Ill. Admin. Code tit. 35 § 201.161
The Agency may impose such conditions in an operating permit as may be necessary to accomplish the purposes of the Act, and as are not inconsistent with the regulations promulgated by the Board thereunder. Except as herein specified, nothing in this Chapter shall be deemed to limit the power of the Agency in this regard. When deemed appropriate as a condition to the issuance of an operating permit, the Agency may require that the permittee adequately maintain the air pollution control equipment covered by the permit. To assure that such a maintenance program is planned, the Agency may require that the permittee have a maintenance program and keep such maintenance records as are necessary to demonstrate compliance with this rule; provided, however, the Agency shall not have the authority to approve the maintenance programs required thereunder.
Ill. Admin. Code tit. 35, § 201.161