LYONDELL PETROCHEMICAL CO
PREM14A, 1997-09-12
PETROLEUM REFINING
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________________________________________________________________________________

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
                           --------------------------
                                  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

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

[x]  Filed by the Registrant
 
[ ]  Filed by a Party other than the Registrant
 
Check the appropriate box:
 
[x]  Preliminary Proxy Statement
 
[ ]  Confidential, for Use of the Commission Only (as permitted by Rule
     14a-6(e)(2))
 
[ ]  Definitive Proxy Statement
 
[ ]  Definitive Additional Materials
 
[ ]  Soliciting Material Pursuant to Rule 14a-11(c) or Rule 14a-12
 
                                JOINT FILING BY:
 
                         LYONDELL PETROCHEMICAL COMPANY
                           MILLENNIUM CHEMICALS INC.
 
             (NAMES OF REGISTRANTS AS SPECIFIED IN THEIR CHARTERS)
 
Payment of Filing Fee (Check the appropriate box):
 
<TABLE>
<S>        <C>
[ ]        No fee required.
[x]        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:  Not applicable.
           2) Aggregate number of securities to which transaction applies:  Not applicable.
           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.):  $3.446 billion
              (representing the sum of pro forma partners' capital of $2.696 billion at closing and $750 million of cash
              to be received at closing by an affiliate of one of the partners).
           4) Proposed maximum aggregate value of transaction:  $3.446 billion.
           5) Total fee paid:  $689,200.00
[ ]        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: $.................................................................................
           2) Form, Schedule or Registration Statement no.:.............................................................
           3) Filing Party:.............................................................................................
           4) Date Filed:...............................................................................................
</TABLE>
 
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                        [LYONDELL]         [MILLENNIUM]
                            ------------------------
                           JOINT VENTURE PROPOSED --
                          YOUR VOTE IS VERY IMPORTANT
                            ------------------------
 
     LYONDELL PETROCHEMICAL COMPANY ('Lyondell') and MILLENNIUM CHEMICALS INC.
('Millennium') have agreed to combine most of our petrochemicals businesses to
form a joint venture that we expect will be the largest producer of ethylene and
polyethylene in North America. The joint venture, to be organized as a
partnership, will be named                         and will be headquartered in
Houston, Texas.
 
     Lyondell will contribute to the joint venture substantially all of the
assets comprising its petrochemicals and polymers business segments, as well as
a $345 million note, in exchange for a 57% interest in the joint venture and the
joint venture's assumption of certain liabilities. Millennium will contribute to
the joint venture substantially all of the assets comprising its polyethylene
and related products, performance polymers and ethyl alcohol businesses in
exchange for a 43% interest in the joint venture, $750 million in repayment of
debt due to it from its contributed businesses, $250 million upon collection of
certain retained accounts receivable and the joint venture's assumption of
certain liabilities. At the closing, a subsidiary of Millennium will guarantee
$750 million of the joint venture's debt.
 
     Lyondell and Millennium believe the joint venture represents a logical
extension of both companies' strategic plans to enhance stockholder value. It
will provide opportunities for significant costs savings and expanded business
opportunities that should lead to improved earnings and cash flow from the
contributed businesses and, therefore, improved stockholder returns for both
companies.
 
     Your company's Board of Directors has unanimously determined that the joint
venture is in the best interests of your company and unanimously recommends that
you vote 'FOR' it.
 
     The joint venture will not go into effect unless the stockholders of both
companies approve it. Each of us has scheduled a special meeting for our
stockholders to vote on the joint venture. YOUR VOTE IS VERY IMPORTANT.
 
     Whether or not you plan to attend your company's meeting, please take the
time to vote by completing and mailing the enclosed proxy card to us. If you
sign, date and mail your proxy card without indicating how you want to vote,
your proxy will be counted as a vote in favor of the joint venture. If you fail
to return your card, the effect will be the same as a vote against the joint
venture.
 
     The dates, times and places of the meetings are as follows:
 
<TABLE>
<S>                                                            <C>
FOR LYONDELL STOCKHOLDERS:                                     FOR MILLENNIUM STOCKHOLDERS:
[Date]                                                         [Date]
[Time]                                                         [Time]
[Place]                                                        [Place]
</TABLE>
 
     This letter constitutes the formal notice of your company's meeting and is
being sent to you by order of your company's Board of Directors. The Joint Proxy
Statement following this letter provides you with detailed information about the
proposed joint venture. In addition, you may obtain information about our
companies from documents that we have filed with the Securities and Exchange
Commission. We encourage you to read all of this information carefully.
 
<TABLE>
<S>                                                           <C>
Dan F. Smith                                                  William M. Landuyt
President and Chief Executive Officer                         Chairman of the Board and Chief Executive Officer
LYONDELL PETROCHEMICAL COMPANY                                MILLENNIUM CHEMICALS INC.
</TABLE>
 
           Joint Proxy Statement dated                   , 1997, and
            first mailed to stockholders on                   , 1997
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                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                              ----
<S>                                                                                                           <C>
QUESTIONS AND ANSWERS ABOUT THE JOINT VENTURE..............................................................      1
SUMMARY....................................................................................................      5
JOINT VENTURE STRUCTURE....................................................................................     11
THE SPECIAL MEETINGS.......................................................................................     12
     General...............................................................................................     12
     Matters to Be Considered at the Special Meetings......................................................     12
     Record Date; Quorum; Voting at the Meetings...........................................................     13
     Proxies...............................................................................................     14
THE PROPOSED JOINT VENTURE.................................................................................     16
     Background............................................................................................     16
     Reasons for the Joint Venture Transaction.............................................................     18
     Recommendation of the Lyondell Board of Directors.....................................................     20
     Recommendation of the Millennium Board of Directors...................................................     20
     Opinion of Financial Advisor to Lyondell..............................................................     20
     Opinion of Financial Advisor to Millennium............................................................     23
     Certain Consequences of the Joint Venture Transaction.................................................     26
     Interest of Certain Persons in the Joint Venture Transaction..........................................     27
     Accounting Treatment..................................................................................     28
     Federal Income Tax Consequences of the Joint Venture Transaction......................................     28
     No Appraisal Rights...................................................................................     28
     Closing Date..........................................................................................     28
THE PARTIES................................................................................................     28
     Lyondell..............................................................................................     28
     Millennium............................................................................................     29
SELECTED HISTORICAL AND UNAUDITED PRO FORMA FINANCIAL DATA OF LYONDELL, MILLENNIUM AND THE PARTNERSHIP.....     30
     Introduction..........................................................................................     30
     Selected Historical and Unaudited Pro Forma Financial Data of Lyondell................................     31
     Selected Historical and Unaudited Pro Forma Financial Data of Millennium..............................     36
     Unaudited Pro Forma Financial Data of the Partnership.................................................     41
BUSINESSES TO BE CONTRIBUTED TO THE PARTNERSHIP............................................................     43
     Lyondell..............................................................................................     43
     Millennium............................................................................................     46
     Manufacturing Operations of the Partnership...........................................................     50
FINANCING ARRANGEMENTS FOR THE PARTNERSHIP.................................................................     51
     The New Credit Facility...............................................................................     51
     Lyondell Note.........................................................................................     51
     Millennium Contributed Debt...........................................................................     52
     Assumed Lyondell Debt.................................................................................     52
     Liquidity and Capital Resources.......................................................................     52
THE MASTER TRANSACTION AGREEMENT...........................................................................     53
     General...............................................................................................     53
     Closing Date..........................................................................................     53
     Certain Covenants and Agreements......................................................................     53
     Conditions to Closing.................................................................................     56
     Termination...........................................................................................     57
     Expenses..............................................................................................     60
     Amendment and Waiver..................................................................................     60
THE ASSET CONTRIBUTION AGREEMENTS..........................................................................     60
     Contributed Assets....................................................................................     60
     Excluded Assets.......................................................................................     61
     Assumed Liabilities...................................................................................     61
</TABLE>
 
                                       i
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<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                              ----
<S>                                                                                                           <C>
     Excluded Liabilities..................................................................................     62
     Covenants Subsequent to Closing Date..................................................................     62
     Indemnification.......................................................................................     63
     Payment of Certain Expenses and Taxes.................................................................     65
THE PARTNERSHIP AGREEMENT..................................................................................     65
     General...............................................................................................     65
     Governance............................................................................................     65
     Unanimous Voting Requirements.........................................................................     66
     Transactions with Affiliates..........................................................................     67
     Officers..............................................................................................     68
     Strategic Plans and Annual Budgets; Expenses..........................................................     68
     Distribution of Available Net Operating Cash..........................................................     70
     Capital Contributions.................................................................................     70
     Description of Partners...............................................................................     71
     Indemnification.......................................................................................     71
     Partners' Right of Contribution.......................................................................     71
     Transfers and Pledges.................................................................................     71
     Default...............................................................................................     73
     Dissolution and Termination...........................................................................     74
     Limitation of Fiduciary Duties; Non-Competition.......................................................     75
     Financial and Accounting Matters; Audits..............................................................     76
     Financial and Other Information.......................................................................     76
THE PARENT AGREEMENT.......................................................................................     77
     Guarantee of Obligations..............................................................................     77
     Restrictions on Transfer and Pledge of Partner Sub Stock..............................................     77
     Right of First Option.................................................................................     78
     Standstill Agreement..................................................................................     78
     Competing Business....................................................................................     79
CERTAIN RELATED PARTY TRANSACTIONS.........................................................................     79
MARKET PRICE INFORMATION...................................................................................     80
MANAGEMENT OF THE PARTNERSHIP..............................................................................     80
     Executive Officers....................................................................................     80
     Experience of Executive Officers......................................................................     80
     Executive Agreements..................................................................................     82
OWNERSHIP OF LYONDELL COMMON STOCK BY CERTAIN BENEFICIAL OWNERS AND MANAGEMENT.............................     82
     Certain Beneficial Owners.............................................................................     82
     Directors and Executive Officers......................................................................     83
OWNERSHIP OF MILLENNIUM COMMON STOCK BY CERTAIN BENEFICIAL OWNERS AND MANAGEMENT...........................     84
     Certain Beneficial Owners.............................................................................     84
     Directors and Executive Officers......................................................................     84
FUTURE STOCKHOLDER PROPOSALS...............................................................................     85
WHERE YOU CAN FIND MORE INFORMATION........................................................................     86
OTHER MATTERS..............................................................................................     87
INDEX TO FINANCIAL STATEMENTS..............................................................................    F-1
 
ANNEX A Fairness Opinion of Salomon Brothers Inc...........................................................    A-1
ANNEX B Fairness Opinion of J.P. Morgan Securities Inc.....................................................    B-1
</TABLE>
 
                                       ii
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                FORWARD-LOOKING STATEMENTS MAY PROVE INACCURATE
 
     We have each made forward-looking statements in this document (and in
documents that are incorporated by reference) that are subject to risks and
uncertainties. Forward-looking statements include information concerning the
possible or assumed future results of operations of the businesses to be
contributed by Lyondell and Millennium and the partnership. Also, when we use
words such as 'believe,' 'expect,' 'anticipate' or similar expressions, we are
making forward-looking statements. Stockholders should note that many factors,
some of which are discussed elsewhere in this document and in the documents
which we incorporate by reference, could affect the future financial results of
Lyondell, Millennium and the partnership and could cause their actual future
results to differ materially from those anticipated in our forward-looking
statements. These factors include the following:
 
      -  the balance between industry production capacity and operating rates,
         on the one hand, and demand for our products, such as ethylene and
         polyethylene, on the other hand;
 
      -  the economic trends in the United States and other countries which are
         marketplaces for our products;
 
      -  customer inventory levels;
 
      -  competitive pricing pressures;
 
      -  the cost and availability of feedstocks and other raw materials, such
         as petroleum liquids, natural gas, natural gas liquids and ethylene;
 
      -  operating interruptions (including leaks, explosions, fires, mechanical
         failures, unscheduled downtime, transportation interruptions, spills,
         releases and other environmental risks);
 
      -  competitive technology positions;
 
      -  delays in achieving productivity improvements and cost-reduction
         targets or completing construction projects on schedule;
 
      -  difficulties that may be encountered in combining the two businesses,
         in achieving synergies as anticipated or in managing the businesses as
         a partnership; and
 
      -  the risk that our analyses of these risks and forces could be incorrect
         and/or that the strategies developed to address them could be
         unsuccessful.
 
                                      iii
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                 QUESTIONS AND ANSWERS ABOUT THE JOINT VENTURE
 
Q: WHAT IS '                        , L.P.'?
 
A:                         , L.P. is the name that Lyondell and Millennium have
   agreed to use for the joint venture partnership that will operate their
   contributed businesses. In this Joint Proxy Statement, we have referred to
                           , L.P. as the 'Partnership.' The Partnership
   Agreement is described in detail on pages 65 through 76.
 
Q: WHY ARE LYONDELL AND MILLENNIUM PROPOSING TO CREATE THE PARTNERSHIP? HOW WILL
   I BENEFIT?
 
A: Our companies are proposing to combine most of our petrochemicals businesses
   in the Partnership because we believe the Partnership represents a logical
   extension of both companies' strategic plans to enhance stockholder value.
   The Partnership will provide opportunities for significant cost savings and
   expanded business opportunities that should lead to improved earnings and
   cash flow from the contributed businesses and, therefore, improved
   stockholder returns for both companies. In this Joint Proxy Statement, we
   have referred to the transactions involved in combining these businesses as
   the 'Joint Venture Transaction.' We expect that, at the time we contribute
   our petrochemicals businesses to the Partnership, it will be the largest
   producer of ethylene and polyethylene in North America. We believe that, over
   time, the Partnership will provide a significantly better return on the
   assets of our two contributed businesses than either of us could achieve by
   operating the businesses separately. We expect that this added value will
   benefit all of the stockholders of each of our companies. To review the
   background and reasons for the Joint Venture Transaction in greater detail,
   see pages 16 through 19.
 
Q: WHAT ARE LYONDELL GP AND MILLENNIUM GP?
 
A: Lyondell GP and Millennium GP are the general partners of the Partnership. As
   general partners, they will be responsible for operating the Partnership and
   will have unlimited liability for the debts and other liabilities of the
   Partnership. In this Joint Proxy Statement, we have referred to Lyondell GP
   and Millennium GP as the 'General Partners.' Lyondell GP is a direct
   wholly-owned subsidiary of Lyondell, and Millennium GP is an indirect
   wholly-owned subsidiary of Millennium.
 
Q: HOW WILL THE PARTNERSHIP BE MANAGED?
 
A: The day-to-day operations of the Partnership will be managed by its executive
   officers under the supervision of a Partnership Governance Committee that
   will act much like a board of directors of a corporation. The Partnership
   Governance Committee will have six members, two of whom will serve as
   co-chairs. Lyondell and Millennium, through Lyondell GP and Millennium GP,
   will each appoint three committee members, including one co-chair.
 
         Lyondell and Millennium will have an equal voice in the most important
    joint venture decisions. Among other things, both Lyondell and Millennium
    must agree on:
 
    - changes in the basic scope of the Partnership's business
 
    - the annually updated five-year Strategic Plans that will define the
      business goals and strategy of the Partnership
 
    - sales or purchases of assets or capital expenditures of more than $30
      million that are not contemplated by the then-current Strategic Plan
 
    - requiring additional investments in the Partnership not contemplated in an
      approved Strategic Plan, if the partners are asked to invest more than a
      total of $100 million in a single year or more than a total of $300
      million in a five-year period (except in specific circumstances that have
      been described in the Partnership Agreement)
 
    - borrowing money under certain circumstances
 
    - issuing or repurchasing equity securities of the Partnership
 
    - hiring and firing executive officers other than the CEO
 
    - approving material compensation and benefit plans for employees
 
    - commencing or settling important lawsuits
 
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    - changing accountants or accounting methods
 
    - merging or combining with another business.
 
         All decisions of the Partnership Governance Committee that do not
    require unanimity between Lyondell and Millennium may be made by Lyondell's
    representatives alone. Among other matters, these decisions include:
 
   - approval of the Partnership's Annual Budget (which must be consistent with
     the information for the relevant year included in the most recent
     unanimously approved Strategic Plan)
 
   - selection of the Partnership's CEO (who must be reasonably acceptable to
     Millennium).
 
Q: WHAT ARE LYONDELL LP AND MILLENNIUM LP?
 
A: Lyondell LP and Millennium LP are the limited partners of the Partnership. As
   limited partners, Lyondell LP and Millennium LP will not take part in
   managing the Partnership. In this Joint Proxy Statement, we have referred to
   Lyondell LP and Millennium LP as the 'Limited Partners.'
 
Q: WHAT PARTS OF LYONDELL AND MILLENNIUM WILL BE TRANSFERRED TO THE PARTNERSHIP?
 
A: Lyondell will transfer its petrochemicals and polymers business segments to
   the Partnership, except for some assets that it and Millennium have agreed
   will stay with Lyondell. Lyondell will also give the Partnership a $345
   million promissory note payable by Lyondell to the Partnership.
 
        Millennium will contribute its polyethylene and related products
   business, its performance polymers business and its ethyl alcohol business,
   except for some assets that it and Lyondell have agreed will stay with
   Millennium.
 
Q: WHAT BUSINESSES WILL LYONDELL AND MILLENNIUM KEEP AND NOT CONTRIBUTE TO THE
   PARTNERSHIP?
 
A: Lyondell will not contribute to the Partnership its interests in its methanol
   business, Lyondell Methanol Company, L.P., or its interest in its refining
   business, LYONDELL-CITGO Refining Company Ltd.
 
        Millennium will not contribute to the Partnership certain assets of its
   petrochemicals business, including those used to produce vinyl acetate
   monomer, acetic acid, synthesis gas and methanol, and the petrochemicals
   headquarters facility located in Cincinnati, Ohio. In addition, Millennium
   will not contribute any assets of Millennium Inorganic Chemicals (its
   titanium dioxide, titanium tetrachloride, cadmium/selenium pigments and
   silica gel businesses) or of Millennium Specialty Chemicals (its fragrances
   and flavors business), or its equity interest in Suburban Propane Partners,
   L.P. Millennium will also keep $250 million from the accounts receivable that
   relate to petrochemicals products sold before the completion of the Joint
   Venture Transaction.
 
Q: WHAT DO LYONDELL AND MILLENNIUM GET FOR CONTRIBUTING BUSINESSES TO THE
   PARTNERSHIP?
 
A: Lyondell will receive a 57% interest in the Partnership in the form of
   general and limited partner units. In addition, the Partnership will assume
   primary liability for $745 million of Lyondell's indebtedness (although
   Lyondell will also remain liable for this debt until its maturity).
 
        Millennium will receive a 43% interest in the Partnership in the form of
   general and limited partner units. In addition, the Partnership will pay $750
   million in cash to Millennium to pay off indebtedness due it from its
   contributed businesses that the Partnership will assume. The Partnership will
   obtain this cash from its new bank credit facility. A subsidiary of
   Millennium will guarantee $750 million of the amount borrowed under this
   facility. Millennium intends to use the $750 million received in cash, plus
   the $250 million from the collection of its retained accounts receivable, to
   reduce its bank debt.
 
Q: WHY IS LYONDELL RECEIVING 57% OF THE PARTNERSHIP WHILE MILLENNIUM RECEIVES
   43%?
 
A: The values of the businesses that each of us will contribute to the
   Partnership have been carefully evaluated by each of us and our independent
   financial advisors. Our ownership interests in the Partnership were
 
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   adjusted to reflect Lyondell's contributed debt and $345 million note
   payable, as well as the $750 million in cash that Millennium will receive and
   Millennium's collection of $250 million from accounts receivable relating to
   products sold before the closing of the Joint Venture Transaction. We believe
   that both companies are receiving a fair share of the Partnership in exchange
   for what they are contributing. In fact, each company has received an opinion
   from an independent financial advisor that the Joint Venture Transaction is
   fair to it from a financial point of view. These opinions are attached as
   Annexes A and B to this Joint Proxy Statement.
 
Q: WHEN DO YOU EXPECT TO COMPLETE THE JOINT VENTURE TRANSACTION?
 
A: We are working toward completing the Joint Venture Transaction as quickly as
   possible. In addition to stockholder approvals, we must also satisfy some
   other conditions. We hope to complete the Joint Venture Transaction on or
   before January 1, 1998.
 
Q: WILL LYONDELL AND MILLENNIUM BE REQUIRED TO FUND THE PARTNERSHIP IN THE
   FUTURE?
 
A: We believe that the Partnership normally will be able to generate enough
   funds to pay for its expenses and finance its growth and also pay regular
   distributions to the partners. However, if the Partnership is not able to
   generate sufficient funds or needs funds in addition to those available from
   its credit facilities or agreed to in a Strategic Plan that will be approved
   by both of us, the Partnership Governance Committee (acting, for these
   purposes, through its Lyondell-selected representatives) can require Lyondell
   and Millennium to invest up to a total of $100 million per year in the
   Partnership (but not more than a total of $300 million in any five
   consecutive years). For example, if an additional $100 million were required
   in a particular year, Lyondell would invest an additional $57 million and
   Millennium would invest an additional $43 million. Except in specific
   circumstances that have been described in the Partnership Agreement, both
   Lyondell and Millennium must agree on any capital contributions of a total of
   more than $100 million in any year (or more than a total of $300 million in
   any five consecutive years).
 
Q: WHO ARE THE EXECUTIVES THAT WILL OPERATE THE PARTNERSHIP?
 
A: We have assembled an experienced team of executives to manage the
   Partnership. All of these executives currently work for Lyondell or
   Millennium. Dan F. Smith will be the Chief Executive Officer of the
   Partnership and also will remain as the President and Chief Executive Officer
   of Lyondell. Eugene R. Allspach, Millennium Petrochemicals' Group Vice
   President, Manufacturing and Technology, will become the President and Chief
   Operating Officer of the Partnership. Other executives are listed under
   'Management of the Partnership' (page 80).
 
Q: WHAT HAPPENS IF LYONDELL AND MILLENNIUM CANNOT AGREE ON HOW TO OPERATE THE
   PARTNERSHIP?
 
A: For the most important decisions, as we have described above, the Partnership
   Agreement requires the approval of two Partnership Governance Committee
   representatives appointed by Lyondell GP and two representatives appointed by
   Millennium GP, so these decisions cannot be made unless both Lyondell and
   Millennium agree. The Partnership Agreement provides a process through which
   Lyondell and Millennium can try to work out any differences they may have on
   these matters. If Lyondell and Millennium cannot agree on an updated
   Strategic Plan for two years, either company may initiate a procedure to
   dissolve the Partnership and divide its assets.
 
Q: WHAT ARE THE TAX CONSEQUENCES TO ME OF THE JOINT VENTURE TRANSACTION?
 
A: The Joint Venture Transaction will have no federal income tax consequences
   for the stockholders of either company.
 
Q: WHAT VOTE IS REQUIRED IN ORDER TO APPROVE THE JOINT VENTURE TRANSACTION?
 
A: At each company's special meeting, we must receive votes 'FOR' the Joint
   Venture Transaction from holders of a majority of the shares of its common
   stock that are outstanding.
 
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Q: IF MY SHARES ARE HELD IN 'STREET NAME' BY MY BROKER, WILL MY BROKER VOTE MY
   SHARES FOR ME?
 
A: Your broker will vote your shares only if you provide instructions on how to
   vote. You should instruct your broker to vote your shares, following the
   directions provided by your broker. Without instructions, your shares will
   not be voted.
 
Q: SHOULD I SEND IN MY STOCK CERTIFICATES?
 
A: No. Your stock certificates will not be affected by this transaction. You
   will continue to hold shares in your company and, if the Joint Venture
   Transaction is completed, subsidiaries of your company will own interests in
   the Partnership.
 
Q: WHEN WILL THE SPECIAL MEETINGS OCCUR?
 
A: The Lyondell special meeting and the Millennium special meeting will each
   take place at   :00 a.m. on            , 1997. Directions to the special
   meeting locations are shown on the inside back cover of this Joint Proxy
   Statement. You may attend your company's special meeting and vote your shares
   in person, rather than signing and mailing your proxy card. In addition, you
   may take back your proxy up to and including the day of your company's
   special meeting by following the directions on pages 14 and 15 and change
   your vote by either signing a new proxy or attending your company's special
   meeting and voting in person.
 
Q: WHAT DO I NEED TO DO NOW?
 
A: Just indicate on your proxy card how you want to vote, and sign and mail it
   in the enclosed return envelope as soon as possible, so that your shares may
   be represented at your company's special stockholders meeting. If you sign
   and send in your proxy and do not indicate how you want to vote, your proxy
   will be counted as a vote in favor of the Joint Venture Transaction. If you
   do not vote or you abstain, it will have the effect of a vote against your
   company's contribution of assets to the Partnership.
 
   YOUR BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR THE JOINT
  VENTURE TRANSACTION, INCLUDING YOUR COMPANY'S CONTRIBUTION OF ASSETS TO THE
                                  PARTNERSHIP.
 
                       WHO CAN HELP ANSWER YOUR QUESTIONS
 
   If you have more questions about the Joint Venture Transaction you should
                                    contact:
 
<TABLE>
<S>                                                 <C>
              LYONDELL STOCKHOLDERS:                             MILLENNIUM STOCKHOLDERS:
          Lyondell Petrochemical Company                        Millennium Chemicals Inc.
         1221 McKinney Street, Suite 1600                          99 Wood Avenue South
               Houston, Texas 77010                                   P.O. Box 7050
            Attention: Kevin DeNicola                            Iselin, New Jersey 08830
           Phone Number: (713) 652-4590                          Attention: Mickey Foster
                                                               Phone Number: (732) 603-6868
</TABLE>
 
       If you would like additional copies of the Joint Proxy Statement,
  or if you have questions about how to vote your shares, you should contact:
 
                            Georgeson & Company Inc.
                               Wall Street Plaza
                            New York, New York 10005
 
                   Phone Number (U.S. & Canada): 800-223-2064
                    (Outside U.S. and Canada): 212-440-9800
 
                                       4
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                                    SUMMARY
 
     This summary highlights selected information from this document and does
not contain all of the information that is important to you. To understand the
Joint Venture Transaction fully and for a more complete description of the legal
terms of the Joint Venture Transaction, you should read carefully this entire
document and the documents to which we have referred you. See 'Where You Can
Find More Information' (page 86). We have included page references
parenthetically to direct you to a more complete description of the topics
presented in this Summary.
 
THE PARTIES (PAGE 28)
LYONDELL PETROCHEMICAL COMPANY
1221 MCKINNEY STREET, SUITE 1600
HOUSTON, TEXAS 77010
PHONE NUMBER: (713) 652-7200
 
     Lyondell is a leading low-cost petrochemicals and polymers producer.
Lyondell manufactures a wide variety of petrochemicals, including ethylene,
propylene, butadiene, aromatics and specialty products, and polymers, including
high density polyethylene ('HDPE'), low-density polyethylene ('LDPE') and
polypropylene. Lyondell's petrochemicals and polymers products are used
primarily in the manufacture of other chemicals and products, which in turn are
used in the production of a wide variety of consumer and industrial products.
Lyondell produces methanol through its interest in Lyondell Methanol Company,
L.P., and produces refined petroleum products (including gasoline, low sulfur
diesel, jet fuel, aromatics and lubricants, or 'lube oils') through its interest
in LYONDELL-CITGO Refining Company Ltd., a venture jointly owned with CITGO
Petroleum Corporation.
 
MILLENNIUM CHEMICALS INC.
99 WOOD AVENUE SOUTH
P.O. BOX 7050
ISELIN, NEW JERSEY 08830
PHONE NUMBER: (732) 603-6600
LAPORTE ROAD
STALLINGBOROUGH
NR. GRIMSBY, NORTH EAST LINCOLNSHIRE
DN40 2PR ENGLAND
PHONE NUMBER: 0345 662663
 
     Millennium is a major international chemicals company, with leading market
positions in a broad range of commodity, industrial, performance and specialty
chemicals. Through its subsidiaries, Millennium is the largest producer of
polyethylene products in the United States; the second largest producer of
titanium dioxide ('TiO2') in the United States and the third largest producer of
TiO2 in the world; the second largest producer of acetic acid and vinyl acetate
monomer ('VAM') in the United States; a leading producer of high value-added
performance polymers, and of titanium tetrachloride ('TiCl4'), cadmium/selenium
pigments and silica gel; and a leading producer of fragrances and flavors
chemicals derived from crude sulfate turpentine. Millennium also owns a 26.4%
interest in Suburban Propane Partners, L.P. ('Suburban Propane'), a partnership
which is the third-largest retail marketer of propane in the United States.
 
THE JOINT VENTURE TRANSACTION
 
     The Joint Venture Transaction is described in detail in the Master
Transaction Agreement, dated July 25, 1997, between Lyondell and Millennium (the
'Master Transaction Agreement'). The Master Transaction Agreement is a 'roadmap'
that describes each party's rights and responsibilities in connection with the
Joint Venture Transaction.
 
THE PARTNERSHIP AND THE ASSET CONTRIBUTIONS
 
     Under separate Asset Contribution Agreements (the 'Asset Contribution
Agreements'), Lyondell and Millennium will contribute certain businesses to the
Partnership, a newly-formed Delaware limited partnership. Lyondell will
contribute to the Partnership substantially all of the assets comprising
Lyondell's petrochemicals and polymers businesses, as well as a $345 million
Lyondell promissory note payable to the Partnership. Millennium will contribute
to the Partnership substantially all of the assets comprising Millennium's
polyethylene and related products, performance polymers and ethyl alcohol
businesses other than accounts receivable relating to products sold before the
closing. All of the Partnership's businesses will be petrochemicals businesses
of one type or another.
 
     In exchange for the businesses transferred to the Partnership under the
Asset Contribution
 
                                       5
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Agreements, Lyondell GP and Lyondell LP will receive 57% of the Partnership's
units and Millennium GP and Millennium LP will receive 43% of the Partnership's
units. The Partnership will assume from Lyondell and Millennium responsibility
for certain liabilities related to their contributed petrochemicals businesses.
See 'The Asset Contribution Agreements -- Assumed Liabilities.' In addition, the
Partnership will pay $750 million in cash to Millennium to pay off indebtedness
due it from the Millennium contributed businesses that the Partnership will
assume. A subsidiary of Millennium will then guarantee $750 million of the
Partnership's debt. The Partnership will assume primary liability for $745
million of Lyondell's indebtedness (although Lyondell will also continue to be
liable for such debt until its maturity).
 
     Lyondell has formed Lyondell GP and Millennium has formed Millennium GP to
serve as the two general partners of the Partnership. In addition, Lyondell has
formed Lyondell LP and Millennium has formed Millennium LP to serve as the two
limited partners of the Partnership. Lyondell GP, Millennium GP, Lyondell LP and
Millennium LP have entered into a Limited Partnership Agreement (the
'Partnership Agreement') that governs the operation of the Partnership.
 
GOVERNANCE
 
     The Partnership's day-to-day operations will be managed by its executive
officers under the supervision of its governing body, the Partnership Governance
Committee. The Partnership Governance Committee will act much like a board of
directors of a corporation. The Partnership Governance Committee will have six
members, two of whom will serve as co-chairs. Through Lyondell GP and Millennium
GP, Lyondell and Millennium will each appoint three members, including one
co-chair. Lyondell and Millennium will have an equal voice in the most important
joint venture decisions. Among other things, both Lyondell and Millennium must
agree on:
 
- - changes in the basic scope of the Partnership's business
 
- - the annually updated five-year Strategic Plans that will define the business
  goals and strategy of the Partnership
 
- - sales or purchases of assets or capital expenditures of more than $30 million
  that are not contemplated by the then-current Strategic Plan
 
- - requiring additional investments in the Partnership not contemplated in an
  approved Strategic Plan, if the partners are asked to invest more than a total
  of $100 million in a single year or more than a total of $300 million in a
  five-year period (except in specific circumstances that have been described in
  the Partnership Agreement)
 
- - borrowing money under certain circumstances
 
- - issuing or repurchasing equity securities of the Partnership
 
- - hiring and firing executive officers other than the CEO
 
- - approving material compensation and benefit plans for employees
 
- - commencing or settling important lawsuits
 
- - changing accountants or accounting methods
 
- - merging or combining with another business.
 
     All decisions of the Partnership Goverance Committee that do not require
unanimity between Lyondell and Millennium may be made by Lyondell's
representatives alone. Among other matters, these decisions include:
 
- - approval of the Partnership's Annual Budget (which must be consistent with the
  information for the relevant year included in the most recent unanimously
  approved Strategic Plan)
 
- - selection of the Partnership's CEO (who must be reasonably acceptable to
  Millennium).
 
CONSEQUENCES TO LYONDELL AND MILLENNIUM
 
     After the closing (the 'Closing') of Lyondell's and Millennium's asset
contributions to the Partnership and the other transactions contemplated by the
Master Transaction Agreement, Lyondell and Millennium will continue to exist and
their certificates of incorporation and by-laws will remain unchanged. However,
immediately following the Joint Venture Transaction, most of Lyondell's
petrochemicals and polymers business segments and most of Millennium's
petrochemicals business will be owned by the Partnership, and Lyondell and
Millennium will participate in those businesses only through their
 
                                       6
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<PAGE>
interests in the Partnership. Immediately following the Closing, Lyondell will
retain its interests in its refining and methanol businesses, although the
Partnership will provide operating and other services for Lyondell Methanol
Company, L.P. and will provide marketing and other services for LYONDELL-CITGO
Refining Company Ltd. Similarly, Millennium will continue to operate its VAM,
acetic acid, synthesis gas, methanol, TiO2, TiCl4, cadmium/selenium pigments,
silica gel and fragrances and flavors businesses, and will also retain its
interest in Suburban Propane.
 
     The Partnership will distribute to its partners all Available Net Operating
Cash monthly in accordance with their respective ownership interests. Lyondell
will receive 57% of all distributions, and Millennium will receive the remaining
43%. See 'The Partnership Agreement -- Distribution of Available Net Operating
Cash.'
 
     After the formation of the Partnership, Lyondell and Millennium and their
subsidiaries will continue to have various obligations to the Partnership and to
each other. At the Closing, Lyondell and Millennium will enter into a Parent
Agreement under which Lyondell and Millennium -- the parent corporations in
which you own stock -- will guarantee the performance by their subsidiaries of
all such obligations under the Partnership Agreement and various other
agreements.
 
REASONS FOR THE JOINT VENTURE TRANSACTION (PAGE 18)
 
     Lyondell and Millennium believe the Partnership represents a logical
extension of both companies' strategic plans to enhance stockholder value. It
will provide opportunities for significant cost savings and expanded business
opportunities that should lead to improved earnings and cash flow from the
contributed businesses and, therefore, improved stockholder returns for both
companies. The goal of the Partnership will be to maximize long-term cash flow
and economic value creation through the safe and efficient operation of its
business and assets. As a result of the Joint Venture Transaction, Lyondell and
Millennium expect that, over time, the Partnership will achieve significant cost
benefits and savings compared to the combined cost to Lyondell and Millennium of
operating the two businesses separately.
 
     To review the background and reasons for the Joint Venture Transaction in
greater detail see pages 16 through 19.
 
RECOMMENDATIONS TO STOCKHOLDERS (PAGE 20)
 
To the Lyondell Stockholders:
 
     THE LYONDELL BOARD BELIEVES THAT THE JOINT VENTURE TRANSACTION IS FAIR TO
LYONDELL AND IN ITS BEST INTEREST AND UNANIMOUSLY RECOMMENDS THAT YOU VOTE 'FOR'
THE JOINT VENTURE TRANSACTION.
 
To the Millennium Stockholders:
 
     THE MILLENNIUM BOARD BELIEVES THAT THE JOINT VENTURE TRANSACTION IS FAIR TO
MILLENNIUM AND IN ITS BEST INTEREST AND UNANIMOUSLY RECOMMENDS THAT YOU VOTE
'FOR' THE JOINT VENTURE TRANSACTION.
 
FAIRNESS OPINIONS OF FINANCIAL ADVISORS (PAGE 20)
 
     In deciding to approve the Joint Venture Transaction, each Board considered
the opinion of its financial advisor as to the fairness of the Joint Venture
Transaction to it from a financial point of view. Lyondell received an opinion
from its financial advisor, Salomon Brothers Inc, and Millennium received an
opinion from its financial advisor, J.P. Morgan Securities Inc. These opinions
are attached as Annexes A and B to this Joint Proxy Statement. WE ENCOURAGE YOU
TO READ THESE OPINIONS CAREFULLY.
 
THE STOCKHOLDERS' MEETINGS (PAGE 12)
 
     The Lyondell Meeting will be held at                   , at   :00 A.M. on
           , 1997. At the special meeting, Lyondell stockholders will be asked
to approve the Joint Venture Transaction.
 
     The Millennium Meeting will be held at                   , at   :00 A.M. on
           , 1997. At the special meeting, Millennium stockholders will be asked
to approve the Joint Venture Transaction.
 
RECORD DATE; VOTING POWER (PAGE 13)
 
     You are entitled to vote at your company's special meeting if you owned
shares as of the close of the relevant record date. The Lyondell Record Date and
the Millennium Record Date have been fixed for            , 1997 and
           , 1997, respectively.
 
                                       7
 <PAGE>
<PAGE>
     On the Lyondell Record Date, there were 80,000,000 shares of Lyondell
Common Stock outstanding and allowed to vote at the Lyondell Meeting. Lyondell
stockholders will have one vote at the special meeting for each share of
Lyondell Common Stock held of record on the Lyondell Record Date.
 
     On the Millennium Record Date, there were 77,089,378 shares of Millennium
Common Stock outstanding and allowed to vote at the Millennium Meeting.
Millennium stockholders will have one vote at the special meeting for each share
of Millennium Common Stock held of record on the Millennium Record Date.
 
VOTES REQUIRED (PAGE 13)
 
     Holders of a majority of the shares of Lyondell Common Stock outstanding on
the Lyondell Record Date must vote in favor of the Joint Venture Transaction in
order to approve it. Holders of a majority of the shares of Millennium Common
Stock outstanding on the Millennium Record Date must vote in favor of the Joint
Venture Transaction in order to approve it.
 
SHARE OWNERSHIP OF MANAGEMENT AND CERTAIN STOCKHOLDERS (PAGES 82-85)
 
     On the Lyondell Record Date, directors and executive officers of Lyondell
and their affiliates beneficially owned 480,312 shares of Lyondell Common Stock,
or less than 1% of the shares of Lyondell Common Stock outstanding on the
Lyondell Record Date.
 
     On the Millennium Record Date, directors and executive officers of
Millennium and their affiliates beneficially owned 2,023,809 shares of
Millennium Common Stock, or approximately 2.6% of the shares of Millennium
Common Stock outstanding on the Millennium Record Date.
 
     Each of the directors and executive officers of each company has indicated
that he or she intends to vote his or her Lyondell Common Stock or Millennium
Common Stock 'for' approval of the Joint Venture Transaction.
 
THE TRANSACTION DOCUMENTS (PAGES 53-79)
 
     The Master Transaction Agreement, Asset Contribution Agreements,
Partnership Agreement and Parent Agreement have been filed with the Securities
and Exchange Commission (the 'SEC'), are incorporated by reference herein and
are publicly available. We encourage you to read each of these documents, which
are the primary legal documents governing the Joint Venture Transaction. See
'Where You Can Find More Information.'
 
CONDITIONS TO THE JOINT VENTURE TRANSACTION (PAGE 56)
 
     We will complete the Joint Venture Transaction only if we satisfy or (in
some cases) waive several conditions that we agreed to in the Master Transaction
Agreement, including the following:
 
- - holders of a majority of the common stock of both Lyondell and Millennium
  approve the Joint Venture Transaction
 
- - no legal restraints or prohibitions exist which prevent the completion of the
  Joint Venture Transaction, limit the conduct of the businesses of the
  Partnership or limit the ownership by the Partnership of the contributed
  businesses
 
- - holders of certain long term debt issued by Millennium America Inc., a
  subsidiary of Millennium ('Millennium America'), and guaranteed by Millennium,
  consent to certain amendments or waivers under their debt indentures relating
  to the asset contribution by Millennium
 
- - Lyondell and Millennium agree on a variety of operational agreements that will
  affect the Partnership and its dealings with Lyondell and Millennium
 
- - the Partnership obtains a bank credit facility by the Closing that will allow
  it to borrow at least $1.25 billion
 
- - no events occur that are likely to have a material adverse effect on the
  businesses contributed by Lyondell and Millennium, except for events that
  affect the entire petrochemicals industry and affect the two businesses in a
  similar way.
 
TERMINATION OF THE JOINT VENTURE TRANSACTION (PAGE 57)
 
     The Boards of Directors of our companies can jointly agree to terminate the
Master Transaction Agreement (and, therefore, abandon the Joint Venture
Transaction) at any time prior to
 
                                       8
 <PAGE>
<PAGE>
Closing. Either company, acting alone, can terminate the Master Transaction
Agreement (and, therefore, abandon the Joint Venture Transaction) if:
 
- - the other company made certain misrepresentations in the Master Transaction
  Agreement or does not honor certain covenants in the Master Transaction
  Agreement
 
- - a court or governmental authority has prohibited the Joint Venture Transaction
 
- - the Closing does not occur on or before March 31, 1998
 
- - the other company accepts (or recommends that its stockholders accept) another
  offer that would be materially inconsistent with or preclude the Joint Venture
  Transaction
 
- - it determines that another offer would be materially more favorable from a
  financial point of view to you or to the company, or
 
- - new owners gain control of the other company.
 
     If either company terminates the Master Transaction Agreement because the
other company has accepted a better offer or has undergone a change in control,
it will receive a $40 million termination fee from the other company. Similarly,
if either company terminates the Master Transaction Agreement in order to accept
a better offer itself, it will have to pay a $40 million termination fee to the
other company. Each company must also pay a termination fee if it terminates the
Master Transaction Agreement and, within 180 days after termination, it sells
its petrochemicals businesses or undergoes a change of control. In that case,
the fee would be either $10 million or $40 million, depending on the
circumstances.
 
NO APPRAISAL RIGHTS (PAGE 28)
 
     Both of our companies are organized under Delaware law. Under Delaware law,
Lyondell and Millennium stockholders do not have the right to an appraisal of
the value of their shares in connection with the Joint Venture Transaction.
 
ACCOUNTING TREATMENT (PAGE 28)
 
     Both Lyondell and Millennium will account for their general partner
interests and limited partner interests in the Partnership on an equity basis,
effective as of the Closing.

FEDERAL INCOME TAX CONSEQUENCES OF THE JOINT VENTURE TRANSACTION (PAGE 28)
 
     The Joint Venture Transaction will have no federal income tax consequences
for the stockholders of either Lyondell or Millennium. Neither Lyondell nor
Millennium is expected to recognize gain or loss for federal income tax purposes
on the Joint Venture Transaction.
 
FORWARD-LOOKING STATEMENTS MAY PROVE INACCURATE
 
     We have each made forward-looking statements in this document (and in
documents that are incorporated by reference) that are subject to risks and
uncertainties. Forward-looking statements include information concerning the
possible or assumed future results of operations of the businesses contributed
by Lyondell and Millennium and the Partnership. Also, when we use words such as
'believe,' 'expect,' 'anticipate' or similar expressions, we are making
forward-looking statements. Stockholders should note that many factors, some of
which are discussed elsewhere in this document and in the documents which we
incorporate by reference, could affect the future financial results of the
businesses contributed by Lyondell and Millennium and the Partnership and could
cause their actual future results to differ materially from those anticipated in
our forward-looking statements. These factors include the following:
 
- - the balance between industry production capacity and operating rates, on the
  one hand, and demand for our products, such as ethylene and polyethylene, on
  the other hand
 
- - the economic trends in the United States and other countries which are
  marketplaces for our products
 
- - customer inventory levels
 
- - competitive pricing pressures
 
- - the cost and availability of feedstocks and other raw materials, such as
  petroleum liquids, natural gas, natural gas liquids and ethylene
 
- - operating interruptions (including leaks, explosions, fires, mechanical
  failures, unscheduled downtime, transportation interruptions, spills, releases
  and other environmental risks)
 
- - competitive technology positions
 
                                       9
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<PAGE>
- - delays in achieving productivity improvement and cost-reduction targets or
  completing construction projects on schedule
 
- - difficulties that may be encountered in combining the two businesses, in
  achieving synergies as anticipated or in managing the businesses as a
  partnership, and
 
- - the risk that our analyses of these risks and forces could be incorrect and/or
  that the strategies developed to address them could be unsuccessful.
 
                                       10
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                            JOINT VENTURE STRUCTURE
 
     The following chart shows the structural relationship of the Partnership,
Lyondell, Millennium and other affiliated entities.

[GRAPHIC REPRESENTATION  of the following structural relationship:

LYONDELL owns 75% of Lyondell Methanol Company, L.P., 60% of Lyondell-Citgo
Refining Company Ltd., and 100% of each of Lyondell LP and Lyondell GP.

Lyondell LP and Lyondell GP in turn own 55.86% and 1.14% respectively of
THE PARTNERSHIP.

MILLENNIUM owns 100% of the Non-U.S. TiO2 business and 100% of Millennium
America Inc.

Millennium America Inc. owns 100% of the U.S. TiO2, TiCl4, Pigments, Silica Gel,
Fragrances and Flavors businesses and 100% of Millennium Petrochemicals Inc.

Millennium Petrochemicals Inc. owns 100% of the Acetyls business, 26.4% of
Suburban Propane Partners, L.P., and 100% of each of Millennium GP and
Millennium LP.

Millennium GP and Millennium LP in turn own 0.86% and 42.14% respectively of
THE PARTNERSHIP.

Intermediate holding companies are not shown between (i) MILLENNIUM and
the Non-U.S. TiO2 business, (ii) Millennium America Inc. and the U.S. TiO2,
TiCl4, Pigments and Silica Gel businesses and the Fragrances and Flavors
business, respectively, and (iii) Millennium Petrochemicals Inc. and the
Acetyls business and Suburban Propane Partners, L.P., respectively.]


                                       11
<PAGE>
<PAGE>
                              THE SPECIAL MEETINGS
 
GENERAL
 
     This Joint Proxy Statement is being furnished to holders of shares of
Lyondell's Common Stock, par value $1.00 per share (the 'Lyondell Common
Stock'), in connection with the solicitation of proxies by Lyondell's Board of
Directors for use at the special meeting of Lyondell's stockholders (the
'Lyondell Meeting') to be held at                          , on                ,
1997, convening at   :00 a.m., and at any adjournments or postponements thereof.
 
     This Joint Proxy Statement is also being furnished to holders of shares of
Millennium's Common Stock, par value $0.01 per share (the 'Millennium Common
Stock'), in connection with the solicitation of proxies by Millennium's Board of
Directors for use at the special meeting of Millennium's stockholders (the
'Millennium Meeting') to be held at                          , on
               , 1997, convening at   :00 a.m., and at any adjournments or
postponements thereof.
 
MATTERS TO BE CONSIDERED AT THE SPECIAL MEETINGS
 
     LYONDELL. At the Lyondell Meeting, holders of shares of Lyondell Common
Stock will be asked to consider and vote upon a proposal to approve the Joint
Venture Transaction, including the proposed contribution (the 'Lyondell Asset
Contribution') to the Partnership of substantially all of the assets comprising
Lyondell's petrochemicals and polymers businesses (the 'Lyondell Contributed
Business'), as well as a $345 million Lyondell note payable to the Partnership,
in exchange for a 57% interest in the Partnership, the assumption by the
Partnership of primary liability on $745 million in Lyondell indebtedness and
the assumption by the Partnership of certain other liabilities relating to the
Lyondell Contributed Business. At the Lyondell Meeting, you will also be asked
to consider and vote upon such other business as properly may be presented at
the Lyondell Meeting.
 
     Representatives of Coopers & Lybrand L.L.P., Lyondell's independent public
accountants, will attend the Lyondell Meeting and will have an opportunity to
make a statement and to respond to appropriate questions from stockholders.
 
     THE BOARD OF DIRECTORS OF LYONDELL HAS UNANIMOUSLY DETERMINED THAT THE
LYONDELL ASSET CONTRIBUTION IS IN THE BEST INTERESTS OF LYONDELL AND ITS
STOCKHOLDERS AND UNANIMOUSLY RECOMMENDS THAT YOU VOTE 'FOR' APPROVAL OF THE
JOINT VENTURE TRANSACTION, INCLUDING THE LYONDELL ASSET CONTRIBUTION.
 
     MILLENNIUM. At the Millennium Meeting, holders of shares of Millennium
Common Stock will be asked to consider and vote upon a proposal to approve the
Joint Venture Transaction, including the proposed contribution (the 'Millennium
Asset Contribution') by a subsidiary of Millennium, Millennium Petrochemicals
Inc. ('Millennium Petrochemicals'), to the Partnership of substantially all of
the assets comprising Millennium's polyethylene and related products,
performance polymers and ethyl alcohol businesses other than the related
accounts receivable (collectively, the 'Millennium Contributed Business' and,
together with the Lyondell Contributed Business, the 'Contributed Businesses')
in exchange for a 43% interest in the Partnership, the assumption by the
Partnership of $750 million of intercompany indebtedness payable to a subsidiary
of Millennium (the 'Millennium Contributed Debt') that will be repaid at Closing
in cash and the assumption by the Partnership of certain other liabilities
related to the Millennium Petrochemicals business. In addition, at the Closing,
Millennium America, a subsidiary of Millennium, will guarantee $750 million of
the Partnership's debt (the 'Millennium America Guarantee'). At the Millennium
Meeting, you will also be asked to consider and vote upon such other business as
properly may be presented at the Millennium Meeting.
 
     Representatives of Price Waterhouse LLP, Millennium's independent public
accountants, will attend the Millennium Meeting and will have an opportunity to
make a statement and to respond to appropriate questions from stockholders.
 
     THE BOARD OF DIRECTORS OF MILLENNIUM HAS UNANIMOUSLY DETERMINED THAT THE
MILLENNIUM ASSET CONTRIBUTION IS IN THE BEST INTERESTS OF MILLENNIUM AND ITS
STOCKHOLDERS AND UNANIMOUSLY RECOMMENDS THAT YOU VOTE 'FOR' APPROVAL OF THE
JOINT VENTURE TRANSACTION, INCLUDING THE MILLENNIUM ASSET CONTRIBUTION.
 
                                       12
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RECORD DATE; QUORUM; VOTING AT THE MEETINGS
 
     LYONDELL. Lyondell's Board of Directors has fixed the close of business on
               , 1997 as the record date (the 'Lyondell Record Date') for the
Lyondell Meeting. Accordingly, only holders of record of shares of Lyondell
Common Stock at the Lyondell Record Date are entitled to notice of and to vote
at the Lyondell Meeting. At the Lyondell Record Date, there were 80,000,000
shares of Lyondell Common Stock outstanding, held by approximately       holders
of record. Each share of Lyondell Common Stock is entitled to one vote on each
matter to be acted upon at the Lyondell Meeting. The presence, either in person
or by proxy, of the holders of a majority of the outstanding shares of Lyondell
Common Stock entitled to vote at the Lyondell Meeting is necessary to constitute
a quorum. Abstentions (including broker non-votes) are included in the
calculation of the number of votes represented at the Lyondell Meeting for
purposes of determining whether a quorum has been achieved.
 
     Section 271 of the Delaware General Corporation Law (the 'DGCL') requires
that a 'sale, lease or exchange' of 'all or substantially all' of the assets of
a Delaware corporation be approved by the stockholders of the corporation.
Lyondell is a Delaware corporation. Although there is some uncertainty under the
statute and case law as to the applicability of Section 271 to the Lyondell
Asset Contribution, the Lyondell assets to be transferred to the Partnership may
be deemed to constitute 'substantially all' of Lyondell's assets and the
transfer may be deemed to constitute a 'sale, lease or exchange' for such
purpose. Accordingly, and as a matter of good corporate governance, Lyondell has
conditioned its obligation to consummate the Joint Venture Transaction upon
approval by the holders of a majority of the outstanding shares of Lyondell
Common Stock.
 
     Because the affirmative vote of the holders of a majority of the
outstanding shares of Lyondell Common Stock entitled to vote thereon is
necessary to approve the Joint Venture Transaction, including the Lyondell Asset
Contribution, failures to vote and broker non-votes will have the practical
effect of voting 'AGAINST' the Joint Venture Transaction. As more fully
described under 'Proxies' below, shares of Lyondell Common Stock represented by
properly executed proxies received at or prior to the Lyondell Meeting that have
not been revoked will be voted at the Lyondell Meeting in accordance with the
instructions contained therein or, if no instruction is provided, will be voted
'FOR' the approval of the Joint Venture Transaction.
 
     To the knowledge of Lyondell, the directors and executive officers of
Lyondell, who, as of the Lyondell Record Date, beneficially held in the
aggregate less than 1% of the outstanding shares of Lyondell Common Stock,
intend to vote in favor of the approval of the Joint Venture Transaction.
 
     MILLENNIUM. Millennium's Board of Directors has fixed the close of business
on                , 1997 as the record date (the 'Millennium Record Date') for
the Millennium Meeting. Accordingly, only holders of record of shares of
Millennium Common Stock at the Millennium Record Date are entitled to notice of
and to vote at the Millennium Meeting. At the Millennium Record Date, there were
77,089,378 shares of Millennium Common Stock outstanding, held by approximately
      holders of record. Each share of Millennium Common Stock is entitled to
one vote on each matter to be acted upon at the Millennium Meeting. The
presence, either in person or by proxy, of a majority of the outstanding shares
of Millennium Common Stock entitled to be voted at the Millennium Meeting is
necessary to constitute a quorum. Abstentions (including broker non-votes) are
included in the calculation of the number of votes represented at the Millennium
Meeting for purposes of determining whether a quorum has been achieved.
 
     Millennium believes that stockholder approval of the Joint Venture
Transaction, including the Millennium Asset Contribution, is not required under
Delaware law because the Millennium Asset Contribution by Millennium
Petrochemicals does not, in Millennium's opinion, constitute a sale, lease or
exchange by Millennium of 'all or substantially all' of the assets of Millennium
within the meaning of Section 271 of the DGCL. However, by requiring the
approval of the holders of a majority of the shares of outstanding Millennium
Common Stock, the statutory voting requirement, which would be compulsory if
Section 271 of the DGCL were applicable, will be satisfied in any event.
Accordingly, and as a matter of good corporate governance, Millennium has
conditioned its obligation to consummate the Joint Venture Transaction upon
approval by the holders of a majority of the outstanding shares of Millennium
Common Stock.
 
                                       13
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<PAGE>
     Because the affirmative vote of the holders of a majority of the
outstanding shares of Millennium Common Stock entitled to vote thereon is
necessary to approve the Joint Venture Transaction, including the Millennium
Asset Contribution, abstentions, failures to vote and broker non-votes will have
the practical effect of voting 'AGAINST' the Joint Venture Transaction. As more
fully described under 'Proxies' below, shares of Millennium Common Stock
represented by properly executed proxies received at or prior to the Millennium
Meeting that have not been revoked will be voted at the Millennium Meeting in
accordance with the instructions contained therein or, if no instruction is
provided, will be voted 'FOR' the approval of the Joint Venture Transaction.
 
     To the knowledge of Millennium, the directors and executive officers of
Millennium, who, as of the Millennium Record Date, beneficially held
approximately 2.6% of the outstanding shares of Millennium Common Stock, intend
to vote in favor of the approval of the Joint Venture Transaction.
 
PROXIES
 
     This Joint Proxy Statement is being furnished to holders of Lyondell Common
Stock and Millennium Common Stock in connection with the solicitation of proxies
by and on behalf of the respective Boards of Directors of Lyondell and
Millennium for use at the Lyondell Meeting and the Millennium Meeting, as the
case may be.
 
     LYONDELL. Shares of Lyondell Common Stock represented by properly executed
proxies received at or prior to the Lyondell Meeting that have not been revoked
will be voted at the Lyondell Meeting in accordance with the instructions
contained therein. Shares of Lyondell Common Stock represented by properly
executed proxies for which no instruction is provided will be voted 'FOR' the
approval of the Lyondell Asset Contribution. Holders of Lyondell Common Stock
are requested to complete, sign, date and return promptly the enclosed proxy
card in the postage-prepaid envelope provided for such purpose to ensure that
their shares are voted. Any holder of record of Lyondell Common Stock who so
desires may revoke his, her or its proxy at any time prior to the time it is
exercised by (i) providing written notice to such effect to the Secretary of
Lyondell, (ii) giving a duly executed proxy bearing a date subsequent to that of
a previously furnished proxy or (iii) attending the Lyondell Meeting and voting
in person. Attendance at the Lyondell Meeting will not in itself constitute a
revocation of a previously furnished proxy. Stockholders who attend the Lyondell
Meeting in person need not revoke their proxy (if previously furnished) to vote
in person.
 
     If the Lyondell Meeting is postponed or adjourned for any reason, at any
subsequent reconvening of the Lyondell Meeting, all proxies will be voted in the
same manner as such proxies would have been voted at the initial convening of
the Lyondell Meeting (except for any proxies that have been effectively revoked
or withdrawn), notwithstanding that they may have been effectively voted on the
same or any other matter at a previous meeting.
 
     If any other matters are properly presented at the Lyondell Meeting for
consideration, including consideration of a motion to adjourn the Lyondell
Meeting to another time and/or place (including for the purpose of soliciting
additional proxies), the persons named in the enclosed form of proxy and acting
thereunder will have discretion to vote on such matters in accordance with their
best judgment; provided, however, that any proxy marked 'AGAINST' will not be
voted in favor of any such motion to adjourn.
 
     If any beneficial owner of Lyondell Common Stock holds such stock in
'street name' and wishes to vote such stock at the Lyondell Meeting, such owner
must obtain from the relevant nominee holding such stock a properly executed
'legal proxy' which (i) identifies the beneficial owner as a holder of such
stock, (ii) authorizes the beneficial owner to act on behalf of the
nominee-record owner at the Lyondell Meeting and (iii) identifies the number of
shares (and certificate numbers, if applicable) in respect of which the
authorization is granted.
 
     MILLENNIUM. Shares of Millennium Common Stock represented by properly
executed proxies received at or prior to the Millennium Meeting that have not
been revoked will be voted at the Millennium Meeting in accordance with the
instructions contained therein. Shares of Millennium Common Stock represented by
properly executed proxies for which no instructions are provided will be voted
'FOR' the approval of the Millennium Asset Contribution. Holders of Millennium
Common
 
                                       14
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Stock are requested to complete, sign, date and return promptly the enclosed
proxy card in the postage-prepaid envelope provided for such purpose to ensure
that their shares are voted. Any holder of record of Millennium Common Stock who
so desires may revoke his, her or its proxy at any time prior to the time it is
exercised by (i) providing written notice to such effect to the Secretary of
Millennium, (ii) giving a duly executed proxy bearing a date subsequent to that
of a previously furnished proxy or (iii) attending the Millennium Meeting and
voting in person. Attendance at the Millennium Meeting will not in itself
constitute a revocation of a previously furnished proxy. Stockholders who attend
the Millennium Meeting in person need not revoke their proxy (if previously
furnished) to vote in person.
 
     If the Millennium Meeting is postponed or adjourned for any reason, at any
subsequent reconvening of the Millennium Meeting all proxies will be voted in
the same manner as such proxies would have been voted at the initial convening
of the Millennium Meeting (except for any proxies that have been effectively
revoked or withdrawn), notwithstanding that they may have been effectively voted
on the same or any other matter at a previous meeting.
 
     If any other matters are properly presented at the Millennium Meeting for
consideration, including consideration of a motion to adjourn the Millennium
Meeting to another time and/or place (including for the purpose of soliciting
additional proxies), the persons named in the enclosed form of proxy and acting
thereunder will have discretion to vote on such matters in accordance with their
best judgment; provided, however, that any proxy marked 'AGAINST' will not be
voted in favor of any such motion to adjourn.
 
     If any beneficial owner of Millennium Common Stock holds such stock in
'street name' and wishes to vote such stock at the Millennium Meeting, such
owner must obtain from the relevant nominee holding such stock a properly
executed 'legal proxy' which (i) identifies the beneficial owner as a holder of
such stock, (ii) authorizes the beneficial owner to act on behalf of the
nominee-record owner at the Millennium Meeting and (iii) identifies the number
of shares (and certificate numbers, if applicable) in respect of which the
authorization is granted.
 
     SOLICITATION EFFORTS. Lyondell and Millennium will share the cost of
soliciting proxies from the holders of Lyondell Common Stock and Millennium
Common Stock, including the cost of preparing and mailing this Joint Proxy
Statement, in accordance with their respective interests in the Partnership. In
addition to solicitation by mail, directors, officers and employees of Lyondell
and Millennium may solicit proxies by telephone, facsimile transmission or
otherwise. Such directors, officers and employees of Lyondell and Millennium
will not be specially compensated for such solicitation, but may be reimbursed
for out-of-pocket expenses incurred in connection therewith. Brokerage firms,
fiduciaries and other custodians who forward soliciting material to the
beneficial owners of Lyondell Common Stock or Millennium Common Stock will be
reimbursed for their reasonable expenses incurred in forwarding such material.
Lyondell and Millennium have retained Georgeson & Company Inc., at a cost of
$25,000, plus reimbursement of out-of-pocket expenses, to assist in the
solicitation of proxies from brokers, nominees, institutions and individuals.
Arrangements also will be made with custodians, nominees and fiduciaries for the
forwarding of proxy solicitation materials to beneficial owners of shares of
Lyondell Common Stock and Millennium Common Stock held of record by such
custodians, nominees and fiduciaries, and Lyondell and Millennium will reimburse
such custodians, nominees and fiduciaries for their reasonable out-of-pocket
expenses incurred in connection therewith.
 
                                       15
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                           THE PROPOSED JOINT VENTURE
 
BACKGROUND
 
     Since its inception as a division (the 'Lyondell Division') of Atlantic
Richfield Company ('ARCO') in 1985, one of Lyondell's major ethylene customers
has been Millennium Petrochemicals. Prior to March 3, 1997, Millennium
Petrochemicals was named Quantum Chemical Corporation ('Quantum'). Quantum was
an independent public company until September 30, 1993, when it was acquired by
Hanson PLC ('Hanson'). As part of the October 1, 1996 Demerger of Hanson
described below, Quantum became an indirect, wholly-owned subsidiary of
Millennium and Millennium became an independent publicly traded corporation.
 
     As a result of their customer-supplier relationship, there have been
numerous contacts between Millennium Petrochemicals and Lyondell in the ordinary
course of business for many years. In addition, Lyondell and Millennium
Petrochemicals participated in a feasibility study with another company
concerning a possible jointly owned olefins plant and have had numerous meetings
in connection with this project. Senior managements of Millennium Petrochemicals
(or its parent company) and Lyondell also have had general discussions with each
other from time to time, often at industry trade association meetings.
 
     During the first half of 1988, the management of the Lyondell Division
recommended to ARCO's senior management that ARCO consider initiating a
transaction that would result in a business combination between Lyondell and
Quantum. This recommendation was based on the perceived synergies and cost
savings that could be derived from a combination of the two businesses. ARCO's
management declined to pursue this recommendation, and ARCO elected to proceed
with a public offering of Lyondell Common Stock. In January 1989, ARCO completed
an initial public offering of approximately 50.1% of the outstanding shares of
Lyondell Common Stock.
 
     Following Lyondell's initial public offering and prior to June 1993, the
management of Lyondell analyzed a number of strategic alternatives pursuant to
which Lyondell might be able to effect a business combination with Quantum. This
analysis also was motivated by the perceived synergies and cost savings that
could be derived from a combination of the two businesses. In June 1993, senior
executives of Quantum and Lyondell agreed to form a team for the purpose of
exploring how the two businesses could be combined. This planning project was
never launched, however, because on June 30, 1993, Quantum and Hanson announced
the execution of a merger agreement pursuant to which Quantum would become a
wholly-owned subsidiary of Hanson. The acquisition of Quantum by Hanson was
completed on September 30, 1993, and Quantum was operated as a subsidiary of
Hanson until October 1, 1996, as described below.
 
     During the latter part of 1993, ARCO, acting through an investment bank,
communicated with Hanson, among others, regarding the possibility of Hanson,
among others, acquiring ARCO's interest in Lyondell. In response, Hanson
indicated that it did not wish to pursue such a possibility at that time because
it was still concentrating on the integration of Quantum's business. During the
first half of 1994 at a meeting unrelated to Lyondell, a Hanson executive
indicated to one of Lyondell's directors that while Hanson's current priority
was the assimilation of Quantum, Hanson might be interested in pursuing some
form of business combination with Lyondell in the future.
 
     During the first half of 1994, ARCO and Lyondell commenced work on an
offering of three-year ARCO notes that would be exchangeable upon maturity into
Lyondell Common Stock or cash of equal value. The ARCO note offering was
completed in August 1994. Prior to the completion of the ARCO note offering,
Hanson contacted ARCO regarding the possibility of Hanson acquiring ARCO's
interest in Lyondell. In response, ARCO indicated that it was unwilling to
consider Hanson's proposal because it intended to proceed with the ARCO note
offering.
 
     In June 1995, senior executives of Hanson and Quantum approached Lyondell
concerning the possibility of exploring an acquisition of Lyondell for cash. On
June 22, 1995, Lyondell and Hanson entered into a confidentiality and standstill
agreement. Thereafter, Lyondell furnished Hanson with certain information
regarding Lyondell and its business, and senior representatives of Lyondell and
Hanson met to review such information. On July 12, 1995, Lyondell retained
Salomon Brothers Inc ('Salomon') to act as financial advisor to Lyondell in
connection with the inquiry by Hanson.
 
                                       16
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     At a Lyondell Board of Directors meeting on July 20-21, 1995, Lyondell's
Board discussed Hanson's expression of interest and authorized Lyondell's
management to continue discussions with Hanson. Following the Lyondell Board
meeting, representatives of Hanson conducted various due diligence meetings with
representatives of Lyondell and Salomon. These discussions did not go beyond the
preliminary stage and were terminated by Hanson in September 1995.
 
     In October 1995, Lyondell initiated discussions with Hanson regarding the
possibility of an acquisition of Quantum by Lyondell. The companies exchanged
certain information and held various meetings to discuss valuation and
structural issues.
 
     In January 1996, Hanson announced its intention to demerge (i.e., spin-off)
Quantum and its other chemical businesses by transferring them to a new
corporation (subsequently named Millennium) whose shares would be distributed as
a pro rata dividend-in-kind to Hanson's shareholders (the 'Demerger'). In early
1996, representatives of Lyondell and Salomon pursued discussions about an
acquisition of Quantum (for a combination of cash and Lyondell Common Stock)
with representatives of Hanson. These discussions were terminated by Hanson in
favor of pursuing the Demerger.
 
     In May 1996, Lyondell asked Hanson to consider a transaction that would
have, among other things, resulted in Lyondell acquiring Quantum for cash. In
August 1996, a representative of Salomon contacted Hanson to inquire again
regarding a possible acquisition of Quantum by Lyondell. In response to each
inquiry, Hanson indicated that it believed the proposed Demerger was in the best
interests of its shareholders.
 
     On October 1, 1996, the Demerger was effected and Millennium Common Stock
began trading on the New York Stock Exchange.
 
     In January 1997, senior management of Lyondell and Millennium decided to
explore various alternatives for combining the Contributed Businesses of the two
companies. In furtherance of this, in February 1997 Lyondell and Millennium
executed a confidentiality and standstill agreement.
 
     From March through mid-June 1997, representatives of Lyondell and
Millennium exchanged information and held meetings focused on the value of
potential synergies (including cost savings and manufacturing efficiencies) that
might be achieved through a combination of the Contributed Businesses, relative
asset values, historical results, financial and operating data and structure of
the Joint Venture Transaction. By mid-June the parties had determined to pursue
a joint venture and had reached preliminary agreement on their respective
contributions and relative ownership percentages.
 
     Throughout this period, Lyondell's Board had been actively discussing
Lyondell's strategic plan and the Board was updated on the status of discussions
with Millennium at its March and May regular Board meetings. On April 23, 1997,
at a regular meeting, Millennium's management advised the Millennium Board of
Directors of the status of the discussions with Lyondell. The Millennium Board
also reviewed Millennium Petrochemicals' five-year strategic plan with
Millennium Petrochemicals' management. On June 25, 1997, at a special meeting,
the Lyondell Board discussed the status of the negotiations with Millennium.
 
     On June 26, 1997, Lyondell entered into a new engagement letter retaining
Salomon to act as Lyondell's financial advisor specifically in connection with
the proposed joint venture.
 
     From mid-June to July 23, 1997, representatives of Lyondell and Millennium
held a series of meetings and discussions to negotiate the terms of the Master
Transaction Agreement, the Asset Contribution Agreements, the Partnership
Agreement and the Parent Agreement. Concurrently, senior management of the two
companies held additional discussions about business prospects, tax
considerations and proposed management and other human resource issues.
 
     Pursuant to an engagement letter dated July 1, 1997, Millennium retained
J.P. Morgan Securities Inc. ('J.P. Morgan') to render a fairness opinion in
connection with the proposed joint venture.
 
     On Wednesday, July 23, 1997, at a regular meeting, the Millennium Board
considered the proposed joint venture and received the opinion of J.P. Morgan as
described below. On Thursday, July 24, 1997, at a resumption of the Board
meeting, the Board of Directors of Millennium unanimously approved the
transaction. See ' -- Opinion of Financial Advisor to Millennium' below.
 
     On Friday, July 25, 1997, at a regular meeting, the Lyondell Board of
Directors considered the proposed joint venture. At that meeting, during which
the opinion of Salomon was received as
 
                                       17
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described below, the Board of Directors of Lyondell unanimously approved the
transaction. See ' -- Opinion of Financial Advisor to Lyondell' below.
 
     Over the weekend, Lyondell and Millennium resolved remaining open issues
regarding the Master Transaction Agreement and related agreements and then
executed and delivered the Master Transaction Agreement.
 
     At the opening of business on Monday, July 28, 1997, Lyondell and
Millennium issued a joint press release announcing the proposed Joint Venture
Transaction.
 
REASONS FOR THE JOINT VENTURE TRANSACTION
 
     GENERAL. Lyondell and Millennium believe the Joint Venture Transaction
represents a logical extension of both companies' strategic plans to enhance
stockholder value. It will provide opportunities for significant costs savings
and expanded business opportunities that should lead to improved earnings and
cash flow from the contributed businesses and therefore improved stockholder
returns for both companies. Both Lyondell and Millennium are leading low-cost
producers of ethylene and polyethylene. Lyondell is the largest combined
producer of ethylene and propylene in North America and a significant producer
of polyethylene. Millennium is the largest producer of polyethylene in the
United States and a significant producer of ethylene. By combining Lyondell's
and Millennium's respective petrochemicals businesses, Lyondell and Millennium
expect that the Partnership, upon its formation, will be the largest producer of
ethylene and polyethylene in North America. In addition, they expect the
Partnership will be positioned to (i) become the petrochemicals industry's
low-cost producer of ethylene and polyethylene, (ii) expand into new markets and
new geographic areas with a broader array of petrochemicals products than are
currently offered by either Lyondell or Millennium separately and (iii) utilize
both Lyondell's and Millennium's proprietary technology for new product
development.
 
     Following the combination of the Lyondell Contributed Business and the
Millennium Contributed Business, the Partnership expects to realize significant
cost benefits and savings (the 'Synergies') compared to the aggregate cost to
Lyondell and Millennium of operating such businesses separately. Among other
things, the projected Synergies include various manufacturing efficiencies, such
as (i) improved operating rates during adverse fluctuations in the ethylene
industry cycle, as a result of the integration of Lyondell's and Millennium's
ethylene and polyethylene operations; (ii) lower production costs achieved by
optimizing the purchase and deployment of feedstocks across three Gulf Coast
olefin plants; (iii) expanding the upgrade of co-products by taking advantage of
the enhanced processing capability at Lyondell's olefins facility; (iv)
optimizing production schedules of the polymers plants by dedicating particular
plants or equipment to the production of specific resin products; (v) lower
storage fees; and (vi) additional efficiencies achieved by utilizing the most
effective manufacturing practices developed by Lyondell and Millennium.
 
     In addition, Lyondell and Millennium expect the Synergies to include
logistics and distribution efficiencies. For example, through the Partnership
they expect to consolidate Lyondell's and Millennium's product distribution
systems and optimize their efficiency. They also expect the Partnership to
benefit from lower aggregate transportation costs by obtaining reduced freight
rates and optimizing the use of rail cars.
 
     Lyondell and Millennium also expect to create considerable value in the
Partnership by consolidating their staffing and services. For example, a single,
experienced executive management team will manage the Contributed Businesses
rather than the two independent teams currently in place at Lyondell and
Millennium. In addition, the Partnership expects to (i) reduce or eliminate
duplicative overhead and staffing costs, (ii) consolidate Lyondell's and
Millennium's petrochemicals and polymers sales and marketing staffs, (iii)
consolidate Lyondell's and Millennium's research and development programs and
(iv) increase the efficient utilization of specialized plant personnel by
multiple plants.
 
     As a result of the Joint Venture Transaction, Millennium and Lyondell
expect that they should be able to achieve at least $150 million per year
(before tax) of Synergies. The full effect of these Synergies is not expected to
be realized until the year 2000. Based on the current number of shares
outstanding of each Lyondell and Millennium, the full after-tax impact on annual
income per share of these Synergies would be $0.68 for Lyondell and $0.48 for
Millennium. The unaudited pro forma financial data of the Partnership in this
Joint Proxy Statement do not reflect the impact of anticipated Synergies (other
than
 
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anticipated reduced interest rates on new Partnership debt). See 'Selected
Historical and Unaudited Pro Forma Financial Data of Lyondell, Millennium and
the Partnership -- Introduction.'
 
     Given the inherent risks and difficulties in combining businesses such as
the Contributed Businesses, there can be no assurance that the aggregate amount
of the Synergies will equal $150 million or that any or all of the Synergies
will be realized in the timeframe anticipated. The Joint Venture Transaction
involves the integration of entities that have previously operated independently
and therefore the integration of the Contributed Businesses will require the
dedication of significant management resources. The difficulties of combining
the entities' operations may be exacerbated by the necessity of coordinating
geographically separated organizations, integrating personnel with disparate
business backgrounds and combining different financial reporting systems,
processes and corporate cultures. The process of integrating operations could
cause an interruption of, or loss of momentum in, the activities of the combined
enterprise's business, including any anticipated growth. Difficulties
encountered in connection with implementing the Joint Venture Transaction could
have a material adverse effect on the business, results of operations or
financial condition of the Partnership.
 
     Moreover, the analyses employed to develop estimates of potential Synergies
were necessarily based upon various assumptions that involve judgments regarding
future economic and competitive conditions, inflation rates, interest rates and
financial market conditions, all of which are difficult to predict and many of
which are beyond the control of Lyondell and Millennium. In view of historical
cyclicality of the relevant industries, there can be no assurance that the
positive effects of the Synergies will not be offset, in whole or in part, by
deteriorating industry conditions. In addition, the Joint Venture Transaction
will result in one-time charges to the Partnership, Lyondell and Millennium,
primarily as a result of severance and relocation costs currently estimated at
approximately $60 million. Also, capital expenditures approximating $95 million
will have to be made to obtain certain of the Synergies.
 
     LYONDELL. Lyondell believes that the Joint Venture Transaction will benefit
Lyondell by providing the means to achieve significant cost savings and
manufacturing efficiencies in its core petrochemicals and polymers businesses.
These cost savings and efficiencies are expected to improve earnings and cash
flow beginning in 1998 and continuing thereafter, thereby materially enhancing
stockholder returns for Lyondell. Lyondell's strategy has been to maintain its
low cost position, to reduce cyclicality in its business and to grow its
business. The Joint Venture Transaction supports all three elements of
Lyondell's strategy. The Partnership's business is expected to be the largest
producer of ethylene and polyethylene in North America, providing the
opportunity to leverage Lyondell's low cost position over a much larger asset
base. The increased ethylene integration expected to be achieved over the next
several years should somewhat mitigate the impact of industry downturns. In
addition, because the end use markets for Lyondell's and Millennium's polymers
products do not significantly overlap, the Partnership will have a much broader
polymer product mix, and this should improve the ability to satisfy customer
needs. The Joint Venture Transaction also will provide a stronger platform for
continued growth of the Contributed Businesses.
 
     MILLENNIUM. Millennium believes that its participation in the Partnership
will add to its earnings commencing in 1998 and that the Joint Venture
Transaction will increase the economic value of Millennium. Through its
ownership interest in the Partnership, Millennium will share in the cost savings
resulting from the Synergies. In addition, Millennium will receive $750 million
in cash at Closing from the Partnership's repayment of the Millennium
Contributed Debt, and an additional $250 million through collection of accounts
receivable retained by Millennium. Millennium will apply these proceeds to
reduce its bank debt by approximately $1 billion. Taking into account
Millennium's 43% share of the Partnership's expected debt of $1.745 billion, net
of Millennium's 43% share of the $345 million note from Lyondell, Millennium's
consolidated indebtedness will decrease by approximately $400 million, giving
Millennium a pro forma debt to capitalization ratio as of June 30, 1997 of
approximately 52% (compared to 57% before the Joint Venture Transaction). Taking
into account Millennium's 43% share of the Partnership's expected debt of $1.745
billion, Millennium's consolidated indebtedness will decrease by approximately
$250 million, giving Millennium a pro forma debt to capitalization ratio as of
June 30, 1997 of approximately 54%. Alternatively, taking into account the
Millennium America Guarantee, Millennium's consolidated indebtedness will
decrease by approximately $250 million.
 
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Millennium expects that this leverage improvement will increase financial
flexibility as it pursues its strategy of developing its acetyls, TiO2, TiCl4,
pigments, silica gels and fragrances and flavors businesses.
 
RECOMMENDATION OF THE LYONDELL BOARD OF DIRECTORS
 
     At a meeting of Lyondell's Board of Directors held on July 25, 1997, the
Board of Directors of Lyondell unanimously determined that the Joint Venture
Transaction is in the best interests of Lyondell and its stockholders,
unanimously approved the Joint Venture Transaction and unanimously recommended
that holders of Lyondell Common Stock vote 'FOR' approval of the Joint Venture
Transaction.
 
RECOMMENDATION OF THE MILLENNIUM BOARD OF DIRECTORS
 
     At a meeting of Millennium's Board of Directors held on July 23 and 24,
1997, the Board of Directors of Millennium unanimously determined that the Joint
Venture Transaction is in the best interests of Millennium and its stockholders,
unanimously approved the Joint Venture Transaction and unanimously recommended
that holders of Millennium Common Stock vote 'FOR' approval of the Joint Venture
Transaction.
 
OPINION OF FINANCIAL ADVISOR TO LYONDELL
 
     At the meeting of the Lyondell Board on July 25, 1997, at which the
Lyondell Board approved the Master Transaction Agreement and the ancillary
agreements, Salomon delivered its written opinion to the effect that, as of such
date, the allocation of 57% of the equity ownership in the Partnership to
Lyondell and 43% of the equity ownership in the Partnership to Millennium (the
'Allocation') was fair to Lyondell from a financial point of view. No
limitations were imposed by the Lyondell Board upon Salomon with respect to the
investigations made or the procedures followed by Salomon in rendering its
opinion, other than the confidentiality agreement described below.
 
     The full text of the written opinion of Salomon, dated July 25, 1997, is
set forth as Annex A to this Joint Proxy Statement and sets forth the
assumptions made, procedures followed, matters considered and limitations on the
scope of the review undertaken by Salomon. Lyondell stockholders are urged to
read the opinion in its entirety. Salomon's opinion is directed only to the
fairness, from a financial point of view, of the Allocation and does not
constitute a recommendation concerning how such stockholders should vote at the
Lyondell Meeting. The summary of the opinion of Salomon set forth in this Joint
Proxy Statement is qualified in its entirety by reference to the full text of
such opinion.
 
     In connection with rendering its opinion, Salomon reviewed and analyzed,
among other things, certain publicly available information concerning Lyondell,
Millennium, the Lyondell Contributed Business and the Millennium Contributed
Business and certain other financial information concerning Lyondell,
Millennium, the Lyondell Contributed Business and the Millennium Contributed
Business that was provided to Salomon by Lyondell and Millennium. Salomon
reviewed financial forecasts for the Lyondell Contributed Business that were
provided by Lyondell, as well as financial forecasts for the Millennium
Contributed Business that were provided by each of Lyondell and Millennium.
Salomon discussed the past and current business operations, financial condition
and prospects of the Lyondell Contributed Business and the Millennium
Contributed Business with certain officers and employees of Lyondell and
Millennium, respectively. Salomon also considered such other information,
financial studies, analyses, investigations and financial, economic and market
criteria that Salomon deemed relevant.
 
     In connection with its analysis of the Lyondell Asset Contribution and
rendering its opinion, Salomon was subject to an agreement with Millennium that
prohibited Salomon from disclosing to Lyondell, Lyondell's Board or management
certain information, including financial forecasts, received by Salomon from
Millennium and related to the Millennium Contributed Business. This agreement,
which was entered into at the request of Lyondell and with Lyondell's approval,
was entered into to ensure that competitively sensitive information about
Millennium would not be disclosed to Lyondell if the Joint Venture Transaction
did not close.
 
     In Salomon's review and analysis and in arriving at its opinion, Salomon
assumed and relied upon the accuracy and completeness of the information
reviewed for the purpose of its opinion, and Salomon did not assume any
responsibility for independent verification of such information. With respect to
the
 
                                       20
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financial forecasts for the Lyondell Contributed Business, Salomon assumed that
they were reasonably prepared on bases reflecting the best currently available
estimates and judgments of the management of Lyondell, and Salomon expressed no
opinion with respect to such forecasts or the assumptions on which they are
based. With respect to the financial forecasts for the Millennium Contributed
Business prepared by Millennium, Salomon assumed that they were reasonably
prepared on bases reflecting the best currently available estimates and
judgments of the management of Millennium, and Salomon expressed no opinion with
respect to such forecasts or the assumptions on which they are based. Salomon
did not make, obtain or assume any responsibility for making or obtaining any
independent evaluations or appraisals of any of the assets (including properties
and facilities) or liabilities of Lyondell or Millennium.
 
     Salomon's opinion necessarily was based upon conditions as they existed and
could be evaluated on the date of its opinion. Salomon's opinion did not address
Lyondell's underlying business decision to implement the Joint Venture
Transaction, nor did it address the terms of the Partnership Agreement other
than the Allocation.
 
     The following is a summary of the report (the 'Salomon Report') presented
by Salomon to the Lyondell Board of Directors in connection with rendering its
opinion:
 
          EQUITY VALUE CONTRIBUTED ANALYSIS. Salomon calculated a range of gross
     values for the businesses being contributed (the 'Gross Asset Values') to
     the Partnership by each of Lyondell and Millennium. This range was $1.75
     billion to $2.15 billion for Lyondell and $2.1 billion to $2.5 billion for
     Millennium. From each company's Gross Asset Value, Salomon subtracted the
     value of the assets retained and added the value of the liabilities
     retained by each company, arriving at a value range for the assets
     contributed by each of Lyondell and Millennium (the 'Asset Value
     Contributed'). From each company's Asset Value Contributed, Salomon
     subtracted the debt and added the notes receivable contributed to the
     Partnership, arriving at equity value ranges for the Contributed Businesses
     (the 'Equity Value Contributed'). The calculated range of Equity Value
     Contributed was $1.756 to $2.156 billion for Lyondell and $1.328 to $1.728
     billion for Millennium. Using these Equity Value Contributed calculations,
     Salomon arrived at Lyondell's implied percentage ownership in the
     Partnership of 50% to 62%.
 
          EBITDA CONTRIBUTION ANALYSIS. Salomon reviewed the relative EBITDA
     (earnings before interest, taxes, depreciation and amortization)
     contribution, taking into account certain leverage adjustments, from each
     of the Contributed Businesses. The analysis was based on historical and
     projected results between 1994 and 2002 (the projected results were based
     on Lyondell's projections for the Contributed Businesses). The EBITDA
     contribution from the Lyondell Contributed Business was between 53% and 57%
     for the years 1994 to 1996 and 50% to 56% for the years 1997 to 2002.
 
          In reaching its views on the range of the Gross Asset Values used in
     its Equity Value Contributed Analysis, Salomon considered the following
     analyses (which were summarized in the Salomon Report):
 
          PUBLIC MARKET VALUATION. Salomon calculated the implied public value
     of each of the Lyondell Contributed Business and the Millennium Contributed
     Business. Salomon subtracted from the firm value (i.e., market value of
     equity plus total debt plus minority interest minus cash) of each of
     Lyondell and Millennium an estimated value, calculated as a multiple of
     EBITDA, of the businesses not contributed to the Partnership by each
     company. This difference, the implied public value of each of the Lyondell
     Contributed Business and the Millennium Contributed Business, was
     approximately $1.735 billion and $1.784 billion, respectively. Salomon
     noted that at these values the Lyondell Contributed Business and the
     Millennium Contributed Business were valued at 5.3X and 4.9X the latest
     twelve months ('LTM') EBITDA while the median multiple of firm value to LTM
     EBITDA for comparable companies (Union Carbide, Geon Company and Georgia
     Gulf Corp.) was 7.0X. Salomon further noted that the implied firm value
     multiples (based on Salomon's estimates of the range of Gross Asset Values
     and the respective Contributed Businesses' LTM EBITDA) were 5.3X to 6.5X
     for the Lyondell Contributed Business and 5.7X to 6.8X for the Millennium
     Contributed Business.
 
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          COMPARABLE ACQUISITION ANALYSIS. Salomon reviewed and analyzed the
     following acquisition transactions involving other companies in the
     petrochemicals industry that it deemed relevant: (i) Huntsman Corporation's
     pending acquisition of Rexene Corporation; (ii) Sterling Group's
     acquisition of Sterling Chemicals; (iii) Lyondell's acquisition of
     Occidental Chemical Corporation's Alathon'r' HDPE business; (iv) Hanson's
     acquisition of Quantum; (v) Huntsman Corporation's acquisition of Texaco
     Inc.'s Petrochemical Division; (vi) Mitsubishi Corporation's acquisition of
     Aristech Chemical; and (vii) Occidental Petroleum's acquisition of Cain
     Chemical. Salomon noted that no transaction reviewed was identical to the
     Joint Venture Transaction and that, accordingly, an assessment of the
     results of the following analysis necessarily involves complex
     considerations and judgments concerning differences in financial and
     operating characteristics of Lyondell and Millennium and other factors that
     would affect the acquisition value of the companies to which it is being
     compared. Among other factors, Salomon indicated that the merger and
     acquisition transaction environment varies over time because of
     macroeconomic factors such as interest rate and equity market fluctuations
     and microeconomic factors such as industry results, the business cycle and
     growth expectations. Salomon reviewed each acquiree's ratio of firm value
     to LTM EBITDA (median and mean ratio of 6.3X and 7.5X, respectively) and
     firm value to average five year trailing EBITDA (median and mean ratio of
     6.8X and 6.2X, respectively). The implied firm value multiples (based on
     the Gross Asset Values and 1996 EBITDA) were 6.2X to 7.7X for the Lyondell
     Contributed Business and 6.1X to 7.2X for the Millennium Contributed
     Business.
 
          DISCOUNTED CASH FLOW ANALYSIS. Using a discounted cash flow ('DCF')
     analysis, Salomon calculated the present value of the projected unlevered
     free cash flows for each of the Lyondell Contributed Business and the
     Millennium Contributed Business (without giving effect to the Joint Venture
     Transaction or any expected operating or other efficiencies). For each of
     the Lyondell Contributed Business and the Millennium Contributed Business,
     Salomon aggregated (i) the present value of the unlevered free cash flows
     over the five-year forecast period (as projected by Lyondell's management)
     with (ii) the present value of the range of terminal values described
     below. The range of terminal values was generally calculated by applying a
     range of multiples, 5.0X to 7.0X, to the average annual projected EBITDA of
     the Lyondell Contributed Business or the Millennium Contributed Business,
     as applicable, over the forecast period. As part of the DCF analysis,
     Salomon used a range of discount rates (11.5% to 12.5%) reflecting each
     company's weighted average cost of capital. This DCF analysis resulted in
     Gross Asset Values ranges of $1.610 to $2.131 billion for the Lyondell
     Contributed Business and $2.040 to $2.654 billion for the Millennium
     Contributed Business.
 
          REPLACEMENT COST VALUATION. Salomon reviewed the replacement cost
     estimates for the Contributed Businesses provided by Lyondell and
     Millennium, and prepared additional replacement cost estimates utilizing
     generic petrochemical plant replacement cost data published by Chem Data
     Inc. (a third party consulting firm). Employing these replacement value
     estimates and applying a discount, Salomon arrived at a range of Gross
     Asset Values equal to $1.90 to $2.25 billion for the Lyondell Contributed
     Business and $2.0 to $2.4 billion for the Millennium Contributed Business.
 
     The preparation of a fairness opinion is not susceptible to partial
analysis or summary descriptions. Salomon believes that its analysis and the
summary set forth above must be considered as a whole and that selecting
portions of its analyses and the factors considered by it, without considering
all analyses and factors, could create an incomplete view of the processes
underlying the analysis set forth in its opinion and the Salomon Report. The
ranges of valuations resulting from any particular analysis described above
should not be taken to be the view of Salomon of the actual value of the
Lyondell Contributed Business or the Millennium Contributed Business.
 
     In performing its analyses, Salomon made numerous assumptions with respect
to industry performance, general business, financial, market and economic
conditions and other matters, many of which are beyond the control of Lyondell
or Millennium. The analyses which Salomon performed are not necessarily
indicative of actual values or actual future results, which may be significantly
more or less favorable than suggested by such analyses. Such analyses were
prepared solely as part of Salomon's analysis of the fairness, from a financial
point of view, of the Allocation. The analyses do not purport to
 
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be appraisals or to reflect the prices at which assets might actually be sold or
the prices at which any securities may trade at the present time or at any time
in the future.
 
     Salomon is not affiliated with Lyondell or Millennium. Salomon has
previously rendered certain financial advisory and investment banking services
to Lyondell and Millennium, for which Salomon received customary compensation.
In the ordinary course of its business, Salomon may actively trade the debt and
equity securities of Lyondell and Millennium for its own account and the
accounts of its customers and, accordingly, may at any time hold a long or short
position in such securities. Pursuant to an engagement letter dated June 26,
1997, Lyondell agreed to pay Salomon for its financial advisory and investment
banking services in connection with the Joint Venture Transaction (including
services related to Lyondell's strategic interest in Millennium that were
performed prior to the date of the letter) a cash fee of $7 million, which will
be payable upon consummation of the Joint Venture Transaction. Lyondell also
agreed to reimburse Salomon for certain out-of-pocket expenses incurred by
Salomon in connection with the Joint Venture Transaction. Lyondell also agreed
to indemnify Salomon and certain related persons against certain liabilities,
including liabilities under the Federal securities laws, relating to or arising
out of its engagement.
 
     Salomon is an internationally recognized investment banking firm that
provides financial services in connection with a wide range of business
transactions. As part of its business, Salomon regularly engages in the
valuation of companies and their securities in connection with mergers and
acquisitions, negotiated underwritings, competitive biddings, secondary
distributions of listed and unlisted securities, private placements and for
other purposes. Lyondell retained Salomon based on Salomon's expertise in the
valuation of companies as well as its familiarity with Lyondell and other
petrochemicals companies.
 
OPINION OF FINANCIAL ADVISOR TO MILLENNIUM
 
     Pursuant to an engagement letter dated July 1, 1997, Millennium retained
J.P. Morgan to deliver a fairness opinion in connection with the proposed Joint
Venture Transaction.
 
     At the meeting of the Board of Directors of Millennium on July 23, 1997,
J.P. Morgan rendered its written opinion to the Board of Directors of Millennium
that, as of such date and subject to the execution of the Master Transaction
Agreement on the terms then contemplated by Millennium, the consideration to be
received by Millennium in exchange for the Millennium Contributed Business
pursuant to the Master Transaction Agreement was fair from a financial point of
view to Millennium. No limitations were imposed by Millennium's Board of
Directors upon J.P. Morgan with respect to the investigations made or procedures
followed by it in rendering its opinions, other than the confidentiality
agreement described below.
 
     The full text of the written opinion of J.P. Morgan dated July 23, 1997,
which sets forth the assumptions made, matters considered and limits on the
review undertaken, is attached as Annex B to this Joint Proxy Statement and is
incorporated herein by reference. Millennium's stockholders are urged to read
the opinion in its entirety. J.P. Morgan's written opinion is addressed to the
Board of Directors of Millennium, is directed only to the consideration to be
received in the Joint Venture Transaction and does not constitute a
recommendation to any stockholder of Millennium as to how such stockholder
should vote at the Millennium Meeting. The summary of the opinion of J.P. Morgan
set forth in this Joint Proxy Statement is qualified in its entirety by
reference to the full text of such opinion.
 
     In arriving at its opinion, J.P. Morgan reviewed, among other things, a
draft of the proposed Master Transaction Agreement; the audited financial
statements of Millennium and Lyondell for the fiscal year ended December 31,
1996 and the unaudited financial statements of Millennium and Lyondell for the
period ended June 30, 1997 and, in the case of its opinion dated the date of
this Joint Proxy Statement, the audited financial statements of Millennium and
Lyondell for the fiscal year ended December 31, 1996; current and historical
market prices of Millennium's and Lyondell's Common Stock; certain publicly
available information concerning the business of Millennium and Lyondell and of
certain other companies engaged in businesses comparable to those of
Millennium's and Lyondell's proposed contributed assets as contemplated in the
Master Transaction Agreement, and the reported market prices for certain other
Millennium and Lyondell securities deemed comparable; asset replacement cost
estimates published by Chem Data Inc.; the terms of other business combinations
deemed relevant by J.P. Morgan; certain internal financial analyses and
forecasts prepared by Millennium and Lyondell and
 
                                       23
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<PAGE>
their respective managements; and certain agreements with respect to outstanding
indebtedness or obligations of Millennium and Lyondell. J.P. Morgan also held
discussions with certain members of the management of Millennium and Lyondell
with respect to certain aspects of the Joint Venture Transaction, and the past
and current business operations of Millennium and Lyondell. The financial
condition and future prospects and operations of Millennium and Lyondell and
certain other matters believed necessary or appropriate to J.P. Morgan's
inquiry. In addition, J.P. Morgan visited certain representative facilities of
Millennium and Lyondell, and reviewed such other financial studies and analyses
and considered such other information as it deemed appropriate for the purposes
of its opinion.
 
     In connection with its analysis of the Joint Venture Transaction and
rendering its opinion, J.P. Morgan was subject to an agreement with Lyondell
that prohibited J.P. Morgan from disclosing to Millennium, Millennium's Board or
management certain information, including financial forecasts, received by J.P.
Morgan from Lyondell and related to the Lyondell Contributed Business. The
purpose of this agreement, which was entered into at the request of Millennium
and with Millennium's approval, was to ensure that competitively sensitive
information about Lyondell would not be disclosed to Millennium if the Joint
Venture Transaction did not close.
 
     J.P. Morgan relied upon and assumed, without independent verification, the
accuracy and completeness of all information that was publicly available or that
was furnished to it by Millennium and Lyondell or otherwise reviewed by J.P.
Morgan, and J.P. Morgan has not assumed any responsibility or liability
therefor. J.P. Morgan has not conducted any valuation or appraisal of any assets
or liabilities, nor have any valuations or appraisals been provided to J.P.
Morgan. In relying on financial analyses and forecasts provided to J.P. Morgan,
J.P. Morgan has assumed that they have been reasonably prepared based on
assumptions reflecting the best currently available estimates and judgments by
management as to the expected future results of operations and financial
condition of Millennium and Lyondell. J.P. Morgan has also assumed that the
Joint Venture Transaction will have the tax consequences described in this Joint
Proxy Statement, and in discussions with, and materials furnished to J.P. Morgan
by, representatives of Millennium, and that the other transactions contemplated
by the Master Transaction Agreement will be consummated as described in the
Master Transaction Agreement and this Joint Proxy Statement.
 
     The projections furnished to J.P. Morgan for Millennium and Lyondell were
prepared by the respective managements of each company. Neither Millennium nor
Lyondell publicly discloses internal management projections of the type provided
to J.P. Morgan in connection with J.P. Morgan's analysis of the Joint Venture
Transaction, and such projections were not prepared with a view toward public
disclosure. These projections were based on numerous variables and assumptions
that are inherently uncertain and may be beyond the control of management,
including, without limitation, factors related to general economic and
competitive conditions and prevailing interest rates. Accordingly, actual
results could vary significantly from those set forth in such projections.
 
     J.P. Morgan's opinions are based on economic, market and other conditions
as in effect on, and the information made available to J.P. Morgan as of, the
date of such opinions. Subsequent developments may affect the written opinion
dated the date of this Joint Proxy Statement, and J.P. Morgan does not have any
obligation to update, revise or reaffirm such opinion. J.P. Morgan expressed no
opinion as to the price at which Millennium's Common Stock will trade at any
future time.
 
     In accordance with customary investment banking practice, J.P. Morgan
employed generally accepted valuation methods in reaching its opinion. The
following is a summary of the material financial analyses utilized by J.P.
Morgan in connection with providing its opinion.
 
     PUBLIC TRADING MULTIPLES. Using publicly available information, J.P. Morgan
compared selected financial data of Millennium and Lyondell with similar data
for selected publicly traded companies engaged in businesses which J.P. Morgan
judged to be analogous to the contributed assets of Millennium and Lyondell. The
companies selected by J.P Morgan were Dow Chemical, Arco Chemical, Lyondell,
Union Carbide and Geon. These companies were selected, among other reasons,
because their business operations, in aggregate, are similar to those of the
contributed assets of Millennium and Lyondell. Given the cyclical nature of the
petrochemicals industry, normalized multiples over the cycle (1990 to 1996) for
the above mentioned comparable companies were deemed to be appropriate. J.P.
 
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Morgan used the average projected (12 months forward) firm value/earnings before
interest and taxes and firm value/earnings before interest, taxes and
depreciation and amortization for its analysis. A range of 5.5x to 6.5x firm
value/earnings before interest, taxes and depreciation and amortization; and
7.0x to 8.5x firm value/earnings before interest and taxes were appropriate for
the average of the period analyzed. These multiples were applied to a matrix of
normalized earnings provided to J.P. Morgan by Millennium and Lyondell for their
respective contributed assets, yielding an implied stand alone trading value
range of between $2.3 billion and $3.0 billion for the Millennium Contributed
Business and between $2.3 billion and $3.1 billion for the Lyondell Contributed
Business. On a combined basis and giving consideration to the Partnership's
approximately $1.4 billion of net indebtedness, public trading comparable
multiples yielded a trading value range of between $2.4 billion and $2.95
billion for the sum of Millennium's 43% equity interest in the Partnership plus
the $1.0 billion in cash realized by Millennium from repayment of the $750
million of the Millennium Contributed Debt and the $250 million retention of
accounts receivable contemplated in the Joint Venture Transaction (the '$1.0
Billion Cash Realization').
 
     ESTIMATED REPLACEMENT COST ANALYSIS. In accordance with industry practice,
J.P. Morgan estimated the replacement cost of contributed assets of each party
as contemplated in the Master Transaction Agreement by using replacement cost
estimates published by Chem Data Inc., an industry consulting firm located in
Houston, Texas. Based upon the industry estimates prepared by Chem Data Inc.,
J.P. Morgan estimated the replacement cost value of the contributed assets of
each party and applied an appropriate depreciation multiplier to each asset
based on its competitive cost position relative to world scale replacement cost
estimates provided by Chem Data Inc. The appropriate depreciation multiplier was
determined by, among other things, conversations with Millennium and Lyondell
managements regarding the relative cost position of the contributed assets of
each company. The results of this analysis yielded an implied stand-alone
replacement cost value range of between $2.5 billion and $2.85 billion for
Millennium's contributed assets and between $2.4 billion and $2.7 billion for
Lyondell's contributed assets. On a combined basis, and giving consideration to
the Partnership's approximately $1.4 billion of net indebtedness, the
replacement cost analysis yielded a value range of between $2.5 billion and
$2.75 billion for the sum of Millennium's 43% equity interest in the Partnership
plus the $1.0 Billion Cash Realization.
 
     DISCOUNTED CASH FLOW ANALYSIS. J.P. Morgan conducted a discounted cash flow
analysis for the purpose of determining the firm value of the contributed assets
of Millennium and Lyondell. J.P. Morgan calculated the unlevered free cash flows
that the contributed assets of each of Millennium and Lyondell are expected to
generate during fiscal years 1998 through 2002 based upon financial projections
prepared by the managements of Millennium and Lyondell through the year ended
2002 and upon management projections adjusted by J.P. Morgan to reflect more
moderate growth in revenues and lower operating margins during the six-year
period. J.P. Morgan also calculated a range of terminal asset values of the
contributed assets of each of Millennium and Lyondell at the end of the 6-year
period ending 2002 by applying a firm value/earnings before interest, taxes, and
depreciation and amortization multiple of 5.5x to 6.5x to the average earnings
before taxes, interest and depreciation and amortization for the projected
period 1998 to 2002 for the contributed assets of each of Millennium and
Lyondell. The unlevered free cash flows and the range of terminal asset values
were then discounted to present values using a range of discount rates from 9.5%
to 10.5%, which were chosen by J.P. Morgan based upon an analysis of the
weighted average cost of capital of Millennium and Lyondell. Based on the
management projections and a discount rate of 10.0%, the discounted cash flow
analysis indicated a range of firm values of between $2.4 billion and $2.8
billion for Millennium's contributed assets and $2.35 billion and $2.7 billion
for Lyondell's contributed assets on a stand-alone basis (i.e., without
synergies). On a combined basis, not including synergies, and giving
consideration to the Partnership's approximately $1.4 billion of net
indebtedness and the $1.0 Billion Cash Realization, the discounted cash flow
analysis yielded a value range of between $2.45 billion and $2.75 billion for
the sum of Millennium's 43% equity interest in the Partnership plus the $1.0
Billion Cash Realization.
 
     In connection with its opinion dated the date of this Joint Proxy
Statement, J.P. Morgan reviewed the analyses used to render its July 23, 1997
written opinion to the Board of Directors of Millennium by performing procedures
to update certain of such analyses and by reviewing the assumptions upon which
such analyses were based and the factors considered in connection therewith.
 
                                       25
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     The summary set forth above does not purport to be a complete description
of the analyses or data presented by J.P. Morgan. The preparation of a fairness
opinion is a complex process and is not necessarily susceptible to partial
analysis or summary description. J.P. Morgan believes that the summary set forth
above and its analyses must be considered as a whole and that selecting portions
thereof, without considering all of its analyses, could create an incomplete
view of the processes underlying its analyses and opinion. J.P. Morgan based its
analyses on assumptions that it deemed reasonable, including assumptions
concerning general business and economic conditions and industry-specific
factors. The other principal assumptions upon which J.P. Morgan based its
analyses are set forth above under the description of each such analysis. J.P.
Morgan's analyses are not necessarily indicative of actual values or actual
future results that might be achieved, which values may be higher or lower than
those indicated. Moreover, J.P. Morgan's analyses are not and do not purport to
be appraisals or otherwise reflective of the prices at which businesses actually
could be bought or sold.
 
     As a part of its investment banking business, J.P. Morgan and its
affiliates are continually engaged in the valuation of businesses and their
securities in connection with mergers and acquisitions, investments for passive
and control purposes, negotiated underwritings, secondary distributions of
listed and unlisted securities, private placements, and valuations for estate,
corporate and other purposes. J.P. Morgan was selected to deliver an opinion to
Millennium's Board of Directors with respect to the Joint Venture Transaction on
the basis of such experience and on its familiarity with Millennium.
 
     For the delivery of its opinion, Millennium has agreed to pay J.P. Morgan a
fee of $500,000. In addition, Millennium has agreed to reimburse J.P. Morgan for
its expenses incurred in connection with its services, including the fees and
disbursements of counsel, and will indemnify J.P. Morgan against certain
liabilities, including liabilities arising under the Federal securities laws.
 
     J.P. Morgan and its affiliates maintain banking and other business
relationships with Millennium and its affiliates, for which it receives
customary fees. In the ordinary course of their businesses, affiliates of J.P.
Morgan may actively trade the debt and equity securities of Millennium or
Lyondell for their own accounts or for the accounts of customers and,
accordingly, they may at any time hold long or short positions in such
securities.
 
CERTAIN CONSEQUENCES OF THE JOINT VENTURE TRANSACTION
 
     After the Closing of the Joint Venture Transaction, both Lyondell and
Millennium will continue to exist in accordance with the current provisions of
their respective Certificates of Incorporation and bylaws, which will remain
unchanged by the Joint Venture Transaction. However, immediately following the
Joint Venture Transaction, Lyondell and Millennium will be engaged in the
contributed businesses only through their respective interests in the
Partnership. Immediately following the Joint Venture Transaction, Lyondell's
ownership interests in Lyondell Methanol Company, L.P., a Texas limited
partnership ('Lyondell Methanol'), and LYONDELL-CITGO Refining Company Ltd., a
Texas limited liability company ('LYONDELL-CITGO Refining'), will be the same as
prior to the Joint Venture Transaction. However, the Partnership will enter into
arrangements to provide (i) operating and other services for Lyondell Methanol
and (ii) marketing and other services for LYONDELL-CITGO Refining, which will be
on commercially reasonable terms. Immediately following the Joint Venture
Transaction, Millennium will continue to operate its TiO2, TiCl4,
cadmium/selenium pigments, silica gel and fragrances and flavors businesses, the
extent of which will not be affected by the Joint Venture Transaction.
Millennium will also retain its equity interest in Suburban Propane Partners,
L.P., and certain assets of its petrochemicals segment, including those used to
produce VAM, acetic acid, synthesis gas and methanol. In addition, the
Partnership and Millennium will negotiate a variety of operating, manufacturing
and technical services agreements related to the sites at which the business of
the Partnership will be conducted. See 'Certain Related Party Transactions.'
 
     After the Closing, the Partnership will be governed by the Partnership
Governance Committee with equal representation chosen by Lyondell and Millennium
(through Lyondell GP and Millennium GP, respectively). In general, the approval
of two or more Representatives acting for Lyondell GP will be necessary and
sufficient for the Partnership Governance Committee to take any action; however,
the Partnership Governance Committee may not take certain actions unless they
are approved by two members appointed by Lyondell GP and two members appointed
by Millennium GP. Each of Lyondell
 
                                       26
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and Millennium will be entitled to elect three of the six members of the
Partnership Governance Committee, and to appoint a co-chair of such Partnership
Governance Committee. See 'The Partnership Agreement -- Governance.'
 
INTEREST OF CERTAIN PERSONS IN THE JOINT VENTURE TRANSACTION
 
     In considering the recommendations of the Lyondell Board of Directors and
the Millennium Board of Directors, stockholders should be aware that certain
directors and executive officers of Lyondell and Millennium have certain
interests in the Joint Venture Transaction that are in addition to their
interests as stockholders of such companies generally. Certain directors and
members of the existing senior management of Lyondell and Millennium also will
be designated as executive officers of the Partnership. See 'Management of the
Partnership.'
 
     LYONDELL. Richard W. Park, Vice President, Human Resources of Lyondell and
Russell S. Young, Senior Vice President, Chief Financial Officer and Treasurer
of Lyondell have each entered into a Voluntary Separation Agreement and Release
('Separation Agreement') with Lyondell. Under the terms of these agreements,
each is expected to receive, upon completion of the Joint Venture Transaction,
severance payments equal to those payable under his existing severance agreement
upon a change of control of Lyondell. Such payments will be equivalent to three
times his current annual base salary and average Value Share Plan Award
(calculated as the average of the annual cash award paid for the previous three
year's performance cycles). Mr. Park is expected to receive an amount equal to
$           and Mr. Young will receive an amount equal to $           . Mr. Park
and Mr. Young are each eligible for accrued benefits under the Lyondell
Retirement Plan and the Lyondell Supplementary Executive Retirement Plan
('SERP'). In addition to the normal SERP benefits, each shall receive a special
supplementary benefit payment, and accordingly, the amount paid pursuant to the
SERP shall be enhanced by adding an additional five years of age and service to
the calculation and including a bonus in the calculation of annual salary. Any
unvested shares granted pursuant to the Lyondell Restricted Stock Plan and any
unvested options granted pursuant to the Lyondell Long-Term Incentive Plan shall
vest in 1998 and all associated cash payments that accompany the vesting of
restricted stock will also be made at that time. Each will continue to
participate in Lyondell's Executive Medical Plan, Lyondell's Long-Term
Disability Plan, and will continue to be covered under the terms of the
Executive Life Insurance Plan for a period of two years. They also are eligible
for full benefits under Lyondell's Financial Counseling Policy for 1998. The
Separation Agreements also provide that Messrs. Park and Young will receive
additional amounts to cover, on a 'grossed-up' basis, any federal income tax
payable with respect to Executive Deferral Plan payments. Lyondell estimates
that such amounts will be $      for Mr. Park and $      for Mr. Young.
 
     In addition, Lyondell has entered into new severance agreements with each
of its other executive officers. With the exception of one current executive
officer, the terms of the new severance agreements are substantially the same as
the existing agreements except that the 'gross-up' for federal income tax
payable with respect to payments related to the Executive Deferral Plan has been
eliminated. One executive officer of Lyondell, who has agreed to provide
services to the Partnership for a transitional period, will be entitled to
severance payments on terms substantially the same as those of Mr. Park and Mr.
Young upon termination of his employment with the Partnership. Lyondell will
assign to the Partnership the agreements with those individuals who will become
executive officers of the Partnership and will not be officers of Lyondell.
Lyondell will retain the agreements with the three executive officers who will
remain Lyondell executive officers (including Dan F. Smith). In addition,
pursuant to his severance agreement, Bob Gower, Lyondell's former Chairman of
the Board and Chief Executive Officer, will be entitled to receive an additional
payment equivalent to his 1996 base salary, or $714,000 as a result of the Joint
Venture Transaction.
 
     MILLENNIUM. The Closing of the Joint Venture Transaction will constitute a
Change in Control (as defined) under the July 1, 1996 change-in-control
agreement (the 'Change-in-Control Agreement') between Millennium Petrochemicals
and Dr. Ronald H. Yocum, the President of Millennium Petrochemicals. As a
result, Dr. Yocum will have the right under the Change-in-Control Agreement to
terminate his employment with Millennium Petrochemicals six months after the
Closing and receive: (i) three times his base salary; (ii) three times his
highest cash bonus paid or payable for any of the three
 
                                       27
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completed fiscal years prior to the Closing; (iii) three years of additional
service and compensation credit for pension purposes; (iv) three years of the
maximum contributions made by Millennium Petrochemicals under its qualified
defined contribution plan; and (v) provision for health coverage for Dr. Yocum
and his dependents for three years following the Closing. In order to ensure
that Dr. Yocum continues as an executive officer, Millennium has agreed to waive
the requirement that Dr. Yocum terminate his employment in order to receive such
benefits. Millennium estimates that Dr. Yocum will be entitled to receive
$          from Millennium Petrochemicals as a result of such provisions. In
addition, the 224,026 shares of Millennium Common Stock received by Dr. Yocum on
October 8, 1996 as restricted shares under Millennium's Long-Term Stock
Incentive Plan will vest upon the Closing. At the closing price of the
Millennium Common Stock on the New York Stock Exchange on             1997, such
shares have a value of $          . The Change-in-Control Agreement also
provides that Dr. Yocum will receive from Millennium Petrochemicals an
additional amount to cover, on a 'grossed-up' basis, any federal excise tax due
on the above-described amounts. Millennium estimates that such amount will be
approximately $          .
 
ACCOUNTING TREATMENT
 
     Consistent with the accounting policies of Lyondell and Millennium, both
Lyondell and Millennium will account for their general partner interests and
limited partner interests in the Partnership on an equity basis, effective as of
the Closing. This accounting treatment is reflected in the pro forma financial
statements of Lyondell and Millennium that are included in this Joint Proxy
Statement.
 
FEDERAL INCOME TAX CONSEQUENCES OF THE JOINT VENTURE TRANSACTION
 
     The Joint Venture Transaction will not have federal income tax consequences
for shareholders of either Lyondell or Millennium. Neither Lyondell nor
Millennium is expected to recognize gain or loss for federal income tax purposes
as a result of the Joint Venture Transactions.
 
NO APPRAISAL RIGHTS
 
     Under the DGCL, neither holders of Lyondell Common Stock nor holders of
Millennium Common Stock are entitled to appraisal or dissenters' rights in
connection with the Joint Venture Transaction.
 
CLOSING DATE
 
     The Closing is expected to take place promptly following the satisfaction
of all of the conditions set forth in the Master Transaction Agreement,
including, without limitation, receipt of the requisite affirmative votes of the
stockholders of Lyondell and Millennium. See 'The Master Transaction
Agreement -- Conditions to Closing.' Lyondell and Millennium anticipate that the
Closing will occur on or before January 1, 1998.
 
                                  THE PARTIES
 
     THE FOLLOWING INFORMATION RELATING TO LYONDELL AND MILLENNIUM IS QUALIFIED
IN ITS ENTIRETY BY THE DETAILED INFORMATION CONTAINED IN THE DOCUMENTS REFERRED
TO IN 'WHERE YOU CAN FIND MORE INFORMATION,' WHICH ARE INCORPORATED HEREIN BY
REFERENCE.
 
LYONDELL
 
     Lyondell is a leading low-cost petrochemicals and polymers producer.
Lyondell manufactures a wide variety of petrochemicals, including ethylene,
propylene, butadiene, aromatics and specialty products, and polymers, including
high density polyethylene ('HDPE'), low-density polyethylene ('LDPE') and
polypropylene. Lyondell's petrochemicals and polymers products are used
primarily in the manufacture of other chemicals and products, which in turn are
used in the production of a wide variety of consumer and industrial products.
Lyondell produces methanol through its interest in Lyondell Methanol. Through
its interest in LYONDELL-CITGO Refining, Lyondell produces refined petroleum
products, including gasoline, low-sulfur diesel, jet fuel, aromatics and
lubricants ('lube oils'). LYONDELL-CITGO Refining sells its principal refined
products primarily to CITGO Petroleum Corporation ('CITGO').
 
     Lyondell was formed in 1985 as a division of ARCO and became a publicly
traded company in January 1989.
 
     In February 1990, Lyondell acquired a polypropylene plant and a low-density
polyethylene plant located in Pasadena, Texas ('Bayport Facility').
 
     In July 1993, Lyondell contributed its refining business, including a
Houston, Texas refinery (the 'Refinery'), a lube oil blending and packaging
plant in Birmingport, Alabama and refining working
 
                                       28
 <PAGE>
<PAGE>
capital to LYONDELL-CITGO Refining. Lyondell retained a participation interest
in LYONDELL-CITGO Refining through its wholly-owned subsidiary, Lyondell
Refining Company. LYONDELL-CITGO Refining completed a major upgrade project at
the Refinery in the first quarter of 1997. Lyondell has an approximate 60%
interest in LYONDELL-CITGO Refining. CITGO holds the remaining approximate 40%
interest. As of January 1, 1997, Lyondell accounts for its investment in
LYONDELL-CITGO Refining under the equity method of accounting, meaning that the
operations of LYONDELL-CITGO Refining are no longer consolidated line by line
with those of Lyondell.
 
     In May 1995, Lyondell acquired Occidental Chemical Corporation's ALATHON
HDPE business ('ALATHON Business'). Assets involved in this acquisition included
resin production facilities in Matagorda, Texas (the 'Matagorda Facility') and
Victoria, Texas (the 'Victoria Facility'), related research and development
activities and the rights to the Alathon'r' trademark.
 
     In July 1996, Lyondell and Millennium announced the execution of a Letter
of Intent with two other olefins producers for the planned construction of a
worldscale olefins plant ('Joint Olefins Venture'). After the withdrawal of one
of the participants in October 1996, Lyondell, Millennium and the other partner
are continuing to evaluate options for the proposed plant including alternative
designs for utilizing various different feedstock mixes, as well as size,
schedule and participants.
 
     In December 1996, Lyondell announced the formation of Lyondell Methanol
with MCN Investment Corporation ('MCNIC'), a division of MCN Corporation, to own
Lyondell's 248 million gallons per year methanol plant. Under the terms of the
agreement, MCNIC purchased a 25% interest in the methanol business. Lyondell
retained a 75% interest and serves as managing partner and operator.
 
     Lyondell's principal executive offices are located at 1221 McKinney Street,
Houston, Texas 77010 and its telephone number is (713) 652-7200.
 
MILLENNIUM
     Millennium is a major international chemicals company, with leading market
positions in a broad range of commodity, industrial, performance and specialty
chemicals.
 
     Millennium has three principal operating subsidiaries: Millennium
Petrochemicals (formerly known as Quantum); Millennium Inorganic Chemicals Inc.
(collectively with its non-U.S. affiliates, 'Millennium Inorganic Chemicals'),
formerly known as SCM Chemicals Inc.; and Millennium Specialty Chemicals Inc.
('Millennium Specialty Chemicals'), formerly known as Glidco Inc. Millennium
changed the names of these three subsidiaries on March 3, 1997, to reflect their
shared value-creation principles and corporate identity. Through its
subsidiaries, Millennium is:
 
       - The largest producer of polyethylene products in the United States;
 
       - The second largest producer of TiO2 in the United States and the third
         largest producer of TiO2 in the world;
 
       - The second largest producer of acetic acid and vinyl acetate monomer in
         the United States;
 
       - A leading producer of high value-added performance polymers and of
         TiCl4, cadmium/selenium pigments and silica gel; and
 
       - A leading producer of fragrances and flavors chemicals derived from
         crude sulfate turpentine.
 
     In addition, an indirect subsidiary of Millennium serves as the general
partner of Suburban Propane Partners, L.P. ('Suburban Propane'), a
publicly-traded limited partnership which, through an operating partnership, is
the third largest retail marketer of propane in the United States. Millennium
owns a 2% general partnership interest and an approximate 24% subordinated
limited partnership interest, each on a combined basis, in these partnerships.
Millennium accounts for its 26.4% interest in Suburban Propane as an equity
investment.
 
     Millennium was incorporated in Delaware on April 18, 1996. It has been an
independent, publicly-owned company since its Demerger on October 1, 1996 from
Hanson. In connection with the Demerger, Millennium acquired its present
businesses from Hanson and issued to Hanson's shareholders all of Millennium's
then outstanding Common Stock.
 
     Millennium's United Kingdom office is located at Laporte Road,
Stallingborough, Nr. Grimsby, North East Lincolnshire, DN40 2PR, England. Its
United Kingdom telephone number is 0345 662663. Millennium's principal executive
offices in the United States are located at 99 Wood Avenue South, Iselin, New
Jersey 08830. Its United States telephone number is (732) 603-6600.
 
                                       29
<PAGE>
<PAGE>
                  SELECTED HISTORICAL AND UNAUDITED PRO FORMA
                          FINANCIAL DATA OF LYONDELL,
                         MILLENNIUM AND THE PARTNERSHIP
 
INTRODUCTION
 
     Set forth below is selected historical financial data of each of Lyondell
and Millennium and its respective Contributed Business, together with unaudited
pro forma financial data of each of Lyondell and Millennium giving effect to the
Joint Venture Transaction.
 
     Also set forth below is unaudited pro forma financial data of the
Partnership.
 
SELECTED HISTORICAL FINANCIAL DATA
 
     The selected historical financial data set forth below are derived, in
part, from the audited financial statements of each of Lyondell and Millennium
incorporated herein by reference and the audited financial statements of each of
the Contributed Businesses included in this Joint Proxy Statement. The selected
historical financial data as of and for the periods ended June 30, 1997 and 1996
for Lyondell and as of and for the periods ended June 30, 1997 and 1996 and
December 31, 1993 and 1992 for the Lyondell Contributed Business are derived
from their unaudited financial statements. The selected historical financial
data as of and for the periods ended June 30, 1997 and 1996 and September 30,
1992 for Millennium and as of and for the periods ended June 30, 1997 and 1996
and December 31, 1993 and 1992 for the Millennium Contributed Business are
derived from their unaudited financial statements.
 
     In the opinion of each of Lyondell's and Millennium's management, the
unaudited financial data of each company, respectively, have been prepared on a
basis consistent with that of the audited financial data and the interim
financial data include all adjustments (which consist only of normal recurring
adjustments) necessary for a fair presentation of interim results. Selected
historical financial data for the Contributed Businesses may not be indicative
of their future performance when operated by the Partnership. Furthermore, the
selected historical financial data presented below do not reflect certain pro
forma adjustments giving effect to the Joint Venture Transactions. The selected
historical financial data should be read in conjunction with the 'Management's
Discussion and Analysis of Financial Condition and Results of Operations' and
the financial statements and notes thereto of each of Lyondell and Millennium
incorporated by reference in this Joint Proxy Statement and the financial
statements and notes thereto of each of the Contributed Businesses included in
this Joint Proxy Statement. See 'Index to Financial Statements.' Historical
earnings per share and dividend data have not been presented for the Contributed
Businesses because there is no separate identifiable pool of capital for the
relevant periods upon which a per share calculation could be based.
 
UNAUDITED PRO FORMA FINANCIAL DATA
 
     The unaudited pro forma financial data set forth below reflect the Joint
Venture Transaction as if it had been completed as of June 30, 1997 for pro
forma balance sheet data purposes and as of January 1, 1997 and January 1, 1996,
respectively, for pro forma income statement data purposes. The assets and
liabilities of the Contributed Businesses are reflected at their historical net
book value in the unaudited pro forma balance sheet of the Partnership.
 
     The unaudited pro forma financial data do not necessarily reflect the
results of operations or financial position of Lyondell, Millennium or the
Partnership that would have resulted had such transactions actually been
consummated as of such dates. Also, these data are not necessarily indicative of
the future results of operations or future financial position of Lyondell,
Millennium or the Partnership. The pro forma statements of income of the
Partnership do not reflect any Synergies expected to arise out of the
combination of the Contributed Businesses other than anticipated reduced
interest rates on new Partnership debt. The impact of the Synergies, assuming
their full realization, is discussed under 'The Proposed Joint
Venture -- Reasons for the Joint Venture Transaction.'
 
                                       30
 <PAGE>
<PAGE>
SELECTED HISTORICAL AND UNAUDITED PRO FORMA FINANCIAL DATA OF LYONDELL
 
                         LYONDELL PETROCHEMICAL COMPANY
                       SELECTED HISTORICAL FINANCIAL DATA
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                     SIX MONTHS ENDED JUNE 30                     YEAR ENDED DECEMBER 31,
                                     ------------------------   ------------------------------------------------------------
                                              RECLASSIFIED(a)   RECLASSIFIED(a)
                                      1997         1996              1996          1996     1995     1994     1993     1992
                                     ------   ---------------   ---------------   ------   ------   ------   ------   ------
                                           (UNAUDITED)          (UNAUDITED)
<S>                                  <C>      <C>               <C>               <C>      <C>      <C>      <C>      <C>
Income statement data:
     Net sales.....................  $1,544       $ 1,192           $ 2,644       $5,052   $4,936   $3,857   $3,850   $4,809
     Operating income..............     225            68               274          278      706      424       93      104
     Net income....................     133            39               126          126      389      223       26       16
Balance sheet data (at period end):
     Property, plant and
       equipment...................     883           907               893        2,270    1,814      880      655      623
     Total assets..................   1,909         1,783             1,890        3,276    2,606    1,663    1,231    1,215
     Long term debt................     743           744               744        1,194      807      707      717      725
     Total liabilities.............   1,381         1,401             1,459        2,845    2,226    1,600    1,319    1,221
     Stockholders' equity
       (deficit)...................     528           382               431          431      380       63      (88)      (6)
Other data:
     Depreciation and
       amortization................      44            33                74          110       86       65       58       39
     Capital expenditures(b).......      28            42                80          609      982      252       69       97
</TABLE>
 
- ------------
 (a) The unaudited reclassified financial information presents the financial
     position and results of operations of Lyondell as of and for the periods
     ended December 31, 1996 and June 30, 1996 using the equity method of
     accounting (rather than consolidation) for Lyondell's investment in
     LYONDELL-CITGO Refining as if the change in accounting method had been
     effective on January 1, 1996 rather than on January 1, 1997.
 (b) Includes $473, $458 and $135 in 1996, 1995 and 1994, respectively, for the
     upgrade project at LYONDELL-CITGO Refining primarily funded by CITGO
     Petroleum Corporation and non-recourse debt. Also includes $356 in 1995 for
     the acquisition of the Alathon'r' high-density polyethylene business.
 
                                       31
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                       SELECTED HISTORICAL FINANCIAL DATA
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                        SIX MONTHS ENDED
                                                            JUNE 30,                  YEAR ENDED DECEMBER 31,
                                                       -------------------   ------------------------------------------
                                                         1997       1996      1996     1995     1994     1993     1992
                                                       --------   --------   ------   ------   ------   ------   ------
                                                           (UNAUDITED)                                    (UNAUDITED)
 
<S>                                                    <C>        <C>        <C>      <C>      <C>      <C>      <C>
Income statement data:
     Net sales.......................................   $1,449     $1,134    $2,515   $2,509   $1,806   $1,137   $1,555
     Operating income (loss).........................      194         65       223      515      288      (32)      36
     Net income (loss)...............................      101         19       102      277      137      (25)     (22)
Balance sheet data (at period end):
     Property, plant and equipment...................      834        831       840      818      381      366      386
     Total assets....................................    1,504      1,420     1,494    1,306      834      626      626
     Long term debt..................................      743        745       745      595      707      717      507
     Total liabilities...............................      987      1,007     1,071      986      921      887      640
     Invested capital................................      517        413       423      320      (87)    (261)     (14)
Other data:
     Depreciation and amortization...................       41         29        67       46       35       35       24
     Capital expenditures(a).........................       28         42        80      476       40       14       43
</TABLE>
 
- ------------
 
 (a) Includes $356 in 1995 for the acquisition of the Alathon'r' high-density
     polyethylene business.
 
                                       32
 <PAGE>
<PAGE>
                         LYONDELL PETROCHEMICAL COMPANY
                 UNAUDITED PRO FORMA CONSOLIDATED BALANCE SHEET
                                 JUNE 30, 1997
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                               LESS
                                                                            CONTRIBUTED   INVESTMENT IN                       PRO
                                                                ACTUAL(a)    BUSINESS      PARTNERSHIP       ADJUSTMENTS     FORMA
                                                                ---------   -----------   -------------      -----------   ---------
<S>                                                             <C>         <C>           <C>                <C>           <C>
                            ASSETS
Current assets:
     Cash and cash equivalents................................   $    30                                                    $    30
     Trade receivables, net...................................       350      $  (350)                                        --
     Inventories..............................................       206         (206)                                        --
     Other current assets.....................................        14          (12)                                            2
                                                                ---------   -----------                                    ---------
          Total current assets................................       600         (568)                                           32
Property, plant and equipment -- net..........................       834         (834)                                        --
Other non-current assets:
     Investments, note receivable and other assets............       465         (102)                                          363
                                                                                             $   495(b)         $   7(c)
     Investment in Partnership................................     --                            345(d)           200(e)      1,047
                                                                ---------   -----------   -------------      -----------   ---------
          Total assets........................................   $ 1,899      $(1,504)       $   840            $ 207       $ 1,442
                                                                ---------   -----------   -------------      -----------   ---------
                                                                ---------   -----------   -------------      -----------   ---------
             LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
     Notes payable............................................   $   150                                                    $   150
     Current maturities of long term debt.....................         2      $    (2)(f)                                     --
     Trade accounts payable...................................       154         (154)                          $ 154(e)        154
     Income taxes payable.....................................        12                                                         12
                                                                                                                   46(e)
     Accrued expenses and other liabilities...................        67          (52)                             12(c)         73
                                                                ---------   -----------                      -----------   ---------
          Total current liabilities...........................       385         (208)                            212           389
Non-current liabilities:
     Long term debt...........................................       743         (743)(f)                                     --
     Note payable to Partnership..............................     --                        $   345(d)                         345
     Deferred income taxes....................................       170                          (8)(b)           (2)(c)       160
     Other liabilities........................................        73          (36)                                           37
                                                                ---------   -----------   -------------      -----------   ---------
          Total liabilities...................................     1,371         (987)           337              210           931
                                                                ---------   -----------   -------------      -----------   ---------
Stockholders' equity:
     Preferred stock (par value $.01 per share, authorized
       80,000,000 shares; none issued and outstanding)........     --                                                         --
     Common stock (par value $1 per share, authorized
       250,000,000 shares; issued and outstanding 80,000,000
       shares)................................................        80                                                         80
     Paid in capital..........................................       158                                                        158
     Retained earnings........................................       290                         (14)(b)           (3)(c)       273
     Invested capital.........................................     --            (517)           517(b)                       --
                                                                ---------   -----------   -------------      -----------   ---------
          Total stockholders' equity..........................       528         (517)           503               (3)          511
                                                                ---------   -----------   -------------      -----------   ---------
Total liabilities and stockholders' equity....................   $ 1,899      $(1,504)       $   840            $ 207       $ 1,442
                                                                ---------   -----------   -------------      -----------   ---------
                                                                ---------   -----------   -------------      -----------   ---------
</TABLE>
 
- ------------
 (a) Commencing January 1, 1998, Lyondell will account for its investment in
     Lyondell Methanol using the equity method of accounting rather than
     consolidation. The financial position of Lyondell as of June 30, 1997 has
     been presented on an adjusted basis as if the change in accounting method
     had been effective January 1, 1997.
 (b) To reflect Lyondell's investment in the Partnership, representing the
     historical net book value of the contributed assets and liabilities reduced
     by Lyondell's 57% of severance and relocation costs to be paid by the
     Partnership and related tax effect.
 (c) To record the accrual of transaction costs ($7) and severance costs ($5),
     including the related tax effect ($2), relating to the formation of the
     Partnership to be borne by Lyondell.
 (d) To record the $345 note payable to and corresponding additional investment
     in the Partnership.
 (e) To reflect accounts payable and certain accrued liabilities which will not
     be contributed to the Partnership.
 (f) Although the Partnership will assume primary liability for such debt from
     Lyondell, Lyondell will remain liable to the holders of such debt.
 
                                       33
 <PAGE>
<PAGE>
                         LYONDELL PETROCHEMICAL COMPANY
             UNAUDITED PRO FORMA CONSOLIDATED STATEMENTS OF INCOME
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                       SIX MONTHS ENDED JUNE 30, 1997
                                                      -----------------------------------------------------------------
                                                                      LESS
                                                                   CONTRIBUTED    INVESTMENT IN                    PRO
                                                      ACTUAL(a)     BUSINESS       PARTNERSHIP     ADJUSTMENTS    FORMA
                                                      ---------    -----------    -------------    -----------    -----
<S>                                                   <C>          <C>            <C>              <C>            <C>
Sales and other operating revenues.................    $ 1,449       $(1,449)                                     $--
Equity investment income:
     Partnership...................................      --                           $ 182(b)                     182
     Refining business.............................         27                                                      27
     Methanol business.............................         38                                                      38
                                                      ---------                      ------                       -----
                                                            65                          182                        247

Cost of goods sold.................................      1,134        (1,134)                                      --
Depreciation and amortization......................         41           (41)                                      --
Selling, general and administrative expenses.......         95           (80)                                       15
                                                      ---------    -----------       ------                       -----
     Operating income..............................        244          (194)           182                        232

Interest expense...................................        (41)           35                          $ (11)(c)    (17)
Interest income....................................          6                                                       6
                                                      ---------    -----------       ------           -----       -----
Income before provision for income taxes...........        209          (159)           182             (11)       221
Provision for income taxes.........................         76           (58)            66(d)           (4)(d)     80
                                                      ---------    -----------       ------           -----       -----
Net income.........................................    $   133       $  (101)         $ 116           $  (7)      $141
                                                      ---------    -----------       ------           -----       -----
                                                      ---------    -----------       ------           -----       -----
Net income per share (80,000,000 shares
  outstanding).....................................    $  1.66                                                    $1.76
                                                      ---------                                                   -----
                                                      ---------                                                   -----
</TABLE>
 
<TABLE>
<CAPTION>
                                                                     YEAR ENDED DECEMBER 31, 1996
                                                 ---------------------------------------------------------------------
                                                                 LESS
                                                              CONTRIBUTED    INVESTMENT IN                        PRO
                                                 ACTUAL(A)     BUSINESS       PARTNERSHIP       ADJUSTMENTS      FORMA
                                                 ---------    -----------    -------------      -----------      -----
<S>                                              <C>          <C>            <C>                <C>              <C>
Sales and other operating revenues............    $ 2,515       $(2,515)                                         $--
Gain on sale of assets........................         30                                                          30
Equity investment income:
     Partnership..............................      --                           $ 242(b)                         242
     Refining business........................          2                                                           2
     Methanol business........................         35                                                          35
                                                 ---------                      ------                           -----
                                                       37                          242                            279

Cost of goods sold............................      2,068        (2,068)                                          --
Depreciation and amortization.................         67           (67)                                          --
Selling, general and administrative
  expenses....................................        173          (157)                                           16
                                                 ---------    -----------       ------                           -----
Operating income..............................        274          (223)           242                            293

Interest expense..............................        (79)           65                            $ (21)(c)      (35)
Interest income...............................          1                                                           1
                                                 ---------    -----------       ------             -----         -----
Income before provision for income taxes......        196          (158)           242               (21)         259
Provision for income taxes....................         70           (56)            86(d)             (8)(d)       92
                                                 ---------    -----------       ------             -----         -----
Net income....................................    $   126       $  (102)         $ 156             $ (13)        $167
                                                 ---------    -----------       ------             -----         -----
                                                 ---------    -----------       ------             -----         -----
Net income per share (80,000,000 shares
  outstanding)................................    $  1.58                                                        $2.09
                                                 ---------                                                       -----
                                                 ---------                                                       -----
</TABLE>
 
                                                   (See notes on following page)
 
                                       34
 <PAGE>
<PAGE>
Notes to Unaudited Pro Forma Consolidated Statements of Income:
 
     (a) Commencing January 1, 1998, Lyondell will account for its investment in
         Lyondell Methanol using the equity method of accounting rather than
         consolidation. Actual 1997 and 1996 results have been adjusted to
         present the results of operations of Lyondell using the equity method
         of accounting for Lyondell's investment in Lyondell Methanol as if the
         method of accounting had been effective January 1, 1996.
 
     (b) To reflect the sum of Lyondell's 57% share of the pro forma Partnership
         net income for the period and the amortization of the difference
         between the carrying value of Lyondell's investment and Lyondell's
         underlying equity in the Partnership ($168 and $14, respectively, for
         the 1997 period and $214 and $28, respectively, for the 1996 period.)
 
     (c) To record interest expense on the $345 note payable to the Partnership
         at an assumed annual interest rate of 6.2% for the 1996 period and 6.0%
         for the 1997 period.
 
     (d) To record the tax effect of adjustments (b) and (c) above at 36.4% for
         the 1997 period and 35.7% for the 1996 period.
 
                                       35
 <PAGE>
<PAGE>
SELECTED HISTORICAL AND UNAUDITED PRO FORMA FINANCIAL DATA OF MILLENNIUM
 
                           MILLENNIUM CHEMICALS INC.
                       SELECTED HISTORICAL FINANCIAL DATA
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                               SIX MONTHS ENDED      YEARS ENDED      THREE MONTHS        FISCAL YEARS ENDED
                                                   JUNE 30,         DECEMBER 31,         ENDED               SEPTEMBER 30,
                                               ----------------   -----------------   DECEMBER 31,   ------------------------------
                                                1997     1996      1996      1995         1994        1994     1993        1992
                                               ------   -------   -------   -------   ------------   ------   -------   -----------
                                                 (UNAUDITED)                                                            (UNAUDITED)
<S>                                            <C>      <C>       <C>       <C>       <C>            <C>      <C>       <C>
Income statement data:
     Net sales................................ $1,607   $ 1,510   $ 3,040   $ 3,800     $    908     $3,288   $   862     $   920
     Operating income(a)......................    198       115       283       842          203        344       139         181
     Income from continuing
       operations(a)(b).......................    102        93       141       331           84         66       103         138
     Net income (loss)(a)(b)(c)...............    102    (3,111)   (2,701)      349           96         94       123         194
Balance sheet data (at period end):
     Property, plant and equipment............  2,015     1,925     2,031     2,262        2,153      2,179     2,264         419
     Total assets.............................  5,065     6,140     5,601    10,043       10,024      9,691    10,135       5,182
     Long term debt...........................  1,787     3,311     2,360     3,304        3,274      2,289     2,704          32
     Total liabilities........................  3,669     5,513     4,283     5,242        5,166      5,053     4,692         663
     Stockholders'
       equity/invested capital(d).............  1,396       627     1,318     4,801        4,858      4,638     5,443       4,519
Other data (with respect to continuing
  operations):
     Depreciation and amortization............    106       102       201       241           59        247        44          38
     Capital expenditures.....................     74       153       285       276           30        109        28          43
</TABLE>
 
- ------------
 
 (a) The June 30, 1996 and December 31, 1996 amounts include the effects of
     non-recurring charges of $60 ($39 after tax) and $75 ($48 after-tax),
     respectively, to reduce the carrying value of certain facilities employed
     in the sulfate-process manufacturing of TiO2 and provide for the costs
     associated with the closure of certain of these facilities.
 
 (b) These 1996 amounts include a gain of $210 ($86 after-tax) resulting from
     the sale in March 1996 of a 73.6% equity interest in Suburban Propane. In
     1995 and fiscal 1994, Suburban Propane is included as a continuing
     operation.
 
 (c) These 1996 amounts include the effects of a non-cash after-tax charge of
     $3,206 relating to discontinued operations as a result of the adoption of
     the long-lived asset carrying value methodology provided by Statement of
     Financial Accounting Standards No. 121 ('SFAS 121'). The discontinued
     operations were sold to Hanson on October 6, 1996, in connection with the
     Demerger.
 
 (d) Includes net assets of the discontinued operations: $597 at June 30, 1996
     after giving effect to the adoption of SFAS 121; $3,772 at December 31,
     1995; $3,757 at December 31, 1994; $3,757 at September 30, 1994; $3,935 at
     September 30, 1993; and $3,818 at September 30, 1992.
 
                                       36
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                       SELECTED HISTORICAL FINANCIAL DATA
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                SIX MONTHS ENDED
                                                    JUNE 30,                   YEARS ENDED DECEMBER 31,
                                                ----------------    ----------------------------------------------
                                                 1997      1996      1996      1995      1994     1993(a)   1992(a)
                                                ------    ------    ------    ------    ------    ------    ------
                                                  (UNAUDITED)                                       (UNAUDITED)
<S>                                             <C>       <C>       <C>       <C>       <C>       <C>       <C>
Income statement data:
     Net sales...............................   $1,011    $  885    $1,860    $1,932    $1,645    $1,399    $1,491
     Operating income (loss).................      149        87       248       495       210       (33)       25
     Net income (loss).......................       61        21        92       243        68       (24)       16
Balance sheet data (at period end):
     Property, plant and equipment...........    1,305     1,331     1,335     1,237     1,224     1,283     1,311
     Total assets............................    3,027     3,055     3,121     2,977     2,978     3,046     1,797
     Long term debt..........................    1,004     1,009     1,009     1,013     1,016     1,020     1,024
     Total liabilities.......................    1,219     1,270     1,286     1,285     1,345     1,397     1,136
     Invested capital........................    1,808     1,785     1,835     1,692     1,633     1,649       661
Other data:
     Depreciation and amortization...........       66        61       122       125       129       138       133
     Capital expenditures....................       20       139       189       107        38        83        75
</TABLE>
 
- ------------
 
 (a) The periods ended prior to September 30, 1993 reflect the results of
     operations, assets and liabilities of the Contributed Business on Quantum's
     historical basis (prior to its acquisition by Hanson).
 
                                       37
 <PAGE>
<PAGE>
                           MILLENNIUM CHEMICALS INC.
                 UNAUDITED PRO FORMA CONSOLIDATED BALANCE SHEET
                                 JUNE 30, 1997
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                      LESS
                                                                   CONTRIBUTED   INVESTMENT IN                    PRO
                                                         ACTUAL     BUSINESS      PARTNERSHIP    ADJUSTMENTS     FORMA
                                                         ------    -----------   -------------   -----------     ------
<S>                                                      <C>       <C>           <C>             <C>             <C>
                        ASSETS
Current assets:
     Cash and cash equivalents.........................  $   26                                                  $   26
                                                                                                   $   285(a)
     Trade receivables, net............................     500      $  (285)                         (285)(b)      215
     Inventories.......................................     444         (239)                                       205
     Other current assets..............................      57          (16)                                        41
                                                         ------    -----------                   -----------     ------
          Total current assets.........................   1,027         (540)                       --              487
Property, plant and equipment -- net...................   2,015       (1,305)                                       710
Other non-current assets:
                                                                                                       (35)(a)
                                                                                                        35(b)
     Investment in Partnership.........................                             $ 1,792(d)         133(h)     1,925
     Other assets......................................     281          (27)                                       254
     Goodwill..........................................   1,742       (1,155)                                       587
                                                         ------    -----------   -------------   -----------     ------
          Total assets.................................  $5,065      $(3,027)       $ 1,792        $   133       $3,963
                                                         ------    -----------   -------------   -----------     ------
                                                         ------    -----------   -------------   -----------     ------
         LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
     Notes payable.....................................  $   82                                                  $   82
     Current maturities of long term debt..............       6      $    (2)                                         4
     Trade accounts payable............................     153          (64)                      $    64(h)       153
     Income taxes payable..............................     113                                                     113
                                                                                                        69(h)
     Accrued expenses and other liabilities............     367         (106)                           17(c)       347
                                                         ------    -----------                   -----------     ------
          Total current liabilities....................     721         (172)                          150          699
Non-current liabilities:
     Long term debt....................................   1,787           (2)                       (1,000)(b)(e)   785
                                                                                                       750(f)
     Millennium Contributed Debt.......................    --         (1,000)                          250(a)      --
     Deferred income taxes.............................     131                     $    (7)(d)         (7)(c)      117
     Other liabilities.................................   1,030          (45)                                       985
                                                         ------    -----------   -------------   -----------     ------
          Total liabilities............................   3,669       (1,219)            (7)           143        2,586
                                                         ------    -----------   -------------   -----------     ------
Stockholders' equity:
     Preferred stock (par value $.01 per share,
       authorized 25,000,000 shares; none issued and
       outstanding)....................................    --                                                      --
     Common stock (par value $.01 per share, authorized
       225,000,000 shares; issued and outstanding
       77,324,605 shares)..............................       1                                                       1
     Paid in capital...................................   1,334                                                   1,334
     Retained earnings.................................     117                          (9)(d)        (24)(c)(g)    84
     Unearned restricted stock.........................     (59)                                        14(g)       (45)
     Cumulative translation adjustment.................       3                                                       3
     Invested capital..................................    --         (1,808)         1,808(d)                     --
                                                         ------    -----------   -------------   -----------     ------
          Total stockholders' equity...................   1,396       (1,808)         1,799            (10)       1,377
                                                         ------    -----------   -------------   -----------     ------
Total liabilities and stockholders' equity.............  $5,065      $(3,027)       $ 1,792        $   133       $3,963
                                                         ------    -----------   -------------   -----------     ------
                                                         ------    -----------   -------------   -----------     ------
</TABLE>
 
                                                   (See notes on following page)
 
                                       38
 <PAGE>
<PAGE>
Notes to Unaudited Pro Forma Consolidated Balance Sheet:
 
(a) To reflect accounts receivable and $250 of indebtedness of the Millennium
    Contributed Business to Millennium, neither of which will be contributed to
    the Partnership.
 
(b) To reflect the application of Millennium's collection of $285 of accounts
    receivable to reduce bank debt ($250) and make a capital contribution to the
    Partnership ($35).
 
(c) To record accrual of transaction and severance costs, including the related
    tax effect, relating to the formation of the Partnership to be borne by
    Millennium.
 
(d) To reflect Millennium's investment in the Partnership, representing the
    historical net book value of the contributed assets and liabilities reduced
    by Millennium's 43% of severance and relocation costs to be paid by the
    Partnership and related tax effect.
 
(e) To reflect Millennium's repayment of bank debt using the proceeds of the
    Partnership's repayment of the Millennium Contributed Debt described in note
    (f) below.
 
(f) To reflect the Partnership's repayment of the Millennium Contributed Debt of
    $750 (which will be assumed by the Partnership), using proceeds of the New
    Credit Facility. Millennium America Inc. will guarantee $750 of the
    Partnership's indebtedness under the New Credit Facility. See 'Financing
    Arrangements for the Partnership.'
 
(g) To reflect vesting of restricted stock held by certain Millennium
    Petrochemical employees under provisions of the respective incentive plans.
 
(h) To reflect accounts payable and certain accrued liabilities which will not
    be contributed to the Partnership.
 
                                       39
 <PAGE>
<PAGE>
                           MILLENNIUM CHEMICALS INC.
             UNAUDITED PRO FORMA CONSOLIDATED STATEMENTS OF INCOME
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                  SIX MONTHS ENDED JUNE 30, 1997
                                               ---------------------------------------------------------------------
                                                            LESS
                                                         CONTRIBUTED    INVESTMENT IN                          PRO
                                               ACTUAL     BUSINESS       PARTNERSHIP     ADJUSTMENTS          FORMA
                                               ------    -----------    -------------    -----------          ------
<S>                                            <C>       <C>            <C>              <C>                  <C>
Net sales...................................   $1,607      $(1,011)                                            $ 596
Cost of goods sold..........................    1,195         (743)                                              452
Depreciation and amortization...............      106          (66)                                               40
Selling, development and administrative
  expenses..................................      108          (53)                                               55
                                               ------    -----------                                          ------
     Operating income.......................      198         (149)                                               49
                                                                                            $ (40)(a)
Interest expense............................      (70)          40                             33(b)             (37)
Interest income.............................        6                                                              6
Equity earnings of Partnership..............     --                         $ 114(c)                             114
Other income, net...........................       44                                                             44
                                               ------    -----------       ------           -----             ------
Income from continuing operations before
  provision for income taxes................      178         (109)           114              (7)               176
Provision for income taxes..................       76          (48)            50(d)           (3)(d)             75
                                               ------    -----------       ------           -----             ------
Income from continuing operations...........   $  102      $   (61)         $  64           $  (4)              $101
                                               ------    -----------       ------           -----             ------
                                               ------    -----------       ------           -----             ------
     Income per share from continuing
       operations (76,477,055 shares
       outstanding).........................   $ 1.33                                                          $1.32
                                               ------                                                         ------
                                               ------                                                         ------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                    YEAR ENDED DECEMBER 31, 1996
                                                 -------------------------------------------------------------------
                                                              LESS
                                                           CONTRIBUTED    INVESTMENT IN                        PRO
                                                 ACTUAL     BUSINESS       PARTNERSHIP     ADJUSTMENTS        FORMA
                                                 ------    -----------    -------------    -----------        ------
<S>                                              <C>       <C>            <C>              <C>                <C>
Net sales.....................................   $3,040      $(1,860)                                         $1,180
Cost of goods sold............................    2,264       (1,381)                                            883
Depreciation and amortization.................      201         (122)                                             79
Selling, development and administrative
  expenses....................................      217         (109)                                            108
Impairment of assets and related costs........       75                                                           75
                                                 ------    -----------                                        ------
     Operating income.........................      283         (248)                                             35
                                                                                              $ (80)(a)
Interest expense..............................     (214)          80                             68(b)          (146)
Interest income...............................       37                                                           37
Equity earnings of Partnership................     --                         $ 138(c)                           138
Gain on sale of Suburban Propane..............      210                                                          210
Other income, net.............................       14                                                           14
                                                 ------    -----------       ------           -----           ------
Income from continuing operations before
  provision for income taxes..................      330         (168)           138             (12)             288
Provision for income taxes....................      189          (76)            62(d)           (2)(d)          173
                                                 ------    -----------       ------           -----           ------
Income from continuing operations.............   $  141      $   (92)         $  76           $ (10)          $  115
                                                 ------    -----------       ------           -----           ------
                                                 ------    -----------       ------           -----           ------
Income per share from continuing operations
  (76,477,055 shares outstanding).............   $ 1.84                                                       $ 1.50
                                                 ------                                                       ------
                                                 ------                                                       ------
</TABLE>
 
- ------------
(a) To eliminate interest income on the Millennium Contributed Debt of $1,000 at
    8% per annum.
 
(b) To reduce interest expense due to repayment of bank debt using proceeds from
    the Partnership's repayment of the Millennium Contributed Debt and the
    collection of accounts receivable not contributed to the Partnership (an
    aggregate of $1,000 at 6.6% per annum for the 1997 period and 6.8% per annum
    for the 1996 period).
 
(c) To reflect the sum of Millennium's 43% share of the pro forma Partnership
    net income for the period and the amortization of the difference between the
    carrying value of Millennium's investment and Millennium's underlying equity
    in the Partnership ($126 and ($12), respectively, for the 1997 period and
    $162 and ($24), respectively, for the 1996 period).
 
(d) To reflect the tax effect of (a) and (b) above at 42.7% for the 1997 period
    and 59.8% for the 1996 period.
 
                                       40
<PAGE>
<PAGE>
UNAUDITED PRO FORMA FINANCIAL DATA OF THE PARTNERSHIP
 
                                THE PARTNERSHIP
                       UNAUDITED PRO FORMA BALANCE SHEET
                                 JUNE 30, 1997
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                        CONTRIBUTED
                                                                        BUSINESSES
                                                                   ---------------------    COMBINED                        PRO
                                                                   LYONDELL   MILLENNIUM   BUSINESSES   ADJUSTMENTS        FORMA
                                                                   --------   ----------   ----------   -----------        ------
<S>                                                                <C>        <C>          <C>          <C>                <C>
                             ASSETS
Current assets:
     Trade accounts receivable -- net............................   $  350      $  285       $  635       $  (285)(a)      $  350
     Inventories.................................................      206         239          445                           445
     Prepaid expenses and other current assets...................       12          16           28                            28
                                                                   --------   ----------   ----------   -----------        ------
          Total current assets...................................      568         540        1,108          (285)            823
Property, plant and equipment -- net.............................      834       1,305        2,139                         2,139
Other non-current assets:
     Goodwill....................................................                1,155        1,155                         1,155
                                                                                                                5(b)
     Other assets................................................      102          27          129            35(d)          169
                                                                   --------   ----------   ----------   -----------        ------
          Total assets...........................................   $1,504      $3,027       $4,531       $  (245)         $4,286
                                                                   --------   ----------   ----------   -----------        ------
                                                                   --------   ----------   ----------   -----------        ------
                LIABILITIES AND PARTNERS' CAPITAL
Current liabilities:
     Trade accounts payable......................................   $  154      $   64       $  218       $  (218)(h)      $ --
     Current maturities of long term debt........................        2           2            4                             4
                                                                                                             (115)(h)
                                                                                                              (28)(d)
     Other accrued liabilities...................................       52         106          158            38(i)           53
                                                                   --------   ----------   ----------   -----------        ------
          Total current liabilities..............................      208         172          380          (323)             57
Non-current liabilities:
                                                                                                              755(e)
     Long term debt..............................................      743           2          745           (35)(f)       1,465
                                                                                                             (750)(g)
     Indebtedness to Millennium..................................       --       1,000        1,000          (250)(a)          --
     Other liabilities...........................................       36          45           81           (13)(d)          68
                                                                   --------   ----------   ----------   -----------        ------
          Total liabilities......................................      987       1,219        2,206          (616)          1,590
Partners' capital
     Contributed capital.........................................      517       1,808        2,325           716           3,041
     Note receivable from Lyondell...............................                                            (345)(c)        (345)
                                                                   --------   ----------   ----------   -----------        ------
          Total partners' capital................................      517       1,808        2,325           371           2,696
                                                                   --------   ----------   ----------   -----------        ------
          Total liabilities and partners' capital................   $1,504      $3,027       $4,531       $  (245)         $4,286
                                                                   --------   ----------   ----------   -----------        ------
                                                                   --------   ----------   ----------   -----------        ------
</TABLE>
 
- ------------
 
(a) To reflect accounts receivable and certain indebtedness of the Millennium
    Contributed Business to Millennium, neither of which will be contributed to
    the Partnership.
 
(b) To record certain transaction costs related to the formation of the
    Partnership. Such costs will be funded using proceeds from the New Credit
    Facility.
 
(c) To reflect the note receivable from Lyondell as a reduction of Partners'
    capital in accordance with the rules and regulations of the SEC. Such note
    receivable is also reflected as contributed capital.
 
(d) To conform Millennium's major maintenance turnaround policy to Lyondell's
    method which will be adopted by the Partnership. See Note 2 to the financial
    statements of the Lyondell Contributed Business and Note 2 to the financial
    statements of the Millennium Contributed Business. See 'Index to Financial
    Statements.'
 
(e) To reflect borrowings under the New Credit Facility.
 
(f) To reflect a capital contribution by Millennium of $35 representing
    collections on accounts receivable not contributed to the Partnership in
    excess of $250. This amount is reflected as a reduction of borrowings under
    the New Credit Facility.
 
(g) To reflect repayment of the Millennium Contributed Debt, which will be
    assumed by the Partnership ($750).
 
(h) To reflect accounts payable and certain accrued liabilities of Lyondell and
    Millennium which will not be contributed to the Partnership.
 
(i) To reflect the accrual of severance and relocation costs to be paid by the
    Partnership.
 
                                       41
 <PAGE>
<PAGE>
                                THE PARTNERSHIP
                    UNAUDITED PRO FORMA STATEMENTS OF INCOME
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                            SIX MONTHS ENDED JUNE 30, 1997
                                                                   -------------------------------------------------
                                                                        CONTRIBUTED
                                                                         BUSINESSES
                                                                   ----------------------                      PRO
                                                                   LYONDELL    MILLENNIUM    ADJUSTMENTS      FORMA
                                                                   --------    ----------    -----------      ------
 
<S>                                                                <C>         <C>           <C>              <C>
Net sales.......................................................    $1,449       $1,011                       $2,460
Operating costs and expenses:
     Cost of goods sold.........................................     1,134          743                        1,877
     Depreciation and amortization..............................        41           66                          107
     Selling, development and administrative expenses...........        80           53                          133
                                                                   --------    ----------                     ------
Operating income................................................       194          149                          343
                                                                                                $  40(b)
Interest expense................................................       (35)         (40)          (25)(c)        (60)
Interest income.................................................                                   11(d)          11
                                                                   --------    ----------    -----------      ------
Income before income taxes......................................       159          109            26            294
Provision for income taxes......................................        58           48          (106)(e)       --
                                                                   --------    ----------    -----------      ------
Net income......................................................    $  101       $   61         $ 132         $  294
                                                                   --------    ----------    -----------      ------
                                                                   --------    ----------    -----------      ------
</TABLE>
 
<TABLE>
<CAPTION>
                                                                              YEAR ENDED DECEMBER 31, 1996
                                                                    ------------------------------------------------
                                                                    CONTRIBUTED BUSINESSES
                                                                    ----------------------                     PRO
                                                                    LYONDELL    MILLENNIUM    ADJUSTMENTS     FORMA
                                                                    --------    ----------    -----------     ------
                                                                                     (IN MILLIONS)
 
<S>                                                                 <C>         <C>           <C>             <C>
Net sales........................................................    $2,515       $1,860                      $4,375
Operating costs and expenses:
     Cost of goods sold..........................................     2,068        1,381                       3,449
     Depreciation and amortization...............................        67          122                         189
     Selling, development and administrative expenses............       157          109         $   1(a)        267
                                                                    --------    ----------    -----------     ------
Operating income.................................................       223          248            (1)          470
                                                                                                    80(b)
Interest expense.................................................       (65)         (80)          (50)(c)      (115)
Interest income..................................................                                   21(d)         21
                                                                    --------    ----------    -----------     ------
Income before income taxes.......................................       158          168            50           376
Provision for income taxes.......................................        56           76          (132)(e)        --
                                                                    --------    ----------    -----------     ------
Net income.......................................................    $  102       $   92         $ 182        $  376
                                                                    --------    ----------    -----------     ------
                                                                    --------    ----------    -----------     ------
</TABLE>
 
- ------------
 
 (a) To reflect amortization of capitalized transaction costs to be borne by the
     Partnership.
 
 (b) To eliminate interest on the Millennium Contributed Debt, which will be
     assumed and repaid by the Partnership of $1,000 at 8.0% per annum.
 
 (c) To reflect interest on assumed average borrowings of $850 under the New
     Credit Agreement during both periods at an assumed rate of 6.0% per annum
     for the 1997 period and 5.9% per annum for the 1996 period.
 
 (d) To reflect interest income on the $345 note receivable from Lyondell at an
     assumed interest rate of 6.2% per annum for the 1997 period and 6.0% per
     annum for the 1996 period.
 
 (e) To eliminate income tax expense of the Contributed Businesses, which will
     be borne by the partners.
 
                                       42
 <PAGE>
<PAGE>
                BUSINESSES TO BE CONTRIBUTED TO THE PARTNERSHIP
 
LYONDELL
 
     Lyondell will contribute to the Partnership the Lyondell Contributed
Business, which consists of the production, distribution and sale of
petrochemicals and polymers. Its facilities are located in Channelview,
Matagorda County, Mont Belvieu, Pasadena and Victoria, Texas. Lyondell's
interests in Lyondell Methanol and LYONDELL-CITGO Refining will not be
contributed to the Partnership. However, the Partnership will enter into
arrangements (i) to provide operating and other services for Lyondell Methanol,
and (ii) to provide marketing and other services for LYONDELL-CITGO Refining,
all of which will be on commercially reasonable terms.
 
     A more complete description of the businesses which are owned and operated
by Lyondell is included in Lyondell's Annual Report on Form 10-K for the year
ended December 31, 1996 and Lyondell's Quarterly Reports on Form 10-Q for the
quarters ended March 31, 1997 and June 30, 1997. Such reports also include a
'Management's Discussion and Analysis of Financial Conditions and Results of
Operations' section which discusses the businesses that Lyondell is contributing
to the Partnership. See 'Where You Can Find More Information.'
 
     Through the year ended December 31, 1996, Lyondell reported its results of
operations in two segments, petrochemicals and refining. In 1997, Lyondell began
reporting the results of its polymers operations as a separate segment (rather
than as part of the petrochemicals segment).
 
PETROCHEMICALS OPERATIONS
 
     CHANNELVIEW FACILITY. Lyondell's Channelview petrochemical complex (the
'Channelview Facility') is located in Channelview, Texas, 20 miles east of
Houston. The Channelview Facility includes two large olefins plants and related
processing units that produce ethylene, propylene, butadiene, butylenes,
benzene, toluene, hydrogen and certain specialty products, such as isoprene,
dicyclopentadiene, resin oils and piperylenes, along with gasoline blendstocks
and heavy liquid fuels. Lyondell's petrochemicals products are used to
manufacture intermediate chemicals, which are primarily used in a variety of
consumer and industrial products. Petrochemicals are fundamental to many
segments of the economy, including the production of consumer products, housing
components, automotive products and other durable and non-durable goods.
Ethylene is the most significant petrochemical in terms of worldwide production
volume and is the key building block for a large number of chemicals. With the
wide proliferation of end-use products derived from ethylene during the past
several decades, especially as plastics have developed into low-cost, high
performance substitutes for a wide range of materials such as metals and paper,
U.S. ethylene consumption has grown by an average annual rate of more than four
percent.
 
POLYMERS OPERATIONS
 
     BAYPORT FACILITY. The Bayport Facility converts propylene and ethylene into
polypropylene and LDPE that is sold into markets for end use products. The
Bayport Facility is connected by pipeline to Lyondell's Mont Belvieu Facility
for feedstock supply.
 
     MATAGORDA FACILITY. The Matagorda Facility converts ethylene and small
amounts of comonomer into HDPE. In 1996, a significant portion of the ethylene
converted at the Matagorda Facility was supplied by the Channelview Facility via
exchange agreements. The Matagorda Facility features three independent reaction
and finishing process lines that employ the Nissan slurry polymerization
technology. This enables Lyondell to produce a wide variety of resins for blown
film, blow molding and injection molding applications.
 
     VICTORIA FACILITY. The Victoria Facility converts ethylene and small
amounts of comonomer into HDPE resins. In 1996, a significant portion of the
ethylene converted at the Victoria Facility was supplied by the Channelview
Facility via exchange agreements. The Victoria Facility features solution
polymerization technology that minimizes the presence of catalyst residues
resulting in resins with excellent organoleptic properties (no taste or odor)
and extremely low moisture vapor transmission rates. This enables Lyondell to
produce a wide variety of film and injection molding resins for use in consumer
products and industrial applications.
 
                                       43
 <PAGE>
<PAGE>
     POLYMERS TECHNOLOGY CENTER. Research and development is conducted in a
catalyst laboratory with state-of-the-art analytical capabilities in Alvin,
Texas (the 'Technology Center'). The Technology Center provides product and
process technology support for Lyondell's polymers operations and its customers.
 
     The following table outlines the principal products of the Lyondell
Contributed Business and their uses:
 
<TABLE>
<CAPTION>
              PRODUCT                                            PRIMARY USES
- ------------------------------------  ------------------------------------------------------------------
<S>                                   <C>
Ethylene............................  Ethylene is used as a feedstock to manufacture polyethylene which
                                      is used in products such as trash bags, packaging film, toys,
                                      housewares and milk containers. Ethylene also is used to produce
                                      ethylene oxide (used to produce ethylene glycol which is used to
                                      produce antifreeze and polyester fibers), ethylene dichloride
                                      (used to produce polyvinyl chloride for pipe and other vinyl
                                      products), ethylbenzene (used to produce styrene, which in turn is
                                      used to produce polystyrene for packaging and containers) and
                                      alpha olefins (used in the manufacture of detergents, as well as
                                      other intermediate chemicals.)

Propylene...........................  Propylene is used to produce polypropylene, acrylonitrile,
                                      propylene oxide and oxo products. Polypropylene is used in
                                      products such as carpets, food packaging, upholstery, automobile
                                      parts and plastic bottles. Acrylonitrile is used in clothing and
                                      high impact plastics. Propylene oxide is used in polyurethane
                                      foams for furniture and insulation. Oxo products are used in
                                      industrial solvents, as well as other intermediate chemicals.

Butadiene...........................  Butadiene is used to manufacture styrene butadiene rubber and
                                      polybutadiene rubber, which are used in the manufacture of tires,
                                      and other rubber products. Butadiene is also used in the
                                      production of nylon and acrylonitrile-butadiene-styrene plastics.

Aromatics...........................  Aromatics products include benzene and toulene. Benzene is used to
                                      produce styrene, phenol and nylon. Toluene is used as an octane
                                      enhancer for benzene production and in urethane chemicals. These
                                      products are used in the production of plastics, rubber fibers for
                                      carpet and apparel, in gasoline and in polyurethane foams used in
                                      seat cushions.

Specialty Products..................  Specialty products include feedstocks for the production of
                                      various types of hydrocarbon resins and unsaturated polyester
                                      resins. These products are used in the production of inks,
                                      adhesives, paints and varnishes, rubber and fiberglass.

MTBE................................  MTBE is an octane enhancer and clean fuel additive in reformulated
                                      gasoline.

HDPE................................  HDPE is used in plastic films for grocery and merchandise
                                      carry-out sacks, trash can liners, food produce bags and housing
                                      insulation, molded and extruded plastic for packaging food items
                                      and plastic drink cups, safety equipment, detergent/motor oil
                                      bottles.

Polypropylene.......................  Polypropylene is used for fibers for carpets, rugs, upholstery;
                                      housewares; plastic caps and seals for consumer items such as
                                      shampoo and household cleaners.

LDPE................................  LDPE is used for plastic films for packaging items such as ice and
                                      bread, plastic bottles for packaging food and medicines.
</TABLE>
 
                                       44
 <PAGE>
<PAGE>
     The following table shows the current annual rated capacity for certain of
the principal products of the Lyondell Contributed Business.
 
<TABLE>
<CAPTION>
                                                                              RATED CAPACITY(a)
                                                                               AT DECEMBER 31,
PRODUCT                                                                             1996
- --------------------------------------------------------------------------   -------------------
                                                                             (MILLIONS OF POUNDS
                                                                                 PER ANNUM)
 
<S>                                                                          <C>
Ethylene (pounds).........................................................          3,850
Propylene (pounds)........................................................          2,250
Butadiene (pounds)........................................................            615
MTBE (gallons)............................................................            199
Aromatics (gallons).......................................................            130
HDPE......................................................................          1,500(b)
Polypropylene.............................................................            400
LDPE......................................................................            140
</TABLE>
 
- ------------
 
 (a) The term 'rated capacity,' as used in this table and throughout this Joint
     Proxy Statement, is calculated by estimating the number of days in a
     typical year that a production unit of a plant is expected to operate,
     after allowing for downtime for regular maintenance, and multiplying that
     number by an amount equal to the unit's optimal daily output based on the
     design feedstock mix. Because the rated capacity of a production unit is an
     estimated amount, the actual production volumes may be more or less than
     rated capacity.
 
 (b) Lyondell is undertaking a debottleneck project at its Victoria Facility
     that will expand the plant's HDPE capacity by approximately 25% to 575
     million pounds and is scheduled to be completed in 1998. In addition,
     Lyondell has previously announced plans to expand HDPE capacity by an
     additional 440 million pounds.
 
                            ------------------------
 
     MONT BELVIEU FACILITY. Feedstocks for Lyondell's facilities and products
are stored at Lyondell's Mont Belvieu, Texas storage facility ('Mont Belvieu
Facility'). The Mont Belvieu Facility is connected by a comprehensive pipeline
system to the Channelview Facility.
 
     FEEDSTOCKS. The primary feedstocks used in the production of olefins are
natural gas liquids feedstocks including ethane, propane and butane
(collectively, 'NGLs') and naphtha, condensates and gas oils (collectively,
'Petroleum Liquids'). As of January 1, 1997, approximately 40% of domestic
industry-wide ethylene capacity was limited to NGL feedstocks, and the remaining
capacity could process to some extent both NGLs and Petroleum Liquids. Olefins
plants with the flexibility to consume a wide range of feedstocks are better
able to maintain higher levels of profitability during periods of changing
energy and petrochemicals prices than olefin plants that are restricted in their
feedstock processing capability. Feedstock cost is generally the largest element
of total cost for the petrochemicals business.
 
     Petroleum Liquids have had a significant historical variable margin
advantage over ethane and propane. The industry margin differential between
these feedstocks has been typically between one and four cents per pound of
ethylene. Lyondell has the capability to capture this differential at the
Channelview Facility due to its feedstock flexibility. Lyondell's olefins plants
can process feedstocks of 100% Petroleum Liquids or up to 90% NGLs.
 
     Lyondell obtains a portion of its olefins feedstock requirements from
LYONDELL-CITGO Refining (NGLs, naphtha and gas oil) and additional olefins
feedstock in the form of petroleum condensates pursuant to a contract with an
affiliate of a foreign government. The remainder of its Petroleum Liquids
requirements are obtained under short-term contracts or on the spot market from
a variety of foreign and domestic sources. Lyondell also purchases NGLs from a
wide variety of domestic sources, many of which have pipeline connections to
Lyondell's facilities.
 
     The ethylene and propylene converted at the Bayport Facility are supplied
by the Channelview Facility either directly or via exchange arrangements. Under
a supply agreement with Occidental Chemical Company, portions of Lyondell's
ethylene supply needs at the Victoria and Matagorda
 
                                       45
 <PAGE>
<PAGE>
Facilities are supplied by Occidental. In 1996 Lyondell began supplying
significant amounts of ethylene from its Channelview Facility to the Victoria
and Matagorda Facilities via exchange arrangements.
 
     MARKETING, SALES AND DISTRIBUTION. Lyondell sells a majority of its olefins
products to customers with whom it has long-standing relationships. Sales
generally are made pursuant to written agreements which typically provide for
monthly negotiation of price. The parties are contractually committed to monthly
price terms. Nonetheless, in some cases, if the parties fail to agree on a
monthly price, deliveries may be suspended for the month. The contracts
typically require the customer to purchase a specified minimum quantity.
Contract terms are typically three to six years with automatic one or two year
term extension provisions. Some contracts are subject to early termination if
deliveries have been suspended for several months.
 
     Most of Lyondell's ethylene and propylene is shipped or exchanged via an
extensive pipeline system which has connections to numerous Gulf Coast ethylene
and propylene consumers. The pipeline system is owned by ARCO PipeLine Company,
and substantially all of it is leased by Lyondell under long-term leasing
arrangements. Lyondell has exchange agreements with other olefins producers
which allow access to customers who are not directly connected to the pipeline
system. Some propylene is shipped by ocean-going vessel. Butadiene, methanol,
aromatics and other petrochemicals are distributed by pipeline, railcar, truck,
barge or ocean-going vessel.
 
     Lyondell's polymers products are primarily sold to established customers,
many under term contracts, typically having a duration of one to four years. The
remainder is generally sold without contractual term commitments. In either
case, in most of the continuous supply relationships, prices are subject to
change upon mutual agreement between Lyondell and the customer. Polymers are
primarily distributed via railcar. Lyondell owns or leases, pursuant to
long-term lease arrangements, approximately 3,200 railcars for use in its
polymers business.
 
MILLENNIUM
 
     Millennium Petrochemicals, an indirect wholly-owned subsidiary of
Millennium, will contribute to the Partnership the Millennium Contributed
Business, which consists of the production, distribution and sale of ethylene,
polyethylene and related products, polypropylene and other performance polymers
and ethyl alcohol. Its plants are located in Clinton, Iowa; Crockett, Texas;
LaPorte, Texas; Port Arthur, Texas; Chocolate Bayou, Texas; Tuscola, Illinois;
Morris, Illinois; Fairport Harbor, Ohio; Heath, Ohio; Newark, New Jersey and
Anaheim, California, and its research facilities are located in Cincinnati, Ohio
and Morris, Illinois. Certain assets of Millennium Petrochemicals such as those
used to produce VAM, acetic acid and methanol, and Millennium Petrochemicals'
headquarters facility in Cincinnati, Ohio will not be contributed to the
Partnership. See 'The Asset Contribution Agreements -- Excluded Assets.'
Millennium Petrochemicals will also receive $250 million as a result of the
retention of its accounts receivable that relate to petrochemicals products sold
before completion of the Joint Venture Transaction.
 
     A more complete description of these businesses which are owned and
operated by Millennium Petrochemicals is included in Millennium's Annual Report
on Form 10-K for the year ended December 31, 1996 and Millennium's Quarterly
Reports on Form 10-Q for the quarters ended March 31, 1997 and June 30, 1997.
Such reports also include a 'Management's Discussion and Analysis of Financial
Conditions and Results of Operations' section which discusses the businesses
that Millennium is contributing to the Partnership. See 'Where You Can Find More
Information.'
 
     OVERVIEW. The following is a description of the principal products of the
Millennium Contributed Business and their uses:
 
                                       46
 <PAGE>
<PAGE>
 
<TABLE>
<CAPTION>
                  PRODUCT                                           PRIMARY USES
- -------------------------------------------  -----------------------------------------------------------
 
<S>                                          <C>
POLYETHYLENE AND RELATED PRODUCTS:
LDPE.......................................  Packaging for meats and produce, household wraps, toys,
                                             housewares and coatings for paper, milk and juice cartons.
HDPE.......................................  Blow molded bottles for milk, juices and detergents,
                                             industrial drums, injection-molded household goods and
                                             toys, and consumer packaging.
Linear Low Density Polyethylene
  ('LLDPE')................................  Heavy duty bags, stretch wrap, container lids, trash and
                                             merchandise bags and toys.
Ethylene...................................  A raw material for polyethylene and other chemical and
                                             polymer products.
Ethyl Alcohol:
Ethyl Alcohol..............................  An ingredient in personal care products, pharmaceutical and
                                             household cleaning and other consumer products.
Ethyl Ether................................  Laboratory reagents, gasoline and diesel engine starting
                                             fluids and smokeless gun powder.
PERFORMANCE POLYMERS:
Polypropylene..............................  Battery cases, automotive components, packaging materials,
                                             luggage, housewares and appliance parts.
Colors and Concentrates....................  Stock and customer colorants, anti-block, anti-static and
                                             anti-slip additives, ultraviolet inhibitors, foaming
                                             agents, processing aids and flame retardants.
Wire and cable resins......................  Insulation for power cable, communications cable, CATV and
                                             automotive wire.
Adhesive tie layer resins..................  Food and medical packaging.
Hot melt adhesive resins...................  Sealants, caulks and adhesives.
Fuel additives.............................  Diesel fuel pour point depressants.
Rotomolding powders........................  Tanks, ductwork, bins, toys and automotive parts.
Polymeric powders..........................  Coatings for glass, metal, paper, textiles, carpets and
                                             other plastics, as well as processing aids for polyesters.
</TABLE>
 
     The following table sets forth information concerning the annual rated
production capacity, as of December 31, 1996, for the principal products of the
Millennium Contributed Business:
 
<TABLE>
<CAPTION>
                                                                              RATED CAPACITY(a)
                                                                               AT DECEMBER 31,
PRODUCT                                                                             1996
- --------------------------------------------------------------------------   -------------------
                                                                             (MILLIONS OF POUNDS
                                                                                 PER ANNUM)
 
<S>                                                                          <C>
LDPE......................................................................          1,555(b)
LLDPE.....................................................................          1,130(b)
HDPE......................................................................          1,935(b)
Ethylene..................................................................          3,830
Ethyl Alcohol and Ethyl Ether.............................................             52(c)
Performance Polymers......................................................           --  (d)
</TABLE>
 
- ------------
 
 (a) The term 'rated capacity,' as used in this table and throughout this Joint
     Proxy Statement, is defined on page 45.
 
 (b) HDPE rated capacity will be reduced by approximately 120 million pounds as
     of September 30, 1997 and by an additional 120 million pounds by September
     30, 1998. Millennium plans to increase rated capacity of LDPE by 115
     million pounds, of LLDPE by 50 million pounds and of HDPE by 35 million
     pounds between 1999 and year-end 2001 by debottlenecking existing reactors.
 
 (c) Millions of gallons per annum.
 
 (d) Because performance polymers are enhanced grades of polyethylene and
     polypropylene, it is not meaningful to estimate rated capacity of
     performance polymers.
 
                                       47
 <PAGE>
<PAGE>
     POLYETHYLENE AND RELATED PRODUCTS. Millennium Petrochemicals is the largest
United States producer of LDPE, the third largest United States producer of HDPE
and the fourth largest United States producer of LLDPE, based on reported
production capacities.
 
     Millennium Petrochemicals currently manufactures all three types of
polyethylene at its La Porte, Texas production complex. In addition, it
manufactures LDPE at its Morris, Illinois, Port Arthur, Texas and Clinton, Iowa
complexes; HDPE at its Clinton, Iowa and Port Arthur and Chocolate Bayou, Texas
complexes; and LLDPE at its Morris complex. The Morris and Clinton complexes are
the only petrochemical industry polyethylene facilities located in the Midwest
and enjoy a freight cost advantage over Gulf Coast producers in delivering
products to customers in the Midwest and on the East Coast of the United States.
Millennium Petrochemicals' polyethylene manufacturing facilities operated at an
average operating rate (based on capacity) of 86% during 1996 and 85% during
1995 and fiscal 1994. For the six months ended June 30, 1997, such polyethylene
manufacturing facilities operated at an average operating rate (based on
capacity) of 87%.
 
     During 1996, Millennium Petrochemicals completed capital projects that
increased its production capacity with respect to LLDPE and HDPE by
approximately 17% and 11%, respectively, from 1995 levels. These projects, which
were mainly funded prior to the Demerger, include the restart of 250 million
pounds of annual LLDPE capacity at Morris, the conversion of 300 million pounds
of annual LLDPE capacity at Port Arthur to HDPE production and construction of a
480 million pound per annum gas phase LLDPE unit at La Porte. Millennium
Petrochemicals intends to shut down 120 million pounds of HDPE capacity at La
Porte on September 30, 1997, and another 120 million pounds of HDPE capacity at
La Porte on September 30, 1998.
 
     Ethylene is the principal raw material used in the production of
polyethylene. Millennium Petrochemicals is currently capable of producing over
3.8 billion pounds of ethylene per annum at its La Porte, Morris and Clinton
complexes.
 
     In addition to producing its own ethylene, Millennium Petrochemicals has
contracted to purchase significant amounts of ethylene from Gulf Coast producers
under certain long-term agreements at prices based on market prices. Millennium
Petrochemicals sells ethylene on the spot market in excess of its requirements.
Spot prices fluctuate and may be significantly less than, or significantly
greater than, the prices that Millennium Petrochemicals has paid for the
ethylene purchased under its long-term agreements. Millennium Petrochemicals'
ethylene purchase obligations began to decline in December 1996 and will be
eliminated by December 2000, unless Millennium Petrochemicals seeks extensions
or new agreements. Millennium Petrochemicals' purchases of ethylene under these
contracts approximated $183 million in 1996, $207 million in 1995 and $143
million in 1994. Sales of lesser quantities of excess ethylene into the spot
market during the same periods resulted in losses of $13.4 million, $6.1 million
and $6.4 million, respectively.
 
     In July 1996, Millennium and Lyondell announced the execution of a Letter
of Intent with two other olefins producers for the planned construction of the
Joint Olefins Venture. After the withdrawal of one of the participants in
October 1996, Millennium, Lyondell and the other partner are continuing to
evaluate options for the proposed plant, including alternative designs for
utilizing various different feedstock mixes, as well as size, schedule and
participants.
 
     The feedstocks for ethylene used by Millennium Petrochemicals are natural
gas liquids, including ethane, propane and butane. The Millennium Contributed
Business purchases its requirements for these feedstocks from outside sources
(including Lyondell) and converts them into ethylene, propylene and a variety of
marketable by-products at the La Porte, Morris and Clinton plants. While
Millennium Petrochemicals has agreements providing for the supply of these
feedstocks, the contractual prices of these feedstocks vary with market
conditions and are at times highly volatile.
 
     Polyethylene is manufactured in pellet form and shipped in North America
primarily by railcar in 180,000-pound lots. The remainder is shipped in
40,000-pound hopper trucks, 1,000-pound boxes and 50-pound bags. The Millennium
Contributed Business sells its polyethylene products in the United States
primarily through its own sales organization. It generally engages export sales
agents to market its products in the rest of the world. The polyethylene
operations have an extensive customer base.
 
                                       48
 <PAGE>
<PAGE>
     The polyethylene operations of the Millennium Contributed Business are
subject to substantial competition from other United States and non-United
States producers, including some of the world's largest chemical and integrated
oil companies such as Dow Chemical Company, Union Carbide Corporation, Phillips
Petroleum Company, NOVA Corporation, Chevron Corporation, Exxon Corporation,
Lyondell, Eastman Chemical Company, Solvay Polymers, Formosa Plastics and
Westlake Polymers. Millennium Petrochemicals competes in the polyethylene market
on the basis of price, product performance and technical service.
 
     ETHYL ALCOHOL AND ETHYL ETHER. The Millennium Contributed Business produces
synthetic ethyl alcohol at its Tuscola, Illinois plant by a direct hydration
process that combines water and ethylene. Millennium Petrochemicals also owns
and operates plants at Tuscola, Illinois, Newark, New Jersey and Anaheim,
California for denaturing ethyl alcohol by the addition of certain chemicals. In
addition, it produces small volumes of ethyl ether, a by-product of its ethyl
alcohol production, at Tuscola. Tuscola has an annual production capacity of
approximately 50 million gallons of synthetic ethyl alcohol and approximately 2
million gallons of ethyl ether.
 
     PERFORMANCE POLYMERS. The Millennium Contributed Business produces
performance polymer products, which include enhanced grades of polyethylene and
polypropylene. Millennium believes that, over a business cycle, average selling
prices and profit margins for performance polymers tend to be higher than
selling prices and profit margins for higher-volume commodity polyethylenes.
 
     POLYPROPYLENE. The Millennium Contributed Business manufactures
polypropylene at Morris, Illinois using propylene produced as a by-product of
its ethylene production as well as purchased propylene. The plant has the
capacity to produce 280 million pounds of polypropylene annually for various
applications in the automotive, housewares and appliance industries.
 
     COLORS AND CONCENTRATES. The Millennium Contributed Business produces color
and concentrates at its facilities in Crockett, Texas; Fairport Harbor, Ohio and
Heath, Ohio. Color and concentrates are polyethylene compounds impregnated with
additives and/or pigments and sold to converters who mix the compounds with
larger volumes of polymers, including polyethylene, to produce various products.
 
     WIRE AND CABLE RESINS. The Millennium Contributed Business produces
polyethylene and polypropylene resins and compounded resins, used in various
wire and cable applications, including insulation and jacketing for
telecommunications, CATV electrical power cable and automotive wiring.
 
     ADHESIVE TIE LAYER RESINS. The Millennium Contributed Business produces
adhesive tie layer resins which are extrudable adhesive resins used to bond
dissimilar materials in multi-layer structures, such as food and medical
packages.
 
     HOT MELT ADHESIVE RESINS. The Millennium Contributed Business produces hot
melt adhesive resins, which are specialty resins used in the manufacture of
sealants, caulks and adhesives.
 
     ROTOMOLDING POWDERS. The Millennium Contributed Business produces
rotomolding polyethylene powders which are used in rotomolding, a specialized
process for fabricating large hollow plastic objects such as tanks, bins, toys
and automotive parts.
 
     POLYMERIC POWDERS. The Millennium Contributed Business produces polymeric
powders, which are a form of powdered polyethylene used to coat glass, metal,
paper, textiles, carpets and other plastics.
 
                                       49
 <PAGE>
<PAGE>
MANUFACTURING OPERATIONS OF THE PARTNERSHIP
 
     Following the contribution by Lyondell and Millennium of the businesses
described above, the Partnership is expected to be the largest producer of
ethylene and polyethylene in North America. The Partnership will have
manufacturing operations, principal products and annual production capacities as
described in the following table:
 
<TABLE>
<CAPTION>
                 LOCATION                              PRINCIPAL PRODUCTS                   ANNUAL CAPACITY
- -------------------------------------------  ---------------------------------------  ---------------------------
 
<S>                                          <C>                                      <C>
Channelview, Texas.........................  Ethylene                                 3.8 billion pounds
                                             Propylene                                2.2 billion pounds
                                             Butadiene                                615 million pounds
                                             Benzene                                  90 million gallons
                                             Toluene                                  40 million gallons
                                             Dicyclopentadiene ('DCPD')               80 million pounds
                                             Isoprene                                 108 million pounds
                                             Resin oil                                120 million pounds
                                             Piperylenes                              100 million pounds
                                             Alkylate                                 22,000 barrels per day
                                             MTBE                                     13,000 barrels per day
 
Chocolate Bayou, Texas.....................  HDPE                                     400 million pounds
 
Crockett, Texas............................  Wire & cable compounds, color and        120 million pounds
                                             additive concentrates
 
LaPorte, Texas.............................  Ethylene                                 1.74 billion pounds
                                             LDPE                                     395 million pounds
                                             LLDPE                                    480 million pounds
                                             HDPE                                     545 million pounds(a)
 
Matagorda County, Texas....................  HDPE                                     1,050 million pounds
 
Pasadena, Texas (Bayport plant)............  Polypropylene                            400 million pounds
                                             LDPE                                     140 million pounds
 
Port Arthur, Texas.........................  LDPE                                     190 million pounds
                                             HDPE                                     540 million pounds
 
Victoria, Texas............................  HDPE                                     450 million pounds
 
Morris, Illinois...........................  Ethylene                                 1.13 billion pounds
                                             LDPE                                     540 million pounds
                                             LLDPE                                    650 million pounds
                                             Polypropylene                            280 million pounds
 
Tuscola, Illinois..........................  Ethyl alcohol                            50 million gallons
                                             Diethyl ether                            2 million gallons
                                             Compounds for wire & cable               36 million pounds
                                             Microfine polyolefin powders             10 million pounds
 
Clinton, Iowa..............................  Ethylene                                 960 million pounds
                                             LDPE                                     430 million pounds
                                             HDPE                                     450 million pounds
 
Fairport Harbor, Ohio......................  Wire & cable compounds, color            60 million pounds
                                             concentrates
 
Heath, Ohio................................  Color, additive and foam concentrates,   39 million pounds
                                             performance compounds
 
Anaheim, California........................  Denatured alcohol                        (b)
 
Newark, New Jersey.........................  Denatured alcohol                        (b)
</TABLE>
 
- ------------
 
 (a) HDPE rated capacity at La Porte will be reduced by approximately 120
     million pounds as of September 30, 1997 and by an additional 120 million
     pounds by September 30, 1998.
 
 (b) Not available.
 
                                       50
<PAGE>
<PAGE>
                   FINANCING ARRANGEMENTS FOR THE PARTNERSHIP
 
THE NEW CREDIT FACILITY
 
     The Partnership has entered into letter agreements with Bank of America
National Trust and Savings Association ('Bank of America') and The Chase
Manhattan Bank ('Chase Manhattan'), as administrative agents for the purpose of
syndicating a new bank credit facility (the 'New Credit Facility') in the amount
of $1.25 billion. The New Credit Facility will be used (i) to finance the $750
million payment to Millennium in respect of the Millennium Contributed Debt,
(ii) to finance certain capital expenditures of the Partnership, (iii) to meet
the Partnership's working capital needs, and (iv) for general Partnership
purposes. The Closing will not occur until definitive documentation for the
$1.25 billion New Credit Facility has been negotiated and executed and the
conditions precedent to borrowings thereunder have been satisfied.
 
     The Master Transaction Agreement contemplates that the $1.25 billion New
Credit Facility will be structured as a five-year revolving loan bearing
interest at LIBOR plus an appropriate margin based on the credit ratings profile
of the Partnership (with the ability to convert to a fixed interest rate under
certain circumstances). The New Credit Facility will be unsecured and will
contain covenants that are usual and customary for borrowers with investment
grade credit ratings.
 
     Pursuant to the Millennium America Guarantee, Millennium America will
guarantee $750 million of principal and interest under the New Credit Facility.
The Millennium America Guarantee will be a senior obligation of Millennium
America, but the lenders under the New Credit Facility will not be permitted to
proceed against Millennium America thereunder until they have exhausted their
remedies against the Partnership. The Millennium America Guarantee will remain
in effect indefinitely, but, at any time after the seventh anniversary of the
Closing Date, Millennium may elect to terminate the Millennium America Guarantee
if (i) the Partnership's ratio of total debt to total capitalization is then
lower than such ratio as at December 31, 1998, (ii) the Partnership's ratio of
EBITDA to Net Interest Coverage for the most-recent 12 month period is at least
105% of such ratio for the 12 month period ending December 31, 1998, (iii) the
Partnership is not then in default in the payment of principal of, or interest
on, any indebtedness in excess of $10 million and (iv) the Partnership is not
then in default in respect of any covenants relating to any indebtedness in
excess of $10 million. In addition, if Millennium GP and Millennium LP sell all
of their respective interests in the Partnership to an unaffiliated third party
at any time, Millennium America may elect to terminate the Millennium America
Guarantee if, at the time of such sale, the Partnership has an investment grade
credit rating or the fair market value of the Partnership's assets is at least
140% of the gross amount of its liabilities. If the Partnership refinances any
part of the tranche of the New Credit Facility that benefits from the Millennium
America Guarantee, the Millennium America Guarantee will extend to up to $750
million of indebtedness obtained through such refinancing.
 
LYONDELL NOTE
 
     At the Closing, the Partnership will receive a note (the 'Lyondell Note')
in the principal amount of $345 million issued by Lyondell LP and fully and
unconditionally guaranteed by Lyondell. Both the note and the guarantee will be
senior obligations of Lyondell LP or Lyondell, as the case may be, entitled to
equal and ratable security with any holders of secured debt that may be issued
by Lyondell LP or Lyondell, as the case may be (subject to customary
exceptions). The Lyondell Note will mature on the earlier of (i) the second
anniversary of the Closing or (ii) the thirtieth day following a financing of
LYONDELL-CITGO Refining which results in the payment of LYONDELL-CITGO
Refining's existing $450 million term loan and a distribution to Lyondell of at
least $345 million.
 
     The Lyondell Note will bear interest at LIBOR plus an appropriate margin.
In the event of a default under the Lyondell Note, unless otherwise agreed by
two representatives of Millennium on the Partnership Governance Committee, any
amount otherwise distributable by the Partnership to Lyondell GP or Lyondell LP
will be retained by the Partnership and deemed to be a payment under the
Lyondell Note.
 
     The Lyondell Note will include cross default provisions relating to all
other Lyondell indebtedness exceeding $25 million (including Lyondell
indebtedness assumed by the Partnership, if a default is
 
                                       51
 <PAGE>
<PAGE>
caused by an action or failure to act on the part of Lyondell). The Lyondell
Note will be prepayable at any time, without penalty or premium.
 
MILLENNIUM CONTRIBUTED DEBT
 
     The Partnership will assume the $750 million of Millennium Contributed Debt
at Closing. The Millennium Contributed Debt, which is an intercompany obligation
owed by the Millennium Contributed Business to a subsidiary of Millennium, will
be repaid in cash at Closing, using proceeds of the New Credit Facility.
Millennium intends to use the proceeds of such repayment, as well as $250
million realized from its retention of certain accounts receivable, to reduce
its bank debt.
 
ASSUMED LYONDELL DEBT
 
     At the Closing, the Partnership will assume primary liability for $745
million of public debt and medium-term notes of Lyondell. This debt consists of:
(i) $150 million of notes due in 1999; (ii) $100 million of notes due in 2002;
(iii) $150 million of notes due in 2006; (iv) $150 million of debentures due in
2026; and (v) $195 million of medium-term notes due from 1998 to 2005. Lyondell
will also continue to be liable on such debt until its maturity.
 
     The notes due in 1999 and the medium-term notes contain provisions ('Put
Rights') that would allow the holders to require repurchase of the debt upon the
occurrence of certain events combined with specified declines in public ratings.
Lyondell has agreed to indemnify the Partnership if any action by Lyondell
triggers the repurchase rights, but only to the extent the Partnership incurs an
economic loss directly as a result of the occurrence of such events.
 
LIQUIDITY AND CAPITAL RESOURCES
 
     On the Closing Date the Partnership will repay to Millennium the $750
million of Millennium Contributed Debt using proceeds from the New Credit
Facility. In addition, since the accounts receivable of the Millennium
Contributed Business are not being contributed to the Partnership, the funds
otherwise available for reinvestment into the Partnership from the collection of
such receivables will need to be obtained from further borrowings under the
Partnership's credit facilities. Accordingly, the Partnership is expected to
have $1.745 billion of debt, after giving effect to these further borrowings and
the debt of $745 million assumed from Lyondell. Based on this debt level, it is
expected that the Partnership will have a debt to capitalization ratio of
approximately 39%.
 
     Through June 30, 1997, Lyondell and Millennium financed the operations and
capital and other expenditures of the Lyondell Contributed Business and the
Millennium Contributed Business, respectively, from a combination of cash
generated from their respective operations and external borrowings. These
arrangements will continue to be in effect until the Closing.
 
     The funding of the Partnership's operations, including capital plans,
subsequent to the Closing Date will be obtained from (i) cash generated from
operations, (ii) additional borrowings under its $1.25 billion New Credit
Facility or other available credit facilities and (iii) if necessary, loans or
additional capital contributions from the partners, as authorized by the
Partnership Governance Committee. The Partnership's ability to generate cash
from operations will depend upon numerous business factors, some of which are
outside the control of the Partnership, including industry cyclicality
(resulting from industry-wide capacity additions, changes in general economic
conditions and other conditions) and price volatility of certain raw materials.
It is anticipated that sufficient funds will be generated from the Partnership's
operations and from availability under the New Credit Facility to fund its
operations, interest expense and capital plans.
 
     As a result of the significant Synergies expected to be realized from
combining the Lyondell and Millennium Contributed Businesses, it is anticipated
that improved cash flows will result from operating these businesses through the
Partnership rather than separately. Accordingly, the Partnership will make
monthly distributions to its partners of any and all available cash in excess of
its operating, debt service and capital needs for a specified period.
 
                                       52
<PAGE>
<PAGE>
                        THE MASTER TRANSACTION AGREEMENT
 
     The following is a summary of the material provisions of the Master
Transaction Agreement, which has been filed with the Securities and Exchange
Commission (the 'SEC') and is incorporated herein by reference. This summary is
qualified in its entirety by reference to the full and complete text of the
Master Transaction Agreement. All holders of Lyondell Common Stock and
Millennium Common Stock are encouraged to read the Master Transaction Agreement
carefully. See 'Where You Can Find More Information.'
 
GENERAL
 
     Pursuant to the Master Transaction Agreement, which was executed on July
25, 1997, Lyondell and Millennium agreed (i) to cause certain of their
subsidiaries, as soon as practicable, to form the Partnership, (ii) to execute
and deliver the Partnership Agreement and (iii) to make initial cash
contributions to the Partnership aggregating $1,000,000. In exchange for a
contribution of $570,000, in accordance with the Master Transaction Agreement,
Lyondell GP and Lyondell LP have received interests in the Partnership
representing, in the aggregate, 57% of the interests in the Partnership. In
exchange for a contribution of $430,000, Millennium GP and Millennium LP have
received interests in the Partnership representing, in the aggregate, 43% of the
interests in the Partnership. See 'The Partnership Agreement -- General.'
 
     In addition, Lyondell and Millennium have agreed to cause the execution and
delivery by the appropriate parties at or prior to the Closing of (i) the Asset
Contribution Agreements and the Parent Agreement (together with the Partnership
Agreement, the 'Tier 1 Agreements') and (ii) a variety of other agreements that
will be negotiated by Lyondell and Millennium prior to Closing, which will
relate, among other things, (a) to services, utilities and infrastructure to be
shared or supplied between the Partnership and Lyondell or Millennium and (b) to
the transfer of assets and assumed liabilities contemplated by the Asset
Contribution Agreements (the 'Tier 2 Agreements' and, together with the Tier 1
Agreements, the 'Related Agreements').
 
     The Master Transaction Agreement contemplates that, pursuant to the Asset
Contribution Agreements, Lyondell and Millennium shall on the Closing Date make
or cause to be made the contributions of assets contemplated thereby, subject to
the assumption of liabilities contemplated thereby. The assets being contributed
to the Partnership by each party, together with the liabilities of such party
being assumed by the Partnership, are referred to as such party's 'Contributed
Business.' In addition, Lyondell LP shall execute and deliver to the Partnership
on the Closing Date the Lyondell Note in the principal amount of $345 million.
The Lyondell Note will be guaranteed by Lyondell pursuant to the Parent
Agreement.
 
     The Master Transaction Agreement further contemplates that, on or prior to
the Closing Date, Lyondell and Millennium shall cause the Partnership to enter
into a bank credit agreement or agreements providing for (i) a five-year
revolving loan facility in an aggregate principal amount of $1.0 billion and
(ii) a working capital facility in an aggregate principal amount of $250
million. On the Closing Date, using the proceeds of a loan under the five-year
loan facility referred to in clause (i), the Partnership shall repay in full
$750 million in respect of the Millennium Contributed Debt.
 
CLOSING DATE
 
     The Closing of the transactions contemplated by the Master Transaction
Agreement is expected to take place on the first day of the first calendar month
following the satisfaction or waiver of all of the conditions described below
under 'Conditions to Closing.' Lyondell and Millennium anticipate that the
Closing will occur on or before January 1, 1998.
 
CERTAIN COVENANTS AND AGREEMENTS
 
     The Master Transaction Agreement contains certain covenants and agreements
between Lyondell and Millennium, including without limitation, the following:
 
                                       53
 <PAGE>
<PAGE>
     CONDUCT OF THE CONTRIBUTED BUSINESSES PENDING THE CLOSING DATE. Lyondell
and Millennium each have agreed that, except as required or contemplated by the
Master Transaction Agreement or otherwise consented to or approved in writing by
the other party, during the period commencing on July 25, 1997 and ending on the
Closing Date, it will and will cause its affiliates to: (i) use its commercially
reasonable efforts to operate and maintain its Contributed Business in all
material respects only in the usual, regular and ordinary manner consistent with
past practice (including undertaking scheduled or necessary 'turnarounds' or
other maintenance work and including offsite storage, treatment and disposal of
chemical substances generated prior to the Closing) and, to the extent
consistent with such operation and maintenance, use commercially reasonable
efforts to preserve the present business organization of its Contributed
Business intact, keep available the services of, and good relations with, the
present employees and preserve present relationships with all persons having
business dealings with its Contributed Business, except in each case for such
matters that, individually and in the aggregate, do not and are not reasonably
likely to have a material adverse effect on the financial condition, results of
operations, assets or business of its Contributed Business taken as a whole (a
'Material Adverse Effect'); (ii) maintain its or their books, accounts and
records relating to its Contributed Business in the usual, regular and ordinary
manner, on a basis consistent with past practice, comply in all material
respects with all legal requirements and contractual obligations applicable to
its Contributed Business or to the conduct of its Contributed Business and
perform all of its or their material obligations relating to its Contributed
Business; (iii) not (a) modify or change in any material respect any of the
assets that will be contributed to the Partnership (its 'Contributed Assets') or
dispose of any material Contributed Asset except for (1) inventory, equipment,
supplies and other Contributed Assets sold or otherwise disposed of in the
ordinary course of business and (2) any Contributed Assets that in the ordinary
course of business are replaced with substantially similar Contributed Assets,
(b) except in the ordinary course of business after consultation with the other
party, (1) enter into any contract, commitment or agreement that would be
material to the operation of its Contributed Business or use of the Contributed
Assets or, except as expressly contemplated by the Master Transaction Agreement
or expressly contemplated by or required pursuant to their respective terms,
modify or change in any material respect any obligation under any such contract,
commitment or agreement, (2) modify or change in any material respect any
obligation under its government licenses, or (3) modify or change in any
material respect the manner in which the products produced by its Contributed
Business are marketed and sold, or (c) enter into interest rate protection or
other hedging agreements (except for hydrocarbon hedging agreements entered into
in the ordinary course and expiring prior to June 30, 1998) relating to its
Contributed Business; (iv) not waive any material claims or rights relating to
its Contributed Business; (v) after obtaining knowledge thereof, give notice to
the other party of any claim or litigation (threatened or instituted) or any
other event or occurrence which could reasonably be expected to have a Material
Adverse Effect on its Contributed Assets or Contributed Business, other than
events, occurrences or other matters arising from any change in the general
economic or political conditions or any change in raw materials prices, product
prices, industry capacity or other matter of industrywide application that
affects both parties in a substantially similar way; (vi) not take any action
that is reasonably likely to result in its representations and warranties in the
Master Transaction Agreement, or in the form of Asset Contribution Agreement of
such party, not being true in all material respects as of the Closing Date; and
(vii) not agree, whether in writing or otherwise, to take any action referred to
above, provided, however, that prior to the Closing Date Lyondell and Millennium
will act independently of each other in making decisions as to the research and
development, raw materials, manufacturing, pricing, marketing and distribution
of their products.
 
     ALTERNATIVE PROPOSALS. Each of Lyondell and Millennium has agreed that,
prior to the Closing Date or earlier termination of the Master Transaction
Agreement, it shall not, and shall not permit any of its Affiliates to, and it
shall, and shall cause each of its Affiliates to, cause each officer, director
and employee of itself and its affiliates, and each attorney, accountant,
investment banker, financial advisor and other agent retained by them, not to,
directly or indirectly, initiate, solicit or encourage the submission of any
proposal or offer to acquire or operate all or any material part of its
Contributed Business or to acquire any person (including Lyondell or Millennium,
as applicable) that directly or indirectly owns all or any part of its
Contributed Business, whether by merger, share exchange, purchase of stock,
purchase of assets, tender offer, joint venture or otherwise, and whether for
cash, securities or
 
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any other consideration or combination thereof, if such transaction would be
materially inconsistent with or preclusive of the transactions contemplated by
the Master Transaction Agreement (any such inconsistent or preclusive
transaction being referred to herein as an 'Alternative Transaction'). Lyondell
and Millennium also agreed to immediately cease and cause to be terminated any
existing initiation, solicitation, encouragement, discussions or negotiations
with parties other than the other party commenced prior to July 25, 1997 with
respect to Alternative Transactions.
 
     Notwithstanding the foregoing, in response to a proposal for an Alternative
Transaction (an 'Alternative Proposal') that is unsolicited and made after July
25, 1997, (i) Lyondell and Millennium may engage in discussions or negotiations
regarding such Alternative Proposal with the person who makes such Alternative
Proposal, and (ii) Lyondell and Millennium may furnish to any such person
(subject to the execution of a confidentiality agreement) confidential or
non-public information concerning such party or its affiliates.
 
     Lyondell and Millennium have agreed to immediately notify each other of the
receipt of any Alternative Proposal or any request for confidential or
non-public information relating to such party or its affiliates in connection
with an Alternative Proposal or for access to the properties, books or records
of such party or any affiliate by any person that it is considering making, or
has made, an Alternative Proposal.
 
     EMPLOYEE MATTERS. Lyondell and Millennium have agreed that substantially
all of the employees of Lyondell and Millennium Petrochemicals who are
associated with the Contributed Businesses shall be offered employment with the
Partnership. Staffing consolidations and reductions in redundant functions will
take place as part of achieving the expected synergies of the new venture.
 
     CLOSING AMENDMENTS CERTIFICATE. At or immediately prior to the Closing,
each of Lyondell and Millennium shall complete and deliver to the other party
and to the Partnership an executed statement, signed by a duly authorized
officer of Lyondell or Millennium, setting forth all amendments and additions to
the Master Transaction Agreement or the Related Agreements or to the schedules
and exhibits thereto (if any) that such party believes in good faith to be
necessary to make the representations and warranties of itself and its
affiliates contained in the Master Transaction Agreement or the Related
Agreements true and correct in all respects (other than such matters as are,
individually and in the aggregate, immaterial to its Contributed Business) as of
the Closing (such party's 'Closing Amendments Certificate'). Each of Lyondell
and Millennium shall examine any such Closing Amendments Certificate presented
to it by the other party, and if it is acceptable to such examining party (or if
such examining party is willing to waive the condition that such Closing
Amendments Certificate be acceptable to it) the examining party shall also
execute it, whereupon the amendments and additions set forth therein with
respect to the Master Transaction Agreement and the schedules and exhibits
thereto shall become effective for all purposes and the amendments and additions
set forth therein with respect to the Related Agreements and the schedules and
exhibits thereto shall be effected prior to the execution and delivery thereof
so as to be effective for all purposes from and after the Closing.
 
     CERTAIN OTHER COVENANTS. In addition to the covenants and agreements
described above, Lyondell and Millennium have agreed, among other things: (i) to
give each other and their respective representatives reasonable access to the
officers, plants, properties, books and records relating to its Contributed
Business and to furnish certain other information; (ii) to act in good faith and
to use commercially reasonable efforts to take, or cause to be taken, all
actions and to do, or cause to be done, all things necessary, proper or
advisable to consummate and make effective the transactions contemplated by the
Master Transaction Agreement and under the Related Agreements to be entered into
by it or its affiliates at Closing and to confirm that such transactions have
been accomplished; (iii) to use its commercially reasonable efforts to procure
all consents that are necessary to transfer its Contributed Business to the
Partnership; (iv) to notify the other party and keep it advised as to any
litigation or administrative proceeding that is either pending or, to its
knowledge, threatened against it which challenges the transactions contemplated
by the Master Transaction Agreement, any material damage to or destruction of
its Contributed Business, and any fact of which it has knowledge that indicates
that any condition to Closing is not likely to be satisfied in a timely fashion;
(v) to call a meeting of its stockholders to be held as promptly as practicable
for the purpose of voting upon the
 
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transfer of its Contributed Business, through its Board of Directors to
recommend to its stockholders approval of such matters and not rescind such
recommendation, and to use commercially reasonable efforts to obtain approval of
the transfer of its Contributed Business by its stockholders; and (vi) not to
take any material action inconsistent with its obligations under the Master
Transaction Agreement or which could materially hinder or delay the consummation
of the Closing.
 
CONDITIONS TO CLOSING
 
     The respective obligations of Lyondell and Millennium to effect the Joint
Venture Transaction are subject to the following conditions, among others:
 
     CONDITIONS PRECEDENT TO OBLIGATIONS OF BOTH PARTIES. The respective
obligations of Lyondell and Millennium to consummate the transactions
contemplated by the Master Transaction Agreement are subject to the satisfaction
on or prior to the Closing Date of each of the following conditions: (i) no
preliminary or permanent injunction or other order issued by any federal or
state court of competent jurisdiction in the United States or by any United
States federal or state governmental or regulatory body or any statute, rule,
regulation or executive order promulgated or enacted by any United States
federal or state governmental authority shall be in effect which materially
restrains, enjoins or otherwise prohibits (a) the transactions contemplated by
the Master Transaction Agreement; (b) the ownership by the Partnership
(including enjoyment of any rights relating thereto) of the Contributed
Businesses at and after the Closing; or (c) the operation of the Contributed
Businesses by the Partnership at and after the Closing; and no proceeding
seeking any such injunction or order shall be pending; provided, that before any
determination is made to the effect that this condition has not been satisfied,
Lyondell and Millennium shall each use commercially reasonable efforts to have
such order or injunction lifted, vacated or dismissed; (ii) Lyondell and
Millennium shall have reached agreement with respect to definitive execution
forms of the Tier 2 Agreements; (iii) Lyondell and Millennium shall have
obtained and effected all government licenses and consents required from any
governmental authority for the consummation of the transactions contemplated
under the Master Transaction Agreement and under the Related Agreements to be
entered into at the Closing and required to allow for the prudent and
uninterrupted operation of the Contributed Businesses by the Partnership after
the Closing in a manner consistent with past practices, except for those
government licenses and consents, the absence of which is not, in the aggregate,
reasonably likely to have a Material Adverse Effect; (iv) the stockholders of
Lyondell shall have duly approved the transfer of Lyondell's Contributed
Business to the Partnership, and the stockholders of Millennium shall have duly
approved the transfer of Millennium's Contributed Business to the Partnership;
(v) the Partnership shall have entered into the bank credit agreement or
agreements contemplated by the Master Transaction Agreement and the conditions
precedent to the availability of funds thereunder shall have been satisfied
(subject only to the closing of the transactions contemplated by the Master
Transaction Agreement); and (vi) Lyondell and Millennium shall have agreed upon
the initial five-year Strategic Plan and the initial Annual Budget for the
Partnership, as contemplated by the Partnership Agreement.
 
     CONDITIONS PRECEDENT TO OBLIGATIONS OF LYONDELL. The obligations of
Lyondell under the Master Transaction Agreement are subject to the satisfaction
(or waiver by Lyondell) on or prior to the Closing Date of each of the following
conditions: (i) Millennium's Closing Amendments Certificate (if any) shall have
been acceptable to Lyondell; (ii) notwithstanding any investigation, inspection
or evaluation conducted or notice or knowledge obtained by Lyondell (including
any knowledge obtained as a result of receipt of a Closing Amendments
Certificate), all representations and warranties (as amended pursuant to
Millennium's Closing Amendments Certificate, if applicable) of Millennium and
its affiliates contained in the Master Transaction Agreement and the Related
Agreements that contain qualifications and exceptions relating to materiality or
Material Adverse Effect shall be true and correct on and as of the Closing Date,
and all other representations and warranties of Millennium and its affiliates
contained in such agreements shall be true and correct in all material respects
as of the Closing Date, in each case with the same force and effect as though
such representations and warranties had been made on and as of the Closing Date;
(iii) Millennium and its affiliates shall in all material respects have
performed and complied with all obligations and agreements contained in the
Master Transaction Agreement, and executed all agreements and documents
(including the Tier 1 Agreements and the Tier 2 Agreements)
 
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to be performed, complied with or executed by it or them on or prior to the
Closing Date; (iv) no event, occurrence or other matter shall have occurred that
is reasonably likely to have a Material Adverse Effect with respect to the
Contributed Business of Millennium, provided that this determination shall be
made without regard to any change in general economic or political conditions or
any change in raw materials prices, products prices, industry capacity or other
matter of industry-wide application that affects the Contributed Businesses of
both parties in a substantially similar way; (v) certain consents of third
parties shall have been obtained; and (vi) Lyondell shall have received a
certificate, dated the Closing Date, signed by the President or a Vice President
of Millennium to the effect that, to the knowledge of Millennium, the conditions
specified in the above clauses have been fulfilled.
 
     CONDITIONS PRECEDENT TO OBLIGATIONS OF MILLENNIUM. The obligations of
Millennium under the Master Transaction Agreement are subject to the
satisfaction (or waiver by Millennium) on or prior to the Closing Date of each
of the following conditions: (i) Lyondell's Closing Amendments Certificate (if
any) shall have been acceptable to Millennium (ii) notwithstanding any
investigation, inspection or evaluation conducted or notice or knowledge
obtained by Millennium (including any knowledge obtained as a result of receipt
of a Closing Amendments Certificate), all representations and warranties (as
amended pursuant to Lyondell's Closing Amendments Certificate, if applicable) of
Lyondell and its affiliates contained in the Master Transaction Agreement and
the Related Agreements that contain qualifications and exceptions relating to
materiality or Material Adverse Effect shall be true and correct on and as of
the Closing Date, and all other representations and warranties of Lyondell and
its affiliates contained in such agreements shall be true and correct in all
material respects as of the Closing Date, in each case with the same force and
effect as though such representations and warranties had been made on and as of
the Closing Date; (iii) Lyondell and its affiliates shall in all material
respects have performed and complied with all obligations and agreements
contained in the Master Transaction Agreement and executed all agreements and
documents (including the Tier 1 Agreements and the Tier 2 Agreements) to be
performed, complied with or executed by it or them on or prior to the Closing
Date; (iv) after the date of the Master Transaction Agreement, no event,
occurrence or other matter shall have occurred that is reasonably likely to have
a Material Adverse Effect with respect to the Contributed Business of Lyondell,
provided that this determination shall be made without regard to any change in
general economic or political conditions or any change in raw materials prices,
product prices, industry capacity or other matter of industry-wide application
that affects the Contributed Businesses of both parties in a substantially
similar way; (v) certain consents of third parties shall have been obtained,
including consents to certain amendments or waivers of certain provisions of the
indentures governing each of Millennium America Inc.'s 2.39% Senior Exchangeable
Discount Notes Due 2001, 7% Senior Notes due November 15, 2006 and 7 5/8% Senior
Debentures due November 15, 2026; and (vi) Millennium shall have received a
certificate, dated the Closing Date, signed by the President or a Vice President
of Lyondell to the effect that, to the knowledge of Lyondell, the conditions
specified in the above clauses have been fulfilled.
 
TERMINATION
 
     TERMINATION. The Master Transaction Agreement may be terminated and the
transactions contemplated therein and in the Related Agreements may be abandoned
at any time prior to the Closing: (i) by the written consent of both Lyondell
and Millennium; (ii) by Lyondell if there has been a material misrepresentation
or a breach of an agreement by Millennium in the Master Transaction Agreement
that (a) if such misrepresentation or breach existed on the Closing Date, would
constitute a failure to satisfy the conditions to Closing set forth above under
'Conditions Precedent to Obligations of Lyondell' and (b) has not been cured and
cannot reasonably be cured within 30 days after all other conditions to Closing
have been satisfied; (iii) by Millennium if there has been a material
misrepresentation or a breach of an agreement by Lyondell in the Master
Transaction Agreement that (a) if such misrepresentation or breach existed on
the Closing Date, would constitute a failure to satisfy the conditions to
Closing set forth in above under 'Conditions Precedent to Obligations of
Millennium' and (b) has not been cured and cannot reasonably be cured within 30
days after all other conditions to Closing have been satisfied; (iv) by Lyondell
or by Millennium if, after July 25, 1997 and prior to the Closing, any final,
non-appealable order or injunction shall be issued by any federal or state court
of competent jurisdiction in the United States or by any United States
Authority, or any legal requirement
 
                                       57
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shall be promulgated or enacted by any United States Authority, that would have
the effect of prohibiting or making unlawful the performance of this Agreement,
the execution, delivery or performance of any Related Agreement or the
consummation of the Closing; (v) by either Lyondell or Millennium in the event
that the Closing does not occur for any reason on or before March 31, 1998;
provided, however, that if the Closing does not occur due to the act or omission
of one of the parties, that party may not terminate the Master Transaction
Agreement pursuant to the provisions of this clause; (vi) by Lyondell, upon
approval of the Lyondell Board of Directors, if prior to the Closing Date (a)
without violation of Lyondell's covenant regarding Alternative Proposals,
Lyondell shall have received after the date hereof an Alternative Proposal, (b)
the Lyondell Board of Directors shall have determined, in the exercise of its
good faith judgment and after consultation with its legal counsel and receipt of
a written opinion from its financial advisors, that the Alternative Transaction
contemplated by such Alternative Proposal (if consummated pursuant to its terms)
would be materially more favorable from a financial point of view to Lyondell or
its stockholders, as applicable, than the transactions contemplated by the
Master Transaction Agreement and (c) Lyondell shall have given Millennium at
least five business days' prior written notice of the material terms and
conditions of such Alternative Proposal and of its intention to terminate the
Master Transaction Agreement pursuant to this clause, in order to effect such
Alternative Proposal; provided, however, that such termination under this clause
shall not be effective, and Lyondell shall not be entitled to enter into a
definitive agreement providing for an Alternative Transaction, until Lyondell
has made payment to Millennium of the termination fee required to be paid as
described below; (vii) by Millennium, upon approval of the Millennium Board of
Directors, if prior to the Closing Date (a) without violation of Millennium's
covenant regarding Alternative Proposals, Millennium shall have received after
the date hereof an Alternative Proposal, (b) the Millennium Board of Directors
shall have determined, in the exercise of its good faith judgment and after
consultation with its legal counsel and receipt of a written opinion from its
financial advisors, that the Alternative Transaction contemplated by such
Alternative Proposal (if consummated pursuant to its terms) would be materially
more favorable from a financial point of view to Millennium or its stockholders,
as applicable, than the transactions contemplated by the Master Transaction
Agreement and (c) Millennium shall have given Lyondell at least five business
days' prior written notice of the material terms and conditions of such
Alternative Proposal and of its intention to terminate the Master Transaction
Agreement pursuant to this clause, in order to effect such Alternative Proposal;
provided, however, that such termination under this clause shall not be
effective, and Millennium shall not be entitled to enter into a definitive
agreement providing for an Alternative Transaction, until Millennium has made
payment to Lyondell of the fee required to be paid as described below; (viii) by
Lyondell, if the Millennium Board of Directors shall have resolved to accept or
shall have recommended to the Millennium stockholders an Alternative Proposal or
shall have withdrawn or adversely modified or taken a public position materially
inconsistent with its approval or recommendation to the stockholders of
Millennium of the transfer of its Contributed Business contemplated by the
Master Transaction Agreement; (ix) by Millennium, if the Lyondell Board of
Directors shall have resolved to accept or shall have recommended to the
Lyondell stockholders an Alternative Proposal or shall have withdrawn or
adversely modified or taken a public position materially inconsistent with its
approval or recommendation to the stockholders of Lyondell of the transfer of
its Contributed Business contemplated by the Master Transaction Agreement; (x)
by Lyondell, if (a) a Change of Control of Millennium shall have occurred, (b)
Millennium shall have entered into a definitive agreement providing for, or
publicly announced its intention to effect, any transaction involving a Change
of Control of Millennium or (c) a tender offer or exchange offer shall have been
commenced or publicly announced that, if consummated, would have the effect with
respect to Millennium described in clause (iii) of the definition of 'Change of
Control' below; (xi) by Millennium, if (a) a Change of Control of Lyondell shall
have occurred, (b) Lyondell shall have entered into a definitive agreement
providing for, or publicly announced its intention to effect, any transaction
involving a Change of Control of Lyondell or (c) a tender offer or exchange
offer shall have been commenced or publicly announced that, if consummated,
would have the effect with respect to Lyondell described in clause (iii) of the
definition of 'Change of Control;' and (xii) by either Lyondell or Millennium if
the approval of the stockholders of such party or the other party contemplated
by the Master Transaction Agreement is not obtained at the applicable
stockholders meeting, including adjournments thereof.
 
                                       58
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     'Change of Control' means with respect to Lyondell or Millennium, the
occurrence of any of the following events: (i) there shall be consummated any
consolidation, merger or share exchange of such party (a) in which such party is
not the continuing or surviving person (other than a consolidation, merger or
share exchange with a wholly owned subsidiary of such party in which all shares
of common stock of such party outstanding immediately prior to the effectiveness
thereof are changed into or exchanged for the same number of shares of common
stock of such subsidiary) or (b) pursuant to which the common stock of such
party is converted into cash, securities or other property, other than, in each
case, a consolidation, merger or share exchange of such party in which the
holders of the common stock immediately prior to the consolidation, merger or
share exchange hold, directly or indirectly, at least a majority of the voting
power and common equity of the continuing or surviving person immediately after
such consolidation, merger or share exchange; (ii) all or substantially all of
such party's properties and assets on a consolidated basis are sold or otherwise
disposed of to any person or persons in any one transaction or a series of
transactions, other than as contemplated by the Master Transaction Agreement; or
(iii) any person or any persons acting together which would constitute a 'group'
for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended
(the 'Exchange Act') (other than such party, any subsidiary of such party, any
employee stock purchase plan, stock option plan or other stock incentive plan or
program, retirement plan or automatic dividend reinvestment plan or any
substantially similar plan of such party or any subsidiary of such party or any
person holding securities of such party for or pursuant to the terms of any such
employee benefit plan), together with any affiliates thereof, shall acquire
beneficial ownership (as defined in Rule 13d-3 under the Exchange Act of 50% or
more of the voting stock of such party.
 
     EFFECT OF TERMINATION. In the event of any termination of the Master
Transaction Agreement as provided above, the Master Transaction Agreement shall
forthwith become wholly void and of no further force and effect and there shall
be no liability on the part of any party, its subsidiaries or their respective
officers or directors; provided, however, that upon any such termination the
obligations of the parties with respect to termination fees, expenses and
confidentiality under the Master Transaction Agreement shall remain in full
force and effect and, if the Partnership has been formed, the parties shall
dissolve it, or shall cause it to be dissolved; and provided, further, that
nothing in the Master Transaction Agreement will relieve any party from
liability for damages for any breach of the Master Transaction Agreement.
 
     TERMINATION FEES. If the Master Transaction Agreement is terminated by
Lyondell pursuant to clause (vi) under 'Termination' or by Millennium pursuant
to clause (ix) or (xi), then Lyondell shall pay Millennium a fee of $40 million;
provided, however, that no fee shall be payable following a termination of the
Master Transaction Agreement pursuant to clause (ix)(c) unless and until the
relevant tender offer or exchange offer has been consummated and a Change of
Control of Lyondell described in clause (iii) of the definition of 'Change of
Control' has occurred. See ' -- Termination.'
 
     If the Master Transaction Agreement is terminated by Millennium pursuant to
clause (vii) under 'Termination' or by Lyondell pursuant to clause (viii) or
(x), then Millennium shall pay Lyondell a fee of $40 million; provided, however,
that no fee shall be payable following a termination of this Agreement pursuant
to clause (x)(c) unless and until the relevant tender offer or exchange offer
has been consummated and a Change of Control of Millennium described in clause
(iii) of the definition of 'Change of Control' has occurred. See
' -- Termination.'
 
     If (i) the Master Transaction Agreement is terminated prior to the
occurrence of the Closing for any reason other than failure to satisfy the
condition regarding the absence of injunctions and similar matters or the
termination of the Master Transaction Agreement pursuant to clause (a) or clause
(d) under 'Termination', (ii) prior to such date as is 180 days after such
termination there shall occur a Change of Control of a party or a party shall
enter into a definitive agreement providing for, or shall publicly announce its
intention to effect, any transaction involving a Change of Control of such party
or involving the sale or other disposition of all or substantially all of the
Contributed Business of such party (including by transfer to a joint venture or
similar arrangement) to or with an unaffiliated person or a tender offer or
exchange offer shall have been commenced or publicly announced that, if
consummated, would have the effect with respect to a party described in clause
(c) of the definition of 'Change of Control' and (iii) no fee has previously
been paid by such party pursuant to the foregoing
 
                                       59
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paragraphs, then upon (and subject to) the occurrence of such Change of Control
or the consummation of such transaction, such party will pay to the other party
a fee of $40 million; provided, however; that such fee shall instead be $10
million if the Master Transaction Agreement is terminated pursuant to clause
(xii) under 'Termination' because of the failure of the stockholders of such
party to approve the transfer of such party's Contributed Business and, at or
prior to the time of such stockholder vote, (1) there had been no public
disclosure or announcement by any person of (x) any such Change of Control,
definitive agreement, intention or transaction regarding such party or (y) any
Alternative Proposal that has been made to such party and (2) the Board of
Directors of such party had not withdrawn or adversely modified or taken a
public position materially inconsistent with its approval or recommendation to
the stockholders of such party of the transfer of such party's Contributed
Business contemplated hereby. See ' -- Termination.'
 
EXPENSES
 
     Subject to certain exceptions, all reasonable out-of-pocket costs, fees and
expenses incurred at any time by Lyondell or Millennium in connection with the
negotiation, execution and delivery of the Master Transaction Agreement and the
consummation of the transactions contemplated thereby shall be reimbursed by the
Partnership or shall be shared by Lyondell and Millennium pro rata in accordance
with the relative interests of their subsidiaries in the Partnership. However,
Lyondell and Millennium shall be solely responsible for and bear all of their
own respective costs, fees and expenses if the Master Transaction Agreement is
terminated and the Closing does not occur.
 
AMENDMENT AND WAIVER
 
     All waivers, modifications, amendments or alterations of the Master
Transaction Agreement shall require the written approval of each of Lyondell and
Millennium. The waiver by Lyondell or Millennium of a breach of any provision of
the Master Transaction Agreement shall not operate or be construed as a waiver
of any subsequent breach.
 
                       THE ASSET CONTRIBUTION AGREEMENTS
 
     The following is a summary of the material provisions of the Asset
Contribution Agreements between Lyondell and the Partnership and between
Millennium Petrochemicals and the Partnership, the form of which has been filed
with the SEC and is incorporated herein by reference. This summary is qualified
in its entirety by reference to the full and complete text of the form of the
Asset Contribution Agreements. All holders of Lyondell Common Stock and
Millennium Common Stock are encouraged to read the form of the Asset
Contribution Agreements carefully. See 'Where You Can Find More Information.'
 
     Notwithstanding the assumption of certain liabilities and obligations by
the Partnership (see ' -- Assumed Liabilities' below), Lyondell and Millennium
Petrochemicals may by law or agreement continue as the primary obligor of
certain of these liabilities. Although the Partnership will indemnify each of
Lyondell and Millennium Petrochemicals, and their respective affiliates, for the
liabilities assumed by the Partnership (see ' -- Indemnification' below),
Lyondell or Millennium Petrochemicals could be liable with respect to any such
liabilities if the Partnership is unable to satisfy its indemnification
obligations.
 
CONTRIBUTED ASSETS
 
     Each Contributor (i.e., Lyondell or Millennium Petrochemicals, a
wholly-owned subsidiary of Millennium), shall contribute to its Contributing
Partner (i.e., Lyondell LP for Lyondell and Millennium LP for Millennium
Petrochemicals), and its Contributing Partner shall cause to be contributed to
the Partnership, all of the assets, rights and properties (its 'Assets') used or
held for use in the contemplated operation and conduct of its Contributed
Business, other than the Excluded Assets.
 
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In each case, the Contributed Business will be the business described herein
under 'Businesses to be Contributed to the Partnership.' Lyondell will, among
other things, contribute its Accounts Receivable relating to the Contributed
Business and will buy back from the Partnership any such Accounts Receivable
that the Partnership has not collected within 180 days after the Closing Date.
 
EXCLUDED ASSETS
 
     The Assets contributed to the Partnership by Lyondell and Millennium
Petrochemicals shall not include the following: (i) cash and cash equivalents;
(ii) except for certain aspects of an employee benefit plan of Millennium
Petrochemicals and certain other employee matters of Lyondell or Millennium
Petrochemicals, any assets of any qualified or non-qualified pension or welfare
plans or other deferred compensation arrangements maintained by Contributor or
any affiliate thereof for employees of that Contributor or any affiliate thereof
prior to the Closing Date; (iii) Contributor's or any affiliate's right, title
and interest in and to (a) certain names and logos and any other statutory
names, trade names or trademarks, indications or descriptions of which such
names or any name similar thereto forms a part and (b) any other trade names,
trademarks, trademark registrations or trademark applications, copyrights,
copyright applications or copyright registrations or any derivative thereof or
design used in connection therewith that are not used principally in the normal
operation and conduct of and are not uniquely applicable to a Contributed
Business; (iv) all claims and rights against third parties (including, without
limitation, insurance carriers, indemnitors, suppliers and service providers),
to the extent they do not relate to Assumed Liabilities (as defined below); (v)
claims for refunds of taxes for time periods ending on or before the Closing
Date; (vi) subject to a technology license and trademark license to be granted
to the Partnership at Closing, any and all of the intellectual property and
trademarks of a Contributor or any affiliate thereof to the extent not used
principally in the normal operation and conduct of or to the extent not
applicable to a Contributed Business; (vii) all items sold in the ordinary
course of business prior to the Closing Date, none of which individually or in
the aggregate are material to the normal operation and conduct of a Contributed
Business; and (viii) certain tangible assets, intangible assets, real
properties, contracts and rights. In addition, Millennium Petrochemicals will
not contribute its accounts receivable. See ' -- Covenants Subsequent to Closing
Date.'
 
ASSUMED LIABILITIES
 
     On the Closing Date, the debts, liabilities and obligations of each
Contributor and any subsidiaries that it is contributing to the Partnership (its
'Contributed Subsidiaries') set forth below (the 'Assumed Liabilities') shall be
assumed by its Contributing Partner in connection with the transfer of Assets to
it and shall next be assumed by the Partnership in connection with the transfer
of Assets to it, and the Partnership shall agree to pay, perform and discharge
all such debts, liabilities and obligations when due: (i) all obligations
arising after the Closing Date under the contracts and leases that are assigned
to the Partnership, unless and to the extent that such obligations arises out of
a violation of such contract or lease prior to the Closing Date; (ii) all
obligations under purchase orders accepted by a Contributor or its Contributed
Subsidiaries in the ordinary course of business of its Contributed Business
prior to the Closing Date that are not filled as of the Closing Date; (iii)
certain current accrued expenses related to accrued vacation and, with respect
to the Millennium Contributed Business, the current portion of deferred
maintenance; (iv) all obligations and liabilities, of every kind and nature,
without limitation, arising out of, in connection with or related to the
ownership, operation or use after the Closing Date of the Assets or a
Contributed Business; (v) third party claims that are related to certain
pre-Closing contingent liabilities that are asserted prior to or within seven
years after the Closing Date, to the extent the aggregate thereof does not
exceed $7,000,000; (vi) third party claims that are related to pre-Closing
contingent liabilities and that are asserted seven years or more after the
Closing Date; (vii) certain obligations for indebtedness; (viii) for Millennium
Petrochemicals, all liabilities associated with a certain employee benefit plan
(the 'Assumed Plan'); (ix) all liabilities associated with products sold after
the Closing Date regardless of when manufactured; (x) certain long-term
liabilities and (xi) any other
 
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liability specifically assumed by the Partnership pursuant to the terms of the
Asset Contribution Agreements.
 
EXCLUDED LIABILITIES
 
     Except as otherwise expressly provided in the Asset Contribution Agreements
or the Assumption Agreement, the Partnership is assuming only the Assumed
Liabilities and is not assuming any other liability or obligation of a
Contributor or any affiliate thereof. All liabilities and obligations of a
Contributor and any affiliate thereof that are not Assumed Liabilities shall be
retained by and remain obligations and liabilities of that Contributor or such
affiliate (all such liabilities and obligations being herein referred to as the
'Excluded Liabilities'), including the following: (i) any pre-Closing contingent
liability that is not an Assumed Liability; (ii) any obligation or liability
relating to Excluded Assets; (iii) any obligation (a) for the payment of
severance benefits to employees of a Contributor or any affiliates except
certain employee matters, or (b) attributable to a Contributor's or any
affiliate's employment of any employee, agent or independent contractor prior to
the Closing Date; and (iv) current trade accounts payable and current accrued
expenses, other than those related to accrued vacation.
 
COVENANTS SUBSEQUENT TO CLOSING DATE
 
     Following the Closing Date, the Partnership shall afford, and will cause
its affiliates to afford, to each Contributor, their counsel, accountants and
other authorized representatives, during normal business hours, reasonable
access to the books, records and other data of their respective Contributed
Businesses with respect to the period prior to the Closing Date to the extent
that such access may be reasonably required by that Contributor.
 
     Except for certain exceptions, after the Closing Date the Partnership shall
be permitted to use any items of inventory or packaging material, any sales or
promotional materials, any forms or documents or any other printed material that
bear any of the names, including 'Lyondell' for Lyondell and 'Millennium', 'USI'
or 'Quantum' for Millennium, or other statutory names, trade names or
trademarks, indications or descriptions of which such names or any name similar
thereto forms a part until the earlier to occur of (i) such time as inventory of
such materials existing as of the Closing Date is used, or (ii) two years after
the Closing Date.
 
     Not later than 60 days after the Closing Date, Lyondell shall cause Coopers
& Lybrand L.L.P. to prepare and deliver to Lyondell and the Partnership, and
Millennium shall cause Price Waterhouse LLP to prepare and deliver to Millennium
and the Partnership, an audited balance sheet of its respective Contributed
Business as of the Closing Date (the 'Closing Date Balance Sheet').
 
     The Contributors will retain all current trade accounts payable and current
accrued expenses other than those related to employee vacation accruals. The
Partnership has agreed to pay such amounts on behalf of the Contributors on a
timely basis. As soon as practicable following the end of each month after which
such accounts payable are paid by the Partnership, but in any event within 15
days after the end of such month, each Contributor will reimburse the
Partnership for such payments attributable to its Contributed Business.
 
     The Partnership, as collecting agent for Lyondell, shall take all
commercially reasonable efforts to collect Lyondell's accounts receivable;
however, to the extent any such accounts receivable set forth on the Closing
Date Balance Sheet are not collected within 180 days after the Closing Date by
the Partnership, Lyondell will buy such uncollected accounts receivable from the
Partnership at the amount set forth on the Closing Date Balance Sheet.
 
     For Millennium Petrochemicals, the Partnership shall take all commercially
reasonable efforts to collect Millennium Petrochemicals's accounts receivable.
As soon as practicable after such Accounts Receivable are collected, but in any
event within fifteen days after the end of each month, the Partnership shall
remit such collections to Millennium Petrochemicals. If the accounts receivable
as of the Closing Date as set forth in the Closing Date Balance Sheet (the
'Confirmed Accounts
 
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Receivable') are less than $250 million, then in addition to the foregoing, the
Partnership shall pay Millennium Petrochemicals the difference between $250
million and the Confirmed Accounts Receivable within 10 days after the receipt
of the Closing Date Balance Sheet. If the Confirmed Accounts Receivable are more
than $250 million, Millennium Petrochemicals shall pay the Partnership the
difference between $250 million and the Confirmed Accounts Receivable.
 
     The Partnership and each Contributor acknowledge that the prepaid expenses
attributable to the Contributed Businesses will be conveyed to the Partnership
solely in order to facilitate the timely and efficient transfer of the
Contributed Businesses to the Partnership. Consequently, the Partnership shall
reimburse each Contributor for the prepaid expenses associated with its
respective Contributed Business (other than the prepaid expenses for
'turnaround' costs) within 10 days following the receipt of the Closing Date
Balance Sheet.
 
INDEMNIFICATION
 
     Subject to the following terms, each Contributor will agree, to the fullest
extent permitted by applicable law, to indemnify, defend and hold harmless the
Partnership and its affiliates and their respective officers, directors and
employees from, against and in respect of any liabilities incurred or suffered
by the Partnership or any of its affiliates, arising out of, in connection with
or relating to: (i) any misrepresentation in or breach of the representations
and warranties of a Contributor or any of its affiliates in the Asset
Contribution Agreements, the Assignment and Assumption Agreements, the Licenses,
or the Master Transaction Agreement; (ii) any failure of a Contributor or any of
its affiliates to perform any of its covenants or obligations contained in the
Asset Contribution Agreements, the assignment and assumption agreements, the
licenses, or the Master Transaction Agreement; (iii) Excluded Liabilities; (iv)
any pre-Closing contingent liability that is not an Assumed Liability; or (v)
for Lyondell, any action by Lyondell or its affiliates that results in the
occurrence of a 'Designated Event' as such term is defined in Lyondell's or its
affiliates' 1989 Indenture and Medium Term Notes but only to the extent that the
Partnership incurs an economic loss directly as a result of the occurrence of
the 'Designated Event' and in such case Lyondell's or its affiliates'
indemnification obligation is limited to the amount of such economic loss;
provided, however, that the following limitations shall apply to each
Contributor's indemnification obligations in clauses (i) and (iv) above: (a)
each Contributor shall not have any indemnification obligation under clause (i)
and (iv) above for any individual liability unless the amount of such liability
exceeds $25,000 (the 'Individual Basket'), but if the amount of such liability
exceeds the Individual Basket, the entire amount of such liability, including
the first $25,000 of such liability, may be the subject of indemnification; and
(b) to the extent any misrepresentation in or breach of the representations and
warranties of a Contributor results in a liability of the Partnership in excess
of the Individual Basket and such Liability would also constitute a pre-Closing
contingent liability, such misrepresentations or breach shall be treated as a
pre-Closing contingent liability.
 
     Notwithstanding any other provision of each Asset Contribution Agreement,
to the fullest extent permitted by law, neither one of the Contributors nor any
of their agents, employees, representatives or affiliates shall be liable for
consequential, incidental, indirect or punitive damages in connection with
direct claims by the Partnership (i.e., a claim by the Partnership that does not
seek reimbursement for a third party claim paid or payable by the Partnership)
with respect to its indemnification obligations under each Asset Contribution
Agreement unless any such claim arises out of the fraudulent actions of that
Contributor. In determining the amount of any loss, liability, or expense for
which the Partnership is entitled to indemnification under each Asset
Contribution Agreement, the gross amount thereof will be reduced (but not below
zero) by the net present value of any correlative insurance proceeds actually
realized by the Partnership under policies to the extent that the future premium
rate will not be increased by claim experience.
 
     Notwithstanding the provisions of paragraphs (i) and (iv) of the preceding
paragraph, it is expressly agreed that each Contributor shall not be required to
indemnify the Partnership for any Liability arising out of, in connection with
or related to any HSE Claim to the extent that the condition, event,
circumstance or other basis for the HSE Claim was exacerbated or accelerated by
the Partnership.
 
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     'HSE Claim' means (i) any actions, events, circumstances or
responsibilities (including compliance actions or requirements) that are
necessary to comply with HSE Laws but only to the extent that any of the
foregoing give rise to out of pocket costs or expenses or result in a liability
that is required by GAAP to be reflected on the balance sheet of the applicable
party or (ii) any third party (including private parties, authorities and
employees acting on each such party's own behalf or on the behalf of other third
parties) actions, lawsuits, claims, investigations or proceedings arising under
HSE Laws. 'HSE Laws' means any legal requirements or rule of common law now in
effect (including any amendments now in effect) and any current judicial or
administrative interpretation thereof, including any judicial or administrative
order, consent decree, or judgment, relating to (i) any ambient air, surface
water, drinking water, groundwater, land surface, subsurface strata, river
sediment, natural resources or real property and the physical buildings,
structures and fixtures thereon, including sewer, septic and waste treatment,
storage or disposal systems (the 'Environment'), including pollution,
contamination, cleanup, preservation, protection and reclamation of the
Environment; (ii) health or safety, including the exposure of employees and
other persons to any chemical substance; (iii) the release or threatened release
of any chemical substance, noxious noise or odor, including investigation,
study, assessment, testing, monitoring, containment, removal, remediation,
response, cleanup and abatement of such release or threatened release; and (iv)
the management of any chemical substance, including the manufacture, generation,
formulation, processing, labeling, use, treatment, handling, storage, disposal,
transportation, distribution, re-use, recycling or reclamation of any chemical
substance.
 
     Subject to the other indemnification provisions of the Asset Contribution
Agreement, the Partnership also will indemnify, to the fullest extent permitted
by law, each Contributor and its affiliates against and agrees to hold each of
them harmless from any and all liability incurred or suffered by them arising
out of or relating to: (i) any misrepresentation in or breach of the
representations and warranties of the Partnership or the failure of the
Partnership to perform any of its covenants or obligations contained in the
Asset Contribution Agreements, the assignment and assumption agreements or the
licenses; (ii) Assumed Liabilities; or (iii) any HSE Claim to the extent arising
out of the Partnership's exacerbation or acceleration of such HSE Claim.
 
     Notwithstanding any other provision of the Asset Contribution Agreements,
to the fullest extent permitted by law, neither the Partnership nor any of its
agents, employees, representatives or affiliates shall be liable for
consequential, incidental, indirect or punitive damages in connection with
direct claims by the Contributors with respect to their indemnification
obligations under the Asset Contribution Agreements unless any such claim arises
out of the fraudulent actions of the Partnership. In determining the amount of
any loss, liability, or expense for which a Contributor is entitled to
indemnification under its Asset Contribution Agreement, the gross amount thereof
will be reduced (but not below zero) by the net present value of any correlative
insurance proceeds actually realized by that Contributor under policies to the
extent the future premium rate will not be increased by claim experience.
 
     The rights provided to the Partnership shall be the Partnership's sole
remedy for breach of representation and warranty by or covenant or obligation of
the Contributors under the Asset Contribution Agreements, the assignment and
assumption agreements and the licenses. The rights provided to the Contributors
shall be the Contributors' sole remedy for breach of representation and warranty
by or covenant of obligation of the Partnership under the Asset Contribution
Agreements, the assignment and assumption agreements and the licenses.
 
     Without limiting or enlarging the scope of the indemnification, release and
assumption obligations set forth in the Asset Contribution Agreements, to the
fullest extent permitted by law, an indemnified party shall be entitled to
indemnification, regardless of whether the indemnifiable loss giving rise to any
such indemnification obligation is the result of the sole, gross, active,
passive, concurrent or comparative negligence, strict liability or other fault
or violation of any law of or by any such indemnified party.
 
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PAYMENT OF CERTAIN EXPENSES AND TAXES
 
     Subject to the following provisions, each Contributor shall be responsible
for all taxes attributable to that Contributor's ownership or use of the Assets
or operation of its Contributed Business prior to the Closing and the
Partnership shall be responsible for all taxes attributable to the Partnership's
ownership or use of the Assets or operation of those Contributed Businesses
after the Closing Date. Each Contributor shall be responsible for any liability
of the Partnership pursuant to Texas Tax Code Section 111.020 with respect to
any amounts owed or owing by such Contributor under Title 2, Texas Tax Code. All
sales, transfer, or other similar taxes incurred in connection with the transfer
of the Assets shall be borne by the Partnership. All real property taxes,
personal property taxes, ad valorem taxes, and other similar taxes (or payments
in lieu of such taxes) assessed on any of the Assets in the tax period in which
the Closing Date occurs (other than the Inventory Taxes defined below) shall be
prorated between the Partnership and the appropriate Contributor as of the
Closing. All real property taxes, personal property taxes, ad valorem taxes, and
other similar taxes (or payments in lieu of such taxes) assessed on the
inventory in the tax period in which the Closing Date occurs ('Inventory Tax')
shall be payable by the Contributor. The Partnership shall pay any title or
recordation fees in connection with the transfer of the Assets. The Partnership
shall also pay for any title insurance policies or surveys of the fee interests
that are requested or ordered by the Partnership.
 
                           THE PARTNERSHIP AGREEMENT
 
     The following is a summary of the material provisions of the Partnership
Agreement, which has been filed with the SEC and is incorporated herein by
reference. This summary is qualified in its entirety by reference to the full
and complete text of the Partnership Agreement. All holders of Lyondell Common
Stock and Millennium Common Stock are encouraged to read the Partnership
Agreement carefully and in its entirety. See 'Where You Can Find More
Information.'
 
GENERAL
 
     Lyondell GP, Lyondell LP, Millennium GP and Millennium LP entered into the
Partnership Agreement on                , 1997. The Partnership Agreement will
govern the Partnership, which is a Delaware limited partnership named
                         Company, L.P. The Partnership will continue in
existence until its dissolution in accordance with the Partnership Agreement.
See ' -- Dissolution.' The two General Partners of the Partnership will be
Lyondell GP and Millennium GP. Lyondell GP is a direct wholly-owned subsidiary
of Lyondell, and Millennium GP is an indirect wholly-owned subsidiary of
Millennium.
 
GOVERNANCE
 
     The General Partners have established a partnership governance committee
(the 'Partnership Governance Committee') to manage and control the business,
property and affairs of the Partnership, including the determination and
implementation of the Partnership's strategic direction. The General Partner
will exercise their authority to manage and control the Partnership only through
the Partnership Governance Committee. The Partnership Governance Committee
consists of six members (the 'Representatives'), three of whom are
representatives of Lyondell GP and three of whom are representatives of
Millennium GP. Each General Partner will also designate alternate
Representatives who will be authorized to participate in the Partnership
Governance Committee in place of any Representatives who are absent from a
meeting. The Partnership Governance Committee has two co-chairs, and Lyondell
and Millennium have each appointed one of such co-chairs. The Partnership
Governance Committee shall hold regular meetings at such times and at such
places as shall be from time to time determined in advance by the Partnership
Governance Committee, and any Representative may call a special meeting of the
Partnership Governance Committee at any time.
 
     In general, the approval of two or more Representatives acting for Lyondell
GP will be necessary and sufficient for the Partnership Governance Committee to
take any action; however, the Partnership
 
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Governance Committee may not take certain actions unless they are approved by
two Representatives of Lyondell GP and two Representatives of Millennium GP, as
described below. See ' -- Unanimous Voting Requirements.' This means, in effect,
that Lyondell's Representatives will control the Partnership Governance
Committee (and, as a result, the Partnership) except where the approval of
Millennium's Representatives is required. Even though ordinary actions by the
Partnership Governance Committee may be approved by two Representatives of
Lyondell GP, the Partnership Governance Committee may not take any action at a
meeting with respect to any matter that was not reflected on an agenda that was
properly delivered to all of the Representatives in advance, unless at least one
of Millennium GP's Representatives is present. The participation rights of
either General Partner's Representatives may be curtailed to the extent that
such General Partner or its affiliates causes a default under the Partnership
Agreement. See ' -- Default.'
 
     From time to time, the Partnership Governance Committee may designate one
or more auxiliary committees ('Auxiliary Committees') or disband any Auxiliary
Committee. Each Auxiliary Committee shall have an equal number of members
appointed by Lyondell GP and Millennium GP, respectively. Auxiliary Committees
may exercise specific authority delegated to them by the Partnership Governance
Committee, consistent with the requirements that certain actions require the
approval of at least two Representatives from each of Lyondell GP and Millennium
GP.
 
     The initial members of the Partnership Governance Committee are: Dan F.
Smith, President and Chief Executive Officer of Lyondell and Chief Executive
Officer ('CEO') of the Partnership (co-chairman of the Partnership Governance
Committee); William M. Landuyt, Chairman and Chief Executive Officer of
Millennium (co-chairman of the Partnership Governance Committee); Clifton B.
Currin, Jr., Vice President, Corporate Development of Lyondell; John E.
Lushefski, Senior Vice President and Chief Financial Officer of Millennium;
Jeffrey R. Pendergraft, Senior Vice President, Chief Administrative Officer of
Lyondell; and Dr. Ronald H. Yocum, President and Chief Executive Officer of
Millennium Petrochemicals.
 
     No Representative or Alternate of a partner who, as an officer, director or
employee of such partner or any of its Affiliates, participates in material
operational decisions by such Partner or Affiliate regarding a business or
operation of such partner or affiliate that competes with a business or
operation of the Partnership or of the other partner or its affiliates, or that
competes with a Business Opportunity shall receive or have access to any
competitively sensitive information regarding the competing business of the
Partnership or of the other partner or its affiliates or such Business
Opportunity, nor shall such Representative or affiliate participate in any
decision of the Partnership Governance Committee relating to such business or
operation of the Partnership or the other partner or its affiliates or such
Business Opportunity.
 
UNANIMOUS VOTING REQUIREMENTS
 
     Unless approved by two or more Representatives of each of Lyondell GP and
Millennium GP, the Partnership Governance Committee may not directly or
indirectly take (or commit to take), and none of the Partnership, any subsidiary
thereof or any person acting in the name of or on behalf of any of them,
directly or indirectly, may take or commit to take any of the following actions
(whether in a single transaction or a series of related transactions): (i) to
cause the Partnership, directly or indirectly, to engage, participate or invest
in any business outside the scope of its business as described in the
Partnership Agreement; (ii) to approve any Strategic Plan, as well as any
amendments or updates thereto (including the annual update described under
' -- Strategic Plans and Annual Budgets; Expenses' below); (iii) to authorize
any disposition of assets having a fair market value exceeding $30 million in
any one transaction or a series of related transactions not contemplated in an
approved Strategic Plan; (iv) to authorize any acquisition of assets or any
capital expenditure exceeding $30 million that is not contemplated in an
approved Strategic Plan; (v) to require capital contributions to the Partnership
(other than contributions contemplated by the Asset Contribution Agreements or
an approved Strategic Plan or to achieve or maintain compliance with certain
laws) within any fiscal year if the total of such contributions required from
the partners within that year would exceed $100 million or the total of such
contributions required from the partners within that year and the immediately
 
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preceding four years would exceed $300 million; (vi) to authorize the incurrence
of debt for borrowed money unless (a) such debt is contemplated by clause (vii)
below, (b) after giving effect to the incurrence of such debt (and any related
transactions) the Partnership would be expected to have an 'investment grade'
debt rating by Moody's Investor Services Inc. and Standard & Poor's Corporation
or (c) such debt is incurred to refinance the public or bank debt assumed or
incurred by the Partnership as contemplated by the Master Transaction Agreement
or to refinance any such refinancing debt, and in the case of each of (b) and
(c), the agreement relating to such debt does not provide that the Transfer by a
partner of its units (or a change of control with respect to any partner or any
of its affiliates) would constitute a default thereunder, otherwise accelerate
the maturity thereof or give the lender or holder any 'put rights' or similar
rights with respect thereto; (vii) to make borrowings under the Partnership's
working capital facility and/or its uncommitted lines of credit at any time if
the aggregate principal amount of such borrowings outstanding at such time would
exceed $250 million; (viii) to enter into interest rate protection or other
hedging agreements (other than hydrocarbon hedging agreements in the ordinary
course); (ix) to enter into any capitalized lease or off-balance sheet financing
arrangements involving payments (individually or in the aggregate) by it in
excess of $30 million in any fiscal year; (x) to cause the Partnership or any
subsidiary of the Partnership to issue, sell, redeem or acquire any units of the
Partnership or other equity securities (or any rights to acquire, or any
securities convertible into or exchangeable for, Partnership units or other
equity securities); (xi) to make Partnership cash distributions in excess of
Available Net Operating Cash (as defined below) or to make non-cash
distributions (except as provided in the Partnership Agreement in respect of a
dissolution or liquidation); (xii) to appoint or discharge executive officers
(other than the CEO), based on the recommendation of the CEO; (xiii) to approve
material compensation and benefit plans and policies, material employee policies
and material collective bargaining agreements for the Partnership's employees;
(xiv) to initiate or settle any litigation or governmental proceedings if the
effect thereof would be material to the financial condition of the Partnership;
(xv) to change the independent accountants for the Partnership; (xvi) to change
the Partnership's method of accounting as adopted in accordance with the
Partnership Agreement or to make certain tax elections referred to in the
Partnership Agreement; (xvii) to create or change the authority of any Auxiliary
Committee; (xviii) to merge, consolidate or convert the Partnership or any
subsidiary thereof with or into any other entity (other than a wholly owned
subsidiary of the Partnership); (xix) to file a petition in bankruptcy or
seeking any reorganization, liquidation or similar relief on behalf of the
Partnership or any subsidiary; or to consent to the filing of a petition in
bankruptcy against the Partnership or any subsidiary; or to consent to the
appointment of a receiver, custodian, liquidator or trustee for the Partnership
or any subsidiary or for all or any substantial portion of their property; and
(xx) to exercise any of the powers or rights described below with respect to a
Conflict Circumstance (as defined below) involving (a) LYONDELL-CITGO Refining,
its successors or assigns, (b) Lyondell Methanol, its successors or assigns or
(c) any other affiliate of either Lyondell GP or Millennium GP, if such
affiliate is not controlled by Lyondell or Millennium, respectively.
 
     Although unanimous approval by all six members of the Partnership
Governance Committee is never required, Lyondell and Millennium have referred to
the requirements described above as 'unanimous voting requirements' because two
representatives of each of the General Partners must agree on any action taken
in respect of the enumerated matters.
 
TRANSACTIONS WITH AFFILIATES
 
     In the event of any transaction or dealing between the Partnership (or any
subsidiaries), on the one hand, and a General Partner (or any of its
affiliates), on the other hand (a 'Conflict Circumstance'), the other General
Partner (the 'Nonconflicted General Partner') shall have sole and exclusive
power, at the expense of the Partnership, (i) to control all decisions,
elections, notifications, actions, exercises or nonexercises and waivers of all
rights, privileges and remedies provided to, or possessed by, the Partnership
with respect to such Conflict Circumstance and (ii) in the event of any
potential, threatened or asserted claim, dispute or action with respect to such
Conflict Circumstance, to retain and direct legal counsel and to control,
assert, enforce, defend, litigate, mediate, arbitrate, settle, compromise or
waive any and all such claims, disputes and actions. Accordingly, any action by
the Partnership Governance
 
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Committee with respect to a Conflict Circumstance shall require the approval of
at least two Representatives of the Nonconflicted General Partner. Each General
Partner, in exercising its control, power and rights with respect to Conflict
Circumstances has agreed to act in good faith and in a manner it believes to be
in the best interests of the Partnership. In any Conflict Circumstance, the
General Partner who is dealing with the Partnership (and its affiliates) shall
have the right to deal with the Partnership and with the Nonconflicted General
Partner on an arm's-length basis and in a manner it believes to be in its own
best interests, but in any event must deal with them in good faith.
 
OFFICERS
 
     The executive officers of the Partnership shall consist of a CEO, a
President and Chief Operating Officer and others as determined from time to time
by the Partnership Governance Committee. See 'Management of the Partnership.'
Except for the CEO, the approval of at least two Representatives of each of
Lyondell GP and Millennium GP is required to appoint or discharge executive
officers, based upon the recommendation of the CEO; however, either Lyondell GP
or Millennium GP may, by action of two or more of its Representatives, remove
from office any executive officer of the Partnership, including the CEO, who
takes or causes the Partnership to take, any action described above under ' --
Unanimous Voting Requirements' without the required approval of two or more
Representatives of each of Lyondell GP and Millennium GP.
 
     The CEO shall hold office for a five-year term, subject to the CEO's
earlier death, resignation or removal. Upon the expiration of such term or
earlier vacancy, Lyondell GP shall designate the CEO, provided that such person
shall be reasonably acceptable to Millennium GP. The CEO shall not be required
to be an employee of the Partnership. The CEO may be removed at any time by
action of the Partnership Governance Committee, meaning that the approval of two
Representatives of Lyondell GP is required.
 
     The CEO of the Partnership shall have general authority and discretion
comparable to that of a chief executive officer of a publicly held Delaware
corporation of similar size to direct and control the business and affairs of
the Partnership, including without limitation its day-to-day operations in a
manner consistent with the Annual Budget and the most recently approved
Strategic Plan. The CEO shall take steps to implement all orders and resolutions
of the Partnership Governance Committee or, as applicable, any Auxiliary
Committee. The CEO will also establish salaries or other compensation for the
other executive officers of the Partnership consistent with plans approved by
the Partnership Governance Committee. Except as approved by the Partnership
Governance Committee, all fees and compensation of the employees and officers of
the Partnership, other than the CEO, with respect to their services as such
officers and employees shall be payable solely by the Partnership.
 
STRATEGIC PLANS AND ANNUAL BUDGETS; EXPENSES
 
     The Partnership shall be managed in accordance with a five-year Strategic
Plan which shall be updated annually under the direction of the CEO and
presented for approval by the Partnership Governance Committee no later than 90
days prior to the start of the first fiscal year covered by the updated plan.
The Strategic Plan must be approved each year by at least two Representatives of
each of Lyondell GP and Millennium GP. The Strategic Plan shall establish the
strategic direction of the Partnership, including plans relating to capital
maintenance and enhancement, geographic expansion, acquisitions and
dispositions, new product lines, technology, long-term supply and customer
arrangements, internal and external financing, environmental and legal
compliance, and plans, programs and policies relating to compensation and
industrial relations. The Strategic Plan shall include projected income
statements, balance sheets and cash flow statements, including the expected
timing and amounts of capital contributions and cash distributions. The format
and level of detail of each Strategic Plan shall be consistent with that of the
initial Strategic Plan agreed to by Lyondell GP and Millennium GP on or prior to
the Closing Date or the Strategic Plan most recently approved by at least two
Representatives of each of Lyondell GP and Millennium GP.
 
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     In addition, the executive officers of the Partnership shall prepare an
Annual Budget for each fiscal year. Each Annual Budget will include an Operating
Budget and Capital Expenditure Budget, provided that each Annual Budget shall be
consistent with the information for such fiscal year included in the Strategic
Plan most recently approved by two Representatives of each of Lyondell GP and
Millennium GP. Unless otherwise provided in the most recently approved Strategic
Plan, each Annual Budget shall utilize a format and provide a level of detail
consistent with the Partnership's Annual Budget for the 1998 fiscal year.
 
     If for any fiscal year the Partnership Governance Committee has failed to
approve an updated Strategic Plan, then, subject to the provisions regarding
deadlock described below, for such year and each subsequent year prior to the
approval of an updated Strategic Plan, the executive officers of the Partnership
shall prepare the Annual Budget consistent with the projections and other
information for that year included in the Strategic Plan most recently approved
by two Representatives of each of Lyondell GP and Millennium GP; provided,
however, that the CEO, acting in good faith, shall be entitled to modify any
such Annual Budget in order to satisfy current contractual and compliance
obligations and to account for other changes in circumstances resulting from the
passage of time or the occurrence of events beyond the control of the
Partnership. The CEO shall not be authorized to cause the Partnership to proceed
with capital expenditures to accomplish capital enhancement projects except to
the extent that such expenditures would enable the Partnership to continue or
complete any such capital project reflected in the last Strategic Plan that was
approved by two Representatives of each of Lyondell GP and Millennium GP.
 
     If the Partnership Governance Committee has not agreed upon and approved an
updated Strategic Plan by such date as is 12 months after the beginning of the
first fiscal year that would have been covered by such plan, then Lyondell GP
and Millennium GP shall submit their disagreements to mediation by a neutral
third party (the 'Neutral'), who will be mutually agreed upon by the General
Partners (or by certain third parties if the General Partners cannot agree).
Within 20 days of selection of the Neutral, two persons having decision-making
authority on behalf of each General Partner shall meet with the Neutral and
agree upon procedures and a schedule for attempting to resolve the differences
between the General Partners. They shall continue to meet thereafter on a
regular basis until (i) agreement is reached by the General Partners (acting
through their Representatives) on an updated Strategic Plan or (ii) at least 24
months have elapsed since the beginning of the first fiscal year that was to be
covered by the first updated plan for which agreement was not reached and one
General Partner shall determine and notify the other General Partner and the
Neutral in writing that no agreement resolving the dispute is likely to be
reached. Following any such notice, either General Partner may elect to dissolve
the Partnership. See ' -- Dissolution and Termination.'
 
     Generally, all Partnership expenses (both operating and capital expenses),
regardless of whether included in any Strategic Plan or Annual Budget, shall be
funded from operating cash flows or authorized borrowings under available lines
of credit, unless otherwise agreed by the Partnership Governance Committee or,
in certain circumstances, determined by the CEO. See ' -- Capital
Contributions.' After a Strategic Plan and an Annual Budget have been approved
by the Partnership Governance Committee (or an Annual Budget has been developed
as described above in cases where an updated Strategic Plan has not yet been
approved), the CEO will be authorized, without further action by the Partnership
Governance Committee to cause the Partnership to make expenditures consistent
with such Strategic Plan and Annual Budget, provided that all internal control
policies and procedures, including those regarding the required authority for
certain expenditures, shall have been followed. In any emergency, the CEO or the
CEO's designee shall be authorized to take such actions and to make such
expenditures as may be reasonably necessary to react to the emergency regardless
of whether such expenditures have been included in an approved Strategic Plan or
Annual Budget. Promptly after learning of an emergency, the CEO or such designee
shall notify the Representatives of the nature of the emergency and the response
that has been made, or is committed or proposed to be made, with respect to the
emergency.
 
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DISTRIBUTION OF AVAILABLE NET OPERATING CASH
 
     Subject to applicable law, the Partnership will distribute to the partners,
as soon as practicable following the end of each month, all Available Net
Operating Cash, as defined in the Partnership Agreement. On a cumulative basis,
(i) distributions are to be made to the extent of cumulative Profits to the
partners in the ratio of the units owned by each partner to the total number of
units ('Pro Rata'), and (ii) the remaining distributions are to be made to the
Limited Partners Pro Rata. The initial Pro Rata interests of the Partners are as
follows: Lyondell GP, 1.14%; Lyondell LP, 55.86%; Millennium GP, 0.86% and
Millennium LP, 42.14%.
 
     Distributions to the partners of cash or property arising from a
liquidation of the Partnership shall be made in accordance with the capital
account balances of the partners.
 
     Any amount otherwise distributable to a partner as described above shall,
unless otherwise agreed by the Nonconflicted General Partner as described under
' -- Transactions with Affiliates' above, be applied by the Partnership to
satisfy any of the following obligations that are owed by such partner or its
affiliate to the Partnership and that are not paid when due: (i) in the case of
Lyondell LP, the failure to pay any interest or principal when due on the
Lyondell Note or, in the case of any partner, the failure to pay any interest or
principal when due on any indebtedness for borrowed money of such partner or any
affiliate of such partner to the Partnership; (ii) in the case of any partner,
the failure of such partner or any affiliate of such partner to make any
indemnification payment pursuant to its Asset Contribution Agreement that has
been finally determined to be due; and (iii) in the case of any partner, the
failure to make any capital contribution required pursuant to the Partnership
Agreement (other than pursuant to its Asset Contribution Agreement).
 
CAPITAL CONTRIBUTIONS
 
     Upon the formation of the Partnership, the partners will contribute an
aggregate of $1,000,000 in cash in exchange for an aggregate of 10,000 units. In
addition, on the Closing Date, the Limited Partners shall make the following
additional contributions: (i) pursuant to its Asset Contribution Agreement,
Lyondell LP will contribute, or cause to be contributed to the Partnership, the
assets contemplated thereby subject to the assumed liabilities contemplated
thereby and (ii) pursuant to its Asset Contribution Agreement, Millennium
Petrochemicals will contribute to the Partnership the assets contemplated
thereby subject to the assumed liabilities contemplated thereby. Simultaneously
with Millennium Petrochemicals' contribution, the Partnership will also repay
$750 million in intercompany indebtedness assumed from Millennium
Petrochemicals. Lyondell and Millennium intend that the contribution of assets
subject to liabilities will qualify as a tax-free contribution under Section 721
of the Internal Revenue Code in which no partner will recognize gain or loss.
The partners have agreed that the Partnership will so file its tax return, and
each partner has agreed to file its tax return on the same basis and to maintain
such position consistently at all times thereafter.
 
     Subject to the requirement that two Representatives of each of Lyondell GP
and Millennium GP must approve any capital contributions that would exceed a
total of $100 million in any fiscal year or a total of $300 million within any
five-year period, the Partnership Governance Committee, on behalf of the
Partnership, may issue a written notice to the Limited Partners calling for an
additional capital contribution to the Partnership. Any such additional
contributions will be apportioned among the Limited Partners Pro Rata, and the
capital contribution must be made within seven business days from the date the
funding notice is issued. In addition, subject to the limitation that the
approval of two Representatives of each of Lyondell GP and Millennium GP is
required for capital contributions in excess of a total of $100 million in any
fiscal year or a total of $300 million in any five-year period, the CEO may also
issue a funding notice to the Limited Partners, to the extent that he determines
at any time that funds are needed to fund the operations of the Partnership.
 
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DESCRIPTION OF PARTNERS
 
     Except as expressly set forth in the Partnership Agreement, each General
Partner has agreed to exercise its authority to manage and control the
Partnership only through action of the Partnership Governance Committee. No
General Partner has the authority, and each General Partner has agreed not to
exercise, or purport or attempt to exercise, any authority (i) to act for or
incur, create or assume any obligation, liability or responsibility on behalf of
the Partnership or any other partner, (ii) to execute any documents on behalf
of, or otherwise bind, or purport or attempt to bind, the Partnership, or (iii)
to otherwise transact any business in the name of the Partnership, in each case
except pursuant to action of the Partnership Governance Committee. No Limited
Partner shall take part in the management or control of the Partnership's
business, transact any business in the Partnership's name or have the power to
sign documents for or otherwise bind the Partnership.
 
     LYONDELL GP AND LYONDELL LP. Lyondell GP and Lyondell LP are corporations
which were incorporated in Delaware on                , 1997. Each of Lyondell
GP and Lyondell LP is a direct wholly-owned subsidiary of Lyondell. Lyondell GP
has no business or assets except for its ownership of general partner units in
the Partnership, and Lyondell LP has no business or assets except for its
ownership of limited partner units in the Partnership. In the Partnership
Agreement, Lyondell GP and Lyondell LP have each agreed that its business shall
be restricted solely to the holding of its units in the Partnership (and the
doing of things necessary or incidental in connection therewith), and that it
shall not own any assets, incur any liabilities or engage, participate or invest
in any business outside the scope of such business.
 
     MILLENNIUM GP AND MILLENNIUM LP. Millennium GP and Millennium LP are
limited liability companies which were organized in Delaware on
                 , 1997. Each of Millennium GP and Millennium LP is an indirect
wholly-owned subsidiary of Millennium. Millennium GP has no business or assets
except for its ownership of general partner units in the Partnership, and
Millennium LP has no business or assets except for its ownership of limited
partner units in the Partnership. In the Partnership Agreement, Millennium GP
and Millennium LP have each agreed that its business shall be restricted solely
to the holding of its units in the Partnership (and the doing of things
necessary or incidental in connection therewith), and that it shall not own any
assets, incur any liabilities or engage, participate or invest in any business
outside the scope of such business.
 
INDEMNIFICATION
 
     The Partnership will agree, to the fullest extent permitted by applicable
law, to indemnify, defend and hold harmless each partner, its affiliates and its
respective officers, directors and employees from, against and in respect of any
liability which such person may sustain, incur or assume as a result of, or
relative to, any third party claim arising out of or in connection with the
business, property or affairs of the Partnership, except to the extent that it
is finally determined that such third party claim arose out of or was related to
actions or omissions of the indemnified partner, its affiliates or any of their
respective officers, directors or employees (acting in their capacities as such)
constituting a breach of the Partnership Agreement or any Related Agreement (as
defined in the Master Transaction Agreement). This indemnification obligation is
not intended to, nor shall it, affect or take precedence over the indemnity
provisions contained in any Related Agreement.
 
PARTNERS' RIGHT OF CONTRIBUTION
 
     Each partner will agree, to the fullest extent permitted by law, to
indemnify, defend and hold harmless the other partners, their affiliates and
their respective officers, directors and employees from and against the
indemnifying partner's Pro Rata share (calculated at the time any such liability
was incurred) of any liability that such indemnified person may sustain, incur
or assume as a result of or relating to any third party claim arising out of or
in connection with the business, property or affairs of the Partnership;
provided, however, that no such persons shall be entitled to indemnity to the
extent it is finally determined that such third party claim arose out of or was
related to actions or omissions of the indemnified partner, its affiliates or
any of their respective officers, directors or employees (acting in
 
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their capacity as such) constituting a breach of the Partnership Agreement or
Related Agreement. In addition, no such person shall be entitled to the
indemnity described in this paragraph unless (i) such person first makes a
written demand for indemnification from the Partnership for indemnification and
the Partnership shall fail to satisfy such demand in a manner reasonably
satisfactory to the demanding person within 60 days of such notice or (ii) the
Partnership is insolvent or otherwise unable to satisfy its obligations.
 
TRANSFERS AND PLEDGES
 
     Without the consent of the Partnership Governance Committee, no partner may
transfer less than all of its units of interest in the Partnership. If any
Limited Partner and its affiliated General Partner desire to transfer (pursuant
to a cash sale) all of their units (together, the 'Selling Partners'), they must
give written notice (the 'Initial Notice') to the Partnership and the other
Partners (the 'Offeree Partners') stating the Selling Partners desire to
transfer their units and stating the cash purchase price and all other terms on
which they are willing to sell (the 'Offer Terms'). Delivery of an Initial
Notice shall constitute the irrevocable offer of the Selling Partners to sell
their units to the Offeree Partners. The Offeree Partners shall have the option,
exercisable by delivering written notice (the 'Acceptance Notice') of such
exercise to the Selling Partners within 45 days of the date of Initial Notice,
to elect to purchase all of the units of the Selling Partners on the Offer Terms
described in the Initial Notice. The Acceptance Notice shall set a date for
closing the purchase, such date to be not less than 30 nor more than 90 days
after delivery of the Acceptance Notice, subject to extension in certain
circumstances. The purchase price for the Selling Partners' units shall be paid
in cash delivered at the closing.
 
     If the Offeree Partners do not elect to purchase the Selling Partners'
units within 45 days after the receipt of the Initial Notice, the Selling
Partners shall have a further 180 days during which they may, subject to certain
conditions described below, consummate the sale of their units to a third party
purchaser at a purchase price and on such other terms that are no more favorable
to the purchaser than the Offer Terms. If the sale is not completed within such
180-day period, the Initial Notice shall be deemed to have expired and a new
notice and offer shall be required before the Selling Partners may make any
transfer of their units.
 
     Before the Selling Partners may consummate a transfer of their units to a
third party in accordance with the Partnership Agreement, the Selling Partners
shall demonstrate to the Partnership that the person willing to serve as the
proposed purchaser's guarantor (under an agreement substantially similar to the
Parent Agreement) has outstanding indebtedness that is rated investment grade by
Moody's Investors Service, Inc. and Standard & Poor's Corporation (or where such
person has no rated indebtedness outstanding, such person shall provide an
opinion from an nationally recognized investment banking firm that such person
could be reasonably expected to obtain such ratings). In addition, a partner may
transfer its units only if certain events occur, including (i) the transfer is
accomplished in a non-public offering in compliance with, and exempt from, the
registration and qualification requirements of all federal and state securities
laws and regulations, (ii) the transfer does not cause a default under any
material contract to which the Partnership is a party or by which the
Partnership or any of its properties is bound, (iii) the transferee executes an
appropriate agreement to be bound by the Partnership Agreement, (iv) the
transferor and/or transferee bears all reasonable costs incurred by the
Partnership in connection with the transfer, (v) the business and activities of
the transferee comply with certain covenants set forth in Section 9.6 of the
Partnership Agreement, (vi) the guarantor of the transferee satisfies the rating
agency criteria described above and delivers an agreement to the ultimate parent
entity of the Offeree Partners and to the Partnership substantially in the form
of the Parent Agreement, (vii) neither of the partners wishing to transfer their
units is in default in the timely performance of any of its material obligations
to the Partnership and (viii) simultaneously with the transfer of units by a
Limited Partner, the units held by its affiliated General Partner are
simultaneously transferred to such person or a wholly-owned affiliate of such
person, and vice versa.
 
     Notwithstanding the above, without the need for the consent of any person,
any partner may transfer its units to any wholly-owned affiliate of such
partner, provided that the transferee executes an
 
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instrument reasonably satisfactory to the Partnership Governance Committee
accepting the terms and provisions of the Partnership Agreement. In addition,
either Limited Partner may, at its option, at any time and without the need for
the consent of any person, convert up to 99% of its limited partner units in the
Partnership to general partner units by transferring such units to its
affiliated General Partner. The partners have agreed that in such event the
Partnership Agreement will be amended so that Lyondell and Millennium will
maintain their respective rights in the Partnership following any such
conversion.
 
     A partner shall not in any transaction or series of actions, directly or
indirectly pledge all or any part of its units or interest in the Partnership.
However, a partner may at any time assign its right to receive distributions
from the Partnership so long as such assignment does not purport to assign any
right of such partner to participate in or manage the affairs of the
Partnership, to receive any information or accounting of the affairs of the
Partnership, or to inspect the books or records of the Partnership or any other
right of a partner pursuant to the Partnership Agreement or the Delaware Revised
Uniform Limited Partnership Act. In addition, subject to any restrictions
imposed by the Parent Agreement, nothing in the Partnership Agreement shall
prevent the transfer or pledge by the owner thereof of any capital stock, equity
ownership interests or other security of the partner or any affiliate of a
partner.
 
DEFAULT
 
     Each of the following events shall constitute a 'Default' and create the
rights provided for below in favor of the Partnership and the partners not in
default ('Non-Defaulting Partners') against the partners in default ('Defaulting
Partners') (i) the failure by a partner to make any contribution to the
Partnership as required pursuant to the Partnership Agreement (other than
pursuant to the Asset Contribution Agreement), which failure continues for at
least five business days from the date that the partner is notified such
contribution is overdue; (ii) in the case of each of Lyondell GP and Lyondell
LP, the failure to pay principal, when due, on the Lyondell Note, which failure
continues for at least five business days from the date such payment is due; or
(iii) the withdrawal, retirement, resignation or dissolution of a partner (other
than in connection with a transfer of all of a partner's units in accordance
with the Partnership Agreement); or the bankruptcy of a partner or its
guarantor.
 
     The day upon which the Default commences or occurs (or if the Default is
subject to a cure period and is not timely cured, then the day following the end
of the applicable cure period) shall be the 'Default Date.' Following a Default,
in addition to any other remedies they may have, the Non-Defaulting Partners in
their sole discretion may elect to pursue the following remedies: (i) at any
time prior to the expiration of 60 days from the Default Date, the
Non-Defaulting Partners may elect to purchase all, but not less than all, the
units of the Defaulting Partners as described below; provided, however, that
within 10 days after the determination of the fair market value, the
Non-Defaulting Partners may decide not to proceed with a purchase of the units
of the Defaulting Partners, in which case the Non-Defaulting Partners shall have
an additional 30 days following such decision to elect an alternative remedy
under clause (ii) below; and (ii) at any time prior to the expiration of 60 days
from the Default Date (or if the Non-Defaulting Partners initially elected to
pursue their remedy under clause (i) above, then at any time prior to the
expiration of the 30-day extension period), the Non-Defaulting Partners may
elect to effect a liquidation of the Partnership and thereby cause the
Partnership to dissolve. See ' -- Dissolution and Termination.'
 
     Upon any election to purchase a Defaulting Partners' units following a
Default, the purchase price that the Non-Defaulting Partners shall pay to the
Defaulting Partners for their units shall be an amount equal to (i) the amount
that the Defaulting Partners would receive in a liquidation (assuming that any
sale as described under 'Dissolution and Termination' below were for an amount
equal to the fair market value, without giving effect to any damages) reduced by
(ii) the unrecovered damages attributable to the Default by the Defaulting
Partners. If the Non-Defaulting Partners have a right to purchase the units of
the Defaulting Partners, they may first seek a determination of fair market
value by delivering notice in writing to the Defaulting Partners. The
Non-Defaulting Partners shall have 10 days from the final determination of fair
market value to elect to purchase the units of the Defaulting
 
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Partners, and the purchase shall be consummated within 60 days following the
date when the Non-Defaulting Partners give notice of such election, subject to
extension in certain circumstances. The Non-Defaulting Partners may assign, in
whole or in part, their right to purchase the units of the Defaulting Partners
to one or more third parties.
 
     If the Non-Defaulting Partners elect to dissolve the Partnership as a
result of a Default, any amount payable to the Defaulting Partners in the
resulting liquidation shall be reduced by, without duplication, any unrecovered
damages incurred by the Non-Defaulting Partner and the Non-Defaulting Partners'
Pro Rata share of any unrecovered damages incurred by the Partnership in
connection with the Default.
 
     Commencing on the Default Date and (i) prior to the Non-Defaulting
Partners' collection of Damages through the exercise of their legal remedies or
otherwise, or (ii) while the Non-Defaulting Partners are pursuing their remedies
as described above, the Representatives of the Defaulting General Partner shall
not have any voting or decisional rights with respect to matters requiring
Partnership Governance Committee Action, and such matters shall be determined
solely by the Representatives of the Non-Defaulting General Partner; provided,
however, that the foregoing loss of voting and decisional rights shall not occur
as a result of a Default caused solely by the bankruptcy of a partner or a
guarantor; and provided further, that except in the case of a Default resulting
from the failure to pay the principal of the Lyondell Note, the foregoing loss
of voting and decisional rights shall not apply to the unanimous voting
requirements in respect of changes in the scope of the Partnership's business,
the issuance, sale, redemption or acquisition of units or other equity
securities by the Partnership or any subsidiary, changes in respect of
accounting methods or tax elections or mergers, consolidations or conversions.
See ' -- Unanimous Voting Requirements.'
 
DISSOLUTION AND TERMINATION
 
     As long as there is at least one other General Partner (who is hereby
authorized in such event to conduct the business of the Partnership without
dissolution), the withdrawal, retirement, resignation, dissolution or bankruptcy
of a General Partner shall not dissolve the Partnership, but rather shall be a
Default as described above. See ' -- Default.' The Partnership shall be
dissolved, however, upon the happening of any one of the following events: (i)
the written determination of both General Partners to dissolve the Partnership,
(ii) the entry of a judicial decree of dissolution, (iii) any other act or event
which results in the dissolution of a limited partnership under the Delaware
Revised Uniform Limited Partnership Act (except as provided in the first
sentence of this paragraph); (iv) the election of the Non-Defaulting Partners to
effect a dissolution of the Partnership as described above (see ' -- Defaults');
or (v) after the delivery of a Deadlock Notice by a General Partner as described
above (see ' -- Strategic Plans and Annual Budgets; Expenses'), the written
determination by either General Partner to dissolve the Partnership.
 
     If the Partnership dissolves, it shall commence winding up pursuant to the
appropriate provisions of the Delaware Revised Uniform Limited Partnership Act
and the procedures set forth below. Notwithstanding the dissolution of the
Partnership, prior to the termination of the Partnership, the business of the
Partnership and the affairs of the partners, as such, shall continue to be
governed by the Partnership Agreement. The winding up of the Partnership shall
be conducted under the direction of the Partnership Governance Committee;
provided, however, that if the dissolution is caused by entry of a decree of
judicial dissolution, the winding up shall be carried out in accordance with
such decree. Generally, the Partnership shall attempt to sell all property and
apply the proceeds therefrom as described below. Upon dissolution of the
Partnership, the Partnership Governance Committee shall determine the time,
manner and terms of any sale or sales of the Partnership property pursuant to
such winding up, consistent with its duties and having due regard to the
activity and condition of the relevant market and general financial and economic
conditions. Except as otherwise agreed by the partners, no distributions will be
made in kind to any partner without the consent of each partner.
 
     In the case of a dissolution and winding-up of the Partnership, the
Partnership's assets shall be applied as follows: (i) to satisfaction of the
liabilities of the Partnership owing to third parties and then
 
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to partners (including affiliates of partners), whether by payment or reasonable
provision for payment; any reserves created to make any such provision for
payment may be paid over by the Partnership to an independent escrow holder or
trustee, to be held in escrow or trust for the purpose of paying any such
contingent, conditional or unmatured liabilities or obligations, and at the
expiration of such period as the Partnership Governance Committee may deem
advisable, such reserves shall be distributed to the partners or their assigns
in the manner set forth below; and then (ii) after all allocations of profits or
losses and other items to the partners in accordance with the balances in their
capital accounts; any partner that then has a deficit in its capital account
shall contribute cash in the amount necessary to eliminate such deficit and such
contributions shall be made within 90 days after the date in which all
undistributed assets of the Partnership have been converted to cash.
Notwithstanding the foregoing, if any partner shall be indebted to the
Partnership, then until payment in full of the principal of and accrued but
unpaid interest on such indebtedness, regardless of the stated maturity or
maturities thereof, the Partnership shall retain such partner's distributive
share of Partnership property and apply such sums to the liquidation of such
indebtedness and the cost of operation of such Partnership property during the
period of such liquidation.
 
     If dissolution occurs as a result of the delivery of a Deadlock Notice,
then, notwithstanding the foregoing and at the election of any partner,
properties shall be divided and distributed in kind to the partners in
accordance with certain provisions set forth in Appendix E to the Partnership
Agreement.
 
LIMITATION OF FIDUCIARY DUTIES; NON-COMPETITION
 
     The liability of each of the General Partners (including any liability of
its affiliates or its and their respective officers, directors, agents and
employees) or of any Limited Partner (including any liability of its affiliates
or its and their respective officers, agents, directors and employees), either
to the Partnership or to any other partner, for any act or omission by such
partner in its capacity as a partner of the Partnership that is imposed by such
partner's status as a 'general partner' or 'limited partner' (as such terms are
used in the Delaware Revised Uniform Limited Partnership Act) of a limited
partnership will be eliminated, waived and limited to the fullest extent
permitted by law; provided, however, that each General Partner shall at all
times owe to the other General Partner a fiduciary duty in observing the
requirement described above under ' -- Unanimous Voting Requirement' that two or
more Representatives of each of Lyondell GP and Millennium GP shall be required
to give their approval before the Partnership may undertake any of the actions
listed therein. Each General Partner shall at all times owe to the other General
Partner a duty to act in good faith with respect to all matters involving the
Partnership.
 
     Except as described below, each partner's affiliates shall be free to
engage in or possess an interest in any other business of any type, and to avail
itself of any business opportunity available to it without having to offer the
Partnership or any partner the opportunity to participate in such business. If a
partner's affiliate desires to initiate or pursue an opportunity to undertake,
engage in, acquire or invest in a business, activity or operation within the
scope of the business of the Partnership ('Related Business') by investing in or
acquiring a person whose business is a Related Business, acquiring assets of a
Related Business, or otherwise engaging in or undertaking a Related Business (a
'Business Opportunity'), such partner or its affiliate (such partner, together
with its affiliates being called the 'Proposing Partner') shall offer the
Partnership the Business Opportunity.
 
     When a Proposing Partner offers a Business Opportunity to the Partnership,
the Partnership shall elect to do one of the following: (i) acquire or undertake
the Business Opportunity for the benefit of the Partnership as a whole, at the
cost, expense and benefit of the Partnership; or (ii) permit the Proposing
Partner to acquire or undertake the Business Opportunity for its own benefit and
account without any duty to the Partnership or the other partners with respect
thereto; provided, however, that if the Business Opportunity is in direct
competition with the then existing business of the Partnership (a 'Competing
Opportunity'), then the Proposing Partner and the Partnership shall, if either
so elects, seek to negotiate and implement an arrangement whereby the
Partnership would either (i) acquire or undertake the Competing Opportunity at
the sole cost, expense and benefit of the Proposing Partner under a mutually
acceptable arrangement whereby the Competing Opportunity is treated as a
separate
 
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business within the Partnership with the costs, expenses and benefits related
thereto being borne and enjoyed solely by the Proposing Partner, or (ii) enter
into a management agreement with the Proposing Partner to manage the Competing
Opportunity on behalf of the Proposing Partner on terms and conditions mutually
acceptable to the Proposing Partner and the Partnership. If the Partnership and
the Proposing Partner do not reach agreement as to such arrangement, the
Proposing Partner may acquire or undertake the Competing Opportunity for its own
benefit and account without any duty to the Partnership or the other partners
with respect thereto.
 
     In addition, if the Business Opportunity constitutes less than 25% (based
on annual revenues for the most recently competed fiscal year) of an acquisition
of or investment in assets, activities, operations or businesses that is not
otherwise a Related Business, then a Proposing Partner may acquire or invest in
such Business Opportunity without first offering it to the Partnership;
provided, that, after completion of the acquisition or investment thereof, such
Proposing Partner must offer the Business Opportunity to the Partnership as
described above. If the Partnership elects to pursue such Business Opportunity,
it shall be acquired by the Partnership at its fair market value as of the date
of such acquisition.
 
     If (i) the Partnership is presented with an opportunity to acquire or
undertake a Business Opportunity that it determines not to acquire or undertake
and (ii) the Representatives of one General Partner, but not the other General
Partner, desired that Partnership acquire or undertake such Business
Opportunity, then the Partnership shall permit such first General Partner and
its affiliates to acquire or undertake such Business Opportunity, and such
Business Opportunity shall be treated in the same manner as if such General
Partner and its affiliates were a Proposing Partner with respect to such
Business Opportunity.
 
FINANCIAL AND ACCOUNTING MATTERS; AUDITS
 
     The fiscal year of the Partnership will begin on January 1 and end on
December 31. The initial independent auditors of the Partnership will be
appointed by mutual agreement of Lyondell and Millennium, and this appointment
may only be changed with the approval of at least two Representatives of each of
Lyondell GP and Millennium GP. See ' -- Unanimous Voting Requirements.' The
Partnership will report its operations for tax purposes utilizing the accrual
method of accounting. The Partnership will give each partner, as well as its
internal and independent auditors, at the expense of such partner, full and
complete access to the Partnership's internal and independent auditors. Each
partner shall have the right to inspect the books and records and the physical
properties of the Partnership and, at its own expense, to cause an independent
audit thereof at any time.
 
FINANCIAL AND OTHER INFORMATION
 
     The Partnership shall deliver to each partner certain monthly, quarterly
and annual reports and financial statements as specified in the Partnership
Agreement.
 
                                       76
<PAGE>
<PAGE>
                              THE PARENT AGREEMENT
 
     The following is a summary of the material provisions of the Parent
Agreement, which has been filed with the SEC and is incorporated herein by
reference. This summary is qualified in its entirety by reference to the full
and complete text of the Parent Agreement. All holders of Lyondell Common Stock
and Millennium Common Stock are encouraged to read the Parent Agreement
carefully. See 'Where You Can Find More Information.'
 
GUARANTEE OF OBLIGATIONS
 
     Each of Lyondell and Millennium (the 'Parents') shall guarantee, undertake
and promise to cause the due and punctual payment and the full and prompt
performance by its respective subsidiaries, Lyondell GP and Lyondell LP in the
case of Lyondell (the 'Lyondell Partner Subs') and Millennium GP and Millennium
LP in the case of Millennium (the 'Millennium Partner Subs' and, together with
the Lyondell Partner Subs, the 'Affiliated Obligors') of all of the amounts to
be paid and all of the terms and provisions to be performed or observed by or on
the part of its Affiliated Obligors under the various agreements, including,
without limitation, the Partnership Agreement and the Asset Contribution
Agreements (the 'Other Agreements'), in accordance with the terms thereof (all
such terms and provisions collectively called the 'Obligations') as follows: in
the event that its Affiliated Obligors shall fail in any manner whatsoever to
timely pay, perform or observe any of their Obligations, such Parent will itself
duly and punctually pay, or fully and promptly perform or observe, as the case
may be, such Obligations, or cause the same to be duly and punctually paid, or
fully and promptly performed or observed, in each case as if such Parent were
itself the obligor with respect to such Obligations under the Other Agreements.
 
     Further, each of Lyondell and Millennium shall acknowledge that the
Partnership Agreement sets forth definitions of 'Conflicted Partner' and
'Nonconflicted Partner,' and provides that a Nonconflicted Partner has certain
exclusive rights to control the Partnership with respect to any Conflict
Circumstance (as defined in the Partnership Agreement). Without limiting the
rights of its Partner Sub under the Partnership Agreement, each of Lyondell and
Millennium shall agree to cause its Partner Sub (i) to cause the Partnership to
pay, perform and observe all of the Obligations to be paid, performed or
observed by or on the part of the Partnership under the Other Agreements, in
accordance with the terms thereof, to the extent that such Partner Sub is the
Nonconflicted Partner and is thereby entitled to cause the payment, performance
and observance of such Obligations and (ii) to abide by its obligations as the
Nonconflicted Partner with respect to any Conflict Circumstance in accordance
with the terms of the Partnership Agreement applicable thereto; provided,
however, that each of Lyondell's or Millennium's responsibility for a failure of
the Partnership to pay, perform or observe its obligations under the Other
Agreements shall be limited to the circumstances in which the Partnership's
failure to so pay, perform or observe its obligations under the Other Agreements
was directly caused by an act or failure to act by its Partner Sub; provided,
further, that nothing in this paragraph shall require Lyondell or Millennium to
make or cause such Partner Sub to make any contribution to the Partnership that
such Partner Sub is not otherwise required to make pursuant to the Partnership
Agreement. See 'The Partnership Agreement -- Transactions with Affiliates.'
 
RESTRICTIONS ON TRANSFER AND PLEDGE OF PARTNER SUB STOCK
 
     Lyondell and Millennium also shall agree that except as otherwise provided
below or with the written consent of the other, which consent may be granted or
withheld in such other party's sole discretion, it will not, in any transaction
or series of transactions, directly or indirectly, (i) sell, assign or otherwise
in any manner dispose of, whether by act, deed, merger or otherwise ('Transfer')
or (ii) mortgage, pledge, encumber or create or suffer to exist any pledge, lien
or encumbrance upon or security interest in ('Pledge'), all or any part of the
capital stock (including any securities convertible into or exchangeable for or
carrying any rights to purchase, subscribe for or otherwise acquire any such
capital stock) of its Partner Subs (collectively, the 'Partner Sub Stock'). Any
attempt by Lyondell or Millennium to Transfer or Pledge all or a portion of its
Partner Sub Stock in violation of the Parent Agreement shall be void ab initio
and shall not be effective to transfer such Partner Sub Stock or any portion
thereof.
 
                                       77
 <PAGE>
<PAGE>
     Lyondell or Millennium may Transfer all (but not less than all) of its
Partner Sub Stock if such Transfer is in connection with (i) a merger,
consolidation, conversion or share exchange of such entity or (ii) a sale or
other disposition of (x) the Partner Sub Stock plus (y) other assets
representing at least fifty percent (50%) of the book value of such entity's
assets excluding the Partner Sub Stock, as reflected on its most recent audited
consolidated (or combined) financial statements; provided, however, the ultimate
parent entity of the acquiring, succeeding or surviving entity in any such
transaction (the 'Successor Parent') (i) shall succeed to and be substituted for
Lyondell or Millennium as applicable, with the same effect as if it had been
named in the Parent Agreement and (ii) shall execute an instrument wherein such
ultimate parent entity shall agree to be bound by the obligations of Lyondell or
Millennium, as applicable, under the Parent Agreement, with the same effect as
if it had been named therein, whereupon, unless Lyondell or Millennium, as
applicable, shall become a direct or indirect subsidiary of the Successor
Parent, Lyondell or Millennium, as applicable, shall thereupon be released from
all obligations under the Parent Agreement.
 
     Lyondell or Millennium may Pledge all (but not less than all) of its
Partner Sub Stock to any one or more Approved Lenders; provided that the Pledge
shall be evidenced by an instrument reasonably satisfactory to the Partnership,
wherein the Approved Lender receiving such Pledge shall agree that in the event
such Approved Lender obtains a right of foreclosure on such Parent's Partner Sub
Stock, such Approved Lender will foreclose on the Partner Sub Stock of each of
Lyondell's or Millennium's, as the case may be, Partner Subs equally so that
such Approved Lender will in all events hold equal portions of Partner Sub Stock
of Lyondell GP and Lyondell LP or Millennium GP and Millennium LP, as the case
may be. An 'Approved Lender' shall be any bank, insurance company, investment
bank or other financial institution that is regularly engaged in the business of
making loans.
 
RIGHT OF FIRST OPTION
 
     Without the consent of the other, neither Lyondell or Millennium may
Transfer less than all of its Partner Sub Stock. Unless such Transfer is
otherwise permitted by the foregoing paragraphs concerning restrictions, either
party desiring to Transfer (pursuant to a cash sale) all of its Partner Sub
Stock (the 'Selling Parent') shall give written notice (the 'Initial Notice') to
the Partnership and the other party (the 'Offeree Parent') stating that the
Selling Parent desires to Transfer its Partner Sub Stock and stating the cash
purchase price and all other terms on which it is willing to sell (the 'Offer
Terms'). Delivery of an Initial Notice shall constitute the irrevocable offer of
the Selling Parent to sell its Partner Sub Stock to the Offeree Parent. The
Offeree Parent shall have the option, exercisable by delivering written notice
of such exercise to the Selling Parent within 45 days of the date of the Initial
Notice, to elect to purchase all of the Partner Sub Stock of the Selling Parent
on the Offer Terms described in the Initial Notice. If the Offeree Parent does
not elect to purchase the Selling Parent's Partner Sub Stock within 45 days
after the receipt of the Initial Notice, the Selling Parent shall have a further
180 days during which it may consummate the sale of its Partner Sub Stock to a
third party purchaser at a purchase price and on such other terms that are no
more favorable to such purchaser than the Offer Terms and in accordance with and
subject to such other provisions of the Parent Agreement as may apply. If the
sale is not completed within such further 180-day period, the Initial Notice
shall be deemed to have expired and a new notice and offer shall be required
before the Selling Parent may make any Transfer of its Partner Sub Stock.
 
STANDSTILL AGREEMENT
 
     Lyondell and Millennium shall agree that, until the expiration of 24 months
from the date on which either it and its affiliates or the other party and its
affiliates no longer hold an interest in the Partnership, neither it, nor any of
its Affiliated Obligors or other subsidiaries, shall, without prior written
approval of the other party: (i) in any manner acquire, agree to acquire or make
any proposal to acquire, directly or indirectly, any securities, assets or
property of the other party (other than such party's Partner Sub Stock or the
interests in the Partnership held by such Parent's Partner Subs), whether such
agreement or proposal is made with or to the other party or a third party; (ii)
make any unsolicited proposal to enter into, directly or indirectly, any merger
or other business combination involving the other party; (iii) make, or in any
way participate, directly or indirectly, in any
 
                                       78
 <PAGE>
<PAGE>
'solicitation' of 'proxies' (as such terms are used in the proxy rules of the
SEC) to vote, or seek to advise or influence any person with respect to the
voting of, any voting securities of the other party; (iv) form, join or in any
way participate in a 'group' (within the meaning of Section 13(d)(3) of the
Exchange Act) with respect to any voting securities of the other party; (v)
otherwise act, alone or in concert with others, to seek to control or influence
the management, Board of Directors or policies of the other party (other than
with respect to the ownership, business, property and affairs of the
Partnership); (vi) disclose any intention, plan or arrangement inconsistent with
the foregoing; or (vii) advise, encourage, provide assistance (including
financial assistance) to or hold discussions with any other persons in
connection with any of the foregoing. Lyondell and Millennium will also agree
during such period not to: (i) request the other party (or its directors,
officers, employees or agents), directly or indirectly, to amend or waive any
provision of this paragraph; or (ii) take any action which might reasonably be
expected to require the other party to make a public announcement regarding the
possibility of a business combination or merger.
 
     Notwithstanding the foregoing paragraph, either Lyondell or Millennium may,
by notice to the other, terminate the provisions of the foregoing paragraph (as
applied to both parties) at any time within 30 days after the occurrence of any
of the following events with respect to the other party: (i) certain changes of
control of such other party shall have occurred, (ii) such other party shall
have entered into a definitive agreement providing for, or publicly announced
its intention to effect, any transaction involving certain changes of control of
such other party or (iii) a tender offer or exchange offer shall have been
commenced or publicly announced by a third party that, if consummated, would
have the effect of acquiring beneficial ownership of 50% or more of the voting
stock of such other party.
 
COMPETING BUSINESS
 
     If either Lyondell or Millennium desires to initiate or pursue any
opportunity to undertake, engage in, acquire or invest in a Business Opportunity
(as such term is defined in the Partnership Agreement), it shall agree to offer
such Business Opportunity to the Partnership under the terms and conditions set
forth in the Partnership Agreement as if it were the 'Proposing Partner' (as
defined in the Partnership Agreement) with respect thereto, and in such event
the Partnership shall have the rights and obligations with respect thereto set
forth in the Partnership Agreement. See 'The Partnership Agreement -- Limitation
of Fiduciary Duties; Non-Competition.'
 
                       CERTAIN RELATED PARTY TRANSACTIONS
 
     Following the Closing, the Partnership will enter into a series of
operating and services agreements with Lyondell affiliates and with Millennium,
including, among other matters, the following:
 
          (i) The Partnership will provide operating and other services for
     Lyondell Methanol under the terms of existing agreements that will be
     assigned to the Partnership. Pursuant to the terms of those agreements,
     Lyondell Methanol will pay the Partnership a management fee of $6 million
     per year and will reimburse certain Partnership expenses at cost.
 
          (ii) Lyondell's rights and obligations under the terms of its product
     sales and feedstock purchase agreements with its refinery affiliate,
     LYONDELL-CITGO Refining, will be assigned to the Partnership. Accordingly,
     certain refinery products (propane, butane, low-octane, naphthas, heating
     oils and gas oils) will be sold to the Partnership as feedstocks and
     certain olefins by-products will be sold to LYONDELL-CITGO Refining for
     processing into gasoline. The Partnership will also assume certain tolling
     arrangements, as well as terminalling and storage obligations between
     Lyondell and LYONDELL-CITGO Refining and will perform certain marketing
     services for LYONDELL-CITGO Refining. All of the agreements between
     LYONDELL-CITGO Refining and the Partnership will be on terms generally
     representative of prevailing market prices.
 
          (iii) The Partnership and Millennium have negotiated a variety of
     operating, manufacturing and technical service agreements related to the
     business of the Partnership and the VAM, acetic acid, synthesis gas and
     methanol businesses that will be retained by Millennium Petrochemicals.
 
                                       79
 <PAGE>
<PAGE>
     These agreements will be entered into on terms that are generally
     representative of prevailing market prices.
 
          (iv) Lyondell, Millennium and the Partnership will enter into an
     administrative services agreements pursuant to which each of Lyondell and
     Millennium will provide certain administrative services to the Partnership
     and the Partnership may provide certain administrative services to Lyondell
     and Millennium. These services will be reimbursed at cost.
 
          (v) Lyondell will assign office space and other leasehold interests to
     the Partnership and sublease from the Partnership office space for its
     headquarters.
 
          (vi) Millennium will assign certain leasehold interests to the
     Partnership and sublease from the Partnership certain administrative office
     space.
 
                            MARKET PRICE INFORMATION
 
     The Lyondell Common Stock is listed and traded on the New York Stock
Exchange ('NYSE') under the symbol 'LYO.' On July 25, 1997, the day preceding
the first public announcement of the Joint Venture Transaction, the high and low
sale prices of Lyondell Common Stock were $25 3/4 and $23 15/16, respectively.
 
     The Millennium Common Stock is listed and traded on the 'NYSE' under the
symbol 'MCH.' On July 25, 1997, the day preceding the first public announcement
of the Joint Venture Transaction, the high and low sale prices of Millennium
Common Stock were $20 15/16 and $20 9/16, respectively.
 
                         MANAGEMENT OF THE PARTNERSHIP
 
EXECUTIVE OFFICERS
 
     The table below sets forth the names and ages of the persons expected to be
executive officers of the Partnership upon consummation of the Joint Venture
Transaction.
 
<TABLE>
<CAPTION>
                NAME                   AGE                  POSITION WITH THE PARTNERSHIP
- ------------------------------------   ---   -----------------------------------------------------------
 
<S>                                    <C>   <C>
Dan F. Smith........................   51    Chief Executive Officer
Eugene R. Allspach..................   50    President and Chief Operating Officer
Joseph M. Putz......................   56    Senior Vice President, Finance and Administration
Debra L. Starnes....................   44    Senior Vice President, Polymers
John R. Beard.......................   45    Vice President, Manufacturing
J. R. Fontenot......................   45    Vice President, Engineering
Alan Houlton........................   51    Vice President, Customer Supply Chain
Gerald A. O'Brien...................   45    Vice President and Secretary
Myra J. Perkinson...................   46    Vice President, Human Resources
W. Norman Phillips, Jr..............   42    Vice President, Petrochemicals
Kerry F. Williams...................   54    Vice President, Research and Development
Jeffrey L. Hemmer...................   39    Director, Business Process Improvement
</TABLE>
 
     There are no family relationships among any of the executive officers of
the Partnership, on the one hand, and any directors or executive officers of
either Lyondell or Millennium, on the other hand.
 
EXPERIENCE OF EXECUTIVE OFFICERS
 
     MR. SMITH has been Chief Executive Officer of Lyondell since December 1996.
He will remain in this capacity while serving as Chief Executive Officer of the
Partnership (and will not be an employee of the Partnership). Mr. Smith has been
a Director of Lyondell since 1988 and President since 1994. Mr. Smith also
served as Chief Operating Officer of Lyondell from 1994 to December 1996. Prior
to 1994, Mr. Smith held various positions including Executive Vice President and
Chief Financial Officer of Lyondell, Vice President, Corporate Planning of ARCO
and Senior Vice President in the areas of management, manufacturing, control and
administration for Lyondell and the Lyondell Division of ARCO.
 
                                       80
 <PAGE>
<PAGE>
     MR. ALLSPACH has been Group Vice President, Manufacturing and Technology
for Millennium Petrochemicals since 1993. In such position, Mr. Allspach has
been responsible for manufacturing, research and development, purchasing,
engineering and Millennium Petrochemicals' ethylene business group. Between 1991
and 1993, he was Group Vice President, Manufacturing and Manufacturing Services
for Quantum.
 
     MR. PUTZ has served as Vice President and Controller of Lyondell since
October, 1988. Prior to 1988, Mr. Putz served as Vice President, Control and
Administration for Lyondell and the Lyondell Division of ARCO and held various
positions with ARCO in internal control, special projects and various financial
positions.
 
     MS. STARNES became Senior Vice President, Petrochemicals of Lyondell in
January 1997. Ms. Starnes has served Lyondell as a Senior Vice President since
1995 and as a Vice President since 1991 with various responsibilities including
polymers, petrochemicals business management and marketing and corporate
planning. Prior to 1991, Ms. Starnes held various positions in planning,
manufacturing and marketing with ARCO and Lyondell.
 
     MR. BEARD has served as Vice President, Petrochemical Manufacturing of
Lyondell since May 1995. Mr. Beard served as Vice President in the areas of
Quality, Supply, Planning and Evaluations of Lyondell since 1992. Prior to 1992,
Mr. Beard served as the Site Manager of Lyondell's Houston Refinery and in
management assignments in evaluations, marketing and manufacturing for Lyondell,
ARCO Products Company and the ARCO Chemical Division.
 
     MR. FONTENOT became Vice President, Technology of Lyondell in January 1997.
Mr. Fontenot served as Director of Technology for Lyondell since 1995. Prior to
1995, Mr. Fontenot held various positions in operations, evaluations and
technology for Lyondell.
 
     MR. HOULTON has served as Vice President, Manufacturing for Millennium
Petrochemicals, with responsibility for Millennium Petrochemicals' eleven
manufacturing and compounding operations, since October 1993. Prior to such
time, he was plant manager of Millennium Petrochemicals' Clinton, Iowa
petrochemical facility.
 
     MR. O'BRIEN has been associate general counsel of Lyondell since 1989. His
responsibilities include joint responsibility for the management of the Legal
Department and responsibility for a variety of legal department functions,
including mergers and acquisitions, general corporate, finance and securities.
 
     MS. PERKINSON has served as Vice President, Human Resources/Communications
for Millennium Petrochemicals since November 1991, in which position she was
responsible for all human resources, employee relations and labor relations
functions and for the administration of all Millennium Petrochemicals'
compensation, benefits and communications programs. Prior to such time, she was
Director, Customer Service and Transportation for Millennium Petrochemicals.
 
     MR. PHILLIPS was named Vice President, Polymers of Lyondell in January
1997. Mr. Phillips has served as Vice President of Lyondell with
responsibilities in the areas of marketing and operations since 1993. Prior to
1993, Mr. Phillips held the position of Site Manager of Lyondell's Channelview
Operations and various management positions in the areas of planning, marketing
and manufacturing.
 
     MR. WILLIAMS has served as Vice President, Research and Development for
Millennium Petrochemicals since November 1996, and is responsible for Millennium
Petrochemicals' polyethylene, chemical, specialty and fundamental research and
development activities. Prior to such time, he was the head of the research and
development and technology transfer functions at Amoco Corporation's Chemical
Intermediate Business Groups.
 
     MR. HEMMER has been Director, Engineering and Licensing for Millennium
Petrochemicals since October 1996, and is responsible for project processes,
specialized engineering functions, manufacturing technology, capital expansions
and cost reduction programs, as well as for the out-licensing of Millennium
Petrochemicals' catalyst, process and product technologies. Prior to such time,
he was manager of polyethylene process and engineering technology for Exxon
Chemical.
 
                                       81
 <PAGE>
<PAGE>
EXECUTIVE AGREEMENTS
 
     It is anticipated that the Partnership will create new incentive plans for
its executive officers and employees. The incentive plans for the Partnership's
executive officers are anticipated to include awards based on the timely
achievement of the Synergies, as well as the creation of economic value added.
 
     Each of the executive officers of Lyondell who will become an employee and
executive officer of the Partnership has a severance agreement that will be
assigned to the Partnership. These severance agreements are described under 'The
Proposed Joint Venture -- Interests of Certain Persons in the Joint Venture
Transaction.'
 
                       OWNERSHIP OF LYONDELL COMMON STOCK
                  BY CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
 
CERTAIN BENEFICIAL OWNERS
 
     Prior to September 15, 1997, Lyondell's principal stockholder was ARCO, one
of the nation's leading integrated oil companies, which maintains its
headquarters at 515 South Flower Street, Los Angeles, California 90039. ARCO,
following the initial public offering of Lyondell Common Stock in January 1989,
owned 39,921,400 shares of Lyondell Common Stock, which represented 49.9% of the
outstanding shares of Lyondell Common Stock. In August 1994, ARCO completed an
offering of three-year debt securities (the 'ARCO Notes'). Upon maturity at
September 15, 1997, the principal amount of the ARCO Notes became due and
payable in shares of Lyondell Common Stock. Effective September 15, 1997, ARCO
exchanged the ARCO Notes into        shares of Lyondell Common Stock. ARCO now
holds less than 5% of the outstanding Lyondell Common Stock.
 
     The table below sets forth certain information as of the most recent date
as of which Lyondell has information regarding the beneficial ownership of
Lyondell Common Stock by persons known by Lyondell to beneficially own more than
5% of its outstanding shares of Lyondell Common Stock.
 
<TABLE>
<CAPTION>
                                                                          NUMBER OF SHARES       % OF
                           NAME AND ADDRESS                                 BENEFICIALLY        SHARES
                          OF BENEFICIAL OWNER                                  OWNED          OUTSTANDING
- -----------------------------------------------------------------------   ----------------    -----------
 
<S>                                                                       <C>                 <C>
Wellington Management Company, LLP(a) .................................       7,524,900           9.3%
  75 State Street
  Boston, Massachusetts 02109
Brinson Partners, Inc. (b) ............................................       6,145,826           7.7%
  209 South LaSalle
  Chicago, Illinois 60604-1295
FMR Corporation (c) ...................................................       4,666,096           5.6%
  82 Devonshire Street
  Boston, Massachusetts 02109
State Street Bank and Trust Company(d) ................................       4,199,096           5.3%
  225 Franklin Street
  Boston, Massachusetts 02110
</TABLE>
 
- ------------
 
 (a) Wellington Management Company, LLP ('WMC') (together with its wholly-owned
     subsidiary, Wellington Trust Management Company, N.A.) may be deemed a
     beneficial owner of the 7,524,900 shares by virtue of the direct or
     indirect investment and/or voting discretion they possess pursuant to the
     provisions of investment advisory agreements with clients, including the
     Vanguard/Windsor Fund, Inc. ('Vanguard'). WMC has shared dispositive power
     over the 7,524,900 shares and shared voting power over 114,300 shares.
 
 (b) Brinson Partners, Inc. ('BPI') (together with its wholly-owned subsidiary,
     Brinson Trust Company ('BTC'), and its parent holding companies, Brinson
     Holdings, Inc. ('BHI'), SBC Holding (USA), Inc. ('SBCUSA') and Swiss Bank
     Corporation ('SBC') may be deemed a beneficial owner of the 6,145,826
     shares by virtue of the direct or indirect investment and/or voting
     discretion they possess pursuant to the provisions of investment advisory
     agreements with clients. BPI, SBCISA, SBC and BHI have shared voting and
     shared dispositive power over all 6,145,826 shares. BTC has shared voting
     and dispositive power with respect to 1,157,500 shares.
 
                                              (footnotes continued on next page)
 
                                       82
 <PAGE>
<PAGE>
(footnotes continued from previous page)
 
 (c) FMR Corporation ('FMR') (together with its affiliated entities) may be
     deemed a beneficial owner of the 4,666,096 shares by virtue of the direct
     or indirect investment and/or voting discretion they possess pursuant to
     the provisions of investment advisory agreements with clients. The number
     of shares owned by FMR and its affiliates as of December 31, 1996 included
     3,064,732 shares resulting from the assumed conversion of the ARCO Notes
     held by such affiliates as of such date (assuming a prescribed exchange
     rate of 0.892857 shares of Common Stock per ARCO Note). FMR has the sole
     dispositive power over 4,426,932 shares owned or deemed to be owned by the
     Funds to which its wholly-owned subsidiary, Fidelity Management & Research
     Company ('Fidelity') acts as an advisor. The power to vote or direct the
     voting of such shares resides with the Funds' Boards of Directors and
     Fidelity carries out the voting of the shares under written guidelines
     established by the Funds' Boards of Directors. FMR has the sole dispositive
     power over 239,164 shares owned or deemed to be owned by Fidelity
     Management & Trust Company ('FMTC'), its wholly-owned subsidiary serving as
     investment manager of institutional accounts. FMR has sole voting power
     with respect to 163,271 of those shares and no voting power with respect to
     75,893 of those shares. The 239,164 shares FMTC owned included 121,964
     shares resulting from the assumed conversion of the ARCO Notes held by FMTC
     as of such date (assuming a prescribed exchange rate of 0.892857 shares of
     Common Stock per ARCO Note).
 
 (d) State Street Bank and Trust Company ('State Street'), Trustee for (i) the
     Lyondell Petrochemical Company 401(k) and Savings Plan; (ii) the
     LYONDELL-CITGO Refining Company Ltd. 401(k) and Savings Plans; (iii)
     various collective investment funds for employee benefit plans and other
     index accounts; and (iv) various trust accounts as Co-Trustee with the
     Barnes Group may be deemed a beneficial owner of the 4,199,096 shares by
     virtue of the direct or indirect investment and/or voting discretion it
     possesses pursuant to the provisions of investment advisory agreements with
     clients. State Street has sole voting power over 543,700 shares and shared
     voting power over 3,244,396 shares, sole dispositive power over 952,400
     shares and shared dispositive power over 3,246,696 shares.
 
DIRECTORS AND EXECUTIVE OFFICERS
 
     The following table sets forth the number of shares of Common Stock owned
beneficially as of July 1, 1997 by each director, each of the current executive
officers named in the Summary Compensation Table included in the Proxy Statement
with respect to Lyondell's 1997 Annual Meeting and by all current directors and
executive officers as a group. Unless otherwise noted, each individual has sole
voting and investment power.
 
<TABLE>
<CAPTION>
                                                                          NUMBER OF SHARES        % OF
                                                                         BENEFICIALLY OWNED      SHARES
                                 NAME                                          (a)(b)          OUTSTANDING
- ----------------------------------------------------------------------   ------------------    -----------
 
<S>                                                                      <C>                   <C>
William J. Butler.....................................................           4,624               *
Curtis J. Crawford....................................................           1,873               *
Travis Engen..........................................................           2,873               *
Stephen F. Hinchliffe, Jr.............................................           5,733               *
Dudley C. Mecum II....................................................           2,573               *
Richard W. Park.......................................................          52,177               *
Jeffrey R. Pendergraft................................................          38,832(d)            *
Dan F. Smith..........................................................          80,981               *
Paul R. Staley........................................................           2,123               *
Debra L. Starnes......................................................          65,939(e)            *
Russell S. Young......................................................          69,249(f)            *
All directors and executive officers as a group (16)..................         480,312(g)            *
</TABLE>
 
- ------------
 
  * Represents less than 1%
 
 (a) Includes shares held by the trustee under the Lyondell 401(k) and Savings
     Plan for the accounts of participants as of December 31, 1996.
 
                                              (footnotes continued on next page)
 
                                       83
 <PAGE>
<PAGE>
(footnotes continued from previous page)
 
 (b) The amounts shown include shares that may be acquired within 60 days
     following September 1, 1997 through the exercise of stock options, as
     follows: Mr. Smith, 25,950; Mr. Pendergraft, 47,225; Mr. Young, 36,025; Ms.
     Starnes, 30,350; Mr. Park, 29,775 and all directors and executive officers
     as a group, including those just named, 239,069.
 
 (c) Does not include 1,000 shares held by a trust of which Mr. Hinchliffe is a
     trustee, as to which shares he disclaims beneficial ownership.
 
 (d) Includes 3,239 shares as to which Mr. Pendergraft shares beneficial
     ownership.
 
 (e) Does not include approximately 8,000 shares owned by Ms. Starnes' spouse,
     as to which shares she disclaims beneficial ownership.
 
 (f) Does not include 1,100 shares owned by Mr. Young's spouse, as to which
     shares he disclaims beneficial ownership.
 
 (g) Does not include the approximate 10,100 shares owned by spouses and a
     trust, as to which shares beneficial ownership is disclaimed.
 
                      OWNERSHIP OF MILLENNIUM COMMON STOCK
                  BY CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
 
CERTAIN BENEFICIAL OWNERS
 
     The following is the only person known by Millennium as of                ,
1997 to own beneficially more than 5% of the outstanding Millennium Common Stock
as of the Record Date, based on available SEC filings.
 
<TABLE>
<CAPTION>
                                                                          NUMBER OF SHARES       % OF
                           NAME AND ADDRESS                                 BENEFICIALLY        SHARES
                          OF BENEFICIAL OWNER                                  OWNED          OUTSTANDING
- -----------------------------------------------------------------------   ----------------    -----------
 
<S>                                                                       <C>                 <C>
Barrow, Hanley, Mewhinney & Strauss, Inc. .............................       8,389,952(1)        10.9
  One McKinney Plaza
  3232 McKinney Avenue, 15th Floor
  Dallas, Texas 75204-2429
</TABLE>
 
(1) Based on a Schedule 13G filed with the SEC on August 18, 1997, Barrow,
    Hanley, Mewhinney & Strauss, Inc. has sole dispositive power over 8,389,952
    shares, sole voting power over 1,417,970 shares and shared voting power over
    6,971,982 shares.
 
DIRECTORS AND EXECUTIVE OFFICERS
 
     The following table, which is based upon information provided to
Millennium, sets forth the beneficial ownership of Millennium Common Stock, as
of July 31, 1997, by each of the directors, each of the executive officers named
in the Summary Compensation Table included in the Proxy Statement with respect
to Millennium's 1997 Annual Meeting and all Millennium directors and executive
officers as a group:
 
                                       84
 <PAGE>
<PAGE>
 
<TABLE>
<CAPTION>
                                                                          NUMBER OF SHARES       % OF
                                                                            BENEFICIALLY        SHARES
                                 NAME                                          OWNED          OUTSTANDING
- -----------------------------------------------------------------------   ----------------    -----------
 
<S>                                                                       <C>                 <C>
William M. Landuyt.....................................................         474,080(a)          *
Robert E. Lee..........................................................         334,584(b)          *
The Rt. Hon. Kenneth Baker CH MP.......................................             742(c)          *
Worley H. Clark........................................................             813(c)          *
Martin D. Ginsburg.....................................................             671(c)          *
The Rt. Hon. The Lord Glenarthur.......................................             971(c)          *
David J. P. Meachin....................................................             671(c)          *
Martin G. Taylor.......................................................           9,242(c)          *
George H. Hempstead, III...............................................         239,215(d)          *
John E. Lushefski......................................................         239,372(e)          *
George W. Robbins......................................................         227,934(f)          *
All directors and executive officers as a group (17 persons, including
  the foregoing).......................................................       2,023,809           2.6
</TABLE>
 
- ------------
 
  * Represents less than 1%
 
 (a) Includes 448,053 shares of restricted Common Stock awarded under
     Millennium's Long-Term Stock Incentive Plan of which 336,040 are subject to
     vesting pursuant to performance criteria and the remainder are subject to
     time vesting; 6,512 shares of Common Stock held in Millennium's 401(k) plan
     for Mr. Landuyt's account as of June 30, 1997; 885 shares of Common Stock
     held in Mr. Landuyt's spouse's name; and, 1,054 shares of Common Stock held
     in each of two trusts for Mr. Landuyt's children.
 
 (b) Includes 313,637 shares of restricted Common Stock awarded under
     Millennium's Long-Term Stock Incentive Plan, of which 235,228 are subject
     to vesting pursuant to performance criteria and the remainder are subject
     to time vesting; 6,513 shares of common Stock held in Millennium's 401(k)
     plan for Mr. Lee's account as of June 30, 1997; 3,261 shares held in
     Millennium's Salary and Bonus Deferral Plan as of July 31, 1997; and nine
     shares owned directly by members of Mr. Lee's immediate family, as to which
     Mr. Lee disclaims beneficial ownership.
 
 (c) Includes 671 shares issued under Millennium's Long-Term Stock Incentive
     Plan in partial payment of annual Directors' fees.
 
 (d) Includes 224,026 shares of restricted Millennium Common Stock awarded under
     Millennium's Long-Term Stock Incentive Plan, of which 168,020 are subject
     to vesting pursuant to performance criteria and the remainder are subject
     to time vesting; and 9,216 shares of Millennium Common Stock held in
     Millennium's 401(k) plan for Mr. Hempstead's account as of January 31,
     1997.
 
 (e) Includes 224,026 shares of restricted Millennium Common Stock awarded under
     Millennium's Long-Term Stock Incentive Plan, of which 168,020 are subject
     to vesting pursuant to performance criteria and the remainder are subject
     to time vesting; 11,907 shares of Common Stock held in Millennium's 401(k)
     plan for Mr. Lushefski's account as of January 31, 1997; and 12 shares
     owned by Mr. Lushefski's wife, as to which Mr. Lushefski disclaims
     beneficial ownership.
 
 (f) Includes 224,026 shares of restricted Millennium Common Stock awarded under
     Millennium's Long-Term Stock Inventive Plan, of which 168,020 are subject
     to vesting pursuant to performance criteria and the remainder are subject
     to time vesting; 2,670 shares of Millennium Common Stock held in
     Millennium's 401(k) plan for Mr. Robbins' account as of January 31, 1997;
     and, 71 shares of Millennium Common Stock held in a trust of which Mr.
     Robbins is a trustee, as to which Mr. Robbins disclaims beneficial
     ownership.
 
                          FUTURE STOCKHOLDER PROPOSALS
 
     Any Lyondell stockholder who intends to submit a proposal for inclusion in
the proxy materials for the 1998 annual meeting of Lyondell must submit such
proposal to the Secretary of Lyondell by November 28, 1997. In addition, the
Lyondell Bylaws provide that any Lyondell stockholder wishing to make a
nomination for director at the 1998 annual meeting of Lyondell must give written
notice to the
 
                                       85
 <PAGE>
<PAGE>
Secretary of Lyondell of his or her intention to make such a nomination. The
notice of nomination must be received by Lyondell not less than 90 days in
advance of such meeting, or if the meeting was not publicly announced by a
mailing to the stockholders, in a press release reported by the Dow Jones News
Service, the Associated Press or a comparable national news service or a filing
with the SEC more than 90 days prior to the meeting, must be delivered to the
Board of Directors not later than the close of business on the tenth day
following the day on which the date of the meeting was first so publicly
announced. The notice of nomination is required to contain certain information
about both the nominee and the stockholder making the nomination. A nomination
that does not comply with the above procedure will be disregarded. A copy of the
Lyondell Bylaws may be obtained from the Secretary of Lyondell at the address
set forth under 'Where You Can Find More Information.'
 
     Any Millennium stockholder who intends to submit a proposal for inclusion
in the proxy materials for the 1998 annual meeting of Millennium must submit
such proposal to the Secretary of Millennium by December 1, 1997. In addition,
the Millennium Bylaws provide that any stockholder wishing to make a nomination
for director, or wishing to introduce a proposal or other business, at the 1998
annual meeting of Millennium must notify the Secretary of Millennium of the
stockholder's intentions and provide certain other information in advance of
such meeting in accordance with the procedures detailed in the Millennium Bylaws
60 days or more before such meeting. A copy of the Millennium Bylaws may be
obtained from the Secretary of Millennium at the address set forth under 'Where
You Can Find More Information.'
 
                      WHERE YOU CAN FIND MORE INFORMATION
 
     Lyondell and Millennium file annual, quarterly and special reports, proxy
statements and other information with the SEC. You may read and copy any
reports, statements or other information we file at the SEC's public reference
rooms in Washington, District of Columbia, New York, New York and Chicago,
Illinois. Please call the SEC at 1-800-SEC-0330 for further information on the
public reference rooms. Our SEC filings are also available to the public from
commercial document retrieval services and at the web site maintained by the SEC
at 'http://www.sec.gov.'
 
     The SEC allows us to 'incorporate by reference' information into this Joint
Proxy Statement, which means that we can disclose important information to you
by referring you to another document filed separately with the SEC. The
information incorporated by reference is deemed to be part of this Joint Proxy
Statement, except for any information superseded by information in this Joint
Proxy Statement. This Joint Proxy Statement incorporates by reference the
documents set forth below that we have previously filed with the SEC. These
documents contain important information about our companies and their finances.
The complete text of the Master Transaction Agreement was filed as an exhibit to
Lyondell's Current Report on Form 8-K on August 14, 1997 and as an exhibit to
Millennium's Current Report on Form 8-K on August 15, 1997. The complete text of
each of the Partnership Agreement, the Asset Contribution Agreements and the
Parent Agreement was also filed as an exhibit to Current Reports on Form 8-K of
Lyondell and Millennium on                , 1997 and                , 1997,
respectively. If any of these agreements is changed in a significant way prior
to the date of the Lyondell Meeting and the Millennium Meeting, the new version
also will be filed as exhibits to Lyondell's and Millennium's Current Reports on
Form 8-K.
 
<TABLE>
<CAPTION>
LYONDELL SEC FILINGS (FILE NO. 1-10145)              PERIOD COVERED
- ---------------------------------------------------  ---------------------------------------------------
 
<S>                                                  <C>
Annual Report on Form 10-K.........................  Year ended December 31, 1996
Quarterly Reports on Form 10-Q.....................  Quarters ended March 31, 1997 and June 30, 1997
Current Reports on Form 8-K........................  Filed on July 28, 1997 and August 14, 1997
 
MILLENNIUM SEC FILINGS (FILE NO. 1-12091)            PERIOD COVERED
- ---------------------------------------------------  ---------------------------------------------------
Annual Report on Form 10-K.........................  Year ended December 31, 1996
Quarterly Reports on Form 10-Q.....................  Quarters ended March 31, 1997 and June 30, 1997
Current Reports on Form 8-K........................  Filed on July 29, 1997
</TABLE>
 
                                       86
 <PAGE>
<PAGE>
     We are also incorporating by reference additional documents that we file
with the SEC between the date of this Joint Proxy Statement and the respective
dates of the Lyondell Meeting and the Millennium Meeting.
 
     Lyondell has supplied all such information relating to Lyondell and
Millennium has supplied all information relating to Millennium contained or
incorporated by reference in this Joint Proxy Statement.
 
     If you are a stockholder, we may have sent you some of the documents
incorporated by reference, but you can obtain any of them through us or the SEC.
Documents incorporated by reference are available from us without charge,
excluding all exhibits unless we have specifically incorporated by reference an
exhibit in this Joint Proxy Statement. Stockholders may obtain documents
incorporated by reference in this Joint Proxy Statement by requesting them in
writing or by telephone from the appropriate party at the following addresses:
 
<TABLE>
<S>                                  <C>                           <C>
Lyondell Petrochemical Company       Millennium Chemicals Inc.     Millennium Chemicals Inc.
1221 McKinney Street, Suite 1600     99 Wood Avenue South          Laporte Road
Houston, Texas 77010                 P.O. Box 7050                 Stallingborough,
(713) 652-7200                       Iselin, New Jersey 08830      Nr. Grimsby,
                                     (908) 603-6868                North East Lincolnshire
                                                                   DN40 2PR ENGLAND
                                                                   0345 662663
</TABLE>
 
     If you would like to request documents from us, please do so by
               , 1997 to receive them before the Lyondell Meeting or the
Millennium Meeting, as applicable.
 
     YOU SHOULD RELY ON THE INFORMATION CONTAINED OR INCORPORATED BY REFERENCE
IN THIS JOINT PROXY STATEMENT TO VOTE ON THE LYONDELL ASSET CONTRIBUTION OR THE
MILLENNIUM ASSET CONTRIBUTION. WE HAVE NOT AUTHORIZED ANYONE TO PROVIDE YOU WITH
INFORMATION THAT IS DIFFERENT FROM WHAT IS CONTAINED IN THIS JOINT PROXY
STATEMENT. THIS JOINT PROXY STATEMENT IS DATED                , 1997. YOU SHOULD
NOT ASSUME THAT THE INFORMATION CONTAINED IN THE JOINT PROXY STATEMENT IS
ACCURATE AS OF ANY DATE OTHER THAN SUCH DATE, AND THE MAILING OF THE JOINT PROXY
STATEMENT TO STOCKHOLDERS SHALL NOT CREATE ANY IMPLICATION TO THE CONTRARY.
 
                                 OTHER MATTERS
 
     As of the date of this Joint Proxy Statement, neither the Board of
Directors of Lyondell nor the Board of Directors of Millennium intends to
present, nor has either Board been informed that any other person intends to
present, any matter for action at the Lyondell Meeting or the Millennium
Meeting, as the case may be, other than as specifically discussed herein.
 
                                       87
<PAGE>
<PAGE>
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<S>                                                                                                           <C>
LYONDELL CONTRIBUTED BUSINESS
Report of Coopers & Lybrand L.L.P. ........................................................................    F-2
Balance Sheets -- June 30, 1997, December 31, 1996 and 1995................................................    F-3
Statements of Income and Invested Capital -- Six Months Ended June 30, 1997 and 1996, Years Ended December
  31, 1996, 1995 and 1994..................................................................................    F-4
Statements of Cash Flows -- Six Months Ended June 30, 1997 and 1996, Years Ended December 31, 1996, 1995
  and 1994.................................................................................................    F-5
Notes to Financial Statements..............................................................................    F-6
 
MILLENNIUM CONTRIBUTED BUSINESS
Report of Price Waterhouse LLP.............................................................................   F-14
Balance Sheets -- June 30, 1997, December 31, 1996 and 1995................................................   F-15
Statements of Income -- Six Months Ended June 30, 1997 and 1996, Years Ended December 31, 1996, 1995 and
  1994.....................................................................................................   F-16
Statements of Changes in Invested Capital -- Six Months Ended June 30, 1997, Years Ended December 31, 1996,
  1995 and 1994............................................................................................   F-17
Statements of Cash Flows -- Six Months Ended June 30, 1997 and 1996, Years Ended December 31, 1996, 1995
  and 1994.................................................................................................   F-18
Notes to Financial Statements..............................................................................   F-19
</TABLE>
 
                                      F-1
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Stockholders and Board of Directors of
LYONDELL PETROCHEMICAL COMPANY:
 
     We have audited the accompanying balance sheets of the contributed
petrochemicals and polymers businesses of Lyondell Petrochemical Company
('Lyondell Contributed Business') as of December 31, 1996 and 1995, and the
related statements of income and invested capital, and cash flows for each of
the three years in the period ended December 31, 1996. These financial
statements are the responsibility of the Lyondell Contributed Business's
management. Our responsibility is to express an opinion on these financial
statements based on our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of the Lyondell Contributed
Business as of December 31, 1996 and 1995, and the results of its operations and
its cash flows for each of the three years in the period ended December 31, 1996
in conformity with generally accepted accounting principles.
 
COOPERS & LYBRAND L.L.P.
Houston, Texas
August 29, 1997
 
                                      F-2
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                                 BALANCE SHEETS
 
<TABLE>
<CAPTION>
                                                                                                    DECEMBER 31,
                                                                                   JUNE 30,     ---------------------
                                                                                     1997         1996       1995
                                                                                  -----------    -------    -------
                                                                                  (UNAUDITED)
                                                                                            (IN MILLIONS)
 
<S>                                                                               <C>            <C>        <C>
                                    ASSETS
Current assets:
     Accounts receivable:
          Trade................................................................     $   301      $   259    $   215
          Related parties......................................................          49           96         45
     Inventories...............................................................         206          196        159
     Prepaid expenses and other current assets.................................          12           10         13
                                                                                  -----------    -------    -------
               Total current assets............................................         568          561        432
                                                                                  -----------    -------    -------
Property, plant and equipment..................................................       1,995        1,969      1,896
Less accumulated depreciation and amortization.................................      (1,161)      (1,129)    (1,078)
                                                                                  -----------    -------    -------
                                                                                        834          840        818
 
Deferred charges and other assets..............................................         102           93         56
                                                                                  -----------    -------    -------
               Total assets....................................................     $ 1,504      $ 1,494    $ 1,306
                                                                                  -----------    -------    -------
                                                                                  -----------    -------    -------
 
                       LIABILITIES AND INVESTED CAPITAL
Current liabilities:
     Accounts payable:
          Trade................................................................     $   135      $   200    $   127
          Related parties......................................................          19           30         20
     Current maturities of long-term debt......................................           2           --        150
     Other accrued liabilities.................................................          52           62         66
                                                                                  -----------    -------    -------
               Total current liabilities.......................................         208          292        363
                                                                                  -----------    -------    -------
Long-term debt.................................................................         743          745        595
Other liabilities and deferred credits.........................................          36           34         28
Commitments and contingencies (Note 9)
 
Invested capital...............................................................         517          423        320
                                                                                  -----------    -------    -------
               Total liabilities and invested capital..........................     $ 1,504      $ 1,494    $ 1,306
                                                                                  -----------    -------    -------
                                                                                  -----------    -------    -------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-3
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                   STATEMENTS OF INCOME AND INVESTED CAPITAL
 
<TABLE>
<CAPTION>
                                                                  FOR THE SIX MONTHS             FOR THE YEAR
                                                                    ENDED JUNE 30,            ENDED DECEMBER 31,
                                                                ----------------------    --------------------------
                                                                   1997         1996       1996      1995      1994
                                                                ----------    --------    ------    ------    ------
                                                                     (UNAUDITED)
                                                                                   (IN MILLIONS)
 
<S>                                                             <C>           <C>         <C>       <C>       <C>
Sales and other operating revenues:
     Unrelated parties.......................................     $1,162       $  912     $2,002    $2,025    $1,344
     Related parties.........................................        287          222        513       484       462
                                                                ----------    --------    ------    ------    ------
                                                                   1,449        1,134      2,515     2,509     1,806
Operating costs and expenses:
     Cost of sales:
          Unrelated parties..................................        915          769      1,659     1,491     1,075
          Related parties....................................        219          195        409       332       339
     Depreciation and amortization...........................         41           29         67        46        35
     Selling, general and administrative expenses............         80           76        157       125        69
                                                                ----------    --------    ------    ------    ------
                                                                   1,255        1,069      2,292     1,994     1,518
                                                                ----------    --------    ------    ------    ------
     Operating income........................................        194           65        223       515       288
Interest expense.............................................         35           36         65        76        73
                                                                ----------    --------    ------    ------    ------
     Income before income taxes..............................        159           29        158       439       215
Provision for income taxes...................................         58           10         56       162        78
                                                                ----------    --------    ------    ------    ------
     Net income..............................................        101           19        102       277       137
Invested capital at beginning of period......................        423          320        320       (87)     (261)
Net transactions with Lyondell...............................         (7)          74          1       130        37
                                                                ----------    --------    ------    ------    ------
Invested capital at end of period............................     $  517       $  413     $  423    $  320    $  (87)
                                                                ----------    --------    ------    ------    ------
                                                                ----------    --------    ------    ------    ------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-4
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                            STATEMENTS OF CASH FLOWS

<TABLE>
<CAPTION>
                                                  FOR THE SIX
                                                     MONTHS              FOR THE YEAR
                                                 ENDED JUNE 30,       ENDED DECEMBER 31,
                                                ----------------    -----------------------
                                                1997       1996     1996     1995     1994
                                                ----       -----    -----    -----    -----
                                                  (UNAUDITED)  (IN MILLIONS)
 
<S>                                             <C>        <C>      <C>      <C>      <C>
Cash flows from operating activities:
     Net income..............................   $101       $  19    $ 102    $ 277    $ 137
     Adjustments to reconcile net income to
       net cash provided by (used in)
       operating activities:
          Depreciation and amortization......     41          29       67       46       35
          Decrease (increase) in accounts
            receivable.......................      5         (30)     (95)      26     (134)
          Increase in inventories............    (10)        (44)     (37)     (40)     (42)
          Increase (decrease) in accounts
            payable..........................    (76)         44       83       13       40
          Net change in other working capital
            accounts.........................    (12)        (24)      (1)      10       (9)
          Other..............................    (14)        (26)     (40)     (14)     (16)
                                                ----       -----    -----    -----    -----
               Net cash provided by (used in)
                 operating activities........     35         (32)      79      318       11
Cash flows from investing activities:
     Additions to property, plant and
       equipment.............................    (28)        (42)     (80)    (476)     (40)
                                                ----       -----    -----    -----    -----
               Net cash (used in) investing
                 activities..................    (28)        (42)     (80)    (476)     (40)
 
Cash flows from financing activities:
     Net transactions with Lyondell..........     (7)         74        1      130       37
     Borrowings of long-term debt............    --          300      300       38     --
     Repayments of long-term debt............    --         (300)    (300)     (10)      (8)
                                                ----       -----    -----    -----    -----
               Net cash provided by (used in)
                 financing activities........     (7)         74        1      158       29
                                                ----       -----    -----    -----    -----
Net change in cash and cash equivalents......   $--        $--      $--      $--      $--
                                                ----       -----    -----    -----    -----
                                                ----       -----    -----    -----    -----
</TABLE>
  
                                      F-5
<PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                         NOTES TO FINANCIAL STATEMENTS
                                 (IN MILLIONS)
 
NOTE 1. BASIS OF PRESENTATION AND DESCRIPTION OF THE CONTRIBUTED BUSINESS
 
     On July 28, 1997, Lyondell Petrochemical Company ('Lyondell' or the
'Company') and Millennium Chemicals Inc. ('Millennium') announced an agreement
to form a new joint venture company which will be operated as a partnership (the
'Partnership'). The Partnership, which will be owned 57% by the Company and 43%
by Millennium, will own and operate the existing olefins and polymers businesses
to be contributed by the two companies. The assets of the Partnership will
consist of 13 manufacturing facilities on the US Gulf Coast and in the US
Midwest, producing ethylene, propylene, polyethylene (high-density, low-density
and linear low-density), polypropylene, ethyl alcohol, butadiene, aromatics,
methyl tertiary butyl ether ('MTBE') and other products for sale to customers
located throughout the US. The Partnership is expected to have $1.745 billion of
debt, including $745 face value of debt assumed from Lyondell and $750 under a
new credit facility, the proceeds of which will be used to repay debt assumed
from Millennium upon completion of the transaction, and a note receivable from
Lyondell of $345.
 
     Lyondell will contribute to the Partnership substantially all of the net
assets and operations comprising its petrochemicals and polymers segments.
Lyondell will retain ownership of its approximately 60% interest in
LYONDELL-CITGO Refining Company Ltd. ('LYONDELL-CITGO Refining') and its 75%
interest in Lyondell Methanol Company, L.P. ('Lyondell Methanol').
 
     The accompanying financial statements include the results of operations,
assets and liabilities of the petrochemicals and polymers businesses currently
owned by Lyondell that will be contributed to the Partnership (the 'Contributed
Business'). These financial statements are presented on a going concern basis
and include only the historical net assets and results of operations that are
directly related to the Contributed Business. Consequently, the financial
position, results of operations and cash flows may not be indicative of what
would have been reported if the Contributed Business had been a separate, stand-
alone entity or had been operated as a part of the Partnership.
 
     Lyondell provided certain corporate, general and administrative services to
the Contributed Business, including legal, tax, treasury, risk management and
other services. The Contributed Business provided certain general and
administrative services to Lyondell, including computer, office lease and
employee benefits services. Charges for such services are believed to be
reasonable and substantially offset each other for the periods presented. In
addition, Lyondell has controlled, on a centralized basis, all cash receipts and
disbursements received or made by the Contributed Business. The net results of
such transactions are included in the balance sheets as invested capital.
 
     The accompanying financial statements as of June 30, 1997 and 1996 and all
references made to amounts for the periods then ended are unaudited and have
been prepared in accordance with the rules and regulations of the Securities and
Exchange Commission. In the opinion of management, all adjustments, consisting
only of normal, recurring adjustments considered necessary for a fair
presentation of the results of operations and financial position of the
Contributed Business for the interim periods presented, have been included.
 
NOTE 2. SIGNIFICANT ACCOUNTING POLICIES
 
     Revenue Recognition. Revenue from product sales is generally recognized
upon delivery of product to the customer.
 
     Use of Estimates. The preparation of financial statements in conformity
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts of assets and
liabilities at the date of the financial statements and the reported amount of
revenues and expenses during the reporting period. Actual results could differ
from those estimates.
 
     Accounts Receivable. The Contributed Business sells its products primarily
to companies in the petrochemicals and polymers industries. The Contributed
Business's allowance for doubtful accounts,
 
                                      F-6
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
which is reflected in the balance sheet as a reduction of accounts receivable,
totaled $3 at June 30, 1997, December 31, 1996 and 1995.
 
     Inventories. Inventories are stated at the lower of cost or market value.
Cost is determined on the last-in, first-out ('LIFO') basis, except for
materials and supplies, which are valued at average cost. Inventories valued on
a LIFO basis were approximately $51, $46, and $15 less than the amount of such
inventories valued at current cost at June 30, 1997, December 31, 1996 and 1995,
respectively.
 
     Inventories consist of the following:
 
<TABLE>
<CAPTION>
                                                                                             DECEMBER 31,
                                                                               JUNE 30,      ------------
                                                                                 1997        1996    1995
                                                                              -----------    ----    ----
                                                                              (UNAUDITED)
<S>                                                                           <C>            <C>     <C>
Petrochemicals.............................................................      $ 113       $ 98    $ 77
Polymers...................................................................         68         74      58
Materials and supplies.....................................................         25         24      24
                                                                                 ------      ----    ----
                                                                                 $ 206       $196    $159
                                                                                 ------      ----    ----
                                                                                 ------      ----    ----
</TABLE>
 
     Property, Plant and Equipment. Property, plant and equipment are recorded
at cost. Depreciation of property, plant and equipment is computed using the
straight-line method over the estimated useful lives of the assets, generally 5
to 30 years for manufacturing facilities and equipment. Interest cost incurred
on debt during the construction of major projects that exceed one year is
capitalized. No interest was capitalized during the periods presented. Property,
plant and equipment consists of the following:
 
<TABLE>
<CAPTION>
                                                                                           DECEMBER 31,
                                                                           JUNE 30,      ----------------
                                                                             1997         1996      1995
                                                                          -----------    ------    ------
                                                                          (UNAUDITED)
 
<S>                                                                       <C>            <C>       <C>
Manufacturing facilities and equipment.................................     $ 1,883      $1,822    $1,728
Construction projects in progress......................................          85         120       143
Land...................................................................          27          27        25
                                                                          -----------    ------    ------
                                                                            $ 1,995      $1,969    $1,896
                                                                          -----------    ------    ------
                                                                          -----------    ------    ------
</TABLE>
 
     Turnaround Maintenance and Repair Expenses. The cost of repairs and
maintenance incurred in connection with turnarounds of major units at the
Contributed Business's manufacturing facilities exceeding $5 are deferred as
incurred and amortized on a straight line basis until the next planned
turnaround, which is generally four to six years.
 
     Repair and maintenance expense is comprised of the following:
 
<TABLE>
<CAPTION>
                                                                          FOR THE SIX MONTHS                   FOR THE YEAR
                                                                                ENDED                             ENDED
                                                                               JUNE 30,                        DECEMBER 31,
                                                               ----------------------------------------    --------------------
                                                                      1997                  1996           1996    1995    1994
                                                                      ----                  ----           ----    ----    ----
                                                                             (UNAUDITED)
 
<S>                                                            <C>                   <C>                   <C>     <C>     <C>
Repair and maintenance expense..............................          $ 24                  $ 21            $58     $55     $37
Amortization of deferred turnaround costs...................             5                     2              7       1       4
                                                                      ----                  ----           ----    ----    ----
                                                                      $ 29                  $ 23            $65     $56     $41
                                                                      ----                  ----           ----    ----    ----
                                                                      ----                  ----           ----    ----    ----
</TABLE>
 
                                      F-7
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
     Other Accrued Liabilities. Other accrued liabilities consist of the
following:
 
<TABLE>
<CAPTION>
                                                                                              DECEMBER 31,
                                                                               JUNE 30,      -------------
                                                                                 1997        1996     1995
                                                                              -----------    ----     ----
                                                                              (UNAUDITED)
 
<S>                                                                           <C>            <C>      <C>
Payroll....................................................................       $18         $20      $26
Interest...................................................................        15          15       11
Taxes other than income....................................................        12          20       22
Other......................................................................         7           7        7
                                                                                  ---        -----    -----
     Total.................................................................       $52         $62      $66
                                                                                  ---        -----    -----
                                                                                  ---        -----    -----
</TABLE>
 
     Accounts payable and certain accrued expenses are not being contributed to
the Partnership at its formation.
 
     Environmental Remediation Costs. Expenditures related to investigation and
remediation of contaminated sites, which include operating facilities and waste
disposal sites, are accrued when it is probable a liability has been incurred
and the amount of the liability can reasonably be estimated. Accrued liabilities
are exclusive of claims against third parties (except where payment has been
received or the amount of liability or contribution by such other parties,
including insurance companies, has been agreed) and are not discounted. In
general, costs related to environmental remediation are charged to expense.
Environmental costs are capitalized if the costs increase the value of the
property and/or mitigate or prevent contamination from future operations.
 
     Exchanges. Finished product exchange transactions, which are of a
homogeneous nature of commodities in the same line of business and do not
involve the payment or receipt of cash, are not accounted for as purchases and
sales. Any resulting volumetric exchange balances are accounted for as inventory
in accordance with the normal LIFO valuation policy. Exchanges settled through
payment and receipt of cash are accounted for as purchases and sales.
 
     Income Taxes. Earnings of the Contributed Business have been included in
the consolidated income tax returns filed by Lyondell. Pursuant to an informal
tax allocation agreement, income taxes have been allocated to the Contributed
Business based on applicable statutory tax rates applied to the taxable earnings
generated by such business. The effective income tax rates were 36.4%, 36.4%,
35.7%, 36.8% and 36.2% for the six months ended June 30, 1997 and 1996 and the
years ended December 31, 1996, 1995 and 1994, respectively. State income tax was
the primary difference between the effective tax rates and the 35% federal
statutory rate. Liabilities for current and/or deferred income taxes have been
and remain the responsibility of Lyondell and, accordingly, have been included
in the balance sheet as invested capital.
 
     As part of the transactions to consummate the Partnership, Lyondell will
enter into tax sharing and indemnification agreements with the Partnership in
which Lyondell will generally agree to indemnify the Partnership for income tax
liabilities attributable to periods when the earnings of the Contributed
Business were included in the consolidated tax return of Lyondell.
 
     Research and Development. The cost of research and development efforts is
expensed as incurred. Such costs aggregated $6, $6, $13, $5 and $1 for the six
months ended June 30, 1997 and 1996 and the years ended December 31, 1996, 1995
and 1994, respectively.
 
     Earnings Per Share. Historical earnings per share are not presented because
there is no separate identifiable pool of capital upon which a per share
calculation could be based.
 
NOTE 3. ACQUISITION OF ALATHON'r' HIGH-DENSITY POLYETHYLENE BUSINESS
 
     In May 1995, the Company acquired Occidental Chemical Corporation's
Alathon'r' (high-density polyethylene ('HDPE') business ('ALATHON Business') for
$356 including certain direct costs, plus
 
                                      F-8
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
approximately $64 for inventory. Assets involved in the purchase included resin
production facilities at Victoria and Matagorda, Texas, associated research and
development activities and the rights to the Alathon'r' trademark. These
facilities have a combined annual production capacity of approximately 1.5
billion pounds of HDPE. The Company financed the acquisition from internal cash
and $230 of short-term borrowings from its existing financing arrangements.
 
     The following unaudited pro forma information combines the results of
operations of the Contributed Business and the ALATHON Business for the years
ended December 31, 1995 and 1994 and assumes the acquisition of the ALATHON
Business occurred on January 1, 1994. This unaudited pro forma information may
not be indicative of results that would have actually resulted if this
transaction had occurred on January 1, 1994 or which may be obtained in the
future.
 
<TABLE>
<CAPTION>
                                                                                 1995                     1994
                                                                         ---------------------    ---------------------
 
<S>                                                                      <C>                      <C>
Sales and other operating revenues....................................          $ 2,703                  $ 2,238
Net income............................................................              297                      154
</TABLE>
 
NOTE 4. FINANCIAL INSTRUMENTS
 
     The fair value of all financial instruments included in current assets and
current liabilities, including accounts receivable, accounts payable and notes
payable, approximated their carrying value due to their short maturity. Based on
the borrowing rates currently available to the Contributed Business for debt
with terms and average maturities similar to the Contributed Business's debt
portfolio, the fair value of the Contributed Business's long-term debt,
including amounts due within one year, was $656, $661 and $804 at June 30, 1997
and December 31, 1996 and 1995, respectively.
 
     The Contributed Business is party to various unconditional purchase
obligation contracts as a purchaser for product and services. At December 31,
1996, future minimum payments under these contracts with noncancelable contract
terms in excess of one year were as follows:
 
<TABLE>
<CAPTION>
                                                                         AMOUNT
                                                                  ---------------------
 
<S>                                                               <C>
1997...........................................................           $  16
1998...........................................................              14
1999...........................................................              14
2000...........................................................              13
2001...........................................................              11
Thereafter.....................................................              64
                                                                         ------
     Total minimum contract payments...........................           $ 132
                                                                         ------
                                                                         ------
</TABLE>
 
     The Contributed Business's total purchases under these agreements were $8,
$9, $17 and $13 for the six months ended June 30, 1997 and 1996 and the years
ended December 31, 1996 and 1995, respectively.
 
                                      F-9
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
NOTE 5. RELATED PARTY TRANSACTIONS
 
     Related party transactions with Atlantic Richfield Company ('ARCO'),
excluding sales to ARCO Chemical Company, and LYONDELL-CITGO Refining are as
follows:
 
<TABLE>
<CAPTION>
                                                           FOR THE SIX MONTHS             FOR THE YEAR
                                                                  ENDED                      ENDED
                                                                JUNE 30,                  DECEMBER 31,
                                                       ---------------------------    --------------------
                                                          1997            1996        1996    1995    1994
                                                       -----------    ------------    ----    ----    ----
                                                               (UNAUDITED)
 
<S>                                                    <C>            <C>             <C>     <C>     <C>
Sales:
     Products.......................................      $ 145           $ 88        $198    $162    $159
     Other..........................................          7              6          12      16      16
     Business interruption recovery.................        --             --           25     --      --
                                                          -----            ---        ----    ----    ----
                                                          $ 152           $ 94        $235    $178    $175
                                                          -----            ---        ----    ----    ----
                                                          -----            ---        ----    ----    ----
Costs:
     Product purchases..............................      $ 105           $ 82        $182    $283    $417
     Transportation fees............................         13             12          23      21      22
     Other, net.....................................         (5)            (5)         (9)     (7)     (7)
     Business interruption recovery.................        --             --           (3)    --      --
                                                          -----            ---        ----    ----    ----
                                                          $ 113           $ 89        $193    $297    $432
                                                          -----            ---        ----    ----    ----
                                                          -----            ---        ----    ----    ----
</TABLE>
 
     Sales to ARCO Chemical Company, an ARCO affiliate, consisting primarily of
product sales, were $135, $128, $278, $306 and $287 for the six months ended
June 30, 1997 and 1996 and the years ended December 31, 1996, 1995 and 1994,
respectively.
 
     In July of 1996 a fire occurred at the ARCO PipeLine Company meter station
located within the Channelview, Texas petrochemicals facility ('Channelview
Facility'). The fire forced the shutdown of the entire Channelview Facility for
several days and more than two weeks for some units. The Contributed Business
recovered lost profits from ARCO PipeLine Company for this shutdown. The
recovery was included in 1996 reported results.
 
NOTE 6. LONG-TERM DEBT
 
     Long-term debt consists of the following:
 
<TABLE>
<CAPTION>
                                                                                   DECEMBER 31,
                                                                     JUNE 30,      ------------
                                                                       1997        1996    1995
                                                                    -----------    ----    ----         
                                                                    (UNAUDITED)
 
<S>                                                                 <C>            <C>     <C>
10.00% Notes due in 1999.........................................      $ 150       $150    $150
9.125% Notes due in 2002.........................................        100        100     100
6.5% Notes due in 2006...........................................        150        150     --
7.55% Debentures due in 2026.....................................        150        150     --
9.95% Notes due in 1996..........................................      --           --      150
Medium-term notes (1998 -- 2005).................................        195        195     207
Other............................................................      --           --      138
                                                                    -----------    ----    ----
                                                                         745        745     745
Less current portion.............................................         (2)       --     (150)
                                                                    -----------    ----    ----
                                                                       $ 743       $745    $595
                                                                    -----------    ----    ----
                                                                    -----------    ----    ----
</TABLE>
 
     Aggregate maturities of long-term debt during the five years subsequent to
December 31, 1996 are as follows: 1997 -- none; 1998 -- $32; 1999 -- $150;
2000 -- $42; 2001 -- $90. After contribution to the Partnership, Lyondell will
continue to be liable on the above debt until its maturity.
 
                                      F-10
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
     The Notes due in 1999 and the medium-term notes contain provisions that
would allow the holders to require the Company to repurchase the debt upon the
occurrence of certain events together with specified declines in public ratings
on the Notes due in 1999. Certain events include acquisitions by persons other
than ARCO or the Company of more than 20% of the Company's common stock, any
merger or transfer of substantially all of the Company's assets, in connection
with which the Company's common stock is changed into or exchanged for cash,
securities or other property, and payment of certain 'special' dividends.
 
     The medium-term notes mature at various dates from 1998 to 2005 and have a
weighted average interest rate at June 30, 1997, December 31, 1996 and 1995 of
9.8%, 9.8% and 9.9%, respectively.
 
     Interest paid was $35, $32, $61, $75 and $73 for the six months ended June
30, 1997 and 1996 and the years ended December 31, 1996, 1995 and 1994,
respectively.
 
NOTE 7. PENSION AND OTHER POSTRETIREMENT BENEFITS
 
     Defined Benefit Pension Plans -- All full-time regular employees of the
Contributed Business are covered by defined benefit pension plans sponsored by
Lyondell. Retirement benefits are based on years of service and the employee's
highest three consecutive years of compensation during the last ten years of
service. The funding policy for these plans is to make periodic contributions as
required by applicable law. The Contributed Business accrues pension costs based
on an actuarial valuation and funds the plans through contributions to the
Company, reflected in invested capital, which then contributes to pension trust
funds separate from Lyondell funds. The Contributed Business also has unfunded
supplemental nonqualified retirement plans which provide pension benefits for
certain employees in excess of the tax qualified plans' limits. The Contributed
Business recorded expense related to participation in these plans of $4, $3, $7,
$4 and $6 for the six months ended June 30, 1997 and 1996 and the years ended
December 31, 1996, 1995 and 1994, respectively.
 
     Defined Contribution Plans -- Effective July 1, 1995, Lyondell also
maintains voluntary defined contribution savings plans for eligible employees,
including those employed by the Contributed Business. Under provisions of the
plans, Lyondell contributes an amount equal to 160% of employee contributions up
to a maximum matching contribution of eight percent of the employee's base
salary. Prior to July 1, 1995, Lyondell had similar voluntary defined
contribution plans. The Contributed Business recorded expense related to
participation in these voluntary defined contribution savings plans totaling $3,
$3, $6, $5 and $4 for the six months ended June 30, 1997 and 1996 and the years
ended December 31, 1996, 1995 and 1994, respectively.
 
     Other Postretirement Benefit Plans -- Lyondell sponsors unfunded
postretirement benefit plans other than pensions ('OPEB') for both salaried and
non-salaried employees, including those employed by the Contributed Business,
which provide medical and life insurance benefits. The postretirement health
care plans are contributory while the life insurance plans are non-contributory.
Currently, Lyondell pays approximately 80% of the cost of the health care plans,
but reserves the right to modify the cost-sharing provisions at any time. The
Contributed Business recorded expense related to participation in these plans of
approximately $2, $2, $4, $2 and $2 for the six months ended June 30, 1997 and
1996 and the years ended December 31, 1996, 1995 and 1994, respectively. The
actuarially determined liability associated with the currently active employees
of the Contributed Business based on current plan provisions at December 31,
1996 was $22.
 
                                      F-11
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
NOTE 8. LEASES
 
     At December 31, 1996, future minimum rental payments for operating leases
with noncancelable lease terms in excess of one year were as follows:
 
<TABLE>
<CAPTION>
                                                                             AMOUNT
                                                                             ------
 
<S>                                                                          <C>
1997......................................................................    $ 43
1998......................................................................      40
1999......................................................................      29
2000......................................................................      25
2001......................................................................      23
Thereafter................................................................     367
                                                                             ------
     Total minimum contract payments......................................    $527
                                                                             ------
                                                                             ------
</TABLE>
 
     Operating lease net rental expenses were $25, $27, $44, $39 and $29 for the
six months ended June 30, 1997 and 1996 and the years ended December 31, 1996,
1995 and 1994, respectively.
 
NOTE 9. COMMITMENTS AND CONTINGENCIES
 
     The Contributed Business has various purchase commitments for materials,
supplies and services incident to the ordinary conduct of business. In the
aggregate, such commitments are not at prices in excess of current market.
 
     In connection with the transfer of assets and liabilities from ARCO to the
Company, the Company and ARCO entered into an agreement ('Cross-Indemnity
Agreement') whereby the Company agreed to defend and indemnify ARCO against
certain uninsured claims and liabilities which ARCO may incur relating to the
operation of the Company's integrated petrochemicals and petroleum processing
business prior to July 1, 1988, including certain liabilities which may arise
out of pending and future lawsuits. ARCO indemnified the Company under the
Cross-Indemnity Agreement with respect to other claims or liabilities and other
matters of litigation not related to the assets or business included in the
Company's consolidated financial statements. The Company has reached an
agreement-in-principle with ARCO to update the Cross-Indemnity Agreement
('Revised Cross-Indemnity Agreement'). The Cross-Indemnity Agreement and the
Revised Cross-Indemnity Agreement cover operations of the Company included in
the Contributed Business. Subject to the uncertainty inherent in all litigation,
management believes the resolution of the matters pursuant to the Revised
Cross-Indemnity Agreement will not have a material adverse effect upon the
financial statements or liquidity of the Contributed Business.
 
     In addition to lawsuits for which the Company has indemnified ARCO, the
Company is also subject to various lawsuits and proceedings which may involve
the operations of the Contributed Business. Subject to the uncertainty inherent
in all litigation, management believes the resolution of these proceedings will
not have a material adverse effect upon the financial statements or liquidity of
the Contributed Business.
 
     As part of the transactions to consummate the Partnership, Lyondell will
agree to indemnify the Partnership for any present or future liabilities arising
within a seven-year period after the consummation of the partnership which are
attributable to the Contributed Business operations prior to the Partnership's
formation in excess of $7.
 
     The Contributed Business's policy is to be in compliance with all
applicable environmental laws. The Contributed Business is subject to extensive
environmental laws and regulations concerning emissions to the air, discharges
to surface and subsurface waters and the generation, handling, storage,
transportation, treatment and disposal of waste materials. Some of these laws
and regulations are subject to varying and conflicting interpretations. In
addition, the Contributed Business cannot
 
                                      F-12
 <PAGE>
<PAGE>
                         LYONDELL CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
accurately predict future developments, such as increasingly strict requirements
of environmental laws, inspection and enforcement policies and compliance costs
therefrom which might affect the handling, manufacture, use, emission or
disposal of products, other materials or hazardous and non-hazardous waste.
 
     As of June 30, 1997 and December 31, 1996, the Contributed Business has
accrued $3 related to future regulatory agency assessment and remediation costs,
of which $2 is included in current liabilities at June 30, 1997 while the
remaining amounts are expected to be incurred over the next two to seven years.
In the opinion of management, there is currently no material range of loss in
excess of the amount recorded. However, it is possible that new information
about the sites for which the reserve has been established, new technology or
future developments such as involvement in other regulatory agency or other
comparable state law investigations, could require the Contributed Business to
reassess its potential exposure related to environmental matters.
 
     In the opinion of management, any liability arising from the matters
discussed in this Note will not have a material adverse effect on the financial
statements or liquidity of the Contributed Business. However, the adverse
resolution in any reporting period of one or more of these matters discussed in
this Note could have a material impact on the Contributed Business's results of
operations for that period without giving effect to contribution or
indemnification obligations of co-defendants or others, or to the effect of any
insurance coverage that may be available to offset the effects of any such
award.
 
                                      F-13
<PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                       REPORT OF INDEPENDENT ACCOUNTANTS
 
To the Board of Directors and Shareholders of
MILLENNIUM CHEMICALS INC.
 
     We have audited the accompanying balance sheets of Millennium Contributed
Business as of December 31, 1996 and 1995, and the related statements of income,
of cash flows and of changes in invested capital for each of the three years in
the period ended December 31, 1996. These financial statements are the
responsibility of the management of the Millennium Contributed Business. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
     We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
     In our opinion, the financial statements audited by us present fairly, in
all material respects, the financial position of the Millennium Contributed
Business as of December 31, 1996 and 1995, and the results of its operations and
its cash flows for each of the three years in the period ended December 31, 1996
in conformity with generally accepted accounting principles.
 
PRICE WATERHOUSE LLP
Morristown, New Jersey
September 2, 1997
 
                                      F-14
<PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                                 BALANCE SHEETS
 
<TABLE>
<CAPTION>
                                                                                                          DECEMBER 31,
                                                                                   JUNE 30,       ----------------------------
                                                                                     1997             1996            1995
                                                                                  -----------     ------------    ------------
                                                                                  (UNAUDITED)    (IN MILLIONS)
 
<S>                                                                               <C>             <C>             <C>
                                    ASSETS
Current assets:
     Accounts receivable -- net................................................     $   285          $     269       $     216
     Inventories...............................................................         239                294             279
     Prepaid expenses and other current assets.................................          16                 25              19
                                                                                  -----------     ------------    ------------
          Total current assets.................................................         540                588             514
Property, plant and equipment -- net...........................................       1,305              1,335           1,237
Other non-current assets:
     Other assets..............................................................          27                 27              24
     Goodwill..................................................................       1,155              1,171           1,202
                                                                                  -----------     ------------    ------------
          Total assets.........................................................     $ 3,027          $   3,121       $   2,977
                                                                                  -----------     ------------    ------------
                                                                                  -----------     ------------    ------------
 
                       LIABILITIES AND INVESTED CAPITAL
Current liabilities:
     Current maturities of long-term debt......................................     $     2          $       4       $       4
     Accounts payable..........................................................          64                 53              60
     Accrued expenses and other liabilities....................................         106                168             119
                                                                                  -----------     ------------    ------------
          Total current liabilities............................................         172                225             183
Non-current liabilities:
     Long-term debt............................................................           2                  5               9
     Indebtedness to Millennium................................................       1,000              1,000           1,000
     Other liabilities.........................................................          45                 56              93
                                                                                  -----------     ------------    ------------
          Total liabilities....................................................       1,219              1,286           1,285
                                                                                  -----------     ------------    ------------
Commitments and contingencies (Note 5)
Invested capital...............................................................       1,808              1,835           1,692
                                                                                  -----------     ------------    ------------
          Total liabilities and invested capital...............................     $ 3,027          $   3,121       $   2,977
                                                                                  -----------     ------------    ------------
                                                                                  -----------     ------------    ------------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-15
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                              STATEMENTS OF INCOME
 
<TABLE>
<CAPTION>                                                                  SIX MONTHS ENDED                     YEAR ENDED
                                                                               JUNE 30,                         DECEMBER 31,
                                                                 ------------------------------------    --------------------------
                                                                       1997                1996           1996      1995      1994
                                                                 ----------------    ----------------    ------    ------    ------
                                                                             (UNAUDITED)
                                                                                               (IN MILLIONS)
<S>                                                              <C>                 <C>                 <C>       <C>       <C>
Sales.........................................................        $1,011               $885          $1,860    $1,932    $1,645
 
Cost of sales.................................................           743                682           1,381     1,199     1,202
 
Depreciation and amortization.................................            66                 61             122       125       129
 
Selling, development and administrative expenses..............            53                 55             109       113       104
                                                                     -------             ------          ------    ------    ------
 
     Operating income.........................................           149                 87             248       495       210
 
Interest expense primarily to Millennium......................            40                 40              80        80        80
                                                                     -------             ------          ------    ------    ------
 
Income before income taxes....................................           109                 47             168       415       130
 
Provision for income taxes....................................            48                 26              76       172        62
                                                                     -------             ------          ------    ------    ------
 
Net income....................................................        $   61               $ 21          $   92    $  243    $   68
                                                                     -------             ------          ------    ------    ------
                                                                     -------             ------          ------    ------    ------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-16
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                   STATEMENTS OF CHANGES IN INVESTED CAPITAL
 
<TABLE>
<CAPTION>
                                                                                                       (IN MILLIONS)
 
<S>                                                                                                    <C>
Balance at December 31, 1993........................................................................      $ 1,649
Net income..........................................................................................           68
Net transactions with Millennium....................................................................          (84)
                                                                                                       -------------
Balance at December 31, 1994........................................................................        1,633
Net income..........................................................................................          243
Net transactions with Millennium....................................................................         (184)
                                                                                                       -------------
Balance at December 31, 1995........................................................................        1,692
Net income..........................................................................................           92
Net transactions with Millennium....................................................................           51
                                                                                                       -------------
Balance at December 31, 1996........................................................................        1,835
Net income (unaudited)..............................................................................           61
Net transactions with Millennium (unaudited)........................................................          (88)
                                                                                                       -------------
Balance at June 30, 1997 (unaudited)................................................................      $ 1,808
                                                                                                       -------------
                                                                                                       -------------
</TABLE>
 
                       See notes to financial statements.
 
                                      F-17
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                            STATEMENTS OF CASH FLOWS
 
<TABLE>
<CAPTION>
                                                                            SIX MONTHS                       YEAR ENDED
                                                                          ENDED JUNE 30,                    DECEMBER 31,
                                                                 --------------------------------     ------------------------
                                                                      1997              1996          1996      1995      1994
                                                                 --------------    --------------     -----     -----     ----
                                                                           (UNAUDITED)
                                                                                          (IN MILLIONS)
 
<S>                                                              <C>               <C>                <C>       <C>       <C>
Cash flows from operating activities:
     Net income...............................................        $ 61             $   21         $  92     $ 243     $ 68
     Adjustments to reconcile net income to net cash provided
       by operating activities:
          Depreciation and amortization.......................          66                 61           122       125      129
          (Increase) decrease in accounts receivable..........         (16)               (47)          (53)       32      (54)
          Decrease (increase) in inventories..................          55                 57           (15)      (42)      39
          Decrease (increase) in prepaid expenses and other
            current assets....................................           9                 (6)           (6)       (8)      (5)
          Increase in other assets............................          --                 (4)           (3)       --       (1)
          Increase (decrease) in trade accounts payable.......          11                  6            (7)        7        1
          (Decrease) increase in accrued expenses and other
            liabilities.......................................         (62)                56            49       (73)      19
          (Decrease) increase in other liabilities............         (11)               (72)          (37)       10      (70)
                                                                     -----             ------         -----     -----     ----
               Net cash provided by operating activities......         113                 72           142       294      126
Cash flows from investing activities:
     Capital expenditures.....................................         (20)              (139)         (189)     (107)     (38)
                                                                     -----             ------         -----     -----     ----
               Net cash used in investing activities..........         (20)              (139)         (189)     (107)     (38)
Cash flows from financing activities:
     Net transactions with Millennium.........................         (88)                71            51      (184)     (84)
     Repayment of long term debt..............................          (5)                (4)           (4)       (3)      (4)
                                                                     -----             ------         -----     -----     ----
     Net cash (used in) provided by financing activities......         (93)                67            47      (187)     (88)
                                                                     -----             ------         -----     -----     ----
Net change in cash and cash equivalents.......................       $--               $--            $--       $--       $--
                                                                     -----             ------         -----     -----     ----
                                                                     -----             ------         -----     -----     ----
</TABLE>
 
                       See notes to financial statements.
 
                                      F-18
<PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                         NOTES TO FINANCIAL STATEMENTS
                                 (IN MILLIONS)
 
NOTE 1. BASIS OF PRESENTATION AND DESCRIPTION OF THE CONTRIBUTED BUSINESS
 
     On July 28, 1997, Millennium Chemicals Inc. ('Millennium') and Lyondell
Petrochemical Company ('Lyondell') announced an agreement to form a new joint
venture company which will be operated as a partnership (the 'Partnership'). The
Partnership, which will be owned 57% by Lyondell and 43% by Millennium, will own
and operate the existing olefins and polymers businesses to be contributed by
the two companies. The assets of the Partnership will consist of 13
manufacturing facilities on the US Gulf Coast and in the US Midwest, producing
ethylene, propylene, polyethylene (high-density, low-density and linear
low-density), polypropylene, ethyl alcohol, butadiene, aromatics, methyl
tertiary butyl ether ('MTBE') and other products for sale to customers located
throughout the US. The Partnership is expected to have $1.745 billion of debt,
including $745 assumed from Lyondell and $750 under a new credit facility, the
proceeds of which will be used to repay debt assumed from Millennium upon
completion of the transaction, and a note receivable from Lyondell of $345.
 
     Millennium will contribute to the Partnership substantially all of the net
assets and operations of its polyethylene and related products, performance
polymers and ethyl alcohol businesses (collectively, the 'Millennium Contributed
Business'). However, Millennium will retain the accounts receivable of the
contributed businesses arising prior to the formation of the Partnership.
 
     The accompanying financial statements, include the results of operations,
assets and liabilities of the businesses currently owned by Millennium that will
be contributed to the Partnership. These financial statements are presented on a
going concern basis and include only the historical net assets and results of
operations that are directly related to the Millennium Contributed Business.
Consequently, the financial position, results of operations and cash flows may
not be indicative of what would have been reported if the Millennium Contributed
Business had been a separate, stand-alone entity or had been operated as a part
of the Partnership during the periods presented.
 
     Millennium provided certain corporate, general and administrative services
to the Millennium Contributed Business, including legal, financial, tax, risk
management and employee benefits services. Charges for these services allocated
to the Millennium Contributed Business are believed to be reasonable and were $8
and $7 for the six months ended June 30, 1997 and 1996, respectively, and $18,
$13 and $8 for the years ended December 31, 1996, 1995 and 1994, respectively.
Such amounts are included in selling and administration expenses. In addition, a
subsidiary of Millennium has controlled, on a centralized basis, all cash
receipts and disbursements received or made by the Millennium Contributed
Business. The Millennium Contributed Business also sells ethylene to an
affiliated business unit of Millennium for the manufacture of vinyl acetate
monomer. Such sales, reflected at market prices, have been included in the
accompanying statements of income and aggregated $30, $27, $56, $63 and $47 for
the six months ended June 30, 1997 and 1996 and years ended December 31, 1996,
1995 and 1994, respectively. The net results of such transactions are included
in the balance sheets as invested capital. All significant intercompany accounts
and transactions within the Millennium Contributed Business have been
eliminated.
 
     The accompanying financial statements as of June 30, 1997 and 1996 and all
references made to amounts for the periods then ended are unaudited and have
been prepared in accordance with the rules and regulations of the Securities and
Exchange Commission. They include all adjustments which are considered necessary
for a fair statement of the results of operations and financial position of the
Millennium Contributed Business for the interim periods presented. Such
adjustments consisted only of normal recurring items.
 
NOTE 2. SIGNIFICANT ACCOUNTING POLICIES
 
     Revenue Recognition. Revenue from product sales is generally recognized
upon shipment of product to the customer.
 
                                      F-19
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
     Use of Estimates. The preparation of financial statements in conformity
with generally accepted accounting principles requires management to make
estimates and assumptions that affect the reported amounts of assets and
liabilities at the date of the financial statements and the reported amount of
revenues and expenses during the reporting period. Actual results could differ
from those estimates.
 
     Trade Receivables. Trade receivables consist of the following:
 
<TABLE>
<CAPTION>
                                                                                             DECEMBER 31,
                                                                               JUNE 30,      ------------
                                                                                 1997        1996    1995
                                                                              -----------    ----    ----
                                                                              (UNAUDITED)
 
<S>                                                                           <C>            <C>     <C>
Trade receivables..........................................................      $ 286       $270    $217
Allowance for doubtful accounts............................................         (1)        (1)     (1)
                                                                              -----------    ----    ----
                                                                                 $ 285       $269    $216
                                                                              -----------    ----    ----
                                                                              -----------    ----    ----
</TABLE>
 
     Accounts receivable are not being contributed to the Partnership at its
formation.
 
     Inventories. Inventories are stated at the lower of cost or market value.
Cost is determined for the various categories of inventory using first-in,
first-out ('FIFO'); last-in, first-out ('LIFO') basis or average cost method as
deemed appropriate. Inventories valued on a LIFO basis were approximately $7 and
$13 less than and $3 more than the amount of such inventories valued at current
cost at June 30, 1997, December 31, 1996 and 1995, respectively.
 
     Inventories consist of the following:
 
<TABLE>
<CAPTION>
                                                                                             DECEMBER 31,
                                                                               JUNE 30,      ------------
                                                                                 1997        1996    1995
                                                                              -----------    ----    ----
                                                                              (UNAUDITED)
 
<S>                                                                           <C>            <C>     <C>
Finished products..........................................................      $ 137       $154    $172
In-process products........................................................          2          2       2
Raw materials..............................................................         61        105      74
Other inventories..........................................................         39         33      31
                                                                              -----------    ----    ----
                                                                                 $ 239       $294    $279
                                                                              -----------    ----    ----
                                                                              -----------    ----    ----
</TABLE>
 
     Property, Plant and Equipment. Property, plant and equipment is stated on
the basis of cost. Depreciation is computed using the straight-line method over
the estimated useful lives of the assets, generally 20 to 40 years for buildings
and 10 to 25 years for machinery and equipment.
 
     Property, plant and equipment consists of the following:
 
<TABLE>
<CAPTION>
                                                                                           DECEMBER 31,
                                                                           JUNE 30,      ----------------
                                                                             1997         1996      1995
                                                                          -----------    ------    ------
                                                                          (UNAUDITED)
 
<S>                                                                       <C>            <C>       <C>
Land and buildings.....................................................     $   120      $  125    $  125
Machinery and equipment................................................       1,540       1,516     1,314
Leasehold improvements.................................................           4           4         4
                                                                          -----------    ------    ------
                                                                              1,664       1,645     1,443
Allowance for depreciation and amortization............................         359         310       206
                                                                          -----------    ------    ------
                                                                            $ 1,305      $1,335    $1,237
                                                                          -----------    ------    ------
                                                                          -----------    ------    ------
</TABLE>
 
     Turnaround Maintenance. Costs in excess of $5 relating to future major
maintenance projects are estimated and expensed ratably from the date a
turnaround is completed until the next planned turnaround, generally 4 to 6
years.
 
     Goodwill. The net assets of the Millennium Contributed Business include
goodwill of $1,155 at June 30, 1997, which is being amortized using the straight
line method over forty years. Such goodwill
 
                                      F-20
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
arose from Millennium's 1993 acquisition of Quantum Chemical Corporation of
which the Millennium Contributed Business was a part. The value of the purchase
consideration was allocated to the acquired assets and liabilities based on
their fair values, resulting in $1,272 of goodwill being allocated to the
Millennium Contributed Business. Management periodically evaluates goodwill for
impairment based on the anticipated future cash flows attributable to the
operation. Such expected cash flows, on a undiscounted basis, are compared to
the carrying value of the tangible and intangible assets, and if impairment is
indicated, the carrying value of goodwill is adjusted. Management believes that
no impairment exists at June 30, 1997. Accumulated amortization aggregated $117,
$101, and $70 at June 30, 1997, December 31, 1996 and 1995, respectively.
Amortization of goodwill amounted to $16 each for the six months ended June 30,
1997 and 1996, respectively and $31 each for the years ended December 31, 1996,
1995 and 1994, respectively.
 
     Accrued Expenses and Other Liabilities. Accrued expenses and other
liabilities consist of the following:
 
<TABLE>
<CAPTION>
                                                                                         DECEMBER 31,
                                                                   JUNE 30,      ----------------------------
                                                                     1997            1996            1995
                                                                 ------------    ------------    ------------
                                                                 (UNAUDITED)
 
<S>                                                              <C>             <C>             <C>
Major maintenance.............................................       $ 28            $ 56            $ 47
Feedstock accruals............................................         23              65              20
All other.....................................................         55              47              52
                                                                   ------          ------          ------
     Total....................................................       $106            $168            $119
                                                                   ------          ------          ------
                                                                   ------          ------          ------
</TABLE>
 
     Accounts payable and certain accrued expenses are not being contributed to
the Partnership at its formation.
 
     Environmental Liabilities and Expenditures. Accruals for environmental
matters are recorded in operating expenses when it is probable that a liability
has been incurred and the amount of the liability can be reasonably estimated.
Accrued liabilities are exclusive of claims against third parties (except where
payment has been received or the amount of liability or contribution by such
other parties, including insurance companies, has been agreed) and are not
discounted. In general, costs related to environmental remediation are charged
to expense. Environmental costs are capitalized if the costs increase the value
of the property and/or mitigate or prevent contamination from future operations.
 
     Federal Income Taxes. Earnings of the Millennium Contributed Business have
been included in a consolidated income tax returns filed by its ultimate U.S.
parent, Millennium America Holdings Inc. ('MAHI'), a subsidiary of Millennium.
Pursuant to an informal tax allocation agreement, income taxes have been
allocated to the Millennium Contributed Business based on applicable statutory
tax rates applied to the taxable earnings generated by such business. Effective
income tax rates for the periods as of and at June 30, 1997 and 1996 and
December 31, 1996, 1995 and 1994 were 42.7%, 55.3%, 45.2%, 41.4% and 47.7%,
respectively. Differences between the effective income tax rates and the
statutory federal income tax rates arise primarily from goodwill amortization
and state income taxes. Liabilities for current and/or deferred income taxes
have been and remain the responsibility of MAHI, and accordingly, have been
included in the balance sheet as invested capital.
 
     As part of the transactions to consummate the Partnership, Millennium will
enter into tax sharing and indemnification agreements with the Partnership in
which Millennium will generally agree to indemnify the Partnership for income
tax liabilities attributable to periods when the operations of the Millennium
Contributed Business were included in the consolidated tax returns of MAHI.
 
     Research and Development. The cost of research and development efforts is
expensed as incurred. Such costs aggregated $16, $16, $33, $32 and $31 for the
six months ended June 30, 1997 and 1996 and the years ended December 31, 1996,
1995 and 1994, respectively.
 
                                      F-21
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
     Fair Value of Financial Instruments. The fair values of all short-term
financial instruments are estimated to approximate their carrying value because
of their short maturity. The carrying value of the note payable and other
indebtedness to Millennium approximates fair value since such debt will be
repaid or redeemed as a result of the formation of the Partnership.
 
     Earnings Per Share. Historical earnings per share are not presented because
there is no separate identifiable pool of capital for the periods prior to
incorporation upon which a per share calculation could be based.
 
NOTE 3. LONG-TERM DEBT AND INDEBTEDNESS TO MILLENNIUM
 
     The debt included in the balance sheets reflects the obligations directly
related to the Millennium Contributed Business including allocated debt from
Millennium. Other indebtedness to Millennium, while included herein as debt
allocated to the Contributed Business will not be assumed by the Partnership
upon Closing. Upon consummation of the Partnership the note payable to
Millennium will be repaid using $750 proceeds under a new bank credit facility
arranged by the Partnership.
 
<TABLE>
<CAPTION>
                                                                                           DECEMBER 31,
                                                                           JUNE 30,      ----------------
                                                                             1997         1996      1995
                                                                          -----------    ------    ------
                                                                          (UNAUDITED)
 
<S>                                                                       <C>            <C>       <C>
Note payable to Millennium bearing interest at 8% due 2006.............     $   750      $  750    $  750
Other indebtedness to Millennium.......................................         250         250       250
Industrial revenue bonds bearing interest at 5.5% due 1998.............           4           9        13
Less current maturities................................................          (2)         (4)       (4)
                                                                          -----------    ------    ------
                                                                            $ 1,002      $1,005    $1,009
                                                                          -----------    ------    ------
                                                                          -----------    ------    ------
</TABLE>
 
     Interest paid for the six months ended June 30, 1997 and 1996 and the years
ended December 31, 1996, 1995 and 1994 was $40, $40, $80, $80, and $80,
respectively.
 
NOTE 4. PENSION AND OTHER POSTRETIREMENT BENEFITS
 
     All full-time employees of the Millennium Contributed Business are covered
by defined benefit pension plans sponsored by Millennium. Retirement benefits
are based on years of service and average compensation as defined under the
respective plans' provisions. The funding policy is to contribute amounts to the
plans sufficient to meet the minimum funding requirements set forth in the
Employee Retirement Income Security Act of 1974. The Millennium Contributed
Business accrues pension costs based on actuarial valuations and funds the plan
through contributions to Millennium who then contributes the funds to a master
trust sponsored by Millennium. Such contributions are reflected in invested
capital. Pension income related to participation in these plans was $2, $2, $5,
$4 and $6 for the six months ended June 30, 1997 and 1996 and the years ended
December 31, 1996, 1995 and 1994, respectively. One such plan covers benefits
for union-represented employees of the Millennium Contributed Business. Such
plan will be assumed by the Partnership upon its consummation. The following
table sets forth the funded status of such plan.
 
                                      F-22
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
<TABLE>
<CAPTION>
                                                                                       PLAN WHOSE ASSETS
                                                                                      EXCEEDED ACCUMULATED
                                                                                            BENEFITS
                                                                                      --------------------
                                                                                          DECEMBER 31,
                                                                                      --------------------
                                                                                        1996        1995
                                                                                      --------    --------
 
<S>                                                                                   <C>         <C>
Actuarial present value of benefit obligations:
     Vested benefit obligation.....................................................     $(18)       $(15)
     Nonvested benefit obligation..................................................       (1)         (1)
                                                                                      --------    --------
     Accumulated benefit obligation................................................      (19)        (16)
                                                                                      --------    --------
Projected benefit obligation.......................................................      (20)        (17)
Plan assets at fair value..........................................................       37          35
                                                                                      --------    --------
Projected benefit obligation less than plan assets.................................       17          18
Add:
     Unrecognized net loss.........................................................        4           2
                                                                                      --------    --------
Prepaid pension costs (included in other assets)...................................     $ 21        $ 20
                                                                                      --------    --------
                                                                                      --------    --------
</TABLE>
 
     The plans' assets are primarily included in a master trust sponsored by
Millennium, which principally invests in listed stocks and bonds, including
common stock of Millennium which, at market value, comprised less than 1% of the
master trust's assets at June 30, 1997.
 
     Millennium also provides unfunded health care and life insurance benefits
to certain groups of retirees. Expenses related to the employees of the
Millennium Contributed Business were $1, $1, $2, $2, and $2 for the six months
ended June 30, 1997 and 1996 and the years ended December 31, 1996, 1995 and
1994 respectively. The actuarially determined liability associated with the
currently active employees of the Millennium Contributed Business based upon
current plan provisions at December 31, 1996 was $19.
 
NOTE 5. COMMITMENTS AND CONTINGENCIES
 
     The Millennium Contributed Business is subject, among other things, to
several proceedings under the Federal Comprehensive Environmental Response
Compensation and Liability Act and other federal and state statutes. These
proceedings are in various stages ranging from initial investigation to active
settlement negotiations to implementation of clean-up or remediation of sites.
Additionally, Millennium and/or its subsidiaries are defendants or plaintiffs in
lawsuits that have arisen in the normal course of business including those
relating to commercial transactions and product liability with respect to the
Millennium Contributed Business.
 
     As part of the transactions to consummate the Partnership, Millennium will
agree to indemnify the Partnership for any present or future liabilities arising
within a seven year period after the consummation of the Partnership which are
attributable to the Millennium Contributed Business's operations prior to the
Partnership's formation in excess of $7; accordingly, the Millennium Contributed
Business has accrued $7 at June 30, 1997 for its share of liabilities for
matters known at the present time.
 
     The Millennium Contributed Business has various contractual obligations to
purchase raw materials used in its production of polyethylene. Commitments to
purchase ethylene used in the production of polyethylene are based on market
prices and expire from 1997 through 2001.
 
NOTE 6. LEASES
 
     Rental expense for operating leases was $22, $22, $45, $43 and $40 for the
six months ended June 30, 1997 and 1996 and the years ended December 31, 1996,
1995 and 1994.
 
                                      F-23
 <PAGE>
<PAGE>
                        MILLENNIUM CONTRIBUTED BUSINESS
                  NOTES TO FINANCIAL STATEMENTS -- (CONTINUED)
                                 (IN MILLIONS)
 
MINIMUM RENTALS
 
     Future minimum rental commitments under noncancellable operating leases
with terms in excess of one year as of December 31, 1996 are as follows:
 
<TABLE>
<S>                                    <C>
1997................................   $ 42
1998................................     36
1999................................     32
2000................................     18
2001................................      9
Thereafter..........................     22
                                       ----
                                       $159
                                       ----
                                       ----
</TABLE>
 
                                      F-24

<PAGE>
<PAGE>
                                                                         ANNEX A
 
                                [LETTERHEAD OF]
                              SALOMON BROTHERS INC
 
July 25, 1997

Board of Directors
Lyondell Petrochemical Company
1221 McKinney St., Suite 1600
Houston, TX 77010


Members of the Board:
 
     You have requested our opinion as to the fairness, from a financial point
of view, to Lyondell Petrochemical Company ('Lyondell' or the 'Company') of the
allocation between the Company and Millennium Chemicals Inc. ('Millennium') of
the ownership of the partnership (the 'Partnership') to be formed by the Company
and Millennium pursuant to the Master Transaction Agreement, dated July 25, 1997
(the 'Transaction Agreement'), between Lyondell and Millennium.
 
     Under the Transaction Agreement, in exchange for a 57% equity ownership
interest in the Partnership: (i) Lyondell will contribute to the Partnership all
the assets, rights and properties used or held for use in the operation and
conduct of its petrochemicals business (the 'Lyondell Contributed Business') as
described in the Petrochemicals Segment of Lyondell's 1996 Annual Report on Form
10-K (other than its interest in Lyondell Methanol Company, certain technology
rights, mainframe leases, mainframe owned assets, equipment and other personal
property associated with its corporate staff and certain other software); (ii)
the Partnership will assume and agree to pay, perform and discharge (A) all
obligations arising after the closing date under the contracts and leases
assigned to the Partnership by Lyondell, (B) all obligations under purchase
orders accepted by Lyondell in the ordinary course of the Lyondell Contributed
Business, (C) certain specified indebtedness of Lyondell with an aggregate
principal amount of approximately $745 million, and (D) certain other specified
obligations and liabilities arising out of, in connection with or related to the
Lyondell Contributed Business; and (iii) Lyondell will contribute to the
Partnership a promissory note in the principal amount of $345 million.
 
     Under the Transaction Agreement, in exchange for a 43% equity ownership
interest in the Partnership: (i) Millennium will contribute to the Partnership
certain assets, rights and properties used or held for use in the operation and
conduct of its polyethylene and related products, ethyl alcohol and ethyl ether
and performance polymers business (the 'Millennium Contributed Business') as
described in the Petrochemicals Section of Millennium's 1996 Annual Report on
Form 10-K and (ii) the Partnership will assume and agree to pay, perform and
discharge (A) all obligations arising after the closing date under the contracts
and leases assigned to the Partnership by Millennium, (B) all obligations under
purchase orders accepted by Millennium in the ordinary course of the Millennium
Contributed Business, (C) certain specified indebtedness of Millennium with an
aggregate principal amount of approximately $750 million, and (D) certain other
specified obligations and liabilities arising out of, in connection with or
related to the Millennium Contributed Business. The transactions contemplated by
the Transaction Agreement are referred to in this opinion as the 'Transactions.'
 
     In connection with rendering our opinion, we have reviewed certain publicly
available information concerning the Company, Millennium, the Lyondell
Contributed Business and the Millennium Contributed Business and certain other
financial information concerning the Company, Millennium, the Lyondell
Contributed Business and the Millennium Contributed Business that were provided
to us by the Company and Millennium. We have reviewed financial forecasts for
the Lyondell Contributed Business that were provided to us by the Company, as
well as financial forecasts for the Millennium Contributed Business that were
provided by each of the Company and Millennium. We have discussed the past and
current business operations, financial condition and prospects of the Lyondell
Contributed Business and the Millennium Contributed Business with certain
officers and employees of the Company and Millennium, respectively. We have also
considered such other information, financial studies, analyses, investigations
and financial, economic and market criteria that we deemed relevant.
 
                                      A-1

<PAGE>
<PAGE>
     We draw your attention to an agreement between Millennium and us that
prohibits us from disclosing to the Company, its board of directors or
management certain information, including financial forecasts, received by us
from Millennium and relating to the Millennium Contributed Business. The
consequences of this agreement, which was entered into at the request of the
Company and with the Company's approval, include (i) our inability to disclose
to or review with the Company the financial forecasts for the Millennium
Contributed Business prepared by Millennium and (ii) our inability to assist the
Company in its preparation and verification of the Company's financial forecasts
for the Millennium Contributed Business.
 
     In our review and analysis and in arriving at our opinion, we have assumed
and relied upon the accuracy and completeness of the information reviewed by us
for the purpose of this opinion and we have not assumed any responsibility for
independent verification of such information. With respect to the financial
forecasts for the Lyondell Contributed Business, we have assumed that they have
been reasonably prepared on bases reflecting the best currently available
estimates and judgements of the management of the Company, and we express no
opinion with respect to such forecasts or the assumptions on which they are
based. With respect to the financial forecasts for the Millennium Contributed
Business prepared by Millennium, we have assumed that they have been reasonably
prepared on bases reflecting the best currently available estimates and
judgements of the management of Millennium, and we express no opinion with
respect to such forecasts or the assumptions on which they are based. In light
of the agreement between Millennium and us described above, we express
absolutely no view or opinion, and make no assumptions, with respect to the
financial forecasts for the Millennium Contributed Business prepared by the
Company. We have not assumed any responsibility for any independent evaluation
or appraisal of any of the assets (including properties and facilities) or
liabilities of the Company or Millennium. We were not asked to, and did not,
solicit proposals to acquire the Company or the Lyondell Contributed Business.
 
     Our opinion is necessarily based upon conditions as they exist and can be
evaluated on the date hereof. Our opinion does not address the Company's
underlying business decision to implement the Transactions, nor does it address
(other than as provided in the immediately following sentence) the terms of the
partnership agreement governing the Partnership. Our opinion is directed only to
the fairness, from a financial point of view, of the allocation of ownership of
the Partnership to the Company and does not constitute a recommendation
concerning how holders of capital stock of the Company should vote with respect
to the Transaction Agreement or the Transactions.
 
     We have acted as financial advisor to the Company in connection with the
Transactions and will receive a fee for our services, which is contingent upon
consummation of the Transactions. In the ordinary course of business, we may
actively trade the securities of the Company and Millennium for our own account
and for the accounts of customers and, accordingly, may at any time hold a long
or short position in such securities. In addition, we have previously rendered
certain investment banking and financial advisory services to the Company and
Millennium for which we have received customary compensation.
 
     Based upon and subject to the foregoing, it is our opinion that, as of the
date hereof, the allocation of 57% of the equity ownership in the Partnership to
the Company and 43% of the equity ownership in the Partnership to Millennium is
fair to the Company from a financial point of view.
 
                                          Very truly yours,


                                          SALOMON BROTHERS INC
 
                                      A-2

<PAGE>
<PAGE>
                                                                         ANNEX B
 
                                [LETTERHEAD OF]
                          J.P. MORGAN SECURITIES INC.
 
                                                                   July 23, 1997
 
The Board of Directors
Millennium Chemicals Inc.
99 Wood Avenue South
Iselin, NJ 08830
 
Attention: William M. Landuyt
         Chairman & Chief Executive Officer
 
Ladies and Gentlemen:
 
     You have requested our opinion as to the fairness, from a financial point
of view, to Millennium Chemicals Inc. (the 'Company') of the consideration
proposed to be received by the Company in connection with the proposed
contribution of certain of the Company's assets to a joint venture (the 'Joint
Venture') with Lyondell Petrochemical Company (the 'Partner'). Pursuant to a
Master Transaction Agreement to be executed on July 25, 1997 (the 'Agreement'),
between the Company and the Partner, the Company and the Partner will contribute
certain assets to the Joint Venture, and the Company will receive consideration
equal to a forty-three percent ownership stake in the Joint Venture along with
cash consideration of $1 billion.
 
     In arriving at our opinion, we have reviewed (i) a draft of the Agreement
(including the Guarantee Agreement, Limited Partnership Agreement, and Asset
Contribution Agreeemnt referred to therein); (ii) certain information concerning
the contributed assets of the Company and the Partner and certain publicly
available information concerning certain other companies engaged in businesses
comparable to those of the Joint Venture; (iii) publicly available terms of
certain transactions involving companies or assets comparable to the assets
being contributed to the Joint Venture and the consideration received in
connection with such transactions; (iv) the audited financial statements of the
Company and the Partner for the fiscal year ended December 31, 1996, and the
unaudited financial statements of the Company and the Partner for the period
ended March 31, 1997; (v) certain agreements with respect to outstanding
indebtedness or obligations of the Joint Venture; (vi) certain internal
financial analyses and forecasts concerning the Joint Venture prepared by the
management of the Company and Partner; and (vii) the terms of other business
combinations that we deemed relevant.
 
     In addition, we have held discussions with certain members of the
management of the Company and the Partner with respect to certain aspects of the
Joint Venture, and the past and current business operations of the Company, the
Partner and the Joint Venture, the financial condition and future prospects and
operations of the Company, the Partner and the Joint Venture, the effects of the
Joint Venture on the financial condition and future prospects of the Company and
certain other matters we believed necessary or appropriate to our inquiry. We
have visited certain representative facilities of the Joint Venture, and
reviewed such other financial studies and analyses and considered such other
information as we deemed appropriate for the purposes of this opinion.
 
     In giving our opinion, we have relied upon and assumed, without independent
verification, the accuracy and completeness of all information that was publicly
available or was furnished to us by the Company and the Partner, or otherwise
reviewed by us, and we have not assumed any responsibility or liability
therefor. We have not conducted any valuation or appraisal of any selected
assets or liabilities, nor have any appraisals been provided to us. In relying
on financial analyses and forecasts provided to us, we have assumed that they
have been reasonably prepared based on assumptions reflecting the best currently
available estimates and judgments by management as to the expected future
results of operations and financial condition of the Joint Venture to which such
analyses or forecasts relate. We have also assumed that the creation of the
Joint Venture will have the tax consequences described to us in discussions
with, and materials furnished to us by, representatives of the Company, and that
the other
 
                                      B-1
<PAGE>
<PAGE>
transactions contemplated by the Agreement will be consummated as described in
such Agreement. We have relied as to all legal matters relevant to rendering our
opinion upon the advice of counsel.
 
     Our opinion is necessarily based on economic, market and other conditions
as in effect on, and the information made available to us as of, the date
hereof. It should be understood that subsequent developments may affect this
opinion and that we do not have any obligation to update, revise, or reaffirm
this opinion.
 
     In addition, we were not requested to and did not provide advice concerning
the structure, or any other aspects of the Transaction, or to provide services
other than the delivery of this opinion.
 
     We will receive a fee from the Company for the delivery of this opinion.
Please be advised that we have no other financial advisory or other
relationships with the Partner. We have acted as a lender and underwriter of
securities for the Company. In the ordinary course of their businesses, our
affiliates may actively trade the debt and equity securities of the Company or
the Partner for their own account or for the accounts of customers and,
accordingly, they may at any time hold long or short positions in such
securities.
 
     On the basis of and subject to the foregoing, it is our opinion as of the
date hereof that the consideration to be received by the Company in the proposed
Joint Venture is fair, from a financial point of view, to the Company.
 
     This letter is provided to the Board of Directors of the Company in
connection with and for the purposes of its evaluation of the Joint Venture.
This opinion does not constitute a recommendation to any stockholder of the
Company as to how such stockholder should vote with respect to the Joint
Venture. This opinion may not be disclosed, referred to, or communicated (in
whole or in part) to any third party for any purpose whatsoever except with our
prior written consent in each instance. This opinion may be reproduced in full
in any proxy or information statement mailed to stockholders of the Company but
may not otherwise be disclosed publicly in any manner without our prior written
approval and must be treated as confidential.
 
                                          Very truly yours,

                                          J.P. MORGAN SECURITIES INC.


                                          By: /s/ D. LESLIE A. MORRISON
                                             ...................................
                                            Name: D. Leslie A. Morrison
                                            Title: Managing Director
 
                                      B-2

<PAGE>
<PAGE>
                Directions to meeting of Lyondell stockholders:
 
                                   [TO COME]
 
               Directions to meeting of Millennium stockholders:

                               [INSTRUCTION MAP]

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<PAGE>

                                   APPENDIX 1
                     LYONDELL PETROCHEMICAL COMPANY PROXY CARD

                                     [LOGO]
                               ONE HOUSTON CENTER
                           1221 MCKINNEY, SUITE 1600
                              HOUSTON, TEXAS 77010
 
          THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS
 
     The undersigned hereby makes, constitutes and appoints Joseph M. Putz,
Debra L. Starnes and Russell S. Young and each of them, lawful attorney and
proxies of the undersigned, with full power of substitution, for and in the
name, place and stead of the undersigned to attend the Special Meeting of
Stockholders of Lyondell Petrochemical Company (herein the 'Company') in the
                        ,                            , Houston, Texas, on
       ,            , 1997 at 10:00 a.m., local time, and at any adjournment(s)
thereof, with all powers the undersigned would be entitled to vote if
personally present.
 
     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 ITEM 1.
 
     This card also constitutes your voting instructions for shares held in the
Lyondell Petrochemical Company 401(k) and Savings Plan, the LYONDELL-CITGO
Refining Company Ltd. 401(k) and Savings Plan for Non-Represented Employees and
the LYONDELL-CITGO Refining Company Ltd. 401(k) and Savings Plan for Represented
Employees, and the undersigned hereby authorizes State Street Bank, as Trustee
of such plans to vote the shares held in the undersigned's accounts.
 
LYONDELL PETROCHEMICAL COMPANY
P.O.BOX 11244
NEW YORK, N.Y. 10203-0244
 
                                                (Continued, and to be signed and
                                                        dated, on reverse side.)
 
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<PAGE>


                                     [LOGO]
                               ONE HOUSTON CENTER
                           1221 MCKINNEY, SUITE 1600
                              HOUSTON, TEXAS 77010
 
        , 1997
 
Dear Stockholder:
 
     You are cordially invited to join us at the Special Meeting of Stockholders
on                        ,            , 1997, beginning at 10:00 a.m. in the
                         , in Houston, Texas.
 
     It is important that your shares be voted whether or not you plan to be
present at the meeting. Please complete, sign, date and return the enclosed form
of proxy promptly. If you do plan to attend, we would appreciate your checking
the appropriate box on the enclosed proxy card.
 
     This booklet includes the Notice of the Meeting and the Proxy Statement,
which contains information about the formal business to be acted upon by the
stockholders. The official results of the voting at the meeting will be sent to
all stockholders as part of a subsequent stockholder report.
 

Sincerely yours,



DAN F. SMITH
President and Chief Executive Officer
 
                         PLEASE DETACH PROXY CARD HERE
 

 
1. Approval of the proposed joint venture between the Company and Millennium
   Chemicals Inc.
 
FOR [ ]   AGAINST [ ]  ABSTAIN   [ ]
 
2. In their discretion, the proxies are authorized to vote upon such other
business as may properly come before the meeting.
 


 
I/WE WILL ATTEND MEETING. [  ]                    ADDRESS CHANGE MARK HERE  [  ]

PLEASE SIGN EXACTLY AS NAME APPEARS. WHEN SHARES ARE HELD BY JOINT TENANTS, BOTH
SHOULD SIGN. WHEN SIGNING AS ATTORNEY, EXECUTOR, ADMINISTRATOR, TRUSTEE OR
GUARDIAN, PLEASE GIVE FULL TITLE AS SUCH.
 
DATED:---------------------------------,1997

- --------------------------------------------
                 Signature

- --------------------------------------------
         Signature if held jointly
Votes MUST be indicated (x) in Black or Blue ink.    [ X ]

PLEASE SIGN, DATE AND RETURN THE PROXY PROMPTLY USING THE ENCLOSED ENVELOPE.


<PAGE>

<PAGE>

                                       APPENDIX 2
                           MILLENNIUM CHEMICALS INC. PROXY CARD
                                         PROXY
                               MILLENNIUM CHEMICALS INC.
                 PROXY SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS OF
                   THE COMPANY FOR THE SPECIAL MEETING OF STOCKHOLDERS
 
                                            , 1997

    The undersigned hereby constitutes and appoints William M. Landuyt,
    John E. Lushefski and George H. Hempstead, III, and each of them, his true
    and lawful agents and proxies with full power of substitution in each,
    to represent the undersigned at the Special Meeting of Stockholders of
    MILLENNIUM  CHEMICALS  INC.  (the  "Company")  to  be  held  at             
    and at any adjournments thereof, on all matters coming before said meeting.
 

    1. Approval of the proposed joint venture between the Company and Lyondell
       Petrochemical Company (the "Joint Venture"), including the proposed
       contribution to the Joint Venture of substantially all of the assets
       comprising the Company's polyethylene and related products, performance
       polymers and ethyl alcohol businesses (other than the related accounts
       receivable) (the "Asset Contribution").

    YOU ARE ENCOURAGED TO SPECIFY YOUR CHOICE BY MARKING THE APPROPRIATE
    BOX, SEE REVERSE SIDE, BUT YOU NEED NOT MARK ANY BOX IF YOU WISH TO
    VOTE IN ACCORDANCE WITH THE BOARD OF DIRECTORS' RECOMMENDATION. THE
    PROXIES CANNOT VOTE YOUR SHARES UNLESS YOU SIGN AND RETURN THIS CARD.
 
<PAGE>

<PAGE>


    X Please mark your votes as in this example.                    0625

    THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED IN THE MANNER DIRECTED
    HEREIN. IF NO DIRECTION IS MADE, THIS PROXY WILL BE VOTED "FOR" PROPOSAL 1.
     -------------------------------------------------------------------
        THE BOARD OF DIRECTORS RECOMMENDS A VOTE FOR PROPOSAL 1.
     -------------------------------------------------------------------
     1. Approval of the Joint Venture, including the Asset Contribution.
                                                    FOR   AGAINST  ABSTAIN


SIGNATURE(S)------------------------------------    DATE -----------------

NOTE: PLEASE SIGN EXACTLY AS YOUR NAME APPEARS HEREON. JOINT OWNERS SHOULD EACH
SIGN. WHEN SIGNING AS ATTORNEY, EXECUTOR, ADMINISTRATOR, TRUSTEE OR GUARDIAN,
PLEASE GIVE FULL TITLE AS SUCH.
The signer hereby revokes all proxies heretofore given by the signer to vote at
said meeting or any adjournments thereof.


<PAGE>

<PAGE>

                              STATEMENT OF DIFFERENCES
                              ------------------------

The registered trademark symbol shall be expressed as 'r'




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