UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A

(RULE 14a-101)

PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE

SECURITIES EXCHANGE ACT OF 1934

Filed by the Registrant ☒ Filed by a party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary proxy statement

☐ Confidential, for use of the Commission only (as permitted by Rule 14a-6(e)(2))

☐ Definitive proxy statement

☒ Definitive additional materials

☐ Soliciting material pursuant to Sec. 240.14a-12

CECO ENVIRONMENTAL CORP.

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than Registrant)

Payment of filing fee (Check the appropriate box):

☒ No Fee Required

☐ Fee paid previously with preliminary materials:

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11