17.8.825    SOURCES IMPACTING FEDERAL CLASS I AREAS--ADDITIONAL REQUIREMENTS

(1) The department shall transmit to the administrator a copy of each permit application relating to a major stationary source or major modification and provide notice to the administrator of every action related to the consideration of such permit.

(2) The federal land manager and the federal official charged with direct responsibility for management of Class I lands have an affirmative responsibility to protect the air quality related values (including visibility) of any such lands and to consider, in consultation with the administrator, whether a proposed source or modification would have an adverse impact on such values.

(3) Federal land managers with direct responsibility for management of Class I lands may present to the department, after reviewing the department's preliminary determination required under ARM 17.8.759, a demonstration that the emissions from the proposed source or modification would have an adverse impact on the air quality-related values (including visibility) of any federal mandatory Class I lands, notwithstanding that the change in air quality resulting from emissions from such source or modification would not cause or contribute to concentrations which would exceed the maximum allowable increases for a Class I area. If the department concurs with such demonstration, the department may not issue the permit.

(4) The owner or operator of a proposed source or modification may demonstrate to the federal land manager that the emissions from such source would have no adverse impact on the air quality-related values of such lands (including visibility), notwithstanding that the change in air quality resulting from emissions from such source or modification would cause or contribute to concentrations which would exceed the maximum allowable increases for a Class I area. If the federal land manager concurs with such demonstration and so certifies to the department, the department may, provided that applicable requirements are otherwise met, issue the permit with such emission limitations as may be necessary to assure that emissions of sulfur dioxide (SO₂), particulate matter, and nitrogen oxides would not exceed the following maximum allowable increases over the minor source baseline concentration for such pollutants:

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Pollutant

Maximum allowable increase (micrograms per cubic meter)

PM-2.5
�����������annual arithmetic mean..........................................................................................4
�����������24-hr maximum........................................................................................................9
Particulate matter:
�����������PM-10, annual arithmetic mean...........................................................................17
�����������PM-10, 24-hr maximum.........................................................................................30
Sulfur dioxide (SO₂):
�����������annual arithmetic mean.........................................................................................20
�����������24-hr maximum......................................................................................................91
�����������3-hr maximum......................................................................................................325
Nitrogen dioxide (NO₂):
�����������annual arithmetic mean.........................................................................................25
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(5) The owner or operator of a proposed source or modification which cannot be approved under procedures developed pursuant to (4) may seek to obtain a sulfur dioxide variance from the Governor.

(a) The owner or operator of a proposed source or modification must demonstrate to the Governor that the source or modification cannot be constructed by reason of any maximum allowable increase for sulfur dioxide for periods of 24 hours or less applicable to any Class I area and, in the case of federal mandatory Class I areas, that a variance under this clause would not adversely affect the air quality-related values of the area (including visibility).

(b) The Governor, after consideration of the federal land manager's recommendation (if any) and subject to the concurrence of the federal land manager, may grant, after notice and an opportunity for a public hearing, a variance from such maximum allowable increase.

(c) If the federal land manager does not concur in the Governor's recommendations, the recommendations of the Governor and the federal land manager shall be transferred to the President, and the President may approve the Governor's recommendation if the President finds that such variance is in the national interest.

(d) If such a variance is granted under this rule, the department may issue a permit to such source or modification in accordance with provisions developed pursuant to (6), provided that the applicable requirements of the plan are otherwise met.

(6) In the case of a permit issued under procedures developed pursuant to (5), the source or modification shall comply with emission limitations as may be necessary to assure that emissions of sulfur dioxide from the source or modification would not (during any day on which the otherwise applicable maximum allowable increases are exceeded) cause or contribute to concentrations which would exceed the following maximum allowable increases over the baseline concentration and to assure that such emissions would not cause or contribute to concentrations which exceed the otherwise applicable maximum allowable increases for periods of exposure of 24 hours or less for more than 18 days, not necessarily consecutive, during any annual period:

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MAXIMUM ALLOWABLE INCREASE
[Micrograms per cubic meter]

	Terrain Areas
PERIODS OF EXPOSURE	Low	High
24-hr maximum................................................................................................................	36	62
3-hr maximum..................................................................................................................	130	221

History: 75-2-111, 75-2-203, MCA; IMP, 75-2-202, 75-2-203, 75-2-204, MCA; NEW, 1993 MAR p. 2919, Eff. 12/10/93; AMD, 1994 MAR p. 2829, Eff. 10/28/94; TRANS, from DHES, 1996 MAR p. 2285; AMD, 2002 MAR p. 3567, Eff. 12/27/02; AMD, 2011 MAR p. 2134, Eff. 10/14/11.