Ill. Admin. Code tit. 35 § 201.245
The approval of a compliance program and project completion schedule shall be a condition precedent to the issuance and effectiveness of a permit pursuant to Subpart D. An approved compliance program and project completion schedule, and full compliance therewith, and a current operating permit, shall be a prima facie defense to any enforcement action alleging a violation of the standards or limitations set forth in Subchapter c of this Chapter with respect to any air contaminant included in such program and schedule during the period of the program. Failure to adhere to an approved compliance schedule shall constitute a violation of this Part for which appropriate sanctions may be sought in accordance with the Act.
Ill. Admin. Code tit. 35, § 201.245