40 CFR § 68.58 - Compliance audits.
(a) The owner or operator shall certify that they have evaluated compliance with the provisions of this subpart at least every three years to verify that the procedures and practices developed under this subpart are adequate and are being followed.
(b) The compliance audit shall be conducted by at least one person knowledgeable in the process.
(c) The owner or operator shall develop a report of the audit findings.
(d) The owner or operator shall promptly determine and document an appropriate response to each of the findings of the compliance audit and document that deficiencies have been corrected.
(e) The owner or operator shall retain the two (2) most recent compliance audit reports. This requirement does not apply to any compliance audit report that is more than five years old.