Exhibit 4.1

Execution Version

REGISTRATION RIGHTS AGREEMENT

BY AND AMONG

BUCKEYE PARTNERS, L.P.

AND

THE INVESTORS NAMED ON SCHEDULE A HERETO

TABLE OF CONTENTS

Schedule A – Investor List; Notice and Contact Information; Opt-Out

Exhibit A – Form of Joinder Agreement

REGISTRATION RIGHTS AGREEMENT

This REGISTRATION RIGHTS AGREEMENT (this “ Agreement ”) is made and entered into as of March 2, 2018, by and among Buckeye Partners, L.P., a Delaware limited partnership (the “ Partnership ”), and each of the Persons set forth on Schedule A to this Agreement and each Person who has executed a Joinder Agreement pursuant to Section 3.03 hereof (each, an “ Investor ” and collectively, the “ Investors ”).

WHEREAS, this Agreement is made in connection with the entry into the Class C Unit Purchase Agreement, dated on or prior to the date hereof, by and among the Partnership and each of the Persons set forth on Schedule A thereto, providing for the issuance of Class C Units (the “ Unit Purchase Agreement ”); and

WHEREAS, the Partnership has agreed to provide the registration and other rights set forth in this Agreement for the benefit of the Investors pursuant to the Unit Purchase Agreement.

NOW THEREFORE, in consideration of the mutual covenants and agreements set forth herein and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each party hereto, the parties hereby agree as follows:

ARTICLE I

DEFINITIONS

Section 1.01 Definitions . Capitalized terms used herein without definition shall have the meanings given to them in the Unit Purchase Agreement. The terms set forth below are used herein as so defined:

“ Affiliate ” means, with respect to any Person, any other Person that directly or indirectly through one or more intermediaries controls, is controlled by or is under common control with, the Person in question. As used herein, the term “control” means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through ownership of voting securities, by contract or otherwise.

“ Agreement ” has the meaning specified therefor in the introductory paragraph of this Agreement.

“ Class  C Unit Price ” means $42.60.

“ Commission ” means the U.S. Securities and Exchange Commission.

“ Effectiveness Period ” has the meaning specified therefor in Section  2.01(a) of this Agreement.

“ First Registration Statement ” has the meaning specified therefor in Section  2.01(a) of this Agreement.

“ General Partner ” means Buckeye GP LLC, a Delaware limited liability company.

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“ Holder ” means the record holder of any Registrable Securities.

“ Included Registrable Securities ” has the meaning specified therefor in Section  2.02(a) of this Agreement.

“ Investor ” and “ Investors ” have the meanings specified therefor in the introductory paragraph of this Agreement.

“ Liquidated Damages ” has the meaning specified therefor in Section  2.01(b) of this Agreement.

“ Liquidated Damages Multiplier ” means the product of the Class C Unit Price times the number of Purchased Units issued to such Investor and that may not be disposed of without restriction pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act.

“ Losses ” has the meaning specified therefor in Section  2.09(a) of this Agreement.

“ Managing Underwriter ” means, with respect to any Underwritten Offering, the book-running lead manager or managers of such Underwritten Offering.

“ Opt-Out Notice ” has the meaning specified therefor in Section  2.02(a) of this Agreement.

“ Parity Securities ” has the meaning specified therefor in Section  2.02(b) of this Agreement.

“ Partnership ” has the meaning specified therefor in the introductory paragraph of this Agreement.

“ Person ” means an individual or a corporation, limited liability company, partnership, joint venture, trust, unincorporated organization, association, government agency or political subdivision thereof or other entity.

“ PIK Registrable Securities ” has the meaning specified therefor in Section  2.01(a) of this Agreement.

“ PIK Registration Statement ” has the has the meaning specified therefor in Section  2.01(a) of this Agreement.

“ Purchased Units ” has the meaning specified for “Purchased Units” in the Unit Purchase Agreement.

“ Registrable Securities ” means (i) LP Units issued upon the conversion of the Class C Units and (ii) any LP Units issued as Liquidated Damages pursuant to Section  2.01(b) of this Agreement, in each case, as subject to exchange, substitution or adjustment pursuant to Section 3.04 of this Agreement, all of which Registrable Securities are subject to the rights provided herein until such rights terminate pursuant to the provisions hereof.

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“ Registration Expenses ” has the meaning specified therefor in Section  2.08(b) of this Agreement.

“ Registration Statement ” has the meaning specified therefor in Section  2.01(a) of this Agreement.

“ Selling Expenses ” has the meaning specified therefor in Section  2.08(b) of this Agreement.

“ Selling Holder ” means a Holder who is selling Registrable Securities pursuant to a registration statement.

“ Selling Holder Indemnified Persons ” has the meaning specified therefor in Section  2.09(a) of this Agreement.

“ Underwritten Offering ” means an offering (including an offering pursuant to a Registration Statement) in which LP Units are sold to an underwriter on a firm commitment basis for reoffering to the public or an offering that is a “bought deal” with one or more investment banks.

“ Unit Purchase Agreement ” has the meaning specified therefor in the recitals of this Agreement.

Section 1.02 Registrable Securities . Any Registrable Security will cease to be a Registrable Security (a) when a registration statement covering such Registrable Security becomes or has been declared effective by the Commission and such Registrable Security has been sold or disposed of pursuant to such effective registration statement; (b) when such Registrable Security has been disposed of pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act; (c) when such Registrable Security is held by the Partnership or one of its subsidiaries or Affiliates; (d) when such Registrable Security has been sold or disposed of in a private transaction in which the transferor’s rights under this Agreement are not assigned to the transferee of such securities pursuant to Section 2.11 hereof or (e) two years following their issuance as LP Units, including the issuance of LP Units as Liquidated Damages and the issuance of LP Units upon conversion of Class C Units.

ARTICLE II

REGISTRATION RIGHTS

Section 2.01 Registration .

(a) Effectiveness Deadline . Following the date hereof, but no later than ninety (90) days prior to the first to occur of (i) the second anniversary of the Closing Date and (ii) the date that any Class C Units are otherwise converted into LP Units (the “ Registration Date ”), the Partnership shall prepare and file a registration statement (the “ First Registration Statement ”) under the Securities Act with respect to all of the Registrable Securities other than, if applicable, (x) any Registrable Securities issuable upon conversion of any Class C Units issued as a distribution in kind in lieu of cash distributions after the Registration Date (the “ PIK Registrable Securities ”) and (y) any LP Units issued as Liquidated Damages. No later than ninety (90) days

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following the distribution of any PIK Registrable Securities following the filing of the First Registration Statement, if applicable, the Partnership shall prepare and file a registration statement or registration statements, if applicable (collectively, the “ PIK Registration Statement ” and, together with the First Registration Statement, the “ Registration Statements ”) under the Securities Act or a post-effective amendment to the First Registration Statement with respect to such PIK Registrable Securities. The Registration Statements filed pursuant to this Section  2.01(a) shall be on such appropriate registration form of the Commission as shall be selected by the Partnership. The Partnership shall use its commercially reasonable efforts to cause the Registration Statements to become effective on or as soon as practicable after the date on which they are filed. Any Registration Statement shall provide for the resale pursuant to any method or combination of methods legally available to, and requested by, the Holders of any and all Registrable Securities covered by such Registration Statements. The Partnership shall use its commercially reasonable efforts to cause the Registration Statements filed pursuant to this Section  2.01(a) to be effective, supplemented and amended to the extent necessary to ensure that it is available for the resale of all Registrable Securities by the Holders until all Registrable Securities covered by such Registration Statements have ceased to be Registrable Securities (the “ Effectiveness Period ”). The Registration Statements when effective (including the documents incorporated therein by reference) will comply as to form in all material respects with all applicable requirements of the Securities Act and the Exchange Act and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading (in the case of any prospectus contained in such Registration Statements, in the light of the circumstances under which a statement is made). As soon as practicable following the date that each Registration Statement becomes effective, but in any event within two (2) Business Days of such date, the Partnership shall provide the Holders with written notice of the effectiveness of such Registration Statement.

(b) Failure to Go Effective . If each of the Registration Statements required by Section  2.01(a) are not declared effective within ninety (90) days after the date such Registration Statement is filed, then each Holder shall be entitled to a payment (with respect to the Purchased Units of each such Holder), as liquidated damages and not as a penalty, of 0.25% of the Liquidated Damages Multiplier per thirty (30)-day period, that shall accrue daily, for the first sixty (60) days following the 90th day, increasing by an additional 0.25% of the Liquidated Damages Multiplier per thirty (30)-day period, that shall accrue daily, for each subsequent thirty (30) days, up to a maximum of 1.00% of the Liquidated Damages Multiplier per thirty (30)-day period (the “ Liquidated Damages ”); provided, however , the aggregate amount of Liquidated Damages payable by the Partnership under this Agreement to each Holder shall not exceed 5.00% of the Liquidated Damages Multiplier with respect to such Holder. The Liquidated Damages payable pursuant to the immediately preceding sentence shall be payable within ten (10) Business Days after the end of each such thirty (30)-day period. Any Liquidated Damages shall be paid to each Holder in immediately available funds; provided , however , if the Partnership certifies that it is unable to pay Liquidated Damages in cash because such payment would result in a breach under a credit facility or other debt instrument, then the Partnership may pay the Liquidated Damages in kind in the form of the issuance of additional LP Units. Upon any issuance of LP Units as Liquidated Damages, the Partnership shall promptly (i) prepare and file an amendment to the applicable Registration Statement prior to its effectiveness adding such LP Units to such Registration Statement as additional Registrable Securities and (ii) prepare and file a supplemental listing application with the NYSE to list such additional LP Units. The

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determination of the number of LP Units to be issued as Liquidated Damages shall be equal to the amount of Liquidated Damages divided by the volume-weighted average closing price of the LP Units on the NYSE for the ten (10) trading days immediately preceding the date on which the Liquidated Damages payment is due, less a discount to such average closing price of 2.00%. The payment of Liquidated Damages to a Holder shall cease at the earlier of (i) the applicable Registration Statement becoming effective or (ii) the Purchased Units of such Holder becoming eligible for resale without restriction under any section of Rule 144 (or any similar provision then in effect) under the Securities Act, assuming that each Holder is not an Affiliate of the Partnership, and any payment of Liquidated Damages shall be prorated for any period of less than thirty (30) days in which the payment of Liquidated Damages ceases. If the Partnership is unable to cause the applicable Registration Statement to go effective within ninety (90) days after the date of its filing as a result of an acquisition, merger, reorganization, disposition, financing or other similar transaction, then the Partnership may request a waiver of the Liquidated Damages, and each Holder may individually grant or withhold its consent to such request in its discretion.

Section 2.02 Piggyback Rights .

(a) Participation . In the event the Registrable Securities may not be disposed of without restriction pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act, if the Partnership proposes to file (i) a shelf registration statement other than the Registration Statements contemplated by Section  2.01(a) , (ii) a prospectus supplement to an effective shelf registration statement, other than the Registration Statements contemplated by Section  2.01(a) of this Agreement and Holders may be included without the filing of a post-effective amendment thereto, or (iii) a registration statement, other than a shelf registration statement, in each case, for the sale of LP Units in an Underwritten Offering for its own account and/or another Person, then as soon as practicable following the engagement of counsel by the Partnership to prepare the documents to be used in connection with an Underwritten Offering, the Partnership shall give notice (including, but not limited to, notification by electronic mail) of such proposed Underwritten Offering to each Holder (together with its Affiliates) holding at least $50.0 million of the then-outstanding Registrable Securities and such notice shall offer such Holders the opportunity to include in such Underwritten Offering such number of Registrable Securities (the “ Included Registrable Securities ”) as each such Holder may request in writing; provided, however , that if the Partnership has been advised by the Managing Underwriter that the inclusion of such Registrable Securities for sale for the benefit of the Holders will have an adverse effect on the price, timing or distribution of the LP Units in the Underwritten Offering, then (A) the Partnership shall not be required to offer such opportunity to the Holders or (B) if any Registrable Securities can be included in the Underwritten Offering in the opinion of the Managing Underwriter, then the amount of such Registrable Securities to be offered for the accounts of Holders shall be determined based on the provisions of Section  2.02(b) . Any notice required to be provided in this Section  2.02(a) to Holders shall be provided on a Business Day pursuant to Section  3.01 hereof and receipt of such notice shall be confirmed by the Holder. Each such Holder shall then have two (2) Business Days (or one (1) Business Day in connection with any overnight or bought Underwritten Offering) after notice has been delivered to request in writing the inclusion of those Registrable Securities in the Underwritten Offering. If no written request for inclusion from a Holder is received within the specified time, each such Holder shall have no further right to participate in such Underwritten Offering. If, at any time after giving

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written notice of its intention to undertake an Underwritten Offering and prior to the closing of such Underwritten Offering, the Partnership shall determine for any reason not to undertake or to delay such Underwritten Offering, the Partnership may, at its election, give written notice of such determination to the Selling Holders and, (x) in the case of a determination not to undertake such Underwritten Offering, shall be relieved of its obligation to sell any Included Registrable Securities in connection with such terminated Underwritten Offering, and (y) in the case of a determination to delay such Underwritten Offering, shall be permitted to delay offering any Included Registrable Securities for the same period as the delay in the Underwritten Offering. Any Selling Holder shall have the right to withdraw such Selling Holder’s request for inclusion of such Selling Holder’s Registrable Securities in such Underwritten Offering by giving written notice to the Partnership of such withdrawal at or prior to the time of pricing of such Underwritten Offering. Any Holder may deliver written notice (an “ Opt-Out Notice ”) to the Partnership requesting that such Holder not receive notice from the Partnership of any proposed Underwritten Offering; provided, however, that such Holder may later revoke any such Opt-Out Notice in writing. Following receipt of an Opt-Out Notice from a Holder (unless subsequently revoked), the Partnership shall not be required to deliver any notice to such Holder pursuant to this Section  2.02(a) and such Holder shall no longer be entitled to participate in Underwritten Offerings by the Partnership pursuant to this Section  2.02(a) . The Holders indicated on Schedule A hereto shall each be deemed to have delivered an Opt-Out Notice as of the date hereof.

(b) Priority . If the Managing Underwriter or Underwriters of any proposed Underwritten Offering advises the Partnership that the total amount of Registrable Securities that the Selling Holders and any other Persons intend to include in such offering exceeds the number that can be sold in such offering without being likely to have an adverse effect on the price, timing or distribution of the LP Units offered or the market for the LP Units, then the LP Units to be included in such Underwritten Offering shall include the number of those Registrable Securities that such Managing Underwriter or Underwriters advises the Partnership can be sold without having such adverse effect, with such number to be allocated (i) first, to the Partnership and (ii) second, pro rata among the Selling Holders who have requested participation in such Underwritten Offering and, except as provided in clause (i), any other holder of securities of the Partnership having rights of registration that are neither expressly senior nor subordinated to the Registrable Securities (the “ Parity Securities ”). The pro rata allocations for each Selling Holder who has requested participation in such Underwritten Offering shall be the product of (a) the aggregate number of those Registrable Securities proposed to be sold in such Underwritten Offering multiplied by (b) the fraction derived by dividing (x) the number of those Registrable Securities owned on the Closing Date by such Selling Holder by (y) the aggregate number of those Registrable Securities owned on the Closing Date by all Selling Holders plus the aggregate number of Parity Securities owned on the Closing Date by all holders of Parity Securities that are participating in the Underwritten Offering.

(c) Termination of Piggyback Registration Rights . Each Holder’s rights under Section  2.02 shall terminate upon such Holder (together with its Affiliates) ceasing to hold at least $50.0 million of those Registrable Securities. Each Holder shall notify the Partnership in writing when such Holder holds less than $50.0 million of those Registrable Securities.

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Section 2.03 Delay Rights . Notwithstanding anything to the contrary contained herein, the Partnership may, upon written notice to any Selling Holder whose Registrable Securities are included in the Registration Statements or other registration statement contemplated by this Agreement, suspend such Selling Holder’s use of any prospectus which is a part of the Registration Statements or other registration statement (in which event the Selling Holder shall discontinue sales of the Registrable Securities pursuant to the Registration Statements or other registration statement contemplated by this Agreement but may settle any previously made sales of Registrable Securities) if (i) the Partnership is pursuing an acquisition, merger, reorganization, disposition or other similar transaction and the Partnership determines in good faith that the Partnership’s ability to pursue or consummate such a transaction would be materially adversely affected by any required disclosure of such transaction in the Registration Statements or other registration statement or (ii) the Partnership has experienced some other material non-public event the disclosure of which at such time, in the good faith judgment of the Partnership, would materially adversely affect the Partnership; provided, however , in no event shall the Selling Holders be suspended from selling Registrable Securities pursuant to the Registration Statements or other registration statement for a period that exceeds an aggregate of sixty (60) days in any one hundred eighty (180)-day period or one hundred five (105) days in any three hundred sixty-five (365)-day period, in each case, exclusive of days covered by any lock-up agreement executed by a Selling Holder in connection with any Underwritten Offering. Upon disclosure of such information or the termination of the condition described above, the Partnership shall provide prompt notice to the Selling Holders whose Registrable Securities are included in the Registration Statements, and shall promptly terminate any suspension of sales it has put into effect and shall take such other reasonable actions to permit registered sales of Registrable Securities as contemplated in this Agreement.

If (i) the Selling Holders shall be prohibited from selling their Registrable Securities under the Registration Statements or other registration statement contemplated by this Agreement as a result of a suspension pursuant to the immediately preceding paragraph in excess of the periods permitted therein or (ii) the Registration Statements or other registration statement contemplated by this Agreement is filed and declared effective but, during the Effectiveness Period, shall thereafter cease to be effective or fail to be usable for its intended purpose without being succeeded within 60 Business Days by a post-effective amendment thereto, a supplement to the prospectus or a report filed with the Commission pursuant to Section 13(a), 13(c), 14 or l5(d) of the Exchange Act, then, until the suspension is lifted or a post-effective amendment, supplement or report is filed with the Commission, but not including any day on which a suspension is lifted or such amendment, supplement or report is filed and declared effective, if applicable, the Partnership shall pay the Selling Holders an amount equal to the Liquidated Damages, following the earlier of (x) the date on which the suspension period exceeded the permitted period and (y) the sixty-first (61st) Business Day after the Registration Statement or other registration statement contemplated by this Agreement ceased to be effective or failed to be useable for its intended purposes, as liquidated damages and not as a penalty (for purposes of calculating Liquidated Damages, the date in (x) or (y) above shall be deemed the “90th day,” as used in the definition of Liquidated Damages). For purposes of this paragraph, a suspension shall be deemed lifted on the date that notice that the suspension has been terminated is delivered to the Selling Holders. Liquidated Damages pursuant to this paragraph shall cease to accrue upon the Purchased Units of such Holder becoming eligible for resale without restriction under any section of Rule 144 (or any similar provision then in effect) under the Securities Act, assuming that such Holder is not an Affiliate of the Partnership, and any payment of Liquidated Damages shall be prorated for any period of less than 30 days in which the payment of Liquidated Damages ceases.

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Section 2.04 Underwritten Offerings

(a) Selling Holder Demand Rights . (i) Selling Holders of a majority of the outstanding Registrable Securities or (ii) each Selling Holder that, together with its Affiliates, holds at least $100 million of outstanding Registrable Securities, may request that the Partnership conduct a firm commitment offering of Registrable Securities under a Registration Statement that shall reasonably be expected to generate gross proceeds of at least $100 million. The Partnership shall, at the written request of such Selling Holder(s), enter into an underwriting agreement in a form as is customary in Underwritten Offerings of securities by the Partnership with the Managing Underwriter or Underwriters selected by the Partnership, which shall include, among other provisions, indemnities to the effect and to the extent provided in Section  2.09 , and shall take all such other reasonable actions as are requested by the Managing Underwriter or Underwriters in order to facilitate the disposition of such Registrable Securities; provided, however , that the Partnership shall have no obligation to facilitate or participate in, including entering into any underwriting agreement, more than three (3) Underwritten Offerings requested by the Selling Holders (which shall never occur within 365 days of each other); provided, further , that if the Partnership or any of its respective Affiliates is conducting or actively pursuing a securities offering of the Partnership’s LP Units (other than in connection with any at-the-market offering or similar continuous offering program), then the Partnership may suspend such Selling Holder’s right to request the Partnership to conduct an Underwritten Offering on such Selling Holder’s behalf pursuant to this Section  2.04 .

(b) General Procedures . In connection with any Underwritten Offering under this Agreement, the Partnership shall be entitled to select the Managing Underwriter or Underwriters. In connection with an Underwritten Offering contemplated by this Agreement in which a Selling Holder participates, each Selling Holder and the Partnership shall be obligated to enter into an underwriting agreement that contains such representations, covenants, indemnities and other rights and obligations as are customary in underwriting agreements for firm commitment offerings of securities. No Selling Holder may participate in such Underwritten Offering unless such Selling Holder agrees to sell its Registrable Securities on the basis provided in such underwriting agreement and completes and executes all questionnaires, powers of attorney, indemnities and other documents reasonably required under the terms of such underwriting agreement. Each Selling Holder may, at its option, require that any or all of the representations and warranties by, and the other agreements on the part of, the Partnership to and for the benefit of such underwriters also be made to and for such Selling Holder’s benefit and that any or all of the conditions precedent to the obligations of such underwriters under such underwriting agreement also be conditions precedent to its obligations. No Selling Holder shall be required to make any representations or warranties to or agreements with the Partnership or the underwriters other than representations, warranties or agreements regarding such Selling Holder, its authority to enter into such underwriting agreement and to sell, and its ownership of, the securities being registered on its behalf, its intended method of distribution and any other representation required by Law. If any Selling Holder disapproves of the terms of an underwriting, such Selling Holder may elect to withdraw therefrom by notice to the Partnership and the Managing Underwriter; provided, however , that such withdrawal must be made up to and including the time of pricing of

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such Underwritten Offering. No such withdrawal or abandonment shall affect the Partnership’s obligation to pay Registration Expenses. The Partnership’s management may but shall not be required to participate in a roadshow or similar marketing effort in connection with any Underwritten Offering.

Section 2.05 Sale Procedures . In connection with its obligations under this Article II, the Partnership will, as expeditiously as possible:

(a) prepare and file with the Commission such amendments and supplements to the Registration Statements and the prospectus used in connection therewith as may be necessary to keep the Registration Statements effective for the Effectiveness Period and as may be necessary to comply with the provisions of the Securities Act with respect to the disposition of all Registrable Securities covered by the Registration Statements;

(b) if a prospectus supplement will be used in connection with the marketing of an Underwritten Offering from the Registration Statements and the Managing Underwriter at any time shall notify the Partnership in writing that, in the sole judgment of such Managing Underwriter, inclusion of detailed information to be used in such prospectus supplement is of material importance to the success of the Underwritten Offering of such Registrable Securities, the Partnership shall use its commercially reasonable efforts to include such information in such prospectus supplement;

(c) furnish to each Selling Holder (i) as far in advance as reasonably practicable before filing the Registration Statements or any other registration statement contemplated by this Agreement or any supplement or amendment thereto, upon request, copies of reasonably complete drafts of all such documents proposed to be filed (including exhibits and each document incorporated by reference therein to the extent then required by the rules and regulations of the Commission), and provide each such Selling Holder the opportunity to object to any information pertaining to such Selling Holder and its plan of distribution that is contained therein and make the corrections reasonably requested by such Selling Holder with respect to such information prior to filing the Registration Statements or such other registration statement or supplement or amendment thereto, and (ii) such number of copies of the Registration Statements or such other registration statement and the prospectus included therein and any supplements and amendments thereto as such Selling Holder may reasonably request in order to facilitate the public sale or other disposition of the Registrable Securities covered by such Registration Statements or other registration statement;

(d) if applicable, use its commercially reasonable efforts to register or qualify the Registrable Securities covered by the Registration Statements or any other registration statement contemplated by this Agreement under the securities or blue sky laws of such jurisdictions as the Selling Holders or, in the case of an Underwritten Offering, the Managing Underwriter, shall reasonably request; provided, however , that the Partnership will not be required to qualify generally to transact business in any jurisdiction where it is not then required to so qualify or to take any action that would subject it to general service of process in any such jurisdiction where it is not then so subject;

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(e) promptly notify each Selling Holder, at any time when a prospectus relating thereto is required to be delivered by any of them under the Securities Act, of (i) the filing of the Registration Statements or any other registration statement contemplated by this Agreement or any prospectus or prospectus supplement to be used in connection therewith, or any amendment or supplement thereto, and, with respect to such Registration Statements or any other registration statement or any post-effective amendment thereto, when the same has become effective; and (ii) the receipt of any written comments from the Commission with respect to any filing referred to in clause (i)  and any written request by the Commission for amendments or supplements to the Registration Statements or any other registration statement or any prospectus or prospectus supplement thereto;

(f) immediately notify each Selling Holder, at any time when a prospectus relating thereto is required to be delivered under the Securities Act, of (i) the happening of any event as a result of which the prospectus or prospectus supplement contained in the Registration Statements or any other registration statement contemplated by this Agreement, as then in effect, includes an untrue statement of a material fact or omits to state any material fact required to be stated therein or necessary to make the statements therein not misleading (in the case of any prospectus contained therein, in the light of the circumstances under which a statement is made); (ii) the issuance or express threat of issuance by the Commission of any stop order suspending the effectiveness of the Registration Statements or any other registration statement contemplated by this Agreement, or the initiation of any proceedings for that purpose; or (iii) the receipt by the Partnership of any notification with respect to the suspension of the qualification of any Registrable Securities for sale under the applicable securities or blue sky laws of any jurisdiction. Following the provision of such notice, the Partnership agrees, subject to Section  2.03 of this Agreement, to as promptly as practicable amend or supplement the prospectus or prospectus supplement or take other appropriate action so that the prospectus or prospectus supplement does not include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading in the light of the circumstances then existing and to take such other commercially reasonable action as is necessary to remove a stop order, suspension, threat thereof or proceedings related thereto;

(g) upon request and subject to appropriate confidentiality obligations, furnish to each Selling Holder copies of any and all transmittal letters or other correspondence with the Commission or any other governmental agency or self-regulatory body or other body having jurisdiction (including any domestic or foreign securities exchange) relating to such offering of Registrable Securities;

(h) in the case of an Underwritten Offering, furnish upon request, (i) an opinion of counsel for the Partnership dated the date of the closing under the underwriting agreement and (ii) a “cold comfort” letter, dated the pricing date of such Underwritten Offering and a letter of like kind dated the date of the closing under the underwriting agreement, in each case, signed by the independent public accountants who have certified the Partnership’s financial statements included or incorporated by reference into the applicable registration statement, and each of the opinion and the “cold comfort” letter shall be in customary form and covering substantially the same matters with respect to such registration statement (and the prospectus and any prospectus supplement included therein) as have been customarily covered in opinions of issuer’s counsel and in accountants’ letters delivered to the underwriters in Underwritten Offerings of securities by the Partnership and such other matters as such underwriters and Selling Holders may reasonably request;

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(i) otherwise use its commercially reasonable efforts to comply with all applicable rules and regulations of the Commission, and make available to its security holders, as soon as reasonably practicable, an earnings statement, which earnings statement shall satisfy the provisions of Section 11(a) of the Securities Act and Rule 158 promulgated thereunder;

(j) make available to the appropriate representatives of the Managing Underwriter and Selling Holders access to such information and Partnership personnel as is reasonable and customary to enable such parties to establish a due diligence defense under the Securities Act; provided , that the Partnership need not disclose any non-public information to any such representative unless and until such representative has entered into a confidentiality agreement with the Partnership;

(k) cause all such Registrable Securities registered pursuant to this Agreement to be listed on each securities exchange or nationally recognized quotation system on which similar securities issued by the Partnership are then listed;

(l) use its commercially reasonable efforts to cause the Registrable Securities to be registered with or approved by such other governmental agencies or authorities as may be necessary by virtue of the business and operations of the Partnership to enable the Selling Holders to consummate the disposition of such Registrable Securities;

(m) provide a transfer agent and registrar for all Registrable Securities covered by such registration statement not later than the effective date of such registration statement;

(n) enter into customary agreements and take such other actions as are reasonably requested by the Selling Holders or the underwriters, if any, in order to expedite or facilitate the disposition of such Registrable Securities; and

(o) if requested by a Selling Holder, (i) incorporate in a prospectus supplement or post-effective amendment to the Registration Statements or any other registration statement contemplated by this Agreement such information as such Selling Holder reasonably requests to be included therein relating to the sale and distribution of Registrable Securities, including information with respect to the number of Registrable Securities being offered or sold, the purchase price being paid therefor and any other terms of the offering of the Registrable Securities to be sold in such offering and (ii) make all required filings of such prospectus supplement or post-effective amendment after being notified of the matters to be incorporated in such prospectus supplement or post-effective amendment.

The Partnership shall not name a Holder as an underwriter as defined in Section 2(a)(11) of the Securities Act in any registration statement without such Holder’s consent. If the staff of the Commission requires the Partnership to name any Holder as an underwriter as defined in Section 2(a)(11) of the Securities Act, and such Holder does not consent thereto, then such Holder’s Registrable Securities shall not be included on the Registration Statement (or any other registration statement contemplated by this Agreement), such Holder shall no longer be entitled to receive Liquidated Damages under this Agreement with respect thereto, the Partnership shall have no further obligations hereunder with respect to Registrable Securities held by such Holder and such Holder shall be deemed to have terminated this Agreement with respect to such Holder.

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Each Selling Holder, upon receipt of notice from the Partnership of the happening of any event of the kind described in subsection (f)  of this Section  2.05 , shall forthwith discontinue offers and sales of the Registrable Securities by means of a prospectus or prospectus supplement until such Selling Holder’s receipt of the copies of the supplemented or amended prospectus contemplated by subsection (f ) of this Section  2.05 or until it is advised in writing by the Partnership that the use of the prospectus may be resumed and has received copies of any additional or supplemental filings incorporated by reference in the prospectus, and, if so directed by the Partnership, such Selling Holder will, or will request the Managing Underwriter or Underwriters, if any, to deliver to the Partnership (at the Partnership’s expense) all copies in their possession or control, other than permanent file copies then in such Selling Holder’s possession, of the prospectus covering such Registrable Securities current at the time of receipt of such notice.

Section 2.06 Cooperation by Holders . The Partnership shall have no obligation to include Registrable Securities of a Holder in the Registration Statements or in an Underwritten Offering pursuant to Section 2.02(a) who has failed to timely furnish such information that the Partnership determines, after consultation with its counsel, is reasonably required in order for the registration statement or prospectus supplement, as applicable, to comply with the Securities Act.

Section 2.07 Restrictions on Public Sale by Holders of Registrable Securities . Each Holder of Registrable Securities agrees, if requested by the underwriters of an Underwritten Offering, to enter into a customary letter agreement with underwriters providing such Holder will not effect any public sale or distribution of the class of Registrable Securities subject to the Underwritten Offering during the sixty (60) calendar day period beginning on the date of a prospectus or prospectus supplement filed with the Commission with respect to the pricing of any Underwritten Offering, provided that (i) the duration of the foregoing restrictions shall be no longer than the duration of the shortest restriction generally imposed by the underwriters on the Partnership or the officers, directors or any other Affiliate of the Partnership on whom a restriction is imposed and (ii) the restrictions set forth in this Section 2.07 shall not apply to any Registrable Securities that are included in such Underwritten Offering by such Holder. In addition, this Section 2.07 shall not apply to any Holder that is not entitled to participate in such Underwritten Offering, whether because such Holder delivered an Opt-Out Notice prior to receiving notice of the Underwritten Offering, because such Holder holds less than $50.0 million of the then-outstanding Registrable Securities or because the Registrable Securities held by such Holder may be disposed of without restriction pursuant to any section of Rule 144 (or any similar provision then in effect) under the Securities Act.

Section 2.08 Expenses

(a) Expenses . The Partnership will pay all reasonable Registration Expenses as determined in good faith, including, in the case of an Underwritten Offering, whether or not any sale is made pursuant to such Underwritten Offering. Each Selling Holder shall pay its pro rata share of all Selling Expenses in connection with any sale of its Registrable Securities hereunder. In addition, except as otherwise provided in Section  2.09 hereof, the Partnership shall not be responsible for legal and professional fees incurred by Holders in connection with the exercise of such Holders’ rights hereunder.

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(b) Certain Definitions . “ Registration Expenses ” means all expenses incident to the Partnership’s performance under or compliance with this Agreement to effect the registration of Registrable Securities on the Registration Statements pursuant to Section  2.01(a) or an Underwritten Offering covered under this Agreement, and the disposition of such Registrable Securities, including, without limitation, all registration, filing, securities exchange listing and NYSE fees, all registration, filing, qualification and other fees and expenses of complying with securities or blue sky laws, fees of the Financial Industry Regulatory Authority, fees of transfer agents and registrars, all word processing, duplicating and printing expenses, any transfer taxes and the fees and disbursements of counsel and independent public accountants for the Partnership, including the expenses of any special audits or “cold comfort” letters required by or incident to such performance and compliance. “ Selling Expenses ” means all underwriting fees, discounts and selling commissions or similar fees or arrangements allocable to the sale of the Registrable Securities.

Section 2.09 Indemnification

(a) By the Partnership . In the event of a registration of any Registrable Securities under the Securities Act pursuant to this Agreement, the Partnership will indemnify and hold harmless each Selling Holder thereunder, its directors, officers, employees and agents and each Person, if any, who controls such Selling Holder within the meaning of the Securities Act and the Exchange Act, and its directors, officers, employees or agents (collectively, the “ Selling Holder Indemnified Persons ”), against any losses, claims, damages, expenses or liabilities (including reasonable attorneys’ fees and expenses) (collectively, “ Losses ”), joint or several, to which such Selling Holder Indemnified Person may become subject under the Securities Act, the Exchange Act or otherwise, insofar as such Losses (or actions or proceedings, whether commenced or threatened, in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact (in the case of any prospectus, in light of the circumstances under which such statement is made) contained in the Registration Statements or any other registration statement contemplated by this Agreement, any preliminary prospectus, prospectus supplement, free writing prospectus or final prospectus contained therein, or any amendment or supplement thereof, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein (in the case of a prospectus, in light of the circumstances under which they were made) not misleading, and will reimburse each such Selling Holder Indemnified Person for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such Loss or actions or proceedings; provided, however , that the Partnership will not be liable in any such case if and to the extent that any such Loss arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission so made in conformity with information furnished by such Selling Holder Indemnified Person in writing specifically for use in the Registration Statements or such other registration statement, prospectus supplement, or free writing prospectus, as applicable. Such indemnity shall remain in full force and effect regardless of any investigation made by or on behalf of such Selling Holder Indemnified Person, and shall survive the transfer of such securities by such Selling Holder.

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(b) By Each Selling Holder . Each Selling Holder agrees severally and not jointly to indemnify and hold harmless the Partnership, the General Partner, its directors, officers, employees and agents and each Person, if any, who controls the Partnership within the meaning of the Securities Act or of the Exchange Act, and its directors, officers, employees and agents, to the same extent as the foregoing indemnity from the Partnership to the Selling Holders, but only with respect to information regarding such Selling Holder furnished in writing by or on behalf of such Selling Holder expressly for inclusion in the Registration Statements or any other registration statement contemplated by this Agreement, any preliminary prospectus, prospectus supplement, free writing prospectus or final prospectus contained therein, or any amendment or supplement thereof; provided, however , that the liability of each Selling Holder shall not be greater in amount than the dollar amount of the proceeds (net of any Selling Expenses) received by such Selling Holder from the sale of the Registrable Securities giving rise to such indemnification.

(c) Notice . Promptly after receipt by an indemnified party hereunder of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party hereunder, notify the indemnifying party in writing thereof, but the omission so to notify the indemnifying party shall not relieve it from any liability that it may have to any indemnified party other than under this Section  2.09 . In any action brought against any indemnified party, it shall notify the indemnifying party of the commencement thereof. The indemnifying party shall be entitled to participate in and, to the extent it shall wish, to assume and undertake the defense thereof with counsel reasonably satisfactory to such indemnified party and, after notice from the indemnifying party to such indemnified party of its election so to assume and undertake the defense thereof, the indemnifying party shall not be liable to such indemnified party under this Section  2.09 for any legal expenses subsequently incurred by such indemnified party in connection with the defense thereof other than reasonable costs of investigation and of liaison with counsel so selected; provided, however , that, (i) if the indemnifying party has failed to assume the defense or employ counsel reasonably acceptable to the indemnified party or (ii) if the defendants in any such action include both the indemnified party and the indemnifying party and counsel to the indemnified party shall have concluded that there may be reasonable defenses available to the indemnified party that are different from or additional to those available to the indemnifying party, or if the interests of the indemnified party reasonably may be deemed to conflict with the interests of the indemnifying party, then the indemnified party shall have the right to select a separate counsel and to assume such legal defense and otherwise to participate in the defense of such action, with the reasonable expenses and fees of such separate counsel and other reasonable expenses related to such participation to be reimbursed by the indemnifying party as incurred. Notwithstanding any other provision of this Agreement, no indemnifying party shall settle any action brought against any indemnified party with respect to which such indemnified party is entitled to indemnification hereunder without the consent of the indemnified party, unless the settlement thereof imposes no liability or obligation on, and includes a complete and unconditional release from all liability of, the indemnified party.

(d) Contribution . If the indemnification provided for in this Section  2.09 is held by a court or government agency of competent jurisdiction to be unavailable to any indemnified party or is insufficient to hold them harmless in respect of any Losses, then each such indemnifying party, in lieu of indemnifying such indemnified party, shall contribute to the amount paid or

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payable by such indemnified party as a result of such Loss in such proportion as is appropriate to reflect the relative fault of the indemnifying party on the one hand and of such indemnified party on the other in connection with the statements or omissions that resulted in such Losses, as well as any other relevant equitable considerations; provided, however , that in no event shall such Selling Holder be required to contribute an aggregate amount in excess of the dollar amount of proceeds (net of Selling Expenses) received by such Selling Holder from the sale of Registrable Securities giving rise to such indemnification. The relative fault of the indemnifying party on the one hand and the indemnified party on the other shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact has been made by, or relates to, information supplied by such party, and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The parties hereto agree that it would not be just and equitable if contributions pursuant to this paragraph were to be determined by pro rata allocation or by any other method of allocation that does not take account of the equitable considerations referred to herein. The amount paid by an indemnified party as a result of the Losses referred to in the first sentence of this paragraph shall be deemed to include any legal and other expenses reasonably incurred by such indemnified party in connection with investigating or defending any Loss that is the subject of this paragraph. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any Person who is not guilty of such fraudulent misrepresentation.

(e) Other Indemnification . The provisions of this Section  2.09 shall be in addition to any other rights to indemnification or contribution that an indemnified party may have pursuant to law, equity, contract or otherwise.

Section 2.10 Rule 144 Reporting . With a view to making available the benefits of certain rules and regulations of the Commission that may permit the sale of the Registrable Securities to the public without registration, the Partnership agrees to use its commercially reasonable efforts to:

(a) make and keep public information regarding the Partnership available, as those terms are understood and defined in Rule 144 under the Securities Act, at all times from and after the date hereof;

(b) file with the Commission in a timely manner all reports and other documents required of the Partnership under the Securities Act and the Exchange Act at all times from and after the date hereof; and

(c) so long as a Holder owns any Registrable Securities, furnish, unless otherwise available via EDGAR, to such Holder forthwith upon request a copy of the most recent annual or quarterly report of the Partnership, and such other reports and documents so filed as such Holder may reasonably request in availing itself of any rule or regulation of the Commission allowing such Holder to sell any such securities without registration.

Solely for purposes of this Section 2.10, the term “Registrable Securities” shall be read without regard to the limitation set forth in Section 1.02(e).

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Section 2.11 Transfer or Assignment of Registration Rights . The rights to cause the Partnership to register Registrable Securities granted to the Investors by the Partnership under this Article II may be transferred or assigned by any Investor to one or more transferees or assignees of Registrable Securities; provided, however , that (a) unless the transferee or assignee is an Affiliate of, and after such transfer or assignment continues to be an Affiliate of, such Investor, the amount of Registrable Securities transferred or assigned to such transferee or assignee shall represent at least $50.0 million of Registrable Securities, (b) the Partnership is given written notice prior to any said transfer or assignment, stating the name and address of each such transferee or assignee and identifying the securities with respect to which such registration rights are being transferred or assigned, (c) each such transferee or assignee assumes in writing responsibility for its portion of the obligations of such Investor under this Agreement and (d) the transferor or assignor is not relieved of any obligations or liabilities hereunder arising out of events occurring prior to such transfer.

Section 2.12 Limitation on Subsequent Registration Rights . From and after the date hereof, the Partnership shall not, without the prior written consent of the Holders of a majority of the Registrable Securities, enter into any agreement with any current or future holder of any securities of the Partnership that would allow such current or future holder to require the Partnership to include securities in any registration statement filed by the Partnership on a basis other than pari passu with, or expressly subordinate to the rights of, the Holders of Registrable Securities hereunder.

ARTICLE III

MISCELLANEOUS

Section 3.01 Communications . All notices and other communications provided for or permitted hereunder shall be made in writing by facsimile, electronic mail, courier service or personal delivery:

(a) if to an Investor:

To the respective address listed on Schedule A hereof

(b) if to a transferee of an Investor, to such Holder at the address provided pursuant to Section  2.11 above; and

(c) if to the Partnership:

Buckeye Partners, L.P.

One Greenway Plaza, Suite 600

Houston, TX 77046

Attention: General Counsel

Facsimile: 610.904.4006

with a copy to:

Vinson & Elkins L.L.P.

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1001 Fannin Street, Suite 2500

Houston, TX 77002

Attention: E. Ramey Layne

Facsimile: 713.751.5396

All such notices and communications shall be deemed to have been received at the time delivered by hand, if personally delivered; when receipt acknowledged, if sent via facsimile or sent via Internet electronic mail; and when actually received, if sent by courier service or any other means.

Section 3.02 Successor and Assigns . This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each of the parties, including subsequent Holders of Registrable Securities to the extent permitted herein.

Section 3.03 Additional Investors . If Investors who purchased Additional Units include Affiliates who were not Investors as of the Closing Date, then each additional Purchaser shall execute the Joinder Agreement attached hereto as Exhibit A.

Section 3.04 Assignment of Rights . All or any portion of the rights and obligations of any Investor under this Agreement may be transferred or assigned by such Investor only in accordance with Section 2.11 hereof.

Section 3.05 Recapitalization, Exchanges, Etc. Affecting the Units . The provisions of this Agreement shall apply to the full extent set forth herein with respect to any and all units of the Partnership or any successor or assign of the Partnership (whether by merger, consolidation, sale of assets or otherwise) that may be issued in respect of, in exchange for or in substitution of, the Registrable Securities, and shall be appropriately adjusted for combinations, unit splits, recapitalizations, pro rata distributions of units and the like occurring after the date of this Agreement.

Section 3.06 Aggregation of Registrable Securities . All Registrable Securities held or acquired by Persons who are Affiliates of one another shall be aggregated together for the purpose of determining the availability of any rights and applicability of any obligations under this Agreement.

Section 3.07 Specific Performance . Damages in the event of breach of this Agreement by a party hereto may be difficult, if not impossible, to ascertain, and it is therefore agreed that each such Person, in addition to and without limiting any other remedy or right it may have, will have the right to an injunction or other equitable relief in any court of competent jurisdiction, enjoining any such breach, and enforcing specifically the terms and provisions hereof, and each of the parties hereto hereby waives any and all defenses it may have on the ground of lack of jurisdiction or competence of the court to grant such an injunction or other equitable relief. The existence of this right will not preclude any such Person from pursuing any other rights and remedies at law or in equity that such Person may have.

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Section 3.08 Counterparts . This Agreement may be executed in any number of counterparts and by different parties hereto in separate counterparts, each of which counterparts, when so executed and delivered, shall be deemed to be an original and all of which counterparts, taken together, shall constitute but one and the same Agreement. In the event that any signature is delivered by facsimile transmission or by e-mail delivery of a “.pdf” format data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile or “.pdf” signature page were an original thereof.

Section 3.09 Headings . The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof.

Section 3.10 Governing Law . THIS AGREEMENT WILL BE CONSTRUED IN ACCORDANCE WITH, AND GOVERNED BY, THE LAWS OF THE STATE OF NEW YORK.

Section 3.11 Severability of Provisions . Any provision of this Agreement which is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof or affecting or impairing the validity or enforceability of such provision in any other jurisdiction.

Section 3.12 Entire Agreement . This Agreement and the Unit Purchase Agreement are intended by the parties as a final expression of their agreement and intended to be a complete and exclusive statement of the agreement and understanding of the parties hereto in respect of the subject matter contained herein. There are no restrictions, promises, representations, warranties or undertakings, other than those set forth or referred to herein with respect to the rights granted by the Partnership set forth herein. This Agreement and the Unit Purchase Agreement supersede all prior agreements and understandings between the parties with respect to such subject matter.

Section 3.13 Amendment . This Agreement may be amended only by means of a written amendment signed by the Partnership and the Holders of a majority of the then outstanding Registrable Securities; provided, however, that no such amendment shall materially and adversely affect the rights of any Holder hereunder without the consent of such Holder.

Section 3.14 No Presumption . If any claim is made by a party relating to any conflict, omission, or ambiguity in this Agreement, no presumption or burden of proof or persuasion shall be implied by virtue of the fact that this Agreement was prepared by or at the request of a particular party or its counsel.

Section 3.15 Obligations Limited to Parties to Agreement . Each of the Parties hereto covenants, agrees and acknowledges that no Person other than the Investors (and their permitted transferees and assignees) and the Partnership shall have any obligation hereunder and that, notwithstanding that one or more of the Investors may be a corporation, partnership or limited liability company, no recourse under this Agreement or under any documents or instruments delivered in connection herewith or therewith shall be had against any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the Investors or any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the

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foregoing, whether by the enforcement of any assessment or by any legal or equitable proceeding, or by virtue of any applicable Law, it being expressly agreed and acknowledged that no personal liability whatsoever shall attach to, be imposed on or otherwise be incurred by any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the Investors or any former, current or future director, officer, employee, agent, general or limited partner, manager, member, stockholder or Affiliate of any of the foregoing, as such, for any obligations of the Investors under this Agreement or any documents or instruments delivered in connection herewith or therewith or for any claim based on, in respect of or by reason of such obligation or its creation, except in each case for any transferee or assignee of a Investor hereunder.

Section 3.16 Independent Nature of Investor ’ s Obligations . The obligations of each Investor (and their permitted transferees and assignees) under this Agreement are several and not joint with the obligations of any other Investor , and no Investor shall be responsible in any way for the performance of the obligations of any other Investor under this Agreement. Nothing contained herein, and no action taken by any Investor pursuant thereto, shall be deemed to constitute the Investors as a partnership, an association, a joint venture or any other kind of group or entity, or create a presumption that the Investors are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by this Agreement. Each Investor shall be entitled to independently protect and enforce its rights, including without limitation, the rights arising out of this Agreement, and it shall not be necessary for any other Investor to be joined as an additional party in any proceeding for such purpose.

Section 3.17 Interpretation . Article and Section references to this Agreement, unless otherwise specified. All references to instruments, documents, contracts and agreements are references to such instruments, documents, contracts and agreements as the same may be amended, supplemented and otherwise modified from time to time, unless otherwise specified. The word “including” shall mean “including but not limited to.” Whenever any determination, consent or approval is to be made or given by an Investor under this Agreement, such action shall be in such Investor’s sole discretion unless otherwise specified.

[Signature pages to follow]

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IN WITNESS WHEREOF, the Parties hereto execute this Agreement, effective as of the date first above written.

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Signature Page to Registration Rights Agreement

Schedule A to Registration Rights Agreement

Exhibit A – Form of Joinder Agreement

This Joinder Agreement is executed by the undersigned pursuant to the Registration Rights Agreement, dated as of [●], 2018 (the “ Agreement ”) among Buckeye Partners, L.P. (the “ Partnership ”) and the investors party thereto (the “ Investors ”), which is incorporated herein by reference. Capitalized terms used but not defined herein shall have the meaning given to such terms in the Agreement. By the execution of this Joinder Agreement, the undersigned agrees as follows:

1. The undersigned acknowledges that the Partnership has agreed to provide the registration and other rights set forth in the Agreement for the benefit of the Investors pursuant to the Unit Purchase Agreement.

2. The undersigned hereby joins in, and agrees to be bound by and subject to, the Agreement, with the same force and effect as if the undersigned were originally an Investor party thereto.

3. Any notice required or permitted by the Agreement shall be given to the undersigned at the address listed below.

4. The Partnership and the General Partner each hereby acknowledge and agree that the undersigned shall be deemed an Investor under the Registration Rights Agreement and that such Investor shall be entitled to all of the rights and benefits, and subject to all of the obligations, of an Investor under the Agreement from and after April 10, 2018 as if the undersigned was a party thereto as of the Closing Date.

EXECUTED AND DATED as of this [ ● ] day of [ ● ], 2018.

Exhibit A to Registration Rights Agreement