(a) The Wyoming plan, as submitted, is approved as meeting the requirements of Part C of the Clean Air Act except that designation of the Savage Run Wilderness Area, as established in Pub. L. 95-237, from Class II to Class I is disapproved.
(b) Regulation for preventing significant deterioration of air quality. The Wyoming plan, as submitted, does not apply to certain sources in the State. Therefore, the provisions of § 52.21 except paragraph (a)(1) are hereby incorporated and made a part of the State implementation plan for the State of Wyoming and are applicable to the following proposed major stationary sources or major modifications:
(1) Sources proposing to construct on Indian Reservations in Wyoming; and
(2) Sources that received an air quality permit from the Wyoming State Department of Environmental Quality prior to September 6, 1979.
(c) The State of Wyoming has clarified the generalized language contained in section 24 of the Wyoming Air Quality Standards and Regulations on the use of the “Guidelines for Air Quality Models.” In a letter to Douglas M. Skie, EPA, dated May 18, 1989, Charles A. Collins, Administrator of the Air Quality Divisions stated:
* * * The Division, will, as a matter of practice, utilize the “Guideline on Air Quality Models” as revised, including Supplement A, in all PSD permit application reviews. The Division will utilize any future revisions to the Guideline in PSD permitting reviews as revisions become effective.
[44 FR 51979, Sept. 6, 1979, as amended at 54 FR 27881, July 3, 1989; 68 FR 11324, Mar. 10, 2003; 68 FR 74491, Dec. 24, 2003]