40 CFR § 1090.930 - Reports by auditors.
(a) Attest engagement reports required under subpart S of this part must be submitted by an independent auditor registered with EPA and associated with a company, or companies, through registration under subpart I of this part. Each attest engagement must clearly identify the company and compliance level (e.g., facility), time period, and scope covered by the report. Attest engagement reports covered by this section include those required under this part, and under 40 CFR part 80, subpart M, beginning with the report due June 1, 2022.
(b) An attest engagement report must be submitted to EPA covering each compliance period by June 1 of the following calendar year. The auditor must make the attest engagement available to the company for which it was performed.
(c) The attest engagement must comply with subpart S of this part and the attest engagement report must clearly identify the methodologies followed and any findings, exceptions, and variances.
(d) A single attest engagement submission by the auditor may include procedures performed under this part and under 40 CFR part 80, subpart M. If a single submission method is used, the auditor must clearly and separately describe the procedures and findings for each program.