INTERNATIONAL FILTERS INC.
                              ISP INVESTMENTS INC.
                              ISP MANAGEMENT COMPANY, INC.
                              ISP MINERAL PRODUCTS INC.
                              ISP MINERALS INC.
                              ISP NEWARK INC.
                              ISP REAL ESTATE COMPANY, INC.
                              ISP REALTY CORPORATION
                              ISP TECHNOLOGIES INC.
                              ISP TECHNOLOGIES INC.
                              ISP VAN DYK INC.
                              VERONA INC.

                             By: /s/ Mark A. Presto
                                 ---------------------------
                              Their: Vice President
                                     ------------------------

                                       27



<PAGE>

                                                                    EXHIBIT 23.1



                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


ISP Holdings Inc.:

As independent public accountants, we hereby consent to the use of our report
and all references to our firm included in or made a part of this registration
statement.





                                                  /s/ ARTHUR ANDERSEN LLP
                                                      ARTHUR ANDERSEN LLP



Roseland, New Jersey
February 13, 1997



<TABLE> <S> <C>


<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL
INFORMATION EXTRACTED FROM THE FORM S-4
REGISTRATION STATEMENT OF ISP HOLDINGS INC.
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE
TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED>
<MULTIPLIER>                  1,000
       
<S>                           <C>
<PERIOD-TYPE>                 9-MOS
<FISCAL-YEAR-END>             DEC-31-1995
<PERIOD-END>                  SEP-29-1996
<CASH>                        11,767
<SECURITIES>                  99,952
<RECEIVABLES>                 72,764
<ALLOWANCES>                  2,916
<INVENTORY>                   98,354
<CURRENT-ASSETS>              572,179
<PP&E>                        482,416
<DEPRECIATION>                184,250
<TOTAL-ASSETS>                1,537,288
<CURRENT-LIABILITIES>         159,134
<BONDS>                       239,760
         0
                   0
<COMMON>                      0
<OTHER-SE>                    61,653
<TOTAL-LIABILITY-AND-EQUITY>  1,537,288
<SALES>                       544,135
<TOTAL-REVENUES>              544,135
<CGS>                         320,295
<TOTAL-COSTS>                 320,295
<OTHER-EXPENSES>              0
<LOSS-PROVISION>              0
<INTEREST-EXPENSE>            21,879
<INCOME-PRETAX>               98,202
<INCOME-TAX>                  35,647
<INCOME-CONTINUING>           51,753
<DISCONTINUED>                26,215
<EXTRAORDINARY>               (8,186)
<CHANGES>                     0
<NET-INCOME>                  69,782
<EPS-PRIMARY>                 0
<EPS-DILUTED>                 0
        


</TABLE>


<PAGE>

                              LETTER OF TRANSMITTAL
                                ISP HOLDINGS INC.
                            OFFER FOR ALL OUTSTANDING
                            9% SENIOR NOTES DUE 2003
                                 IN EXCHANGE FOR
                        SERIES B 9% SENIOR NOTES DUE 2003

              PURSUANT TO THE PROSPECTUS, DATED FEBRUARY    , 1997

- --------------------------------------------------------------------------------

THE EXCHANGE OFFER WILL EXPIRE AT 12:00 MIDNIGHT NEW YORK CITY TIME, ON 
MARCH  , 1997, (THE 'EXPIRATION DATE'). TENDERS MAY BE WITHDRAWN PRIOR 
TO 12:00 MIDNIGHT, NEW YORK CITY TIME, ON THE EXPIRATION DATE.

- --------------------------------------------------------------------------------


<TABLE>
<S>                                          <C>                                     <C>
                                                  The Bank of New York

   By Registered or Certified Mail:          Facsimile Transmission Number:            By Hand/Overnight Delivery:
         The Bank of New York                  (Eligible Institutions and                  The Bank of New York      
        101 Barclay Street - 7E                 Withdrawal Notices Only)                    101 Barclay Street       
       New York, New York 10286                      (212) 571-3080                  Corporate Trust Services Window 
     Attn: Reorganization Section                 Confirm by Telephone:                        Ground Level          
                                                     (212) 815-2742                      New York, New York 10286    
                                                                                       Attn: Reorganization Section  
                                                                                    
                                                  For Information Call:
                                                     (212) 815-6333
</TABLE>

         DELIVERY OF THIS INSTRUMENT TO AN ADDRESS OTHER THAN AS SET FORTH
ABOVE, OR TRANSMISSION OF INSTRUCTIONS BY ELIGIBLE INSTITUTIONS VIA FACSIMILE
OTHER THAN AS SET FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.

     The undersigned acknowledges that he or she has received the Prospectus,
dated February   , 1997 (the 'Prospectus'), of ISP Holdings Inc., a Delaware
corporation (the 'Company'), and this Letter of Transmittal (the 'Letter'),
which together constitute the Company's offer (the 'Exchange Offer') to exchange
an aggregate principal amount at maturity of up to $325,000,000 of Series B 9%
Senior Notes due 2003 (the 'New Notes') of the Company for a like principal
amount at maturity of the issued and outstanding 9% Senior Notes due 2003 (the
'Old Notes') of the Company from the holders thereof.

     For each Old Note accepted for exchange, the holder of such Old Note will
receive a New Note having a principal amount at maturity equal to that of the
surrendered Old Note. Holders whose Old Notes are accepted for exchange will
receive accrued interest thereon to, but not including, the date of issuance of
such New Notes, such interest to be payable with the first interest payment on

the New Notes. Interest on the New Notes will accrue from their respective dates
of issuance. Holders of Old Notes accepted for exchange will be deemed to have
waived the right to receive any other payments or interest on the Old Notes. The
Company reserves the right, at any time or from time to time, to extend the
Exchange Offer at its discretion, in which event the term 'Expiration Date'
shall mean the latest time and date to which the Exchange Offer is extended. The
Company shall notify the holders of the Old Notes of any extension by means of a
press release or other public announcement prior to 9:00 A.M., New York City
time, on the next business day after the previously scheduled Expiration Date.

     This Letter is to be completed by a holder of Old Notes either if
certificates are to be forwarded herewith or if a tender of certificates for Old
Notes, if available, is to be made by book-entry transfer to the account
maintained by The Bank of New York (the 'Exchange Agent') at The Depository
Trust Company (the 'Book-Entry Transfer Facility') pursuant to the procedures
set forth in 'The Exchange Offers--Book-Entry Transfer' section of the
Prospectus. Holders of Old Notes whose certificates are not immediately
available, or who are unable to deliver their certificates or confirmation of
the book-entry tender of their Old Notes into the Exchange Agent's account at
the Book-Entry Transfer Facility (a 'Book-Entry Confirmation') and all other
documents required by this Letter to the Exchange Agent on or prior to the
Expiration Date, must tender their Old Notes according to the guaranteed
delivery procedures set forth in 'The Exchange Offers--Guaranteed

<PAGE>

Delivery Procedures' section of the Prospectus. See Instruction 1. Delivery of
documents to the Book-Entry Transfer Facility does not constitute delivery to
the Exchange Agent.

         The undersigned has completed the appropriate boxes below and signed
this Letter to indicate the action the undersigned desires to take with respect
to the Exchange Offer.

         List below the Old Notes to which this Letter relates. If the space
provided below is inadequate, the certificate numbers and principal amount at
maturity of Old Notes should be listed on a separate signed schedule affixed
hereto.

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------
                    DESCRIPTION OF OLD NOTES                               1                  2                   3
- -----------------------------------------------------------------------------------------------------------------------------
                                                                                          Aggregate
                                                                                          Principal           Principal
                                                                                          Amount at           Amount at
        Name(s) and Address(es) of Registered Holder(s)              Certificate         Maturity of          Maturity
                   (Please fill in, if blank)                          Number(s)*        Old Note(s)          Tendered**
- -----------------------------------------------------------------------------------------------------------------------------
<S>                                                                <C>                   <C>                 <C>

                                                                   Total
- -----------------------------------------------------------------------------------------------------------------------------

</TABLE>

*    Need not be completed if Old Notes are being tendered by book-entry
     transfer.

**   Unless otherwise indicated in this column, a holder will be deemed to have
     tendered ALL of the Old Notes represented by the Old Notes indicated in
     column 2. See Instruction 2. Old Notes tendered hereby must be in
     denominations of principal amount at maturity of $1,000 and any integral
     multiple thereof. See Instruction 1.



/ /  CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED BY BOOK-ENTRY TRANSFER
     MADE TO THE ACCOUNT MAINTAINED BY THE EXCHANGE AGENT WITH THE BOOK-ENTRY
     TRANSFER FACILITY AND COMPLETE THE FOLLOWING:

     Name of Tendering Institution
                                  ----------------------------------------------

     Account Number                    Transaction Code Number
                   ------------------                         ------------------

/ /  CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED PURSUANT TO A NOTICE 
     OF GUARANTEED DELIVERY PREVIOUSLY SENT TO THE EXCHANGE AGENT AND COMPLETE
     THE FOLLOWING:

     Name(s) of Registered Holder(s)
                                    --------------------------------------------

     Window Ticket Number (if any)
                                  ----------------------------------------------

     Date of Execution of Notice of Guaranteed Delivery
                                                       -------------------------

     Name of Institution which guaranteed delivery
                                                  ------------------------------

     If Delivered by Book-Entry Transfer, Complete the Following:

     Account Number                    Transaction Code Number
                   ------------------                         ------------------

/ /  CHECK HERE IF YOU ARE A BROKER-DEALER AND WISH TO RECEIVE 10 ADDITIONAL
     COPIES OF THE PROSPECTUS AND 10 COPIES OF ANY AMENDMENTS OR SUPPLEMENTS
     THERETO.

Name:
     ---------------------------------------------------------------------------

Address:
        ------------------------------------------------------------------------

        ------------------------------------------------------------------------

<PAGE>

               PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

Ladies and Gentlemen:

     1. Upon the terms and subject to the conditions of the Exchange Offer, the
undersigned hereby tenders to the Company the aggregate principal amount at
maturity of Old Notes indicated above. Subject to, and effective upon, the
acceptance for exchange of the Old Notes tendered hereby, the undersigned
hereby sells, assigns and transfers to, or upon the order of, the Company all
right, title and interest in and to such Old Notes as are being tendered
hereby.

     2. The undersigned hereby represents and warrants that the undersigned has
full power and authority to tender, sell, assign and transfer the Old Notes
tendered hereby and that the Company will acquire good and unencumbered title
thereto, free and clear of all liens, restrictions, charges and encumbrances
and not subject to any adverse claim when the same are accepted by the Company.
The undersigned hereby further represents that any New Notes acquired in
exchange for Old Notes tendered hereby will have been acquired in the ordinary
course of business of the person receiving such New Notes, whether or not such
person is the undersigned, that neither the holder of such Old Notes nor any
such other person is engaging in or intends to engage in a distribution of such
New Notes, that neither the holder of such Old Notes nor any such other person
has an arrangement or understanding with any person to participate in the
distribution of such New Notes and that neither the holder of such Old Notes
nor any such other person is an "affiliate," as defined in Rule 405 under the
Securities Act of 1933, as amended (the "Securities Act"), of the Company.

     3. The undersigned also acknowledges that the Exchange Offer is being made
in reliance on an interpretation, made to third parties, by the staff of the
Securities and Exchange Commission (the "SEC") that the New Notes issued in
exchange for the Old Notes pursuant to the Exchange Offer may be offered for
resale, resold and otherwise transferred by holders thereof (other than any
such holder that is an "affiliate" of the Company within the meaning of Rule
405 under the Securities Act), without compliance with the registration and
prospectus delivery provisions of the Securities Act, provided that such New
Notes are acquired in the ordinary course of such holders' business, such
holders are not engaging in and do not intend to engage in the distribution of
such New Notes and such holders have no arrangements with any person to
participate in the distribution of such New Notes. If the undersigned is not a
broker-dealer, the undersigned represents that it is not engaged in, and does
not intend to engage in, a distribution of New Notes. If the undersigned is a
broker-dealer that will receive New Notes for its own account in exchange for
Old Notes that were acquired as a result of market-making activities or other
trading activities, it acknowledges that it will deliver a prospectus meeting
the requirements of the Securities Act in connection with any resales of such
New Notes. However, by so acknowledging and by delivering a prospectus, the
undersigned will not be deemed to admit that it is an "underwriter" within the
meaning of the Securities Act.

     4. The undersigned may, if, and only if, it would not receive freely
tradeable New Notes in the Exchange Offer or is not eligible to participate in

the Exchange Offer, elect to have its Old Notes registered in the shelf
registration described in the Registration Rights Agreement, dated as of October
18, 1996, between the Company and Bear, Stearns & Co. Inc. (the 'Registration
Agreement') in the form filed as Exhibit 4.4 to the Registration Statement of
the Company, Registration No. 333-17827. Capitalized terms used in this
paragraph 4 and not otherwise defined herein shall have the meanings given them
in the Registration Agreement. Such election may be made by checking the box
under 'Special Registration Instructions' below. By making such election, the
undersigned agrees, as a holder of Old Notes participating in a Shelf
Registration, to comply with the Registration Agreement and to indemnify and
hold harmless the Initial Purchaser and each person, if any, who controls the
Initial Purchaser within the meaning of either Section 15 of the Securities Act
or Section 20 of the Securities Exchange Act of 1934, as amended (the 'Exchange
Act'), and the Company, each director and officer of the Company and each
person, if any, who controls the Company within the meaning of either such
Section, from and against any losses, claims, damages and liabilities or any
actions in respect thereof, to which the Initial Purchaser or any controlling
person of the Initial Purchaser, and the Company or any of its directors,
officers or controlling persons may become subject under the Securities Act, the
Exchange Act or otherwise, insofar as such losses, claims, damages, liabilities
or actions arise out of or are based upon any untrue statement or alleged untrue
statement of a material fact contained in the Registration Statement or
prospectus or in any amendment or supplement thereto or in any preliminary
prospectus relating to a Shelf Registration, or arise out of or are based upon
any omission or alleged omission to state therein a material fact necessary to
make the statements therein not misleading, but in each case only to the extent
that the untrue statement or alleged untrue statement or omission or alleged
omission was made in reliance upon and in conformity with written information
furnished to the Company by or on behalf of the undersigned specifically for
inclusion therein; and, shall reimburse, as incurred, the Company for any legal
or other expenses reasonably incurred by the Company or any director, officer or
controlling person thereof in connection with the investigation or defending or
preparing to defend against or appearing as a third-party witness in connection
with any loss, claim, damage, liability or action in respect thereof. Any such
indemnification shall be governed by the terms and subject to the conditions set
forth in the Registration Agreement, including, without limitation, the
provisions regarding notice, retention of counsel, contribution and payment of
expenses set forth therein. The above summary

<PAGE>

of the indemnification provisions of the Registration Agreement is not intended
to be exhaustive and is qualified in its entirety by the Registration Agreement.

 
     5. The undersigned will, upon request, execute and deliver any additional
documents deemed by the Company to be necessary or desirable to complete the
sale, assignment and transfer of the Old Notes tendered hereby. All authority
conferred or agreed to be conferred in this Letter and every obligation of the
undersigned hereunder shall be binding upon the successors, assigns, heirs,
executors, administrators, trustees in bankruptcy and legal representatives of
the undersigned and shall not be affected by, and shall survive, the death or
incapacity of the undersigned. This tender may be withdrawn only in accordance
with the procedures set forth in 'The Exchange Offers--Withdrawal Rights'

section of the Prospectus. See Instruction 9.
 
     6. Unless otherwise indicated in the box entitled 'Special Issuance
Instructions' below, please issue the New Notes (and, if applicable, substitute
certificates representing Old Notes for any Old Notes not exchanged) in the name
of the undersigned or, in the case of a book-entry delivery of Old Notes, please
credit the account indicated above maintained at the Book-Entry Transfer
Facility. Similarly, unless otherwise indicated under the box entitled 'Special
Delivery Instructions' below, please send the New Notes (and, if applicable,
substitute certificates representing Old Notes for any Old Notes not exchanged)
to the undersigned at the address shown above in the box entitled 'Description
of Old Notes.'

 
     The undersigned acknowledges that the Exchange Offer is subject to the more
detailed terms set forth in the Prospectus and, in case of any conflict between
the terms of the Prospectus and this Letter, the Prospectus shall prevail.


<PAGE>

     THE UNDERSIGNED, BY COMPLETING THE BOX ENTITLED "DESCRIPTION OF OLD NOTES"
ABOVE AND SIGNING THIS LETTER, WILL BE DEEMED TO HAVE TENDERED THE OLD NOTES
AS SET FORTH IN SUCH BOX ABOVE.

<TABLE>
<S>                                                           <C>

- -------------------------------------------------------       ------------------------------------------------------------
            SPECIAL ISSUANCE INSTRUCTIONS                                     SPECIAL DELIVERY INSTRUCTIONS
             (See Instructions 3 and 4)                                        (See Instructions 3 and 4)

  To be completed ONLY if certificates for Old Notes not          To be completed ONLY if certificates for Old Notes not
exchanged and/or New Notes are to be issued in the name of      exchanged and/or New Notes are to be sent to someone other than
someone other than the person or persons whose signature(s)     the person or persons whose signature(s) appear(s) on this Letter
appear(s) on this Letter below, or if Old Notes delivered by    below or to such person or persons at an address other than
book-entry transfer which are not accepted for exchange are     shown in the box entitled "Description of Old Notes" on this
to be returned by credit to an account maintained at the        Letter above.
Book-Entry Transfer Facility other than the account indicated
above.                                                          Mail:  New Notes and/or Old Notes to:

Issue:  New Notes and/or Old Notes to:                          Name(s).................................................
                                                                                 (Please Type or Print)
Name(s)..............................................
               (Please Type or Print)                           ........................................................
                                                                                 (Please Type or Print)
 .....................................................
               (Please Type or Print)                           Address.................................................

Address..............................................           ........................................................
                                                                                       (Zip Code)
 .....................................................
                     (Zip Code)


- -------------------------------------------------------       
Employer Identification or Social Security Number....

Credit unexchanged Old Notes delivered by book-entry
transfer to the Book-Entry Transfer Facility account set
                    forth below.

 .....................................................
            (Book-Entry Transfer Facility
           Account Number, if applicable)

- -------------------------------------------------------       ------------------------------------------------------------
</TABLE>

- --------------------------------------------------------------------------------

                        SPECIAL REGISTRATION INSTRUCTIONS


                             (See Paragraph 4 above)

     To be completed ONLY IF (i) the undersigned satisfies the conditions set
forth in paragraph 4 above, (ii) the undersigned elects to register its Old
Notes in the shelf registration described in the Registration Agreement, and
(iii) the undersigned agrees to comply with the Registration Agreement and to
indemnify certain entities and individuals as set forth in paragraph 4 above.

     [ ] By checking this box the undersigned hereby (i) represents that it is
entitled to have its Old Notes registered in a shelf registration in accordance
with the Registration Agreement, (ii) elects to have its Old Notes registered
pursuant to the shelf registration described in the Registration Agreement, and
(iii) agrees to comply with the Registration Agreement and to indemnify certain
entities and individuals identified in, and to the extent provided in, paragraph
4 above.

- --------------------------------------------------------------------------------

<PAGE>

     IMPORTANT: THIS LETTER OR A FACSIMILE HEREOF (TOGETHER WITH THE
CERTIFICATES FOR OLD NOTES OR A BOOK-ENTRY CONFIRMATION AND ALL OTHER REQUIRED
DOCUMENTS OR THE NOTICE OF GUARANTEED DELIVERY) MUST BE RECEIVED BY THE EXCHANGE
AGENT PRIOR TO 12:00 MIDNIGHT NEW YORK CITY TIME, ON THE EXPIRATION DATE.

                  PLEASE READ THIS ENTIRE LETTER OF TRANSMITTAL
                   CAREFULLY BEFORE COMPLETING ANY BOX ABOVE.

- --------------------------------------------------------------------------------

                               PLEASE SIGN HERE

                   (TO BE COMPLETED BY ALL TENDERING HOLDERS)

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

                    Signature(s) of Owner                      Date

     Area Code and Telephone Number  . . . . . . . . . . . . . . . .

     If a holder is tendering any Old Notes, this Letter must be signed by the
registered holder(s) as the name(s) appear(s) on the certificate(s) for the Old
Notes or by any person(s) authorized to become registered holder(s) by
endorsements and documents transmitted herewith. If signature is by a trustee,
executor, administrator, guardian, officer or other person acting in a fiduciary
or representative capacity, please set forth full title. See Instruction 3.

     Name(s): ..................................................................

     ...........................................................................
                             (Please Type or Print)

     Capacity: .................................................................

     Address:  .................................................................

     ...........................................................................
                              (Including Zip Code)

     Employer Identification or 
     Social Security Number ....................................................
                            (Please complete Substitute Form W-9, if applicable.
                            See "Important Tax Information" below)

                             SIGNATURE GUARANTEE (if
                           required by Instruction 3)


Signature(s) Guaranteed by
an Eligible Institution:  ......................................................
                             (Authorized Signature)

 ................................................................................
                                     (Title)

 ................................................................................
                                 (Name and Firm)

- --------------------------------------------------------------------------------

<PAGE>

INSTRUCTIONS
 
     1. Delivery of this Letter and Notes; Guaranteed Delivery Procedures.  This
Letter is to be completed by holders of Old Notes either if certificates are to
be forwarded herewith or if tenders are to be made pursuant to the procedures
for delivery by book-entry transfer set forth in 'The Exchange
Offers--Book-Entry Transfer' section of the Prospectus. Certificates for all
physically tendered Old Notes, or Book-Entry Confirmation, as the case may be,
as well as a properly completed and duly executed Letter (or manually signed
facsimile thereof), with any required signature guarantees, and any other
documents required by this Letter, must be received by the Exchange Agent at the
address set forth herein on or prior to the Expiration Date, or the tendering
holder must comply with the guaranteed delivery procedures set forth below. Old
Notes tendered hereby must be in denominations of principal amount at maturity
of $1,000 or any integral multiple thereof.
 
     Noteholders whose certificates for Old Notes are not immediately available
or who cannot deliver their certificates and all other required documents to the
Exchange Agent on or prior to the Expiration Date, or who cannot complete the
procedure for book-entry transfer on a timely basis, may tender their Old Notes
pursuant to the guaranteed delivery procedures set forth in 'The Exchange
Offers--Guaranteed Delivery Procedures' section of the Prospectus. Pursuant to
such procedures, (i) such tender must be made through an Eligible Institution
(as defined below), (ii) on or prior to 12:00 midnight, New York City time, on
the Expiration Date, the Exchange Agent must receive from such Eligible
Institution a properly completed and duly executed Letter (or a facsimile
thereof) and Notice of Guaranteed Delivery, substantially in the form provided
by the Company (by facsimile transmission, mail or hand delivery), setting forth
the name and address of the holder of Old Notes and the amount of Old Notes
tendered, stating that the tender is being made thereby and guaranteeing that
within three New York Stock Exchange ('NYSE') trading days after the date of
execution of the Notice of Guaranteed Delivery, the certificates for all
physically tendered Old Notes, in proper form for transfer, or a Book-Entry
Confirmation, as the case may be, and any other documents required by this
Letter will be deposited by the Eligible Institution with the Exchange Agent,
and (iii) the certificates for all physically tendered Old Notes, in proper form
for transfer, or Book-Entry Confirmation, as the case may be, and all other
documents required by this Letter, must be received by the Exchange Agent within
three NYSE trading days after the date of execution of the Notice of Guaranteed
Delivery.
 
     THE METHOD OF DELIVERY OF THIS LETTER, THE OLD NOTES AND ALL OTHER REQUIRED
DOCUMENTS IS AT THE ELECTION AND RISK OF THE TENDERING HOLDERS, BUT THE DELIVERY
WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED OR CONFIRMED BY THE EXCHANGE
AGENT. INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE. IN ALL CASES, SUFFICIENT TIMES SHOULD BE
ALLOWED TO ASSURE DELIVERY TO THE EXCHANGE AGENT PRIOR TO 12:00 MIDNIGHT, NEW
YORK CITY TIME, ON THE EXPIRATION DATE. NO LETTER OF TRANSMITTAL OR OLD NOTES
SHOULD BE SENT TO THE COMPANY.
 
     See 'The Exchange Offers' section in the Prospectus.
 

     2. Partial Tenders.  If less than all of the Old Notes evidenced by a
submitted certificate are to be tendered, the tendering holder(s) should fill in
the aggregate principal amount at maturity of Old Notes to be tendered in the
box above entitled 'Description of Old Notes--Principal Amount at Maturity
Tendered.' A reissued certificate representing the balance of nontendered Old
Notes of a tendering holder who physically delivered Old Notes will be sent to
such tendering holder, unless otherwise provided in the appropriate box on this
Letter, promptly after the Expiration Date. All of the Old Notes delivered to
the Exchange Agent will be deemed to have been tendered unless otherwise
indicated.
 
     3. Signatures on this Letter; Bond Powers and Endorsements; Guarantee of
Signatures.  If this Letter is signed by the registered holder of the Old Notes
tendered hereby, the signature must correspond exactly with the name as written
on the face of the certificates without any change whatsoever.
 
     If any tendered Old Notes are owned of record by two or more joint owners,
all such owners must sign this Letter.
 
     If any tendered Old Notes are registered in different names on several
certificates, it will be necessary to complete, sign and submit as many separate
copies of this Letter as there are different registrations of certificates.
 
     When this Letter is signed by the registered holder or holders of the Old
Notes specified herein and tendered hereby, no endorsements of certificates or
separate bond powers are required. If, however, the New Notes are to be issued,
or any untendered Old Notes are to be reissued, to a person other than the
registered holder, then endorsements of any certificates transmitted hereby or
separate bond powers are required. Signatures on such certificate(s) or bond
powers must be guaranteed by an Eligible Institution.
 
     If this Letter is signed by a person other than the registered holder or
holders of any certificate(s) specified herein, such certificates must be
endorsed or accompanied by appropriate bond powers, in either case signed
exactly as the name or names of the registered holder or holders appear(s) on
the certificate(s) and signatures on such certificate(s) or bond powers must be
guaranteed by an Eligible Institution.
 
     If this Letter or any certificates or bond powers are signed by trustees,
executors, administrators, guardians, attorneys-in-fact, officers of
corporations or others acting in a fiduciary or representative capacity, such
persons should so indicate when

<PAGE>

signing, and, unless waived by the Company, proper evidence satisfactory to the
Company of their authority to so act must be submitted with this Letter.
 
     Endorsements on certificates for Old Notes or signatures on bond power s
required by this Instruction 3 must be guaranteed by a financial institution
(including most banks, savings and loan associations and brokerage houses) that
is a participant in the Securities Transfer Agents Medallion Program (each an
'Eligible Institution' and collectively, 'Eligible Institutions').
 

     Signatures on the Letter need not be guaranteed by an Eligible Institution
if (A) the Old Notes are tendered (i) by a registered holder of Old Notes (which
term, for purposes of the Exchange Offer, includes any participant in the
Book-Entry Transfer Facility system whose name appears on a security position
listing as the holder of such Old Notes) who has not completed the box entitled
'Special Issuance Instructions' or 'Special Delivery Instructions' on this
Letter, or (ii) for the account of an Eligible Institution and (B) the box
entitled 'Special Registration Instructions' on this Letter has not been
completed.
 
     4. Special Issuance and Delivery Instructions.  Tendering holders of Old
Notes should indicate in the applicable box the name and address to which New
Notes issued pursuant to the Exchange Offer and/or substitute certificates
evidencing Old Notes not exchanged are to be issued or sent, if different from
the name or address of the person signing this Letter. In the case of issuance
in a different name, the employer identification or social security number of
the person named must also be indicated. Noteholders tendering Old Notes by
book-entry transfer may request that Old Notes not exchanged be credited to such
account maintained at the Book-Entry Transfer Facility as such noteholder may
designate hereon. If no such instructions are given, such Old Notes not
exchanged will be returned to the name and address of the person signing this
Letter.
 
     5. Transfer Taxes.  The Company will pay all transfer taxes, if any,
applicable to the transfer of Old Notes to it or its order pursuant to the
Exchange Offer. If, however, New Notes and/or substitute Old Notes not exchanged
are to be delivered to, or are to be registered or issued in the name of, any
person other than the registered holder of the Old Notes tendered hereby, or if
tendered Old Notes are registered in the name of any person other than the
person signing this Letter, or if a transfer tax is imposed for any reason other
than the transfer of Old Notes to the Company or its order pursuant to the
Exchange Offer, the amount of any such transfer taxes (whether imposed on the
registered holder or any other persons) will be payable by the tendering holder.
If satisfactory evidence of payment of such taxes or exemption therefrom is not
submitted herewith, the amount of such transfer taxes will be billed directly to
such tendering holder.
 
     Except as provided in this Instruction 5, it will not be necessary for
transfer tax stamps to be affixed to the Old Notes specified in this Letter.
 
     6. Waiver of Conditions.  The Company reserves the absolute right to waive
satisfaction of any or all conditions enumerated in the Prospectus.
 
     7. No Conditional Tenders.  No alternative, conditional, irregular or
contingent tenders will be accepted. All tendering holders of Old Notes, by
execution of this Letter, shall waive any right to receive notice of the
acceptance of their Old Notes for exchange.
 
     Although the Company intends to notify holders of defects or irregularities
with respect to tenders of Old Notes, neither the Company, the Exchange Agent
nor any other person shall incur any liability for failure to give any such
notice.
 
     8. Mutilated, Lost, Stolen or Destroyed Old Notes.  Any holder whose Old

Notes have been mutilated, lost, stolen or destroyed should contact the Exchange
Agent at the address indicated above for further instructions.
 
     9. Withdrawal of Tenders.  Tenders of Old Notes may be withdrawn at any
time prior to 12:00 midnight, New York City time, on the Expiration Date.
 
     For a withdrawal of a tender of Old Notes to be effective, a written or
facsimile transmission notice of withdrawal must be received by the Exchange
Agent at its address set forth above prior to 12:00 midnight, New York City
time, on the Expiration Date. Any such notice of withdrawal must (i) specify the
name of the person having deposited the Old Notes to be withdrawn (the
'Depositor'), (ii) identify the Old Notes to be withdrawn (including the
certificate number or numbers and principal amount of such Old Notes), (iii) be
signed by the holder in the same manner as the original signature on this Letter
by which such Old Notes were tendered (including any required signature
guarantees) or be accompanied by documents of transfer sufficient to have the
trustee under the Indenture pursuant to which the Old Notes were issued register
the transfer of such Old Notes into the name of the person withdrawing the
tender, and (iv) specify the name in which any such Old Notes are to be
registered, if different from that of the Depositor. Any Old Notes so properly
withdrawn will be deemed not to have been validly tendered for exchange for
purposes of the Exchange Offer. Any Old Notes which have been tendered for
exchange but which are not exchanged for any reason will be returned to the
holder thereof without cost to such holder as soon as practicable after
withdrawal, rejection of tender, or termination of the Exchange Offer. Properly
withdrawn Old

<PAGE>

Notes may be retendered by following the procedures described above at any time
on or prior to 12:00 midnight, New York City time, on the Expiration Date.
 
     All questions as to the validity, form, eligibility (including time of
receipt), acceptance and withdrawal of tendered Old Notes will be determined by
the Company in its sole discretion, which determination will be final and
binding. The Company reserves the absolute right to reject any and all Old Notes
not properly tendered or any Old Notes the Company's acceptance of which would,
in the opinion of counsel for the Company, be unlawful. The Company also
reserves the right to waive any defects, irregularities, or conditions of tender
as to particular Old Notes. The Company's interpretation of the terms and
conditions of the Exchange Offer (including the instructions of this Letter)
will be final and binding on all parties.
 
     10. Requests for Assistance or Additional Copies.  Questions relating to
the procedure for tendering, as well as requests for additional copies of the
Prospectus, this Letter and other related documents may be directed to the
Exchange Agent, at the address and telephone number indicated above.
 
                           IMPORTANT TAX INFORMATION
 
     Under current federal income tax law, a holder of New Notes is required to
provide the Company (as payor) with such holder's correct taxpayer
identification number ('TIN') on Substitute Form W-9 or otherwise establish a
basis for exemption from backup withholding to prevent backup withholding on any

New Notes delivered pursuant to the Exchange Offer and any payments received in
respect of the New Notes. If a holder of New Notes is an individual, the TIN is
such holder's social security number. If the Company is not provided with the
correct taxpayer identification number, a holder of New Notes may be subject to
a $50 penalty imposed by the Internal Revenue Service. Accordingly, each
prospective holder of New Notes to be issued pursuant to Special Issuance
Instructions should complete the attached Substitute Form W-9. The Substitute
Form W-9 need not be completed if the box entitled Special Issuance Instructions
has not been completed.
 
     Certain holders of New Notes (including, among others, all corporation and
certain foreign individuals) are not subject to these backup withholding and
reporting requirements. Exempt prospective holders of New Notes should indicate
their exempt status on Substitute Form W-9. A foreign individual may qualify as
an exempt recipient by submitting to the Company, through the Exchange Agent, a
properly completed Internal Revenue Service Form W- 8 (which the Exchange Agent
will provide upon request) signed under penalty of perjury, attesting to the
holder's exempt status. See the enclosed Guidelines for Certification of
Taxpayer Identification Number on Substitute Form W-9 for additional
instructions.
 
     If backup withholding applies, the Company is required to withhold 31% of
any payment made to the holder of New Notes or other payee. Backup withholding
is not an additional federal income tax. Rather, the federal income tax
liability of persons subject to backup withholding will be reduced by the amount
of tax withheld. If withholding results in an overpayment of taxes, a refund may
be obtained from the Internal Revenue Service.
 
PURPOSE OF SUBSTITUTE FORM W-9
 
     To prevent backup withholding on any New Notes delivered pursuant to the
Exchange Offer and any payments received in respect of the New Notes, each
prospective holder of New Notes to be issued pursuant to Special Issuance
Instructions should provide the Company, through the Exchange Agent, with
either: (i) such prospective holder's correct TIN by completing the form below,
certifying that the TIN provided on Substitute Form W-9 is correct (or that such
prospective holder is awaiting a TIN) and that (A) such prospective holder has
not been notified by the Internal Revenue Service that he or she is subject to
backup withholding as a result of a failure to report all interest or dividends
or (B) the Internal Revenue Service has notified such prospective holder that he
or she is no longer subject to backup withholding; or (ii) an adequate basis for
exemption.
 
WHAT NUMBER TO GIVE THE EXCHANGE AGENT
 
     The prospective holder of New Notes to be issued pursuant to Special
Issuance Instructions is required to give the Exchange Agent the TIN (e.g.,
social security number or employer identification number) of the prospective
record owner of the New Notes. If the New Notes will be held in more than one
name or are not held in the name of the actual owner, consult the enclosed
Guidelines for Certification of Taxpayer Identification Number on Substitute
Form W-9 for additional guidance regarding which number to report.


<PAGE>

<TABLE>
<CAPTION>

- ------------------------------------------------------------------------------------------------------------------------------------

                                                   PAYOR'S NAME: ISP HOLDINGS INC.

- ------------------------------------------------------------------------------------------------------------------------------------

<S>                                 <C>                                                    <C>
SUBSTITUTE                          Part 1 -- PLEASE PROVIDE YOUR TIN IN
FORM W-9                            THE BOX AT RIGHT AND CERTIFY BY                          -------------------------------------
                                    SIGNING AND DATING BELOW                                        Social Security Number

Department of the Treasury
Internal Revenue Service                                                                   OR

                                                                                             -------------------------------------
                                                                                                 Employer Identification Number

Payor's Request for    
Taxpayer Identification             ----------------------------------------------------   -----------------------------------------
Number (TIN)                        
                                    Part 2-Certification-Under Penalties of                Part 3
                                    Perjury, I certify that:

                                    (1) The number shown on this form is my
                                    current taxpayer identification number (or I am 
                                    waiting for a number to be issued to me) and                         Awaiting TIN

                                    (2) I am not subject to backup withholding either
                                    because I have not been notified by the Internal
                                    Revenue Service (the "IRS") that I am subject to
                                    backup withholding as a result of a failure to
                                    report all interest or dividends, or the IRS has
                                    notified me that I am no longer subject to
                                    backup withholding.


                                    ------------------------------------------------------------------------------------------------

                                    Certificate Instructions--You must cross out item (2) in Part 2 above if you have been notified
                                    by the IRS that you are subject to backup withholding because of underreporting interest or
                                    dividends on your tax return. However, if after being notified by the IRS that you are subject
                                    to backup withholding you receive another notification from the IRS stating that you are no
                                    longer subject to backup withholding, do not cross out item (2).

                                    SIGNATURE                                                   DATE
                                             -------------------------------------------            ------------------------------

- ------------------------------------------------------------------------------------------------------------------------------------
</TABLE>


NOTE:     FAILURE BY A PROSPECTIVE HOLDER OF NEW NOTES TO BE ISSUED PURSUANT TO
          THE SPECIAL ISSUANCE INSTRUCTIONS ABOVE TO COMPLETE AND RETURN THIS
          FORM MAY RESULT IN BACKUP WITHHOLDING OF 31% OF THE NEW NOTES
          DELIVERED TO YOU PURSUANT TO THE EXCHANGE OFFER AND ANY PAYMENTS
          RECEIVED BY YOU IN RESPECT OF THE NEW NOTES. PLEASE REVIEW THE
          ENCLOSED GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
          NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.

      YOU MUST COMPLETE THE FOLLOWING CERTIFICATION IF YOU CHECKED THE BOX
                        IN PART 3 OF SUBSTITUTE FORM W-9

- --------------------------------------------------------------------------------

             CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER

     I certify under penalties of perjury that a taxpayer identification number
has not been issued to me, and either (a) I have mailed or delivered an
application to receive a taxpayer identification number to the appropriate
Internal Revenue Service Center or Social Security Administration Office, or
(b) I intend to mail or deliver such an application in the near future. I
understand that if I do not provide a taxpayer identification number within
sixty (60) days, 31% of all reportable payments made to me thereafter will be
withheld until I provide such a number.

- -------------------------------------------       ------------------------------
              Signature                                    Date

- --------------------------------------------------------------------------------



<PAGE>

                             LETTER OF TRANSMITTAL
                               ISP HOLDINGS INC.
                           OFFER FOR ALL OUTSTANDING
                          9 3/4% SENIOR NOTES DUE 2002
                                IN EXCHANGE FOR
                     SERIES B 9 3/4% SENIOR NOTES DUE 2002
             PURSUANT TO THE PROSPECTUS, DATED FEBRUARY    , 1997.

- -------------------------------------------------------------------------------
THE EXCHANGE OFFER WILL EXPIRE AT 12:00 MIDNIGHT NEW YORK CITY TIME, ON MARCH  
   , 1997, (THE 'EXPIRATION DATE'). TENDERS MAY BE WITHDRAWN PRIOR TO 12:00
MIDNIGHT, NEW YORK CITY TIME, ON THE EXPIRATION DATE.
- -------------------------------------------------------------------------------


<TABLE>
<S>                                       <C>                                     <C>
                                              The Bank of New York

By Registered or Certified Mail:          Facsimile Transmission Number:            By Hand/Overnight Delivery:
      The Bank of New York                  (Eligible Institutions and                  The Bank of New York
    101 Barclay Street - 7E                  Withdrawal Notices Only)                    101 Barclay Street
   New York, New York 10286                       (212) 571-3080                 Corporate Trust Services Window
 Attn: Reorganization Section                                                              Ground Level
                                               Confirm by Telephone:                  New York, New York 10286 
                                                  (212) 815-2742                    Attn: Reorganization Section
                                        
                                               For Information Call:
                                                  (212) 815-6333
</TABLE>

         DELIVERY OF THIS INSTRUMENT TO AN ADDRESS OTHER THAN AS SET FORTH
ABOVE, OR TRANSMISSION OF INSTRUCTIONS BY ELIGIBLE INSTITUTIONS VIA FACSIMILE
OTHER THAN AS SET FORTH ABOVE, WILL NOT CONSTITUTE A VALID DELIVERY.

     The undersigned acknowledges that he or she has received the Prospectus,
dated February   , 1997 (the 'Prospectus'), of ISP Holdings Inc., a Delaware
corporation (the 'Company'), and this Letter of Transmittal (the 'Letter'),
which together constitute the Company's offer (the 'Exchange Offer') to exchange
an aggregate principal amount at maturity of up to $199,871,000 of Series B
9 3/4% Senior Notes due 2002 (the 'New Notes') of the Company for a like
principal amount at maturity of the issued and outstanding 9 3/4% Senior Notes
due 2002 (the 'Old Notes') of the Company from the holders thereof.
 
     For each Old Note accepted for exchange, the holder of such Old Note will
receive a New Note having a principal amount at maturity equal to that of the
surrendered Old Note. Holders whose Old Notes are accepted for exchange will
receive accrued interest thereon to, but not including, the day of issuance of
such New Notes, such interest to be payable with the first interest payment on
the New Notes. Interest on the New Notes will accrue from their respective dates
of issuance. Holders of Old Notes accepted for exchange will be deemed to have
waived the right to receive any other payments or interest on the Old Notes. The

Company reserves the right, at any time or from time to time, to extend the
Exchange Offer at its discretion, in which event the term 'Expiration Date'
shall mean the latest time and date to which the Exchange Offer is extended. The
Company shall notify the holders of the Old Notes of any extension by means of a
press release or other public announcement prior to 9:00 A.M., New York City
time, on the next business day after the previously scheduled Expiration Date.

      This Letter is to be completed by a holder of Old Notes either if
certificates are to be forwarded herewith or if a tender of certificates for Old
Notes, if available, is to be made by book-entry transfer to the account
maintained by The Bank of New York (the 'Exchange Agent') at The Depository
Trust Company (the 'Book-Entry Transfer Facility') pursuant to the procedures
set forth in 'The Exchange Offers--Book-Entry Transfer' section of the
Prospectus. Holders of Old Notes whose certificates are not immediately
available, or who are unable to deliver their certificates or confirmation of
the book-entry tender of their Old Notes into the Exchange Agent's account at
the Book-Entry Transfer Facility (a 'Book-Entry Confirmation') and all other
documents required by this Letter to the Exchange Agent on or prior to the
Expiration Date, must tender their Old Notes according to the guaranteed
delivery procedures set forth in 'The Exchange Offers--Guaranteed Delivery
Procedures' section of the Prospectus. See Instruction 1. Delivery of documents
to the Book-Entry Transfer Facility does not constitute delivery to the Exchange
Agent.

         The undersigned has completed the appropriate boxes below and signed
this Letter to indicate the action the undersigned desires to take with respect
to the Exchange Offer.

         List below the Old Notes to which this Letter relates. If the space
provided below is inadequate, the certificate numbers and principal amount at
maturity of Old Notes should be listed on a separate signed schedule affixed
hereto.

<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------------------------------
            DESCRIPTION OF OLD NOTES                              1                  2                   3
- ---------------------------------------------------------------------------------------------------------------------
                                                                                  Aggregate
                                                                                  Principal           Principal
                                                                                  Amount at           Amount at
Name(s) and Address(es) of Registered Holder(s)              Certificate         Maturity of          Maturity
           (Please fill in, if blank)                          Number(s)*        Old Note(s)         Tendered**

- ---------------------------------------------------------------------------------------------------------------------
<S>                                                          <C>                 <C>                 <C>             


                                                              Total

- ---------------------------------------------------------------------------------------------------------------------
</TABLE>

*    Need not be completed if Old Notes are being tendered by book-entry

     transfer.

**   Unless otherwise indicated in this column, a holder will be deemed to have
     tendered ALL of the Old Notes represented by the Old Notes indicated in
     column 2. See Instruction 2. Old Notes tendered hereby must be in
     denominations of principal amount at maturity of $1,000 and any integral
     multiple thereof. See Instruction 1.

<PAGE>

/ /  CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED BY BOOK-ENTRY 
     TRANSFER MADE TO THE ACCOUNT MAINTAINED BY THE EXCHANGE AGENT WITH THE
     BOOK-ENTRY TRANSFER FACILITY AND COMPLETE THE FOLLOWING:

     Name of Tendering Institution ____________________________________________

     Account Number ________________  Transaction Code Number _________________

/ /  CHECK HERE IF TENDERED OLD NOTES ARE BEING DELIVERED PURSUANT TO A NOTICE
     OF GUARANTEED DELIVERY PREVIOUSLY SENT TO THE EXCHANGE AGENT AND COMPLETE
     THE FOLLOWING:

     Name(s) of Registered Holder(s) __________________________________________

     Window Ticket Number (if any) ____________________________________________

     Date of Execution of Notice of Guaranteed Delivery _______________________

     Name of Institution which guaranteed delivery ____________________________

     If Delivered by Book-Entry Transfer, Complete the Following:

     Account Number ________________  Transaction Code Number _________________

/ /  CHECK HERE IF YOU ARE A BROKER-DEALER AND WISH TO RECEIVE 10 ADDITIONAL
     COPIES OF THE PROSPECTUS AND 10 COPIES OF ANY AMENDMENTS OR SUPPLEMENTS
     THERETO.

Name: _________________________________________________________________________

Address: ______________________________________________________________________

         ______________________________________________________________________


<PAGE>

              PLEASE READ THE ACCOMPANYING INSTRUCTIONS CAREFULLY

Ladies and Gentlemen:

     1. Upon the terms and subject to the conditions of the Exchange Offer, 
the undersigned hereby tenders to the Company the aggregate principal amount 
at maturity of Old Notes indicated above. Subject to, and effective upon, the
acceptance for exchange of the Old Notes tendered hereby, the undersigned hereby
sells, assigns and transfers to, or upon the order of, the Company all right,
title and interest in and to such Old Notes as are being tendered hereby.

     2. The undersigned hereby represents and warrants that the undersigned 
has full power and authority to tender, sell, assign and transfer the Old Notes
tendered hereby and that the Company will acquire good and unencumbered title
thereto, free and clear of all liens, restrictions, charges and encumbrances and
not subject to any adverse claim when the same are accepted by the Company. The
undersigned hereby further represents that any New Notes acquired in exchange
for Old Notes tendered hereby will have been acquired in the ordinary course of
business of the person receiving such New Notes, whether or not such person is
the undersigned, that neither the holder of such Old Notes nor any such other
person is engaging in or intends to engage in a distribution of such New Notes,
that neither the holder of such Old Notes nor any such other person has an
arrangement or understanding with any person to participate in the distribution
of such New Notes and that neither the holder of such Old Notes nor any such
other person is an "affiliate," as defined in Rule 405 under the Securities Act
of 1933, as amended (the "Securities Act"), of the Company.

     3. The undersigned also acknowledges that the Exchange Offer is being 
made in reliance on an interpretation, made to third parties, by the staff of
the Securities and Exchange Commission (the "SEC") that the New Notes issued in
exchange for the Old Notes pursuant to the Exchange Offer may be offered for
resale, resold and otherwise transferred by holders thereof (other than any such
holder that is an "affiliate" of the Company within the meaning of Rule 405
under the Securities Act), without compliance with the registration and
prospectus delivery provisions of the Securities Act, provided that such New
Notes are acquired in the ordinary course of such holders' business, such
holders are not engaging in and do not intend to engage in the distribution of
such New Notes and such holders have no arrangements with any person to
participate in the distribution of such New Notes. If the undersigned is not a
broker-dealer, the undersigned represents that it is not engaged in, and does
not intend to engage in, a distribution of New Notes. If the undersigned is a
broker-dealer that will receive New Notes for its own account in exchange for
Old Notes that were acquired as a result of market-making activities or other
trading activities, it acknowledges that it will deliver a prospectus meeting
the requirements of the Securities Act in connection with any resales of such
New Notes. However, by so acknowledging and by delivering a prospectus, the
undersigned will not be deemed to admit that it is an "underwriter" within the
meaning of the Securities Act.

     4. The undersigned may, if, and only if, it would not receive freely
tradeable New Notes in the Exchange Offer or is not eligible to participate in
the Exchange Offer, elect to have its Old Notes registered in the shelf

registration described in the Registration Rights Agreement, dated as of October
18, 1996, between the Company and Bear, Stearns & Co. Inc. (the 'Registration
Agreement') in the form included in Exhibit 4.2 to the Registration Statement of
the Company, Registration No. 333-17827. Capitalized terms used in this
paragraph 4 and not otherwise defined herein shall have the meanings given them
in the Registration Agreement. Such election may be made by checking the box
under 'Special Registration Instructions' below. By making such election, the
undersigned agrees, as a holder of Old Notes participating in a Shelf
Registration, to comply with the Registration Agreement and to indemnify and
hold harmless the Initial Purchaser and each person, if any, who controls the
Initial Purchaser within the meaning of either Section 15 of the Securities Act
or Section 20 of the Securities Exchange Act of 1934, as amended (the 'Exchange
Act'), and the Company, each director and officer of the Company and each
person, if any, who controls the Company within the meaning of either such
Section, from and against any losses, claims, damages and liabilities or any
actions in respect thereof, to which the Initial Purchaser or any controlling
person of the Initial Purchaser, and the Company or any of its directors,
officers or controlling persons may become subject under the Securities Act, the
Exchange Act or otherwise, insofar as such losses, claims, damages, liabilities
or actions arise out of or are based upon any untrue statement or alleged untrue
statement of a material fact contained in the Registration Statement or
prospectus or in any amendment or supplement thereto or in any preliminary
prospectus relating to a Shelf Registration, or arise out of or are based upon
any omission or alleged omission to state therein a material fact necessary to
make the statements therein not misleading, but in each case only to the extent
that the untrue statement or alleged untrue statement or omission or alleged
omission was made in reliance upon and in conformity with written information
furnished to the Company by or on behalf of the undersigned specifically for
inclusion therein; and, shall reimburse, as incurred, the Company for any legal
or other expenses reasonably incurred by the Company or any director, officer or
controlling person thereof in connection with the investigation or defending or
preparing to defend against or appearing as a third-party witness in connection
with any loss, claim, damage, liability or action in respect thereof. Any such
indemnification shall be governed by the terms and subject to the conditions set
forth in the Registration Agreement, including, without limitation, the
provisions regarding notice, retention of counsel, contribution and payment of
expenses set forth therein. The above summary of the indemnification provisions
of the Registration Agreement is not intended to be exhaustive and is qualified
in its entirety by the Registration Agreement.

<PAGE>

     5. The undersigned will, upon request, execute and deliver any additional
documents deemed by the Company to be necessary or desirable to complete the
sale, assignment and transfer of the Old Notes tendered hereby. All authority
conferred or agreed to be conferred in this Letter and every obligation of the
undersigned hereunder shall be binding upon the successors, assigns, heirs,
executors, administrators, trustees in bankruptcy and legal representatives of
the undersigned and shall not be affected by, and shall survive, the death or
incapacity of the undersigned. This tender may be withdrawn only in accordance
with the procedures set forth in "The Exchange Offers-Withdrawal Rights" section
of the Prospectus. See Instruction 9.

     6. Unless otherwise indicated in the box entitled 'Special Issuance

Instructions' below, please issue the New Notes (and, if applicable, substitute
certificates representing Old Notes for any Old Notes not exchanged) in the name
of the undersigned or, in the case of a book-entry delivery of Old Notes, please
credit the account indicated above maintained at the Book-Entry Transfer
Facility. Similarly, unless otherwise indicated under the box entitled 'Special
Delivery Instructions' below, please send the New Notes (and, if applicable,
substitute certificates representing Old Notes for any Old Notes not exchanged)
to the undersigned at the address shown above in the box entitled 'Description
of Old Notes.'

     The undersigned acknowledges that the Exchange Offer is subject to the more
detailed terms set forth in the Prospectus and, in case of any conflict between
the terms of the Prospectus and this Letter, the Prospectus shall prevail.


<PAGE>

     THE UNDERSIGNED, BY COMPLETING THE BOX ENTITLED "DESCRIPTION OF OLD NOTES"
ABOVE AND SIGNING THIS LETTER, WILL BE DEEMED TO HAVE TENDERED THE OLD NOTES
AS SET FORTH IN SUCH BOX ABOVE.

<TABLE>
<S>                                                           <C>

- -------------------------------------------------------       ------------------------------------------------------------
            SPECIAL ISSUANCE INSTRUCTIONS                                     SPECIAL DELIVERY INSTRUCTIONS
             (See Instructions 3 and 4)                                        (See Instructions 3 and 4)

  To be completed ONLY if certificates for Old Notes not          To be completed ONLY if certificates for Old Notes not
exchanged and/or New Notes are to be issued in the name of      exchanged and/or New Notes are to be sent to someone other than
someone other than the person or persons whose signature(s)     the person or persons whose signature(s) appear(s) on this Letter
appear(s) on this Letter below, or if Old Notes delivered by    below or to such person or persons at an address other than
book-entry transfer which are not accepted for exchange are     shown in the box entitled "Description of Old Notes" on this
to be returned by credit to an account maintained at the        Letter above.
Book-Entry Transfer Facility other than the account indicated
above.                                                          Mail:  New Notes and/or Old Notes to:

Issue:  New Notes and/or Old Notes to:                          Name(s).................................................
                                                                                 (Please Type or Print)
Name(s)..............................................
               (Please Type or Print)                           ........................................................
                                                                                 (Please Type or Print)
 .....................................................
               (Please Type or Print)                           Address.................................................

Address..............................................           ........................................................

 .....................................................           ........................................................
                                                                                       (Zip Code)
 .....................................................
                     (Zip Code)

 .....................................................
 (Employer Identification or Social Security Number)

Credit unexchanged Old Notes delivered by book-entry
transfer to the Book-Entry Transfer Facility account set
                    forth below.

 .....................................................
            (Book-Entry Transfer Facility
           Account Number, if applicable)

- -------------------------------------------------------       ------------------------------------------------------------
</TABLE>

- --------------------------------------------------------------------------------

                        SPECIAL REGISTRATION INSTRUCTIONS


                             (See Paragraph 4 above)

     To be completed ONLY IF (i) the undersigned satisfies the conditions set
forth in paragraph 4 above, (ii) the undersigned elects to register its Old
Notes in the shelf registration described in the Registration Agreement, and
(iii) the undersigned agrees to comply with the Registration Agreement and to
indemnify certain entities and individuals as set forth in paragraph 4 above.

     / / By checking this box the undersigned hereby (i) represents that it is
entitled to have its Old Notes registered in a shelf registration in accordance
with the Registration Agreement, (ii) elects to have its Old Notes registered
pursuant to the shelf registration described in the Registration Agreement, and
(iii) agrees to comply with the Registration Agreement and to indemnify certain
entities and individuals identified in, and to the extent provided in, paragraph
4 above.

- --------------------------------------------------------------------------------


<PAGE>

     IMPORTANT: THIS LETTER OR A FACSIMILE HEREOF (TOGETHER WITH THE
CERTIFICATES FOR OLD NOTES OR A BOOK-ENTRY CONFIRMATION AND ALL OTHER REQUIRED
DOCUMENTS OR THE NOTICE OF GUARANTEED DELIVERY) MUST BE RECEIVED BY THE EXCHANGE
AGENT PRIOR TO 12:00 MIDNIGHT NEW YORK CITY TIME, ON THE EXPIRATION DATE.

                  PLEASE READ THIS ENTIRE LETTER OF TRANSMITTAL
                   CAREFULLY BEFORE COMPLETING ANY BOX ABOVE.

- --------------------------------------------------------------------------------

                               PLEASE SIGN HERE

                   (TO BE COMPLETED BY ALL TENDERING HOLDERS)

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

          x . . . . . . . . . . . . . . . . . . .     . . . . . . . . . . . 1997

                    Signature(s) of Owner                      Date

     Area Code and Telephone Number  . . . . . . . . . . . . . . . .

     If a holder is tendering any Old Notes, this Letter must be signed by the
registered holder(s) as the name(s) appear(s) on the certificate(s) for the Old
Notes or by any person(s) authorized to become registered holder(s) by
endorsements and documents transmitted herewith. If signature is by a trustee,
executor, administrator, guardian, officer or other person acting in a fiduciary
or representative capacity, please set forth full title. See Instruction 3.

     Name(s): ..................................................................

     ...........................................................................
                             (Please Type or Print)

     Capacity: .................................................................

     Address:  .................................................................

     ...........................................................................
                              (Including Zip Code)

     Employer Identification or 
     Social Security Number ....................................................
                            (Please complete Substitute Form W-9, if applicable.
                            See "Important Tax Information" below)

                             SIGNATURE GUARANTEE (if
                           required by Instruction 3)

Signature(s) Guaranteed by
an Eligible Institution:  ......................................................
                             (Authorized Signature)

 ................................................................................
                                     (Title)

 ................................................................................
                                 (Name and Firm)

- --------------------------------------------------------------------------------


<PAGE>
                                  INSTRUCTIONS
 
     1. Delivery of this Letter and Notes; Guaranteed Delivery Procedures.  This
Letter is to be completed by holders of Old Notes either if certificates are to
be forwarded herewith or if tenders are to be made pursuant to the procedures
for delivery by book-entry transfer set forth in 'The Exchange
Offers--Book-Entry Transfer' section of the Prospectus. Certificates for all
physically tendered Old Notes, or Book-Entry Confirmation, as the case may be,
as well as a properly completed and duly executed Letter (or manually signed
facsimile thereof), with any required signature guarantees, and any other
documents required by this Letter, must be received by the Exchange Agent at the
address set forth herein on or prior to the Expiration Date, or the tendering
holder must comply with the guaranteed delivery procedures set forth below. Old
Notes tendered hereby must be in denominations of principal amount at maturity
of $1,000 or any integral multiple thereof.
 
     Noteholders whose certificates for Old Notes are not immediately available
or who cannot deliver their certificates and all other required documents to the
Exchange Agent on or prior to the Expiration Date, or who cannot complete the
procedure for book-entry transfer on a timely basis, may tender their Old Notes
pursuant to the guaranteed delivery procedures set forth in 'The Exchange
Offers--Guaranteed Delivery Procedures' section of the Prospectus. Pursuant to
such procedures, (i) such tender must be made through an Eligible Institution
(as defined below), (ii) on or prior to 12:00 midnight, New York City time, on
the Expiration Date, the Exchange Agent must receive from such Eligible
Institution a properly completed and duly executed Letter (or a facsimile
thereof) and Notice of Guaranteed Delivery, substantially in the form provided
by the Company (by facsimile transmission, mail or hand delivery), setting forth
the name and address of the holder of Old Notes and the amount of Old Notes
tendered, stating that the tender is being made thereby and guaranteeing that
within three New York Stock Exchange ('NYSE') trading days after the date of
execution of the Notice of Guaranteed Delivery, the certificates for all
physically tendered Old Notes, in proper form for transfer, or a Book-Entry
Confirmation, as the case may be, and any other documents required by this
Letter will be deposited by the Eligible Institution with the Exchange Agent,
and (iii) the certificates for all physically tendered Old Notes, in proper form
for transfer, or Book-Entry Confirmation, as the case may be, and all other
documents required by this Letter, must be received by the Exchange Agent within
three NYSE trading days after the date of execution of the Notice of Guaranteed
Delivery.
 
     THE METHOD OF DELIVERY OF THIS LETTER, THE OLD NOTES AND ALL OTHER REQUIRED
DOCUMENTS IS AT THE ELECTION AND RISK OF THE TENDERING HOLDERS, BUT THE DELIVERY
WILL BE DEEMED MADE ONLY WHEN ACTUALLY RECEIVED OR CONFIRMED BY THE EXCHANGE
AGENT. INSTEAD OF DELIVERY BY MAIL, IT IS RECOMMENDED THAT HOLDERS USE AN
OVERNIGHT OR HAND DELIVERY SERVICE. IN ALL CASES, SUFFICIENT TIMES SHOULD BE
ALLOWED TO ASSURE DELIVERY TO THE EXCHANGE AGENT PRIOR TO 12:00 MIDNIGHT, NEW
YORK CITY TIME, ON THE EXPIRATION DATE. NO LETTER OF TRANSMITTAL OR OLD NOTES
SHOULD BE SENT TO THE COMPANY.
 
     See 'The Exchange Offers' section in the Prospectus.
 
     2. Partial Tenders.  If less than all of the Old Notes evidenced by a

submitted certificate are to be tendered, the tendering holder(s) should fill in
the aggregate principal amount at maturity of Old Notes to be tendered in the
box above entitled 'Description of Old Notes--Principal Amount at Maturity
Tendered.' A reissued certificate representing the balance of nontendered Old
Notes of a tendering holder who physically delivered Old Notes will be sent to
such tendering holder, unless otherwise provided in the appropriate box on this
Letter, promptly after the Expiration Date. All of the Old Notes delivered to
the Exchange Agent will be deemed to have been tendered unless otherwise
indicated.
 
     3. Signatures on this Letter; Bond Powers and Endorsements; Guarantee of
Signatures.  If this Letter is signed by the registered holder of the Old Notes
tendered hereby, the signature must correspond exactly with the name as written
on the face of the certificates without any change whatsoever.
 
     If any tendered Old Notes are owned of record by two or more joint owners,
all such owners must sign this Letter.
 
     If any tendered Old Notes are registered in different names on several
certificates, it will be necessary to complete, sign and submit as many separate
copies of this Letter as there are different registrations of certificates.
 

     When this Letter is signed by the registered holder or holders of the Old
Notes specified herein and tendered hereby, no endorsements of certificates or
separate bond powers are required. If, however, the New Notes are to be issued,
or any untendered Old Notes are to be reissued, to a person other than the
registered holder, then endorsements of any certificates transmitted hereby or
separate bond powers are required. Signatures on such certificate(s) or bond
powers must be guaranteed by an Eligible Institution.

     If this Letter is signed by a person other than the registered holder or
holders of any certificate(s) specified herein, such certificates must be
endorsed or accompanied by appropriate bond powers, in either case signed
exactly as the name or names of the registered holder or holders appear(s) on
the certificate(s) and signatures on such certificate(s) or bond powers must be
guaranteed by an Eligible Institution.
 
     If this Letter or any certificates or bond powers are signed by trustees,
executors, administrators, guardians, attorneys-in-fact, officers of
corporations or others acting in a fiduciary or representative capacity, such
persons should so indicate when

<PAGE>

signing, and, unless waived by the Company, proper evidence satisfactory to the
Company of their authority to so act must be submitted with this Letter.
 
     Endorsements on certificates for Old Notes or signatures on bond powers
required by this Instruction 3 must be guaranteed by a financial institution
(including most banks, savings and loan associations and brokerage houses) that
is a participant in the Securities Transfer Agents Medallion Program (each an
'Eligible Institution' and collectively, 'Eligible Institutions').
 

     Signatures on the Letter need not be guaranteed by an Eligible Institution
if (A) the Old Notes are tendered (i) by a registered holder of Old Notes (which
term, for purposes of the Exchange Offer, includes any participant in the
Book-Entry Transfer Facility system whose name appears on a security position
listing as the holder of such Old Notes) who has not completed the box entitled
'Special Issuance Instructions' or 'Special Delivery Instructions' on this
Letter, or (ii) for the account of an Eligible Institution and (B) the box
entitled 'Special Registration Instructions' on this Letter has not been
completed.
 
     4. Special Issuance and Delivery Instructions.  Tendering holders of Old
Notes should indicate in the applicable box the name and address to which New
Notes issued pursuant to the Exchange Offer and/or substitute certificates
evidencing Old Notes not exchanged are to be issued or sent, if different from
the name or address of the person signing this Letter. In the case of issuance
in a different name, the employer identification or social security number of
the person named must also be indicated. Noteholders tendering Old Notes by
book-entry transfer may request that Old Notes not exchanged be credited to such
account maintained at the Book-Entry Transfer Facility as such noteholder may
designate hereon. If no such instructions are given, such Old Notes not
exchanged will be returned to the name and address of the person signing this
Letter.
 
     5. Transfer Taxes.  The Company will pay all transfer taxes, if any,
applicable to the transfer of Old Notes to it or its order pursuant to the
Exchange Offer. If, however, New Notes and/or substitute Old Notes not exchanged
are to be delivered to, or are to be registered or issued in the name of, any
person other than the registered holder of the Old Notes tendered hereby, or if
tendered Old Notes are registered in the name of any person other than the
person signing this Letter, or if a transfer tax is imposed for any reason other
than the transfer of Old Notes to the Company or its order pursuant to the
Exchange Offer, the amount of any such transfer taxes (whether imposed on the
registered holder or any other persons) will be payable by the tendering holder.
If satisfactory evidence of payment of such taxes or exemption therefrom is not
submitted herewith, the amount of such transfer taxes will be billed directly to
such tendering holder.
 
     Except as provided in this Instruction 5, it will not be necessary for
transfer tax stamps to be affixed to the Old Notes specified in this Letter.
 
     6. Waiver of Conditions.  The Company reserves the absolute right to waive
satisfaction of any or all conditions enumerated in the Prospectus.
 
     7. No Conditional Tenders.  No alternative, conditional, irregular or
contingent tenders will be accepted. All tendering holders of Old Notes, by
execution of this Letter, shall waive any right to receive notice of the
acceptance of their Old Notes for exchange.
 
     Although the Company intends to notify holders of defects or irregularities
with respect to tenders of Old Notes, neither the Company, the Exchange Agent
nor any other person shall incur any liability for failure to give any such
notice.
 
     8. Mutilated, Lost, Stolen or Destroyed Old Notes.  Any holder whose Old

Notes have been mutilated, lost, stolen or destroyed should contact the Exchange
Agent at the address indicated above for further instructions.
 
     9. Withdrawal of Tenders.  Tenders of Old Notes may be withdrawn at any
time prior to 12:00 midnight, New York City time, on the Expiration Date.
 
     For a withdrawal of a tender of Old Notes to be effective, a written or
facsimile transmission notice of withdrawal must be received by the Exchange
Agent at its address set forth above prior to 12:00 midnight, New York City
time, on the Expiration Date. Any such notice of withdrawal must (i) specify the
name of the person having deposited the Old Notes to be withdrawn (the
'Depositor'), (ii) identify the Old Notes to be withdrawn (including the
certificate number or numbers and principal amount of such Old Notes), (iii) be
signed by the holder in the same manner as the original signature on this Letter
by which such Old Notes were tendered (including any required signature
guarantees) or be accompanied by documents of transfer sufficient to have the
trustee under the Indenture pursuant to which the Old Notes were issued register
the transfer of such Old Notes into the name of the person withdrawing the
tender, and (iv) specify the name in which any such Old Notes are to be
registered, if different from that of the Depositor. Any Old Notes so properly
withdrawn will be deemed not to have been validly tendered for exchange for
purposes of the Exchange Offer. Any Old Notes which have been tendered for
exchange but which are not exchanged for any reason will be returned to the
holder thereof without cost to such holder as soon as practicable after
withdrawal, rejection of tender, or termination of the Exchange Offer. Properly
withdrawn Old

<PAGE>

Notes may be retendered by following the procedures described above at any time
on or prior to 12:00 midnight, New York City time, on the Expiration Date.
 
     All questions as to the validity, form, eligibility (including time of
receipt), acceptance and withdrawal of tendered Old Notes will be determined by
the Company in its sole discretion, which determination will be final and
binding. The Company reserves the absolute right to reject any and all Old Notes
not properly tendered or any Old Notes the Company's acceptance of which would,
in the opinion of counsel for the Company, be unlawful. The Company also
reserves the right to waive any defects, irregularities, or conditions of tender
as to particular Old Notes. The Company's interpretation of the terms and
conditions of the Exchange Offer (including the instructions of this Letter)
will be final and binding on all parties.
 
     10. Requests for Assistance or Additional Copies.  Questions relating to
the procedure for tendering, as well as requests for additional copies of the
Prospectus, this Letter and other related documents may be directed to the
Exchange Agent, at the address and telephone number indicated above.
 
                           IMPORTANT TAX INFORMATION
 
     Under current federal income tax law, a holder of New Notes is required to
provide the Company (as payor) with such holder's correct taxpayer
identification number ('TIN') on Substitute Form W-9 or otherwise establish a
basis for exemption from backup withholding to prevent backup withholding on any

New Notes delivered pursuant to the Exchange Offer and any payments received in
respect of the New Notes. If a holder of New Notes is an individual, the TIN is
such holder's social security number. If the Company is not provided with the
correct taxpayer identification number, a holder of New Notes may be subject to
a $50 penalty imposed by the Internal Revenue Service. Accordingly, each
prospective holder of New Notes to be issued pursuant to Special Issuance
Instructions should complete the attached Substitute Form W-9. The Substitute
Form W-9 need not be completed if the box entitled Special Issuance Instructions
has not been completed.
 
     Certain holders of New Notes (including, among others, all corporation and
certain foreign individuals) are not subject to these backup withholding and
reporting requirements. Exempt prospective holders of New Notes should indicate
their exempt status on Substitute Form W-9. A foreign individual may qualify as
an exempt recipient by submitting to the Company, through the Exchange Agent, a
properly completed Internal Revenue Service Form W- 8 (which the Exchange Agent
will provide upon request) signed under penalty of perjury, attesting to the
holder's exempt status. See the enclosed Guidelines for Certification of
Taxpayer Identification Number on Substitute Form W-9 for additional
instructions.
 
     If backup withholding applies, the Company is required to withhold 31% of
any payment made to the holder of New Notes or other payee. Backup withholding
is not an additional federal income tax. Rather, the federal income tax
liability of persons subject to backup withholding will be reduced by the amount
of tax withheld. If withholding results in an overpayment of taxes, a refund may
be obtained from the Internal Revenue Service.
 
PURPOSE OF SUBSTITUTE FORM W-9
 
     To prevent backup withholding on any New Notes delivered pursuant to the
Exchange Offer and any payments received in respect of the New Notes, each
prospective holder of New Notes to be issued pursuant to Special Issuance
Instructions should provide the Company, through the Exchange Agent, with
either: (i) such prospective holder's correct TIN by completing the form below,
certifying that the TIN provided on Substitute Form W-9 is correct (or that such
prospective holder is awaiting a TIN) and that (A) such prospective holder has
not been notified by the Internal Revenue Service that he or she is subject to
backup withholding as a result of a failure to report all interest or dividends
or (B) the Internal Revenue Service has notified such prospective holder that he
or she is no longer subject to backup withholding; or (ii) an adequate basis for
exemption.
 
WHAT NUMBER TO GIVE THE EXCHANGE AGENT
 
     The prospective holder of New Notes to be issued pursuant to Special
Issuance Instructions is required to give the Exchange Agent the TIN (e.g.,
social security number or employer identification number) of the prospective
record owner of the New Notes. If the New Notes will be held in more than one
name or are not held in the name of the actual owner, consult the enclosed
Guidelines for Certification of Taxpayer Identification Number on Substitute
Form W-9 for additional guidance regarding which number to report.


<PAGE>

<TABLE>
<CAPTION>

- ------------------------------------------------------------------------------------------------------------------------------------

                                                   PAYOR'S NAME: ISP HOLDINGS INC.

- ------------------------------------------------------------------------------------------------------------------------------------

<S>                                 <C>                                                    <C>
SUBSTITUTE                          Part 1--PLEASE PROVIDE YOUR TIN IN
FORM W-9                            THE BOX AT RIGHT AND CERTIFY BY                          -------------------------------------
                                    SIGNING AND DATING BELOW                                        Social Security Number

Department of the Treasury
Internal Revenue Service                                                                   OR

                                                                                             -------------------------------------
                                                                                                 Employer Identification Number

Payor's Request for    
Taxpayer Identification             ------------------------------------------------------------------------------------------------
Number (TIN)                        
                                    Part 2--Certification--Under Penalties of Perjury, I certify that:

                                    (1) The number shown on this form is my current taxpayer identification number (or I am
                                        waiting for a number to be issued to me) and                         

                                    (2) I am not subject to backup withholding either because I have not been notified by the 
                                        Internal Revenue Service (the "IRS") that I am subject to backup withholding as a result 
                                        of a failure to report all interest or dividends, or the IRS has notified me that I am 
                                        no longer subject to backup withholding.

<S>                                  <C>
                                    ------------------------------------------------------------------------------------------------

                                    Certificate Instructions--You must cross out item (2) in Part 2 above if you have been notified
                                    by the IRS that you are subject to backup withholding because of underreporting interest or
                                    dividends on your tax return. However, if after being notified by the IRS that you are subject
                                    to backup withholding you receive another notification from the IRS stating that you are no
                                    longer subject to backup withholding, do not cross out item (2).

                                    SIGNATURE                                                   DATE
                                             -------------------------------------------           -------------------------------
                                    ------------------------------------------------------------------------------------------------
                                    Part 3--Awaiting TIN / /
- ------------------------------------------------------------------------------------------------------------------------------------
</TABLE>

NOTE:     FAILURE BY A PROSPECTIVE HOLDER OF NEW NOTES TO BE ISSUED PURSUANT TO
          THE SPECIAL ISSUANCE INSTRUCTIONS ABOVE TO COMPLETE AND RETURN THIS
          FORM MAY RESULT IN BACKUP WITHHOLDING OF 31% OF THE NEW NOTES

          DELIVERED TO YOU PURSUANT TO THE EXCHANGE OFFER AND ANY PAYMENTS
          RECEIVED BY YOU IN RESPECT OF THE NEW NOTES. PLEASE REVIEW THE
          ENCLOSED GUIDELINES FOR CERTIFICATION OF TAXPAYER IDENTIFICATION
          NUMBER ON SUBSTITUTE FORM W-9 FOR ADDITIONAL DETAILS.

      YOU MUST COMPLETE THE FOLLOWING CERTIFICATION IF YOU CHECKED THE BOX
                        IN PART 3 OF SUBSTITUTE FORM W-9

- --------------------------------------------------------------------------------

             CERTIFICATE OF AWAITING TAXPAYER IDENTIFICATION NUMBER

     I certify under penalties of perjury that a taxpayer identification number
has not been issued to me, and either (a) I have mailed or delivered an
application to receive a taxpayer identification number to the appropriate
Internal Revenue Service Center or Social Security Administration Office, or
(b) I intend to mail or deliver such an application in the near future. I
understand that if I do not provide a taxpayer identification number within
sixty (60) days, 31% of all reportable payments made to me thereafter will be
withheld until I provide such a number.

                                                                       
- -------------------------------------------       ------------------------------
              Signature                                       Date

- --------------------------------------------------------------------------------



<PAGE>

                         NOTICE OF GUARANTEED DELIVERY
                                 FOR TENDER OF
                            9% SENIOR NOTES DUE 2003
                      (INCLUDING THOSE IN BOOK-ENTRY FORM)
                                       OF

                               ISP HOLDINGS INC.

     This form or one substantially equivalent hereto must be used to accept the
Exchange Offer relating to the tender of 9% Senior Notes due 2003 (the 'Old
Notes') of ISP Holdings Inc. (the 'Company') made pursuant to the Prospectus,
dated February   , 1997 (the 'Prospectus'), if certificates for Old Notes of the
Company are not immediately available or if the procedure for book-entry
transfer cannot be completed on a timely basis or time will not permit all
required documents to reach the Exchange Agent prior to 12:00 midnight, New York
City time, on March   , 1997 (the 'Expiration Date'). Such form may be delivered
or transmitted by facsimile transmission, mail or hand delivery to The Bank of
New York (the 'Exchange Agent') as set forth below. In addition, in order to
utilize the guaranteed delivery procedure to tender Old Notes pursuant to the
Exchange Offer, the Exchange Agent must receive from an Eligible Institution
prior to 12:00 midnight, New York City time, on the Expiration Date, a
completed, signed and dated Letter of Transmittal relating to the Old Notes (or
facsimile thereof). Capitalized terms used herein and not defined herein are
used as so defined in the Prospectus.

<TABLE>
<CAPTION>
                                               The Bank of New York

<S>                                       <C>                                 <C>
By Registered or Certified Mail:           Facsimile Transmission Number:         By Hand/Overnight Delivery:
         The Bank of New York             (For Eligible Institutions Only)            The Bank of New York        
         101 Barclay Street-7E                     (212) 571-3080                      101 Barclay Street         
       New York, New York 10286                                                  Corporate Trust Services Window  
     Attn:  Reorganization Section             Confirm by Telephone:                      Ground Level            
                                                   (212) 815-2742                   New York, New York 10286      
                                                                                  Attn:  Reorganization Section   
                                                For Information Call:
                                                  (212) 815-6333
</TABLE>

                                  ----------

         DELIVERY OF THIS NOTICE TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE, OR
TRANSMISSION OF THIS NOTICE VIA FACSIMILE OTHER THAN AS SET FORTH ABOVE, WILL
NOT CONSTITUTE A VALID DELIVERY.

<PAGE>
Ladies and Gentlemen:

     The undersigned hereby tenders to ISP Holdings Inc., a Delaware corporation
(the 'Company'), in accordance with the Company's offer, upon the terms and
subject to the conditions set forth in the Prospectus dated February   , 1997
(the 'Prospectus'), and in the accompanying Letter of Transmittal, receipt of
which is hereby acknowledged, $                           in aggregate principal
amount of Old Notes pursuant to the guaranteed delivery procedures described in
the Prospectus.

Name(s) of Record Holder(s)
                           -----------------------------------------------------
                                          (Please Type or Print)

Address
       -------------------------------------------------------------------------

       -------------------------------------------------------------------------

Area Code & Telephone No.
                         -------------------------------------------------------

Certificate Number(s) for
Old Notes (if available)
                        --------------------------------------------------------

Total Principal Amount
Represented by Certificate(s): $
                                ------------------------------------------------

- --------------------------------------------------------------------------------
         All authority herein conferred or agreed to be conferred shall survive
the death or incapacity of the undersigned and every obligation of the
undersigned hereunder shall be binding upon the heirs, personal representatives,
successors and assigns of the undersigned.
- --------------------------------------------------------------------------------

Signature of Holder(s)                                   Dated:
                      ----------------------------------       -----------------

                                                         Dated:
                      ----------------------------------       -----------------


         Must be signed by the holder(s) of the Old Notes as their name(s)
appear(s) on certificates for Old Notes or on a security position listing, or by
person(s) authorized to become registered holder(s) by endorsement and documents
transmitted with this Notice of Guaranteed Delivery. If signature is by a
trustee, executor, administrator, guardian, attorney-in-fact, officer or other
person acting in a fiduciary or representative capacity, such person must set
forth his or her full title below.


<PAGE>

                      Please print name(s) and address(es)

Name(s):
             -------------------------------------------------------------------

             -------------------------------------------------------------------

             -------------------------------------------------------------------

Capacity:
             -------------------------------------------------------------------

Address(es): 
             -------------------------------------------------------------------

             -------------------------------------------------------------------

             -------------------------------------------------------------------

/ /  The Depository Trust Company
     (Check if Old Notes will be tendered
     by book-entry transfer)

     Account Number
                    ---------------------------

              THE GUARANTEE ON THE FOLLOWING PAGE MUST BE COMPLETED



<PAGE>

                                    GUARANTEE

                    (Not to be used for signature guarantee)

         The undersigned, a financial institution (including most banks, savings
and loan associations and brokerage houses) that is a participant in the
Securities Transfer Agents Medallion Program, the New York Stock Exchange
Medallion Signature Program or the Stock Exchanges Medallion Program, hereby
guarantees that the undersigned will deliver to the Exchange Agent the
certificates representing the Old Notes being tendered hereby or confirmation of
book-entry transfer of such Old Notes into the Exchange Agent's account at The
Depository Trust Company, in proper form for transfer, together with any other
documents required by the Letter of Transmittal within three New York Stock
Exchange trading days after the Expiration Date.

         Name of Firm
                     -----------------------------------------------------------

         Address
                ----------------------------------------------------------------

                ----------------------------------------------------------------

         Area Code and Telephone No.
                                    --------------------------------------------

         Authorized Signature
                             ---------------------------------------------------

         Name
             -------------------------------------------------------------------
                                    (Please Type or Print)

         Title
              ------------------------------------------------------------------

         Dated
              ------------------------------------------------------------------

NOTE:    DO NOT SEND CERTIFICATES OF OLD NOTES WITH THIS FORM. CERTIFICATES OF
         OLD NOTES SHOULD BE SENT ONLY WITH A COPY OF THE PREVIOUSLY EXECUTED
         LETTER OF TRANSMITTAL.




<PAGE>

                         NOTICE OF GUARANTEED DELIVERY

                                 FOR TENDER OF
                          9 3/4% SENIOR NOTES DUE 2002
                      (INCLUDING THOSE IN BOOK-ENTRY FORM)
                                       OF
                               ISP HOLDINGS INC.

     This form or one substantially equivalent hereto must be used to accept the
Exchange Offer relating to the tender of 9 3/4% Senior Notes due 2002 (the 'Old
Notes') of ISP Holdings Inc. (the 'Company') made pursuant to the Prospectus,
dated February   , 1997 (the 'Prospectus'), if certificates for Old Notes of the
Company are not immediately available or if the procedure for book-entry
transfer cannot be completed on a timely basis or time will not permit all
required documents to reach the Exchange Agent prior to 12:00 midnight, New York
City time, on March   , 1997 (the 'Expiration Date'). Such form may be delivered
or transmitted by facsimile transmission, mail or hand delivery to The Bank of
New York (the 'Exchange Agent') as set forth below. In addition, in order to
utilize the guaranteed delivery procedure to tender Old Notes pursuant to the
Exchange Offer, the Exchange Agent must receive from an Eligible Institution
prior to 12:00 midnight, New York City time, on the Expiration Date, a
completed, signed and dated Letter of Transmittal relating to the Old Notes (or
facsimile thereof). Capitalized terms used herein and not defined herein are
used as so defined in the Prospectus.

<TABLE>
<CAPTION>
                                               The Bank of New York

<S>                                       <C>                                 <C>
By Registered or Certified Mail:           Facsimile Transmission Number:               By Hand/Overnight Delivery:
      The Bank of New York                (For Eligible Institutions Only)                  The Bank of New York
      101 Barclay Street-7E                        (212) 571-3080                            101 Barclay Street
    New York, New York 10286                                                           Corporate Trust Services Window
 Attn:  Reorganization Section                  Confirm by Telephone:                            Ground Level 
                                                   (212) 815-2742                          New York, New York 10286
                                                                                        Attn:  Reorganization Section
                                                For Information Call:
                                                    (212) 815-6333


                           ------------------------
</TABLE>


         DELIVERY OF THIS NOTICE TO AN ADDRESS OTHER THAN AS SET FORTH ABOVE, OR
TRANSMISSION OF THIS NOTICE VIA FACSIMILE OTHER THAN AS SET FORTH ABOVE, WILL
NOT CONSTITUTE A VALID DELIVERY.

<PAGE>
Ladies and Gentlemen:

     The undersigned hereby tenders to ISP Holdings Inc., a Delaware corporation
(the 'Company'), in accordance with the Company's offer, upon the terms and
subject to the conditions set forth in the Prospectus dated February   , 1997
(the 'Prospectus'), and in the accompanying Letter of Transmittal, receipt of
which is hereby acknowledged, $                           in aggregate principal
amount of Old Notes pursuant to the guaranteed delivery procedures described in
the Prospectus.

Name(s) of Record Holder(s)
                           -----------------------------------------------------
                                          (Please Type or Print)

Address
       -------------------------------------------------------------------------

       -------------------------------------------------------------------------

Area Code & Telephone No.
                         -------------------------------------------------------

Certificate Number(s) for
Old Notes (if available)
                        --------------------------------------------------------

Total Principal Amount
Represented by Certificate(s): $
                                ------------------------------------------------

- --------------------------------------------------------------------------------
         All authority herein conferred or agreed to be conferred shall survive
the death or incapacity of the undersigned and every obligation of the
undersigned hereunder shall be binding upon the heirs, personal representatives,
successors and assigns of the undersigned.
- --------------------------------------------------------------------------------

Signature of Holder(s)                                   Dated:
                      ----------------------------------       -----------------

                                                         Dated:
                      ----------------------------------       -----------------


         Must be signed by the holder(s) of the Old Notes as their name(s)
appear(s) on certificates for Old Notes or on a security position listing, or by
person(s) authorized to become registered holder(s) by endorsement and documents
transmitted with this Notice of Guaranteed Delivery. If signature is by a
trustee, executor, administrator, guardian, attorney-in-fact, officer or other
person acting in a fiduciary or representative capacity, such person must set
forth his or her full title below.



<PAGE>

                      Please print name(s) and address(es)

Name(s):
             -------------------------------------------------------------------

             -------------------------------------------------------------------

             -------------------------------------------------------------------

Capacity:
             -------------------------------------------------------------------

Address(es): 
             -------------------------------------------------------------------

             -------------------------------------------------------------------

             -------------------------------------------------------------------

/ /  The Depository Trust Company
     (Check if Old Notes will be tendered
     by book-entry transfer)

Account Number
              ---------------------------

              THE GUARANTEE ON THE FOLLOWING PAGE MUST BE COMPLETED



<PAGE>

                                    GUARANTEE

                    (Not to be used for signature guarantee)

         The undersigned, a financial institution (including most banks, savings
and loan associations and brokerage houses) that is a participant in the
Securities Transfer Agents Medallion Program, the New York Stock Exchange
Medallion Signature Program or the Stock Exchanges Medallion Program, hereby
guarantees that the undersigned will deliver to the Exchange Agent the
certificates representing the Old Notes being tendered hereby or confirmation of
book-entry transfer of such Old Notes into the Exchange Agent's account at The
Depository Trust Company, in proper form for transfer, together with any other
documents required by the Letter of Transmittal within three New York Stock
Exchange trading days after the Expiration Date.

         Name of Firm
                     -----------------------------------------------------------

         Address
                ----------------------------------------------------------------

                ----------------------------------------------------------------

         Area Code and Telephone No.
                                    --------------------------------------------

         Authorized Signature
                             ---------------------------------------------------

         Name
             -------------------------------------------------------------------
                                    (Please Type or Print)

         Title
              ------------------------------------------------------------------

         Dated
              ------------------------------------------------------------------

NOTE:    DO NOT SEND CERTIFICATES OF OLD NOTES WITH THIS FORM. CERTIFICATES OF
         OLD NOTES SHOULD BE SENT ONLY WITH A COPY OF THE PREVIOUSLY EXECUTED
         LETTER OF TRANSMITTAL.





<PAGE>
                                                                       EXH. 99.5
 
                                                                          , 1997
 
                            EXCHANGE AGENT AGREEMENT
 
The Bank of New York
Corporate Trust Trustee Administration
101 Barclay Street--21st Floor
New York, New York 10286
 
Ladies and Gentlemen:
 
     ISP Holdings Inc., a Delaware corporation (the 'Company'), proposes to make
offers (the 'Exchange Offers') to exchange (i) its 9% Senior Notes due 2003 (the
'Old 9% Notes') for its Series B 9% Senior Notes due 2003 (the 'New 9% Notes'),
and (ii) its 9 3/4 Senior Notes due 2002 (the 'Old 9 3/4 Notes', and together
with the Old 9% Notes, the 'Old Securities') for its Series B 9 3/4% Series
Notes due 2002 (the 'New 9 3/4% Notes', and together with the New 9% Notes, the
'New Securities'). The terms and conditions of the Exchange Offers as currently
contemplated are set forth in a Prospectus, dated                      , 1997
(the 'Prospectus'), proposed to be distributed to all of the record holders of
the Old Securities. The Old Securities and the New Securities are collectively
referred to herein as the 'Securities'.
 
     The Company hereby appoints The Bank of New York to act as exchange agent
(the 'Exchange Agent') in connection with the Exchange Offers. References
hereinafter to 'you' shall refer to The Bank of New York.
 
     Each Exchange Offer is expected to be commenced by the Company on or about
                     , 1997. The appropriate Letter of Transmittal accompanying
the Prospectus is to be used by holders of the Old Securities to accept the
applicable Exchange Offer, and contains instructions with respect to the
delivery of certificates for Old Securities tendered.
 
     Each Exchange Offer shall expire at 12 Midnight, New York City time, on
                     , 1997 or on such later date or time to which the Company
may extend the Exchange Offers (the 'Expiration Date'). Subject to the terms and
conditions set forth in the Prospectus, the Company expressly reserves the right
to extend either Exchange Offer from time to time and may extend such Exchange
Offer by giving oral (confirmed in writing) or written notice to you before 9:00
A.M., New York City time, on the business day following the previously scheduled
Expiration Date.
 
     The Company expressly reserves the right to amend or terminate the Exchange
Offers, and not to accept for exchange any Old Securities not theretofore
accepted for exchange, as specified in the Prospectus under the caption 'The
Exchange Offers--Expiration Date; Amendments.' The Company will give oral
(confirmed in writing) or written notice of any amendment, termination or
nonacceptance to you as promptly as practicable.
 
     In carrying out your duties as Exchange Agent, you are to act in accordance
with the following instructions:

 
     1. You will perform such duties and only such duties as are specifically
set forth in the section of the Prospectus captioned 'The Exchange Offers' or as
specifically set forth herein; provided, however, that in no way will your
general duty to act in good faith be discharged by the foregoing.
 
     2. You will establish separate accounts with respect to the Old Securities
at The Depository Trust Company (the 'Book-Entry Transfer Facility') for
purposes of each Exchange Offer within two business days after the date of the
Prospectus, and any financial institution that is a participant in the
Book-Entry Transfer Facility's systems may make book-entry delivery of the
applicable Old Securities by causing the Book-Entry Transfer Facility to
transfer such Old Securities into your applicable account in accordance with the
Book-Entry Transfer Facility's procedure for such transfer.
 
     3. You are to examine each of the Letters of Transmittal and certificates
for Old Securities (or confirmation of book-entry transfer into your account at
the Book-Entry Transfer Facility) and any other documents delivered or mailed to
you by or for holders of the Old Securities to ascertain whether: (i) the
Letters of Transmittal and any such other documents are duly executed and
properly completed in accordance with instructions set forth therein; and (ii)
the Old Securities have otherwise been properly tendered. You shall have no such
duty, however, with respect to any such document which you do not receive, other
than as a result of your own gross negligence or willful misconduct. In each
case where the Letter of Transmittal or any other document has been improperly

<PAGE>

completed or executed or any of the certificates for Old Securities are not in
proper form for transfer or some other irregularity in connection with the
acceptance of either Exchange Offer exists, you will endeavor to inform the
presenters of the need for fulfillment of all requirements and to take any other
action as may be necessary or advisable to cause such irregularity to be
corrected.
 
     4. With the approval of the Chief Executive Officer, any Senior Vice
President, any Executive Vice President, or any Vice President of the Company
(such approval, if given orally, to be confirmed in writing) or any other party
designated by such an officer in writing, you are authorized to waive any
irregularities in connection with any tender of Old Securities pursuant to the
Exchange Offers.
 
     5. Tenders of Old Securities may be made only as set forth in the Letter of
Transmittal and in the section of Prospectus captioned 'The Exchange
Offers--Procedures for Tendering' and Old Securities shall be considered
properly tendered to you only when tendered in accordance with the procedures
set forth therein.
 
     Notwithstanding the provisions of this paragraph 5, Old Securities which
the Chief Executive Officer, any Senior Vice President, any Executive Vice
President, or any Vice President of the Company shall approve as having been
properly tendered shall be considered to be properly tendered (such approval, if
given orally, shall be confirmed in writing).
 

     6. You shall advise the Company with respect to any Old Securities received
subsequent to the Expiration Date and accept its instructions with respect to
disposition of such Old Securities.
 
     7. You shall accept tenders:
 
          (a) in cases where the Old Securities are registered in two or more
     names only if signed by all named holders;
 
          (b) in cases where the signing person (as indicated on the Letter of
     Transmittal) is acting in a fiduciary or a representative capacity only
     when proper evidence of his or her authority so to act is submitted; and
 
          (c) from persons other than the registered holder of Old Securities
     provided that customary transfer requirements, including any applicable
     transfer taxes, are fulfilled.
 
     You shall accept partial tenders of Old Securities where so indicated and
as permitted in the Letter of Transmittal and deliver certificates for Old
Securities to the transfer agent for split-up and return any untendered Old
Securities to the holder (or such other person as may be designated in the
Letter of Transmittal) as promptly as practicable after expiration or
termination of the applicable Exchange Offer.
 
     8. Upon satisfaction or waiver of all of the conditions to the applicable
Exchange Offer, the Company will notify you (such notice if given orally, to be
confirmed in writing) of its acceptance, promptly after the Expiration Date, of
all Old Securities properly tendered and you, on behalf of the Company, will
exchange such Old Securities for New Securities and cause such Old Securities to
be cancelled. Delivery of New Securities will be made on behalf of the Company
by you at the rate of $1,000 principal amount of New Securities for each $1,000
principal amount of the corresponding series of Old Securities tendered promptly
after notice (such notice if given orally, to be confirmed in writing) of
acceptance of said Old Securities by the Company; provided, however, that in all
cases, Old Securities tendered pursuant to the Exchange Offers will be exchanged
only after timely receipt by you of certificates for such Old Securities (or
confirmation of book-entry transfer into your account at the Book-Entry Transfer
Facility), a properly completed and duly executed Letter of Transmittal (or a
facsimile thereof) with any required signature guarantees and any other required
documents. You shall issue New Securities only in denominations of $1,000 or any
integral multiple thereof.
 
     9. Tenders pursuant to the Exchange Offers are irrevocable, except that,
subject to the terms and upon the conditions set forth in the Prospectus and the
Letter of Transmittal, Old Securities tendered pursuant to the Exchange Offer
may be withdrawn at any time prior to the Expiration Date.
 
     10. The Company shall not be required to exchange any Old Securities
tendered if any of the conditions set forth in the Exchange Offers are not met.
Notice of any decision by the Company not to exchange any Old Securities
tendered shall be given (and confirmed in writing) by the Company to you.
 
                                       2
<PAGE>


     11. If, pursuant to the Exchange Offers, the Company does not accept for
exchange all or part of the Old Securities tendered because of an invalid
tender, the occurrence of certain other events set forth in the Prospectus under
the caption 'The Exchange Offers--Conditions' or otherwise, you shall as soon as
practicable after the expiration or termination of the applicable Exchange Offer
return those certificates for unaccepted Old Securities (or effect appropriate
book-entry transfer), together with any related required documents and the
Letters of Transmittal relating thereto that are in your possession, to the
persons who deposited them.
 
     12. All certificates for reissued Old Securities, unaccepted Old Securities
or for New Securities shall be forwarded by (a) first-class certified mail,
return receipt requested under a blanket surety bond protecting you and the
Company from loss or liability arising out of the non-receipt or non-delivery of
such certificates or (b) by registered mail insured separately for the
replacement value of each of such certificates.
 
     13. You are not authorized to pay or offer to pay any concessions,
commissions or solicitation fees to any broker, dealer, bank or other persons or
to engage or utilize any person to solicit tenders.
 
     14. As Exchange Agent hereunder you:
 
          (a) shall have no duties or obligations other than those specifically
     set forth herein or in the section of Prospectus captioned 'The Exchange
     Offers' or as may be subsequently agreed to in writing by you and the
     Company;
 
          (b) will be regarded as making no representations and having no
     responsibilities as to the validity, sufficiency, value or genuineness of
     any of the certificates or the Old Securities represented thereby deposited
     with you pursuant to the Exchange Offers, and will not be required to and
     will make no representation as to the validity, value or genuineness of the
     Exchange Offers; provided, however, that in no way will your general duty
     to act in good faith be discharged by the foregoing;
 
          (c) shall not be obligated to take any legal action hereunder which
     might in your reasonable judgment involve any expense or liability, unless
     you shall have been furnished with reasonable indemnity;
 
          (d) may reasonably rely on and shall be protected in acting in
     reliance upon any certificate, instrument, opinion, notice, letter,
     telegram or other document or security delivered to you and reasonably
     believed by you to be genuine and to have been signed by the proper party
     or parties;
 
          (e) may reasonably act upon any tender, statement, request, comment,
     agreement or other instrument whatsoever not only as to its due execution
     and validity and effectiveness of its provisions, but also as to the truth
     and accuracy of any information contained therein, which you shall in good
     faith believe to be genuine or to have been signed or represented by a
     proper person or persons;
 

          (f) may rely on and shall be protected in acting upon written or oral
     instructions from any officer of the Company;
 
          (g) may consult with your counsel with respect to any questions
     relating to your duties and responsibilities and the advice or opinion of
     such counsel shall be full and complete authorization and protection in
     respect of any action taken, suffered or omitted to be taken by you
     hereunder in good faith and in accordance with the advice or opinion of
     such counsel; and
 
          (h) shall not advise any person tendering Old Securities pursuant to
     either Exchange Offer as to the wisdom of making such tender or as to the
     market value or decline or appreciation in market value of any Old
     Securities or New Securities.
 
     15. You shall take such action as may from time to time be requested by the
Company or its counsel (and such other action as you may reasonably deem
appropriate) to furnish copies of the Prospectus, Letters of Transmittal and the
Notices of Guaranteed Delivery (as defined in the Prospectus) or such other
forms as may be approved from time to time by the Company, to all persons
requesting such documents and to accept and comply with telephone requests for
information relating to the Exchange Offers, provided that such information
shall relate only to the procedures for accepting (or withdrawing from) the
Exchange Offers. The Company will furnish you with copies of such documents at
your request. All other requests for information relating to the Exchange Offer
shall be directed to the Company, Attention: Investor Relations.
 
                                       3

<PAGE>

     16. You shall advise by facsimile transmission or telephone, and promptly
thereafter confirm in writing to Assistant Treasurer of the Company and such
other person or persons as it may request, daily (and more frequently during the
week immediately preceding the Expiration Date and if otherwise requested) up to
and including the Expiration Date, as to the number of Old Securities which have
been tendered pursuant to each Exchange Offer and the items received by you
pursuant to this Agreement, separately reporting and giving cumulative totals as
to items properly received and items improperly received. In addition, you will
also inform, and cooperate in making available to, the Company or any such other
person or persons upon oral request made from time to time prior to the
Expiration Date of such other information as it or he or she reasonably
requests. Such cooperation shall include, without limitation, the granting by
you to the Company and such person as the Company may request of access to those
persons on your staff who are responsible for receiving tenders, in order to
ensure that immediately prior to the Expiration Date of either Exchange Offer
the Company shall have received information in sufficient detail to enable it to
decide whether to extend the Exchange Offers. You shall prepare a final list of
all persons whose tenders were accepted, the aggregate principal amount of Old
Securities tendered and the aggregate principal amount of Old Securities
accepted, and deliver said list to the Company. Upon receipt of said list, the
Company will promptly provide you with a calculation of the principal amount of
New Securities to be issued to each holder.
 

     17. Letters of Transmittal and Notices of Guaranteed Delivery shall be
stamped by you as to the date and the time of receipt thereof and shall be
preserved by you for a period of time at least equal to the period of time you
preserve other records pertaining to the transfer of securities. You shall
dispose of unused Letters of Transmittal and other surplus materials by
returning them to the Company.
 
     18. You hereby expressly waive any lien, encumbrance or right of set-off
whatsoever that you may have with respect to funds deposited with you for the
payment of transfer taxes by reasons of amounts, if any, borrowed by the
Company, or any of its subsidiaries or affiliates pursuant to any loan or credit
agreement with you or for compensation owed to you hereunder.
 
     19. For services rendered as Exchange Agent hereunder, you shall be
entitled to such compensation as set forth on Schedule I attached hereto.
 
     20. You hereby acknowledge receipt of the Prospectus and each of the
Letters of Transmittal attached hereto and further acknowledge that you have
examined each of them. Any inconsistency between this Agreement, on the one
hand, and the Prospectus and the applicable Letter of Transmittal (as they may
be amended from time to time), on the other hand, shall be resolved in favor of
the latter two documents, except with respect to the duties, liabilities and
indemnification of you as Exchange Agent, which shall be controlled by this
Agreement.
 
     21. The Company covenants and agrees to indemnify and hold you harmless in
your capacity as Exchange Agent hereunder against any loss, liability, cost or
expense, including reasonable attorneys' fees and expenses, arising out of or in
connection with any act, omission, delay or refusal made by you in reliance upon
any signature, endorsement, assignment, certificate, order, request, notice,
instruction or other instrument or document reasonably believed by you to be
valid, genuine and sufficient and in accepting any tender or effecting any
transfer of Old Securities reasonably believed by you in good faith to be
authorized, and in delaying or refusing in good faith to accept any tenders or
effect any transfer of Old Securities; provided, however, that the Company shall
not be liable for indemnification or otherwise for any loss, liability, cost or
expense to the extent arising out of your gross negligence or willful
misconduct. In no case shall the Company be liable under this indemnity with
respect to any claim against you unless the Company shall be notified by you, by
letter or cable or by facsimile confirmed by letter, of the written assertion of
a claim against you or of any other action commenced against you, promptly after
you shall have received any such written assertion or commencement of action.
The Company shall be entitled to participate at its own expense in the defense
of any such claim or other action, and, if the Company so elects, the Company
shall assume the defense of any suit brought to enforce any such claim. In the
event that the Company shall assume the defense of any such suit, the Company
shall not be liable for the fees and expenses of any counsel thereafter incurred
by you so long as the Company shall retain counsel reasonably satisfactory to
you to defend such suit.
 
     22. You shall arrange to comply with all requirements under the tax laws of
the United States, including those relating to missing Taxpayer Identification
Numbers, and shall file any appropriate reports with the Internal Revenue
Service. The Company understands that you are required to deduct 31% on payments

to holders who
 
                                       4

<PAGE>

have not supplied their correct Taxpayer Identification Number or required
certification. Such funds will be turned over to the Internal Revenue Service in
accordance with applicable regulations.
 
     23. You shall deliver or cause to be delivered, in a timely manner to each
governmental authority to which any transfer taxes are payable in respect of the
exchange of Old Securities, your check in the amount of all transfer taxes so
payable, and the Company shall reimburse you for the amount of any and all
transfer taxes payable in respect of the exchange of Old Securities; provided,
however, that you shall reimburse the Company for amounts refunded to you in
respect of your payment of any such transfer taxes, at such time as such refund
is received by you and, provided further, that if New Securities and/or
substitute Old Securities not exchanged are to be delivered to, or are to be
registered or issued in the name of, any person other than the registered holder
of the Old Securities tendered in the Exchange Offers, or if tendered Old Notes
are registered in the name of any person other than the person signing the
applicable Letter of Transmittal, or if a transfer tax is imposed for any reason
other than the transfer of Old Securities to the Company or its order pursuant
to the Exchange Offers, the amount of any such transfer taxes (whether imposed
on the registered holder or any other persons) will be payable by the tendering
holder and will not be reimbursed to you by the Company. In no event, however,
will the Exchange Agent be responsible for the payment of any applicable
transfer tax imposed for any reason other than the exchange of Old Securities.
 
     24. This Agreement and your appointment as Exchange Agent hereunder shall
be construed and enforced in accordance with the laws of the State of New York
applicable to agreements made and to be performed entirely within such state,
and without regard to conflicts of law principles, and shall inure to the
benefit of, and the obligations created hereby shall be binding upon, the
successors and assigns of each of the parties hereto.
 
     25. This Agreement may be executed in two or more counterparts, each of
which shall be deemed to be an original and all of which taken together shall
constitute one and the same agreement.
 
     26. In case any provision of this Agreement shall be invalid, illegal or
unenforceable, the validity, legality and enforceability of the remaining
provisions shall not in any way be affected or impaired thereby.
 
     27. This Agreement shall not be deemed or construed to be modified,
amended, rescinded, cancelled or waived, in whole or in part, except by a
written instrument signed by a duly authorized representative of the party to be
charged. This Agreement may not be modified orally.
 
     28. Unless otherwise provided herein, all notices, requests and other
communications to any party hereunder shall be in writing (including facsimile
or similar writing) and shall be given to such party, addressed to it, at its
address or telecopy number set forth below:

 
         If to the Company:
 
           ISP Holdings Inc.
           c/o ISP Management Company, Inc.
           1361 Alps Road
           Wayne, New Jersey 07470
 
           Facsimile: (201) 628-4090
           Attention: Senior Vice President--Finance
 
         If to the Exchange Agent:
 
           The Bank of New York
           101 Barclay Street
           Floor 21 West
           New York, New York 10286
 
           Facsimile: (212) 815-5915
           Attention: Corporate Trust Trustee
                      Administration
 
     29. Unless terminated earlier by the parties hereto, this Agreement shall
terminate after all obligations of the parties hereunder shall have been
fulfilled. Notwithstanding the foregoing, Paragraphs 19, 21 and 23 shall survive
 
                                       5

<PAGE>

the termination of this Agreement. Upon any termination of this Agreement, you
shall promptly deliver to the Company any certificates for Securities, funds or
property then held by you as Exchange Agent under this Agreement.
 
     30. This Agreement shall be binding and effective as of the date hereof.
 
     Please acknowledge receipt of this Agreement and confirm the arrangements
herein provided by signing and returning the enclosed copy.
 
                                          ISP HOLDINGS INC.



                                          By: __________________________________
                                              Name:
                                              Title:
 
Accepted as the date
first above written:
 
THE BANK OF NEW YORK, as Exchange Agent




 
By: __________________________________
    Name:
    Title:

 
                                       6
<PAGE>
                                   SCHEDULE I
 

                                       7



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