(1) An air quality operating permit may be reopened and revised only under the following circumstances:

(a) Additional applicable requirements under the FCAA become applicable to a major source holding a permit with a remaining term of three or more years. Reopening and revision of the permit shall be completed not later than 18 months after promulgation of the applicable requirement. No reopening is required under this subsection if the effective date of the applicable requirement is later than the date on which the permit is due to expire, unless the original permit or any of its terms and conditions have been extended pursuant to ARM 17.8.1220(12) or 17.8.1221(2) .

(b) Additional requirements (including excess emissions requirements) become applicable to an affected source under the acid rain program. Upon approval by the administrator, excess emissions offset plans shall be deemed to be incorporated into the permit.

(c) The department or the administrator determines that the permit contains a material mistake or that inaccurate statements were made in establishing the emissions standards or other terms or conditions of the permit.

(d) The administrator or the department determines that the permit must be revised or revoked and reissued to assure compliance with the applicable requirements.

(2) Each permit issued under this subchapter shall specify that under the circumstances contained in (1) (a) through (d) , the permit shall be reopened and revised.

(3) Proceedings to reopen and revise an air quality operating permit, including the opportunity for appeal and review by the board, shall follow the same procedures as apply to permit issuance, and shall affect only those parts of the permit for which cause exists for reopening and revision under (1) . Reopening and revision shall be completed as expeditiously as practicable.

(4) The department shall provide a minimum of 90 days advance written notice to the holder of an air quality operating permit of the department's intent to reopen and revise the permit under (1) . The department may, in the notice of intent, request such information as may be necessary to prepare the permit revision for inclusion in the permit after reopening. The notice of intent to reopen may not be appealed to the board. The department's final decision on reopening and revision becomes effective and may be appealed to the board as provided for in ARM 17.8.1210(2) (j) . In an appeal of the department's final decision on reopening, the department shall be required to make a showing of substantial necessity. The permit shield described in ARM 17.8.1214(1) shall remain in effect during any appeal of the department's decision to reopen to the board until such time as the board renders its final decision. Nothing in this section shall limit the emergency powers of the department under the Montana Clean Air Act, Title 75, chapter 2, MCA.