GENESIS ENERGY, L.P. GENESIS ENERGY FINANCE CORPORATION and the Guarantors named herein 7 7/8% SENIOR NOTES DUE 2018 FIFTH SUPPLEMENTAL INDENTURE (SUBSIDIARY GUARANTEE) DATED AS OF SEPTEMBER 13, 2011 U.S. BANK NATIONAL ASSOCIATION, Trustee

EXHIBIT 4.6

GENESIS ENERGY, L.P.

GENESIS ENERGY FINANCE CORPORATION

and

the Guarantors named herein

7  ⁷/8% SENIOR NOTES DUE 2018

FIFTH SUPPLEMENTAL INDENTURE

(SUBSIDIARY GUARANTEE)

DATED AS OF SEPTEMBER 13, 2011

U.S. BANK NATIONAL ASSOCIATION,

Trustee

This FIFTH SUPPLEMENTAL INDENTURE, dated as of September 13, 2011, is among Genesis Energy, L.P., a Delaware limited partnership (the “Company”), Genesis Energy Finance Corporation, a Delaware corporation (“Finance Corp.” and, together with the Company, the “Issuers”), the Guarantors specified on the signature page hereto (the “Guarantors”), Milam Services, Inc., a Delaware corporation (“Milam Services”), and GEL Tex Marketing, LLC, a Delaware limited liability company (together with Milam Services, the “New Guarantors”), and U.S. Bank National Association, a national banking association, as Trustee.

RECITALS

WHEREAS, the Issuers, the Guarantors and the Trustee are parties to an Indenture, dated as of November 18, 2010, as supplemented by the Supplemental Indenture, dated as of November 24, 2010, the Second Supplemental Indenture, dated as of December 27, 2010, the Third Supplemental Indenture, dated as of January 28, 2011 and the Fourth Supplemental Indenture, dated as of June 30, 2011 (as so supplemented, the “Indenture”), pursuant to which the Issuers have issued $250,000,000 in the aggregate principal amount of 7 ⁷/8% Senior Notes due 2018 (the “Notes”);

WHEREAS, Section 9.01(7) of the Indenture provides that the Issuers, the Guarantors and the Trustee may amend or supplement the Indenture in order to comply with Section 4.13 or 10.03 thereof, without the consent of the Holders of the Notes; and

WHEREAS, all acts and things necessary to make this Supplemental Indenture a valid and legally binding agreement according to its terms, and a valid and legally binding amendment of and supplement to, the Indenture, have been duly done and performed.

NOW, THEREFORE, to comply with the provisions of the Indenture and in consideration of the above premises, the Issuers, the Guarantors, the New Guarantors and the Trustee covenant and agree for the equal and proportionate benefit of the respective Holders of the Notes as follows:

ARTICLE 1

Section 1.01. This Fifth Supplemental Indenture is supplemental to the Indenture and does and shall be deemed to form a part of, and shall be construed in connection with and as part of, the Indenture for any and all purposes.

Section 1.02. This Fifth Supplemental Indenture shall become effective immediately upon its execution and delivery by each of the Issuers, the Guarantors, the New Guarantors and the Trustee.

ARTICLE 2

From this date, in accordance with Section 4.13 or 10.03 and by executing this Fifth Supplemental Indenture, each New Guarantor shall be subject to the provisions of the Indenture to the extent provided for in Article 10 thereunder. Each New Guarantor hereby becomes a party to the Indenture as a Guarantor and as such will have all of the rights and be subject to all of the obligations and agreements of a Guarantor under the Indenture. Each New Guarantor agrees to be bound by all of the provisions of the Indenture applicable to a Guarantor and to perform all of the obligations and agreements of a Guarantor under the Indenture.

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ARTICLE 3

Section 3.01. Except as specifically modified herein, the Indenture and the Notes are in all respects ratified and confirmed (mutatis mutandis) and shall remain in full force and effect in accordance with their terms with all capitalized terms used herein without definition having the same respective meanings ascribed to them as in the Indenture.

Section 3.02. Except as otherwise expressly provided herein, no duties, responsibilities or liabilities are assumed, or shall be construed to be assumed, by the Trustee by reason of this Fifth Supplemental Indenture. This Fifth Supplemental Indenture is executed and accepted by the Trustee subject to all the terms and conditions set forth in the Indenture with the same force and effect as if those terms and conditions were repeated at length herein and made applicable to the Trustee with respect hereto.

Section 3.03. THIS FIFTH SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

Section 3.04. The parties may sign any number of copies of this Fifth Supplemental Indenture. Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement.

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IN WITNESS WHEREOF, the parties hereto have caused this Fifth Supplemental Indenture to be duly executed, all as of the date first written above.

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