Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

Congressional research reportOct 23, 2006

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Visibility, Regional Haze, and the Clean Air

Act: Status of Implementation

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Specialist in Energy and Environmental Policy

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Specialist in Environmental Policy

October 23, 2006

Congressional Research Service

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RL32483

CRS Report for Congress

Prepared for Members and Committees of Congress

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 (PM2.5), to which sulfur dioxide (SO2) and nitrogen oxides (NOx) are

important contributors. EGUs are major emitters of SO2 and NOx.

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 the Clean Air Interstate Rule (CAIR) designed 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 model CAIR trading program for EGUs interacts with the BART

requirement for EGUs. In 2005, EPA made a final determination to exempt EGUs subject to the

CAIR trading program from the Section 169A visibility BART program. 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 more cost-effective than direct regulation (such as BART). The Administration has

proposed “Clear Skies” legislation to create a more integrated trading process for addressing SO2

and NOx emissions from EGUs, but it failed to be reported out of committee in the Senate. CAIR

represents a regulatory initiative to achieve a step in coordinating certain CAA programs, but it

may be that a statutory solution will be necessary.

This report will not be updated.

Congressional Research Service

Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

Contents

Background to the Regional Haze Rule .......................................................................................1

The Regional Haze Rule .............................................................................................................3

The Regional Haze Rule and Very Fine Particulates ....................................................................4

The Regional Haze Rule and the Clean Air Interstate Rule ..........................................................6

The Clean Air Interstate Rule (CAIR)....................................................................................6

BART, CAIR, and Electric Generating Units .........................................................................7

Determining BART under the Regional Haze Rule ..........................................................7

Substituting CAIR for BART ..........................................................................................9

EPA’s Justification......................................................................................................... 10

Questions ............................................................................................................................ 11

Implications .............................................................................................................................. 12

Tables

Table 1. Schedule Outline for Section 308 Regional Haze Program .............................................5

Table 2. EPA Estimates of Regional NOx and SO2 Emissions ......................................................6

Contacts

Author Contact Information ...................................................................................................... 13

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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 (SO2), particulates (PM), and nitrogen oxides

(NOx) 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 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

1977 Clean Air Act Amendments, Part C, Title 1. P.L. 95-95.

EPA could administratively set PSD requirements for other pollutants for which National Ambient Air Quality

Standards (NAAQS) have been established.

Section 169A, Clean Air Act, 42 U.S.C. 7492 (italics added).

45 Federal Register 80084 (December 2, 1980); 40 CFR 51.300-51.307.

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

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 lack of initiative on visibility during the 1980s prompted the Congress to revisit the issue 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 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 the region. Based on those data, the commissions were to issue reports

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

Environmental Defense Fund v. Gearstick, No. CO2-6850 (N.D. CA) (April 20, 1984). See 49 Federal Register

20647 (May 16, 1984).

56 Federal Register 50172 (October 3, 1991); 40 CFR 52.

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.”

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.

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

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

only 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 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 I 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 I area within the state or affected by emissions within

The recommendations are summarized in ibid., pp. i-iii.

Ibid., pp. 34-35.

62 Federal Register 41138 (July 31, 1997).

64 Federal Register 35714-35774 (July 1, 1999).

Referring to section 309 of the rule (not of the statute).

A measure of clarity of the air.

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

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 I 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.

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 I areas in Colorado rather than the Section 308 program, up to the year

2018.18 Focused primarily on SO2 emissions, which are a major component of regional haze,

states set voluntary “SO2 milestones,” instead of requiring BART. 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 SO2 reduction milestones out to the year 2018, along with the back-up

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 (PM2.5), which are key

contributors to regional haze. To implement the 1997 PM2.5 NAAQS, a monitoring network had

to be established and three years of data collected before states could identify PM2.5

nonattainment areas and begin the development of 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 PM2.5

attainment. As a result, EPA proposed that states preparing SIPs for attaining the 1997 PM2.5

Defined at Clean Air Act, Section 169A(g)(7).

Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, and Wyoming.

Arizona, New Mexico, Oregon, Utah, and Wyoming.

Recommendations for Improving Western Vistas, Report of the Grand Canyon Visibility Transport Commission to

the United States Environmental Protection Agency, June 10, 1996.

68 Federal Register 33764-33791 (June 5, 2003).

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

NAAQS 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 PM2.5 nonattainment areas.21

This linking of the implementation schedules of regional haze and PM2.5 rules effectively

extended the regional haze actions. Under the nationwide Section 308 program, states classified

as attainment under the 1997 PM2.5 NAAQS have one year after that designation (which occurred

on December 17, 2004) to submit to EPA their revisions to SIPs to implement the regional haze

requirements. But states classified as nonattainment under the 1997 PM2.5 NAAQS will have

three years after that designation to submit to EPA their revised SIP, allowing them to combine

implementation of the regional haze rule with the 1997 PM2.5 NAAQS compliance. 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 PM2.5 compliance. 22

Table 1. Schedule Outline for Section 308 Regional Haze Program

Date

Regulatory Action

April 5, 2005

Effective date of final PM2.5 NAAQS area designations.

April 5, 2006, or one

year after the final PM2.5

designation date

States submit haze plans for areas designated attainment or

unclassifiable under PM2.5 NAAQS.

April 5, 2008

States submit haze plans for areas designated nonattainment

under PM2.5 NAAQS. States participating in regional planning

submit haze plans.

2011-2013 (five years

after approval of haze plans)

Sources subject to BART required to install and

operate BART.

2013 (and every five years

thereafter)

States submit progress report on reasonable progress goals

and adequacy of haze plans.

Before 2018

Sources comply with any emission trading or alternative

control measures.

2018 (and every 10

years thereafter)

States complete revised haze plans.

Source: Environmental Protection Agency.

For discussion of the PM2.5 SIP deadlines, see CRS Report 97-8, Air Quality: Background Analysis of EPA’s 1997

Ozone and Particulate Matter Standards, pp. 22-23 (note 54).

Section 6102(c)(2), The Transportation Equity Act for the 21st Century.

In September 2006, EPA promulgated a revised PM2.5 NAAQS. With an implementation schedule five years later

than the 1997 standard, there maybe some future effort to coordinate the revised standard’s implementation with the

regional haze rule’s schedule.

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

The Regional Haze Rule and the Clean Air

Interstate Rule

The regional haze and PM2.5 programs interact with other air quality programs as well—notably

EPA’s finalized Clean Air Interstate Rule (CAIR).23

The Clean Air Interstate Rule (CAIR)24

Published May 12, 2005, CAIR addresses the effect of interstate transport of air pollutants on

nonattainment of the NAAQS for fine particulates (PM2.5) and the 8-hour ozone standard. For

PM2.5, the rule finds that the interstate transport of SO2 and NOx from 23 states and the District of

Columbia contribute significantly to downwind nonattainment; for ozone, the rule finds that

interstate transport of NOx from 25 states and the District of Columbia contribute significantly to

downwind nonattainment of the 8-hour ozone standard. Both SO2 and NOx are involved in

regional haze and PM2.5, with SO2 playing a particularly major role,25 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, CAIR generally follows (with some important exceptions) the

methodology EPA employed with the NOx SIP Call,26 a regulation addressing regional ozone

nonattainment. With CAIR, EPA proposes a region-wide emissions cap for NOx and SO2 to be

implemented in two phases—2010 (2009 for NOx) and 2015. Based on the methodology

employed in the 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 SO2 Emissions

(million tons)

NOx

Emissions

(no cap)

NOx

Emissions

(with cap)

SO2 Emissions

(no cap)

SO2 Emission

(with cap)

2010 (2009 for NOx)

2.7

1.5

8.7

5.1

2015

2.8

1.3

7.9

4.0

Year

Environmental Protection Agency, Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Clean

Air Interstate Rule); Revisions to Acid Rain Program; Revisions to NOx SIP Call; Final Rule (70 Federal Register

25162-25405, May 12, 2005).

For more on CAIR, see CRS Report RL32927, Clean Air Interstate Rule: Review and Analysis, by (name redacted); also

CRS Report RL32273, Air Quality: EPA’s Proposed Interstate Air Quality Rule, by (name redacted) and (name redacted)

(available from the authors).

SO2 is the subject of numerous provisions of the Clean Air Act: these include the SO2 NAAQS, New Source

Performance Standards (NSPS), Prevention of Significant Deterioration (PSD), Acid Precipitation provisions (Title

IV), and mobile source provisions.

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 (name redacted) and (name redacted) (available

from the authors).

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

Year

NOx

Emissions

(no cap)

NOx

Emissions

(with cap)

SO2 Emissions

(no cap)

SO2 Emission

(with cap)

2020

2.8

1.3

7.7

3.3

Source: Environmental Protection Agency, 2005.

BART, CAIR, and Electric Generating Units

Both the regional haze rule and CAIR address emissions of SO2 and NOx. Although each could

control emissions from any major source of these emissions, 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 SO2 and NOx, electric generating units become a critical point of

interaction between CAIR and the regional haze rule. The contentious issue has been whether

BART for EGUs can be and should be superseded by CAIR for affected EGUs.

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....27

EPA originally proposed guidelines to assist states in determining BART in 2001.28 After portions

of the regional haze rule were remanded by the court in the American Corn Growers v. EPA

decision,29 EPA revised and re-proposed its BART determination guidelines in May 2004.30 In

particular, the proposed revisions focused 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.”31

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 SO2

Clean Air Act, section 169A(4)(b)(2)(A).

66 Federal Register 38108-38135 (July 20, 2001).

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.”

69 Federal Register 25184-25232 (May 5, 2004).

69 Federal Register 25203 (May 5, 2004).

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

reduction requirement at 95% removal or emission limitations in the range of 0.1 to 0.15 lb. SO2

per million Btu. 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.32

On July 6, 2005, EPA finalized its guidelines for determining BART.33 For coal-fired EGUs

greater than 200 Mw, the BACT presumptive emissions limit for SO2 was set at 95% removal or

an emissions rate of 0.15 lb. SO2/mmBtu. NOx BACT presumptive limits for coal-fired EGUs are

based on the coal-type burned and the firing configuration. The limits range from 0.15 lb./mmBtu

NOx for tangential-fired boilers using subbituminous coal to 0.62 lb./mmBtu NOx for wet-bottom

tangential-fired boilers using bituminous coal.34

The 1999 regional haze rule also allowed for a trading program for implementing BART if the

state requesting a trading program submitted analyses 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.”35 Under the 1999 regional haze rule, the specific requirements for substituting emissions

trading for BART were as follows:36

•

“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 I 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.37 The proposed guidelines would have required

dispersion modeling of BART and the trading program to ensure better visibility. Specifically, the

modeling should identify (1) the difference in visibility conditions under both approaches for

69 Federal Register 25199 (May 5, 2004).

Environmental Protection Agency, Regional Haze Regulations and Guidelines for Best Available Retrofit

Technology (BART) Determinations; Final Rule, 70 Federal Register 39103-39172 (July 6, 2005).

70 Federal Register 39172 (July 6, 2005).

64 Federal Register 35768 (July 1, 1999).

66 Federal Register 38108-38135 (July 20, 2001).

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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. 38

These alternative program guidelines were not included in the final rule because of a D.C. Circuit

Court decision vacating EPA’s approval of the WRAP alternative trading program under Section

309 of the regional haze rule (the WRAP Annex Rule).39 Instead, on July 20, 2005, the EPA

proposed new requirements for an emissions trading program that responded to the objections

raised by the court. The final rule was published on October 13, 2006.40 With respect to the

alternative trading program, the primary change to the existing guidelines was to bring the

program requirement into compliance with the American Corn Growers v. EPA decision. 41

Specifically, the revision permits states to use the same BART determination approach to develop

a baseline estimate of BART in the alternative program, as it allows for source-by-source BART.

As stated by EPA:

In short, to demonstrate that a trading program or other alternative program makes greater

reasonable program than BART, the State can develop an estimate of BART emissions

reductions using the same approach that it would use to establish source-by-source BART

emission limitations under the BART guidelines.42

Substituting CAIR for BART

CAIR is designed to assist states in meeting the PM2.5 and 8-hour ozone NAAQS by mitigating

interstate air pollution. As a preferred implementation strategy, EPA encourages 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 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.43

EPA opened the issue of substituting CAIR for BART in a supplemental proposed rule published

June 10, 2004, that detailed the proposed CAIR model trading program.44 Among its provisions,

the proposed supplemental rule would have permitted 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 proposed to amend the trading program requirements under the regional

haze rule. The proposed supplemental rule would have amended and revised the regional haze

69 Federal Register 25184-25232 (May 5, 2004).

Center for Energy and Economic Development v. EPA (398 F. 3d 653, 2005).

71 Federal Register 60612-60634 (October 13, 2006).

American Corn Growers Association v. EPA, 291 F. 3d 1 (May 24, 2002, D.C. Cir.).

71 Federal Register 60612-60634 (October 13, 2006), p. 60615.

Although, unlike the NOx SIP Call, CAIR focuses solely on electric generating units, where the NOx SIP Call

included other sources of cost-effective NOx reductions.

69 Federal Register 32683-32772 (June 10, 2004).

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

regulation to exempt electric utility sources that comply with the CAIR from the regional haze

regulation’s BART requirement. Specifically, the CAIR would have:45

•

Revised Section 308(e)(2) so that sources participating in the CAIR trading

program would have been 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.”

•

Inserted a renumbered Section 308(e)(3) providing that a state’s BART-eligible

electric generating units that participate in the CAIR trading program would not

have to install and operate BART.

Thus, the proposed supplemental CAIR revisions to the regional haze rule would have done

two things: (1) exempted 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) exempted such

sources from BART.

In the final CAIR, EPA decided to defer the decision on substituting CAIR for BART for affected

units until the BART guidelines are finalized. As stated by EPA:

The results clearly indicate that the CAIR will achieve greater reasonable progress than

BART as proposed, measured by the proposed better-than-BART test. At this time, we can

foresee no circumstances under which BART for EGUs could produce greater visibility

improvement than the CAIR. However, for the reasons noted in section IX.C.1 above, we are

deferring a final determination of whether the CAIR makes greater reasonable progress than

BART until the BART guidelines for EGUs and the criteria for BART-alternative programs

are finalized.46

In the final BART rule, EPA finalized its determination that CAIR achieves greater progress than

BART and may be used by states as a BART substitute.47 In making this determination, EPA notes

that “we are not constraining the discretion of States to determine which sources are subject to

BART and to make BART determinations. CAIR-affected States are not required to accept our

determination that CAIR may substitute for BART.”48

EPA’s Justification

The 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:

69 Federal Register 32738 (June 10, 2004).

Clean Air Interstate Rule, p. 25304.

70 Federal Register 39137 (July 6, 2005).

70 Federal Register 39143 (July 6, 2005).

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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.49

Analysis to support this declaration was provided in the June 2004 proposal supplemental rule for

the CAIR trading program, and in the final CAIR.50 The Bush Administration uses a regional

analysis of the visibility improvement resulting from BART and CAIR to justify exempting

BART-eligible electric generating units from BART and from the requirement that trading rather

than installing BART must yield greater reasonable progress. The two-part test examined the

effects of the two programs on 116 class I areas with respect to potential visibility degradation.

The analysis concludes that “CAIR emissions reductions in the East produce significantly greater

visibility improvements than source-specific BART.”51 On a nationwide basis, EPA states:

... the visibility modeling shows that for all 116 class I areas evaluated, the average visibility

improvement, on the 20 percent worst days, in 2015 was 0.5 dv [deciview] under the CAIR

cap-and-trade program in the East and BART in the West, but only 0.2 dv under the

nationwide source-specific BART approach.52

Questions

This linking of 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 I area—not an average of all 156 class I

areas or the 116 (29 in the East) class I areas EPA analyzed for its CAIR

determination. EPA cites data limitations for not including other class I areas (5

in the East) in its analysis.53 With the final BART determination guidelines

permitting 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 SO2 emissions from a future 2015

baseline envisioned 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

69 Federal Register 25204 (May 5, 2004).

70 Federal Register 25299-25304 (May 12, 2005).

70 Federal Register 25303 (May 12, 2005).

69 Federal Register 32705, note 34 (June 10, 2004).

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

old (1962) that may reasonably be anticipated to cause or contribute to any

impairment of visibility in any class I area. CAIR’s model trading program is a

regional scheme focused on all EGUs that are greater than 25Mw within the 23

state PM2.5 region.54

•

Achieving visibility goals. As noted above, using an analysis that grafted the

CAIR trading program onto an individual BART program for the other 25 BARTeligible 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 EGUs such as required under 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.55

From a policy standpoint, EPA has presented the Clean Air Interstate Rule—and the

accompanying Mercury (Hg) rule—as a “suite of integrated air actions” to reduce emissions of

three pollutants: SO2, NOx, and Hg. By promulgating guidelines to help states determine

appropriate state emissions budgets for their trading program and to exempt sources subject to the

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 provisions

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 oxides 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 legislated that the initial implementation schedules of the SIP process for the 1997

PM2.5 NAAQS and the SIP process for the regional haze rule be coordinated.

Now EPA is linking the two programs by determining that certain CAIR program provisions can

in effect substitute for related but different visibility requirements. Whether it can do this while

69 Federal Register 32709 (June 10, 2004).

For data on air quality trends, see EPA’s website at http://www.epa.gov/airtrends/.

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Visibility, Regional Haze, and the Clean Air Act: Status of Implementation

accomplishing the express purposes and requirements of both Section 109 and Section169A is

subject to debate and possible litigation. By using a 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.”56 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 marketoriented 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.57 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 SO2, NOx, and Hg.

Implemented through a tradable allowance program, the emission caps would generally be

imposed in two phases: 2008 and 2018. Although different in geographic scope, the

Administration’s Clean Air Interstate Rule and mercury rule 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 regulatory approach.

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. 58 EPA’s

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.

Author Contact Information

(name redacted)

Specialist in Energy and Environmental Policy

[redacted]@crs.loc.gov, 7-....

(name redacted)

Specialist in Environmental Policy

[redacted]@crs.loc.gov, 7-....

Felicity Barringer, “Critics Say Clean-Air Plan May Be a Set Back for Parks,” New York Times, May 31, 2004.

See CRS Report RL32755, Air Quality: Multi-Pollutant Legislation in the 109th Congress, by (name redacted) and (name

redacted).

In the 109th Congress, S. 131, introduced by Senator Inhofe, is modeled on the Administration’s Clear Skies

proposal. However, after committee markup, the Senate Environment and Public Works Committee failed to report S.

131 to the floor on a 9-9 tied vote (March 9, 2005). See CRS Report RL33552, Clean Air Act Issues in the 109th

Congress, by (name redacted).

Congressional Research Service

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