CLH: Financial results

Item 2.02 Results of Operations and Financial Condition On July 29, 2026, Clean Harbors, Inc. (the “Company”) issued a press release announcing the Company’s results of operations for the second quarter ended June 30, 2026. A copy of that press release is furnished with this report as Exhibit 99.1. Item 9.01 Financial Statements and Exhibits. (d) Exhibits. The following exhibits are being furnished herewith: Exhibit No. Description 99.1 Press Release dated July 29, 2026 104 The cover page from this Current Report on Form 8-K, formatted in iXBRL (Inline eXtensible Business Reporting Language) 1 SIGNATURES Pursuant to the requirements of the Securities and Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Clean Harbors, Inc. (Registrant) July 29, 2026 /s/ Eric J. Dugas Executive Vice President and Chief Financial Officer 2