Document:

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                                                                     EXHIBIT 4.3
                                                                  EXECUTION COPY

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                          REGISTRATION RIGHTS AGREEMENT

                                     BETWEEN

                     OCCIDENTAL CHEMICAL HOLDING CORPORATION

                                       AND

                            LYONDELL CHEMICAL COMPANY

                                 August 22, 2002

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                                TABLE OF CONTENTS

<TABLE>
<S>                                                                        <C>
SECTION 1 DEMAND REGISTRATION ..........................................    1
     1.1      Registration Rights ......................................    1
     1.2      Underwriting Requirements ................................    2
     1.3      Limitations ..............................................    2

SECTION 2 COMPANY "PIGGYBACK" REGISTRATION .............................    4
     2.1      Registration Rights ......................................    4
     2.2      Underwriting Requirements ................................    4
     2.3      Rightsholder Right to Withdraw ...........................    4
     2.4      Company Right to Withdraw ................................    4

SECTION 3 ADDITIONAL COMPANY OBLIGATIONS ...............................    5

SECTION 4 ADDITIONAL OBLIGATIONS OF RIGHTSHOLDERS ......................    8
     4.1      General ..................................................    8
     4.2      Participation in Underwritten Registrations ..............    8
     4.3      Discontinuation of Sales Upon Certain Events .............    8
     4.4      Holdback .................................................    9

SECTION 5 EXPENSES OF REGISTRATION .....................................    9

SECTION 6 INDEMNIFICATION ..............................................    9
     6.1      Company's Indemnification ................................    9
     6.2      Rightsholders' Indemnification ...........................   10
     6.3      Additional Procedures ....................................   10
     6.4      Unavailability ...........................................   11
     6.5      Conflict With Underwriting Agreement .....................   11
     6.6      Survival .................................................   11

SECTION 7 RULE 144 .....................................................   11

SECTION 8 ASSIGNMENT OF REGISTRATION RIGHTS ............................   12

SECTION 9 TERMINATION OF REGISTRATION RIGHTS ...........................   12

SECTION 10 LIMITATIONS ON SUBSEQUENT REGISTRATION RIGHTS ...............   12

SECTION 11 MISCELLANEOUS ...............................................   12
     11.1     Successors and Assigns ...................................   12
     11.2     Benefits of Agreement Restricted to Parties ..............   13
     11.3     Notices ..................................................   13
     11.4     Severability .............................................   14
     11.5     Entire Agreement .........................................   14
     11.6     Construction .............................................   14
     11.7     Counterparts .............................................   14
</TABLE>

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<TABLE>
<S>                                                                        <C>
     11.8     Governing Law ............................................   14
     11.9     Amendment ................................................   14
     11.10    Recapitalizations, Exchanges, etc. .......................   15
     11.11    Jurisdiction; Consent to Service of Process; Waiver ......   15
     11.12    Waiver of Jury Trial .....................................   15
</TABLE>

APPENDIX

Appendix A         Definitions

                                      -ii-

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                          REGISTRATION RIGHTS AGREEMENT

          This REGISTRATION RIGHTS AGREEMENT (this "Agreement"), dated as of
August 22, 2002, is entered into by Occidental Chemical Holding Corporation, a
California corporation ("OCHC"), and Lyondell Chemical Company, a Delaware
corporation (the "Company").

          The definitions of capitalized terms used in this Agreement are set
forth in Appendix A.

          WHEREAS, the Company and OCHC entered into a Securities Purchase
Agreement dated July 8, 2002 (the "Securities Purchase Agreement"), governing
the sale by the Company of shares of Series B Common Stock on the Closing Date
(as defined in the Securities Purchase Agreement), certain additional shares of
Series B Common Stock that may be issuable in the future upon and subject to the
terms and conditions of the Securities Purchase Agreement, and warrants for the
purchase of 5,000,000 shares of Original Common Stock (the "Warrant"), as
adjusted pursuant to the terms thereof, to OCHC;

          WHEREAS, the terms of the Securities Purchase Agreement provide for
the execution and delivery of this Agreement; and

          WHEREAS, pursuant to the terms of the Securities Purchase Agreement,
the Company, Occidental Petroleum Corporation, a Delaware corporation
("Occidental"), and OCHC are entering into a Stockholders Agreement dated as of
the date of this Agreement (the "Stockholder Agreement");

          NOW, THEREFORE, in consideration of the premises and the mutual
covenants of the Parties set forth herein, it is hereby agreed as follows:

                                    SECTION 1
                               DEMAND REGISTRATION

     1.1 Registration Rights. Subject to Sections 1.2 and 1.3, if one or more
Rightsholders provide the Company at any time a written request that the Company
file a registration statement under the Securities Act covering the registration
of Registrable Securities owned by such Rightsholder (that request being
referred to as an "Initial Demand Request" and such registration being referred
to as a "Demand Registration"), the Company shall:

          (a) within 10 days after receiving the Initial Demand Request, notify
     all other Rightsholders of such request (the "Company Notice");

          (b) from the date the Company delivers the Company Notice, give all
     other Rightsholders 15 days to notify the Company of the number of
     Registrable Securities such other Rightsholders desire the Company to
     include in the registration statement relating to such Demand Registration;
     and

<PAGE>

          (c) within 45 days after receiving the Initial Demand Request, file a
     registration statement under the Securities Act covering all Registrable
     Securities that the Rightsholders requested to be registered and, after
     such filing, use commercially reasonable efforts to cause such registration
     statement to be declared effective.

The Initial Demand Request shall specify the number of shares of Registrable
Securities proposed to be sold and the manner of distribution.

          1.2 Underwriting Requirements. If an Initial Demand Request provides
for the sale of Registrable Securities in an underwritten offering and an OCHC
Party is participating in the related registration, then OCHC shall have the
right to select the lead managing underwriter for such underwriting in its sole
discretion and to select the other underwriters for such underwriting, subject
to the consent of the Company which shall not be unreasonably withheld. In such
event, the participating OCHC Party shall specify the proposed underwriters in
the Initial Demand Request or the notice delivered pursuant to Section 1.1(b).
If the Initial Demand Request or the notice delivered pursuant to Section 1.1(b)
provides for the sale of Registrable Securities in an underwritten offering and
no OCHC Party is participating, the Company shall have the right to select all
underwriters. In the case of an underwritten offering, any Rightsholder or other
holder of Securities that has the right to include Securities in that Demand
Registration and elects to do so shall participate, and include those
Securities, in the underwriting as provided in this Agreement. Notwithstanding
any other provision of Section 1, if the lead managing underwriter advises the
Company in writing that the total amount of Securities proposed to be included
in the offering, including by the Company and the Rightsholders, exceeds the
amount of Securities that is compatible with the offering's success, then the
Company shall:

          (a) so advise all Rightsholders and other holders of Securities that
     would otherwise have Securities registered under such registration
     statement;

          (b) to the extent necessary, entirely exclude from such registration
     statement all Securities (including Securities the Company owns or proposes
     to issue) other than Rightsholders' Registrable Securities and Securities
     subject to pari passu registration rights; and

          (c) to the extent necessary after effecting such exclusion, allocate
     the number of Securities the registration will cover on a pro-rata basis
     among the Rightsholders and all other holders of Securities subject to pari
     passu registration rights according to the total number of Securities each
     of them owns subject to registration rights to reduce the total amount of
     Securities to be included in such offering to the amount recommended by the
     lead managing underwriter. To facilitate allocating shares in accordance
     with this Section 1.2(c), the Company may round the number of shares
     allocated to any Rightsholder to the nearest 100 shares.

     1.3  Limitations.

          (a) The Company will not be obligated to initiate any Demand
     Registration at any time if (i) doing so would breach any provision of any
     applicable Rightsholders'

                                      -2-

<PAGE>

     agreement entered into pursuant to Section 4.4 or (ii) the Company
     determines in good faith that the registration and distribution of
     Registrable Securities in a Demand Registration would materially impede,
     delay or interfere with any firm-commitment underwritten offering of
     Securities by the Company (including an offering involving sales of
     Securities to initial purchasers who intend to resell the Securities under
     Rule 144A of the Securities Act, Regulation S or to accredited investors
     (as defined in the Securities Act)) on which the Company has commenced work
     prior to receiving an Initial Demand Request, in which event the Company
     will have the right to defer the filing of such Demand Registration until
     such offering is completed or such time as the Company is no longer
     proceeding diligently to effect such offering (but in no event more than 45
     days (excluding the time needed to respond to SEC comments, conduct a
     roadshow, price and close such offering (provided such closing is within a
     reasonable period of time after the roadshow)); provided, however, that the
     Company may not use the right set forth in this clause (ii) more than once
     in any 12-month period.

          (b) The Company will only be obligated to initiate a Demand
     Registration if the amount of Registrable Securities proposed to be
     registered pursuant to Section 1.1 in the aggregate (i) exceeds 8,000,000
     shares of Original Common Stock in the case of a Traditional Underwriting
     or 3,000,000 shares of Original Common Stock in the case of any Demand
     Registration that is not a Traditional Underwriting and (ii) in the case of
     a Traditional Underwriting, has a good faith estimated public offering
     price (as determined in the reasonable discretion of the Company) of at
     least $100 million ((i) and (ii) together, to the extent applicable, the
     "Minimum Amount").

          (c) The Company will not be required to effect more than three Demand
     Registrations in any 12-month period, only one of which may be a
     Traditional Underwriting. A Demand Registration will be deemed effected
     upon the initial filing of the registration statement related thereto
     unless (i) the Rightsholder elects to terminate it following the Company's
     exercise of any deferral right pursuant to Sections 1.3(a)(ii) or 1.3(d) or
     (ii) the Company fails to comply with its obligations under this Agreement
     with respect to such Demand Registration and a Rightsholder reasonably
     determines, and notifies the Company, that such failure has a material
     adverse effect on such Rightsholder.

          (d) If the Company determines in good faith that the registration and
     distribution of Registrable Securities in a Demand Registration would (i)
     materially impede, delay or interfere with any acquisition, corporate
     reorganization or other significant transaction involving the Company or
     (ii) require disclosure of material non-public information, the disclosure
     of which at that time would materially and adversely affect the Company,
     the Company shall have the right to defer the filing or effectiveness of
     the registration statement relating to such Demand Registration for a
     period of not more than 30 days after receipt of the Initial Demand
     Request; provided, however, that the Company may not use this right more
     than once in any 12-month period.

          (e) The Company shall give notice to the Rightsholders (i) at the
     beginning of any deferral period under this Section 1.3 promptly following
     its receipt of the Initial Demand Notice and (ii) promptly following the
     end of any such deferral period.

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                                   SECTION 2
                        COMPANY "PIGGYBACK" REGISTRATION

     2.1 Registration Rights. If the Company proposes to register (including for
this purpose a registration to be effected by the Company for stockholders other
than the Rightsholders) any shares of Original Common Stock under the Securities
Act in connection with the underwritten public offering of such Securities
solely for cash (other than a registration on Form S-4 or such other forms as
are then prescribed under the Securities Act for the same purposes as such form,
a registration relating solely to the sale of Securities to participants in a
Company compensation, benefit or stock plan or a registration in which the only
Original Common Stock being registered is Original Common Stock issuable upon
conversion of debt or equity Securities that are also being registered), the
Company shall, at that time, promptly give each Rightsholder written notice of
such registration. Upon the written request of each Rightsholder (to the extent
the Company receives such request within 15 days after the Company delivered its
notice of registration under this Section 2), the Company shall, subject to the
provisions of Sections 2.2, 2.3 and 2.4, cause to be registered under the
Securities Act all of the Registrable Securities that each such Rightsholder has
requested to be registered.

     2.2 Underwriting Requirements. If the lead managing underwriter for an
offering advises the Company that the total amount of Securities proposed to be
included in such offering, including by the Company and the Rightsholders,
exceeds the amount of Securities that the lead managing underwriter determines
in its sole discretion is compatible with such offering's success, then the
Company shall have the right to reduce the number of Securities, including
Registrable Securities, included in the offering to a number that the lead
managing underwriter determines in its sole discretion is so compatible. In the
event that a reduction occurs, the amount of Original Common Stock to be
included in the offering will be allocated first, to the Company; second, to the
Rightsholders and all other holders of Securities subject to pari passu
registration rights by reducing the number of Securities each may sell on a
pro-rata basis, based upon the number of shares of Original Common Stock that
each of such Rightsholders and other holders own at such time subject to
registration rights; and third to any other holders of Securities.

     2.3 Rightsholder Right to Withdraw. Each Rightsholder has the right to
withdraw all or any portion of its Registrable Securities from a registration
under Section 2 at any time before the effective date of the applicable
registration statement.

     2.4 Company Right to Withdraw. The Company has the right to withdraw any
registration statement and abandon any proposed offering, subject to Section 2,
without the consent of any Rightsholder, notwithstanding the request of any such
Rightsholder to participate therein in accordance with Section 2, if the Company
determines to do so in its sole discretion.

                                      -4-

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                                   SECTION 3
                         ADDITIONAL COMPANY OBLIGATIONS

     3.1  Whenever required under this Agreement to effect the registration of
any Registrable Securities, the Company shall, as expeditiously as is
commercially reasonably possible (or within any more-specific time period this
Agreement requires):

          (a)  at least five Business Days before filing a registration
     statement, prospectus or any amendments or supplements thereto, furnish to
     the Rightsholders who are participating in such registration statement, the
     underwriters, and a single counsel to all Rightsholders requesting to
     include shares of Registrable Securities in such registration statement
     (which counsel will be selected by the Rightsholder requesting the largest
     number of shares of Registrable Securities to be included in such
     registration statement and be reasonably satisfactory to the Company),
     copies of the registration statement, prospectus or any amendments or
     supplements thereto proposed to be filed. These documents will be subject
     to the review of such Rightsholders, underwriters and counsel, and the
     Company shall use commercially reasonable efforts to take into account,
     and, if appropriate, reflect such comments as such Rightsholders,
     underwriters and counsel reasonably may propose;

          (b)  prepare and file with the SEC a registration statement with
     respect to those Registrable Securities and use its commercially reasonable
     efforts to cause such registration statement to become effective, and keep
     such registration statement effective for a period of at least 45 days (or
     such shorter period during which the distribution contemplated in the
     registration statement is completed);

          (c)  prepare and file with the SEC any amendments and supplements to
     such registration statement and the prospectus used in connection with such
     registration statement as may be necessary to comply with the provisions of
     the Securities Act with respect to the disposition of all Securities such
     registration statement covers and make generally available an earnings
     statement satisfying the provisions of Section 11(a) of the Securities Act
     (except that the Company will be deemed to have complied with this clause
     if it has complied with Rule 158 under the Securities Act);

          (d)  notify the Rightsholders participating in such registration
     statement promptly and (if requested) confirm such notice in writing,

          (i)  when any registration statement, prospectus, prospectus
               supplement or post-effective amendment relating to such
               registration has been filed, and, with respect to such
               registration statement or any post-effective amendment, when the
               same has become effective,

          (ii) of any SEC request for amendments or supplements to such
               registration statement or the related prospectus or for
               additional information regarding Rightsholders,

                                      -5-

<PAGE>

         (iii) of the SEC's issuance of any stop order suspending the
               effectiveness of such registration statement or the initiation of
               any proceedings for such purpose,

         (iv)  of the Company's receipt of any notification with respect to the
               suspension of the qualification or exemption from qualification
               of any of the Registrable Securities for sale in any jurisdiction
               or the initiation or threatening of any proceeding for such
               purpose,

         (v)   of any determination by the Company that any event has occurred
               that requires making any changes in such registration statement,
               prospectus, or documents incorporated (or deemed to be
               incorporated) by reference in any of such documents so that they
               will not contain any untrue statement of a material fact or omit
               to state any material fact that they are required to state or
               that is necessary to make the statements in such documents not
               misleading and

         (vi)  of any determination by the Company that any event has occurred
               that would cause such registration statement or the prospectus
               contained therein not to be usable for resale of the Registrable
               Securities;

         (e)   use reasonable best efforts to obtain the withdrawal of any order
     suspending the effectiveness of such registration statement, or the lifting
     of any suspension of the qualification or exemption from qualification of
     any Registrable Securities for sale in any jurisdiction in the United
     States;

          (f)  furnish to each Rightsholder participating in such registration
     statement, the designated counsel for those Rightsholders, and each
     managing underwriter, if any, without charge, one conformed copy of such
     registration statement, as declared effective by the SEC, and of each
     post-effective amendment to such registration statement, in each case
     including financial statements and schedules, and deliver, without charge,
     the number of copies of the preliminary prospectus, any amended preliminary
     prospectus, each final prospectus and any post-effective amendment or
     supplement to any of such documents, as each Rightsholder may reasonably
     request in order to facilitate its disposition of the Registrable
     Securities included in such registration statement in conformity with the
     Securities Act's requirements;

          (g)  use its reasonable best efforts to register and qualify the
     Securities such registration statement covers under all securities laws or
     Blue Sky laws of United States and Canadian jurisdictions that the
     Rightsholders reasonably request; provided that the Company will not be
     required to qualify generally to do business in any jurisdiction where it
     is not then so qualified or to take any action that would subject it to
     general service of process or taxation in any such jurisdiction where it is
     not then so subject;

          (h)  upon the occurrence of any event contemplated by Section 3.1(d)
     (v) or 3.1(d)(vi), prepare a supplement or post-effective amendment to such
     registration statement or the related prospectus or any document
     incorporated (or deemed to be

                                      -6-

<PAGE>

     incorporated) by reference in such documents and file any other required
     document so that, as thereafter delivered to the purchasers of the
     Registrable Securities being sold under such documents, such documents will
     not contain any untrue statement of a material fact or omit to state any
     material fact required to be stated in such documents or necessary to make
     the statements in such documents, in light of the circumstances under which
     they were made, not misleading;

          (i)  use commercially reasonable efforts to comply with all applicable
     rules and regulations of the SEC, any applicable securities exchange and
     the requirements of the Securities Act;

          (j)  on or before the registration statement's effective date, provide
     the Company's transfer agent for the Registrable Securities with printed
     certificates for the Registrable Securities that such registration
     statement covers in a form eligible for deposit with The Depository Trust
     Company;

          (k)  cause all Registrable Securities registered under this Agreement
     to be listed on each securities exchange that similar Securities are then
     listed on;

          (l)  if an offering is an underwritten offering, make available for
     inspection by any Rightsholder participating in such registration
     statement, any underwriter participating in any offering pursuant to such
     registration statement, the designated counsel for the Rightsholders, any
     counsel to the underwriters, and any accountant or other agent retained by
     any of those Rightsholders or underwriters (collectively, the
     "Inspectors"), financial and other records and information, pertinent
     corporate documents and properties of any of the Company and its Affiliates
     (collectively, the "Records"), as are reasonably necessary to enable them
     to exercise their due diligence responsibilities; provided, however, that
     if the Company determines in good faith that certain Records are
     confidential and so notifies the Inspectors in writing, the Company need
     not disclose such confidential Records to any Inspector unless the
     Inspector signs a confidentiality agreement reasonably satisfactory to the
     Company, which agreement shall permit the release of such confidential
     Records if disclosing such Records is necessary to avoid or correct a
     misstatement or omission in such registration statement or so ordered
     pursuant to a subpoena or other order from a court of competent
     jurisdiction; and

          (m)  if an offering is an underwritten offering, enter into any
     agreements (including an underwriting agreement in form, scope and
     substance as is customary in underwritten offerings, including customary
     lock-up provisions) and take all other customary, appropriate and
     reasonable actions (including in the case of a Traditional Underwriting,
     assisting with the roadshow) that the managing underwriters or
     Rightsholders holding a majority of Registrable Securities included in the
     offering request in connection with such agreements in order to expedite or
     facilitate the disposition of the Registrable Securities included in the
     offering, and in that connection,

          (i)  use its commercially reasonable efforts to obtain opinions (in
               form, scope and substance reasonably satisfactory to the managing
               underwriters' counsel) of the Company's counsel and updates of
               such opinions,

                                      -7-

<PAGE>

               addressed to each of the underwriters, as to the matters
               customarily covered in opinions requested in underwritten
               offerings and any other matters those counsel and underwriters
               reasonably request,

         (ii)  use its commercially reasonable efforts to obtain "cold-comfort"
               letters and updates of such letters from the Company's
               independent certified public accountants (and, if necessary, any
               other independent certified public accountants of any Company
               Affiliate or of any business the Company owns for which financial
               statements and financial data are, or are required to be,
               included in the registration statement), addressed to each of the
               underwriters, such letters to be in customary form and covering
               matters of the type customarily covered in "cold-comfort" letters
               in connection with underwritten offerings and

         (iii) if requested and if an underwriting agreement is entered into,
               provide indemnification provisions and procedures substantially
               to the effect included in Section 6 with respect to all Persons
               to be indemnified pursuant to such Section.

     The Company shall perform its obligations under this Section 3.1(m) at each
     closing under the applicable underwriting or similar agreement, or as and
     to the extent such agreements require.

                                   SECTION 4
                     ADDITIONAL OBLIGATIONS OF RIGHTSHOLDERS

     4.1 General. The Company's obligation to take any action pursuant to this
Agreement with respect to the Registrable Securities of any selling Rightsholder
is conditioned on such Rightsholder (i) furnishing the Company information
regarding itself, its Registrable Securities, and its intended method of
disposing of those Registrable Securities as the Company reasonably requests in
writing to allow the Company to effect the registration of such Rightsholders'
Registrable Securities and (ii) taking all such action as may be reasonably
required in order not to delay the registration and offering of the Securities
by the Company.

     4.2 Participation in Underwritten Registrations. No Rightsholder may
participate in any underwritten registered offering contemplated hereunder
unless such Rightsholder (i) agrees to sell its Registrable Securities on the
basis provided in any underwriting arrangements, which shall be of a customary
nature, and (ii) completes and executes all questionnaires, powers of attorney,
indemnities, underwriting agreements and other documents reasonably required
under the terms of such underwriting arrangements and this Agreement.

     4.3 Discontinuation of Sales Upon Certain Events. Upon receipt of any
notice from the Company pursuant to Section 3.1(d)(v) or 3.1(d)(vi), each
Rightsholder will forthwith discontinue the offer and sale of Registrable
Securities pursuant to the registration statement covering such Registrable
Securities until receipt by such Rightsholder and the underwriters of copies of
the supplemented or amended prospectus contemplated by Section 3(h), or until it
is advised in writing by the Company that the use of the prospectus may be
resumed, and, if so

                                      -8-

<PAGE>

directed by the Company, each Rightsholder will, and will request the
underwriters to, deliver to the Company all copies, other than permanent file
copies, then in its or their possession of the most recent prospectus covering
such Registrable Securities at the time of receipt of such notice.

     4.4 Holdback. Each Rightsholder agrees not to effect any sale (including a
sale pursuant to Rule 144 of the Securities Act) of any Securities, before or
after the effective date of a registration statement filed by the Company with
the SEC for an underwritten offering of equity Securities (except for
Registrable Securities that are included in such registration statement pursuant
to this Agreement) but only if and to the extent the managing underwriter for
such offering requests. However, any limits on Rightsholders' sales (i) shall
not be greater in any way than the limits on the Company's directors, executive
officers and any other significant stockholders who have purchased securities of
the Company directly from the Company and (ii) shall expire within 90 days after
the offering's effective date. Each Rightsholder shall execute and deliver to
the managing underwriter any letter or agreement, which shall be in
substantially the same form as to be delivered by the Company's directors,
executive officers and any applicable significant stockholders of the Company,
that the underwriter may reasonably request to the foregoing effect. Promptly
upon any Rightsholders' request, the Company shall request a waiver of the
Rightsholders' agreement pursuant to this Section 4.4.

                                   SECTION 5
                            EXPENSES OF REGISTRATION

     5.1 The Company shall bear all costs, fees and expenses (excluding
underwriting discounts and commissions and fees and expenses of separate counsel
for the Rightsholders, fees and expenses of any other expert or advisor retained
by or at the request of a Rightsholder, any underwriter or any underwriter's
counsel and out-of-pocket expenses associated with any roadshow) incident to its
performance of or compliance with this Agreement, including all registration,
filing and qualification fees (including qualification with state blue sky laws,
the New York Stock Exchange or any other exchange the Company's Securities are
then listed on), printers' fees and fees and expenses of the Company's
accountants (including the costs of any "cold-comfort" letters) and fees and
expenses of the Company's counsel.

                                   SECTION 6
                                 INDEMNIFICATION

     6.1 Company's Indemnification. To the fullest extent permitted by law, the
Company shall indemnify and hold harmless each Rightsholder, each underwriter
(as defined in the Securities Act) for the Rightsholders, each Person, if any,
who controls each Rightsholder or each underwriter within the meaning of the
Securities Act, and each of their respective constituent partners, members,
employees, agents, contractors, officers and directors against any losses,
claims, damages, fines, penalties, assessments by public agencies, settlement,
costs and expenses (including costs of preparation and reasonable attorneys'
fees) and other liabilities (any of the foregoing being a "Loss") that relate in
any way to any Violation. The Company shall pay to each Person entitled to
indemnification under this Section 6.1 the amount of Losses they incur as they
incur such Losses. However, the Company will not need to pay any indemnified
Person the amount of (i) Losses that are settlement payments if such indemnified
Person makes the settlement without the Company's consent (so long as the
Company did not unreasonably

                                      -9-

<PAGE>

withhold its consent), or (ii) Losses to the extent such Losses arise out of a
Violation that occurs because the Company relied on written information about
the indemnified Person that the indemnified Person furnished to the Company
expressly for the Company to use in connection with the applicable registration
or (iii) Losses, in the case of any Person who participates as an underwriter in
the offering or sale of Registrable Shares or any other Person, if any, who
controls such underwriter within the meaning of the Securities Act, or any
constituent partner, member, employee, agent, contractor, officer or director of
any such underwriter, in any such case to the extent such Losses arise out of
such underwriter's failure to send or give a copy of the final prospectus, as
the same may be then supplemented or amended, to the Person asserting an untrue
statement or alleged untrue statement or omission or alleged omission at or
prior to the written confirmation of the sale of Registrable Shares to such
Person if such statement or omission was corrected in such final prospectus.

     6.2 Rightsholders' Indemnification. To the fullest extent permitted by law,
each selling Rightsholder (severally but not jointly) shall indemnify and hold
harmless the Company, each underwriter (as defined in the Securities Act), each
other Rightsholder participating in a registration statement, each Person, if
any, who controls the Company, underwriter, or other participating Rightsholder
within the meaning of the Securities Act and each of their respective
constituent partners, members, employees, agents, contractors, officers and
directors against any Losses to the extent such Losses arise out of a Violation
that occurs because the Company relied on written information about the
indemnifying Rightsholder that the indemnifying Rightsholder furnished to the
Company expressly for the Company to use in connection with the applicable
registration. Each indemnifying Rightsholder shall pay each Person entitled to
indemnification under this Section 6.2 the amount of Losses they incur as they
incur a Loss. However, the indemnifying Rightsholder will not need to pay (i)
any indemnified Person the amount of Losses that are settlement payments if such
indemnified Person makes the settlement without the indemnifying Rightsholders'
consent (so long as the indemnifying Rightsholder did not unreasonably withhold
its consent) and (ii) any amount of Losses under this Section 6.2, Section 6.4,
or under such sections together, that exceeds the net proceeds such indemnifying
Rightsholder received from the offering that the Violation arises out of.

     6.3 Additional Procedures. Promptly after a Person entitled to
indemnification under this Section 6 receives notice that it might be subject to
Losses, such indemnified Person shall notify the indemnifying Person in writing
regarding such potential Losses. The indemnifying Person will have the right to
participate in, and, jointly with any other indemnifying Person, to assume the
defense against such Losses with one counsel selected by the indemnifying
Person, subject to the consent of the indemnified Person (which shall not be
unreasonably withheld). If a conflict of interest exists or develops that would
prohibit one counsel from representing both the indemnifying Person and the
indemnified Person, then the indemnified Person (together with all other
indemnified Persons that one counsel can represent without a conflict of
interest) will have the right to retain one separate counsel of their own
choosing, with the indemnifying Person paying all the fees and expenses. Except
in the event of a conflict of interest, if the indemnifying Person notifies the
indemnified Person that it has elected, and then promptly begins, to defend the
indemnified Person against Losses, the indemnifying Person will not be liable to
such indemnified Person for any legal expenses such indemnified Person
subsequently incurs in connection with such defense. If the indemnifying Person
elects to assume the defense against any Losses, the indemnifying Person shall
allow the indemnified Person to continue to

                                      -10-

<PAGE>

participate in defending against such Losses (at the expense of the indemnified
Person) if the indemnified Person so chooses. The indemnified Person's failure
to notify the indemnifying Person within a reasonable time regarding Losses will
not relieve the indemnifying Person of any liability to the indemnified Person
under this Section 6 except to the extent such failure to notify materially
prejudices the indemnifying Person's ability to defend against such Losses. In
defending against Losses, an indemnifying Person shall not consent to entry of
any judgment regarding, or otherwise settle, any claim involving Losses unless
(x) the indemnified Person has approved in writing the judgment or other
settlement or (y) the judgment or other settlement includes the claimant's
unconditional release of the indemnified Person from all liability related to
that claim.

         6.4 Unavailability. If a court of competent jurisdiction holds that the
indemnification under this Section 6 is unavailable to an indemnified Person
with respect to any Losses, then the indemnifying Person, in lieu of
indemnifying such indemnified Person, shall contribute to the amount the
indemnified Person must pay in connection with such Losses the appropriate
proportion to reflect the indemnifying Person's relative fault in connection
with such Losses. The indemnifying and indemnified Persons shall determine the
indemnifying Person's and indemnified Person's relative fault based on, among
other things, which Person supplied information relating to the untrue or
alleged untrue statement of a material fact or the omission to state a material
fact and the Person's relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.

         6.5 Conflict With Underwriting Agreement. Notwithstanding anything to
the contrary in Section 6, to the extent (but only to the extent) that the
underwriting agreement's provisions on indemnification and contribution conflict
with the provisions of Section 6, the underwriting agreement's provisions will
control.

         6.6 Survival. The Company's and Rightsholders' obligations under
Section 6 will survive (i) the completion of any offering of Registrable
Securities in a registration statement under this Agreement and (ii) this
Agreement's termination.

                                    SECTION 7
                                    RULE 144

         7.1 The Company covenants that it will file the reports required to be
filed by it under the Securities Act and the Exchange Act and the rules and
regulations adopted by the SEC thereunder (or, if the Company is not required to
file such reports, it will, upon the request of any Rightsholder, make publicly
available other non-confidential information so long as necessary to permit
sales under Rule 144 under the Securities Act), and it will take such other
action as any Rightsholder may reasonably request, all to the extent required
from time to time to enable such Rightsholder to sell Registrable Securities
without registration under the Securities Act within the limitation of the
exemptions provided by (a) Rule 144 under the Securities Act or (b) any similar
rule or regulation hereafter adopted by the SEC. Upon the request of any
Rightsholder, the Company will deliver to such Rightsholder a written statement
as to whether it has complied with such requirements.

                                      -11-

<PAGE>

                                   SECTION 8
                        ASSIGNMENT OF REGISTRATION RIGHTS

         8.1  A Rightsholder may assign its rights under this Agreement only in
connection with a Permitted Transfer pursuant to which the assignee executes a
written agreement reasonably satisfactory to the Company whereby the assignee
agrees to assume all of the obligations of such Rightsholder hereunder and to be
bound by all of the terms, conditions and restrictions set forth in this
Agreement. A Rightsholder's assignment of any rights under this Section 8 will
pertain only to the Registrable Securities and Derivative Securities that such
Rightsholder transfers so that such Rightsholder will retain any rights it held
prior to such transfer under this Agreement with respect to any Registrable
Securities and Derivative Securities that such Rightsholder continues to own.

                                   SECTION 9
                       TERMINATION OF REGISTRATION RIGHTS

         9.1  The right of any specific Rightsholder to request registration or
to include Registrable Securities in any registration pursuant to this Agreement
will terminate when such Rightsholder ceases to hold Registrable Securities or
Derivative Securities convertible or exercisable for Registrable Securities.
Notwithstanding the termination as to any specific Rightsholder, this Agreement
shall remain in effect for all other Rightsholders holding Registrable
Securities or Derivative Securities convertible or exercisable for Registrable
Securities.

                                   SECTION 10
                  LIMITATIONS ON SUBSEQUENT REGISTRATION RIGHTS

         10.1 From and after the date of this Agreement, the Company shall not,
without the prior written consent of the Rightsholders holding at least a
majority of the Registrable Securities then outstanding (but giving effect, for
the purposes of such calculation and consent, to the issuance of Registrable
Securities pursuant to the exercise or conversion of then exercisable or
convertible Derivative Securities), enter into any agreement with any holder or
prospective holder of any Securities granting registration rights with respect
to such Securities that would be superior to those granted under this Agreement.

                                   SECTION 11
                                  MISCELLANEOUS

         11.1 Successors and Assigns. Except as provided in Section 8.1, no
Rightsholder may otherwise assign or delegate any of its rights or obligations
under this Agreement without the prior written consent of the Company, which
consent shall be in the sole and absolute discretion of the Company. Any
purported assignment or delegation without such consent and any purported
assignment by a Rightsholder that does not comply with the terms of Section 8.1
shall be void and ineffective. Except as may be expressly provided herein, this
Agreement shall be binding upon and inure to the benefit of the successors of
each of the Parties.

                                      -12-

<PAGE>

         11.2 Benefits of Agreement Restricted to Parties. This Agreement is
made solely for the benefit of the Parties, and no other Person (including each
Party's employees or stockholders) shall have any right, claim or cause of
action under or by virtue of this Agreement.

         11.3 Notices. All notices, requests and other communications
(collectively, the "Notices") made pursuant to this Agreement shall be in
writing and signed and correctly dated by the Party sending such Notice. All
Notices shall be delivered personally (by courier or otherwise) or by facsimile
to the receiving Party at the applicable address or facsimile number set forth
below:

                  If to the Company:

                           Lyondell Chemical Company
                           1221 McKinney Street, Suite 700
                           Houston, Texas 77010
                           Attention: Gerald A. O'Brien
                           Telecopy Number:  713-309-7312

                           with a copy to:

                           Baker Botts L.L.P.
                           910 Louisiana Street
                           Houston, Texas  77002
                           Attention:  Stephen A. Massad
                           Telecopy Number:  713-229-1522

                           and

                           Lyondell Chemical Company
                           1221 McKinney Street, Suite 700
                           Houston, Texas 77010
                           Attention: General Counsel
                           Telecopy Number:  713-652-4538

                  If to an OCHC Party:

                           such party
                           c/o Occidental Chemical Holding Corporation
                           5005 LBJ Freeway
                           Dallas, TX 75244
                           Attention: General Counsel
                           Telecopy Number: 972-404-4155

Any Notice delivered personally shall be deemed to have been given on the date
it is so delivered, or upon attempted delivery if acceptance of delivery is
refused, and any Notice delivered by facsimile shall be deemed to have been
given on the first Business Day it is received by the addressee (or, if such
Notice is not received during regular business hours of a

                                      -13-

<PAGE>

Business Day, at the beginning of the next such Business Day). The address and
facsimile numbers set forth above may be changed by a Party by giving Notice of
such change of address or facsimile number in the manner set forth in this
Section 11.3.

         11.4 Severability. In the event that any provision of this Agreement
shall finally be determined to be unlawful, such provision shall be deemed
severed from this Agreement and every other provision of this Agreement shall
remain in full force and effect.

         11.5 Entire Agreement. This Agreement together with the Related
Securities Agreements sets forth the entire agreement and understanding among
the Parties as to the subject matter hereof and merges with and supercedes all
prior discussions, agreements and understandings of every kind and nature among
them.

         11.6 Construction. In construing this Agreement, the following
principles shall be followed: (i) no consideration shall be given to the
captions of the sections or clauses, which are inserted for convenience in
locating the provisions of this Agreement and not as an aid in construction;
(ii) no consideration shall be given to the fact or presumption that any of the
Parties had a greater or lesser hand in drafting this Agreement; (iii) the word
"includes" and its syntactic variants mean "includes, but is not limited to" and
corresponding syntactic variant expressions; (iv) the plural shall be deemed to
include the singular, and vice versa; (v) references in this Agreement to
Sections and Appendix shall be deemed to be references to Sections of, and the
Appendix to, this Agreement unless the context shall otherwise require; (vi) the
words "hereof", "herein" and "hereunder" and words of similar import shall refer
to this Agreement as a whole and not to any particular provision of this
Agreement; (vii) references to a Person are also to its permitted successors and
permitted assigns; (viii) the Appendix attached to this Agreement shall be
deemed incorporated herein as if set forth in full herein; and (ix) unless
otherwise expressly provided, any agreement, instrument or statute defined or
referred to herein means such agreement, instrument or statute as from time to
time amended, modified or supplemented, including (in the case of agreements or
instruments) by waiver or consent and (in the case of statutes) by succession of
comparable successor statutes and references to all attachments thereto and
instruments incorporated therein.

         11.7 Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall constitute an original, and all of which when
taken together shall constitute one and the same original document.

         11.8 Governing Law. The laws of the State of Delaware shall govern the
construction, interpretation and effect of this Agreement without giving effect
to any conflicts of law principles.

         11.9 Amendment. This Agreement may be amended, and the provisions
hereof may be waived, only by a written instrument signed by (i) the
Rightsholders of a majority of the Registrable Securities outstanding as of the
date of such determination and (ii) the Company; provided, however, that no
amendment to this Agreement may be made that materially and adversely affects
the rights of any Rightsholder under this Agreement without the express written
consent of such Rightsholder. The waiver by any Party of a breach of any
provision of this Agreement shall not operate or be construed as a waiver of any
subsequent breach.

                                      -14-

<PAGE>

         11.10 Recapitalizations, Exchanges, etc. The provisions of this
Agreement shall apply, to the full extent set forth herein with respect to the
Registrable Securities, to any and all shares of equity capital of the Company
or any successor or assign of the Company (whether by merger, consolidation,
sale of assets or otherwise) that may be issued in respect of, in exchange for,
or in substitution of the Registrable Securities, in each case as the amounts of
such securities outstanding are appropriately adjusted for any equity dividends,
stock splits, reverse stock splits, combinations, recapitalizations and the like
occurring after the date of this Agreement.

         11.11 Jurisdiction; Consent to Service of Process; Waiver. ANY JUDICIAL
PROCEEDING BROUGHT AGAINST ANY PARTY OR ANY DISPUTE UNDER OR ARISING OUT OF OR
IN CONNECTION WITH THIS AGREEMENT SHALL BE BROUGHT IN THE FEDERAL OR STATE
COURTS OF THE STATE OF DELAWARE, AND, BY EXECUTION AND DELIVERY OF THIS
AGREEMENT, EACH OF THE PARTIES ACCEPTS THE EXCLUSIVE JURISDICTION OF SUCH COURTS
AND IRREVOCABLY AGREES TO BE BOUND BY ANY JUDGMENT (AS FINALLY ADJUDICATED)
RENDERED THEREBY IN CONNECTION WITH THIS AGREEMENT. EACH OF THE PARTIES SHALL
APPOINT THE CORPORATION TRUST COMPANY, THE PRENTICE-HALL CORPORATION SYSTEM,
INC. OR A SIMILAR ENTITY (THE "AGENT") AS AGENT TO RECEIVE ON ITS BEHALF SERVICE
OF PROCESS IN ANY PROCEEDING IN ANY SUCH COURT IN THE STATE OF DELAWARE, AND
EACH OF THE PARTIES SHALL MAINTAIN THE APPOINTMENT OF SUCH AGENT (OR A
SUBSTITUTE AGENT) FROM THE DATE HEREOF UNTIL THE EARLIER OF THE CLOSING DATE OR
THE TERMINATION OF THIS AGREEMENT AND SATISFACTION OF ALL OBLIGATIONS HEREUNDER.
THE FOREGOING CONSENTS TO JURISDICTION AND APPOINTMENTS OF AGENT TO RECEIVE
SERVICE OF PROCESS SHALL NOT CONSTITUTE GENERAL CONSENTS TO SERVICE OF PROCESS
IN THE STATE OF DELAWARE FOR ANY PURPOSE EXCEPT AS PROVIDED ABOVE AND SHALL NOT
BE DEEMED TO CONFER RIGHTS ON ANY PERSON OTHER THAN THE PARTIES. EACH PARTY
HEREBY WAIVES ANY OBJECTION IT MAY HAVE BASED ON LACK OF PERSONAL JURISDICTION,
IMPROPER VENUE OR FORUM NON-CONVENIENS.

         11.12 Waiver of Jury Trial. EACH PARTY HEREBY KNOWINGLY AND
INTENTIONALLY, IRREVOCABLY AND UNCONDITIONALLY WAIVES TRIAL BY JURY IN ANY LEGAL
ACTION OR PROCEEDING ARISING OUT OF OR IN CONNECTION WITH THIS AGREEMENT AND FOR
ANY COUNTERCLAIM THEREIN.

                                      -15-

<PAGE>

          IN WITNESS WHEREOF, this Registration Rights Agreement has been
executed on behalf of each of the Parties by their respective officers thereunto
duly authorized and was effective as of the date first written above.

                                         LYONDELL CHEMICAL COMPANY

                                         By: /s/ T. KEVIN DENICOLA
                                             -----------------------------------
                                             Name: T. Kevin DeNicola
                                             Title: Senior Vice President and
                                                    Chief Financial Officer

                                         OCCIDENTAL CHEMICAL HOLDING CORPORATION

                                         By: /s/ JAMES R. HAVERT
                                             -----------------------------------
                                             Name: James R. Havert
                                             Title: Vice President and Treasurer

<PAGE>

                                  APPENDIX "A"

                            GLOSSARY OF DEFINED TERMS

     "Affiliate" shall mean any Person that, directly or indirectly, through one
or more intermediaries, controls, is controlled by, or is under common control
with the Person specified. For purposes of this definition, the term "control"
shall have the meaning set forth in 17 CFR 230.405, as in effect on the date
hereof.

     "Agent" shall have the meaning set forth in Section 11.11.

     "Agreement" shall have the meaning set forth in the Preamble.

     "Business Day" shall mean any day on which the New York Stock Exchange,
Inc. is open for trading.

     "Company" shall have the meaning set forth in the Preamble.

     "Company Notice" shall have the meaning set forth in Section 1.1(a).

     "Contingent Payment Amount" shall have the meaning set forth in the
Securities Purchase Agreement.

     "Demand Registration" shall have the meaning set forth in Section 1.1.

     "Derivative Securities" shall mean the Warrant and shares of the Series B
Common Stock.

     "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended,
and the SEC's rules and regulations promulgated thereunder.

     "Initial Demand Request" shall have the meaning set forth in Section 1.1.

     "Inspectors" shall have the meaning set forth in Section 3.1(l).

     "Loss" shall have the meaning set forth in Section 6.1.

     "Minimum Amount" shall have the meaning set forth in Section 1.3(b).

     "Notice" shall have the meaning set forth in Section 11.3.

     "Occidental" shall have the meaning set forth in the Recitals.

     "Original Common Stock" shall mean each share of common stock, par value
$1.00 per share, of the Company (excluding any share of Series B Common Stock).

     "OCHC" shall have the meaning set forth in the Preamble.

     "OCHC Party" shall mean OCHC or any of its Affiliates.

                                       A-1

<PAGE>

     "Party" shall mean the Company and, at the time of determination, any
Rightsholder.

     "Permitted Transfer" shall mean a transfer of Registrable Securities or
Derivative Securities (which continue to be, or continue to be convertible into
or exercisable for, Registrable Securities immediately following that transfer)
permitted by and made in accordance with the Stockholder Agreement that either
(i) is to the applicable Rightsholder's Wholly Owned Affiliate or (ii) relates
to, in the aggregate, not less than 5,000,000 shares of Original Common Stock.

     "Person" shall mean any natural person, corporation, partnership, limited
liability company, joint venture, association or other entity or organization.

     "Securities Purchase Agreement" shall have the meaning set forth in the
Recitals.

     "Records" shall have the meaning set forth in Section 3.1(l).

     "register", "registered", and "registration" refer to a registration
effected by preparing and filing a registration statement or similar document in
compliance with the Securities Act, and the SEC's declaration or ordering of
effectiveness of that registration statement or document.

     "Registrable Securities" shall mean all shares of Original Common Stock
issued (i) upon exercise of a Warrant, (ii) as payment of a Contingent Payment
Amount or (iii) as a dividend or other distribution with respect to, in exchange
for, upon the conversion of or in replacement of any share of Series B Common
Stock, excluding in each case (A) any Registrable Securities a Rightsholder
sells, or Registrable Securities issued upon the conversion or exercise of
Derivative Securities a Rightsholder sells, in either case in a transaction in
which the rights of that Rightsholder under Section 8 are not permitted to be
assigned as provided in Section 8, (B) any Registrable Securities after those
Securities have been sold to the public pursuant to a registration statement
covering such Securities that has been declared effective under the Securities
Act, (C) any Registrable Securities that have been distributed to the public
pursuant to Rule 144 (or any successor provision) under the Securities Act and
(D) any Registrable Securities that have been otherwise transferred, new
certificates for which not bearing a legend restricting further transfer shall
have been delivered by the Company and subsequent disposition of which shall not
require registration under the Securities Act.

     "Related Securities Agreements" shall mean the Securities Purchase
Agreement, the Stockholder Agreement and the Warrant.

     "Rightsholder" shall mean OCHC or any Person that, at the time of
determination, has signed an agreement assuming OCHC's, or a permitted
transferee's, rights and obligations pursuant to Section 8, but only if OCHC or
that Person (as applicable) then owns Registrable Securities or Derivative
Securities convertible into or exercisable for Registrable Securities.

     "SEC" shall mean the Securities and Exchange Commission.

     "Securities" shall mean all of the Company's capital stock and other
authorized or outstanding options, offers, warrants, calls, subscriptions,
rights, convertible notes or other securities (whether debt, equity, or a
combination of debt and equity) as defined in the Securities Act.

                                       A-2

<PAGE>

     "Securities Act" shall mean the Securities Act of 1933, as amended, and the
SEC's rules and regulations promulgated thereunder.

     "Series B Common Stock" shall mean shares of Series B Common Stock, $1.00
par value, of the Company.

     "Stockholder Agreement" shall have the meaning set forth in the Recitals.

     "Subsidiary" shall mean, with respect to any Party, any Person of which
such Party, either directly or indirectly, owns 50% or more of the equity or
voting interests.

     "Traditional Underwriting" shall mean an underwritten offering of shares of
Original Common Stock pursuant to an underwriting agreement and involving
marketing efforts on the part of officers of the Company in the form of a
roadshow.

     "Violation" shall mean (i) any untrue statement or alleged untrue statement
of a material fact contained in any registration statement that includes
Registrable Securities, including any preliminary prospectus or final prospectus
contained in that registration statement or any amendments or supplements to
that registration statement or prospectus or (ii) the omission or alleged
omission to state in that registration statement a material fact (A) required to
be stated in it or (B) necessary to make the statements in that registration
statement in light of the circumstances in which they were made not misleading.

     "Warrant" shall have the meaning set forth in the Recitals.

     "Warrant Shares" shall mean any share of Original Common Stock issued upon
the exercise in whole or in part of a Warrant (including any share of Original
Common Stock issued as Net Payment Shares (as defined in the Warrant)).

                                       A-3<PAGE>

                                                                     EXHIBIT 4.4

                          AMENDMENT TO RIGHTS AGREEMENT

     Amendment, dated as of August 22, 2002, to the Rights Agreement, dated as
of December 8, 1995 (the "Rights Agreement"), between Lyondell Chemical Company
(formerly Lyondell Petrochemical Company), a Delaware corporation (the
"Company"), and The Bank of New York, a New York banking corporation, as Rights
Agent (the "Rights Agent").

     WHEREAS, the Company and the Rights Agent entered into the Rights Agreement
specifying the terms of the Rights (as defined therein);

     WHEREAS, the Company desires to amend the Rights Agreement in accordance
with Section 27 of the Rights Agreement to, among other things, provide for the
issuance of one Right (as such number may be adjusted pursuant to the provisions
of Section 11(p) of the Rights Agreement, as amended hereby) for each share of
Series B Common Stock (as hereinafter defined) issued prior to the earlier of
the Distribution Date and the Expiration Date, and, in certain circumstances
provided for in Section 22 hereof, after the Distribution Date, so that the
holders of Series B Common Stock are in the same position with respect to the
issuance of Rights as they would have been had they been issued Common Stock in
lieu of Series B Common Stock;

     NOW, THEREFORE, in consideration of the premises and mutual agreements set
forth herein and in the Rights Agreement, the parties hereby agree as follows:

     Section 1. Definitions. Capitalized terms used and not otherwise defined
herein shall have the meaning assigned to such terms in the Rights Agreement.

     Section 2. Amendments to Rights Agreement. The Rights Agreement is hereby
amended as set forth in this Section 2.

     (a)  The definition of "Acquiring Person" in Section 1 of the Rights
          Agreement is amended in its entirety to read as follows:

          "Acquiring Person" shall mean any Person who or which, together with
          all Affiliates and Associates of such Person, shall be the Beneficial
          Owner of 15% or more of the shares of Common Equity then outstanding,
          but shall not include any Exempt Person; provided, however, that a
          Person shall not be or become an Acquiring Person if such Person,
          together with its Affiliates and Associates, shall become the
          Beneficial Owner of 15% or more of the shares of Common Equity then
          outstanding solely as a result of a reduction in the number of shares
          of Common Equity outstanding due to the repurchase of Common Equity by
          the Company, unless and until such time as such Person or any
          Affiliate or Associate of such Person shall purchase or otherwise
          become the Beneficial Owner of additional shares of Common Equity,
          constituting 1% or more of the then outstanding

<PAGE>

          shares of Common Equity, or any other Person (or Persons) who is (or
          collectively are) the Beneficial Owner(s) of shares of Common Equity,
          constituting 1% or more of the then outstanding shares of Common
          Equity, shall become an Affiliate or Associate of such Person, unless,
          in either such case, such Person, together with its Affiliates and
          Associates, is not then the Beneficial Owner of 15% or more of the
          shares of Common Equity then outstanding; and provided, further, that,
          notwithstanding anything in this definition of "Acquiring Person" to
          the contrary, if, as of the date hereof, any Person, together with any
          of his or its Affiliates or Associates, is the Beneficial Owner of a
          number of shares of Common Equity that would otherwise cause such
          Person to be an Acquiring Person, such Person shall not be or become
          an Acquiring Person, unless and until such time as such Person or any
          Affiliate or Associate of such Person shall purchase or otherwise
          become the Beneficial Owner(s) of additional shares of Common Equity,
          constituting 1% or more of the then outstanding shares of Common
          Equity, or any other Person (or Persons) who is (or are) the
          Beneficial Owner(s) of shares of Common Equity, constituting 1% or
          more of the then outstanding shares of Common Equity, shall become an
          Affiliate or Associate of such Person, unless, upon becoming the
          Beneficial Owner of such additional shares of Common Equity, such
          Person, together with its Affiliates and Associates, is not then the
          Beneficial Owner of 15% or more of the shares of Common Equity
          outstanding; and provided, further, that if the Board of Directors
          determines in good faith that any Person that would otherwise be an
          "Acquiring Person" is an Inadvertent Acquiring Person, then such
          Person shall not be deemed to be or to have become an "Acquiring
          Person" for any purposes of this Agreement.

               At any time that the Rights are redeemable, the Board of
          Directors may, with respect to any specified Person or Persons,
          determine to increase to a specified percentage or amount greater than
          that set forth herein or decrease to a specified percentage or amount
          lower than that set forth herein (but not lower than the percentage or
          amount of Common Equity then beneficially owned by such Person), the
          level of Beneficial Ownership of Common Equity at which such Person or
          Persons becomes an Acquiring Person.

               For purposes of this definition of "Acquiring Person," any
          calculation of a percentage of Common Equity beneficially owned by any
          Person shall include (i) in the numerator, the number of shares of
          Common Stock, Series B Common Stock and any other series of Common
          Equity held by such Person and (ii) in the denominator, the aggregate
          number of all outstanding shares of Common Equity (including Common
          Stock, Series B Common Stock and any other series of Common Stock of
          the Company outstanding).

                                       2

<PAGE>

     (b)  The words "Common Stock" in Section 1 of the Rights Agreement in the
          definition of " Associate" and "Permitted Offer" and in Sections 2,
          3(a), 3(c), 11(a)(ii)(2), 11(p), 12, 13(a)(y), 15, 16, 18, 21, 22,
          23(b), 25(b), 26, 27, 29 and 30 of the Rights Agreement shall be
          amended and replaced with the words "Common Equity."

     (c)  The following definitions shall be added to Section 1 of the Rights
          Agreement:

          "Series B Common Stock" shall mean the Company's Series B Common
          Stock, par value $1.00 per share.

          "Common Equity" shall mean the Company's Common Stock and Series B
          Common Stock and any other series of Common Stock of the Company
          issued and outstanding after the Record Date and prior to the earlier
          of the Distribution Date or the Expiration Date.

          "Inadvertent Acquiring Person" shall mean a Person that would
          otherwise be an "Acquiring Person" because of such Person's beneficial
          ownership of Common Equity, if either:

          (i)  (a) such Person has reported or is required to report ownership
               of Common Equity on Schedule 13G under the Exchange Act (or any
               comparable or successor report) or on Schedule 13D under the
               Exchange Act (or any comparable or successor report), which
               Schedule 13D, or any amendment thereto, does not state any
               intention to or reserve the right to control or influence the
               management or policies of the Company or engage in any of the
               actions specified in Item 4 of Schedule 13D (other than the
               disposition of the Common Equity), (b) such Person is not the
               Beneficial Owner of 20% or more of the shares of Common Equity
               then outstanding, and (c) after becoming aware that such Person
               has become the Beneficial Owner of 15% or more of the shares of
               Common Equity then outstanding, such Person thereafter, while the
               Beneficial Owner of 15% or more of the shares of Common Equity
               then outstanding does not purchase or otherwise become the
               Beneficial Owner of additional Common Equity or become an
               Affiliate or Associate of any other Person (or Persons) who is
               (or collectively are) the Beneficial Owner of Common Equity; or

          (ii) the Board of Directors, with the concurrence of a majority of the
               members of the Board of Directors who are not, and are not
               representatives, nominees, Affiliates or Associates of, such
               Person or an Acquiring Person, determines in good faith that such
               Person that would otherwise be an "Acquiring Person" has become
               such inadvertently (including, without limitation, because (a)
               such Person was unaware that it beneficially owned Common Equity
               that would otherwise cause such Person to be an "Acquiring

                                       3

<PAGE>

               Person" or (b) such Person was aware of the extent of its
               Beneficial Ownership of Common Equity but had no actual knowledge
               of the consequences of such Beneficial Ownership under this
               Agreement) and without any intention of changing or influencing
               control of the Company, and such Person as promptly as
               practicable divested or divests itself of Beneficial Ownership of
               a sufficient number of Common Equity so that such Person would no
               longer be an "Acquiring Person."

     Section 3. Miscellaneous.

     (a)  The term "Agreement" as used in the Rights Agreement shall be deemed
          to refer to the Rights Agreement as amended hereby.

     (b)  The foregoing amendment shall be effective as of the date first above
          written, and, except as set forth herein, the Rights Agreement shall
          remain in full force and effect and shall be otherwise unaffected
          hereby.

     (c)  This Amendment may be executed in two or more counterparts, each of
          which shall be deemed to be an original, but all for which together
          shall constitute one and the same instrument.

     (d)  This Amendment shall be deemed to be a contract made under the laws of
          the State of Delaware and for all purposes shall be governed by and
          construed in accordance with the laws of such State applicable to
          contracts to be made and performed entirely within such State.

     IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the day and year first above written.

                                     LYONDELL CHEMICAL COMPANY

                                     By:   /s/ GERALD A. O'BRIEN
                                           ---------------------------------
                                           Name:  Gerald A. O'Brien
                                           Title: Vice President and Deputy
                                                  General Counsel

                                     THE BANK OF NEW YORK

                                     By:   /s/ STEVEN MYERS
                                           ---------------------------------
                                           Name:  Steven Myers
                                           Title: Assistant Vice President

                                       4

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