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                                                                   EXHIBIT 10.OO


                       LIMITED LIABILITY COMPANY AGREEMENT
                                       OF
                          CAMDEN PLANT HOLDING, L.L.C.

                      A DELAWARE LIMITED LIABILITY COMPANY

                                    PREAMBLE

         The undersigned sole member, MESQUITE INVESTORS, L.L.C., a Delaware
limited liability company (the "Member"), hereby forms CAMDEN PLANT HOLDING,
L.L.C., a Delaware limited liability company (the "Company"), pursuant to and in
accordance with the Delaware Limited Liability Company Act, 6 Del. C. Sections
18-101, et seq. (the "Act"), and hereby declares the following to be the Limited
Liability Company Agreement (the "Agreement") of the Company as of the Effective
Date (as defined herein).

                                    ARTICLE I
                              DEFINITIONS AND TERMS

         SECTION 1.01. Definitions. Unless the context otherwise requires, the
following terms shall have the following meanings for the purposes of this
Agreement:

                  "ACT" means the Delaware Limited Liability Company Act, 6 Del
C. Sections 18-101, et seq., as amended from time to time (or any corresponding
provisions of succeeding law).

                  "AGREEMENT" means this Limited Liability Company Agreement, as
the same may be amended from time to time.

                  "ASSETS" means, at any time, any real property and other
assets owned or leased by the Company from time to time.

                  "CAPITAL CONTRIBUTION" means a capital contribution made by
the Member pursuant to Section 3.01 or 3.02.

                  "CERTIFICATE" means the Certificate of Formation filed with
the Secretary of State of Delaware on January 6, 2003 to form the Company
pursuant to the Act, as originally executed by Kevin Medill (as an authorized
person within the meaning of the Act) and as amended, modified, supplemented or
restated from time to time, as the context requires.

                  "COMPANY" means the limited liability company formed pursuant
to this Agreement.

                  "DISTRIBUTABLE CASH" means cash (in U.S. dollars) of the
Company that the Member determines is available for distribution.

                  "EFFECTIVE DATE" has the meaning set forth in Section 2.02
hereof.


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                  "INTEREST" means the ownership interest in the Company at any
time, including the right of the Member to any and all benefits to which the
Member may be entitled as provided in this Agreement, together with the
obligations of the Member to comply with all the terms and provisions of this
Agreement.

                  "MEMBER" means Mesquite Investors, L.L.C. and any other member
or members admitted to the Company in accordance with this Agreement or any
amendment or restatement hereof.

                  "PERSON" has the meaning set forth in the Act.

         SECTION 1.02. Terms Generally. The definitions in Section 1.01 shall
apply equally to both the singular and plural forms of the terms defined.
Whenever the context may require, any pronoun shall include the corresponding
masculine, feminine and neuter forms. All references herein to Articles,
Sections and Exhibits shall be deemed to be references to Articles and Sections
of, and Exhibits to, this Agreement unless the context shall otherwise require.
The words "include", "includes" and "including" shall be deemed to be followed
by the phrase "without limitation."

                                   ARTICLE II
                                    FORMATION

         SECTION 2.01. Name. The name of the Company shall be as set forth in
the Preamble hereof. All business of the Company shall be conducted under such
name and title to all property, real, personal, or mixed, owned by or leased to
the Company shall be held in such name. Notwithstanding the preceding sentence,
the Member may change the name of the Company or adopt such trade or fictitious
names as it may determine.

         SECTION 2.02. Term. The term of the Company commenced on the date of
filing of the Certificate of Formation of the Company in the Office of the
Secretary of State of Delaware (the "Effective Date") and, pursuant to Section
18-201(d) of the Act, this Agreement shall be effective as of the Effective
Date. The term of the Company shall continue until terminated as provided in
Article VIII hereof.

         SECTION 2.03. Principal Place of Business. The principal place of
business of the Company shall be located at 1001 Louisiana Street, Houston,
Texas 77002. The Member may establish other offices at other locations.

         SECTION 2.04. Agent for Service of Process. The Corporation Trust
Company shall be the registered agent of the Company upon whom process against
it may be served. The address of such agent within the State of Delaware is:
Corporation Trust Center, 1209 Orange Street, City of Wilmington, County of New
Castle, Delaware 19801.

         SECTION 2.05. Purposes of the Company. The Company has been organized
to engage in any lawful act or activity for which a Delaware limited liability
company may be formed.


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                                   ARTICLE III
                              CAPITAL CONTRIBUTIONS

         SECTION 3.01. Capital Contribution. The Member may contribute cash or
other property to the Company as it shall decide, from time to time.

         SECTION 3.02. Additional Capital Contributions. If at any time the
Member shall determine that additional funds or property are necessary or
desirable to meet the obligations or needs of the Company, the Member may make
additional Capital Contributions.

         SECTION 3.03. Limitation on Liability. The liability of the Member
shall be limited to its Interest in the Company, and the Member shall not have
any personal liability to contribute money to, or in respect of, the liabilities
or the obligations of the Company, except as set forth in the Act.

         SECTION 3.04. Withdrawal of Capital; Interest. The Member may not
withdraw capital or receive any distributions, except as specifically provided
herein. No interest shall be paid by the Company on any Capital Contributions.

                                   ARTICLE IV
                                  DISTRIBUTIONS

         SECTION 4.01. Distributions. Except as otherwise provided in the Act,
all Distributable Cash of the Company shall be distributed to the Member, or
distributions in kind may be made to the Member at such times as the Member
shall determine.

                                    ARTICLE V
                                BOOKS AND RECORDS

         SECTION 5.01. Books and Records. The Member shall keep or cause to be
kept complete and accurate books of account and records that shall reflect all
transactions and other matters and include all documents and other materials
with respect to the Company's business that are usually entered into and
maintained by Persons engaged in similar businesses. All Company financial
statements shall be accurate in all material respects, shall fairly present the
financial position of the Company and the results of its operations and
Distributable Cash and transactions in its reserve accounts, and shall be
prepared in accordance with generally accepted accounting principles, subject,
in the case of quarterly statements, to year-end adjustments. The books of the
Company shall at all times be maintained at the principal office of the Company
or at such other location as the Member decides.

                                   ARTICLE VI
                            MANAGEMENT OF THE COMPANY

         SECTION 6.01. Management. The management of the Company shall be under
the direction of the Member, who may, from time to time, designate one or more
persons to be



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officers of the Company, with such titles as the Member may determine, including
those positions set forth in Section 6.02.

         SECTION 6.02. Officers. Such of the following officers shall be elected
as the Member deems necessary or appropriate: a President, one or more Executive
Vice Presidents, one or more Senior Vice Presidents, one or more Vice
Presidents, a Secretary, a Treasurer, a Controller, one or more Assistant Vice
Presidents, Assistant Secretaries, Assistant Treasurers and Assistant
Controllers, and such other officers with such titles and powers and/or duties
as the Member shall from time to time determine. Officers may be designated for
particular areas of responsibility and simultaneously serve as officers of
subsidiaries or divisions. Any officer so elected may resign at any time upon
written notice to the Member. Such resignation shall take effect at the time
specified therein, and unless otherwise specified therein, no acceptance of such
resignation shall be necessary to make it effective. Any officer may be removed,
with or without cause, by the Member. Any such removal shall be without
prejudice to the contractual rights of such officer, if any, with the Company,
but the election or appointment of any officer shall not of itself create
contractual rights. Any number of offices may be held by the same person. Any
vacancy occurring in any office by death, resignation, removal or otherwise may
be filled for the unexpired portion of the term by the Member.

         (a) President. The President shall have general control of the
business, affairs, operations and property of the Company, subject to the
supervision of the Member. He may sign or execute, in the name of the Company,
all deeds, mortgages, bonds, contracts or other undertakings or instruments,
except in cases where the signing or execution thereof shall have been expressly
delegated by the Member to some other officer or agent of the Company. He shall
have and may exercise such powers and perform such duties as may be provided by
law or as are incident to the office of President of a company (as if the
Company were a Delaware corporation) and such other duties as are assigned from
time to time by the Member.

         (b) Vice Presidents. Each Executive Vice President, Senior Vice
President, Vice President and Assistant Vice President shall have such powers
and perform such duties as may be provided by law or as may from time to time be
assigned to him, either generally or in specific instances, by the Member or the
President. Any Executive Vice President or Senior Vice President may perform any
of the duties or exercise any of the powers of the President at the request of,
or in the absence or disability of, the President or otherwise as occasion may
require in the administration of the business and affairs of the Company.

         Each Executive Vice President, Senior Vice President, Vice President
and Assistant Vice President shall have authority to sign or execute all deeds,
mortgages, bonds, contracts or other instruments on behalf of the Company,
except in cases where the signing or execution thereof shall have been expressly
delegated by the Member to some other officer or agent of the Company.

         (c) Secretary. The Secretary shall keep the records of the Company, in
books provided for that purpose; he shall be custodian of the seal or seals of
the Company; he shall see that the seal is affixed to all documents requiring
same, the execution of which, on behalf of the





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Company, under its seal, is duly authorized, and when said seal is so affixed he
may attest same; and, in general, he shall perform all duties incident to the
office of the secretary of a company (as if the Company were a Delaware
corporation), and such other duties as from time to time may be assigned to him
by the Member or the President or as may be provided by law. Any Assistant
Secretary may perform any of the duties or exercise any of the powers of the
Secretary at the request of, or in the absence or disability of, the Secretary
or otherwise as occasion may require in the administration of the business and
affairs of the Company.

         (d) Treasurer. The Treasurer shall have charge of and be responsible
for all funds, securities, receipts and disbursements of the Company, and shall
deposit, or cause to be deposited, in the name of the Company, all moneys or
other valuable effects in such banks, trust companies or other depositories as
shall, from time to time, be selected by or under authority of the Member; if
required, he shall give a bond for the faithful discharge of his duties, with
such surety or sureties as the Member may determine; he shall keep or cause to
be kept full and accurate records of all receipts and disbursements in books of
the Company and shall render to the Member or the President, whenever requested,
an account of the financial condition of the Company (as if the Company were a
Delaware corporation); and, in general, he shall perform all the duties incident
to the office of treasurer of a company, and such other duties as may be
assigned to him by the Member or the President or as may be provided by law.

         (e) Controller. The Controller shall be the chief accounting officer of
the Company. He shall keep full and accurate accounts of the assets,
liabilities, commitments, receipts, disbursements and other financial
transactions of the Company; shall cause regular audits of the books and records
of account of the Company and supervise the preparation of the Company's
financial statements; and, in general, he shall perform the duties incident to
the office of controller of a company (as if the Company were a Delaware
corporation) and such other duties as may be assigned to him by the Member or
the President or as may be provided by law. If no Controller is elected by the
Member, the Treasurer shall perform the duties of the office of controller.

                                   ARTICLE VII
                         TRANSFERS OF COMPANY INTERESTS

         SECTION 7.01. Transfers. The Member may, directly or indirectly, sell,
assign, transfer, pledge, hypothecate or otherwise dispose of all or any part of
its Interest. Any Person acquiring the Member's Interest shall be admitted to
the Company as a substituted Member with no further action being required on the
part of the Member.

                                  ARTICLE VIII
                           DISSOLUTION AND TERMINATION

         SECTION 8.01. Dissolution. The Company shall be dissolved and its
business wound up upon the decision made at any time by the Member to dissolve
the Company, or upon the occurrence of any event of dissolution under the Act.




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         SECTION 8.02. Liquidation. Upon dissolution, the Company's business
shall be liquidated in an orderly manner. The Member shall wind up the affairs
of the Company pursuant to this Agreement and in accordance with the Act,
including, without limitation, Section 18-804 thereof.

         SECTION 8.03. Distribution of Property. If in the discretion of the
Member it becomes necessary to make a distribution of Company property in kind
in connection with the liquidation of the Company, such property shall be
transferred and conveyed to the Member.

                                   ARTICLE IX
                                 INDEMNIFICATION

         SECTION 9.01. General. Except to the extent expressly prohibited by the
Act, the Company shall indemnify each Person made or threatened to be made a
party to any action or proceeding, whether civil or criminal, by reason of the
fact that such Person or such Person's testator or intestate is or was a member
or officer of the Company, against judgments, fines (including excise taxes
assessed on a Person with respect to an employee benefit plan), penalties,
amounts paid in settlement and reasonable expenses, including attorneys' fees,
actually and necessarily incurred in connection with such action or proceeding,
or any appeal therefrom; provided that no such indemnification shall be made if
a judgment or other final adjudication adverse to such Person establishes that
his conduct did not meet the then applicable minimum statutory standards of
conduct; and provided, further, that no such indemnification shall be required
in connection with any settlement or other non-adjudicated disposition of any
threatened or pending action or proceeding unless the Company has given its
prior consent to such settlement or such other disposition, which consent shall
not be unreasonably withheld.

         SECTION 9.02. Reimbursement. The Company shall advance or promptly
reimburse, upon request, any Person entitled to indemnification hereunder for
all expenses, including attorneys' fees, reasonably incurred in defending any
action or proceeding in advance of the final disposition thereof upon receipt of
an undertaking by or on behalf of such Person (in form and substance
satisfactory to the Company) to repay such amount if such Person is ultimately
found not to be entitled to indemnification or, where indemnification is
granted, to the extent the expenses so advanced or reimbursed exceed the amount
to which such Person is entitled; provided that such Person shall cooperate in
good faith with any request by the Company that common counsel be utilized by
the parties to an action or proceeding who are similarly situated unless to do
so would be inappropriate due to actual or potential conflicts of interest
between or among such parties; and provided, further, that the Company shall
only advance attorneys' fees in respect of legal counsel approved by the
Company, such approval not to be unreasonably withheld.

         SECTION 9.03. Availability. The right to indemnification and
advancement of expenses under this provision is intended to be retroactive and
shall be available with respect to any action or proceeding which relates to
events prior to the effective date of this provision.



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         SECTION 9.04. Indemnification Agreement. The Company is authorized to
enter into agreements with any of its members or officers extending rights to
indemnification and advancement of expenses to such Person to the fullest extent
permitted by applicable law, but the failure to enter into any such agreement
shall not affect or limit the rights of such Person pursuant to this provision.

         SECTION 9.05. Enforceability. In case any provision in this Article IX
shall be determined at any time to be unenforceable in any respect, the other
provisions shall not in any way be affected or impaired thereby, and the
affected provisions shall be given the fullest possible enforcement in the
circumstances, it being the intention of the Company to provide indemnification
and advancement of expenses to its members and officers, acting in such
capacities, to the fullest extent permitted by law.

         SECTION 9.06. No Amendments. No amendment or repeal of this provision
shall apply to or have any effect on the indemnification of, or advancement of
expenses to, the Member or any officer of the Company for, or with respect to,
acts or omissions of such Member or officer occurring prior to such amendment or
repeal.

         SECTION 9.07. Not Exclusive. The foregoing shall not be exclusive of
any other rights to which the Member or any officer may be entitled as a matter
of law and shall not affect any rights to indemnification to which Company
personnel other than the Member or officers may be entitled by contract or
otherwise.

                                    ARTICLE X
                                  MISCELLANEOUS

         SECTION 10.01. Amendments and Consents. This Agreement may be modified
or amended only by the Member.

         SECTION 10.02. Benefits of Agreement. None of the provisions of this
Agreement shall be for the benefit of or enforceable by any creditor of the
Company or the Member.

         SECTION 10.03. Integration. This Agreement constitutes the entire
agreement pertaining to the subject matter hereof and supersedes all prior and
contemporaneous agreements in connection therewith. No covenant, representation
or condition not expressed in this Agreement shall affect, or be effective to
interpret, change or restrict, the express provisions of this Agreement.

         SECTION 10.04. Headings. The titles of Articles and Sections of this
Agreement are for convenience only and shall not be interpreted to limit or
amplify the provisions of this Agreement.

         SECTION 10.05. Counterparts. This Agreement may be executed in multiple
counterparts, each of which shall be deemed an original and all of which, taken
together, shall constitute one and the same instrument, which may be
sufficiently evidenced by one counterpart.



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         SECTION 10.06. Severability. Each provision of this Agreement shall be
considered separable and if for any reason any provision or provisions hereof
are determined to be invalid and contrary to any existing or future law, such
invalidity shall not impair the operation of or affect those portions of this
Agreement, which are valid.

         SECTION 10.07. Applicable Law. This Agreement shall be construed in
accordance with, and governed by, the laws of the State of Delaware, without
regard to its conflict of law principles.

         IN WITNESS WHEREOF, this Limited Liability Company Agreement has been
duly executed by Mesquite Investors, L.L.C., effective as of the 6th day of
January 2003.

                           MESQUITE INVESTORS, L.L.C.

                           By: El Paso Chaparral Management, L.P.
                               Its Manager


                               By:        /s/ Andrew C. Kidd
                                    --------------------------------------------
                                             Andrew C. Kidd
                                           Vice President and
                                        Associate General Counsel





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