(1) No major stationary source or major modification shall begin actual construction unless, as a minimum, requirements contained in ARM 17.8.819 through 17.8.827 have been met. A major stationary source or major modification exempted from the requirements of subchapter 7 under ARM 17.8.744 or 17.8.745 shall, if applicable, still be required to obtain a Montana air quality permit and comply with all applicable requirements of this subchapter. 

(2) The requirements contained in ARM 17.8.819 through 17.8.827 shall apply to any major stationary source and any major modification with respect to each pollutant subject to regulation under the FCAA that it would emit, except as this subchapter would otherwise allow. This does not include hazardous air pollutants, except to the extent that such hazardous air pollutants are regulated as constituents of more general pollutants listed in section 108(a) (1) of the FCAA, or must be considered in the BACT analysis.

(3) The requirements contained in ARM 17.8.819 through 17.8.827 apply only to any major stationary source or major modification that would be constructed in an area which is designated as attainment or unclassifiable under 40 CFR 81.327, except that the requirements contained in ARM 17.8.819 through 17.8.827 do not apply to a particular major stationary source or major modification if:

(a) the major stationary source would be a nonprofit health or nonprofit educational institution or a major modification that would occur at such an institution; or

(b) the source or modification is a portable stationary source which has previously received a permit under requirements contained in ARM 17.8.819 through 17.8.827, but only if the source proposes to relocate and emissions at the new location would be temporary, the emissions from the source would not exceed its allowable emissions and would impact no Class I area and no area where an applicable increment is known to be violated, and reasonable notice is given to the department prior to the relocation identifying the proposed new location and the probable duration of operation at the new location. Such notice must be given to the department not less than ten days in advance of the proposed relocation unless a different time duration is previously approved by the department.

(c) The source or modification would be a major stationary source or major modification only if fugitive emissions, to the extent quantifiable, are considered in calculating the potential to emit of the stationary source or modification and such source does not belong to any of the following categories:

(i) coal cleaning plants (with thermal dryers) ;

(ii) kraft pulp mills;

(iii) Portland cement plants;

(iv) primary zinc smelters;

(v) iron and steel mills;

(vi) primary aluminum ore reduction plants;

(vii) primary copper smelters;

(viii) municipal incinerators capable of charging more than 250 tons of refuse per day;

(ix) hydrofluoric, sulfuric, or nitric acid plants;

(x) petroleum refineries;

(xi) lime plants;

(xii) phosphate rock processing plants;

(xiii) coke oven batteries;

(xiv) sulfur recovery plants;

(xv) carbon black plants (furnace process) ;

(xvi) primary lead smelters;

(xvii) fuel conversion plants;

(xviii) sintering plants;

(xix) secondary metal production plants;

(xx) chemical process plants;

(xxi) fossil-fuel boilers (or combination thereof) totaling more than 250 million British thermal units per hour heat input;

(xxii) petroleum storage and transfer units with a total storage capacity exceeding 300,000 barrels;

(xxiii) taconite ore processing plants;

(xxiv) glass fiber processing plants;

(xxv) charcoal production plants;

(xxvi) fossil fuel-fired steam electric plants of more than 250 million British thermal units per hour heat input;

(xxvii) any other stationary source category which, as of August 7, 1980, is being regulated under section 111 or 112 of the FCAA.

(4) The requirements contained in ARM 17.8.819 through 17.8.827 do not apply to a major stationary source or major modification with respect to a particular pollutant if the owner or operator demonstrates that, as to that pollutant, the source or modification is located in an area designated as nonattainment under 40 CFR 81.327. 

(5) The requirements contained in ARM 17.8.820, 17.8.822, and 17.8.824 do not apply to a proposed major stationary source or major modification with respect to a particular pollutant, if the allowable emissions of that pollutant from a new source, or the net emissions increase of that pollutant from a modification, would be temporary and impact no Class I area and no area where an applicable increment is known to be violated.

(6) The requirements contained in ARM 17.8.820, 17.8.822, and 17.8.824 as they relate to any maximum allowable increase for a Class II area do not apply to a modification of a major stationary source that was in existence on March 1, 1978, if the net increase in allowable emissions of each pollutant subject to regulation under the FCAA from the modification after the application of BACT would be less than 50 tons per year. This does not include hazardous air pollutants, except to the extent that such hazardous air pollutants are regulated as constituents of more general pollutants listed in section 108(a)(1) of the FCAA.

(7) The department may exempt a proposed major stationary source or major modification from the requirements of ARM 17.8.822, with respect to monitoring for a particular pollutant, if:

(a) the emissions increase of the pollutant from a new stationary source or the net emissions increase of the pollutant from a modification would cause, in any area, air quality impacts less than the following amounts:

(i) carbon monoxide: 575 µg/m³, eight-hour average;

(ii) nitrogen dioxide (NO₂): 14 µg/m³, annual average;

(iii) PM-2.5: 0 µg/m³;

(iv) PM-10: 10 µg/m³, 24-hour average;

(v) sulfur dioxide (SO₂): 13 µg/m³, 24-hour average;

(vi) ozone: no de minimus air quality level is provided for ozone. However, any net increase of 100 tons per year or more of volatile organic compounds or nitrogen oxides subject to this subchapter requires an ambient impact analysis, including the gathering of ambient air quality data;

(vii) lead: 0.1 µg/m³, three-month average;

(viii) fluorides: 0.25 µg/m³, 24-hour average;

(ix) total reduced sulfur: 10 µg/m³, one-hour average;

(x) hydrogen sulfide: 0.2 µg/m³, one-hour average;

(xi) reduced sulfur compounds: 10 µg/m³, one-hour average; or

(b) the concentrations of the pollutant in the area that the source or modification would affect are less than the concentrations listed in (7)(a); or

(c) the pollutant is not listed in (7)(a).