United States securities and exchange commission logo May 9, 2022 Matthew Eckl Chief Financial Officer CECO Environmental Corp. 14651 North Dallas Parkway, Suite 500 Dallas, Texas 75254 Re: CECO Environmental Corp. Registration Statement on Form S-3 Filed May 2, 2022 File No. 333-264623 Dear Mr. Eckl: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Matthew Crispino, Staff Attorney, at (202) 551-3456 or Jan Woo, Legal Branch Chief, at (202) 551-3453 with any questions. Sincerely, Division of Corporation Finance Office of Technology cc: Amy S. Chen