a

GAO

United States Government Accountability Office

Report to Congressional Requesters

May 2005 CLEAN AIR ACT

EPA Has Completed 

Most of the Actions 

Required by the 1990 

Amendments, but 

Many Were Completed 

Late

GAO-05-613
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

www.gao.gov/cgi-bin/getrpt?GAO-05-613.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact John B. 

Stephenson at (202) 512-3841 or 

stephensonj@gao.gov. 

Highlights of GAO-05-613, a report to 

congressional requesters 

May 2005

CLEAN AIR ACT

EPA Has Completed Most of the Actions 

Required by the 1990 Amendments, but 

Many Were Completed Late 

As of April 2005, EPA had completed 404 of the 452 actions required to 

meet the objectives of Titles I, III, and IV of the Clean Air Act 

Amendments of 1990. Of the 338 requirements that had statutory 

deadlines prior to April 2005, EPA completed 256 late: many (162) 2 years 

or less after the required date, but others (94) more than 2 years after 

their deadlines. Consequently, improvements in air quality associated 

with some of these requirements may have been delayed. The numerous 

actions required to implement these titles varied in scope and 

complexity. For example, these actions included reviewing numerous 

state plans to comply with national health- and welfare-based air quality 

standards for six major pollutants, setting technology-based standards to 

reduce emissions from sources of hazardous air pollutants, and 

developing a new program to reduce acid rain. EPA officials cited several 

reasons for the missed deadlines, including the emphasis on 

stakeholders’ involvement during regulatory development, which added 

to the time needed to issue regulations; the need to set priorities among 

the tremendous number of new responsibilities EPA assumed as a result 

of the 1990 amendments, which meant that some actions had to be 

delayed; and competing demands caused by the workload associated 

with EPA’s response to lawsuits challenging some of its rules. 

Of the 48 requirements EPA had not met as of April 2005, 45 had 

associated deadlines, and 3 did not. The unmet requirements include 15 

Title I requirements to promulgate regulations to limit the emissions of 

volatile organic compounds from a number of consumer and commercial 

products, such as household cleaners and pesticides. According to EPA 

officials, these rules were not completed because EPA shifted its 

priorities toward issuing standards related to the emissions of hazardous 

air pollutants regulated under Title III. However, the unmet requirements 

also include actions under Title III to periodically assess whether EPA’s 

emissions standards for sources that emit significant amounts of 

hazardous air pollutants appropriately protect public health. These 

“residual risk” assessments are to be made within 8 years of the setting of

each of the emissions standards, and 19 of these assessments are now 

past the 8-year mark. EPA completed the first of these residual risk 

assessments in March 2005. Any improvements in air quality that would 

result from EPA meeting these requirements remain unrealized. 

In commenting on a draft of this report, EPA generally agreed with our 

findings and provided supplemental information, primarily on the 

benefits of the Clean Air Act Amendments of 1990 and the reasons for 

implementation delays (see app. V). 

While air quality in the United 

States has steadily improved over 

the last few decades, more than a 

hundred million Americans 

continue to live in communities 

where pollution causes the air to be 

unhealthy at times, according to 

the Environmental Protection 

Agency (EPA). The Clean Air Act, 

first passed in 1963, was last 

reauthorized and amended in 1990, 

when new programs were created 

and changes were made to the 

ways in which air pollution is 

controlled. The 1990 amendments 

included hundreds of requirements 

for EPA, as well as other parties, to 

take steps that will ultimately 

reduce air pollution. The 

amendments also established 

deadlines for many of these 

requirements. Since the 1990 

amendments, various actions have 

been proposed to either amend the 

Clean Air Act or implement its 

provisions in new ways. 

GAO was asked to report on the 

current status of EPA’s 

implementation of requirements 

under Titles I, III, and IV of the 

1990 amendments. These titles, 

which address national ambient air 

quality standards, hazardous air 

pollutants, and acid deposition 

control, respectively, are the most 

relevant to proposed legislation 

and recently finalized regulations 

addressing emissions of air 

pollutants by power plants. 
Page i GAO-05-613 Clean Air Act

Contents

Letter 1

Results in Brief 3

Background 4

EPA Has Implemented Almost All Required Actions, but Many Were 

Implemented Late 7

Observations 12

Agency Comments and Our Evaluation 13

Appendixes

Appendix I: Title I 14

Appendix II: Title III 20

Appendix III: Title IV 25

Appendix IV: Objective, Scope, and Methodology 28

Appendix V: Comments from the Environmental Protection Agency 30

Appendix VI: GAO Contacts and Staff Acknowledgments 38

Tables Table 1: Requirements with and without Statutory Deadlines as of 

April 2005, by Related Title 8

Table 2: Status of Title I-, III-, and IV-Related Requirements as of 

April 2005 9

Table 3: Length of Time by which EPA Missed Deadlines for Title I-, 

III-, and IV-Related Requirements 9

Table 4: Status of Requirements Related to Title I of the Clean Air 

Act Amendments of 1990 as of April 2005 15

Table 5: Length of Time by which Title I-Related Requirements with 

Statutory Deadlines Were Met Late 16

Table 6: Title I-Related Requirements with Statutory Deadlines Not 

Met by EPA as of April 2005 18

Table 7: Status of Requirements under Title III of the Clean Air Act 

Amendments of 1990 as of April 2005 21

Table 8: Length of Time by which Title III Requirements with 

Statutory Deadlines Were Met Late 22

Table 9: Title III Requirements Not Met by EPA as of April 2005 23

Table 10: Status of Requirements under Title IV of the Clean Air Act 

Amendments of 1990 as of April 2005 26

Table 11: Length of Time by which Title IV Requirements with 

Statutory Deadlines Were Met Late 26
Contents

Page ii GAO-05-613 Clean Air Act

Figure Figure 1: Comparison of Growth Areas and Emissions of Six Air 

Pollutants in the United States 6

Abbreviations

EPA Environmental Protection Agency

MACT Maximum Achievable Control Technology

NAAQS National Ambient Air Quality Standard

SIP State Implementation Plan

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Page 1 GAO-05-613 Clean Air Act

United States Government Accountability Office

Washington, D.C. 20548

A

May 27, 2005 Letr

The Honorable James M. Inhofe

Chairman

Committee on Environment and Public Works

United States Senate

The Honorable George V. Voinovich

Chairman

Subcommittee on Clean Air, Climate Change, and Nuclear Safety

Committee on Environment and Public Works

United States Senate

Exposure to air pollution is associated with numerous effects on human 

health, including respiratory problems, heart and lung diseases resulting in 

hospitalization, and even premature death. While air quality in the United 

States has steadily improved over the last few decades, more than a 

hundred million Americans continue to live in communities where 

pollution causes the air to be unhealthy at times, according to the 

Environmental Protection Agency (EPA). The Clean Air Act, first passed in 

1963, was last reauthorized and amended by the Congress in 1990, when 

new programs were created and changes were made to the ways in which 

air pollution is controlled. For example, the 1990 amendments created a 

market-based “cap-and-trade” program to reduce the adverse effects of 

acid rain deposition by capping emissions of sulfur dioxide nationwide and 

allowing electric power plants the flexibility to either achieve emissions 

reductions themselves or purchase allowances from plants that have 

achieved greater reductions than required. In addition, the 1990 

amendments required EPA to take numerous actions, such as creating 

national technology-based standards for hazardous air pollutants;1

 issuing 

new regulations and guidance documents; undertaking research studies; 

and preparing reports to the Congress.

1

Maximum achievable control technology (MACT) standards are technology-based 

standards developed to control the emissions of certain air toxics from numerous industry 

source categories and are based on emissions levels that are already being achieved by the 

better-controlled and lower-emitting sources in each category.
Page 2 GAO-05-613 Clean Air Act

As we reported in 2000, the first six titles of the 1990 amendments included 

hundreds of requirements for EPA and other parties—such as states and 

local governments—to take steps that will ultimately reduce air pollution.2

The amendments also established deadlines for many of these 

requirements. We further reported that EPA had met many of the 

requirements by February 2000, but that the agency had missed statutory 

deadlines for most of the requirements that were met. Some of the 

requirements EPA had not yet met had statutory deadlines after February 

2000.

In recent years, EPA and the Congress have sought to achieve further 

reductions in the emissions of sulfur dioxide and nitrogen oxides from 

power plants in order to, among other things, help improve air quality in 

communities that do not meet EPA’s health-based standards for major 

pollutants. In addition, EPA and the Congress have sought to reduce 

mercury emissions from coal-fired power plants for the first time. In fact, in 

March 2005, EPA issued two regulations—the Clean Air Interstate Rule and 

the Clean Air Mercury Rule—addressing these pollutants. The interstate 

rule permanently caps emissions of sulfur dioxide and nitrogen oxides in 28 

eastern states and the District of Columbia, and the mercury rule sets 

nationwide limits on mercury emissions from coal-fired power plants. In 

these rules, EPA uses the cap-and-trade approach to allow power plants to 

either reduce emissions or buy allowances from other power plants that 

have reduced their emissions below their limit. As you know, certain 

proposals of the current session of Congress, such as the “Clear Skies” bill, 

would similarly impose reductions of sulfur dioxide, nitrogen oxides, and 

mercury, though they would do so on a nationwide basis for all three 

pollutants.3

 Some proponents of the legislative approach to controlling 

emissions have argued that legislation that specified emissions reduction 

levels may be subject to fewer legal challenges than EPA-promulgated 

regulations developed under broader statutory authorities. Along these 

lines, we note that on the day EPA issued the mercury rule, attorneys 

general for nine states initiated a lawsuit challenging various aspects of this 

rule.

2

GAO, Air Pollution: Status of Implementation and Issues of the Clean Air Act 

Amendments of 1990, GAO/RCED-00-72 (Washington, D.C.: April 17, 2000).

3

Versions of the Clear Skies proposal are represented by bills S. 131 and H.R. 227. Bills that 

differ, among other aspects, in that they would also cap carbon dioxide, include S.150 and 

H.R. 1451.
Page 3 GAO-05-613 Clean Air Act

In this context, you asked us to report on the current status of EPA’s 

implementation of requirements under Titles I, III, and IV of the Clean Air 

Act Amendments of 1990, which address national ambient (outdoor) air 

quality standards, hazardous air pollutants, and acid deposition control, 

respectively, and are the most relevant to the recent regulations and 

proposed legislation addressing emissions of air pollutants by power 

plants.

To obtain information on the status of EPA’s implementation of Titles I, III, 

and IV of the Clean Air Act Amendments of 1990, we spoke with EPA 

officials knowledgeable about EPA’s workload related to these titles. These 

officials verified a list of the requirements related to each title for accuracy 

and completeness and provided documentation for any changes made to 

the list. This list had originally been developed as evidence for GAO’s 2000 

report on the status of EPA’s implementation of the 1990 amendments.4

 In 

addition, EPA officials provided explanations and documentation for 

requirements that had not been met as of April 2005. This report focuses on 

the extent to which EPA has met its requirements with statutory deadlines 

prior to April 2005 and those without statutory deadlines related to Titles I, 

III, and IV under the 1990 amendments, but does not show the extent to 

which the states have implemented applicable requirements. A more 

detailed description of our scope and methodology is presented in 

appendix IV. We conducted our work from January 2005 to May 2005 in 

accordance with generally accepted government auditing standards.

Results in Brief As of April 2005, EPA had completed all but 48 of the 452 actions that the 

agency identified as required to meet the objectives of Titles I, III, and IV of 

the Clean Air Act Amendments of 1990. The number, scope, and complexity 

of the required actions under each of these titles varied widely, and these 

differences, along with other challenges EPA faced, led to varying 

timeliness in implementing these requirements. Some of the major actions 

that EPA has taken related to these three titles include reviewing state 

plans for achieving national health- and welfare-based standards for six 

major air pollutants, developing technology-based standards for 174 

separate categories of sources of hazardous air pollutants, and 

implementing a market-based cap-and-trade program to reduce emissions 

of sulfur dioxide from power plants. Of the 404 actions completed, 338 had 

4

See footnote 2. 
Page 4 GAO-05-613 Clean Air Act

statutory deadlines prior to April 2005, most of which EPA did not meet on 

time. In fact, EPA completed 256 of these actions late: many (162) 2 years 

or less after the required date, but others (94) more than 2 years after their 

deadlines. Consequently, improvements in air quality associated with some 

of these requirements may have been delayed. According to EPA officials, 

the agency missed these deadlines for several reasons, including an 

emphasis on stakeholders’ review and involvement during regulatory 

development; the necessity to set priorities among the actions required of 

EPA resulting from the 1990 amendments; and competing demands caused 

by the workload associated with EPA’s response to lawsuits challenging 

some of its rules. EPA officials explained that 45 of the requirements with 

statutory deadlines were still unmet as of April 2005 because of competing 

priorities, among other factors. For example, 15 requirements for EPA to 

limit emissions of volatile organic compounds from various products, such 

as cleaning products and insecticides, were not completed because the 

agency shifted its priorities toward implementing standards related to the 

emissions of hazardous air pollutants regulated under Title III, according to 

EPA officials. In addition, EPA has not implemented 19 actions required 

under Title III to assess whether EPA’s emissions standards for certain 

sources of hazardous air pollutants appropriately protect public health. 

Any improvements in air quality that would result from EPA meeting these 

requirements remain unrealized.

Background The Clean Air Act, a comprehensive federal law that regulates air pollution 

from stationary and mobile sources, was passed in 1963 to improve and 

protect the quality of the nation’s air. The act was substantially overhauled 

in 1970 when the Congress required EPA to establish national ambient air 

quality standards for pollutants at levels that are necessary to protect 

public health with an adequate margin of safety and to protect public 

welfare from adverse effects. EPA has set such standards for ozone, carbon 

monoxide, particulate matter, sulfur oxides, nitrogen dioxide, and lead. In 

addition, the act directed the states to specify how they would achieve and 

maintain compliance with the national standard for each pollutant. The 

Congress amended the act again in 1977 and 1990. The 1977 amendments 

were passed primarily to set new goals and dates for attaining the 

standards because many areas of the country had failed to meet the 

deadlines set previously. The act was amended again in 1990 when several 

new themes were incorporated into it, including encouraging the use of 

market-based approaches to reduce emissions, such as cap-and-trade 

programs.
Page 5 GAO-05-613 Clean Air Act

The major provisions of the 1990 amendments are contained in the first six 

titles. As requested, this report addresses EPA’s actions related to Titles I, 

III, and IV:5

• Title I establishes a detailed and graduated program for the attainment 

and maintenance of the national ambient air quality standards;

• Title III expands and modifies regulations of hazardous air pollutant 

emissions and establishes a list of 189 hazardous air pollutants to be 

regulated;

• Title IV establishes the acid deposition control program to reduce the 

adverse effects of acid rain by reducing the annual emissions of 

pollutants that contribute to it.6

Although the Clean Air Act is a federal law, states and local governments 

are responsible for carrying out certain portions of the statute. For 

example, states are responsible for developing implementation plans that 

describe how they will come into compliance with national standards set 

by EPA. EPA must approve each state’s plan, and if an implementation plan 

is not acceptable, EPA may assume enforcement of the Clean Air Act in 

that state. Once EPA sets a national standard, it is generally up to state and 

local air pollution control agencies to enforce the standard, with oversight 

from EPA. For example, state air pollution control agencies may hold 

hearings on permit applications by power or chemical plants. States may 

also fine companies for violating air pollution limits.

According to EPA, by many measures, the quality of the nation’s air has 

improved in recent years. Each year EPA estimates emissions that impact 

the ambient concentrations of the six major air pollutants for which EPA 

sets national ambient air quality standards. EPA uses these annual 

emissions estimates as one indicator of the effectiveness of its air 

programs. As figure 1 shows, according to EPA, between 1970 and 2004, 

5

Other titles contain provisions for controlling air pollution from motor vehicles, engines, 

and their fuel (Title II), establishing a national permit program to ensure compliance with all 

applicable requirements of the act (Title V), and protecting the stratospheric ozone layer 

(Title VI). 

6

Acid rain is the result of sulfur dioxide and nitrogen oxides reacting in the atmosphere with 

water and returning to earth as rain, fog, or snow. Acid rain is also referred to as acid 

deposition, which is the process by which acidic particles, gases, and precipitation leave the 

atmosphere.
Page 6 GAO-05-613 Clean Air Act

gross domestic product, vehicle miles traveled, energy consumption, and 

U.S. population all grew; during the same time period, however, total 

emissions of the six principal air pollutants dropped by 54 percent.

Figure 1: Comparison of Growth Areas and Emissions of Six Air Pollutantsa in the 

United States

a

Ozone, carbon monoxide, particulate matter, sulfur oxides, nitrogen dioxide, and lead.

Note: This figure represents data for the years 1970, 1980, 1990, and 1995 through 2004.

Year

Percentage

Source: EPA.

-100

-50

0

50

100

150

200

Aggregate emissions

Energy consumption

Gross domestic product

Vehicle miles traveled

U.S. population

1970 1980 1990 2000 2004

-54

40

171

47

187
Page 7 GAO-05-613 Clean Air Act

Despite this progress, large numbers of Americans continue to live in 

communities where pollution sometimes exceeds federal air quality 

standards for one or more of the six principal air pollutants. For example, 

EPA reported in April 2004 that 159 million people lived in areas of the 

United States where air pollution sometimes exceeds federal air quality 

standards for ground-level ozone.7

 According to EPA, exposure to ozone 

has been linked to a number of adverse health effects, including significant 

decreases in lung function; inflammation of the airways; and increased 

respiratory symptoms, such as cough and pain when taking a deep breath. 

Moreover, in 2003, 62 million people lived in counties where monitors 

showed particle pollution levels higher than national particulate matter 

standards, according to a December 2004 EPA report.8

 Long-term exposure 

to particle pollution is associated with problems such as decreased lung 

function, chronic bronchitis, and premature death. Even short-term 

exposure to particle pollution—measured in hours or days—is associated 

with such effects as cardiac arrhythmias (heartbeat irregularities), heart 

attacks, hospital admissions or emergency room visits for heart or lung 

disease, and premature death.

EPA Has Implemented 

Almost All Required 

Actions, but Many 

Were Implemented 

Late

EPA identified 452 actions required to meet the objectives of Titles I, III, 

and IV of the Clean Air Act Amendments of 1990. About half of these 

required actions were included under Title III, which also included the 

largest number of requirements with statutory deadlines. As shown in table 

1, the 1990 amendments specified statutory deadlines for 338 of the Title I-, 

III-, and IV-related requirements. 

7

EPA, The Ozone Report: Measuring Progress through 2003 (EPA 454/ K-04-001, April 

2004). These “nonattainment” areas included areas that had violated the ozone standard or 

contributed to violations of this standard.

8

EPA, The Particle Pollution Report: Current Understanding of Air Quality and 

Emissions through 2003 (EPA 454-R-04-002, December 2004).
Page 8 GAO-05-613 Clean Air Act

Table 1: Requirements with and without Statutory Deadlines as of April 2005, by 

Related Title

Source: GAO analysis of EPA data. 

Note: This table does not include data on certain Title III actions—residual risk and other reviews with 

deadlines after April 2005.

The numerous actions required to meet the objectives of Titles I, III, and IV 

of the 1990 amendments vary in scope and complexity. For example, Title I 

of the Clean Air Act requires EPA to periodically review and revise, as 

appropriate, the national health- and welfare-based standards for air 

quality. After EPA revises any one of these standards, states are responsible 

for developing plans that detail how they will achieve the revised standard. 

EPA then must review the individual state plans for each standard and 

decide whether to approve them. While EPA must review and approve all 

individual state plans submitted, each set of reviews is only counted as one 

action. Other Title I requirements, on the other hand, only require EPA to 

publish reports on air quality and emission trends. While the reports may 

represent a significant amount of effort, the steps required to implement 

national ambient air quality standards are inherently more difficult to 

accomplish and often require parties independent of EPA, such as state and 

local agencies, to pass legislation and issue, adopt, and implement rules. 

Comparing the requirements among titles also shows how they vary in 

complexity. For example, Title IV required EPA to develop a new 

market-based cap and trade program to reduce emissions of sulfur dioxide 

and a rate-based program to reduce emissions of nitrogen oxides from 

power plants. While developing the cap and trade program was a large 

undertaking on EPA’s part, it involved regulating a specified number of 

stationary sources in a single industry. In contrast, under Title III, EPA is 

required to implement technology-based standards for 174 separate 

categories of sources of hazardous air pollutants, involving many 

industries. 

As shown in table 2, a large portion of the requirements with statutory 

deadlines related to Titles I, III, and IV were met late. That is, 256 of the 338 

requirements with statutory deadlines have been completed but were late. 

Type of requirement Title I Title III Title IV Total

Requirements with statutory 

deadlines 83 229 26 338

Requirements without statutory 

deadlines 88 8 18 114

Total 171 237 44 452
Page 9 GAO-05-613 Clean Air Act

Of the 114 requirements without statutory deadlines, all but 3 of the 

requirements have been completed. 

Table 2: Status of Title I-, III-, and IV-Related Requirements as of April 2005

Source: GAO analysis of EPA data.

Note: This table does not include data on certain Title III actions—residual risk and other reviews with 

deadlines after April 2005. 

On average, EPA met the requirements related to Titles I, III, and IV about 

24, 25, and 15 months after their statutory deadlines, respectively. Of the 

256 requirements that EPA met late, 162 were met within 2 years of their 

statutory deadline and 94 were completed more than 2 years after their 

deadlines (see table 3). Consequently, improvements in air quality 

associated with some of these requirements may have been delayed.

Table 3: Length of Time by which EPA Missed Deadlines for Title I-, III-, and 

IV-Related Requirements

Source: GAO analysis of EPA data.

Type of requirement Title I Title III Title IV Total

Requirements with statutory deadlines

 Met on time 16 13 8 37

 Met late 45 195 16 256

 Unmet – deadlines prior to April 

2005

22 21 2 45

Subtotal 83 229 26 338

Requirements without statutory deadlines

Completed 85 8 18 111

Not completed 3 0 0 3

Subtotal 88 8 18 114

Total 171 237 44 452

Length of time Title I Title III Title IV Total

Up to 12 months 24 41 10 75

13 to 24 months 9 75 3 87

25 to 36 months 4 50 2 56

Over 36 months 8 29 1 38

Total 45 195 16 256
Page 10 GAO-05-613 Clean Air Act

EPA officials cited several factors to explain why the agency missed 

deadlines for so many requirements. Among these factors was an emphasis 

on stakeholders’ review and involvement during regulatory development, 

which added to the time needed to issue regulations. For example, 

according to an EPA official, the process to develop an early technology 

rule under Title III involved protracted negotiations among EPA, industry 

groups, a labor union, and environmental groups. The rule was finalized in 

October 1993, 10 months after its statutory deadline. In addition, EPA 

officials mentioned the need to set priorities among the tremendous 

number of new requirements for EPA resulting from the 1990 amendments, 

which meant that some of these actions had to be delayed. Moreover, 

competing demands caused by the workload associated with EPA’s 

responses to lawsuits challenging some of its rules caused additional 

delays. For example, the time needed to respond to litigation of previous 

rules impinged on EPA staff’s ability to develop new rules, according to 

agency officials. In addition, at the time of our 2000 report, EPA officials 

also attributed delays to the emergence of new scientific information that 

led to major Clean Air Act activities unforeseen by the 1990 amendments. 

For example, the emergence of new scientific information regarding the 

importance of regional ozone transport led to an extensive collaborative 

process between states in the eastern half of the country to evaluate and 

address the transport of ozone and its precursors.

As of April 2005, 45 of the requirements related to Titles I, III, and IV with 

statutory deadlines that had passed have not been met. Thus, any 

improvements in air quality that would result from EPA meeting these 

requirements remain unrealized. The majority of the unmet requirements 

related to Title I are activities involving promulgating regulations that limit 

the emissions of volatile organic compounds from different groups of 

consumer and commercial products. According to EPA officials, these 

rules were never completed because EPA shifted its priorities toward 

issuing the Title III technology-based standards. Additionally, EPA officials 

noted that many states have implemented their own rules limiting 

emissions of volatile organic compounds from these products, and these 

state rules are achieving the level of emissions reductions that would be 

achieved by a national rule passed by EPA. However, EPA is currently being 

sued because it did not implement these rules by their statutory deadlines. 

According to an EPA official, the agency and the litigant have agreed on the 

actions to be taken to address the requirements, but they could not reach 

agreement on completion dates. As a result, EPA is currently awaiting 

court-issued compliance dates. In addition, 21 Title III requirements have
Page 11 GAO-05-613 Clean Air Act

yet to be met.9 Most of these are “residual risk” reviews of 

technology-based standards with deadlines prior to April 2005. That is, 

within 8 years of setting each technology-based standard, EPA is required 

to assess the remaining health risks (the residual risk) from each source 

category to determine whether the standard appropriately protects public 

health. Applying this “risk-based” approach, EPA must revise the standards 

to make them more protective of health, if necessary. EPA completed its 

first review and issued the first set of these risk-based amendments in 

March 2005. Two actions required by Title IV have not been met, but, 

according to EPA, the agency has decided not to pursue these actions 

further. The requirements were to (1) promulgate an opt-in regulation for 

process sources and (2) conduct a sulfur dioxide/nitrogen oxides 

inter-pollutant trading study. According to EPA officials, the agency 

decided not to promulgate the opt-in regulation because it determined that 

the federal resources needed to develop the rule would be well in excess of 

those available and the implementation of this provision would not reduce 

overall emissions. EPA officials also said that the rule would not be 

cost-effective due to these factors and the limited number of sources 

expected to use the opt-in option. EPA officials said that the agency 

decided not to pursue the sulfur dioxide/nitrogen oxides inter-pollutant 

study because of the lack of a trading ratio that would capture the complex 

environmental relationship between sulfur dioxide and nitrogen oxides and 

because an inter-pollutant trading program would be complex and unlikely 

to result in environmental benefits.

The list of specific actions EPA is required to take to meet the objectives of 

Titles I and III of the Clean Air Act Amendments of 1990 includes 

requirements for periodic assessments of some of the standards related to 

these titles. Under the Clean Air Act, EPA is required every 5 years to 

review the levels at which it has set national ambient air quality standards 

to ensure that they are sufficiently protective of public health and welfare. 

If EPA determines it is necessary to revise the standard, the agency 

undertakes a rulemaking to do so. Each new national ambient air quality 

standard, in turn, will trigger a number of subsequent EPA actions under 

Title I, such as setting the boundaries of areas that do not attain the 

standards and approving state plans to correct nonattainment. As a result, 

the set of required actions related to Title I tends to repeat over time. Title 

9

This number does not include those residual risk reviews that were not yet due as of April 

2005, nor does it include recurring reviews of MACT standards to account for improvements 

in air pollution controls and prevention, as discussed further in appendix II.
Page 12 GAO-05-613 Clean Air Act

III also includes requirements for periodic assessments of its 

technology-based standards. In addition to the residual risk assessments 

discussed above, the Clean Air Act requires that EPA review the 

technology-based standards every 8 years, and, if necessary, revise them to 

account for improvements in air pollution controls and prevention. The 

first round of these recurring reviews will occur concurrently with the first 

round of residual risk assessments, according to an EPA official. Moreover, 

EPA’s workload related to its air programs may increase as a result of 

recommendations for regulatory reform compiled by the Office of 

Management and Budget. For example, in response to a recommendation 

to permit the use of new technology to monitor leaks of volatile air 

pollutants, EPA plans to propose a rule or guidance in March 2006.

Observations The Clean Air Act Amendments of 1990 constituted a significant overhaul 

of the Clean Air Act, and notable reductions in emissions of air pollutants 

have been attained as a result of the many actions these amendments 

required of EPA, states, and other parties. Currently, EPA has completed 

most of the 452 actions required by the 1990 amendments related to Titles I, 

III, and IV. The number, scope, and complexity of the required actions 

under each of these titles varied widely, and these differences, along with 

other challenges EPA faced, led to varying timeliness in implementing 

these requirements. Although EPA did not meet the statutory deadlines in 

many cases, we believe that the deadlines played an important role in EPA’s 

implementation of the myriad and diverse actions mandated in the 1990 

amendments by providing a structure to guide and support the agency’s 

efforts to complete them. 

As EPA and the Congress now move on to addressing the remaining air 

pollution problems that pose health threats to our citizens, some points 

from our 2000 report on the implementation of the 1990 amendments bear 

repeating. First, some of the stakeholders we interviewed representing 

environmental groups and state and local government agencies expressed a 

preference for legislation and regulations that describe specific amounts of 

emissions to be reduced, provide specific deadlines to be met, and identify 

the sources to be regulated. Second, we, along with many of these 

stakeholders, concluded in that report that the acid rain program under 

Title IV could offer a worthwhile model for some other air quality problems 

because it set emission-reduction goals and encouraged market-based 

approaches, such as cap-and-trade programs, to attain these goals. While 

EPA officials noted that emissions-trading programs may not be suitable 

for all air pollutants, the agency has applied this approach to several 
Page 13 GAO-05-613 Clean Air Act

pollutants since 2000. Specifically, EPA has issued final rules using 

cap-and-trade programs to achieve further reductions in sulfur dioxide and 

nitrogen oxides and to require reductions of mercury emissions for the first 

time. However, whether EPA can apply the cap-and-trade model to 

hazardous air pollutants such as mercury in the absence of express 

statutory authority to do so is unclear, particularly in light of the lawsuit 

that has been filed challenging EPA’s March 2005 rule on mercury 

emissions.

Agency Comments and 

Our Evaluation

We provided EPA with a draft of this report for its review and comment. 

EPA generally agreed with the findings presented in the report and 

provided supplemental information about the air quality, public health, and 

environmental benefits associated with implementation of the Clean Air 

Act Amendments of 1990 and comments related to its future challenges. 

The agency also provided technical comments, which we incorporated 

where appropriate. Appendix V contains the full text of the agency’s 

comments and our responses.

As agreed with your office, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

date of this letter. At that time, we will send copies of this report to the 

appropriate congressional committees; the Administrator, EPA; and other 

interested parties. We will also make copies available to others upon 

request. In addition, the report will be available at no charge on the GAO 

Web site at http://www.gao.gov.

If you or your staff have any questions, please call me at (202) 512-3841. 

Key contributors to this report are listed in appendix VI.

John B. Stephenson

Director, Natural Resources

and Environment
Page 14 GAO-05-613 Clean Air Act

Appendix I

Title I ApApenednxidexiIs

The Clean Air Act requires that all areas of the country meet national 

ambient air quality standards (NAAQS), which are set by EPA at levels that 

are expected to be protective of human health and the environment. 

NAAQS have been established for six “criteria” pollutants: ozone, carbon 

monoxide, nitrogen dioxide, sulfur oxides, particulate matter, and lead. The 

act further specifies that EPA must assess the level at which the standards 

are set every five years and revise them, if necessary. 

To accomplish the objectives of Title I of the Clean Air Act Amendments of 

1990, EPA identified 171 requirements.1

 The specific requirements 

contained in Title I direct EPA to perform a variety of activities, many of 

which are related to implementing the NAAQS. Implementation of the 

standards involves several stages, many requiring efforts by both EPA and 

states. For example, once EPA has determined the appropriate air quality 

level at which to set a standard, the agency then goes through a designation 

process during which it identifies the areas of the country that fail to meet 

the standard. After the nonattainment areas are identified, states have 

primary responsibility for attaining and maintaining the NAAQS. To do this, 

states develop state implementation plans (SIPs) that specify the programs 

that states will develop to achieve and maintain compliance with the 

standards. Once a state submits a SIP to EPA, EPA is responsible for 

reviewing it and either approving or disapproving the plan. To assist states 

in developing their plans, EPA develops guidance documents that help 

states interpret the standards and provide information on how to comply. 

For example, EPA established several alternative control techniques 

documents for various sources that emit nitrogen oxides. These documents 

provide suggestions for states and industry on different techniques that can 

be used to reduce nitrogen oxides emissions. In some circumstances, EPA 

may provide guidance to the state and local air pollution control agencies 

through the issuance of EPA guidance and/or policy memos. For example, 

although designating areas as nonattainment or attainment is a complex 

and time-consuming process, EPA issued guidance through policy memos 

on the factors and criteria EPA used to make decisions for designating 

areas of the country as nonattainment.

1

The number of requirements identified by EPA to meet the objectives of Title I has 

increased since GAO conducted its previous study in 2000. This increase is due to the 

recurring nature of Title I-related requirements (for example, EPA must review each NAAQS 

every 5 years).
Appendix I

Title I

Page 15 GAO-05-613 Clean Air Act

As of April 2005, EPA had completed 146 of the requirements that the 

agency must implement to meet the objectives of Title I. Sixty-one 

requirements that EPA had met by April 2005 had statutory deadlines. As 

table 4 shows, EPA met 16 of these requirements on time and missed the 

deadlines for 45 of them. EPA also completed 85 of the 88 requirements 

that did not have statutory deadlines. 

Table 4: Status of Requirements Related to Title I of the Clean Air Act Amendments 

of 1990 as of April 2005

Source: GAO analysis of EPA data.

On average, Title I-related requirements that were met late were completed 

24 months after their statutory deadline. As table 5 shows, the length of 

time by which requirements were met late for Title I varied. For example, 

24 of the late requirements were met within 1 year of their statutory 

deadline while 8 requirements were completed more than 3 years late. 

Requirements with statutory deadlines Number

Met on time 16

Met late 45

Unmet – deadlines prior to April 2005 22

Subtotal 83

Requirements without statutory deadlines

Completed 85

Not completed 3

Subtotal 88

Total 171
Appendix I

Title I

Page 16 GAO-05-613 Clean Air Act

Table 5: Length of Time by which Title I-Related Requirements with Statutory 

Deadlines Were Met Late 

Source: GAO analysis of EPA data.

According to EPA, the agency missed deadlines for Title I-related 

requirements for a number of reasons, such as (1) having to review a larger 

quantity of scientific information than was available in the past; (2) 

competing demands placed on agency staff who had to work concurrently 

on more than one major rulemaking; and (3) engaging in longer, more 

involved interagency review processes. According to agency officials, many 

of the requirements that EPA completed late arose due to issues beyond 

EPA’s control. For example, in implementing the ozone and particulate 

matter NAAQS, the emergence of new scientific information regarding the 

importance of regional ozone transport led to an extensive collaborative 

process between states in the eastern half of the country to evaluate and 

address the transport of ozone and its precursors. This information was 

then taken into account in the review and subsequent revision of the ozone 

NAAQS in 1997. In addition, EPA was sued on both the 1997 ozone and 

particulate matter standards, which delayed EPA’s action to designate areas 

as nonattainment. Moreover, the ongoing review of the particulate matter 

NAAQS has been significantly extended as a consequence of the 

unprecedented amount of new scientific research that has become 

available since the last review, according to EPA.

Currently, EPA has not completed 22 requirements related to Title I with 

statutory deadlines (see table 6). Fifteen of these requirements call for 

rules involving different groups of consumer and commercial products, six 

involve reviewing the NAAQS for the criteria pollutants, and one requires 

EPA to finalize approving the state implementation plans for ozone and 

carbon monoxide. The outstanding rules involving the consumer and 

commercial products are to limit volatile organic compound emissions 

from various products, such as cleaning products, personal care products, 

and a variety of insecticides. The 1990 amendments specified that the rules 

Length of time

Number of

requirements

Up to 12 months 24

13 to 24 months 9

25 to 36 months 4

Over 36 months 8

Total 45
Appendix I

Title I

Page 17 GAO-05-613 Clean Air Act

be promulgated in four groups, based on a priority ranking established by 

EPA that includes a number of factors, such as the quantity of emissions 

from certain products. While EPA completed the first group of rules by 

September 1998, the agency had not done anything further to implement 

the remaining three groups of rules. According to EPA officials, no further 

work had been done to implement the rules because EPA shifted its 

priorities toward issuing the Title III technology-based standards. 

Additionally, EPA officials noted that many states have implemented their 

own rules limiting emissions of volatile organic compounds from these 

products, and these state rules are achieving the level of emissions 

reductions that would be achieved by a national rule passed by EPA. An 

EPA official stated that a national rule would not provide much of an 

additional benefit in the areas where emissions of volatile organic 

compounds are a problem and that a national rule would be fought by 

industry in states where emissions of volatile organic compounds are not a 

problem. However, promulgating these rules is a requirement under the 

1990 amendments, and according to EPA officials, the agency is currently 

being sued by the Sierra Club, an environmental advocacy group, for not 

promulgating them by their statutory deadline. EPA and the litigant have 

agreed on the actions to be taken to address the requirements, however, 

they could not reach agreement on the completion dates and are currently 

awaiting court-issued compliance dates. 

In addition, the other six unmet requirements related to Title I involve 

potentially revising the NAAQS for the criteria pollutants. While EPA has 

been involved in litigation regarding four of these standards, litigation is 

still ongoing only regarding the lead NAAQS. EPA is being sued for not 

reviewing since 1991 the lead NAAQS that was originally issued in October 

1978. According to EPA officials, the agency did not undertake this review 

because it shifted its focus to controlling other sources of lead, such as 

drinking water and hazardous waste facilities. As shown in table 6, EPA 

expects to complete the required reviews for four of the criteria pollutants 

by 2009.
Appendix I

Title I

Page 18 GAO-05-613 Clean Air Act

Table 6: Title I-Related Requirements with Statutory Deadlines Not Met by EPA as of April 2005

Source: GAO analysis of EPA data.

Description of requirements

Type of 

requirement Statutory deadline Projected completion date

Consumer and Commercial Products—Group 2—Flex 

package printing

Regulation March 1999 Unknown

Consumer and Commercial Products—Group 3—Aerosol 

spray paints

Regulation March 2001 Unknown

Consumer and Commercial Products—Group 3—Industrial 

cleaning solvents

Regulation March 2001 Unknown

Consumer and Commercial Products—Group 3—Flat wood 

paneling

Regulation March 2001 Unknown

Consumer and Commercial Products—Group 3—

Lithographic printing

Regulation March 2001 Unknown

Consumer and Commercial Products—Group 4—Paper, 

film, and foil coatings

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—

Letterpress printing

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Plastic 

parts

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Metal 

furniture

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Auto and 

light duty trucks assembly

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Petroleum 

dry-cleaning

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Misc 

metal parts

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Large 

appliances

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Fiberglass 

boat manufacturing

Regulation March 2003 Unknown

Consumer and Commercial Products—Group 4—Misc 

industrial adhesives

Regulation March 2003 Unknown

Promulgate decision on ozone NAAQS Regulation July 2002 December 2007

Promulgate decision on particulate matter NAAQS Regulation July 2002 September 2006

Promulgate decision on sulfur oxides NAAQS Regulation May 1991 Unknown

Promulgate decision on carbon monoxide NAAQS Regulation August 1999 May 2009

Promulgate decision on nitrogen dioxide NAAQS Regulation October 1991 Unknown

Promulgate decision on lead NAAQS Regulation 1996a June 2009

Approve or disapprove state implementation plans for ozone 

and carbon monoxide

Regulation November 1994b September 2005
Appendix I

Title I

Page 19 GAO-05-613 Clean Air Act

Note: Consumer and commercial product requirements have been issued either as regulations or as 

guidelines in the past.

a

EPA provided only the year of this statutory deadline.

b

There was more than one statutory deadline for this requirement. This table presents the latest 

deadline.

In addition to the unmet requirements discussed above, EPA has three 

requirements related to Title I without statutory deadlines that have not yet 

been completed. The first is to develop a proposed particulate matter 

implementation rule, which EPA expects to complete in summer 2005. The 

second is the promulgation of methods for measurement of visible 

emissions; EPA has not yet set a completion date for this action. The third 

is the promulgation of phase II of the 8-hour ozone implementation rule, 

expected in summer 2005.
Page 20 GAO-05-613 Clean Air Act

Appendix II

Title III ApendxiI

Title III of the Clean Air Act Amendments of 1990 established a new 

regulatory program to reduce the emissions of hazardous air pollutants, 

specifying 189 air toxics whose emissions would be controlled under its 

provisions. The list includes organic and inorganic chemicals, compounds 

of various elements, and numerous other toxic substances that are 

frequently emitted into the air. Title III was intended to reduce the 

population’s exposures to these pollutants, which can cause serious 

adverse health effects such as cancer and reproductive dysfunction. After 

identifying the pollutants to be regulated, Title III directs EPA to impose 

technology-based standards, or Maximum Achievable Control Technology 

(MACT) standards, on industry to reduce emissions.These technologybased standards require the maximum degree of reduction in emissions 

that EPA determines achievable for new and existing sources, taking into 

consideration the cost of achieving such reduction, health and 

environmental impacts, and energy requirements. The process for 

developing each MACT standard may include surveying impacted 

industries, visiting sites, testing emissions, and conducting public hearings. 

As a second step, within 8 years after completing each technology-based 

standard, EPA is to review the remaining risks to the public and, if 

necessary, issue health-based amendments to each of the MACT rules to 

address such risks. The first set of these “residual risk” standards was 

finalized in March 2005; residual risk standards for the remaining MACT 

rules have not been completed. Finally, the Clean Air Act requires that EPA 

review and, if necessary, revise the technology-based standards at least 

every 8 years, to account for improvements in air pollution controls and 

prevention. The first round of these recurring reviews will occur 

concurrently with the first round of residual risk assessments, according to 

an EPA official.

EPA identified 237 requirements—either with statutory deadlines prior to 

April 2005 or without statutory deadlines—that accomplish the objectives 

of Title III of the Clean Air Act Amendments of 1990.1

 Most of the specific 

requirements under Title III direct EPA to promulgate MACT standards for 

various sources of hazardous air pollutants, such as dry cleaning facilities, 

petroleum refineries, and the printing and publishing industry. Title III also 

requires EPA to issue a variety of studies and reports to the Congress. For 

example, EPA has issued a series of studies on the deposition of air 

1

The number of requirements identified by EPA to meet the objectives of Title III has 

increased since GAO conducted its previous study in 2000. This change in the number of 

requirements is due to the inclusion of residual risk reviews, among other factors.
Appendix II

Title III

Page 21 GAO-05-613 Clean Air Act

pollutants to the Great Lakes and other bodies of water. In addition, Title III 

also directs EPA to issue guidance on a number of subjects, including, for 

example, guidance regarding state air toxics programs.

As of April 2005, EPA had met almost all of the requirements it identified to 

fully implement the objectives of Title III of the Clean Air Act Amendments 

of 1990, as shown in table 7. EPA’s most recent data show that it has taken 

the required action to meet 216 of the 237 Title III requirements, although 

195 of these were met late, as shown in table 7.

Table 7: Status of Requirements under Title III of the Clean Air Act Amendments of 

1990 as of April 2005

Source: GAO analysis of EPA data.

Notes: This table does not include data on residual risk reviews with deadlines after April 2005. It also 

does not separately count recurring reviews of MACT standards to account for improvements in air 

pollution controls and prevention; the first round of these reviews will occur concurrently with EPA’s 

residual risk reviews.

As shown above, the vast majority of Title III requirements were met late. 

On average, Title III requirements met late were completed 25 months after 

their statutory deadline. However, the length of time by which 

requirements were met late varied. As shown in table 8, 116 of the 195 

requirements met late were completed within the first 2 years after the 

statutory deadline, while 29 were not completed until more than 3 years 

after the deadline. 

Requirements with statutory deadlines Number

Met on time 13

Met late 195

Unmet 21

Subtotal 229

Requirements without statutory deadlines

Completed 8

Not completed 0

Total 237
Appendix II

Title III

Page 22 GAO-05-613 Clean Air Act

Table 8: Length of Time by which Title III Requirements with Statutory Deadlines 

Were Met Late

Source: GAO analysis of EPA data.

In explaining why requirements under Title III were met late, an EPA 

official discussed several factors. For example, the official said that the 

vast majority of the requirements involved the development of the MACT 

standards, which requires a significant amount of time and effort. The 

official also confirmed the reasons that requirements were met late 

provided by EPA officials at the time of our 2000 report, which included the 

need to prioritize, given resource limitations, the time needed to develop 

the policy framework and infrastructure of the MACT program, and the 

need for stakeholder participation in the rulemaking processes for certain 

MACT standards. In addition, the EPA official pointed out that in the past, 

litigation on issued rules has imposed additional demands on EPA staff 

working to meet outstanding requirements, leading to delays.

There are 21 requirements under Title III that EPA had not met as of April 

2005, most of which involve the residual risk reviews required after EPA 

has set technology-based standards (see table 9). Specifically, EPA has not 

yet reviewed residual risk for 19 MACT standards with deadlines prior to 

April 2005. EPA completed its first review and issued the first set of these 

risk-based amendments, for the coke oven batteries MACT standard, on 

March 31, 2005.2

 In addition to the residual risk reviews, EPA has not yet 

completed its urban area source standards.3

 The other unmet requirement 

under Title III calls for EPA to promulgate standards for solid waste 

Length of time

Number of

requirements

Up to 12 months 41

13 to 24 months 75

25 to 36 months 50

Over 36 months 29

Total 195

2

Coke ovens convert coal to coke which is used to produce iron at steel mills and foundries. 

A coke oven battery consists of a group of ovens connected by common walls.

3

While EPA has completed area source standards for 15 of 70 categories of sources that emit 

over 30 different hazardous air pollutants, 50 of the remaining source categories are under 

litigation, and the remaining 5 categories have court-ordered deadlines for implementation. 
Appendix II

Title III

Page 23 GAO-05-613 Clean Air Act

incinerators not previously regulated under the title. According to an EPA 

official, the agency has focused its resources on regulating major solid 

waste incinerators, while this requirement consists of a “catch-all” to pick 

up remaining sources. Part of the challenge to completing this action has 

involved identifying what these other sources might be, according to the 

official.

Table 9: Title III Requirements Not Met by EPA as of April 2005

Description of requirements Type of requirement

Statutory 

deadline Projected completion date

Promulgation of urban area source standards Regulation November 2000 Unknown

Promulgation of standards for “other” solid waste 

incinerators

Regulation November 2000 November 2005

Residual risk review for perchlorethylene emissions from 

dry cleaning facilities

Regulation September 2001 April 2006

Residual risk review for organic hazardous air pollutants 

from the synthetic organic chemical manufacturing 

industry and other processes subject to the negotiated 

regulation for equipment leaks

Regulation April 2002 December 2006

Residual risk review for industrial process cooling towers Regulation September 2002 March 2006

Residual risk review for ethylene oxide commercial 

sterilization and fumigation operations

Regulation December 2002 March 2006

Residual risk review for gasoline distribution (stage 1) Regulation December 2002 March 2006

Residual risk review for halogenated solvent cleaning Regulation December 2002 December 2006

Residual risk review for magnetic tape manufacturing 

operations

Regulation December 2002 March 2006

Residual risk review for chromium emissions from hard 

and decorative chromium electroplating and chromium 

anodizing tanks

Regulation January 2003 Unknown

Residual risk review for epoxy resins production and nonnylon polyamides productionRegulation March 2003 Unknown

Residual risk review for secondary lead smelting Regulation June 2003 Unknown

Residual risk review for petroleum refineries Regulation August 2003 Unknown

Residual risk review for aerospace manufacturing and 

rework facilities

Regulation September 2003 Unknown

Residual risk review for marine tank vessel loading 

operations

Regulation September 2003 Unknown

Residual risk review for shipbuilding and ship repair 

(surface coating) operations

Regulation December 2003 Unknown

Residual risk review for wood furniture manufacturing 

operations

Regulation December 2003 Unknown
Appendix II

Title III

Page 24 GAO-05-613 Clean Air Act

Source: GAO analysis of EPA data.

Note: The Clean Air Act requires EPA to review MACT standards at least every 8 years and revise 

them, if necessary, to account for improvements in air pollution controls and prevention; the first round 

of these reviews will occur concurrently with EPA’s residual risk reviews.

In addition to the unmet requirements above, EPA has not yet completed 

residual risk reviews for 76 MACT standards whose deadlines fall later than 

April 2005. Because these residual risk reviews are not due until 8 years 

after the completion of each technology standard, some of these residual 

risk reviews are not due until 2012.

Residual risk review for printing and publishing industry Regulation May 2004 Unknown

Residual risk review for off-site waste and recovery 

operations

Regulation July 2004 Unknown

Residual risk review for group I polymers and resins Regulation September 2004 Unknown

Residual risk review for group IV polymers and resins Regulation September 2004 Unknown

(Continued From Previous Page)

Description of requirements Type of requirement

Statutory 

deadline Projected completion date
Page 25 GAO-05-613 Clean Air Act

Appendix III

Title IV ApendxiI

Title IV of the Clean Air Act Amendments of 1990 established the acid 

deposition control program. This program was designed to provide 

environmental and public health benefits through reductions in emissions 

of sulfur dioxide and nitrogen oxides, the primary causes of acid rain. The 

program provides an alternative to traditional “command and control” 

regulatory approaches by using a market-based trading program that 

allocates sulfur dioxide emission allowances to affected electric utilities. 

The program creates a cost-effective way for utilities to achieve their 

required sulfur dioxide emission reductions in the manner that is most 

suitable to them. Utilities can choose to buy, sell, or bank their allowances, 

as long as their annual emissions do not exceed the amount of allowances 

(whether originally allocated to them or purchased) that they hold at the 

end of the year.1

 The nitrogen oxides program, on the other hand, does not 

cap emissions of nitrogen oxides, nor does it utilize an allowance trading 

system. Rather, this program, which focuses on emissions of nitrogen 

oxides from coal-fired electric utility boilers, provides flexibility for 

utilities in meeting emission limits by focusing on the emission rate to be 

achieved and providing options for compliance.

To accomplish the objectives of Title IV of the Clean Air Act Amendments 

of 1990, EPA identified 44 requirements. Many of the required activities had 

to do with setting up the acid rain program—for example, conducting 

allowance auctions, issuing allowances to utilities, and establishing an 

allowance trading system. Additionally, EPA developed requirements for 

utilities to continuously monitor their emission levels to properly account 

for allowances. 

As of April 2005, EPA had completed 42 of the 44 requirements to meet the 

objectives of Title IV. There were 26 requirements in Title IV with statutory 

deadlines—EPA met 8 of them on time and missed 16; 2 others were unmet. 

There were 18 requirements that did not have statutory deadlines, and EPA 

has completed all of them. (See table 10.)

1

The total amount of allowances allocated for all sources comprise the national cap for 

sulfur dioxide, and sources whose emissions exceed the amount of allowances held forfeit 

allowances to cover the excess emissions and must pay automatic financial penalties. 
Appendix III

Title IV

Page 26 GAO-05-613 Clean Air Act

Table 10: Status of Requirements under Title IV of the Clean Air Act Amendments of 

1990 as of April 2005

Source: GAO analysis of EPA data.

Note: Based on additional information obtained for this report, we determined that, compared with our 

2000 report, one additional requirement was met late.

On average, for the 16 requirements EPA met late, they were completed 

within approximately 15 months of their deadlines. As shown in table 11, 10 

were met within 1 year of their deadline and 1 was met more than 3 years 

late. 

Table 11: Length of Time by which Title IV Requirements with Statutory Deadlines 

Were Met Late

Source: GAO analysis of EPA data.

According to EPA officials, the agency was late with some of the 

requirements because interagency review and consultation with the Acid 

Rain Advisory Committee added time to the process. Officials consider this 

time spent worthwhile because it allowed for more stakeholder input into 

the rulemaking process, which may have made the rules less controversial. 

In fact, EPA officials stated that Title IV has been subjected to less litigation 

Requirements with statutory deadlines Number

 Met on time 8

 Met late 16

 Unmet 2

Subtotal 26

Requirements without statutory deadlines

Completed 18

Not completed 0

Total number of requirements 44

Length of time

Number of

requirements

Up to 12 months 10

13 to 24 months 3

25 to 36 months 2

Over 36 months 1

Total 16
Appendix III

Title IV

Page 27 GAO-05-613 Clean Air Act

than other titles. According to the officials, litigation, however, did cause a 

delay in the effective date of the first phase of the acid rain nitrogen oxides 

reduction program by 1 year. EPA officials said the second phase of this 

program affected approximately three times more units and was 

implemented on schedule.

EPA officials stated that since implementation of the acid rain program, 

changes have been necessary to keep the program up to date and 

successful. For example, EPA revised the continuous emission-monitoring 

rule in 1999 and 2002. According to EPA, these updates were necessary 

because of changes in the industry, such as technological advances and 

growth in the number of sources. 

Two Title IV requirements that EPA has not completed have statutory 

deadlines that have passed. The two requirements are (1) promulgating the 

opt-in regulation for process sources and (2) conducting a sulfur 

dioxide/nitrogen oxides inter-pollutant trading study. After conducting 

preliminary work for the first action, which was to have been completed by 

May 1992, EPA determined that the federal resources required to 

accomplish it were well in excess of those available. Additionally, 

according to an EPA official, there was evidence of very limited use of the 

opt-in election for other sources. Given these two factors, and EPA’s view 

that implementation of this provision would not reduce overall emissions, 

the agency determined that it would not be cost-effective to promulgate the 

regulation. Finally, EPA officials said that the agency decided not to pursue 

the second action, which was to have been completed by January 1994, for 

three reasons. Specifically, according to EPA officials, (1) they lacked a 

trading ratio that would capture the complex environmental relationship 

between sulfur dioxide and nitrogen oxides; (2) if the ratio issue could be 

resolved, an annual allowance system for nitrogen oxides would need to be 

created with which to trade sulfur dioxide allowances; and (3) it was not 

clear that implementing inter-pollutant trading would result in a net 

environmental benefit as there are multiple and complex health and 

environmental impacts of both sulfur dioxide and nitrogen oxides requiring 

a comprehensive analysis of impacts and cost-effectiveness beyond 

available resources. 
Page 28 GAO-05-613 Clean Air Act

Appendix IV

Objective, Scope, and Methodology ApendxiIV

The objective of this review was to determine the extent to which the 

Environmental Protection Agency (EPA) has completed the various actions 

required to meet the objectives of Titles I, III, and IV of the Clean Air Act 

Amendments of 1990. These titles, which respectively address national 

ambient air quality standards, hazardous air pollutants, and acid deposition 

control, are the most relevant to proposed legislation and recently finalized 

regulations that address emissions of air pollutants by power plants.

To obtain information on the status of EPA’s implementation of 

requirements related to Titles I, III, and IV of the Clean Air Act 

Amendments of 1990—both those with and without statutory deadlines—

we obtained lists of these requirements used for GAO’s 2000 report, Air 

Pollution: Status of Implementation and Issues of the Clean Air Act 

Amendments of 1990 (GAO/RCED-00-72) and held discussions with EPA 

officials knowledgeable about EPA’s workload required to meet the 

objectives of these titles. EPA officials verified the list of requirements 

related to each of the three titles for accuracy and completeness and 

provided documentation for any changes and additions made to the list.1

 To 

determine how late the requirements were met, we compared the statutory 

deadline for each requirement to the month in which the requirement was 

met. For regulations that appeared in the Federal Register, for example, we 

considered the date the Federal Register issue was published to be the date 

the requirement was met, as agreed with EPA officials.2

 In addition, we 

obtained explanations for why a large number of requirements were met 

after their statutory deadlines from two sources—our 2000 report and 

through discussions with EPA officials. For requirements that had not been 

met as of April 2005, we obtained additional information from EPA 

officials, including actions taken to date.

1

This report does not include some actions under titles I and III that EPA officials identified 

after our work was completed, the agency had reviewed and provided comments on a 

statement of facts, and EPA had provided official agency comments on the draft report (see 

app. V). The actions EPA identified, which they categorized as incomplete, involve periodic 

reviews of new source performance standards and combustion new source performance 

standards required by the Clean Air Act Amendments of 1990.

2

While agency officials agreed to use the publication date in the Federal Register as the date 

the various required actions were completed, EPA said in its comments on the draft report 

that the Office of Air and Radiation generally views the date a rule is signed and shared with 

the public as the date the agency has met its statutory obligations. The agency 

acknowledged that using the signature date would not change the report’s conclusions. 
Appendix IV

Objective, Scope, and Methodology

Page 29 GAO-05-613 Clean Air Act

To ensure the reliability of the information provided by EPA, we requested 

documentation for any changes EPA made to the list of requirements 

developed for our previous report and checked the documentation to 

ensure it matched the description of the requirement. In addition, we 

reviewed the information EPA submitted to ensure there were no duplicate 

entries or apparent inconsistencies; for any entries that appeared 

questionable, we followed up with EPA officials and usually obtained 

additional documentation. In certain cases, in particular with regard to 

Title III requirements, we also independently verified the status of the 

requirements. In all cases, EPA provided confirmation for the conclusions 

we reached as well as, in some cases, additional documentation. We 

determined that the data we obtained about the status of EPA’s 

implementation of required actions were sufficiently reliable for the 

purposes of this report. We also reviewed the methodology of two EPA 

studies that contained information about areas of the United States 

impacted by ground-level ozone and particulate matter.3

 We determined 

that these studies were sufficiently methodologically sound to present their 

results in this report as background information.

While this report addresses the extent to which EPA has met its 

requirements related to Titles I, III, and IV of the 1990 amendments, it does 

not address the status of requirements under other titles of the 

amendments or show the extent to which states have implemented 

applicable requirements. We conducted our work from January 2005 to 

May 2005 in accordance with generally accepted government auditing 

standards.

3

EPA, The Ozone Report: Measuring Progress through 2003 (EPA 454/K-04-001, April 2004); 

and EPA, The Particle Pollution Report: Current Understanding of Air Quality and 

Emissions through 2003 (EPA 454-R-04-002, December 2004). 
Page 30 GAO-05-613 Clean Air Act

Appendix V

Comments from the Environmental 

Protection Agency ApendxiV

Note: GAO comments 

supplementing those in 

the report text appear 

at the end of this 

appendix.
Appendix V

Comments from the Environmental 

Protection Agency

Page 31 GAO-05-613 Clean Air Act
Appendix V

Comments from the Environmental 

Protection Agency

Page 32 GAO-05-613 Clean Air Act
Appendix V

Comments from the Environmental 

Protection Agency

Page 33 GAO-05-613 Clean Air Act
Appendix V

Comments from the Environmental 

Protection Agency

Page 34 GAO-05-613 Clean Air Act

See comment 1.

See comment 2.
Appendix V

Comments from the Environmental 

Protection Agency

Page 35 GAO-05-613 Clean Air Act
Appendix V

Comments from the Environmental 

Protection Agency

Page 36 GAO-05-613 Clean Air Act

See comment 3.

See comment 4.
Appendix V

Comments from the Environmental 

Protection Agency

Page 37 GAO-05-613 Clean Air Act

The following are GAO’s comments on EPA’s letter dated May 18, 2005.

GAO Comments 1. As background, our report states that while air quality in the United 

States has steadily improved over the last few decades, more than a 

hundred million Americans continue to live in communities where 

pollution causes the air to be unhealthy at times, according to EPA. 

EPA has apparently interpreted this statement as implying that missed 

deadlines described in the report are responsible for the scope of the 

current particulate matter and ozone nonattainment problems. 

However, our report does not make that link.

2. EPA provided us several examples of cases in which a delay in the 

implementation of certain specific requirements did not lead to a delay 

in improvements in air quality. While our draft report indicated that 

requirements met late delayed improvements in air quality, we did not 

mean to suggest that all late requirements delayed improvements in air 

quality. Therefore, we revised the report to say that delays in 

implementation of some of the requirements may have led to delays in 

improvements in air quality.

3. During the course of our work, we discussed our proposed 

methodology with EPA officials and they agreed with our plan to use 

the Federal Register publication date as the completion date for 

relevant requirements. In commenting on the draft report, however, the 

agency stated that its Office of Air and Radiation generally considers 

that it has met its statutory obligation to issue a rule on the date on 

which a final rule is signed and disseminated to the public, which is 

likely to be earlier than the publication of that rule in the Federal 

Register. Although we agree with EPA’s assessment that using the 

signature date, rather than the Federal Register publication date, would 

not change the report’s conclusions, we revised the report to include 

EPA’s comment. 

4. We revised report language throughout to reflect the fact that certain 

actions originally included as requirements of Title I of the Clean Air 

Act Amendments of 1990 were established earlier but are related to 

these amendments. 
Page 38 GAO-05-613 Clean Air Act

Appendix VI

GAO Contacts and Staff Acknowledgments ApendxiVI

GAO Contacts John B. Stephenson, (202) 512-3841 (stephensonj@gao.gov)

Christine Fishkin, (202) 512-6895 (fishkinc@gao.gov)

Staff 

Acknowledgments

In addition to the individuals named above, Nancy Crothers, Christine 

Houle, Karen Keegan, Judy Pagano, and Nico Sloss made key contributions 

to this report.

(360543)
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