<PAGE>

                                                                     EXHIBIT 4.1

                                                                  EXECUTION COPY
================================================================================

                             BUCKEYE PARTNERS, L.P.

                                     ISSUER

                                       AND

                                  SUNTRUST BANK

                                     TRUSTEE

                          THIRD SUPPLEMENTAL INDENTURE

                          DATED AS OF OCTOBER 12, 2004

                                       TO

                                    INDENTURE

                            DATED AS OF JULY 10, 2003

                              5.300% NOTES DUE 2014

================================================================================

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>                                                                                                            <C>
ARTICLE 1 Relation to Indenture; Definitions................................................................      1
   SECTION 1.01. Relation to Indenture......................................................................      1
   SECTION 1.02. Definitions................................................................................      1
   SECTION 1.03. General References.........................................................................      1

ARTICLE 2 The Series of Securities..........................................................................      2
   SECTION 2.01. The Form and Title of the Securities.......................................................      2
   SECTION 2.02. Amount.....................................................................................      2
   SECTION 2.03. Stated Maturity............................................................................      2
   SECTION 2.04. Interest and Interest Rates................................................................      2
   SECTION 2.05. Place of Payment...........................................................................      2
   SECTION 2.06. Optional Redemption........................................................................      3
   SECTION 2.07. Defeasance and Discharge; Covenant Defeasance..............................................      3
   SECTION 2.08. Global Securities..........................................................................      3

ARTICLE 3 Events of Default.................................................................................      3
   SECTION 3.01. Additional Event of Default................................................................      3

ARTICLE 4 Covenants.........................................................................................      3
   SECTION 4.01. Additional Covenant........................................................................      3

ARTICLE 5 Miscellaneous.....................................................................................      4
   SECTION 5.01. Certain Trustee Matters....................................................................      4
   SECTION 5.02. Continued Effect...........................................................................      4
   SECTION 5.03. Governing Law..............................................................................      5
   SECTION 5.04. Counterparts...............................................................................      5
</TABLE>

EXHIBITS

Exhibit A: Form of Note

                                                    Third Supplemental Indenture
<PAGE>

      THIRD SUPPLEMENTAL INDENTURE, dated as of October 12, 2004 (this "THIRD
SUPPLEMENTAL INDENTURE"), between BUCKEYE PARTNERS, L.P., a Delaware limited
partnership (the "PARTNERSHIP"), having its principal office at 5 Radnor
Corporate Center, Suite 500, 100 Matsonford Road, Radnor, Pennsylvania 19087,
and SUNTRUST BANK, a Georgia banking corporation ("SUNTRUST"), as trustee under
the Indenture referred to below (in such capacity, the "TRUSTEE").

                           RECITALS OF THE PARTNERSHIP

      WHEREAS, the Partnership and the Trustee have heretofore entered into an
Indenture, dated as of July 10, 2003 (the "ORIGINAL INDENTURE"), as amended and
supplemented by the First Supplemental Indenture thereto dated as of July 10,
2003 (the "FIRST SUPPLEMENTAL INDENTURE") and the Second Supplemental Indenture
thereto dated as of August 19, 2003 (the "SECOND SUPPLEMENTAL INDENTURE") (the
Original Indenture, as supplemented from time to time, including without
limitation pursuant to the First Supplemental Indenture, the Second Supplemental
Indenture and this Third Supplemental Indenture being referred to herein as the
"INDENTURE"); and

      WHEREAS, under the Original Indenture, a new series of Securities may at
any time be established by the Board of Directors of Buckeye Pipe Line Company
LLC, the Partnership's general partner (the "GENERAL PARTNER"), in accordance
with the provisions of the Original Indenture, and the terms of such series may
be established by a supplemental indenture executed by the General Partner on
behalf of the Partnership and by the Trustee; and

      WHEREAS, the Partnership proposes to create under the Indenture a new
series of Securities; and

      WHEREAS, all acts and things necessary to make the Notes (as herein
defined), when executed by the General Partner on behalf of the Partnership and
authenticated and delivered by the Trustee as provided in the Original Indenture
and this Third Supplemental Indenture, the valid and binding obligations of the
Partnership and to make this Third Supplemental Indenture a valid and binding
agreement in accordance with the Original Indenture have been done or performed;

      NOW, THEREFORE, in consideration of the premises, agreements and
obligations set forth herein and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
hereby agree, for the equal and proportionate benefit of all Holders of the
Notes, as follows:

                                   ARTICLE 1
                       RELATION TO INDENTURE; DEFINITIONS

      SECTION 1.01. RELATION TO INDENTURE.

      With respect to the Notes, this Third Supplemental Indenture constitutes
an integral part of the Indenture.

      SECTION 1.02. DEFINITIONS.

      For all purposes of this Third Supplemental Indenture, capitalized terms
used herein and not otherwise defined herein shall have the meanings assigned
thereto in the Original Indenture.

      SECTION 1.03. GENERAL REFERENCES.

      All references in this Third Supplemental Indenture to Articles and
Sections, unless otherwise specified, refer to the corresponding Articles and
Sections of this Third Supplemental Indenture; and the

                                                    Third Supplemental Indenture

<PAGE>

term "herein", "hereof", "hereunder" and any other word of similar import refers
to this Third Supplemental Indenture.

                                   ARTICLE 2
                            THE SERIES OF SECURITIES

      SECTION 2.01. THE FORM AND TITLE OF THE SECURITIES.

      There is hereby established a new series of Securities to be issued under
the Indenture and to be designated as the Partnership's 5.300% Notes due 2014
(the "NOTES"). The Notes shall be substantially in the form attached as Exhibit
A 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 Partnership may deem
appropriate or as may be required or appropriate to comply with any laws or with
any rules made pursuant thereto or with the rules of any securities exchange or
automated quotation system on which the Notes may be listed or traded, or to
conform to general usage, or as may, consistently with the Indenture, be
determined by the officers executing such Notes, as evidenced by their execution
thereof.

      The Notes shall be executed, authenticated and delivered in accordance
with the provisions of, and shall in all respects be subject to, the terms,
conditions and covenants of the Original Indenture as supplemented by this Third
Supplemental Indenture (including the form of Note set forth as Exhibit A hereto
(the terms of which are incorporated in and made a part of this Third
Supplemental Indenture for all intents and purposes)).

      SECTION 2.02. AMOUNT.

      The aggregate principal amount of the Notes which may be authenticated and
delivered pursuant hereto is unlimited. The Trustee shall initially authenticate
and deliver Notes for original issue in an initial aggregate principal amount of
up to $275,000,000 upon delivery to the Trustee of a Partnership Order for the
authentication and delivery of such Notes. The aggregate principal amount of the
Notes to be issued hereunder may be increased at any time hereafter and the
series may be reopened for issuances of additional Notes, upon Partnership Order
without the consent of any Holder. The Notes issued on the date hereof and any
such additional Notes that may be issued hereafter shall be part of the same
series of Securities for all purposes under the Indenture.

      SECTION 2.03. STATED MATURITY.

      The Notes may be issued on any Business Day on or after October 12, 2004,
and the Stated Maturity of the Notes shall be October 15, 2014.

      SECTION 2.04. INTEREST AND INTEREST RATES.

      The rate or rates at which the Notes shall bear interest, the date or
dates from which such interest shall accrue, the Interest Payment Dates on which
any such interest shall be payable and the Regular Record Date for any interest
payable on any Interest Payment Date, in each case, shall be as set forth in the
form of Note set forth as Exhibit A hereto.

      SECTION 2.05. PLACE OF PAYMENT.

      As long as any Notes are outstanding, the Partnership shall maintain an
office or agency in the Borough of Manhattan, The City of New York, where Notes
may be presented for payment.

                                                    Third Supplemental Indenture

                                       2
<PAGE>

      SECTION 2.06. OPTIONAL REDEMPTION.

      At its option, the Partnership may redeem the Notes, in whole or in part,
in principal amounts of $1,000 or any integral multiple thereof, at any time or
from time to time, at the applicable redemption price determined as set forth in
the form of Note attached hereto as Exhibit A, in accordance with the terms set
forth in the Notes and in accordance with Article XI of the Original Indenture.

      SECTION 2.07. DEFEASANCE AND DISCHARGE; COVENANT DEFEASANCE.

      Article XIII of the Original Indenture shall apply to the Notes.

      SECTION 2.08. GLOBAL SECURITIES.

      The Notes shall initially be issuable in whole or in part in the form of
one or more Global Securities. Such Global Securities (i) shall be deposited
with, or on behalf of, the Depository Trust Company, New York, New York, which
shall act as Depositary with respect to the Notes, (ii) shall bear the legends
applicable to Global Securities set forth in Sections 2.02 and 2.04 of the
Original Indenture, (iii) may be exchanged in whole or in part for Securities in
definitive form upon the terms and subject to the conditions provided in Section
3.05 of the Original Indenture and in this Third Supplemental Indenture and (iv)
shall otherwise be subject to the applicable provisions of the Indenture.

                                   ARTICLE 3
                                EVENTS OF DEFAULT

      SECTION 3.01. ADDITIONAL EVENT OF DEFAULT

      With respect to the Notes, the occurrence of any of the following events
shall, in addition to the other events or circumstances described as Events of
Default in Section 5.01 of the Original Indenture, constitute an Event of
Default: default under any mortgage, indenture or instrument under which there
may be issued or by which there may be secured or evidenced any Indebtedness of
the Partnership or any of its Subsidiaries (or the payment of which is
guaranteed by the Partnership or any of its Subsidiaries), whether such
Indebtedness or guarantee now exists or is created after the date of issuance of
any Notes, if (a) that default (x) is caused by a failure to pay principal of or
premium, if any, or interest on such Indebtedness prior to the expiration of any
grace period provided in such Indebtedness (a "PAYMENT DEFAULT"), or (y) results
in the acceleration of the maturity of such Indebtedness to a date prior to its
originally stated maturity, and, (b) in each case described in clauses (x) or
(y) above, the principal amount of any such Indebtedness, together with the
principal amount of any other such Indebtedness under which there has been a
Payment Default or the maturity of which has been so accelerated, aggregates
$50,000,000 or more.

                                    ARTICLE 4
                                    COVENANTS

      SECTION 4.01. ADDITIONAL COVENANT

      The covenant contained in this Section 4.01 shall apply to the Notes only
and not to any other series of Securities issued under the Indenture, and is
being included solely for the benefit of the Notes and the Holders thereof. This
covenant shall be effective only for so long as there remain Outstanding any
Notes.

      SEC Reports; Financial Statements.

            (1)   Whether or not the Partnership is then subject to the
      reporting requirements of Section 13 or 15(d) of the Exchange Act, from
      and after the Issue Date of the Notes, the

                                                    Third Supplemental Indenture

                                       3
<PAGE>

      Partnership shall electronically file with the Commission, so long as the
      Notes are Outstanding, the annual, quarterly and other periodic reports
      that the Partnership is required to file (or would otherwise be required
      to file) with the Commission pursuant to Sections 13 and 15(d) of the
      Exchange Act, and such documents shall be filed with the Commission on or
      prior to the respective dates (the "REQUIRED FILING DATES") by which the
      Partnership is required to file (or would otherwise be required to file)
      such documents, unless, in each case, such filings are not then permitted
      by the Commission.

            (2)   If such filings are not then permitted by the Commission, or
      such filings are not generally available on the Internet free of charge,
      from and after the Issue Date of the Notes, the Partnership shall provide
      the Trustee with, and the Trustee, at the Partnership's expense, will mail
      to any Holder of Notes requesting in writing to the Trustee copies of,
      such annual, quarterly and other periodic report specified in Sections 13
      and 15(d) of the Exchange Act within 15 days after its Required Filing
      Date; provided, however, the Trustee shall have no liability whatsoever
      with respect to the mailing and delivery of such reports to the Holders.

            (3)   The Partnership shall provide the Trustee with a sufficient
      number of copies of all reports and other documents and information that
      the Trustee may be required to deliver to Holders of Notes under clause
      (2) of this Section 4.01, along with written notice from the Partnership
      to the Trustee of the Required Filing Date for such documents.

            (4)   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 constructive notice of any information contained
      therein or determinable from information contained therein, including the
      Partnership's compliance with any of its covenants hereunder (as to which
      the Trustee is entitled to rely exclusively on Officers' Certificates).

                                   ARTICLE 5
                                  MISCELLANEOUS

      SECTION 5.01. CERTAIN TRUSTEE MATTERS.

      The recitals contained herein shall be taken as the statements of the
Partnership, and the Trustee assumes no responsibility for their correctness.

      The Trustee makes no representations as to the validity or sufficiency of
this Third Supplemental Indenture or the Notes or the proper authorization or
the due execution hereof or thereof by the Partnership.

      Except as expressly set forth herein, nothing in this Third Supplemental
Indenture shall alter the duties, rights or obligations of the Trustee set forth
in the Original Indenture.

      The Trustee makes no representation or warranty as to the validity or
sufficiency of the information contained in the prospectus supplement related to
the Notes, except such information which specifically pertains to the Trustee
itself, or any information incorporated therein by reference.

      SECTION 5.02. CONTINUED EFFECT.

      Except as expressly supplemented and amended by this Third Supplemental
Indenture, the Original Indenture (as supplemented and amended by the First
Supplemental Indenture and the Second Supplemental Indenture) shall continue in
full force and effect in accordance with the provisions thereof, and the
Original Indenture (as supplemented and amended by the First Supplemental
Indenture, the Second Supplemental Indenture and this Third Supplemental
Indenture) is in all respects hereby ratified

                                                    Third Supplemental Indenture

                                       4
<PAGE>

and confirmed. This Third Supplemental Indenture and all its provisions shall be
deemed a part of the Original Indenture in the manner and to the extent herein
and therein provided.

      SECTION 5.03. GOVERNING LAW.

      This Third Supplemental Indenture and the Notes shall be governed by and
construed in accordance with the laws of the State of New York.

      SECTION 5.04. COUNTERPARTS.

      This instrument may be executed in any number of counterparts, each of
which shall be deemed to be an original, but all such counterparts shall
together constitute but one and the same instrument.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                                    Third Supplemental Indenture

                                       5
<PAGE>

      IN WITNESS WHEREOF, the parties hereto have caused this Third Supplemental
Indenture to be duly executed and delivered, all as of the day and year first
above written.

                                   BUCKEYE PARTNERS, L.P.

                                   By: BUCKEYE PIPE LINE COMPANY LLC
                                       Its General Partner

                                   By: /s/ Stephen C. Muther
                                       ________________________________________
                                   Name:  Stephen C. Muther
                                   Title: Senior Vice President --
                                          Administration, General Counsel
                                          and Secretary



                                   SUNTRUST BANK,
                                   as Trustee

                                   By: /s/ Jack Ellerin
                                       _______________________________________
                                   Name:  Jack Ellerin
                                   Title: Authorized Officer

                                                    Third Supplemental Indenture

<PAGE>

                                                                       EXHIBIT A

                             [FORM OF FACE OF NOTE]

[IF A GLOBAL SECURITY, INSERT -- THIS SECURITY IS A GLOBAL SECURITY WITHIN THE
MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME
OF A DEPOSITARY OR A NOMINEE THEREOF. THIS SECURITY MAY NOT BE TRANSFERRED TO,
OR REGISTERED OR EXCHANGED FOR SECURITIES REGISTERED IN THE NAME OF, ANY PERSON
OTHER THAN THE DEPOSITARY OR A NOMINEE THEREOF AND NO SUCH TRANSFER MAY BE
REGISTERED, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.
EVERY SECURITY AUTHENTICATED AND DELIVERED UPON REGISTRATION OF TRANSFER OF, OR
IN EXCHANGE FOR OR IN LIEU OF, THIS SECURITY SHALL BE A GLOBAL SECURITY SUBJECT
TO THE FOREGOING, EXCEPT IN SUCH LIMITED CIRCUMSTANCES.]

[IF A GLOBAL SECURITY, INSERT -- UNLESS THIS SECURITY IS PRESENTED BY AN
AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK
CORPORATION, TO THE PARTNERSHIP OR ITS AGENT FOR REGISTRATION OF TRANSFER,
EXCHANGE OR PAYMENT, AND ANY SECURITY ISSUED IS REGISTERED IN THE NAME OF CEDE &
CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER
ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST
COMPANY), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO.,
HAS AN INTEREST HEREIN.]

                             BUCKEYE PARTNERS, L.P.

                              5.300% NOTE DUE 2014

No. _________                                                U.S.$_____________

CUSIP No. ___________

      BUCKEYE PARTNERS, L.P., a Delaware limited partnership (herein called the
"Partnership", which term includes any successor Person under the Indenture
hereinafter referred to), for value received, hereby promises to pay to
____________________, or registered assigns, the principal sum of
_____________________________ United States Dollars on October 15, 2014, and to
pay interest thereon from October 12, 2004, or from the most recent Interest
Payment Date to which interest has been paid or duly provided for, semi-annually
on April 15 and October 15 in each year, commencing on April 15, 2005, at the
rate of 5.300% per annum, until the principal hereof is paid or made available
for payment and at the rate of 5.300% per annum on any overdue principal and
premium and on any overdue installment of interest. The amount of interest
payable for any period shall be computed on the basis of twelve 30-day months
and a 360-day year. The amount of interest payable for any partial period shall
be computed on the basis of a 360-day year of twelve 30-day months and the days
elapsed in any partial month. In the event that any date on which interest is
payable on this Security is not a Business Day, then a payment of the interest
payable on such date will be made on the next succeeding day which is a Business
Day (and without any interest or other payment in respect of any such delay)
with the same force and effect as if made on the date the payment was originally
payable. A "Business Day" shall mean, when used with respect to any Place of
Payment, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day
on which banking institutions in that Place of Payment are authorized or
obligated by law, executive order or regulation to close. The interest so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in such Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on the "Regular Record Date" for such interest, which shall be the
April 1 or October 1 (whether or not a Business Day), as the case may be, next
preceding such Interest Payment Date. Any such interest not so punctually paid
or duly provided for shall forthwith cease to be payable to the Holder on such
Regular Record Date and may either be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on a Special Record Date for the payment of such Defaulted Interest to
be fixed by the Trustee, notice of which shall be given to Holders of Securities
of this series not less than 10 days prior to such Special Record Date, or be
paid at any time in any other lawful manner not inconsistent with the
requirements of any securities exchange or automated quotation system on which
the Securities of this series may be listed or traded, and upon such notice as
may be required by such exchange or automated quotation system, all as more
fully provided in such Indenture.

                                                    Third Supplemental Indenture

                                       A-1
<PAGE>

      [If a Global Security, insert -- Payment of the principal of (and premium,
if any) and any such interest on this Security will be made by transfer of
immediately available funds to a bank account in the United States of America
designated by the Holder in such coin or currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts.]

      [If a Definitive Security, insert -- Payment of the principal of (and
premium, if any) and any such interest on this Security will be made at the
office or agency of the Partnership maintained for that purpose in the Borough
of Manhattan, the City and State of New York, in such coin or currency of the
United States of America as at the time of payment is legal tender for payment
of public and private debts or subject to any laws or regulations applicable
thereto and to the right of the Partnership (as provided in the Indenture) to
rescind the designation of any such Paying Agent, at the offices of
_________________ in the Borough of Manhattan, The City and State of New York,
and at such other offices or agencies as the Partnership may designate, by
United States Dollar check drawn on, or transfer to a United States Dollar
account maintained by the payee with, a bank in The City of New York (so long as
the applicable Paying Agent has received proper transfer instructions in writing
at least 10 days prior to the payment date); provided, however, that payment of
interest may be made at the option of the Partnership by United States Dollar
check mailed to the addresses of the Persons entitled thereto as such addresses
shall appear in the Security Register or by transfer to a United States Dollar
account maintained by the payee with a bank in The City of New York (so long as
the applicable Paying Agent has received proper transfer instructions in writing
by the Record Date prior to the applicable Interest Payment Date).]

      Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

      IN WITNESS WHEREOF, the Partnership has caused this instrument to be duly
      executed.

Dated:  ______________, ____

                                   BUCKEYE PARTNERS, L.P.

                                   By: BUCKEYE PIPE LINE COMPANY LLC
                                       its General Partner

                                       By: ___________________________________
                                       Name:
                                       Title:

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

SUNTRUST BANK,
as Trustee

By: _______________________________
         Authorized Signatory

                                                    Third Supplemental Indenture

                                       A-2
<PAGE>

                                [REVERSE OF NOTE]

                             BUCKEYE PARTNERS, L.P.

                              5.300% NOTE DUE 2014

      This Security is one of a duly authorized issue of securities of the
Partnership (the "Securities"), issued and to be issued in one or more series
under an Indenture dated as of July 10, 2003, as amended and supplemented by the
First Supplemental Indenture thereto dated as of July 10, 2003, as further
amended and supplemented by the Second Supplemental Indenture thereto dated as
of August 19, 2003 and as further amended and supplemented by the Third
Supplemental Indenture thereto dated as of October 12, 2004 (such Indenture, as
so amended and supplemented being referred to herein as the "Indenture"),
between the Partnership and SunTrust Bank, a Georgia banking corporation, as
Trustee (the "Trustee," which term includes any successor trustee under the
Indenture), to which Indenture and all indentures supplemental thereto reference
is hereby made for a statement of the respective rights, limitations of rights,
obligations, duties and immunities thereunder of the Partnership, the Trustee
and the Holders of the Securities and of the terms upon which the Securities
are, and are to be, authenticated and delivered. This Security is one of the
series designated on the face hereof.

      This Security is redeemable, in whole or in part, at the Partnership's
option at any time prior to maturity at a redemption price equal to the greater
of (a) 100% of the principal amount of this Security, and (b) as determined by
the Quotation Agent (as defined below), the sum of the present values of the
remaining scheduled payments of principal and interest (not including any
portion of those payments of interest accrued as of the date of redemption)
discounted to the date of redemption on a semi-annual basis (assuming a 360-day
year consisting of twelve 30-day months) at the Adjusted Treasury Rate (as
defined below) plus 20 basis points, plus, in each case, accrued and unpaid
interest to the date of redemption.

      For purposes of determining any redemption price, the following
definitions shall apply:

      "Adjusted Treasury Rate" means, with respect to any date of redemption,
the rate per annum equal to the semi-annual equivalent yield to maturity of the
Comparable Treasury Issue (as defined below), assuming a price for the
Comparable Treasury Issue (expressed as a percentage of its principal amount)
equal to the Comparable Treasury Price (as defined below) for the date of
redemption.

      "Comparable Treasury Issue" means the United States Treasury security
selected by the Quotation Agent as having a maturity comparable to the remaining
term of this Security that would be utilized, at the time of selection and in
accordance with customary financial practice, in pricing new issues of corporate
debt securities of comparable maturity to the remaining term of this Security.

      "Comparable Treasury Price" means, with respect to any date of redemption,
(a) the average of the Reference Treasury Dealer Quotations (as defined below)
for the date of redemption, after excluding the highest and lowest Reference
Treasury Dealer Quotations, or (b) if the Trustee obtains fewer than three
Reference Treasury Dealer Quotations, the average of all such Reference Treasury
Dealer Quotations.

      "Quotation Agent" means Goldman, Sachs & Co. or another Reference Treasury
Dealer (as defined below) appointed by the Partnership.

      "Reference Treasury Dealer" means (a) each of Goldman, Sachs & Co. and its
respective successors; provided, however, that if any of the foregoing shall
cease to be a primary U.S. Government securities dealer in New York City (a
"Primary Treasury Dealer"), the Partnership shall substitute another Primary
Treasury Dealer; and (b) any other Primary Treasury Dealer selected by the
Partnership.

      "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any date of redemption, the average, as determined
by the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by that Reference Treasury Dealer at 5:00 p.m., New York
City time, on the third business day preceding that date of redemption.

      Unless the Partnership defaults in payment of the redemption price, on and
after the date of redemption, interest will cease to accrue on this Security or
the portions hereof called for redemption.

                                                    Third Supplemental Indenture

                                       A-3
<PAGE>

      In the event of redemption of this Security in part only, a new Security
or Securities of this series and of like tenor for the unredeemed portion hereof
will be issued in the name of the Holder hereof upon the cancellation hereof.

      The Indenture contains provisions for defeasance at any time of (1) the
entire indebtedness of this Security or (2) certain restrictive covenants and
Events of Default with respect to this Security, in each case upon compliance
with certain conditions set forth in the Indenture.

      If an Event of Default with respect to Securities of this series shall
occur and be continuing, the principal of the Securities of this series may be
declared due and payable in the manner and with the effect provided in the
Indenture.

      The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Partnership and the rights of the Holders of the Securities of each series to be
affected under the Indenture at any time by the Partnership and the Trustee with
the consent of not less than the Holders of a majority in aggregate principal
amount of the Outstanding Securities of all series to be affected (voting as one
class). The Indenture also contains provisions permitting the Holders of a
majority in aggregate principal amount of the Outstanding Securities of all
affected series (voting as one class), on behalf of the Holders of all
Securities of such series, to waive compliance by the Partnership with certain
provisions of the Indenture. The Indenture permits, with certain exceptions as
therein provided, the Holders of a majority in principal amount of Securities of
any series then Outstanding to waive past defaults under the Indenture with
respect to such series and their consequences. Any such consent or waiver by the
Holder of this Security shall be conclusive and binding upon such Holder and all
holders of Securities of which this Security is a Predecessor Security, whether
or not notation of such consent or waiver is made upon this or any other
Security.

      As provided in and subject to the provisions of the Indenture, the Holder
of this Security shall not have the right to institute any proceeding with
respect to the Indenture or for the appointment of a receiver or trustee or for
any other remedy thereunder, unless such Holder shall have previously given the
Trustee written notice of a continuing Event of Default with respect to the
Securities of this series, the Holders of not less than a majority in principal
amount of the Securities of this series at the time Outstanding shall have made
written request to the Trustee to institute proceedings in respect of such Event
of Default as Trustee and offered the Trustee indemnity satisfactory to the
Trustee and the Trustee shall not have received from the Holders of a majority
in principal amount of Securities of this series at the time Outstanding a
direction inconsistent with such request, and shall have failed to institute any
such proceeding, for 60 days after receipt of such notice, request and offer of
indemnity. The foregoing shall not apply to any suit instituted by the Holder of
this Security for the enforcement of any payment of principal hereof or any
premium or interest hereon on or after the respective due dates expressed
herein.

      No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Partnership, which
is absolute and unconditional, to pay the principal of and any premium and
interest on this Security at the times, place(s) and rate, and in the coin or
currency, herein prescribed.

      [If a Global Security, insert -- This Global Security or portion hereof
may not be exchanged for Definitive Securities of this series except in the
limited circumstances provided in the Indenture.

      The holders of beneficial interests in this Global Security will not be
entitled to receive physical delivery of Definitive Securities except as
described in the Indenture and will not be considered the Holders thereof for
any purpose under the Indenture.]

      [If a Definitive Security, insert -- As provided in the Indenture and
subject to certain limitations therein set forth, the transfer of this Security
is registerable in the Security Register, upon surrender of this Security for
registration of transfer at the office or agency of the Partnership in The City
of New York, or, subject to any laws or regulations applicable thereto and to
the right of the Partnership (limited as provided in the Indenture) to rescind
the designation of any such transfer agent, at the offices of _________________
in the Borough of Manhattan, The City of New York, and at such other offices or
agencies as the Partnership may designate, duly endorsed by, or accompanied by a
written instrument of transfer in form satisfactory to the Partnership and the
Security Registrar duly executed by, the Holder hereof or his attorney duly
authorized in writing, and thereupon one or more new Securities of this series
and of like tenor, of authorized denominations and for the same aggregate
principal amount, will be issued to the designated transferee or transferees.]

                                                    Third Supplemental Indenture

                                       A-4
<PAGE>

      The Securities of this series are issuable only in registered form without
coupons in denominations of $1,000 and any integral multiple thereof. As
provided in the Indenture and subject to certain limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal amount
of Securities of this series and of like tenor of a different authorized
denomination, as requested by the Holder surrendering the same.

      No service charge shall be made for any such registration of transfer or
exchange, but the Partnership may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

      Prior to due presentment of this Security for registration of transfer,
the Partnership, the Trustee and any agent of the Partnership or the Trustee may
treat the Person in whose name this Security is registered as the owner hereof
for all purposes, whether or not this Security is overdue, and neither the
Partnership, the Trustee nor any such agent shall be affected by notice to the
contrary.

      Obligations of the Partnership under the Indenture and the Securities
thereunder, including this Security, are non-recourse to Buckeye Pipe Line
Company LLC (the "General Partner") and its Affiliates (other than the
Partnership), and payable only out of cash flow and assets of the Partnership.
The Trustee, and each Holder of a Security by its acceptance hereof, will be
deemed to have agreed in the Indenture that (1) neither the General Partner nor
its assets (nor any of its Affiliates, other than the Partnership, or their
respective assets) shall be liable for any of the obligations of the Partnership
under the Indenture or such Securities, including this Security, and (2) no
director, officer, employee, stockholder or unitholder, as such, of the
Partnership, the Trustee, the General Partner or any Affiliate of any of the
foregoing entities shall have any personal liability in respect of the
obligations of the Partnership under the Indenture or such Securities by reason
of his, her or its status.

      This Security shall be governed by and construed in accordance with the
laws of the State of New York.

      All terms used in this Security which are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

                                                    Third Supplemental Indenture

                                       A-5
<PAGE>

      [If a Definitive Security, insert as a separate page--

      FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s) and
transfer(s) unto _____________________________________ (Please Print or
Typewrite Name and Address of Assignee) the within instrument of BUCKEYE
PARTNERS, L.P. and does hereby irrevocably constitute and appoint
________________________ Attorney to transfer said instrument on the books of
the within-named Partnership, with full power of substitution in the premises.

Please Insert Social Security or
Other Identifying Number of Assignee:

___________________________________   ___________________________________

Dated: ____________________________   ___________________________________
                                      (Signature)

Signature Guarantee: ____________________________________________________
                     (Participant in a Recognized Signature
                           Guaranty Medallion Program)

      NOTICE: The signature to this assignment must correspond with the name as
written upon the face of the within instrument in every particular, without
alteration or enlargement or any change whatever.]

                                                    Third Supplemental Indenture

                                      A-6
<PAGE>

      [If a Global Security, insert as a separate page--

                       SCHEDULE OF INCREASES OR DECREASES
                               IN GLOBAL SECURITY

      The following increases or decreases in this Global Security have been
made:

<TABLE>
<CAPTION>
                     AMOUNT OF                            PRINCIPAL AMOUNT OF
                    DECREASE IN     AMOUNT OF INCREASE   THIS GLOBAL SECURITY     SIGNATURE OF
                  PRINCIPAL AMOUNT  IN PRINCIPAL AMOUNT     FOLLOWING SUCH     AUTHORIZED OFFICER
                  OF THIS GLOBAL          OF THIS              DECREASE          OF TRUSTEE OR
DATE OF EXCHANGE      SECURITY        GLOBAL SECURITY       (OR INCREASE)         DEPOSITARY]
----------------  ----------------  -------------------  --------------------  -----------------
<S>               <C>               <C>                  <C>                   <C>
</TABLE>

                                                    Third Supplemental Indenture

                                      A-7