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

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(Print or Type Responses)

1. Name and Address of Reporting Person * Johansson Peter K. 2. Issuer Name and Ticker or Trading Symbol CECO ENVIRONMENTAL CORP [CECO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) SVP, Chief Financial 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) 16,083 A $ 0 75,703 D Common Stock 03/15/2026 F(2) 4,967 D $54.85 70,736 D Common Stock 03/15/2026 F(2) 1,731 D $54.5 69,005 D Common Stock 03/16/2026 A 3,944 A $ 0 72,949 D Common Stock 03/17/2026 F(2) 1,570 D $57.06 71,379 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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

Restricted Stock Units

(3)

(4)

(4)

Common Stock

47,247

47,247

D

Restricted Stock Units

(3)

(5)

(5)

Common Stock

30,000

30,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Johansson Peter K. 5080 SPECTRUM DRIVE SUITE 800E ADDISON, TX 75001			SVP, Chief Financial Officer

Signatures

/s/ Alyson Gregory as Attorney-in-Fact for Peter Johansson		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)	Represents performance-based restricted stock units. Each restricted stock unit represents a contingent right to receive one share of the Company's stock.
(4)	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.
(5)	Conversion of restricted stock units to the Company's common stock will occur on September 12, 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.
Remarks: Exhibit 24: Power of Attorney

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