Document:

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                                                                     EXHIBIT 4.3

                   EXCHANGE AND REGISTRATION RIGHTS AGREEMENT

                                      AMONG

                       PLAINS ALL AMERICAN PIPELINE, L.P.,

                               PAA FINANCE CORP.,

                                 THE GUARANTORS

                                       AND

                              THE INITIAL PURCHASER

                         Dated as of September 25, 2002

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                       PLAINS ALL AMERICAN PIPELINE, L.P.
                                PAA FINANCE CORP.

                          7 3/4% Senior Notes due 2012

                   EXCHANGE AND REGISTRATION RIGHTS AGREEMENT

                                                              September 25, 2002

UBS Warburg LLC
677 Washington Blvd.
Stamford, Connecticut 06901

Ladies and Gentlemen:

     Plains All American Pipeline, L.P., a Delaware limited partnership (the
"Partnership"), PAA Finance Corp., a Delaware corporation ("PAA Finance," and
together with the Partnership, the "Issuers") and the Guarantors listed on
Schedule 1 hereto (the "Guarantors"), propose to issue and sell to UBS Warburg
LLC (the "Initial Purchaser"), upon the terms set forth in a purchase agreement
dated September 18, 2002 (the "Purchase Agreement"), $200,000,000 principal
amount of 7 3/4% Senior Notes due 2012 (the "Securities") relating to the
initial placement of the Securities (the "Initial Placement"). To induce the
Initial Purchaser to enter into the Purchase Agreement and to satisfy a
condition of your obligations thereunder, the Issuers and the Guarantors agree
with you for your benefit and the benefit of the holders from time to time of
the Securities (including the Initial Purchaser) (each a "Holder" and, together,
the "Holders"), as follows:

     1. Definitions. Capitalized terms used herein without definition shall have
their respective meanings set forth in the Purchase Agreement. As used in this
Agreement, the following capitalized defined terms shall have the following
meanings:

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

     "Affiliate" of any specified Person shall mean any other Person that,
directly or indirectly, is in control of, is controlled by, or is under common
control with, such specified Person. For purposes of this definition, control of
a Person shall mean the power, direct or indirect, to direct or cause the
direction of the management and policies of such Person whether by contract or
otherwise; and the terms "controlling" and "controlled" shall have meanings
correlative to the foregoing.

     "Broker-Dealer" shall mean any broker or dealer registered as such under
the Exchange Act.

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     "Business Day" shall mean any day other than a Saturday, a Sunday or a
legal holiday or a day on which banking institutions or trust companies are
authorized or obligated by law to close in New York City.

     "Commission" shall mean the Securities and Exchange Commission.

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

     "Exchange Offer Registration Period" shall mean the one-year period
following the consummation of the Registered Exchange Offer, exclusive of any
period during which any stop order shall be in effect suspending the
effectiveness of the Exchange Offer Registration Statement.

     "Exchange Offer Registration Statement" shall mean a registration statement
of the Issuers and the Guarantors on an appropriate form under the Act with
respect to the Registered Exchange Offer, all amendments and supplements to such
registration statement, including post-effective amendments thereto, in each
case including the Prospectus contained therein, all exhibits thereto and all
material incorporated by reference therein.

     "Exchanging Dealer" shall mean any Holder (which may include the Initial
Purchaser) that is a Broker-Dealer and elects to exchange for New Securities any
Securities that it acquired for its own account as a result of market-making
activities or other trading activities (but not directly from the Issuers and
the Guarantors or any Affiliate of the Issuers and the Guarantors) for New
Securities.

     "Final Memorandum" shall have the meaning set forth in the Purchase
Agreement.

     "Guarantors" shall have the meaning set forth in the preamble hereto and
shall also include any Guarantor's successor.

     "Holder" shall have the meaning set forth in the preamble hereto.

     "Indenture" shall mean the Indenture relating to the Securities and the New
Securities, dated as of September 25, 2002, among the Issuers and Wachovia Bank,
National Association, as trustee, as amended by the First Supplemental
Indenture, dated as of September 25, 2002, among the Issuers, the Guarantors and
the Trustee, and as the same may be amended from time to time in accordance with
the terms thereof.

     "Initial Placement" shall have the meaning set forth in the preamble
hereto.

     "Initial Purchaser" shall have the meaning set forth in the preamble
hereto.

     "Losses" shall have the meaning set forth in Section 7(d) hereof.

     "Majority Holders" shall mean the Holders of a majority of the aggregate
principal amount of Securities registered under a Registration Statement.

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     "Managing Underwriters" shall mean the investment banker or investment
bankers and manager or managers that shall administer an underwritten offering.

     "New Securities" shall mean debt securities of the Issuers identical in all
material respects to the Securities (except that the interest rate step-up
provisions and the transfer restrictions shall be eliminated) and to be issued
under the Indenture.

     "Prospectus" shall mean the prospectus included in any Registration
Statement (including, without limitation, a prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act), as amended or
supplemented by any prospectus supplement, with respect to the terms of the
offering of any portion of the Securities or the New Securities covered by such
Registration Statement, and all amendments and supplements thereto and all
material incorporated by reference therein.

     "Purchase Agreement" shall have the meaning set forth in the preamble
hereto.

     "Registered Exchange Offer" shall mean the proposed offer of the Issuers
and the Guarantors to issue and deliver to the Holders of the Securities that
are not prohibited by any law or policy of the Commission from participating in
such offer, in exchange for the Securities, a like aggregate principal amount of
the New Securities.

     "Registration Default" shall have the meaning set forth in Section 4
herein.

     "Registration Statement" shall mean any Exchange Offer Registration
Statement or Shelf Registration Statement that covers any of the Securities or
the New Securities pursuant to the provisions of this Agreement, any amendments
and supplements to such registration statement, including post-effective
amendments (in each case including the Prospectus contained therein), all
exhibits thereto and all material incorporated by reference therein.

     "Securities" shall have the meaning set forth in the preamble hereto.

     "Shelf Registration" shall mean a registration effected pursuant to Section
3 hereof.

     "Shelf Registration Period" has the meaning set forth in Section 3(b)
hereof.

     "Shelf Registration Statement" shall mean a "shelf" registration statement
of the Issuers and the Guarantors pursuant to the provisions of Section 3 hereof
which covers some or all of the Securities or New Securities, as applicable, on
an appropriate form under Rule 415 under the Act, or any similar rule that may
be adopted by the Commission, amendments and supplements to such registration
statement, including post-effective amendments, in each case including the
Prospectus contained therein, all exhibits thereto and all material incorporated
by reference therein.

     "Trustee" shall mean the trustee with respect to the Securities and the New
Securities under the Indenture.

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     "Trust Indenture Act" shall mean the Trust Indenture Act of 1939, as
amended from time to time.

     "underwriter" shall mean any underwriter of Securities in connection with
an offering thereof under a Shelf Registration Statement.

     2. Registered Exchange Offer. Except as set forth in Section 3, (a) The
Issuers and the Guarantors shall prepare and shall use their reasonable best
efforts to file with the Commission the Exchange Offer Registration Statement
with respect to the Registered Exchange Offer, not later than 60 days following
the date of the original issuance of the Securities (or if such 60th day is not
a Business Day, the next succeeding Business Day). The Issuers and the
Guarantors shall use their reasonable best efforts to cause the Exchange Offer
Registration Statement to become effective under the Act within 180 days of the
date of the original issuance of the Securities (or if such 180th day is not a
Business Day, the next succeeding Business Day).

     (b) Upon the effectiveness of the Exchange Offer Registration Statement,
the Issuers and the Guarantors shall promptly commence the Registered Exchange
Offer, it being the objective of such Registered Exchange Offer to enable each
Holder electing to exchange Securities for New Securities (assuming that such
Holder is not an Affiliate of the Issuers or the Guarantors, acquires the New
Securities in the ordinary course of such Holder's business, has no arrangements
with any Person to participate in the distribution of the New Securities and is
not prohibited by any law or policy of the Commission from participating in the
Registered Exchange Offer) to trade such New Securities from and after their
receipt without any limitations or restrictions under the Act and without
material restrictions under the securities laws of a substantial proportion of
the several states of the United States.

     (c) In connection with the Registered Exchange Offer, the Issuers and the
Guarantors shall:

          (i) mail to each Holder a copy of the Prospectus forming part of the
     Exchange Offer Registration Statement, together with an appropriate letter
     of transmittal and related documents;

          (ii) keep the Registered Exchange Offer open for not less than 20
     Business Days after the date notice thereof is mailed to the Holders (or,
     in each case, longer if required by applicable law);

          (iii) use their reasonable best efforts to keep the Exchange Offer
     Registration Statement continuously effective under the Act, supplemented
     and amended as required, under the Act to ensure that it is available for
     sales of New Securities by Exchanging Dealers during the Exchange Offer
     Registration Period;

          (iv) utilize the services of a bank depositary for the Registered
     Exchange Offer with an address in the Borough of Manhattan in New York
     City, which may be the Trustee or an Affiliate of the Trustee;

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          (v) permit Holders to withdraw tendered Securities at any time prior
     to the close of business, New York time, on the last Business Day on which
     the Registered Exchange Offer is open;

          (vi) prior to effectiveness of the Exchange Offer Registration
     Statement, provide a supplemental letter to the Commission (A) stating that
     the Issuers and the Guarantors are conducting the Registered Exchange Offer
     in reliance on the position of the Commission in Exxon Capital Holdings
     Corporation (pub. avail. May 13, 1988) and Morgan Stanley and Co., Inc.
     (pub. avail. June 5, 1991) and (B) including a representation that the
     Issuers and the Guarantors have not entered into any arrangement or
     understanding with any Person to distribute the New Securities to be
     received in the Registered Exchange Offer and that, to the best of the
     Issuers' and the Guarantors' information and belief, each Holder
     participating in the Registered Exchange Offer is acquiring the New
     Securities in the ordinary course of business and has no arrangement or
     understanding with any Person to participate in the distribution of the New
     Securities; and

          (vii) comply in all material respects with all applicable laws.

     (d) As soon as practicable after the close of the Registered Exchange
Offer, the Issuers and the Guarantors shall:

          (i) accept for exchange all Securities tendered and not validly
     withdrawn pursuant to the Registered Exchange Offer; and

          (ii) issue and cause the Trustee promptly to authenticate a global
     certificate representing New Securities exchanged for Securities and to
     deliver to each Holder of Securities a principal amount of New Securities
     equal to the principal amount of the Securities of such Holder so accepted
     for exchange.

     (e) Each Holder hereby acknowledges and agrees that any Broker-Dealer and
any such Holder using the Registered Exchange Offer to participate in a
distribution of the New Securities (x) could not under Commission policy as in
effect on the date of this Agreement rely on the position of the Commission in
Morgan Stanley and Co., Inc. (pub. avail. June 5, 1991) and Exxon Capital
Holdings Corporation (pub. avail. May 13, 1988), as interpreted in the
Commission's letter to Shearman & Sterling dated July 2, 1993 and similar
no-action letters; and (y) must comply with the registration and prospectus
delivery requirements of the Act in connection with any secondary resale
transaction and must be covered by an effective registration statement
containing the selling security holder information required by Item 507 or 508,
as applicable, of Regulation S-K under the Act if the resales are of New
Securities obtained by such Holder in exchange for Securities acquired by such
Holder directly from the Issuers or the Guarantors or one of their Affiliates.
Accordingly, each Holder participating in the Registered Exchange Offer shall be
required to represent to the Issuers and the Guarantors that, at the time of the
consummation of the Registered Exchange Offer:

          (i) any New Securities received by such Holder will be acquired in the
     ordinary course of business;

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          (ii) such Holder will have no arrangement or understanding with any
     Person to participate in the distribution of the Securities or the New
     Securities within the meaning of the Act; and

          (iii) such Holder is not an Affiliate of the Issuers or the
     Guarantors.

     3. Shelf Registration. (a) If (i) due to any change in law or applicable
interpretations thereof by the Commission's staff, the Issuers and the
Guarantors determine upon advice of their outside counsel that they are not
permitted to effect the Registered Exchange Offer as contemplated by Section 2
hereof; (ii) for any other reason the Registered Exchange Offer is not
consummated within 360 days of the date hereof; (iii) the Initial Purchaser so
requests with respect to Securities that are not eligible to be exchanged for
New Securities in the Registered Exchange Offer and that are held by it
following consummation of the Registered Exchange Offer; or (iv) any Holder
(other than the Initial Purchaser) is not eligible to participate in the
Registered Exchange Offer, the Issuers and the Guarantors shall effect a Shelf
Registration Statement in accordance with subsection (b) below.

     (b) (i) The Issuers and the Guarantors shall as promptly as practicable
(but in no event more than 60 days after so required or requested pursuant to
this Section 3), file with the Commission and thereafter shall use their
reasonable best efforts to cause to be declared effective under the Act, within
180 days after it is filed, a Shelf Registration Statement relating to the offer
and sale of the Securities or the New Securities, as applicable, by the Holders
thereof from time to time in accordance with the methods of distribution elected
by such Holders and set forth in such Shelf Registration Statement; provided,
however, that no Holder (other than the Initial Purchaser) shall be entitled to
have the Securities held by it covered by such Shelf Registration Statement
unless such Holder agrees in writing to be bound by all of the provisions of
this Agreement applicable to such Holder; and provided further, that with
respect to New Securities received by the Initial Purchaser in exchange for
Securities constituting any portion of an unsold allotment, the Issuers and the
Guarantors may, if permitted by current interpretations by the Commission's
staff, file a post-effective amendment to the Exchange Offer Registration
Statement containing the information required by Item 507 or 508 of Regulation
S-K, as applicable, in satisfaction of their obligations under this subsection
with respect thereto, and any such Exchange Offer Registration Statement, as so
amended, shall be referred to herein as, and governed by the provisions herein
applicable to, a Shelf Registration Statement.

          (ii) The Issuers and the Guarantors shall use their reasonable best
     efforts to keep the Shelf Registration Statement continuously effective,
     supplemented and amended as required by the Act, in order to permit the
     Prospectus forming part thereof to be usable by Holders for a period of two
     years from the date the Shelf Registration Statement is declared effective
     by the Commission or such shorter period that will terminate when all the
     Securities or New Securities, as applicable, covered by the Shelf
     Registration Statement have been sold pursuant to the Shelf Registration
     Statement (in any such case, such period being called the "Shelf
     Registration Period"). The Issuers and the Guarantors shall be deemed not
     to have used their best efforts to keep the Shelf Registration Statement
     effective during the requisite period if either Issuer or any

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     Guarantor voluntarily takes any action that would result in Holders of
     Securities covered thereby not being able to offer and sell such Securities
     during that period, unless (A) such action is required by applicable law;
     or (B) such action is taken by such Issuer or such Guarantor in good faith
     and for valid business reasons (not including avoidance of the Issuers' or
     the Guarantors' obligations hereunder), including the acquisition or
     divestiture of assets, so long as the Issuers and the Guarantors promptly
     thereafter comply with the requirements of Section 5(k) hereof, if
     applicable.

          (ii) The Issuers and the Guarantors shall cause the Shelf Registration
     Statement and the related Prospectus and any amendment or supplement
     thereto, as of the effective date of the Shelf Registration Statement or
     such amendment or supplement, (A) to comply in all material respects with
     the applicable requirements of the Act and the rules and regulations of the
     Commission; and (B) not to contain any 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.

     4. Additional Interest. (a) In the event that (i) the Issuers and the
Guarantors have not filed the Exchange Offer Registration Statement or the Shelf
Registration Statement with the Commission on or before the date on which such
Registration Statement is required to be so filed pursuant to Section 2(a) and
3(b), respectively, or (ii) such Exchange Offer Registration Statement or Shelf
Registration Statement has not been declared effective by the Commission under
the Act on or before the date on which such Registration Statement is required
to be declared effective under the Act pursuant to Section 2(a) or 3(b),
respectively, or (iii) the Exchange Offer has not been Consummated within 210
days after the date of issuance of the Securities, or (iv) the Exchange Offer
Registration Statement or Shelf Registration Statement required by Section 2(a)
or 2(b) hereof is filed and declared effective by the Commission under the Act
but shall thereafter cease to be effective (except as specifically permitted
herein) without being succeeded immediately by an additional Registration
Statement filed and declared effective by the Commission under the Act (each
such event referred to in clauses (i) through (iv) is referred to herein as a
"Registration Default"), then the interest rate on the New Securities will be
increased, for the period from the occurrence of the Registration Default until
such time as all Registration Defaults are cured (at which time the interest
rate will be reduced to its initial rate) by 0.25% per annum during the first
90-day period following the occurrence and during the continuation of the
Registration Default, and by 0.25% per annum for each subsequent 90-day period
during which such Registration Default continues. The interest rate will not at
any time be increased by greater than 1.00% per annum.

     (b) Without limiting the remedies available to the Initial Purchaser and
the Holders, the Issuers and the Guarantors acknowledge that any failure by the
Issuers or the Guarantors to comply with their obligations under Section 2(a)
and Section 3(b) hereof may result in material irreparable injury to the Initial
Purchasers or the Holders for which there is no adequate remedy at law, that it
will not be possible to measure damages for such injuries precisely and that, in
the event of any such failure, the Initial Purchasers or any Holder may

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obtain such relief as may be required to specifically enforce the Issuers' and
the Guarantors' obligations under Section 2(a) and Section 3(b) hereof.

     5. Additional Registration Procedures. In connection with any Shelf
Registration Statement and, to the extent applicable, any Exchange Offer
Registration Statement, the following provisions shall apply.

     (a) The Issuers and the Guarantors shall:

          (i) furnish to you, not less than five Business Days prior to the
     filing thereof with the Commission, a copy of any Exchange Offer
     Registration Statement and any Shelf Registration Statement, and each
     amendment thereof and each amendment or supplement, if any, to the
     Prospectus included therein (including all documents incorporated by
     reference therein after the initial filing) and shall use their reasonable
     best efforts to reflect in each such document, when so filed with the
     Commission, such comments as you reasonably propose;

          (ii) include the information set forth in Annex A hereto on the facing
     page of the Exchange Offer Registration Statement, in Annex B hereto in the
     forepart of the Exchange Offer Registration Statement in a section setting
     forth details of the Exchange Offer, in Annex C hereto in the underwriting
     or plan of distribution section of the Prospectus contained in the Exchange
     Offer Registration Statement, and in Annex D hereto in the letter of
     transmittal delivered pursuant to the Registered Exchange Offer;

          (iii) if requested by the Initial Purchaser, include the information
     required by Item 507 or 508 of Regulation S-K, as applicable, in the
     Prospectus contained in the Shelf Registration Statement; and

          (iv) in the case of a Shelf Registration Statement, include the names
     of the Holders that propose to sell Securities pursuant to the Shelf
     Registration Statement as selling security holders.

     (b) The Issuers and the Guarantors shall ensure that:

          (i) any Registration Statement and any amendment thereto and any
     Prospectus forming part thereof and any amendment or supplement thereto
     comply in all material respects with the Act and the rules and regulations
     thereunder; and

          (ii) any Registration Statement and any amendment thereto do not, when
     they become effective, 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.

     (c) The Issuers and the Guarantors shall advise you, the Holders of
Securities covered by any Shelf Registration Statement and any Exchanging Dealer
under any Exchange Offer Registration Statement that has provided in writing to
the Issuers and the Guarantors a telephone or facsimile number and address for
notices, and, if requested in writing by you or any

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such Holder or Exchanging Dealer, shall confirm such advice in writing (which
notice pursuant to clauses (ii)-(v) hereof shall be accompanied by an
instruction to suspend the use of the Prospectus until the Issuers and the
Guarantors shall have remedied the basis for such suspension):

          (i) when a Registration Statement and any amendment thereto have been
     filed with the Commission and when the Registration Statement or any
     post-effective amendment thereto has become effective;

          (ii) of any request by the Commission for any amendment or supplement
     to the Registration Statement or the Prospectus or for additional
     information;

          (iii) of the issuance by the Commission of any stop order suspending
     the effectiveness of the Registration Statement or the initiation of any
     proceedings for that purpose;

          (iv) of the receipt by the Issuers and the Guarantors of any
     notification with respect to the suspension of the qualification of the
     securities included therein for sale in any jurisdiction or the initiation
     of any proceeding for such purpose; and

          (v) of the happening of any event that requires any change in the
     Registration Statement or the Prospectus so that, as of such date, the
     statements therein are not misleading and do not omit to state a material
     fact required to be stated therein or necessary to make the statements
     therein (in the case of the Prospectus, in the light of the circumstances
     under which they were made) not misleading.

     (d) The Issuers and the Guarantors shall use their reasonable best efforts
to obtain the withdrawal of any order suspending the effectiveness of any
Registration Statement or the qualification of the securities therein for sale
in any jurisdiction at the earliest possible time.

     (e) The Issuers and the Guarantors shall furnish to each Holder of
Securities covered by any Shelf Registration Statement, without charge, at least
one copy of such Shelf Registration Statement and any post-effective amendment
thereto, including all material incorporated therein by reference, and, if the
Holder so requests in writing, all exhibits thereto (including exhibits
incorporated by reference therein).

     (f) The Issuers and the Guarantors shall, during the Shelf Registration
Period, deliver to each Holder of Securities covered by any Shelf Registration
Statement, without charge, as many copies of the Prospectus (including each
preliminary Prospectus) included in such Shelf Registration Statement and any
amendment or supplement thereto as such Holder may reasonably request. The
Issuers and the Guarantors consent to the use of the Prospectus or any amendment
or supplement thereto by each of the selling Holders of Securities in connection
with the offering and sale of the Securities covered by the Prospectus, or any
amendment or supplement thereto, included in the Shelf Registration Statement.

     (g) The Issuers and the Guarantors shall furnish to each Exchanging Dealer
which so requests, without charge, at least one copy of the Exchange Offer
Registration Statement and any post-effective amendment thereto, including all
material incorporated by

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reference therein, and, if the Exchanging Dealer so requests in writing, all
exhibits thereto (including exhibits incorporated by reference therein).

     (h) The Issuers and the Guarantors shall promptly deliver to the Initial
Purchaser, each Exchanging Dealer and each other Person required to deliver a
Prospectus during the effectiveness of the Exchange Offer Registration
Statement, without charge, as many copies of the Prospectus included in such
Exchange Offer Registration Statement and any amendment or supplement thereto as
any such Person may reasonably request. The Issuers and the Guarantors consent
to the use of the Prospectus or any amendment or supplement thereto by the
Initial Purchaser, any Exchanging Dealer and any such other Person that may be
required to deliver a Prospectus following the Registered Exchange Offer in
connection with the offering and sale of the New Securities covered by the
Prospectus, or any amendment or supplement thereto, included in the Exchange
Offer Registration Statement.

     (i) Prior to the Registered Exchange Offer or any other offering of
Securities pursuant to any Registration Statement, the Issuers and the
Guarantors shall arrange, if necessary, for the qualification of the Securities
or the New Securities for sale under the laws of such jurisdictions as any
Holder shall reasonably request and will maintain such qualification in effect
so long as required; provided that in no event shall either Issuer or any
Guarantor be obligated to qualify to do business in any jurisdiction where it is
not then so qualified or to take any action that would subject it to service of
process in suits, other than those arising out of the Initial Placement, the
Registered Exchange Offer or any offering pursuant to a Shelf Registration
Statement, in any such jurisdiction where it is not then so subject.

     (j) If any of the Securities or the New Securities are not issued in global
form, then the Issuers and the Guarantors shall cooperate with the Holders of
Securities to facilitate the timely preparation and delivery of certificates
representing New Securities or Securities to be issued or sold pursuant to any
Registration Statement free of any restrictive legends and in such denominations
and registered in such names as Holders may request.

     (k) Upon the occurrence of any event contemplated by subsections (c)(ii) or
(v) above, the Issuers and the Guarantors shall promptly prepare a
post-effective amendment to the applicable Registration Statement or an
amendment or supplement to the related Prospectus or file any other required
document so that, as thereafter delivered to Initial Purchaser of the securities
included therein, the Prospectus will not include an untrue statement of a
material fact or omit to state any material fact necessary to make the
statements therein, in the light of the circumstances under which they were
made, not misleading. In such circumstances, the period of effectiveness of the
Exchange Offer Registration Statement provided for in Section 2 and the Shelf
Registration Statement provided for in Section 3(b) shall each be extended by
the number of days from and including the date of the giving of a notice of
suspension pursuant to Section 5(c) to and including the date when the Initial
Purchaser, the Holders of the Securities and any known Exchanging Dealer shall
have received such amended or supplemented Prospectus pursuant to this Section.

     (l) Not later than the effective date of any Registration Statement, the
Issuers and the Guarantors shall provide a CUSIP number for the Securities or
the New Securities, as the case may be, registered under such Registration
Statement and provide the Trustee with

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certificates for such Securities or New Securities, in a form eligible for
deposit with The Depository Trust Company.

     (m) The Issuers and the Guarantors shall comply with all applicable rules
and regulations of the Commission and shall make generally available to the
Issuers' security holders as soon as practicable after the effective date of the
applicable Registration Statement an earnings statement satisfying the
provisions of Section 11(a) of the Act.

     (n) The Issuers and the Guarantors shall cause the Indenture to be
qualified under the Trust Indenture Act in a timely manner.

     (o) The Issuers and the Guarantors may require each Holder of Securities to
be sold pursuant to any Shelf Registration Statement to furnish to the Issuers
and the Guarantors such information regarding the Holder and the distribution of
such Securities as the Issuers and the Guarantors may from time to time
reasonably require for inclusion in such Registration Statement. The Issuers and
the Guarantors may exclude from such Shelf Registration Statement the Securities
of any Holder that unreasonably fails to furnish such information within a
reasonable time after receiving such request.

     (p) In the case of any Shelf Registration Statement, the Issuers and the
Guarantors shall enter into such agreements and take all other appropriate
actions (including if requested an underwriting agreement in customary form) in
order to expedite or facilitate the registration or the disposition of the
Securities, and in connection therewith, if an underwriting agreement is entered
into, cause the same to contain indemnification provisions and procedures no
less favorable than those set forth in Section 7 (or such other provisions and
procedures acceptable to the Majority Holders and the Managing Underwriters, if
any, with respect to all parties to be indemnified pursuant to Section 7).

     (q) In the case of any Shelf Registration Statement, the Issuers and the
Guarantors shall:

          (i) make reasonably available for inspection by the Holders of
     Securities to be registered thereunder, any underwriter participating in
     any disposition pursuant to such Registration Statement, and any attorney,
     accountant or other agent retained by the Holders or any such underwriter
     all relevant financial and other records, pertinent corporate documents and
     properties of the Issuers and the Guarantors and their respective
     subsidiaries;

          (ii) cause the Issuers' and the Guarantors' respective officers,
     directors and employees to supply all relevant information reasonably
     requested by the Holders or any such underwriter, attorney, accountant or
     agent in connection with any such Registration Statement as is customary
     for similar due diligence examinations; provided, however, that any
     information that is designated in writing by the Issuers or the Guarantors,
     in good faith, as confidential at the time of delivery of such information
     shall be kept confidential by the Holders or any such underwriter,
     attorney, accountant or agent, unless such disclosure is made in connection
     with a court proceeding or required

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     by law, or such information becomes available to the public generally or
     through a third party without an accompanying obligation of
     confidentiality;

          (iii) make such representations and warranties to the Holders of
     Securities registered thereunder and the underwriters, if any, in form,
     substance and scope as are customarily made by issuers to underwriters in
     primary underwritten offerings and covering matters including, but not
     limited to, those set forth in the Purchase Agreement;

          (iv) obtain opinions of counsel to the Issuers and the Guarantors and
     updates thereof (which counsel and opinions (in form, scope and substance)
     shall be reasonably satisfactory to the Managing Underwriters, if any)
     addressed to each selling Holder and the underwriters, if any, covering
     such matters as are customarily covered in opinions requested in
     underwritten offerings and such other matters as may be reasonably
     requested by such Holders and underwriters;

          (v) obtain "cold comfort" letters and updates thereof from the
     independent certified public accountants of the Issuers and the Guarantors
     (and, if necessary, any other independent certified public accountants of
     any subsidiary of the Issuers and the Guarantors or of any business
     acquired by the Issuers and the Guarantors for which financial statements
     and financial data are, or are required to be, included in the Registration
     Statement), addressed to each selling Holder of Securities registered
     thereunder and the underwriters, if any, in customary form and covering
     matters of the type customarily covered in "cold comfort" letters in
     connection with primary underwritten offerings; and

          (vi) deliver such documents and certificates as may be reasonably
     requested by the Majority Holders and the Managing Underwriters, if any,
     including those to evidence compliance with Section 5(k) and with any
     customary conditions contained in the underwriting agreement or other
     agreement entered into by the Issuers or the Guarantors.

The actions set forth in clauses (iii), (iv), (v) and (vi) of this Section shall
be performed at (A) the effectiveness of such Registration Statement and each
post-effective amendment thereto; and (B) each closing under any underwriting or
similar agreement as and to the extent required thereunder.

     (r) [omitted]

     (s) [omitted]

     (t) [omitted]

     (u) In the event that any Broker-Dealer shall underwrite any Securities or
participate as a member of an underwriting syndicate or selling group or "assist
in the distribution" (within the meaning of the Conduct Rules and the By-Laws of
the National Association of Securities Dealers, Inc.) thereof, whether as a
Holder of such Securities or as an underwriter, a placement or sales agent or a
broker or dealer in respect thereof, or otherwise,

                                       12

<PAGE>

assist such Broker-Dealer in complying with the requirements of such Rules and
By-Laws, including, without limitation, by:

          (i) if such Rules or By-Laws shall so require, engaging a "qualified
     independent underwriter" (as defined in such Rules) to participate in the
     preparation of the Registration Statement, to exercise usual standards of
     due diligence with respect thereto and, if any portion of the offering
     contemplated by such Registration Statement is an underwritten offering or
     is made through a placement or sales agent, to recommend the yield of such
     Securities;

          (ii) indemnifying any such qualified independent underwriter to the
     extent of the indemnification of underwriters provided in Section 7 hereof;
     and

          (iii) providing such information to such Broker-Dealer as may be
     required in order for such Broker-Dealer to comply with the requirements of
     such Rules.

          (iv) The Issuers and the Guarantors shall use their reasonable best
     efforts to take all other steps necessary to effect the registration of the
     Securities or the New Securities, as the case may be, covered by a
     Registration Statement.

     6. Registration Expenses. The Issuers and the Guarantors bear all expenses
incurred in connection with the performance of their obligations under Sections
2, 3 and 5 hereof and, in the event of any Shelf Registration Statement, will
reimburse the Holders for the reasonable fees and disbursements of one firm or
counsel designated by the Majority Holders to act as counsel for the Holders in
connection therewith, and, in the case of any Exchange Offer Registration
Statement, will reimburse the Initial Purchaser for the reasonable fees and
disbursements of counsel acting in connection therewith.

     7. Indemnification and Contribution. (a) The Issuers and each Guarantor
agree to indemnify and hold harmless each Holder of Securities or New
Securities, as the case may be, covered by any Registration Statement (including
the Initial Purchaser and, with respect to any Prospectus delivery as
contemplated in Section 5(h) hereof, each Exchanging Dealer), the directors,
officers, employees and agents of each such Holder and each Person who controls
any such Holder within the meaning of either the Act or the Exchange Act against
any and all losses, claims, damages or liabilities, joint or several, to which
they or any of them may become subject under the Act, the Exchange Act or other
Federal or state statutory law or regulation, at common law or otherwise,
insofar as such losses, claims, damages or liabilities (or actions in respect
thereof) arise out of or are based upon any untrue statement or alleged untrue
statement of a material fact contained in the Registration Statement as
originally filed or in any amendment thereof, or in any preliminary Prospectus
or the Prospectus, or in any amendment thereof or supplement thereto, or arise
out of or are based upon the omission or alleged omission to state therein a
material fact required to be stated therein or necessary to make the statements
therein not misleading, and agree to reimburse each such indemnified party, as
incurred, for any legal or other expenses reasonably incurred by them in
connection with investigating or defending any such loss, claim, damage,
liability or action;

                                       13

<PAGE>

provided, however, that the Issuers and the Guarantors will not be liable in any
case to the extent that any such loss, claim, damage or liability arises out of
or is based upon any such untrue statement or alleged untrue statement or
omission or alleged omission made therein in reliance upon and in conformity
with written information furnished to the Issuers or the Guarantors by or on
behalf of any such Holder specifically for inclusion therein. This indemnity
agreement will be in addition to any liability which the Issuers or the
Guarantors may otherwise have.

     The Issuers and each Guarantor also agree to indemnify or contribute as
provided in Section 7(d) to Losses of any underwriter of Securities or New
Securities, as the case may be, registered under a Shelf Registration Statement,
their directors, officers, employees or agents and each Person who controls such
underwriter on substantially the same basis as that of the indemnification of
the Initial Purchaser and the selling Holders provided in this Section 7(a). The
Issuers and each Guarantor shall, if requested by any Holder, enter into an
underwriting agreement reflecting such agreement, as provided in Section 5(p)
hereof.

     (b) Each Holder of securities covered by a Registration Statement
(including the Initial Purchaser and, with respect to any Prospectus delivery as
contemplated in Section 5(h) hereof, each Exchanging Dealer) severally and not
jointly agrees to indemnify and hold harmless the Issuers, the Guarantors, the
Initial Purchaser, the director of the Issuers and the Guarantors, the officers
of the Issuers and the Guarantors who signs such Registration Statement and each
Person who controls the Issuers, the Guarantors and the Initial Purchaser within
the meaning of either the Act or the Exchange Act, to the same extent as the
foregoing indemnity from the Issuers and the Guarantors to each such Holder, but
only with reference to written information relating to such Holder furnished to
the Issuers and the Guarantors by or on behalf of such Holder specifically for
inclusion in the documents referred to in the foregoing indemnity. This
indemnity agreement will be in addition to any liability which any such Holder
may otherwise have.

     (c) Promptly after receipt by an indemnified party under this Section 7 or
notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under this
Section, notify the indemnifying party in writing of the commencement thereof;
but the failure so to notify the indemnifying party (i) will not relieve it from
liability under paragraph (a) or (b) above unless and to the extent it did not
otherwise learn of such action and such failure results in the forfeiture by the
indemnifying party of substantial rights and defenses; and (ii) will not, in any
event, relieve the indemnifying party from any obligations to any indemnified
party other than the indemnification obligation provided in paragraph (a) or (b)
above. The indemnifying party shall be entitled to appoint counsel of the
indemnifying party's choice at the indemnifying party's expense to represent the
indemnified party in any action for which indemnification is sought (in which
case the indemnifying party shall not thereafter be responsible for the fees and
expenses of any separate counsel retained by the indemnified party or parties
except as set forth below); provided, however, that such counsel shall be
satisfactory to the indemnified party. Notwithstanding the indemnifying party's
election to appoint counsel to represent the indemnified party in an action, the
indemnified party shall have the right to employ separate counsel (including
local counsel), and the indemnifying party shall bear the reasonable fees, costs
and expenses of such separate counsel if (i) the use of counsel chosen by the
indemnifying party to represent the indemnified party would present such counsel
with a conflict of interest; (ii) the actual or potential defendants

                                       14

<PAGE>

in, or targets of, any such action include both the indemnified party and the
indemnifying party and the indemnified party shall have reasonably concluded
that there may be legal defenses available to it and/or other indemnified
parties which are different from or additional to those available to the
indemnifying party; (iii) the indemnifying party shall not have employed counsel
satisfactory to the indemnified party to represent the indemnified party within
a reasonable time after notice of the institution of such action; or (iv) the
indemnifying party shall authorize the indemnified party to employ separate
counsel at the expense of the indemnifying party. An indemnifying party will
not, without the prior written consent of the indemnified parties, settle or
compromise or consent to the entry of any judgment with respect to any pending
or threatened claim, action, suit or proceeding in respect of which
indemnification or contribution may be sought hereunder (whether or not the
indemnified parties are actual or potential parties to such claim or action)
unless such settlement, compromise or consent includes an unconditional release
of each indemnified party from all liability arising out of such claim, action,
suit or proceeding.

     (d) In the event that the indemnity provided in paragraph (a) or (b) of
this Section is unavailable to or insufficient to hold harmless an indemnified
party for any reason, then each applicable indemnifying party shall have a joint
and several obligation to contribute to the aggregate losses, claims, damages
and liabilities (including legal or other expenses reasonably incurred in
connection with investigating or defending same) (collectively "Losses") to
which such indemnified party may be subject in such proportion as is appropriate
to reflect the relative benefits received by such indemnifying party, on the one
hand, and such indemnified party, on the other hand, from the Initial Placement
and the Registration Statement which resulted in such Losses; provided, however,
that in no case shall the Initial Purchaser or any subsequent Holder of any
Security or New Security be responsible, in the aggregate, for any amount in
excess of the purchase discount or commission applicable to such Security, or in
the case of a New Security, applicable to the Security that was exchangeable
into such New Security, as set forth on the cover page of the Final Memorandum,
nor shall any underwriter be responsible for any amount in excess of the
underwriting discount or commission applicable to the securities purchased by
such underwriter under the Registration Statement which resulted in such Losses.
If the allocation provided by the immediately preceding sentence is unavailable
for any reason, the indemnifying party and the indemnified party shall
contribute in such proportion as is appropriate to reflect not only such
relative benefits but also the relative fault of such indemnifying party, on the
one hand, and such indemnified party, on the other hand, in connection with the
statements or omissions which resulted in such Losses as well as any other
relevant equitable considerations. Benefits received by the Issuers or the
Guarantors shall be deemed to be equal to the sum of (x) the total net proceeds
from the Initial Placement (before deducting expenses) as set forth on the cover
page of the Final Memorandum and (y) the total amount of additional interest
which the Issuers and the Guarantors were not required to pay as a result of
registering the securities covered by the Registration Statement which resulted
in such Losses. Benefits received by the Initial Purchaser shall be deemed to be
equal to the total purchase discounts and commissions as set forth on the cover
page of the Final Memorandum, and benefits received by any other Holders shall
be deemed to be equal to the value of receiving Securities or New Securities, as
applicable, registered under the Act. Benefits received by any underwriter shall
be deemed to be equal to the total underwriting discounts and commissions, as
set forth on the cover page of the Prospectus forming a part of the Registration
Statement which resulted in such Losses. Relative fault shall be determined by
reference to, among other things, whether any alleged untrue statement or
omission relates to information provided by the

                                       15

<PAGE>

indemnifying party, on the one hand, or by the indemnified party, on the other
hand, the intent of the parties and their relative knowledge, access to
information and opportunity to correct or prevent such untrue statement or
omission. The parties agree that it would not be just and equitable if
contribution were determined by pro rata allocation (even if the Holders were
treated as one entity for such purpose) or any other method of allocation which
does not take account of the equitable considerations referred to above.
Notwithstanding the provisions of this paragraph (d), no Person guilty of
fraudulent misrepresentation (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. For purposes of this Section, each Person who
controls a Holder within the meaning of either the Act or the Exchange Act and
each director, officer, employee and agent of such Holder shall have the same
rights to contribution as such Holder, and each Person who controls the Issuers
and the Guarantors within the meaning of either the Act or the Exchange Act,
each officer of the Issuers and the Guarantors who shall have signed the
Registration Statement and each director of the Issuers and the Guarantors shall
have the same rights to contribution as the Issuers and the Guarantors, subject
in each case to the applicable terms and conditions of this paragraph (d).

     (e) The provisions of this Section will remain in full force and effect,
regardless of any investigation made by or on behalf of any Holder or the
Issuers and the Guarantors or any of the officers, directors or controlling
Persons referred to in this Section hereof, and will survive the sale by a
Holder of securities covered by a Registration Statement.

     8. Underwritten Registrations. (a) If any of the Securities or New
Securities, as the case may be, covered by any Shelf Registration Statement are
to be sold in an underwritten offering, the Managing Underwriters shall be
selected by the Majority Holders and shall be reasonably satisfactory to the
Partnership.

     (b) No Person may participate in any underwritten offering pursuant to any
Shelf Registration Statement, unless such Person (i) agrees to sell such
Person's Securities or New Securities, as the case may be, on the basis
reasonably provided in any underwriting arrangements approved by the Persons
entitled hereunder to approve such arrangements; and (ii) completes and executes
all questionnaires, powers of attorney, indemnities, underwriting agreements and
other documents reasonably required under the terms of such underwriting
arrangements.

     9. No Inconsistent Agreements. The Issuers and the Guarantors have not, as
of the date hereof, entered into, nor shall they, on or after the date hereof,
enter into, any agreement with respect to their securities that is inconsistent
with the rights granted to the Holders herein or otherwise conflicts with the
provisions hereof.

     10. Amendments and Waivers. The provisions of this Agreement, including the
provisions of this sentence, may not be amended, qualified, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Issuers and the Guarantors have obtained the

                                       16

<PAGE>

written consent of the Majority Holders (or, after the consummation of any
Registered Exchange Offer in accordance with Section 2 hereof, of New
Securities); provided that, with respect to any matter that directly or
indirectly affects the rights of the Initial Purchaser hereunder, the Issuers
and the Guarantors shall obtain the written consent of the Initial Purchaser
against which such amendment, qualification, supplement, waiver or consent is to
be effective. Notwithstanding the foregoing (except the foregoing proviso), a
waiver or consent to departure from the provisions hereof with respect to a
matter that relates exclusively to the rights of Holders whose Securities or New
Securities, as the case may be, are being sold pursuant to a Registration
Statement and that does not directly or indirectly affect the rights of other
Holders may be given by the Majority Holders, determined on the basis of
Securities or New Securities, as the case may be, being sold rather than
registered under such Registration Statement.

     11. Notices. All notices and other communications provided for or permitted
hereunder shall be made in writing by hand-delivery, first-class mail, telex,
telecopier or air courier guaranteeing overnight delivery:

          (a) if to a Holder, at the most current address given by such holder
     to the Issuers and the Guarantors in accordance with the provisions of this
     Section, which address initially is, with respect to each Holder, the
     address of such Holder maintained by the Registrar under the Indenture,
     with a copy in like manner to UBS Warburg LLC;

          (b) if to you, initially at the respective addresses set forth in the
     Purchase Agreement;

          (c) if to the Issuers, initially at the address set forth in the
     Purchase Agreement; and

          (d) if to the Guarantors, initially at 333 Clay Street, Suite 1600,
     Houston, Texas 77002.

          All such notices and communications shall be deemed to have been duly
     given when received.

          The Initial Purchaser, the Issuers or the Guarantors by notice to the
     other parties may designate additional or different addresses for
     subsequent notices or communications.

     12. Successors and Assigns. This Agreement shall inure to the benefit of
and be binding upon the successors and assigns of each of the parties,
including, without the need for an express assignment or any consent by the
Issuers or the Guarantors thereto, subsequent Holders of Securities and the New
Securities. The Issuers and the Guarantors hereby agree to extend the benefits
of this Agreement to any Holder of Securities and the New Securities, and any
such Holder may specifically enforce the provisions of this Agreement as if an
original party hereto.

                                       17

<PAGE>

     13. Counterparts. This agreement may be in signed counterparts, each of
which shall constitute an original and all of which together shall constitute
one and the same agreement.

     14. Purchases and Sales of Securities. The Issuers and the Guarantors shall
not, and shall use their best efforts to cause their affiliates (as defined in
Rule 405 under the Act) not to, purchase and then resell or otherwise transfer
any Securities for two (2) years, or if a Shelf Registration Statement shall
become effective during such two (2) year period, for the period of such
effectiveness.

     15. Third Party Beneficiaries. Each Holder shall be a third party
beneficiary to the agreements made hereunder between the Issuers and the
Guarantors, on the one hand, and the Initial Purchaser, on the other hand, and
shall have the right to enforce such agreements directly to the extent it deems
such enforcement necessary or advisable to protect its rights or the rights of
other Holders hereunder.

     16. Headings. The headings used herein are for convenience only and shall
not affect the construction hereof.

     17. Applicable Law. 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 in the State of New York.

     18. Severability. In the event that any one of more of the provisions
contained herein, or the application thereof in any circumstances, is held
invalid, illegal or unenforceable in any respect for any reason, the validity,
legality and enforceability of any such provision in every other respect and of
the remaining provisions hereof shall not be in any way impaired or affected
thereby, it being intended that all of the rights and privileges of the parties
shall be enforceable to the fullest extent permitted by law.

     19. Securities Held by the Issuers, the Guarantors, etc. Whenever the
consent or approval of Holders of a specified percentage of principal amount of
Securities or New Securities is required hereunder, Securities or New
Securities, as applicable, held by the Issuers, the Guarantors or their
Affiliates (other than subsequent Holders of Securities or New Securities if
such subsequent Holders are deemed to be Affiliates solely by reason of their
holdings of such Securities or New Securities) shall not be counted in
determining whether such consent or approval was given by the Holders of such
required percentage.

                                       18

<PAGE>

     If the foregoing is in accordance with your understanding of our agreement,
please sign and return to us the enclosed duplicate hereof, whereupon this
letter and your acceptance shall represent a building agreement among the
Issuers, the Guarantors and the several Initial Purchaser.

                             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

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

                             PAA FINANCE CORP.

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

                             PLAINS MARKETING, L.P.

                             By:    PLAINS MARKETING GP INC.
                                    its General Partner

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

                                       19

<PAGE>

                         ALL AMERICAN PIPELINE, L.P.

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

                         PLAINS MARKETING GP INC.

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

                         PLAINS MARKETING CANADA LLC

                         By:    PLAINS MARKETING, L.P.
                                its Sole Member

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

                         PMC (NOVA SCOTIA) COMPANY

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

                                       20

<PAGE>

                         PLAINS MARKETING CANADA, L.P.

                         By: PMC (NOVA SCOTIA) COMPANY
                             its General Partner

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

                         BASIN HOLDINGS GP LLC

                         By:    ALL AMERICAN PIPELINE, L.P.
                                its Sole Member

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

                         BASIN PIPELINE HOLDINGS, L.P.

                         By:    BASIN HOLDINGS GP LLC
                                its General Partner

                         By:    ALL AMERICAN PIPELINE, L.P.
                                its Sole Member

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

                                       21

<PAGE>

                         RANCHO HOLDINGS GP LLC

                         By:    ALL AMERICAN PIPELINE, L.P.
                                its Sole Member

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

                         RANCHO PIPELINE HOLDINGS, L.P.

                         By:    RANCHO HOLDINGS GP LLC
                                its General Partner

                         By:    ALL AMERICAN PIPELINE, L.P.
                                its Sole Member

                         By:    PLAINS MARKETING GP INC.
                                its General Partner

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

The foregoing Agreement is hereby confirmed and accepted as of the date first
above written.

UBS WARBURG LLC

By:         /s/ Michael Jamieson
    -------------------------------------------------
Name:   Michael Jamieson
Title:  Executive Director

By:         /s/ Robert B. Wallace
    -------------------------------------------------
Name:   Robert B. Wallace
Title:  Executive Director

                                       22<PAGE>

                                                                   EXHIBIT 10.37

September 18, 2002

3TEC Energy Corporation
700 Milam Street, Suite 1100
Houston, Texas 77002-8215
Attention: Shane Bayless,
           Vice President-Accounting

Re: Third Restated Credit Agreement among
    3TEC Energy Corporation ("3TEC")
    and Bank One, NA et al. (the "Credit Agreement")

Gentlemen:

You have requested an amendment to the Credit Agreement to extend the Maturity
Date thereof, amend the procedure for determining the Borrowing Base, increase
the Borrowing Base, change the Base Rate Margin and LIBOR Margins and change the
asset sales basket. Specifically, the Credit Agreement is amended in the
following respects:

     (a) Section 1 of the Credit Agreement is hereby amended in the following
respects:

          (i) The definition of "Base Rate Margin" is hereby deleted and the
     following new definition substituted in lieu thereof:

          "Base Rate Margin shall be:

               (i) three-eighths of one percent (.375%) per annum whenever the
          Borrowing Base Usage is equal to or greater than 90%; or

               (ii) one-quarter of one percent (.25%) per annum whenever the
          Borrowing Base Usage is equal to or greater than 66% but less than
          90%; or

               (iii) zero percent (0%) per annum whenever the Borrowing Base
          Usage is less than 66%."

<PAGE>

          (ii) The definition of "LIBOR Margin" is hereby deleted and the
     following new definition substituted in lieu thereof:

          "LIBOR Margin shall be:

               (i) two percent (2%) per annum whenever the Borrowing Base Usage
          is equal to or greater than 90%;

               (ii) one and three-quarters percent (1.75%) per annum whenever
          the Borrowing Base Usage is equal to or greater than 66%, but less
          than 90%;

               (iii) one and one-half percent (1.50%) per annum whenever the
          Borrowing Base Usage is less than 66%."

          (iii) The definition of "Maturity Date" is hereby deleted and the
     following new definition and substituted in lieu thereof:

          "Maturity Date shall mean August 31, 2004."

     (b) Section 7(b) of the Credit Agreement is hereby amended by deleting
therefrom in its entirety the fifth sentence from the end of said Section 7(b)
and substituting the following new sentence in lieu thereof:

         "The redetermined Borrowing Base shall be then determined based upon
         the weighted arithmetic average of the proposed amount submitted by
         each Lender, excluding the highest and lowest Borrowing Base determined
         among the individual Lenders."

     (c) Section 13(a) is hereby amended by deleting Subsection (ii) therefrom
in its entirety and substituting the following in lieu thereof:

          "(ii) sell, lease, transfer or otherwise dispose of, in any fiscal
     year, any of their assets except for (A) sales, leases, transfers or other
     dispositions made in the ordinary course of Borrowers' oil and gas
     businesses, (B) sales, leases or transfers or other dispositions made by
     Borrowers between Borrowing Base Determination Dates which do not exceed an
     aggregate of ten percent (10%) of the then current Borrowing Base in net
     proceeds, and (C) other sales, leases, transfer or other dispositions made
     with the consent of Majority Lenders which are made pursuant to, and in
     full compliance with, Section 12(r) hereof;"

As of the date of this letter amendment, the Borrowing Base shall be
$160,000,000 until redetermined pursuant to the provisions of Section 7(b) of
the Credit Agreement.

The Lenders hereby confirm that they have received notice that ENEX Resources
Corporation merged into 3TEC Energy Corporation effective January 31, 2002, and
3TEC/CRI Corporation merged into 3TEC Energy Corporation effective August 8,
2002.

<PAGE>

Accordingly, the term "Borrowers" as used herein and in the Credit Agreement
shall hereafter mean only 3TEC Energy Corporation.

Except to the extent that its provisions are specifically amended, modified or
superseded by this and by prior amendments thereto, the representations,
warranties and affirmative and negative covenants of the Borrowers contained in
the Credit Agreement are incorporated herein by reference for all purposes as if
copied herein in full. The Borrowers hereby restate and reaffirm each and every
term and provision of the Credit Agreement, as amended, (except to the extent
such terms and provisions relate solely to an earlier date), including, without
limitation, all representations, warranties and affirmative and negative
covenants.

If the foregoing meets with your approval, please execute this letter at the
place indicated below and return an executed copy to the Agent. This Amendment
shall not be effective until it is executed by the Borrowers and by Majority
Lenders (as defined in the Credit Agreement).

                                           Very truly yours,

                                           BANK ONE, NA
                                           Administrative Agent
                                           (Main Office Chicago)

                                           By: /s/ Ronald L. Dierker
                                                   Ronald L. Dierker
RLD/jat                                            Director,Capital Markets

APPROVED THIS 30th DAY
OF SEPTEMBER, 2002

BORROWERS:

3TEC ENERGY CORPORATION
a Delaware corporation

By: /s/ Shane M. Bayless
Name: Shane M. Bayless
Title: VP - Controller & Treasurer

<PAGE>

LENDERS:

BANK ONE, NA
(Main Office Chicago)
as Administrative Agent and as a Lender

By: /s/ Ronald L. Dierker
        Ronald L. Dierker
        Director, Capital Markets

THE BANK OF NOVA SCOTIA

By: /s/ M.D. Smith
Name: M.D. Smith
Title: Agent

UNION BANK OF CALIFORNIA, N.A.

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

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

BMO NESBITT BURNS FINANCING, INC.
as Syndication Agent and a Lender

By: /s/ Cahal B. Carmody
Name: Cahal B. Carmody
Title: Vice President

<PAGE>

WELLS FARGO BANK TEXAS,
NATIONAL ASSOCIATION

By: /s/ Jeff Dalton
Name: Jeff Dalton

CIBC, INC.

By: /s/ Nora Q. Catiis
Name: Nora Q. Catiis
Title: Authorized Signatory

COMERICA BANK-TEXAS

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

FLEET NATIONAL BANK

By: /s/ Daniel S. Schockling
Name: Daniel S. Schockling
Title: Director

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