Document:

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                                                                     EXHIBIT 4.1

                      PLAINS ALL AMERICAN PIPELINE, L.P.,

                               PAA FINANCE CORP.

                                      and

                           FIRST UNION NATIONAL BANK

                                  as Trustee
                             ____________________

                               SENIOR INDENTURE

                             Dated as of _______,

                                DEBT SECURITIES

                                  (UNLIMITED)
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                               TABLE OF CONTENTS

<TABLE>
<S>                                                                                                         <C>
ARTICLE I Definitions....................................................................................    1

   SECTION 1.01.    Certain Terms Defined................................................................    1
   SECTION 1.02.    Other Definitions....................................................................    8
   SECTION 1.03.    Incorporation by Reference of Trust Indenture Act....................................    8
   SECTION 1.04.    Rules of Construction................................................................    8

ARTICLE II Debt Securities...............................................................................    9

   SECTION 2.01.    Forms Generally......................................................................    9
   SECTION 2.02.    Form of Trustee's Certificate of Authentication......................................    9
   SECTION 2.03.    Principal Amount; Issuable in Series.................................................   10
   SECTION 2.04.    Execution of Debt Securities.........................................................   12
   SECTION 2.05.    Authentication and Delivery of Debt Securities.......................................   13
   SECTION 2.06.    Denomination of Debt Securities......................................................   14
   SECTION 2.07.    General Provisions for Registration of Transfer and Exchange.........................   14
   SECTION 2.08.    Temporary Debt Securities............................................................   15
   SECTION 2.09.    Mutilated, Destroyed, Lost or Stolen Debt Securities.................................   16
   SECTION 2.10.    Cancellation of Surrendered Debt Securities..........................................   17
   SECTION 2.11.    Provisions of the Indenture and Debt Securities for the Sole Benefit of the Parties
                    and the Holders......................................................................   17
   SECTION 2.12.    Payment of Interest; Rights Preserved................................................   17
   SECTION 2.13.    Securities Denominated in Foreign Currencies.........................................   17
   SECTION 2.14.    Wire Transfers.......................................................................   18
   SECTION 2.15.    Securities Issuable in the Form of a Global Security.................................   18
   SECTION 2.16.    Medium Term Securities...............................................................   20
   SECTION 2.17.    Defaulted Interest...................................................................   21
   SECTION 2.18.    Judgments............................................................................   21
   SECTION 2.19.    CUSIP Numbers........................................................................   22

ARTICLE III Redemption of Debt Securities................................................................   22

   SECTION 3.01.    Applicability of Article.............................................................   22
   SECTION 3.02.    Notice of Redemption; Selection of Debt Securities...................................   22
   SECTION 3.03.    Payment of Debt Securities Called for Redemption.....................................   24
   SECTION 3.04.    Mandatory and Optional Sinking Funds.................................................   24
   SECTION 3.05.    Redemption of Debt Securities for Sinking Fund.......................................   25

ARTICLE IV Particular Covenants of the Issuers...........................................................   26

   SECTION 4.01.    Payment of Principal of, and Premium, If Any, and Interest on, Debt Securities.......   26
   SECTION 4.02.    Maintenance of Offices or Agencies for Registration of Transfer, Exchange and
                    Payment of Debt Securities...........................................................   27
   SECTION 4.03.    Appointment to Fill a Vacancy in the Office of Trustee...............................   27
   SECTION 4.04.    Duties of Paying Agents, etc.........................................................   27
   SECTION 4.05.    Statement by Officers as to Default..................................................   28
   SECTION 4.06.    Further Instruments and Acts.........................................................   29
   SECTION 4.07.    Corporate, Partnership or Limited Liability Company Existence........................   29
</TABLE>

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<TABLE>
<S>                                                                                                        <C>
   SECTION 4.08.    Maintenance of Properties.............................................................  29
   SECTION 4.09.    Payment of Taxes and Other Claims.....................................................  29
   SECTION 4.10.    Calculation of Original Issue Discount................................................  30
   SECTION 4.11.    Stay, Extension and Usury Laws........................................................  30

ARTICLE V Holders' Lists and Reports by the Issuers and the Trustee.......................................  30

   SECTION 5.01.    Issuers to Furnish Trustee Information as to Names and Addresses of Holders;
                    Preservation of Information...........................................................  30
   SECTION 5.02.    Communications to Holders; Meetings of Holders........................................  31
   SECTION 5.03.    Reports by Issuers....................................................................  31
   SECTION 5.04.    Reports by Trustee....................................................................  32
   SECTION 5.05.    Record Dates for Action by Holders....................................................  32

ARTICLE VI Remedies of the Trustee and Holders in Event of Default........................................  33

   SECTION 6.01.    Events of Default.....................................................................  33
   SECTION 6.02.    Collection of Indebtedness by Trustee, etc............................................  34
   SECTION 6.03.    Application of Moneys Collected by Trustee............................................  35
   SECTION 6.04.    Limitation on Suits by Holders........................................................  36
   SECTION 6.05.    Remedies Cumulative; Delay or Omission in Exercise of Rights Not a Waiver of Default..  37
   SECTION 6.06.    Rights of Holders of Majority in Principal Amount of Debt Securities to Direct
                    Trustee and to Waive Default.............................................. ...........  37
   SECTION 6.07.    Trustee to Give Notice of Defaults Known to It, but May Withhold Such Notice in
                    Certain Circumstances.................................................................  38
   SECTION 6.08.    Requirement of an Undertaking To Pay Costs in Certain Suits under the Indenture or
                    Against the Trustee...................................................................  38

ARTICLE VII Concerning the Trustee........................................................................  38

   SECTION 7.01.    Certain Duties and Responsibilities...................................................  38
   SECTION 7.02.    Certain Rights of Trustee.............................................................  40
   SECTION 7.03.    Trustee Not Liable for Recitals in Indenture or in Debt Securities....................  41
   SECTION 7.04.    Trustee, Paying Agent or Registrar May Own Debt Securities............................  41
   SECTION 7.05.    Moneys Received by Trustee to Be Held in Trust........................................  41
   SECTION 7.06.    Compensation and Reimbursement........................................................  42
   SECTION 7.07.    Right of Trustee to Rely on an Officers' Certificate Where No Other Evidence
                    Specifically Prescribed...............................................................  42
   SECTION 7.08.    Separate Trustee; Replacement of Trustee..............................................  42
   SECTION 7.09.    Successor Trustee by Merger...........................................................  44
   SECTION 7.10.    Eligibility; Disqualification.........................................................  44
   SECTION 7.11.    Preferential Collection of Claims Against Issuers.....................................  44
   SECTION 7.12.    Compliance with Tax Laws..............................................................  44

ARTICLE VIII Concerning the Holders.......................................................................  45

   SECTION 8.01.    Evidence of Action by Holders.........................................................  45
   SECTION 8.02.    Proof of Execution of Instruments and of Holding of Debt Securities...................  45
   SECTION 8.03.    Who May Be Deemed Owner of Debt Securities............................................  45
   SECTION 8.04.    Instruments Executed by Holders Bind Future Holders...................................  45
</TABLE>

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<TABLE>
<S>                                                                                                         <C>
ARTICLE IX Amendment, Supplement and Waiver.............................................................    46

   SECTION 9.01.    Without Consent of Holders of Debt Securities.......................................    46
   SECTION 9.02.    With Consent of Holders of Debt Securities..........................................    47
   SECTION 9.03.    Effect of Supplemental Indentures...................................................    49
   SECTION 9.04.    Debt Securities May Bear Notation of Changes by Supplemental Indentures.............    49

ARTICLE X Consolidation, Merger, Sale or Conveyance.....................................................    49

   SECTION 10.01.   Consolidations and Mergers of the Issuers...........................................    49
   SECTION 10.02.   Rights and Duties of Successor Company..............................................    50

ARTICLE XI Satisfaction and Discharge of Indenture; Unclaimed Moneys....................................    50

   SECTION 11.01.   Satisfaction and Discharge; Application of Trust Money..............................    50
   SECTION 11.02.   Repayment to Issuers................................................................    52
   SECTION 11.03.   Indemnity for U.S. Government Obligations...........................................    52
   SECTION 11.04.   Reinstatement.......................................................................    52

ARTICLE XII Miscellaneous Provisions....................................................................    52

   SECTION 12.01.   Successors and Assigns of Issuers Bound by Indenture................................    52
   SECTION 12.02.   Acts of Board, Committee or Officer of Successor Company Valid......................    52
   SECTION 12.03.   Required Notices or Demands.........................................................    53
   SECTION 12.04.   Indenture and Debt Securities to Be Construed in Accordance with the Laws of the
                    State of New York...................................................................    53
   SECTION 12.05.   Officers' Certificate and Opinion of Counsel to Be Furnished upon Application or
                    Demand by the Issuers...............................................................    53
   SECTION 12.06.   Payments Due on Legal Holidays......................................................    54
   SECTION 12.07.   Provisions Required by Trust Indenture Act to Control...............................    54
   SECTION 12.08.   Computation of Interest on Debt Securities..........................................    54
   SECTION 12.09.   Rules by Trustee, Paying Agent and Registrar........................................    54
   SECTION 12.10.   No Recourse Against Others..........................................................    54
   SECTION 12.11.   Severability........................................................................    54
   SECTION 12.12.   Effect of Headings..................................................................    55
   SECTION 12.13.   Indenture May Be Executed in Counterparts...........................................    55
</TABLE>

                                      iii
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                             CROSS-REFERENCE TABLE

<TABLE>
<CAPTION>
     Trust Indenture
       Act Section                                                                           Indenture Section
       -----------                                                                           -----------------
<S>                                                                                          <C>
310(a)(1)...............................................................................                  7.10
(a)(2)..................................................................................                  7.10
(a)(3)..................................................................................                    N/A
(a)(4)..................................................................................                    N/A
(a)(5)..................................................................................                   7.10
(b).....................................................................................                   7.10
(c).....................................................................................                    N/A
311(a)..................................................................................                   7.11
(b).....................................................................................                   7.11
(c).....................................................................................                    N/A
312(a)..................................................................................                   5.01
(b).....................................................................................                   5.02
(c).....................................................................................                   5.02
313(a)..................................................................................                   5.04
(b)(1)..................................................................................                   5.04
(b)(2)..................................................................................                   5.04
(c).....................................................................................            5.04; 12.03
(d).....................................................................................                   5.04
314(a)..................................................................................            5.03; 12.03
(b).....................................................................................                    N/A
(c)(1)..................................................................................                  12.05
(c)(2)..................................................................................                  12.05
(c)(3)..................................................................................                    N/A
(d).....................................................................................                    N/A
(e).....................................................................................                  12.05
(f).....................................................................................                    N/A
315(a)..................................................................................                   7.01
(b).....................................................................................            6.07; 12.03
(c) ....................................................................................                   7.01
(d).....................................................................................                   7.01
(e).....................................................................................                   6.03
316(a)(last sentence)...................................................................                   1.01
(a)(1)(A)...............................................................................                   6.06
(a)(1)(B)...............................................................................                   6.06
(a)(2)..................................................................................                    N/A
(b).....................................................................................                   6.04
(c).....................................................................................                   2.17
317(a)(1)...............................................................................                   6.02
(a)(2)..................................................................................                   6.09
(b).....................................................................................                    404
318(a)..................................................................................                  12.07
(b).....................................................................................                    N/A
</TABLE>

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<TABLE>
<S>                                                                                                       <C>
(c).....................................................................................                  12.07
</TABLE>

__________________
N/A means not applicable.

                                       v
<PAGE>

                  THIS SENIOR INDENTURE dated as of ______, is among 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 FIRST UNION NATIONAL BANK, a national banking
association (the "Trustee").

                                   WITNESSETH:

                  WHEREAS, Plains All American GP LLC, a Delaware limited
liability company (the "Managing General Partner"), as general partner of Plains
AAP, L.P., a Delaware limited partnership (the "General Partner") and the
general partner of the Partnership, and PAA Finance have duly authorized the
execution and delivery of the Indenture to provide for the issuance from time to
time of their debentures, notes, bonds or other evidences of indebtedness to be
issued in one or more series in an unlimited aggregate principal amount (herein
called the "Debt Securities"), as in the Indenture provided.

                  WHEREAS, all things necessary to make the Indenture a valid
agreement of the Issuers, in accordance with its terms, have been done.

                  NOW, THEREFORE, in consideration of the agreements and
obligations set forth herein and for good and valuable consideration, the
sufficiency of which is hereby acknowledged, the Issuers and the Trustee hereby
agree with each other, for the equal and proportionate benefit of the respective
Holders from time to time of the Debt Securities or any series thereof, as
follows:

                                   ARTICLE I

                                  Definitions
                                  -----------

                  SECTION 1.01.     Certain Terms Defined. The terms defined in
                                    ---------------------
this Section 1.01 (except as herein otherwise expressly provided or unless the
context otherwise requires) for all purposes of the Indenture and of any
Indenture supplemental hereto shall have the respective meanings specified in
this Section 1.01. All other terms used in the Indenture which are defined in
the Trust Indenture Act or which are by reference therein defined in the
Securities Act (except as herein otherwise expressly provided or unless the
context otherwise requires), shall have the meanings assigned to such terms in
the Trust Indenture Act and in the Securities Act as in force as of the date of
original execution of the Indenture.

                  "Bankruptcy Law" means Title 11, U.S. Code or any similar
                   --------------
federal or state law for the relief of debtors.

                  "Board of Directors" means (a) with respect to the
                   ------------------
Partnership, the board of directors of the Managing General Partner, and (b)
with respect to PAA Finance, its board of directors, or, in each case, with
respect to any determination or resolution required or permitted to be made
hereunder, any duly authorized committee or subcommittee of such board. All
references in the Indenture to "Board of Directors" shall be deemed to refer to
the Board of Directors of the Partnership, unless otherwise expressly indicated
or the context otherwise requires.

                                       1
<PAGE>

                  "Board Resolution" means a copy of a resolution certified by
                   ----------------
the appropriate person to have been duly adopted by the Board of Directors and
to be in full force and effect on the date of such certification.

                  "Business Day" means each Monday, Tuesday, Wednesday, Thursday
                   ------------
and Friday which is not a day on which banking institutions in Houston, Texas,
the Borough of Manhattan, the City of New York, New York, or the city in which
the Corporate Trust Office of the Trustee is located, are authorized or
obligated by law or executive order to close.

                  "Code" means the Internal Revenue Code of 1986, as amended
                   ----
from time to time and any successor statute.

                  "Commission" means the Securities and Exchange Commission, as
                   ----------
from time to time constituted, created under the Exchange Act, or, if at any
time after the execution of the Indenture such Commission is not existing and
performing the duties now assigned to it under the Trust Indenture Act, then the
body performing such duties at such time.

                  "Corporate Trust Office of the Trustee" means the principal
                   -------------------------------------
corporate trust office of the Trustee, at which at any particular time its
corporate trust business shall be administered, which office at the date of
execution of the Indenture is located at 1525 West W.T. Harris Blvd-3C3,
Charlotte, North Carolina 28288-1153, Attention: Corporate Trust Operations.

                  "Currency" means Dollars or Foreign Currency.
                   --------

                  "Debt Security" or "Debt Securities" has the meaning stated in
                   -------------      ---------------
the first recital of the Indenture and more particularly means any debt security
or debt securities, as the case may be, of any series authenticated and
delivered under the Indenture.

                  "Default" means any event that is, or with the passage of time
                   -------
or the giving of notice or both would be, an Event of Default.

                  "Depositary" means, unless otherwise specified by the Issuers
                   ----------
pursuant to either Section 2.03 or 2.15, with respect to registered Debt
Securities of any series issuable or issued in whole or in part in the form of
one or more Global Securities, The Depository Trust Company, New York, New York,
or any successor thereto registered as a clearing agency under the Exchange Act
or other applicable statute or regulations.

                  "Dollar" or "$" means such currency of the United States as at
                   ------      -
the time of payment is legal tender for the payment of public and private debts.

                  "Dollar Equivalent" means, with respect to any monetary amount
                   -----------------
in a Foreign Currency, at any time for the determination thereof, the amount of
Dollars obtained by converting such Foreign Currency involved in such
computation into Dollars at the spot rate for the purchase of Dollars with the
applicable Foreign Currency as quoted by Citibank, N.A. (unless another
comparable financial institution is designated by the Issuers) in New York, New
York at approximately 11:00 a.m. (New York time) on the date two business days
prior to such determination.

                                       2
<PAGE>

                  "Equity Interests" means:
                   ----------------

                  (1)      in the case of a corporation, corporate stock;

                  (2)      in the case of an association or a business entity,
any and all shares, interests, participations, rights or other equivalents
(however designated) of corporate stock;

                  (3)      in the case of a partnership or limited liability
company, partnership or membership interests (whether general or limited);

                  (4)      any other interest or participation that confers on a
Person the right to receive a share of the profits and losses of, or
distributions of assets of, the issuing Person; and

                  (5)      all warrants, options or other rights to acquire any
of the interests described in clauses (1) through (4) above (but excluding any
debt security that is convertible into, or exchangeable for, any of the
interests described in clauses (1) through (4) above).

                  "Event of Default" has the meaning specified in Section 6.01.
                   ----------------

                  "Exchange Act" means the Securities Exchange Act of 1934, as
                   ------------
amended, or any successor statute.

                  "Floating Rate Security" means a Debt Security that provides
                   ----------------------
for the payment of interest at a variable rate determined periodically by
reference to an interest rate index specified pursuant to Section 2.03.

                  "Foreign Currency" means a currency issued or adopted by the
                   ----------------
government of any country other than the United States or a composite currency
the value of which is determined by reference to the values of the currencies of
any group of countries.

                  "GAAP" means United States generally accepted accounting
                   ----
principles set forth in the opinions and pronouncements of the Accounting
Principles Board of the American Institute of Certified Public Accountants and
statements and pronouncements of the Financial Accounting Standards Board or in
such other statements by such other entity as have been approved by a
significant segment of the accounting profession, which are in effect from time
to time.

                  "General Partner" means Plains AAP, L.P., a Delaware limited
                   ---------------
liability company, and its successors and permitted assigns as general partner
of the Partnership.

                  "Global Security" means with respect to any series of Debt
                   ---------------
Securities issued hereunder, a Debt Security that is executed by the Issuers and
authenticated and delivered by the Trustee to the Depositary or pursuant to the
Depositary's instruction, all in accordance with the Indenture, or the
applicable Board Resolution and set forth in an Officers' Certificate, which
shall be registered in the name of the Depositary or its nominee and which shall
represent, and shall be denominated in an amount equal to the aggregate
principal amount of, all the Outstanding Debt Securities of such series or any
portion thereof, in either case having the same

                                       3
<PAGE>

terms, including, without limitation, the same original issue date, date or
dates on which principal is due and interest rate or method of determining
interest.

                  "Holder," "Holder of Debt Securities" or other similar terms
                   ------    -------------------------
mean, with respect to a Registered Security, the Registered Holder.

                  "Indenture" means this instrument as originally executed, or,
                   ---------
if amended or supplemented as herein provided, as so amended or supplemented,
and shall include the form and terms of particular series of Debt Securities as
contemplated hereunder, whether or not a supplemental Indenture is entered into
with respect thereto.

                  "Issuer Order" means a written order of the Issuers, signed by
                   ------------
the Chairman of the Board, President or any Vice President of each of the
Managing General Partner and PAA Finance and by the Treasurer, Secretary, any
Assistant Treasurer or any Assistant Secretary of each of the Managing General
Partner and PAA Finance.

                  "Issuers" means the Partnership and PAA Finance, and, subject
                   -------
to the provisions of Article X, shall also include their successors and
permitted assigns.

                  "Lien" means, with respect to any asset, any mortgage, lien
                   ----
(statutory or otherwise), pledge, charge, security interest, hypothecation,
assignment for security, claim, preference, priority or encumbrance of any kind
in respect of such asset, whether or not filed, recorded or otherwise perfected
under applicable law, including any conditional sale or other title retention
agreement or any lease in the nature thereof, any option or other agreement to
grant a security interest in and any filing of or agreement to give any
financing statement under the Uniform Commercial Code (or equivalent statute) of
any jurisdiction, other than a precautionary financing statement respecting a
lease not intended as a security agreement.

                  "Managing General Partner" means Plains All American GP LLC, a
                   ------------------------
Delaware limited liability company and its successors and permitted assigns as
the general partner of the General Partner or as the business entity with the
ultimate authority to manage the business and operations of the Partnership.

                  "Officers' Certificate" means a certificate signed by the
                   ---------------------
Chairman of the Board of Directors, President or any Vice President of each of
the Managing General Partner and PAA Finance and by the Treasurer, Secretary,
any Assistant Treasurer or any Assistant Secretary of each of the Managing
General Partner and PAA Finance. Each such certificate shall include the
statements provided for in Section 12.05, if applicable.

                  "Opinion of Counsel" means an opinion in writing signed by
                   ------------------
legal counsel for the Issuers (which counsel may be an employee of the Issuers
or outside counsel for the Issuers). Each such opinion shall include the
statements provided for in Section 12.05, if applicable.

                  "Original Issue Discount Debt Security" means any Debt
                   -------------------------------------
Security which provides for an amount less than the principal amount thereof to
be due and payable upon a declaration or acceleration of the maturity thereof
pursuant to Section 6.01.

                                       4
<PAGE>

                  "Outstanding" when used with respect to any series of Debt
                   -----------
Securities, means, as of the date of determination, all Debt Securities of that
series theretofore authenticated and delivered under the Indenture, except:

                           (1)  Debt Securities of that series theretofore
                  canceled by the Trustee or delivered to the Trustee for
                  cancellation;

                           (2)  Debt Securities of that series for whose payment
                  or redemption money in the necessary amount has been
                  theretofore deposited with the Trustee or any paying agent
                  (other than the Partnership or PAA Finance) in trust or set
                  aside and segregated in trust by the Issuers (if either of the
                  Issuers shall act as its own paying agent) for the holders of
                  such Debt Securities; provided, that, if such Debt Securities
                                        --------
                  are to be redeemed, notice of such redemption has been duly
                  given pursuant to the Indenture or provision therefor
                  satisfactory to the Trustee has been made; and

                           (3)  Debt Securities of that series which have been
                  paid pursuant to Section 2.09 or in exchange for or in lieu of
                  which other Debt Securities have been authenticated and
                  delivered pursuant to the Indenture, other than any such Debt
                  Securities in respect of which there shall have been presented
                  to the Trustee proof satisfactory to it that such Debt
                  Securities are held by a bona fide purchaser in whose hands
                  such Debt Securities are valid obligations of the Issuers;

provided, however, that in determining whether the Holders of the requisite
--------  -------
principal amount of the Outstanding Debt Securities of any series have given any
request, demand, authorization, direction, notice, consent or waiver hereunder,
Debt Securities owned by the Issuers or any other obligor upon the Debt
Securities or any Subsidiary of the Issuers or of such other obligor shall be
disregarded and deemed not to be Outstanding, except that, in determining
whether the Trustee shall be protected in relying upon any such request, demand,
authorization, direction, notice, consent or waiver, only Debt Securities which
a Responsible Officer of the Trustee actually knows to be so owned shall be so
disregarded. Debt Securities so owned which have been pledged in good faith may
be regarded as Outstanding if the pledgee establishes to the satisfaction of the
Trustee the pledgee's right so to act with respect to such Debt Securities and
that the pledgee is not one of the Issuers or any other obligor upon the Debt
Securities or a Subsidiary of the Issuers or of such other obligor. In
determining whether the Holders of the requisite principal amount of outstanding
Debt Securities have given any request, demand, authorization, direction,
notice, consent or waiver hereunder, the principal amount of an Original Issue
Discount Debt Security that shall be deemed to be Outstanding for such purposes
shall be the amount of the principal thereof that would be due and payable as of
the date of such determination upon a declaration of acceleration of the
maturity thereof pursuant to Section 6.01. In determining whether the Holders of
the requisite principal amount of the Outstanding Debt Securities of any series
have given any request, demand, authorization, direction, notice, consent or
waiver hereunder, the principal amount of a Debt Security denominated in one or
more Foreign Currencies or currency units that shall be deemed to be Outstanding
for such purposes shall be the Dollar Equivalent, determined in the manner
provided as contemplated by Section 2.03 on the date of original issuance of
such Debt Security, of the principal amount (or, in the case of any Original
Issue Discount Security, the Dollar Equivalent on the date of original

                                       5
<PAGE>

issuance of such Security of the amount determined as provided in the preceding
sentence above) of such Debt Security.

                  "PAA Finance" means PAA Finance Corp., a Delaware corporation,
                   -----------
and, subject to the provisions of Article X, shall also include its successors
and assigns.

                  "Partnership" means Plains All American Pipeline, L.P., a
                   -----------
Delaware limited partnership, and, subject to the provisions of Article X, shall
also include its successors and assigns.

                  "Payment Blockage Period" has the meaning set forth in Section
                   -----------------------
13.03.

                  "Person" means any individual, corporation, partnership, joint
                   ------
venture, association, limited liability company, joint stock company, trust,
unincorporated organization, government or any agency or political subdivision
thereof or any other entity.

                  "Place of Payment" means, when used with respect to the Debt
                   ----------------
Securities of any series, the place or places where the principal of, and
premium, if any, and interest on, the Debt Securities of that series are payable
as specified pursuant to Section 2.03.

                  "Registered Holder" means the Person in whose name a
                   -----------------
Registered Security is registered in the Debt Security Register (as defined in
Section 2.07(a)).

                  "Registered Security" means any Debt Security registered as to
                   -------------------
principal and interest in the Debt Security Register (as defined in Section
2.07(a)).

                  "Registrar" has the meaning set forth in Section 2.07(a).
                   ---------

                  "Responsible Officer" when used with respect to the Trustee,
                   -------------------
means any officer within the Corporate Trust Office of the Trustee or any other
officer of the Trustee performing functions similar to those performed by the
persons who at the time shall be such officers, and any other officer of the
Trustee to whom corporate trust matters are referred because of his knowledge of
and familiarity with the particular subject.

                  "Securities Act" means the Securities Act of 1933, as amended,
                   --------------
or any successor statute.

                  "Stated Maturity" means, at any time, with respect to any
                   ---------------
installment of interest or principal on any series of Debt Securities, the date
on which such payment of interest or principal was scheduled to be paid in the
original documentation governing such indebtedness or such later date as such
documentation shall provide at that time, and shall not include any contingent
obligations to repay, redeem or repurchase any such interest or principal prior
to the date originally scheduled for the payment thereof.

                                       6
<PAGE>

                  "Subsidiary" means, with respect to any Person:
                   ----------

                  (1) any corporation, association or other business entity of
which more than 50% of the Voting Stock is at the time owned or controlled,
directly or indirectly, by such Person or one or more of the other Subsidiaries
of that Person (or a combination thereof); and

                  (2) any partnership (whether general or limited) or limited
liability company (a) the sole general partner or the managing general partner
or managing member of which is such Person or a Subsidiary of such Person, or
(b) if there are more than a single general partner or member, either (i) the
only general partners or managing members of which are such Person and/or one or
more Subsidiaries of such Person (or any combination thereof) or (ii) such
Person owns or controls, directly or indirectly, a majority of the outstanding
general partner interests, member interests or other Voting Stock of such
partnership or limited liability company, respectively.

                  "Trust Indenture Act" (except as herein otherwise expressly
                   -------------------
provided) means the Trust Indenture Act of 1939 as in force at the date of the
Indenture as originally executed and, to the extent required by law, as amended,
or any successor statute.

                  "Trustee" initially means First Union National Bank and any
                   -------
other Person or Persons appointed as such from time to time pursuant to Section
7.08, and, subject to the provisions of Article VII, includes its or their
successors and assigns. If at any time there is more than one such Person,
"Trustee" as used with respect to the Debt Securities of any series shall mean
the Trustee with respect to the Debt Securities of that series.

                  "United States" means the United States of America (including
                   -------------
the States and the District of Columbia), its territories, its possessions and
other areas subject to its jurisdiction.

                  "U.S. Government Obligations" means securities that are (i)
                   ---------------------------
direct obligations of the United States for the payment of which its full faith
and credit is pledged; (ii) obligations of a Person controlled or supervised by
and acting as an agency or instrumentality of the United States, the payment of
which is unconditionally guaranteed as a full faith and credit obligation by the
United States, which, in either case, under clause (i) or (ii) above, are not
callable or redeemable at the option of the issuers thereof; or (iii) depository
receipts issued by a bank or trust company as custodian with respect to any such
U.S. Government Obligations or a specific payment of interest on or principal of
any such U.S. Government Obligation held by such custodian for the account of
the holder of a depository receipt, provided that (except as required by law)
such custodian is not authorized to make any deduction from the amount payable
to the holder of such depository receipt from any amount received by the
custodian in respect of the U.S. Government Obligation evidenced by such
depository receipt.

                  "Voting Stock" of any Person as of any date means the Equity
                   ------------
Interests of such Person pursuant to which the holders thereof have the general
voting power under ordinary circumstances to elect at least a majority of the
board of directors, managers, general partners or trustees of any Person
(regardless of whether, at the time, Equity Interests of any other class or
classes shall have, or might have, voting power by reason of the occurrence of
any contingency)

                                       7
<PAGE>

or, with respect to a partnership (whether general or limited), any general
partner interest in such partnership.

                  "Yield to Maturity" means the yield to maturity calculated at
                   -----------------
the time of issuance of a series of Debt Securities, or, if applicable, at the
most recent redetermination of interest on such series and calculated in
accordance with accepted financial practice.

                  SECTION 1.02.     Other Definitions.
                                    -----------------

Term                                                Section in which Defined
----                                                ------------------------

"Debt Security Register                                        2.07

"Defaulted Interest"                                           2.17

"Designated Currency"                                          2.18

"mandatory sinking fund payment"                               3.04

"optional sinking fund payment"                                3.04

"Successor Company"                                           10.01

                  SECTION 1.03.     Incorporation by Reference of Trust
                                    -----------------------------------
Indenture Act. The Indenture is subject to the mandatory provisions of the Trust
-------------
Indenture Act which are incorporated by reference in and made a part of the
Indenture. The following Trust Indenture Act terms have the following meanings:

                  "indenture securities" means the Debt Securities,
                   --------------------

                  "indenture security holder" means a Holder,
                   -------------------------

                  "indenture to be qualified" means the Indenture,
                   -------------------------

                  "indenture trustee" or "institutional trustee" means the
                   -----------------      ---------------------
Trustee and

                  "obligor" on the indenture securities means the Issuers and
                   -------
any other obligor on the Debt Securities.

                  All other Trust Indenture Act terms used in the Indenture that
are defined by the Trust Indenture Act, reference to another statute or defined
by rules of the Commission have the meanings assigned to them by such
definitions.

                  SECTION 1.04.     Rules of Construction. Unless the context
                                    ---------------------
otherwise requires:

                  (1)      a term has the meaning assigned to it;

                  (2)      an accounting term not otherwise defined has the
meaning assigned to it in accordance with GAAP;

                                       8
<PAGE>

                  (3)      "or" is not exclusive;

                  (4)      "including" means including without limitation; and

                  (5)      words in the singular include the plural and words in
          the plural include the singular.

                                  ARTICLE II

                                Debt Securities
                                ---------------

                  SECTION 2.01.     Forms Generally. The Debt Securities of each
                                    ---------------
series shall be in substantially the form established without the approval of
any Holder by or pursuant to a Board Resolution of each of the Issuers or in one
or more Indentures supplemental hereto, in each case with such appropriate
insertions, omissions, substitutions and other variations as are required or
permitted by the Indenture, and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as the Issuers
may deem appropriate (and, if not contained in a supplemental Indenture entered
into in accordance with Article IX, as are not prohibited by the provisions of
the Indenture) or as may be required or appropriate to comply with any law or
with any rules made pursuant thereto or with any rules of any securities
exchange on which such series of Debt Securities may be listed, or to conform to
general usage, or as may, consistently herewith, be determined by the officers
executing such Debt Securities as evidenced by their execution of the Debt
Securities.

                  The definitive Debt Securities of each series shall be
printed, lithographed or engraved on steel engraved borders or may be produced
in any other manner, all as determined by the officers executing such Debt
Securities, as evidenced by their execution of such Debt Securities.

                  SECTION 2.02.     Form of Trustee's Certificate of
                                    --------------------------------
Authentication. The Trustee's Certificate of Authentication on all Debt
--------------
Securities authenticated by the Trustee shall be in substantially the following
form:

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

                  This is one of the Debt Securities of the series designated
therein referred to in the within-mentioned Indenture.

                                             ________________________________,
                                             as Trustee

                                             By _____________________________
                                                     Authorized Signatory

                                             Dated:__________________________

                                       9
<PAGE>

                  SECTION 2.03.     Principal Amount; Issuable in Series. The
                                    ------------------------------------
aggregate principal amount of Debt Securities which may be issued, executed,
authenticated, delivered and outstanding under the Indenture is unlimited.

                  The Debt Securities may be issued in one or more series. There
shall be established, without the approval of any Holders, in or pursuant to a
Board Resolution of each of the Issuers and set forth in an Officers'
Certificate of each of the Issuers, or established in one or more Indentures
supplemental hereto, prior to the issuance of Debt Securities of any series any
or all of the following:

                  (1)      the title of the Debt Securities of the series (which
         shall distinguish the Debt Securities of the series from all other Debt
         Securities);

                  (2)      any limit upon the aggregate principal amount of the
         Debt Securities of the series which may be authenticated and delivered
         under the Indenture (except for Debt Securities authenticated and
         delivered upon registration of transfer of, or in exchange for, or in
         lieu of, other Debt Securities of the series pursuant to this Article
         II);

                  (3)      the date or dates on which the principal and premium,
         if any, of the Debt Securities of the series are payable;

                  (4)      the rate or rates (which may be fixed or variable) at
         which the Debt Securities of the series shall bear interest, if any, or
         the method of determining such rate or rates, the date or dates from
         which such interest shall accrue, the interest payment dates on which
         such interest shall be payable, or the method by which such date will
         be determined, and in the case of Registered Securities, the record
         dates for the determination of Holders thereof to whom such interest is
         payable; and the basis upon which interest will be calculated if other
         than that of a 360-day year of twelve thirty-day months;

                  (5)      the Place or Places of Payment, if any, in addition
         to or instead of the Corporate Trust Office of the Trustee where the
         principal of, and interest on, Debt Securities of the series shall be
         payable;

                  (6)      the price or prices at which, the period or periods
         within which and the terms and conditions upon which Debt Securities of
         the series may be redeemed, in whole or in part, at the option of the
         Issuers or otherwise;

                  (7)      the obligation, if any, of the Issuers to redeem,
         purchase or repay Debt Securities of the series pursuant to any sinking
         fund or analogous provisions or at the option of a Holder thereof, and
         the price or prices at which and the period or periods within which and
         the terms and conditions upon which Debt Securities of the series shall
         be redeemed, purchased or repaid, in whole or in part, pursuant to such
         obligations;

                  (8)      the terms, if any, upon which the Debt Securities of
         the series may be convertible into or exchanged for Equity Interests,
         other Debt Securities or other securities of any kind of the
         Partnership, PAA Finance or any other obligor or issuer and the terms
         and conditions upon which such conversion or exchange shall be
         effected,

                                       10
<PAGE>

     including the initial conversion or exchange price or rate, the conversion
     or exchange period and any other provision in addition to or in lieu of
     those described herein;

          (9)   if other than denominations of $1,000 and any integral multiple
     thereof, the denominations in which Debt Securities of the series shall be
     issuable;

          (10)  if the amount of principal of or any premium or interest on Debt
     Securities of the series may be determined with reference to an index or
     pursuant to a formula, the manner in which such amounts will be determined;

          (11)  if the principal amount payable at the Stated Maturity of Debt
     Securities of the series will not be determinable as of any one or more
     dates prior to such Stated Maturity, the amount which will be deemed to be
     such principal amount as of any such date for any purpose, including the
     principal amount thereof which will be due and payable upon any maturity
     other than the Stated Maturity or which will be deemed to be Outstanding as
     of any such date (or, in any such case, the manner in which such deemed
     principal amount is to be determined); and the manner of determining the
     equivalent thereof in the currency of the United States of America for
     purposes of the definition of Dollar Equivalent;

          (12)  any changes or additions to Article XI;

          (13)  if other than Dollars, the coin or Currency or Currencies or
     units of two or more Currencies in which payment of the principal of and
     premium, if any, and interest on, Debt Securities of the series shall be
     payable;

          (14)  if other than the principal amount thereof, the portion of the
     principal amount of Debt Securities of the series which shall be payable
     upon declaration of acceleration of the maturity thereof pursuant to
     Section 6.01 or provable in bankruptcy pursuant to Section 6.02;

          (15)  the terms, if any, of the transfer, mortgage, pledge or
     assignment as security for the Debt Securities of the series of any
     properties, assets, moneys, proceeds, securities or other collateral,
     including whether certain provisions of the Trust Indenture Act are
     applicable and any corresponding changes to provisions of the Indenture as
     currently in effect;

          (16)  any addition to or change in the Events of Default with respect
     to the Debt Securities of the series and any change in the right of the
     Trustee or the Holders to declare the principal of and interest on, such
     Debt Securities due and payable;

          (17)  if the Debt Securities of the series shall be issued in whole or
     in part in the form of a Global Security or Securities, the terms and
     conditions, if any, upon which such Global Security or Securities may be
     exchanged in whole or in part for other individual Debt Securities in
     definitive registered form; and the Depositary for such Global Security or
     Securities and the form of any legend or legends to be borne by any such
     Global Security or Securities in addition to or in lieu of the legend
     referred to in Section 2.15;

                                       11
<PAGE>

          (18)  any trustees, authenticating or paying agents, transfer agents
     or registrars;

          (19)  the applicability of, and any addition to or change in the
     covenants and definitions currently set forth in the Indenture or in the
     terms currently set forth in Article X, including conditioning any merger,
     conveyance, transfer or lease permitted by Article X upon the satisfaction
     of an indebtedness coverage standard by the Issuers and any Successor
     Company (as defined in Article X);

          (20)  the terms, if any, of any guarantee of the payment of principal
     of, and premium, if any, and interest on, Debt Securities of the series and
     any corresponding changes to the provisions of the Indenture as currently
     in effect;

          (21)  with regard to Debt Securities of the series that do not bear
     interest, the dates for certain required reports to the Trustee;

          (22)  any other terms of the Debt Securities of the series (which
     terms shall not be prohibited by the provisions of the Indenture); and

          (23)  applicable CUSIP Numbers.

          All Debt Securities of any one series appertaining thereto shall be
substantially identical except as to denomination and except as may otherwise be
provided in or pursuant to such Board Resolutions and as set forth in such
Officers' Certificates or in any such Indenture supplemental hereto.

          SECTION 2.04.  Execution of Debt Securities. The Debt Securities shall
                         ----------------------------
be signed on behalf of the Partnership by the Chairman of the Board, the
President or a Vice President of the Managing General Partner, and shall be
signed on behalf of PAA Finance by its Chairman of the Board, its President or a
Vice President. Such signatures upon the Debt Securities may be the manual or
facsimile signatures of the present or any future such authorized officers and
may be imprinted or otherwise reproduced on the Debt Securities. The seals of
the Issuers, if any, may be in the form of a facsimile thereof and may be
impressed, affixed, imprinted or otherwise reproduced on the Debt Securities.

          Only such Debt Securities as shall bear thereon a certificate of
authentication substantially in the form hereinbefore recited, signed manually
by the Trustee, shall be entitled to the benefits of the Indenture or be valid
or obligatory for any purpose. Such certificate by the Trustee upon any Debt
Security executed by the Issuers shall be conclusive evidence that the Debt
Security so authenticated has been duly authenticated and delivered hereunder.

          In case any officer of either of the Managing General Partner or PAA
Finance who shall have signed any of the Debt Securities shall cease to be such
officer before the Debt Securities so signed shall have been authenticated and
delivered by the Trustee, or disposed of by the Issuers, such Debt Securities
nevertheless may be authenticated and delivered or disposed of as though the
Person who signed such Debt Securities had not ceased to be such officer of the
Managing General Partner or PAA Finance; and any Debt Security may be signed on
behalf of the Issuers by such Persons as, at the actual date of the execution of
such Debt Security, shall be the proper officers of the Managing General Partner
or PAA Finance, as applicable, although at

                                       12
<PAGE>

the date of such Debt Security or of the execution of the Indenture any such
Person was not such officer.

          SECTION 2.05.  Authentication and Delivery of Debt Securities. At any
                         ----------------------------------------------
time and from time to time after the execution and delivery of the Indenture,
the Issuers may deliver Debt Securities of any series executed by the Issuers to
the Trustee for authentication, and the Trustee shall thereupon authenticate and
deliver said Debt Securities to or upon an Issuer Order. The Debt Securities
shall be dated the date of their authentication. In authenticating such Debt
Securities and accepting the additional responsibilities under the Indenture in
relation to such Debt Securities, the Trustee shall be entitled to receive, and
(subject to Section 7.01) shall be fully protected in relying upon:

          (1)  a copy of any Board Resolution of each of the Issuers, certified
     by the Secretary or Assistant Secretary of each of the Issuers, authorizing
     the terms of issuance of any series of Debt Securities;

          (2)  an executed supplemental Indenture, if any;

          (3)  an Officers' Certificate; and

          (4)  an Opinion of Counsel prepared in accordance with Section 12.05
     substantially to the effect that:

               (a)  the form of such Debt Securities has been established by or
          pursuant to a Board Resolution of each of the Issuers or by a
          supplemental Indenture as permitted by Section 2.01 in conformity with
          the provisions of the Indenture;

               (b)  the terms of such Debt Securities have been established by
          or pursuant to a Board Resolution of each of the Issuers or by a
          supplemental Indenture as permitted by Section 2.03 in conformity with
          the provisions of the Indenture; and

               (c)  such Debt Securities, when authenticated and delivered by
          the Trustee and issued by the Issuers in the manner and subject to any
          conditions specified in such Opinion of Counsel, will constitute valid
          and legally binding obligations of the Issuers, enforceable in
          accordance with their terms except as (i) the enforceability thereof
          may be limited by bankruptcy, insolvency or similar laws affecting the
          enforcement of creditors' rights generally and (ii) rights of
          acceleration and the availability of equitable remedies may be limited
          by equitable principles of general applicability.

          Such Opinion of Counsel need express no opinion as to whether a court
in the United States would render a money judgment in a Currency other than
Dollars.

          The Trustee shall have the right to decline to authenticate and
deliver any Debt Securities under this Section 2.05 if the Trustee, being
advised by counsel, determines that such action may not lawfully be taken or if
the Trustee in good faith by its board of directors or

                                       13
<PAGE>

trustees, executive committee or a trust committee of directors, trustees or
vice presidents shall determine that such action would expose the Trustee to
personal liability to existing Holders.

          The Trustee may appoint an authenticating agent reasonably acceptable
to the Issuers to authenticate Debt Securities of any series. Unless limited by
the terms of such appointment, an authenticating agent may authenticate Debt
Securities whenever the Trustee may do so. Each reference in the Indenture to
authentication by the Trustee includes authentication by such agent. An
authenticating agent has the same rights as any Registrar, paying agent or agent
for service of notices and demands.

          SECTION 2.06.  Denomination of Debt Securities. Unless otherwise
                         -------------------------------
provided in the form of Debt Security for any series, the Debt Securities of
each series shall be issuable only as Registered Securities in such
denominations as shall be specified or contemplated by Section 2.03. In the
absence of any such specification with respect to the Debt Securities of any
series, the Debt Securities of such series shall be issuable in denominations of
$1,000 and any integral multiple thereof.

          SECTION 2.07.  General Provisions for Registration of Transfer and
                         ---------------------------------------------------
Exchange. (a) The Issuers shall keep or cause to be kept a register for each
--------
series of Registered Securities issued hereunder (hereinafter collectively
referred to as the "Debt Security Register"), in which, subject to such
reasonable regulations as they may prescribe, the Issuers shall provide for the
registration of Registered Securities and the transfer of Registered Securities
as in this Article II provided. At all reasonable times the Debt Security
Register shall be open for inspection by the Trustee. Subject to Section 2.15,
upon due presentment for registration of transfer of any Registered Security at
any office or agency to be maintained by the Issuers in accordance with the
provisions of Section 4.02, the Issuers shall execute and the Trustee shall
authenticate and deliver in the name of the transferee or transferees a new
Registered Security or Registered Securities of authorized denominations for a
like aggregate principal amount.

          Unless and until otherwise determined by a Board Resolution of each of
the Issuers, the register of the Issuers for the purpose of registration,
exchange or registration of transfer of the Registered Securities shall be kept
at the Corporate Trust Office of the Trustee and, for this purpose, the Trustee
shall be designated "Registrar". No prior notice to the Holders of Debt
Securities is required to effect the designation of a substitute Registrar by
the Issuers.

          Registered Securities of any series (other than a Global Security) may
be exchanged for a like aggregate principal amount of Registered Securities of
the same series of other authorized denominations. Subject to Section 2.15,
Registered Securities to be exchanged shall be surrendered at the office or
agency to be maintained by the Issuers as provided in Section 4.02, and the
Issuers shall execute and the Trustee shall authenticate and deliver in exchange
therefor the Registered Security or Registered Securities that the Holder making
the exchange shall be entitled to receive.

          (b)  All Registered Securities presented or surrendered for
registration of transfer, exchange or payment shall (if so required by the
Issuers, the Trustee or the Registrar) be duly endorsed or be accompanied by a
written instrument or instruments of transfer, in form

                                       14
<PAGE>

satisfactory to the Issuers, the Trustee and the Registrar, duly executed by the
Registered Holder or his attorney duly authorized in writing.

          All Debt Securities issued in exchange for or upon transfer of Debt
Securities shall be the legal, valid and binding obligations of the Issuers,
evidencing the same debt, and entitled to the same benefits under the Indenture
as the Debt Securities surrendered for such exchange or transfer.

          No service charge shall be made for any exchange or registration of
transfer of Debt Securities (except as provided by Section 2.09), but the
Issuers may require payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto, other than those
expressly provided in the Indenture to be made at the Issuers' own expense or
without expense or without charge to the Holders.

          The Issuers shall not be required (a) to issue, register the transfer
of or exchange any Debt Securities of a series either (i) during a period
beginning 15 Business Days next preceding any selection for redemption or
repurchase of Debt Securities of such series and ending on the close of business
on the day of giving the relevant notice of redemption or repurchase or (ii)
between a record date and the next succeeding interest payment date, or (b) to
register the transfer of or exchange any Debt Security called for redemption or
repurchase (except, in the case of Debt Securities to be redeemed or repurchased
in part, the portion not to be redeemed or repurchased).

          Specific procedures for registration of transfer and exchange of any
series of Debt Securities may be set forth in the applicable supplemental
Indenture for such Debt Securities.

          SECTION 2.08.  Temporary Debt Securities. Pending the preparation of
                         -------------------------
definitive Debt Securities of any series, the Issuers may execute and the
Trustee shall authenticate and deliver temporary Debt Securities (printed,
lithographed, photocopied, typewritten or otherwise produced) of any authorized
denomination, and substantially in the form of the definitive Debt Securities in
lieu of which they are issued, and with such omissions, insertions and
variations as may be appropriate for temporary Debt Securities, all as may be
determined by the Issuers with the concurrence of the Trustee. Temporary Debt
Securities may contain such reference to any provisions of the Indenture as may
be appropriate. Every temporary Debt Security shall be executed by the Issuers
and be authenticated by the Trustee upon the same conditions and in
substantially the same manner, and with like effect, as the definitive Debt
Securities.

          If temporary Debt Securities of any series are issued, the Issuers
will cause definitive Debt Securities of such series to be prepared without
unreasonable delay. After the preparation of definitive Debt Securities of such
series, the temporary Debt Securities of such series shall be exchangeable for
definitive Debt Securities of such series upon surrender of the temporary Debt
Securities of such series at the office or agency of the Issuers at a Place of
Payment for such series, without charge to the Holder thereof, except as
provided in Section 2.07 in connection with a transfer, and upon surrender for
cancellation of any one or more temporary Debt Securities of any series, the
Issuers shall execute and the Trustee shall authenticate and deliver in exchange
therefor a like principal amount of definitive Debt Securities of the same

                                       15
<PAGE>

series of authorized denominations and of like tenor. Until so exchanged,
temporary Debt Securities of any series shall in all respects be entitled to the
same benefits under the Indenture as definitive Debt Securities of such series,
except as otherwise specified as contemplated by Section 2.03(17) with respect
to the payment of interest on Global Securities in temporary form.

          Upon any exchange of a portion of a temporary Global Security for a
definitive Global Security or for the individual Debt Securities represented
thereby pursuant to Section 2.07 or this Section 2.08, the temporary Global
Security shall be endorsed by the Trustee to reflect the reduction of the
principal amount evidenced thereby, whereupon the principal amount of such
temporary Global Security shall be reduced for all purposes by the amount so
exchanged and endorsed.

          SECTION 2.09.  Mutilated, Destroyed, Lost or Stolen Debt Securities.
                         ----------------------------------------------------
If (i) any mutilated Debt Security is surrendered to the Trustee at the
Corporate Trust Office of the Trustee (in the case of Registered Securities) or
(ii) the Issuers and the Trustee receive evidence to their satisfaction of the
destruction, loss or theft of any Debt Security, and there is delivered to the
Issuers and the Trustee such security or indemnity as may be required by them to
save each of them and any paying agent harmless, and neither the Issuers nor the
Trustee receives written notice that such Debt Security has been acquired by a
bona fide purchaser, then the Issuers shall execute and, upon an Issuer Order,
the Trustee shall authenticate and deliver, in exchange for or in lieu of any
such mutilated, destroyed, lost or stolen Debt Security, a new Debt Security of
the same series of like tenor, form, terms and principal amount, bearing a
number not contemporaneously Outstanding. Upon the issuance of any substituted
Debt Security, the Issuers may require the payment of a sum sufficient to cover
any tax or other governmental charge that may be imposed in relation thereto and
any other expenses connected therewith. In case any Debt Security which has
matured or is about to mature or which has been called for redemption shall
become mutilated or be destroyed, lost or stolen, the Issuers may, instead of
issuing a substituted Debt Security, pay or authorize the payment of the same
(without surrender thereof except in the case of a mutilated Debt Security) if
the applicant for such payment shall furnish the Issuers and the Trustee with
such security or indemnity as either may require to save it harmless from all
risk, however remote, and, in case of destruction, loss or theft, evidence to
the satisfaction of the Issuers and the Trustee of the destruction, loss or
theft of such Debt Security and of the ownership thereof.

          Every substituted Debt Security of any series issued pursuant to the
provisions of this Section 2.09 by virtue of the fact that any Debt Security is
destroyed, lost or stolen shall constitute an original additional contractual
obligation of the Issuers, whether or not the destroyed, lost or stolen Debt
Security shall be found at any time, and shall be entitled to all the benefits
of the Indenture equally and proportionately with any and all other Debt
Securities of that series duly issued hereunder. All Debt Securities shall be
held and owned upon the express condition that the foregoing provisions are
exclusive with respect to the replacement or payment of mutilated, destroyed,
lost or stolen Debt Securities, and shall preclude any and all other rights or
remedies, notwithstanding any law or statute existing or hereafter enacted to
the contrary with respect to the replacement or payment of negotiable
instruments or other securities without their surrender, in each case to the
fullest extent permitted by law.

                                       16
<PAGE>

          SECTION 2.10.  Cancellation of Surrendered Debt Securities. All Debt
                         -------------------------------------------
Securities surrendered for payment, redemption, registration of transfer or
exchange shall, if surrendered to the Issuers or any paying agent or a
Registrar, be delivered to the Trustee for cancellation by it, or if surrendered
to the Trustee, shall be canceled by it, and no Debt Securities shall be issued
in lieu thereof except as expressly permitted by any of the provisions of the
Indenture. All canceled Debt Securities held by the Trustee shall be disposed of
by the Trustee in its customary manner. On request of the Issuers, the Trustee
shall deliver to the Issuers canceled Debt Securities held by the Trustee. If
the Issuers shall acquire any of the Debt Securities, however, such acquisition
shall not operate as a redemption or satisfaction of the indebtedness
represented thereby unless and until the same are delivered or surrendered to
the Trustee for cancellation. The Issuers may not issue new Debt Securities to
replace Debt Securities it has redeemed, paid or delivered to the Trustee for
cancellation.

          SECTION 2.11.  Provisions of the Indenture and Debt Securities for the
                         -------------------------------------------------------
Sole Benefit of the Parties and the Holders. Nothing in the Indenture or in the
-------------------------------------------
Debt Securities, expressed or implied, shall give or be construed to give to any
Person, other than the parties hereto, the Holders or any Registrar or paying
agent, any legal or equitable right, remedy or claim under or in respect of the
Indenture, or under any covenant, condition or provision herein contained, all
its covenants, conditions and provisions being for the sole benefit of the
parties hereto, the Holders and any Registrar and paying agents.

          SECTION 2.12.  Payment of Interest; Rights Preserved. (a) Interest on
                         -------------------------------------
any Registered Security that is payable and is punctually paid or duly provided
for on any interest payment date shall be paid to the Person in whose name such
Registered Security is registered at the close of business on the regular record
date for such interest notwithstanding the cancellation of such Registered
Security upon any transfer or exchange subsequent to the regular record date.
Payment of interest on Registered Securities shall be made at the Corporate
Trust Office of the Trustee (except as otherwise specified pursuant to Section
2.03), or at the option of the Issuers, by check mailed to the address of the
Person entitled thereto as such address shall appear in the Debt Security
Register or, if provided pursuant to Section 2.03 and in accordance with
arrangements satisfactory to the Trustee, at the option of the Registered Holder
by wire transfer to an account designated by the Registered Holder.

          (b)  Subject to the foregoing provisions of this Section 2.12 and
Section 2.17, each Debt Security of a particular series delivered under the
Indenture upon registration of transfer of or in exchange for or in lieu of any
other Debt Security of the same series shall carry the rights to interest
accrued and unpaid, and to accrue, which were carried by such other Debt
Security.

          SECTION 2.13.  Securities  Denominated  in Foreign  Currencies.  (a)
                         -----------------------------------------------
Except as otherwise specified pursuant to Section 2.03 for Registered Securities
of any series, payment of the principal of, and premium, if any, and interest
on, Registered Securities of such series will be made in Dollars.

          (b)  For the purposes of calculating the principal amount of Debt
Securities of any series denominated in a Foreign Currency or in units of two or
more Foreign Currencies for any purpose under the Indenture, the principal
amount of such Debt Securities at any time

                                       17
<PAGE>

Outstanding shall be deemed to be the Dollar Equivalent of such principal amount
as of the date of any such calculation.

          In the event any Foreign Currency or currencies or units of two or
more Currencies in which any payment with respect to any series of Debt
Securities may be made ceases to be a freely convertible Currency on United
States Currency markets, for any date thereafter on which payment of principal
of, or premium, if any, or interest on, the Debt Securities of a series is due,
the Issuers shall select the Currency of payment for use on such date, all as
provided in the Debt Securities of such series. In such event, the Issuers
shall, as provided in the Debt Securities of such series, notify the Trustee of
the Currency which they have selected to constitute the funds necessary to meet
the Issuers' obligations or such payment date and of the amount of such Currency
to be paid. Such amount shall be determined as provided in the Debt Securities
of such series. The payment to the Trustee with respect to such payment date
shall be made by the Issuers solely in the Currency so selected.

          SECTION 2.14.  Wire Transfers. Notwithstanding any other provision to
                         --------------
the contrary in the Indenture, the Issuers may make any payment of monies
required to be deposited with the Trustee on account of principal of, or
premium, if any, or interest on, the Debt Securities (whether pursuant to
optional or mandatory redemption payments, interest payments or otherwise) by
wire transfer of immediately available funds to an account designated by the
Trustee on or before the date such moneys are to be paid to the Holders of the
Debt Securities in accordance with the terms hereof.

          SECTION 2.15.  Securities Issuable in the Form of a Global Security.
                         ----------------------------------------------------
(a) If the Issuers shall establish pursuant to Sections 2.01 and 2.03 that the
Debt Securities of a particular series are to be issued in whole or in part in
the form of one or more Global Securities, then the Issuers shall execute and
the Trustee or its agent shall, in accordance with Section 2.05, authenticate
and deliver, such Global Security or Securities, which (i) shall represent, and
shall be denominated in an amount equal to the aggregate principal amount of,
the Outstanding Debt Securities of such series to be represented by such Global
Security or Securities, or such portion thereof as the Issuers shall specify in
an Officers' Certificate, (ii) shall be registered in the name of the Depositary
for such Global Security or securities or its nominee, (iii) shall be delivered
by the Trustee or its agent to the Depositary or pursuant to the Depositary's
instruction and (iv) shall bear a legend substantially to the following effect:
"Unless and until it is exchanged in whole or in part for the individual Debt
Securities represented hereby, this Global Security may not be transferred
except as a whole by the Depositary to a nominee of the Depositary or by a
nominee of the Depositary to the Depositary or another nominee of the Depositary
or by the Depositary or any such nominee to a successor Depositary or a nominee
of such successor Depositary", or such other legend as may then be required by
the Depositary for such Global Security or Securities.

          (b)  Notwithstanding any other provision of this Section 2.15 or of
Section 2.07 to the contrary, and subject to the provisions of paragraph (c)
below, unless the terms of a Global Security expressly permit such Global
Security to be exchanged in whole or in part for definitive Debt Securities in
registered form, a Global Security may be transferred, in whole but not in part
and in the manner provided in Section 2.07, only by the Depositary to a nominee
of the Depositary for such Global Security, or by a nominee of the Depositary to
the Depositary or another nominee of the Depositary, or by the Depositary or a
nominee of the Depositary to a

                                       18
<PAGE>

successor Depositary for such Global Security selected or approved by the
Issuers, or to a nominee of such successor Depositary.

          (c)   (i) If at any time the Depositary for a Global Security or
Securities notifies the Issuers that it is unwilling or unable to continue as
Depositary for such Global Security or Securities or if at any time the
Depositary for the Debt Securities for such series shall no longer be eligible
or in good standing under the Exchange Act or other applicable statute, rule or
regulation, the Issuers shall appoint a successor Depositary with respect to
such Global Security or Securities. If a successor Depositary for such Global
Security or Securities is not appointed by the Issuers within 90 days after the
Issuers receive such notice or become aware of such ineligibility, the Issuers
shall execute, and the Trustee or its agent, upon receipt of an Issuer Order for
the authentication and delivery of such individual Debt Securities of such
series in exchange for such Global Security, will authenticate and deliver,
individual Debt Securities of such series of like tenor and terms in definitive
form in an aggregate principal amount equal to the principal amount of the
Global Security in exchange for such Global Security or Securities.

          (ii)  The Issuers may at any time and in their sole discretion
determine that the Debt Securities of any series or portion thereof issued or
issuable in the form of one or more Global Securities shall no longer be
represented by such Global Security or Securities. In such event the Issuers
will execute, and the Trustee, upon receipt of an Issuer Order for the
authentication and delivery of individual Debt Securities of such series in
exchange in whole or in part for such Global Security, will authenticate and
deliver individual Debt Securities of such series of like tenor and terms in
definitive form in an aggregate principal amount equal to the principal amount
of such series or portion thereof in exchange for such Global Security or
Securities.

          (iii) If specified by the Issuers pursuant to Sections 2.01 and 2.03
with respect to Debt Securities issued or issuable in the form of a Global
Security, the Depositary for such Global Security may surrender such Global
Security in exchange in whole or in part for individual Debt Securities of such
series of like tenor and terms in definitive form on such terms as are
acceptable to the Issuers, the Trustee and such Depositary. Thereupon the
Issuers shall execute, and the Trustee or its agent upon receipt of an Issuer
Order for the authentication and delivery of definitive Debt Securities of such
series shall authenticate and deliver, without service charge, (1) to each
Person specified by such Depositary a new Debt Security or Securities of the
same series of like tenor and terms and of any authorized denomination as
requested by such Person in aggregate principal amount equal to and in exchange
for such Person's beneficial interest in the Global Security, and (2) to such
Depositary a new Global Security of like tenor and terms and in an authorized
denomination equal to the difference, if any, between the principal amount of
the surrendered Global Security and the aggregate principal amount of Debt
Securities delivered to Holders thereof, unless such Global Security is endorsed
by the Trustee or other custodian to reflect a reduction of such aggregate
principal amount, in which case no new Global Security need be authenticated and
delivered.

          (iv)  In any exchange provided for in any of the preceding three
paragraphs, the Issuers will execute and the Trustee or its agent will
authenticate and deliver individual Debt Securities. Upon the exchange of the
entire principal amount of a Global Security for individual Debt Securities,
such Global Security shall be canceled by the Trustee or its agent. Except as

                                       19
<PAGE>

provided in the preceding paragraph, Registered Securities issued in exchange
for a Global Security pursuant to this Section 2.15 shall be registered in such
names and in such authorized denominations as the Depositary for such Global
Security, pursuant to instructions from its direct or indirect participants or
otherwise, shall instruct the Trustee or the Registrar. The Trustee or the
Registrar shall deliver such Registered Securities to the Persons in whose names
such Registered Securities are so registered.

          (v)  Payments in respect of the principal of and interest on any Debt
Securities registered in the name of the Depositary or its nominee will be
payable to the Depositary or such nominee in its capacity as the registered
owner of such Global Security. The Issuers and the Trustee may treat the Person
in whose name the Debt Securities, including the Global Security, are registered
as the owner thereof for the purpose of receiving such payments and for any and
all other purposes whatsoever. None of the Issuers, the Trustee, any Registrar,
the paying agent or any agent of the Issuers or the Trustee will have any
responsibility or liability for (a) any aspect of the records relating to or
payments made on account of the beneficial ownership interests of the Global
Security by the Depositary or its nominee or any of the Depositary's direct or
indirect participants, or for maintaining, supervising or reviewing any records
of the Depositary, its nominee or any of the Depositary's direct or indirect
participants relating to the beneficial ownership interests of the Global
Security, (b) the payments to the beneficial owners of the Global Security of
amounts paid to the Depositary or its nominee, or (c) any other matter relating
to the actions and practices of the Depositary, its nominee or any of the
Depositary's direct or indirect participants. None of the Issuers, the Trustee
or any such agent will be liable for any delay by the Depositary, its nominee,
or any of the Depositary's direct or indirect participants in identifying the
beneficial owners of the Debt Securities, and the Issuers and the Trustee may
conclusively rely on, and will be protected in relying on, instructions from the
Depositary or its nominee for all purposes (including with respect to the
registration and delivery, and the respective principal amounts, of the Debt
Securities to be issued).

          SECTION 2.16.  Medium Term Securities. Notwithstanding any contrary
                         ----------------------
provision herein, if all Debt Securities of a series are not to be originally
issued at one time, it shall not be necessary for the Issuers to deliver to the
Trustee an Officers' Certificate, a Board Resolution, a supplemental Indenture,
an Opinion of Counsel or a written order or any other document otherwise
required pursuant to Section 2.01, 2.03, 2.05 or 12.05 at or prior to the time
of authentication of each Debt Security of such series if such documents are
delivered to the Trustee or its agent at or prior to the authentication upon
original issuance of the first such Debt Security of such series to be issued;
provided, that any subsequent request by the Issuers to the Trustee to
--------
authenticate Debt Securities of such series upon original issuance shall
constitute a representation and warranty by the Issuers that, as of the date of
such request, the statements made in the Officers' Certificate delivered
pursuant to Section 2.05 or 12.05 shall be true and correct as if made on such
date and that the Opinion of Counsel delivered at or prior to such time of
authentication of an original issuance of Debt Securities shall specifically
state that it shall relate to all subsequent issuances of Debt Securities of
such series that are identical to the Debt Securities issued in the first
issuance of Debt Securities of such series.

          An Issuer Order delivered by the Issuers to the Trustee in the
circumstances set forth in the preceding paragraph may provide that Debt
Securities which are the subject thereof will be authenticated and delivered by
the Trustee or its agent on original issue from time to time

                                       20
<PAGE>

upon the written order of Persons designated in such written order and that such
Persons are authorized to determine, consistent with the Officers' Certificates,
supplemental Indenture or the applicable Board Resolutions relating to such
written order, such terms and conditions of such Debt Securities as are
specified in such Officers' Certificates, supplemental Indenture or such Board
Resolutions.

          SECTION 2.17.  Defaulted Interest. Any interest on any Debt Security
                         ------------------
of a particular series which is payable, but is not punctually paid or duly
provided for, on the dates and in the manner provided in the Debt Securities of
such series and in the Indenture (herein called "Defaulted Interest") shall
forthwith cease to be payable to the Registered Holder thereof on the relevant
record date by virtue of having been such Registered Holder, and such Defaulted
Interest may be paid by the Issuers, at their election in each case, as provided
in clause (i) or (ii) below:

          (i)  The Issuers may elect to make payment of any Defaulted Interest
     to the Persons in whose names the Registered Securities of such series are
     registered at the close of business on a special record date for the
     payment of such Defaulted Interest, which shall be fixed in the following
     manner: The Issuers shall notify the Trustee in writing of the amount of
     Defaulted Interest proposed to be paid on each such Registered Security of
     such series and the date of the proposed payment, and at the same time the
     Issuers shall deposit with the Trustee an amount of money equal to the
     aggregate amount proposed to be paid in respect of such Defaulted Interest
     or shall make arrangements satisfactory to the Trustee for such deposit
     prior to the date of the proposed payment, such money when deposited to be
     held in trust for the benefit of the Persons entitled to such Defaulted
     Interest as in this clause provided. Thereupon the Trustee shall fix a
     special record date for the payment of such Defaulted Interest which shall
     be not more than 15 days and not less than 10 days prior to the date of the
     proposed payment and not less than 10 days after the receipt by the Trustee
     of the notice of the proposed payment. The Trustee shall promptly notify
     the Issuers of such special record date and, in the name and at the expense
     of the Issuers, shall cause notice of the proposed payment of such
     Defaulted Interest and the special record date therefor to be mailed, first
     class postage prepaid, to each Holder thereof at its address as it appears
     in the Debt Security Register, not less than 10 days prior to such special
     record date. Notice of the proposed payment of such Defaulted Interest and
     the special record date therefor having been so mailed, such Defaulted
     Interest shall be paid to the Persons in whose names the Registered
     Securities of such series are registered at the close of business on such
     special record date.

          (ii) The Issuers may make payment of any Defaulted Interest on the
     Registered Securities of such series in any other lawful manner not
     inconsistent with the requirements of any securities exchange on which the
     Registered Securities of such series may be listed, and upon such notice as
     may be required by such exchange, if, after notice given by the Issuers to
     the Trustee of the proposed payment pursuant to this clause, such manner of
     payment shall be deemed practicable by the Trustee.

          SECTION 2.18.  Judgments. The Issuers may provide pursuant to Section
                         ---------
2.03 for Debt Securities of any series that (a) the obligation, if any, of the
Issuers to pay the principal

                                       21
<PAGE>

of, and premium, if any, and interest on, the Debt Securities of any series in a
Foreign Currency or Dollars (the "Designated Currency") as may be specified
pursuant to Section 2.03 is of the essence and agrees that, to the fullest
extent possible under applicable law, judgments in respect of Debt Securities of
such series shall be given in the Designated Currency; (b) the obligation of the
Issuers to make payments in the Designated Currency of the principal of, and
premium, if any, and interest on, such Debt Securities shall, notwithstanding
any payment in any other Currency (whether pursuant to a judgment or otherwise),
be discharged only to the extent of the amount in the Designated Currency that
the Holder receiving such payment may, in accordance with normal banking
procedures, purchase with the sum paid in such other Currency (after any premium
and cost exchange) on the business day in the country of issue of the Designated
Currency or in the international banking community (in the case of a composite
currency) immediately following the day on which such Holder receives such
payment; (c) if the amount in the Designated Currency that may be so purchased
for any reason falls short of the amount originally due, the Issuers shall pay
such additional amounts as may be necessary to compensate for such shortfall;
and (d) any obligation of the Issuers not discharged by such payment shall be
due as a separate and independent obligation and, until discharged as provided
herein, shall continue in full force and effect.

          SECTION 2.19.  CUSIP Numbers. The Issuers in issuing the Debt
                         -------------
Securities may use "CUSIP" numbers (if then generally in use), and, if so, the
Trustee shall use "CUSIP" numbers in notices of redemption as a convenience to
Holders; provided that any such notice may state that no representation is made
as to the correctness of such numbers either as printed on the Debt Securities
or as contained in any notice of a redemption and that reliance may be placed
only on the other identification numbers printed on the Debt Securities, and any
such redemption shall not be affected by any defect in or omission of such
numbers. The Issuers will promptly notify the Trustee of any change in the
"CUSIP" numbers.

                                  ARTICLE III

                         Redemption of Debt Securities
                         -----------------------------

          SECTION 3.01.  Applicability of Article. The provisions of this
                         ------------------------
Article shall be applicable to the Debt Securities of any series which are
redeemable before their Stated Maturity except as otherwise specified as
contemplated by Section 2.03 for Debt Securities of such series.

          SECTION 3.02.  Notice of Redemption; Selection of Debt Securities. In
                         --------------------------------------------------
case the Issuers shall desire to exercise the right to redeem all or, as the
case may be, any part of the Debt Securities of any series in accordance with
their terms, a Board Resolution of each Issuer or a supplemental Indenture, the
Issuers shall fix a date for redemption and shall give notice of such redemption
at least 30 and not more than 60 days prior to the date fixed for redemption to
the Holders of Debt Securities of such series so to be redeemed as a whole or in
part, in the manner provided in Section 12.03. The notice may not be
conditional. The notice if given in the manner herein provided shall be
conclusively presumed to have been duly given, whether or not the Holder
receives such notice. In any case, failure to give such notice or any defect in
the notice to the Holder of any Debt Security of a series designated for
redemption as a whole or in part shall not affect the validity of the
proceedings for the redemption of any other Debt Security of such series.

                                       22
<PAGE>

          Each such notice of redemption shall specify the amount of Debt
Securities of any series to be redeemed, the date fixed for redemption, the
calculation of the redemption price at which Debt Securities of such series are
to be redeemed (but not the redemption price itself if it is not then
determinable), the Place or Places of Payment that payment will be made upon
presentation and surrender of such Debt Securities, that any interest accrued to
the date fixed for redemption will be paid as specified in said notice, that the
redemption is for a sinking fund payment (if applicable), that on and after said
date any interest thereon or on the portions thereof to be redeemed will cease
to accrue, that in the case of Original Issue Discount Securities original issue
discount accrued after the date fixed for redemption will cease to accrue, the
terms of the Debt Securities of that series pursuant to which the Debt
Securities of that series are being redeemed and that no representation is made
as to the correctness or accuracy of the CUSIP number, if any, listed in such
notice or printed on the Debt Securities of that series. If less than all the
Debt Securities of a series are to be redeemed the notice of redemption shall
specify the CUSIP numbers of the Debt Securities of that series to be redeemed.
In case any Debt Security of a series is to be redeemed in part only, the notice
of redemption shall state the portion of the principal amount thereof to be
redeemed and shall state that on and after the date fixed for redemption, upon
surrender of such Debt Security, a new Debt Security or Debt Securities of that
series will be issued in principal amount equal to the unredeemed portion
thereof.

          At least 60 days before the redemption date, unless the Trustee
consents to a shorter period, the Issuers shall give written notice to the
Trustee of the redemption date, the principal amount of Debt Securities to be
redeemed and the series and terms of the Debt Securities pursuant to which such
redemption will occur. Such notice shall be accompanied by an Officers'
Certificate and an Opinion of Counsel to the effect that such redemption will
comply with the conditions herein. If fewer than all the Debt Securities of a
series are to be redeemed, the record date relating to such redemption shall be
selected by the Issuers and given to the Trustee, which record date shall be not
less than 15 days after the date of notice to the Trustee.

          No later than 11:00 A.M., New York City time, on the redemption date
for any Debt Securities, the Issuers shall deposit with the Trustee or with a
paying agent (or, if the Partnership or PAA Finance is acting as its own paying
agent, segregate and hold in trust) an amount of money in the Currency in which
such Debt Securities are denominated (except as provided pursuant to Section
2.03) sufficient to pay the redemption price of such Debt Securities or any
portions thereof that are to be redeemed on that date.

          If less than all the Debt Securities of like tenor and terms of a
series are to be redeemed (other than pursuant to mandatory sinking fund
redemptions), the Trustee shall select the Debt Securities of that series or
portions thereof (in multiples of $1,000) to be redeemed (i) if such Debt
Securities are listed on an exchange, in compliance with the requirements of the
principal national securities exchange on which such Debt Securities are listed,
or (ii) if such Debt Securities are not listed on an exchange or such exchange
has no selection requirements, on a pro rata basis, by lot or by such other
method as in its sole discretion the Trustee shall deem appropriate and fair. In
any case where more than one Debt Security of such series is registered in the
same name, the Trustee in its discretion may treat the aggregate principal
amount so registered as if it were represented by one Debt Security of such
series. The Trustee shall promptly notify the Issuers in writing of the Debt
Securities selected for redemption and, in the

                                       23
<PAGE>

case of any Debt Securities selected for partial redemption, the principal
amount thereof to be redeemed. If any Debt Security called for redemption shall
not be so paid upon surrender thereof on such redemption date, the principal,
premium, if any, and interest shall bear interest until paid from the redemption
date at the rate borne by the Debt Securities of that series. If less than all
the Debt Securities of unlike tenor and terms of a series are to be redeemed,
the particular Debt Securities to be redeemed shall be selected by the Issuers.
Provisions of the Indenture that apply to Debt Securities called for redemption
also apply to portions of Debt Securities called for redemption.

          SECTION 3.03.  Payment of Debt Securities Called for Redemption. If
                         ------------------------------------------------
notice of redemption has been given as provided in Section 3.02, the Debt
Securities or portions of Debt Securities of the series with respect to which
such notice has been given shall become due and payable on the date and at the
Place or Places of Payment stated in such notice at the applicable redemption
price, together with any interest accrued to the date fixed for redemption, and
on and after said date (unless the Issuers shall default in the payment of such
Debt Securities at the applicable redemption price, together with any interest
accrued to said date) any interest on the Debt Securities or portions of Debt
Securities of any series so called for redemption shall cease to accrue and any
original issue discount in the case of Original Issue Discount Securities shall
cease to accrue. On presentation and surrender of such Debt Securities at the
Place or Places of Payment in said notice specified, the said Debt Securities or
the specified portions thereof shall be paid and redeemed by the Issuers at the
applicable redemption price, together with any interest accrued thereon to the
date fixed for redemption.

          Any Debt Security that is to be redeemed only in part shall be
surrendered at the Corporate Trust Office of the Trustee or such other office or
agency of the Issuers as is specified pursuant to Section 2.03, if the Issuers,
the Registrar or the Trustee so requires, due endorsement by, or a written
instrument of transfer in form satisfactory to the Issuers, the Registrar and
the Trustee duly executed by, the Holder thereof or his attorney duly authorized
in writing, and the Issuers shall execute, and the Trustee shall authenticate
and deliver to the Holder of such Debt Security without service charge, a new
Debt Security or Debt Securities of the same series, of like tenor and form, of
any authorized denomination as requested by such Holder in aggregate principal
amount equal to and in exchange for the unredeemed portion of the principal of
the Debt Security so surrendered; except that if a Global Security is so
surrendered, the Issuers shall execute, and the Trustee shall authenticate and
deliver to the Depositary for such Global Security, without service charge, a
new Global Security in a denomination equal to and in exchange for the
unredeemed portion of the principal of the Global Security so surrendered. In
the case of a Debt Security providing appropriate space for such notation, at
the option of the Holder thereof, the Trustee, in lieu of delivering a new Debt
Security or Debt Securities as aforesaid, may make a notation on such Debt
Security of the payment of the redeemed portion thereof.

          SECTION 3.04.  Mandatory and Optional Sinking Funds. The minimum
                         ------------------------------------
amount of any sinking fund payment provided for by the terms of Debt Securities
of any series, a Board Resolution or a supplemental Indenture is herein referred
to as a "mandatory sinking fund payment", and any payment in excess of such
minimum amount provided for by the terms of Debt Securities of any series, a
Board Resolution or a supplemental Indenture is herein referred to as an
"optional sinking fund payment."

                                       24
<PAGE>

          In lieu of making all or any part of any mandatory sinking fund
payment with respect to any Debt Securities of a series in cash, the Issuers may
at their option (a) deliver to the Trustee Debt Securities of that series
theretofore purchased or otherwise acquired by the Issuers or (b) receive credit
for the principal amount of Debt Securities of that series which have been
redeemed either at the election of the Issuers pursuant to the terms of such
Debt Securities or through the application of permitted optional sinking fund
payments pursuant to the terms of such Debt Securities, resolution or
supplemental Indenture; provided, that such Debt Securities have not been
previously so credited. Such Debt Securities shall be received and credited for
such purpose by the Trustee at the redemption price specified in such Debt
Securities, the applicable Board Resolution or supplemental Indenture for
redemption through operation of the sinking fund and the amount of such
mandatory sinking fund payment shall be reduced accordingly.

          SECTION 3.05.  Redemption of Debt Securities for Sinking Fund. Not
                         ----------------------------------------------
less than 60 days prior to each sinking fund payment date for any series of Debt
Securities, the Issuers will deliver to the Trustee an Officers' Certificate
specifying the amount of the next ensuing sinking fund payment for that series
pursuant to the terms of that series, any Board Resolution or supplemental
Indenture, the portion thereof, if any, which is to be satisfied by payment of
cash in the Currency in which the Debt Securities of such series are denominated
(except as provided pursuant to Section 2.03) and the portion thereof, if any,
which is to be satisfied by delivering and crediting Debt Securities of that
series pursuant to this Section 3.05 (which Debt Securities, if not previously
redeemed, will accompany such certificate) and whether the Issuers intend to
exercise their right to make any permitted optional sinking fund payment with
respect to such series. Such certificate shall also state that no Event of
Default has occurred and is continuing with respect to such series. Such
certificate shall be irrevocable and upon its delivery the Issuers shall be
obligated to make the cash payment or payments therein referred to, if any, on
or before the next succeeding sinking fund payment date. Failure of the Issuers
to deliver such certificate (or to deliver the Debt Securities specified in this
paragraph) shall not constitute a Default, but such failure shall require that
the sinking fund payment due on the next succeeding sinking fund payment date
for that series shall be paid entirely in cash and shall be sufficient to redeem
the principal amount of such Debt Securities subject to a mandatory sinking fund
payment without the option to deliver or credit Debt Securities as provided in
this Section 3.05 and without the right to make any optional sinking fund
payment, if any, with respect to such series.

          Any sinking fund payment or payments (mandatory or optional) made in
cash plus any unused balance of any preceding sinking fund payments made in cash
which shall equal or exceed $100,000 (or a lesser sum if the Issuers shall so
request) with respect to the Debt Securities of any particular series shall be
applied by the Trustee on the sinking fund payment date on which such payment is
made (or, if such payment is made before a sinking fund payment date, on the
sinking fund payment date following the date of such payment) to the redemption
of such Debt Securities at the redemption price specified in such Debt
Securities, the applicable Board Resolution or supplemental Indenture for
operation of the sinking fund together with any accrued interest to the date
fixed for redemption. Any sinking fund moneys not so applied or allocated by the
Trustee to the redemption of Debt Securities shall be added to the next cash
sinking fund payment received by the Trustee for such series and, together with
such payment, shall be applied in accordance with the provisions of this Section
3.05. Any and all sinking fund moneys with respect to the Debt Securities of any
particular series held by the Trustee on the last

                                       25
<PAGE>

sinking fund payment date with respect to Debt Securities of such series and not
held for the payment or redemption of particular Debt Securities shall be
applied by the Trustee, together with other moneys, if necessary, to be
deposited sufficient for the purpose, to the payment of the principal of the
Debt Securities of that series at its Stated Maturity.

          The Trustee shall select the Debt Securities to be redeemed upon such
sinking fund payment date in the manner specified in the last paragraph of
Section 3.02 and the Issuers shall cause notice of the redemption thereof to be
given in the manner provided in Section 3.02 except that the notice of
redemption shall also state that the Debt Securities are being redeemed by
operation of the sinking fund. Such notice having been duly given, the
redemption of such Debt Securities shall be made upon the terms and in the
manner stated in Section 3.03.

          At least one business day before each sinking fund payment date, the
Issuers shall pay to the Trustee (or, if the Partnership or PAA Finance is
acting as its own paying agent, the Partnership or PAA Finance shall segregate
and hold in trust) in cash a sum in the Currency in which the Debt Securities of
such series are denominated (except as provided pursuant to Section 2.03) equal
to any interest accrued to the date fixed for redemption of Debt Securities or
portions thereof to be redeemed on such sinking fund payment date pursuant to
this Section 3.05.

          The Trustee shall not redeem any Debt Securities of a series with
sinking fund moneys or mail any notice of redemption of such Debt Securities by
operation of the sinking fund for such series during the continuance of a
Default in payment of interest on such Debt Securities or of any Event of
Default (other than an Event of Default occurring as a consequence of this
paragraph) with respect to such Debt Securities, except that if the notice of
redemption of any such Debt Securities shall theretofore have been mailed in
accordance with the provisions hereof, the Trustee shall redeem such Debt
Securities if cash sufficient for that purpose shall be deposited with the
Trustee for that purpose in accordance with the terms of this Article III.
Except as aforesaid, any moneys in the sinking fund for such series at the time
when any such Default or Event of Default shall occur and any moneys thereafter
paid into such sinking fund shall, during the continuance of such Default or
Event of Default, be held as security for the payment of such Debt Securities;
provided, however, that in case such Default or Event of Default shall have been
--------  -------
cured or waived as provided herein, such moneys shall thereafter be applied on
the next sinking fund payment date for such Debt Securities on which such moneys
may be applied pursuant to the provisions of this Section 3.05.

                                  ARTICLE IV

                      Particular Covenants of the Issuers
                      -----------------------------------

          SECTION 4.01.  Payment of Principal of, and Premium, If Any, and
Interest on, Debt Securities. The Issuers, for the benefit of each series of
Debt Securities, will duly and punctually pay or cause to be paid the principal
of, and premium, if any, and interest on, each of the Debt Securities at the
place, at the respective times and in the manner provided herein and in the Debt
Securities. Each installment of interest on the Debt Securities may at the
Issuers' option be paid by mailing checks for such interest payable to the
Person entitled thereto to the address of such Person as it appears on the Debt
Security Register maintained pursuant to Section 2.07(a).

                                       26
<PAGE>

          Principal, premium and interest in respect of Debt Securities of any
series shall be considered paid on the date due if no later than 11:00 A.M., New
York City time, on such date the Trustee or any paying agent holds in accordance
with the Indenture money sufficient to pay in the Currency in which the Debt
Securities of such series are denominated (except as provided pursuant to
Section 2.03) all principal, premium and interest then due.

          The Issuers shall pay interest on overdue principal at the rate
specified therefor in the Debt Securities and they shall pay interest on overdue
installments of interest at the same rate to the extent lawful.

          SECTION 4.02.  Maintenance of Offices or Agencies for Registration of
                         ------------------------------------------------------
Transfer, Exchange and Payment of Debt Securities. The Issuers will maintain in
-------------------------------------------------
each Place of Payment for any series of Debt Securities, an office or agency
where Debt Securities of such series may be presented or surrendered for
payment, where Debt Securities of such series may be surrendered for transfer or
exchange and where notices and demands to or upon the Issuers in respect of the
Debt Securities of such series and the Indenture may be served. The Issuers will
give prompt written notice to the Trustee of the location, and any change in the
location, of such office or agency. If at any time the Issuers shall fail to
maintain any such required office or agency or shall fail to furnish the Trustee
with the address thereof, such presentations, surrenders, notices and demands
may be made or served at the Corporate Trust Office of the Trustee, and the
Issuers hereby appoint the Trustee as its agent to receive all presentations,
surrenders, notices and demands.

          The Issuers may also from time to time designate different or
additional offices or agencies to be maintained for such purposes (in or outside
of such Place of Payment), and may from time to time rescind any such
designation; provided, however, that no such designation or rescission shall in
any manner relieve the Issuers of their obligations described in the preceding
paragraph. The Issuers will give prompt written notice to the Trustee of any
such additional designation or rescission of designation and any change in the
location of any such different or additional office or agency.

          SECTION 4.03.  Appointment to Fill a Vacancy in the Office of Trustee.
                         ------------------------------------------------------
The Issuers, whenever necessary to avoid or fill a vacancy in the office of
Trustee, will appoint, in the manner provided in Section 7.08, a Trustee, so
that there shall at all times be a Trustee hereunder with respect to each series
of Debt Securities.

          SECTION 4.04.  Duties of Paying Agents, etc. (a) The Issuers shall
                         -----------------------------
cause each paying agent, if any, other than the Trustee, to execute and deliver
to the Trustee an instrument in which such agent shall agree with the Trustee,
subject to the provisions of this Section 4.04,

          (i)   that it will hold all sums held by it as such agent for the
     payment of the principal of, and premium, if any, or interest on, the Debt
     Securities of any series (whether such sums have been paid to it by the
     Issuers or by any other obligor on the Debt Securities of such series) in
     trust for the benefit of the Holders of the Debt Securities of such series;

                                       27
<PAGE>

          (ii)  that it will give the Trustee notice of any failure by the
     Issuers (or by any other obligor on the Debt Securities of such series) to
     make any payment of the principal of and premium, if any, or interest on,
     the Debt Securities of such series when the same shall be due and payable;
     and

          (iii) that it will at any time during the continuance of an Event of
     Default, upon the written request of the Trustee, forthwith pay to the
     Trustee all sums so held by it as such agent.

          (b)   If either of the Issuers or any of their respective Subsidiaries
shall act as its own paying agent, it will, on or before 11:00 A.M., New York
City time, on each due date of the principal of, and premium, if any, or
interest on, the Debt Securities if any, of any series, set aside, segregate and
hold in trust for the benefit of the Holders of the Debt Securities of such
series a sum sufficient to pay such principal, premium, if any, or interest so
becoming due. The Issuers will promptly notify the Trustee of any failure by the
Issuers or its Subsidiaries to take such action or the failure by any other
obligor on such Debt Securities to make any payment of the principal of, and
premium, if any, or interest on, such Debt Securities when the same shall be due
and payable.

          (c)   Anything in this Section 4.04 to the contrary notwithstanding,
either of the Issuers may, at any time, for the purpose of obtaining a
satisfaction and discharge of the Indenture, or for any other reason, pay or
cause to be paid to the Trustee all sums held in trust by it or any paying
agent, as required by this Section 4.04, such sums to be held by the Trustee
upon the same terms as those upon which such sums were held by the Issuers or
such paying agent.

          (d)   Whenever the Issuers shall have one or more paying agents with
respect to any series of Debt Securities, they will, prior to 11:00 A.M., New
York City time, on each due date of the principal of, and premium, if any, or
interest on, any Debt Securities of such series, deposit with any such paying
agent a sum sufficient to pay the principal, premium or interest so becoming
due, such sum to be held in trust for the benefit of the Persons entitled
thereto, and (unless any such paying agent is the Trustee) the Issuers will
promptly notify the Trustee of their action or failure so to act.

          (e)   Anything in this Section 4.04 to the contrary notwithstanding,
the agreement to hold sums in trust as provided in this Section 4.04 is subject
to the provisions of Section 11.02.

          (f)   Unless and until otherwise determined by the Issuers in Board
Resolutions or pursuant to a supplemental Indenture, the Trustee will act as
paying agent under the Indenture. The Issuers may designate a substitute paying
agent without prior notice to the Holders of Debt Securities.

          SECTION 4.05.  Statement by Officers as to Default. The Issuers will
                         -----------------------------------
deliver to the Trustee, on or before a date not more than four months after the
end of each fiscal year of the Issuers (currently ending on December 31 of each
year) ending after the date hereof, an Officers' Certificate stating, as to each
officer signing such certificate, one of whom shall be the principal executive,
financial or accounting officer of each Issuer, that (i) in the course of his
performance

                                       28
<PAGE>

of his duties as an officer of the Managing General Partner or PAA Finance, as
applicable, he would normally have knowledge of any Default, (ii) whether or not
to the best of his knowledge any Default occurred during such year and (iii) if
to the best of his knowledge the Partnership or PAA Finance, as applicable, is
in Default, specifying all such Defaults and what action the Partnership or PAA
Finance, as applicable, is taking or proposes to take with respect thereto.

          SECTION 4.06.  Further Instruments and Acts. The Issuers will, upon
                         ----------------------------
request of the Trustee, execute and deliver such further instruments and do such
further acts as may reasonably be necessary or proper to carry out more
effectually the purposes of the Indenture.

          SECTION 4.07.  Corporate, Partnership or Limited Liability Company
                         ---------------------------------------------------
Existence. Subject to Article X, the Issuers shall do or cause to be done all
---------
things necessary to preserve and keep in full force and effect the corporate,
partnership or limited liability company existence and related rights and
franchises (charges and statutory) of the Partnership and each of its
Subsidiaries; provided, however, that the Partnership shall not be required to
              --------  -------
preserve any such right or franchise for the corporate, partnership or limited
liability company existence of any such Subsidiary if the management of the
Managing General Partner shall determine that the preservation thereof is no
longer desirable in the conduct of the business of the Partnership and its
Subsidiaries as a whole and that the loss thereof would not reasonably be
expected to have a material adverse effect on the ability of the Issuers or any
obligor on the Debt Securities of any series to perform their obligations
hereunder; and provided, further, however, that the foregoing shall not prohibit
               --------  -------  -------
a sale, transfer or conveyance of a Subsidiary of the Partnership or any of its
assets in compliance with the terms of the Indenture.

          SECTION 4.08.  Maintenance of Properties. The Partnership shall cause
                         -------------------------
all material properties owned by the Partnership or any of its Subsidiaries or
used or held for use in the conduct of its business or the business of any of
its Subsidiaries to be maintained and kept in good condition, repair and working
order (ordinary wear and tear excepted) and supplied with all necessary
equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the reasonable
judgment of the Partnership may be consistent with sound business practice and
necessary so that the business carried on in connection therewith may be
properly conducted at all times; provided, however, that nothing in this Section
                                 --------  -------
shall prevent the Partnership from discontinuing the maintenance of any of such
properties if such discontinuance is, in the reasonable judgment of the
management of the Managing General Partner, desirable in the conduct of its
business or the business of any of its Subsidiaries and not reasonably expected
to have a material adverse effect on the ability of the Issuers or any obligor
on the Debt Securities of any series to perform their obligations hereunder.

          SECTION 4.09.  Payment of Taxes and Other Claims. The Partnership
                         ---------------------------------
shall pay or discharge or cause to be paid or discharged, on or before the date
the same shall become due and payable, (a) all taxes, assessments and
governmental charges levied or imposed upon the Partnership or any of its
Subsidiaries or otherwise assessed or upon the income, profits or property of
the Partnership or any of its Subsidiaries if failure to pay or discharge the
same could reasonably be expected to have a material adverse effect on the
ability of the Issuers or any obligor on the Debt Securities of any series to
perform their obligations hereunder and (b) all lawful claims for labor,
materials and supplies, which, if unpaid, would by law become a Lien upon the
property of the Partnership or any of its Subsidiaries, except for any Lien
permitted to

                                       29
<PAGE>

be incurred under the terms of the Indenture, if failure to pay or
discharge the same could reasonably be expected to have a material adverse
effect on the ability of the Issuers or any obligor on the Debt Securities of
any series to perform their obligations hereunder; provided, however, that the
                                                   --------  -------
Partnership shall not be required to pay or discharge or cause to be paid or
discharged any such tax, assessment, charge or claim whose amount, applicability
or validity is being contested in good faith by appropriate proceedings properly
instituted and diligently conducted and in respect of which appropriate reserves
(in the good faith judgment of management of the Managing General Partner) are
being maintained in accordance with GAAP.

          SECTION 4.10.  Calculation of Original Issue Discount. The Issuers
                         --------------------------------------
shall file with the Trustee promptly at the end of each calendar year (i) a
written notice specifying the amount of original issue discount (including daily
rates and accrual periods) accrued on Outstanding Original Issue Discount Debt
Securities as of the end of such year and (ii) such other specific information
relating to such original issue discount as may then be relevant under the Code.

          SECTION 4.11.  Stay, Extension and Usury Laws. Each of the Issuers
                         ------------------------------
covenants (to the extent that it may lawfully do so) that it shall not at any
time insist upon, plead or in any manner whatsoever claim or take the benefit or
advantage of, any stay, extension or usury law wherever enacted, now or at any
time hereafter in force, that may affect the covenants or the performance of the
Indenture; and each of the Issuers hereby expressly waives all benefit or
advantage of any such law, and covenants that it shall not, by resort to any
such law, hinder, delay or impede the execution of any power herein granted to
the Trustee, but shall suffer and permit the execution of every such power as
though no such law has been enacted.

                                   ARTICLE V

                          Holders' Lists and Reports
                          --------------------------
                        by the Issuers and the Trustee
                        ------------------------------

          SECTION 5.01.  Issuers to Furnish Trustee Information as to Names and
                         ------------------------------------------------------
Addresses of Holders; Preservation of Information. The Issuers covenant and
-------------------------------------------------
agree that they will furnish or cause to be furnished to the Trustee with
respect to the Registered Securities of each series:

          (a)  not more than 15 days after each record date with respect to the
     payment of interest, if any, a list, in such form as the Trustee may
     reasonably require, of the names and addresses of the Registered Holders as
     of such record date, and

          (b)  at such other times as the Trustee may request in writing, within
     30 days after the receipt by the Issuers of any such request, a list as of
     a date not more than 15 days prior to the time such list is furnished;

provided, however, that so long as the Trustee shall be the Registrar, such
--------  -------
lists shall not be required to be furnished.

          The Trustee shall preserve, in as current a form as is reasonably
practicable, all information as to the names and addresses of the Holders (1)
contained in the most recent list

                                       30
<PAGE>

furnished to it as provided in this Section 5.01 or (2) received by it in the
capacity of paying agent or Registrar (if so acting) hereunder.

          The Trustee may destroy any list furnished to it as provided in this
Section 5.01 upon receipt of a new list so furnished.

          SECTION 5.02.  Communications to Holders; Meetings of Holders. (a)
                         ----------------------------------------------
Holders may communicate pursuant to Section 312(b) of the Trust Indenture Act
with other Holders with respect to their rights under the Indenture or the Debt
Securities. The Issuers, the Trustee, the Registrar and anyone else shall have
the protection of Section 312(c) of the Trust Indenture Act.

          (b)  A meeting of the Holders of Debt Securities of any or all series
may be called at any time and from time to time pursuant to this Section 5.02 to
make, give or take any request, demand, authorization, direction, notice,
consent, waiver or other action provided herein to be made, given or taken by
Holders of Debt Securities of such series.

          (c)  The Trustee may at any time call a meeting of Holders of Debt
Securities of any series for any purpose specified herein to be held at such
time and at such place in Houston, Texas, in The Borough of Manhattan, The City
of New York or in any other location, as the Trustee shall determine. Notice of
every meeting of Holders of any series, setting forth the time and the place of
such meeting and in general terms the action proposed to be taken at such
meeting, shall be given not less than 20 nor more than 180 days prior to the
date fixed for the meeting.

          (d)  In case at any time the Issuers, pursuant to Board Resolutions,
or the Holders of at least 10% in aggregate principal amount of the outstanding
Debt Securities of any series, shall have requested the Trustee for any such
series to call a meeting of the Holders of Debt Securities of such series for
any purpose specified herein, by written request setting forth in reasonable
detail the action proposed to be taken at the meeting, and the Trustee shall not
have made the first publication of the notice of such meeting within 30 days
after receipt of such request or shall not thereafter proceed to cause the
meeting to be held as provided herein, then the Issuers or the Holders of such
series in the amount specified above, as the case may be, may determine the time
and the place in Houston, Texas, in The Borough of Manhattan, The City of New
York, or in any other location, for such meeting and may call such meeting for
such purposes by giving notice thereof as provided in paragraph (c) of this
Section 5.02.

          SECTION 5.03.  Reports by Issuers. (a) Notwithstanding that the
                         ------------------
Partnership may not be required to remain subject to the reporting requirements
of Section 13 or 15(d) of the Exchange Act, the Partnership shall file with the
Commission and provide to the Trustee and the Holders of Debt Securities the
annual reports and the information, documents and other reports that are
specified in Sections 13 and 15(d) of the Exchange Act, and, with respect to the
annual consolidated financial statements only, a report thereon by the Issuers'
independent auditors; provided, however, that the Partnership shall not be so
                      --------  -------
obligated to file such information, documents and reports with the Commission if
the Commission does not permit such filings. The Issuers shall comply with the
other provisions of Section 314(a) of the Trust Indenture Act.

                                       31
<PAGE>

          (b)  The Issuers covenant and agree, and any obligor hereunder shall
covenant and agree, to file with the Trustee and the Commission, in accordance
with the rules and regulations prescribed from time to time by said Commission,
such additional information, documents, and reports with respect to compliance
by the Issuers or such obligor, as the case may be, with the conditions and
covenants provided for in the Indenture as may be required from time to time by
such rules and regulations.

          (c)  Delivery of such reports, information and documents to the
Trustee is for informational purposes only and the Trustee's receipt of such
shall not constitute notice of any information contained therein or determinable
from information contained therein, including the Issuers' compliance with any
of their covenants hereunder (as to which the Trustee is entitled to rely
exclusively on Officers' Certificates).

          SECTION 5.04.  Reports by Trustee. The Trustee shall transmit to
                         ------------------
Holders such reports concerning the Trustee and its actions under the Indenture
as may be required pursuant to the Trust Indenture Act at the time and in the
manner provided pursuant thereto.

          Reports pursuant to this Section 5.04 shall be transmitted by mail:

          (1)  to all Registered Holders, as the names and addresses of such
     Holders appear in the Debt Security Register; and

          (2)  except in the cases of reports under Section 313(b)(2) of the
     Trust Indenture Act, to each holder of a Debt Security of any series whose
     name and address appear in the information preserved at the time by the
     Trustee in accordance with Section 5.02.

          A copy of each report at the time of its mailing to Holders shall be
filed with the Commission and each stock exchange (if any) on which the Debt
Securities of any series are listed. The Issuers agree to notify promptly the
Trustee whenever the Debt Securities of any series become listed on any stock
exchange and of any delisting thereof.

          SECTION 5.05.  Record Dates for Action by Holders. If the Issuers
                         ----------------------------------
shall solicit from the Holders of Debt Securities of any series any action
(including the making of any demand or request, the giving of any direction,
notice, consent or waiver or the taking of any other action), the Issuers may,
at their option, by Board Resolutions, fix in advance a record date for the
determination of Holders of Debt Securities entitled to take such action, but
the Issuers shall have no obligation to do so. Any such record date shall be
fixed at the Issuers' discretion. If such a record date is fixed, such action
may be sought or given before or after the record date, but only the Holders of
Debt Securities of record at the close of business on such record date shall be
deemed to be Holders of Debt Securities for the purpose of determining whether
Holders of the requisite proportion of Debt Securities of such series
Outstanding have authorized or agreed or consented to such action, and for that
purpose the Debt Securities of such series Outstanding shall be computed as of
such record date.

                                       32
<PAGE>

                                  ARTICLE VI

            Remedies of the Trustee and Holders in Event of Default
            -------------------------------------------------------

          SECTION 6.01.  Events of Default.  If any one or more of the following
                         -----------------
shall have occurred and be continuing with respect to Debt Securities of any
series (each of the following, an "Event of Default"):

          (a)  the Issuers Default for a period of 60 days in the payment when
     due of interest on any Debt Securities of that series; or

          (b)  the Issuers default in the payment when due of principal of or
     premium, if any, on any Debt Securities of that series at maturity, upon
     redemption or otherwise; or

          (c)  default in the payment of any sinking fund payment with respect
     to any Debt Securities of that series as and when the same shall become due
     and payable; or

          (d)  failure on the part of the Issuers to comply with Article X; or

          (e)  failure by the Issuers for 30 days after notice to comply to duly
     observe or perform any other of the covenants or agreements on the part of
     the Issuers in the Debt Securities of that series in any Board Resolution
     authorizing the issuance of that series of Debt Securities, in the
     Indenture with respect to such series or in any supplemental Indenture with
     respect to such series (other than a covenant a default in the performance
     of which is elsewhere in this Section 6.01 specifically dealt with); or

          (f)  pursuant to or within the meaning of Bankruptcy Law, an Issuer
     commences a voluntary case, consents to the entry of an order for relief
     against it in an involuntary case, consents to the appointment of a
     custodian of it or for all or substantially all of its property, makes a
     general assignment for the benefit of its creditors, or generally is not
     paying its debts as they become due; or

          (g)  (i) a court of competent jurisdiction enters an order or decree
     under any Bankruptcy Law that is for relief against an Issuer in an
     involuntary case, appoints a custodian of an Issuer, or orders the
     liquidation of an Issuer and (ii) such order or decree remains unstayed and
     in effect for 60 consecutive days; or

          (h)  any other Event of Default provided under the terms of the Debt
     Securities of that series;

then and in each and every case that an Event of Default with respect to Debt
Securities of that series at the time outstanding occurs and is continuing,
either the Trustee or the Holders of at least 25% in aggregate principal amount
of the Debt Securities of that series, may declare the principal of (or, if the
Debt Securities of that series are Original Issue Discount Debt Securities, such
portion of the principal amount as may be specified in the terms of that series)
and interest on all the Debt Securities of that series to be due and payable
immediately.

                                       33
<PAGE>

          The Holders of a majority in principal amount of the Debt Securities
of a particular series by notice to the Trustee may rescind an acceleration and
its consequences if the rescission would not conflict with any judgment or
decree already rendered and if all existing Events of Default have been cured or
waived except nonpayment of principal or interest that has become due solely
because of acceleration. Upon any such rescission, the parties hereto shall be
restored respectively to their several positions and rights hereunder, and all
rights, remedies and powers of the parties hereto shall continue as though no
proceeding had been taken.

          In case the Trustee or any Holder shall have proceeded to enforce any
right under the Indenture and such proceedings shall have been discontinued or
abandoned because of such rescission or annulment or for any other reason or
shall have been determined adversely to the Trustee or such Holder, then and in
every such case the parties hereto shall be restored respectively to their
several positions and rights hereunder, and all rights, remedies and powers of
the parties hereto shall continue as though no such proceeding had been taken.

          The foregoing Events of Default shall constitute Events of Default
whatever the reason for any such Event of Default and whether it is voluntary or
involuntary or is effected by operation of law or pursuant to any judgment,
decree or order of any court or any order, rule or regulation of any
administrative or governmental body.

          The Issuers shall deliver to the Trustee, within 30 days after the
occurrence thereof, written notice in the form of an Officers' Certificate of
any event which with the giving of notice and the lapse of time would become an
Event of Default under clause (c), (d), (e), (f), (g) or (h), its status and
what action the Issuers are taking or propose to take with respect thereto.

          SECTION 6.02.  Collection of Indebtedness by Trustee, etc. If an Event
                         -------------------------------------------
of Default occurs and is continuing, the Trustee, in its own name and as trustee
of an express trust, shall be entitled and empowered to institute any action or
proceedings at law or in equity for the collection of the sums so due and unpaid
or enforce the performance of any provision of the Debt Securities of the
affected series or the Indenture, and may prosecute any such action or
proceedings to judgment or final decree, and may enforce any such judgment or
final decree against the Issuers or any other obligor upon the Debt Securities
of such series (and collect in the manner provided by law out of the property of
the Issuers or any other obligor upon the Debt Securities of such series
wherever situated the moneys adjudged or decreed to be payable).

          In case there shall be pending proceedings for the bankruptcy or for
the reorganization of either of the Issuers or any other obligor upon the Debt
Securities of any series under Title 11 of the United States Code or any other
Federal or State bankruptcy, insolvency or similar law, or in case a receiver,
trustee or other similar official shall have been appointed for its property, or
in case of any other similar judicial proceedings relative to either of the
Issuers or any other obligor upon the Debt Securities of any series, its
creditors or its property, the Trustee, irrespective of whether the principal of
Debt Securities of any series shall then be due and payable as therein expressed
or by declaration or otherwise and irrespective of whether the Trustee shall
have made any demand pursuant to the provisions of this Section 6.02, shall be
entitled and empowered, by intervention in such proceedings or otherwise, to
file and prove a claim or claims for the whole amount of principal, premium, if
any, and interest (or, if the Debt Securities of such series are Original Issue
Discount Debt Securities, such portion of the

                                       34
<PAGE>

principal amount as may be specified in the terms of such series) owing and
unpaid in respect of the Debt Securities of such series, and to file such other
papers or documents as may be necessary or advisable in order to have the claims
of the Trustee (including any claim for reasonable compensation to the Trustee,
its agents, attorneys and counsel, and for reimbursement of all expenses and
liabilities incurred, and all advances made, by the Trustee except as a result
of its negligence or bad faith) and of the Holders thereof allowed in any such
judicial proceedings relative to either of the Issuers, or any other obligor
upon the Debt Securities of such series, its creditors or its property, and to
collect and receive any moneys or other property payable or deliverable on any
such claims, and to distribute all amounts received with respect to the claims
of such Holders and of the Trustee on their behalf, and any receiver, assignee
or trustee in bankruptcy or reorganization is hereby authorized by each of such
Holders to make payments to the Trustee, and, in the event that the Trustee
shall consent to the making of payments directly to such Holders, to pay to the
Trustee such amount as shall be sufficient to cover reasonable compensation to
the Trustee, its agents, attorneys and counsel, and all other reasonable
expenses and liabilities incurred, and all advances made, by the Trustee except
as a result of its negligence or bad faith.

          All rights of action and of asserting claims under the Indenture, or
under any of the Debt Securities, of any series, may be enforced by the Trustee
without the possession of any such Debt Securities or the production thereof in
any trial or other proceedings relative thereto, and any such action or
proceedings instituted by the Trustee shall be brought in its own name as
trustee of an express trust, and any recovery of judgment (except for any
amounts payable to the Trustee pursuant to Section 7.06) shall be for the
ratable benefit of the Holders of all the Debt Securities in respect of which
such action was taken.

          In case of an Event of Default hereunder the Trustee may in its
discretion proceed to protect and enforce the rights vested in it by the
Indenture by such appropriate judicial proceedings as the Trustee shall deem
necessary to protect and enforce any of such rights, either at law or in equity
or in bankruptcy or otherwise, whether for the specific enforcement of any
covenant or agreement contained in the Indenture or in aid of the exercise of
any power granted in the Indenture, or to enforce any other legal or equitable
right vested in the Trustee by the Indenture or by law.

          SECTION 6.03.  Application of Moneys Collected by Trustee. Any moneys
                         ------------------------------------------
or other property collected by the Trustee pursuant to Section 6.02 with respect
to Debt Securities of any series shall be applied, in the order following, at
the date or dates fixed by the Trustee for the distribution of such moneys or
other property, upon presentation of the several Debt Securities of such series
in respect of which moneys or other property have been collected, and the
notation thereon of the payment, if only partially paid, and upon surrender
thereof if fully paid:

          First:  To the payment of all money due the Trustee pursuant to
          -----
     Section 7.06;

          Second:  In case the principal of the Outstanding Debt Securities in
          ------
     respect of which such moneys have been collected shall not have become due,
     to the payment of interest on the Debt Securities of such series in the
     order of the maturity of the installments of such interest, with interest
     (to the extent that such interest has been

                                       35
<PAGE>

     collected by the Trustee) upon the overdue installments of interest at the
     rate or Yield to Maturity (in the case of Original Issue Discount Debt
     Securities) specified in the Debt Securities of such series, such payments
     to be made ratably to the Persons entitled thereto, without discrimination
     or preference;

          Third:  In case the principal of the Outstanding Debt Securities in
          -----
     respect of which such moneys have been collected shall have become due, by
     declaration or otherwise, to the payment of the whole amount then owing and
     unpaid upon the Debt Securities of such series for principal and premium,
     if any, and interest, with interest on the overdue principal and premium,
     if any, and (to the extent that such interest has been collected by the
     Trustee) upon overdue installments of interest at the rate or Yield to
     Maturity (in the case of Original Issue Discount Debt Securities) specified
     in the Debt Securities of such series; and, in case such moneys shall be
     insufficient to pay in full the whole amount so due and unpaid upon the
     Debt Securities of such series, then to the payment of such principal and
     premium, if any, and interest, without preference or priority of principal
     and premium, if any, over interest, or of interest over principal and
     premium, if any, or of any installment of interest over any other
     installment of interest, or of any Debt Security of such series over any
     Debt Security of such series, ratably to the aggregate of such principal
     and premium, if any, and interest; and

          Fourth:  The remainder, if any, shall be paid to the Issuers, their
          ------
     successors or assigns, or as a court of competent jurisdiction may direct.

          The Trustee may fix a record date and payment date for any payment to
Holders pursuant to this Section 6.03. At least 15 days before such record date,
the Issuers shall mail to each Holder and the Trustee a notice that states the
record date, the payment date and amount to be paid.

          SECTION 6.04.  Limitation on Suits by Holders. No Holder of any Debt
                         ------------------------------
Security of any series shall have any right by virtue or by availing of any
provision of the Indenture to institute any action or proceeding at law or in
equity or in bankruptcy or otherwise, upon or under or with respect to the
Indenture, or for the appointment of a receiver or trustee, or for any other
remedy hereunder, unless such Holder previously shall have given to the Trustee
written notice of an Event of Default with respect to Debt Securities of that
same series and of the continuance thereof and unless the Holders of not less
than 25% in aggregate principal amount of the Outstanding Debt Securities of
that series shall have made written request upon the Trustee to institute such
action or proceedings in respect of such Event of Default in its own name as
Trustee hereunder and shall have offered to the Trustee such reasonable
indemnity as it may require against the costs, expenses and liabilities to be
incurred therein or thereby, and the Trustee, for 60 days after its receipt of
such notice, request and offer of indemnity shall have failed to institute any
such action or proceedings and no direction inconsistent with such written
request shall have been given to the Trustee pursuant to Section 6.06; it being
understood and intended, and being expressly covenanted by the Holder of every
Debt Security with every other Holder and the Trustee, that no one or more
Holders shall have any right in any manner whatever by virtue or by availing of
any provision of the Indenture to affect, disturb or prejudice the rights of any
Holders, or to obtain or seek to obtain priority over or preference to any other
such Holder, or to enforce any right under the Indenture, except in the manner
herein provided and for

                                       36
<PAGE>

the equal, ratable and common benefit of all such Holders. For the protection
and enforcement of the provisions of this Section 6.04, each and every Holder
and the Trustee shall be entitled to such relief as can be given either at law
or in equity.

          Notwithstanding any other provision in the Indenture, however, the
right of any Holder of any Debt Security to receive payment of the principal of,
and premium, if any, and (subject to Section 2.12) interest on, such Debt
Security on or after the respective due dates expressed in such Debt Security,
and to institute suit for the enforcement of any such payment on or after such
respective dates, shall not be impaired or effected without the consent of such
Holder.

          SECTION 6.05.  Remedies Cumulative; Delay or Omission in Exercise of
                         -----------------------------------------------------
Rights Not a Waiver of Default. All powers and remedies given by this Article VI
------------------------------
to the Trustee or to the Holders shall, to the extent permitted by law, be
deemed cumulative and not exclusive of any thereof or of any other powers and
remedies available to the Trustee or the Holders, by judicial proceedings or
otherwise, to enforce the performance or observance of the covenants and
agreements contained in the Indenture, and no delay or omission of the Trustee
or of any Holder to exercise any right or power accruing upon any Default
occurring and continuing as aforesaid, shall impair any such right or power, or
shall be construed to be a waiver of any such Default or an acquiescence
therein; and, subject to the provisions of Section 6.04, every power and remedy
given by this Article VI or by law to the Trustee or to the Holders may be
exercised from time to time, and as often as shall be deemed expedient, by the
Trustee or by the Holders.

          SECTION 6.06.  Rights of Holders of Majority in Principal Amount of
                         ----------------------------------------------------
Debt Securities to Direct Trustee and to Waive Default. The Holders of a
------------------------------------------------------
majority in aggregate principal amount of the Debt Securities of any series at
the time Outstanding shall have the right to direct the time, method, and place
of conducting any proceeding for any remedy available to the Trustee, or
exercising any trust or power conferred on the Trustee, with respect to the Debt
Securities of such series; provided, however, that such direction shall not be
                           --------  -------
otherwise than in accordance with law and the provisions of the Indenture, and
that subject to the provisions of Section 7.01, the Trustee shall have the right
to decline to follow any such direction if the Trustee being advised by counsel
shall determine that the action so directed may not lawfully be taken, or if the
Trustee shall by a Responsible Officer or officers determine that the action so
directed would involve it in personal liability or would be prejudicial to
Holders of Debt Securities of such series not taking part in such direction; and
provided further, however, that nothing in the Indenture contained shall impair
-------- -------  -------
the right of the Trustee to take any action deemed proper by the Trustee and
which is not inconsistent with such direction by such Holders. Prior to the
acceleration of the maturity of the Debt Securities of any series, as provided
in Section 6.01, the Holders of a majority in aggregate principal amount of the
Debt Securities of that series at the time Outstanding by notice to the Trustee
may on behalf of the Holders of all the Debt Securities of that series waive any
past Default or Event of Default and its consequences for that series specified
in the terms thereof as contemplated by Section 2.03, except (i) a Default in
the payment of the principal of, and premium, if any, or interest on, any of the
Debt Securities and (ii) a Default in respect of a provision that under Section
9.02 cannot be amended, supplemented or waived without the consent of each
Holder affected thereby. In case of any such waiver, such Default shall cease to
exist, any Event of Default arising therefrom shall be deemed to have been cured
for every purpose of the Indenture, and the Issuers, the Trustee and the Holders
of the Debt

                                       37
<PAGE>

Securities of that series shall be restored to their former positions and rights
hereunder, respectively; but no such waiver shall extend to any subsequent or
other Default or impair any right consequent thereon.

          SECTION 6.07.  Trustee to Give Notice of Defaults Known to It, but May
                         -------------------------------------------------------
Withhold Such Notice in Certain Circumstances. The Trustee shall, within 90 days
---------------------------------------------
after the occurrence of a Default known to it with respect to a series of Debt
Securities give to the Holders thereof, in the manner provided in Section 12.03,
notice of all Defaults with respect to such series known to the Trustee, unless
such Defaults shall have been cured or waived before the giving of such notice;
provided that, except in the case of Default in the payment of the principal of,
--------
or premium, if any, or interest on, any of the Debt Securities of such series or
in the making of any sinking fund payment with respect to the Debt Securities of
such series, the Trustee shall be protected in withholding such notice if and so
long as the committee of Responsible Officers of the Trustee in good faith
determine that the withholding of such notice is in the interests of the Holders
thereof.

          SECTION 6.08.  Requirement of an Undertaking To Pay Costs in Certain
                         -----------------------------------------------------
Suits under the Indenture or Against the Trustee. All parties to the Indenture
------------------------------------------------
agree, and each Holder of any Debt Security by his acceptance thereof shall be
deemed to have agreed, that any court may in its discretion require, in any suit
for the enforcement of any right or remedy under the Indenture, or in any suit
against the Trustee for any action taken or omitted by it as Trustee, the filing
by any party litigant in such suit of an undertaking to pay the costs of such
suit in the manner and to the extent provided in the Trust Indenture Act, and
that such court may in its discretion assess reasonable costs, including
reasonable attorneys' fees and expenses, against any party litigant in such
suit, having due regard to the merits and good faith of the claims or defenses
made by such party litigant; but the provisions of this Section 6.08 shall not
apply to any suit instituted by the Trustee, to any suit instituted by any
Holder, or group of Holders, holding in the aggregate more than ten percent in
principal amount of the Outstanding Debt Securities of that series or to any
suit instituted by any Holder for the enforcement of the payment of the
principal of, or premium, if any, or interest on, any Debt Security on or after
the due date for such payment expressed in such Debt Security.

                                  ARTICLE VII

                            Concerning the Trustee
                            ----------------------

          SECTION 7.01.  Certain Duties and Responsibilities. The Trustee, prior
                         -----------------------------------
to the occurrence of an Event of Default and after the curing or waiving of all
Events of Default which may have occurred, undertakes to perform such duties and
only such duties as are specifically set forth in the Indenture. In case an
Event of Default has occurred (which has not been cured or waived), the Trustee
shall exercise such of the rights and powers vested in it by the Indenture, and
use the same degree of care and skill in their exercise, as a prudent person
would exercise or use under the circumstances in the conduct of his own affairs.

          No provision of the Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct, except that:

                                       38
<PAGE>

          (a)  this subsection shall not be construed to limit the effect of the
     first paragraph of this Section 7.01;

          (b)  prior to the occurrence of an Event of Default with respect to
     the Debt Securities of a series and after the curing or waiving of all
     Events of Default with respect to such series which may have occurred:

               (1)  the duties and obligations of the Trustee with respect to
          Debt Securities of any series shall be determined solely by the
          express provisions of the Indenture, and the Trustee shall not be
          liable except for the performance of such duties and obligations with
          respect to such series as are specifically set forth in the Indenture,
          and no implied covenants or obligations with respect to such series
          shall be read into the Indenture against the Trustee; and

               (2)  in the absence of bad faith on the part of the Trustee, the
          Trustee may conclusively rely, as to the truth of the statements and
          the correctness of the opinions expressed therein, upon any
          certificates or opinions furnished to the Trustee and conforming to
          the requirements of the Indenture; but in the case of any such
          certificates or opinions which by any provision hereof are
          specifically required to be furnished to the Trustee, the Trustee
          shall be under a duty to examine the same to determine whether or not
          they conform to the requirements of the Indenture;

          (c)  the Trustee shall not be liable for an error of judgment made in
     good faith by a Responsible Officer, unless it shall be proved that the
     Trustee was negligent in ascertaining the pertinent facts; and

          (d)  the Trustee shall not be liable with respect to any action taken
     or omitted to be taken by it with respect to Debt Securities of any series
     in good faith in accordance with the direction of the Holders of not less
     than a majority in aggregate principal amount of the Outstanding Debt
     Securities of that series relating to the time, method and place of
     conducting any proceeding for any remedy available to the Trustee, or
     exercising any trust or power conferred upon the Trustee, under the
     Indenture with respect to Debt Securities of such series.

          None of the provisions of the Indenture shall require the Trustee to
expend or risk its own funds or otherwise incur any personal financial liability
in the performance of any of its duties hereunder, or in the exercise of any of
its rights or powers, if there shall be reasonable grounds for believing that
repayment of such funds or adequate indemnity against such risk or liability is
not reasonably assured to it.

          Whether or not therein expressly so provided, every provision of the
Indenture relating to the conduct or affecting the liability of or affording
protection to the Trustee shall be subject to the provisions of this Section.

                                       39
<PAGE>

          SECTION 7.02.  Certain Rights of Trustee. Except as otherwise provided
                         -------------------------
 in Section 7.01:

          (a)  the Trustee may conclusively rely and shall be fully protected in
     acting or refraining from acting upon any resolution, certificate,
     statement, instrument, opinion, report, notice, request, direction,
     consent, order, bond, debenture, note or other paper or document (whether
     in its original or facsimile form) believed by it to be genuine and to have
     been signed or presented by the proper party or parties;

          (b)  any request, direction, order or demand of the Issuers mentioned
     herein shall be sufficiently evidenced by an Issuer Order (unless other
     evidence in respect thereof be herein specifically prescribed); and any
     Board Resolution may be evidenced to the Trustee by a copy thereof
     certified by the Secretary or an Assistant Secretary of each of the
     Managing General Partner and PAA Finance;

          (c)  the Trustee may consult with counsel of its own selection, and
     the advice of such counsel or any Opinion of Counsel shall be full and
     complete authorization and protection in respect of any action taken or
     suffered or omitted by it hereunder in good faith and in accordance with
     such advice or Opinion of Counsel;

          (d)  the Trustee shall be under no obligation to exercise any of the
     rights or powers vested in it by the Indenture at the request, order or
     direction of any of the Holders of Debt Securities of any series pursuant
     to the provisions of the Indenture, unless such Holders shall have offered
     to the Trustee security or indemnity reasonably satisfactory to it against
     the costs, expenses and liabilities which may be incurred therein or
     thereby;

          (e)  the Trustee shall not be liable for any action taken or omitted
     by it in good faith and reasonably believed by it to be authorized or
     within the discretion or rights or powers conferred upon it by the
     Indenture;

          (f)  prior to the occurrence of an Event of Default and after the
     curing of all Events of Default which may have occurred, the Trustee shall
     not be bound to make any investigation into the facts or matters stated in
     any resolution, certificate, statement, instrument, opinion, report,
     notice, request, direction, consent, order, approval or other paper or
     document, unless requested in writing to do so by the Holders of a majority
     in aggregate principal amount of the then outstanding Debt Securities of a
     series affected by such matter; provided, however, that if the payment
                                     --------  -------
     within a reasonable time to the Trustee of the costs, expenses or
     liabilities likely to be incurred by it in the making of such investigation
     is not, in the opinion of the Trustee, reasonably assured to the Trustee by
     the security afforded to it by the terms of the Indenture, the Trustee may
     require indemnity reasonably satisfactory to it against such costs,
     expenses or liabilities as a condition to so proceeding; the Trustee shall
     be entitled to examine the books, records and premises of the Issuers
     during ordinary business hours and for any purpose relevant to the
     Indenture, personally or by an agent or attorney at the sole cost of the
     Issuers and shall incur no liability or additional liability of any kind by
     reason of such inquiry or investigation;

                                       40
<PAGE>

                  (g) the Trustee may execute any of the trusts or powers
         hereunder or perform any duties hereunder either directly or by or
         through agents or attorneys and the Trustee shall not be responsible
         for any misconduct or negligence on the part of any agent or attorney
         appointed by it with due care hereunder;

                  (h) if any property other than cash shall at any time be
         subject to a Lien in favor of the Holders, the Trustee, if and to the
         extent authorized by a receivership or bankruptcy court of competent
         jurisdiction or by the supplemental instrument subjecting such property
         to such Lien, shall be entitled to make advances for the purpose of
         preserving such property or of discharging tax Liens or other prior
         Liens or encumbrances thereon; and

                  (i) the Trustee shall not be deemed to have notice of any
         Default or Event of Default unless a Responsible Officer of the Trustee
         has actual knowledge thereof or unless written notice of any event
         which is in fact such a Default is received by the Trustee at the
         Corporate Trust Office of the Trustee, and such notice references the
         Debt Securities and the Indenture; and

                  (j) the rights, privileges, protections, immunities and
         benefits given to the Trustee, including, without limitation, its right
         to be indemnified, are extended to, and shall be enforceable by, the
         Trustee in each of its capacities hereunder, and to each agent,
         custodian and other Person employed by the Trustee to act hereunder.

                  SECTION 7.03. Trustee Not Liable for Recitals in Indenture or
                                -----------------------------------------------
in Debt Securities. The recitals contained herein and in the Debt Securities
------------------
(except the Trustee's certificate of authentication) shall be taken as the
statements of the Issuers, and the Trustee assumes no responsibility for the
correctness of the same. The Trustee makes no representations as to the validity
or sufficiency of the Indenture or of the Debt Securities of any series, except
that the Trustee represents that it is duly authorized to execute and deliver
the Indenture, authenticate the Debt Securities and perform its obligations
hereunder, and that the statements made by it or to be made by it in a Statement
of Eligibility and Qualification on Form T-1 supplied to the Issuers are true
and accurate. The Trustee shall not be accountable for the use or application by
the Issuers of any of the Debt Securities or of the proceeds thereof.

                  SECTION 7.04. Trustee, Paying Agent or Registrar May Own Debt
                                -----------------------------------------------
Securities. The Trustee or any paying agent or Registrar, in its individual or
----------
any other capacity, may become the owner or pledgee of Debt Securities and
subject to the provisions of the Trust Indenture Act relating to conflicts of
interest and preferential claims may otherwise deal with the Issuers with the
same rights it would have if it were not Trustee, paying agent or Registrar;
provided, however, that if the Trustee acquires any such conflicting interest
and an Event of Default or Default has occurred and is continuing, the Trustee
must eliminate such conflict within 90 days, apply to the Commission for
permission to continue as trustee or resign.

                  SECTION 7.05. Moneys Received by Trustee to Be Held in Trust.
                                ----------------------------------------------
Subject to the provisions of Section 11.02, all moneys received by the Trustee
shall, until used or applied as herein provided, be held in trust for the
purposes for which they were received, but need not be segregated from other
funds except to the extent required by law. The Trustee shall be under no

                                       41
<PAGE>

liability for interest on any moneys received by it hereunder. So long as no
Event of Default shall have occurred and be continuing, all interest allowed
on any such moneys shall be paid from time to time to the Issuers upon an
Issuer Order.

                  SECTION 7.06. Compensation and Reimbursement. The Issuers
                                ------------------------------
covenant and agree to pay in Dollars to the Trustee from time to time, and the
Trustee shall be entitled to, reasonable compensation for all services rendered
by it hereunder (which shall not be limited by any provision of law in regard to
the compensation of a trustee of an express trust), and, except as otherwise
expressly provided herein, the Issuers will pay or reimburse in Dollars the
Trustee upon its request for all expenses, disbursements and advances incurred
or made by the Trustee in accordance with any of the provisions of the Indenture
(including the reasonable compensation and the expenses and disbursements of its
agents, attorneys and counsel and of all Persons not regularly in its employ)
except any such expense, disbursement or advances as may arise from its
negligence or bad faith. The Issuers also covenant to fully indemnify in Dollars
the Trustee and any predecessor Trustee for, and to hold it harmless against,
any and all loss, liability, claim, damage or expense incurred without
negligence or willful misconduct on the part of the Trustee, arising out of or
in connection with the acceptance or administration of this trust or trusts
hereunder, including the costs and expenses of defending itself against any
claim of liability in connection with the exercise or performance of any of its
powers or duties hereunder. The obligations of the Issuers under this Section
7.06 to compensate and indemnify the Trustee and to pay or reimburse the Trustee
for expenses, disbursements and advances shall constitute additional
indebtedness hereunder and shall survive the satisfaction and discharge of the
Indenture. The Issuers and the Holders agree that such additional indebtedness
shall be secured by a Lien prior to that of the Debt Securities upon all
property and funds held or collected by the Trustee, as such, except funds held
in trust for the payment of principal of, and premium, if any, or interest on,
particular Debt Securities.

                  When the Trustee incurs expenses or renders services after an
Event of Default specified in Section 6.01(g) or (h) occurs, the expenses and
the compensation for the services are intended to constitute expenses of
administration under any bankruptcy, insolvency, reorganization or other similar
law.

                  SECTION 7.07. Right of Trustee to Rely on an Officers'
                                ----------------------------------------
Certificate Where No Other Evidence Specifically Prescribed. Except as otherwise
-----------------------------------------------------------
provided in Section 7.01, whenever in the administration of the provisions of
the Indenture the Trustee shall deem it necessary or desirable that a matter be
proved or established prior to taking or suffering or omitting any action
hereunder, such matter (unless other evidence in respect thereof be herein
specifically prescribed) may, in the absence of negligence or bad faith on the
part of the Trustee, be deemed to be conclusively proved and established by an
Officers' Certificate delivered to the Trustee and such certificate, in the
absence of negligence or bad faith on the part of the Trustee, shall be full
warrant to the Trustee for any action taken, suffered or omitted by it under the
provisions of the Indenture upon the faith thereof.

                  SECTION 7.08. Separate Trustee; Replacement of Trustee. The
                                ----------------------------------------
Issuers may, but need not, appoint a separate Trustee for any one or more series
of Debt Securities. The Trustee may resign with respect to one or more or all
series of Debt Securities at any time by giving notice to the Issuers. The
Holders of a majority in principal amount of the Debt Securities

                                       42
<PAGE>

of a particular series may remove the Trustee for such series and only such
series by so notifying the Trustee and may appoint a successor Trustee. The
Issuers shall remove the Trustee if:

                  (1)  the Trustee fails to comply with Section 7.10;

                  (2)  the Trustee is adjudged bankrupt or insolvent;

                  (3)  a receiver or other public officer takes charge of the
          Trustee or its property; or

                  (4)  the Trustee otherwise becomes incapable of acting.

                  If the Trustee resigns, is removed by the Issuers or by the
Holders of a majority in principal amount of the Debt Securities of a particular
series and such Holders do not reasonably promptly appoint a successor Trustee,
or if a vacancy exists in the office of Trustee for any reason (the Trustee in
such event being referred to herein as the retiring Trustee), the Issuers shall
promptly appoint a successor Trustee. No resignation or removal of the Trustee
and no appointment of a successor Trustee shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of this Section 7.08.

                  A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Issuers. Thereupon the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under the Indenture. The successor Trustee shall mail a notice of its succession
to Holders of Debt Securities of each applicable series. The retiring Trustee
shall promptly transfer all property held by it as Trustee to the successor
Trustee, subject to the Lien provided for in Section 7.06.

                  If a successor Trustee does not take office within 60 days
after the retiring Trustee gives notice of resignation or is removed, the
retiring Trustee or the Holders of 25% in principal amount of the Debt
Securities of any applicable series may petition any court of competent
jurisdiction for the appointment of a successor Trustee for the Debt Securities
of such series.

                  If the Trustee fails to comply with Section 7.10, any Holder
of Debt Securities of any applicable series may petition at the expense of the
Issuers any court of competent jurisdiction for the removal of the Trustee and
the appointment of a successor Trustee for the Debt Securities of such series.
                  Notwithstanding the replacement of the Trustee pursuant to
this Section 7.08, the Issuers' obligations under Section 7.06 shall continue
for the benefit of the retiring Trustee.

                  In the case of the appointment hereunder of a separate or
successor Trustee with respect to the Debt Securities of one or more series, the
Issuers, any retiring Trustee and each successor or separate Trustee with
respect to the Debt Securities of any applicable series shall execute and
deliver an Indenture supplemental hereto (1) which shall contain such provisions
as shall be deemed necessary or desirable to confirm that all the rights,
powers, trusts and duties of any retiring Trustee with respect to the Debt
Securities of any series as to which any such retiring Trustee is not retiring
shall continue to be vested in such retiring Trustee and (2) that shall add to

                                       43
<PAGE>

or change any of the provisions of the Indenture as shall be necessary to
provide for or facilitate the administration of the trusts hereunder by more
than one trustee, it being understood that nothing herein or in such
supplemental Indenture shall constitute such Trustees co-trustees of the same
trust and that each such separate, retiring or successor Trustee shall be
Trustee of a trust or trusts hereunder separate and apart from any trust or
trusts hereunder administered by any other such Trustee.

                  SECTION 7.09. Successor Trustee by Merger. If the Trustee
                                ---------------------------
consolidates with, merges or converts into, or transfers all or substantially
all of its corporate trust business or assets to, another corporation or banking
association, the resulting, surviving or transferee corporation or banking
association without any further act shall be the successor Trustee, provided
such Person shall be otherwise qualified and eligible under this Article VII,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto. As soon as practicable, the successor Trustee shall
mail a notice of its succession to the Issuers and the Holders of the Debt
Securities then Outstanding.

                  In case at the time such successor or successors by merger,
conversion or consolidation to the Trustee shall succeed to the trusts created
by the Indenture any of the Debt Securities shall have been authenticated but
not delivered, any such successor to the Trustee may adopt the certificate of
authentication of any predecessor trustee, and deliver such Debt Securities so
authenticated; and in case at that time any of the Debt Securities shall not
have been authenticated, any successor to the Trustee may authenticate such Debt
Securities either in the name of any predecessor hereunder or in the name of the
successor to the Trustee; and in all such cases such certificates shall have the
full force which it is anywhere in the Debt Securities or in the Indenture
provided that the certificate of the Trustee shall have.

                  SECTION 7.10. Eligibility; Disqualification. The Trustee shall
                                -----------------------------
at all times satisfy the requirements of Section 310(a) of the Trust Indenture
Act. The Trustee shall have a combined capital and surplus of at least
$50,000,000, as set forth in its most recently published annual report of
condition. No obligor upon the Debt Securities of a particular series or Person
directly or indirectly controlling, controlled by or under common control with
such obligor shall serve as Trustee upon the Debt Securities of such series. The
Trustee shall comply with Section 310(b) of the Trust Indenture Act; provided,
                                                                     --------
however, that there shall be excluded from the operation of Section 310(b)(1) of
-------
the Trust Indenture Act the Indenture or any indenture or indentures under which
other securities or certificates of interest or participation in other
securities of the Issuers are outstanding if the requirements for such exclusion
set forth in Section 310(b)(1) of the Trust Indenture Act are met.

                  SECTION 7.11. Preferential Collection of Claims Against
                                -----------------------------------------
Issuers. The Trustee shall comply with Section 311(a) of the Trust Indenture
-------
Act, excluding any creditor relationship listed in Section 311(b) of the Trust
Indenture Act. A Trustee who had resigned or been removed shall be subject to
Section 311(a) of the Trust Indenture Act to the extent indicated therein.

                  SECTION 7.12. Compliance with Tax Laws. The Trustee hereby
                                ------------------------
agrees to comply with all U.S. Federal income tax information reporting and
withholding requirements applicable to it with respect to payments of principal,
premium (if any) and interest on the Debt

                                       44
<PAGE>

Securities, whether acting as Trustee, Security Registrar, paying agent or
otherwise with respect to the Debt Securities.

                                 ARTICLE VIII

                            Concerning the Holders
                            ----------------------

                  SECTION 8.01. Evidence of Action by Holders. Whenever in the
                                -----------------------------
Indenture it is provided that the Holders of a specified percentage in aggregate
principal amount of the Debt Securities of any or all series may take action
(including the making of any demand or request, the giving of any direction,
notice, consent or waiver or the taking of any other action) the fact that at
the time of taking any such action the Holders of such specified percentage have
joined therein may be evidenced (a) by any instrument or any number of
instruments of similar tenor executed by Holders in person or by agent or proxy
appointed in writing, (b) by the record of the Holders voting in favor thereof
at any meeting of Holders duly called and held in accordance with the provisions
of Section 5.02 or (c) by a combination of such instrument or instruments and
any such record of such a meeting of Holders.

                  SECTION 8.02. Proof of Execution of Instruments and of Holding
                                ------------------------------------------------
of Debt Securities. Subject to the provisions of Sections 7.01, 7.02 and 12.09,
------------------
proof of the execution of any instrument by a Holder or his agent or proxy shall
be sufficient if made in accordance with such reasonable rules and regulations
as may be prescribed by the Trustee or in such manner as shall be satisfactory
to the Trustee.

                  The ownership of Registered Securities of any series shall be
proved by the Debt Security Register or by a certificate of the Registrar for
such series.

                  The Trustee may require such additional proof of any matter
referred to in this Section 8.02 as it shall deem necessary.

                  SECTION 8.03. Who May Be Deemed Owner of Debt Securities.
                                ------------------------------------------
Prior to due presentment for registration of transfer of any Registered
Security, the Issuers, the Trustee, any paying agent and any Registrar may
deem and treat the Person in whose name any Registered Security shall be
registered upon the books of the Issuers as the absolute owner of such
Registered Security (whether or not such Registered Security shall be overdue
and notwithstanding any notation of ownership or other writing thereon) for
the purpose of receiving payment of or on account of the principal of and
premium, if any, and (subject to Section 2.12) interest on such Registered
Security and for all other purposes, and neither the Issuers nor the Trustee
nor any paying agent nor any Registrar shall be affected by any notice to the
contrary; and all such payments so made to any such Holder for the time
being, or upon his order, shall be valid and, to the extent of the sum or
sums so paid, effectual to satisfy and discharge the liability for moneys
payable upon any such Registered Security.

                  SECTION 8.04. Instruments Executed by Holders Bind Future
                                -------------------------------------------
Holders. At any time prior to (but not after) the evidencing to the Trustee, as
-------
provided in Section 8.01, of the taking of any action by the Holders of the
percentage in aggregate principal amount of the Debt Securities of any series
specified in the Indenture in connection with such action and subject to

                                       45
<PAGE>

the following paragraph, any Holder of a Debt Security which is shown by the
evidence to be included in the Debt Securities the Holders of which have
consented to such action may, by filing written notice with the Trustee at its
Corporate Trust Office of the Trustee and upon proof of holding as provided in
Section 8.02, revoke such action so far as concerns such Debt Security. Except
as aforesaid any such action taken by the Holder of any Debt Security shall be
conclusive and binding upon such Holder and upon all future Holders and owners
of such Debt Security and of any Debt Security issued upon transfer thereof or
in exchange or substitution therefor, irrespective of whether or not any
notation in regard thereto is made upon such Debt Security or such other Debt
Securities. Any action taken by the Holders of the percentage in aggregate
principal amount of the Debt Securities of any series specified in the Indenture
in connection with such action shall be conclusively binding upon the Issuers,
the Trustee and the Holders of all the Debt Securities of such series.

                  The Issuers may, but shall not be obligated to, fix a record
date for the purpose of determining the Holders of Registered Securities
entitled to give their consent or take any other action required or permitted to
be taken pursuant to the Indenture. If a record date is fixed, then
notwithstanding the immediately preceding paragraph, those Persons who were
Holders of Registered Securities at such record date (or their duly designated
proxies), and only those Persons, shall be entitled to give such consent or to
revoke any consent previously given or to take any such action, whether or not
such Persons continue to be Holders of Registered Securities after such record
date. No such consent shall be valid or effective for more than 120 days after
such record date unless the written consent of the Holders of the percentage in
aggregate principal amount of the Debt Securities of such series specified in
the Indenture shall have been received within such 120-day period.

                                  ARTICLE IX

                       Amendment, Supplement and Waiver
                       --------------------------------

                  SECTION 9.01. Without Consent of Holders of Debt Securities.
                                ---------------------------------------------
The Issuers and the Trustee may from time to time and at any time, without the
consent of Holders, enter into an Indenture or Indentures supplemental hereto
(which shall conform to the provisions of the Trust Indenture Act as in force at
the date of the execution thereof) for one or more of the following purposes:

                  (a)  to cure any ambiguity, defect or inconsistency contained
         herein, in any supplemental Indenture or in the Debt Securities of such
         series;

                  (b)  to provide for uncertificated Debt Securities in addition
         to or in place of certificated Debt Securities; provided, however, that
                                                         --------  -------
         the uncertificated Debt Securities are issued in registered form for
         purposes of Section 163(f) of the Code, or in a manner such that the
         uncertificated Debt Securities are described in Section 163(f)(2)(B) of
         the Code;

                  (c)  to provide for the assumption of an Issuer's obligations
         to Holders pursuant to Article X;

                                       46
<PAGE>

                  (d)  to add guarantors with respect to the Debt Securities as
         parties to the Indenture or to release guarantors in accordance with
         the provisions of any supplemental Indenture;

                  (e)  to make any changes that would provide any additional
         rights or benefits to the Holders of the Debt Securities or that do
         not, taken as a whole, adversely affect the legal rights hereunder of
         any Holder;

                  (f)  to comply with the requirements of the Commission to
         permit the qualification of the Indenture or any Indenture supplemental
         hereto under the Trust Indenture Act as then in effect, except that
         nothing herein contained shall permit or authorize the inclusion in any
         Indenture supplemental hereto of the provisions referred to in Section
         316(a)(2) of the Trust Indenture Act;

                  (g)  to evidence or provide for the acceptance of appointment
         hereunder by a successor or separate Trustee with respect to the Debt
         Securities of one or more series and to add to or change any of the
         provisions of the Indenture as shall be necessary to provide for or
         facilitate the administration of the trusts hereunder by more than one
         Trustee;

                  (h)  to add any additional Events of Default;

                  (i)  to secure the Debt Securities and/or any guarantee with
         respect to any Debt Securities; and

                  (j)  to establish the form or terms of the Debt Securities as
         permitted by Section 2.01 or 2.03.

                  The Trustee is hereby authorized to join with the Issuers and
guarantors with respect to any Debt Securities in the execution of any such
supplemental Indenture, to make any further appropriate agreements and
stipulations which may be therein contained and to accept the conveyance,
transfer, assignment, mortgage or pledge of any property thereunder, but the
Trustee shall not be obligated to enter into any such supplemental Indenture
which affects the Trustee's own rights, duties or immunities under the Indenture
or otherwise.

                  Any supplemental Indenture authorized by the provisions of
this Section 9.01 may be executed by the Issuers, any guarantors with respect to
any Debt Securities and the Trustee without the consent of the Holders of any of
the Debt Securities at the time outstanding, notwithstanding any of the
provisions of Section 9.02.

                  After an amendment under this Section 9.01 becomes effective,
the Issuers shall mail to Holders of Debt Securities of each series affected
thereby a notice briefly describing such amendment. The failure to give such
notice to all such Holders, or any defect therein, shall not impair or affect
the validity of an amendment under this Section 9.01.

                  SECTION 9.02. With Consent of Holders of Debt Securities.
                                ------------------------------------------
Without notice to any Holder but with the consent (evidenced as provided in
Section 8.01) of the Holders of a majority in aggregate principal amount of the
outstanding Debt Securities of each series affected

                                       47
<PAGE>

by such supplemental Indenture, (a) the Issuers, when authorized by Board
Resolutions, and the Trustee may from time to time and at any time enter into an
Indenture or Indentures supplemental hereto (which shall conform to the
provisions of the Trust Indenture Act as in force at the date of execution
thereof) for the purpose of adding any provisions to or changing in any manner
or eliminating any of the provisions of the Indenture or of any supplemental
Indenture or of modifying in any manner the rights of the Holders of the Debt
Securities of such series, and (b) subject to the Sections 6.04 and 6.08, any
existing Default or Events of Default or compliance with any provision of the
Indenture or the Debt Securities of such series may be waived; provided, that no
                                                               --------
such supplemental Indenture or waiver, without the consent of the Holders of
each Debt Security so affected, shall (i) reduce the percentage in principal
amount of Debt Securities of any series whose Holders must consent to an
amendment, supplement or waiver; (ii) reduce the principal of or change the
Stated Maturity of any Debt Security; (iii) reduce or waive the premium payable
upon the redemption of any Debt Security or alter or waive any provisions by
which any Debt Security may or shall be redeemed in accordance with Article III
(other than provisions requiring the repurchase of the Debt Securities of such
series if so permitted by the Board Resolutions or supplemental Indenture
establishing the terms of such series); (iv) reduce the rate of or change the
time for payment of interest on any Debt Security; (v) waive a Default or an
Event of Default in the payment of principal of, or premium, if any, or interest
on a Debt Security except for a rescission of an acceleration of such Debt
Securities by the Holders of at least a majority in aggregate principal amount
of such Debt Securities and a waiver of the payment default that resulted from
such acceleration; (vi) except as otherwise permitted under the Indenture,
release any security that may have been granted in respect of the Debt
Securities; (vii) make any Debt Security payable in Currency other than that
stated in the Debt Security; (viii) make any change in the provisions of the
Indenture relating to waivers of past Defaults or the rights of Holders to
receive payments of principal of or premium, if any, or interest on the Debt
Securities; (ix) waive a redemption payment with respect to any Debt Security
(other than a payment required by a covenant requiring the repurchase of the
Debt Securities of such series if so permitted by the Board Resolutions or
supplemental Indenture establishing the terms of such series); (x) except as
otherwise permitted under the Indenture with respect to Debt Securities that are
guaranteed, release any guarantor from its obligations under the Indenture or
under its guarantee or change any guarantee in any manner that would adversely
affect the rights of Holders of such Debt Securities; or (xi) make any change in
Section 6.06 or this Section 9.02.

                  A supplemental Indenture which changes or eliminates any
covenant or other provision of the Indenture which has been expressly included
solely for the benefit of one or more particular series of Debt Securities or
which modifies the rights of the Holders of Debt Securities of such series with
respect to such covenant or other provision, shall be deemed not to affect the
rights under the Indenture of the Holders of Debt Securities of any other
series.

                  Upon the request of the Issuers, accompanied by copies of
Board Resolutions authorizing the execution of any such supplemental Indenture,
and upon the filing with the Trustee of evidence of the consent of Holders as
aforesaid, the Trustee shall join with the Issuers and any guarantors with
respect to any Debt Securities in the execution of such supplemental Indenture
unless such supplemental Indenture affects the Trustee's own rights, duties or
immunities under the Indenture or otherwise, in which case the Trustee may in
its discretion but shall not be obligated to enter into such supplemental
Indenture.

                                       48
<PAGE>

                  It shall not be necessary for the consent of the Holders under
this Section 9.02 to approve the particular form of any proposed supplemental
Indenture, but it shall be sufficient if such consent shall approve the
substance thereof.

                  After an amendment or waiver under this Section 9.02 becomes
effective, the Issuers shall mail to Holders of Debt Securities of each series
affected thereby a notice briefly describing such amendment or waiver. The
failure to give such notice to all such Holders, or any defect therein, shall
not impair or affect the validity of an amendment or waiver under this Section
9.02.

                  SECTION 9.03. Effect of Supplemental Indentures. Upon the
                                ---------------------------------
execution of any supplemental Indenture pursuant to the provisions of this
Article IX, the Indenture shall be and be deemed to be modified and amended in
accordance therewith and the respective rights, limitations of rights,
obligations, duties and immunities under the Indenture of the Trustee, the
Issuers and the Holders shall thereafter be determined, exercised and enforced
hereunder subject in all respects to such modifications and amendments, and all
the terms and conditions of any such supplemental Indenture shall be and be
deemed to be part of the terms and conditions of the Indenture for any and all
purposes.

                  The Trustee, subject to the provisions of Sections 7.01 and
7.02, may receive an Officers' Certificate and an Opinion of Counsel as
conclusive evidence that any such supplemental Indenture complies with the
provisions of this Article IX.

                  SECTION 9.04. Debt Securities May Bear Notation of Changes by
                                -----------------------------------------------
Supplemental Indentures. Debt Securities of any series authenticated and
-----------------------
delivered after the execution of any supplemental Indenture pursuant to the
provisions of this Article IX may, and shall if required by the Trustee, bear a
notation in form approved by the Trustee as to any matter provided for in such
supplemental Indenture. New Debt Securities of any series so modified as to
conform, in the opinion of the Trustee and the Board of Directors, to any
modification of the Indenture contained in any such supplemental Indenture may
be prepared and executed by the Issuers, authenticated by the Trustee and
delivered in exchange for the Debt Securities of such series then outstanding.
Failure to make the appropriate notation or to issue a new Debt Security of such
series shall not affect the validity of such amendment.

                                   ARTICLE X

                   Consolidation, Merger, Sale or Conveyance
                   -----------------------------------------

                  SECTION 10.01. Consolidations and Mergers of the Issuers.
                                 -----------------------------------------
Neither of the Issuers may, directly or indirectly: (1) consolidate or merge
with or into another Person (whether or not such Issuer is the survivor); or (2)
sell, assign, transfer, lease, convey or otherwise dispose of all or
substantially all of its properties or assets, in one or more related
transactions, to another Person; unless:

                  (1) either (a) such Issuer is the surviving entity of such
transaction; or (b) the Person formed by or surviving any such consolidation or
merger (if other than such Issuer) or to which such sale, assignment, transfer,
lease, conveyance or other disposition shall have been

                                       49
<PAGE>

made (the "Successor Company") is an entity organized or existing under the laws
of the United States, any state thereof or the District of Columbia, provided
that PAA Finance may not consolidate or merge with or into any entity other than
a corporation satisfying such requirement for so long as the Partnership is not
a corporation;

                  (2)  the Successor Company assumes all the obligations of such
Issuer under the notes and the Indenture pursuant to agreements reasonably
satisfactory to the Trustee;

                  (3)  immediately after such transaction no Default or Event of
Default exists; and

                  (4)  such Issuer has delivered to the Trustee an Officers'
Certificate and an Opinion of Counsel, each stating that such consolidation,
merger or transfer and, if a supplemental Indenture is required, such
supplemental Indenture complies with the Indenture and all conditions precedent
therein relating to such transaction have been satisfied.

                  SECTION 10.02. Rights and Duties of Successor Company. In case
                                 --------------------------------------
of any consolidation, merger or disposition respecting an Issuer in accordance
with Section 10.01, the Successor Company shall succeed to and be substituted
for such Issuer, with the same effect as if it had been named herein as the
party of the first part, and the Issuer shall be relieved of any further
obligation under the Indenture and the Debt Securities. The Successor Company
thereupon may cause to be signed, and may issue either in its own name or in the
name of such Issuer, any or all the Debt Securities issuable hereunder which
theretofore shall not have been signed by such Issuer and delivered to the
Trustee; and, upon the order of the Successor Company, instead of such Issuer,
and subject to all the terms, conditions and limitations in the Indenture
prescribed, the Trustee shall authenticate and shall deliver any Debt Securities
which previously shall have been signed and delivered by the officers of such
Issuer or its Managing General Partner, as the case may be, to the Trustee for
authentication, and any Debt Securities which the Successor Company thereafter
shall cause to be signed and delivered to the Trustee for that purpose. All the
Debt Securities so issued shall in all respects have the same legal rank and
benefit under the Indenture as the Debt Securities theretofore or thereafter
issued in accordance with the terms of the Indenture as though all such Debt
Securities had been issued at the date of the execution hereof.

                  In case of any such consolidation, merger or disposition such
changes in phraseology and form (but not in substance) may be made in the Debt
Securities appertaining thereto thereafter to be issued as may be appropriate.

                                  ARTICLE XI

                   Satisfaction and Discharge of Indenture;
                   ---------------------------------------
                               Unclaimed Moneys
                               ----------------

                  SECTION 11.01. Satisfaction and Discharge; Application of
                                 ------------------------------------------
Trust Money. The Indenture shall upon the request of the Issuers cease to be of
-----------
further effect with respect to all Outstanding Debt Securities of any series
(except as to surviving rights of registration of transfer or exchange of Debt
Securities of such series herein expressly provided for, the Issuers'

                                       50
<PAGE>

obligations under Section 7.06, and the Trustee's and each paying agent's
obligations under the last paragraph of this Section 11.01 and Section 11.02)
and the Trustee, on demand and at the expense of the Issuers, shall execute
proper instruments acknowledging satisfaction and discharge of the Indenture
with respect to such series, when:

                  (a)  either

                       (i)   all outstanding Debt Securities of such series
         therefore authenticated and delivered (other than (A) Debt Securities
         which have been destroyed, lost or stolen and which have been replaced
         or paid as provided in Section 2.09 and (B) Debt Securities for whose
         payment money has been deposited in trust with the Trustee or any
         paying agent and thereafter repaid to either Issuer or discharged from
         such trust) have been delivered to the Trustee for cancellation; or

                       (ii)  all outstanding Debt Securities of such series not
         theretofore delivered to the Trustee for cancellation

                             (A)  have become due and payable by reason of the
         giving of a notice of redemption or otherwise,

                             (B)  shall become due and payable at their Stated
         Maturity within one year, or

                             (C)  are to be called for redemption within one
                  year under arrangements satisfactory to the Trustee for the
                  giving of notice of redemption by the Trustee in the name, and
                  at the expense, of the Issuers,

                  and the Issuers, in the case of clause (A), (B) or (C) above,
                  have irrevocably deposited or caused to be irrevocably
                  deposited with the Trustee as trust funds in trust for such
                  purpose cash in Dollars or U.S. Government Obligations, or a
                  combination thereof, in an amount sufficient (without
                  consideration of any reinvestment of interest and as certified
                  by an independent public accountant designated by the
                  Partnership expressed in a written certification thereof
                  delivered to the Trustee) to pay and discharge the entire
                  indebtedness of such Debt Securities not theretofore delivered
                  to the Trustee for cancellation, for principal (and premium,
                  if any) and accrued and unpaid interest to the date of such
                  deposit (in the case of Debt Securities which have become due
                  and payable) or the Stated Maturity or redemption date, as the
                  case may be;

                  (b)  the Issuers have paid or caused to be paid all other sums
         then due and payable hereunder by them under the Indenture; and

                  (c)  the Partnership has delivered to the Trustee an Officers'
         Certificate and an Opinion of Counsel, each stating that all conditions
         precedent herein provided for relating to the satisfaction and
         discharge of the Indenture have been complied with.

In order to have money available on a payment date to pay principal (and
premium, if any, on) and interest on the Notes, the U.S. Government Obligations
shall be payable as to principal (and

                                       51
<PAGE>

premium, if any) or interest at least one Business Day before such payment date
in such amounts as shall provide the necessary money.

                  The Trustee shall hold in trust money or U.S. Government
Obligations deposited with it pursuant to this Article XI. It shall apply the
deposited money and the money from U.S. Government Obligations through any
paying agent and in accordance with the Indenture to the payment of principal
of, and premium, if any, and interest on, the Debt Securities of the defeased
series. Prior to the maturity of such series, the Trustee may, at the written
direction of the Issuers, invest such money in U.S. Government Obligations.

                  SECTION 11.02. Repayment to Issuers. The Trustee and any
                                 --------------------
paying agent shall promptly turn over to the Issuers upon request any excess
money or securities held by them at any time.

                  Subject to any applicable abandoned property law, the Trustee
and any paying agent shall pay to the Issuers upon request any money held by
them for the payment of principal, premium or interest that remains unclaimed
for two years, and, thereafter, Holders entitled to such money must look to the
Issuers for payment as general creditors.

                  SECTION 11.03. Indemnity for U.S. Government Obligations. The
                                 -----------------------------------------
Issuers shall pay and shall indemnify the Trustee and the Holders against any
tax, fee or other charge imposed on or assessed against deposited U.S.
Government Obligations or the principal and interest received on such U.S.
Government Obligations.

                  SECTION 11.04. Reinstatement. If the Trustee or any paying
                                 -------------
agent is unable to apply any money or U.S. Government Obligations in accordance
with this Article XI by reason of any legal proceeding or by reason of any order
or judgment of any court or government authority enjoining, restraining or
otherwise prohibiting such application, the Issuers' obligations under the
Indenture and the Debt Securities of the defeased series shall be revived and
reinstated as though no deposit had occurred pursuant to this Article XI until
such time as the Trustee or any paying agent is permitted to apply all such
money or U.S. Government Obligations in accordance with this Article XI.

                                  ARTICLE XII

                           Miscellaneous Provisions
                           ------------------------

                  SECTION 12.01. Successors and Assigns of Issuers Bound by
                                 ------------------------------------------
Indenture. All the covenants, stipulations, promises and agreements in the
---------
Indenture contained by or in behalf of the Issuers or the Trustee shall bind
their respective successors and assigns, whether so expressed or not.

                  SECTION 12.02. Acts of Board, Committee or Officer of
                                 --------------------------------------
Successor Company Valid. Any act or proceeding by any provision of the Indenture
-----------------------
authorized or required to be done or performed by any Board of Directors,
committee thereof or officer of the Managing General Partner or PAA Finance, as
applicable, shall and may be done and performed with like force and effect by
the like Board of Directors, committee thereof or officer of any Successor
Company.

                                       52
<PAGE>

                  SECTION 12.03. Required Notices or Demands. Except as
                                 ---------------------------
otherwise expressly provided in the Indenture, any notice or demand which by any
provision of the Indenture is required or permitted to be given or served by the
Trustee or by the Holders to or on the Issuers shall be in writing in the
English language and may be given or served by being deposited postage prepaid
in a post office letter box in the United States addressed (until another
address is filed by the Issuers with the Trustee) as follows: Plains All
American Pipeline, L.P., 333 Clay Street, Suite 2900, Houston, Texas 77002,
Attention: General Counsel. Except as otherwise expressly provided in the
Indenture, any notice, direction, request or demand by the Issuers or by any
Holder to or upon the Trustee shall be in writing in the English language and
may be given or made, for all purposes, by being deposited, postage prepaid, in
a post office letter box in the United States addressed to the Corporate Trust
Office of the Trustee initially at 5847 San Felipe, Suite 1050, Houston, Texas
77057, Attention: Corporate Trust Group. The Issuers or the Trustee by notice to
the other may designate additional or different addresses for subsequent notices
or communications.

                  Any notice required or permitted to a Registered Holder by the
Issuers or the Trustee pursuant to the provisions of the Indenture shall be in
writing in the English language and shall be deemed to be properly mailed by
being deposited postage prepaid in a post office letter box in the United States
addressed to such Holder at the address of such Holder as shown on the Debt
Security Register. Any report pursuant to Section 313 of the Trust Indenture Act
shall be transmitted in compliance with subsection (c) therein.

                  In the event of suspension of regular mail service or by
reason of any other cause it shall be impracticable to give notice by mail, then
such notification as shall be given with the approval of the Trustee shall
constitute sufficient notice for every purpose thereunder.

                  Failure to mail a notice or communication to a Holder or any
defect in it or any defect in any notice by publication as to a Holder shall not
affect the sufficiency of such notice with respect to other Holders. If a notice
or communication is mailed or published in the manner provided above, it is
conclusively presumed duly given.

                  SECTION 12.04. Indenture and Debt Securities to Be Construed
                                 ---------------------------------------------
in Accordance with the Laws of the State of New York. The Indenture and each
----------------------------------------------------
Debt Security shall be deemed to be New York contracts, and for all purposes
shall be construed in accordance with the laws of said State.

                  SECTION 12.05. Officers' Certificate and Opinion of Counsel to
                                 -----------------------------------------------
Be Furnished upon Application or Demand by the Issuers. Upon any application or
------------------------------------------------------
demand by the Issuers to the Trustee to take any action under any of the
provisions of the Indenture, the Issuers shall furnish to the Trustee an
Officers' Certificate stating that all conditions precedent provided for in the
Indenture relating to the proposed action have been complied with and an Opinion
of Counsel stating that, in the opinion of such counsel, all such conditions
precedent have been complied with, except that in the case of any such
application or demand as to which the furnishing of such document is
specifically required by any provision of the Indenture relating to such
particular application or demand, no additional certificate or opinion need be
furnished.

                                       53
<PAGE>

                  Each certificate or opinion provided for in the Indenture and
delivered to the Trustee with respect to compliance with a condition or covenant
provided for in the Indenture shall include (1) a statement that the Person
making such certificate or opinion has read such covenant or condition, (2) a
brief statement as to the nature and scope of the examination or investigation
upon which the statements or opinions contained in such certificate or opinion
are based, (3) a statement that, in the opinion of such Person, he has made such
examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with and (4) a statement as to whether or not, in the opinion of such
Person, such condition or covenant has been complied with.

                  SECTION 12.06. Payments Due on Legal Holidays. In any case
                                 ------------------------------
where the date of maturity of interest on or principal of and premium, if any,
on the Debt Securities of a series or the date fixed for redemption or repayment
of any Debt Security or the making of any sinking fund payment shall not be a
business day at any Place of Payment for the Debt Securities of such series,
then payment of interest or principal and premium, if any, or the making of such
sinking fund payment need not be made on such date at such Place of Payment, but
may be made on the next succeeding business day at such Place of Payment with
the same force and effect as if made on the date of maturity or the date fixed
for redemption, and no interest shall accrue for the period after such date. If
a record date is not a business day, the record date shall not be affected.

                  SECTION 12.07. Provisions Required by Trust Indenture Act to
                                 ---------------------------------------------
Control. If and to the extent that any provision of the Indenture limits,
-------
qualifies or conflicts with another provision included in the Indenture which is
required to be included in the Indenture by any of Sections 310 to 318,
inclusive, of the Trust Indenture Act, such required provision shall control.

                  SECTION 12.08. Computation of Interest on Debt Securities.
                                 ------------------------------------------
Interest, if any, on the Debt Securities shall be computed on the basis of a
 360-day year of twelve 30-day months, except as may otherwise be provided
pursuant to Section 2.03.

                  SECTION 12.09. Rules by Trustee, Paying Agent and Registrar.
                                 --------------------------------------------
The Trustee may make reasonable rules for action by or a meeting of Holders. The
Registrar and any paying agent may make reasonable rules for their functions.

                  SECTION 12.10. No Recourse Against Others. No past, present or
                                 --------------------------
future director, officer, partner, employee, incorporator, manager, stockholder,
unitholder or member of the Issuers, the General Partner, the Managing General
Partner or any other obligor on the Debt Securities of any series, as such,
shall have any liability for any obligations of the Issuers or such other
obligors under the Debt Securities, the Indenture or for any claim based on, in
respect of, or by reason of, such obligations or their creation. Each Holder by
accepting a Debt Security waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Debt Securities.

                  SECTION 12.11. Severability. In case any provision in the
                                 ------------
Indenture or the Debt Securities shall be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions shall not in
any way be affected or impaired thereby.

                                       54
<PAGE>

                  SECTION 12.12. Effect of Headings. The article and section
                                 ------------------
headings herein and in the Table of Contents are for convenience only and shall
not affect the construction hereof.

                  SECTION 12.13. Indenture May Be Executed in Counterparts. The
                                 -----------------------------------------
Indenture may be executed in any number of counterparts, each of which shall be
an original, but such counterparts shall together constitute but one and the
same instrument.

                  The Trustee hereby accepts the trusts in the Indenture upon
the terms and conditions herein set forth.

                                       55
<PAGE>

                  IN WITNESS WHEREOF, the parties hereto have caused the
Indenture to be duly signed as of the date first written above.

                                       PLAINS ALL AMERICAN PIPELINE, L.P.

                                         By PLAINS PAA, L.P.,
                                         its General Partner

                                         By PLAINS ALL AMERICAN GP LLC,
                                         its General Partner

                                            By__________________________________
                                              Name:
                                              Title:

                                       PAA FINANCE CORP

                                            By__________________________________
                                              Name:
                                              Title:

                                       FIRST UNION NATIONAL BANK

                                            By__________________________________
                                              Name:
                                              Title:

                                       56<PAGE>

                                                                     EXHIBIT 4.2

                      PLAINS ALL AMERICAN PIPELINE, L.P.,

                               PAA FINANCE CORP.

                                      and

                           FIRST UNION NATIONAL BANK

                                  as Trustee

                                _______________

                            SUBORDINATED INDENTURE

                              Dated as of _______

                                DEBT SECURITIES

                                  (UNLIMITED)
<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<S>                                                                                                           <C>
ARTICLE I Definitions........................................................................................  1

   SECTION 1.01.    Certain Terms Defined....................................................................  1
   SECTION 1.02.    Other Definitions........................................................................  8
   SECTION 1.03.    Incorporation by Reference of Trust Indenture Act........................................  8
   SECTION 1.04.    Rules of Construction....................................................................  9

ARTICLE II Debt Securities...................................................................................  9

   SECTION 2.01.    Forms Generally..........................................................................  9
   SECTION 2.02.    Form of Trustee's Certificate of Authentication..........................................  9
   SECTION 2.03.    Principal Amount; Issuable in Series..................................................... 10
   SECTION 2.04.    Execution of Debt Securities............................................................. 12
   SECTION 2.05.    Authentication and Delivery of Debt Securities........................................... 13
   SECTION 2.06.    Denomination of Debt Securities.......................................................... 14
   SECTION 2.07.    General Provisions for Registration of Transfer and Exchange............................. 14
   SECTION 2.08.    Temporary Debt Securities................................................................ 15
   SECTION 2.09.    Mutilated, Destroyed, Lost or Stolen Debt Securities..................................... 16
   SECTION 2.10.    Cancellation of Surrendered Debt Securities.............................................. 17
   SECTION 2.11.    Provisions of the Indenture and Debt Securities for the Sole Benefit of the Parties and
                    the Holders.............................................................................. 17
   SECTION 2.12.    Payment of Interest; Rights Preserved.................................................... 17
   SECTION 2.13.    Securities Denominated in Foreign Currencies............................................. 18
   SECTION 2.14.    Wire Transfers........................................................................... 18
   SECTION 2.15.    Securities Issuable in the Form of a Global Security..................................... 18
   SECTION 2.16.    Medium Term Securities................................................................... 20
   SECTION 2.17.    Defaulted Interest....................................................................... 21
   SECTION 2.18.    Judgments................................................................................ 22
   SECTION 2.19.    CUSIP Numbers............................................................................ 22

ARTICLE III Redemption of Debt Securities.................................................................... 22

   SECTION 3.01.    Applicability of Article................................................................. 22
   SECTION 3.02.    Notice of Redemption; Selection of Debt Securities....................................... 23
   SECTION 3.03.    Payment of Debt Securities Called for Redemption......................................... 24
   SECTION 3.04.    Mandatory and Optional Sinking Funds..................................................... 25
   SECTION 3.05.    Redemption of Debt Securities for Sinking Fund........................................... 25

ARTICLE IV Particular Covenants of the Issuers............................................................... 27

   SECTION 4.01.    Payment of Principal of, and Premium, If Any, and Interest on, Debt Securities........... 27
   SECTION 4.02.    Maintenance of Offices or Agencies for Registration of Transfer, Exchange and Payment of
                    Debt Securities.......................................................................... 27
   SECTION 4.03.    Appointment to Fill a Vacancy in the Office of Trustee................................... 28
   SECTION 4.04.    Duties of Paying Agents, etc............................................................. 28
   SECTION 4.05.    Statement by Officers as to Default...................................................... 29
   SECTION 4.06.    Further Instruments and Acts............................................................. 29
   SECTION 4.07.    Corporate, Partnership or Limited Liability Company Existence............................ 29
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>                                                                                                           <C>
   SECTION 4.08.    Maintenance of Properties................................................................ 29
   SECTION 4.09.    Payment of Taxes and Other Claims........................................................ 30
   SECTION 4.10.    Calculation of Original Issue Discount................................................... 30
   SECTION 4.11.    Stay, Extension and Usury Laws........................................................... 30

ARTICLE V Holders' Lists and Reports by the Issuers and the Trustee.......................................... 30

   SECTION 5.01.    Issuers to Furnish Trustee Information as to Names and Addresses of Holders; Preservation
                    of Information........................................................................... 30
   SECTION 5.02.    Communications to Holders; Meetings of Holders........................................... 31
   SECTION 5.03.    Reports by Issuers....................................................................... 32
   SECTION 5.04.    Reports by Trustee....................................................................... 32
   SECTION 5.05.    Record Dates for Action by Holders....................................................... 33

ARTICLE VI Remedies of the Trustee and Holders in Event of Default........................................... 33

   SECTION 6.01.    Events of Default........................................................................ 33
   SECTION 6.02.    Collection of Indebtedness by Trustee, etc............................................... 34
   SECTION 6.03.    Application of Moneys Collected by Trustee............................................... 35
   SECTION 6.04.    Limitation on Suits by Holders........................................................... 36
   SECTION 6.05.    Remedies Cumulative; Delay or Omission in Exercise of Rights Not a Waiver of Default..... 37
   SECTION 6.06.    Rights of Holders of Majority in Principal Amount of Debt Securities to Direct Trustee
                    and to Waive Default..................................................................... 37
   SECTION 6.07.    Trustee to Give Notice of Defaults Known to It, but May Withhold Such Notice in Certain
                    Circumstances............................................................................ 38
   SECTION 6.08.    Requirement of an Undertaking To Pay Costs in Certain Suits under the Indenture or
                    Against the Trustee...................................................................... 38

ARTICLE VII Concerning the Trustee........................................................................... 39

   SECTION 7.01.    Certain Duties and Responsibilities...................................................... 39
   SECTION 7.02.    Certain Rights of Trustee................................................................ 40
   SECTION 7.03.    Trustee Not Liable for Recitals in Indenture or in Debt Securities....................... 41
   SECTION 7.04.    Trustee, Paying Agent or Registrar May Own Debt Securities............................... 42
   SECTION 7.05.    Moneys Received by Trustee to Be Held in Trust........................................... 42
   SECTION 7.06.    Compensation and Reimbursement........................................................... 42
   SECTION 7.07.    Right of Trustee to Rely on an Officers' Certificate Where No Other Evidence Specifically
                    Prescribed............................................................................... 42
   SECTION 7.08.    Separate Trustee; Replacement of Trustee................................................. 43
   SECTION 7.09.    Successor Trustee by Merger.............................................................. 44
   SECTION 7.10.    Eligibility; Disqualification............................................................ 44
   SECTION 7.11.    Preferential Collection of Claims Against Issuers........................................ 45
   SECTION 7.12.    Compliance with Tax Laws................................................................. 45

ARTICLE VIII Concerning the Holders.......................................................................... 45

   SECTION 8.01.    Evidence of Action by Holders............................................................ 45
   SECTION 8.02.    Proof of Execution of Instruments and of Holding of Debt Securities...................... 45
   SECTION 8.03.    Who May Be Deemed Owner of Debt Securities............................................... 45
   SECTION 8.04.    Instruments Executed by Holders Bind Future Holders...................................... 46
</TABLE>

                                      ii
<PAGE>

<TABLE>
<S>                                                                                                           <C>
ARTICLE IX Amendment, Supplement and Waiver.................................................................. 46

   SECTION 9.01.    Without Consent of Holders of Debt Securities............................................ 46
   SECTION 9.02.    With Consent of Holders of Debt Securities............................................... 48
   SECTION 9.03.    Effect of Supplemental Indentures........................................................ 49
   SECTION 9.04.    Debt Securities May Bear Notation of Changes by Supplemental Indentures.................. 49

ARTICLE X Consolidation, Merger, Sale or Conveyance.......................................................... 50

   SECTION 10.01.   Consolidations and Mergers of the Issuers................................................ 50
   SECTION 10.02.   Rights and Duties of Successor Company................................................... 50

ARTICLE XI Satisfaction and Discharge of Indenture; Unclaimed Moneys......................................... 51

   SECTION 11.01.   Satisfaction and Discharge; Application of Trust Money................................... 51
   SECTION 11.02.   Repayment to Issuers..................................................................... 52
   SECTION 11.03.   Indemnity for U.S. Government Obligations................................................ 52
   SECTION 11.04.   Reinstatement............................................................................ 52

ARTICLE XII Miscellaneous Provisions......................................................................... 53

   SECTION 12.01.   Successors and Assigns of Issuers Bound by Indenture..................................... 53
   SECTION 12.02.   Acts of Board, Committee or Officer of Successor Company Valid........................... 53
   SECTION 12.03.   Required Notices or Demands.............................................................. 53
   SECTION 12.04.   Indenture and Debt Securities to Be Construed in Accordance with the Laws of the State of
                    New York................................................................................. 54
   SECTION 12.05.   Officers' Certificate and Opinion of Counsel to Be Furnished upon Application or Demand
                    by the Issuers........................................................................... 54
   SECTION 12.06.   Payments Due on Legal Holidays........................................................... 54
   SECTION 12.07.   Provisions Required by Trust Indenture Act to Control.................................... 54
   SECTION 12.08.   Computation of Interest on Debt Securities............................................... 55
   SECTION 12.09.   Rules by Trustee, Paying Agent and Registrar............................................. 55
   SECTION 12.10.   No Recourse Against Others............................................................... 55
   SECTION 12.11.   Severability............................................................................. 55
   SECTION 12.12.   Effect of Headings....................................................................... 55
   SECTION 12.13.   Indenture May Be Executed in Counterparts................................................ 55

ARTICLE XIII Subordination of Debt Securities................................................................ 55

   SECTION 13.01.   Applicability of Article; Agreement to Subordinate....................................... 55
   SECTION 13.02.   Liquidation, Dissolution, Bankruptcy..................................................... 55
   SECTION 13.03.   Default on Senior Indebtedness........................................................... 56
   SECTION 13.04.   Acceleration of Payment of Debt Securities............................................... 57
   SECTION 13.05.   When Distribution Must Be Paid Over...................................................... 57
   SECTION 13.06.   Subrogation.............................................................................. 57
   SECTION 13.07.   Relative Rights.......................................................................... 57
   SECTION 13.08.   Subordination May Not Be Impaired by Issuers............................................. 57
   SECTION 13.09.   Rights of Trustee and Paying Agent....................................................... 58
   SECTION 13.10.   Distribution or Notice to Representative................................................. 58
   SECTION 13.11.   Article XIII Not to Prevent Defaults or Limit Right to Accelerate........................ 58
   SECTION 13.12.   Trust Moneys Not Subordinated............................................................ 58
</TABLE>

                                      iii
<PAGE>

<TABLE>
<S>                                                                                                           <C>
   SECTION 13.13.   Trustee Entitled to Rely................................................................. 58
   SECTION 13.14.   Trustee to Effectuate Subordination...................................................... 59
   SECTION 13.15.   Trustee Not Fiduciary for Holders of Senior Indebtedness................................. 59
   SECTION 13.16.   Reliance by Holders of Senior Indebtedness on Subordination Provisions................... 59
</TABLE>

                                      iv
<PAGE>

                              CROSS-REFERENCE TABLE

<TABLE>
<CAPTION>
     Trust Indenture
       Act Section                                                                                  Indenture Section
       -----------                                                                                  -----------------
<S>                                                                                                 <C>
310(a)(1)...........................................................................................             7.10
(a)(2)..............................................................................................             7.10
(a)(3)..............................................................................................              N/A
(a)(4)..............................................................................................              N/A
(a)(5)..............................................................................................             7.10
(b).................................................................................................             7.10
(c).................................................................................................              N/A
311(a)..............................................................................................             7.11
(b).................................................................................................             7.11
(c).................................................................................................              N/A
312(a)..............................................................................................             5.01
(b).................................................................................................             5.02
(c).................................................................................................             5.02
313(a)..............................................................................................             5.04
(b)(1)..............................................................................................             5.04
(b)(2)..............................................................................................             5.04
(c).................................................................................................      5.04; 12.03
(d).................................................................................................             5.04
314(a)..............................................................................................      5.03; 12.03
(b).................................................................................................              N/A
(c)(1)..............................................................................................            12.05
(c)(2)..............................................................................................            12.05
(c)(3)..............................................................................................              N/A
(d).................................................................................................              N/A
(e).................................................................................................            12.05
(f).................................................................................................              N/A
315(a)..............................................................................................             7.01
(b).................................................................................................      6.07; 12.03
(c) ................................................................................................             7.01
(d).................................................................................................             7.01
(e).................................................................................................             6.03
316(a)(last sentence)...............................................................................             1.01
(a)(1)(A)...........................................................................................             6.06
(a)(1)(B)...........................................................................................             6.06
(a)(2)..............................................................................................              N/A
(b).................................................................................................             6.04
(c).................................................................................................             2.17
317(a)(1)...........................................................................................             6.02
(a)(2)..............................................................................................             6.09
(b).................................................................................................              404
318(a)..............................................................................................            12.07
(b).................................................................................................              N/A
</TABLE>

                                       v
<PAGE>

<TABLE>
<S>                                                                                                             <C>
(c).................................................................................................            12.07
</TABLE>

_________________

N/A means not applicable.

                                     vi
<PAGE>

                  THIS SUBORDINATED INDENTURE dated as of ______, is among
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 FIRST UNION NATIONAL BANK, a
national banking association (the "Trustee").

                                  WITNESSETH:

                  WHEREAS, Plains All American GP LLC, a Delaware limited
liability company (the "Managing General Partner"), as general partner of Plains
AAP, L.P., a Delaware limited partnership (the "General Partner") and the
general partner of the Partnership, and PAA Finance have duly authorized the
execution and delivery of the Indenture to provide for the issuance from time to
time of their subordinated debentures, notes, bonds or other evidences of
indebtedness to be issued in one or more series in an unlimited aggregate
principal amount (herein called the "Debt Securities"), as in the Indenture
provided.

                  WHEREAS, all things necessary to make the Indenture a valid
agreement of the Issuers, in accordance with its terms, have been done.

                  NOW, THEREFORE, in consideration of the agreements and
obligations set forth herein and for good and valuable consideration, the
sufficiency of which is hereby acknowledged, the Issuers and the Trustee hereby
agree with each other, for the equal and proportionate benefit of the respective
Holders from time to time of the Debt Securities or any series thereof, as
follows:

                                   ARTICLE I

                                  Definitions
                                  -----------

                  SECTION 1.01.     Certain Terms Defined. The terms defined in
                                    ---------------------
this Section 1.01 (except as herein otherwise expressly provided or unless the
context otherwise requires) for all purposes of the Indenture and of any
Indenture supplemental hereto shall have the respective meanings specified in
this Section 1.01. All other terms used in the Indenture which are defined in
the Trust Indenture Act or which are by reference therein defined in the
Securities Act (except as herein otherwise expressly provided or unless the
context otherwise requires), shall have the meanings assigned to such terms in
the Trust Indenture Act and in the Securities Act as in force as of the date of
original execution of the Indenture.

                  "Bankruptcy Law" means Title 11, U.S. Code or any similar
                   --------------
federal or state law for the relief of debtors.

                  "Blockage Notice" has the meaning set forth in Section 13.03.
                   ---------------

                  "Board of Directors" means (a) with respect to the
                   ------------------
Partnership, the board of directors of the Managing General Partner, and (b)
with respect to PAA Finance, its board of directors, or, in each case, with
respect to any determination or resolution required or permitted to be made
hereunder, any duly authorized committee or subcommittee of such board. All
references in the Indenture to "Board of Directors" shall be deemed to refer to
the Board of

                                       1
<PAGE>

Directors of the Partnership, unless otherwise expressly indicated or the
context otherwise requires.

                   "Board Resolution" means a copy of a resolution certified by
                    ----------------
the appropriate person to have been duly adopted by the Board of Directors and
to be in full force and effect on the date of such certification.

                  "Business Day" means each Monday, Tuesday, Wednesday, Thursday
                   ------------
and Friday which is not a day on which banking institutions in Houston, Texas,
the Borough of Manhattan, the City of New York, New York, or the city in which
the Corporate Trust Office of the Trustee is located, are authorized or
obligated by law or executive order to close.

                  "Code" means the Internal Revenue Code of 1986, as amended
                   ----
from time to time and any successor statute.

                  "Commission" means the Securities and Exchange Commission, as
                   ----------
from time to time constituted, created under the Exchange Act, or, if at any
time after the execution of the Indenture such Commission is not existing and
performing the duties now assigned to it under the Trust Indenture Act, then the
body performing such duties at such time.

                  "Corporate Trust Office of the Trustee" means the principal
                   -------------------------------------
corporate trust office of the Trustee, at which at any particular time its
corporate trust business shall be administered, which office at the date of
execution of the Indenture is located at 1525 West W.T. Harris Blvd.-3C3,
Charlotte, North Carolina 28288-1153, Attention: Corporate Trust Operations.

                  "Currency" means Dollars or Foreign Currency.
                   --------

                  "Debt Security" or "Debt Securities" has the meaning stated in
                   -------------      ---------------
the first recital of the Indenture and more particularly means any debt security
or debt securities, as the case may be, of any series authenticated and
delivered under the Indenture.

                  "Default" means any event that is, or with the passage of time
                   -------
or the giving of notice or both would be, an Event of Default.

                  "Depositary" means, unless otherwise specified by the Issuers
                   ----------
pursuant to either Section 2.03 or 2.15, with respect to registered Debt
Securities of any series issuable or issued in whole or in part in the form of
one or more Global Securities, The Depository Trust Company, New York, New York,
or any successor thereto registered as a clearing agency under the Exchange Act
or other applicable statute or regulations.

                  "Designated Senior Indebtedness" means, as to any series of
                   ------------------------------
Debt Securities, any Senior Indebtedness identified as Designated Senior
Indebtedness in the Board Resolution or supplemental Indenture setting forth the
terms of such series.

                  "Dollar" or "$" means such currency of the United States as at
                   ------
the time of payment is legal tender for the payment of public and private debts.

                                       2
<PAGE>

                  "Dollar Equivalent" means, with respect to any monetary amount
                   -----------------
in a Foreign Currency, at any time for the determination thereof, the amount of
Dollars obtained by converting such Foreign Currency involved in such
computation into Dollars at the spot rate for the purchase of Dollars with the
applicable Foreign Currency as quoted by Citibank, N.A. (unless another
comparable financial institution is designated by the Issuers) in New York, New
York at approximately 11:00 a.m. (New York time) on the date two business days
prior to such determination.

                  "Equity Interests" means:
                   ----------------

                  (1)      in the case of a corporation, corporate stock;

                  (2)      in the case of an association or a business entity,
any and all shares, interests, participations, rights or other equivalents
(however designated) of corporate stock;

                  (3)      in the case of a partnership or limited liability
company, partnership or membership interests (whether general or limited);

                  (4)      any other interest or participation that confers on a
Person the right to receive a share of the profits and losses of, or
distributions of assets of, the issuing Person; and

                  (5)      all warrants, options or other rights to acquire any
of the interests described in clauses (1) through (4) above (but excluding any
debt security that is convertible into, or exchangeable for, any of the
interests described in clauses (1) through (4) above).

                  "Event of Default" has the meaning specified in Section 6.01.
                   ----------------

                  "Exchange Act" means the Securities Exchange Act of 1934, as
                   ------------
amended, or any successor statute.

                  "Floating Rate Security" means a Debt Security that provides
                   ----------------------
for the payment of interest at a variable rate determined periodically by
reference to an interest rate index specified pursuant to Section 2.03.

                  "Foreign Currency" means a currency issued or adopted by the
                   ----------------
government of any country other than the United States or a composite currency
the value of which is determined by reference to the values of the currencies of
any group of countries.

                  "GAAP" means United States generally accepted accounting
                   ----
principles set forth in the opinions and pronouncements of the Accounting
Principles Board of the American Institute of Certified Public Accountants and
statements and pronouncements of the Financial Accounting Standards Board or in
such other statements by such other entity as have been approved by a
significant segment of the accounting profession, which are in effect from time
to time.

                  "General Partner" means Plains AAP, L.P., a Delaware limited
                   ---------------
liability company, and its successors and permitted assigns as general partner
of the Partnership.

                                       3
<PAGE>

                  "Global Security" means with respect to any series of Debt
                   ---------------
Securities issued hereunder, a Debt Security that is executed by the Issuers and
authenticated and delivered by the Trustee to the Depositary or pursuant to the
Depositary's instruction, all in accordance with the Indenture, or the
applicable Board Resolution and set forth in an Officers' Certificate, which
shall be registered in the name of the Depositary or its nominee and which shall
represent, and shall be denominated in an amount equal to the aggregate
principal amount of, all the Outstanding Debt Securities of such series or any
portion thereof, in either case having the same terms, including, without
limitation, the same original issue date, date or dates on which principal is
due and interest rate or method of determining interest.

                  "Holder," "Holder of Debt Securities" or other similar terms
                   ------    -------------------------
mean, with respect to a Registered Security, the Registered Holder.

                  "Indenture" means this instrument as originally executed, or,
                   ---------
if amended or supplemented as herein provided, as so amended or supplemented,
and shall include the form and terms of particular series of Debt Securities as
contemplated hereunder, whether or not a supplemental Indenture is entered into
with respect thereto.

                  "Issuer Order" means a written order of the Issuers, signed by
                   ------------
the Chairman of the Board, President or any Vice President of each of the
Managing General Partner and PAA Finance and by the Treasurer, Secretary, any
Assistant Treasurer or any Assistant Secretary of each of the Managing General
Partner and PAA Finance.

                  "Issuers" means the Partnership and PAA Finance, and, subject
                   -------
to the provisions of Article X, shall also include their successors and
permitted assigns.

                  "Lien" means, with respect to any asset, any mortgage, lien
                   ----
(statutory or otherwise), pledge, charge, security interest, hypothecation,
assignment for security, claim, preference, priority or encumbrance of any kind
in respect of such asset, whether or not filed, recorded or otherwise perfected
under applicable law, including any conditional sale or other title retention
agreement or any lease in the nature thereof, any option or other agreement to
grant a security interest in and any filing of or agreement to give any
financing statement under the Uniform Commercial Code (or equivalent statute) of
any jurisdiction, other than a precautionary financing statement respecting a
lease not intended as a security agreement.

                  "Managing General Partner" means Plains All American GP LLC, a
                   ------------------------
Delaware limited liability company and its successors and permitted assigns as
the general partner of the General Partner or as the business entity with the
ultimate authority to manage the business and operations of the Partnership.

                  "Officers' Certificate" means a certificate signed by the
                   ---------------------
Chairman of the Board of Directors, President or any Vice President of each of
the Managing General Partner and PAA Finance and by the Treasurer, Secretary,
any Assistant Treasurer or any Assistant Secretary of each of the Managing
General Partner and PAA Finance. Each such certificate shall include the
statements provided for in Section 12.05, if applicable.

                                       4
<PAGE>

                  "Opinion of Counsel" means an opinion in writing signed by
                   ------------------
legal counsel for the Issuers (which counsel may be an employee of the Issuers
or outside counsel for the Issuers). Each such opinion shall include the
statements provided for in Section 12.05, if applicable.

                  "Original Issue Discount Debt Security" means any Debt
                   -------------------------------------
Security which provides for an amount less than the principal amount thereof to
be due and payable upon a declaration or acceleration of the maturity thereof
pursuant to Section 6.01.

                  "Outstanding" when used with respect to any series of Debt
                   -----------
Securities, means, as of the date of determination, all Debt Securities of that
series theretofore authenticated and delivered under the Indenture, except:

                           (1)  Debt Securities of that series theretofore
                  canceled by the Trustee or delivered to the Trustee for
                  cancellation;

                           (2)  Debt Securities of that series for whose payment
                  or redemption money in the necessary amount has been
                  theretofore deposited with the Trustee or any paying agent
                  (other than the Partnership or PAA Finance) in trust or set
                  aside and segregated in trust by the Issuers (if either of the
                  Issuers shall act as its own paying agent) for the holders of
                  such Debt Securities; provided, that, if such Debt Securities
                  are to be redeemed, notice of such redemption has been duly
                  given pursuant to the Indenture or provision therefor
                  satisfactory to the Trustee has been made; and

                           (3)  Debt Securities of that series which have been
                  paid pursuant to Section 2.09 or in exchange for or in lieu of
                  which other Debt Securities have been authenticated and
                  delivered pursuant to the Indenture, other than any such Debt
                  Securities in respect of which there shall have been presented
                  to the Trustee proof satisfactory to it that such Debt
                  Securities are held by a bona fide purchaser in whose hands
                  such Debt Securities are valid obligations of the Issuers;

provided, however, that in determining whether the Holders of the requisite
--------  -------
principal amount of the Outstanding Debt Securities of any series have given any
request, demand, authorization, direction, notice, consent or waiver hereunder,
Debt Securities owned by the Issuers or any other obligor upon the Debt
Securities or any Subsidiary of the Issuers or of such other obligor shall be
disregarded and deemed not to be Outstanding, except that, in determining
whether the Trustee shall be protected in relying upon any such request, demand,
authorization, direction, notice, consent or waiver, only Debt Securities which
a Responsible Officer of the Trustee actually knows to be so owned shall be so
disregarded. Debt Securities so owned which have been pledged in good faith may
be regarded as Outstanding if the pledgee establishes to the satisfaction of the
Trustee the pledgee's right so to act with respect to such Debt Securities and
that the pledgee is not one of the Issuers or any other obligor upon the Debt
Securities or a Subsidiary of the Issuers or of such other obligor. In
determining whether the Holders of the requisite principal amount of outstanding
Debt Securities have given any request, demand, authorization, direction,
notice, consent or waiver hereunder, the principal amount of an Original Issue
Discount Debt Security that shall be deemed to be Outstanding for such purposes
shall be the amount of the principal thereof that would be due and payable as of
the date of such

                                       5
<PAGE>

determination upon a declaration of acceleration of the maturity thereof
pursuant to Section 6.01. In determining whether the Holders of the requisite
principal amount of the Outstanding Debt Securities of any series have given any
request, demand, authorization, direction, notice, consent or waiver hereunder,
the principal amount of a Debt Security denominated in one or more Foreign
Currencies or currency units that shall be deemed to be Outstanding for such
purposes shall be the Dollar Equivalent, determined in the manner provided as
contemplated by Section 2.03 on the date of original issuance of such Debt
Security, of the principal amount (or, in the case of any Original Issue
Discount Security, the Dollar Equivalent on the date of original issuance of
such Security of the amount determined as provided in the preceding sentence
above) of such Debt Security.

                  "PAA Finance" means PAA Finance Corp., a Delaware corporation,
                   -----------
and, subject to the provisions of Article X, shall also include its successors
and assigns.

                  "Partnership" means Plains All American Pipeline, L.P., a
                   -----------
Delaware limited partnership, and, subject to the provisions of Article X, shall
also include its successors and assigns.

                  "Payment Blockage Period" has the meaning set forth in Section
                   -----------------------
13.03.

                  "Person" means any individual, corporation, partnership, joint
                   ------
venture, association, limited liability company, joint stock company, trust,
unincorporated organization, government or any agency or political subdivision
thereof or any other entity.

                  "Place of Payment" means, when used with respect to the Debt
                   ----------------
Securities of any series, the place or places where the principal of, and
premium, if any, and interest on, the Debt Securities of that series are payable
as specified pursuant to Section 2.03.

                  "Registered Holder" means the Person in whose name a
                   -----------------
Registered Security is registered in the Debt Security Register (as defined in
Section 2.07(a)).

                  "Registered Security" means any Debt Security registered as to
                   -------------------
principal and interest in the Debt Security Register (as defined in Section
2.07(a)).

                  "Registrar" has the meaning set forth in Section 2.07(a).
                   ---------

                  "Representative" means the trustee, agent or representative
                   --------------
(if any) for an issue of Senior Indebtedness and, in the absence of any trustee,
agent or representative, it means the holder or holders of such issue.

                  "Responsible Officer" when used with respect to the Trustee,
                   -------------------
means any officer within the Corporate Trust Office of the Trustee or any other
officer of the Trustee performing functions similar to those performed by the
persons who at the time shall be such officers, and any other officer of the
Trustee to whom corporate trust matters are referred because of his knowledge of
and familiarity with the particular subject.

                  "Securities Act" means the Securities Act of 1933, as amended,
                   --------------
or any successor statute.

                                       6
<PAGE>

                  "Senior Indebtedness" means, as to any series of Debt
                   -------------------
Securities, the indebtedness of the Partnership identified as Senior
Indebtedness in the Board Resolution or supplemental Indenture setting forth the
terms of such series.

                  "Stated Maturity" means, at any time, with respect to any
                   ---------------
installment of interest or principal on any series of Debt Securities, the date
on which such payment of interest or principal was scheduled to be paid in the
original documentation governing such indebtedness or such later date as such
documentation shall provide at that time, and shall not include any contingent
obligations to repay, redeem or repurchase any such interest or principal prior
to the date originally scheduled for the payment thereof.

                  "Subordinated Debt Securities" has the meaning set forth in
                   ----------------------------
Section 13.03.

                  "Subsidiary" means, with respect to any Person:
                   ----------

                  (1) any corporation, association or other business entity of
which more than 50% of the Voting Stock is at the time owned or controlled,
directly or indirectly, by such Person or one or more of the other Subsidiaries
of that Person (or a combination thereof); and

                  (2) any partnership (whether general or limited) or limited
liability company (a) the sole general partner or the managing general partner
or managing member of which is such Person or a Subsidiary of such Person, or
(b) if there are more than a single general partner or member, either (i) the
only general partners or managing members of which are such Person and/or one or
more Subsidiaries of such Person (or any combination thereof) or (ii) such
Person owns or controls, directly or indirectly, a majority of the outstanding
general partner interests, member interests or other Voting Stock of such
partnership or limited liability company, respectively.

                  "Trust Indenture Act" (except as herein otherwise expressly
                   -------------------
provided) means the Trust Indenture Act of 1939 as in force at the date of the
Indenture as originally executed and, to the extent required by law, as amended,
or any successor statute.

                  "Trustee" initially means First Union National Bank and any
                   -------
other Person or Persons appointed as such from time to time pursuant to Section
7.08, and, subject to the provisions of Article VII, includes its or their
successors and assigns. If at any time there is more than one such Person,
"Trustee" as used with respect to the Debt Securities of any series shall mean
the Trustee with respect to the Debt Securities of that series.

                  "United States" means the United States of America (including
                   -------------
the States and the District of Columbia), its territories, its possessions and
other areas subject to its jurisdiction.

                  "U.S. Government Obligations" means securities that are (i)
                   ---------------------------
direct obligations of the United States for the payment of which its full faith
and credit is pledged; (ii) obligations of a Person controlled or supervised by
and acting as an agency or instrumentality of the United States, the payment of
which is unconditionally guaranteed as a full faith and credit obligation by the
United States, which, in either case, under clause (i) or (ii) above, are not
callable or redeemable at the option of the issuers thereof; or (iii) depository
receipts issued by a bank or trust company as custodian with respect to any such
U.S. Government Obligations or a specific

                                       7
<PAGE>

payment of interest on or principal of any such U.S. Government Obligation held
by such custodian for the account of the holder of a depository receipt,
provided that (except as required by law) such custodian is not authorized to
--------
make any deduction from the amount payable to the holder of such depository
receipt from any amount received by the custodian in respect of the U.S.
Government Obligation evidenced by such depository receipt.

                  "Voting Stock" of any Person as of any date means the Equity
                   ------------
Interests of such Person pursuant to which the holders thereof have the general
voting power under ordinary circumstances to elect at least a majority of the
board of directors, managers, general partners or trustees of any Person
(regardless of whether, at the time, Equity Interests of any other class or
classes shall have, or might have, voting power by reason of the occurrence of
any contingency) or, with respect to a partnership (whether general or limited),
any general partner interest in such partnership.

                  "Yield to Maturity" means the yield to maturity calculated at
                   -----------------
the time of issuance of a series of Debt Securities, or, if applicable, at the
most recent redetermination of interest on such series and calculated in
accordance with accepted financial practice.

                  SECTION 1.02.     Other Definitions.
                                    -----------------

Term                                              Section in which Defined
----                                              ------------------------

"Debt Security Register                                    2.07

"Defaulted Interest"                                       2.17

"Designated Currency"                                      2.18

"mandatory sinking fund payment"                           3.04

"optional sinking fund payment"                            3.04

"Successor Company"                                       10.01

                  SECTION 1.03.     Incorporation by Reference of Trust
                                    -----------------------------------
Indenture Act. The Indenture is subject to the mandatory provisions of the Trust
-------------
Indenture Act which are incorporated by reference in and made a part of the
Indenture. The following Trust Indenture Act terms have the following meanings:

                  "indenture securities" means the Debt Securities,
                   --------------------

                  "indenture security holder" means a Holder,
                   -------------------------

                  "indenture to be qualified" means the Indenture,
                   -------------------------

                  "indenture trustee" or "institutional trustee" means the
                   -----------------      ---------------------
Trustee and

                  "obligor" on the indenture securities means the Issuers and
                   -------
any other obligor on the Debt Securities.

                                       8
<PAGE>

                  All other Trust Indenture Act terms used in the Indenture that
are defined by the Trust Indenture Act, reference to another statute or defined
by rules of the Commission have the meanings assigned to them by such
definitions.

                  SECTION 1.04.     Rules of Construction. Unless the context
                                    ---------------------
otherwise requires:

                  (1)      a term has the meaning assigned to it;

                  (2)      an accounting term not otherwise defined has the
meaning assigned to it in accordance with GAAP;

                  (3)      "or" is not exclusive;

                  (4)      "including" means including without limitation; and

                  (5)      words in the singular include the plural and words in
the plural include the singular.

                                  ARTICLE II

                                Debt Securities
                                ---------------

                  SECTION 2.01.     Forms Generally. The Debt Securities of each
                                    ---------------
series shall be in substantially the form established without the approval of
any Holder by or pursuant to a Board Resolution of each of the Issuers or in one
or more Indentures supplemental hereto, in each case with such appropriate
insertions, omissions, substitutions and other variations as are required or
permitted by the Indenture, and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as the Issuers
may deem appropriate (and, if not contained in a supplemental Indenture entered
into in accordance with Article IX, as are not prohibited by the provisions of
the Indenture) or as may be required or appropriate to comply with any law or
with any rules made pursuant thereto or with any rules of any securities
exchange on which such series of Debt Securities may be listed, or to conform to
general usage, or as may, consistently herewith, be determined by the officers
executing such Debt Securities as evidenced by their execution of the Debt
Securities.

                  The definitive Debt Securities of each series shall be
printed, lithographed or engraved on steel engraved borders or may be produced
in any other manner, all as determined by the officers executing such Debt
Securities, as evidenced by their execution of such Debt Securities.

                  SECTION 2.02.     Form of Trustee's Certificate of
                                    --------------------------------
Authentication. The Trustee's Certificate of Authentication on all Debt
--------------
Securities authenticated by the Trustee shall be in substantially the following
form:

                                       9
<PAGE>

                    TRUSTEE'S CERTIFICATE OF AUTHENTICATION

                  This is one of the Debt Securities of the series designated
therein referred to in the within-mentioned Indenture.

                                             __________________________,
                                                as Trustee

                                             By _______________________
                                                Authorized Signatory

                                             Dated: ___________________

                  SECTION 2.03.     Principal Amount; Issuable in Series. The
                                    ------------------------------------
aggregate principal amount of Debt Securities which may be issued, executed,
authenticated, delivered and outstanding under the Indenture is unlimited.

                  The Debt Securities may be issued in one or more series. There
shall be established, without the approval of any Holders, in or pursuant to a
Board Resolution of each of the Issuers and set forth in an Officers'
Certificate of each of the Issuers, or established in one or more Indentures
supplemental hereto, prior to the issuance of Debt Securities of any series any
or all of the following:

                  (1)      the title of the Debt Securities of the series (which
         shall distinguish the Debt Securities of the series from all other Debt
         Securities);

                  (2)      any limit upon the aggregate principal amount of the
         Debt Securities of the series which may be authenticated and delivered
         under the Indenture (except for Debt Securities authenticated and
         delivered upon registration of transfer of, or in exchange for, or in
         lieu of, other Debt Securities of the series pursuant to this Article
         II);

                  (3)      the date or dates on which the principal and premium,
         if any, of the Debt Securities of the series are payable;

                  (4)      the rate or rates (which may be fixed or variable) at
         which the Debt Securities of the series shall bear interest, if any, or
         the method of determining such rate or rates, the date or dates from
         which such interest shall accrue, the interest payment dates on which
         such interest shall be payable, or the method by which such date will
         be determined, and in the case of Registered Securities, the record
         dates for the determination of Holders thereof to whom such interest is
         payable; and the basis upon which interest will be calculated if other
         than that of a 360-day year of twelve thirty-day months;

                  (5)      the Place or Places of Payment, if any, in addition
         to or instead of the Corporate Trust Office of the Trustee where the
         principal of, and interest on, Debt Securities of the series shall be
         payable;

                                       10
<PAGE>

          (6)  the price or prices at which, the period or periods within which
     and the terms and conditions upon which Debt Securities of the series may
     be redeemed, in whole or in part, at the option of the Issuers or
     otherwise;

          (7)  the obligation, if any, of the Issuers to redeem, purchase or
     repay Debt Securities of the series pursuant to any sinking fund or
     analogous provisions or at the option of a Holder thereof, and the price or
     prices at which and the period or periods within which and the terms and
     conditions upon which Debt Securities of the series shall be redeemed,
     purchased or repaid, in whole or in part, pursuant to such obligations;

          (8)  the terms, if any, upon which the Debt Securities of the series
     may be convertible into or exchanged for Equity Interests, other Debt
     Securities or other securities of any kind of the Partnership, PAA Finance
     or any other obligor or issuer and the terms and conditions upon which such
     conversion or exchange shall be effected, including the initial conversion
     or exchange price or rate, the conversion or exchange period and any other
     provision in addition to or in lieu of those described herein;

          (9)  if other than denominations of $1,000 and any integral multiple
     thereof, the denominations in which Debt Securities of the series shall be
     issuable;

          (10) if the amount of principal of or any premium or interest on Debt
     Securities of the series may be determined with reference to an index or
     pursuant to a formula, the manner in which such amounts will be determined;

          (11) if the principal amount payable at the Stated Maturity of Debt
     Securities of the series will not be determinable as of any one or more
     dates prior to such Stated Maturity, the amount which will be deemed to be
     such principal amount as of any such date for any purpose, including the
     principal amount thereof which will be due and payable upon any maturity
     other than the Stated Maturity or which will be deemed to be Outstanding as
     of any such date (or, in any such case, the manner in which such deemed
     principal amount is to be determined); and the manner of determining the
     equivalent thereof in the currency of the United States of America for
     purposes of the definition of Dollar Equivalent;

          (12) any changes or additions to Article XI or XIII or in any defined
     term used in either Article XI or XIII;

          (13) if other than Dollars, the coin or Currency or Currencies or
     units of two or more Currencies in which payment of the principal of and
     premium, if any, and interest on, Debt Securities of the series shall be
     payable;

          (14) if other than the principal amount thereof, the portion of the
     principal amount of Debt Securities of the series which shall be payable
     upon declaration of acceleration of the maturity thereof pursuant to
     Section 6.01 or provable in bankruptcy pursuant to Section 6.02;

          (15) the terms, if any, of the transfer, mortgage, pledge or
     assignment as security for the Debt Securities of the series of any
     properties, assets, moneys, proceeds,

                                       11
<PAGE>

     securities or other collateral, including whether certain provisions of the
     Trust Indenture Act are applicable and any corresponding changes to
     provisions of the Indenture as currently in effect;

          (16) any addition to or change in the Events of Default with respect
     to the Debt Securities of the series and any change in the right of the
     Trustee or the Holders to declare the principal of and interest on, such
     Debt Securities due and payable;

          (17) if the Debt Securities of the series shall be issued in whole or
     in part in the form of a Global Security or Securities, the terms and
     conditions, if any, upon which such Global Security or Securities may be
     exchanged in whole or in part for other individual Debt Securities in
     definitive registered form; and the Depositary for such Global Security or
     Securities and the form of any legend or legends to be borne by any such
     Global Security or Securities in addition to or in lieu of the legend
     referred to in Section 2.15;

          (18) trustees, authenticating or paying agents, transfer agents or
     registrars;

          (19) the applicability of, and any addition to or change in the
     covenants and definitions currently set forth in the Indenture or in the
     terms currently set forth in Article X, including conditioning any merger,
     conveyance, transfer or lease permitted by Article X upon the satisfaction
     of an indebtedness coverage standard by the Issuers and any Successor
     Company (as defined in Article X);

          (20) the terms, if any, of any guarantee of the payment of principal
     of, and premium, if any, and interest on, Debt Securities of the series and
     any corresponding changes to the provisions of the Indenture as currently
     in effect;

          (21) with regard to Debt Securities of the series that do not bear
     interest, the dates for certain required reports to the Trustee;

          (22) any other terms of the Debt Securities of the series (which terms
     shall not be prohibited by the provisions of the Indenture); and

          (23) applicable CUSIP Numbers.

          All Debt Securities of any one series appertaining thereto shall be
substantially identical except as to denomination and except as may otherwise be
provided in or pursuant to such Board Resolutions and as set forth in such
Officers' Certificates or in any such Indenture supplemental hereto.

          SECTION 2.04.  Execution of Debt Securities. The Debt Securities shall
                         ----------------------------
be signed on behalf of the Partnership by the Chairman of the Board, the
President or a Vice President of the Managing General Partner, and shall be
signed on behalf of PAA Finance by its Chairman of the Board, its President or a
Vice President. Such signatures upon the Debt Securities may be the manual or
facsimile signatures of the present or any future such authorized officers and
may be imprinted or otherwise reproduced on the Debt Securities. The seals of
the Issuers, if any, may be in the form of a facsimile thereof and may be
impressed, affixed, imprinted or otherwise reproduced on the Debt Securities.

                                       12
<PAGE>

          Only such Debt Securities as shall bear thereon a certificate of
authentication substantially in the form hereinbefore recited, signed manually
by the Trustee, shall be entitled to the benefits of the Indenture or be valid
or obligatory for any purpose. Such certificate by the Trustee upon any Debt
Security executed by the Issuers shall be conclusive evidence that the Debt
Security so authenticated has been duly authenticated and delivered hereunder.

          In case any officer of either of the Managing General Partner or PAA
Finance who shall have signed any of the Debt Securities shall cease to be such
officer before the Debt Securities so signed shall have been authenticated and
delivered by the Trustee, or disposed of by the Issuers, such Debt Securities
nevertheless may be authenticated and delivered or disposed of as though the
Person who signed such Debt Securities had not ceased to be such officer of the
Managing General Partner or PAA Finance; and any Debt Security may be signed on
behalf of the Issuers by such Persons as, at the actual date of the execution of
such Debt Security, shall be the proper officers of the Managing General Partner
or PAA Finance, as applicable, although at the date of such Debt Security or of
the execution of the Indenture any such Person was not such officer.

          SECTION 2.05.  Authentication and Delivery of Debt Securities. At any
                         ----------------------------------------------
time and from time to time after the execution and delivery of the Indenture,
the Issuers may deliver Debt Securities of any series executed by the Issuers to
the Trustee for authentication, and the Trustee shall thereupon authenticate and
deliver said Debt Securities to or upon an Issuer Order. The Debt Securities
shall be dated the date of their authentication. In authenticating such Debt
Securities and accepting the additional responsibilities under the Indenture in
relation to such Debt Securities, the Trustee shall be entitled to receive, and
(subject to Section 7.01) shall be fully protected in relying upon:

          (1)  a copy of any Board Resolution of each of the Issuers, certified
     by the Secretary or Assistant Secretary of each of the Issuers, authorizing
     the terms of issuance of any series of Debt Securities;

          (2)  an executed supplemental Indenture, if any;

          (3)  an Officers' Certificate; and

          (4)  an Opinion of Counsel prepared in accordance with Section 12.05
     substantially to the effect that:

               (a)  the form of such Debt Securities has been established by or
          pursuant to a Board Resolution of each of the Issuers or by a
          supplemental Indenture as permitted by Section 2.01 in conformity with
          the provisions of the Indenture;

               (b)  the terms of such Debt Securities have been established by
          or pursuant to a Board Resolution of each of the Issuers or by a
          supplemental Indenture as permitted by Section 2.03 in conformity with
          the provisions of the Indenture; and

                                       13
<PAGE>

               (c)  such Debt Securities, when authenticated and delivered by
          the Trustee and issued by the Issuers in the manner and subject to any
          conditions specified in such Opinion of Counsel, will constitute valid
          and legally binding obligations of the Issuers, enforceable in
          accordance with their terms except as (i) the enforceability thereof
          may be limited by bankruptcy, insolvency or similar laws affecting the
          enforcement of creditors' rights generally and (ii) rights of
          acceleration and the availability of equitable remedies may be limited
          by equitable principles of general applicability.

          Such Opinion of Counsel need express no opinion as to whether a court
in the United States would render a money judgment in a Currency other than
Dollars.

          The Trustee shall have the right to decline to authenticate and
deliver any Debt Securities under this Section 2.05 if the Trustee, being
advised by counsel, determines that such action may not lawfully be taken or if
the Trustee in good faith by its board of directors or trustees, executive
committee or a trust committee of directors, trustees or vice presidents shall
determine that such action would expose the Trustee to personal liability to
existing Holders.

          The Trustee may appoint an authenticating agent reasonably acceptable
to the Issuers to authenticate Debt Securities of any series. Unless limited by
the terms of such appointment, an authenticating agent may authenticate Debt
Securities whenever the Trustee may do so. Each reference in the Indenture to
authentication by the Trustee includes authentication by such agent. An
authenticating agent has the same rights as any Registrar, paying agent or agent
for service of notices and demands.

          SECTION 2.06.  Denomination of Debt Securities. Unless otherwise
                         -------------------------------
provided in the form of Debt Security for any series, the Debt Securities of
each series shall be issuable only as Registered Securities in such
denominations as shall be specified or contemplated by Section 2.03. In the
absence of any such specification with respect to the Debt Securities of any
series, the Debt Securities of such series shall be issuable in denominations of
$1,000 and any integral multiple thereof.

          SECTION 2.07.  General Provisions for Registration of Transfer and
                         ---------------------------------------------------
Exchange. (a) The Issuers shall keep or cause to be kept a register for each
--------
series of Registered Securities issued hereunder (hereinafter collectively
referred to as the "Debt Security Register"), in which, subject to such
reasonable regulations as they may prescribe, the Issuers shall provide for the
registration of Registered Securities and the transfer of Registered Securities
as in this Article II provided. At all reasonable times the Debt Security
Register shall be open for inspection by the Trustee. Subject to Section 2.15,
upon due presentment for registration of transfer of any Registered Security at
any office or agency to be maintained by the Issuers in accordance with the
provisions of Section 4.02, the Issuers shall execute and the Trustee shall
authenticate and deliver in the name of the transferee or transferees a new
Registered Security or Registered Securities of authorized denominations for a
like aggregate principal amount.

          Unless and until otherwise determined by a Board Resolution of each of
the Issuers, the register of the Issuers for the purpose of registration,
exchange or registration of transfer of the Registered Securities shall be kept
at the Corporate Trust Office of the Trustee

                                       14
<PAGE>

and, for this purpose, the Trustee shall be designated "Registrar". No prior
notice to the Holders of Debt Securities is required to effect the designation
of a substitute Registrar by the Issuers.

          Registered Securities of any series (other than a Global Security) may
be exchanged for a like aggregate principal amount of Registered Securities of
the same series of other authorized denominations. Subject to Section 2.15,
Registered Securities to be exchanged shall be surrendered at the office or
agency to be maintained by the Issuers as provided in Section 4.02, and the
Issuers shall execute and the Trustee shall authenticate and deliver in exchange
therefor the Registered Security or Registered Securities that the Holder making
the exchange shall be entitled to receive.

          (b)  All Registered Securities presented or surrendered for
registration of transfer, exchange or payment shall (if so required by the
Issuers, the Trustee or the Registrar) be duly endorsed or be accompanied by a
written instrument or instruments of transfer, in form satisfactory to the
Issuers, the Trustee and the Registrar, duly executed by the Registered Holder
or his attorney duly authorized in writing.

          All Debt Securities issued in exchange for or upon transfer of Debt
Securities shall be the legal, valid and binding obligations of the Issuers,
evidencing the same debt, and entitled to the same benefits under the Indenture
as the Debt Securities surrendered for such exchange or transfer.

          No service charge shall be made for any exchange or registration of
transfer of Debt Securities (except as provided by Section 2.09), but the
Issuers may require payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto, other than those
expressly provided in the Indenture to be made at the Issuers' own expense or
without expense or without charge to the Holders.

          The Issuers shall not be required (a) to issue, register the transfer
of or exchange any Debt Securities of a series either (i) during a period
beginning 15 Business Days next preceding any selection for redemption or
repurchase of Debt Securities of such series and ending on the close of business
on the day of giving the relevant notice of redemption or repurchase or (ii)
between a record date and the next succeeding interest payment date, or (b) to
register the transfer of or exchange any Debt Security called for redemption or
repurchase (except, in the case of Debt Securities to be redeemed or repurchased
in part, the portion not to be redeemed or repurchased).

          Specific procedures for registration of transfer and exchange of any
series of Debt Securities may be set forth in the applicable supplemental
Indenture for such Debt Securities.

          SECTION 2.08.  Temporary Debt Securities. Pending the preparation of
                         -------------------------
definitive Debt Securities of any series, the Issuers may execute and the
Trustee shall authenticate and deliver temporary Debt Securities (printed,
lithographed, photocopied, typewritten or otherwise produced) of any authorized
denomination, and substantially in the form of the definitive Debt Securities in
lieu of which they are issued, and with such omissions, insertions and
variations as may be appropriate for temporary Debt Securities, all as may be
determined by the Issuers with the concurrence of the Trustee. Temporary Debt
Securities may

                                       15
<PAGE>

contain such reference to any provisions of the Indenture as may be appropriate.
Every temporary Debt Security shall be executed by the Issuers and be
authenticated by the Trustee upon the same conditions and in substantially the
same manner, and with like effect, as the definitive Debt Securities.

          If temporary Debt Securities of any series are issued, the Issuers
will cause definitive Debt Securities of such series to be prepared without
unreasonable delay. After the preparation of definitive Debt Securities of such
series, the temporary Debt Securities of such series shall be exchangeable for
definitive Debt Securities of such series upon surrender of the temporary Debt
Securities of such series at the office or agency of the Issuers at a Place of
Payment for such series, without charge to the Holder thereof, except as
provided in Section 2.07 in connection with a transfer, and upon surrender for
cancellation of any one or more temporary Debt Securities of any series, the
Issuers shall execute and the Trustee shall authenticate and deliver in exchange
therefor a like principal amount of definitive Debt Securities of the same
series of authorized denominations and of like tenor. Until so exchanged,
temporary Debt Securities of any series shall in all respects be entitled to the
same benefits under the Indenture as definitive Debt Securities of such series,
except as otherwise specified as contemplated by Section 2.03(17) with respect
to the payment of interest on Global Securities in temporary form.

          Upon any exchange of a portion of a temporary Global Security for a
definitive Global Security or for the individual Debt Securities represented
thereby pursuant to Section 2.07 or this Section 2.08, the temporary Global
Security shall be endorsed by the Trustee to reflect the reduction of the
principal amount evidenced thereby, whereupon the principal amount of such
temporary Global Security shall be reduced for all purposes by the amount so
exchanged and endorsed.

          SECTION 2.09.  Mutilated, Destroyed, Lost or Stolen Debt Securities.
                         ----------------------------------------------------
If (i) any mutilated Debt Security is surrendered to the Trustee at the
Corporate Trust Office of the Trustee (in the case of Registered Securities) or
(ii) the Issuers and the Trustee receive evidence to their satisfaction of the
destruction, loss or theft of any Debt Security, and there is delivered to the
Issuers and the Trustee such security or indemnity as may be required by them to
save each of them and any paying agent harmless, and neither the Issuers nor the
Trustee receives written notice that such Debt Security has been acquired by a
bona fide purchaser, then the Issuers shall execute and, upon an Issuer Order,
the Trustee shall authenticate and deliver, in exchange for or in lieu of any
such mutilated, destroyed, lost or stolen Debt Security, a new Debt Security of
the same series of like tenor, form, terms and principal amount, bearing a
number not contemporaneously Outstanding. Upon the issuance of any substituted
Debt Security, the Issuers may require the payment of a sum sufficient to cover
any tax or other governmental charge that may be imposed in relation thereto and
any other expenses connected therewith. In case any Debt Security which has
matured or is about to mature or which has been called for redemption shall
become mutilated or be destroyed, lost or stolen, the Issuers may, instead of
issuing a substituted Debt Security, pay or authorize the payment of the same
(without surrender thereof except in the case of a mutilated Debt Security) if
the applicant for such payment shall furnish the Issuers and the Trustee with
such security or indemnity as either may require to save it harmless from all
risk, however remote, and, in case of destruction, loss or theft, evidence to
the satisfaction of the Issuers and the Trustee of the destruction, loss or
theft of such Debt Security and of the ownership thereof.

                                       16
<PAGE>

          Every substituted Debt Security of any series issued pursuant to the
provisions of this Section 2.09 by virtue of the fact that any Debt Security is
destroyed, lost or stolen shall constitute an original additional contractual
obligation of the Issuers, whether or not the destroyed, lost or stolen Debt
Security shall be found at any time, and shall be entitled to all the benefits
of the Indenture equally and proportionately with any and all other Debt
Securities of that series duly issued hereunder. All Debt Securities shall be
held and owned upon the express condition that the foregoing provisions are
exclusive with respect to the replacement or payment of mutilated, destroyed,
lost or stolen Debt Securities, and shall preclude any and all other rights or
remedies, notwithstanding any law or statute existing or hereafter enacted to
the contrary with respect to the replacement or payment of negotiable
instruments or other securities without their surrender, in each case to the
fullest extent permitted by law.

          SECTION 2.10.  Cancellation of Surrendered Debt Securities. All Debt
                         -------------------------------------------
Securities surrendered for payment, redemption, registration of transfer or
exchange shall, if surrendered to the Iss uers or any paying agent or a
Registrar, be delivered to the Trustee for cancellation by it, or if surrendered
to the Trustee, shall be canceled by it, and no Debt Securities shall be issued
in lieu thereof except as expressly permitted by any of the provisions of the
Indenture. All canceled Debt Securities held by the Trustee shall be disposed of
by the Trustee in its customary manner. On request of the Issuers, the Trustee
shall deliver to the Issuers canceled Debt Securities held by the Trustee. If
the Issuers shall acquire any of the Debt Securities, however, such acquisition
shall not operate as a redemption or satisfaction of the indebtedness
represented thereby unless and until the same are delivered or surrendered to
the Trustee for cancellation. The Issuers may not issue new Debt Securities to
replace Debt Securities it has redeemed, paid or delivered to the Trustee for
cancellation.

          SECTION 2.11.  Provisions of the Indenture and Debt Securities for the
                         -------------------------------------------------------
Sole Benefit of the Parties and the Holders. Nothing in the Indenture or in the
-------------------------------------------
Debt Securities, expressed or implied, shall give or be construed to give to any
Person, other than the parties hereto, the Holders or any Registrar or paying
agent, any legal or equitable right, remedy or claim under or in respect of the
Indenture, or under any covenant, condition or provision herein contained, all
its covenants, conditions and provisions being for the sole benefit of the
parties hereto, the Holders and any Registrar and paying agents.

          SECTION 2.12.  Payment of Interest; Rights Preserved. (a) Interest on
                         -------------------------------------
any Registered Security that is payable and is punctually paid or duly provided
for on any interest payment date shall be paid to the Person in whose name such
Registered Security is registered at the close of business on the regular record
date for such interest notwithstanding the cancellation of such Registered
Security upon any transfer or exchange subsequent to the regular record date.
Payment of interest on Registered Securities shall be made at the Corporate
Trust Office of the Trustee (except as otherwise specified pursuant to Section
2.03), or at the option of the Issuers, by check mailed to the address of the
Person entitled thereto as such address shall appear in the Debt Security
Register or, if provided pursuant to Section 2.03 and in accordance with
arrangements satisfactory to the Trustee, at the option of the Registered Holder
by wire transfer to an account designated by the Registered Holder.

          (b)  Subject to the foregoing provisions of this Section 2.12 and
Section 2.17, each Debt Security of a particular series delivered under the
Indenture upon registration of

                                       17
<PAGE>

transfer of or in exchange for or in lieu of any other Debt Security of the same
series shall carry the rights to interest accrued and unpaid, and to accrue,
which were carried by such other Debt Security.

          SECTION 2.13.  Securities Denominated in Foreign Currencies. (a)
                         --------------------------------------------
Except as otherwise specified pursuant to Section 2.03 for Registered Securities
of any series, payment of the principal of, and premium, if any, and interest
on, Registered Securities of such series will be made in Dollars.

          (b)  For the purposes of calculating the principal amount of Debt
Securities of any series denominated in a Foreign Currency or in units of two or
more Foreign Currencies for any purpose under the Indenture, the principal
amount of such Debt Securities at any time Outstanding shall be deemed to be the
Dollar Equivalent of such principal amount as of the date of any such
calculation.

          In the event any Foreign Currency or currencies or units of two or
more Currencies in which any payment with respect to any series of Debt
Securities may be made ceases to be a freely convertible Currency on United
States Currency markets, for any date thereafter on which payment of principal
of, or premium, if any, or interest on, the Debt Securities of a series is due,
the Issuers shall select the Currency of payment for use on such date, all as
provided in the Debt Securities of such series. In such event, the Issuers
shall, as provided in the Debt Securities of such series, notify the Trustee of
the Currency which they have selected to constitute the funds necessary to meet
the Issuers' obligations or such payment date and of the amount of such Currency
to be paid. Such amount shall be determined as provided in the Debt Securities
of such series. The payment to the Trustee with respect to such payment date
shall be made by the Issuers solely in the Currency so selected.

          SECTION 2.14.  Wire Transfers. Notwithstanding any other provision to
                         --------------
the contrary in the Indenture, the Issuers may make any payment of monies
required to be deposited with the Trustee on account of principal of, or
premium, if any, or interest on, the Debt Securities (whether pursuant to
optional or mandatory redemption payments, interest payments or otherwise) by
wire transfer of immediately available funds to an account designated by the
Trustee on or before the date such moneys are to be paid to the Holders of the
Debt Securities in accordance with the terms hereof.

          SECTION 2.15.  Securities Issuable in the Form of a Global Security.
                         ----------------------------------------------------
(a) If the Issuers shall establish pursuant to Sections 2.01 and 2.03 that the
Debt Securities of a particular series are to be issued in whole or in part in
the form of one or more Global Securities, then the Issuers shall execute and
the Trustee or its agent shall, in accordance with Section 2.05, authenticate
and deliver, such Global Security or Securities, which (i) shall represent, and
shall be denominated in an amount equal to the aggregate principal amount of,
the Outstanding Debt Securities of such series to be represented by such Global
Security or Securities, or such portion thereof as the Issuers shall specify in
an Officers' Certificate, (ii) shall be registered in the name of the Depositary
for such Global Security or securities or its nominee, (iii) shall be delivered
by the Trustee or its agent to the Depositary or pursuant to the Depositary's
instruction and (iv) shall bear a legend substantially to the following effect:
"Unless and until it is exchanged in whole or in part for the individual Debt
Securities represented hereby, this Global Security may not be

                                       18
<PAGE>

transferred except as a whole by the Depositary to a nominee of the Depositary
or by a nominee of the Depositary to the Depositary or another nominee of the
Depositary or by the Depositary or any such nominee to a successor Depositary or
a nominee of such successor Depositary", or such other legend as may then be
required by the Depositary for such Global Security or Securities.

          (b)  Notwithstanding any other provision of this Section 2.15 or of
Section 2.07 to the contrary, and subject to the provisions of paragraph (c)
below, unless the terms of a Global Security expressly permit such Global
Security to be exchanged in whole or in part for definitive Debt Securities in
registered form, a Global Security may be transferred, in whole but not in part
and in the manner provided in Section 2.07, only by the Depositary to a nominee
of the Depositary for such Global Security, or by a nominee of the Depositary to
the Depositary or another nominee of the Depositary, or by the Depositary or a
nominee of the Depositary to a successor Depositary for such Global Security
selected or approved by the Issuers, or to a nominee of such successor
Depositary.

          (c) (i) If at any time the Depositary for a Global Security or
Securities notifies the Issuers that it is unwilling or unable to continue as
Depositary for such Global Security or Securities or if at any time the
Depositary for the Debt Securities for such series shall no longer be eligible
or in good standing under the Exchange Act or other applicable statute, rule or
regulation, the Issuers shall appoint a successor Depositary with respect to
such Global Security or Securities. If a successor Depositary for such Global
Security or Securities is not appointed by the Issuers within 90 days after the
Issuers receive such notice or become aware of such ineligibility, the Issuers
shall execute, and the Trustee or its agent, upon receipt of an Issuer Order for
the authentication and delivery of such individual Debt Securities of such
series in exchange for such Global Security, will authenticate and deliver,
individual Debt Securities of such series of like tenor and terms in definitive
form in an aggregate principal amount equal to the principal amount of the
Global Security in exchange for such Global Security or Securities.

          (ii) The Issuers may at any time and in their sole discretion
determine that the Debt Securities of any series or portion thereof issued or
issuable in the form of one or more Global Securities shall no longer be
represented by such Global Security or Securities. In such event the Issuers
will execute, and the Trustee, upon receipt of an Issuer Order for the
authentication and delivery of individual Debt Securities of such series in
exchange in whole or in part for such Global Security, will authenticate and
deliver individual Debt Securities of such series of like tenor and terms in
definitive form in an aggregate principal amount equal to the principal amount
of such series or portion thereof in exchange for such Global Security or
Securities.

          (iii) If specified by the Issuers pursuant to Sections 2.01 and 2.03
with respect to Debt Securities issued or issuable in the form of a Global
Security, the Depositary for such Global Security may surrender such Global
Security in exchange in whole or in part for individual Debt Securities of such
series of like tenor and terms in definitive form on such terms as are
acceptable to the Issuers, the Trustee and such Depositary. Thereupon the
Issuers shall execute, and the Trustee or its agent upon receipt of an Issuer
Order for the authentication and delivery of definitive Debt Securities of such
series shall authenticate and deliver, without service charge, (1) to each
Person specified by such Depositary a new Debt Security or Securities of the
same series of like tenor and terms and of any authorized denomination as
requested by

                                       19
<PAGE>

such Person in aggregate principal amount equal to and in exchange for such
Person's beneficial interest in the Global Security, and (2) to such Depositary
a new Global Security of like tenor and terms and in an authorized denomination
equal to the difference, if any, between the principal amount of the surrendered
Global Security and the aggregate principal amount of Debt Securities delivered
to Holders thereof, unless such Global Security is endorsed by the Trustee or
other custodian to reflect a reduction of such aggregate principal amount, in
which case no new Global Security need be authenticated and delivered.

          (iv) In any exchange provided for in any of the preceding three
paragraphs, the Issuers will execute and the Trustee or its agent will
authenticate and deliver individual Debt Securities. Upon the exchange of the
entire principal amount of a Global Security for individual Debt Securities,
such Global Security shall be canceled by the Trustee or its agent. Except as
provided in the preceding paragraph, Registered Securities issued in exchange
for a Global Security pursuant to this Section 2.15 shall be registered in such
names and in such authorized denominations as the Depositary for such Global
Security, pursuant to instructions from its direct or indirect participants or
otherwise, shall instruct the Trustee or the Registrar. The Trustee or the
Registrar shall deliver such Registered Securities to the Persons in whose names
such Registered Securities are so registered.

          (v)  Payments in respect of the principal of and interest on any Debt
Securities registered in the name of the Depositary or its nominee will be
payable to the Depositary or such nominee in its capacity as the registered
owner of such Global Security. The Issuers and the Trustee may treat the Person
in whose name the Debt Securities, including the Global Security, are registered
as the owner thereof for the purpose of receiving such payments and for any and
all other purposes whatsoever. None of the Issuers, the Trustee, any Registrar,
the paying agent or any agent of the Issuers or the Trustee will have any
responsibility or liability for (a) any aspect of the records relating to or
payments made on account of the beneficial ownership interests of the Global
Security by the Depositary or its nominee or any of the Depositary's direct or
indirect participants, or for maintaining, supervising or reviewing any records
of the Depositary, its nominee or any of the Depositary's direct or indirect
participants relating to the beneficial ownership interests of the Global
Security, (b) the payments to the beneficial owners of the Global Security of
amounts paid to the Depositary or its nominee, or (c) any other matter relating
to the actions and practices of the Depositary, its nominee or any of the
Depositary's direct or indirect participants. None of the Issuers, the Trustee
or any such agent will be liable for any delay by the Depositary, its nominee,
or any of the Depositary's direct or indirect participants in identifying the
beneficial owners of the Debt Securities, and the Issuers and the Trustee may
conclusively rely on, and will be protected in relying on, instructions from the
Depositary or its nominee for all purposes (including with respect to the
registration and delivery, and the respective principal amounts, of the Debt
Securities to be issued).

          SECTION 2.16.  Medium Term Securities. Notwithstanding any contrary
                         ----------------------
provision herein, if all Debt Securities of a series are not to be originally
issued at one time, it shall not be necessary for the Issuers to deliver to the
Trustee an Officers' Certificate, a Board Resolution, a supplemental Indenture,
an Opinion of Counsel or a written order or any other document otherwise
required pursuant to Section 2.01, 2.03, 2.05 or 12.05 at or prior to the time
of authentication of each Debt Security of such series if such documents are
delivered to the Trustee or its agent at or prior to the authentication upon
original issuance of the first such Debt

                                       20
<PAGE>

Security of such series to be issued; provided, that any subsequent request by
                                      --------
the Issuers to the Trustee to authenticate Debt Securities of such series upon
original issuance shall constitute a representation and warranty by the Issuers
that, as of the date of such request, the statements made in the Officers'
Certificate delivered pursuant to Section 2.05 or 12.05 shall be true and
correct as if made on such date and that the Opinion of Counsel delivered at or
prior to such time of authentication of an original issuance of Debt Securities
shall specifically state that it shall relate to all subsequent issuances of
Debt Securities of such series that are identical to the Debt Securities issued
in the first issuance of Debt Securities of such series.

                  An Issuer Order delivered by the Issuers to the Trustee in the
circumstances set forth in the preceding paragraph may provide that Debt
Securities which are the subject thereof will be authenticated and delivered by
the Trustee or its agent on original issue from time to time upon the written
order of Persons designated in such written order and that such Persons are
authorized to determine, consistent with the Officers' Certificates,
supplemental Indenture or the applicable Board Resolutions relating to such
written order, such terms and conditions of such Debt Securities as are
specified in such Officers' Certificates, supplemental Indenture or such Board
Resolutions.

                  SECTION 2.17. Defaulted Interest. Any interest on any Debt
                                ------------------
Security of a particular series which is payable, but is not punctually paid or
duly provided for, on the dates and in the manner provided in the Debt
Securities of such series and in the Indenture (herein called "Defaulted
Interest") shall forthwith cease to be payable to the Registered Holder thereof
on the relevant record date by virtue of having been such Registered Holder, and
such Defaulted Interest may be paid by the Issuers, at their election in each
case, as provided in clause (i) or (ii) below:

                  (i)  The Issuers may elect to make payment of any Defaulted
         Interest to the Persons in whose names the Registered Securities of
         such series are registered at the close of business on a special record
         date for the payment of such Defaulted Interest, which shall be fixed
         in the following manner: The Issuers shall notify the Trustee in
         writing of the amount of Defaulted Interest proposed to be paid on each
         such Registered Security of such series and the date of the proposed
         payment, and at the same time the Issuers shall deposit with the
         Trustee an amount of money equal to the aggregate amount proposed to be
         paid in respect of such Defaulted Interest or shall make arrangements
         satisfactory to the Trustee for such deposit prior to the date of the
         proposed payment, such money when deposited to be held in trust for the
         benefit of the Persons entitled to such Defaulted Interest as in this
         clause provided. Thereupon the Trustee shall fix a special record date
         for the payment of such Defaulted Interest which shall be not more than
         15 days and not less than 10 days prior to the date of the proposed
         payment and not less than 10 days after the receipt by the Trustee of
         the notice of the proposed payment. The Trustee shall promptly notify
         the Issuers of such special record date and, in the name and at the
         expense of the Issuers, shall cause notice of the proposed payment of
         such Defaulted Interest and the special record date therefor to be
         mailed, first class postage prepaid, to each Holder thereof at its
         address as it appears in the Debt Security Register, not less than 10
         days prior to such special record date. Notice of the proposed payment
         of such Defaulted Interest and the special record date therefor having
         been so mailed, such Defaulted Interest shall be paid to the Persons in
         whose names the Registered

                                       21
<PAGE>

         Securities of such series are registered at the close of business on
         such special record date.

                  (ii)  The Issuers may make payment of any Defaulted Interest
         on the Registered Securities of such series in any other lawful manner
         not inconsistent with the requirements of any securities exchange on
         which the Registered Securities of such series may be listed, and upon
         such notice as may be required by such exchange, if, after notice given
         by the Issuers to the Trustee of the proposed payment pursuant to this
         clause, such manner of payment shall be deemed practicable by the
         Trustee.

                  SECTION 2.18. Judgments. The Issuers may provide pursuant to
                                ---------
Section 2.03 for Debt Securities of any series that (a) the obligation, if any,
of the Issuers to pay the principal of, and premium, if any, and interest on,
the Debt Securities of any series in a Foreign Currency or Dollars (the
"Designated Currency") as may be specified pursuant to Section 2.03 is of the
essence and agrees that, to the fullest extent possible under applicable law,
judgments in respect of Debt Securities of such series shall be given in the
Designated Currency; (b) the obligation of the Issuers to make payments in the
Designated Currency of the principal of, and premium, if any, and interest on,
such Debt Securities shall, notwithstanding any payment in any other Currency
(whether pursuant to a judgment or otherwise), be discharged only to the extent
of the amount in the Designated Currency that the Holder receiving such payment
may, in accordance with normal banking procedures, purchase with the sum paid in
such other Currency (after any premium and cost exchange) on the business day in
the country of issue of the Designated Currency or in the international banking
community (in the case of a composite currency) immediately following the day on
which such Holder receives such payment; (c) if the amount in the Designated
Currency that may be so purchased for any reason falls short of the amount
originally due, the Issuers shall pay such additional amounts as may be
necessary to compensate for such shortfall; and (d) any obligation of the
Issuers not discharged by such payment shall be due as a separate and
independent obligation and, until discharged as provided herein, shall continue
in full force and effect.

                  SECTION 2.19. CUSIP Numbers. The Issuers in issuing the Debt
                                -------------
Securities may use "CUSIP" numbers (if then generally in use), and, if so, the
Trustee shall use "CUSIP" numbers in notices of redemption as a convenience to
Holders; provided that any such notice may state that no representation is made
         --------
as to the correctness of such numbers either as printed on the Debt Securities
or as contained in any notice of a redemption and that reliance may be placed
only on the other identification numbers printed on the Debt Securities, and any
such redemption shall not be affected by any defect in or omission of such
numbers. The Issuers will promptly notify the Trustee of any change in the
"CUSIP" numbers.

                                  ARTICLE III

                         Redemption of Debt Securities
                         -----------------------------

                  SECTION 3.01. Applicability of Article. The provisions of this
                                ------------------------
Article shall be applicable to the Debt Securities of any series which are
redeemable before their Stated Maturity except as otherwise specified as
contemplated by Section 2.03 for Debt Securities of such series.

                                       22
<PAGE>

                  SECTION 3.02. Notice of Redemption; Selection of Debt
                                ---------------------------------------
Securities. In case the Issuers shall desire to exercise the right to redeem all
----------
or, as the case may be, any part of the Debt Securities of any series in
accordance with their terms, a Board Resolution of each Issuer or a supplemental
Indenture, the Issuers shall fix a date for redemption and shall give notice of
such redemption at least 30 and not more than 60 days prior to the date fixed
for redemption to the Holders of Debt Securities of such series so to be
redeemed as a whole or in part, in the manner provided in Section 12.03. The
notice may not be conditional. The notice if given in the manner herein provided
shall be conclusively presumed to have been duly given, whether or not the
Holder receives such notice. In any case, failure to give such notice or any
defect in the notice to the Holder of any Debt Security of a series designated
for redemption as a whole or in part shall not affect the validity of the
proceedings for the redemption of any other Debt Security of such series.

                  Each such notice of redemption shall specify the amount of
Debt Securities of any series to be redeemed, the date fixed for redemption, the
calculation of the redemption price at which Debt Securities of such series are
to be redeemed (but not the redemption price itself if it is not then
determinable), the Place or Places of Payment that payment will be made upon
presentation and surrender of such Debt Securities, that any interest accrued to
the date fixed for redemption will be paid as specified in said notice, that the
redemption is for a sinking fund payment (if applicable), that on and after said
date any interest thereon or on the portions thereof to be redeemed will cease
to accrue, that in the case of Original Issue Discount Securities original issue
discount accrued after the date fixed for redemption will cease to accrue, the
terms of the Debt Securities of that series pursuant to which the Debt
Securities of that series are being redeemed and that no representation is made
as to the correctness or accuracy of the CUSIP number, if any, listed in such
notice or printed on the Debt Securities of that series. If less than all the
Debt Securities of a series are to be redeemed the notice of redemption shall
specify the CUSIP numbers of the Debt Securities of that series to be redeemed.
In case any Debt Security of a series is to be redeemed in part only, the notice
of redemption shall state the portion of the principal amount thereof to be
redeemed and shall state that on and after the date fixed for redemption, upon
surrender of such Debt Security, a new Debt Security or Debt Securities of that
series will be issued in principal amount equal to the unredeemed portion
thereof.

                  At least 60 days before the redemption date, unless the
Trustee consents to a shorter period, the Issuers shall give written notice to
the Trustee of the redemption date, the principal amount of Debt Securities to
be redeemed and the series and terms of the Debt Securities pursuant to which
such redemption will occur. Such notice shall be accompanied by an Officers'
Certificate and an Opinion of Counsel to the effect that such redemption will
comply with the conditions herein. If fewer than all the Debt Securities of a
series are to be redeemed, the record date relating to such redemption shall be
selected by the Issuers and given to the Trustee, which record date shall be not
less than 15 days after the date of notice to the Trustee.

                  No later than 11:00 A.M., New York City time, on the
redemption date for any Debt Securities, the Issuers shall deposit with the
Trustee or with a paying agent (or, if the Partnership or PAA Finance is acting
as its own paying agent, segregate and hold in trust) an amount of money in the
Currency in which such Debt Securities are denominated (except as

                                       23
<PAGE>

provided pursuant to Section 2.03) sufficient to pay the redemption price of
such Debt Securities or any portions thereof that are to be redeemed on that
date.

                  If less than all the Debt Securities of like tenor and terms
of a series are to be redeemed (other than pursuant to mandatory sinking fund
redemptions), the Trustee shall select the Debt Securities of that series or
portions thereof (in multiples of $1,000) to be redeemed (i) if such Debt
Securities are listed on an exchange, in compliance with the requirements of the
principal national securities exchange on which such Debt Securities are listed,
or (ii) if such Debt Securities are not listed on an exchange or such exchange
has no selection requirements, on a pro rata basis, by lot or by such other
method as in its sole discretion the Trustee shall deem appropriate and fair. In
any case where more than one Debt Security of such series is registered in the
same name, the Trustee in its discretion may treat the aggregate principal
amount so registered as if it were represented by one Debt Security of such
series. The Trustee shall promptly notify the Issuers in writing of the Debt
Securities selected for redemption and, in the case of any Debt Securities
selected for partial redemption, the principal amount thereof to be redeemed. If
any Debt Security called for redemption shall not be so paid upon surrender
thereof on such redemption date, the principal, premium, if any, and interest
shall bear interest until paid from the redemption date at the rate borne by the
Debt Securities of that series. If less than all the Debt Securities of unlike
tenor and terms of a series are to be redeemed, the particular Debt Securities
to be redeemed shall be selected by the Issuers. Provisions of the Indenture
that apply to Debt Securities called for redemption also apply to portions of
Debt Securities called for redemption.

                  SECTION 3.03. Payment of Debt Securities Called for
                                -------------------------------------
Redemption. If notice of redemption has been given as provided in Section 3.02,
----------
the Debt Securities or portions of Debt Securities of the series with respect to
which such notice has been given shall become due and payable on the date and at
the Place or Places of Payment stated in such notice at the applicable
redemption price, together with any interest accrued to the date fixed for
redemption, and on and after said date (unless the Issuers shall default in the
payment of such Debt Securities at the applicable redemption price, together
with any interest accrued to said date) any interest on the Debt Securities or
portions of Debt Securities of any series so called for redemption shall cease
to accrue and any original issue discount in the case of Original Issue Discount
Securities shall cease to accrue. On presentation and surrender of such Debt
Securities at the Place or Places of Payment in said notice specified, the said
Debt Securities or the specified portions thereof shall be paid and redeemed by
the Issuers at the applicable redemption price, together with any interest
accrued thereon to the date fixed for redemption.

                  Any Debt Security that is to be redeemed only in part shall be
surrendered at the Corporate Trust Office of the Trustee or such other office or
agency of the Issuers as is specified pursuant to Section 2.03, if the Issuers,
the Registrar or the Trustee so requires, due endorsement by, or a written
instrument of transfer in form satisfactory to the Issuers, the Registrar and
the Trustee duly executed by, the Holder thereof or his attorney duly authorized
in writing, and the Issuers shall execute, and the Trustee shall authenticate
and deliver to the Holder of such Debt Security without service charge, a new
Debt Security or Debt Securities of the same series, of like tenor and form, of
any authorized denomination as requested by such Holder in aggregate principal
amount equal to and in exchange for the unredeemed portion of the principal of
the Debt Security so surrendered; except that if a Global Security is so
surrendered, the Issuers shall

                                       24
<PAGE>

execute, and the Trustee shall authenticate and deliver to the Depositary for
such Global Security, without service charge, a new Global Security in a
denomination equal to and in exchange for the unredeemed portion of the
principal of the Global Security so surrendered. In the case of a Debt Security
providing appropriate space for such notation, at the option of the Holder
thereof, the Trustee, in lieu of delivering a new Debt Security or Debt
Securities as aforesaid, may make a notation on such Debt Security of the
payment of the redeemed portion thereof.

                  SECTION 3.04. Mandatory and Optional Sinking Funds. The
                                ------------------------------------
minimum amount of any sinking fund payment provided for by the terms of Debt
Securities of any series, a Board Resolution or a supplemental Indenture is
herein referred to as a "mandatory sinking fund payment", and any payment in
excess of such minimum amount provided for by the terms of Debt Securities of
any series, a Board Resolution or a supplemental Indenture is herein referred to
as an "optional sinking fund payment."

                  In lieu of making all or any part of any mandatory sinking
fund payment with respect to any Debt Securities of a series in cash, the
Issuers may at their option (a) deliver to the Trustee Debt Securities of that
series theretofore purchased or otherwise acquired by the Issuers or (b) receive
credit for the principal amount of Debt Securities of that series which have
been redeemed either at the election of the Issuers pursuant to the terms of
such Debt Securities or through the application of permitted optional sinking
fund payments pursuant to the terms of such Debt Securities, resolution or
supplemental Indenture; provided, that such Debt Securities have not been
                        --------
previously so credited. Such Debt Securities shall be received and credited for
such purpose by the Trustee at the redemption price specified in such Debt
Securities, the applicable Board Resolution or supplemental Indenture for
redemption through operation of the sinking fund and the amount of such
mandatory sinking fund payment shall be reduced accordingly.

                  SECTION 3.05. Redemption of Debt Securities for Sinking Fund.
                                ----------------------------------------------
Not less than 60 days prior to each sinking fund payment date for any series of
Debt Securities, the Issuers will deliver to the Trustee an Officers'
Certificate specifying the amount of the next ensuing sinking fund payment for
that series pursuant to the terms of that series, any Board Resolution or
supplemental Indenture, the portion thereof, if any, which is to be satisfied by
payment of cash in the Currency in which the Debt Securities of such series are
denominated (except as provided pursuant to Section 2.03) and the portion
thereof, if any, which is to be satisfied by delivering and crediting Debt
Securities of that series pursuant to this Section 3.05 (which Debt Securities,
if not previously redeemed, will accompany such certificate) and whether the
Issuers intend to exercise their right to make any permitted optional sinking
fund payment with respect to such series. Such certificate shall also state that
no Event of Default has occurred and is continuing with respect to such series.
Such certificate shall be irrevocable and upon its delivery the Issuers shall be
obligated to make the cash payment or payments therein referred to, if any, on
or before the next succeeding sinking fund payment date. Failure of the Issuers
to deliver such certificate (or to deliver the Debt Securities specified in this
paragraph) shall not constitute a Default, but such failure shall require that
the sinking fund payment due on the next succeeding sinking fund payment date
for that series shall be paid entirely in cash and shall be sufficient to redeem
the principal amount of such Debt Securities subject to a mandatory sinking fund
payment without

                                       25
<PAGE>

the option to deliver or credit Debt Securities as provided in this Section 3.05
and without the right to make any optional sinking fund payment, if any, with
respect to such series.

                  Any sinking fund payment or payments (mandatory or optional)
made in cash plus any unused balance of any preceding sinking fund payments made
in cash which shall equal or exceed $100,000 (or a lesser sum if the Issuers
shall so request) with respect to the Debt Securities of any particular series
shall be applied by the Trustee on the sinking fund payment date on which such
payment is made (or, if such payment is made before a sinking fund payment date,
on the sinking fund payment date following the date of such payment) to the
redemption of such Debt Securities at the redemption price specified in such
Debt Securities, the applicable Board Resolution or supplemental Indenture for
operation of the sinking fund together with any accrued interest to the date
fixed for redemption. Any sinking fund moneys not so applied or allocated by the
Trustee to the redemption of Debt Securities shall be added to the next cash
sinking fund payment received by the Trustee for such series and, together with
such payment, shall be applied in accordance with the provisions of this Section
3.05. Any and all sinking fund moneys with respect to the Debt Securities of any
particular series held by the Trustee on the last sinking fund payment date with
respect to Debt Securities of such series and not held for the payment or
redemption of particular Debt Securities shall be applied by the Trustee,
together with other moneys, if necessary, to be deposited sufficient for the
purpose, to the payment of the principal of the Debt Securities of that series
at its Stated Maturity.

                  The Trustee shall select the Debt Securities to be redeemed
upon such sinking fund payment date in the manner specified in the last
paragraph of Section 3.02 and the Issuers shall cause notice of the redemption
thereof to be given in the manner provided in Section 3.02 except that the
notice of redemption shall also state that the Debt Securities are being
redeemed by operation of the sinking fund. Such notice having been duly given,
the redemption of such Debt Securities shall be made upon the terms and in the
manner stated in Section 3.03.

                  At least one business day before each sinking fund payment
date, the Issuers shall pay to the Trustee (or, if the Partnership or PAA
Finance is acting as its own paying agent, the Partnership or PAA Finance shall
segregate and hold in trust) in cash a sum in the Currency in which the Debt
Securities of such series are denominated (except as provided pursuant to
Section 2.03) equal to any interest accrued to the date fixed for redemption of
Debt Securities or portions thereof to be redeemed on such sinking fund payment
date pursuant to this Section 3.05.

                  The Trustee shall not redeem any Debt Securities of a series
with sinking fund moneys or mail any notice of redemption of such Debt
Securities by operation of the sinking fund for such series during the
continuance of a Default in payment of interest on such Debt Securities or of
any Event of Default (other than an Event of Default occurring as a consequence
of this paragraph) with respect to such Debt Securities, except that if the
notice of redemption of any such Debt Securities shall theretofore have been
mailed in accordance with the provisions hereof, the Trustee shall redeem such
Debt Securities if cash sufficient for that purpose shall be deposited with the
Trustee for that purpose in accordance with the terms of this Article III.
Except as aforesaid, any moneys in the sinking fund for such series at the time
when any such Default or Event of Default shall occur and any moneys thereafter
paid into such sinking fund shall, during the continuance of such Default or
Event of Default, be held as security for the payment of such Debt Securities;
provided, however, that in case such Default or Event of
--------  -------

                                       26
<PAGE>

Default shall have been cured or waived as provided herein, such moneys shall
thereafter be applied on the next sinking fund payment date for such Debt
Securities on which such moneys may be applied pursuant to the provisions of
this Section 3.05.

                                  ARTICLE IV

                      Particular Covenants of the Issuers
                      -----------------------------------

                  SECTION 4.01. Payment of Principal of, and Premium, If Any,
                                ---------------------------------------------
and Interest on, Debt Securities. The Issuers, for the benefit of each series of
--------------------------------
Debt Securities, will duly and punctually pay or cause to be paid the principal
of, and premium, if any, and interest on, each of the Debt Securities at the
place, at the respective times and in the manner provided herein and in the Debt
Securities. Each installment of interest on the Debt Securities may at the
Issuers' option be paid by mailing checks for such interest payable to the
Person entitled thereto to the address of such Person as it appears on the Debt
Security Register maintained pursuant to Section 2.07(a).

                  Principal, premium and interest in respect of Debt Securities
of any series shall be considered paid on the date due if no later than 11:00
A.M., New York City time, on such date the Trustee or any paying agent holds in
accordance with the Indenture money sufficient to pay in the Currency in which
the Debt Securities of such series are denominated (except as provided pursuant
to Section 2.03) all principal, premium and interest then due.

                  The Issuers shall pay interest on overdue principal at the
rate specified therefor in the Debt Securities and they shall pay interest on
overdue installments of interest at the same rate to the extent lawful.

                  SECTION 4.02. Maintenance of Offices or Agencies for
                                --------------------------------------
Registration of Transfer, Exchange and Payment of Debt Securities. The Issuers
-----------------------------------------------------------------
will maintain in each Place of Payment for any series of Debt Securities, an
office or agency where Debt Securities of such series may be presented or
surrendered for payment, where Debt Securities of such series may be surrendered
for transfer or exchange and where notices and demands to or upon the Issuers in
respect of the Debt Securities of such series and the Indenture may be served.
The Issuers will give prompt written notice to the Trustee of the location, and
any change in the location, of such office or agency. If at any time the Issuers
shall fail to maintain any such required office or agency or shall fail to
furnish the Trustee with the address thereof, such presentations, surrenders,
notices and demands may be made or served at the Corporate Trust Office of the
Trustee, and the Issuers hereby appoint the Trustee as its agent to receive all
presentations, surrenders, notices and demands.

                  The Issuers may also from time to time designate different or
additional offices or agencies to be maintained for such purposes (in or outside
of such Place of Payment), and may from time to time rescind any such
designation; provided, however, that no such designation or rescission shall in
any manner relieve the Issuers of their obligations described in the preceding
paragraph. The Issuers will give prompt written notice to the Trustee of any
such additional designation or rescission of designation and any change in the
location of any such different or additional office or agency.

                                       27
<PAGE>

                  SECTION 4.03. Appointment to Fill a Vacancy in the Office of
                                ----------------------------------------------
Trustee. The Issuers, whenever necessary to avoid or fill a vacancy in the
-------
office of Trustee, will appoint, in the manner provided in Section 7.08, a
Trustee, so that there shall at all times be a Trustee hereunder with respect to
each series of Debt Securities.

                  SECTION 4.04. Duties of Paying Agents, etc. (a) The Issuers
                                ----------------------------
shall cause each paying agent, if any, other than the Trustee, to execute and
deliver to the Trustee an instrument in which such agent shall agree with the
Trustee, subject to the provisions of this Section 4.04,

                  (i)    that it will hold all sums held by it as such agent for
         the payment of the principal of, and premium, if any, or interest on,
         the Debt Securities of any series (whether such sums have been paid to
         it by the Issuers or by any other obligor on the Debt Securities of
         such series) in trust for the benefit of the Holders of the Debt
         Securities of such series;

                  (ii)   that it will give the Trustee notice of any failure by
         the Issuers (or by any other obligor on the Debt Securities of such
         series) to make any payment of the principal of and premium, if any, or
         interest on, the Debt Securities of such series when the same shall be
         due and payable; and

                  (iii)  that it will at any time during the continuance of an
         Event of Default, upon the written request of the Trustee, forthwith
         pay to the Trustee all sums so held by it as such agent.

                  (b)    If either of the Issuers or any of their respective
Subsidiaries shall act as its own paying agent, it will, on or before 11:00
A.M., New York City time, on each due date of the principal of, and premium, if
any, or interest on, the Debt Securities if any, of any series, set aside,
segregate and hold in trust for the benefit of the Holders of the Debt
Securities of such series a sum sufficient to pay such principal, premium, if
any, or interest so becoming due. The Issuers will promptly notify the Trustee
of any failure by the Issuers or its Subsidiaries to take such action or the
failure by any other obligor on such Debt Securities to make any payment of the
principal of, and premium, if any, or interest on, such Debt Securities when the
same shall be due and payable.

                  (c)    Anything in this Section 4.04 to the contrary
notwithstanding, either of the Issuers may, at any time, for the purpose of
obtaining a satisfaction and discharge of the Indenture, or for any other
reason, pay or cause to be paid to the Trustee all sums held in trust by it or
any paying agent, as required by this Section 4.04, such sums to be held by the
Trustee upon the same terms as those upon which such sums were held by the
Issuers or such paying agent.

                  (d)    Whenever the Issuers shall have one or more paying
agents with respect to any series of Debt Securities, they will, prior to 11:00
A.M., New York City time, on each due date of the principal of, and premium, if
any, or interest on, any Debt Securities of such series, deposit with any such
paying agent a sum sufficient to pay the principal, premium or interest so
becoming due, such sum to be held in trust for the benefit of the Persons
entitled thereto, and (unless any such paying agent is the Trustee) the Issuers
will promptly notify the Trustee of their action or failure so to act.

                                       28
<PAGE>

                  (e)  Anything in this Section 4.04 to the contrary
notwithstanding, the agreement to hold sums in trust as provided in this Section
4.04 is subject to the provisions of Section 11.02.

                  (f)  Unless and until otherwise determined by the Issuers in
Board Resolutions or pursuant to a supplemental Indenture, the Trustee will act
as paying agent under the Indenture. The Issuers may designate a substitute
paying agent without prior notice to the Holders of Debt Securities.

                  SECTION 4.05. Statement by Officers as to Default. The Issuers
                                -----------------------------------
will deliver to the Trustee, on or before a date not more than four months after
the end of each fiscal year of the Issuers (currently ending on December 31 of
each year) ending after the date hereof, an Officers' Certificate stating, as to
each officer signing such certificate, one of whom shall be the principal
executive, financial or accounting officer of each Issuer, that (i) in the
course of his performance of his duties as an officer of the Managing General
Partner or PAA Finance, as applicable, he would normally have knowledge of any
Default, (ii) whether or not to the best of his knowledge any Default occurred
during such year and (iii) if to the best of his knowledge the Partnership or
PAA Finance, as applicable, is in Default, specifying all such Defaults and what
action the Partnership or PAA Finance, as applicable, is taking or proposes to
take with respect thereto.

                  SECTION 4.06. Further Instruments and Acts. The Issuers will,
                                ----------------------------
upon request of the Trustee, execute and deliver such further instruments and do
such further acts as may reasonably be necessary or proper to carry out more
effectually the purposes of the Indenture.

                  SECTION 4.07. Corporate, Partnership or Limited Liability
                                -------------------------------------------
Company Existence. Subject to Article X, the Issuers shall do or cause to be
-----------------
done all things necessary to preserve and keep in full force and effect the
corporate, partnership or limited liability company existence and related rights
and franchises (charges and statutory) of the Partnership and each of its
Subsidiaries; provided, however, that the Partnership shall not be required to
              --------  -------
preserve any such right or franchise for the corporate, partnership or limited
liability company existence of any such Subsidiary if the management of the
Managing General Partner shall determine that the preservation thereof is no
longer desirable in the conduct of the business of the Partnership and its
Subsidiaries as a whole and that the loss thereof would not reasonably be
expected to have a material adverse effect on the ability of the Issuers or any
obligor on the Debt Securities of any series to perform their obligations
hereunder; and provided, further, however, that the foregoing shall not prohibit
               --------  -------  -------
a sale, transfer or conveyance of a Subsidiary of the Partnership or any of its
assets in compliance with the terms of the Indenture.

                  SECTION 4.08. Maintenance of Properties. The Partnership shall
                                -------------------------
cause all material properties owned by the Partnership or any of its
Subsidiaries or used or held for use in the conduct of its business or the
business of any of its Subsidiaries to be maintained and kept in good condition,
repair and working order (ordinary wear and tear excepted) and supplied with all
necessary equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the reasonable
judgment of the Partnership may be consistent with sound business practice and
necessary so that the business carried on in connection therewith may be
properly conducted at all times; provided, however, that nothing in this Section
                                 --------  -------
shall prevent the Partnership from discontinuing the maintenance of any of such

                                       29
<PAGE>

properties if such discontinuance is, in the reasonable judgment of the
management of the Managing General Partner, desirable in the conduct of its
business or the business of any of its Subsidiaries and not reasonably expected
to have a material adverse effect on the ability of the Issuers or any obligor
on the Debt Securities of any series to perform their obligations hereunder.

                  SECTION 4.09. Payment of Taxes and Other Claims. The
                                ---------------------------------
Partnership shall pay or discharge or cause to be paid or discharged, on or
before the date the same shall become due and payable, (a) all taxes,
assessments and governmental charges levied or imposed upon the Partnership or
any of its Subsidiaries or otherwise assessed or upon the income, profits or
property of the Partnership or any of its Subsidiaries if failure to pay or
discharge the same could reasonably be expected to have a material adverse
effect on the ability of the Issuers or any obligor on the Debt Securities of
any series to perform their obligations hereunder and (b) all lawful claims for
labor, materials and supplies, which, if unpaid, would by law become a Lien upon
the property of the Partnership or any of its Subsidiaries, except for any Lien
permitted to be incurred under the terms of the Indenture, if failure to pay or
discharge the same could reasonably be expected to have a material adverse
effect on the ability of the Issuers or any obligor on the Debt Securities of
any series to perform their obligations hereunder; provided, however, that the
                                                   --------  -------
Partnership shall not be required to pay or discharge or cause to be paid or
discharged any such tax, assessment, charge or claim whose amount, applicability
or validity is being contested in good faith by appropriate proceedings properly
instituted and diligently conducted and in respect of which appropriate reserves
(in the good faith judgment of management of the Managing General Partner) are
being maintained in accordance with GAAP.

                  SECTION 4.10. Calculation of Original Issue Discount. The
                                --------------------------------------
Issuers shall file with the Trustee promptly at the end of each calendar year
(i) a written notice specifying the amount of original issue discount (including
daily rates and accrual periods) accrued on Outstanding Original Issue Discount
Debt Securities as of the end of such year and (ii) such other specific
information relating to such original issue discount as may then be relevant
under the Code.

                  SECTION 4.11. Stay, Extension and Usury Laws. Each of the
                                ------------------------------
Issuers covenants (to the extent that it may lawfully do so) that it shall not
at any time insist upon, plead or in any manner whatsoever claim or take the
benefit or advantage of, any stay, extension or usury law wherever enacted, now
or at any time hereafter in force, that may affect the covenants or the
performance of the Indenture; and each of the Issuers hereby expressly waives
all benefit or advantage of any such law, and covenants that it shall not, by
resort to any such law, hinder, delay or impede the execution of any power
herein granted to the Trustee, but shall suffer and permit the execution of
every such power as though no such law has been enacted.

                                   ARTICLE V

                          Holders' Lists and Reports
                          --------------------------
                        by the Issuers and the Trustee
                        ------------------------------

                  SECTION 5.01. Issuers to Furnish Trustee Information as to
                                --------------------------------------------
Names and Addresses of Holders; Preservation of Information. The Issuers
------------------------------  ---------------------------
covenant and agree that they

                                       30
<PAGE>

will furnish or cause to be furnished to the Trustee with respect to the
Registered Securities of each series:

                  (a)  not more than 15 days after each record date with respect
         to the payment of interest, if any, a list, in such form as the Trustee
         may reasonably require, of the names and addresses of the Registered
         Holders as of such record date, and

                  (b)  at such other times as the Trustee may request in
         writing, within 30 days after the receipt by the Issuers of any such
         request, a list as of a date not more than 15 days prior to the time
         such list is furnished;

provided, however, that so long as the Trustee shall be the Registrar, such
--------  -------
lists shall not be required to be furnished.

                  The Trustee shall preserve, in as current a form as is
reasonably practicable, all information as to the names and addresses of the
Holders (1) contained in the most recent list furnished to it as provided in
this Section 5.01 or (2) received by it in the capacity of paying agent or
Registrar (if so acting) hereunder.

                  The Trustee may destroy any list furnished to it as provided
in this Section 5.01 upon receipt of a new list so furnished.

                  SECTION 5.02. Communications to Holders; Meetings of Holders.
                                ----------------------------------------------
(a) Holders may communicate pursuant to Section 312(b) of the Trust Indenture
Act with other Holders with respect to their rights under the Indenture or the
Debt Securities. The Issuers, the Trustee, the Registrar and anyone else shall
have the protection of Section 312(c) of the Trust Indenture Act.

                  (b)  A meeting of the Holders of Debt Securities of any or all
series may be called at any time and from time to time pursuant to this Section
5.02 to make, give or take any request, demand, authorization, direction,
notice, consent, waiver or other action provided herein to be made, given or
taken by Holders of Debt Securities of such series.

                  (c)  The Trustee may at any time call a meeting of Holders of
Debt Securities of any series for any purpose specified herein to be held at
such time and at such place in Houston, Texas, in The Borough of Manhattan, The
City of New York or in any other location, as the Trustee shall determine.
Notice of every meeting of Holders of any series, setting forth the time and the
place of such meeting and in general terms the action proposed to be taken at
such meeting, shall be given not less than 20 nor more than 180 days prior to
the date fixed for the meeting.

                  (d)  In case at any time the Issuers, pursuant to Board
Resolutions, or the Holders of at least 10% in aggregate principal amount of the
outstanding Debt Securities of any series, shall have requested the Trustee for
any such series to call a meeting of the Holders of Debt Securities of such
series for any purpose specified herein, by written request setting forth in
reasonable detail the action proposed to be taken at the meeting, and the
Trustee shall not have made the first publication of the notice of such meeting
within 30 days after receipt of such request or shall not thereafter proceed to
cause the meeting to be held as provided herein, then

                                       31
<PAGE>

the Issuers or the Holders of such series in the amount specified above, as the
case may be, may determine the time and the place in Houston, Texas, in The
Borough of Manhattan, The City of New York, or in any other location, for such
meeting and may call such meeting for such purposes by giving notice thereof as
provided in paragraph (c) of this Section 5.02.

                  SECTION 5.03. Reports by Issuers. (a) Notwithstanding that the
                                ------------------
Partnership may not be required to remain subject to the reporting requirements
of Section 13 or 15(d) of the Exchange Act, the Partnership shall file with the
Commission and provide to the Trustee and the Holders of Debt Securities the
annual reports and the information, documents and other reports that are
specified in Sections 13 and 15(d) of the Exchange Act, and, with respect to the
annual consolidated financial statements only, a report thereon by the Issuers'
independent auditors; provided, however, that the Partnership shall not be so
                      --------  -------
obligated to file such information, documents and reports with the Commission if
the Commission does not permit such filings. The Issuers shall comply with the
other provisions of Section 314(a) of the Trust Indenture Act.

                  (b)  The Issuers covenant and agree, and any obligor hereunder
shall covenant and agree, to file with the Trustee and the Commission, in
accordance with the rules and regulations prescribed from time to time by said
Commission, such additional information, documents, and reports with respect to
compliance by the Issuers or such obligor, as the case may be, with the
conditions and covenants provided for in the Indenture as may be required from
time to time by such rules and regulations.

                  (c)  Delivery of such reports, information and documents to
the Trustee is for informational purposes only and the Trustee's receipt of such
shall not constitute notice of any information contained therein or determinable
from information contained therein, including the Issuers' compliance with any
of their covenants hereunder (as to which the Trustee is entitled to rely
exclusively on Officers' Certificates).

                  SECTION 5.04. Reports by Trustee. The Trustee shall transmit
                                ------------------
to Holders such reports concerning the Trustee and its actions under the
Indenture as may be required pursuant to the Trust Indenture Act at the time and
in the manner provided pursuant thereto.

                  Reports pursuant to this Section 5.04 shall be transmitted by
         mail:

                  (1)  to all Registered Holders, as the names and addresses of
         such Holders appear in the Debt Security Register; and

                  (2)  except in the cases of reports under Section 313(b)(2) of
         the Trust Indenture Act, to each holder of a Debt Security of any
         series whose name and address appear in the information preserved at
         the time by the Trustee in accordance with Section 5.02.

                  A copy of each report at the time of its mailing to Holders
shall be filed with the Commission and each stock exchange (if any) on which the
Debt Securities of any series are listed. The Issuers agree to notify promptly
the Trustee whenever the Debt Securities of any series become listed on any
stock exchange and of any delisting thereof.

                                       32
<PAGE>

                  SECTION 5.05. Record Dates for Action by Holders. If the
                                ----------------------------------
Issuers shall solicit from the Holders of Debt Securities of any series any
action (including the making of any demand or request, the giving of any
direction, notice, consent or waiver or the taking of any other action), the
Issuers may, at their option, by Board Resolutions, fix in advance a record date
for the determination of Holders of Debt Securities entitled to take such
action, but the Issuers shall have no obligation to do so. Any such record date
shall be fixed at the Issuers' discretion. If such a record date is fixed, such
action may be sought or given before or after the record date, but only the
Holders of Debt Securities of record at the close of business on such record
date shall be deemed to be Holders of Debt Securities for the purpose of
determining whether Holders of the requisite proportion of Debt Securities of
such series Outstanding have authorized or agreed or consented to such action,
and for that purpose the Debt Securities of such series Outstanding shall be
computed as of such record date.

                                  ARTICLE VI

            Remedies of the Trustee and Holders in Event of Default
            -------------------------------------------------------

                  SECTION 6.01. Events of Default. If any one or more of the
                                -----------------
following shall have occurred and be continuing with respect to Debt Securities
of any series (each of the following, an "Event of Default"):

                  (a)  the Issuers Default for a period of 60 days in the
         payment when due of interest on any Debt Securities of that series; or

                  (b)  the Issuers default in the payment when due of principal
         of or premium, if any, on any Debt Securities of that series at
         maturity, upon redemption or otherwise; or

                  (c)  default in the payment of any sinking fund payment with
         respect to any Debt Securities of that series as and when the same
         shall become due and payable; or

                  (d)  failure on the part of the Issuers to comply with Article
         X; or

                  (e)  failure by the Issuers for 30 days after notice to comply
         to duly observe or perform any other of the covenants or agreements on
         the part of the Issuers in the Debt Securities of that series in any
         Board Resolution authorizing the issuance of that series of Debt
         Securities, in the Indenture with respect to such series or in any
         supplemental Indenture with respect to such series (other than a
         covenant a default in the performance of which is elsewhere in this
         Section 6.01 specifically dealt with); or

                  (f)  pursuant to or within the meaning of Bankruptcy Law, an
         Issuer commences a voluntary case, consents to the entry of an order
         for relief against it in an involuntary case, consents to the
         appointment of a custodian of it or for all or substantially all of its
         property, makes a general assignment for the benefit of its creditors,
         or generally is not paying its debts as they become due; or

                  (g)  (i) a court of competent jurisdiction enters an order or
         decree under any Bankruptcy Law that is for relief against an Issuer in
         an involuntary case, appoints a

                                       33
<PAGE>

         custodian of an Issuer, or orders the liquidation of an Issuer and (ii)
         such order or decree remains unstayed and in effect for 60 consecutive
         days; or

                  (h)  any other Event of Default provided under the terms of
         the Debt Securities of that series;

then and in each and every case that an Event of Default with respect to Debt
Securities of that series at the time outstanding occurs and is continuing,
either the Trustee or the Holders of at least 25% in aggregate principal amount
of the Debt Securities of that series, may declare the principal of (or, if the
Debt Securities of that series are Original Issue Discount Debt Securities, such
portion of the principal amount as may be specified in the terms of that series)
and interest on all the Debt Securities of that series to be due and payable
immediately.

                  The Holders of a majority in principal amount of the Debt
Securities of a particular series by notice to the Trustee may rescind an
acceleration and its consequences if the rescission would not conflict with any
judgment or decree already rendered and if all existing Events of Default have
been cured or waived except nonpayment of principal or interest that has become
due solely because of acceleration. Upon any such rescission, the parties hereto
shall be restored respectively to their several positions and rights hereunder,
and all rights, remedies and powers of the parties hereto shall continue as
though no proceeding had been taken.

                  In case the Trustee or any Holder shall have proceeded to
enforce any right under the Indenture and such proceedings shall have been
discontinued or abandoned because of such rescission or annulment or for any
other reason or shall have been determined adversely to the Trustee or such
Holder, then and in every such case the parties hereto shall be restored
respectively to their several positions and rights hereunder, and all rights,
remedies and powers of the parties hereto shall continue as though no such
proceeding had been taken.

                  The foregoing Events of Default shall constitute Events of
Default whatever the reason for any such Event of Default and whether it is
voluntary or involuntary or is effected by operation of law or pursuant to any
judgment, decree or order of any court or any order, rule or regulation of any
administrative or governmental body.

                  The Issuers shall deliver to the Trustee, within 30 days after
the occurrence thereof, written notice in the form of an Officers' Certificate
of any event which with the giving of notice and the lapse of time would become
an Event of Default under clause (c), (d), (e), (f), (g) or (h), its status and
what action the Issuers are taking or propose to take with respect thereto.

                  SECTION 6.02. Collection of Indebtedness by Trustee, etc. If
                                ------------------------------------------
an Event of Default occurs and is continuing, the Trustee, in its own name and
as trustee of an express trust, shall be entitled and empowered to institute any
action or proceedings at law or in equity for the collection of the sums so due
and unpaid or enforce the performance of any provision of the Debt Securities of
the affected series or the Indenture, and may prosecute any such action or
proceedings to judgment or final decree, and may enforce any such judgment or
final decree against the Issuers or any other obligor upon the Debt Securities
of such series (and collect in the manner provided by law out of the property of
the Issuers or any other obligor upon the Debt Securities of such series
wherever situated the moneys adjudged or decreed to be payable).

                                       34
<PAGE>

                  In case there shall be pending proceedings for the bankruptcy
or for the reorganization of either of the Issuers or any other obligor upon the
Debt Securities of any series under Title 11 of the United States Code or any
other Federal or State bankruptcy, insolvency or similar law, or in case a
receiver, trustee or other similar official shall have been appointed for its
property, or in case of any other similar judicial proceedings relative to
either of the Issuers or any other obligor upon the Debt Securities of any
series, its creditors or its property, the Trustee, irrespective of whether the
principal of Debt Securities of any series shall then be due and payable as
therein expressed or by declaration or otherwise and irrespective of whether the
Trustee shall have made any demand pursuant to the provisions of this Section
6.02, shall be entitled and empowered, by intervention in such proceedings or
otherwise, to file and prove a claim or claims for the whole amount of
principal, premium, if any, and interest (or, if the Debt Securities of such
series are Original Issue Discount Debt Securities, such portion of the
principal amount as may be specified in the terms of such series) owing and
unpaid in respect of the Debt Securities of such series, and to file such other
papers or documents as may be necessary or advisable in order to have the claims
of the Trustee (including any claim for reasonable compensation to the Trustee,
its agents, attorneys and counsel, and for reimbursement of all expenses and
liabilities incurred, and all advances made, by the Trustee except as a result
of its negligence or bad faith) and of the Holders thereof allowed in any such
judicial proceedings relative to either of the Issuers, or any other obligor
upon the Debt Securities of such series, its creditors or its property, and to
collect and receive any moneys or other property payable or deliverable on any
such claims, and to distribute all amounts received with respect to the claims
of such Holders and of the Trustee on their behalf, and any receiver, assignee
or trustee in bankruptcy or reorganization is hereby authorized by each of such
Holders to make payments to the Trustee, and, in the event that the Trustee
shall consent to the making of payments directly to such Holders, to pay to the
Trustee such amount as shall be sufficient to cover reasonable compensation to
the Trustee, its agents, attorneys and counsel, and all other reasonable
expenses and liabilities incurred, and all advances made, by the Trustee except
as a result of its negligence or bad faith.

                  All rights of action and of asserting claims under the
Indenture, or under any of the Debt Securities, of any series, may be enforced
by the Trustee without the possession of any such Debt Securities or the
production thereof in any trial or other proceedings relative thereto, and any
such action or proceedings instituted by the Trustee shall be brought in its own
name as trustee of an express trust, and any recovery of judgment (except for
any amounts payable to the Trustee pursuant to Section 7.06) shall be for the
ratable benefit of the Holders of all the Debt Securities in respect of which
such action was taken.

                  In case of an Event of Default hereunder the Trustee may in
its discretion proceed to protect and enforce the rights vested in it by the
Indenture by such appropriate judicial proceedings as the Trustee shall deem
necessary to protect and enforce any of such rights, either at law or in equity
or in bankruptcy or otherwise, whether for the specific enforcement of any
covenant or agreement contained in the Indenture or in aid of the exercise of
any power granted in the Indenture, or to enforce any other legal or equitable
right vested in the Trustee by the Indenture or by law.

                  SECTION 6.03. Application of Moneys Collected by Trustee. Any
                                ------------------------------------------
moneys or other property collected by the Trustee pursuant to Section 6.02 with
respect to Debt Securities

                                       35
<PAGE>

of any series shall be applied, after giving effect to the provisions of Article
XIII, in the order following, at the date or dates fixed by the Trustee for the
distribution of such moneys or other property, upon presentation of the several
Debt Securities of such series in respect of which moneys or other property have
been collected, and the notation thereon of the payment, if only partially paid,
and upon surrender thereof if fully paid:

                  First:  To the payment of all money due the Trustee pursuant
                  -----
         to Section 7.06;

                  Second: In case the principal of the Outstanding Debt
                  ------
         Securities in respect of which such moneys have been collected shall
         not have become due, to the payment of interest on the Debt Securities
         of such series in the order of the maturity of the installments of such
         interest, with interest (to the extent that such interest has been
         collected by the Trustee) upon the overdue installments of interest at
         the rate or Yield to Maturity (in the case of Original Issue Discount
         Debt Securities) specified in the Debt Securities of such series, such
         payments to be made ratably to the Persons entitled thereto, without
         discrimination or preference;

                  Third:  In case the principal of the Outstanding Debt
                  -----
         Securities in respect of which such moneys have been collected shall
         have become due, by declaration or otherwise, to the payment of the
         whole amount then owing and unpaid upon the Debt Securities of such
         series for principal and premium, if any, and interest, with interest
         on the overdue principal and premium, if any, and (to the extent that
         such interest has been collected by the Trustee) upon overdue
         installments of interest at the rate or Yield to Maturity (in the case
         of Original Issue Discount Debt Securities) specified in the Debt
         Securities of such series; and, in case such moneys shall be
         insufficient to pay in full the whole amount so due and unpaid upon the
         Debt Securities of such series, then to the payment of such principal
         and premium, if any, and interest, without preference or priority of
         principal and premium, if any, over interest, or of interest over
         principal and premium, if any, or of any installment of interest over
         any other installment of interest, or of any Debt Security of such
         series over any Debt Security of such series, ratably to the aggregate
         of such principal and premium, if any, and interest; and

                  Fourth: The remainder, if any, shall be paid to the Issuers,
                  ------
         their successors or assigns, or as a court of competent jurisdiction
         may direct.

                  The Trustee may fix a record date and payment date for any
payment to Holders pursuant to this Section 6.03. At least 15 days before such
record date, the Issuers shall mail to each Holder and the Trustee a notice that
states the record date, the payment date and amount to be paid.

                  SECTION 6.04. Limitation on Suits by Holders. No Holder of any
                                ------------------------------
Debt Security of any series shall have any right by virtue or by availing of any
provision of the Indenture to institute any action or proceeding at law or in
equity or in bankruptcy or otherwise, upon or under or with respect to the
Indenture, or for the appointment of a receiver or trustee, or for any other
remedy hereunder, unless such Holder previously shall have given to the Trustee
written notice of an Event of Default with respect to Debt Securities of that
same series and of the continuance thereof and unless the Holders of not less
than 25% in aggregate principal

                                       36
<PAGE>

amount of the Outstanding Debt Securities of that series shall have made written
request upon the Trustee to institute such action or proceedings in respect of
such Event of Default in its own name as Trustee hereunder and shall have
offered to the Trustee such reasonable indemnity as it may require against the
costs, expenses and liabilities to be incurred therein or thereby, and the
Trustee, for 60 days after its receipt of such notice, request and offer of
indemnity shall have failed to institute any such action or proceedings and no
direction inconsistent with such written request shall have been given to the
Trustee pursuant to Section 6.06; it being understood and intended, and being
expressly covenanted by the Holder of every Debt Security with every other
Holder and the Trustee, that no one or more Holders shall have any right in any
manner whatever by virtue or by availing of any provision of the Indenture to
affect, disturb or prejudice the rights of any Holders, or to obtain or seek to
obtain priority over or preference to any other such Holder, or to enforce any
right under the Indenture, except in the manner herein provided and for the
equal, ratable and common benefit of all such Holders. For the protection and
enforcement of the provisions of this Section 6.04, each and every Holder and
the Trustee shall be entitled to such relief as can be given either at law or in
equity.

                  Notwithstanding any other provision in the Indenture (but
subject to Article XIII), the right of any Holder of any Debt Security to
receive payment of the principal of, and premium, if any, and (subject to
Section 2.12) interest on, such Debt Security on or after the respective due
dates expressed in such Debt Security, and to institute suit for the enforcement
of any such payment on or after such respective dates, shall not be impaired or
effected without the consent of such Holder.

                  SECTION 6.05. Remedies Cumulative; Delay or Omission in
                                -----------------------------------------
Exercise of Rights Not a Waiver of Default. All powers and remedies given by
------------------------------------------
this Article VI to the Trustee or to the Holders shall, to the extent permitted
by law, be deemed cumulative and not exclusive of any thereof or of any other
powers and remedies available to the Trustee or the Holders, by judicial
proceedings or otherwise, to enforce the performance or observance of the
covenants and agreements contained in the Indenture, and no delay or omission of
the Trustee or of any Holder to exercise any right or power accruing upon any
Default occurring and continuing as aforesaid, shall impair any such right or
power, or shall be construed to be a waiver of any such Default or an
acquiescence therein; and, subject to the provisions of Section 6.04, every
power and remedy given by this Article VI or by law to the Trustee or to the
Holders may be exercised from time to time, and as often as shall be deemed
expedient, by the Trustee or by the Holders.

                  SECTION 6.06. Rights of Holders of Majority in Principal
                                ------------------------------------------
Amount of Debt Securities to Direct Trustee and to Waive Default. The Holders of
----------------------------------------------------------------
a majority in aggregate principal amount of the Debt Securities of any series at
the time Outstanding shall have the right to direct the time, method, and place
of conducting any proceeding for any remedy available to the Trustee, or
exercising any trust or power conferred on the Trustee, with respect to the Debt
Securities of such series; provided, however, that such direction shall not be
                           --------  -------
otherwise than in accordance with law and the provisions of the Indenture, and
that subject to the provisions of Section 7.01, the Trustee shall have the right
to decline to follow any such direction if the Trustee being advised by counsel
shall determine that the action so directed may not lawfully be taken, or if the
Trustee shall by a Responsible Officer or officers determine that the action so
directed would involve it in personal liability or would be prejudicial to
Holders of Debt Securities of such series not taking part in such direction; and
provided further, however, that
-------- -------  -------

                                       37
<PAGE>

nothing in the Indenture contained shall impair the right of the Trustee to take
any action deemed proper by the Trustee and which is not inconsistent with such
direction by such Holders. Prior to the acceleration of the maturity of the Debt
Securities of any series, as provided in Section 6.01, the Holders of a majority
in aggregate principal amount of the Debt Securities of that series at the time
Outstanding by notice to the Trustee may on behalf of the Holders of all the
Debt Securities of that series waive any past Default or Event of Default and
its consequences for that series specified in the terms thereof as contemplated
by Section 2.03, except (i) a Default in the payment of the principal of, and
premium, if any, or interest on, any of the Debt Securities and (ii) a Default
in respect of a provision that under Section 9.02 cannot be amended,
supplemented or waived without the consent of each Holder affected thereby. In
case of any such waiver, such Default shall cease to exist, any Event of Default
arising therefrom shall be deemed to have been cured for every purpose of the
Indenture, and the Issuers, the Trustee and the Holders of the Debt Securities
of that series shall be restored to their former positions and rights hereunder,
respectively; but no such waiver shall extend to any subsequent or other Default
or impair any right consequent thereon.

                  SECTION 6.07. Trustee to Give Notice of Defaults Known to It,
                                -----------------------------------------------
but May Withhold Such Notice in Certain Circumstances. The Trustee shall, within
-----------------------------------------------------
90 days after the occurrence of a Default known to it with respect to a series
of Debt Securities give to the Holders thereof, in the manner provided in
Section 12.03, notice of all Defaults with respect to such series known to the
Trustee, unless such Defaults shall have been cured or waived before the giving
of such notice; provided that, except in the case of Default in the payment of
                --------
the principal of, or premium, if any, or interest on, any of the Debt Securities
of such series or in the making of any sinking fund payment with respect to the
Debt Securities of such series, the Trustee shall be protected in withholding
such notice if and so long as the committee of Responsible Officers of the
Trustee in good faith determine that the withholding of such notice is in the
interests of the Holders thereof.

                  SECTION 6.08. Requirement of an Undertaking To Pay Costs in
                                ---------------------------------------------
Certain Suits under the Indenture or Against the Trustee. All parties to the
--------------------------------------------------------
Indenture agree, and each Holder of any Debt Security by his acceptance thereof
shall be deemed to have agreed, that any court may in its discretion require, in
any suit for the enforcement of any right or remedy under the Indenture, or in
any suit against the Trustee for any action taken or omitted by it as Trustee,
the filing by any party litigant in such suit of an undertaking to pay the costs
of such suit in the manner and to the extent provided in the Trust Indenture
Act, and that such court may in its discretion assess reasonable costs,
including reasonable attorneys' fees and expenses, against any party litigant in
such suit, having due regard to the merits and good faith of the claims or
defenses made by such party litigant; but the provisions of this Section 6.08
shall not apply to any suit instituted by the Trustee, to any suit instituted by
any Holder, or group of Holders, holding in the aggregate more than ten percent
in principal amount of the Outstanding Debt Securities of that series or to any
suit instituted by any Holder for the enforcement of the payment of the
principal of, or premium, if any, or interest on, any Debt Security on or after
the due date for such payment expressed in such Debt Security.

                                       38
<PAGE>

                                  ARTICLE VII

                            Concerning the Trustee
                            ----------------------

                  SECTION 7.01. Certain Duties and Responsibilities. The
                                -----------------------------------
Trustee, prior to the occurrence of an Event of Default and after the curing or
waiving of all Events of Default which may have occurred, undertakes to perform
such duties and only such duties as are specifically set forth in the Indenture.
In case an Event of Default has occurred (which has not been cured or waived),
the Trustee shall exercise such of the rights and powers vested in it by the
Indenture, and use the same degree of care and skill in their exercise, as a
prudent person would exercise or use under the circumstances in the conduct of
his own affairs.

                  No provision of the Indenture shall be construed to relieve
the Trustee from liability for its own negligent action, its own negligent
failure to act, or its own willful misconduct, except that:

                  (a)  this subsection shall not be construed to limit the
         effect of the first paragraph of this Section 7.01;

                  (b)  prior to the occurrence of an Event of Default with
         respect to the Debt Securities of a series and after the curing or
         waiving of all Events of Default with respect to such series which may
         have occurred:

                       (1)  the duties and obligations of the Trustee with
                  respect to Debt Securities of any series shall be determined
                  solely by the express provisions of the Indenture, and the
                  Trustee shall not be liable except for the performance of such
                  duties and obligations with respect to such series as are
                  specifically set forth in the Indenture, and no implied
                  covenants or obligations with respect to such series shall be
                  read into the Indenture against the Trustee; and

                       (2)  in the absence of bad faith on the part of the
                  Trustee, the Trustee may conclusively rely, as to the truth of
                  the statements and the correctness of the opinions expressed
                  therein, upon any certificates or opinions furnished to the
                  Trustee and conforming to the requirements of the Indenture;
                  but in the case of any such certificates or opinions which by
                  any provision hereof are specifically required to be furnished
                  to the Trustee, the Trustee shall be under a duty to examine
                  the same to determine whether or not they conform to the
                  requirements of the Indenture;

                  (c)  the Trustee shall not be liable for an error of judgment
         made in good faith by a Responsible Officer, unless it shall be proved
         that the Trustee was negligent in ascertaining the pertinent facts; and

                  (d)  the Trustee shall not be liable with respect to any
         action taken or omitted to be taken by it with respect to Debt
         Securities of any series in good faith in accordance with the direction
         of the Holders of not less than a majority in aggregate principal
         amount of the Outstanding Debt Securities of that series relating to
         the time, method and place of conducting any proceeding for any remedy
         available to the Trustee, or exercising any

                                       39
<PAGE>

         trust or power conferred upon the Trustee, under the Indenture with
         respect to Debt Securities of such series.

                  None of the provisions of the Indenture shall require the
Trustee to expend or risk its own funds or otherwise incur any personal
financial liability in the performance of any of its duties hereunder, or in the
exercise of any of its rights or powers, if there shall be reasonable grounds
for believing that repayment of such funds or adequate indemnity against such
risk or liability is not reasonably assured to it.

                  Whether or not therein expressly so provided, every provision
of the Indenture relating to the conduct or affecting the liability of or
affording protection to the Trustee shall be subject to the provisions of this
Section.

                  SECTION 7.02. Certain Rights of Trustee. Except as otherwise
                                -------------------------
provided in Section 7.01:

                  (a)  the Trustee may conclusively rely and shall be fully
         protected in acting or refraining from acting upon any resolution,
         certificate, statement, instrument, opinion, report, notice, request,
         direction, consent, order, bond, debenture, note or other paper or
         document (whether in its original or facsimile form) believed by it to
         be genuine and to have been signed or presented by the proper party or
         parties;

                  (b)  any request, direction, order or demand of the Issuers
         mentioned herein shall be sufficiently evidenced by an Issuer Order
         (unless other evidence in respect thereof be herein specifically
         prescribed); and any Board Resolution may be evidenced to the Trustee
         by a copy thereof certified by the Secretary or an Assistant Secretary
         of each of the Managing General Partner and PAA Finance;

                  (c)  the Trustee may consult with counsel of its own
         selection, and the advice of such counsel or any Opinion of Counsel
         shall be full and complete authorization and protection in respect of
         any action taken or suffered or omitted by it hereunder in good faith
         and in accordance with such advice or Opinion of Counsel;

                  (d)  the Trustee shall be under no obligation to exercise any
         of the rights or powers vested in it by the Indenture at the request,
         order or direction of any of the Holders of Debt Securities of any
         series pursuant to the provisions of the Indenture, unless such Holders
         shall have offered to the Trustee security or indemnity reasonably
         satisfactory to it against the costs, expenses and liabilities which
         may be incurred therein or thereby;

                  (e)  the Trustee shall not be liable for any action taken or
         omitted by it in good faith and reasonably believed by it to be
         authorized or within the discretion or rights or powers conferred upon
         it by the Indenture;

                  (f)  prior to the occurrence of an Event of Default and after
         the curing of all Events of Default which may have occurred, the
         Trustee shall not be bound to make any investigation into the facts or
         matters stated in any resolution, certificate, statement, instrument,
         opinion, report, notice, request, direction, consent, order, approval
         or other

                                       40
<PAGE>

     paper or document, unless requested in writing to do so by the Holders of a
     majority in aggregate principal amount of the then outstanding Debt
     Securities of a series affected by such matter; provided, however, that if
                                                     --------  -------
     the payment within a reasonable time to the Trustee of the costs, expenses
     or liabilities likely to be incurred by it in the making of such
     investigation is not, in the opinion of the Trustee, reasonably assured to
     the Trustee by the security afforded to it by the terms of the Indenture,
     the Trustee may require indemnity reasonably satisfactory to it against
     such costs, expenses or liabilities as a condition to so proceeding; the
     Trustee shall be entitled to examine the books, records and premises of the
     Issuers during ordinary business hours and for any purpose relevant to the
     Indenture, personally or by an agent or attorney at the sole cost of the
     Issuers and shall incur no liability or additional liability of any kind by
     reason of such inquiry or investigation;

          (g)  the Trustee may execute any of the trusts or powers hereunder or
     perform any duties hereunder either directly or by or through agents or
     attorneys and the Trustee shall not be responsible for any misconduct or
     negligence on the part of any agent or attorney appointed by it with due
     care hereunder;

          (h)  if any property other than cash shall at any time be subject to a
     Lien in favor of the Holders, the Trustee, if and to the extent authorized
     by a receivership or bankruptcy court of competent jurisdiction or by the
     supplemental instrument subjecting such property to such Lien, shall be
     entitled to make advances for the purpose of preserving such property or of
     discharging tax Liens or other prior Liens or encumbrances thereon; and

          (i)  the Trustee shall not be deemed to have notice of any Default or
     Event of Default unless a Responsible Officer of the Trustee has actual
     knowledge thereof or unless written notice of any event which is in fact
     such a Default is received by the Trustee at the Corporate Trust Office of
     the Trustee, and such notice references the Debt Securities and the
     Indenture; and

          (j)  the rights, privileges, protections, immunities and benefits
     given to the Trustee, including, without limitation, its right to be
     indemnified, are extended to, and shall be enforceable by, the Trustee in
     each of its capacities hereunder, and to each agent, custodian and other
     Person employed by the Trustee to act hereunder.

          SECTION 7.03. Trustee Not Liable for Recitals in Indenture or in Debt
                        -------------------------------------------------------
Securities. The recitals contained herein and in the Debt Securities (except the
----------
Trustee's certificate of authentication) shall be taken as the statements of the
Issuers, and the Trustee assumes no responsibility for the correctness of the
same. The Trustee makes no representations as to the validity or sufficiency of
the Indenture or of the Debt Securities of any series, except that the Trustee
represents that it is duly authorized to execute and deliver the Indenture,
authenticate the Debt Securities and perform its obligations hereunder, and that
the statements made by it or to be made by it in a Statement of Eligibility and
Qualification on Form T-1 supplied to the Issuers are true and accurate. The
Trustee shall not be accountable for the use or application by the Issuers of
any of the Debt Securities or of the proceeds thereof.

                                       41
<PAGE>

          SECTION 7.04. Trustee, Paying Agent or Registrar May Own Debt
                        -----------------------------------------------
Securities. The Trustee or any paying agent or Registrar, in its individual or
----------
any other capacity, may become the owner or pledgee of Debt Securities and
subject to the provisions of the Trust Indenture Act relating to conflicts of
interest and preferential claims may otherwise deal with the Issuers with the
same rights it would have if it were not Trustee, paying agent or Registrar;
provided, however, that if the Trustee acquires any such conflicting interest
--------  -------
and an Event of Default or Default has occurred and is continuing, the Trustee
must eliminate such conflict within 90 days, apply to the Commission for
permission to continue as trustee or resign.

          SECTION 7.05. Moneys Received by Trustee to Be Held in Trust. Subject
                        ----------------------------------------------
to the provisions of Section 11.02, all moneys received by the Trustee shall,
until used or applied as herein provided, be held in trust for the purposes for
which they were received, but need not be segregated from other funds except to
the extent required by law. The Trustee shall be under no liability for interest
on any moneys received by it hereunder. So long as no Event of Default shall
have occurred and be continuing, all interest allowed on any such moneys shall
be paid from time to time to the Issuers upon an Issuer Order.

          SECTION 7.06. Compensation and Reimbursement. The Issuers covenant and
                        ------------------------------
agree to pay in Dollars to the Trustee from time to time, and the Trustee shall
be entitled to, reasonable compensation for all services rendered by it
hereunder (which shall not be limited by any provision of law in regard to the
compensation of a trustee of an express trust), and, except as otherwise
expressly provided herein, the Issuers will pay or reimburse in Dollars the
Trustee upon its request for all expenses, disbursements and advances incurred
or made by the Trustee in accordance with any of the provisions of the Indenture
(including the reasonable compensation and the expenses and disbursements of its
agents, attorneys and counsel and of all Persons not regularly in its employ)
except any such expense, disbursement or advances as may arise from its
negligence or bad faith. The Issuers also covenant to fully indemnify in Dollars
the Trustee and any predecessor Trustee for, and to hold it harmless against,
any and all loss, liability, claim, damage or expense incurred without
negligence or willful misconduct on the part of the Trustee, arising out of or
in connection with the acceptance or administration of this trust or trusts
hereunder, including the costs and expenses of defending itself against any
claim of liability in connection with the exercise or performance of any of its
powers or duties hereunder. The obligations of the Issuers under this Section
7.06 to compensate and indemnify the Trustee and to pay or reimburse the Trustee
for expenses, disbursements and advances shall constitute additional
indebtedness hereunder and shall survive the satisfaction and discharge of the
Indenture. The Issuers and the Holders agree that such additional indebtedness
shall be secured by a Lien prior to that of the Debt Securities upon all
property and funds held or collected by the Trustee, as such, except funds held
in trust for the payment of principal of, and premium, if any, or interest on,
particular Debt Securities.

          When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 6.01(g) or (h) occurs, the expenses and the
compensation for the services are intended to constitute expenses of
administration under any bankruptcy, insolvency, reorganization or other similar
law.

          SECTION 7.07. Right of Trustee to Rely on an Officers' Certificate
                        ----------------------------------------------------
Where No Other Evidence Specifically Prescribed. Except as otherwise provided in
-----------------------------------------------
Section 7.01, whenever

                                       42
<PAGE>

in the administration of the provisions of the Indenture the Trustee shall deem
it necessary or desirable that a matter be proved or established prior to taking
or suffering or omitting any action hereunder, such matter (unless other
evidence in respect thereof be herein specifically prescribed) may, in the
absence of negligence or bad faith on the part of the Trustee, be deemed to be
conclusively proved and established by an Officers' Certificate delivered to the
Trustee and such certificate, in the absence of negligence or bad faith on the
part of the Trustee, shall be full warrant to the Trustee for any action taken,
suffered or omitted by it under the provisions of the Indenture upon the faith
thereof.

          SECTION 7.08. Separate Trustee; Replacement of Trustee. The Issuers
                        ----------------------------------------
may, but need not, appoint a separate Trustee for any one or more series of Debt
Securities. The Trustee may resign with respect to one or more or all series of
Debt Securities at any time by giving notice to the Issuers. The Holders of a
majority in principal amount of the Debt Securities of a particular series may
remove the Trustee for such series and only such series by so notifying the
Trustee and may appoint a successor Trustee. The Issuers shall remove the
Trustee if:

          (1)  the Trustee fails to comply with Section 7.10;

          (2)  the Trustee is adjudged bankrupt or insolvent;

          (3)  a receiver or other public officer takes charge of the Trustee or
     its property; or

          (4)  the Trustee otherwise becomes incapable of acting.

          If the Trustee resigns, is removed by the Issuers or by the Holders of
a majority in principal amount of the Debt Securities of a particular series and
such Holders do not reasonably promptly appoint a successor Trustee, or if a
vacancy exists in the office of Trustee for any reason (the Trustee in such
event being referred to herein as the retiring Trustee), the Issuers shall
promptly appoint a successor Trustee. No resignation or removal of the Trustee
and no appointment of a successor Trustee shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of this Section 7.08.

          A successor Trustee shall deliver a written acceptance of its
appointment to the retiring Trustee and to the Issuers. Thereupon the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under the Indenture. The successor Trustee shall mail a notice of its succession
to Holders of Debt Securities of each applicable series. The retiring Trustee
shall promptly transfer all property held by it as Trustee to the successor
Trustee, subject to the Lien provided for in Section 7.06.

          If a successor Trustee does not take office within 60 days
after the retiring Trustee gives notice of resignation or is removed, the
retiring Trustee or the Holders of 25% in principal amount of the Debt
Securities of any applicable series may petition any court of competent
jurisdiction for the appointment of a successor Trustee for the Debt Securities
of such series.

          If the Trustee fails to comply with Section 7.10, any Holder of Debt
Securities of any applicable series may petition at the expense of the Issuers
any court of competent

                                       43
<PAGE>

jurisdiction for the removal of the Trustee and the appointment of a successor
Trustee for the Debt Securities of such series.

          Notwithstanding the replacement of the Trustee pursuant to this
Section 7.08, the Issuers' obligations under Section 7.06 shall continue for the
benefit of the retiring Trustee.

          In the case of the appointment hereunder of a separate or successor
Trustee with respect to the Debt Securities of one or more series, the Issuers,
any retiring Trustee and each successor or separate Trustee with respect to the
Debt Securities of any applicable series shall execute and deliver an Indenture
supplemental hereto (1) which shall contain such provisions as shall be deemed
necessary or desirable to confirm that all the rights, powers, trusts and duties
of any retiring Trustee with respect to the Debt Securities of any series as to
which any such retiring Trustee is not retiring shall continue to be vested in
such retiring Trustee and (2) that shall add to or change any of the provisions
of the Indenture as shall be necessary to provide for or facilitate the
administration of the trusts hereunder by more than one trustee, it being
understood that nothing herein or in such supplemental Indenture shall
constitute such Trustees co-trustees of the same trust and that each such
separate, retiring or successor Trustee shall be Trustee of a trust or trusts
hereunder separate and apart from any trust or trusts hereunder administered by
any other such Trustee.

          SECTION 7.09.  Successor Trustee by Merger. If the Trustee
                         ---------------------------
consolidates with, merges or converts into, or transfers all or substantially
all of its corporate trust business or assets to, another corporation or banking
association, the resulting, surviving or transferee corporation or banking
association without any further act shall be the successor Trustee, provided
such Person shall be otherwise qualified and eligible under this Article VII,
without the execution or filing of any paper or any further act on the part of
any of the parties hereto. As soon as practicable, the successor Trustee shall
mail a notice of its succession to the Issuers and the Holders of the Debt
Securities then Outstanding.

          In case at the time such successor or successors by merger, conversion
or consolidation to the Trustee shall succeed to the trusts created by the
Indenture any of the Debt Securities shall have been authenticated but not
delivered, any such successor to the Trustee may adopt the certificate of
authentication of any predecessor trustee, and deliver such Debt Securities so
authenticated; and in case at that time any of the Debt Securities shall not
have been authenticated, any successor to the Trustee may authenticate such Debt
Securities either in the name of any predecessor hereunder or in the name of the
successor to the Trustee; and in all such cases such certificates shall have the
full force which it is anywhere in the Debt Securities or in the Indenture
provided that the certificate of the Trustee shall have.

          SECTION 7.10. Eligibility; Disqualification. The Trustee shall at all
                        -----------------------------
times satisfy the requirements of Section 310(a) of the Trust Indenture Act. The
Trustee shall have a combined capital and surplus of at least $50,000,000, as
set forth in its most recently published annual report of condition. No obligor
upon the Debt Securities of a particular series or Person directly or indirectly
controlling, controlled by or under common control with such obligor shall serve
as Trustee upon the Debt Securities of such series. The Trustee shall comply
with Section 310(b) of the Trust Indenture Act; provided, however, that there
                                                --------  -------
shall be excluded from the operation of Section 310(b)(1) of the Trust Indenture
Act the Indenture or

                                       44
<PAGE>

any indenture or indentures under which other securities or certificates of
interest or participation in other securities of the Issuers are outstanding if
the requirements for such exclusion set forth in Section 310(b)(1) of the Trust
Indenture Act are met.

          SECTION 7.11. Preferential Collection of Claims Against Issuers. The
                        -------------------------------------------------
Trustee shall comply with Section 311(a) of the Trust Indenture Act, excluding
any creditor relationship listed in Section 311(b) of the Trust Indenture Act. A
Trustee who had resigned or been removed shall be subject to Section 311(a) of
the Trust Indenture Act to the extent indicated therein.

          SECTION 7.12. Compliance with Tax Laws. The Trustee hereby agrees to
                        ------------------------
comply with all U.S. Federal income tax information reporting and withholding
requirements applicable to it with respect to payments of principal, premium (if
any) and interest on the Debt Securities, whether acting as Trustee, Security
Registrar, paying agent or otherwise with respect to the Debt Securities.

                                 ARTICLE VIII

                            Concerning the Holders
                            ----------------------

          SECTION 8.01. Evidence of Action by Holders. Whenever in the Indenture
                        -----------------------------
it is provided that the Holders of a specified percentage in aggregate principal
amount of the Debt Securities of any or all series may take action (including
the making of any demand or request, the giving of any direction, notice,
consent or waiver or the taking of any other action) the fact that at the time
of taking any such action the Holders of such specified percentage have joined
therein may be evidenced (a) by any instrument or any number of instruments of
similar tenor executed by Holders in person or by agent or proxy appointed in
writing, (b) by the record of the Holders voting in favor thereof at any meeting
of Holders duly called and held in accordance with the provisions of Section
5.02 or (c) by a combination of such instrument or instruments and any such
record of such a meeting of Holders.

          SECTION 8.02. Proof of Execution of Instruments and of Holding of Debt
                        --------------------------------------------------------
Securities. Subject to the provisions of Sections 7.01, 7.02 and 12.09, proof of
----------
the execution of any instrument by a Holder or his agent or proxy shall be
sufficient if made in accordance with such reasonable rules and regulations as
may be prescribed by the Trustee or in such manner as shall be satisfactory to
the Trustee.

          The ownership of Registered Securities of any series shall be proved
by the Debt Security Register or by a certificate of the Registrar for such
series.

          The Trustee may require such additional proof of any matter referred
to in this Section 8.02 as it shall deem necessary.

          SECTION 8.03. Who May Be Deemed Owner of Debt Securities. Prior to due
                        ------------------------------------------
presentment for registration of transfer of any Registered Security, the
Issuers, the Trustee, any paying agent and any Registrar may deem and treat the
Person in whose name any Registered Security shall be registered upon the books
of the Issuers as the absolute owner of such Registered Security (whether or not
such Registered Security shall be overdue and

                                       45
<PAGE>

notwithstanding any notation of ownership or other writing thereon) for the
purpose of receiving payment of or on account of the principal of and premium,
if any, and (subject to Section 2.12) interest on such Registered Security and
for all other purposes, and neither the Issuers nor the Trustee nor any paying
agent nor any Registrar shall be affected by any notice to the contrary; and all
such payments so made to any such Holder for the time being, or upon his order,
shall be valid and, to the extent of the sum or sums so paid, effectual to
satisfy and discharge the liability for moneys payable upon any such Registered
Security.

          SECTION 8.04. Instruments Executed by Holders Bind Future Holders. At
                        ---------------------------------------------------
any time prior to (but not after) the evidencing to the Trustee, as provided in
Section 8.01, of the taking of any action by the Holders of the percentage in
aggregate principal amount of the Debt Securities of any series specified in the
Indenture in connection with such action and subject to the following paragraph,
any Holder of a Debt Security which is shown by the evidence to be included in
the Debt Securities the Holders of which have consented to such action may, by
filing written notice with the Trustee at its Corporate Trust Office of the
Trustee and upon proof of holding as provided in Section 8.02, revoke such
action so far as concerns such Debt Security. Except as aforesaid any such
action taken by the Holder of any Debt Security shall be conclusive and binding
upon such Holder and upon all future Holders and owners of such Debt Security
and of any Debt Security issued upon transfer thereof or in exchange or
substitution therefor, irrespective of whether or not any notation in regard
thereto is made upon such Debt Security or such other Debt Securities. Any
action taken by the Holders of the percentage in aggregate principal amount of
the Debt Securities of any series specified in the Indenture in connection with
such action shall be conclusively binding upon the Issuers, the Trustee and the
Holders of all the Debt Securities of such series.

          The Issuers may, but shall not be obligated to, fix a record date for
the purpose of determining the Holders of Registered Securities entitled to give
their consent or take any other action required or permitted to be taken
pursuant to the Indenture. If a record date is fixed, then notwithstanding the
immediately preceding paragraph, those Persons who were Holders of Registered
Securities at such record date (or their duly designated proxies), and only
those Persons, shall be entitled to give such consent or to revoke any consent
previously given or to take any such action, whether or not such Persons
continue to be Holders of Registered Securities after such record date. No such
consent shall be valid or effective for more than 120 days after such record
date unless the written consent of the Holders of the percentage in aggregate
principal amount of the Debt Securities of such series specified in the
Indenture shall have been received within such 120-day period.

                                  ARTICLE IX

                       Amendment, Supplement and Waiver
                       --------------------------------

          SECTION 9.01. Without Consent of Holders of Debt Securities. The
                        ---------------------------------------------
Issuers and the Trustee may from time to time and at any time, without the
consent of Holders, enter into an Indenture or Indentures supplemental hereto
(which shall conform to the provisions of the Trust Indenture Act as in force at
the date of the execution thereof) for one or more of the following purposes:

                                       46
<PAGE>

          (a)  to cure any ambiguity, defect or inconsistency contained herein,
     in any supplemental Indenture or in the Debt Securities of such series;

          (b)  to provide for uncertificated Debt Securities in addition to or
     in place of certificated Debt Securities; provided, however, that the
                                               --------  -------
     uncertificated Debt Securities are issued in registered form for purposes
     of Section 163(f) of the Code, or in a manner such that the uncertificated
     Debt Securities are described in Section 163(f)(2)(B) of the Code;

          (c)  to provide for the assumption of an Issuer's obligations to
     Holders pursuant to Article X;

          (d)  to add guarantors with respect to the Debt Securities as parties
     to the Indenture or to release guarantors in accordance with the provisions
     of any supplemental Indenture;

          (e)  to make any changes that would provide any additional rights or
     benefits to the Holders of the Debt Securities or that do not, taken as a
     whole, adversely affect the legal rights hereunder of any Holder;

          (f)  to comply with the requirements of the Commission to permit the
     qualification of the Indenture or any Indenture supplemental hereto under
     the Trust Indenture Act as then in effect, except that nothing herein
     contained shall permit or authorize the inclusion in any Indenture
     supplemental hereto of the provisions referred to in Section 316(a)(2) of
     the Trust Indenture Act;

          (g)  to evidence or provide for the acceptance of appointment
     hereunder by a successor or separate Trustee with respect to the Debt
     Securities of one or more series and to add to or change any of the
     provisions of the Indenture as shall be necessary to provide for or
     facilitate the administration of the trusts hereunder by more than one
     Trustee;

          (h)  to add any additional Events of Default;

          (i)  to make any changes in Article XIII that would limit or terminate
     the benefits applicable to any holder of Senior Indebtedness (or its
     Representatives) under Article XIII;

          (j)  to secure the Debt Securities and/or any guarantee with respect
     to any Debt Securities; and

          (k)  to establish the form or terms of the Debt Securities as
     permitted by Section 2.01 or 2.03.

          The Trustee is hereby authorized to join with the Issuers and
guarantors with respect to any Debt Securities in the execution of any such
supplemental Indenture, to make any further appropriate agreements and
stipulations which may be therein contained and to accept the conveyance,
transfer, assignment, mortgage or pledge of any property thereunder, but the
Trustee

                                       47
<PAGE>

shall not be obligated to enter into any such supplemental Indenture which
affects the Trustee's own rights, duties or immunities under the Indenture or
otherwise.

          Any supplemental Indenture authorized by the provisions of this
Section 9.01 may be executed by the Issuers, any guarantors with respect to any
Debt Securities and the Trustee without the consent of the Holders of any of the
Debt Securities at the time outstanding, notwithstanding any of the provisions
of Section 9.02.

          After an amendment under this Section 9.01 becomes effective, the
Issuers shall mail to Holders of Debt Securities of each series affected thereby
a notice briefly describing such amendment. The failure to give such notice to
all such Holders, or any defect therein, shall not impair or affect the validity
of an amendment under this Section 9.01.

          SECTION 9.02. With Consent of Holders of Debt Securities. Without
                        ------------------------------------------
notice to any Holder but with the consent (evidenced as provided in Section
8.01) of the Holders of a majority in aggregate principal amount of the
outstanding Debt Securities of each series affected by such supplemental
Indenture, (a) the Issuers, when authorized by Board Resolutions, and the
Trustee may from time to time and at any time enter into an Indenture or
Indentures supplemental hereto (which shall conform to the provisions of the
Trust Indenture Act as in force at the date of execution thereof) for the
purpose of adding any provisions to or changing in any manner or eliminating any
of the provisions of the Indenture or of any supplemental Indenture or of
modifying in any manner the rights of the Holders of the Debt Securities of such
series, and (b) subject to the Sections 6.04 and 6.08, any existing Default or
Events of Default or compliance with any provision of the Indenture or the Debt
Securities of such series may be waived; provided, that no such supplemental
                                         --------
Indenture or waiver, without the consent of the Holders of each Debt Security so
affected, shall (i) reduce the percentage in principal amount of Debt Securities
of any series whose Holders must consent to an amendment, supplement or waiver;
(ii) reduce the principal of or change the Stated Maturity of any Debt Security;
(iii) reduce or waive the premium payable upon the redemption of any Debt
Security or alter or waive any provisions by which any Debt Security may or
shall be redeemed in accordance with Article III (other than provisions
requiring the repurchase of the Debt Securities of such series if so permitted
by the Board Resolutions or supplemental Indenture establishing the terms of
such series); (iv) reduce the rate of or change the time for payment of interest
on any Debt Security; (v) waive a Default or an Event of Default in the payment
of principal of, or premium, if any, or interest on a Debt Security except for a
rescission of an acceleration of such Debt Securities by the Holders of at least
a majority in aggregate principal amount of such Debt Securities and a waiver of
the payment default that resulted from such acceleration; (vi) except as
otherwise permitted under the Indenture, release any security that may have been
granted in respect of the Debt Securities; (vii) make any Debt Security payable
in Currency other than that stated in the Debt Security; (viii) make any change
in the provisions of the Indenture relating to waivers of past Defaults or the
rights of Holders to receive payments of principal of or premium, if any, or
interest on the Debt Securities; (ix) waive a redemption payment with respect to
any Debt Security (other than a payment required by a covenant requiring the
repurchase of the Debt Securities of such series if so permitted by the Board
Resolutions or supplemental Indenture establishing the terms of such series);
(x) except as otherwise permitted under the Indenture with respect to Debt
Securities that are guaranteed, release any guarantor from its obligations under
the Indenture or under its guarantee or change any guarantee in any manner that
would adversely

                                       48
<PAGE>

affect the rights of Holders of such Debt Securities; (xi) make any change in
Article XIII that adversely affects the rights of any Holder under Article XIII;
or (xii) make any change in Section 6.06 or this Section 9.02.

          A supplemental Indenture which changes or eliminates any covenant or
other provision of the Indenture which has been expressly included solely for
the benefit of one or more particular series of Debt Securities or which
modifies the rights of the Holders of Debt Securities of such series with
respect to such covenant or other provision, shall be deemed not to affect the
rights under the Indenture of the Holders of Debt Securities of any other
series.

          Upon the request of the Issuers, accompanied by copies of Board
Resolutions authorizing the execution of any such supplemental Indenture, and
upon the filing with the Trustee of evidence of the consent of Holders as
aforesaid, the Trustee shall join with the Issuers and any guarantors with
respect to any Debt Securities in the execution of such supplemental Indenture
unless such supplemental Indenture affects the Trustee's own rights, duties or
immunities under the Indenture or otherwise, in which case the Trustee may in
its discretion but shall not be obligated to enter into such supplemental
Indenture.

          It shall not be necessary for the consent of the Holders under this
Section 9.02 to approve the particular form of any proposed supplemental
Indenture, but it shall be sufficient if such consent shall approve the
substance thereof.

          An amendment under this Section 9.02 may not make any change that
adversely affects the rights under Article XIII of any holder of Senior
Indebtedness then Outstanding unless the holders of such Senior Indebtedness (or
any group or Representative thereof authorized to give a consent) consents to
such change.

          After an amendment or waiver under this Section 9.02 becomes
effective, the Issuers shall mail to Holders of Debt Securities of each series
affected thereby a notice briefly describing such amendment or waiver. The
failure to give such notice to all such Holders, or any defect therein, shall
not impair or affect the validity of an amendment or waiver under this Section
9.02.

          SECTION 9.03. Effect of Supplemental Indentures. Upon the execution of
                        ---------------------------------
any supplemental Indenture pursuant to the provisions of this Article IX, the
Indenture shall be and be deemed to be modified and amended in accordance
therewith and the respective rights, limitations of rights, obligations, duties
and immunities under the Indenture of the Trustee, the Issuers and the Holders
shall thereafter be determined, exercised and enforced hereunder subject in all
respects to such modifications and amendments, and all the terms and conditions
of any such supplemental Indenture shall be and be deemed to be part of the
terms and conditions of the Indenture for any and all purposes.

          The Trustee, subject to the provisions of Sections 7.01 and 7.02, may
receive an Officers' Certificate and an Opinion of Counsel as conclusive
evidence that any such supplemental Indenture complies with the provisions of
this Article IX.

          SECTION 9.04. Debt Securities May Bear Notation of Changes by
                        -----------------------------------------------
Supplemental Indentures. Debt Securities of any series authenticated and
-----------------------
delivered after the

                                       49
<PAGE>

execution of any supplemental Indenture pursuant to the provisions of this
Article IX may, and shall if required by the Trustee, bear a notation in form
approved by the Trustee as to any matter provided for in such supplemental
Indenture. New Debt Securities of any series so modified as to conform, in the
opinion of the Trustee and the Board of Directors, to any modification of the
Indenture contained in any such supplemental Indenture may be prepared and
executed by the Issuers, authenticated by the Trustee and delivered in exchange
for the Debt Securities of such series then outstanding. Failure to make the
appropriate notation or to issue a new Debt Security of such series shall not
affect the validity of such amendment.

                                   ARTICLE X

                   Consolidation, Merger, Sale or Conveyance
                   -----------------------------------------

          SECTION 10.01. Consolidations and Mergers of the Issuers. Neither of
                         -----------------------------------------
the Issuers may, directly or indirectly: (1) consolidate or merge with or into
another Person (whether or not such Issuer is the survivor); or (2) sell,
assign, transfer, lease, convey or otherwise dispose of all or substantially all
of its properties or assets, in one or more related transactions, to another
Person; unless:

          (1)  either (a) such Issuer is the surviving entity of such
transaction; or (b) the Person formed by or surviving any such consolidation or
merger (if other than such Issuer) or to which such sale, assignment, transfer,
lease, conveyance or other disposition shall have been made (the "Successor
Company") is an entity organized or existing under the laws of the United
States, any state thereof or the District of Columbia, provided that PAA Finance
                                                       --------
may not consolidate or merge with or into any entity other than a corporation
satisfying such requirement for so long as the Partnership is not a corporation;

          (2)  the Successor Company assumes all the obligations of such Issuer
under the notes and the Indenture pursuant to agreements reasonably satisfactory
to the Trustee;

          (3)  immediately after such transaction no Default or Event of Default
exists; and

          (4)  such Issuer has delivered to the Trustee an Officers' Certificate
and an Opinion of Counsel, each stating that such consolidation, merger or
transfer and, if a supplemental Indenture is required, such supplemental
Indenture complies with the Indenture and all conditions precedent therein
relating to such transaction have been satisfied.

          SECTION 10.02. Rights and Duties of Successor Company. In case of any
                         --------------------------------------
consolidation, merger or disposition respecting an Issuer in accordance with
Section 10.01, the Successor Company shall succeed to and be substituted for
such Issuer, with the same effect as if it had been named herein as the party of
the first part, and the Issuer shall be relieved of any further obligation under
the Indenture and the Debt Securities. The Successor Company thereupon may cause
to be signed, and may issue either in its own name or in the name of such
Issuer, any or all the Debt Securities issuable hereunder which theretofore
shall not have been signed by such Issuer and delivered to the Trustee; and,
upon the order of the Successor Company, instead of such Issuer, and subject to
all the terms, conditions and limitations in the

                                       50
<PAGE>

Indenture prescribed, the Trustee shall authenticate and shall deliver any Debt
Securities which previously shall have been signed and delivered by the officers
of such Issuer or its Managing General Partner, as the case may be, to the
Trustee for authentication, and any Debt Securities which the Successor Company
thereafter shall cause to be signed and delivered to the Trustee for that
purpose. All the Debt Securities so issued shall in all respects have the same
legal rank and benefit under the Indenture as the Debt Securities theretofore or
thereafter issued in accordance with the terms of the Indenture as though all
such Debt Securities had been issued at the date of the execution hereof.

          In case of any such consolidation, merger or disposition such changes
in phraseology and form (but not in substance) may be made in the Debt
Securities appertaining thereto thereafter to be issued as may be appropriate.

                                  ARTICLE XI

                   Satisfaction and Discharge of Indenture;
                   ----------------------------------------
                               Unclaimed Moneys
                               ----------------

          SECTION 11.01. Satisfaction and Discharge; Application of Trust Money.
                         ------------------------------------------------------
The Indenture shall upon the request of the Issuers cease to be of further
effect with respect to all Outstanding Debt Securities of any series (except as
to surviving rights of registration of transfer or exchange of Debt Securities
of such series herein expressly provided for, the Issuers' obligations under
Section 7.06, and the Trustee's and each paying agent's obligations under the
last paragraph of this Section 11.01 and Section 11.02) and the Trustee, on
demand and at the expense of the Issuers, shall execute proper instruments
acknowledging satisfaction and discharge of the Indenture with respect to such
series, when:

          (a)  either

               (i)  all outstanding Debt Securities of such series therefore
     authenticated and delivered (other than (A) Debt Securities which have been
     destroyed, lost or stolen and which have been replaced or paid as provided
     in Section 2.09 and (B) Debt Securities for whose payment money has been
     deposited in trust with the Trustee or any paying agent and thereafter
     repaid to either Issuer or discharged from such trust) have been delivered
     to the Trustee for cancellation; or

               (ii) all outstanding Debt Securities of such series not
     theretofore delivered to the Trustee for cancellation

                    (A)  have become due and payable by reason of the giving of
          a notice of redemption or otherwise,

                    (B)  shall become due and payable at their Stated Maturity
          within one year, or

                    (C)  are to be called for redemption within one year under
          arrangements satisfactory to the Trustee for the giving of notice of
          redemption by the Trustee in the name, and at the expense, of the
          Issuers,

                                       51
<PAGE>

          and the Issuers, in the case of clause (A), (B) or (C) above, have
          irrevocably deposited or caused to be irrevocably deposited with the
          Trustee as trust funds in trust for such purpose cash in Dollars or
          U.S. Government Obligations, or a combination thereof, in an amount
          sufficient (without consideration of any reinvestment of interest and
          as certified by an independent public accountant designated by the
          Partnership expressed in a written certification thereof delivered to
          the Trustee) to pay and discharge the entire indebtedness of such Debt
          Securities not theretofore delivered to the Trustee for cancellation,
          for principal (and premium, if any) and accrued and unpaid interest to
          the date of such deposit (in the case of Debt Securities which have
          become due and payable) or the Stated Maturity or redemption date, as
          the case may be;

          (b)  the Issuers have paid or caused to be paid all other sums then
     due and payable hereunder by them under the Indenture; and

          (c)  the Partnership has delivered to the Trustee an Officers'
     Certificate and an Opinion of Counsel, each stating that all conditions
     precedent herein provided for relating to the satisfaction and discharge of
     the Indenture have been complied with.

In order to have money available on a payment date to pay principal (and
premium, if any, on) and interest on the Notes, the U.S. Government Obligations
shall be payable as to principal (and premium, if any) or interest at least one
Business Day before such payment date in such amounts as shall provide the
necessary money.

          The Trustee shall hold in trust money or U.S. Government Obligations
deposited with it pursuant to this Article XI. It shall apply the deposited
money and the money from U.S. Government Obligations through any paying agent
and in accordance with the Indenture to the payment of principal of, and
premium, if any, and interest on, the Debt Securities of the defeased series.
Prior to the maturity of such series, the Trustee may, at the written direction
of the Issuers, invest such money in U.S. Government Obligations.

          SECTION 11.02. Repayment to Issuers. The Trustee and any paying agent
                         --------------------
shall promptly turn over to the Issuers upon request any excess money or
securities held by them at any time.

          Subject to any applicable abandoned property law, the Trustee and any
paying agent shall pay to the Issuers upon request any money held by them for
the payment of principal, premium or interest that remains unclaimed for two
years, and, thereafter, Holders entitled to such money must look to the Issuers
for payment as general creditors.

          SECTION 11.03. Indemnity for U.S. Government Obligations. The Issuers
                         -----------------------------------------
shall pay and shall indemnify the Trustee and the Holders against any tax, fee
or other charge imposed on or assessed against deposited U.S. Government
Obligations or the principal and interest received on such U.S. Government
Obligations.

          SECTION 11.04. Reinstatement. If the Trustee or any paying agent is
                         -------------
unable to apply any money or U.S. Government Obligations in accordance with this
Article XI by reason of any legal proceeding or by reason of any order or
judgment of any court or government

                                       52
<PAGE>

authority enjoining, restraining or otherwise prohibiting such application, the
Issuers' obligations under the Indenture and the Debt Securities of the defeased
series shall be revived and reinstated as though no deposit had occurred
pursuant to this Article XI until such time as the Trustee or any paying agent
is permitted to apply all such money or U.S. Government Obligations in
accordance with this Article XI.

                                  ARTICLE XII

                           Miscellaneous Provisions
                           ------------------------

          SECTION 12.01. Successors and Assigns of Issuers Bound by Indenture.
                         ----------------------------------------------------
All the covenants, stipulations, promises and agreements in the Indenture
contained by or in behalf of the Issuers or the Trustee shall bind their
respective successors and assigns, whether so expressed or not.

          SECTION 12.02. Acts of Board, Committee or Officer of Successor
                         ------------------------------------------------
Company Valid. Any act or proceeding by any provision of the Indenture
-------------
authorized or required to be done or performed by any Board of Directors,
committee thereof or officer of the Managing General Partner or PAA Finance, as
applicable, shall and may be done and performed with like force and effect by
the like Board of Directors, committee thereof or officer of any Successor
Company.

          SECTION 12.03. Required Notices or Demands. Except as otherwise
                         ---------------------------
expressly provided in the Indenture, any notice or demand which by any provision
of the Indenture is required or permitted to be given or served by the Trustee
or by the Holders to or on the Issuers shall be in writing in the English
language and may be given or served by being deposited postage prepaid in a post
office letter box in the United States addressed (until another address is filed
by the Issuers with the Trustee) as follows: Plains All American Pipeline, L.P.,
333 Clay Street, Suite 2900, Houston, Texas 77002, Attention: General Counsel.
Except as otherwise expressly provided in the Indenture, any notice, direction,
request or demand by the Issuers or by any Holder to or upon the Trustee shall
be in writing in the English language and may be given or made, for all
purposes, by being deposited, postage prepaid, in a post office letter box in
the United States addressed to the Corporate Trust Office of the Trustee
initially at 5847 San Felipe, Suite 1050, Houston, Texas 77057, Attention:
Corporate Trust Group. The Issuers or the Trustee by notice to the other may
designate additional or different addresses for subsequent notices or
communications.

          Any notice required or permitted to a Registered Holder by the Issuers
or the Trustee pursuant to the provisions of the Indenture shall be in writing
in the English language and shall be deemed to be properly mailed by being
deposited postage prepaid in a post office letter box in the United States
addressed to such Holder at the address of such Holder as shown on the Debt
Security Register. Any report pursuant to Section 313 of the Trust Indenture Act
shall be transmitted in compliance with subsection (c) therein.

          In the event of suspension of regular mail service or by reason of any
other cause it shall be impracticable to give notice by mail, then such
notification as shall be given with the approval of the Trustee shall constitute
sufficient notice for every purpose thereunder.

                                       53
<PAGE>

          Failure to mail a notice or communication to a Holder or any defect in
it or any defect in any notice by publication as to a Holder shall not affect
the sufficiency of such notice with respect to other Holders. If a notice or
communication is mailed or published in the manner provided above, it is
conclusively presumed duly given.

          SECTION 12.04. Indenture and Debt Securities to Be Construed in
                         ------------------------------------------------
Accordance with the Laws of the State of New York. The Indenture and each Debt
-------------------------------------------------
Security shall be deemed to be New York contracts, and for all purposes shall be
construed in accordance with the laws of said State.

          SECTION 12.05. Officers' Certificate and Opinion of Counsel to Be
                         --------------------------------------------------
Furnished upon Application or Demand by the Issuers. Upon any application or
---------------------------------------------------
demand by the Issuers to the Trustee to take any action under any of the
provisions of the Indenture, the Issuers shall furnish to the Trustee an
Officers' Certificate stating that all conditions precedent provided for in the
Indenture relating to the proposed action have been complied with and an Opinion
of Counsel stating that, in the opinion of such counsel, all such conditions
precedent have been complied with, except that in the case of any such
application or demand as to which the furnishing of such document is
specifically required by any provision of the Indenture relating to such
particular application or demand, no additional certificate or opinion need be
furnished.

          Each certificate or opinion provided for in the Indenture and
delivered to the Trustee with respect to compliance with a condition or covenant
provided for in the Indenture shall include (1) a statement that the Person
making such certificate or opinion has read such covenant or condition, (2) a
brief statement as to the nature and scope of the examination or investigation
upon which the statements or opinions contained in such certificate or opinion
are based, (3) a statement that, in the opinion of such Person, he has made such
examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with and (4) a statement as to whether or not, in the opinion of such
Person, such condition or covenant has been complied with.

          SECTION 12.06. Payments Due on Legal Holidays. In any case where the
                         ------------------------------
date of maturity of interest on or principal of and premium, if any, on the Debt
Securities of a series or the date fixed for redemption or repayment of any Debt
Security or the making of any sinking fund payment shall not be a business day
at any Place of Payment for the Debt Securities of such series, then payment of
interest or principal and premium, if any, or the making of such sinking fund
payment need not be made on such date at such Place of Payment, but may be made
on the next succeeding business day at such Place of Payment with the same force
and effect as if made on the date of maturity or the date fixed for redemption,
and no interest shall accrue for the period after such date. If a record date is
not a business day, the record date shall not be affected.

          SECTION 12.07. Provisions Required by Trust Indenture Act to Control.
                         -----------------------------------------------------
If and to the extent that any provision of the Indenture limits, qualifies or
conflicts with another provision included in the Indenture which is required to
be included in the Indenture by any of Sections 310 to 318, inclusive, of the
Trust Indenture Act, such required provision shall control.

                                       54
<PAGE>

          SECTION 12.08. Computation of Interest on Debt Securities. Interest,
                         -------------------------------------------
if any, on the Debt Securities shall be computed on the basis of a 360-day year
of twelve 30-day months, except as may otherwise be provided pursuant to Section
2.03.

          SECTION 12.09. Rules by Trustee, Paying Agent and Registrar. The
                         --------------------------------------------
Trustee may make reasonable rules for action by or a meeting of Holders. The
Registrar and any paying agent may make reasonable rules for their functions.

          SECTION 12.10. No Recourse Against Others. No past, present or future
                         --------------------------
director, officer, partner, employee, incorporator, manager, stockholder,
unitholder or member of the Issuers, the General Partner, the Managing General
Partner or any other obligor on the Debt Securities of any series, as such,
shall have any liability for any obligations of the Issuers or such other
obligors under the Debt Securities, the Indenture or for any claim based on, in
respect of, or by reason of, such obligations or their creation. Each Holder by
accepting a Debt Security waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Debt Securities.

          SECTION 12.11. Severability. In case any provision in the Indenture or
                         ------------
the Debt Securities shall be invalid, illegal or unenforceable, the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby.

          SECTION 12.12. Effect of Headings. The article and section headings
                         ------------------
herein and in the Table of Contents are for convenience only and shall not
affect the construction hereof.

          SECTION 12.13. Indenture May Be Executed in Counterparts. The
                         -----------------------------------------
Indenture may be executed in any number of counterparts, each of which shall be
an original, but such counterparts shall together constitute but one and the
same instrument.

                                 ARTICLE XIII

                       Subordination of Debt Securities
                       --------------------------------

          SECTION 13.01. Applicability of Article; Agreement to Subordinate. The
                         --------------------------------------------------
provisions of this Article XII shall be applicable to the Debt Securities of any
series (Debt Securities of such series being referred to in this Article XIII as
"Subordinated Debt Securities") except to the extent such provisions may be
changed or added to pursuant to Section 2.03. Each Holder by accepting a
Subordinated Debt Security agrees that the indebtedness evidenced by such
Subordinated Debt Security is subordinated in right of payment, to the extent
and in the manner provided in this Article XIII, to the prior payment of all
Senior Indebtedness and that the subordination is for the benefit of and
enforceable by the holders of Senior Indebtedness. All provisions of this
Article XIII shall be subject to Section 13.12.

          SECTION 13.02. Liquidation, Dissolution, Bankruptcy. Upon any payment
                         ------------------------------------
or distribution of the assets of the Issuers to creditors upon a voluntary or
involuntary liquidation or

                                       55
<PAGE>

a dissolution of the Issuers or in a bankruptcy, reorganization, insolvency,
receivership or similar proceeding relating to the Issuers or their property:

               (1)  holders of Senior Indebtedness shall be entitled to receive
       payment in full in cash of the Senior Indebtedness (including interest
       (if any), accruing on or after the commencement of a proceeding in
       bankruptcy, whether or not allowed as a claim against the Issuers in such
       bankruptcy proceeding) before Holders of Subordinated Debt Securities
       shall be entitled to receive any payment of principal of, or premium, if
       any, or interest on, the Subordinated Debt Securities; and

               (2)  until the Senior Indebtedness is paid in full, any
       distribution to which Holders of Subordinated Debt Securities would be
       entitled but for this Article XII shall be made to holders of Senior
       Indebtedness as their interests may appear, except that such Holders may
       receive Equity Interests and any debt securities that are subordinated to
       Senior Indebtedness to at least the same extent as the Subordinated Debt
       Securities.

          SECTION 13.03. Default on Senior Indebtedness. The Issuers may not pay
                         ------------------------------
the principal of, or premium, if any, or interest on, the Subordinated Debt
Securities or make any deposit into a defeasance trust or pursuant to Article XI
and may not repurchase, redeem or otherwise retire (except, in the case of
Subordinated Debt Securities that provide for a mandatory sinking fund pursuant
to Section 3.04, by the delivery of Subordinated Debt Securities by the Issuers
to the Trustee pursuant to the first paragraph of Section 3.05) any Debt
Securities (collectively, "pay the Subordinated Debt Securities") if (i) any
principal, premium, interest or any other amount payable in respect of Senior
Indebtedness is not paid within any applicable grace period (including at
maturity) or (ii) any other default on Senior Indebtedness occurs and the
maturity of such Senior Indebtedness is accelerated in accordance with its terms
unless, in either case, (x) the default has been cured or waived and any such
acceleration has been rescinded or (y) such Senior Indebtedness has been paid in
full in cash; provided, however, that the Issuers may pay the Subordinated Debt
Securities without regard to the foregoing if the Issuers and the Trustee
receive written notice approving such payment from the Representative of each
issue of Designated Senior Indebtedness. During the continuance of any default
(other than a default described in clause (i) or (ii) of the preceding sentence)
with respect to any Senior Indebtedness pursuant to which the maturity thereof
may be accelerated immediately without further notice (except such notice as may
be required to effect such acceleration) or the expiration of any applicable
grace periods, the Issuers may not pay the Subordinated Debt Securities for a
period (a "Payment Blockage Period") commencing upon the receipt by the Issuers
and the Trustee of written notice of such default from the Representative of any
Designated Senior Indebtedness specifying an election to effect a Payment
Blockage Period (a "Blockage Notice") and ending 179 days thereafter (or earlier
if such Payment Blockage Period is terminated (i) by written notice to the
Trustee and the Issuers from the Person or Persons who gave such Blockage
Notice, (ii) by repayment in full in cash of such Designated Senior Indebtedness
or (iii) because the default giving rise to such Blockage Notice is no longer
continuing). Notwithstanding the provisions described in the immediately
preceding sentence (but subject to the provisions contained in the first
sentence of this Section 13.03), unless the holders of such Designated Senior
Indebtedness or the Representative of such holders shall have

                                       56
<PAGE>

accelerated the maturity of such Designated Senior Indebtedness, the Issuers may
resume payments on the Subordinated Debt Securities after such Payment Blockage
Period. Not more than one Blockage Notice may be given in any consecutive 360-
day period, irrespective of the number of defaults with respect to any number of
issues of Senior Indebtedness during such period. For purposes of this Section
13.03, no default or event of default which existed or was continuing on the
date of the commencement of any Payment Blockage Period with respect to the
Senior Indebtedness initiating such Payment Blockage Period shall be, or be
made, the basis of the commencement of a subsequent Payment Blockage Period by
the Representative of such Senior Indebtedness, whether or not within a period
of 360 consecutive days, unless such default or event of default shall have been
cured or waived for a period of not less than 90 consecutive days.

          SECTION 13.04. Acceleration of Payment of Debt Securities. If payment
                         ------------------------------------------
of the Subordinated Debt Securities is accelerated because of an Event of
Default, the Issuers or the Trustee shall promptly notify the holders of the
Designated Senior Indebtedness (or their Representatives) of the acceleration.

          SECTION 13.05. When Distribution Must Be Paid Over. If a distribution
                         -----------------------------------
is made to Holders of Subordinated Debt Securities that because of this Article
XIII should not have been made to them, the Holders who receive such
distribution shall hold it in trust for holders of Senior Indebtedness and pay
it over to them as their interests may appear.

          SECTION 13.06. Subrogation. After all Senior Indebtedness is paid in
                         -----------
full and until the Subordinated Debt Securities are paid in full, Holders
thereof shall be subrogated to the rights of holders of Senior Indebtedness to
receive distributions applicable to Senior Indebtedness. A distribution made
under this Article XIII to holders of Senior Indebtedness which otherwise would
have been made to Holders of Subordinated Debt Securities is not, as between the
Issuers and such Holders, a payment by the Issuers on Senior Indebtedness.

          SECTION 13.07. Relative Rights. This Article XIII defines the relative
                         ---------------
rights of Holders of Subordinated Debt Securities and holders of Senior
Indebtedness. Nothing in the Indenture shall:

          (1)  impair, as between the Issuers and Holders of Subordinated Debt
     Securities, the obligation of the Issuers, which is absolute and
     unconditional, to pay principal of, and premium, if any, and interest on,
     the Subordinated Debt Securities in accordance with their terms; or

          (2)  prevent the Trustee or any Holder of Subordinated Debt Securities
     from exercising its available remedies upon an Event of Default, subject to
     the rights of holders of Senior Indebtedness to receive distributions
     otherwise payable to Holders of Subordinated Debt Securities.

          SECTION 13.08. Subordination May Not Be Impaired by Issuers. No right
                         --------------------------------------------
of any holder of Senior Indebtedness to enforce the subordination of the
indebtedness evidenced by

                                       57
<PAGE>

the Subordinated Debt Securities shall be impaired by any act or failure to act
by the Issuers or by their failure to comply with the Indenture.

          SECTION 13.09. Rights of Trustee and Paying Agent. Notwithstanding
                         ----------------------------------
Section 13.03, the Trustee or any paying agent may continue to make payments on
Subordinated Debt Securities and shall not be charged with knowledge of the
existence of facts that would prohibit the making of any such payments unless,
not less than two Business Days prior to the date of such payment, a Responsible
Officer of the Trustee receives notice satisfactory to it that payments may not
be made under this Article XIII. The Issuers, the Registrar, any paying agent, a
Representative or a holder of Senior Indebtedness may give the notice; provided,
however, that, if an issue of Senior Indebtedness has a Representative, only the
Representative may give the notice.

          The Trustee in its individual or any other capacity may hold Senior
Indebtedness with the same rights it would have if it were not Trustee. The
Registrar and any paying agent may do the same with like rights. The Trustee
shall be entitled to all the rights set forth in this Article XIII with respect
to any Senior Indebtedness which may at any time be held by it, to the same
extent as any other holder of Senior Indebtedness; and nothing in Article VII
shall deprive the Trustee of any of its rights as such holder. Nothing in this
Article XIII shall apply to claims of, or payments to, the Trustee under or
pursuant to Section 7.06.

          SECTION 13.10. Distribution or Notice to Representative. Whenever a
                         ----------------------------------------
distribution is to be made or a notice given to holders of Senior Indebtedness,
the distribution may be made and the notice given to their Representative (if
any).

          SECTION 13.11. Article XIII Not to Prevent Defaults or Limit Right to
                         ------------------------------------------------------
Accelerate. The failure to make a payment pursuant to the Debt Securities by
----------
reason of any provision in this Article XIII shall not be construed as
preventing the occurrence of a Default. Nothing in this Article XIII shall have
any effect on the right of the Holders or the Trustee to accelerate the maturity
of the Subordinated Debt Securities.

          SECTION 13.12. Trust Moneys Not Subordinated. Notwithstanding anything
                         -----------------------------
contained herein to the contrary, payments from money or the proceeds of U.S.
Government Obligations held in a defeasance trust or in trust under Article XI
by the Trustee for the payment of principal of, and premium, if any, and
interest on, the Subordinated Debt Securities shall not be subordinated to the
prior payment of any Senior Indebtedness or subject to the restrictions set
forth in this Article XIII, and none of the Holders thereof shall be obligated
to pay over any such amount to the Issuers or any holder of Senior Indebtedness
or any other creditor of the Issuers.

          SECTION 13.13. Trustee Entitled to Rely. Upon any payment or
                         ------------------------
distribution pursuant to this Article XIII, the Trustee and the Holders shall be
entitled to rely (i) upon any order or decree of a court of competent
jurisdiction in which any proceedings of the nature referred to in Section 13.02
are pending, (ii) upon a certificate of the liquidating trustee or agent or
other Person making such payment or distribution to the Trustee or to such
Holders or (iii) upon the Representatives for the holders of Senior Indebtedness
for the purpose of ascertaining the Persons entitled to participate in such
payment or distribution, the holders of the Senior

                                       58
<PAGE>

Indebtedness and other indebtedness of the Issuers, the amount thereof or
payable thereon, the amount or amounts paid or distributed thereon and all other
facts pertinent thereto or to this Article XIII. In the event that the Trustee
determines, in good faith, that evidence is required with respect to the right
of any Person as a holder of Senior Indebtedness to participate in any payment
or distribution pursuant to this Article XIII, the Trustee may request such
Person to furnish evidence to the reasonable satisfaction of the Trustee as to
the amount of Senior Indebtedness held by such Person, the extent to which such
Person is entitled to participate in such payment or distribution and other
facts pertinent to the rights of such Person under this Article XIII, and, if
such evidence is not furnished, the Trustee may defer any payment to such Person
pending judicial determination as to the right of such Person to receive such
payment. The provisions of Sections 7.01 and 7.02 shall be applicable to all
actions or omissions of actions by the Trustee pursuant to this Article XIII.

          SECTION 13.14. Trustee to Effectuate Subordination. Each Holder by
                         -----------------------------------
accepting a Subordinated Debt Security authorizes and directs the Trustee on its
behalf to take such action as may be necessary or appropriate to acknowledge or
effectuate the subordination between the Holders of Subordinated Debt Securities
and the holders of Senior Indebtedness as provided in this Article XIII and
appoints the Trustee as attorney-in-fact for any and all such purposes.

          SECTION 13.15. Trustee Not Fiduciary for Holders of Senior
                         -------------------------------------------
Indebtedness. The Trustee shall not be deemed to owe any fiduciary duty to the
------------
holders of Senior Indebtedness and shall not be liable to any such holders if it
shall mistakenly pay over or distribute to Holders of Subordinated Debt
Securities or the Issuers or any other Person, money or assets to which any
holders of Senior Indebtedness shall be entitled by virtue of this Article XIII
or otherwise.

          SECTION 13.16. Reliance by Holders of Senior Indebtedness on
                         ---------------------------------------------
Subordination Provisions. Each Holder by accepting a Subordinated Debt Security
------------------------
acknowledges and agrees that the foregoing subordination provisions are, and are
intended to be, an inducement and a consideration to each holder of any Senior
Indebtedness, whether such Senior Indebtedness was created or acquired before or
after the issuance of the Subordinated Debt Securities, to acquire and continue
to hold, or to continue to hold, such Senior Indebtedness and such holder of
Senior Indebtedness shall be deemed conclusively to have relied on such
subordination provisions in acquiring and continuing to hold, or in continuing
to hold, such Senior Indebtedness.

                             _____________________

          The Trustee hereby accepts the trusts in the Indenture upon the terms
and conditions herein set forth.

                                       59
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused the Indenture to be
duly signed as of the date first written above.

                                        PLAINS ALL AMERICAN PIPELINE, L.P.

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

                                             By:  PLAINS ALL AMERICAN GP LLC,
                                                  its General Partner

                                             By_______________________________
                                                  Name:
                                                  Title:

                                        FIRST UNION NATIONAL BANK

                                             By_______________________________
                                                  Name:
                                                  Title:

                                       60

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