State authority.

(a) This part shall not be construed to preclude any State or political subdivision thereof from— (1) Adopting and enforcing any emission limiting regulation applicable to a stationary source, provided that such emission limiting regulation is not less stringent than the standards prescribed under this part; or (2) Requiring the owner or operator of a stationary source to obtain permits, licenses, or approvals prior to initiating construction, modification, or operation of the source. [50 FR 46294, Nov. 7, 1985]