Clean Harbors (CLH) executive reports tax withholding and stock forfeiture

Rhea-AI Filing Summary

Clean Harbors executive Rebecca Underwood, President & EVP Facilities, reported two non-market dispositions of common stock tied to equity compensation mechanics.

The filing shows 125 shares withheld to cover tax liabilities upon vesting of stock, and 1,401 restricted shares forfeited because the company did not meet performance targets under its long-term equity incentive program. After these entries, she directly holds 18,684 shares of Clean Harbors common stock.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Underwood Rebecca

Role PRESIDENT & EVP FACILITIES

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	125	$288.93	$36K
Disposition	Common Stock	1,401	$0.00	--

Holdings After Transaction: Common Stock — 20,085 shares (Direct)

Footnotes (1)

1. Payment of tax liability by withholding of securities incident to vesting of securities in accordance with Rule 16b3. Shares of restricted stock forfeited due to the Company not achieving performance targets under its Long Term Equity Incentive Program.

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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)
03/13/2026

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	03/13/2026		F		125(1)	D	$288.93	20,085	D
Common Stock	03/13/2026		D		1,401(2)	D	$0	18,684	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.

2. Shares of restricted stock forfeited due to the Company not achieving performance targets under its Long Term Equity Incentive Program.

	/s/ Rebecca Underwood	03/17/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transactions did Clean Harbors (CLH) report for Rebecca Underwood?

Clean Harbors reported two dispositions by executive Rebecca Underwood. 125 shares were withheld to pay taxes on vested stock, and 1,401 restricted shares were forfeited because performance targets under the company’s long-term equity incentive program were not achieved.

Were the recent Clean Harbors (CLH) insider transactions open-market sales?

The reported transactions were not open-market sales. They involved 125 shares withheld to satisfy tax liabilities on vesting and 1,401 restricted shares forfeited after performance goals were not met under the long-term equity incentive program.

How many Clean Harbors (CLH) shares does Rebecca Underwood hold after the Form 4?

After the reported transactions, Rebecca Underwood directly holds 18,684 shares of Clean Harbors common stock. This balance reflects the tax-withholding of 125 vested shares and the forfeiture of 1,401 restricted shares tied to unmet performance conditions.

Why were 125 Clean Harbors (CLH) shares withheld from Rebecca Underwood?

125 shares were withheld to cover tax liabilities triggered by the vesting of equity awards. This tax-withholding method delivers shares to the issuer instead of cash, satisfying Rule 16b-3 requirements and avoiding an open-market sale by the executive.

Why did Rebecca Underwood forfeit 1,401 Clean Harbors (CLH) shares?

She forfeited 1,401 shares of restricted stock because the company did not achieve performance targets set under its Long Term Equity Incentive Program. When performance conditions are not met, related awards can be canceled without any sale or cash proceeds.