25 Pa. Code § 141.1
The Department may by order impose standards more stringent than those set forth in this article for a source or class of sources, upon the petition of a person or upon its own motion, if one of the following applies:
The provisions of this § 141.1 adopted March 3, 1972, effective March 20, 1972, 2 Pa.B. 383; amended May 13, 1988, effective May 14, 1988, 18 Pa.B. 2204. Immediately preceding text appears at serial pages (84600) and (99187).
This section cited in 25 Pa. Code § 264.343 (relating to performance standards).