SUPPLEMENTAL INDENTURE

Exhibit 4.35D

SUPPLEMENTAL INDENTURE

SUPPLEMENTAL INDENTURE dated as of July 30, 2012 (this “Supplemental Indenture”) among CLEAN HARBORS, INC., a Massachusetts corporation (the “Issuer” or the “Company”), the Guarantors (as defined in the Indenture referred to below) and U.S. BANK NATIONAL ASSOCIATION, as Trustee (the “Trustee”) and as Notes Collateral Agent (the “Notes Collateral Agent”) under the Indenture referred to below.

W I T N E S S E T H:

WHEREAS, the Company, the Guarantors, the Trustee and the Notes Collateral Agent have heretofore executed and delivered an Indenture, dated as of August 14, 2009 (the “Base Indenture”), as supplemented by Supplemental Indentures dated as of December 31, 2009, June 22, 2011 and August 17, 2011 (the “Existing Supplemental Indentures” and, together with the Base Indenture, the “Indenture”), providing for the issuance of 7 5/8% Senior Secured Notes due 2016 of the Company (the “Securities”);

WHEREAS, this Supplemental Indenture is being executed pursuant to the Company’s Offer to Purchase and Consent Solicitation Statement, dated July 16, 2012 (collectively, the “Offer to Purchase”), and the related Letter of Transmittal and Consent;

WHEREAS, Section 9.2 of the Indenture provides that the Company, the Guarantors, the Trustee and the Notes Collateral Agent may amend the Indenture “with the written consent of the Holder or Holders of at least a majority in aggregate principal amount of the outstanding Securities”, subject to certain exceptions specified in Section 9.2 of the Indenture;

WHEREAS, the parties hereto are entering into this Supplemental Indenture to (i) eliminate certain definitions and references to definitions contained in Sections 1.1 and 1.2, respectively, of the Indenture; (ii) amend Sections 3.1 and 3.3 of the Indenture to reduce the required number of days in advance of a redemption date by which notice of a redemption is required to be given by the Company to the Trustee and the Holders; (iii) eliminate certain restrictive covenants contained in Article Four of the Indenture; (iv) eliminate certain conditions to mergers, consolidations and sales of assets contained in Section 5.1 of the Indenture; (v) eliminate certain Events of Default contained in Section 6.1 of the Indenture; and (vi) eliminate all references in the Indenture or the Securities to sections to be eliminated in accordance with the preceding clauses (i), (ii), (iii), (iv) and (v) (collectively, the “Amendments”);

WHEREAS, the Amendments described in the preceding paragraph require the written consent of the Holders of at least a majority in aggregate principal amount of the outstanding Securities;

WHEREAS, the execution and delivery of this Supplemental Indenture and the adoption of the Amendments by the Company, the Guarantors, the Trustee and the Notes Collateral Agent have been authorized by the written consent of the Holders of a majority in aggregate principal amount of the outstanding Securities as of the date hereof; and

WHEREAS, the execution and delivery of this Supplemental Indenture by the Company and the Guarantors have been authorized by resolutions of their Boards of Directors or Managers, and all acts, conditions and requirements necessary to make this Supplemental Indenture a valid and binding agreement in accordance with its terms and for the purposes herein set forth have been done and taken, and the execution and delivery of this Supplemental Indenture have been in all respects duly authorized;

NOW, THEREFORE, in consideration of the above premises, each party hereto agrees, for the benefit of the other parties and for the equal and ratable benefit of the Holders of the Securities, as follows:

SECTION 1.   Definitions.