Order Code RL32483
CRS Report for Congress
Received through the CRS Web
Visibility, Regional Haze, and the Clean Air Act:
Status of Implementation
July 22, 2004
Larry Parker
Specialist in Energy Policy
Resources, Science, and Industry Division
John Blodgett
Deputy Assistant Director
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

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Visibility, Regional Haze, and the Clean Air Act:
Status of Implementation
Summary
Section 169A of the Clean Air Act (CAA) sets “as a national goal the prevention
of any future, and the remedying of any existing, impairment to visibility” in
designated “class I areas” (e.g., national parks and wilderness areas). It requires 26
categories of major stationary sources of pollution — including electric generating
units (EGUs) — in existence on the date of enactment (1977), but not more than 15
years old as of that date, to install “best available retrofit technology” (BART) if the
state determines the source may reasonably be anticipated to cause or contribute to
any impairment of visibility in any class I area. A key contributor to regional haze
is very fine particles (PM ), to which sulfur dioxide (SO ) and nitrogen oxides
2.5
2
(NOx) are important contributors. EGUs are major emitters of SO and NOx.
2
The Environmental Protection Agency (EPA) was directed to issue regulations
to assure that State Implementation Plans (SIPs) required (1) reasonable progress
toward meeting the national goal and (2) compliance with specific provisions,
including the BART requirements. However, EPA delayed issuing regional haze
rules, and in 1990 Congress amended the CAA’s visibility requirements. EPA issued
the final regional haze rule on July 1, 1999. Among its provisions, the rule required
“reasonable progress” toward visibility improvement and a state BART
implementation plan. For BART, states could alternatively propose a trading
program — but only if it achieved greater progress in improving visibility.
The BART requirement’s interaction with other air pollution control programs
has become an issue — most notably its relation to a proposed Clean Air Interstate
Rule (CAIR) to reduce emissions crossing state lines and hindering compliance with
National Ambient Air Quality Standards (NAAQS). CAIR involves controls on SO2
and NOx, focuses on EGUs as the most cost-effective source to control, and proposes
using a trading mechanism to accomplish reductions. At issue is how the CAIR
trading program for EGUs interacts with the BART requirement for EGUs. In 2004
EPA proposed to exempt EGUs subject to the CAIR trading program from the
Section 169A visibility BART program. EPA justified this through an analysis that
looked at class I areas collectively rather than individually. Critics of EPA’s proposal
point out that Section 169A specifies protection of individual class I areas and that
BART requirements would be more stringent than CAIR for individual sources; and
they claim that overall, visibility improvements attributable to CAIR would not be
adequate to meet CAA goals.
EPA’s effort to meld the visibility program with CAIR is consistent with its
expressed desire to redirect CAA compliance strategies toward a market-oriented,
cap-and-trade program, viewed by many as a more cost-effective approach to
pollution control than direct regulation (such as BART). The Administration has
proposed “Clear Skies” legislation to create a more integrated trading process for
addressing SO and NOx emissions from EGUs, but Congress has yet to act. EPA’s
2
proposal represents a regulatory initiative to achieve a partial step in coordinating
certain CAA programs, but it may be that a statutory solution will be necessary. This
report will be updated as events warrant.

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Contents
Background to the Regional Haze Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The Regional Haze Rule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The Regional Haze Rule and Very Fine Particulates . . . . . . . . . . . . . . . . . . . 5
The Regional Haze Rule and the Interstate Air Quality Rule . . . . . . . . . . . . 6
The Proposed Clean Air Interstate Rule (CAIR) . . . . . . . . . . . . . . . . . . 6
BART, CAIR, and Electric Generating Units . . . . . . . . . . . . . . . . . . . . 7
Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
List of Tables
Table 1. Schedule Outline for Section 308 Regional Haze Program . . . . . . . . . . . 6
Table 2. EPA Estimates of Regional NOx and SO Caps . . . . . . . . . . . . . . . . . . . 7
2

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Visibility, Regional Haze, and the
Clean Air Act: Status of Implementation
Background to the Regional Haze Rule
When amending the Clean Air Act in 1977, Congress added provisions focused
on protecting the quality of clean air areas, and especially of national parks and other
important national sites.
Codifying regulations developed by EPA in 1974 and 1975, the Prevention of
Significant Deterioration (PSD) program focuses on preventing further deterioration
of air quality in pristine areas of the country by specifying how much increase in
pollution levels is permitted.1 Mandatory class I areas — those areas that receive the
maximum amount of protection — include most national parks, national wilderness
areas, and national memorial parks, currently 156 areas. PSD regulations apply to
emissions of sulfur dioxide, particulates, and nitrogen oxides from new and modified
sources of air pollution.2
Along with the PSD program for new sources, the Congress also added a new
Section 169A, setting “as a national goal the prevention of any future, and the
remedying of any existing, impairment to visibility in mandatory class I Federal
areas....”3 PSD and Section 169A act in tandem, with PSD controlling new sources
of impairment and Section 169A reducing emissions from existing sources of
impairment. Under PSD, major new or modified sources in PSD areas must undergo
preconstruction review and must install “best available control technology” (BACT);
more stringent controls can be required if modeling indicates that BACT is
insufficient to avoid violating an allowable PSD increment or the National Ambient
Air Quality Standard itself. Under Section 169A, 26 categories of major stationary
sources of pollution in existence on the date of enactment (1977), but not more than
15 years old as of that date, must install “best available retrofit technology” (BART)
if the state determines the source may reasonably be anticipated to cause or contribute
to any impairment of visibility in a class I area. Included in the list are electric
generating units (EGUs).
Implementing these provisions protecting visibility has not been easy,
particularly Section 169A respecting existing sources. First, EPA had to define what
visibility was. In general, visibility impairment from human activities manifests
itself in two ways: (1) plume blight, where a clearly identifiable plume of smoke
1 1977 Clean Air Act Amendments, Part C, Title 1. P.L. 95-95.
2 EPA could administratively set PSD requirements for other pollutants for which National
Ambient Air Quality Standards (NAAQS) have been established.
3 Section 169A, Clean Air Act, 42 U.S.C. 7492 (italics added).

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CRS-2
emanates from one or more sources; and (2) regional haze, where a uniform
reduction in visual range occurs, or a layered discoloration by hovering bands of air
tinged brown, yellow, or red. Second, EPA had to promulgate regulations within 24
months of enactment to assure that State Implementation Plans (SIPs) required (1)
reasonable progress toward meeting the national goal mentioned earlier, and (2)
compliance with several very specific provisions, including the Best Available
Retrofit Technology (BART) requirements for existing sources.
EPA promulgated rules in 1980 to address visibility impairment that was
“reasonably attributable” to a single source or small group of sources — i.e., plume
blight.4 As with many air pollution regulations, these visibility regulations are
implemented by states through SIPs. In general, the 36 states with mandatory class
I areas were required to revise their SIPs to assure reasonable progress toward the
national visibility goal. The major elements of the regulation were (1) identifying
existing sources causing visibility impairment and creating procedures for
determining which existing stationary sources should be subject to BART
requirements; (2) assessing potential adverse impacts from proposed new sources (or
modified old sources) and recommending remedial actions via the New Source
Review (NSR) process and the PSD program; (3) developing a 10-15 year long-term
strategy to make “reasonable progress” toward the visibility goal; and (4) conducting
visibility monitoring in mandatory class I areas.
As noted, these regulations deal with plume blight only — regional haze
reduction was explicitly delayed until some future date. This lack of aggressive
implementation of Section 169A extended to the implementation of the 1980
regulations as well. After 35 of 36 states missed the September 1981 deadline for
final visibility plans, the Environmental Defense Fund sued the EPA in 1982 to
implement the plume blight regulations. The suit was settled in 1984 with the EPA
developing a phased-in schedule for compliance with a December 1986 deadline for
states to revise their SIPs to include controls on existing sources that hinder visibility
goals.5 This sequential implementation of plume blight regulations actually extended
through 1989. So far, the only BART installation to occur under the 1980 regulations
has been the installation of sulfur dioxide scrubbers at the Navajo Generating Station
in Arizona in 1991.6
EPA’s inaction during the 1980s prompted the Congress to act on visibility in
the 1990 amendments to the Clean Air Act. Those actions included a new Title IV,
controlling precursors of acid rain and regional haze,7 and a new Section 169B. In
some ways, Section 169B was a triggering mechanism to force EPA to move on
Section 169A with respect to regional haze. Specifically, the 1990 Amendments
4 45 Federal Register 80084 (December 2, 1980); 40 CFR 51.300-51.307.
5 Environmental Defense Fund v. Gearstick, No. CO2-6850 (N.D. CA) (April 20, 1984). See
49 Federal Register 20647 (May 16, 1984).
6 56 Federal Register 50172 (October 3, 1991); 40 CFR 52.
7 As noted by Section 401(a)(1): “the presence of acidic compounds and their precursors in
the atmosphere and in deposition from the atmosphere represents a threat to natural
resources, ecosystems, materials, visibility, and public health.”

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CRS-3
required EPA to establish a Grand Canyon Visibility Transport Commission
(GCVTC) within 12 months of enactment (and other commissions upon its own
discretion or petition from at least two states). Commissions were required to assess
the scientific, technical, and other data available on visibility impairment from
potential or projected emissions growth in their region. Based on those data, the
commissions were to issue a report within four years to EPA recommending what
measures, if any, should be taken to remedy such impairment. Within 18 months of
receiving a commission’s report, EPA was to carry out its responsibilities under
Section 169A, including criteria for measuring “reasonable progress” toward the
national goal. Finally, states affected by any regulations promulgated under Section
169A were required to revise their SIPs within 12 months of such promulgation.

In 1991, a Visibility Transport Commission for the region affecting visibility in
Grand Canyon National Park was established. In June 1996, this commission
(consisting of the governors of Arizona, California, Colorado, Nevada, New Mexico,
Oregon, Utah, and Wyoming, and the leaders of five Indian tribes) approved a set of
recommendations for improving western vistas.8 There were nine primary
recommendations, including increased energy conservation, use of renewable energy,
and emission reductions from stationary sources.9 The commission’s Baseline
Forecast anticipated that current regulatory programs would reduce emissions of
sulfur dioxide from stationary sources (power plants, smelters, and other industrial
sources) 13% by the year 2000, although additional measures under consideration
might reduce emissions 20%-30%. In light of this uncertainty about the effects of
current programs and the fact that emissions were projected to decline in the short
term without additional regulation, the commission agreed to set regional targets for
sulfur dioxide emissions in the year 2000. The ultimate targets would be in the range
of 50%-70% reduction by the year 2040, but “interim targets may also be needed to
ensure steady and continuing emission reductions and to promote investment in
pollution prevention.”10 If the targets are exceeded, this would trigger a regulatory
program, probably including a regional cap on emissions, with market-based trading.
The Regional Haze Rule
The 1990 Clean Air Act Amendments required the EPA Administrator to take
action under Section 169A within 18 months of receipt of a commission report. The
proposed rule appeared in the Federal Register on July 31, 1997.11
The final regional haze rule was published on July 1, 1999.12 The regional haze
program represents a nationwide effort to protect 156 PSD class I areas from
8 Recommendations for Improving Western Vistas, Report of the Grand Canyon Visibility
Transport Commission to the United States Environmental Protection Agency, June 10,
1996. A ninth state, Idaho, was included in the region, but chose not to participate in the
commission.
9 The recommendations are summarized in ibid., pp. i-iii.
10 Ibid., pp. 34-35.
11 62 Federal Register 41138 (July 31, 1997).
12 64 Federal Register 35714-35774 (July 1, 1999)

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CRS-4
visibility impairment from manmade air pollution. All 50 states are included under
the program — including those that do not have any class I areas within their
boundaries — since pollution causing haze can travel beyond a state’s boundaries
and contribute to impaired visibility in a class I area located elsewhere. The rule
encourages regional approaches. Indeed, the final rule includes special provisions
(Section 309 program)13 that permit the former member-states of the Grand Canyon
Visibility Transport Commission to implement their specific recommendations
within the framework of the national regional haze program (Section 308 program).
States are required under Section 169A to develop SIPs that ensure reasonable
progress toward the national goal. Under Section 308 of the rule, SIPs must contain
the following:
! Reasonable progress goals. States must establish goals expressed
in deciviews14 that provide for reasonable progress toward achieving
natural visibility conditions in class 1 areas by 2064.
! Calculations of baseline and natural visibility conditions. States
must determine baseline conditions expressed in deciviews for the
most impaired and least impaired days during 2000-2004.
! Long-term planning. States must submit a long-term strategy to
address regional haze for each class 1 area within the state or
affected by emissions within the state. The strategy must include
compliance schedules, enforceable emission limitations, and other
measures necessary to achieve reasonable progress goals.
! Monitor strategy. States must submit with the SIP a strategy for
measuring, characterizing, and reporting regional haze.
! Best Available Retrofit Technology (BART). States must submit
a BART implementation plan, including emission limitations and
compliance schedules for each BART-eligible source15 that “may
reasonably be anticipated” to contribute to visibility impairment in
a class 1 area. States may choose to use a trading program or other
alternative, if that alternative will achieve greater reasonable
progress to natural visibility conditions than BART.
! Tracking Progress. SIPs must include several provisions to ensure
the adequacy of the SIP. In particular, the SIP must include
requirements for submitting SIP revisions to EPA every 10 years,
beginning in 2018. Progress reports tracking the state’s reasonable
progress efforts are due every five years. Reports must include a
determination of the adequacy of the state’s SIP.
13 Referring to section 309 of the rule (not of the statute).
14 A measure of clarity of the air.
15 Defined at Clean Air Act, Section 169A(g)(7).

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CRS-5
An alternative program is provided in Section 309 as an option for nine former
members of the Grand Canyon Visibility Transport Commission (GCVTC).16 Five
states chose to meet the EPA deadline for inclusion under this option.17 Based on the
commission’s 1996 report, Section 309 allows states to choose to follow the
commission’s recommendations for reducing visibility impairment in the 16 class 1
areas in Colorado rather than the Section 308 program, up to the year 2018.18
Focused primarily on sulfur dioxide (SO ) emissions, which are a major component
2
of regional haze, states set voluntary “SO milestones,” instead of requiring BART.
2
If the milestones are not achieved, then a back-up mandatory emissions trading
program would be activated to ensure compliance with the milestones. The successor
organization to the GCVTC, the Western Regional Air Partnership (WRAP)
submitted to EPA an annex to the commission’s report in 2000 that identifies the
voluntary SO reduction milestones out to the year 2018, along with the back-up
2
trading program details. The 2018 milestone of 510,000 tons would represent a
reduction of 320,000 tons from 1990 emissions of 830,000 tons. EPA approved the
annex in 2003.19
The Regional Haze Rule and Very Fine Particulates
While working on the regional haze rule, EPA was also proposing to implement
a new National Ambient Air Quality Standard (NAAQS) for very fine particulates
(PM ), which are key contributors to regional haze. To implement the PM
2.5
2.5
NAAQS, a monitoring network had to be established and three years of data collected
before states could identify PM nonattainment areas and begin the development of
2.5
SIPs. Adhering to the separate schedules could lead some states to revising SIPs
twice, once for visibility and then, a year or two later, for PM attainment. As a
2.5
result, EPA proposed that states preparing SIPs for attaining the PM NAAQS
2.5
combine it and their submittal of the regional haze SIP revisions.20 In P.L. 105-178,
enacted June 9, 1998, Congress codified this proposal and also extended deadlines
for areas not designated nonattainment. The enacted language stipulates that SIPs
implementing the regional haze rule be submitted on the same schedule as those for
PM nonattainment areas.21
2.5
This linking of the implementation schedules of regional haze and PM rules
2.5
effectively extended the regional haze actions. Under the nationwide Section 308
program, states classified as attainment under the PM NAAQS will have one year
2.5
after that designation (estimated to occur in late 2004-early 2005) to submit to EPA
16 Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming.
17 Arizona, New Mexico, Oregon, Utah, and Wyoming.
18 Recommendations for Improving Western Vistas, Report of the Grand Canyon Visibility
Transport Commission to the United States Environmental Protection Agency, June 10,
1996.
19 68 Federal Register 33764-33791 (June 5, 2003)
20 For discussion of the PM SIP deadlines, see CRS Report 97-8, Air Quality: Background
2.5
Analysis of EPA’s 1997 Ozone and Particulate Matter Standards, pp. 22-23 (note 54).
21 Section 6102(c)(2), The Transportation Equity Act for the 21st Century.

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CRS-6
their revisions to SIPs to implement the regional haze requirements. But states
classified as nonattainment under the PM NAAQS will have three years after that
2.5
designation to submit to EPA their revised SIP, allowing them to combine
implementation of the regional haze rule with the PM NAAQS compliance.
2.5
Optional SIP schedules are provided for states that chose to develop a regional,
coordinated approach to regional haze. Likewise, states choosing to follow the
recommendations of the GCVTC have an alternative compliance schedule. Table 1
provides a rough implementation schedule for the regional haze rule based on EPA’s
latest estimated schedule for PM compliance.
2.5
Table 1. Schedule Outline for
Section 308 Regional Haze Program
Date
Regulatory Action
December 31, 2004
Anticipated: EPA promulgates final PM NAAQS
2.5
area designations.
December 31, 2005, or one year
States submit haze plans for areas designated
after the final PM designation
attainment or unclassifiable under PM NAAQS.
2.5
2.5
date
December 31, 2007, or three
States submit haze plans for areas designated
years after the final PM
nonattainment under PM NAAQS. States
2.5
2.5
designation date, but no later
participating in regional planning submit haze
than December 31, 2008
plans.
2011-2013 (five years after
Sources subject to BART required to install and
approval of haze plans)
operate BART.
2013 (and every five years
States submit progress report on reasonable
thereafter)
progress goals and adequacy of haze plans.
Before 2018
Sources comply with any emission trading or
alternative control measures.
2018 (and every 10 years
States complete revised haze plans.
thereafter)
Source: Environmental Protection Agency.
The Regional Haze Rule and the
Interstate Air Quality Rule
The regional haze and PM programs interact with other air quality programs
2.5
as well — notably EPA’s proposed Interstate Air Quality Rule (now called the Clean
Air Interstate Rule or CAIR).
The Proposed Clean Air Interstate Rule (CAIR). Published January 30,
2004, the proposed rule addresses the effect of interstate transport of air pollutants
on nonattainment of the NAAQS for fine particulates (PM ) and the 8-hour ozone
2.5

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CRS-7
standard.22 For PM , the proposed rule finds that the interstate transport of sulfur
2.5
dioxide (SO ) and nitrogen oxides (NOx) from 28 states and the District of Columbia
2
contribute significantly to downwind nonattainment; for ozone, the proposed rule
finds that interstate transport of NOx from 25 states and the District of Columbia
contribute significantly to downwind nonattainment of the 8-hour standard. Both
SO and NOx are involved in regional haze and PM , with SO playing a particularly
2
2.5
2
major role,23 so all three programs ultimately deal with some of the same sources of
pollution — of which electric generating units are a major one.
To remedy the situation, the proposed rule generally follows the methodology
EPA employed with the NOx SIP Call,24 a regulation addressing regional ozone
nonattainment. With CAIR, EPA proposes a region-wide emissions cap for NOx and
SO to be implemented in two phases — 2010 and 2015. Based on the methodology
2
employed in the proposed rule, EPA’s estimates of emissions under the caps are
provided in Table 2. EPA determined the caps by applying “highly cost effective”
pollution controls on electric generating units.
Table 2. EPA Estimates of Regional NOx and SO Caps
2
(million tons)
NOx
NOx
SO2
SO Emission
Year
Emissions
Emissions
Emissions
2
(cap)
(no cap)
(cap)
(no cap)
2010
3.1
1.6
9.0
3.9
2015
3.2
1.3
8.3
2.7
Source: Proposed Interstate Air Quality Rule (69 Federal Register 4566-4650).
BART, CAIR, and Electric Generating Units. Both the regional haze rule
and proposed CAIR would control emissions of SO and NOx. Although each could
2
control emissions from any major source of these emissions, the proposed CAIR is
focused on electric generating units, while the regional haze rule is focused on 26
different categories of sources. Therefore, as major sources of SO and NOx, electric
2
generating units become a critical point of interaction between CAIR and the regional
haze rule. The contentious issue is whether BART for EGUs can be and should be
superseded by CAIR for affected EGUs.
22 Environmental Protection Agency, Rule to Reduce Interstate Transport of Fine
Particulate Matter and Ozone (Interstate Air Quality Rule); Proposed Rule. 69 Federal
Register 4566-4650 (January 30, 2004).
23 SO is the subject of numerous provisions of the Clean Air Act: these include the SO
2
2
NAAQS, New Source Performance Standards (NSPS), Prevention of Significant
Deterioration (PSD), Acid Precipitation provisions (Title IV), and mobile source provisions.
24 For background and discussion of the NOx SIP Call, see CRS Report 98-236 ENR, Air
Quality: EPA’s Ozone Transport Rule, OTAG, and Section 126 Petitions — A Hazy
Situation? by Larry Parker and John Blodgett.

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CRS-8
Determining BART under the Regional Haze Rule. The Clean Air Act
explicitly states that BART decisions are to be made according to their impact on
visibility. As stated in Section 169A:
...each major stationary source ... which, as determined by the State ... emits any
air pollutant which may reasonably be anticipated to cause or contribute to any
impairment of visibility in any such area, shall procure, install, and operate, as
expeditiously as practicable (and maintain thereafter) the best available retrofit
technology, as determined by the State ... for controlling emissions from such
source for the purpose of eliminating or reducing any such impairment....25
EPA originally proposed guidelines to assist states in determining BART in
2001.26 After portions of the regional haze rule were remanded by the court in the
American Corn Growers v. EPA decision,27 EPA revised and re-proposed its BART
determination guidelines in May 2004.28 In particular, the proposed revisions focus
on state determinations of individual source contributions, rather than on the
collective contribution to visibility impairment as contained in the proposed regional
haze rule and 2001 guidelines: “... this reproposal focuses on the use of single source
emission modeling for assessing the degree of improvement in visibility from various
BART control levels.”29
Under Section 169A, BART is a plant-by-plant determination made by the state
— except for EGUs over 750 Mw in capacity, for which EPA makes the
determination. When EPA proposed its May 2004 revisions to the regional haze rule,
it proposed to set the default 750 Mw EGU SO reduction requirement at 95%
2
removal or emission limitations in the range of 0.1 to 0.15 lb. SO per million Btu.
2
For units between 250 Mw and 750 Mw, EPA proposed a rebuttable presumption
that states should require the same limitations. As stated by EPA:
This presumption would apply unless the State has persuasive evidence that an
alternative determination is justified. Our intent is that it should be extrememly
[sic] difficult to justify a BART determination less than the default control level
for a plant greater than 750 Mw, and just slightly less difficult for a plant 750
Mw or smaller.30

At the same time, the 1999 regional haze rule allows for a trading program for
implementing BART if the state requesting a trading program submits analyses
25 Clean Air Act, section 169A(4)(b)(2)(A).
26 66 Federal Register 38108-38135 (July 20, 2001).
27 American Corn Growers Association v. EPA, 291 F. 3d 1 (May 24, 2002, D.C. Cir.). In
that case, the court ruled that it is the states, not EPA, who must determine which BART-
eligible sources should be subject to BART. Further, the court stated that the regional haze
rule tied the states’ hands and forced them to require BART controls at sources “without any
empirical evidence of the particular source’s contribution to visibility impairment in a Class
I area.”
28 69 Federal Register 25184-25232 (May 5, 2004).
29 69 Federal Register 25203 (May 5, 2004).
30 69 Federal Register 25199 (May 5, 2004).

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CRS-9
demonstrating “that the emissions trading program or other alternative measure will
achieve greater reasonable progress than would have resulted from the installation
and operation of BART at all sources subject to BART in the State.”31 Under the
current regional haze rule, the specific requirements for substituting emissions
trading for BART are as follows:32
! “The State must demonstrate that this emission trading program ...
will achieve greater reasonable progress than would be achieved
through the installation and operation of BART.” This
demonstration must be based on analysis of the visibility
improvement that would be achieved in class 1 areas.
! The trading program must apply to all BART-eligible sources unless
the source has an enforceable emission limitation that the EPA and
state determines meets BART.
! Emission reductions must occur by 2018 (the first long-term strategy
period).
! “A demonstration that the emission reductions resulting from the
emission trading program ... will be surplus to those reductions
resulting from measures adopted to meet requirements of the CAA
as of the baseline date of the SIP.”
The proposed 2001 BART guidelines also proposed guidelines for states to
assist them in determining the appropriate state emission budgets (or caps) for their
trading program to ensure it met the greater reasonable progress requirement.33 The
proposed guidelines would have required dispersion modeling of BART and the
trading program to ensure better visibility. Specifically, the modeling should identify
(1) difference in visibility conditions under both approaches for each class I area; and
(2) the average difference in visibility over all class I areas affected by the region’s
emissions. The analysis would demonstrate greater reasonable progress if (1)
visibility does not decline in any class I area; and (2) there is overall improvement
in visibility as determined by comparing the average differences over all affected
class I areas. These trading program guidelines were re-proposed on May 5, 2004,
essentially unchanged.34
Substituting CAIR for BART. CAIR is designed to assist states in meeting
the PM NAAQS by mitigating interstate air pollution. As a preferred
2.5
implementation strategy, EPA would encourage states to use a trading program to
reduce emissions in a cost-effective manner. To set allocations, EPA compared the
costs of various control strategies to determine the most cost-efficient allocation
scheme. That cost analysis indicated that electric generating units were the most
31 64 Federal Register 35768 (July 1, 1999).
32 64 Federal Register 35768 (July 1, 1999).
33 66 Federal Register 38108-38135 (July 20, 2001).
34 69 Federal Register 25184-25232 (May 5, 2004).

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CRS-10
cost-effective source of emission reductions. Thus, like the NOx SIP Call before it,
the emissions allocations under the CAIR proposed trading program are based on
cost-effectiveness criteria.
Details about this proposed trading program for CAIR were provided by EPA
in a supplemental proposed rule published June 10, 2004.35 Among its provisions, the
proposed rule would permit electric generating units to use the emission trading
program under CAIR to meet the BART requirement imposed by the regional haze
rule. To achieve this, EPA proposes to amend the trading program requirements
under the regional haze rule. The proposed CAIR would amend and revise the
regional haze regulation to exempt electric utility sources that comply with the CAIR
from the regional haze regulation’s BART requirement. Specifically, the CAIR
would:36
! Revise Section 308(e)(2) so that sources participating in the CAIR
trading program would be excluded from the requirement that a state
demonstrate that its regional haze emission trading program “will
achieve greater reasonable progress than would be achieved through
the installation and operation of BART.”
! Insert a renumbered Section 308(e)(3) providing that a state’s
BART-eligible electric generating units that participate in the CAIR
trading program do not have to install and operate BART.
Thus, the proposed supplemental CAIR revisions to the regional haze rule
would do two things: (1) exempt states from having to demonstrate that sources
complying with the CAIR through its proposed trading program would achieve
greater reasonable progress than would be achieved through the installation and
operation of BART; and (2) exempt such sources from BART.
EPA’s Justification. This proposal by EPA to declare CAIR to be better than
BART for individual BART-eligible electric generating units had been strongly
hinted in its May 2004 proposed revisions to BART guidelines. In that proposal,
EPA included a strong statement of support for both employing trading programs to
address regional haze, and the use of CAIR as a “better than BART” alternative. As
stated by EPA:
Based on our current evaluation, we believe the [Interstate Air Quality Rule, later
CAIR] ... as proposed, is clearly better than BART for those affected EGUs in
the affected States which we propose to cover under the IAQR. We thus expect
that the final IAQR would satisfy the BART requirements for affected EGUs that
are covered pursuant to the final IAQR.37
Analysis to support this declaration is provided in the June 2004 proposal
supplemental rule for the CAIR trading program. The Bush Administration justifies
35 69 Federal Register 32683-32772 (June 10, 2004).
36 69 Federal Register 32738 (June 10, 2004).
37 69 Federal Register 25204 (May 5, 2004).

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exempting BART-eligible electric generating units from BART and from the
requirement that trading rather than installing BART must yield greater reasonable
progress through a regional analysis of the visibility improvement resulting from
BART and CAIR. The two-part test examined the effects of the two programs on 44
class I areas with respect to potential visibility degradation, and 15 class I areas with
respect to average visibility. The analysis concludes that on a national basis, “the
proposed CAIR cap-and-trade program is better than BART for BART eligible EGUs
within the proposed CAIR region.”38 As stated by EPA:
... on a national basis, the visibility modeling shows that for the 44 class I areas
evaluated, the average visibility improvement, on the 20 percent worst day, in
2015 was 0.7 dv [deciview] under the proposed CAIR cap-and-trade programs,
but only 0.4 dv under the source-specific BART approach.39
Questions. This attempt to link the CAIR to the regional haze rule is based
on the programs’ common characteristic of controlling sulfur dioxide and nitrogen
oxides. EPA use of a proposed collective methodology designed to assist states in
determining state emission budgets to justify excluding individual units from
undergoing individual state-led BART review has proven contentious. Questions
include the following:
! Visibility impacts on Class I Areas individually and collectively.
Critics contend that EPA’s analysis suggesting that “nationwide” the
“average” visibility would improve more under a CAIR/BART
program than a BART program is inadequate. They observe that
Section 169A discusses BART in terms of visibility impairment of
“any” class 1 area — not an average of all 156 class 1 areas or the 44
class I areas EPA analyzed for its CAIR determination. EPA cites
data limitations for using only 44 of the 110 monitoring sites in its
analysis.40 If EPA finalizes its proposed May 2004 BART
determination guidelines to permit such an analysis, litigation is
likely.
! Stringency of BART versus CAIR. On an individual EGU basis,
the 95% reduction requirement contained in EPA’s BART
guidelines is substantially more stringent than the overall 67%
reduction in SO emissions from a future 2015 baseline envisioned
2
in CAIR. However, the scope of the two scenarios is different. For
EGUs, BART is required nationwide on powerplants over 250
million Btu (thermal input basis) operating in 1977 but not more
than 15 years old (1962) that may reasonably be anticipated to cause
or contribute to any impairment of visibility in any class I area.
38 69 Federal Register 32706 (June 10, 2004).
39 69 Federal Register 32706 (June 10, 2004).
40 69 Federal Register 32705, note 34 (June 10, 2004).

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CAIR’s proposed trading program is a regional scheme focused on
all EGUs within the 28 state region that are greater than 25Mw.41
! Achieving visibility goals. As noted above, using an analysis that
grafted the CAIR trading program onto an individual BART
program for the other 25 BART-eligible categories, EPA argues that
CAIR is better than BART. Opponents argue that the analysis is
insufficient — that a 1-2 deciview improvement will not achieve the
CAA visibility goal. Instead, opponents assert that a 7-9 deciview
improvement is necessary to achieve the CAA’s visibility goal of
preventing any future, and remedying any existing, visibility
impairment in class I areas. Achieving such a goal will require
BART controls on the level of EPA’s proposed default levels, plus
controls on additional EGU such as proposed by CAIR.
Implications
The Clean Air Act has evolved over time in response to a developing
understanding of the environment, new technologies, and changes in the nation’s
transportation, energy, and industrial sectors. The result has been a patchwork of
requirements that are not always consistent — and may even be incompatible — at
any given moment. Moreover, implementing regulations change and are added to
over time. Although the evolution of the act has resulted in a structure that some
consider unwieldy, emissions of most air pollutants have substantially declined, and
the number of persons living in areas where pollution exceeds standards has
diminished.42
From a policy standpoint, EPA has presented the proposed Clean Air Interstate
Rule — and the accompanying proposed Mercury (Hg) rule — as a “suite of
integrated air actions” to reduce emissions of three pollutants: SO , NOx, and Hg. By
2
proposing guidelines to help states determine appropriate state emissions budgets for
their trading program and to exempt sources subject to the proposed CAIR from the
individual BART determinations required by Section 169A (visibility impairment),
EPA appears to be trying to extend the “suite” to the visibility protection provision
of the CAA. In other words, EPA is endeavoring to transform CAIR from another
layer on the already multilayered cake called the Clean Air Act to an integrative
program that simplifies the layers.
As discussed, this effort to meld Section 169A (visibility) and Section 109
(NAAQS) implementation strategies based on their common characteristic of
controlling sulfur dioxide and nitrogen oxide raises numerous issues. In the Clean
Air Act, their only procedural link is the SIP process, but they have different scopes,
purposes, and requirements. Because of the happenstance that the timing of the PM2.5
NAAQS and the regional haze rules partly coincided, EPA proposed and Congress
41 69 Federal Register 32709 (June 10, 2004).
42 For data on air quality trends, see EPA’s website at [http://www.epa.gov/airtrends/].

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legislated that the initial implementation schedules of the SIP process for the 1997
PM NAAQS and the SIP process for the regional haze rule be coordinated.
2.5
Now EPA is attempting to link the two programs by proposing through
rulemaking that certain CAIR program provisions can in effect substitute for related
but different visibility requirements. Whether it can do this while accomplishing the
express purposes and requirements of both Section 109 and Section169A is subject
to debate. By using a proposed collective analysis designed to assist states in
determining state emission budgets to justify excluding individual units from
undergoing individual state-led BART review, EPA concludes that the CAIR
program adequately meets visibility requirements — a conclusion that is contentious.
Indeed, opponents of the attempt have described it as regulatory “bait and switch.”43
This conflict is not surprising as EPA is attempting to integrate regulatory provisions
that are separate in many essential respects.
It appears the Administration’s goal is to redirect CAA compliance strategies
toward a market-oriented cap-and-trade program — viewed by many observers as a
more cost-effective approach to pollution control than direct regulation (such as the
BART program). Such a redirection of compliance approaches has been proposed
— and the Title IV acid rain provisions of the CAA are often cited as the preeminent
example of its application. Several proposals have focused on electric generating
units.44 One approach is a “multi-pollutant” strategy — a framework based on a
consistent set of emissions caps, implemented through emissions trading. In
February 2002, the Bush Administration announced a “Clear Skies” multi-pollutant
proposal that would amend the Clean Air Act to place emission caps on electric
utility emissions of SO , NOx, and Hg. Implemented through a tradable allowance
2
program, the emission caps would generally be imposed in two phases: 2008 and
2018. Although different in geographic scope, the Administration’s proposed Clean
Air Interstate and Mercury rules are very similar in terms of reduction requirements
as Clear Skies. However, unlike EPA’s “suite of integrated air action,” Clear Skies
contains significant conforming language to avoid conflicts with other CAA
provisions such as Section 169A. The Administration has stated its preference for
Clear Skies over its proposed regulations.
However, the Congress has yet to move any multi-pollutant proposal to the
floor, nor has it given EPA broad authority to reconstitute regulatory approaches into
market-oriented ones. EPA’s proposed combining of CAIR and BART represents
a regulatory initiative to achieve at least a partial step in coordinating regulatory
programs under a market-oriented approach. It is possible, however, that a statutory
solution could be necessary.
43 Felicity Barringer, “Critics Say Clean-Air Plan May Be a Set Back for Parks,” New York
Times, May 31, 2004.
44 See CRS Report RL31779, Air Quality: Multi-Pollutant Legislation in the 108th Congress,
byLarry Parker.

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