EXHIBIT 10.15

                                                                     [MARKETING]
                      FIRST AMENDMENT TO CREDIT AGREEMENT

     THIS FIRST AMENDMENT TO CREDIT AGREEMENT (this "Amendment") dated as of the
18th day of March, 1999, by and among PLAINS MARKETING, L.P. ("Borrower"), ALL
AMERICAN PIPELINE, L.P.("All American"), PLAINS ALL AMERICAN PIPELINE, L.P.
("Plains MLP"), BANKBOSTON, N.A., as Administrative Agent (in such capacity,
"Administrative Agent"), BANCBOSTON ROBERTSON STEPHENS INC., as syndication
agent (in such capacity, "Syndication Agent"), ING BARING FURMAN SELZ LLC, as
documentation agent (in such capacity, "Documentation Agent") and the Lenders a
party hereto.

                             W I T N E S S E T H:

     WHEREAS, Borrower, All American, Plains MLP, Administrative Agent,
Syndication Agent, Documentation Agent and Lenders entered into that certain
Amended and Restated Credit Agreement dated as of November 17, 1998 (as amended,
restated, or supplemented to the date hereof, the "Original Agreement") for the
purposes and consideration therein expressed, pursuant to which Lenders became
obligated to make and made loans to Borrower as therein provided; and

     WHEREAS, Borrower, All American, Plains MLP, Administrative Agent,
Syndication Agent, Documentation Agent and the Lenders a party hereto desire to
amend the Original Agreement for the purposes described herein;

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements contained herein and in the Original Agreement, in consideration
of the loans which may hereafter be made by Lenders to Borrower, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto do hereby agree as follows:

                   ARTICLE I. -- Definitions and References

     (S) 1.1.  Terms Defined in the Original Agreement.  Unless the context
otherwise requires or unless otherwise expressly defined herein, the terms
defined in the Original Agreement shall have the same meanings whenever used in
this Amendment.

     (S) 1.2.  Other Defined Terms.  Unless the context otherwise requires, the
following terms when used in this Amendment shall have the meanings assigned to
them in this (S) 1.2.

     "Amendment" means this First Amendment to Credit Agreement.

     "Amendment Documents" means this Amendment.

     "Credit Agreement" means the Original Agreement as amended hereby.

                           ARTICLE II. -- Amendments

                                      -1-

 
     (S) 2.1.  Definitions.  The definition of "Permitted Investments" set forth
in Section 1.1 of the Original Agreement is hereby amended by replacing "and
(d)" with ", (d)" and adding a new clause (e) at the end thereof, to read as
follows:

     and (e) Investments directly or indirectly by Restricted Persons in
     Unrestricted Subsidiaries in an aggregate amount not to exceed, at any one
     time outstanding, the sum of (i)  $25,000,000, plus (ii) the lesser of
     $40,000,000 or the amount, if any, of Investments of cash in Restricted
     Persons by General Partner or by PAAI LLC (less any amount of such
     Investment returned) at the time in question, provided such Investment of
     cash was made during the period from March 1, 1999 through December 31,
     1999.

     The definition of "Restricted Person" set forth in Section 1.1 of the
Original Agreement is hereby amended in its entirety to read as follows:

     "Restricted Person" means any of Plains MLP and each Subsidiary of Plains
     MLP, including but not limited to Borrower, All American and each
     Subsidiary of Borrower and/or All American, but excluding Unrestricted
     Subsidiaries.

     The definition of "Subsidiary" set forth in Section 1.1 of the Original
Agreement is hereby amended in its entirety to read as follows:

     "Subsidiary" means, with respect to any Person, any corporation,
     association, partnership, limited liability company, joint venture, or
     other business or corporate entity, enterprise or organization which is
     directly or indirectly (through one or more intermediaries) controlled or
     owned more than fifty percent by such Person; provided, however, that no
     Unrestricted Subsidiary shall be deemed a "Subsidiary" of Borrower or
     Plains MLP for purposes of any Loan Document except as provided in Section
     7.17.

     The following definition of "Unrestricted Subsidiary" is hereby added to
Section 1.1 of the Original Agreement immediately following the definition of
"Type":

     "Unrestricted Subsidiary" shall have the meaning given it in Section 7.17.

     (S) 2.2.  Agreements to Deliver Security Documents.  Section 6.14 of the
Original Agreement is hereby amended by adding to such section the following
sentence:

     "In no event shall any Restricted Person be required to grant a Lien in
favor of Administrative Agent for the benefit of Lenders encumbering such
Restricted Person's ownership interest in any Unrestricted Subsidiary."

     (S) 2.3.  Unrestricted Subsidiaries.  Article VII of the Original Agreement
is hereby amended by adding a new Section 7.17 at the end thereof, to read as
follows:

     Section 7.17  Unrestricted Subsidiaries.  Borrower may form one direct
     Subsidiary (such Subsidiary, and each of its Subsidiaries, each an
     "Unrestricted Subsidiary"), which Unrestricted Subsidiaries shall be
     subject to the following:

                                      -2-

 
     (a)  Subject to subsection (d) below, no Unrestricted Subsidiary shall be
          deemed to be a "Restricted Person" or a "Subsidiary" of Borrower or
          Plains MLP for purposes of this Agreement or any other Loan Document,
          and no Unrestricted Subsidiary shall be subject to or included within
          the scope of any provision herein or in any other Loan Document,
          including without limitation any representation, warranty, covenant or
          Event of Default  herein or in any other Loan Document, except as set
          forth in this Section 7.17.

     (b)  No Restricted Person shall guarantee or otherwise become liable in
          respect of any Liability or other obligation of, grant any Lien on any
          of its property to secure any Liability or other obligation of, make
          any Investment in (except as described in clause (e) of the definition
          of  Permitted Investments), or provide any other form of credit
          support to, any Unrestricted Subsidiary, and no Restricted Person
          shall enter into (i) any management contract or agreement with any
          Unrestricted Subsidiary, except upon the prior written consent of
          Majority Lenders, not to be unreasonably withheld, or (ii) any other
          contract or agreement with any Unrestricted Subsidiary, except in the
          course of ordinary business on terms no less favorable to such
          Restricted Person, as applicable, than could be obtained in a
          comparable arm's length transaction with a non-Affiliate of such
          Restricted Person

     (c)  No Unrestricted Subsidiary shall enter into any contract or agreement
          to acquire, or acquire any property, except upon the prior approval of
          Majority Lenders with respect to (i) existing or potential
          environmental or litigation liabilities and (ii) satisfaction as to
          any governmental approval as required which in any event or in the
          aggregate could cause a Material Adverse Change.

     (d)  If any Unrestricted Subsidiary shall fail to consummate one or more
          acquisitions of property as of  December 31, 1999 with a fair market
          value equal to or greater than the amount of Investments made in such
          Unrestricted Subsidiaries by General Partner, PAAI LLC, or Restricted
          Persons pursuant to clause (e) of the definition of Permitted
          Investments as of December 31, 1999, then on and after December 31,
          1999 each Unrestricted Subsidiary shall be deemed to be a "Subsidiary"
          of Borrower for purposes of this Agreement and shall be subject to the
          terms and conditions hereof.

     (e)  Borrower shall at all times maintain the separate existence of each
          Unrestricted Subsidiary.



                  ARTICLE III. -- Conditions of Effectiveness

     (S) 3.1.    Effective Date.  This Amendment shall become effective as of
the date first above written when and only when Administrative Agent shall have
received, at Administrative Agent's office, a counterpart of this Amendment
executed and delivered by Borrower, All American, 

                                      -3-

 
Plains MLP, Administrative Agent, Syndication Agent, Documentation Agent and
Majority Lenders.

                 ARTICLE IV. -- Representations and Warranties

     (S) 4.1.    Representations and Warranties of Plains MLP and Borrower.  In
order to induce Administrative Agent and Lenders to enter into this Amendment,
Plains MLP and Borrower represent and warrant to Administrative Agent and each
Lender that:

          (a) The representations and warranties contained in Article V of the
     Original Agreement, are true and correct at and as of the time of the
     effectiveness hereof, subject to the amendment of certain of the Schedules
     to the Credit Agreement as attached hereto and except to the extent that
     such representation and warranty was made as of a specific date.

          (b) Each Restricted Person is duly authorized to execute and deliver
     this Amendment and the other Amendment Documents to the extent a party
     thereto, and Borrower is and will continue to be duly authorized to borrow
     and perform its obligations under the Credit Agreement.  Each Restricted
     Person has duly taken all corporate action necessary to authorize the
     execution and delivery of this Amendment and the other Amendment Documents,
     to the extent a party thereto, and to authorize the performance of their
     respective obligations thereunder.

          (c) The execution and delivery by each Restricted Person of this
     Amendment and the other Amendment Documents, to the extent a party thereto,
     the performance by each Restricted Person of their respective obligations
     hereunder and thereunder, and the consummation of the transactions
     contemplated hereby and thereby, do not and will not conflict with any
     provision of law, statute, rule or regulation or of the certificate or
     articles of incorporation and bylaws of any Restricted Person, or of any
     material agreement, judgment, license, order or permit applicable to or
     binding upon any Restricted Person, or result in the creation of any lien,
     charge or encumbrance upon any assets or properties of any Restricted
     Person, except in favor of Administrative Agent for the benefit of Lenders.
     Except for those which have been duly obtained, no consent, approval,
     authorization or order of any court or governmental authority or third
     party is required in connection with the execution and delivery by any
     Restricted Person of this Amendment or any other Amendment Document, to the
     extent a party thereto, or to consummate the transactions contemplated
     hereby and thereby.

          (d) When this Amendment and the other Amendment Documents have been
     duly executed and delivered, each of the Loan Documents, as amended by this
     Amendment and the other Amendment Documents, will be a legal and binding
     instrument and agreement of each Restricted Person, to the extent a party
     thereto, enforceable in accordance with its terms, (subject, as to
     enforcement of remedies, to applicable bankruptcy, insolvency and similar
     laws applicable to creditors' rights generally and to general principles of
     equity).

                                      -4-

 
                          ARTICLE V. -- Miscellaneous

     (S) 5.1.    Ratification of Agreements.  The Original Agreement, as hereby
amended, is hereby ratified and confirmed in all respects.  The Loan Documents,
as they may be amended or affected by this Amendment and/or the other Amendment
Documents, are hereby ratified and confirmed in all respects.  Any reference to
the Credit Agreement in any Loan Document shall be deemed to refer to this
Amendment also.  The execution, delivery and effectiveness of this Amendment and
the other Amendment Documents shall not, except as expressly provided herein or
therein, operate as a waiver of any right, power or remedy of Administrative
Agent or any Lender under the Credit Agreement or any other Loan Document nor
constitute a waiver of any provision of the Credit Agreement or any other Loan
Document.

     (S) 5.2.    Ratification of Security Documents.  Restricted Persons,
Administrative Agent and Lenders each acknowledge and agree that any and all
indebtedness, liabilities or obligations arising under or in connection with the
Notes are Obligations and is secured indebtedness under, and is secured by, each
and every Security Document to which any Restricted Person is a party.  Each
Restricted Person hereby re-pledges, re-grants and re-assigns a security
interest in and lien on every asset of the such Restricted Person described as
Collateral in any Security Document.

     (S) 5.3.    Survival of Agreements.  All representations, warranties,
covenants and agreements of the Restricted Persons herein and in the other
Amendment Documents shall survive the execution and delivery of this Amendment
and the other Amendment Documents and the performance hereof and thereof,
including without limitation the making or granting of each Loan, and shall
further survive until all of the Obligations are paid in full.  All statements
and agreements contained in any certificate or instrument delivered by any
Restricted Person hereunder, under the other Amendment Documents or under the
Credit Agreement to Administrative Agent or any Lender shall be deemed to
constitute representations and warranties by, or agreements and covenants of,
such Restricted Person under this Amendment and under the Credit Agreement.

     (S) 5.4.    Loan Documents.  This Amendment and each of the other Amendment
Documents is a Loan Document, and all provisions in the Credit Agreement
pertaining to Loan Documents apply hereto and thereto.

     (S) 5.5.    GOVERNING LAW.  THIS AMENDMENT AND THE OTHER AMENDMENT
DOCUMENTS SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF NEW YORK AND ANY APPLICABLE LAWS OF THE UNITED STATES OF AMERICA IN ALL
RESPECTS, INCLUDING CONSTRUCTION, VALIDITY AND PERFORMANCE.

     (S) 5.6.    Counterparts.  This Amendment and each of the other Amendment
Documents may be separately executed in counterparts and by the different
parties hereto in separate counterparts, each of which when so executed shall be
deemed to constitute one and the same Amendment or Amendment Document, as the
case may be.

                                      -5-

 
     IN WITNESS WHEREOF, this Amendment is executed as of the date first above
written.

                              PLAINS MARKETING, L.P.

                              By: PLAINS ALL AMERICAN INC.,
                                  its general partner

                              By: /s/ Michael R. Patterson
                                 ---------------------------------
                                  Name:  Michael R.  Patterson
                                  Title: Senior Vice President and
                                         General Counsel


                              PLAINS ALL AMERICAN PIPELINE, L.P.

                              By: PLAINS ALL AMERICAN INC.,
                                  its general partner

                              By: /s/ Michael R. Patterson
                                 ---------------------------------
                                  Name:  Michael R.  Patterson
                                  Title: Senior Vice President and
                                         General Counsel


                              ALL AMERICAN PIPELINE, L.P.

                              By: PLAINS ALL AMERICAN INC.,
                                  its general partner

                              By: /s/ Michael R. Patterson
                                 ---------------------------------
                                  Name:  Michael R.  Patterson
                                  Title: Senior Vice President and
                                         General Counsel

                                      -6-

 
                              BANKBOSTON, N.A.,
                              Administrative Agent, LC Issuer and Lender

                              By: /s/ Terrence Ronan
                                 ---------------------------------
                                  Terrence Ronan, Director


                              BANCBOSTON ROBERTSON STEPHENS INC.,
                              Syndication Agent

                              By: /s/ Richard J. Makin
                                 ---------------------------------
                                  Richard J. Makin, Managing Director

                                      -7-

 
                              ING BARING FURMAN SELZ LLC,
                              Documentation Agent

                              By:
                                 ---------------------------------
                                  Name:
                                  Title:


                              ING (U.S.) CAPITAL LLC, Lender

                              By: /s/ Peter Y. Clinton
                                 ---------------------------------
                                  Name:  Peter Y.  Clinton
                                  Title: Senior Vice President

                                      -8-

 
                              BANK OF AMERICA NATIONAL TRUST AND SAVINGS
                              ASSOCIATION, Lender

                              By: /s/ Irene C. Rummel
                                 ---------------------------------
                                  Name:  Irene C.  Rummel
                                  Title: Vice President

                                      -9-

 
                              BANK OF SCOTLAND, Lender

                              By: /s/ Annie Chin Tat
                                 ---------------------------------
                                  Name:  Annie Chin Tat
                                  Title: Senior Vice President

                                      -10-

 
                              COMERICA BANK-TEXAS, Lender

                              By: /s/ Daniel G. Steele
                                 ---------------------------------
                                   Name:  Daniel G. Steele
                                   Title: Senior Vice President

                                      -11-

 
                              DEN NORSKE BANK ASA, Lender

                              By: /s/ J. Morten Kreutz
                                 ---------------------------------
                                  Name:  J. Morten Kreutz
                                  Title: Vice President


                              By: /s/ William V.  Moyer
                                 ---------------------------------
                                  Name:  William V.  Moyer
                                  Title: Senior Vice President

                                      -12-

 
                              FIRST UNION NATIONAL BANK, Lender

                              By: /s/ Robert R. Wetteroff
                                 ---------------------------------
                                  Name:  Robert R. Wetteroff
                                  Title: Senior Vice President

                                      -13-

 
                              HIBERNIA NATIONAL BANK, Lender

                              By: /s/ Tammy Angelety
                                 ---------------------------------
                                  Name:  Tammy Angelety
                                  Title: Assistant Vice President

                                      -14-

 
                              MEESPIERSON CAPITAL CORP., Lender

                              By: /s/ Deirdre M. Sanborn
                                 ---------------------------------
                                  Name:  Deirdre M. Sanborn
                                  Title: Assistant Vice President

                              By: /s/ D. Thomas Abbott
                                 ---------------------------------
                                  Name:  D. Thomas Abbott
                                  Title: Chairman

                                      -15-

 
                              U.S. BANK, NATIONAL ASSOCIATION, Lender

                              By: /s/ Charles S. Searle
                                 ---------------------------------
                                  Name:  Charles S. Searle
                                  Title: Senior Vice President

                                      -16-

 
                              UNION BANK OF CALIFORNIA, N.A., Lender

                              By: /s/ Dustin Gaspari
                                 ---------------------------------
                                  Name:  Dustin Gaspari
                                  Title: Assistant Vice President


                              By: /s/ Carl Stutzman
                                 ---------------------------------
                                  Name:  Carl Stutzman
                                  Title: Senior Vice President and Manager

                                      -17-

 
                              WELLS FARGO BANK (TEXAS),
                              NATIONAL ASSOCIATION, Lender
 

                              By: /s/ Ann M. Rhoads
                                 ---------------------------------
                                  Name:  Ann M.  Rhoads
                                  Title: Vice President

                                      -18-