FUEL TECH, INC. 10-Q

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds None Item 6. Exhibits a. Exhibits (all filed herewith) 31.1 Certification of CEO pursuant to Section 302 of Sarbanes-Oxley Act of 2002 31.2 Certification of principal financial officer pursuant to Section 302 of Sarbanes-Oxley Act of 2002 32 Certification of CEO and principal financial officer pursuant to Section 906 of Sarbanes-Oxley Act of 2002 101.1 Inline INSXBRL Instance Document - The Instance Document does not appear in the Interactive Data File because its Inline XBRL tags are embedded within the Inline XBRL document. 101.2 Inline SCHXBRL Taxonomy Extension Schema Document 101.3 Inline CALXBRL Taxonomy Extension Calculation Linkbase Document 101.4 Inline DEFXBRL Taxonomy Extension Definition Linkbase Document 101.5 Inline LABXBRL Taxonomy Extension Label Linkbase Document 101.6 Inline PREXBRL Taxonomy Extension Prevention Linkbase Document 104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) 18 Table of Contents FUEL TECH, INC. 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 thereunto duly authorized. Date: May 12, 2025 By: /s/ Vincent J. Arnone Vincent J. Arnone President and Chief Executive Officer (Principal Executive Officer) Date: May 12, 2025 By: /s/ Ellen T. Albrecht Ellen T. Albrecht Vice President, Chief Financial Officer and Treasurer (Principal Financial Officer) 19