SECURITIES AND EXCHANGE COMMISSION 
Washington, D.C. 20549 

 
FORM 8-K 
 
CURRENT REPORT 
 
Pursuant to Section 13 or 15(d) of 
the Securities Exchange Act of 1934 
 
Date of Report (Date of earliest event reported) – March 5, 2003 
 
Plains All American Pipeline, L.P. 
(Name of Registrant as specified in its charter) 

DELAWARE	 	0-9808	 	76-0582150	
(State or other jurisdiction of incorporation or organization)	 	(Commission File Number)	 	(I.R.S. Employer
Identification No.)	
 
333 Clay Street, Suite 1600 
Houston, Texas 77002 
(713) 646-4100 
(Address, including zip code, and telephone number, 
including area code, of Registrant’s principal executive offices) 
 
N/A 
(Former name or former address, if changed since last report.) 

 

Item 5.    Other Events 
 
On March 5, 2003, Plains All American Pipeline, L.P. (the “Partnership”) entered into an underwriting agreement with Goldman, Sachs & Co. and A. G. Edwards & Sons, Inc. in connection with the sale by the Partnership of 2,300,000 common units of the Partnership. The underwriters were also granted an option to purchase up to an additional 345,000 Common Units. 
 
Item 7.    Financial Statements and Exhibits 
 
(c)    Exhibits 
 
1.1    Underwriting Agreement dated March 5, 2003 by and among Plains All American Pipeline, L.P., Plains AAP, L.P., Plains All American GP LLC, Plains Marketing, L.P., All American Pipeline, L.P., Plains Marketing GP Inc., Goldman, Sachs & Co. and A. G. Edwards & Sons, Inc. 
 
5.1    Legal	 	opinion of Vinson & Elkins LLP 	
 
99.1  Press Release dated March 6, 2003. 
 
SIGNATURES 
 
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. 
 
PLAINS ALL AMERICAN PIPELINE, L.P. 
 
Date: March 6, 2003                                                                                 By: Plains AAP, L. P., its general partner 
 
By:    /s/    Phil Kramer 

Name:  Phil Kramer 
Title:    Executive Vice President and Chief 
             Financial Officer 

                                                                     EXHIBIT 1.1

                       PLAINS ALL AMERICAN PIPELINE, L.P.

                             2,300,000 Common Units

                     Representing Limited Partner Interests

                             UNDERWRITING AGREEMENT

                                                                   March 5, 2003

GOLDMAN, SACHS & CO.
A.G. EDWARDS & SONS, INC.

c/o GOLDMAN, SACHS & CO.
      85 Broad Street
      New York, New York  10004

Dear Sirs:

          Plains All American Pipeline, L.P., a Delaware limited partnership
(the "Partnership"), proposes to issue and sell an aggregate of 2,300,000 common
units (the "Firm Units") representing limited partner interests in the
Partnership (the "Common Units") to the several underwriters named in Schedule I
hereto (the "Underwriters"), upon the terms and conditions set forth in Section
2 hereof. The Partnership also proposes to sell to the Underwriters, upon the
terms and conditions set forth in Section 2 hereof, up to an additional 345,000
Common Units (the "Additional Units"). The Firm Units and the Additional Units
are hereinafter collectively referred to as the "Units."

          Plains AAP, L.P., a Delaware limited partnership (the "General
Partner"), is the general partner of the Partnership. Plains All American GP
LLC, a Delaware limited liability company ("GP LLC"), is the general partner of
the General Partner. The Partnership owns 100% of the issued and outstanding
shares of Plains Marketing GP Inc., a Delaware corporation ("GP Inc.") and the
general partner of each of Plains Marketing, L.P., a Delaware limited
partnership ("Plains Marketing"), and All American Pipeline, L.P., a Texas
limited partnership ("All American"). Plains Marketing owns a 100% membership
interest in Plains Marketing Canada LLC, a Delaware limited liability company
("PMC LLC"), and a 99.99% limited partner interest in Plains Marketing Canada,
L.P., an Alberta limited partnership ("PMC LP"). PMC LLC owns 100% of the issued
and outstanding share capital of PMC (Nova Scotia) Company, a Nova Scotia
unlimited liability company ("PMC NS"). PMC NS owns a 0.01% general partner
interest in PMC LP. All American owns a 100% membership interest in Basin
Holdings GP LLC, a Delaware limited liability company ("Basin LLC"), and a
99.999% limited partner interest in Basin Pipeline Holdings, LP, a Delaware
limited partnership ("Basin LP"). Basin LLC owns a 0.001% general partner
interest in Basin LP. GP Inc., Plains Marketing, All American, PMC LLC, PMC LP,
PMC NS, Basin LLC and Basin LP are collectively referred to herein as the
"Subsidiaries." The Partnership, the General Partner, GP LLC, GP Inc., Plains
Marketing and All American are collectively referred to herein as the "Plains
Parties."

                                        1

          The Plains Parties wish to confirm as follows their agreement with you
in connection with the several purchases of the Units by the Underwriters.

          1.   Registration Statement and Prospectus. The Partnership has
prepared and filed with the Securities and Exchange Commission (the
"Commission") in accordance with the provisions of the Securities Act of 1933,
as amended, and the rules and regulations of the Commission thereunder
(collectively, the "Act"), a registration statement on Form S-3 under the Act
(Commission File No. 333-68446) (the "registration statement"), including a
prospectus subject to completion relating to the Units. Such registration
statement has been declared effective by the Commission. The term "Registration
Statement" as used in this Agreement means the registration statement (including
all financial schedules and exhibits), as supplemented or amended prior to the
execution of this Agreement. If it is contemplated, at the time this Agreement
is executed, that a post-effective amendment to the registration statement will
be filed and must be declared effective before the offering of the Units may
commence, the term "Registration Statement" as used in this Agreement means the
registration statement as amended by said post-effective amendment. If it is
contemplated, at the time this Agreement is executed, that a registration
statement or a post-effective amendment will be filed pursuant to Rule 462(b) or
Rule 462(d) under the Act before the offering of the Units may commence, the
term "Registration Statement" as used in this Agreement includes such
registration statement. The term "Basic Prospectus" as used in this Agreement
means the prospectus in the form included in the Registration Statement at the
time that the Registration Statement was declared effective or in the form in
which it has been most recently filed with the Commission on or prior to the
date of this Agreement. "Final Prospectus" shall mean the prospectus supplement
relating to the Units and the offering thereof that is first filed pursuant to
Rule 424(b) under the Act ("Rule 424(b)") after the date and time this Agreement
is executed and delivered by the parties hereto, together with the Basic
Prospectus.

          All references in this Agreement to financial statements and schedules
and other information which is "contained," "included" or "stated" in the
Registration Statement, the Basic Prospectus or the Final Prospectus (or other
references of like import) shall be deemed to mean and include all such
financial statements and schedules and other information which is incorporated
by reference in the Registration Statement, the Basic Prospectus or the Final
Prospectus, as the case may be; any reference in this Agreement to the
Registration Statement, the Basic Prospectus or the Final Prospectus shall be
deemed to refer to and include the documents incorporated by reference therein
pursuant to Item 12 of Form S-3 under the Act, as of the date of the
Registration Statement, the Basic Prospectus or the Final Prospectus, as the
case may be; and any reference to any amendment or supplement to the
Registration Statement, the Basic Prospectus or the Final Prospectus shall be
deemed to refer to and include any documents filed after such date under the
Securities Exchange Act of 1934, as amended, and the rules and regulations of
the Commission thereunder (the "Exchange Act") which, upon filing, are
incorporated by reference therein, as required by paragraph (b) of Item 12 of
Form S-3. As used herein, the term "Incorporated Documents" means the documents
which at the time are incorporated by reference in the Registration Statement,
the Basic Prospectus or the Final Prospectus or any amendment or supplement
thereto.

          2.   Purchase and Sale. (a) Subject to the terms and conditions and in
reliance upon the representations and warranties herein set forth, the
Partnership agrees to sell to each

                                        2

Underwriter, and each Underwriter agrees, severally and not jointly, to purchase
from the Partnership, at a purchase price of $23.746 per Unit, the amount of the
Firm Units set forth opposite such Underwriter's name in Schedule I hereto.

          (b)  Subject to the terms and conditions and in reliance upon the
representations and warranties herein set forth, the Partnership hereby grants
an option to the several Underwriters to purchase, severally and not jointly, up
to 345,000 Additional Units at the same purchase price per Unit as the
Underwriters shall pay for the Firm Units. Said option may be exercised in whole
or in part at any time and from time to time on or before the 30th day after the
date of the Final Prospectus upon written or telegraphic notice by the
Underwriters to the Partnership setting forth the number of Additional Units as
to which the several Underwriters are exercising the option and the settlement
date. The number of Additional Units to be purchased by each Underwriter shall
be the same percentage of the total number of shares of the Additional Units to
be purchased by the several Underwriters as such Underwriter is purchasing of
the Firm Units, subject to such adjustments as you in your absolute discretion
shall make to eliminate any fractional shares.

          3.   Delivery and Payment. Delivery of and payment for the Firm Units
and the Additional Units (if the option provided for in Section 2(b) hereof
shall have been exercised on or before the third business day prior to the
Closing Date) shall be made at 10:00 AM, New York City time, on March 11, 2003,
or at such time on such later date not more than three business days after the
foregoing date as the Underwriters shall designate, which date and time may be
postponed by agreement between the Underwriters and the Partnership (such date
and time of delivery and payment for the Units being herein called the "Closing
Date"). Delivery of the Units shall be made to the Underwriters for the
respective accounts of the several Underwriters against payment by the several
Underwriters of the purchase price thereof to or upon the order of the
Partnership by wire transfer payable in same-day funds to an account specified
by the Partnership. Delivery of the Firm Units and the Additional Units shall be
made through the facilities of The Depository Trust Company unless the
Underwriters shall otherwise instruct.

          If the option provided for in Section 2(b) hereof is exercised after
the third business day prior to the Closing Date, the Partnership will deliver
the Additional Units (at the expense of the Partnership) to Goldman, Sachs &
Co., 85 Broad Street, New York, New York 10004, on the date (an "Option Closing
Date") specified by the Underwriters (which shall be within three business days
after each exercise of said option), for the respective accounts of the several
Underwriters, against payment by the several Underwriters of the purchase price
thereof to or upon the order of the Partnership by wire transfer payable in
same-day funds to an account specified by the Partnership. If settlement for the
Additional Units occurs after the Closing Date, the Partnership will deliver to
the Underwriters on the settlement date for the Additional Units, and the
obligation of the Underwriters to purchase the Additional Units shall be
conditioned upon receipt of, supplemental opinions, certificates and letters
confirming as of such date the opinions, certificates and letters delivered on
the Closing Date pursuant to Section 8 hereof.

          4.   Offering by Underwriters. It is understood that the several
Underwriters propose to offer the Units for sale to the public as set forth in
the Final Prospectus.

                                        3

          5.   Agreements of the Plains Parties. Each of the Plains Parties,
jointly and severally, agrees with the Underwriters as follows:

          (a)  If, at the time this Agreement is executed and delivered, it is
necessary for the Registration Statement or a post-effective amendment thereto
to be declared effective before the offering of the Units may commence, the
Partnership, the General Partner and GP LLC will endeavor to cause the
Registration Statement or such post-effective amendment to become effective as
soon as possible and will advise you promptly and, if requested by you, will
confirm such advice in writing when the Registration Statement or such
post-effective amendment has become effective.

          (b)  The Partnership will advise you promptly and, if requested by
you, will confirm such advice in writing: (i) of any request by the Commission
for amendment of or a supplement to the Registration Statement, the Basic
Prospectus or the Final Prospectus or for additional information; (ii) of the
issuance by the Commission of any stop order suspending the effectiveness of the
Registration Statement or of the suspension of qualification of the Units for
offering or sale in any jurisdiction or the initiation of any proceeding for
such purpose; and (iii) within the period of time referred to in paragraph (e)
below, of any change in the condition (financial or other), business, prospects,
properties, net worth or results of operations of the Plains Parties, taken as a
whole, or of the happening of any event which makes any statement of a material
fact made in the Registration Statement or the Final Prospectus (as then amended
or supplemented) untrue or which requires the making of any additions to or
changes in the Registration Statement or the Final Prospectus (as then amended
or supplemented) in order to state a material fact required by the Act or the
regulations thereunder to be stated therein or necessary in order to make the
statements therein not misleading, or of the necessity to amend or supplement
the Final Prospectus (as then amended or supplemented) to comply with the Act or
any other applicable law. If at any time the Commission shall issue any stop
order suspending the effectiveness of the Registration Statement, the
Partnership, the General Partner and GP LLC will make every commercially
reasonable effort to obtain the withdrawal of such order at the earliest
possible time.

          (c)  The Partnership will furnish to you, without charge, (i) one copy
of the manually signed copy of the registration statement corresponding to the
EDGAR version filed with the Commission and of each amendment thereto, including
financial statements and all exhibits to the registration statement, (ii) such
number of conformed copies of the registration statement as originally filed and
of each amendment thereto, but without exhibits, as you or your counsel may
reasonably request, (iii) such number of copies of the Incorporated Documents,
without exhibits, as you may request, and (iv) such number of copies of the
exhibits to the Incorporated Documents as you may request.

          (d)  The Partnership will not

               (i)  file any amendment to the Registration Statement or make any
     amendment or supplement to the Final Prospectus or

                                        4

               (ii)  within the time period specified in the first sentence of
     (e) below, file any information, documents or reports which, upon filing
     become Incorporated Documents,

of which you shall not previously have been advised or to which you or your
counsel shall reasonably object in writing after being so advised unless the
Partnership shall have determined based on the advice of counsel that such
amendment or supplement is required by law.

          (e)  As soon after the execution and delivery of this Agreement as
possible and thereafter from time to time for such period as in the opinion of
counsel for the Underwriters a prospectus is required by the Act to be delivered
in connection with sales by any Underwriter or dealer, the Partnership will
expeditiously deliver to each Underwriter and each dealer that you may specify,
without charge, as many copies of the Final Prospectus (and of any amendment or
supplement thereto) as you may reasonably request. At any time after nine months
after the time of issuance of the Final Prospectus, upon request, but at your
expense, the Partnership will deliver as many copies of an amended or
supplemented Final Prospectus complying with Section 10(a)(3) of the Act as you
may reasonably request, provided that a prospectus is required by the Act to be
delivered in connection with sales of Units by any Underwriter or dealer. The
Partnership consents to the use of the Final Prospectus (and of any amendment or
supplement thereto) in accordance with the provisions of the Act and with the
securities or Blue Sky laws of the jurisdictions in which the Units are offered
by the Underwriters and by all dealers to whom Units may be sold, both in
connection with the offering and sale of the Units and for such period of time
thereafter as the Final Prospectus is required by the Act to be delivered in
connection with sales by any Underwriter or dealer. If during such period of
time any event shall occur that in the judgment of the Partnership or in the
opinion of counsel for the Underwriters and the Partnership is required to be
set forth in the Final Prospectus (as then amended or supplemented) or should be
set forth therein in order to make the statements therein, in the light of the
circumstances under which they were made, not misleading, or if it is necessary
to supplement or amend the Final Prospectus (or to file under the Exchange Act
any document which, upon filing, becomes an Incorporated Document) to comply
with the Act or any other law, the Partnership will forthwith prepare and,
subject to the provisions of paragraph (d) above, file with the Commission an
appropriate supplement or amendment thereto (or to such document), and will
expeditiously furnish to the Underwriters and dealers a reasonable number of
copies thereof; provided that, if any such event necessitating a supplement or
amendment to the Final Prospectus occurs at any time after nine months after the
time of issuance of the Final Prospectus, such supplement or amendment shall be
prepared at your expense. In the event that the Partnership and you agree that
the Final Prospectus should be amended or supplemented, the Partnership, if
requested by you, will promptly issue a press release announcing or disclosing
the matters to be covered by the proposed amendment or supplement unless the
Partnership shall have determined, based on the advice of counsel, that the
issuance of such press release would not be required by law.

          (f)  The Partnership, the General Partner and GP LLC will cooperate
with you and with counsel for the Underwriters in connection with the
registration or qualification of the Units for offering and sale by the
Underwriters and by dealers under the securities or Blue Sky laws of such
jurisdictions as you may reasonably designate and will file such consents to
service of process or other documents reasonably necessary or appropriate in
order to effect such

                                        5

registration or qualification; provided that in no event shall any Plains Party
be obligated to qualify to do business in any jurisdiction where it is not now
so qualified or to take any action which would subject it to service of process
in suits, other than those arising out of the offering or sale of the Units, in
any jurisdiction where it is not now so subject.

         (g)  The Partnership will make generally available to its security
holders a consolidated earnings statement, which need not be audited, covering a
twelve-month period commencing after the effective date of the Registration
Statement and ending not later than 15 months thereafter, as soon as practicable
after the end of such period, which consolidated earnings statement shall
satisfy the provisions of Section 11(a) of the Act.

         (h)  During the period of two years hereafter, the Partnership will
furnish or make available to you (i) as soon as publicly available, a copy of
each report of the Partnership mailed to unitholders or filed with the
Commission or the principal national securities exchange or automated quotation
system upon which the Units may be listed, and (ii) from time to time such other
information concerning the Partnership as you may reasonably request.

         (i)  If this Agreement shall terminate or shall be terminated after
execution pursuant to any provisions hereof (otherwise than pursuant to the
second paragraph of Section 10 hereof or Section 11 hereof) or if this Agreement
shall be terminated by the Underwriters because of any failure or refusal on the
part of any of the Plains Parties to comply with the terms or fulfill any of the
conditions of this Agreement, the Plains Parties, jointly and severally, agree
to reimburse the Underwriters for all reasonable out-of-pocket expenses
(including reasonable fees and expenses of counsel for the Underwriters)
incurred by you in connection herewith.

         (j)  The Partnership and the Subsidiaries will apply the net proceeds
from the sale of the Units in accordance with the description set forth under
the caption "Use of Proceeds" in the Final Prospectus.

         (k)  The Partnership will timely file the Final Prospectus pursuant to
Rule 424(b) under the Act and will advise you of the time and manner of such
filing.

         (l)  Except as provided in this Agreement, the Plains Parties will not
(i) offer, sell, contract to sell or otherwise dispose of or hedge any Common
Units or subordinated limited partnership interests of the Partnership (the
"Subordinated Units"), any securities that are convertible into, or exercisable
or exchangeable for, or that represent the right to receive, Common Units or
Subordinated Units or any securities that are senior to or pari passu with
Common Units, or (ii) grant any options or warrants to purchase Common Units or
Subordinated Units (other than the grant of Unit Options or Restricted Units
pursuant to the Plains All American GP LLC 1998 Long-Term Incentive Plan or the
Performance Option Plan of Plains AAP, L.P. and Plains All American GP LLC), for
a period of 90 days after the date of the Final Prospectus without the prior
written consent of Goldman, Sachs & Co., except for the issuance of Units
pursuant to this Agreement and the issuance of Common Units pursuant to Section
5.7(b) of the Third Amended and Restated Agreement of Limited Partnership of the
Partnership (as the same may be amended or restated prior to the Closing Date,
the "Partnership Agreement").

                                       6

         (m)  Except as stated in this Agreement and the Final Prospectus, the
Plains Parties have not taken, and will not take, directly or indirectly, any
action designed to or that might reasonably be expected to cause or result in
stabilization or manipulation of the price of the Common Units to facilitate the
sale or resale of the Units.

         (n)  Each of the Plains Parties will take such steps as shall be
necessary to ensure that none of them shall become an "investment company"
within the meaning of such term under the Investment Company Act of 1940, as
amended, and the rules and regulations of the Commission thereunder.

         (o)  Upon the issuance of the Units by the Partnership, the General
Partner shall make the additional capital contributions to the Partnership as
required by Section 5.2(b) of the Partnership Agreement.

         (p)  The Partnership, during the period when the Final Prospectus is
required to be delivered under the Act, will file all documents required to be
filed with the Commission pursuant to the Exchange Act within the time periods
required by the Exchange Act.

         6.   Representations and Warranties of the Plains Parties. The Plains
Parties, jointly and severally, represent and warrant to the Underwriters that:

         (a)  The Partnership and the offering of the Units contemplated by this
Agreement meet the requirements for using Form S-3 under the Act. The Basic
Prospectus included as part of the Registration Statement as originally filed or
as part of any amendment or supplement thereto at the date of filing thereof
with the Commission, complied in all material respects with the requirements of
the Act and did not contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary in order to
make the statements therein, in the light of the circumstances under which they
were made, not misleading. The Commission has not issued any order preventing or
suspending the use of the Basic Prospectus. The Registration Statement in the
form in which it became or becomes effective and also in such form as it may be
when any post-effective amendment thereto shall become effective and the Final
Prospectus and any supplement or amendment thereto when filed with the
Commission under Rule 424(b) under the Act complied or will comply in all
material respects with the provisions of the Act and did not or will not at any
such times contain an untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary to make the statements
therein not misleading. Each of the statements made by the Partnership in such
documents within the coverage of Rule 175(b) of the rules and regulations under
the Act, including (but not limited to) any statements with respect to future
available cash or future cash distributions of the Partnership or the
anticipated ratio of taxable income to distributions was made or will be made
with a reasonable basis and in good faith. Notwithstanding the foregoing, no
representation or warranty is made as to statements in or omissions from the
Registration Statement or the Final Prospectus made in reliance upon and in
conformity with information furnished to the Partnership in writing by or on
behalf of any Underwriter through you expressly for use therein.

         (b)  The Incorporated Documents heretofore filed, when they were filed
(or, if any amendment with respect to any such document was filed, when such
amendment was filed),

                                       7

conformed in all material respects with the requirements of the Exchange Act;
any further Incorporated Documents so filed will, when they are filed, conform
in all material respects with the requirements of the Exchange Act; no such
document when it was filed (or, if an amendment with respect to any such
document was filed, when such amendment was filed), contained an untrue
statement of a material fact or omitted to state a material fact required to be
stated therein or necessary in order to make the statements therein not
misleading; and no such further document, when it is filed, will contain an
untrue statement of a material fact or will omit to state a material fact
required to be stated therein or necessary in order to make the statements
therein not misleading.

         (c)  Each of the Partnership, the General Partner, Plains Marketing and
Basin LP has been duly formed and is validly existing in good standing as a
limited partnership under the Delaware Revised Uniform Limited Partnership Act
(the "Delaware LP Act") with full partnership power and authority to own or
lease its properties and to conduct its business and, in the case of the General
Partner, to act as the general partner of the Partnership, in each case in all
material respects as described in the Registration Statement and the Final
Prospectus. Each of the Partnership, the General Partner, Plains Marketing and
Basin LP is duly registered or qualified as a foreign limited partnership for
the transaction of business under the laws of each jurisdiction in which the
character of the business conducted by it or the nature or location of the
properties owned or leased by it makes such registration or qualification
necessary, except where the failure so to register or qualify would not (i) have
a material adverse effect on the condition (financial or other), business,
prospects, properties, net worth or results of operations of the Partnership and
the Subsidiaries, taken as a whole, or (ii) subject the limited partners of the
Partnership to any material liability or disability.

         (d)  All American has been duly formed and is validly existing in good
standing as a limited partnership under the Texas Revised Uniform Limited
Partnership Act (the "Texas LP Act") with full partnership power and authority
to own or lease its properties and to conduct its business, in each case in all
material respects as described in the Registration Statement and the Final
Prospectus. All American is duly registered or qualified as a foreign limited
partnership for the transaction of business under the laws of each jurisdiction
in which the character of the business conducted by it or the nature or location
of the properties owned or leased by it makes such registration or qualification
necessary, except where the failure so to register or qualify would not (i) have
a material adverse effect on the condition (financial or other), business,
prospects, properties, net worth or results of operations of the Partnership and
the Subsidiaries, taken as a whole or (ii) subject the limited partners of the
Partnership to any material liability or disability.

         (e)  GP Inc. has been duly incorporated and is validly existing in good
standing under the laws of the State of Delaware with full corporate power and
authority to own or lease its properties, to conduct its business and to act as
general partner of Plains Marketing and All American, in each case in all
material respects as described in the Registration Statement and the Final
Prospectus. GP Inc. is duly registered or qualified as a foreign corporation for
the transaction of business under the laws of each jurisdiction in which the
character of the business conducted by it or the nature or location of the
properties owned or leased by it makes such registration or qualification
necessary, except where the failure so to register or qualify would not (i) have
a material adverse effect on the condition (financial or other), business,
prospects,

                                       8

properties, net worth or results of operations of the Partnership and the
Subsidiaries, taken as a whole, or the General Partner or (ii) subject the
limited partners of the Partnership to any material liability or disability.

         (f)  Each of GP LLC, PMC LLC and Basin LLC has been duly formed and is
validly existing in good standing as a limited liability company under the
Delaware Limited Liability Company Act (the "Delaware LLC Act") with full
limited liability company power and authority to own or lease its properties and
to conduct its business and, in the cases of GP LLC and Basin LLC, to act as the
general partner of the General Partner and Basin LP, respectively, in each case
in all material respects as described in the Registration Statement and the
Final Prospectus. Each of GP LLC, PMC LLC and Basin LLC is duly registered or
qualified as a foreign limited liability company for the transaction of business
under the laws of each jurisdiction in which the character of the business
conducted by it or the nature or location of the properties owned or leased by
it makes such registration or qualification necessary, except where the failure
so to register or qualify would not (i) have a material adverse effect on the
condition (financial or other), business, prospects, properties, net worth or
results of operations of the Partnership and the Subsidiaries, taken as a whole
or (ii) subject the limited partners of the Partnership to any material
liability or disability.

         (g)  PMC NS has been duly formed and is validly existing in good
standing as an unlimited liability company under the laws of Nova Scotia with
full unlimited liability company power and authority to own or lease its
properties, to conduct its business and to act as general partner of PMC LP. PMC
NS is duly registered extra-provincially for the transaction of business under
the laws of each jurisdiction in which the character of the business conducted
by it or the nature or location of the properties owned or leased by it makes
such registration or qualification necessary, except where the failure so to
register or qualify would not (i) have a material adverse effect on the
condition (financial or other), business, prospects, properties, net worth or
results of operations of the Partnership and the Subsidiaries, taken as a whole
or (ii) subject the limited partners of the Partnership to any material
liability or disability.

         (h)  PMC LP has been duly formed and is validly existing in good
standing as a limited partnership under the laws of Alberta with full
partnership power and authority to own or lease its properties and to conduct
its business, in each case in all material respects as described in the
Registration Statement and the Final Prospectus. PMC LP is duly registered for
the transaction of business under the laws of each jurisdiction in which the
character of the business conducted by it or the nature or location of the
properties owned or leased by it makes such registration or qualification
necessary, except where the failure so to register or qualify would not (i) have
a material adverse effect on the condition (financial or other), business,
prospects, properties, net worth or results of operations of the Partnership and
the Subsidiaries, taken as a whole, or (ii) subject the limited partners of the
Partnership to any material liability or disability.

         (i)  GP LLC is the sole general partner of the General Partner, with a
1.0% general partner interest in the General Partner; such general partner
interest has been duly authorized and validly issued in accordance with the
Amended and Restated Agreement of Limited Partnership of the General Partner (as
the same may be amended or restated prior to the Closing Date, the "General
Partner Partnership Agreement"); and GP LLC owns such general

                                       9

partner interest free and clear of all liens, encumbrances, security interests,
equities, charges or claims.

         (j)  As of the date hereof, the issued and outstanding limited partner
interests of the Partnership consist of 38,240,939 Common Units, 1,307,190 Class
B Common Units representing limited partner interests in the Partnership (the
"Class B Units"), 10,029,619 Subordinated Units and the Incentive Distribution
Rights (as such capitalized term is defined in the Partnership Agreement). All
outstanding Common Units, Class B Units, Subordinated Units and Incentive
Distribution Rights and the limited partner interests represented thereby have
been duly authorized and validly issued in accordance with the Partnership
Agreement and are fully paid (to the extent required under the Partnership
Agreement) and nonassessable (except as such nonassessability may be affected by
matters described under the caption "The Partnership Agreement--Limited
Liability" in the Partnership's Registration Statement on Form S-1 (No.
333-64107) which is incorporated by reference into the Partnership's
Registration Statement on Form 8-A/A (File No. 001-14569) (the "Form 8-A")). The
authorized limited partner interests of the Partnership conform as to legal
matters to the descriptions thereof contained in the Final Prospectus.

         (k)  The General Partner is the sole general partner of the
Partnership, with a 2.0% general partner interest in the Partnership; such
general partner interest has been duly authorized and validly issued in
accordance with the Partnership Agreement; the General Partner owns 450,000
Subordinated Units and all of the Incentive Distribution Rights; and the General
Partner owns such general partner interest, Subordinated Units and Incentive
Distribution Rights free and clear of all liens, encumbrances, security
interests, equities, charges or claims, except, with respect to the Subordinated
Units, (x) the economic interests attributable to distributions on such units as
allocated in accordance with the General Partner Partnership Agreement and (y)
the interest in such units held by grantees under the Plains 2001 Performance
Option Plan.

         (l)  At the Closing Date, there will be issued to the Underwriters the
Firm Units (assuming no purchase by the Underwriters of Additional Units); at
the Closing Date or at any Option Closing Date, as the case may be, the Firm
Units or the Additional Units, as the case may be, and the limited partner
interests represented thereby will be duly authorized by the Partnership
Agreement and, when issued and delivered to the Underwriters against payment
therefor in accordance with the terms hereof, will be validly issued, fully paid
(to the extent required under the Partnership Agreement) and nonassessable
(except as such nonassessability may be affected by matters described in the
Form 8-A).

         (m)  The Partnership owns 100% of the issued and outstanding capital
stock of GP Inc.; such capital stock has been duly authorized and validly issued
and is fully paid and nonassessable; and the Partnership owns such capital stock
free and clear of all liens, encumbrances, security interests, equities, charges
or claims, except as provided in the Second Amended and Restated Credit
Agreement [Revolving Credit Facility] dated as of July 2, 2002 among All
American, Plains Marketing, PMC NS, PMC LP and the Partnership and the lenders
named therein (as amended and in effect as of the Closing Date, the "Plains Bank
Credit Agreement") and the Second Amended and Restated Credit Agreement [Letter
of Credit and Hedged Inventory Facility] dated as of July 2, 2002 among All
American, Plains Marketing and

                                       10

the Partnership and the lenders named therein (as amended and in effect as of
the Closing Date, the "Plains Letter of Credit Facility").

          (n) GP Inc. is the sole general partner of Plains Marketing with a
..001% general partner interest in Plains Marketing; such general partner
interest has been duly authorized and validly issued in accordance with the
Second Amended and Restated Agreement of Limited Partnership of Plains Marketing
(as the same may be amended or restated prior to the Closing Date, the "Plains
Marketing Partnership Agreement"); and GP Inc. owns such general partner
interest free and clear of all liens, encumbrances, security interests,
equities, charges or claims, except as provided in the Plains Bank Credit
Agreement and the Plains Letter of Credit Facility.

          (o) GP Inc. is the sole general partner of All American with a .001%
general partner interest in All American; such general partner interest has been
duly authorized and validly issued in accordance with the Second Amended and
Restated Agreement of Limited Partnership of All American (as the same may be
amended or restated prior to the Closing Date, the "All American Partnership
Agreement"); and GP Inc. owns such general partner interest free and clear of
all liens, encumbrances, security interests, equities, charges or claims, except
as provided in the Plains Bank Credit Facility and the Plains Letter of Credit
Facility.

          (p) The Partnership is the sole limited partner of Plains Marketing
with a 99.999% limited partner interest in Plains Marketing; such limited
partner interest has been duly authorized and validly issued in accordance with
the Plains Marketing Partnership Agreement and is fully paid (to the extent
required under the Plains Marketing Partnership Agreement) and nonassessable
(except as such nonassessability may be affected by Section 17-607 of the
Delaware LP Act); and the Partnership owns such limited partner interest free
and clear of all liens, encumbrances, security interests, equities, charges or
claims, except as provided in the Plains Bank Credit Agreement and the Plains
Letter of Credit Facility.

          (q) Plains Marketing is the sole limited partner of All American with
a 99.999% limited partner interest in All American; such limited partner
interest has been duly authorized and validly issued in accordance with the All
American Partnership Agreement and is fully paid (to the extent required under
the All American Partnership Agreement) and nonassessable (except as such
nonassessability may be affected by Section 6.07 of the Texas LP Act); and
Plains Marketing owns such limited partner interest free and clear of all liens,
encumbrances, security interests, equities, charges or claims, except as
provided in the Plains Bank Credit Agreement and the Plains Letter of Credit
Facility.

          (r) All American owns a 100% member interest in Basin LLC; such member
interest has been duly authorized and validly issued in accordance with the
Limited Liability Company Agreement of Basin LLC (as the same may be amended or
restated prior to the Closing Date, the "Basin LLC Agreement") and is fully paid
(to the extent required under the Basin LLC Agreement) and nonassessable (except
as such nonassessability may be affected by Section 18-607 of the Delaware LLC
Act); and All American owns such member interest free and clear of all liens,
encumbrances, security interests, equities, charges or claims, except as
provided in the Plains Bank Credit Agreement and the Plains Letter of Credit
Facility.

                                       11

          (s) All American is the sole limited partner of Basin LP with a
99.999% limited partner interest in Basin LP; such limited partner interest has
been duly authorized and validly issued in accordance with the Agreement of
Limited Partnership of Basin LP (as the same may be amended or restated prior to
the Closing Date, the "Basin LP Partnership Agreement") and is fully paid (to
the extent required under the Basin LP Partnership Agreement) and nonassessable
(except as such nonassessability may be affected by Section 17-607 of the
Delaware LP Act); and All American owns such limited partner interest free and
clear of all liens, encumbrances, security interests, equities, charges or
claims, except as provided in the Plains Bank Credit Agreement and the Plains
Letter of Credit Facility.

          (t) Basin LLC is the sole general partner of Basin LP with a 0.001%
general partner interest in Basin LP; such general partner interest has been
duly authorized and validly issued in accordance with the Basin LP Partnership
Agreement; and Basin LLC owns such general partner interest free and clear of
all liens, encumbrances, security interests, equities, charges or claims, except
as provided in the Plains Bank Credit Agreement and the Plains Letter of Credit
Facility.

          (u) Plains Marketing owns a 100% member interest in PMC LLC; such
member interest has been duly authorized and validly issued in accordance with
the Limited Liability Company Agreement of PMC LLC (as the same may be amended
or restated prior to the Closing Date, the "PMC LLC Agreement") and is fully
paid (to the extent required under the PMC LLC Agreement) and nonassessable
(except as such nonassessability may be affected by Section 18-607 of the
Delaware LLC Act); and Plains Marketing owns such member interest free and clear
of all liens, encumbrances, security interests, equities, charges or claims,
except as provided in the Plains Bank Credit Agreement and the Plains Letter of
Credit Facility.

          (v) Plains Marketing is the sole limited partner of PMC LP with a
99.99% interest in PMC LP; such limited partner interest has been duly
authorized and validly issued in accordance with the Agreement of Limited
Partnership of PMC LP (as the same may be amended or restated prior to the
Closing Date, the "PMC LP Partnership Agreement" and, together with the
Partnership Agreement, the General Partner Partnership Agreement, the Plains
Marketing Partnership Agreement, the All American Partnership Agreement and the
Basin LP Partnership Agreement, the "Partnership Agreements") and is fully paid
(to the extent required under the PMC LP Partnership Agreement) and
nonassessable (except as such nonassessability may be affected by matters
described in the PMC LP Partnership Agreement); and Plains Marketing owns such
limited partner interest free and clear of all liens, encumbrances, security
interests, equities, charges or claims, except as provided in the Plains Bank
Credit Agreement and the Plains Letter of Credit Facility.

          (w) PMC NS is the sole general partner of PMC LP with a 0.01% general
partner interest in PMC LP; such general partner interest has been duly
authorized and validly issued in accordance with the PMC LP Partnership
Agreement; and PMC NS owns such general partner interest free and clear of all
liens, encumbrances, security interests, equities, charges or claims, except as
provided in the Plains Bank Credit Agreement and the Plains Letter of Credit
Facility.

                                       12

          (x)  PMC LLC owns 100% of the issued and outstanding capital stock of
PMC NS; such share capital has been duly authorized and validly issued in
accordance with the Memorandum and Articles of Association of PMC NS (as the
same may be amended and restated at or prior to the Closing Date, the "PMC NS
LLC Articles" and together with the PMC LLC Agreement, the Basin LLC Agreement
and the Partnership Agreements, the "Organization Agreements") as fully paid and
nonassessable shares (except as such nonassessability may be affected by the
laws of Nova Scotia); and PMC LLC owns such share capital free and clear of all
liens, encumbrances, security interests, equities, charges or claims, except as
provided in the Plains Bank Credit Agreement and the Plains Letter of Credit
Facility.

          (y)  None of the Plains Parties has any subsidiaries (other than Basin
LLC, Basin LP or a Plains Party) which, individually or considered as a whole,
would be deemed to be a significant subsidiary (as such term is defined in Rule
405 under the Act).

          (z)  Except as described in the Final Prospectus, there are no
preemptive rights or other rights to subscribe for or to purchase, nor any
restriction upon the voting or transfer of, any interests in the Partnership or
any Subsidiary pursuant to any of the Organization Agreements, or any agreement
or other instrument to which the Partnership or any Subsidiary is a party or by
which any one of them may be bound. Neither the filing of the Registration
Statement nor the offering or sale of the Units as contemplated by this
Agreement gives rise to any rights for or relating to the registration of any
Units or other securities of the Partnership or any Subsidiary, except such
rights as have been waived or satisfied. Except as described in the Final
Prospectus, there are no outstanding options or warrants to purchase any Common
Units or Subordinated Units or other partnership interests from the Partnership
or any Subsidiary. The Units, when issued and delivered against payment therefor
as provided herein, will conform in all material respects to the description
thereof contained in the Final Prospectus. The Partnership has all requisite
power and authority to issue, sell and deliver the Units, in accordance with and
upon the terms and conditions set forth in this Agreement, the Partnership
Agreement and the Registration Statement and Final Prospectus. At the Closing
Date and any Option Closing Date, all corporate, limited liability company and
partnership action, as the case may be, required to be taken by the Plains
Parties or any of their stockholders, members or partners for the authorization,
issuance, sale and delivery of the Units shall have been validly taken.

          (aa) The execution and delivery of, and the performance by each of the
Plains Parties of their respective obligations under, this Agreement have been
duly and validly authorized by each of the Plains Parties, and this Agreement
has been duly executed and delivered by each of the Plains Parties, and
constitutes the valid and legally binding agreement of each of the Plains
Parties, enforceable against each of the Plains Parties in accordance with its
terms, provided that the enforceability hereof may be limited by bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium and similar laws
relating to or affecting creditors' rights generally and by general principles
of equity (regardless of whether such enforceability is considered in a
proceeding in equity or at law) and except as rights to indemnity and
contribution hereunder may be limited by federal or state securities laws.

          (bb) The Partnership Agreement has been duly authorized, executed and
delivered by the General Partner and is a valid and legally binding agreement of
the General Partner, enforceable against the General Partner in accordance with
its terms; the Plains

                                       13

Marketing Partnership Agreement has been duly authorized, executed and delivered
by each of GP Inc. and the Partnership, and is a valid and legally binding
agreement of GP Inc. and the Partnership, enforceable against each of them in
accordance with its terms; the All American Partnership Agreement has been duly
authorized, executed and delivered by each of GP Inc. and Plains Marketing and
is a valid and legally binding agreement of GP Inc. and Plains Marketing
enforceable against each of them in accordance with its terms; the Basin LP
Partnership Agreement has been duly authorized, executed and delivered by each
of Basin LLC and All American and is a valid and legally binding agreement of
Basin LLC and All American, enforceable against each of them in accordance with
its terms; and the PMC LP Partnership Agreement has been duly authorized,
executed and delivered by each of PMC NS and Plains Marketing and is a valid and
legally binding agreement of PMC NS and Plains Marketing enforceable against
each of them in accordance with its terms; provided that, with respect to each
such agreement, the enforceability thereof may be limited by bankruptcy,
insolvency, fraudulent transfer, reorganization, moratorium and similar laws
relating to or affecting creditors' rights generally and by general principles
of equity (regardless of whether such enforceability is considered in a
proceeding in equity or at law).

          (cc) None of the offering, issuance and sale by the Partnership of the
Units, the execution, delivery and performance of this Agreement by the Plains
Parties, or the consummation of the transactions contemplated hereby (i)
conflicts or will conflict with or constitutes or will constitute a violation of
the agreement of limited partnership, limited liability company agreement,
certificate or articles of incorporation or bylaws or other organizational
documents of any of the Plains Parties, (ii) conflicts or will conflict with or
constitutes or will constitute a breach or violation of, a change of control or
a default (or an event which, with notice or lapse of time or both, would
constitute such an event), under any indenture, mortgage, deed of trust, loan
agreement, lease or other agreement or instrument to which any of the Plains
Parties is a party or by which any of them or any of their respective properties
may be bound, (iii) violates or will violate any statute, law or regulation or
any order, judgment, decree or injunction of any court or governmental agency or
body directed to any of the Plains Parties or any of their properties in a
proceeding to which any of them or their property is a party or (iv) will result
in the creation or imposition of any lien, charge or encumbrance upon any
property or assets of any of the Plains Parties, which conflicts, breaches,
violations or defaults, in the case of clauses (ii), (iii) or (iv), would have a
material adverse effect upon the condition (financial or other), business,
prospects, properties, net worth or results of operations of the Partnership and
the Subsidiaries, taken as a whole.

          (dd) No permit, consent, approval, authorization, order, registration,
filing or qualification of or with any court, governmental agency or body is
required in connection with the offering, issuance and sale by the Partnership
of the Units, the execution, delivery and performance of, or the consummation by
the Plains Parties of the transactions contemplated by, this Agreement, except
for such permits, consents, approvals and similar authorizations required under
the Act, the Exchange Act and state securities or "Blue Sky" laws.

          (ee) None of the Plains Parties is in (i) violation of its
Organization Agreement, certificate or articles of incorporation or bylaws or
other organizational documents, or of any law, statute, ordinance,
administrative or governmental rule or regulation applicable to it or of any
decree of any court or governmental agency or body having jurisdiction over it
or (ii)

                                       14

breach, default (or an event which, with notice or lapse of time or both, would
constitute such an event) or violation in the performance of any obligation,
agreement or condition contained in any bond, debenture, note or any other
evidence of indebtedness or in any agreement, indenture, lease or other
instrument to which it is a party or by which it or any of its properties may be
bound, which breach, default or violation would, if continued, have a material
adverse effect on the condition (financial or other), business, prospects,
properties, net worth or results of operations of the Partnership and the
Subsidiaries, taken as a whole, or could materially impair the ability of any of
the Plains Parties to perform its obligations under this Agreement. To the
knowledge of the Plains Parties, no third party to any indenture, mortgage, deed
of trust, loan agreement or other agreement or instrument to which any of the
Plains Parties is a party or by which any of them is bound or to which any of
their properties are subject, is in default under any such agreement, which
breach, default or violation would, if continued, have a material adverse effect
on the condition (financial or other), business, prospects, properties, net
worth or results of operations of the Partnership and the Subsidiaries, taken as
a whole.

          (ff) The accountants, PricewaterhouseCoopers LLP, who have certified
or shall certify the audited financial statements included or incorporated by
reference in the Registration Statement and the Final Prospectus (or any
amendment or supplement thereto), are independent public accountants with
respect to the Plains Parties as required by the Act and the applicable
published rules and regulations thereunder.

          (gg) At December 31, 2002, the Partnership would have had, on an as
adjusted basis as indicated in the Final Prospectus (and any amendment or
supplement thereto), a total capitalization as set forth therein. The financial
statements (including the related notes and supporting schedules) included or
incorporated by reference in the Registration Statement and the Final Prospectus
(and any amendment or supplement thereto) present fairly in all material
respects the financial position, results of operations and cash flows of the
entities purported to be shown thereby, at the dates and for the periods
indicated, and have been prepared in conformity with generally accepted
accounting principles applied on a consistent basis throughout the periods
indicated, except to the extent disclosed therein. The selected historical
information set forth in the Partnership's Annual Report on Form 10-K for the
year ended December 31, 2002 under the caption "Selected Financial and Operating
Data" is accurately presented in all material respects and prepared on a basis
consistent with the audited and unaudited historical consolidated financial
statements from which it has been derived, except as described therein.

          (hh) Except as disclosed in the Registration Statement and the Final
Prospectus (or any amendment or supplement thereto), subsequent to the
respective dates as of which such information is given in the Registration
Statement and the Final Prospectus (or any amendment or supplement thereto), (i)
none of the Plains Parties has incurred any liability or obligation, indirect,
direct or contingent, or entered into any transactions, not in the ordinary
course of business, that, singly or in the aggregate, is material to the Plains
Parties, taken as a whole, (ii) there has not been any material change in the
capitalization, or material increase in the short-term debt or long-term debt,
of the Plains Parties and (iii) there has not been any material adverse change,
or any development involving or which may reasonably be expected to involve,
singly or in the aggregate, a prospective material adverse change in the
condition (financial or other), business, prospects, properties, net worth or
results of operations of the Plains Parties, taken as a whole.

                                       15

     (ii) There are no legal or governmental proceedings pending or, to the
knowledge of the Plains Parties, threatened, against any of the Plains Parties,
or to which any of the Plains Parties is a party, or to which any of their
respective properties is subject, that are required to be described in the
Registration Statement or the Final Prospectus but are not described as
required, and there are no agreements, contracts, indentures, leases or other
instruments that are required to be described in the Registration Statement or
the Final Prospectus or to be filed as an exhibit to the Registration Statement
that are not described or filed as required by the Act.

     (jj) The Plains Parties have good and indefeasible title to all real
property and good title to all personal property described in the Final
Prospectus as being owned by them, free and clear of all liens, claims, security
interests or other encumbrances except (i) as provided in the Plains Bank Credit
Agreement and the Plains Letter of Credit Facility or as otherwise described in
the Final Prospectus and (ii) such as do not materially interfere with the use
of such properties taken as a whole as described in the Final Prospectus; and
all real property and buildings held under lease by any of the Plains Parties
are held under valid and subsisting and enforceable leases with such exceptions
as do not materially interfere with the use of such properties taken as a whole
as described in the Final Prospectus.

     (kk) The Partnership has not distributed and, prior to the later to occur
of (i) the Closing Date and (ii) completion of the distribution of the Units,
will not distribute, any prospectus (as defined under the Act) in connection
with the offering and sale of the Units other than the Registration Statement,
the Final Prospectus or other materials, if any, permitted by the Act, including
Rule 134 of the general rules and regulations thereunder.

     (ll) Each of the Plains Parties has such permits, consents, licenses,
franchises, certificates and authorizations of governmental or regulatory
authorities ("permits") as are necessary to own its properties and to conduct
its business in the manner described in the Final Prospectus, subject to such
qualifications as may be set forth in the Final Prospectus and except for such
permits the failure of which to have obtained would not have, individually or in
the aggregate, a material adverse effect upon the ability of the Partnership and
the Subsidiaries considered as a whole to conduct their businesses in all
material respects as currently conducted and as contemplated by the Final
Prospectus to be conducted; each of the Plains Parties has fulfilled and
performed all of its material obligations with respect to such permits and no
event has occurred which allows, or after notice or lapse of time would allow,
revocation or termination thereof or results in any impairment of the rights of
the holder of any such permit, except for such failures to perform, revocations,
terminations and impairments that would not have a material adverse effect upon
the ability of the Partnership and the Subsidiaries considered as a whole to
conduct their businesses in all material respects as currently conducted and as
contemplated by the Final Prospectus to be conducted, subject in each case to
such qualification as may be set forth in the Final Prospectus; and, except as
described in the Final Prospectus, none of such permits contains any restriction
that is materially burdensome to the Plains Parties considered as a whole.

     (mm) Each of the Plains Parties has such consents, easements, rights-of-way
or licenses from any person ("rights-of-way") as are necessary to conduct its
business in the manner described in the Final Prospectus, subject to such
qualifications as may be set forth in the Final

                                       16

Prospectus and except for such rights-of-way the failure of which to have
obtained would not have, individually or in the aggregate, a material adverse
effect upon the ability of the Partnership and the Subsidiaries considered as a
whole to conduct their businesses in all material respects as currently
conducted and as contemplated by the Final Prospectus to be conducted; each of
the Plains Parties has fulfilled and performed all its material obligations with
respect to such rights-of-way and no event has occurred which allows, or after
notice or lapse of time would allow, revocation or termination thereof or would
result in any impairment of the rights of the holder of any such rights-of-way,
except for such failures to perform, revocations, terminations and impairments
that will not have a material adverse effect upon the ability of the Partnership
and the Subsidiaries considered as a whole to conduct their businesses in all
material respects as currently conducted and as contemplated by the Final
Prospectus to be conducted, subject in each case to such qualification as may be
set forth in the Final Prospectus; and, except as described in the Final
Prospectus, none of such rights-of-way contains any restriction that is
materially burdensome to the Plains Parties considered as a whole.

     (nn) None of the Plains Parties is now, and after sale of the Units to be
sold by the Partnership hereunder and application of the net proceeds from such
sale as described in the Final Prospectus under the caption "Use of Proceeds,"
none of the Plains Parties will be, (i) an "investment company" or a company
"controlled by" an "investment company" within the meaning of the Investment
Company Act of 1940, as amended, (ii) a "public utility company," "holding
company" or a "subsidiary company" of a "holding company" or an "affiliate"
thereof, under the Public Utility Holding Company Act of 1935, as amended, (iii)
a "gas utility," within the meaning of Tex. Util. Code ss.121.001 or (iv) a
"public utility" or "utility" within the meaning of the Public Utility
Regulatory Act of Texas or under similar laws of any state in which any such
Plains Party does business.

     (oo) None of the Plains Parties has sustained since the date of the latest
audited financial statements included in the Final Prospectus any material loss
or interference with its business from fire, explosion, flood or other calamity
whether or not covered by insurance, or from any labor dispute or court or
governmental action, investigation, order or decree, otherwise than as set forth
or contemplated in the Final Prospectus.

     (pp) Except as described in the Final Prospectus, none of the Plains
Parties has violated any environmental, safety, health or similar law or
regulation applicable to its business relating to the protection of human health
and safety, the environment or hazardous or toxic substances or wastes,
pollutants or contaminants ("Environmental Laws"), or lacks any permits,
licenses or other approvals required of them under applicable Environmental Laws
to own, lease or operate their properties and conduct their business as
described in the Final Prospectus or is violating any terms and conditions of
any such permit, license or approval, which in each case would have a material
adverse effect on the condition (financial or other), business, prospects,
properties, net worth or results of operations of the Partnership and the
Subsidiaries, taken as a whole.

     (qq) No labor dispute by the employees of any of the Plains Parties exists
or, to the knowledge of the Plains Parties, is imminent, which might reasonably
be expected to have a material adverse effect on the condition (financial or
other), business, prospects, properties, net worth or results of operations of
the Partnership and the Subsidiaries, taken as a whole.

                                       17

     (rr) The Plains Parties maintain insurance covering their properties,
operations, personnel and businesses against such losses and risks as are
reasonably adequate to protect them and their businesses in a manner consistent
with other businesses similarly situated. None of the Plains Parties has
received notice from any insurer or agent of such insurer that substantial
capital improvements or other expenditures will have to be made in order to
continue such insurance, and all such insurance is outstanding and duly in force
on the date hereof and will be outstanding and duly in force on the Closing
Date.

     (ss) Except as described in the Final Prospectus, there is (i) no action,
suit or proceeding before or by any court, arbitrator or governmental agency,
body or official, domestic or foreign, now pending or, to the knowledge of the
Plains Parties, threatened, to which any of the Plains Parties, or any of their
respective subsidiaries, is or may be a party or to which the business or
property of any of the Plains Parties, or any of their respective subsidiaries,
is or may be subject, (ii) no statute, rule, regulation or order that has been
enacted, adopted or issued by any governmental agency or that has been proposed
by any governmental body and (iii) no injunction, restraining order or order of
any nature issued by a federal or state court or foreign court of competent
jurisdiction to which any of the Plains Parties, or any of their respective
subsidiaries, is or may be subject, that, in the case of clauses (i), (ii) and
(iii) above, is reasonably expected to (A) singly or in the aggregate have a
material adverse effect on the condition (financial or other), business,
prospects, properties, net worth or results of operations of the Partnership and
the Subsidiaries, taken as a whole, (B) prevent or result in the suspension of
the offering and issuance of the Units or (C) in any manner draw into question
the validity of this Agreement.

     (tt) The Common Units are listed on the New York Stock Exchange ("NYSE"),
and the Units have been approved for listing on the NYSE subject only to
official notice of issuance.

     7.   Indemnification and Contribution. (a) Each of the Plains Parties,
jointly and severally, agrees to indemnify and hold harmless each Underwriter,
the directors, officers, employees and agents of each Underwriter and each
person, if any, who controls any Underwriter within the meaning of Section 15 of
the Act or Section 20 of the Exchange Act from and against any and all losses,
claims, damages, liabilities and expenses (including reasonable costs of
investigation) arising out of or based upon any untrue statement or alleged
untrue statement of a material fact contained in the Registration Statement or
the Final Prospectus or in any amendment or supplement thereto, or arising out
of or based upon any omission or alleged omission to state therein a material
fact required to be stated therein or necessary to make the statements therein
not misleading, except insofar as such losses, claims, damages, liabilities or
expenses arise out of or are based upon any untrue statement or omission or
alleged untrue statement or omission which has been made therein or omitted
therefrom in reliance upon and in conformity with the information furnished in
writing to the Partnership, the General Partner or GP LLC by or on behalf of any
Underwriter expressly for use in connection therewith. The foregoing indemnity
agreement shall be in addition to any liability which any Plains Party may
otherwise have.

     (b)  If any action, suit or proceeding shall be brought against any
Underwriter, any director, officer, employee or agent of any Underwriter or any
person controlling any

                                       18

Underwriter in respect of which indemnity may be sought against a Plains Party,
such Underwriter or such director, officer, employee, agent or controlling
person shall promptly notify the Partnership in writing, and the Partnership,
the General Partner and GP LLC shall assume the defense thereof, including the
employment of counsel and payment of all reasonable fees and expenses. The
failure to notify the indemnifying party shall not relieve it from liability
which it may have to an indemnified party unless the indemnifying party is
foreclosed by reason of such delay from asserting a defense otherwise available
to it. Such Underwriter or any such director, officer, employee, agent or
controlling person shall have the right to employ separate counsel in any such
action, suit or proceeding and to participate in (but not control) the defense
thereof, but the fees and expenses of such counsel shall be at the expense of
such Underwriter or such director, officer, employee, agent or controlling
person unless (i) the Partnership, the General Partner and/or GP LLC has agreed
in writing to pay such fees and expenses, (ii) the Partnership, the General
Partner and GP LLC have failed to assume the defense and employ counsel or (iii)
the named parties to any such action, suit or proceeding (including any
impleaded parties) include both such Underwriter or such director, officer,
employee, agent or controlling person and the Partnership, the General Partner
or GP LLC, and such Underwriter or such director, officer, employee, agent or
controlling person shall have been advised by its counsel that representation of
such indemnified party and the Partnership, the General Partner and/or GP LLC by
the same counsel would be inappropriate under applicable standards of
professional conduct (whether or not such representation by the same counsel has
been proposed) due to actual or potential differing interests between them (in
which case the Partnership, the General Partner and GP LLC shall not have the
right to assume the defense of such action, suit or proceeding on behalf of such
Underwriter or such controlling person). It is understood, however, that the
Partnership, the General Partner and GP LLC shall, in connection with any one
such action, suit or proceeding or separate but substantially similar or related
actions, suits or proceedings in the same jurisdiction arising out of the same
general allegations or circumstances, be liable for the reasonable fees and
expenses of only one separate firm of attorneys (in addition to any local
counsel) at any time for all such Underwriters and directors, officers,
employees, agents and controlling persons not having actual or potential
differing interests with you or among themselves, which firm shall be designated
in writing by Goldman, Sachs & Co., and that all such fees and expenses shall be
reimbursed as they are incurred. None of the Plains Parties shall be liable for
any settlement of any such action, suit or proceeding effected without its
written consent, but if settled with such written consent, or if there be a
final judgment for the plaintiff in any such action, suit or proceeding, the
Plains Parties agree, jointly and severally, to indemnify and hold harmless any
Underwriter, to the extent provided in the preceding paragraph, and any such
controlling person from and against any loss, claim, damage, liability or
expense by reason of such settlement or judgment.

     (c)  Each Underwriter agrees, severally and not jointly, to indemnify and
hold harmless the Plains Parties, their respective directors and the officers
who sign the Registration Statement, and any person who controls the Plains
Parties within the meaning of Section 15 of the Act or Section 20 of the
Exchange Act, to the same extent as the foregoing indemnity from the Plains
Parties to each Underwriter, but only with respect to information furnished in
writing by or on behalf of such Underwriter through you expressly for use in the
Registration Statement or the Final Prospectus, or any amendment or supplement
thereto. If any action, suit or proceeding shall be brought against a Plains
Party, any of such directors and officers or any such controlling person based
on the Registration Statement or the Final Prospectus, or any

                                       19

amendment or supplement thereto, and in respect of which indemnity may be sought
against any Underwriter pursuant to this paragraph (c), such Underwriter shall
have the rights and duties given to the Plains Parties by paragraph (b) above
(except that if the Partnership, the General Partner or GP LLC shall have
assumed the defense thereof such Underwriter shall not be required to do so, but
may employ separate counsel therein and participate in (but not control) the
defense thereof, but the fees and expenses of such counsel shall be at such
Underwriter's expense), and the Plains Parties, any of such directors and
officers and any such controlling person shall have the rights and duties given
to the Underwriters by paragraph (b) above. The foregoing indemnity agreement
shall be in addition to any liability which the Underwriters may otherwise have.

     (d)  If the indemnification provided for in this Section 7 is unavailable
to an indemnified party under paragraph (a) or (c) hereof in respect of any
losses, claims, damages, liabilities or expenses referred to therein, then an
indemnifying party, in lieu of indemnifying such indemnified party, shall
contribute to the amount paid or payable by such indemnified party as a result
of such losses, claims, damages, liabilities or expenses (i) in such proportion
as is appropriate to reflect the relative benefits received by the Plains
Parties on the one hand and the Underwriters on the other hand from the offering
of the Units, or (ii) if the allocation provided by clause (i) above is not
permitted by applicable law, in such proportion as is appropriate to reflect not
only the relative benefits referred to in clause (i) above but also the relative
fault of the Plains Parties on the one hand and the Underwriters on the other in
connection with the statements or omissions that resulted in such losses,
claims, damages, liabilities or expenses, as well as any other relevant
equitable considerations. The relative benefits received by the Plains Parties
on the one hand and the Underwriters on the other shall be deemed to be in the
same proportion as the total net proceeds from the offering (before deducting
expenses) received by the Partnership bear to the total underwriting discounts
and commissions received by the Underwriters, in each case as set forth in the
table on the cover page of the Final Prospectus. The relative fault of the
Plains Parties on the one hand, and the Underwriters on the other hand shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by the Plains Parties or any
other affiliate of the Plains Parties on the one hand, or by the Underwriters on
the other hand, and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such statement or omission.

     (e)  The Plains Parties and the Underwriters agree that it would not be
just and equitable if contribution pursuant to this Section 7 were determined by
a pro rata allocation (even if the Underwriters were treated as one entity for
such purpose) or by any other method of allocation that does not take account of
the equitable considerations referred to in paragraph (d) above. The amount paid
or payable by an indemnified party as a result of the losses, claims, damages,
liabilities and expenses referred to in paragraph (d) above shall be deemed to
include, subject to the limitations set forth above, any legal or other expenses
reasonably incurred by such indemnified party in connection with investigating
any claim or defending any such action, suit or proceeding. Notwithstanding the
provisions of this Section 7, no Underwriter shall be required to contribute any
amount in excess of the amount by which the total price of the Units
underwritten by it and distributed to the public exceeds the amount of any
damages which such Underwriter has otherwise been required to pay by reason of
such untrue or alleged untrue statement or omission or alleged omission. No
person guilty of fraudulent misrepresentation

                                       20

(within the meaning of Section 11(f) of the Act) shall be entitled to
contribution from any person who was not guilty of such fraudulent
misrepresentation.

               (f)  No indemnifying party shall, without the prior written
consent of the indemnified party, effect any settlement of any pending or
threatened action, suit or proceeding in respect of which any indemnified party
is or could have been a party and indemnity could have been sought hereunder by
such indemnified party, unless such settlement includes an unconditional release
of such indemnified party from all liability on claims that are the subject
matter of such action, suit or proceeding.

               (g)  Any losses, claims, damages, liabilities or expenses for
which an indemnified party is entitled to indemnification or contribution under
this Section 7 shall be paid by the indemnifying party to the indemnified party
as such losses, claims, damages, liabilities or expenses are incurred. The
indemnity and contribution agreements contained in this Section 7 and the
representations and warranties of the Plains Parties set forth in this Agreement
shall remain operative and in full force and effect, regardless of (i) any
investigation made by or on behalf of any Underwriter or any person controlling
any Underwriter, the Plains Parties or any of their respective directors or
officers or any person controlling the Plains Parties, (ii) acceptance of any
Units and payment therefor in accordance with the terms of this Agreement, and
(iii) any termination of this Agreement. A successor to any Underwriter or any
person controlling any Underwriter, or to the Plains Parties or any of their
respective directors or officers or any person controlling a Plains Party shall
be entitled to the benefits of the indemnity, contribution and reimbursement
agreements contained in this Section 7.

               8.   Conditions of Underwriters' Obligations. The several
obligations of the Underwriters to purchase the Firm Units hereunder are subject
to the following conditions:

               (a)  If, at the time this Agreement is executed and delivered, it
is necessary for the registration statement or a post-effective amendment
thereto to be declared effective before the offering of the Units may commence,
the registration statement or such post-effective amendment shall have become
effective not later than 5:30 p.m., New York City time, on the date hereof, or
at such later date and time as shall be consented to in writing by Goldman,
Sachs & Co., and all filings required by Rule 424 under the Act shall be or have
been timely made; no stop order suspending the effectiveness of the registration
statement shall have been issued and no proceeding for that purpose shall have
been instituted or, to the knowledge of the Plains Parties or any Underwriter,
threatened by the Commission and any request of the Commission for additional
information (to be included in the Registration Statement or the Final
Prospectus or otherwise) shall have been complied with to your reasonable
satisfaction.

               (b)  Subsequent to the effective date of this Agreement, there
shall not have occurred (i) any change, or any development involving a
prospective change, in or affecting the condition (financial or other),
business, prospects, properties, net worth or results of operations of any of
the Plains Parties not contemplated by the Final Prospectus, which in your
opinion, would materially adversely affect the market for the Units, or (ii) any
event or development relating to or involving any of the Plains Parties or any
executive officer or director of any of such entities which makes any statement
made in the Final Prospectus untrue or which, in the opinion of the Partnership
and its counsel or the Underwriters and their counsel, requires the

                                       21

making of any addition to or change in the Final Prospectus in order to state a
material fact required by the Act or any other law to be stated therein or
necessary in order to make the statements therein not misleading, if amending or
supplementing the Final Prospectus to reflect such event or development would,
in your opinion, materially adversely affect the market for the Units.

               (c)  You shall have received on the Closing Date, an opinion of
Vinson & Elkins L.L.P., special counsel for the Plains Parties, dated the
Closing Date and addressed to you, to the effect that:

                    (i)   Each of the Partnership, the General Partner, Plains
         Marketing and Basin LP has been duly formed and is validly existing in
         good standing as a limited partnership under the Delaware LP Act with
         all necessary partnership power and authority to own or lease its
         properties and conduct its business and, in the case of the General
         Partner, to act as the general partner of the Partnership, in each case
         in all material respects as described in the Registration Statement and
         the Final Prospectus. Each of the Partnership, the General Partner,
         Plains Marketing and Basin LP is duly registered or qualified as a
         foreign limited partnership for the transaction of business and is in
         good standing under the laws of the jurisdictions set forth on Exhibit
         A to this opinion.

                    (ii)  All American has been duly formed and is validly
         existing in good standing as a limited partnership under the Texas LP
         Act with all necessary partnership power and authority to own or lease
         its properties and conduct its business, in each case in all material
         respects as described in the Registration Statement and the Final
         Prospectus. All American is duly registered or qualified as a foreign
         limited partnership for the transaction of business and is in good
         standing under the laws of the jurisdictions set forth on Exhibit A to
         this opinion.

                    (iii) GP Inc. has been duly incorporated and is validly
         existing in good standing under the laws of the State of Delaware, with
         all necessary corporate power and authority to own or lease its
         properties, to conduct its business and to act as general partner of
         Plains Marketing and All American, in each case in all material
         respects as described in the Registration Statement and the Final
         Prospectus. GP Inc. is duly registered or qualified as a foreign
         corporation for the transaction of business and is in good standing
         under the laws of the jurisdictions set forth on Exhibit A to this
         opinion.

                    (iv)  Each of GP LLC, PMC LLC and Basin LLC has been duly
         formed and is validly existing in good standing as a limited liability
         company under the Delaware LLC Act, with all necessary limited
         liability company power and authority to own or lease its properties
         and conduct its business and, in the cases of GP LLC and Basin LLC, to
         act as the general partner of the General Partner and Basin LP,
         respectively, in each case in all material respects as described in the
         Registration Statement and the Final Prospectus. Each of GP LLC, PMC
         LLC and Basin LLC is duly registered or qualified as a foreign limited
         liability company for the transaction of business and is in good
         standing under the laws of the jurisdictions set forth on Exhibit A to
         this opinion.

                                       22

                    (v)    GP LLC is the sole general partner of the General
         Partner, with a 1.0% general partner interest in the General Partner;
         such general partner interest has been duly authorized and validly
         issued in accordance with the General Partner Partnership Agreement;
         and GP LLC owns such general partner interest free and clear of all
         liens, encumbrances, security interests, equities, charges or claims
         (A) in respect of which a financing statement under the Uniform
         Commercial Code of the States of Delaware or Texas naming GP LLC as
         debtor is on file in the office of the Secretary of State of the States
         of Delaware or Texas or (B) otherwise known to such counsel, without
         independent investigation, other than those created by or arising under
         the Delaware LP Act.

                    (vi)   As of the date hereof, the issued and outstanding
         limited partner interests of the Partnership consist of 38,240,939
         Common Units, 1,307,190 Class B Units, 10,029,619 Subordinated Units
         and the Incentive Distribution Rights. All outstanding Common Units,
         Class B Units, Subordinated Units and Incentive Distribution Rights and
         the limited partner interests represented thereby have been duly
         authorized and validly issued in accordance with the Partnership
         Agreement and are fully paid (to the extent required under the
         Partnership Agreement) and nonassessable (except as such
         nonassessability may be affected by matters described in the Form 8-A).
         The authorized limited partner interests of the Partnership conform as
         to legal matters to the descriptions thereof contained in the Final
         Prospectus.

                    (vii)  The General Partner is the sole general partner of
         the Partnership, with a 2.0% general partner interest in the
         Partnership; such general partner interest has been duly authorized and
         validly issued in accordance with the Partnership Agreement; the
         General Partner owns 450,000 Subordinated Units and all of the
         Incentive Distribution Rights; and the General Partner owns such
         general partner interest, Subordinated Units and Incentive Distribution
         Rights free and clear of all liens, encumbrances, security interests,
         charges or claims (A) in respect of which a financing statement under
         the Uniform Commercial Code of the States of Delaware or Texas naming
         the General Partner as debtor is on file in the office of the Secretary
         of State of the States of Delaware or Texas or (B) otherwise known to
         such counsel, without independent investigation, other than those
         created by or arising under the Delaware LP Act, except, with respect
         to the Subordinated Units, (x) the economic interests attributable to
         distributions on such units as allocated in accordance with the General
         Partner Partnership Agreement and (y) the interest in such units held
         by grantees under the Plains 2001 Performance Option Plan.

                    (viii) The Firm Units to be issued and sold to the
         Underwriters by the Partnership pursuant to this Agreement and the
         limited partner interests represented thereby have been duly authorized
         by the Partnership Agreement and, when issued and delivered against
         payment therefor as provided in this Agreement, will be validly issued,
         fully paid (to the extent required under the Partnership Agreement) and
         nonassessable (except as such nonassessability may be affected by
         matters described in the Form 8-A).

                    (ix)   The Partnership owns 100% of the issued and
         outstanding capital stock of GP Inc.; such capital stock has been duly
         authorized and validly issued and is

                                       23

         fully paid and nonassessable; and the Partnership owns such capital
         stock free and clear of all liens, encumbrances, security interests,
         equities, charges or claims (A) in respect of which a financing
         statement under the Uniform Commercial Code of the States of Delaware
         or Texas naming the Partnership as debtor is on file in the office of
         the Secretary of State of the States of Delaware or Texas, (B)
         otherwise known to such counsel, without independent investigation,
         other than those created by or arising under the Delaware General
         Corporation Law, or (C) except as provided in the Plains Bank Credit
         Agreement and the Plains Letter of Credit Facility.

                    (x)   GP Inc. is the sole general partner of Plains
         Marketing with a .001% general partner interest in Plains Marketing;
         such general partner interest has been duly authorized and validly
         issued in accordance with the Plains Marketing Partnership Agreement;
         and GP Inc. owns such general partner interest free and clear of all
         liens, encumbrances, security interests, charges or claims (A) in
         respect of which a financing statement under the Uniform Commercial
         Code of the States of Delaware or Texas naming GP Inc. as debtor is on
         file in the office of the Secretary of State of the States of Delaware
         or Texas, (B) otherwise known to such counsel, without independent
         investigation, other than those created by or arising under the
         Delaware LP Act, or (C) except as provided in the Plains Bank Credit
         Agreement and the Plains Letter of Credit Facility.

                    (xi)  GP Inc. is the sole general partner of All American
         with a .001% general partner interest in All American; such general
         partner interest has been duly authorized and validly issued in
         accordance with the All American Partnership Agreement; and GP Inc.
         owns such general partner interest free and clear of all liens,
         encumbrances, security interests, charges or claims (A) in respect of
         which a financing statement under the Uniform Commercial Code of the
         States of Delaware or Texas naming GP Inc. as debtor is on file in the
         office of the Secretary of State of the States of Delaware or Texas,
         (B) otherwise known to such counsel, without independent investigation,
         other than those created by or arising under the Texas LP Act or (C)
         except as provided in the Plains Bank Credit Agreement and the Plains
         Letter of Credit Facility.

                    (xii) The Partnership is the sole limited partner of Plains
         Marketing with a 99.999% limited partner interest in Plains Marketing;
         such limited partner interest has been duly authorized and validly
         issued in accordance with the Plains Marketing Partnership Agreement
         and is fully paid (to the extent required under the Plains Marketing
         Partnership Agreement) and nonassessable (except as such
         nonassessability may be affected by Section 17-607 of the Delaware LP
         Act); and the Partnership owns such limited partner interest free and
         clear of all liens, encumbrances, security interests, charges or claims
         (A) in respect of which a financing statement under the Uniform
         Commercial Code of the States of Delaware or Texas naming the
         Partnership as debtor is on file in the office of the Secretary of
         State of the States of Delaware or Texas, (B) otherwise known to such
         counsel, without independent investigation, other than those created by
         or arising under the Delaware LP Act, or (C) except as provided in the
         Plains Bank Credit Agreement and the Plains Letter of Credit Facility.

                                       24

                    (xiii) Plains Marketing is the sole limited partner of All
         American with a 99.999% limited partner interest in All American; such
         limited partner interest has been duly authorized and validly issued in
         accordance with the All American Partnership Agreement and is fully
         paid (to the extent required under the All American Partnership
         Agreement) and nonassessable (except as such nonassessability may be
         affected by Section 6.07 of the Texas LP Act); and Plains Marketing
         owns such limited partner interest free and clear of all liens,
         encumbrances, security interests, charges or claims (A) in respect of
         which a financing statement under the Uniform Commercial Code of the
         States of Delaware or Texas naming Plains Marketing as debtor is on
         file in the office of the Secretary of State of the States of Delaware
         or Texas, (B) otherwise known to such counsel, without independent
         investigation, other than those created by or arising under the Texas
         LP Act, or (C) except as provided in the Plains Bank Credit Agreement
         and the Plains Letter of Credit Facility.

                    (xiv)  All American owns a 100% member interest in Basin
         LLC; such member interest has been duly authorized and validly issued
         in accordance with the Basin LLC Agreement and is fully paid (to the
         extent required under the Basin LLC Agreement) and nonassessable
         (except as such nonassessability may be affected by Section 18-607 of
         the Delaware LLC Act); and All American owns such member interest free
         and clear of all liens, encumbrances, security interests, charges or
         claims (A) in respect of which a financing statement under the Uniform
         Commercial Code of the States of Delaware or Texas naming All American
         as debtor is on file in the office of the Secretary of State of the
         States of Delaware or Texas, (B) otherwise known to such counsel,
         without independent investigation, other than those created by or
         arising under the Delaware LLC Act, or (C) except as provided in the
         Plains Bank Credit Agreement and the Plains Letter of Credit Facility.

                    (xv)   All American is the sole limited partner of Basin LP
         with a 99.999% limited partner interest in Basin LP; such limited
         partner interest has been duly authorized and validly issued in
         accordance with the Basin LP Partnership Agreement, and is fully paid
         (to the extent required under the Basin LP Partnership Agreement) and
         nonassessable (except as such nonassessability may be affected by
         Section 17-607 of the Delaware LP Act); and All American owns such
         limited partner interest free and clear of all liens, encumbrances,
         security interests, charges or claims (A) in respect of which a
         financing statement under the Uniform Commercial Code of the States of
         Delaware or Texas naming All American as debtor is on file in the
         office of the Secretary of State of the States of Delaware or Texas,
         (B) otherwise known to such counsel, without independent investigation,
         other than those created by or arising under the Delaware LP Act, or
         (C) except as provided in the Plains Bank Credit Agreement and the
         Plains Letter of Credit Facility.

                    (xvi)  Basin LLC is the sole general partner of Basin LP
         with a 0.001% general partner interest in Basin LP; such general
         partner interest has been duly authorized and validly issued in
         accordance with the Basin LP Partnership Agreement; and Basin LLC owns
         such general partner interest free and clear of all liens,
         encumbrances, security interests, charges or claims (A) in respect of
         which a financing statement under the Uniform Commercial Code of the
         State of Delaware naming Basin

                                       25

     LLC as debtor is on file in the office of the Secretary of State of the
     State of Delaware, (B) otherwise known to such counsel, without independent
     investigation, other than those created by or arising under the Delaware LP
     Act, or (C) except as provided in the Plains Bank Credit Agreement and the
     Plains Letter of Credit Facility.

               (xvii)   Plains Marketing owns a 100% member interest in PMC LLC;
     such member interest has been duly authorized and validly issued in
     accordance with the PMC LLC Agreement and is fully paid (to the extent
     required under the PMC LLC Agreement) and nonassessable (except as such
     nonassessability may be affected by Section 18-607 of the Delaware LLC
     Act); Plains Marketing owns such member interest free and clear of all
     liens, encumbrances, security interests, charges or claims (A) in respect
     of which a financing statement under the Uniform Commercial Code of the
     States of Delaware or Texas naming Plains Marketing as debtor is on file in
     the office of the Secretary of State of the States of Delaware or Texas,
     (B) otherwise known to such counsel, without independent investigation,
     other than those created by or arising under the Delaware LLC Act, or (C)
     except as provided in the Plains Bank Credit Agreement and the Plains
     Letter of Credit Facility.

               (xviii)  Plains Marketing owns its 99% limited partner interest
     in PMC LP free and clear of all liens, encumbrances, security interests,
     charges or claims (A) in respect of which a financing statement under the
     Uniform Commercial Code of the States of Delaware or Texas naming Plains
     Marketing as debtor is on file in the office of the Secretary of State of
     the States of Delaware or Texas, (B) otherwise known to such counsel,
     without independent investigation, other than those created by or arising
     under the Delaware LP Act, or (C) except as provided in the Plains Bank
     Credit Agreement and the Plains Letter of Credit Facility.

               (xix)    PMC LLC owns its 100% ownership interest in PMC NS free
     and clear of all liens, encumbrances, security interests, charges or claims
     (A) in respect of which a financing statement under the Uniform Commercial
     Code of the States of Delaware or Texas naming PMC LLC as debtor is on file
     in the office of the Secretary of State of the States of Delaware or Texas,
     (B) otherwise known to such counsel, without independent investigation,
     other than those created by or arising under the Delaware LLC Act, or (C)
     except as provided in the Plains Bank Credit Agreement and the Plains
     Letter of Credit Facility.

               (xx)     Except as have been waived or satisfied, there are no
     preemptive rights or other rights to subscribe for or to purchase, nor any
     restriction upon the voting or transfer of, any interests in the
     Partnership or any Subsidiary (other than PMC LP and PMC NS, as to which
     such counsel has not been asked to express an opinion) pursuant to any of
     the Organization Agreements (other than the PMC LP Partnership Agreement
     and the PMC NS LLC Articles, as to which such counsel has not been asked to
     express an opinion) or any other agreement or instrument known to such
     counsel to which the Partnership or any Subsidiary (other than PMC LP and
     PMC NS, as to which such counsel has not been asked to express an opinion)
     is a party or by which any one of them may be bound. To such counsel's
     knowledge, neither the filing of the Registration Statement nor the
     offering or sale of the Units as contemplated by this Agreement gives

                                       26

     rise to any rights for or relating to the registration of any Units or
     other securities of the Partnership or any Subsidiary (other than PMC LP
     and PMC NS, as to which such counsel has not been asked to express an
     opinion), except such rights as have been waived or satisfied. To such
     counsel's knowledge, except as described in the Final Prospectus or as have
     been issued pursuant to compensation plans adopted or administered by the
     General Partner, there are no outstanding options or warrants to purchase
     any Common Units or Subordinated Units or other partnership interests in
     the Partnership or any Subsidiary. The Partnership has all requisite power
     and authority to issue, sell and deliver the Units, in accordance with and
     upon the terms and conditions set forth in this Agreement, the Partnership
     Agreement and the Registration Statement and Final Prospectus.

               (xxi)    This Agreement has been duly authorized and validly
     executed and delivered by each of the Plains Parties.

               (xxii)   The Partnership Agreement has been duly authorized,
     executed and delivered by the General Partner and is a valid and legally
     binding agreement of the General Partner, enforceable against the General
     Partner in accordance with its terms; the Plains Marketing Partnership
     Agreement has been duly authorized, executed and delivered by each of GP
     Inc. and the Partnership, and is a valid and legally binding agreement of
     GP Inc. and the Partnership, enforceable against each of them in accordance
     with its terms; the All American Partnership Agreement has been duly
     authorized, executed and delivered by each of GP Inc. and Plains Marketing,
     and is a valid and legally binding agreement of GP Inc. and Plains
     Marketing, enforceable against each of them in accordance with its terms;
     the Basin LP Partnership Agreement has been duly authorized, executed and
     delivered by each of Basin LLC and All American and is a valid and legally
     binding agreement of Basin LLC and All American, enforceable against each
     of them in accordance with its terms; and the PMC LP Partnership Agreement
     has been duly authorized, executed and delivered by Plains Marketing;
     provided that, with respect to each such agreement other than the PMC LP
     Partnership Agreement, as to which counsel need not express an opinion, the
     enforceability thereof may be limited by (A) applicable bankruptcy,
     insolvency, fraudulent transfer, reorganization, moratorium or similar laws
     from time to time in effect affecting creditors' rights and remedies
     generally and by general principles of equity (regardless of whether such
     principles are considered in a proceeding in equity or at law) and (B)
     public policy, applicable law relating to fiduciary duties and
     indemnification and an implied covenant of good faith and fair dealing.

               (xxiii)  None of the offering, issuance and sale by the
     Partnership of the Units, the execution, delivery and performance of this
     Agreement by the Plains Parties or the consummation of the transactions
     contemplated hereby (A) constitutes or will constitute a violation of the
     Organization Agreements (other than the PMC LP Partnership Agreement and
     the PMC NS LLC Articles, as to which such counsel need not express an
     opinion) or the certificate or articles of incorporation or bylaws or other
     organizational documents of any of the Plains Parties, (B) constitutes or
     will constitute a breach or violation of, or a default under (or an event
     which, with notice or lapse of time or both, would constitute such an
     event), any agreement filed or incorporated by

                                       27

     reference as an exhibit to the Registration Statement (other than the
     Plains Bank Credit Agreement and the Plains Letter of Credit Facility, as
     to which such counsel need not express an opinion), (C) results or will
     result in any violation of the Delaware LP Act, the Delaware LLC Act, the
     DGCL, the laws of the State of Texas or federal law, or (D) results or will
     result in the creation or imposition of any lien, charge or encumbrance
     upon any property or assets of any of the Partnership or the Subsidiaries,
     which in the case of clauses (B), (C) or (D) would reasonably be expected
     to have a material adverse effect on the financial condition, business or
     results of operations of the Partnership and the Subsidiaries, taken as a
     whole.

               (xxiv)   No permit, consent, approval, authorization, order,
     registration, filing or qualification of or with any federal, Delaware, or
     Texas court, governmental agency or body having jurisdiction over the
     Plains Parties or any of their respective properties is required for the
     offering, issuance and sale by the Partnership of the Units, the execution,
     delivery and performance of this Agreement or the consummation of the
     transactions contemplated by this Agreement, except as may be required
     under state securities or "Blue Sky" laws, as to which such counsel need
     not express any opinion.

               (xxv)    The statements in the Registration Statement and Final
     Prospectus under the captions "Description of Our Common Units," "Cash
     Distribution Policy" and "Description of Our Partnership Agreement,"
     insofar as they constitute descriptions of agreements or refer to
     statements of law or legal conclusions, are accurate and complete in all
     material respects, and the Units, the Common Units, the Subordinated Units,
     the Class B Units and the Incentive Distribution Rights conform in all
     material respects to the descriptions thereof contained in the Registration
     Statement and Final Prospectus.

               (xxvi)   The opinion of Vinson & Elkins L.L.P. that is filed as
     Exhibit 8.1 to the Registration Statement is confirmed and the Underwriters
     may rely upon such opinion as if it were addressed to them.

               (xxvii)  The Registration Statement was declared effective under
     the Act on September 4, 2001; to the knowledge of such counsel, no stop
     order suspending the effectiveness of the Registration Statement has been
     issued and no proceedings for that purpose have been instituted or
     threatened by the Commission; and any required filing of the Final
     Prospectus pursuant to Rule 424(b) has been made in the manner and within
     the time period required by such Rule.

               (xxviii) The Registration Statement and the Final Prospectus
     (except for the financial statements and the notes and the schedules
     thereto and the other financial information included in the Registration
     Statement or the Final Prospectus, as to which such counsel need not
     express any opinion) comply as to form in all material respects with the
     requirements of the Act and the rules and regulations promulgated
     thereunder.

               (xxix)   To the knowledge of such counsel, (A) there is no legal
     or governmental proceeding pending or threatened to which any of the Plains
     Parties is a party or to which any of their respective properties is
     subject that is required to be disclosed in the Final Prospectus and is not
     so disclosed and (B) there are no agreements,

                                       28

     contracts or other documents to which any of the Plains Parties is a party
     that are required to be described in the Registration Statement or the
     Final Prospectus or to be filed as exhibits to the Registration Statement
     that are not described or filed as required.

               (xxx) None of the Plains Parties is an "investment company" as
     such term is defined in the Investment Company Act of 1940, as amended.

          In addition, such counsel shall state that they have participated in
conferences with officers and other representatives of the Plains Parties and
the independent public accountants of the Partnership and your representatives,
at which the contents of the Registration Statement and the Final Prospectus and
related matters were discussed, and although such counsel has not independently
verified, is not passing on, and is not assuming any responsibility for the
accuracy, completeness or fairness of the statements contained in, the
Registration Statement and the Final Prospectus (except to the extent specified
in the foregoing opinion), no facts have come to such counsel's attention that
lead such counsel to believe that the Registration Statement (other than (i) the
financial statements included or incorporated by reference therein, including
the notes and schedules thereto and the auditors' reports thereon, and (ii) the
other financial information included or incorporated by reference therein, as to
which such counsel need not comment), as of its effective date contained an
untrue statement of a material fact or omitted to state a material fact required
to be stated therein or necessary to make the statements therein not misleading,
or that the Final Prospectus (other than (i) the financial statements included
or incorporated by reference therein, including the notes and schedules thereto
and the auditors' reports thereon, and (ii) the other financial information
included or incorporated by reference therein, as to which such counsel need not
comment), as of its issue date and the Closing Date contained an untrue
statement of a material fact or omitted to state a material fact necessary to
make the statements therein, in the light of the circumstances under which they
were made, not misleading.

          In rendering such opinion, such counsel may (A) rely in respect of
matters of fact upon certificates of officers and employees of the Plains
Parties and upon information obtained from public officials, (B) assume that all
documents submitted to them as originals are authentic, that all copies
submitted to them conform to the originals thereof, and that the signatures on
all documents examined by them are genuine, (C) state that their opinion is
limited to federal laws, the Delaware LP Act, the Delaware LLC Act, the DGCL and
the laws of the States of New York and Texas, (D) with respect to the opinions
expressed in paragraphs (i), (ii), (iii) and (iv) above as to the due
qualification or registration as a foreign limited partnership, corporation or
limited liability company, as the case may be, of each of the Plains Parties,
state that such opinions are based upon certificates of foreign qualification or
registration provided by the Secretary of State of the States listed on Exhibit
A (each of which shall be dated as of a date not more than fourteen days prior
to the Closing Date and shall be provided to you) and (E) state that they
express no opinion with respect to (i) any permits to own or operate any real or
personal property or (ii) state or local taxes or tax statutes to which any of
the limited partners of the Partnership or any of the Plains Parties may be
subject.

          (d) You shall have received on the Closing Date, an opinion of
Fulbright & Jaworski L.L.P., special counsel for the Plains Parties, dated the
Closing Date and addressed to you, to the effect that none of the offering,
issuance or sale by the Partnership of the Units, the

                                       29

execution and delivery of this Agreement by the Plains Parties or the
consummation of the transactions contemplated hereby, result in a breach of, or
constitutes a default under (or an event which, with notice or lapse of time or
both, would constitute such an event) the provisions of any Credit Agreement (as
defined in Annex A to such opinion).

          In rendering such opinion, such counsel may (A) rely in respect of
matters of fact upon certificates of officers and employees of the Plains
Parties and upon information obtained from public officials, (B) assume that all
documents submitted to them as originals are authentic, that all copies
submitted to them conform to the originals thereof, and that the signatures on
all documents examined by them are genuine and (C) state that such opinions are
limited to the laws of the state of Texas, excepting therefrom municipal and
local ordinances and regulations.

          In rendering such opinion, such counsel shall state that such opinion
letter may be relied upon only by the Underwriters and their counsel in
connection with the transactions contemplated by this Agreement and no other use
or distribution of this opinion letter may be made without such counsel's prior
written consent.

          (e)  You shall have received on the Closing Date an opinion of Tim
Moore, general counsel for GP LLC, dated the Closing Date and addressed to you,
to the effect that:

               (i) To the knowledge of such counsel, none of the Plains Parties
     is in (A) breach or violation of the provisions of its Organization
     Agreement, certificate or articles of incorporation or bylaws or other
     organizational documents or (B) default (and no event has occurred which,
     with notice or lapse of time or both, would constitute such a default) or
     violation in the performance of any obligation, agreement or condition
     contained in any bond, debenture, note or any other evidence of
     indebtedness or in any agreement, indenture, lease or other instrument to
     which it is a party or by which it or any of its properties may be bound,
     which breach, default or violation would reasonably be expected to, if
     continued, have a material adverse effect on the financial condition,
     business or results of operations of the Partnership and the Subsidiaries,
     taken as a whole, or would reasonably be expected to materially impair the
     ability of any of the Plains Parties to perform their obligations under
     this Agreement.

               (ii) None of the offering, issuance and sale by the Partnership
     of the Units, the execution, delivery and performance by the Plains Parties
     of this Agreement or the consummation of the transactions contemplated
     hereby (A) constitutes or will constitute a breach or violation of, a
     change of control or a default (or an event which, with notice or lapse of
     time or both, would constitute such an event) under any bond, debenture,
     note or any other evidence of indebtedness, indenture or any other material
     agreement or instrument known to such counsel to which a Plains Party is a
     party or by which any one of them may be bound (other than any other
     agreement filed or incorporated by reference as an exhibit to the
     Registration Statement or any Credit Agreement (as defined in Annex A to
     such opinion)) or (B) violates or will violate any statute, law or
     regulation or any order, judgment, decree or injunction of any court or
     governmental agency or body directed to any of the Plains Parties or any of
     their properties in a proceeding to which any of them is a party, in the
     case of either (A) or (B),

                                       30

     which would, in the case of either (A) or (B) reasonably be expected to
     have a material adverse effect on the financial condition, business or
     results of operations of the Partnership and the Subsidiaries, taken as a
     whole.

               (iii) To the knowledge of such counsel, each of the Plains
     Parties has such permits, consents, licenses, franchises and authorizations
     ("permits") issued by the appropriate federal, state or local governmental
     or regulatory authorities as are necessary to own or lease its properties
     and to conduct its business in the manner described in the Final
     Prospectus, subject to such qualifications as may be set forth in the Final
     Prospectus, and except for such permits which, if not obtained, would not
     reasonably be expected to have, individually or in the aggregate, a
     material adverse effect upon the operations conducted by the Partnership
     and the Subsidiaries, taken as a whole; and, to the knowledge of such
     counsel, none of the Plains Parties has received any notice of proceedings
     relating to the revocation or modification of any such permits which,
     individually or in the aggregate, would reasonably be expected to have a
     material adverse effect upon the operations conducted by the Partnership
     and the Subsidiaries, taken as a whole.

               (iv)  Except as described in the Final Prospectus, to the
     knowledge of such counsel, there is no litigation proceeding, or
     governmental investigation pending or threatened against any of the Plains
     Parties which is reasonably likely to have a material adverse effect on the
     financial condition, business, properties, or results of operations of the
     Partnership and the Subsidiaries, taken as a whole.

          In addition, such counsel shall state that he has participated in
discussions with officers and other representatives of the Plains Parties and
the independent public accountants of the Partnership and your representatives,
at which the contents of the Registration Statement and the Final Prospectus and
related matters were discussed, and although such counsel has not independently
verified, is not passing on, and is not assuming any responsibility for the
accuracy, completeness or fairness of the statements contained in, the
Registration Statement and the Final Prospectus, no facts have come to such
counsel's attention that lead such counsel to believe that the Registration
Statement (other than (i) the financial statements included or incorporated by
reference therein, including the notes and schedules thereto and the auditors'
reports thereon, and (ii) the other financial information included or
incorporated by reference therein, as to which such counsel need not comment),
as of its effective date contained an untrue statement of a material fact or
omitted to state a material fact required to be stated therein or necessary to
make the statements therein not misleading, or that the Final Prospectus (other
than (i) the financial statements included or incorporated by reference therein,
including the notes and schedules thereto and the auditors' reports thereon, and
(ii) the other financial information included or incorporated by reference
therein, as to which such counsel need not comment), as of its issue date and
the Closing Date contained an untrue statement of a material fact or omitted to
state a material fact necessary to make the statements therein, in the light of
the circumstances under which they were made, not misleading.

          In rendering such opinion, such counsel may (A) rely in respect of
matters of fact upon certificates of officers and employees of the Plains
Parties and upon information obtained from public officials, (B) assume that all
documents submitted to him as originals are authentic,

                                       31

that all copies submitted to him conform to the originals thereof, and that the
signatures on all documents examined by him are genuine, (C) state that such
opinions are limited to federal laws and the Delaware LP Act, the Delaware LLC
Act and the DGCL and the laws of the State of Texas and (D) state that he
expresses no opinion with respect to state or local taxes or tax statutes.

          (f)  You shall have received on the Closing Date, an opinion of
Bennett Jones LLP with respect to the Province of Alberta, the Province of Nova
Scotia and the federal laws of Canada, dated the Closing Date and addressed to
you, to the effect that:

               (i)   PMC LP has been duly formed and is validly existing in good
     standing as a limited partnership under the laws of Alberta with all
     necessary partnership power and authority to own or lease its properties,
     in all material respects as described in the Registration Statement and the
     Final Prospectus, and to conduct its business as currently conducted and as
     proposed in the Final Prospectus to be conducted. PMC LP is duly registered
     extra-provincially for the transaction of business and is in good standing
     under the laws of the jurisdictions set forth on Exhibit A to this opinion.

               (ii)  PMC NS has been duly formed and is validly existing in good
     standing as an unlimited liability company under the laws of Nova Scotia,
     with all necessary corporate power and authority to own or lease its
     properties and act as general partner of PMC LP, in each case in all
     material respects, as described in the Registration Statement and the Final
     Prospectus, and to conduct its business as currently conducted and as
     proposed in the Final Prospectus to be conducted. PMC NS is duly registered
     extra-provincially for the transaction of business and is in good standing
     under the laws of the jurisdictions set forth on Exhibit A to this opinion.

               (iii) PMC NS is the sole general partner of PMC LP with a 0.01%
     interest in PMC LP; such interest has been duly authorized and validly
     issued in accordance with the PMC LP Partnership Agreement; and PMC NS owns
     such interest free and clear of all liens, encumbrances, security
     interests, charges or claims in respect of which a financing statement
     under the laws of Nova Scotia or Alberta naming PMC NS as debtor is on
     file, except for the security interests registered by Fleet National Bank
     and The Toronto-Dominion Bank at Alberta Personal Property Registry
     (registration no. 01050402997) and Nova Scotia Personal Property Registry
     (registration no. 4053623) against PMC LP and PMC NS.

               (iv)  Plains Marketing is the sole limited partner of PMC LP with
     a 99.99% limited partner interest in PMC LP; such interest has been duly
     authorized and validly issued in accordance with the PMC LP Partnership
     Agreement and is fully paid (to the extent required under the PMC LP
     Partnership Agreement) and nonassessable (except as such nonassessability
     may be affected by matters described in the PMC LP Partnership Agreement).

               (v)   PMC LLC is the registered holder of 100% of the issued and
     outstanding capital stock of PMC NS; such share capital has been duly
     authorized and validly issued in accordance with the PMC NS LLC Articles,
     as fully paid and

                                       32

nonassessable shares (except as such nonassessability may be affected by the
laws of Nova Scotia).

               (vi)   No permit, consent, approval, authorization, order,
registration, filing or qualification of or with any court, governmental agency
or body of the federal government of Canada or the Province of Alberta is
required for the offering, issuance and sale by the Partnership of the Units.

               (vii)  The PMC LP Partnership Agreement has been duly authorized,
executed and delivered by PMC NS and is a valid and legally binding agreement of
PMC NS and Plains Marketing enforceable against each of them in accordance with
its terms; provided that, with respect to each such agreement, the
enforceability thereof may be limited by (A) applicable bankruptcy, insolvency,
fraudulent transfer, reorganization, moratorium or similar laws from time to
time in effect affecting creditors' rights and remedies generally and by general
principles of equity (regardless of whether such principles are considered in a
proceeding in equity or at law) and (B) public policy, applicable law relating
to fiduciary duties and indemnification and an implied covenant of good faith
and fair dealing.

               (viii) None of the offering, issuance and sale by the Partnership
of the Units, the execution, delivery and performance of this Agreement by the
Plains Parties or the consummation of the transactions contemplated hereby
constitutes or will constitute a violation of the PMC LP Partnership Agreement
or the certificate or articles of incorporation, memorandum of association or
bylaws or other organizational documents of PMC NS.

               (ix)   To the knowledge of such counsel, each of PMC LP and PMC
NS has such permits, consents, licenses, franchises and authorizations
("permits") issued by the appropriate federal or provincial or regulatory
authorities as are necessary to own or lease its properties and to conduct its
business as currently conducted and as proposed in the Final Prospectus to be
conducted, subject to such qualifications as may be set forth in the Final
Prospectus, and except for such permits, consents, licenses, franchises and
authorizations which, if not obtained would not reasonably be expected to have,
individually or in the aggregate, a material adverse effect upon the operations
conducted by PMC LP and PMC NS taken as a whole.

          In rendering such opinion, such counsel may (A) rely in respect of
matters of fact upon certificates of officers and employees of the Plains
Parties and upon information obtained from public officials, (B) assume that all
documents submitted to them as originals are authentic, that all copies
submitted to them conform to the originals thereof, and that the signatures on
all documents examined by them are genuine, (C) state that such opinions are
limited to federal laws of Canada and the laws of the Provinces of Alberta and
Nova Scotia, excepting therefrom municipal and local ordinances and regulations
and (D) state that they express no opinion with respect to state or local taxes
or tax statutes to which any of the limited partners of the Partnership or any
of the Plains Parties may be subject.

                                       33

          In rendering such opinion, such counsel shall state that (A) Vinson &
Elkins L.L.P. is thereby authorized to rely upon such opinion letter in
connection with the transactions contemplated by this Agreement as if such
opinion letter were addressed and delivered to them on the date thereof and (B)
subject to the foregoing, such opinion letter may be relied upon only by the
Underwriters and their counsel in connection with the transactions contemplated
by this Agreement and no other use or distribution of such opinion letter may be
made without such counsel's prior written consent.

          (g)  You shall have received on the Closing Date an opinion of Baker
Botts L.L.P., counsel for the Underwriters, dated the Closing Date and addressed
to you, with respect to the issuance and sale of the Units, the Registration
Statement and the Final Prospectus (together with any supplement or amendment
thereto) and other related matters the Underwriters may reasonably require.

          (h)  You shall have received letters addressed to you, and dated the
date hereof and the Closing Date from PricewaterhouseCoopers LLP, independent
public accountants, substantially in the forms heretofore approved by you and
agreed to by PricewaterhouseCoopers LLP.

          (i)  (i) No stop order suspending the effectiveness of the
Registration Statement shall have been issued and no proceedings for that
purpose shall have been instituted or taken or, to the knowledge of the
Partnership, the General Partner or GP LLC, shall be threatened by the
Commission at or prior to the Closing Date; (ii) there shall not have been any
change in the partners' capital or stockholder's or members' equity of the
Partnership and the Subsidiaries, taken as a whole, or the General Partner or GP
LLC, as the case may be, nor any material increase in the short-term or the
long-term debt of the Partnership and the Subsidiaries, taken as a whole (other
than in the ordinary course of business) from that set forth or contemplated in
the Registration Statement or the Final Prospectus (or any amendment or
supplement thereto); (iii) there shall not have been, since the respective dates
as of which information is given in the Registration Statement and the Final
Prospectus (or any amendment or supplement thereto), except as may otherwise be
stated in the Registration Statement and the Final Prospectus (or any amendment
or supplement thereto), any material adverse change in or affecting the
condition (financial or other), business, prospects, properties, net worth or
results of operations of the Partnership and the Subsidiaries, taken as a whole;
(iv) the Partnership and the Subsidiaries shall not have any liabilities or
obligations, direct or contingent (whether or not in the ordinary course of
business), that are material to the Partnership and the Subsidiaries taken as a
whole other than those reflected in the Registration Statement or the Final
Prospectus (or any amendment or supplement thereto); and (v) all the
representations and warranties of the Plains Parties contained in this Agreement
shall be true and correct on and as of the date hereof and on and as of the
Closing Date as if made on and as of the Closing Date.

          (j)  The Plains Parties shall not have failed at or prior to the
Closing Date to have performed or complied in all material respects with any of
their agreements herein contained and required to be performed or complied with
by them hereunder at or prior to the Closing Date.

                                       34

          (k)  The NYSE shall have approved the Units for listing, subject only
to official notice of issuance and evidence of satisfactory distribution.

          (l)  The Plains Parties shall have furnished or caused to be furnished
to you such further certificates and documents as you shall have reasonably
requested.

          (m)  There shall have been furnished to you at the Closing Date a
certificate reasonably satisfactory to you, signed on behalf of the Partnership
by the President or any Vice President and the Chief Financial Officer of GP LLC
to the effect that: (A) the representations and warranties of each of the
Partnership, the General Partner and GP LLC contained in this Agreement are true
and correct at and as of the Closing Date as though made at and as of the
Closing Date; (B) each of the Partnership, the General Partner and GP LLC has in
all material respects performed all obligations required to be performed by it
pursuant to the terms of this Agreement at or prior to the Closing Date; (C) no
stop order suspending the effectiveness of the Registration Statement has been
issued and no proceeding for that purpose has been instituted or taken or, to
the knowledge of any of the Plains Parties, threatened by the Commission, and
all requests for additional information on the part of the Commission have been
complied with or otherwise satisfied; (D) no event contemplated by subsection
(i) of this Section 8 in respect of the Partnership or the Subsidiaries shall
have occurred; and (E) there has been no document required to be filed under the
Exchange Act that upon such filing would be deemed to be incorporated by
reference into the Final Prospectus that has not been so filed.

          (n)  There shall have been furnished to you at the Closing Date a
certificate reasonably satisfactory to you, signed on behalf of GP Inc. by the
President or any Vice President and the Chief Financial Officer of GP Inc. to
the effect that: (A) the representations and warranties of each of GP Inc.,
Plains Marketing and All American contained in this Agreement are true and
correct at and as of the Closing Date as though made at and as of the Closing
Date and (B) each of GP Inc., Plains Marketing and All American has in all
material respects performed all obligations and satisfied all conditions
required to be performed or satisfied by it pursuant to the terms of this
Agreement at or prior to the Closing Date.

          (o)  On or prior to the date hereof, the Partnership shall have
furnished to you a letter substantially in the form of Exhibit B hereto from
Plains Holdings LLC and from each officer and each director of GP LLC.

          All such opinions, certificates, letters and other documents referred
to in this Section 8 will be in compliance with the provisions hereof only if
they are reasonably satisfactory in form and substance to you and your counsel.
The Partnership shall furnish to the Underwriters conformed copies of such
opinions, certificates, letters and other documents in such number as they shall
reasonably request.

          The several obligations of the Underwriters to purchase Additional
Units hereunder are subject to the satisfaction on and as of any Option Closing
Date of the conditions set forth in this Section 8, except that, if any Option
Closing Date is other than the Closing Date, the certificates, opinions and
letters referred to in paragraphs (c) through (h) and (l) through (n) shall be
dated the Option Closing Date in question and the opinions called for by
paragraphs (c), (d), (e), (f) and (g), as applicable, shall be revised to
reflect the sale of Additional Units.

                                       35

          9. Expenses. The Partnership agrees to pay the following costs and
expenses and all other costs and expenses incident to the performance by it of
its obligations hereunder: (i) the preparation, printing or reproduction, and
filing with the Commission of the Registration Statement (including financial
statements and exhibits thereto), the Basic Prospectus, the Final Prospectus,
and each amendment or supplement to any of them; (ii) the printing (or
reproduction) and delivery (including postage, air freight charges and charges
for counting and packaging) of such copies of the Registration Statement, the
Basic Prospectus, the Final Prospectus, the Incorporated Documents and all
amendments or supplements to any of them as may be reasonably requested for use
in connection with the offering and sale of the Units; (iii) the preparation,
printing, authentication, issuance and delivery of certificates for the Units,
including any stamp taxes in connection with the original issuance and sale of
the Units; (iv) the printing (or reproduction) and delivery of this Agreement,
the preliminary and supplemental Blue Sky Memoranda, and all other agreements or
documents printed (or reproduced) and delivered in connection with the offering
of the Units; (v) the registration of the Common Units under the Exchange Act
and the listing of the Units on the NYSE; (vi) the registration or qualification
of the Units for offer and sale under the securities or Blue Sky laws of the
several states as provided in Section 5(f) hereof (including the reasonable
fees, expenses and disbursements of counsel for the Underwriters relating to the
preparation, printing or reproduction, and delivery of the preliminary and
supplemental Blue Sky Memoranda and such registration and qualification); (vii)
the filing fees in connection with any filings required to be made with the
National Association of Securities Dealers, Inc.; (viii) the transportation and
other expenses incurred by or on behalf of officers and employees of the
Partnership in connection with presentations to prospective purchasers of the
Units; and (ix) the fees and expenses of the Partnership's accountants and the
fees and expenses of counsel (including local and special counsel) for the
Partnership.

          It is understood, however, that except as otherwise provided in this
Section 9 or Section 5(i) hereof, the Underwriters will pay all of their own
costs and expenses, including the fees of their counsel, transfer taxes on any
resale of the Units by any Underwriter, any advertising expenses connected with
any offers they may make and the transportation and other expenses incurred by
the Underwriters on their own behalf in connection with presentations to
prospective purchasers of the Units.

          10. Effective Date of Agreement. This Agreement shall become
effective: (i) upon the execution and delivery hereof by the parties hereto or
(ii) if, at the time this Agreement is executed and delivered, it is necessary
for the Registration Statement or a post-effective amendment thereto to be
declared effective before the offering of the Units may commence, when
notification of the effectiveness of the Registration Statement or such
post-effective amendment has been released by the Commission. Until such time as
this Agreement shall have become effective, it may be terminated by the
Partnership by notifying you, or by you, by notifying the Partnership.

          If any one or more of the Underwriters shall fail or refuse to
purchase Units which it or they are obligated to purchase hereunder on the
Closing Date, and the aggregate number of Units which such defaulting
Underwriter or Underwriters are obligated but fail or refuse to purchase is not
more than one-tenth of the aggregate number of the Units which the Underwriters
are obligated to purchase on the Closing Date, each non-defaulting Underwriter
shall be

                                       36

obligated, severally, in the proportion which the number of Firm Units set forth
opposite its name in Schedule I hereto bears to the aggregate number of Firm
Units set forth opposite the names of all non-defaulting Underwriters or in such
other proportion as you may specify in accordance with the Agreement Among
Underwriters of Goldman, Sachs & Co., to purchase the Units which such
defaulting Underwriter or Underwriters are obligated, but fail or refuse, to
purchase. If any one or more of the Underwriters shall fail or refuse to
purchase Units which it or they are obligated to purchase on the Closing Date
and the aggregate number of Units with respect to which such default occurs is
more than one-tenth of the aggregate number of Units which the Underwriters are
obligated to purchase on the Closing Date and arrangements satisfactory to you
and the Partnership for the purchase of such Units by one or more non-defaulting
Underwriters or other party or parties approved by you and the Partnership are
not made within 36 hours after such default, this Agreement will terminate
without liability on the part of any party hereto (other than the defaulting
Underwriter). In any such case which does not result in termination of this
Agreement, either you or the Partnership shall have the right to postpone the
Closing Date, but in no event for longer than seven days, in order that the
required changes, if any, in the Registration Statement and the Final Prospectus
or any other documents or arrangements may be effected. If any one or more of
the Underwriters shall fail or refuse to purchase Additional Units which it or
they are obligated to purchase hereunder on the Option Closing Date, each
non-defaulting Underwriter shall be obligated, severally, in the proportion
which the number of Firm Units set forth opposite its name in Schedule I hereto
bears to the aggregate number of Firm Units set forth opposite the names of all
non-defaulting Underwriters or in such other proportion as you may specify in
accordance with the Agreement Among Underwriters of Goldman, Sachs & Co., to
purchase the Additional Units which such defaulting Underwriter or Underwriters
are obligated, but fail or refuse, to purchase. Any action taken under this
paragraph shall not relieve any defaulting Underwriter from liability in respect
of any such default of any such Underwriter under this Agreement. The term
"Underwriter" as used in this Agreement includes, for all purposes of this
Agreement, any party not listed in Schedule I hereto who, with your approval and
the approval of the Partnership, purchases Units which a defaulting Underwriter
is obligated, but fails or refuses, to purchase.

          Any notice under this Section 10 may be given by telegram, telecopy or
telephone but shall be subsequently confirmed by letter.

          11. Termination of Agreement. This Agreement shall be subject to
termination in your absolute discretion, without liability on the part of any
Underwriter to any Plains Party, by notice to the Partnership, if prior to the
Closing Date or any Option Closing Date (if different from the Closing Date and
then only as to the Additional Units), as the case may be, (i) trading in the
Common Units shall have been suspended by the Commission or the NYSE or trading
in securities generally on the New York Stock Exchange, the American Stock
Exchange or the Nasdaq National Market shall have been suspended or limited or
minimum prices shall have been established, (ii) a banking moratorium shall have
been declared either by federal or New York or Texas state authorities or a
material disruption in commercial banking or securities settlement or clearance
services in the United States shall have occurred, or (iii) there shall have
occurred any outbreak or escalation of hostilities, declaration by the United
States of a national emergency or war, or other calamity or crisis or any change
in financial, political or economic conditions in the United States or
elsewhere, the effect of which on financial markets is such as to make it, in
the sole judgment of the Underwriters, impractical or inadvisable to proceed
with

                                       37

the offering or delivery of the Units as contemplated by the Final Prospectus
(exclusive of any supplement thereto). Notice of such termination may be given
to the Partnership by telegram, telecopy or telephone and shall be subsequently
confirmed by letter.

          12. Information Furnished by the Underwriters. The statements set
forth in the fifth, seventh and eighth paragraphs under the caption
"Underwriting" in the Final Prospectus constitute the only information furnished
by or on behalf of the Underwriters through you as such information is referred
to in Sections 6(a) and 7 hereof.

          13. Miscellaneous. Except as otherwise provided in Sections 5, 10 and
11 hereof, notice given pursuant to any provision of this Agreement shall be in
writing and shall be delivered (i) if to any of the Plains Parties, at the
office of the Partnership at 333 Clay, Suite 1600, Houston, Texas 77002,
Attention: Tim Moore, or (ii) if to you, care of Goldman, Sachs & Co., 85 Broad
Street, 15th Floor, New York, New York 10004, Attention: Registration
Department.

          This Agreement has been and is made solely for the benefit of the
several Underwriters, the Plains Parties, their directors and officers, and the
other controlling persons referred to in Section 7 hereof and their respective
successors and assigns, to the extent provided herein, and no other person shall
acquire or have any right under or by virtue of this Agreement. Neither the term
"successor" nor the term "successors and assigns" as used in this Agreement
shall include a purchaser from any Underwriter of any of the Units in his status
as such purchaser.

          14. Applicable Law; Counterparts. This Agreement shall be governed by
and construed in accordance with the laws of the State of New York applicable to
contracts made and to be performed within the State of New York.

          This Agreement may be signed in various counterparts which together
constitute one and the same instrument. If signed in counterparts, this
Agreement shall not become effective unless at least one counterpart hereof
shall have been executed and delivered on behalf of each party hereto.

                                       38

          Please confirm that the foregoing correctly sets forth the agreement
among the Plains Parties and the Underwriters.

                              Very truly yours,

                              PLAINS ALL AMERICAN PIPELINE, L.P.

                              By: PLAINS AAP, L.P.
                                  its General Partner

                              By: PLAINS ALL AMERICAN GP LLC
                                  its General Partner

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

                              PLAINS AAP, L.P.

                              By: PLAINS ALL AMERICAN GP LLC
                                  its General Partner

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

                              PLAINS ALL AMERICAN GP LLC

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

                              PLAINS MARKETING, L.P.

                              By: PLAINS MARKETING GP INC.
                                  its General Partner

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

                                       39

                              ALL AMERICAN PIPELINE, L.P.

                              By: PLAINS MARKETING GP INC.
                                  its General Partner

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

                              PLAINS MARKETING GP INC.

                                             /s/ Phillip D. Kramer
                                  By: _________________________________________
                                      Name: Phillip D. Kramer
                                      Title: Executive Vice President and Chief
                                               Financial Officer

Confirmed as of the date first above
written on behalf of the Underwriters
named in Schedule I hereto.

Goldman, Sachs & Co.
A.G. Edwards & Sons, Inc.

    /s/ Goldman, Sachs & Co.
By: _________________________________________
    Goldman, Sachs & Co.

                                       40

                                   SCHEDULE I

                       Plains All American Pipeline, L.P.

                                                            Number of Firm Units
                             Underwriter                      to be Purchased
                             -----------                      ---------------
Goldman, Sachs & Co .....................................           1,380,000
A.G. Edwards & Sons, Inc. ...............................             920,000
                                                              ---------------
         Total                                                      2,300,000
                                                              ===============

                                       41

EXHIBIT 5.1 
 
[VINSON & ELKINS LETTERHEAD] 
 
March 6, 2003 
 
Plains All American Pipeline, L.P. 
333 Clay Street, Suite 1600 
Houston, Texas 77002 
 
Ladies and Gentlemen: 
 
We have acted as counsel to Plains All American Pipeline, L.P., a Delaware limited partnership (the “Partnership”), Plains AAP, L.P., a Delaware limited partnership and the general partner of the Partnership (the “General Partner”), and Plains All American GP LLC, a Delaware limited liability company and the general partner of the General Partner (“GP LLC”), in connection with the registration under the Securities Act of 1933, as amended (the “Securities Act”) of the offering and sale of up to an aggregate of 2,645,000 common units representing limited partner interests in the Partnership (the “Common Units”). 
 
As the basis for the opinion hereinafter expressed, we examined such statutes, including the Delaware Uniform Revised Limited Partnership Act, corporate records and documents, certificates of corporate and public officials, and other instruments and documents as we deemed necessary or advisable for the purposes of this opinion. In such examination, we assumed the authenticity of all documents submitted to us as originals and the conformity with the original documents of all documents submitted to us as copies. 
 
Based on the foregoing and on such legal considerations as we deem relevant, we are of the opinion that: 
 
 	1.	 	The Partnership has been duly formed and is validly existing as a limited partnership under the Delaware Revised Uniform Limited Partnership Act. 	
 
 	2.	 	The Common Units, when issued and paid for under the Partnership’s Registration Statement on Form S-3 (the “Registration Statement”), relating to the Common Units, will be duly authorized, validly issued, fully paid and nonassessable. 	
 
We hereby consent to the reference to us under the heading “Legal Matters” in the prospectus forming a part of the Registration Statement and to the filing of this opinion as an exhibit to the Registration Statement, but we do not thereby admit that we are within the class of persons whose consent is required under the provisions of the Securities Act or the rules and regulations of the Securities and Exchange Commission issued thereunder. 
 
Very truly yours, 
 
/s/ VINSON & ELKINS L.L.P. 
 
VINSON & ELKINS L.L.P. 

 
EXHIBIT 99.1 
 
Contacts:    Phillip D. Kramer                                                                         A. Patrick Diamond 
                    Executive Vice President and CFO                                             Manager, Special Projects 
                    713/646-4560 – 800/564-3036                                                      713/646-4487 – 800/564-3036 

FOR IMMEDIATE RELEASE 
 
Plains All American Pipeline, L.P. Announces 
Pricing of 2,300,000 Common Units 
 
(Houston – March 6, 2003) Plains All American Pipeline, L.P. (NYSE: PAA) today announced the issuance and sale by the Partnership of 2,300,000 Common Units at a public offering price of $24.80 per unit. Goldman, Sachs & Co. is serving as book-running lead manager for the offering with A.G. Edwards & Sons, Inc. as co-lead manager. 
 
Excluding the underwriters’ over-allotment option, net proceeds from the offering, including the general partner’s proportionate capital contribution and expenses associated with the offering, will be approximately $55.5 million. Such proceeds will be used to reduce indebtedness under the Partnership’s revolving credit facilities. Approximately $43 million of such indebtedness is attributable to the Partnership’s two recently announced acquisitions. The underwriters were also granted an option to purchase up to an additional 345,000 Common Units. 
 
Copies of the final prospectus relating to these securities may be obtained from Goldman, Sachs & Co., 85 Broad Street, New York, New York 10004. Any offering shall be made only by means of a final prospectus. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state. 
 
Except for the historical information contained herein, the matters discussed in this news release are forward-looking statements that involve certain risks and uncertainties. 
 
Plains All American Pipeline, L.P. is engaged in interstate and intrastate crude oil transportation, terminalling and storage, as well as crude oil gathering and marketing activities, primarily in Texas, Oklahoma, California, Louisiana and the Canadian Provinces of Alberta and Saskatchewan. The Partnership’s Common Units are traded on the New York Stock Exchange under the symbol “PAA”. The Partnership is headquartered in Houston, Texas. 

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