Clean Air Act: A Summary of the Act and Its Major Requirements

Clean Air Act: A Summary of the Act
and Its Major Requirements
Updated November 26, 2008
James E. McCarthy, Coordinator,
Claudia Copeland, Larry Parker,
and Linda-Jo Schierow
Specialists in Environmental, Resources, and Energy Policy
Resources, Science, and Industry Division

Clean Air Act: A Summary of the Act
and Its Major Requirements
This report summarizes the Clean Air Act and its major regulatory requirements.
It excerpts, with minor modifications, the Clean Air Act chapter of CRS Report
RL30798, which summarizes a dozen environmental statutes that form the basis for
the programs of the Environmental Protection Agency. This report will be updated
at the end of each Congress, or sooner if Congress enacts a law that substantively
changes the statute.
The principal statute addressing air quality concerns, the Clean Air Act was first
enacted in 1955, with major revisions in 1970, 1977, and 1990. The Act requires
EPA to set health-based standards for ambient air quality, sets deadlines for the
achievement of those standards by state and local governments, and requires EPA to
set national emission standards for large or ubiquitous sources of air pollution,
including motor vehicles, power plants, and other industrial sources. In addition, the
Act mandates emission controls for sources of 188 hazardous air pollutants, requires
the prevention of significant deterioration of air quality in areas with clean air,
requires a program to restore visibility impaired by regional haze in national parks
and wilderness areas, and implements the Montreal Protocol to phase out most
ozone-depleting chemicals.
This report describes the Act’s major provisions and provides tables listing all
major amendments, with the year of enactment and Public Law number, and cross-
referencing sections of the Act with the major U.S. Code sections of the codified

In troduction ..................................................1
Overview ....................................................1
National Ambient Air Quality Standards............................3
State Implementation Plans......................................4
Nonattainment Requirements.....................................4
Requirements for Ozone Nonattainment Areas...................5
Requirements for Carbon Monoxide Nonattainment Areas.........7
Requirements for Particulate Nonattainment Areas................8
Emission Standards for Mobile Sources............................8
Hazardous Air Pollutants.......................................10
New Source Performance Standards..............................12
Solid Waste Incinerators.......................................12
Prevention of Significant Deterioration / Regional Haze..............13
Acid Deposition Control.......................................14
Permits .....................................................15
Enforcement .................................................16
Stratospheric Ozone Protection..................................17
Selected References...........................................18
List of Tables
Table 1. Clean Air Act and Amendments...............................2
Table 2. Ozone Nonattainment Classifications...........................5
Table 3. Major U.S. Code Sections of the Clean Air Act..................18

Clean Air Act: A Summary of the Act
and Its Major Requirements
The authorities and responsibilities of the Environmental Protection Agency
(EPA) derive primarily from a dozen major environmental statutes. This report
provides a concise summary of one of those statutes, the Clean Air Act. It provides
a very brief history of federal involvement in air quality regulation and of the
provisions added by legislation in 1970, 1977, and 1990; it explains major authorities
contained in the Act; it defines key terms; and it lists references for more detailed
information on the Act and its implementation.
While this report attempts to present the essence of the Act, it is necessarily
incomplete. Many details and secondary provisions are omitted. In addition, the
report describes the statute largely without discussing its implementation. Statutory
deadlines to control emissions and achieve particular mandates have often been
missed as a result of delayed standard-setting by EPA, delayed action on
implementation by states and local governments, or law suits brought by interested
parties. Other CRS products, including CRS Report RL33776 (Clean Air Act Issues
in the 110th Congress: Implementation and Oversight) and more than a dozen CRS
reports discuss implementation concerns and current issues. Readers interested in a
more comprehensive discussion of the history of the Act are referred to CRS Report
83-34 ENR, Environmental Protection: An Historical Review of the Legislation and
Programs of the Environmental Protection Agency (available from James E.
The Clean Air Act, codified as 42 U.S.C. 7401 et seq., seeks to protect human
health and the environment from emissions that pollute ambient, or outdoor, air. It
requires the Environmental Protection Agency to establish minimum national
standards for air quality, and assigns primary responsibility to the states to assure
compliance with the standards. Areas not meeting the standards, referred to as
“nonattainment areas,” are required to implement specified air pollution control
measures. The Act establishes federal standards for mobile sources of air pollution
and their fuels, for sources of 188 hazardous air pollutants, and for the emissions that
cause acid rain. It establishes a comprehensive permit system for all major sources
of air pollution. It also addresses the prevention of pollution in areas with clean air
and protection of the stratospheric ozone layer.

Table 1. Clean Air Act and Amendments
(codified generally as 42 U.S.C. 7401-7671)
YearActPublic Law Number
1955Air Pollution Control ActP.L. 84-159
1959ReauthorizationP.L. 86-353
1960Motor vehicle exhaust studyP.L. 86-493
1963Clean Air Act AmendmentsP.L. 88-206
1965Motor Vehicle Air Pollution Control ActP.L. 89-272, Title I
1966Clean Air Act Amendments of 1966P.L. 89-675
1967Air Quality Act of 1967
National Air Emission Standards ActP.L. 90-148
1970Clean Air Act Amendments of 1970P.L. 91-604
1973ReauthorizationP.L. 93-13
1974Energy Supply and Environmental Coordination
Act of 1974P.L. 93-319
1977Clean Air Act Amendments of 1977P.L. 95-95
1980Acid Precipitation Act of 1980P.L. 96-294, Title VII
1981Steel Industry Compliance Extension Act of 1981P.L. 97-23
1987Clean Air Act 8-month ExtensionP.L. 100-202
1990Clean Air Act Amendments of 1990P.L. 101-549

1995-96Relatively minor laws amending the ActP.L. 104-6, 59, 70,

1999Chemical Safety Information, Site Security and
Fuels Regulatory Relief ActP.L. 106-40

2004Amendments to §209 re small enginesP.L. 108-199,

Division G, Title IV,
Section 428
2005Energy Policy Act of 2005 (amended §211 re
fuels)P.L. 109-58
2007Energy Independence and Security Act of 2007
(amended §211 re fuels)P.L. 110-140
Like many other programs administered by the Environmental Protection
Agency, federal efforts to control air pollution have gone through several phases,
beginning with information collection, research, and technical assistance, before
being strengthened to establish federal standards and enforcement. Federal
legislation addressing air pollution was first passed in 1955, prior to which air
pollution was the exclusive responsibility of state and local levels of government.
The federal role was strengthened in subsequent amendments, notably the Clean
Air Act Amendments of 1970, 1977, and 1990. The 1970 amendments established
the procedures under which EPA sets national standards for air quality, required a
90% reduction in emissions from new automobiles by 1975, established a program
to require the best available control technology at major new sources of air pollution,
established a program to regulate air toxics, and greatly strengthened federal
enforcement authority. The 1977 amendments adjusted the auto emission standards,
extended deadlines for the attainment of air quality standards, and added the
Prevention of Significant Deterioration program to protect air cleaner than national

Changes to the Act in 1990 included provisions to (1) classify most
nonattainment areas according to the extent to which they exceed the standard,
tailoring deadlines, planning, and controls to each area’s status; (2) tighten auto and
other mobile source emission standards; (3) require reformulated and alternative fuels
in the most polluted areas; (4) revise the air toxics section, establishing a new
program of technology-based standards and addressing the problem of sudden,
catastrophic releases of toxics; (5) establish an acid rain control program, with a
marketable allowance scheme to provide flexibility in implementation; (6) require
a state-run permit program for the operation of major sources of air pollutants; (7)
implement the Montreal Protocol to phase out most ozone-depleting chemicals; and
(8) update the enforcement provisions so that they parallel those in other pollution
control acts, including authority for EPA to assess administrative penalties.
The 1990 amendments also authorized appropriations for clean air programs
through FY1998. The Act has not been reauthorized since then. House rules require
enactment of an authorization before an appropriation bill can be considered; but this
requirement can be waived and frequently has been. Thus, while authorization of
appropriations in the Clean Air Act (and most other environmental statutes) have
expired, programs have continued and have been funded. The Act’s other legal
authorities, to issue and enforce regulations, are, for the most part, permanent and are
not affected by the lack of authorization.
The remainder of this report describes major programs required by the Act, with
an emphasis on the changes established by the 1990 amendments.
National Ambient Air Quality Standards
In section 109, the Act requires EPA to establish National Ambient Air Quality
Standards (NAAQS) for air pollutants that endanger public health or welfare, in the
Administrator’s judgment, and whose presence in ambient air results from numerous
or diverse sources. The NAAQS must be designed to protect public health and
welfare with an adequate margin of safety. Using this authority, EPA has
promulgated NAAQS for six air pollutants: sulfur dioxide (SO2), particulate matter
(PM2.5 and PM10), nitrogen dioxide (NO2), carbon monoxide (CO), ozone,1 and lead.
The Act requires EPA to review the scientific data upon which the standards are
based, and revise the standards, if necessary, every five years. More often than not,
however, EPA has taken more than five years in reviewing and revising the
Originally, the Act required that the NAAQS be attained by 1977 at the latest,
but the states experienced widespread difficulty in complying with these deadlines.
As a result, the deadlines have been extended several times. Under the 1990
amendments, most areas not in attainment with NAAQS must meet special
compliance schedules, staggered according to the severity of an area’s air pollution

1 Unlike the other NAAQS pollutants, ozone is not directly emitted, but rather is formed in
the atmosphere by the interaction of volatile organic compounds (VOCs) and nitrogen
oxides (NOx) in the presence of sunlight. The control of ozone is, thus, based on regulating
emissions of VOCs and NOx.

problem. The amendments also established specific requirements for each
nonattainment category, as described below.
State Implementation Plans
While the Act authorizes the EPA to set NAAQS, the states are responsible for
establishing procedures to attain and maintain the standards. Under Section 110 of
the Act, the states adopt plans, known as State Implementation Plans (SIPs), and
submit them to EPA to ensure that they are adequate to meet statutory requirements.
SIPs are based on emission inventories and computer models to determine
whether air quality violations will occur. If these data show that standards would be
exceeded, the state imposes additional controls on existing sources to ensure that
emissions do not cause “exceedances” of the standards. Proposed new and modified
sources must obtain state construction permits in which the applicant shows how the
anticipated emissions will not exceed allowable limits. In nonattainment areas,
emissions from new or modified sources must also be offset by reductions in
emissions from existing sources.
The 1990 amendments require EPA to impose sanctions in areas which fail to
submit a SIP, fail to submit an adequate SIP, or fail to implement a SIP: unless the
state corrects such failures, a 2-to-1 emissions offset for the construction of new
polluting sources is imposed 18 months after notification to the state, and a ban on
most new federal highway grants is imposed six months later. An additional ban on
air quality grants is discretionary. Ultimately, a Federal Implementation Plan may
be imposed if the state fails to submit or implement an adequate SIP.
The amendments also require that, in nonattainment areas, no federal permits
or financial assistance may be granted for activities that do not “conform” to a State
Implementation Plan. This requirement can cause a temporary suspension in funding
for most new highway and transit projects if an area fails to demonstrate that the
emissions caused by such projects are consistent with attainment and maintenance
of ambient air quality standards. Demonstrating conformity of transportation plans
and SIPs is required in nonattainment areas whenever new plans are submitted.
Nonattainment Requirements
In a major departure from the prior law, the 1990 Clean Air Act Amendments
grouped most nonattainment areas into classifications based on the extent to which
the NAAQS was exceeded, and established specific pollution controls and attainment
dates for each classification. These requirements are described here as spelled out2
in Sections 181-193 of the Act.

2 EPA modified the ozone standard, specified in the statute as 0.12 parts per million (ppm)
averaged over a 1-hour period, to 0.08 ppm averaged over an 8-hour period, through
regulations promulgated in July 1997. In April 2004, the agency promulgated an
implementation rule for the new 8-hour standard. Under this rule, the 1-hour standard was
revoked as of June 15, 2005, and areas that had not yet attained it were converted to new

Nonattainment areas are classified on the basis of a “design value,” which is
derived from the pollutant concentration (in parts per million or micrograms per
cubic meter) recorded by air quality monitoring devices. The design value for the 1-
hour ozone standard was the fourth highest hourly reading measured during the most
recent three-year period. Using these design values, the Act created five classes of
ozone nonattainment, as shown in Table 2. Only Los Angeles fell into the “extreme”
class, but 97 other areas were classified in one of the other four ozone categories. A
simpler classification system established moderate and serious nonattainment areas
for carbon monoxide and particulate matter with correspondingly more stringent
control requirements for the more polluted class.
Table 2. Ozone Nonattainment Classifications
Class M arginal M oderate Serious Severe Extreme
Deadline199319961999 2005-2007*2010
Areas**42 areas32 areas14 areas9 areas1 area
Design0.121 ppm-0.138 ppm-0.160 ppm-0.180 ppm->0.280 ppm
Value0.138 ppm0.160 ppm0.180 ppm0.280 ppm
*Areas with a 1988 design value between 0.190 and 0.280 ppm have 17 years to attain; others have
15 years.
** Number of areas in each category as of the date of enactment.
As shown in the table, the deadlines for attainment for ozone nonattainment
areas stretched from 1993 to 2010, depending on the severity of the problem. (Under
the 8-hour ozone standard, which replaced the 1-hour standard in 2004, these
deadlines are changed to 2007 to 2021.) For carbon monoxide, the attainment date
for moderate areas was December 31, 1995, and for serious areas, December 31,
2000. For particulate matter, the deadline for areas designated moderate
nonattainment as of 1990 was December 31, 1994; for those areas subsequently
designated as moderate, the deadline is six years after designation. For serious areas,
the respective deadlines are December 31, 2001 or 10 years after designation.
Requirements for Ozone Nonattainment Areas. Although areas with
more severe air pollution problems have a longer time to meet the standards, more
stringent control requirements are imposed in areas with worse pollution. A

2 (...continued)
classifications depending on their 8-hour concentration of ozone. As a result of court
challenges, the ramifications of this conversion to the 8-hour standard are still unfolding,
but in general the former 1-hour nonattainment areas remain subject to the controls specified
for their 1-hour category. New nonattainment areas that did not exceed the 1-hour standard,
but do violate the 8-hour standard, in general are subject to more flexible controls under
Subpart 1 (Sections 171-179B) of the act. The standard was revised again in March 2008,
to 0.075 ppm averaged over 8 hours. Nonattainment areas for the 2008 revision are
expected to be designated in 2010.

summary of the primary ozone control requirements for each nonattainment category
Marginal Areas
!Inventory emissions sources (to be updated every three years).
!Require 1.1 to 1 offsets (i.e., new major emission sources of volatile
organic compounds [VOCs] must reduce VOC emissions from
existing facilities in the area by 10% more than the emissions of the
new facility).
!Impose reasonably available control technology (RACT) on all
major sources emitting more than 100 tons per year for the nine
industrial categories where EPA had already issued control
technique guidelines describing RACT prior to 1990.
Moderate Areas
!Meet all requirements for marginal areas.
!Impose a 15% reduction in VOC emissions in six years.
!Adopt a basic vehicle inspection and maintenance program.
!Impose RACT on all major sources emitting more than 100 tons per
year for all additional industrial categories where EPA will issue
control technique guidelines describing RACT.
!Require vapor recovery at gas stations selling more than 10,000
gallons per month.
!Require 1.15 to 1 offsets.
Serious Areas
!Meet all requirements for moderate areas.
!Reduce definition of a major source of VOCs from emissions of 100
tons per year to 50 tons per year for the purpose of imposing RACT.
!Reduce VOCs 3% annually for years 7 to 9 after the 15% reduction
already required by year 6.
!Improve monitoring.
!Adopt an enhanced vehicle inspection and maintenance program.
!Require fleet vehicles to use clean alternative fuels.

!Adopt transportation control measures if the number of vehicle miles
traveled in the area is greater than expected.
!Require 1.2 to 1 offsets.
!Adopt contingency measures if the area does not meet required VOC
Severe Areas
!Meet all requirements for serious areas.
!Reduce definition of a major source of VOCs from emissions of 50
tons per year to 25 tons per year for the purpose of imposing RACT.
!Adopt specified transportation control measures.
!Implement a reformulated gasoline program.
!Require 1.3 to 1 offsets.
!Impose $5,000 per ton penalties on major sources if the area does
not meet required reductions.
Extreme Areas
!Meet all requirements for severe areas.
!Reduce definition of a major source of VOCs from emissions of 25
tons per year to 10 tons per year for the purpose of imposing RACT.
!Require clean fuels or advanced control technology for boilers
emitting more than 25 tons per year of NOx.
!Require 1.5 to 1 offsets.
As noted, EPA promulgated a new, 8-hour ozone standard in July 1997.
Following extensive court challenges, the agency designated nonattainment areas for
the new standard on April 30, 2004. State Implementation Plans were required to be
submitted in 2007.
Requirements for Carbon Monoxide Nonattainment Areas. As with
ozone nonattainment areas, carbon monoxide (CO) nonattainment areas are subjected
to specified control requirements, with more stringent requirements in Serious
nonattainment areas. A summary of the primary CO control requirements for each
nonattainment category follows.
Moderate Areas
!Conduct an inventory of emissions sources.

!Forecast total vehicle miles traveled in the area.
!Adopt an enhanced vehicle inspection and maintenance program.
!Demonstrate annual improvements sufficient to attain the standard.
Serious Areas
!Adopt specified transportation control measures.
!Implement an oxygenated fuels program for all vehicles in the area.
!Reduce definition of a major source of CO from emissions of 100
tons per year to 50 tons per year if stationary sources contribute
significantly to the CO problem.
Serious areas failing to attain the standard by the deadline have to revise their
SIP and demonstrate reductions of 5% per year until the standard is attained.
Requirements for Particulate Nonattainment Areas. Particulate (PM10)
nonattainment areas are also subject to specified control requirements. These are:
Moderate Areas
!Require permits for new and modified major stationary sources of
!Impose reasonably available control measures (RACM).
Serious Areas
!Impose best available control measures (BACM).
!Reduce definition of a major source of PM10 from 100 tons per year
to 70 tons per year.
In July 1997, EPA promulgated new standards for fine particulates (PM2.5). The
PM2.5 standards were also subject to court challenges. The absence of a monitoring
network capable of measuring the pollutant delayed implementation as well.
Nonattainment areas for PM2.5 were designated on April 14, 2005. States had three
years subsequent to designation to submit State Implementation Plans. Revisions to
the NAAQS promulgated in October 2006 strengthened the PM2.5 standard.
Emission Standards for Mobile Sources
Title II of the Clean Air Act has required emission standards for automobiles
since 1968. The 1990 amendments significantly tightened these standards: for cars,
the hydrocarbon standard was reduced by 40% and the nitrogen oxides (NOx)

standard by 50%. The standards — referred to as “Tier 1” standards — were phased
in over the 1994-1996 model years.
The amendments envisioned a further set of reductions (“Tier 2” standards), but
not before model year 2004. For Tier 2 standards to be promulgated, the agency was
first required to report to Congress concerning the need for further emission
reductions, the availability of technology to achieve such reductions, and the cost-
effectiveness of such controls compared to other means of attaining air quality
standards. EPA submitted this report to Congress in August 1998, concluding that
further emission reductions were needed and that technology to achieve such
reductions was available and cost-effective. Tier 2 standards, requiring emission
reductions of 77% to 95% from cars and light trucks were promulgated in February
2000, and were phased in over the 2004-2009 model years. To facilitate the use of
more effective emission controls, the standards also require a more than 90%
reduction in the sulfur content of gasoline, beginning in 2004.
The 1990 amendments also required that oxygenated gasoline, designed to
reduce emissions of carbon monoxide, be sold in the worst CO nonattainment areas
and that “reformulated” gasoline (RFG), designed to reduce emissions of volatile
organic compounds and toxic air pollutants, be sold in the nine worst ozone
nonattainment areas (Los Angeles, San Diego, Houston, Baltimore, Philadelphia,
New York, Hartford, Chicago, and Milwaukee); metropolitan Washington, D.C., and
four areas in California were added to the mandatory list later. Other ozone
nonattainment areas can opt in to the RFG program; as of 2006, additional areas in

11 states had done so.

The fuels provisions were modified by the Energy Policy Act of 2005 (EPACT),
removing the requirement that RFG contain oxygenates. Instead, EPACT required
the use of increasing amounts of renewable fuel, most likely to be ethanol, in motor
fuels, beginning in 2006. The Energy Independence and Security Act of 2007 further
strengthened the renewable fuel requirements.
Use of alternative fuels and development of cleaner engines was also to be
stimulated by the Clean-Fuel Fleet Program. In all of the most seriously polluted
ozone and CO nonattainment areas, centrally fueled fleets of 10 or more passenger
cars and light-duty trucks must purchase at least 30% clean-fuel vehicles when they
add new vehicles to existing fleets, starting in 1999. (The Act originally required the
program to begin in 1998, but the start was delayed by a year.) The percentage rose
to 50% in 2000 and 70% in 2001. Heavy-duty fleets are required to purchase at least
50% clean-fuel vehicles annually. A clean fuel vehicle is one which meets Low
Emission Vehicle (LEV) standards and operates on reformulated gasoline,
reformulated diesel, methanol, ethanol, natural gas, liquefied petroleum gas,
hydrogen, or electricity.
In addition to the above program, California’s Zero Emission Vehicle (ZEV)
program also is intended to promote the development of alternative fuels and
vehicles. Section 209(b) of the Clean Air Act grants California the authority to
develop its own vehicle emissions standards if those standards are at least as stringent
as the federal standards. In addition to setting more stringent standards for all
vehicles, California used this authority to establish a program requiring auto

manufacturers to sell ZEVs (electric or hydrogen fuel cell vehicles) in the state
beginning in 2003. This program has been substantially modified since it was
enacted, and now allows credit for hybrid and partial ZEV vehicles in addition to true
ZEVs, but it has served as an incubator for lower emission technologies since its
adoption. Section 177 of the Act allows other states to adopt California’s stricter
standards: at least ten states (Connecticut, Maine, Massachusetts, New Jersey, New
York, Oregon, Pennsylvania, Rhode Island, Vermont, and Washington) have already
adopted them or are in the process of doing so.
The 1990 amendments also imposed tighter requirements on certification (an
auto’s useful life is defined as 100,000 miles instead of the earlier 50,000 miles), on
emissions allowed during refueling, on low temperature CO emissions, on in-use
performance over time, and on warranties for the most expensive emission control
components (8 years/80,000 miles for the catalytic converter, electronic emissions
control unit, and onboard emissions diagnostic unit). Regulations were also extended
to include nonroad fuels and engines.
Standards for trucks and buses using diesel engines were also strengthened. The
1990 amendments required new urban buses to reduce emissions of diesel
particulates 92% by 1996, and all other heavy-duty diesel engines to achieve an 83%
reduction by the same year. NOx emissions must also be reduced, 33% by 1998.
Authority to further strengthen these standards led to promulgation in January 2001
of new emission standards requiring a further 90%-95% reduction in emissions
phased in over the 2007-2010 model years, and a reduction of 97% in the allowable
amount of sulfur in highway diesel fuel. These regulations were followed in May
2004 by similar requirements for nonroad diesel equipment, which will be phased in
between 2007 and 2015.
Hazardous Air Pollutants3
Completely rewritten by the Clean Air Act Amendments of 1990, Section 112
of the Act establishes programs for protecting public health and the environment
from exposure to toxic air pollutants. As revised by the 1990 amendments, the
section contains four major provisions: Maximum Achievable Control Technology
(MACT) requirements; health-based standards; standards for stationary “area
sources” (small, but numerous sources, such as gas stations or dry cleaners, that
collectively emit significant quantities of hazardous pollutants); and requirements
for the prevention of catastrophic releases.
First, EPA is to establish technology-based emission standards, called MACT
standards, for sources of 188 pollutants listed in the legislation, and to specify
categories of sources subject to the emission standards.4 EPA is to revise the

3 This section of the report was written by Linda-Jo Schierow, Specialist in Environmental
4 The 1990 amendments specified 189 pollutants, but Public Law 102-187, enacted on
December 4, 1991, deleted hydrogen sulfide from the list of toxic pollutants, leaving only


standards periodically (at least every eight years). EPA can, on its initiative or in
response to a petition, add or delete substances or source categories from the lists.
Section 112 establishes a presumption in favor of regulation for the designated
chemicals; it requires regulation of a designated pollutant unless EPA or a petitioner
is able to show “that there is adequate data on the health and environmental effects
of the substance to determine that emissions, ambient concentrations,
bioaccumulation or deposition of the substance may not reasonably be anticipated to
cause any adverse effects to human health or adverse environmental effects.”
EPA is required to set standards for sources of the listed pollutants that achieve
“the maximum degree of reduction in emissions” taking into account cost and other
non-air-quality factors. These MACT standards for new sources “shall not be less
stringent than the most stringent emissions level that is achieved in practice by the
best controlled similar source.” The standards for existing sources may be less
stringent than those for new sources, but must be no less stringent than the emission
limitations achieved by either the best performing 12% of existing sources (if there
are more than 30 such sources in the category or subcategory) or the best performing
5 similar sources (if there are fewer than 30). Existing sources are given three years
following promulgation of standards to achieve compliance, with a possible one-year
extension; additional extensions may be available for special circumstances or for
certain categories of sources. Existing sources that achieve voluntary early emissions
reductions will receive a six-year extension for compliance with MACT.
The second major provision of Section 112 directs EPA to set health-based
standards to address situations in which a significant residual risk of adverse health
effects or a threat of adverse environmental effects remains after installation of
MACT. This provision requires that EPA, after consultation with the Surgeon
General of the United States, submit a report to Congress on the public health
significance of residual risks, and recommend legislation regarding such risks. If
Congress does not legislate in response to EPA’s recommendations, then EPA is
required to issue standards for categories of sources of hazardous air pollutants as
necessary to protect the public health with an ample margin of safety or to prevent
an adverse environmental effect. A residual risk standard is required for any source
emitting a cancer-causing pollutant that poses an added risk to the most exposed
person of more than one-in-a-million. Residual risk standards are due eight years
after promulgation of MACT for the affected source category. Existing sources have

90 days to comply with a residual risk standard, with a possible two-year extension.

In general, residual risk standards do not apply to area sources.
The law directed EPA to contract with the National Academy of Sciences
(NAS) for a study of risk assessment methodology, and created a Risk Assessment
and Management Commission to investigate and report on policy implications and
appropriate uses of risk assessment and risk management. In 1994 NAS published
its report, Science and Judgment in Risk Assessment. The Commission study,
Framework for Environmental Health Risk Management, was released in 1997.
Third, in addition to the technology-based and health-based programs for major
sources of hazardous air pollution, EPA is to establish standards for stationary “area
sources” determined to present a threat of adverse effects to human health or the

environment. The provision requires EPA to regulate the stationary area sources
responsible for 90% of the emissions of the 30 hazardous air pollutants that present
the greatest risk to public health in the largest number of urban areas. In setting the
standard, EPA can impose less stringent “generally available” control technologies,
rather than MACT.
Finally, Section 112 addresses prevention of sudden, catastrophic releases of air
toxics by establishing an independent Chemical Safety and Hazard Investigation
Board. The Board is responsible for investigating accidents involving releases of
hazardous substances, conducting studies, and preparing reports on the handling of
toxic materials and measures to reduce the risk of accidents.
EPA is also directed to issue prevention, detection, and correction requirements
for catastrophic releases of air toxics by major sources. Section 112(r) requires
owners and operators to prepare risk management plans including hazard
assessments, measures to prevent releases, and a response program.
New Source Performance Standards5
Section 111 of the Act requires EPA to establish nationally uniform,
technology-based standards (called New Source Performance Standards, or NSPS)
for categories of new industrial facilities. These standards accomplish two goals:
first, they establish a consistent baseline for pollution control that competing firms
must meet, and thereby remove any incentive for states or communities to weaken
air pollution standards in order to attract polluting industry; and second, they preserve
clean air to accommodate future growth, as well as for its own benefits.
NSPS establish maximum emission levels for new major stationary sources —
powerplants, steel mills, and smelters, for example — with the emission levels
determined by the best “adequately demonstrated” continuous control technology
available, taking costs into account. EPA must regularly revise and update NSPS
applicable to designated sources as new technology becomes available, since the goal
is to prevent new pollution problems from developing and to force the installation of
new control technology.
The standards also apply to modifications of existing facilities, through a
process called New Source Review (NSR). The law’s ambiguity regarding what
constitutes a modification (subject to NSR) as opposed to routine maintenance of a
facility has led to litigation, with EPA proposing in recent years to modify its
interpretation of the requirements of this section.
Solid Waste Incinerators
Prior to 1990, solid waste incinerators, which emit a wide range of pollutants,
were subject to varying degrees of state and federal regulation depending on their
size, age, and the type of waste burned. In a new Section 129, the 1990 amendments

5 This section of the report was written by Larry B. Parker, Specialist in Energy and
Environmental Policy.

established more consistent federal requirements specifying that emissions of 10
categories of pollutants be regulated at new and existing incinerators burning
municipal solid waste, medical waste, and commercial and industrial waste. The
amendments also established emissions monitoring and operator training
Prevention of Significant Deterioration / Regional Haze6
Sections 160-169 of the act establish requirements for the prevention of
significant deterioration of air quality (PSD). The PSD program reflects the principle
that areas where air quality is better than that required by NAAQS should be
protected from significant new air pollution even if NAAQS would not be violated.
The Act divides clean air areas into three classes, and specifies the increments
of SO2 and particulate pollution allowed in each. Class I areas include international
and national parks, wilderness and other pristine areas; allowable increments of new
pollution are very small. Class II areas include all attainment and not classifiable
areas, not designated as Class I; allowable increments of new pollution are modest.
Class III represents selected areas that states may designate for development;
allowable increments of new pollution are large (but not exceeding NAAQS).
Through an elaborate hearing and review process, a state can have regions
redesignated from Class II to Class III (although none have yet been so redesignated).
While the 1977 amendments only stipulated PSD standards for two pollutants,
SO2 and particulates, EPA is supposed to establish standards for other criteria
pollutants. Thus far, only one of the other four (NO2) has been addressed: the agency
promulgated standards for NO2 in 1988.
Newly constructed polluting sources in PSD areas must install best available
control technology (BACT) that may be more strict than that required by NSPS. The
justifications of the policy are that it protects air quality, provides an added margin
of health protection, preserves clean air for future development, and prevents firms
from gaining a competitive edge by “shopping” for clean air to pollute.
In Sections 169A and B, the Act also sets a national goal of preventing and
remedying impairment of visibility in national parks and wilderness areas, and
requires EPA to promulgate regulations to assure reasonable progress toward that
goal. In the 1990 Amendments, Congress strengthened these provisions, which had
not been implemented.
The amendments required EPA to establish a Grand Canyon Visibility Transport
Commission, composed of Governors from each state in the affected region, an EPA
designee, and a representative of each of the national parks or wilderness areas in the
region. Other visibility transport commissions can be established upon EPA’s
discretion or upon petition from at least two states. Within 18 months of receiving
a report from one of these commissions, EPA is required to promulgate regulations

6 This section of the report was written by Larry B. Parker, Specialist in Energy and
Environmental Policy and James E. McCarthy, Specialist in Environmental Policy.

to assure reasonable progress toward the visibility goal, including requirements that
states update their State Implementation Plans to contain emission limits, schedules
of compliance, and other measures necessary to make reasonable progress.
Specifically mentioned is a requirement that states impose Best Available Retrofit
Technology on existing sources of emissions impairing visibility.
The Grand Canyon Commission delivered a set of recommendations to EPA in
June 1996, and the agency subsequently promulgated a “regional haze” program
applicable to all 50 states under this authority.
Acid Deposition Control7
The Clean Air Act Amendments of 1990 added an acid deposition control
program (Title IV) to the Act. It sets goals for the year 2000 of reducing annual SO2
emissions by 10 million tons from 1980 levels and reducing annual NOx emissions
by 2 million tons, also from 1980 levels.
The SO2 reductions are imposed in two steps. Under Phase 1, owners/operators
of 111 electric generating facilities listed in the law that are larger than 100
megawatts had to meet tonnage emission limitations by January 1, 1995. This would
reduce SO2 emission by about 3.5 million tons. Phase 2 included facilities larger
than 75 megawatts, with a deadline of January 1, 2000. So far, compliance has been


To introduce some flexibility in the distribution and timing of reductions, the
Act creates a comprehensive permit and emissions allowance system. An allowance
is a limited authorization to emit a ton of SO2. Issued by EPA, the allowances would
be allocated to Phase 1 and Phase 2 units in accordance with baseline emissions
estimates. Powerplants which commence operation after November 15, 1990 would
not receive any allowances. These new units would have to obtain allowances
(offsets) from holders of existing allowances. Allowances may be traded nationally
during either phase. The law also permits industrial sources and powerplants to sell
allowances to utility systems under regulations to be developed by EPA. Allowances
may be banked by a utility for future use or sale.
The Act provided for two types of sales to improve the liquidity of the
allowance system and to ensure the availability of allowances for utilities and
independent power producers who need them. First, a special reserve fund consisting
of 2.8% of Phase 1 and Phase 2 allowance allocations has been set aside for sale.
Allowances from this fund (25,000 annually from 1993-1999 and 50,000 thereafter)
are sold at a fixed price of $1,500 an allowance. Independent power producers have
guaranteed rights to these allowances under certain conditions. Second, an annual,
open auction sold allowances (150,000 from 1993-1995, and 250,000 from 1996-
1999) with no minimum price. Utilities with excess allowances may have them
auctioned off at this auction, and any person may buy allowances.

7 This section of the report was written by Larry B. Parker, Specialist in Energy and
Environmental Policy.

The Act essentially caps SO2 emissions at individual existing sources through
a tonnage limitation, and at future plants through the allowance system. First,
emissions from most existing sources are capped at a specified emission rate times
an historic baseline level. Second, for plants commencing operation after November
15, 1990, emissions must be completely offset with additional reductions at existing
facilities beginning after Phase 2 compliance. However, as noted above, the law
provides some allowances to future powerplants which meet certain criteria. The
utility SO2 emission cap is set at 8.9 million tons, with some exceptions.
The Act provides that if an affected unit does not have sufficient allowances to
cover its emissions, it is subject to an excess emission penalty of $2,000 per ton of
SO2 and required to reduce an additional ton of SO2 the next year for each ton of
excess pollutant emitted.
The Act also requires EPA to inventory industrial emissions of SO2 and to report
every five years, beginning in 1995. If the inventory shows that industrial emissions
may reach levels above 5.60 million tons per year, then EPA is to take action under
the Act to ensure that the 5.60 million ton cap is not exceeded.
The Act requires EPA to set specific NOx emission rate limitations — 0.45 lb.
per million Btu for tangentially-fired boilers and 0.50 lb. per million Btu for wall-
fired boilers — unless those rates can not be achieved by low-NOx burner technology.
Tangentially and wall-fired boilers affected by Phase 1 SO2 controls must also meet
NOx requirements. EPA was to set emission limitations for other types of boilers by
1997 based on low-NOx burner costs, which EPA did. In addition, EPA was to
propose and promulgate a revised new source performance standard for NOx from
fossil fuel steam generating units, which EPA also did, in 1998.
The Clean Air Act Amendments of 1990 added a Title V to the Act which
requires states to administer a comprehensive permit program for the operation of
sources emitting air pollutants. These requirements are modeled after similar
provisions in the Clean Water Act. Previously, the Clean Air Act contained limited
provision for permits, requiring only new or modified major stationary sources to
obtain construction permits (under Section 165 of the Act).
Sources subject to the permit requirements generally include major sources that
emit or have the potential to emit 100 tons per year of any regulated pollutant, plus
stationary and area sources that emit or have potential to emit lesser specified
amounts of hazardous air pollutants. However, in nonattainment areas, the permit
requirements also include sources which emit as little as 50, 25, or 10 tons per year
of VOCs, depending on the severity of the region’s nonattainment status (serious,
severe, or extreme).

8 This section of the report was written by Claudia Copeland, Specialist in Environmental

States were required to develop permit programs and to submit those programs
for EPA approval by November 15, 1993. EPA had one year to approve or
disapprove a state’s submission in whole or in part. After the effective date of a state
plan, sources had 12 months to submit an actual permit application.
States are to collect annual fees from sources sufficient to cover the “reasonable
costs” of administering the permit program, with revenues to be used to support the
agency’s air pollution control program. The fee must be at least $25 per ton of
regulated pollutants (excluding carbon monoxide). Permitting authorities have
discretion not to collect fees on emissions in excess of 4,000 tons per year and may
collect other fee amounts, if appropriate.
The permit states how much of which air pollutants a source is allowed to emit.
As a part of the permit process, a source must prepare a compliance plan and certify
compliance. The term of permits is limited to no more than five years; sources are
required to renew permits at that time. State permit authorities must notify
contiguous states of permit applications that may affect them; the application and any
comments of contiguous states must be forwarded to EPA for review. EPA can veto
a permit; however, this authority is essentially limited to major permit changes. EPA
review need not include permits which simply codify elements of a state’s overall
clean air plan, and EPA has discretion to not review permits for small sources.
Holding a permit to some extent shields a source from enforcement actions: the Act
provides that a source cannot be held in violation if it is complying with explicit
requirements addressed in a permit, or if the state finds that certain provisions do not
apply to that source.
Section 113 of the Act, which was also strengthened by the 1990 amendments,
covers enforcement. The section establishes federal authority to issue agency and
court orders requiring compliance and to impose penalties for violations of Act
requirements. Section 114 authorizes EPA to require sources to submit reports,
monitor emissions, and certify compliance with the Act’s requirements, and
authorizes EPA personnel to conduct inspections.
Like most federal environmental statutes, the Clean Air Act is enforced
primarily by states or local governments; they issue most permits, monitor
compliance, and conduct the majority of inspections. The federal government
functions as a backstop, with authority to review state actions. The agency may act
independently or may file its own enforcement action in cases where it concludes
that a state’s response was inadequate.
The Act also provides for citizen suits both against persons (including
corporations or government agencies) alleged to have violated emissions standards
or permit requirements, and against EPA in cases where the Administrator has failed
to perform an action that is not discretionary under the Act. Citizen groups have
often used the latter provision to compel the Administrator to promulgate regulations
required by the statute.

The 1990 Amendments elevated penalties for some knowing violations from
misdemeanors to felonies; removed the ability of a source to avoid an enforcement
order or civil penalty by ceasing a violation within 60 days of notice; gave authority
to EPA to assess administrative penalties; and authorized $10,000 awards to persons
supplying information leading to convictions under the Act.
Stratospheric Ozone Protection9
Title VI of the 1990 Clean Air Act Amendments represents the United States’
primary response on the domestic front to the ozone depletion issue. It also
implements the U.S. international responsibilities under the Montreal Protocol on
Substances that Deplete the Ozone Layer (and its amendments). Indeed, Section
606(a)(3) provides that the Environmental Protection Agency shall adjust phase-out
schedules for ozone-depleting substances in accordance with any future changes in
Montreal Protocol schedules. As a result, the phase-out schedules contained in Title
VI for various ozone-depleting compounds have now been superseded by subsequent
amendments to the Montreal Protocol.
Since passage of Title VI, depleting substances such as CFCs, methyl
chloroform, carbon tetrachloride, and halons (referred to as Class 1 substances) have
been phased out by industrial countries, including the United States. New uses of
hydrochlorofluorocarbons (HCFCs) (called Class 2 substances under Title VI) are
banned beginning January 1, 2015, unless the HCFCs are recycled, used as a
feedstock, or used as a refrigerant for appliances manufactured prior to January 1,
2020. Production of HCFCs is to be frozen January 1, 2015 and phased out by
January 1, 2030. Exemptions consistent with the Montreal Protocol are allowed.
The EPA is required to add any substance with an ozone depletion potential
(ODP) of 0.2 or greater to the list of Class 1 substances and set a phase-out schedule
of no more than seven years. For example, methyl bromide (ODP estimated by EPA
at 0.7) was added to the list in December 1993, requiring its phaseout by January 1,
2001; this decision was altered by Congress in 1998 to harmonize the U.S. methyl
bromide phase-out schedule with the 2005 deadline set by the parties to the Montreal
Protocol in 1997. Also, EPA is required to add any substance that is known or may
be reasonably anticipated to harm the stratosphere to the list of Class 2 substances
and set a phase-out schedule of no more than ten years.
Title VI contains several implementing strategies to avoid releases of ozone-
depleting chemicals to the atmosphere, including (1) for Class 1 substances used as
refrigerant — lowest achievable level of use and emissions, maximum recycling, and
safe disposal required by July 1, 1992; (2) for servicing or disposing refrigeration
equipment containing Class 1 and 2 substances — venting banned as of July 1, 1992;
(3) for motor vehicle air conditioners containing Class 1 or 2 substances — recycling
required by January 1, 1992 (smaller shops by January 1, 1993); (4) sale of small
containers of class 1 and 2 substances — banned within two years of enactment; and
(5) nonessential products — banned within two years of enactment.

9 This section of the report was written by Larry B. Parker, Specialist in Energy and
Environmental Policy.

Selected References
U.S. Environmental Protection Agency. Office of Air Quality Planning and
Standards. Air Trends. Research Triangle Park, NC. Compiled annually, and
available at [].
Martineau, Robert J., Jr. and Novello, David P. (eds.). The Clean Air Act Handbook.

2nd edition. Chicago: American Bar Association, 2004. 728 p.

For recent issues, see CRS Report RL33776, Clean Air Act Issues in the 110th
Congress: Implementation and Oversight. A similar report discussing clean air
issues in the 111th Congress is forthcoming.
Table 3. Major U.S. Code Sections of the Clean Air Act10
(codified generally as 42 U.S.C. 7401-7671)
Clean Air Act,
42 U.S.C.Section Titleas amended
Subchapter I -Programs and Activities
Part A -Air Quality Emissions and Limitations
7401Findings, purposeSec. 101
7402Cooperative activitiesSec. 102
7403Research, investigation, trainingSec. 103
7404Research relating to fuels and vehiclesSec. 104
7405Grants for air pollution planning and controlSec. 105
7406Interstate air quality agencies; program costSec. 106
7407Air quality control regionsSec. 107
7408Air quality criteria and control techniquesSec. 108
7409National primary and secondary air qualitySec. 109
7410SIPs for national primary and secondary airSec. 110
quality standards
7411Standards of performance for new stationarySec. 111
7412Hazardous air pollutantsSec. 112

7413Federal enforcementSec. 113

10 NOTE: This tables shows only the major U.S. Code sections. For more detail and to
determine when a section was added, the reader should consult the official printed version
of the U.S. Code.

Clean Air Act,
42 U.S.C.Section Titleas amended
7414Recordkeeping, inspections, monitoring, andSec. 114
7415International air pollutionSec. 115
7416Retention of state authoritySec. 116
7417Advisory committeesSec. 117
7418Control of pollution from federal facilitiesSec. 118
7419Primary nonferrous smelter ordersSec. 119
7420Noncompliance penaltySec. 120
7421ConsultationSec. 121
7422Listing of certain unregulated pollutantsSec. 122
7423Stack heightsSec. 123
7424Assurance of adequacy of state plansSec. 124
7425Measures to prevent economicSec. 125
7426Interstate pollution abatementSec. 126
7427Public notificationSec. 127
7428State boardsSec. 128
7429Solid waste combustionSec. 129
7430Emission factorsSec. 130
7431Land use authoritySec. 131
Part B - Ozone Protection (repealed — new provisions related to stratospheric ozone
protection are found at 42 U.S.C. 7671 et seq., below)
Part C -Prevention of Significant Deterioration of Air Quality
Subpart I - Clean Air
7470Congressional declaration of purposeSec. 160
7471Plan requirementsSec. 161
7472Initial classificationsSec. 162
7473Increments and ceilingsSec. 163
7474Area redesignationSec. 164
7475Preconstruction requirementsSec. 165
7476Other pollutantsSec. 166
7477EnforcementSec. 167

7478Period before plan approvalSec. 168

Clean Air Act,
42 U.S.C.Section Titleas amended
7479Definitions Sec. 169
Subpart II -Visibility Protection
7491Visibility protection for federal class I areasSec. 169A
7492VisibilitySec. 169B
Part D -Plan Requirements for Nonattainment Areas
Subpart 1 - Nonattainment Areas in General
7501DefinitionsSec. 171
7502Nonattainment plan provisions in generalSec. 172
7503Permit requirementsSec. 173
7504Planning proceduresSec. 174
7505Environmental Protection Agency grantsSec. 175
7505aMaintenance plansSec. 175A
7506Limitations on certain federal assistanceSec. 176
7506aInterstate transport commissionsSec. 176A
7507New motor vehicle emission standards inSec. 177
nonattainment areas
7508Guidance documentsSec. 178
7509Sanctions and consequences of failure toSec. 179
7509aInternational border areasSec. 179B
Subpart 2 - Additional Provisions for Ozone Nonattainment Areas
7511Classifications and attainment datesSec. 181
7511aPlan submissions and requirementsSec. 182
7511bFederal ozone measuresSec. 183
7511cControl of interstate ozone air pollutionSec. 184
7511dEnforcement for Severe and Extreme ozoneSec. 185
nonattainment areas for failure to attain
7511eTransitional areasSec. 185A
7511fNOx and VOC studySec. 185B
Subpart 3 - Additional Provisions for Carbon Monoxide Nonattainment Areas

7512Classification and attainment datesSec. 186

Clean Air Act,
42 U.S.C.Section Titleas amended
7512aPlan submissions and requirementsSec. 187
Subpart 4 - Additional Provisions for Particulate Matter Nonattainment Areas
7513Classifications and attainment datesSec. 188
7513aPlan provisions and schedules for planSec. 189
7513bIssuance of RACM and BACM guidanceSec. 190
Subpart 5 - Additional Provisions for Areas Designated Nonattainment for
Sulfur Oxides, Nitrogen Dioxide, or Lead
7514Plan submission deadlinesSec. 191
7514aAttainment datesSec. 192
Subpart 6 - Savings Provisions
7515General savings clauseSec. 193
Subchapter II -Emission Standards for Moving Sources
Part A - Motor Vehicle Emission and Fuel Standards
7521Emission standards for new motor vehicles orSec. 202
7522Prohibited actsSec. 203
7523Actions to restrain violationsSec. 204
7524Civil penaltiesSec. 205
7525Motor vehicle and engines testing andSec. 206
7541Compliance by vehicles and engines in actualSec. 207
7542Information collectionSec. 208
7543State standardsSec. 209
7544State grantsSec. 210
7545Regulation of fuelsSec. 211
7547Nonroad engines and vehiclesSec. 213
7548Study of particulate emissions from motorSec. 214
7549High altitude performance adjustmentsSec. 215

7550DefinitionsSec. 216

Clean Air Act,
42 U.S.C.Section Titleas amended
7551Study and report on fuel consumption ofSec. 203
CAAA of 1977
7552Motor vehicle compliance program fees Sec. 217
7553Prohibition on production of engines requiringSec. 218
leaded gasoline
7554Urban bus standardsSec. 219
Part B - Aircraft Emissions Standards
7571Establishment of standardsSec. 231
7572Enforcement of standardsSec. 232
7573State standards and controlsSec. 233
7574DefinitionsSec. 234
Part C -Clean Fuel Vehicles
7581DefinitionsSec. 241
7582Requirements applicable to clean-fuelSec. 242
7583Standards for light-duty clean-fuel vehicles Sec. 243
7584Administration and enforcement as perSec. 244
California standards
7585Standards for heavy-duty clean-fuel vehiclesSec. 245
7586Centrally fueled fleetsSec. 246
7587Vehicle conversionsSec. 247
7588Federal agency fleetsSec. 248
7589California pilot test programSec. 249
7590General provisionsSec. 250
Subchapter III - General Provisions
7601AdministrationSec. 301
7602DefinitionsSec. 302
7603Emergency powersSec. 303
7604Citizen suitsSec. 304
7605Representation in litigationSec. 305
7606Federal procurementSec. 306

7607Administrative proceedings and judicialSec. 307


Clean Air Act,
42 U.S.C.Section Titleas amended
7608Mandatory licensingSec. 308
7609Policy reviewSec. 309
7610Other authoritySec. 310
7611Records and auditsSec. 311
7612Economic impact analysesSec. 312
7614Labor standardsSec. 314
7615SeparabilitySec. 315
7616Sewage treatment plantsSec. 316
7617Economic impact assessmentSec. 317
7619Air quality monitoringSec. 319
7620Standardized air quality modelingSec. 320
7621Employment effectsSec. 321
7622Employee protectionSec. 322
7624Cost of vapor recovery equipment Sec. 323
7625Vapor recovery for small business marketersSec. 324
of petroleum products
7625-1Exemptions for certain territoriesSec. 325
7625aStatutory constructionSec. 326
7626Authorization of appropriationsSec. 327
7627Air pollution from Outer Continental ShelfSec. 328
Subchapter IV-AAcid Deposition Control
7651Findings and purposesSec. 401
7651aDefinitionsSec. 402
7651bSulfur dioxide allowance program for existingSec. 403
and new units
7651cPhase I sulfur dioxide requirementsSec. 404
7651dPhase II sulfur dioxide requirementsSec. 405
7651eAllowances for states with emissions rates atSec. 406
or below 0.80 lbs./mmBtu
7651fNitrogen oxides emission reduction programSec. 407
7651gPermits and compliance plansSec. 408
7651hRepowered sourcesSec. 409
7651iElection for additional sourcesSec. 410

7651jExcess emissions penaltySec. 411

Clean Air Act,
42 U.S.C.Section Titleas amended
7651kMonitoring, reporting, and recordkeepingSec. 412
7651lGeneral compliance with other provisionsSec. 413
7651mEnforcementSec. 414
7651nClean coal technology regulatory incentivesSec. 415
7651oContingency guarantee, auctions, reserveSec. 416
Subchapter V - Permits
7661DefinitionsSec. 501
7661aPermit programsSec. 502
7661bPermit applicationsSec. 503
7661cPermit requirements and conditionsSec. 504
7661dNotification to administrator and contiguousSec. 505
7661eOther authoritiesSec. 506
7661fSmall business stationary source technical andSec. 507
environmental compliance assistance program
Subchapter VI - Stratospheric Ozone Protection
7671DefinitionsSec. 601
7671aListing of class I and class II substancesSec. 602
7671bMonitoring and reporting requirementsSec. 603
7671cPhase-out of production and consumption ofSec. 604
class I substances
7671dPhase-out of production and consumption ofSec. 605
class II substances
7671eAccelerated scheduleSec. 606
7671fExchange authoritySec. 607
7671gNational recycling and emission reductionSec. 608
7671hServicing of motor vehicle air conditionersSec. 609
7671iNonessential products containingSec. 610
7671jLabelingSec. 611
7671kSafe alternatives policySec. 612
7671lFederal procurementSec. 613

7671mRelationship to other lawsSec. 614

Clean Air Act,
42 U.S.C.Section Titleas amended
7671nAuthority of AdministratorSec. 615
7671oTransfers among parties to Montreal ProtocolSec. 616
7671pInternational cooperationSec. 617
7671qMiscellaneous provisionsSec. 618
[29 U.S.C. 655]Chemical Process Safety Management Sec. 304 of CAA
of 1990
[29 U.S.C. 1662e]Clean Air Employment Transition Assistance Sec.1101 of
CAA of 1990