Title 42, The Public Health and WelfareRelease 119-102

§7479 Definitions

Title 42 › CHAPTER 85 — AIR POLLUTION PREVENTION AND CONTROL › SUBCHAPTER I — PROGRAMS AND ACTIVITIES › Part C — Prevention of Significant Deterioration of Air Quality › subpart i — clean air › § 7479

Last updated Aug 21, 2026|Official source

Summary

Defines key words used for permits and pollution limits in this part. "Major emitting facility" means big stationary polluters. For a long list of industrial types (like large steam electric plants, refineries, cement plants, smelters, big boilers, municipal incinerators over 50 tons/day, petroleum storage over 300,000 barrels, and others) the threshold is 100 tons per year of any pollutant. Any other source that can emit 250 tons per year or more also counts. New or changed nonprofit health or education facilities that a State has exempted are not included. "Commenced" means the owner got all required preconstruction permits and either started continuous on-site building or signed binding contracts that will finish construction in a reasonable time. "Necessary preconstruction approvals or permits" are whatever the permitting authority requires before starting. "Construction" also covers modifications as defined in 7411(a). "Best available control technology" (BACT) is the strict pollution limit the permitting authority sets case-by-case, considering energy, environment, and cost, using available methods (like cleaner fuels or treatment); BACT cannot allow emissions above standards set under sections 7411 or 7412, and using clean fuels to comply cannot raise emissions above levels required before November 15, 1990. "Baseline concentration" is the ambient pollutant level when the first permit is applied for, based on EPA or State data and required monitoring; it must count projected emissions from major facilities that began construction before January 6, 1975 but were not yet operating, while sulfur oxides and particulate emissions from facilities that began construction after January 6, 1975 are excluded from the baseline and counted against allowable increases.

Full Legal Text

Title 42, §7479

The Public Health and Welfare, Source: USLM XML via OLRC

For purposes of this part—
(1)The term “major emitting facility” means any of the following stationary sources of air pollutants which emit, or have the potential to emit, one hundred tons per year or more of any air pollutant from the following types of stationary sources: fossil-fuel fired steam electric plants of more than two hundred and fifty million British thermal units per hour heat input, coal cleaning plants (thermal dryers), kraft pulp mills, Portland Cement plants, primary zinc smelters, iron and steel mill plants, primary aluminum ore reduction plants, primary copper smelters, municipal incinerators capable of charging more than fifty tons of refuse per day, hydrofluoric, sulfuric, and nitric acid plants, petroleum refineries, lime plants, phosphate rock processing plants, coke oven batteries, sulfur recovery plants, carbon black plants (furnace process), primary lead smelters, fuel conversion plants, sintering plants, secondary metal production facilities, chemical process plants, fossil-fuel boilers of more than two hundred and fifty million British thermal units per hour heat input, petroleum storage and transfer facilities with a capacity exceeding three hundred thousand barrels, taconite ore processing facilities, glass fiber processing plants, charcoal production facilities. Such term also includes any other source with the potential to emit two hundred and fifty tons per year or more of any air pollutant. This term shall not include new or modified facilities which are nonprofit health or education institutions which have been exempted by the State.
(2)(A)The term “commenced” as applied to construction of a major emitting facility means that the owner or operator has obtained all necessary preconstruction approv­als or permits required by Federal, State, or local air pollution emissions and air quality laws or regulations and either has (i) begun, or caused to begin, a continuous program of physical on-site construction of the facility or (ii) entered into binding agreements or contractual obligations, which cannot be canceled or modified without substantial loss to the owner or operator, to undertake a program of construction of the facility to be completed within a reasonable time.
(B)The term “necessary preconstruction approvals or permits” means those permits or approvals, required by the permitting authority as a precondition to undertaking any activity under clauses (i) or (ii) of subparagraph (A) of this paragraph.
(C)The term “construction” when used in connection with any source or facility, includes the modification (as defined in section 7411(a) of this title) of any source or facility.
(3)The term “best available control technology” means an emission limitation based on the maximum degree of reduction of each pollutant subject to regulation under this chapter emitted from or which results from any major emitting facility, which the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such facility through application of production processes and available methods, systems, and techniques, including fuel cleaning, clean fuels, or treatment or innovative fuel combustion techniques for control of each such pollutant. In no event shall application of “best available control technology” result in emissions of any pollutants which will exceed the emissions allowed by any applicable standard established pursuant to section 7411 or 7412 of this title. Emissions from any source utilizing clean fuels, or any other means, to comply with this paragraph shall not be allowed to increase above levels that would have been required under this paragraph as it existed prior to November 15, 1990.
(4)The term “baseline concentration” means, with respect to a pollutant, the ambient concentration levels which exist at the time of the first application for a permit in an area subject to this part, based on air quality data available in the Environmental Protection Agency or a State air pollution control agency and on such monitoring data as the permit applicant is required to submit. Such ambient concentration levels shall take into account all projected emissions in, or which may affect, such area from any major emitting facility on which construction commenced prior to January 6, 1975, but which has not begun operation by the date of the baseline air quality concentration determination. Emissions of sulfur oxides and particulate matter from any major emitting facility on which construction commenced after January 6, 1975, shall not be included in the baseline and shall be counted against the maximum allowable increases in pollutant concentrations established under this part.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

Amendments

1990—Par. (1). Pub. L. 101–549, § 305(b), struck out “two hundred and” after “municipal incinerators capable of charging more than”. Par. (3). Pub. L. 101–549, § 403(d), directed the insertion of “, clean fuels,” after “including fuel cleaning,”, which was executed by making the insertion after “including fuel cleaning” to reflect the probable intent of Congress, and inserted at end “Emissions from any source utilizing clean fuels, or any other means, to comply with this paragraph shall not be allowed to increase above levels that would have been required under this paragraph as it existed prior to November 15, 1990.” 1977—Par. (2)(C). Pub. L. 95–190 added subpar. (C).

Statutory Notes and Related Subsidiaries

Study of Major Emitting Facilities With Potential of Emitting 250 Tons Per Year Pub. L. 95–95, title I, § 127(b), Aug. 7, 1977, 91 Stat. 741, directed Administrator, within 1 year after Aug. 7, 1977, to report to Congress on consequences of that portion of definition of “major emitting facility” under this subpart which applies to facilities with potential to emit 250 tons per year or more.

Reference

Citations & Metadata

Citation

42 U.S.C. § 7479

Title 42, The Public Health and Welfare

Last Updated

Aug 21, 2026

Release point: 119-102