Exhibit 5.1

May 15, 2014

Genesis Energy, L.P.

Genesis Energy Finance Corporation

919 Milam, Suite 2100

Houston, Texas 77002

Ladies and Gentlemen:

We have acted as counsel to Genesis Energy, L.P., a Delaware limited partnership (the “Company”), and Genesis Energy Finance Corporation, a Delaware corporation (“Finance Corp” and, together with the Company, the “Issuers”), in connection with the registration, pursuant to a Registration Statement on Form S-3 (File No. 333-180876), as amended by Post-Effective Amendment No. 1 (as so amended, the “Registration Statement”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Act”), of the offering and sale by the Issuers of $350,000,000 aggregate principal amount of 5.625% Senior Notes due 2024 (the “Notes”), including the guarantees (the “Guarantees”) of the Notes by the Company’s subsidiaries (the “Subsidiary Guarantors” and, together with the Issuers, the “Obligors”) listed on Schedule I hereto (including the Specified Guarantors (as defined below)), to be issued under an Indenture (the “Base Indenture”) dated as of May 15, 2014, among the Company, Finance Corp, the Subsidiary Guarantors and U.S. Bank, National Association, as Trustee (the “Trustee”), as supplemented by the Supplemental Indenture thereto dated as of May 15, 2014, among the Company, Finance Corp, the Subsidiary Guarantors and the Trustee (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), and sold pursuant to the terms of an underwriting agreement (the “Underwriting Agreement”), dated May 12, 2014, among the Obligors, RBC Capital Markets, LLC, as representative of the underwriters named therein (the “Underwriters”), and Raymond James & Associates, Inc., as “qualified independent underwriter” within the meaning of Rule 5121(f)(12) of the Financial Industry Regulatory Authority, Inc. For purposes of this opinion letter, the term “Specified Guarantors” means the Subsidiary Guarantors other than (i) Genesis Pipeline Alabama, LLC, (ii) Red River Terminals, L.L.C. and (iii) TDC, L.L.C. This opinion is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Act.

We have examined originals or certified copies of such corporate or other entity records of the Issuers and the Specified Guarantors and other certificates and documents of officials of the Issuers and the Specified Guarantors, public officials and others as we have deemed appropriate for purposes of this letter. We have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of all documents submitted to us as originals, the conformity to authentic original documents of all copies submitted to us as conformed, certified or reproduced copies and that the Notes will conform to the specimen thereof we have reviewed. We have also assumed the existence and entity power to execute and

deliver the Indenture of, and the due authorization, execution and delivery of the Indenture by, each of the parties thereto other than the Issuers and the Specified Guarantors, and that the Indenture is a valid and binding obligation of the Trustee, enforceable against the Trustee in accordance with its terms. As to various questions of fact relevant to this letter, we have relied, without independent investigation, upon certificates of public officials and certificates of officers of the Issuers and the Specified Guarantors, all of which we assume to be true, correct and complete.

Based upon the foregoing and subject to the assumptions, exceptions, qualifications and limitations set forth herein, we are of the opinion that when the Notes have been duly executed by the Issuers, duly authenticated by the Trustee in accordance with the terms of the Indenture, and issued and delivered by or on behalf of the Issuers to and paid for by the Underwriters pursuant to the terms of the Underwriting Agreement, (i) the Notes will be valid and binding obligations of the Issuers, enforceable against the Issuers in accordance with their terms, and (ii) the Guarantees of the Subsidiary Guarantors will be valid and binding obligations of the Subsidiary Guarantors, enforceable against the Subsidiary Guarantors in accordance with their terms.

The opinions and other matters in this letter are qualified in their entirety and subject to the following:

We hereby consent to the filing of this opinion as an exhibit to a Current Report on Form 8-K filed by the Company with the Commission on or about the date hereof, to the incorporation by reference of this opinion into the Registration Statement and to the use of our name in the Preliminary Prospectus Supplement dated May 12, 2014 and the Final Prospectus Supplement dated May 12, 2014 forming a part of the Registration Statement under the caption “Legal Matters.” In giving this consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Act and the rules and regulations thereunder.

Very truly yours,

/s/ AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.

AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.

Schedule I

Guarantors