Title 42The Public Health and WelfareRelease 119-73

§7479 Definitions

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

Last updated Apr 6, 2026|Official source

Summary

Defines key words used here and what kinds of sources and actions are covered. It explains what counts as a major emitting facility, when construction is considered to have started, what best available control technology means, and how to set the baseline pollution level. A "major emitting facility" is a list of large industrial sources (for example, big power plants and boilers over 250 million British thermal units per hour, refineries, cement plants, metal smelters, municipal incinerators that take more than 50 tons of refuse per day, petroleum storage over 300,000 barrels, and similar plants) that emit or could emit 100 tons per year or more of any pollutant, and it also covers any other source with the potential to emit 250 tons per year or more; new or modified nonprofit health or education facilities are excluded if the State has exempted them. "Commenced" means the owner has all required preconstruction permits and has either begun continuous on-site construction or signed binding contracts that force construction to proceed. "Necessary preconstruction approvals or permits" are the permits the permitting authority requires before starting work. "Construction" also includes modifying an existing source. "Best available control technology" is a case-by-case emission limit requiring the maximum pollution reduction achievable for each regulated pollutant, set after considering energy, environmental, and economic effects; it can include cleaner fuels or treatment methods, must not let emissions exceed any applicable air-quality standards, and cannot allow emissions to rise above levels that would have been required before November 15, 1990 when using clean fuels. "Baseline concentration" is the ambient pollution level when the first permit application is filed in an area, based on EPA or State data and required monitoring; it must count emissions from major sources whose construction began before January 6, 1975 but were not yet operating, while sulfur oxides and particulate emissions from sources that began construction after January 6, 1975 are excluded from the baseline and instead counted against allowed 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 42The Public Health and Welfare

Last Updated

Apr 6, 2026

Release point: 119-73