Rule 17.8.301 - DEFINITIONS For purposes of this subchapter, the following definitions apply:
(1) "112(g) exemption" means a document issued by the department on a case-by-case basis, finding that a major source of HAP meets the criteria contained in 40 CFR 63.41 (definition of "construct a major source", (2) (i) through (vi)), and is thus exempt from the requirements of 42 USC 7412 (g).(2) "Airborne particulate matter" means any particulate matter discharged into the outdoor atmosphere which is not discharged from the normal exit of a stack or chimney for which a source test can be performed in accordance with 40 CFR Part 60, Appendix A, method 5 (determination of particulate emissions from stationary sources).(3) "Best available control technology (BACT) " means an emission limitation (including a visible emission standard), based on the maximum degree of reduction for each air pollutant which would be emitted from any source or alteration which the department, on a case-by-case basis, taking into account energy, environment, and economic impacts and other costs, determines is achievable for such sources or alterations through application of production processes or available methods, systems, and techniques, including fuel cleaning or treatment or innovative fuel combustion techniques for control of such air contaminant. In no event shall application of BACT result in emission of any air contaminant which would exceed the emissions allowed by any applicable standard under this chapter. If the department determines that technological or economic limitations on the application of measurement methodology to a particular class of sources or alterations would make the imposition of an emission standard infeasible, it may instead prescribe a design, equipment, work practice or operational standard or combination thereof, to require the application of BACT. Such standard shall, to the degree possible, set forth the emission reduction achievable by implementation of such design, equipment, work practice or operation and shall provide for compliance by means which achieve equivalent results.(4) "Beginning actual construction" means, in general, initiation of physical on-site construction activities of a permanent nature. Such activities include, but are not limited to, installation of building supports and foundations, laying of underground pipework, and construction of permanent storage structures.(5) "Building, structure, facility, or installation" means all of the pollutant-emitting activities which belong to the same industrial grouping, are located on one or more contiguous or adjacent properties, and are under the control of the same person (or persons under common control) except the activities of any vessel. Pollutant-emitting activities shall be considered as part of the same industrial grouping if they belong to the same major group (i.e., which have the same two-digit code) as described in the standard industrial classification manual, 1987 or the North American Industry Classification System of 2022 at https://www.census.gov/naics/.(6) "Construct a major source of HAP" means: (a) to fabricate, erect, or install a major source of HAP; or(b) to reconstruct a major source of HAP, by replacing components at an existing process or production unit that in and of itself emits or has the potential to emit ten tons per year of any HAP, or 25 tons per year of any combination of HAP, whenever: (i) the fixed capital cost of the new components exceeds 50% of the fixed capital cost that would be required to construct a comparable process or production unit; and(ii) it is technically and economically feasible for the reconstructed major source to meet the applicable maximum achievable control technology emission limitation for new sources established under 40 CFR 63 Subpart B.(7) "Existing fuel burning equipment" means fuel burning equipment constructed or installed prior to November 23, 1968.(8) "Greenfield site" means a contiguous area under common control that is an undeveloped site.(9) "Hazardous air pollutant" ("HAP") means any air pollutant listed in or pursuant to 42 USC 7412 (b).(10) "Lowest achievable emission rate" ("LAER") means, for any source, that rate of emissions which reflects: (a) the most stringent emission limitation which is contained in the implementation plan of any state for such class or category of source, unless the owner or operator of the proposed source demonstrates that such limitations are not achievable; or(b) the most stringent emission limitation which is achieved in practice by such class or category of source, whichever is more stringent. In no event shall the application of this term permit a proposed new or modified source to emit any pollutant in excess of the amount allowable under applicable new source standards of performance under 40 CFR Parts 60 and 61.(11) "Major source of HAP" means: (a) at any greenfield site, a stationary source or group of stationary sources which is located within a contiguous area and under common control and which emits or has the potential to emit ten tons per year of any HAP or 25 tons per year of any combination of HAP; or(b) at any developed site, a new process or production unit which in and of itself emits or has the potential to emit ten tons per year of any HAP or 25 tons per year of any combination of HAP.(12) "Maximum achievable control technology" ("MACT") means the emission limitation which is not less stringent than the emission limitation achieved in practice by the best controlled similar source, and which reflects the maximum degree of reduction in emissions that the department, taking into consideration the cost of achieving such emission reduction, and any nonair quality health and environmental impacts and energy requirements, determines is achievable by the constructed or reconstructed major source of HAP.(13) "New fuel burning equipment" means fuel burning equipment constructed, installed or altered after November 23, 1968.(14) "Notice of MACT approval" means a document issued by the department containing all federally enforceable conditions necessary to enforce MACT or other control technologies such that the MACT emission limitation is met.(15) "Process or production unit" means any collection of structures and/or equipment, that processes, assembles, applies, or otherwise uses material inputs to produce or store an intermediate or final product. A single facility may contain more than one process or production unit.(16) "Process weight" means the total weight of all materials introduced into any specific process which may cause emissions. Solid fuels charged will be considered as part of the process weight, but liquid and gaseous fuels and combustion air will not.(17) "Process weight rate" means the rate established as follows: (a) for continuous or long-run steady-state operations, the total process weight for the entire period of continuous operation or for a typical portion thereof, divided by the number of hours of such period or portion thereof;(b) for cyclical or batch operations, the total process weight for a period that covers a complete operation or an integral number of cycles, divided by the hours of actual process operation during such a period. Where the nature of any process or operation or the design of any equipment is such as to permit more than one interpretation of this definition, the interpretation that results in the minimum value for allowable emissions shall apply.(18) "Reasonable precautions" mean any reasonable measures to control emissions of airborne particulate matter. Determination of what is reasonable will be accomplished on a case-by-case basis taking into account energy, environmental, economic, and other costs.(19) "Reasonably available control technology" means devices, systems, process modifications, or other apparatus or techniques that are determined on a case-by-case basis to be reasonably available, taking into account the necessity of imposing such controls in order to attain and maintain a national or Montana ambient air quality standard, the social, environmental, and economic impact of such controls, and alternative means of providing for attainment and maintenance of such standard.NEW, 1993 MAR p. 2530, Eff. 10/29/93; TRANS, from DHES, 1996 MAR p. 2285; AMD, 1999 MAR p. 1658, Eff. 7/23/99; AMD, 2001 MAR p. 976, Eff. 6/8/01; AMD, 2008 MAR p. 2267, Eff. 10/24/08; AMD, 2024 MAR p. 2056, Eff. 8/24/2024AUTH: 75-2-112, 75-2-203, MCA; IMP: 75-2-203, MCA