CLEAN HARBORS INC — Board/Management Information 2026

May 20, 2026

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 19, 2026

CLEAN HARBORS, INC .

(Exact name of registrant as specified in its charter)

Massachusetts	001-34223	04-2997780
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

42 Longwater Drive	02061-9149
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s telephone number, including area code ( 781 ) 792-5000

Not Applicable

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol	Name of each exchange on which registered
Common Stock, $0.01 par value	CLH	New York Stock Exchange

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On May 19, 2026, Alan S. McKim, serving in the capacities of Executive Chairman of the Board of Directors (the “Board”) and Chief Technology Officer, notified the Board of his intention to retire from the Board and his role as Chief Technology Officer, effective upon the Board’s appointment of a new Chairman. The appointment of an independent Chairman is anticipated to occur in the summer of 2026, as part of a planned leadership transition. Mr. McKim’s decision to retire from the Board and his role as Chief Technology Officer does not arise from, nor is it attributable to, any disagreement with the Company with respect to any matter pertaining to the Company's operations, policies, practices, or otherwise.

Item 7.01 Regulation FD Disclosure.

On May 20, 2026, the Company issued a press release announcing Mr. McKim’s retirement. A copy of the press release is furnished as Exhibit 99.1 hereto.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit Number	Description
99.1	Press Release dated May 20, 2026 (furnished herewith)
104	The cover page to this Current Report on Form 8-K, formatted in iXBRL (Inline eXtensible Business Reporting Language)

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)
May 20, 2026	/s/ Eric J. Dugas
	Executive Vice President and Chief Financial Officer