Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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

(Print or Type Responses)

1. Name and Address of Reporting Person * Gleason Todd R 2. Issuer Name and Ticker or Trading Symbol CECO ENVIRONMENTAL CORP [CECO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Executive Officer (Last) (First) (Middle) 5080 SPECTRUM DRIVE, SUITE 800E 3. Date of Earliest Transaction (Month/Day/Year) 03/15/2026 (Street) ADDISON, TX 75001 4. If Amendment, Date 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 (City) (State) (Zip) 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 03/15/2026 A(1) 75,055 A $ 0 482,333 D Common Stock 03/15/2026 F(2) 29,535 D $54.85 452,798 D Common Stock 444 I By first son Common Stock 444 I By second son Common Stock 444 I By third son Common Stock 444 I By daughter

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	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 control number.		SEC 1474 (9-02)

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 Underlying Securities (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 of Derivative Security: 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
Stock Option (right to buy)	$57.06	03/16/2026		A		17,563		(3)	(3)	Common Stock	17,563	$ 0	17,563	D
Stock Option (right to buy)	$6.36							(4)	(4)	Common Stock	316,902		316,902	D
Stock Option (right to buy)	$12.72							(5)	(5)	Common Stock	598,204		598,204	D
Stock Option (right to buy)	$21.31							(6)	(6)	Common Stock	25,446		25,446	D
Stock Option (right to buy)	$23.5							(7)	(7)	Common Stock	67,347		67,347	D
Restricted Stock Units	(8)							(9)	(9)	Common Stock	225,000		225,000	D
Restricted Stock Units	(8)							(10)	(10)	Common Stock	150,000		150,000	D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Gleason Todd R 5080 SPECTRUM DRIVE SUITE 800E ADDISON, TX 75001	X		Chief Executive Officer

Signatures

/s/ Alyson Gregory as Attorney-in-Fact for Todd Gleason		03/17/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Represents performance share units earned.
(2)	Reflects shares withheld for net settlement to cover the tax liability for the vesting of restricted stock units.
(3)	The stock option vests in three equal annual installments beginning on March 16, 2027, and expires on March 16, 2036.
(4)	The stock option vested in four installments beginning on June 6, 2021, and expires on June 6, 2027.
(5)	The stock option vested in four installments beginning on June 6, 2021, and expires on June 6, 2027
(6)	The stock option vests in three equal annual installments beginning on March 15, 2025, and expires on March 15, 2034.
(7)	The stock option vests in three equal annual installments beginning on March 17, 2026, and expires on March 17, 2035.
(8)	Represents performance-based restricted stock units. Each restricted stock unit represents a contingent right to receive one share of the Company's stock.
(9)	Conversion of restricted stock units to the Company's common stock will occur on July 5, 2027 assuming the reporting person is still employed by the Company and if the shares of the Company's common stock have achieved certain stock price targets over the course of the performance period.
(10)	Conversion of restricted stock units to the Company's common stock will occur on June 4, 2029 assuming the reporting person is still employed by the Company and if the shares of the Company's common stock have achieved certain stock price targets over the course of the performance period.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure. Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.