IRON MOUNTAIN INC /DE, DEF 14A, 1998-04-23

IRON MOUNTAIN INC /DE
DEF 14A, 1998-04-23
PUBLIC WAREHOUSING & STORAGE

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SCHEDULE 14A
(Rule 14a-101)
INFORMATION REQUIRED IN PROXY STATEMENT
SCHEDULE 14A INFORMATION
Proxy Statement Pursuant to Section 14(a) of the Securities
Exchange Act of 1934 (Amendment No. )

Filed by the Registrant [X]
Filed by a Party other than the Registrant [ ]
Check the appropriate box:
[ ] Preliminary Proxy Statement
[X] Definitive Proxy Statement
[ ] Confidential, for Use of the Commission Only (as permitted by
Rule 14a-6(e)(2))
[ ] Definitive Additional Materials
[ ] Soliciting Material Pursuant to Rule 14a-11(c) or Rule 14a-12

Iron Mountain Incorporated
------------------------------------------------------------------------
(Name of Registrant as Specified In Its Charter)

------------------------------------------------------------------------
(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

Payment of Filing Fee (Check the appropriate box):
[X] No Fee Required.
[ ] Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

1) Title of each class of Securities to which transaction applies:

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2) Aggregate number of securities to which transaction applies:

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3) Per unit price or other underlying value of transaction computed
pursuant to Exchange Act Rule 0-11 (set forth the amount on which
the filing fee is calculated and state how it was determined):

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4) Proposed maximum aggregate value of transaction:

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5) Total fee paid:

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[ ] Fee paid previously with preliminary materials.
[ ] Check box if any part of the fee is offset as provided by Exchange Act Rule
0-11(a)(2) and identify the filing for which the offsetting fee was paid
previously. Identify the previous filing by registration statement number,
or the Form or Schedule and the date of its filing.

1) Amount Previously Paid:

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2) Form, Schedule or Registration Statement No.:

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3) Filing Party:

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4) Date Filed:

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<PAGE>

IRON MOUNTAIN INCORPORATED
745 Atlantic Avenue
Boston, Massachusetts 02111

NOTICE OF 1998 ANNUAL MEETING OF STOCKHOLDERS
TO BE HELD ON MAY 28, 1998

To the Stockholders of
IRON MOUNTAIN INCORPORATED:

The 1998 Annual Meeting of Stockholders of Iron Mountain Incorporated, a
Delaware corporation ("Iron Mountain" or the "Company"), will be held at the
offices of Sullivan & Worcester LLP, 23rd Floor, One Post Office Square,
Boston, Massachusetts, on May 28, 1998 at 9:30 a.m., local time, for the
following purposes:

1. To elect three Class C Directors for a three-year term or until their
successors are elected and qualified;

2. To approve the adoption of the Iron Mountain Incorporated 1998
Employee Stock Purchase Plan;

3. To approve an amendment to the Iron Mountain Incorporated 1995 Stock
Incentive Plan to increase the number of shares of Common Stock
authorized for issuance thereunder from 1,400,000 to 2,000,000;

4. To approve an amendment to the Iron Mountain Incorporated 1995 Stock
Incentive Plan to increase the total number of shares of Common Stock
with respect to which options and Other Rights may be granted
thereunder to any single employee from 250,000 to 350,000;

5. To ratify the selection by the Board of Directors of Arthur Andersen
LLP as the Company's independent public accountants for the year
ending December 31, 1998; and

6. To transact such other business as may properly come before the
meeting or any adjournment or postponement thereof.

Stockholders of record at the close of business on March 31, 1998 are
entitled to notice of, and to vote at, the meeting or any adjournment or
postponement thereof.

All stockholders are cordially invited to attend the meeting.

By order of the Board of Directors

JAS. MURRAY HOWE, Secretary

Boston, Massachusetts
April 23, 1998

WHETHER OR NOT YOU EXPECT TO ATTEND THE MEETING, PLEASE COMPLETE, DATE AND
SIGN THE ENCLOSED PROXY CARD AND PROMPTLY MAIL THE PROXY CARD IN THE ENCLOSED
ENVELOPE IN ORDER TO ASSURE REPRESENTATION OF YOUR SHARES AT THE MEETING. NO
POSTAGE NEED BE AFFIXED IF THE PROXY CARD IS MAILED WITHIN THE UNITED STATES.

<PAGE>

IRON MOUNTAIN INCORPORATED
745 Atlantic Avenue
Boston, Massachusetts 02111

PROXY STATEMENT
FOR THE ANNUAL MEETING OF STOCKHOLDERS

To be held on May 28, 1998

GENERAL INFORMATION

This Proxy Statement is furnished in connection with the solicitation of
proxies by the Board of Directors of Iron Mountain Incorporated (the "Board of
Directors"), a Delaware corporation ("Iron Mountain" or the "Company"), for use
at the Annual Meeting of Stockholders to be held on May 28, 1998 (the "Annual
Meeting") or at any adjournment or postponement thereof.

The Company's Annual Report to Stockholders for the year ended December
31, 1997 is being mailed to stockholders with the mailing of this Proxy
Statement on or about April 23, 1998.

All costs of solicitation of proxies will be borne by the Company. In
addition to solicitations by mail, the Company's Directors, officers and
regular employees, without additional remuneration, may solicit proxies by
telephone, telecopy and personal interviews. Brokers, banks, custodians and
other fiduciaries will be requested to forward proxy soliciting material to the
beneficial owners of stock held of record by such fiduciaries, and the Company
will reimburse them for their reasonable out-of-pocket expenses incurred in
connection with the distribution of such proxy materials.

Revocability of Proxies

Any stockholder giving a proxy in the enclosed form has the power to
revoke it at any time before it is exercised by delivering to the Secretary of
the Company at its principal executive office located at 745 Atlantic Avenue,
Boston, Massachusetts 02111, a written notice of revocation or another duly
executed proxy bearing a later date. A stockholder may also revoke his or her
proxy by attending the Annual Meeting and voting in person.

Record Date, Voting and Share Ownership

The Company's Common Stock, par value $.01 per share (the "Common Stock"),
is the only class of voting securities outstanding and entitled to vote at the
Annual Meeting. On March 31, 1998, the record date for the determination of
stockholders entitled to notice of and to vote at the Annual Meeting (the
"Record Date"), 14,975,477 shares of Common Stock were outstanding and entitled
to vote. Each share is entitled to one vote.

The presence at the Annual Meeting, in person or by proxy, of the holders
of a majority of the shares of Common Stock issued and outstanding on the
Record Date (7,487,739 shares) will constitute a quorum for the transaction of
business at the Annual Meeting. A proxy in the enclosed form, if received in
time for voting and not revoked, will be voted at the Annual Meeting in
accordance with the instructions contained therein. Where a choice is not so
specified, the shares represented by the proxy will be voted "for" the election
of the nominees for Director listed herein and in favor of the other matters
set forth in the Notice of Annual Meeting accompanying this Proxy Statement.

Shares represented by a properly signed and returned proxy will be treated
as present at the Annual Meeting for purposes of determining a quorum, without
regard to whether the proxy is marked as casting a vote or abstaining. Shares
represented by "broker non-votes" will also be treated as present for purposes
of determining a quorum, although such shares may not be voted on any matter
for which the record holder of such shares lacks authority

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<PAGE>

to act. Abstentions are also considered present for purposes of determining a
quorum. Abstentions and broker non-votes do not affect the election of the
Directors, the proposed adoption of the Iron Mountain Incorporated 1998
Employee Stock Purchase Plan (the "Employee Stock Purchase Plan"), the proposed
amendments to the Iron Mountain Incorporated 1995 Stock Incentive Plan (the
"Stock Incentive Plan") or the ratification of the accountants. Broker
non-votes are proxies with respect to shares held in record name by brokers or
nominees, as to which (i) instructions have not been received from the
beneficial owners or persons entitled to vote, (ii) the broker or nominee does
not have discretionary voting power under applicable national securities
exchange rules or the instrument under which it serves in such capacity and
(iii) the holder has indicated on the proxy card or otherwise notified the
Company that it does not have authority to vote such shares on that matter.

PRINCIPAL STOCKHOLDERS

The following table sets forth certain information known to the Company
with respect to beneficial ownership of Common Stock by (i) each stockholder
known by the Company to be the beneficial owner of more than five percent of
the Common Stock, (ii) each Director, (iii) the Chief Executive Officer and the
other executive officers identified in the Summary Compensation Table appearing
on page 10 and (iv) all executive officers and Directors of the Company as a
group. Such information is presented as of April 1, 1998. The following table
does not give effect to the Company's public offering of 4,025,000 shares of
Common Stock, which closed on April 3, 1998.

<TABLE>
<CAPTION>
Amount of Beneficial
Ownership(1)
Name Shares Percent Owned
- ----------------------------------------------------------------- ----------- --------------
<S> <C> <C>
Directors and Executive Officers
C. Richard Reese(2) ............................................... 1,127,503 7.5%
David S. Wendell(3) ............................................... 119,916 *
John F. Kenny, Jr.(4) ............................................. 54,539 *
Eugene B. Doggett(5) .............................................. 100,000 *
Robert G. Miller(6) ............................................... 14,974 *
Robert P. Swift(7) ................................................ 28,514 *
Constantin R. Boden(8) ............................................ 20,880 *
Arthur D. Little(9) ............................................... 26,265 *
Vincent J. Ryan(10) ............................................... 3,445,750 23.0%
B. Thomas Golisano(11) ............................................ 1,013,785 6.8%
Kent P. Dauten(12) ................................................ 964,449 6.4%
Clarke H. Bailey(13) .............................................. 503,939 3.3%
All Directors and executive officers as a group (17 persons)(14)... 6,799,888 44.4%

Five Percent Stockholders
Schooner Capital Corporation(15) .................................. 1,909,384 12.8%
William Blair & Company, L.L.C.(16) ............................... 894,399 6.0%
</TABLE>

- ------------
* Less than 1%

(1) Except as otherwise indicated, the persons named in the table above have
sole voting and investment power with respect to all shares of Common
Stock shown as beneficially owned by them.

(2) Mr. Reese is a Director and Chairman of the Board and Chief Executive
Officer of Iron Mountain. Includes 14,530 shares of Common Stock held by
trusts for the benefit of Mr. Reese's children, as to which Mr. Reese
disclaims beneficial ownership. Also includes 668,166 shares of Common
Stock as to which Mr. Reese shares

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<PAGE>

beneficial ownership with Schooner Capital Corporation ("Schooner") as a
result of a 1988 deferred compensation arrangement, as amended, between
Schooner and Mr. Reese relating to Mr. Reese's former services as President
of Schooner. Pursuant to such arrangement, upon the earlier to occur of (i)
Schooner's sale or exchange of substantially all of the shares of Common
Stock held by Schooner or (ii) the cessation of Mr. Reese's employment with
Iron Mountain, Schooner is required to transfer such shares of Common Stock
to Mr. Reese or remit to Mr. Reese cash in an amount equal to the then
current fair value of such shares of Common Stock. Schooner has agreed to
vote the shares of Common Stock subject to such arrangement at the
direction of Mr. Reese. Mr. Reese's address is c/o Iron Mountain
Incorporated, 745 Atlantic Avenue, Boston, Massachusetts 02111.

(3) Mr. Wendell is a Director and President and Chief Operating Officer of
Iron Mountain. Includes 116,061 shares that Mr. Wendell has the right to
acquire pursuant to currently exercisable options. Mr. Wendell's address
is c/o Iron Mountain Incorporated, 745 Atlantic Avenue, Boston,
Massachusetts 02111.

(4) Mr. Kenny is an Executive Vice President and Chief Financial Officer of
Iron Mountain. Includes 46,929 shares that Mr. Kenny has the right to
acquire pursuant to currently exercisable options. Mr. Kenny's address is
c/o Iron Mountain Incorporated, 745 Atlantic Avenue, Boston, Massachusetts
02111.

(5) Mr. Doggett is a Director and an Executive Vice President of Iron
Mountain. Mr. Doggett's address is c/o Iron Mountain Incorporated, 745
Atlantic Avenue, Boston, Massachusetts 02111.

(6) Mr. Miller is an Executive Vice President of Iron Mountain. Consists
solely of shares that Mr. Miller has the right to acquire pursuant to
currently exercisable options. Mr. Miller's address is c/o Iron Mountain
Incorporated, 745 Atlantic Avenue, Boston, Massachusetts 02111.

(7) Mr. Swift is an Executive Vice President of Iron Mountain. Consists solely
of shares that Mr. Swift has the right to acquire pursuant to currently
exercisable options. Mr. Swift's address is c/o Iron Mountain
Incorporated, 1340 East 6th Street, Los Angeles, California 90021.

(8) Mr. Boden is a Director of Iron Mountain. Mr. Boden's address is c/o Boden
Partners LLC, 450 Park Avenue, Suite 2302, New York, New York 10022.

(9) Mr. Little is a Director of Iron Mountain. Includes 25,000 shares held by
The Little Family Trust, as to which Mr. Little disclaims beneficial
ownership. Mr. Little's address is c/o The Little Investment Company, 33
Broad Street, Boston, Massachusetts 02109.

(10) Mr. Ryan is a Director of Iron Mountain. Mr. Ryan holds 1,536,366 shares
of Common Stock. The remaining shares of Common Stock listed as being
beneficially owned by Mr. Ryan are held by Schooner, as to which Mr. Ryan
has sole voting power and investment power as the Chairman of the Board
and principal stockholder of Schooner. Mr. Ryan's address is c/o Schooner
Capital Corporation, 745 Atlantic Avenue, Boston, Massachusetts 02111. See
footnote (15) regarding shares held by Schooner.

(11) Mr. Golisano is a Director of Iron Mountain. Includes 3,618 shares that
Mr. Golisano has the right to acquire pursuant to currently exercisable
options. Also includes 82,081 shares of Common Stock held in escrow
pursuant to the terms of the merger of Safesite Records Management
Corporation with and into a wholly-owned subsidiary of the Company. Mr.
Golisano's address is c/o Paychex Inc., 911 Panorama Trail South,
Rochester, New York 14625.

(12) Mr. Dauten is a Director of Iron Mountain. Includes 87,905 shares of
Common Stock held in escrow pursuant to the terms of the merger of
HIMSCORP, Inc. (doing business under the name Record Masters) ("Record
Masters") with and into a wholly-owned subsidiary of the Company. Also
includes 24,599 shares of Common Stock held in escrow by Mr. Dauten as
agent for the other former Record Masters stockholders. In addition,
includes approximately 365 shares of Common Stock, as to which Mr. Dauten
has shared voting power and

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<PAGE>

investment power as a partner of Madison Dearborn Partners IV, which has a
limited partnership interest in GKH Investments, L.P., a stockholder of the
Company. Mr. Dauten's address is c/o Keystone Capital, Inc., 520 Lake Cook
Road, Suite #450, Deerfield, Illinois 60015.

(13) Mr. Bailey is a Director of Iron Mountain. Includes 86,093 shares that Mr.
Bailey has the right to acquire pursuant to currently exercisable options.
Also includes 386,164 shares of Common Stock beneficially owned by Hudson
River Capital LLC ("Hudson"), of which Mr. Bailey is Co-Chairman of the
Board of Directors and a member. Hudson has sole voting and investment
power with respect to such shares. By virtue of Mr. Bailey's relationship
to Hudson, Mr. Bailey may be deemed to share voting and investment power
over such shares and to be the beneficial owner of such shares held by
Hudson. Mr. Bailey disclaims beneficial ownership of all such shares held
by Hudson. Mr. Bailey's address is 667 Madison Avenue, 25th Floor, New
York, New York 10021-8029.

(14) Includes 338,289 shares that directors and executive officers have the
right to acquire pursuant to currently exercisable options.

(15) Mr. Ryan is the Chairman of the Board and the principal stockholder of
Schooner and, accordingly, has sole voting and investment power with
respect to the shares of Common Stock held by Schooner. Includes 668,166
shares of Common Stock as to which Schooner shares beneficial ownership
with Mr. Reese as described in footnote (2). Schooner has agreed to vote
the shares of Common Stock subject to such arrangements at the direction
of Mr. Reese. The address of Schooner Capital Corporation is 745 Atlantic
Avenue, Boston, Massachusetts 02111.

(16) Includes 513,200 shares of Common Stock over which William Blair &
Company, L.L.C. has sole investment power, but over which customers of
William Blair & Company, L.L.C. have sole voting power. The address of
William Blair & Company, L.L.C. is 222 West Adams Street, Chicago,
Illinois 60606.

ITEM 1
ELECTION OF DIRECTORS

The Board of Directors currently consists of nine Directors. There are
three classes of Directors who serve for a three-year term and are elected on a
staggered basis, one class of three Directors standing for election each year.
The term of the Class C Directors, Eugene B. Doggett, Constantin R. Boden and
Clarke H. Bailey, will expire at the Annual Meeting; the term of the Class A
Directors, David S. Wendell, Vincent J. Ryan and B. Thomas Golisano, will
expire at the 1999 Annual Meeting of Stockholders; and the term of Class B
Directors, C. Richard Reese, Arthur D. Little and Kent P. Dauten, will expire
at the 2000 Annual Meeting of Stockholders. Directors of each class hold office
until the third annual meeting of the stockholders of the Company following
their election or until their successors are elected and qualified.

At the Annual Meeting, the three Class C Directors are to be elected to
serve until the Company's 2001 Annual Meeting of Stockholders, or until their
successors are elected and qualified. The Board of Directors has selected as
nominees the current Class C Directors of the Company, Eugene B. Doggett,
Constantin R. Boden and Clarke H. Bailey. Each has agreed to serve if elected,
and management has no reason to believe that any of the nominees will be
unavailable to serve. There are no arrangements or understandings between any
nominee and any other person pursuant to which such nominee was nominated.

The executive officers of the Company were last elected on May 29, 1997,
with the exceptions of Harold E. Ebbighausen and Christopher Neefus, who were
appointed in July 1997, and Richard A. Drutman and George P. Groff who were
elected in March 1998. At a meeting to be held immediately following the Annual
Meeting, the Board of Directors will reelect the current executive officers of
the Company. All executive officers hold office

4
<PAGE>

at the discretion of the Board of Directors until the first meeting of the
Board of Directors following the next annual meeting of stockholders and until
their successors are chosen and qualified. Except for T. Anthony Ryan, the
Company's Vice President, Real Estate, and Vincent J. Ryan, a Class A Director,
who are brothers, there are no family relationships between or among any
officers or Directors of the Company.

Required Vote

The affirmative vote of holders of a plurality of the shares cast at the
Annual Meeting is required to elect the Class C Directors.

The Board of Directors recommends that the stockholders vote FOR the
election of each of the nominees listed below to serve as Class C Directors of
the Company until the 2001 Annual Meeting of Stockholders, or until their
successors are elected and qualified.

Set forth below are the name and age of each Class C Director, his
principal occupation and business experience during the past five years and the
names of certain other companies of which he served as a Director as of April
1, 1998.

<TABLE>
<CAPTION>
Principal Occupations and Business Experience
Nominee During the Past 5 Years
- --------------------- -------------------------------------------------------------------------------------------
<S> <C>
Eugene B. Doggett Mr. Doggett is a Class C Director and an Executive Vice President of the Company,
Age 61 positions that he has held since 1990. From 1987 until May 1997, Mr. Doggett was the
Chief Financial Officer of Iron Mountain. Mr. Doggett is also a Director of Schooner
Capital Corporation ("Schooner") and of Mac-Gray Corporation, a publicly held
supplier of card and coin-operated laundry services in multiple housing facilities. Prior
to joining the Company, he had extensive experience in commercial and investment
banking, as well as financial and general management experience at senior levels. He
holds a Master of Business Administration degree from Harvard Business School.

Constantin R. Boden Mr. Boden is a Class C Director of the Company, a position that he has held since
Age 61 December 1990. Mr. Boden is the principal of Boden Partners LLC and chairman of the
advisory board of Boston Capital Ventures, a risk capital concern. For 34 years, until
January 1995, Mr. Boden was employed by The First National Bank of Boston, most
recently as Executive Vice President, International Banking. He holds a Master of
Business Administration degree from Harvard Business School.

Clarke H. Bailey Mr. Bailey is a Class C Director of the Company, a position that he has held since January
Age 43 1998, when he was appointed to the Board of Directors in accordance with the terms
of the merger of Arcus Group, Inc. ("Arcus Group") with and into the Company (the
"Arcus Group Merger"). He is Co-Chairman and Director of Hudson River Capital LLC,
a private investment company. Mr. Bailey was the Chairman and Chief Executive Officer
of each of Arcus Group, United Acquisition Company and Arcus Technology Services,
Inc. ("Arcus"), positions which he had held since 1995, until the Arcus Group Merger,
and is a Director of Connectivity Technologies Inc., Swiss Army Brands, Inc. and
SWWT, Inc. (formerly known as Sweetwater, Inc.). Mr. Bailey also serves as Director
and Chairman of the Executive Committee of Glenayre Technologies, Inc., a
manufacturing company in the telecommunications industry. Prior to joining Glenayre
in 1990, Mr. Bailey was a Managing Director at Oppenheimer & Co., Inc. He holds a
Master of Business Administration degree from The Wharton School, University of
Pennsylvania.
</TABLE>

5
<PAGE>

Set forth below are the name and age of each other Director and executive
officer, his principal occupation and business experience during the past five
years and the names of certain other companies of which he served as a Director
as of April 1, 1998.

<TABLE>
<CAPTION>
Principal Occupations and Business Experience
Nominee During the Past 5 Years
- -------------------- ------------------------------------------------------------------------------------------
<S> <C>
C. Richard Reese Mr. Reese is a Class B Director of the Company, a position that he has held since 1990,
Age 52 the Chairman of the Board of Directors of the Company, a position that he has held since
November 1995, and the Chief Executive Officer of the Company, a position that he has
held since 1981. Prior to November 1995, Mr. Reese was the President of Iron Mountain,
a position that he had held since 1981. Mr. Reese is also a Director of Schooner, which
owns approximately 12.8% of the outstanding stock of the Company. Prior to joining
Iron Mountain, he lectured at Harvard Business School in "Entrepreneurship" and
provided consulting services to small and medium-sized emerging enterprises. Mr.
Reese has also served as president and a Director of Professional Records and
Information Services Management ("PRISM"), a trade group of approximately 450
members. He holds a Master of Business Administration degree from Harvard Business
School.

David S. Wendell Mr. Wendell is a Class A Director and the President and Chief Operating Officer of the
Age 44 Company, positions that he has held since November 1995. After practicing law with
Brown & Wood, Mr. Wendell joined Iron Mountain in 1984, where he has served in a
variety of positions. Prior to November 1995, he was Executive Vice President, Atlantic
Area and prior to 1991, he was Vice President, New England Region. He holds a Master
of Business Administration degree from Harvard Business School and a Juris Doctor
degree from the University of Virginia.

John F. Kenny, Jr. Mr. Kenny is an Executive Vice President and the Chief Financial Officer of the
Age 40 Company, positions that he has held since May 1997. Mr. Kenny joined Iron Mountain
in 1991, and held operating responsibilities as regional Vice President of New England
and later Northeast operations before assuming the position of Vice President of
Corporate Development in 1995. Prior to 1991, he was Vice President of CS First Boston
Merchant Bank, New York, with responsibility for risk capital investments. Mr. Kenny
has also served as a director and the Treasurer of PRISM. He holds a Master of Business
Administration degree from Harvard Business School.

Richard S. Drutman Mr. Drutman is an Executive Vice President of the Company, a position that he has held
Age 55 since March 1998. Mr. Drutman joined the Company in January 1998. Mr. Drutman
joined Arcus Data Security, Inc. in 1976 and held various positions, including Senior
Vice President and Chief Operating Officer from 1991 to 1996 and President and Chief
Executive Officer from 1996 to January 1998. He holds a Bachelor of Arts degree from
California State University at Los Angeles.

Arthur D. Little Mr. Little is a Class B Director of the Company, a position that he has held since
Age 54 November 1995. Mr. Little is a principal of The Little Investment Company, which he
founded in 1992. Prior to that, he was Managing Director of and also a partner in
Narragansett Capital, Inc., a private investment firm. He holds a Bachelor of Arts degree
in history from Stanford University.
</TABLE>

6
<PAGE>

Robert G. Miller Mr. Miller is an Executive Vice President of the Company, a position that he has held
Age 41 since December 1996. Mr. Miller joined Iron Mountain in 1988 and held various
positions including District Manager from 1988 through 1991 and regional Vice
President from 1991 through 1996. Prior to 1988, Mr. Miller was employed as a District
Manager at Bell & Howell Records Management Company.

Kenneth F. Radtke, Jr. Mr. Radtke is an Executive Vice President of Iron Mountain, a position that he has held
Age 52 since June 1996. Prior to June 1996, Mr. Radtke was Northeast Regional Vice President
and prior to 1995 was Sales Manager, New York Region. Mr. Radtke has worked in the
records and information industry since 1988 as President and Chief Executive Officer,
Dataport Company, Inc. and Senior Vice President of a subsidiary of Arcus. He holds
a graduate degree from the University of Wisconsin, Graduate School of Banking.

Harold E. Ebbighausen Mr. Ebbighausen is an Executive Vice President of the Company, a position that he has
Age 43 held since July 1997. Prior to 1997, he had been serving as Vice President of Data
Security Services since joining the Company in September 1996. Prior to joining Iron
Mountain, Mr. Ebbighausen was Vice President of Document Management Services
with INSCI Corporation, a software provider for computer output and data storage
solutions to optical and CD technology. Previously, he held a number of field
management positions with Anacomp, Inc., a service bureau provider in the
micrographics industry.

George P. Groff Mr. Groff is the President of Arcus Staffing Resources, Inc., a subsidiary of the Company,
Age 48 a position that he has held since March 1998. From 1993 to March 1998, Mr. Groff served
as a Vice President of Arcus Staffing Resources, Inc. and of Wolf Advisory International,
Inc., a company which he joined in 1989 that was acquired by Arcus in 1996. He holds
a Master of Business Administration degree from Golden Gate University.

Christopher Neefus Mr. Neefus is an Executive Vice President of the Company, a position that he has held
Age 42 since July 1997. Mr. Neefus was a Vice President of Sales and Customer Service for
ASI, Inc., a software provider for the storage of computer generated information, from
1995 until joining the Company. From 1990 to 1995, Mr. Neefus was the Region Vice
President of Anacomp, Inc., a service bureau provider in the micrographics industry. Mr.
Neefus holds a Bachelor of Arts degree in Communications Arts from Hofstra
University.

Robert P. Swift Mr. Swift is an Executive Vice President of the Company, a position that he has held
Age 56 since November 1995. Prior to November 1995, Mr. Swift was the Executive Vice
President, Western Area of Iron Mountain and prior to 1988, Mr. Swift was employed
in various positions at Bell & Howell Records Management Company.
</TABLE>

7
<PAGE>

<TABLE>
<CAPTION>
Principal Occupations and Business Experience
Nominee During the Past 5 Years
- -------------------- ----------------------------------------------------------------------------------------
<S> <C>
B. Thomas Golisano Mr. Golisano is a Class A Director of the Company, a position that he has held since
Age 56 June 1997, when he was appointed to the Board of Directors in accordance with the terms
of the Safesite Records Management Corporation ("Safesite") merger. He founded
Paychex Inc., a publicly held, national payroll service company, in 1971 and serves as
its Chairman, President and Chief Executive Officer. Mr. Golisano serves on the Board
of Trustees of Rochester Institute of Technology and on the boards of several privately
held companies. He has also served on the boards of numerous non-profit organizations
and is the founder of the B. Thomas Golisano Foundation.

Kent P. Dauten Mr. Dauten is a Class B Director of the Company, a position that he has held since
Age 42 November 1997, when he was appointed to the Board of Directors in accordance with
the terms of the merger of HIMSCORP, Inc. (doing business under the name Record
Masters ("Record Masters") with and into a wholly-owned subsidiary of the Company
("Record Masters Merger"). He has served as President of Keystone Capital, Inc., a
management and consulting advisory service firm, since March 1994. In February 1995,
Mr. Dauten founded and served as President of Record Masters, until the consummation
of the Record Masters Merger. From 1993 to 1994, he was Senior Vice President of
Madison Dearborn Partners, Inc. and from 1979 to 1992, he was employed in various
investment management positions, most recently as Senior Vice President of First
Chicago Venture Capital. Mr. Dauten currently serves as a director of Health
Management Associates, Inc., a hospital management firm and is a Trustee of ElderTrust,
a health care real estate investment trust. Mr. Dauten holds a Master of Business
Administration from Harvard Business School.
</TABLE>

Board and Committee Meetings

During the fiscal year ended December 31, 1997, the Board of Directors
held five regular meetings and three special meetings held by telephone and
took actions by written consent. Each incumbent Director who was then in office
(other than Mr. Little, who was unavailable for the telephone meetings)
attended at least 75% of the aggregate number of meetings of the Board of
Directors and all committees thereof on which such Director served. The Board
of Directors has a standing Audit Committee, Compensation Committee and
Executive Committee, and a Stock Incentive Plan Subcommittee of the
Compensation Committee (the "Option Plan Subcommittee"). The Company does not
have a nominating committee. During the fiscal year ended December 31, 1997,
the Audit Committee held one meeting, the Option Plan Subcommittee held three
meetings and took actions by written consent, the Compensation Committee held
two meetings and the Executive Committee held no formal meetings.

The Audit Committee consists of Messrs. Boden (Chairman) and Little. The
Audit Committee consults with the Company's independent public accountants
regarding the plan for the Company's annual audit, reviews with the public
accountants their audit report and related management letter, reviews the
performance of the independent public accountants and their fees, reviews the
Company's internal accounting control policies and procedures and considers and
recommends the selection of the Company's independent public accountants.

The Compensation Committee consists of Messrs. Little (Chairman), Boden
and Ryan. The Compensation Committee provides recommendations to the Board
regarding compensation policies and programs of the Company and is also
responsible for establishing and modifying the compensation for all executive
officers of the Company.

The Option Plan Subcommittee consists of Messrs. Little (Chairman) and
Boden, both of whom are "outside" and "non-employee" directors within the
meaning of Section 162(m) of the Internal Revenue Code of 1986, as

8
<PAGE>

amended (the "Code"), and Rule 16b-3 under Section 16 of the Securities and
Exchange Act of 1934, as amended (the "Exchange Act"), respectively. The Option
Plan Subcommittee administers the Stock Incentive Plan, including the grant of
stock options thereunder to all employees, including executive officers, the
Iron Mountain/UAC 1995 Stock Option Plan and the Iron Mountain/ATSI 1995 Stock
Option Plan and recommends the adoption of, and any amendments to, all stock
incentive plans. If approved by the stockholders, the Option Plan Subcommittee
will administer the Employee Stock Purchase Plan.

The Executive Committee consists of Messrs. Ryan (Chairman), Reese and
Doggett. Between meetings of the Board of Directors, the Executive Committee
exercises all the powers of the Board of Directors in the management and
direction of the business and affairs of the Company to the extent not
otherwise prohibited by law, the Board of Directors or the Company's Bylaws or
Amended and Restated Certificate of Incorporation.

Director Compensation

Directors who are employees of Iron Mountain do not receive additional
compensation for serving as Directors. Each Director who is not an employee of
Iron Mountain receives an annual retainer fee of $10,000 as compensation for
his or her services as a member of the Board of Directors and is also paid
$2,500 per quarter (to a maximum of $10,000 per year) for attendance at
meetings (the "Director's Compensation"). Director's Compensation is prorated
for Directors who join the Company during the year. All Directors are
reimbursed for out-of-pocket expenses incurred in attending meetings of the
Board of Directors or committees thereof, and for other expenses incurred in
their capacities as Directors. Directors may be granted options, either in lieu
of or in addition to the Director's Compensation, under the Stock Incentive
Plan.

The Company paid a total of $54,298 in cash for Directors fees in respect
of services for 1997. In addition, in lieu of cash, Messrs. Boden and Little
each received 370 shares of Common Stock in payment of fees for the period
January 1, 1997 through June 30, 1997 pursuant to the Iron Mountain
Incorporated 1995 Stock Plan for Non-Employee Directors, which was terminated
effective June 30, 1997. Pursuant to that plan, Messrs. Boden and Little had
made irrevocable elections to receive their Director's Compensation in the form
of Common Stock equivalent to 110% of the Director's Compensation otherwise due
to be paid in cash. Messrs. Boden and Little received their Director's
Compensation for the period July 1, 1997 through December 31, 1997 in cash. The
other non-employee Directors received all of their Director's Compensation in
cash.

9
<PAGE>

EXECUTIVE COMPENSATION

The following table provides certain information concerning compensation
earned by the Chief Executive Officer and the other four most highly
compensated executive officers who received compensation in excess of $100,000
in 1997 (the "Named Executive Officers") for the years ended December 31, 1995,
1996 and 1997.

Summary Compensation Table

<TABLE>
<CAPTION>
Annual Compensation Long-Term Compensation
------------------------- --------------------------------
Number of
Shares
Name and Underlying All Other
Principal Position Year Salary Bonus Options Compensation (1)
- -------------------------------------- ------ ----------- ----------- ------------ -----------------
<S> <C> <C> <C> <C> <C>
C. Richard Reese ..................... 1997 $298,381 $200,000 0 $4,000
Chairman of the Board and Chief 1996 $268,958 $165,000 0 $1,941
Executive Officer 1995 $261,765 $200,000 0 $1,790

David S. Wendell ..................... 1997 $221,723 $150,000 31,496 $4,000
President and Chief Operating Officer 1996 $203,550 $125,000 40,000 $1,941
1995 $136,627 $ 62,731 35,469 $1,573

John F. Kenny, Jr. ................... 1997 $166,723 $150,000 105,512 $2,400
Executive Vice President and Chief 1996 $129,723 $ 49,999 33,000 $1,618
Financial Officer 1995 $114,377 $ 36,715 39,509 $1,307

Robert P. Swift ...................... 1997 $145,542 $ 54,991 0 $4,000
Executive Vice President 1996 $133,600 $ 50,800 15,000 $1,643
1995 $131,119 $ 24,397 8,096 $1,243

Robert G. Miller ..................... 1997 $133,646 $ 41,875 0 $4,000
Executive Vice President 1996 $105,473 $ 35,034 20,000 $2,173
1995 $ 86,696 $ 24,569 5,072 $ 977
</TABLE>

- ------------
(1) Reflects the Company's matching contribution to the Iron Mountain Profit
Sharing Retirement Plan for each individual. Amounts shown for 1997 are
estimated maximum contributions; the actual contributions have not yet
been calculated.

10
<PAGE>

The following table sets forth certain information concerning the grant of
options to purchase Common Stock to the Named Executive Officers. None of the
other Named Executive Officers were granted stock options in the year ended
December 31, 1997.

Option Grants in 1996

<TABLE>
<CAPTION>
Potential Realizable
Percent Value at Assumed
of Total Annual Rates of Stock
Number of Options Appreciation for
Securities Granted to Exercise Option Term(1)
Name and Underlying Employees in Price Expiration ----------------------------
Principal Position Options Granted Fiscal Year 1996 ($/Sh) Date 5% 10%
- ----------------------------- ----------------- ------------------ ----------- ----------- ------------- -------------
<S> <C> <C> <C> <C> <C> <C>
David S. Wendell ............ 31,496 6.71% $ 31.75 7/30/07 $ 629,000 $1,594,000
President and Chief
Operating Officer

John F. Kenny, Jr. .......... 105,512 22.49% $ 31.75 7/30/07 $2,107,000 $5,339,000
Executive Vice President
and Chief Financial
Officer
</TABLE>

- ------------
(1) Potential Realizable Value is based on the assumed growth rates for an
assumed ten-year option term. Five percent annual growth results in a
Common Stock price per share of $51.72, and ten percent annual growth
results in a Common Stock price per share of $82.35, respectively, for
such term. The actual value, if any, an executive may realize will depend
on the excess of the market price of the Common Stock over the exercise
price on the date the option is exercised. There is no assurance that the
value realized by an executive will be at or near the amounts reflected in
this table.

The following table sets forth certain information with respect to the
exercise of stock options during the year ended December 31, 1997 by, and the
unexercised options to purchase Common Stock of, the Named Executive Officers.
Mr. Reese does not have any unexercised options.

Aggregate Option Exercises in Last Fiscal Year and Fiscal Year End Option
Values

Number of Unexercised Value of Unexercised
Options at In-the-Money-Options at
Shares December 31, 1997 December 31, 1997(1)
Name and Acquired on Value ----------------------------- -----------------------------
Principal Position Exercise Realized Exercisable Unexercisable Exercisable Unexercisable
- -------------------------------------- ------------- ---------- ------------- --------------- ------------- --------------
<S> <C> <C> <C> <C> <C> <C>
David S. Wendell ..................... 3,000 $80,634 100,967 91,872 $2,840,630 $1,357,831
President and Chief Operating Officer
John F. Kenny, Jr. ................... 0 0 32,427 157,160 $ 806,046 $1,562,388
Executive Vice President and Chief
Financial Officer
Robert P. Swift ...................... 0 0 23,895 18,477 $ 663,003 $ 376,230
Executive Vice President
Robert G. Miller ..................... 0 0 9,960 19,738 $ 247,827 $ 407,703
Executive Vice President
</TABLE>

- ------------
(1) Based on a year-end value of $36.00 per share, less the exercise price.

11
<PAGE>

Compensation Committee Report on Executive Compensation

The Compensation Committee consists entirely of Directors who are not
employees of the Company. It is the Compensation Committee's responsibility to
review, recommend and approve the Company's compensation policies and programs,
including all compensation for the Chief Executive Officer and the other
executive officers of the Company.

The Option Plan Subcommittee consists entirely of directors who are both
"non-employee" directors within the meaning of Rule 16b-3 under Section 16 of
the Exchange Act and "outside" directors within the meaning of Section 162(m)
of the Code and the regulations thereunder, so that grants of options under the
Stock Incentive Plan to executive officers are exempt under Rule 16b-3 and
eligible for the "performance-based" exception of Section 162(m) of the Code.
The Option Plan Subcommittee administers the Stock Incentive Plan and in
exercise of that function determines what grants of stock options, restricted
stock and stock appreciation rights ("SARs") thereunder are to be made to the
Chief Executive Officer and the other executive officers. The Option Plan
Subcommittee also administers the Iron Mountain/UAC 1995 Stock Option Plan and
the Iron Mountain/ATSI 1995 Stock Option Plan, although no additional grants
are to be made under those plans.

The purpose of the Stock Incentive Plan is to encourage key employees,
Directors and consultants of the Company who render services of special
importance to, and who have contributed or are expected to contribute
materially to the success of, the Company to continue their association with
the Company by providing favorable opportunities for them to participate in the
ownership of the Company and in its future growth. The Option Plan Subcommittee
made stock option grants to Messrs. Wendell, Kenny, Ebbighausen and Neefus in
July 1997. In addition, the Option Plan Subcommittee made a stock option grant
to B. Thomas Golisano in June 1997 in connection with the acquisition by the
Company of Safesite.

The Compensation Committee determined the salary levels of the Company's
executive officers, including the Chief Executive Officer, for fiscal year
1997, as well as the amounts of bonuses paid in 1998 for performance in fiscal
year 1997. The compensation policies implemented by the Compensation Committee,
which combine base salary and incentive compensation in the form of cash
bonuses and long-term stock options, are designed to achieve the operating and
acquisition strategies and goals of the Company. In particular, in determining
bonuses paid in 1998 in respect of 1997 and salary levels for fiscal year 1997,
the Compensation Committee took into account the past or expected future
contributions of each executive officer to the Company's strategic goals,
especially the efforts of each such officer in connection with (1) pursuing and
effecting the offering and sale of the Company's 8-3/4% Senior Subordinated
Notes due 2009 to augment available funding for the Company's growth strategy
and (2) increasing the Company's growth rate by successfully identifying,
acquiring and integrating other records management businesses, while at the
same time maintaining the Company's internal growth.

Section 162(m) of the Code generally disallows an income tax deduction to
public companies for compensation in excess of $1,000,000 paid in any year to
the chief executive officer or any of the four most highly compensated other
executive officers, to the extent that this compensation is not
"performance-based" within the meaning of Section 162(m). Although the
Compensation Committee has not adopted any specific rules with respect to this
issue, its general policy, subject to all then prevailing relevant
circumstances, is to attempt to structure the compensation arrangements of the
Company to maximize deductions for federal income tax purposes.

COMPENSATION COMMITTEE

ARTHUR D. LITTLE, Chairman
CONSTANTIN R. BODEN
VINCENT J. RYAN

12
<PAGE>

Change of Control Arrangement

The Stock Incentive Plan provides for acceleration of the vesting of
options and SARs if the Company or any wholly owned subsidiary of the Company
is a party to a merger or consolidation (whether or not the Company is the
surviving corporation) in any transaction or series of related transactions and
there is a "Limited Change of Control" of the Company. A Limited Change of
Control occurs if after the merger or consolidation (a) individuals who
immediately prior to the merger or consolidation served as members of the Board
of Directors no longer constitute a majority of the Board of Directors or the
board of directors of the surviving corporation and (b) the voting securities
of the Company outstanding immediately prior to the merger or consolidation do
not represent (either by remaining outstanding or upon conversion into
securities of the surviving corporation) more than 50% of the voting power of
the securities of the Company or the surviving corporation immediately after
the merger or consolidation. In addition, if the Company is not the surviving
corporation, a holder of options or SARs is entitled to receive upon exercise
of his or her options or SARs the number and class of shares of stock or other
securities and any other consideration of the surviving or resulting
corporation that the optionee or holder of SARs would have been entitled to
receive pursuant to the merger or consolidation had the optionee or holder of
SARs held the shares of Common Stock subject to the option or SAR.

Compensation Committee Interlocks and Insider Participation

The present Compensation Committee consists of Mr. Little, who is the
Chairman, and Messrs. Boden and Ryan. Messrs. Reese and Doggett are executive
officers of Iron Mountain and Directors of Schooner. Mr. Ryan is Chairman of
the Board and principal stockholder of Schooner.

Certain Transactions

Real Estate Transactions

Iron Mountain Records Management, Inc. ("IMRM"), a subsidiary of the
Company, is the tenant under a lease dated January 1, 1991 for a 31,500
square-foot building in Houston, Texas. The owner of the building is IM Houston
(CR) Limited Partnership, a Texas limited partnership, of which Mountain
Realty, Inc., a Massachusetts corporation whose sole stockholder is Mr. Ryan,
is the sole general partner, and the limited partners of which are Messrs.
Ryan, Reese and Doggett. The term of the lease expires December 31, 2000, with
two five-year extension options exercisable by IMRM. IMRM paid annual rent of
approximately $99,326 for the year ended December 31, 1997, and currently pays
annual rent of approximately $99,326, subject to adjustment in 1999 (and in the
option periods if the term is extended) based upon percentage changes in the
consumer price index, with a floor of 3% and a ceiling of 5%, compounded
annually. As tenant, IMRM is responsible for taxes, insurance and maintenance.
The space is used by IMRM as a records management facility. The lease is, in
the opinion of management, on commercially reasonable terms and is no less
favorable to IMRM than could have been obtained from an unaffiliated party at
the time of the transaction.

Schooner leases space from the Company at the Company's corporate
headquarters. Such lease is a tenancy-at-will and may be terminated by either
the Company or Schooner at any time. As consideration for such lease, Schooner
pays rent to the Company based on its pro rata share of all expenses related to
the use and occupancy of the premises. The rent paid by Schooner to Iron
Mountain under such lease was approximately $85,428 in the year ended December
31, 1997, and Schooner currently pays annual rent of approximately $85,428.

Other Transactions

The Company paid compensation of $165,695 for the year ended December 31,
1997 to Mr. T. Anthony Ryan. Mr. Ryan is Vice President, Real Estate, of the
Company and is the brother of Mr. Vincent J. Ryan, a Director of the Company.
The Company believes that the terms of Mr. Ryan's employment are no less
favorable to it than would be negotiable with an unrelated third party.

13
<PAGE>

In November 1997, the Company entered into a management advisory agreement
with Keystone Capital, Inc., of which Kent P. Dauten, a Class B Director of the
Company, is president. Keystone Capital, Inc. receives fees of approximately
$20,000 per month under such agreement relating to consulting with respect to
medical records management services. The Company believes that the terms of the
management advisory agreement are no less favorable to it than would be
negotiable with an unrelated third party.

Performance Graph

The following graph compares the percentage change in the Company's Common
Stock to the cumulative total returns of the Nasdaq Market Index and the
Standard & Poor's Small Cap 600 Index (the "Small Cap Index") for fiscal year
1997 and for the portion of 1996 that the Common Stock was traded on The Nasdaq
Stock Market's National Market (the "Nasdaq National Market"), assuming an
investment of $100 on February 1, 1996. The company most comparable in size and
operations to the Company was not publicly traded for the full year 1997 and,
accordingly, could not be included in a peer group comparison. The Company
believes that a peer group index excluding such competitor would be misleading,
as other publicly traded companies that might be part of a peer group differ
significantly in scale and type of operations from the Company. The Company has
therefore elected to use the Small Cap Index for comparison purposes. The
cumulative return assumes reinvestment of all dividends during each month. The
performance of the Company's Common Stock reflected below is not necessarily
indicative of future performance.

Comparison of Cumulative Total Return of Iron Mountain Incorporated,
Nasdaq Market Index and Standard & Poor's Small Cap 600 Index

[TABULAR REPRESENTATION OF LINE CHART]

Feb 96 Dec 96 Dec 97
------ ------ ------
IRON MOUNTAIN INC. 100 189 225
NASDAQ COMPOSITE INDEX 100 122 150
S&P SMALLCAP 600 INDEX 100 121 152

Assumes $100 invested on February 1, 1996
Assumes dividends reinvested
Fiscal year ended December 31, 1997

14
<PAGE>

ITEM 2
ADOPTION OF THE EMPLOYEE STOCK PURCHASE PLAN

On March 23, 1998 the Board of Directors approved, and is proposing for
stockholder approval, the adoption of the Employee Stock Purchase Plan. The
purpose of the Employee Stock Purchase Plan is to provide employees of the
Company and its "Subsidiaries" (a corporation the voting power of which is at
least 50% owned by the Company, directly or indirectly, whether or not such
corporation now exists or is hereafter organized or acquired by the Company or
a Subsidiary) the opportunity to acquire a proprietary interest in the Company
by providing favorable terms for them to purchase its stock.

The Board of Directors believes that equity interests are a significant
factor in the Company's ability to attract, retain and motivate employees that
are critical to the Company's long-term success and that the adoption of the
Employee Stock Purchase Plan will further the goal of providing employees with
incentives to serve the Company.

On April 1, 1998, the closing price per share of the Company's Common
Stock, as reported in a summary of composite transactions in The Wall Street
Journal for stocks listed on Nasdaq National Market, was $37.625.

Employee Stock Purchase Plan

The following is a summary of the Employee Stock Purchase Plan and is
subject to and qualified in its entirety by reference to the complete text of
the Employee Stock Purchase Plan, a copy of which is set forth in Exhibit A to
this Proxy Statement.

Overview. The total amount of Common Stock with respect to which the right
to purchase Common Stock may be granted under the Employee Stock Purchase Plan
will not exceed in the aggregate 250,000 shares. If an option granted under the
Employee Stock Purchase Plan expires or is surrendered or cancelled, the shares
allocable to the option will again be available under the plan. Options under
the Employee Stock Purchase Plan will be granted in a series of offerings of
Common Stock (each an "Offering"), the first of which will be on September 1,
1998 (such date and each September 1 thereafter is referred to as an "Offering
Date") until all of the shares of Common Stock available under the Employee
Stock Purchase Plan have been exhausted, or until the Employee Stock Purchase
Plan has been terminated by the Board of Directors or has terminated by its
terms. On August 31, 1999 (such date and each August 31 thereafter is referred
to as an "Exercise Date") the option will be exercised and payroll deductions
accumulated during the Offering will be used to pay the "Option Price." Each
participant will purchase the number of whole shares of Common Stock equal to
the accumulated payroll deductions credited to his or her account during the
Offering divided by the Option Price. (If insufficient shares are available, a
pro rata allocation of remaining shares will be made.) The "Option Price" of
shares of Common Stock will be the lesser of: (i) 85% of the fair market value
of the shares on the Offering Date or (ii) 85% of the fair market value of the
shares on the Exercise Date. Fair market value will generally be the mean
between the highest and lowest sale price of the stock on the date in question.
In no event will a participant be granted an option to acquire more than the
number of whole shares of Common Stock equal to $25,000 divided by the fair
market value of the shares as of the Offering Date.

Eligibility and Participation. Any employee of the Company or any
Subsidiary who is customarily employed for more than twenty hours per week and
more than five months in a calendar year by the Company or any Subsidiary may
become a participant in any future Offering under the Employee Stock Purchase
Plan by completing an authorization for after-tax payroll deductions in
connection with the Offering prior to the Offering Date. A participant may
authorize payroll deductions of from one to fifteen percent of his or her
compensation on each pay day. A participant can decrease his or her rate of
deductions and can withdraw entirely from an Offering, but he or she can never
increase the rate of payroll deductions once an Offering begins.

The following employees are ineligible to participate: (i) any employee
who is a member of a collective bargaining unit that has elected not to
participate in the Employee Stock Purchase Plan and (ii) any employee who

15
<PAGE>

owns, directly or indirectly, as of an Offering Date five percent or more of
the Company or of any Subsidiary. In addition, no employee will be granted an
option that would cause him or her to own (or be considered to own) or hold
outstanding options to purchase five percent or more of the total combined
voting power or value of all classes of capital stock of the Company or any
Subsidiary or that permits his or her right to purchase shares under all
employee stock purchase plans of the Company and its Subsidiaries to accrue at
a rate that exceeds $25,000 for any calendar year.

Administration. The Employee Stock Purchase Plan, which is effective April
1, 1998, may be administered by the Board of Directors or, in its discretion,
by a committee composed of at least two individuals who may be members of the
Board of Directors or employees of the Company. The Board of Directors has
determined that if the Employee Stock Purchase Plan is approved by the
stockholders, it will initially be administered by the Option Plan
Subcommittee. The Option Plan Subcommittee shall have the authority to adopt,
amend and rescind such rules and regulations as, in its opinion, may be
advisable in the administration of the Employee Stock Purchase Plan and to
decide all questions of interpretation and application of such rules and
regulations, which decision is final and binding. The Option Plan Subcommittee
has the authority to change the Offering Date and the Exercise Date, as well as
the authority to increase the number of Offerings each year.

Withdrawal. A participant may, at such time prior to the Exercise Date and
in such manner as the Option Plan Subcommittee may prescribe, withdraw from an
Offering and receive payment of an amount in cash equal to the accumulated
payroll deductions credited to the participant's account under the Employee
Stock Purchase Plan. In no event will a participant receive interest with
respect to his or her payroll deductions, whether used to purchase Common Stock
or returned in cash.

Termination of Employment. Options shall not be transferable by a
participant and no amount credited to a participant's account may be assigned,
transferred, pledged or otherwise disposed of in any way by a participant. Upon
termination of a participant's employment with the Company or a Subsidiary for
any reason other than death, an amount in cash equal to the accumulated payroll
deductions then credited to the participant's account under the Employee Stock
Purchase Plan will be paid to the participant. In the event that a participant
dies prior to the Exercise Date, the executor, the administrator or a personal
representative of the estate may request that the balance of the participant's
account be used to exercise the option granted prior to the participant's
death. Any such election shall be made not later than the Exercise Date.

Restrictions on Transfer. A participant may not sell, assign, pledge,
encumber or otherwise transfer Common Stock acquired pursuant to the exercise
of an option until after the first anniversary of the Exercise Date on which
the shares were purchased. The Option Plan Subcommittee, however, may in its
discretion extend, shorten or eliminate entirely this restriction. The stock
certificate or certificates evidencing shares of Common Stock issued pursuant
to the exercise of an option will bear a legend setting forth any restriction.

Forfeiture for Dishonesty. If the Board of Directors determines that a
participant has engaged in fraud, embezzlement, theft, commission of a felony
or proven dishonesty in the course of his or her employment that has damaged
the Company or a Subsidiary or has disclosed trade secrets or other proprietary
information of the Company or a Subsidiary, (a) the individual's participation
in an Offering will terminate and he or she will forfeit his or her right to
receive any Common Stock pursuant to an Offering that has not yet been
delivered and (b) the Company will have the right to repurchase all or any part
of the shares of Common Stock acquired by the participant upon the earlier
exercise of any option, at a price equal to the amount paid to the Company upon
exercise, together with interest.

Change in Capital Structure. In the event that there is a change in the
capital structure of the Company, by reason of a reorganization,
recapitalization, exchange of shares, stock split, combination of shares or
dividend payable in shares or other securities, a corresponding adjustment will
be made by the Option Plan Subcommittee in

16
<PAGE>

the number and kind of shares or other securities covered by outstanding
options and for which options may be granted under the Employee Stock Purchase
Plan, and in the Option Price. If while unexercised options remain outstanding
under the Employee Stock Purchase Plan the Company merges or consolidates with
one or more corporations (whether or not the Company is the surviving
corporation), or is liquidated or sells or otherwise disposes of substantially
all of its assets to another entity, or upon a Change of Control (as defined
below), then the Option Plan Subcommittee, in its discretion, shall provide
that either: (i) after the effective date of the merger, consolidation,
liquidation, sale or Change of Control, each participant is entitled, upon
exercise of an option, to receive in lieu of shares of Common Stock the number
and class of shares of such stock or other securities to which he or she would
have been entitled pursuant to the terms of the merger, consolidation,
liquidation, sale or Change of Control if he or she had been the holder of
record of the number of shares of Common Stock as to which the option is being
exercised; or (ii) all outstanding options shall be exercised as of the day
preceding the merger, consolidation, liquidation, sale or Change of Control,
which day shall be the Exercise Date for the Offering, except that each
participant shall be notified of his or her right to withdraw from the Offering
and receive a refund of payroll deductions then credited to his or her account.

A "Change of Control" shall be deemed to have occurred if any person (as
such term is used in Section 13(d) and 14(d)(2) of the Exchange Act) other than
a trust related to an employee benefit plan maintained by the Company becomes
the beneficial owner (within the meaning of Rule 13d-3 under the Exchange Act)
of 50% or more of the Company's outstanding Common Stock, and within the period
of 24 consecutive months immediately thereafter, individuals other than (i)
individuals who at the beginning of such period constitute the entire Board of
Directors, or (ii) individuals whose election, or nomination for election by
the Company's stockholders, was approved by a vote of at least two-thirds of
the directors then still in office who were directors at the beginning of the
period, become a majority of the Board of Directors.

Amendment or Termination of Employee Stock Purchase Plan. The Board of
Directors may at any time terminate or amend, modify or suspend the Employee
Stock Purchase Plan, provided that without stockholder approval there shall be
no: (i) material increase in the benefits accruing to participants under the
Employee Stock Purchase Plan or "modifications" within the meaning of Section
424 of the Code if the increase in benefits or modifications would adversely
affect the availability of the provisions of Section 16(b) of the Exchange Act
or the qualification of the Employee Stock Purchase Plan as an employee stock
purchase plan under Section 423 of the Code; (ii) change in the number of
shares of Common Stock that may be issued under the Employee Stock Purchase
Plan, except in the event of a change in capital structure of the Company;
(iii) change in the class of person eligible to participate in the Employee
Stock Purchase Plan; or (iv) other change in the Employee Stock Purchase Plan
that requires stockholder approval under applicable law. No amendment will
adversely affect outstanding options without the consent of the optionee and
the termination of the Employee Stock Purchase Plan will not terminate options
then outstanding, without the consent of the participant. Notwithstanding the
preceding sentence, the Board of Directors shall have the power to make any
changes to the Employee Stock Purchase Plan that may, in the opinion of counsel
for the Company, be necessary or appropriate from time to time to enable it and
any option granted thereunder to qualify as an employee stock purchase plan
under Section 423 of the Code so as to receive preferential federal income tax
treatment. In the event the Company is no longer publicly held, at its option,
the Company may terminate the Employee Stock Purchase Plan and upon the
termination, outstanding options shall be cancelled and each participant shall
receive in cash an amount equal to the accumulated payroll deductions credited
to the participant's account immediately prior to termination. Unless the
Employee Stock Purchase Plan is terminated earlier, it will terminate on August
31, 2003.

17
<PAGE>

The following description of the federal income tax consequences of the
Employee Stock Purchase Plan is general and does not purport to be complete. In
addition, the description does not discuss the tax consequences arising as a
result of the participant's death or of the tax consequences of the Employee
Stock Purchase Plan under the laws of any state or foreign country in which the
participant may reside.

Federal Income Tax Consequences of the Employee Stock Purchase Plan. The
Employee Stock Purchase Plan is intended to constitute an employee stock
purchase plan under Section 423 of the Code. As presently in effect, under
Section 423 of the Code, a participant will not realize income as a result of
either the grant of an option to acquire Common Stock as of an Offering Date or
the acquisition of Common Stock by exercise of the option as of the Exercise
Date. If the participant does not dispose of the Common Stock before the
earlier of two years after the Offering Date or one year after the Exercise
Date, then upon the subsequent sale of the Common Stock, he or she will have
ordinary compensation income of the lesser of 15% of the fair market value of
the Common Stock as of the Offering Date or the excess, if any, of the selling
price of the Common Stock over the Option Price. Any additional gain or loss
will be treated as short-term or long-term capital gain or loss, depending on
the holding period. The Company is not entitled to an income tax deduction with
respect to the ordinary compensation income described above. If the participant
disposes of the stock before the earlier of two years after the Offering Date
or one year after the Exercise Date, then the excess, if any, of the fair
market value of the Common Stock on the Exercise Date over the Option Price
will be ordinary compensation income to the participant, and the Company will
be entitled to a deduction with respect to that income. Any additional gain or
loss will be treated as short-term or long-term capital gain or loss, depending
on the holding period.

Required Vote

The affirmative vote of holders of a majority of the shares cast at the
Annual Meeting is required to approve the adoption of the Employee Stock
Purchase Plan.

The Board of Directors recommends that the stockholders vote FOR the
proposal to adopt the Employee Stock Purchase Plan.

ITEM 3
AMENDMENT OF THE COMPANY'S STOCK INCENTIVE PLAN TO INCREASE
THE NUMBER OF SHARES RESERVED FOR ISSUANCE THEREUNDER

By resolutions adopted as of March 23, 1998, the Board of Directors
approved, and voted to recommend that the stockholders approve, an amendment to
the Stock Incentive Plan to increase the number of shares of Common Stock
authorized for issuance under the Stock Incentive Plan from 1,400,000 to
2,000,000.

The Board of Directors believes that equity interests are a significant
factor in the Company's ability to attract, retain and motivate key employees,
Directors and consultants that are critical to the Company's long-term success
and that an increase in the number of shares available for issuance under the
Stock Incentive Plan is necessary in order to provide key employees, Directors
and consultants of the Company with incentives to serve the Company. In
approving the increase in the number of shares reserved for issuance under the
Stock Incentive Plan, the Board of Directors considered the significant
increase in the scale of the Company that occurred during 1997 and the
corresponding growth in the number of the Company's employees. The Board of
Directors also considered the total number of shares of Common Stock that would
be outstanding after the Company's recent equity offering, which is
approximately 19,000,000 shares, or approximately 21,000,000 shares on a fully
diluted basis including the 2,000,000 shares reserved for issuance under the
Stock Incentive Plan.

At the 1997 Annual Meeting, the Iron Mountain stockholders approved an
increase in the number of shares of Common Stock authorized for issuance under
the Stock Incentive Plan from 1,000,000 to 1,400,000. Some of the acquisitions
completed by the Company since the 1997 Annual Meeting involved the issuance of
Common Stock

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and options to acquire shares of Common Stock. During 1997, at the time of
consummation of the acquisitions, the Company issued options to employees of
acquired companies to purchase approximately 146,000 shares of Common Stock to
replace options held by the acquired companies' employees to purchase such
companies' common stock. Such options were accounted for as additional purchase
price based on the fair value of the options at the dates of the acquisitions,
using an option pricing model.

In addition, as a result of the Company's acquisition of Arcus Group, the
Company succeeded to two option plans of Arcus Group, pursuant to which options
to purchase 589,957 shares of Common Stock are outstanding. These two plans,
entitled the Iron Mountain/ATSI 1995 Stock Option Plan and the Iron
Mountain/UAC 1995 Stock Option Plan (collectively, the "Arcus Plans"), amended
and restated the former Arcus Plans. All options outstanding under the Arcus
Plans at the time of the acquisition automatically became options to acquire
Common Stock according to a stated formula with appropriate adjustment to the
exercise prices, but retained the same vesting schedules. Approximately 50% of
the options assumed by Iron Mountain as a result of the Arcus Group acquisition
were held by individuals that were not employed by Iron Mountain after the
acquisition. No further options are available for grant under the Arcus Plans.
In approving the merger agreement pursuant to which Iron Mountain acquired
Arcus Group, the Iron Mountain stockholders approved the Arcus Plans. The
outstanding options under the Arcus Plans, which became options to acquire
Common Stock, were accounted for as additional purchase price based on the fair
value of the options at the date of the Arcus Group acquisition using an option
pricing model.

Also, as a result of the Company's acquisitions, it has hired a number of
new employees who were formerly employees of acquired companies or who were
hired to replace those employees or to perform functions directly resulting
from the acquisitions, to whom the Company has made option grants pursuant to
the Stock Incentive Plan as incentive compensation.

More than 45% of the option grants pursuant to the Stock Incentive Plan
since the 1997 Annual Meeting resulted from the Company's acquisitions, either
directly or indirectly, as discussed above. Because the acquisition-related
option grants under the Stock Incentive Plan utilized the options available
under the Stock Incentive Plan at a faster rate than anticipated prior to the
time of the 1997 Annual Meeting and because of the overall increase in the size
of the Company and the number of employees, the stockholders of the Company are
being asked to approve the increase at the Annual Meeting.

As of April 1, 1998, options for an aggregate of 1,119,588 shares of
Common Stock had been granted and were outstanding under the Stock Incentive
Plan at exercise prices ranging from $1.12 to $36.50 per share and 138,439
shares were available for grants of options and Other Rights (as defined below)
under the Stock Incentive Plan. In addition, options to acquire 472,315 shares
of Common Stock were outstanding under the Arcus Plans, and no shares were
available for grants of options thereunder. If the amendment is approved,
738,439 shares of Common Stock will be available for grants of options and
Other Rights under the Stock Incentive Plan. On April 1, 1998, the closing
price per share of the Company's Common Stock, as reported in a summary of
composite transactions in The Wall Street Journal for stocks listed on Nasdaq
National Market, was $37.625.

Stock Option Information

The following is a summary of the Stock Incentive Plan and is subject to
and qualified in its entirety by reference to the complete text of the Stock
Incentive Plan, as amended.

Purpose, Participants, Effective Date and Duration. The purpose of the
Stock Incentive Plan is to encourage key employees, Directors and consultants
of the Company and its Subsidiaries who render services of special importance
to, and who have contributed or may be expected to contribute materially to the
success of, the Company or a Subsidiary to continue their association with the
Company and its Subsidiaries by providing favorable opportunities for them to
participate in the ownership of the Company and in its future growth through
the granting of shares ("Restricted Stock"), options, SARs and other rights to
compensation in amounts determined by the value

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of the Common Stock. Restricted Stock, SARs and other rights are referred to
collectively as "Other Rights." The Stock Incentive Plan will terminate on
November 26, 2005, unless earlier terminated by the Board of Directors, and
awards made prior to termination will not be affected by the termination.

Shares Subject to the Stock Incentive Plan. The total number of shares of
Common Stock that may be subject to options and Other Rights under the Stock
Incentive Plan (the "Reserved Shares") may not exceed 1,400,000. However, if
approved by the stockholders, the number of Reserved Shares will be increased
to 2,000,000. In the event of any change in the number or kind of Common Stock
outstanding pursuant to a reorganization, recapitalization, exchange of shares,
stock dividend or split or combination of shares, appropriate adjustments to
the Reserved Shares and the number of shares subject to outstanding grants or
awards, in the exercise price per share of outstanding options and in the kind
of shares that may be distributed under the Stock Incentive Plan will be made.
The total amount of Reserved Shares that may be granted to any single employee
under the Stock Incentive Plan may not exceed in the aggregate 250,000.
However, if approved by the stockholders, the number of Reserved Shares that
may be granted to any single employee will be increased to 350,000. To the
extent that an award under the Stock Incentive Plan lapses or is forfeited, any
shares subject to such award will again become available for grant under the
terms of the Stock Incentive Plan.

Administration. The Stock Incentive Plan may be administered by the Board
of Directors or, at the Board of Director's discretion, by the Option Plan
Subcommittee. Currently, the Option Plan Subcommittee, which is a subcommittee
of the Compensation Committee of the Board of Directors, administers the Stock
Incentive Plan. Each member of the Option Plan Subcommittee must (i) so long as
Section 16 of the Exchange Act is applicable to the Company, be a "non-employee
director" or the equivalent within the meaning of Rule 16b-3 under the Exchange
Act and (ii) so long as Section 162(m) of the Code is applicable to the
Company, be an "outside director" within the meaning of Section 162(m) of the
Code and the regulations thereunder.

Subject to the terms of the Stock Incentive Plan, the Option Plan
Subcommittee has authority to: (i) select the persons to whom options and Other
Rights shall be granted; (ii) determine the number or value and the terms and
conditions of options or Other Rights granted to each such person, including
the price per share to be paid upon exercise of any option, the period within
which each such option or Other Right may be exercised and the manner of
exercise; and (iii) interpret the Stock Incentive Plan and prescribe rules and
regulations for the administration thereof.

Stock Options. The Option Plan Subcommittee may grant awards to
participants in the form of options. With regard to each option, the Option
Plan Subcommittee determines whether the option is intended to be an incentive
stock option (an "ISO") within the meaning of Section 422 of the Code or a
non-qualified stock option (an "NSO"). In the case of an ISO, the exercise
price may not be less than the "fair market value" of the Reserved Shares on
the date the option is granted; provided, however, that in the case of an
employee who owns (or is considered to own under Section 424(d) of the Code)
stock possessing more than ten percent of the total combined voting power of
all classes of stock of the Company or any of its Subsidiaries, the price at
which Common Stock may be purchased pursuant to an ISO may not be less than
110% of the fair market value of the Common Stock on the date the ISO is
granted.

An ISO cannot be exercisable after the expiration of ten years after the
date of grant. In the case of any employee who owns (or is considered under
Section 424(d) of the Code as owning) stock possessing more than ten percent of
the total combined voting power of all classes of stock of the Company or any
of its Subsidiaries, no ISO shall be exercisable after the expiration of five
years from its date of grant.

The option exercise price may be paid in cash, in shares of Common Stock
owned by the optionee, by delivery of a recourse promissory note secured by the
Common Stock acquired upon exercise of the option or by means of a "cashless
exercise" procedure in which a broker transmits to the Company the exercise
price in cash, either

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<PAGE>

as a margin loan or against the optionee's notice of exercise and confirmation
by the Company that it will issue and deliver to the broker stock certificates
for that number of Reserved Shares having an aggregate fair market value equal
to the exercise price or agrees to pay the option price to the Company in cash
upon its receipt of stock certificates. In its discretion, the Option Plan
Subcommittee may grant a new option to purchase the number of shares of Common
Stock delivered to the Company in full or partial payment of the option price,
or in full or partial payment of the tax withholding obligations resulting from
the exercise of any option.

Stock Appreciation Rights. The Option Plan Subcommittee may grant SARs to
participants as to such number of Reserved Shares and on such terms and
conditions as it may determine. SARs may be granted separately or in connection
with ISOs or NSOs. Upon exercise of an SAR, the holder is entitled to receive
payment equal to the excess of the fair market value, on the date of exercise,
of the number of Reserved Shares for which the SAR is exercised, over the
exercise price for such Reserved Shares under a related option, or if there is
no related option, over an amount per share stated in the written agreement
setting forth the terms and conditions of the SAR. Payment may be made in cash
or other property, including Common Stock, in accordance with the provisions of
an SAR agreement. Upon the exercise of an SAR related to an option, the option
terminates as to the number of Reserved Shares for which the SAR is exercised.

Restricted Stock. The Option Plan Subcommittee may grant to participants a
number of shares of Restricted Stock determined in its discretion, subject to
terms and conditions so determined by it, including conditions that may require
the holder to forfeit the Common Stock in the event that the holder ceases to
provide services to the Company or a Subsidiary before a stated time. Unlike
holders of options and SARs, a holder of Restricted Stock has the rights of a
stockholder of the Company to vote and to receive payment of dividends on the
Restricted Stock, unless the Option Plan Subcommittee specifies to the contrary
in the restricted stock agreement setting forth the terms on which the
Restricted Stock is granted.

Special Bonus Awards. The Company may grant in connection with any NSO or
grant of Restricted Stock a special cash bonus in an amount not to exceed the
lesser of: (i) the combined federal, state and local income tax liability
incurred by the optionee as a consequence of the acquisition of stock pursuant
to the exercise of the NSO or the grant or vesting of the Restricted Stock, and
the related special bonus; or (ii) 30% of the imputed income realized by the
optionee on account of such exercise or vesting, and the related special bonus.
A grant may also provide that the Company will lend an optionee an amount not
more than the amount described in the preceding sentence, less the amount of
any special cash bonus.

Forfeiture for Dishonesty. If the Board of Directors determines that a
participant has engaged in fraud, embezzlement, theft, commission of a felony
or proven dishonesty in the course of his or her employment that has damaged
the Company or has disclosed trade secrets or other proprietary information of
the Company (a) the participant shall forfeit all unexercised options and all
exercised options under which the Company has not yet delivered certificates
and (b) the Company shall have the right to repurchase all or any part of the
shares of Common Stock acquired by the participant upon the earlier exercise of
any option, at a price equal to the amount paid to the Company upon exercise,
together with interest as determined pursuant to the terms of the Stock
Incentive Plan.

Noncompetition Restrictions. Every participant is required to enter into a
noncompetition agreement with the Company. The noncompetition agreement
provides generally that, for a period of two years following termination of
employment with the Company, an employee cannot work in the records management
industry at a competitor located within 50 miles of the Iron Mountain facility
where the employee worked. All option agreements currently provide that options
may not be exercised if at the time of exercise the optionee is in violation of
the noncompetition agreement (the Option Plan Subcommittee may, in its
discretion and without stockholder approval, waive this restriction or elect
not to include it in future option agreements). The Option Plan Subcommittee
may also, and presently does, provide in any stock option agreement that if an
optionee accepts employment with a competitor within two years after the date
of exercise of all or any portion of an option, the participant shall pay to
the Company

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<PAGE>

an amount equal to the excess of the fair market value of the shares as to
which the option was exercised on that date, over the price paid for such
shares. The Option Plan Subcommittee may, in its discretion and without
stockholder approval, release the participant from this repayment requirement
if the Option Plan Subcommittee determines that the participant's acceptance of
employment with a competitor is not adverse to the interests of the Company.

The following description of the federal income tax consequences of
options and Other Rights is general and does not purport to be complete. In
addition, the description does not discuss the tax consequences arising as a
result of a participant's death or of the tax consequences of options and Other
Rights under the laws of any state or foreign country in which the participant
may reside.

Tax Treatment of Options. A participant realizes no taxable income when an
NSO is granted. Instead, the difference between the fair market value of the
Common Stock subject to the NSO and the exercise price paid is taxed as
ordinary compensation income when the NSO is exercised. The difference is
measured and taxed as of the date of exercise, if the stock is not subject to a
"substantial risk of forfeiture," or as of the date or dates on which the risk
terminates in other cases. A participant may elect to be taxed on the
difference between the exercise price and the fair market value of the Common
Stock on the date of exercise, even though some or all of the Common Stock
acquired is subject to a substantial risk of forfeiture. Gain on the subsequent
sale of the Common Stock is taxed as capital gain. The Company receives no tax
deduction on the grant of a NSO, but is entitled to a tax deduction when the
participant recognizes taxable income on or after exercise of the NSO, in the
same amount as the income recognized by the optionee.

Generally, a participant incurs no federal income tax liability on either
the grant or the exercise of an ISO, although a participant will generally have
taxable income for alternative minimum tax purposes at the time of exercise
equal to the excess of the fair market value of the stock acquired over the
exercise price. If the shares of Common Stock are held for at least one year
after the date of exercise of the related ISO and at least two years after its
date of grant, any gain realized on subsequent sale of the stock will be taxed
as long-term capital gain. If the stock is disposed of within a shorter period
of time, the participant will be taxed as if the participant had then received
ordinary compensation income in an amount equal to the difference between the
fair market value of the stock on the date of exercise of the ISO and its fair
market value on its date of grant. The Company receives no tax deduction on the
grant or exercise of an ISO, but is entitled to a tax deduction if the
participant recognizes taxable income on account of a premature disposition of
ISO stock, in the same amount and at the same time as the participant's
recognition of income.

Tax Treatment of SARs. A recipient incurs no imputed income upon the grant
of an SAR, but upon its exercise realizes ordinary compensation income in an
amount equal to the cash or cash equivalent that he received at that time. If
the recipient receives shares of Common Stock upon exercise of the SAR, the
recipient incurs imputed income measured by the difference between the base
amount set forth in the SAR agreement and the fair market value of the Common
Stock at the exercise date (or, if at the exercise date the stock is subject to
a substantial risk of forfeiture, at the date or dates on which the risk
expires).

Tax Treatment of Restricted Stock. A person who receives a grant of
Restricted Stock generally will not recognize taxable income at the time the
award is received, but will recognize ordinary compensation income when
restrictions constituting a substantial risk of forfeiture lapse. (If the grant
is made without any restrictions, the participant will immediately recognize
ordinary compensation income.) The amount of imputed income will be equal to
the excess of the aggregate fair market value, as of the date the restrictions
lapse, over the amount (if any) paid by the holder for the Restricted Stock.
Alternatively, a recipient of Restricted Stock may elect to be taxed on the
excess of the fair market value of the Restricted Stock at the time of grant
over the amount (if any) paid by the recipient for the Restricted Stock,
notwithstanding the restrictions on the stock. All such taxable amounts are
deductible by the Company at the time and in the amount of the ordinary
compensation income recognized by the recipient of the Restricted Stock.

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<PAGE>

Parachute Payments. Under certain circumstances, an accelerated vesting or
the cash out of options or Other Rights in connection with a Change of Control
(as defined above in "Adoption of the Employee Stock Purchase Plan--Change in
Capital Structure") of the Company might be deemed an "excess parachute
payment" for purposes of the golden parachute tax provisions of Section 280G of
the Code. To the extent it is so considered, a participant may be subject to a
20% excise tax and the Company may be denied an income tax deduction.

Effect of Certain Corporate Transactions. If the Company merges or
consolidates with one or more corporations (whether or not the Company is the
surviving corporation) while unexercised options or SARs remain outstanding
under the Stock Incentive Plan, or if the Company is liquidated or sells or
otherwise disposes of substantially all of its assets to another entity, or
upon a Change of Control (any of these events is hereafter referred to as a
"Transaction"), then, except as otherwise specifically provided to the contrary
in any applicable agreement, the Option Plan Subcommittee, in its discretion,
may amend the terms of all outstanding options and SARs so that either: (i) the
participants shall be given an opportunity to exercise all outstanding options
and SARs according to their terms during the period of 20 days ending on the
day preceding the effective date of the Transaction, and any options and SARs
that are still outstanding and unexercised as of the effective date of the
Transaction shall be cancelled; (ii) after the effective date of the
Transaction, each participant shall be entitled, upon exercise of an option or
SAR, to receive in lieu of shares of Common Stock the number and class of
shares of such stock or other securities to which such person would have been
entitled pursuant to the terms of the Transaction as the holder of record of
the number of shares of Common Stock as to which the option or SAR is being
exercised, or shall be entitled to receive from the successor entity a new
stock option or stock appreciation right of comparable value; or (iii) all
outstanding options and SARs shall be cancelled as of the effective date of the
Transaction and the participant shall receive cash or other consideration with
a value equal to the value of the shares the optionee would have received had
the option then been exercised (to the extent exercisable). If the Option Plan
Subcommittee adopts the course of action described in clause (i) of the
preceding sentence, it may, in its sole discretion, accelerate the vesting of
an option or SAR that is not immediately exercisable. Upon the occurrence of a
"Limited Change of Control", as defined in "Executive Compensation--Change of
Control Arrangement" above, the vesting of options and SARs will automatically
accelerate and the options and SARs will fully convert. Each holder of options
and SARs will be entitled to receive upon exercise of his or her options and
SARs the number and class of shares of stock or other securities and any other
consideration of the surviving or resulting corporation that the optionee would
have been entitled to receive pursuant to the merger or consolidation had the
optionee held the shares of Common Stock subject to the option or SAR.

Amendments to Stock Incentive Plan. The Board of Directors may modify,
revise or terminate the Stock Incentive Plan at any time and from time to time,
except that approval of the stockholders of the Company is required with
respect to any amendment that changes the aggregate number of Reserved Shares
that may be issued under options or granted pursuant to the Stock Incentive
Plan, changes the class of employees or other persons eligible to receive
options or Other Rights, reduces the exercise price of any ISO, extends the
latest date on which an ISO can be exercised, increases materially the benefits
accruing to any person under the Stock Incentive Plan, or makes any other
change that requires stockholder approval under applicable law.

Required Vote

The affirmative vote of holders of a majority of the shares cast at the
Annual Meeting is required to approve the amendment of the Stock Incentive Plan
to increase the number of shares of Common Stock issuable thereunder from
1,400,000 to 2,000,000.

The Board of Directors recommends that the stockholders vote FOR the
approval of the amendment to the Stock Incentive Plan.

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<PAGE>

ITEM 4
AMENDMENT OF THE COMPANY'S STOCK INCENTIVE PLAN TO INCREASE
THE TOTAL NUMBER OF SHARES OF COMMON STOCK WITH RESPECT TO
WHICH OPTIONS AND OTHER RIGHTS MAY BE GRANTED TO ANY SINGLE EMPLOYEE

By resolutions adopted as of March 23, 1998, the Board of Directors
approved, and voted to recommend that the stockholders approve, an amendment to
Section 3 of the Company's Stock Incentive Plan to increase the number of
shares with respect to which options and Other Rights may be granted thereunder
to any single employee from 250,000 to 350,000.

The Board of Directors believes that equity interests are a significant
factor in the Company's ability to attract, retain and motivate key employees,
Directors and consultants that are critical to the Company's long-term success
and that an increase in the number of shares with respect to which options and
Other Rights may be granted under the Stock Incentive Plan to any single
employee is necessary in order to provide key employees, Directors and
consultants of the Company with continuing incentives to serve the Company.
There are currently no employees who hold options and Other Rights covering
shares in excess of 250,000; however, certain employees may reach that level if
the Company grants options and Other Rights at rates consistent with past
practice.

The employee limit of 250,000 shares was enacted in part to satisfy the
requirements of Section 162(m) of the Code, which limits the amount of the
Company's deduction for compensation paid to the Chief Executive Officer and
certain other executive officers to $1,000,000 per person. One exception to the
limit provides that income recognized on the exercise of an option will
generally be fully deductible, and will not be added to other compensation
income in applying the $1,000,000 limit, if the grant is made by a committee of
outside directors, the plan pursuant to which the option is granted states the
maximum number of shares with respect to which options may be granted, and the
exercise price of the option is the fair market value of the stock at the time
the option is granted. Increasing the employee limit from 250,000 to 350,000
will also ensure that the compensation deduction limitation of Section 162(m)
of the Code will not prevent the Company from taking an otherwise allowable
deduction for income recognized on the exercise of an option.

Required Vote

The affirmative vote of holders of a majority of the shares cast at the
Annual Meeting is required to approve the amendment of the Stock Incentive Plan
to increase the number of shares with respect to which options and Other Rights
may be granted thereunder to any single employee from 250,000 to 350,000.

The Board of Directors recommends that the stockholders vote FOR the
approval of the amendment to the Stock Incentive Plan.

ITEM 5
RATIFICATION OF SELECTION OF INDEPENDENT PUBLIC ACCOUNTANTS

Subject to ratification by the stockholders, the Board of Directors has
selected the firm of Arthur Andersen LLP as the Company's independent public
accountants for the current year. Arthur Andersen LLP has served as the
Company's independent public accountants since 1988.

Representatives of Arthur Andersen LLP are expected to be present at the
Annual Meeting. They will have the opportunity to make a statement if they
desire to do so and will also be available to respond to appropriate questions
from stockholders.

If the stockholders do not ratify the selection of Arthur Andersen LLP as
the Company's independent public accountants, the selection of accountants will
be reconsidered by the Board of Directors.

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Required Vote

The affirmative vote of holders of a majority of the shares cast at the
Annual Meeting is required to ratify the selection of Arthur Andersen LLP to
serve as the Company's independent public accountants for the current fiscal
year.

The Board of Directors recommends that the stockholders vote FOR the
ratification of the selection of Arthur Andersen LLP.

ADDITIONAL INFORMATION

Other Matters

The Board of Directors does not know of any other matters that may come
before the Annual Meeting. However, if any other matters are properly presented
to the meeting, it is the intention of the persons named in the accompanying
proxy to vote, or otherwise act, in accordance with their best judgment on such
matters.

Section 16(a) Beneficial Ownership Reporting Compliance

Section 16(a) of the Exchange Act requires the Company's officers and
Directors, and persons who own more than ten percent of a registered class of
the Company's equity securities, to file reports of ownership on Form 3 and
changes in ownership on Form 4 or 5 with the Securities and Exchange Commission
(the "SEC"). Such officers, Directors and ten percent stockholders are also
required by SEC rules to furnish the Company with copies of all Section 16(a)
reports they file. Based solely on its review of the copies of such forms
received by it, or written representation from certain reporting persons that
they were not required to file a Form 5, the Company believes that, during the
fiscal year ended December 31, 1997, its officers, Directors and ten percent
stockholders complied with all Section 16(a) filing requirements applicable to
such persons, except that: B. Thomas Golisano, a Class A Director of the
Company, filed a statement of changes in beneficial ownership on Form 4
pertaining to several gift transactions late; Arthur D. Little, a Class B
Director of the Company, filed a statement of changes in beneficial ownership
on Form 4 pertaining to a transaction by a trust whose shares he disclaims
beneficial ownership late and John F. Kenny, Jr., Harold E. Ebbighausen and
Christopher Neefus, each an officer of the Company, filed their initial
statements of beneficial ownership of securities on Form 3 late.

Proposals of Stockholders

The Company expects to hold its 1999 Annual Meeting on May 27, 1999. A
stockholder who intends to present a proposal at the 1999 Annual Meeting of
Stockholders for inclusion in the Company's 1999 proxy statement and proxy card
relating to that meeting must submit the proposal by January 27, 1999. In order
for the proposal to be included in the proxy statement, the stockholder
submitting the proposal must meet certain eligibility standards and comply with
certain procedures established by the SEC, and the proposal must comply with
the requirements as to form and substance established by applicable laws and
regulations. The proposal must be mailed to the Company's principal executive
office, at the address stated herein, and should be directed to the attention
of the Chief Financial Officer.

By Order of the Board of Directors

JAS. MURRAY HOWE, Secretary

April 23, 1998

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EXHIBIT A

IRON MOUNTAIN INCORPORATED
1998 EMPLOYEE STOCK PURCHASE PLAN

1. PURPOSE

The purpose of this 1998 Employee Stock Purchase Plan (the "Plan") is to
provide employees of Iron Mountain Incorporated (the "Company") and its
Subsidiaries the opportunity to acquire a proprietary interest in the Company
by providing favorable terms for them to purchase its stock. This Plan is
intended to qualify as an employee stock purchase plan within the meaning of
Section 423 of the Code.

2. DEFINITIONS

(a) "Compensation" shall mean the amount reported (or to be reported) in
Box 1 of Form W-2, or its equivalent, increased by any salary reduction elected
pursuant to Sections 402(g) or 125 of the Code.

(b) "Board" shall mean the Board of Directors of the Company.

(d) "Committee" shall have the meaning set forth in Section 3.

(e) "Common Stock" shall mean the shares of the Company's common stock,
$0.01 par value per share.

(f) "Employee" shall mean any individual who is customarily employed for
more than twenty hours per week and more than five months in a calendar year by
the Company or any Subsidiary. The term Employee shall not include: (i) any
individual who is not a common law employee of the Company or a Subsidiary; (ii)
any Employee who owns, directly or indirectly, as of the Offering Date five
percent or more of the Company or a Subsidiary; and (iii) any Employee who is a
member of a collective bargaining unit with which the Company or a Subsidiary
has bargained in good faith with respect to participation in the Plan and as a
result of such bargaining the labor organization made an affirmative decision
not to participate in the Plan.

(g) "Exercise Date" shall, unless changed by the Committee, mean August 31,
1999 and each August 31 thereafter while the Plan remains in effect; provided,
however, that if August 31 is not a business day, the Exercise Date shall be the
business day immediately preceding August 31.

(h) "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended.

(i) "Fair Market Value" shall be determined according to the following
rules: (i) if the Common Stock is not at the time listed or admitted to trading
on a stock exchange or the Nasdaq National Market, the fair market value shall
be the closing price of the Common Stock on the date in question in the
over-the-counter market, as such price is reported in a publication of general
circulation selected by the Board and regularly reporting the price of the
Common Stock in such market; provided, however, that if the price of the Common
Stock is not so reported, the fair market value shall be determined in good
faith by the Board, which may take into consideration (1) the price paid for the
Common Stock in the most recent trade of a substantial number of shares known to
the Board to have occurred at arm's length between willing and knowledgeable
investors, or (2) an appraisal by an independent party, or (3) any other method
of valuation undertaken in good faith by the Board, or some or all of the above
as the Board shall in its discretion elect; or (ii) if the Common Stock is at
the time listed or admitted to trading on any stock exchange or the Nasdaq
National Market, then the fair market value shall be the mean between the lowest
and highest reported sale prices (or the lowest reported bid price and the
highest reported asked price) of the Common Stock on the date in question on the
principal exchange on which the Common Stock is then listed or admitted to
trading. If no reported sale of Common Stock takes place on the date in question
on the principal exchange or

A-1
<PAGE>

the Nasdaq National Market, as the case may be, then the reported closing sale
price (or the reported closing asked price) of the Common Stock on such prior
date on the principal exchange or the Nasdaq National Market, as the case may
be, shall be determinative of fair market value.

(j) "Insider" shall mean a person subject to Section 16 of the Exchange
Act.

(k) "Offering" shall mean any offering of Common Stock in accordance with
Section 7.

(l) "Offering Date" shall, unless changed by the Committee, mean September
1, 1998 and each September 1 thereafter while the Plan remains in effect;
provided, however, that if September 1 is not a business day, the Offering Date
shall be the business day immediately preceding September 1.

(m) "Option" shall mean the right of a Participant to purchase Common Stock
pursuant to an Offering.

(n) "Option Price" shall have the meaning set forth in Section 8.

(o) "Optionee" shall mean any individual who has been granted an Option
that remains outstanding under the terms of any Offering or who owns Common
Stock as a result of an Offering.

(p) "Participant" shall mean an Employee who has in effect a payroll
deduction authorization in accordance with Section 6.

(q) "Securities Act" shall mean the Securities Act of 1933, as amended.

(r) "Subsidiary" shall mean a corporation of which the Company owns,
directly or indirectly through an unbroken chain of ownership, fifty percent or
more of the total combined voting power of all classes of stock, whether or not
such corporation now exists or is hereafter organized or acquired by the Company
or a Subsidiary.

3. ADMINISTRATION OF THE PLAN

The Plan shall be administered by the Board or, in the discretion of the
Board, a committee composed of at least two individuals who may be members of
the Board or employees of the Company or a Subsidiary (the "Committee"). In the
event that a vacancy on the Committee occurs on account of the resignation of a
member or the removal of a member by vote of the Board, a successor member
shall be appointed by vote of the Board. No member of the Committee shall be
liable for any action or determination made in good faith with respect to the
Plan. All references in the Plan to the "Committee" shall be understood to
refer to the Committee or the Board, whoever shall administer the Plan.

The Committee shall select one of its members as Chairman and shall hold
meetings at such times and places as it may determine. A majority of the
Committee shall constitute a quorum, and acts of the Committee at which a
quorum is present, or acts reduced to or approved in writing by all the members
of the Committee, shall be the valid acts of the Committee. The Committee shall
have the authority to adopt, amend and rescind such rules and regulations as,
in its opinion, may be advisable in the administration of the Plan. All
questions of interpretation and application of such rules and regulations, of
the Plan and of Options granted thereunder shall be subject to the
determination of the Committee, which shall be final and binding.

The Committee shall have the authority, without the need for further
approval, to establish a different Offering Date and/or Exercise Date, to
modify the amount of time between an Offering Date and an Exercise Date and to
increase the number of Offerings in a year.

With respect to Insiders, transactions under the Plan are intended to
comply with all applicable conditions of Rule 16b-3 or its successor under the
Exchange Act. To the extent any provision of the Plan or action by the Com-

A-2
<PAGE>

mittee fails to so comply, it shall be deemed to be modified so as to be in
compliance with such Rule, or, if such modification is not possible, it shall
be deemed to be null and void, to the extent permitted by law and deemed
advisable by the Committee.

4. OPTION SHARES

The total amount of Common Stock with respect to which Options may be
granted under the Plan shall not exceed in the aggregate 250,000 shares from
either authorized but unissued shares or treasury shares; provided, however,
that such aggregate number of shares shall be subject to adjustment in
accordance with Section 16. If any outstanding Option expires for any reason,
or terminates by reason of the severance of employment of the Participant or
any other cause, or is surrendered, the shares of Common Stock allocable to the
unexercised portion of the Option may again be made subject to an Option under
the Plan.

5. ELIGIBILITY

An Employee shall be eligible to become a Participant in the Plan on any
Offering Date on which he is employed by the Company or a Subsidiary; provided,
however, that no Employee shall be granted an Option:

(i) if immediately after the grant the aggregate amount of stock that
he would own, or would be considered to own under Section 424(d)
of the Code, or would hold outstanding options to purchase, would
represent five percent or more of the total combined voting power
or value of all classes of capital stock of the Company or of any
Subsidiary; or

(ii) that permits his right to purchase shares under all employee
stock purchase plans (within the meaning of Section 423 of the
Code) of the Company and its Subsidiaries to accrue at a rate
that exceeds $25,000 for any calendar year, determined by
reference to the Fair Market Value of the shares at the time the
Option is granted.

6. PARTICIPATION

(a) An Employee may become a Participant in any future Offering by
completing an authorization for payroll deductions in connection with the
Offering at such time (prior to the Offering Date) and in such manner as the
Committee may prescribe. Payroll deductions pursuant to an authorization shall
commence with the payroll period in which the Offering Date occurs and shall end
with the last payroll completed prior to the Exercise Date for the Offering to
which the authorization applies, unless the authorization is sooner terminated
by the Participant as provided in Section 10. The Committee may provide that in
the case of the first Offering, payroll deductions shall commence with the first
payroll period ending after the initial Offering Date. All payroll deductions
shall be made on an after-tax basis.

(b) A Participant shall elect in his authorization for payroll deduction to
have deductions made from his Compensation on each payday in an amount equal to
a whole percentage of from one to fifteen percent of his Compensation. All
payroll deductions made for a Participant shall be credited to a bookkeeping
account maintained for him under the Plan. In no event shall interest be paid to
a Participant with respect to payroll deductions credited to his account,
whether such deductions are used in connection with the exercise of an Option or
are returned to the Participant or his estate in cash.

(c) Except as may be required by law, a Participant may not make any
payments to his account other than by his authorization for payroll deduction. A
Participant may elect to decrease his payroll deduction rate at such time and in
such manner as the Committee may prescribe. In no event shall a Participant
increase the amount of his payroll deductions during an Offering. A Participant
may discontinue his participation in the Offering as provided in Section 10.

A-3
<PAGE>

7. GRANT OF OPTIONS

(a) Options under the Plan shall be granted in a series of Offerings, the
first of which shall begin on September 1, 1998. Successive Offerings shall
begin on each Offering Date thereafter until all of the shares of Common Stock
available under the Plan are exhausted or until the Plan is terminated pursuant
to Section 19 or Section 20. Participation by an Employee in any Offering shall
neither limit nor require his participation in any other Offering.

(b) Each Participant in an Offering shall be granted, as of the applicable
Offering Date, an Option to purchase that number of whole shares of Common Stock
that the accumulated payroll deductions credited to his account during the
Offering is able to purchase at the Option Price.

(c) If the total number of shares for which Options are to be granted as of
any Offering Date exceeds the number of shares then available under the Plan,
the Committee shall make a pro rata allocation of the available shares in a
manner as nearly uniform as practicable, and as it shall determine to be
equitable. In that event, the payroll deductions made or to be made pursuant to
authorizations for that Offering shall be reduced accordingly, and the Committee
shall give written notice of such reduction to each affected Participant.

(d) In no event shall a Participant be granted an Option in any Offering to
acquire more than that number of whole shares of Common Stock equal to $25,000
divided by the Fair Market Value of the shares as of the Offering Date;
provided, however, that such limit shall be subject to adjustment in accordance
with Section 16.

8. OPTION PRICE

The Option Price of shares of Common Stock for any Offering shall be the
lesser of: (a) eighty-five percent of the Fair Market Value of the shares on the
Offering Date; or (b) eighty-five percent of the Fair Market Value of the shares
on the Exercise Date.

9. EXERCISE OF OPTIONS

(a) A Participant's Option for an Offering will be exercised automatically
as of the Exercise Date for the Offering to purchase that number of whole shares
of Common Stock equal to the accumulated payroll deductions credited to his
account as of the Exercise Date divided by the Option Price.

(b) A Participant may elect prior to the Exercise Date at such time and in
such manner as the Committee may prescribe to receive in cash an amount equal to
the accumulated payroll deductions in his account on the Exercise Date, rather
than exercising his Option.

(c) As promptly as practicable after each Exercise Date the Company shall
deliver to each Participant in the Offering, in accordance with his election,
either (a) the shares purchased upon the exercise of his Option, together with a
cash payment equal to the balance of any payroll deductions credited to his
account during the Offering that were not used for the purchase of shares, other
than amounts representing fractional shares, or (b) a cash payment equal to the
total of the payroll deductions credited to his account during the Offering.
Amounts representing fractional shares will, at the discretion of the Committee,
either be carried forward for use in the next Offering if the Participant will
participate in that Offering or paid to the Participant in cash.

(d) The shares purchased upon exercise of an Option shall be deemed to be
transferred to the Participant on the Exercise Date.

10. WITHDRAWAL FROM OFFERING

A Participant may at any time prior to the Exercise Date at such time and
in such manner as the Committee may prescribe withdraw from an Offering and
request payment to him of an amount in cash equal to the accumulated

A-4
<PAGE>

payroll deductions credited to his account under the Plan. Such amount will be
paid to the Participant as promptly as practicable after receipt of his request
to withdraw, and no further payroll deductions will be made from his
Compensation with respect to the Offering then in progress and any outstanding
Option shall be cancelled. A Participant's withdrawal from an Offering will
have no effect upon his eligibility to participate in any subsequent Offering
or in any employee stock purchase plan (within the meaning of Section 423 of
the Code) that may hereafter be adopted by the Company or a Subsidiary.

11. EXPIRATION OF OPTIONS ON TERMINATION OF EMPLOYMENT

Options shall not be transferable by a Participant and no amount credited
to a Participant's account may be assigned, transferred, pledged or otherwise
disposed of in any way by a Participant. An Option shall expire unexercised
immediately if a Participant ceases to satisfy the definition of the term
Employee for any reason other than his death and the amount of the accumulated
payroll deductions then credited to his account under the Plan will be paid to
him in cash. Upon termination of the Participant's employment with the Company
or a Subsidiary for any reason other than death, an amount in cash equal to the
accumulated payroll deductions then credited to his account under the Plan will
be paid to him. In the case of a Participant's death, the provisions of Section
17 shall control.

An authorized leave of absence or absence on military or government
service shall not constitute severance of the employment relationship between
the Company or Subsidiary and the Participant for purposes of this Section 11,
provided that either (a) the absence is for a period of no more than ninety
days or (b) the Employee's right to be re-employed after the absence is
guaranteed either by statute or by contract.

12. REQUIREMENTS OF LAW

The Company shall not be required to sell or issue any shares of Common
Stock under the Plan if the issuance of such shares would constitute or result
in a violation by the Optionee or the Company of any provision of any law,
statute or regulation of any governmental authority. Specifically, in connection
with the Securities Act, upon the exercise of any Option the Company shall not
be required to issue shares unless the Board has received evidence satisfactory
to it to the effect that the Optionee will not transfer such shares except
pursuant to a registration statement in effect under the Securities Act or
unless an opinion of counsel satisfactory to the Company has been received by
the Company to the effect that such registration is not required. Any
determination in this connection by the Board shall be final, binding and
conclusive. The Company shall not be obligated to take any affirmative action to
cause the exercise of an Option or the issuance of shares pursuant to an Option
to comply with any laws or regulations of any governmental authority including,
without limitation, the Securities Act or applicable state securities laws.

13. RESTRICTIONS ON TRANSFER

A Participant may not sell, assign, pledge, encumber or otherwise transfer
Common Stock acquired pursuant to the exercise of an Option until the second day
following the first anniversary of the Exercise Date on which the shares were
purchased; provided, however, that the Committee may, in its discretion,
lengthen, shorten or eliminate entirely this restriction. The stock certificate
or certificates evidencing shares of Common Stock issued pursuant to the
exercise of an Option shall bear a legend setting forth any restriction
described in this Section.

14. NO RIGHTS AS STOCKHOLDER

No Participant shall have rights as a stockholder with respect to shares
covered by his Option until the applicable Exercise Date and, except as
otherwise provided in Section 16, no adjustment shall be made for dividends of
which the record date precedes the applicable Exercise Date.

A-5
<PAGE>

15. FORFEITURE FOR DISHONESTY

Notwithstanding anything to the contrary in the Plan, if the Board
determines, after full consideration of the facts presented on behalf of both
the Company and the individual, that a Participant or an Optionee has been
engaged in fraud, embezzlement, theft, commission of a felony or proven
dishonesty in the course of his employment by the Company or a Subsidiary,
which damaged the Company or Subsidiary, or has disclosed trade secrets or
other proprietary information of the Company or a Subsidiary, (a) such
individual's participation in an Offering shall terminate and he shall forfeit
his right to receive any Common Stock pursuant to an Offering that has not yet
been delivered and (b) the Company shall have the right to repurchase all or
any part of the shares of Common Stock acquired by an Optionee upon the earlier
exercise of any Option, at a price equal to the amount paid to the Company upon
such exercise, increased by an amount equal to the interest that would have
accrued in the period between the date of exercise of the Option and the date
of such repurchase upon a debt in the amount of the exercise price, at the
prime rate(s) announced from time to time during such period in the Federal
Reserve Statistical Release Selected Interest Rates. The decision of the Board
as to the cause of a Participant's or Optionee's discharge and the damage done
to the Company or a Subsidiary shall be final, binding and conclusive. No
decision of the Board, however, shall affect in any manner the finality of the
discharge of a Participant or Optionee by the Company or a Subsidiary.

16. CHANGES IN THE COMPANY'S CAPITAL STRUCTURE

(a) In the event that the outstanding shares of Common Stock are hereafter
changed for a different number or kind of shares or other securities of the
Company, by reason of a reorganization, recapitalization, exchange of shares,
stock split, combination of shares or dividend payable in shares or other
securities, a corresponding adjustment shall be made by the Committee in the
number and kind of shares or other securities, and in the Option Price, covered
by outstanding Options, and for which Options may be granted under the Plan;
provided, however, that no adjustment shall be made that would constitute a
modification as defined in Section 424 of the Code. Any such adjustment made by
the Committee shall be conclusive and binding upon all affected persons,
including the Company and all Participants and Optionees.

(b) If while unexercised Options remain outstanding under the Plan the
Company merges or consolidates with a wholly-owned subsidiary for the purpose of
reincorporating itself under the laws of another jurisdiction, the Optionees
will be entitled to acquire shares of Common Stock of the reincorporated Company
upon the same terms and conditions as were in effect immediately prior to such
reincorporation (unless such reincorporation involves a change in the number of
shares or the capitalization of the Company, in which case proportional
adjustments shall be made as provided above), and the Plan, unless otherwise
rescinded by the Board, will remain the Plan of the reincorporated Company.

(c) Except as otherwise provided in the preceding paragraph, if while
unexercised Options remain outstanding under the Plan the Company merges or
consolidates with one or more corporations (whether or not the Company is the
surviving corporation), or is liquidated or sells or otherwise disposes of
substantially all of its assets to another entity, or upon a Change of Control
(as defined herein), then the Committee, in its discretion, shall provide that
either:

(i) after the effective date of such merger, consolidation,
liquidation, sale or Change of Control, as the case may be, each
Optionee shall be entitled, upon exercise of an Option to receive
in lieu of shares of Common Stock the number and class of shares
of such stock or other securities to which he would have been
entitled pursuant to the terms of the merger, consolidation,
liquidation, sale or Change of Control if he had been the holder
of record of the number of shares of Common Stock as to which the
Option is being exercised; or

A-6
<PAGE>

(ii) all outstanding Options shall be exercised as of the day
preceding the effective date of any such merger, consolidation,
liquidation, sale or Change of Control, which day shall be the
Exercise Date for purposes of the Offering; provided, however,
that each Optionee shall be notified of the right to withdraw
from the Offering in accordance with the requirements of Section
10.

(d) A "Change of Control" of the Company shall be deemed to have occurred
if any person (as such term is used in Section 13(d) and 14(d)(2) of the
Exchange Act) other than a trust related to an employee benefit plan maintained
by the Company becomes the beneficial owner (within the meaning of Rule 13d-3
under the Exchange Act) of fifty percent or more of the Company's outstanding
Common Stock, and within the period of twenty-four consecutive months
immediately thereafter, individuals other than (a) individuals who at the
beginning of such period constitute the entire Board of Directors or (b)
individuals whose election, or nomination for election by the Company's
stockholders, was approved by a vote of at least two-thirds of the directors
then still in office who were directors at the beginning of the period, become
a majority of the Board of Directors.

(e) Except as expressly provided to the contrary in this Section 16, the
issuance by the Company of shares of stock of any class for cash or property or
for services, either upon direct sale or upon the exercise of rights or
warrants, or upon conversion of shares or obligations of the Company
convertible into such shares or other securities, shall not affect the number,
class or price of shares of Common Stock then subject to outstanding Options.

17. DISPOSITION OF ACCOUNT AT DEATH

In the event that a Participant dies after the Exercise Date but before
the delivery of the stock certificates, such certificates when issued together
with any cash remaining in the Participant's account shall be transferred to
the Participant's estate. In the event that a Participant dies prior to the
Exercise Date, a payment shall be made to the Participant's estate of an amount
in cash equal to the accumulated payroll deductions credited to the
Participant's account under the Plan; provided, however, that the executor,
administrator or personal representative of the estate of the Participant may
by notice to the Committee in the form and manner prescribed by the Committee
request that the balance of the Participant's account shall be used to exercise
on the Exercise Date the outstanding Option granted prior to the Participant's
death. Any such election by the executor, administrator or personal
representative shall be made not later than the Exercise Date. The Company
shall transfer such shares and any cash remaining in the Participant's account
to the executor, administrator or personal representative of the estate of the
Participant.

18. MISCELLANEOUS

(a) Accumulated payroll deductions and the proceeds from the sale of shares
pursuant to the exercise of Options shall constitute general funds of the
Company.

(b) To the extent required by law, the Company or a Subsidiary shall
withhold or cause to be withheld income and other taxes with respect to any
income recognized by an Optionee by reason of the exercise of an Option. An
Optionee shall agree that if the amount payable to him by the Company and any
Subsidiary in the ordinary course is insufficient to pay such taxes, then he
shall upon request of the Company pay to the Company an amount sufficient to
satisfy its tax withholding obligations.

(c) All notices or other communications by a Participant or Optionee to the
Company pursuant to the Plan shall be deemed to have been given when received in
the form specified by the Company at the location or by the person designated by
the Company for the receipt thereof.

(d) Neither the Plan nor the grant of an Option pursuant to the Plan shall
impose upon the Company or a Subsidiary any obligation to employ or continue to
employ any Participant, and the right of the Company or a Subsidiary to
terminate the employment of any person shall not be diminished or affected by
reason of the fact that an Option has been granted to him.

A-7
<PAGE>

(e) The title of the sections of the Plan are included for convenience only
and shall not be construed as modifying or affecting their provisions. The
masculine gender shall include both sexes; the singular shall include the plural
and the plural the singular unless the context otherwise requires.

(f) The Plan shall be governed by and construed in accordance with the laws
of the Commonwealth of Massachusetts, without regard to the principles of
conflicts of law.

19. AMENDMENT OR TERMINATION OF PLAN

The Board may at any time terminate or from time to time amend, modify or
suspend this Plan (or any part thereof); provided, however, that without the
further approval of the holders of a majority of the outstanding shares of
Common Stock, there shall be no: (a) material increase in the benefits accruing
to Participants under the Plan or any "modifications," as that term is defined
in Section 424 (or its successor) of the Code, if such increase in benefits or
modifications would adversely affect (i) the availability to the Plan of the
protections of Section 16(b) of the Exchange Act, if applicable to the Company,
or (ii) the qualification of the Plan as an employee stock purchase plan within
the meaning of Section 423 of the Code; (b) change in the number of shares of
Common Stock that may be issued under the Plan, except by operation of the
provisions of Section 16; (c) change in the class of persons eligible to
participate in the Plan; or (d) other change in the Plan that requires
stockholder approval under applicable law. Notwithstanding the preceding
sentence, the Board shall in all events have the power to make such changes in
the Plan and the Committee shall in all events have the power to make such
changes in the regulations and administrative provisions under the Plan or in
any outstanding Option as, in the opinion of counsel for the Company, may be
necessary or appropriate from time to time to enable the Plan and any Option to
qualify as an employee stock purchase plan as defined in Section 423 of the
Code, so as to receive preferential federal income tax treatment. No amendment
shall adversely affect outstanding Options without the consent of the Optionee
and the termination of the Plan will not terminate Options then outstanding,
without the consent of the Optionee.

Notwithstanding the foregoing, at such time after the Company is not
required to file periodic reports under the Exchange Act, at its option, the
Company may terminate the Plan and upon the termination, outstanding Options
shall be cancelled and each Participant shall receive in cash an amount equal
to the accumulated payroll deductions credited to the Participant's account
under the Plan immediately prior to termination.

20. EFFECTIVE DATE AND DURATION OF THE PLAN

The Plan shall be effective as of April 1, 1998, subject only to
ratification by the holders of a majority of the outstanding shares of capital
stock present, or represented, and entitled to vote thereon (voting as a single
class) at a duly held meeting of the shareholders of the Company within twelve
months after such date. Unless the Plan shall have terminated earlier, the Plan
shall terminate on August 31, 2003 (or, if that date is not a business day, the
business day immediately preceding August 31, 2003), and no Option shall be
granted pursuant to the Plan after that date.

A-8

1477-PS-98

<PAGE>

DETACH HERE

PROXY

IRON MOUNTAIN INCORPORATED
745 ATLANTIC AVENUE
BOSTON, MASSACHUSETTS 02111

THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

The undersigned hereby appoints C. RICHARD REESE, DAVID S. WENDELL AND JOHN
F. KENNY, JR., and each of them, as proxies of the undersigned, each with the
power to appoint his substitute, and hereby authorizes a majority of them, or
any one if only one be present, to represent and to vote, as designated on the
reverse hereof, all the Common Stock, $.01 par value per share, of Iron Mountain
Incorporated held of record by the undersigned or with respect to which the
undersigned is entitled to vote or act at the Annual Meeting of Stockholders to
be held on May 28, 1998 at 9:30 a.m., local time, or any adjournment or
postponement thereof.

This proxy when properly executed will be voted in the manner directed
herein by the undersigned stockholder. If no direction is made, this proxy will
be voted FOR all of the Directors listed in Proposal 1 and FOR Proposals 2, 3, 4
and 5.

SEE REVERSE SEE REVERSE
SIDE CONTINUED AND TO BE SIGNED ON REVERSE SIDE SIDE

<PAGE>

IRON MOUNTAIN
America's Largest Records Management Company

April 23, 1998
Dear Stockholder:

It is a pleasure to invite you to the Company's 1998 Annual Meeting in
Boston, Massachusetts on Thursday, May 28, 1998, at 9:30 a.m., local time, at
the offices of Sullivan & Worcester LLP, 23rd Floor, One Post Office Square,
Boston, Massachusetts.

The Annual Report to Stockholders, Notice of Meeting, proxy statement and
form of proxy are included herein. The matters listed in the Notice of Meeting
are described in detail in the proxy statement.

The vote of every stockholder is important. Mailing your completed proxy
will not prevent you from voting in person at the meeting if you wish to do so.

Please sign, date and promptly mail your proxy. Your cooperation will be
greatly appreciated.

Your Board of Directors and management look forward to greeting those
stockholders who are able to attend.

Sincerely,

C. RICHARD REESE
Chairman of the Board and
Chief Executive Officer

DETACH HERE

[X] Please mark
votes as in
this example.

<TABLE>
<S> <C>
FOR AGAINST ABSTAIN
2. Proposal to approve the adoption of the [ ] [ ] [ ]
Iron Mountain Incorporated 1998 Employee
Stock Purchase Plan.
1. Election of the following Directors:
Nominees: Eugene B. Doggett, Constantin R. Boden and 3. Proposal to approve an amendment to the [ ] [ ] [ ]
Clarke H. Bailey Iron Mountain Incorporated 1995 Stock
Incentive Plan to increase the number of
FOR WITHHOLD shares of Common Stock authorized for
[ ] [ ] issuance thereunder from 1,400,000 to
2,000,000.

MARK HERE 4. Proposal to approve an amendment to the [ ] [ ] [ ]
FOR COMMENTS Iron Mountain Incorporated 1995 Stock
[ ] ______________________________________ OR ADDRESS [ ] Incentive Plan to increase the total
For all nominees except as noted above CHANGE AND number of shares of Common Stock with
NOTE BELOW respect to which options and Other Rights
may be granted thereunder to any single
employee from 250,000 to 350,000.

5. Ratification of the selection by the Board [ ] [ ] [ ]
of Directors of Arthur Andersen LLP as
independent public accountants for 1998.

6. In their discretion, the Proxies are authorized to vote upon such
other business as may properly come before the meeting.

Note: Please sign exactly as name appears hereon. Joint owners should
each sign. When signing as attorney, executor, administrator, trustee
or guardian, please give full title as such. If a corporation,
please sign in full corporate name by an authorized officer or if a
partnership, please sign in partnership name by an authorized person.

Signature: ______________________________ Date: __________________ Signature: _____________________________ Date: __________________

</TABLE>