Clean Air Act §§ 169A & 169B (42 U.S.C. §§ 7491 & 7492)

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NMED Exh. 1

United States Code Annotated 

Title 42. The Public Health and Welfare

Chapter 85. Air Pollution Prevention and Control (Refs & Annos)

Subchapter I. Programs and Activities

Part C. Prevention of Significant Deterioration of Air Quality

Subpart II. Visibility Protection (Refs & Annos)

42 U.S.C.A. § 7491

§ 7491. Visibility protection for Federal class I areas

Currentness

(a) Impairment of visibility; list of areas; study and report

(1) Congress hereby declares as a national goal the prevention of any future, and the remedying of any existing, impairment 

of visibility in mandatory class I Federal areas which impairment results from manmade air pollution.

(2) Not later than six months after August 7, 1977, the Secretary of the Interior in consultation with other Federal land 

managers shall review all mandatory class I Federal areas and identify those where visibility is an important value of the area. 

From time to time the Secretary of the Interior may revise such identifications. Not later than one year after August 7, 1977, 

the Administrator shall, after consultation with the Secretary of the Interior, promulgate a list of mandatory class I Federal 

areas in which he determines visibility is an important value.

(3) Not later than eighteen months after August 7, 1977, the Administrator shall complete a study and report to Congress on 

available methods for implementing the national goal set forth in paragraph (1). Such report shall include recommendations 

for--

(A) methods for identifying, characterizing, determining, quantifying, and measuring visibility impairment in Federal areas 

referred to in paragraph (1), and

(B) modeling techniques (or other methods) for determining the extent to which manmade air pollution may reasonably be 

anticipated to cause or contribute to such impairment, and

(C) methods for preventing and remedying such manmade air pollution and resulting visibility impairment.

Such report shall also identify the classes or categories of sources and the types of air pollutants which, alone or in 

conjunction with other sources or pollutants, may reasonably be anticipated to cause or contribute significantly to impairment 

of visibility.

(4) Not later than twenty-four months after August 7, 1977, and after notice and public hearing, the Administrator shall 

promulgate regulations to assure (A) reasonable progress toward meeting the national goal specified in paragraph (1), and (B) 

compliance with the requirements of this section.

(b) Regulations
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Regulations under subsection (a)(4) of this section shall--

(1) provide guidelines to the States, taking into account the recommendations under subsection (a)(3) of this section on 

appropriate techniques and methods for implementing this section (as provided in subparagraphs (A) through (C) of such 

subsection (a)(3) ), and

(2) require each applicable implementation plan for a State in which any area listed by the Administrator under subsection 

(a)(2) of this section is located (or for a State the emissions from which may reasonably be anticipated to cause or 

contribute to any impairment of visibility in any such area) to contain such emission limits, schedules of compliance and 

other measures as may be necessary to make reasonable progress toward meeting the national goal specified in subsection 

(a) of this section, including--

(A) except as otherwise provided pursuant to subsection (c) of this section, a requirement that each major stationary 

source which is in existence on August 7, 1977, but which has not been in operation for more than fifteen years as of 

such date, and which, as determined by the State (or the Administrator in the case of a plan promulgated under section 

7410(c) of this title) emits any air pollutant which may reasonably be anticipated to cause or contribute to any 

impairment of visibility in any such area, shall procure, install, and operate, as expeditiously as practicable (and 

maintain thereafter) the best available retrofit technology, as determined by the State (or the Administrator in the case of 

a plan promulgated under section 7410(c) of this title) for controlling emissions from such source for the purpose of 

eliminating or reducing any such impairment, and

(B) a long-term (ten to fifteen years) strategy for making reasonable progress toward meeting the national goal specified 

in subsection (a) of this section.

In the case of a fossil-fuel fired generating powerplant having a total generating capacity in excess of 750 megawatts, 

the emission limitations required under this paragraph shall be determined pursuant to guidelines, promulgated by the 

Administrator under paragraph (1).

(c) Exemptions

(1) The Administrator may, by rule, after notice and opportunity for public hearing, exempt any major stationary source from 

the requirement of subsection (b)(2)(A) of this section, upon his determination that such source does not or will not, by itself 

or in combination with other sources, emit any air pollutant which may reasonably be anticipated to cause or contribute to a 

significant impairment of visibility in any mandatory class I Federal area.

(2) Paragraph (1) of this subsection shall not be applicable to any fossil-fuel fired powerplant with total design capacity of 

750 megawatts or more, unless the owner or operator of any such plant demonstrates to the satisfaction of the Administrator 

that such powerplant is located at such distance from all areas listed by the Administrator under subsection (a)(2) of this 

section that such powerplant does not or will not, by itself or in combination with other sources, emit any air pollutant which 

may reasonably be anticipated to cause or contribute to significant impairment of visibility in any such area.

(3) An exemption under this subsection shall be effective only upon concurrence by the appropriate Federal land manager or 

managers with the Administrator’s determination under this subsection.

(d) Consultations with appropriate Federal land managers

Before holding the public hearing on the proposed revision of an applicable implementation plan to meet the requirements of 

this section, the State (or the Administrator, in the case of a plan promulgated under section 7410(c) of this title) shall consult 

in person with the appropriate Federal land manager or managers and shall include a summary of the conclusions and 

recommendations of the Federal land managers in the notice to the public.
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(e) Buffer zones

In promulgating regulations under this section, the Administrator shall not require the use of any automatic or uniform buffer 

zone or zones.

(f) Nondiscretionary duty

For purposes of section 7604(a)(2) of this title, the meeting of the national goal specified in subsection (a)(1) of this section 

by any specific date or dates shall not be considered a “nondiscretionary duty” of the Administrator.

(g) Definitions

For the purpose of this section--

(1) in determining reasonable progress there shall be taken into consideration the costs of compliance, the time necessary 

for compliance, and the energy and nonair quality environmental impacts of compliance, and the remaining useful life of 

any existing source subject to such requirements;

(2) in determining best available retrofit technology the State (or the Administrator in determining emission limitations 

which reflect such technology) shall take into consideration the costs of compliance, the energy and nonair quality 

environmental impacts of compliance, any existing pollution control technology in use at the source, the remaining useful 

life of the source, and the degree of improvement in visibility which may reasonably be anticipated to result from the use 

of such technology;

(3) the term “manmade air pollution” means air pollution which results directly or indirectly from human activities;

(4) the term “as expeditiously as practicable” means as expeditiously as practicable but in no event later than five years 

after the date of approval of a plan revision under this section (or the date of promulgation of such a plan revision in the 

case of action by the Administrator under section 7410(c) of this title for purposes of this section);

(5) the term “mandatory class I Federal areas” means Federal areas which may not be designated as other than class I under 

this part;

(6) the terms “visibility impairment” and “impairment of visibility” shall include reduction in visual range and atmospheric 

discoloration; and

(7) the term “major stationary source” means the following types of stationary sources with the potential to emit 250 tons 

or more of any pollutant: fossil-fuel fired steam electric plants of more than 250 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 250 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 250 million British thermal units per hour heat input, petroleum storage and transfer 

facilities with a capacity exceeding 300,000 barrels, taconite ore processing facilities, glass fiber processing plants, 

charcoal production facilities.
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CREDIT(S)

(July 14, 1955, c. 360, Title I, § 169A, as added Aug. 7, 1977, Pub.L. 95-95, Title I, § 128, 91 Stat. 742.)

Notes of Decisions (11)

42 U.S.C.A. § 7491, 42 USCA § 7491

Current through P.L. 113-22 (excluding P.L. 113-14) approved 7-25-13
© 2013 Thomson Reuters. No claim to original U.S. Government Works. 5

United States Code Annotated 

Title 42. The Public Health and Welfare

Chapter 85. Air Pollution Prevention and Control (Refs & Annos)

Subchapter I. Programs and Activities

Part C. Prevention of Significant Deterioration of Air Quality

Subpart II. Visibility Protection (Refs & Annos)

42 U.S.C.A. § 7492

§ 7492. Visibility

Currentness

(a) Studies

(1) The Administrator, in conjunction with the National Park Service and other appropriate Federal agencies, shall conduct 

research to identify and evaluate sources and source regions of both visibility impairment and regions that provide 

predominantly clean air in class I areas. A total of $8,000,000 per year for 5 years is authorized to be appropriated for the 

Environmental Protection Agency and the other Federal agencies to conduct this research. The research shall include--

(A) expansion of current visibility related monitoring in class I areas;

(B) assessment of current sources of visibility impairing pollution and clean air corridors;

(C) adaptation of regional air quality models for the assessment of visibility;

(D) studies of atmospheric chemistry and physics of visibility.

(2) Based on the findings available from the research required in subsection (a)(1) of this section as well as other available 

scientific and technical data, studies, and other available information pertaining to visibility source-receptor relationships, the 

Administrator shall conduct an assessment and evaluation that identifies, to the extent possible, sources and source regions of 

visibility impairment including natural sources as well as source regions of clear air for class I areas. The Administrator shall 

produce interim findings from this study within 3 years after November 15, 1990.

(b) Impacts of other provisions

Within 24 months after November 15, 1990, the Administrator shall conduct an assessment of the progress and 

improvements in visibility in class I areas that are likely to result from the implementation of the provisions of the Clean Air 

Act Amendments of 1990 other than the provisions of this section. Every 5 years thereafter the Administrator shall conduct 

an assessment of actual progress and improvement in visibility in class I areas. The Administrator shall prepare a written 

report on each assessment and transmit copies of these reports to the appropriate committees of Congress.

(c) Establishment of visibility transport regions and commissions

(1) Authority to establish visibility transport regions

Whenever, upon the Administrator’s motion or by petition from the Governors of at least two affected States, the 
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Administrator has reason to believe that the current or projected interstate transport of air pollutants from one or more 

States contributes significantly to visibility impairment in class I areas located in the affected States, the Administrator 

may establish a transport region for such pollutants that includes such States. The Administrator, upon the Administrator’s 

own motion or upon petition from the Governor of any affected State, or upon the recommendations of a transport 

commission established under subsection (b) of this section1 may--

(A) add any State or portion of a State to a visibility transport region when the Administrator determines that the 

interstate transport of air pollutants from such State significantly contributes to visibility impairment in a class I area 

located within the transport region, or

(B) remove any State or portion of a State from the region whenever the Administrator has reason to believe that the 

control of emissions in that State or portion of the State pursuant to this section will not significantly contribute to the 

protection or enhancement of visibility in any class I area in the region.

(2) Visibility transport commissions

Whenever the Administrator establishes a transport region under subsection (c)(1) of this section, the Administrator shall 

establish a transport commission comprised of (as a minimum) each of the following members:

(A) the Governor of each State in the Visibility Transport Region, or the Governor’s designee;

(B) The2 Administrator or the Administrator’s designee; and

(C) A2 representative of each Federal agency charged with the direct management of each class I area or areas within the 

Visibility Transport Region.

(3) Ex officio members

All representatives of the Federal Government shall be ex officio members.

(4) Federal Advisory Committee Act

The visibility transport commissions shall be exempt from the requirements of the Federal Advisory Committee Act [5

U.S.C.A. App.].

(d) Duties of visibility transport commissions

A Visibility Transport Commission--

(1) shall assess the scientific and technical data, studies, and other currently available information, including studies 

conducted pursuant to subsection (a)(1) of this section, pertaining to adverse impacts on visibility from potential or 

projected growth in emissions from sources located in the Visibility Transport Region; and

(2) shall, within 4 years of establishment, issue a report to the Administrator recommending what measures, if any, should 

be taken under this chapter to remedy such adverse impacts. The report required by this subsection shall address at least 

the following measures:

(A) the establishment of clean air corridors, in which additional restrictions on increases in emissions may be 
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appropriate to protect visibility in affected class I areas;

(B) the imposition of the requirements of part D of this subchapter affecting the construction of new major stationary 

sources or major modifications to existing sources in such clean air corridors specifically including the alternative siting 

analysis provisions of section 7503(a)(5) of this title; and

(C) the promulgation of regulations under section 7491 of this title to address long range strategies for addressing 

regional haze which impairs visibility in affected class I areas.

(e) Duties of Administrator

(1) The Administrator shall, taking into account the studies pursuant to subsection (a)(1) of this section and the reports 

pursuant to subsection (d)(2) of this section and any other relevant information, within eighteen months of receipt of the 

report referred to in subsection (d)(2) of this section, carry out the Administrator’s regulatory responsibilities under section 

7491 of this title, including criteria for measuring “reasonable progress” toward the national goal.

(2) Any regulations promulgated under section 7491 of this title pursuant to this subsection shall require affected States to 

revise within 12 months their implementation plans under section 7410 of this title to contain such emission limits, schedules 

of compliance, and other measures as may be necessary to carry out regulations promulgated pursuant to this subsection.

(f) Grand Canyon visibility transport commission

The Administrator pursuant to subsection (c)(1) of this section shall, within 12 months, establish a visibility transport 

commission for the region affecting the visibility of the Grand Canyon National Park.

CREDIT(S)

(July 14, 1955, c. 360, Title I, § 169B, as added Nov. 15, 1990, Pub.L. 101-549, Title VIII, § 816, 104 Stat. 2695.)

Notes of Decisions (1)

Footnotes

1

So in original. Words “subsection (b) of this section” probably should be “paragraph (2)”.

2

So in original. Probably should not be capitalized.

42 U.S.C.A. § 7492, 42 USCA § 7492

Current through P.L. 113-22 (excluding P.L. 113-14) approved 7-25-13

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