CECO ENVIRONMENTAL CORP

Pursuant to the requirements of Section 13 or 15(d) 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.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated:

Principal Executive Officer:

Report of Independent Registered Public Accounting Firm

Shareholders and Board of Directors

Dallas, Texas

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated balance sheets of CECO Environmental Corp. (the “Company”) as of December 31, 2024 and 2023, the related consolidated statements of income, comprehensive income, shareholders’ equity, accumulated other comprehensive loss and cash flows for each of the three years in the period ended December 31, 2024, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024, in conformity with accounting principles generally accepted in the United States of America.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the Company's internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) and our report dated February 25, 2025 expressed an unqualified opinion thereon.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s consolidated financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of a critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing separate opinions on the critical audit matter or on the accounts or disclosures to which it relates.

Over Time Revenue Recognition Using the Cost-to-Cost Measure

As described in Notes 1 and 15 to the Company’s consolidated financial statements, the Company derives a significant portion of its revenues from fixed-price contracts within the Engineered Systems and Industrial Process Solutions segments. The revenue for such contracts is recognized over a period of time based on the extent of progress towards completion of the performance obligation, which is measured based on the ratio of costs incurred to date to total estimated costs to complete the performance obligation. Changes in these estimates can have a material impact on the amount of revenue recognized each period.

We identified the accuracy of revenue recognized over time for open contracts as a critical audit matter. The determination of estimated cost and progress to completion requires management to make significant estimates and assumptions, which includes an analysis of total estimated labor, material and subcontract costs, historical experience, current performance to date and the conditions to complete each contract. This analysis requires significant management judgment, which affects the amount of revenue recognized by the Company. Auditing these complex judgments and assumptions involves especially challenging auditor judgment due to the nature and extent of audit evidence available and effort required to address these matters.

The primary procedures we performed to address this critical audit matter included:

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Testing the design and operating effectiveness of internal controls for the Industrial Process Solutions segment related to the determination of estimated costs to complete a project, including the monthly review of open over time projects and review of estimated cost calculations to complete open projects. These controls include the review of the reasonableness of the assumptions used and the appropriateness of methodologies used to determine costs to complete.

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Testing the completeness, existence, and accuracy of estimated costs and progress to completion calculations for a sample of open contracts by validating the underlying project data and assumptions used as inputs through the inspection of relevant source documents including contracts, project plans or budgets and activity reports, invoices of costs incurred to date, results of recent similar historical projects, other third-party subcontractor support, inquiry of project managers, and confirmations.

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Evaluating management’s ability to estimate costs and progress to completion by performing a retrospective review on a sample basis of estimated project costs to actual project costs for completed contracts and investigating variances outside of predetermined thresholds through the inspection of relevant source documents.

/s/ BDO USA, P.C.

We have served as the Company's auditor since 2008.

Cincinnati, Ohio

February 25, 2025