40 CFR §52.33

1. (a)For the purpose of submitting compliance certifications, nothing in this part or in a plan promulgated by the Administrator shall preclude the use, including the exclusive use, of any credible evidence or information, relevant to whether a source would have been in compliance with applicable requirements if the appropriate performance or compliance test had been performed.
2. (b)For all federal implementation plans, paragraph (a) of this section is incorporated into the plan.