Item 7.01 Regulation FD Disclosure On June 9, 2026, CECO Environmental Corp. issued a press release announcing the updated outlook for its full year 2026, reflective of the acquisition of Thermon Group Holdings, Inc. A copy of the press release is furnished as Exhibit 99.1 to this report and is incorporated herein by reference. The information under Item 7.01 of this Current Report on Form 8-K (including Exhibit 99.1) is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “ Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits. (d) Exhibits Exhibit No. Description 99.1 Press Release, dated June 9, 2026, furnished herewith. ───────────────────────────────────────────────────────────────────────────────────────────────── 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: June 9, 2026 CECO Environmental Corp. ────────────────────────────────────────────────────────────────────────────────── By: /s/ Kiril Kovachev Kiril Kovachev Chief Accounting Officer