Clean Harbors (NYSE: CLH) officer reports tax-related share withholding

Rhea-AI Filing Summary

Clean Harbors, Inc. officer Rebecca Underwood, President & EVP Facilities, reported a small tax-related share withholding. On 12/15/2025, 51 shares of common stock were disposed of at $240.71 per share under transaction code “F,” with the explanation stating this represented payment of tax liability by withholding securities upon vesting of equity awards in accordance with Rule 16b-3.

After this transaction, she directly beneficially owns 17,284 shares of Clean Harbors common stock. This reflects a routine insider tax-withholding event rather than an open-market purchase or sale.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Underwood Rebecca

(Last) (First) (Middle)

42 LONGWATER DR

(Street)

NORWELL MA 02061

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
CLEAN HARBORS INC [ CLH ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	PRESIDENT & EVP FACILITIES

3. Date of Earliest Transaction (Month/Day/Year)
12/15/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	12/15/2025		F		51(1)	D	$240.71	17,284	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b3.

	/s/ Rebecca Underwood	12/17/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transaction did Clean Harbors (CLH) report on 12/15/2025?

The report shows a disposition of 51 shares of Clean Harbors common stock on 12/15/2025 at $240.71 per share, recorded under transaction code “F.”

Who is the Clean Harbors insider involved in this filing?

The insider is Rebecca Underwood, who serves as a President & EVP Facilities of Clean Harbors, Inc. She signed the report as the reporting person.

Was the CLH insider transaction an open-market trade?

No. The explanation states the 51 shares were withheld to pay tax liability incident to the vesting of securities, in accordance with Rule 16b-3, rather than sold in an open-market trade.

How many Clean Harbors shares does the insider own after this transaction?

Following the tax-withholding transaction, the reporting person directly beneficially owns 17,284 shares of Clean Harbors common stock.

What does transaction code “F” indicate in this Clean Harbors insider report?

In this report, transaction code “F” is accompanied by an explanation that it reflects payment of tax liability by withholding of securities when equity awards vested, consistent with Rule 16b-3.

Is this Clean Harbors insider report filed by one or multiple reporting persons?

The form indicates it is filed by one reporting person, with the box for “Form filed by One Reporting Person” checked.