Clean Air Issues in the 112th Congress

January 4, 2011 – December 31, 2012 R41563

Clean Air Issues in the 112th Congress
Updated December 31, 2012
Congressional Research Service
https://crsreports.congress.gov
R41563

Clean Air Issues in the 112th Congress

Summary
Air quality has improved substantially in the United States in the 40 years of EPA’s Clean Air Act
regulation, but more needs to be done, according to the agency’s science advisers, to protect
public health and the environment from the effects of air pollution. Thus, the agency continues to
promulgate regulations addressing air pollution using authority given it by Congress more than 20
years ago. In the 112th Congress, Members from both parties raised questions about the cost-
effectiveness of some of these regulations and/or whether the agency has exceeded its regulatory
authority in promulgating them. Others in Congress have supported EPA, noting that the Clean
Air Act, often affirmed in court decisions, authorized or required the agency’s actions.
EPA’s regulatory actions on greenhouse gas (GHG) emissions were one focus of congressional
interest. Although the Obama Administration consistently said that it would prefer that Congress
pass new legislation to address climate change, such legislation was not considered in the 112th
Congress. Instead, EPA developed GHG regulations using its existing Clean Air Act authority.
EPA finalized GHG emission standards for cars and light trucks on April 1, 2010, and August 28,
2012, and for larger trucks on August 9, 2011. The implementation of these standards, in turn,
triggered permitting and Best Available Control Technology requirements for new major
stationary sources of GHGs.
It was the triggering of standards for stationary sources (power plants, manufacturing facilities,
etc.) that raised the most concern in the 112th Congress: legislation was considered in both the
House and Senate aimed at preventing EPA from implementing these requirements. In the first
session of the 112th Congress, the House passed H.R. 1, which contained provisions prohibiting
the use of appropriated funds to implement various EPA GHG regulatory activities, and H.R. 910,
a bill that would have repealed EPA’s endangerment finding, redefined “air pollutants” to exclude
greenhouse gases, and prohibited EPA from promulgating any regulation to address climate
change. In the Senate, H.R. 1 was defeated, and an amendment identical to H.R. 910 (S.Amdt.
183) failed on a vote of 50-50.
EPA took action on a number of other air pollutant regulations, generally in response to court
actions remanding previous rules. Remanded rules included the Clean Air Interstate Rule (CAIR)
and the Clean Air Mercury Rule—rules designed to control the long-range transport of sulfur
dioxide, nitrogen oxides, and mercury from power plants through cap-and-trade programs. Other
remanded rules included hazardous air pollutant (“MACT”) standards for boilers and cement
kilns. EPA addressed the court remands through new regulations that have now been
promulgated. Many in Congress viewed the new regulations as overly stringent. The House
passed four bills (H.R. 2250, H.R. 2401, H.R. 2681, and H.R. 3409) to delay or revoke the new
standards and change the statutory requirements for their replacements.
In addition to the power plant and MACT rules, EPA also reviewed ambient air quality standards
(NAAQS) for ozone, particulates, and other widespread air pollutants. These standards serve as
EPA’s definition of clean air, and drive a range of regulatory controls. The revised NAAQS also
faced opposition in the 112th Congress. As passed by the House, H.R. 2401 and H.R. 3409 would
have amended the Clean Air Act to require EPA to consider feasibility and cost in setting
NAAQS, and H.R. 1633 would have prevented EPA from setting standards for ambient
concentrations of rural dust.
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Introduction
In the 112th Congress, interest in air quality issues was dominated by efforts to prevent the
Environmental Protection Agency (EPA) from promulgating and implementing new emission
control requirements. Often under court order, EPA has used the authorities Congress gave it in
the Clean Air Act of 1970 and subsequent amendments in 1977 and 1990 to address longstanding
issues posed by emissions from mobile sources, electric utilities, and a wide range of industrial
sources.
One focus of congressional interest was EPA regulatory action to limit greenhouse gas (GHG)
emissions1 using existing Clean Air Act authority. Members from both sides of the aisle,
including a majority of the House, expressed concern that EPA was proceeding with GHG
regulations that could have major economic impacts, without direct congressional authorization,
and/or that EPA should delay taking such action until Congress specifically authorizes it.
The Administration countered that it would prefer for Congress to pass new legislation to control
greenhouse gas emissions, but the Clean Air Act already requires action: a 2007 Supreme Court
decision interpreting EPA’s Clean Air Act authority found that the agency must weigh whether
GHG emissions endanger public health and welfare and, if it concludes that they do, proceed with
regulation.2
The 111th Congress struggled to produce its own approach to climate change. In June 2009, the
House narrowly passed H.R. 2454, a 1,428-page bill addressing a number of interrelated energy
and climate change issues. Among its numerous provisions, the bill would have established cap-
and-trade programs for GHG emissions, beginning in 2012. The Senate did not act, however: two
Senate committees reported bills,3 but the prospect of obtaining 60 votes for either bill appeared
slim, and neither came to the floor. In the 112th Congress, the focus was not on comprehensive
legislation to address GHG emissions, but on legislation to prevent EPA from taking action on the
issue. The result was the same, however: the House passed legislation; the Senate did not.
Issues related to emissions from electric power plants—principally sulfur dioxide (SO2), nitrogen
oxides (NOx), and mercury—were another focus of interest in the 112th Congress. Regulations
addressing these emissions were vacated by the D.C. Circuit Court of Appeals in 2008.4 EPA
developed new regulations to address the court’s concerns, finalizing regulations to address SO2
and NOx on July 6, 2011,5 and mercury and other air toxics on December 21, 2011.6 Congress

1 Six greenhouse gases, or groups of gases, are addressed by EPA regulatory actions: carbon dioxide (CO2), methane
(CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). Of
these, carbon dioxide, produced by combustion of fossil fuels, is by far the most prevalent, accounting for 85% of
annual emissions of the combined group when measured as CO2 equivalents.
2 Massachusetts v. EPA, 549 U.S. 497 (2007).
3 The Environment and Public Works Committee reported S. 1733, and the Energy and Natural Resources Committee
reported S. 1462.
4 North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008) addressed the sulfur dioxide and nitrogen oxides regulations,
and New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008) addressed the mercury regulations.
5 The final rule appeared in the Federal Register August 8, 2011. See U.S. Environmental Protection Agency, “Federal
Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone and Correction of SIP Approvals,” 76
Federal Register 48208, August 8, 2011. Explanatory material can be found at http://www.epa.gov/crossstaterule/
actions.html. The rule is generally referred to as the Cross-State Air Pollution Rule.
6 The final rule appeared in the Federal Register February 16, 2012, at 77 Federal Register 9304, and explanatory
materials are available at http://www.epa.gov/airquality/powerplanttoxics/actions.html.
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conducted numerous oversight hearings and considered legislation to overturn EPA’s regulations.
In this case, too, House-passed legislation died in the Senate.
The Obama Administration’s EPA also reviewed several Bush Administration and earlier
decisions regarding national ambient air quality standards (NAAQS), as it is required to do by
Section 109 of the Clean Air Act. NAAQS represent EPA’s formal judgment regarding how clean
the air must be to protect public health and welfare; the standards set in motion monitoring and
planning requirements, which in turn lead to designation of “nonattainment areas” and the
imposition of emission controls.
 On January 19, 2010, the agency proposed a more stringent NAAQS for ozone,
having concluded that a 2008 revision to the standard did not satisfy the
requirements of the Clean Air Act. As proposed, the NAAQS was projected to
have both costs and benefits in the tens of billions of dollars. Amid heavy
lobbying on both sides of the issue, EPA sent a final decision to the Office of
Management and Budget for interagency review in July 2011. At the President’s
request, EPA withdrew the decision on September 2, 2011, and resumed
implementation of the 2008 standard.
 On June 22, 2010, the agency promulgated revisions to the NAAQS for SO2; 59
counties would violate the new SO2 standard, based on the most recent
monitoring data available at the time.7 None violated the old standard.
 The agency also completed reviews of the NAAQS for four other pollutants,
notably particulate matter (PM), which is emitted by a wide range of mobile and
stationary sources. A revised PM standard was promulgated in December 2012,
including a more stringent fine particulate (PM2.5) standard.
Congress paid close attention to the EPA reviews and, again, the House passed bills that were not
acted on by the Senate.
This report provides a brief overview of the climate change, power plant, and air quality standard
issues, as well as information on other Clean Air Act issues that the 112th Congress addressed.
More detailed information on most of the issues can be found in other CRS reports, which are
referenced throughout this report.
EPA’s Greenhouse Gas Regulations
EPA’s actions to regulate GHG emissions stem from more than a decade of petitions and
litigation. Responding to a 1999 petition that it regulate greenhouse gases from new motor
vehicles, the agency in 2003 denied that it had such authority, arguing that GHGs did not fall
within the Clean Air Act’s definition of “air pollutants.” The denial was challenged by
Massachusetts, 11 other states, and various other petitioners in a case that ultimately reached the
Supreme Court. In an April 2, 2007 decision (Massachusetts v. EPA), the Court found by 5-4 that
EPA does have authority to regulate greenhouse gas emissions, since the emissions are clearly air
pollutants under the Clean Air Act’s definition of that term.8 The Court’s majority concluded that

7 EPA noted that the number of counties that would be formally designated nonattainment would likely be different
from the 59 EPA identified, for two reasons. First, EPA promulgated changes to the monitoring requirements along
with the new standard. Second, the actual designations would most likely be made based on 2009-2011 monitoring
data, whereas the 59 counties were identified using 2007-2009 data.
8 Massachusetts v. EPA, 549 U.S. 497 (2007). The majority held: “The Clean Air Act’s sweeping definition of ‘air
pollutant’ includes ‘any air pollution agent or combination of such agents, including any physical, chemical ...
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EPA must, therefore, decide whether emissions of these pollutants from new motor vehicles
contribute to air pollution that may reasonably be anticipated to endanger public health or
welfare, or provide a reasonable explanation why it cannot or will not make that decision, such as
that there is insufficient information to make the decision. If it makes an “endangerment finding,”
the act requires the agency to establish standards for emissions of the pollutants.
On December 15, 2009, acting in response to the Court’s decision, EPA finalized an
endangerment finding for greenhouse gas emissions from motor vehicles, under Section 202(a) of
the act.9 Relying on this finding, EPA finalized GHG emission standards for new cars and light
trucks, April 1, 2010.10 The implementation of these standards has, in turn, triggered permitting
requirements and the imposition of Best Available Control Technology for new major stationary
sources of GHGs beginning January 2, 2011. (For information on these regulations and permit
requirements, see CRS Report R40506, Cars, Trucks, and Climate: EPA Regulation of
Greenhouse Gases from Mobile Sources, and CRS Report R41212, EPA Regulation of
Greenhouse Gases: Congressional Responses and Options.)
The prospect of GHG standards for motor vehicles, which affect cars and light trucks beginning
in model year 2012, has not been particularly controversial. On May 19, 2009, President Obama
announced an agreement involving nine U.S. and foreign auto manufacturers; the federal
government; the governors of California, Michigan, and Massachusetts; the United Auto Workers;
and environmental groups under which EPA and the National Highway Traffic Safety
Administration (NHTSA) would proceed with a joint rulemaking in which GHG emissions from
new motor vehicles would be reduced under the Clean Air Act, while NHTSA would set
corresponding fuel economy standards under the Corporate Average Fuel Economy (CAFE)
program.11 The objective of the new greenhouse gas standards is to reach reduction levels similar
to those adopted by the state of California and 13 other states, who will harmonize their standards
with those of EPA as part of the agreement. The California standards required about a 30%
reduction in GHG emissions from new vehicles by 2016. The auto industry supported the national
agreement, in part, to avoid having to meet standards on a state-by-state basis; thus, it has not
supported efforts to block EPA’s motor vehicle GHG standards.
On July 29, 2011, the President announced a similar agreement with 13 U.S. and foreign auto
manufacturers under which harmonized GHG and fuel economy standards would be set for model
years 2017-2025. This second round of standard development has led to regulations requiring a

substance or matter which is emitted into or otherwise enters the ambient air.... ‘ ... Carbon dioxide, methane, nitrous
oxide, and hydrofluorocarbons are without a doubt ‘physical [and] chemical ... substances[s] which [are] emitted into ...
the ambient air.’ The statute is unambiguous.” For additional discussion, see CRS Report RS22665, The Supreme
Court’s Climate Change Decision: Massachusetts v. EPA, by Robert Meltz.
9 74 Federal Register 66496. While generally referred to as the “endangerment finding” (singular), the Federal
Register notice consists of two separate findings: a Finding that Emissions of Greenhouse Gases Endanger Public
Health and Welfare, and a Finding that Greenhouse Gases From Motor Vehicles Cause or Contribute to the
Endangerment of Public Health and Welfare.
10 The standards appeared in the Federal Register May 7, 2010 at 75 Federal Register 25324. For additional
information, including a link to the standards, see http://www.epa.gov/otaq/climate/regulations.htm#finalR.
11 The President’s announcement and related documents, including a Notice of Upcoming Joint Rulemaking to
Establish Vehicle GHG Emissions and CAFE Standards, which appeared in the May 22, 2009 Federal Register, and
both the draft and final emission standards can be found at http://www.epa.gov/otaq/climate/regulations.htm. For
additional information, see CRS Report R40166, Automobile and Light Truck Fuel Economy: The CAFE Standards, by
Brent D. Yacobucci; or CRS Report R40506, Cars, Trucks, and Climate: EPA Regulation of Greenhouse Gases from
Mobile Sources, by James E. McCarthy and Brent D. Yacobucci.
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further reduction of about 35% in GHG emissions by 2025, with projected fleetwide fuel
economy of 54.5 miles per gallon. The standards were finalized August 28, 2012.12
EPA has also promulgated GHG emission standards for medium- and heavy-duty trucks. EPA’s
endangerment finding specifically referenced medium- and heavy-duty trucks as among the
sources that contribute to the GHG emissions for which it found endangerment. In addition, the
National Highway Traffic Safety Administration (NHTSA) was required by Section 102 of the
Energy Independence and Security Act of 2007 (EISA, P.L. 110-140) to promulgate fuel economy
standards for medium- and heavy-duty trucks, reflecting the “maximum feasible improvement” in
fuel efficiency. Thus, on August 9, 2011, EPA and NHTSA finalized integrated GHG emission
standards and fuel economy standards for medium- and heavy-duty vehicles.13 The standards will
be phased in between 2014 and 2018. When fully implemented, they will require an average per
vehicle reduction in GHG emissions of 17% for diesel trucks and 12% for gasoline-powered
trucks.
In addition to the motor vehicle GHG standards, EPA has received petitions asking the agency to
regulate GHGs from a variety of other sources, including coal mines, concentrated animal feeding
operations (CAFOs), aircraft, ocean-going ships, nonroad engines and equipment (e.g.,
construction equipment, farm equipment, recreational equipment, forklifts, harbor craft, and lawn
and garden equipment), and fuels. Another petition asks the agency to set National Ambient Air
Quality Standards for seven specific greenhouse gases. The agency has also faced lawsuits
seeking to force it to regulate GHGs from a variety of sources, including power plants, petroleum
refineries, nonroad vehicles and engines, and the Portland cement industry.
The decisions to move forward on GHG standards for new motor vehicles have been seen by
many as precedents for these other potential standards,14 and, indeed, EPA has begun to move
forward on GHG standards for a broader set of emission sources. On December 23, 2010, the
agency announced that it had reached a settlement agreement with 11 states, the City of New
York, the District of Columbia, and 3 environmental groups under which it would propose GHG
emission standards for power plants by July 26, 2011, and for refineries by December 10, 2011,
with promulgation by May 2012 and November 2012 respectively. The power plant deadline was
later extended, and proposed regulations (for new units only) were released March 27, 2012. The
agency did not propose guidelines for existing units, and it is unclear when it will do so. The
agency also missed the December 2011 deadline for proposal of refinery standards; it is unclear
when these regulations will be proposed.
Even without EPA decisions on these petitions or the proposal of standards for specific industries,
the adoption of GHG standards for motor vehicles has triggered GHG permit requirements for
new stationary sources, as a result of language in Section 165 of the act. That section requires
preconstruction permits and the imposition of best available control technology for new major
sources of all pollutants “subject to regulation” under the act. The permit requirements began to
take effect January 2, 2011. It is this triggering of standards for stationary sources (power plants,
manufacturing facilities, and others) that appears to have raised the most concern in Congress:

12 http://www.epa.gov/otaq/climate/regs-light-duty.htm#new1.
13 The standards appeared in the September 15, 2011, Federal Register. U.S. Environmental Protection Agency, U.S.
Department of Transportation, “Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and
Heavy-Duty Engines and Vehicles; Final Rules,” 76 Federal Register 57106.
14 For a further discussion of these issues, see CRS Report R40984, Legal Consequences of EPA’s Endangerment
Finding for New Motor Vehicle Greenhouse Gas Emissions, by Robert Meltz, CRS Report R40506, Cars, Trucks, and
Climate: EPA Regulation of Greenhouse Gases from Mobile Sources, by James E. McCarthy and Brent D. Yacobucci,
and archived CRS Report R40585, Climate Change: Potential Regulation of Stationary Greenhouse Gas Sources
Under the Clean Air Act, by Larry Parker and James E. McCarthy.
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legislation has been considered in both the House and Senate aimed at preventing EPA from
implementing these requirements.
Legislation on Climate Change
In the 112th Congress, introduced legislation took several forms. The broadest legislation (such as
Representative Upton’s and Senator Inhofe’s H.R. 910/S. 482) would have repealed EPA’s
endangerment finding, redefined “air pollutants” to exclude greenhouse gases, prohibited EPA
from promulgating any regulation to address climate change, and prohibited EPA from granting
the state of California future waivers allowing it to control GHG emissions from mobile
sources.15 H.R. 910 passed the House April 7, 2011, 255-172. A Senate amendment identical to
H.R. 910 (S.Amdt. 183) failed on a vote of 50-50, April 6, 2011. The provisions of H.R. 910 were
passed again by the House as Title II of H.R. 3409, September 21, 2012.
Some of the other bills or amendments introduced in the 112th Congress would have:
 suspended EPA actions regulating stationary source emissions of GHGs for two
years (Senator Rockefeller’s S. 231 and Representative Capito’s H.R. 199).
Senator Rockefeller’s bill, introduced as S.Amdt. 215 to S. 493, a bill dealing
with small business innovation, failed on a vote of 12-88, April 6, 2011;16
 enacted EPA’s Tailoring Rule into statutory law (Senator Baucus’s S.Amdt. 236).
Senator Baucus’s amendment failed on a vote of 7-93, April 6, 2011;
 amended the Clean Air Act to provide that greenhouse gases are not subject to the
act (Representative Blackburn’s H.R. 97);
 prohibited EPA from using funds to implement or enforce cap-and-trade
programs or other requirements pertaining to stationary sources of GHG
emissions (Representative Poe’s H.R. 153);
 prohibited any federal agency, in carrying out any act or program to reduce the
effects of greenhouse gas emissions on climate change, from imposing a fee or
tax on gaseous emissions emitted directly by livestock (Representative
Fortenberry’s H.R. 279); or
 prohibited U.S. regulation of carbon dioxide until China, India, and Russia
implement similar reductions (Senator Vitter’s S. 15).
Meanwhile, EPA itself promulgated regulations and guidance that delayed the applicability of
requirements for stationary sources of GHGs until 2011 and focused its initial permitting efforts
on the largest emitters, granting smaller sources at least a six-year reprieve.17
Although stand-alone legislation to restrict EPA’s authority has received a great deal of attention,
restricting the agency’s authority to use funds to take specific GHG regulatory actions through

15 Senator Barrasso’s S. 228 and Representative Walberg’s H.R. 750 were similar to the Upton/Inhofe bill in many
respects, including listing a dozen EPA regulatory actions that would be repealed. In addition, the Barrasso/Walberg
bill would have prevented citizens from using common law or civil tort (including nuisance) to seek liability, money
damages, or injunctive relief arising from any potential or actual contribution of a greenhouse gas to climate change.
16 Another amendment that would have provided a two-year moratorium, Senator Stabenow’s and Senator Sherrod
Brown’s S.Amdt. 277, also failed, by a vote of 7-93.
17 The two rules that have these effects are: “Prevention of Significant Deterioration and Title V Greenhouse Gas
Tailoring Rule,” final rule, 75 Federal Register 31514, June 3, 2010; and “Reconsideration of Interpretation of
Regulations that Determine Pollutants Covered by Clean Air Act Permitting Programs,” final rule, 75 Federal Register
17004, April 2, 2010.
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riders on the EPA appropriation seems the more likely avenue by which Congress might limit
EPA action. The overall appropriation bill to which it would be attached might contain other
elements that would make it more difficult to veto. This approach was discussed at some length as
early as 2009, when Senator Murkowski introduced (but ultimately did not offer) an amendment
to the FY2010 Interior, Environment, and Related Agencies Appropriation Act (S.Amdt. 2530). It
came forward in several forms in the 112th Congress.
In FY2011, appropriations for EPA and the rest of the government were provided by a series of
continuing resolutions. In the House, in February 2011, language similar to H.R. 153 was added
to the Full-Year Continuing Appropriations Act, 2011 bill (H.R. 1) during floor debate, on a 249-
177 vote (H.Amdt. 101). H.R. 153, and H.R. 1 as amended, would have prohibited EPA funding
for implementing or enforcing a greenhouse gas cap-and-trade program or any other greenhouse
gas regulatory requirement on stationary sources issued or effective after January 1, 2011
(including the permitting requirements that took effect January 2). However, the Senate failed to
pass the bill, 44-56, March 9, 2011. The final FY2011 budget agreement (H.R. 1473) did not
include restrictions on EPA’s greenhouse gas regulatory authority.
Both the FY2012 and FY2013 EPA appropriations bills (H.R. 2584 and H.R. 6091, as reported by
the House Appropriations Committee) contained major restrictions on EPA’s GHG regulatory
authorities, but the provisions were not enacted.
 The FY2012 bill came to the House floor under an open rule during the last week
of July, 2011, and about 200 amendments were filed for consideration. Action on
the bill was suspended July 28, with more than 150 amendments still pending.
EPA’s FY2012 appropriation ultimately was included in a consolidated
appropriations act, P.L. 112-74, which contained no new restrictions.
 The FY2013 appropriation met a similar fate. It was among the funding measures
included in a six-month continuing resolution that House and Senate leaders
agreed to consider in September 2012. The resolution (P.L. 112-175) did not
include policy provisions such as major new restrictions on EPA’s GHG
regulatory authority.
(For a more detailed discussion of EPA’s regulatory actions and potential congressional
responses, see CRS Report R41212, EPA Regulation of Greenhouse Gases: Congressional
Responses and Options. For information on EPA Appropriations, see CRS Report R41896,
Interior, Environment, and Related Agencies: FY2012 Appropriations, and CRS Report R42520,
Environmental Protection Agency (EPA): Appropriations for FY2013.)
Emissions from Power Plants
In addition to climate change, other clean air issues with a shorter time horizon are being
addressed by EPA and have been the subject of congressional action. Many of these have to do
with emissions from electric power plants.
Coal-fired power plants are among the largest sources of air pollution in the United States. Under
the Clean Air Act, however, they have not necessarily been subject to stringent requirements:
emissions and the required control equipment can vary depending on the location of the plant,
when it was constructed, whether it has undergone major modifications, the specific type of fuel
it burns, and, to some extent, the vagaries of EPA enforcement policies. More than half a dozen
separate Clean Air Act programs could potentially be used to control emissions, which makes
compliance strategy complicated for utilities and difficult for regulators. Because the cost of the
most stringent available controls, for the entire industry, could range into the tens of billions of
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dollars, power companies have fought hard and rather successfully to limit or delay regulations
affecting them, particularly with respect to plants constructed before the Clean Air Act of 1970
was passed.
As a result, emissions from power plants have not been reduced as much as those from some
other sources. Many plants built in the 1950s and 1960s (generally referred to as “grandfathered”
plants) have little emission control equipment.
Collectively, power plants are large sources of pollution. In 2005, they accounted for 10.2 million
tons of sulfur dioxide (SO2) emissions (70% of the U.S. total), 53 tons of mercury emissions
(50% of the U.S. total), and 3.6 million tons of nitrogen oxides (19% of the U.S. total). Power
plants are also considered major sources of fine particles (PM2.5), many of which form in the
atmosphere from emissions from a wide range of stationary and mobile sources. In addition,
power plants account for about 40% of U.S. anthropogenic emissions of the greenhouse gas
carbon dioxide.
With new ambient air quality standards for ozone, fine particles, and SO2 taking effect, emissions
of NOx and SO2 will necessarily have to be reduced to meet standards.18 (These standards are
discussed below under “Air Quality Standards.”) For more than a decade, mercury emissions
have also been a focus of concern. Mercury emitted by power plants and other sources is
deposited in water bodies and is taken up through the food chain: all 50 states have issued fish
consumption advisories due to mercury pollution, covering 16.8 million acres of lakes, 1.25
million river miles, and the coastal waters of 20 entire states.19 A continuing controversy over the
interpretation of New Source Review requirements for existing power plants (which require the
installation of Best Available Control Technology whenever an existing power plant undergoes
major modifications) has exerted pressure for a more predictable regulatory structure, as well.
Thus, some in industry, environmental groups, Congress, and the last three Administrations have
said that legislation addressing power plant pollution in a comprehensive (multi-pollutant)
fashion would be desirable. Such legislation could address the major pollutants on a coordinated
schedule and could rely, to a large extent, on a system such as the one used in the acid rain
program, where national or regional caps on emissions are implemented through a system of
tradable allowances. Despite this broad support in principle, for a variety of reasons,
comprehensive multi-pollutant legislation has gone nowhere. Bills were routinely introduced
beginning in the late 1990s, but none made it to the House or Senate floor. The lack of
congressional action left it to EPA, beginning in the Bush Administration, to fashion emission
standards for power plants, using existing Clean Air Act authority.
Cross-State Air Pollution/Clean Air Interstate Rule (CAIR)
On March 10, 2005, the agency announced that it would promulgate regulations similar to those
in its multi-pollutant bill (the Clear Skies bill) for utility emissions of SO2 and NOx in 28 eastern
states and the District of Columbia.20 These regulations, the Clean Air Interstate Rule (CAIR),

18 NOx contributes to the formation of ozone and fine particles; SO2, besides being a regulated pollutant in its own
right, is among the sources of fine particles.
19 See U.S. EPA, “National Listing of Fish Advisories: Technical Fact Sheet,” September 2009, at http://water.epa.gov/
scitech/swguidance/fishshellfish/fishadvisories/tech2008.cfm#synopsis.
20 The rule appeared in the Federal Register two months later. See U.S. EPA, “Ambient air quality standards,
national—Fine particulate matter and ozone; interstate transport control measures,” 70 Federal Register 25162, May
12, 2005.
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established cap-and-trade provisions for the two pollutants.21 CAIR covered only the eastern half
of the country, but since most of the grandfathered generation capacity is located in the East and
South, EPA projected that nationwide emissions of SO2 would decline 53% by 2015 and NOx
emissions 56%.22 The agency also projected that the rule would result in $85-$100 billion in
health benefits annually by 2015, including the annual prevention of 17,000 premature deaths.
CAIR’s health and environmental benefits would be more than 25 times greater than its costs,
according to EPA.
North Carolina v. EPA
CAIR was one of the few Bush Administration environmental initiatives that was generally
supported by environmentalists. It also had broad support in the regulated community. But a
variety of petitioners, including the state of North Carolina, which argued that the rule was not
strong enough to address pollution from upwind sources, and some individual utilities that felt
they were unfairly treated by the rule’s emission budgets, challenged the rule in the D.C. Circuit,
and the court vacated it July 11, 2008. A unanimous court found that although EPA had
established a “significant contribution” made by power plants to nonattainment of standards and
failure to maintain standards in downwind states, as required by Section 110 of the Clean Air Act,
the agency’s methodology for establishing emission budgets for each state was unrelated to the
state’s contribution to the nonattainment and maintenance problems in specific downwind
states.23 The court also found that the choice of 2015 for a second phase compliance deadline,
based on technological and economic feasibility, ignored EPA’s statutory mandate. It found the
fuel adjustment factors in the rule (which set more stringent requirements for natural gas- and oil-
fired plants than for coal-fired ones) to be arbitrary and capricious. It concluded: “CAIR’s flaws
are deep. No amount of tinkering ... will transform CAIR, as written, into an acceptable rule.”24
Despite the seemingly high hurdle set by the language the court used, EPA, environmental
groups, and the utility and mining industries asked the court to review its decision. On December
23, 2008, the court modified its decision, allowing CAIR to remain in effect until a new rule is
promulgated by EPA.25 The court was not specific about how long this process would be allowed
to take, but stated:
Though we do not impose a particular schedule by which EPA must alter CAIR, we remind
EPA that we do not intend to grant an indefinite stay of the effectiveness of this court’s
decision. Our opinion revealed CAIR’s fundamental flaws, which EPA must still remedy.26
Although they differ on the details of what they support, states, electric utilities, and
environmental groups have all supported a replacement that is similar to CAIR in many respects.
Without CAIR, most eastern states would have huge gaps in their emission control programs,
which would have to be filled by other regulatory measures if the states are to attain the NAAQS
by the statutory deadlines. For the utilities, CAIR was designed to build on the existing regulatory

21 A separate regulation, the Clean Air Mercury Rule (CAMR), promulgated at the same time, established a Clear-
Skies-like cap-and-trade system for mercury emissions. It is described in a separate section below.
22 As compared to nationwide emissions from electric generating units in 2001. Some of the projected reduction would
be due to pre-existing regulations. See U.S. EPA, Office of Air and Radiation, Regulatory Impact Analysis for the Final
Clean Air Interstate Rule, March 2005, pp. 3-3 and 3-4, at http://www.epa.gov/cair/pdfs/finaltech08.pdf.
23 North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008).
24 Id. at 930.
25 North Carolina v. EPA, 550 F.3d 1176 (D.C. Cir. 2008).
26 Ibid.
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framework of cap-and-trade programs under the acid rain program and the “NOx SIP Call.”27
Anticipating the ability to bank and trade emission allowances under CAIR, numerous utilities
had already installed equipment to meet or exceed CAIR’s requirements, the first phase of which
have now been implemented. Environmental groups have argued for a stronger version of
CAIR—particularly its second phase, to be implemented in 2015—but they generally support the
basic approach.
The CAIR Phase 1 rules already appear to be having substantial effects. In 2010, EPA reported,
SO2 emissions from fossil-fueled power plants in the lower 48 states (at 5.1 million tons) were
49% below 2005 levels. NOx emissions from the same sources declined to 2.1 million tons in
2010, 42% less than in 2005.28
EPA’s CAIR Replacement: The Cross-State Air Pollution Rule
On July 6, 2011, EPA finalized a replacement for CAIR, the Cross-State Air Pollution Rule.29 The
Cross-State rule would leave the CAIR Phase 1 limits in place and would have established a
second and third phase of reductions in 2012 and 2014, with particular emphasis on SO2—
emissions of which would decline to 2.4 million tons in the covered states (73% below 2005
levels) in 2014. The rule would cover 28 Eastern, Midwestern, and Southern states and the
District of Columbia. It is a modified cap-and-trade rule. It would allow unlimited trading of
allowances within individual states. Interstate trading would be allowed so long as a state remains
within 18%-21% of its emissions caps. Limiting interstate trading is intended to address the D.C.
Circuit’s ruling, which found CAIR’s unlimited interstate allowance trading program unlawful.
In order to insure that the rule would be implemented quickly, EPA promulgated a Federal
Implementation Plan (FIP) for each of the states: the FIPs specified emission budgets for each
state based on controlling emissions from electric power plants. States would be free to develop
their own State Implementation Plans and may choose to control other types of sources if they
wish, but the federal plan would take effect until the state acts to replace it.
EPA estimates that the Cross-State rule will cost the power sector $2.4 billion annually in 2014,
but it expects the benefits to be 50 to 120 times as great—an estimated $120 billion to $280
billion annually. The most important benefit would be 13,000 to 34,000 fewer premature deaths
annually. Avoided deaths and other benefits occur throughout the East, Midwest, and South,
according to EPA, with Ohio and Pennsylvania benefitting the most.30
Judicial and Legislative Options for Overturning the Cross-State Rule
In the 112th Congress, both the House and Senate considered legislation that would have revoked
the Cross-State rule. The House bill (H.R. 2401) passed 249-169 on September 23, 2011. It would
have declared the rule “of no force and effect,” reinstating the CAIR rule in its place. The bill
would also have required a study of the cumulative impact of the Cross-State Rule and about a

27 The acid rain program, established by the Clean Air Act Amendments of 1990, set up a cap-and-trade program for
sulfur dioxide emissions from electric generating units. Implementation began in 1995. The NOx SIP Call,
implemented in 2004, is a cap-and-trade program for control of nitrogen oxide emissions in the eastern half of the
country.
28 Data are from EPA’s National Emissions Inventory, at http://www.epa.gov/ttn/chief/trends/.
29 The final rule appeared in the Federal Register August 8, 2011. See U.S. EPA, Federal Implementation Plans:
Interstate Transport of Fine Particulate Matter and Ozone and Correction of SIP Approvals, 76 Federal Register 48208.
Background material can be found on EPA’s website at http://www.epa.gov/crossstaterule/actions.html.
30 U.S. EPA, Office of Air and Radiation, “Final Air Pollution Cross-State Air Pollution Rule,” Overview Presentation,
undated, pp. 12-14, at http://www.epa.gov/crossstaterule/pdfs/CSAPRPresentation.pdf.
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dozen other regulatory actions, would have prohibited EPA from proposing a replacement until at
least three years after completion of the study, and would have provided at least a further three
years after promulgation before compliance could be required; it would also have required that
any replacement rule allow trading of emission allowances among entities in all affected states.
The Senate did not take up the House bill, but it did consider S.J.Res. 27, a resolution of
disapproval of the rule under the Congressional Review Act (CRA). If a CRA resolution
disapproving a rule is enacted, the rule cannot take effect, and the agency may not reissue either
that rule or any substantially similar one, except under authority of a subsequently enacted law.
S.J.Res. 27 was rejected by the Senate, 41-56, on November 10, 2011.
Although unsuccessful in Congress, opponents of the rule did prevail in court. At least 45 parties
filed suit asking the D.C Circuit Court of Appeals to review the rule (the cases were consolidated
as EME Homer City Generation L.P. v. EPA ). On August 21, 2012, in a 2-1 decision, the court
vacated and remanded the rule, finding that EPA’s imposition of Federal Implementation Plans,
without first giving the states an opportunity to develop their own plans, was unlawful. The court
also held that EPA’s emission budgets (which were based on what the agency considered cost-
effective controls) may require states to reduce their emissions by amounts greater than their
significant contribution to nonattainment in downwind states.31 The agency subsequently asked
the full D.C. Circuit to review the decision en banc. As of December 2012, the court had not ruled
on the agency’s request.
The Utility MACT/MATS Rule: Addressing Mercury and Other
Hazardous Air Pollutants
Background
The Clean Air Act also provides authority for EPA to regulate emissions of mercury and other
hazardous air pollutants (HAPs, or “air toxics”) from electric generation units. Much of this
discussion has focused on mercury. Electric generating units account for about half of all mercury
emissions in the United States.
Mercury is a potent neurotoxin that can cause adverse health effects (principally delayed
development, neurological defects, and lower IQ in fetuses and children) at very low
concentrations.32 The principal route of exposure to mercury is through consumption of fish.
Mercury enters water bodies, often through air emissions, and is taken up through the food chain,
ultimately affecting humans as a result of fish consumption. As noted earlier, all 50 states have
issued fish consumption advisories due to mercury pollution, covering 16.8 million acres of lakes,
1.25 million river miles, and the coastal waters of 20 entire states.
Regulation of mercury emissions from coal-fired power plants has a complicated legislative and
regulatory history, dating back to the 1990 Clean Air Act Amendments. EPA was required by that
legislation and a 1998 consent agreement to determine whether regulation of mercury from power
plants under Section 112 of the Clean Air Act was appropriate and necessary. Section 112 is the
section that regulates emissions of hazardous air pollutants. In general, it requires EPA to set
standards based on the Maximum Achievable Control Technology (a term defined with great
precision in the act), and to impose the MACT standards at each individual emissions source. In a

31 EME Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012).
32 For a discussion of mercury’s health effects, see CRS Report RL32420, Mercury in the Environment: Sources and
Health Risks.
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December 2000 regulatory finding, EPA concluded that regulation of mercury from power plants
under Section 112 was appropriate and necessary. The finding added coal- and oil-fired electric
generating units to the list of sources of hazardous air pollutants, and triggered other provisions of
the 1998 consent agreement: the agency was to propose MACT standards for them by December
15, 2003, and finalize the standards by March 15, 2005.
Rather than promulgate MACT standards, however, EPA reversed its December 2000 finding in
March 2005, and established through regulations a national cap-and-trade system for power plant
emissions of mercury, the Clean Air Mercury Rule (CAMR). Under CAMR, the final cap would
have been 15 tons of emissions nationwide in 2018 (about a 70% reduction from 1999 levels,
when achieved). There would also have been an intermediate cap of 38 tons in 2010, well above
EPA’s projection of emissions in that year.33
Under the cap-and-trade system, utilities could either control the pollutant directly or purchase
excess allowances from other plants that instituted controls more stringently or sooner than
required. As with the acid rain and CAIR cap-and-trade programs, early reductions under CAMR
could have been banked for later use, which the agency itself said would result in utilities
delaying compliance with the full 70% reduction until after 2025.34 (For additional information
on the mercury rule, see CRS Report RL32868, Mercury Emissions from Electric Power Plants:
An Analysis of EPA’s Cap-and-Trade Regulations.)
New Jersey v. EPA
The CAMR rule was challenged in petitions for review filed by New Jersey and 16 other states as
well as other petitioners.35 The D.C. Circuit, in a 3-0 decision handed down February 8, 2008,36
vacated the rule. The court found that once the agency had listed electric generating units (EGUs)
as a source of hazardous air pollutants, it had to proceed with MACT regulations under Section
112 of the act unless it “delisted” the source category, under procedures the act sets forth in
Section 112(c)(9). Delisting would have required the agency to find that no EGU’s emissions
exceeded a level adequate to protect public health with an ample margin of safety, and that no
adverse environmental effect would result from any source—a difficult test to meet, given the
agency’s estimate that EGUs were responsible for 46% of mercury emissions from all U.S.
sources at the time. Rather than delist the EGU source category, the agency had maintained that it
could simply reverse its December 2000 “appropriate and necessary” finding, a decision that was
much simpler because there were no statutory criteria to meet. The court found this approach
unlawful. “This explanation deploys the logic of the Queen of Hearts, substituting EPA’s desires
for the plain text of Section 112(c)(9),” the court said in its opinion.37
Other Mercury/Air Toxics Issues
Besides the question of whether EPA complied with the law’s requirements, critics found other
reasons to oppose EPA’s cap-and-trade approach to controlling mercury. One of the main
criticisms has been that it would not address “hot spots,” areas where mercury emissions and/or

33 The agency projected emissions at 31 tons in 2010 even if 99% of the generating units installed no mercury control
equipment.
34 U.S. EPA, Regulatory Impact Analysis of the Final Clean Air Mercury Rule, Table 7-3, p. 7-5, at
http://www.epa.gov/ttnecas1/regdata/RIAs/mercury_ria_final.pdf.
35 Seven other states joined EPA in defending the rule.
36 New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008).
37 Id. at 582.
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concentrations in water bodies are greater than elsewhere. In fact, under a cap-and-trade system,
nothing would prevent emissions from increasing at hot spots.
Many also argued that the mercury regulations should have been more stringent or implemented
more quickly than the cap-and-trade regulations would have required. These arguments found a
receptive audience in the states: about 20 states have promulgated requirements stricter than the
federal Clean Air Mercury Rule program, with several requiring 80% to 90% mercury reductions
before 2010. (For additional information, see archived CRS Report RL33535, Mercury Emissions
from Electric Power Plants: States Are Setting Stricter Limits.)
Another shortcoming of the 2005 Clean Air Mercury Rule was that it didn’t address emissions of
hazardous air pollutants other than mercury. In the analysis accompanying EPA’s current
proposal, the agency states that EGUs are sources of 12 other HAPs, including three acid gases
and nine toxic metals.
The Utility MACT/Mercury and Air Toxics Standards
On December 21, 2011, EPA responded to the New Jersey v. EPA court decision by finalizing
what is referred to as the “Utility MACT” or, more recently, the Mercury and Air Toxics
Standards (MATS).38 A proposed version that appeared in the Federal Register on May 3, 2011,
began a public comment period that ran through August 4 of that year. Public hearings were held
in Atlanta, Chicago, and Philadelphia, and the agency was reported to have received 960,000
public comments.
The Utility MACT will require coal-fired power plants to achieve about a 90% reduction from
uncontrolled emissions of mercury, nine other toxic metals, and three acid gases, all of which
were listed by Congress as hazardous air pollutants in the 1990 Clean Air Act Amendments.
Power plants are the largest emitters of many of these pollutants, accounting for about 50% of the
nation’s mercury emissions, 62% of its arsenic emissions, and 82% of its hydrochloric acid
emissions, for example.39 The Utility MACT will also reduce emissions of fine particulates
(PM2.5).
In proposing the standards, EPA noted that while the requirements are stringent for those facilities
lacking controls, 56% of existing coal-fired power plants already are equipped with controls that
will allow them to meet the standards. Thus, the standards are expected to level the playing field,
bringing older, poorly controlled plants up to the standards that a majority of the existing units are
able to achieve.40 In this respect, the proposed standards reflect the statute’s requirement that
existing sources of HAPs should meet standards based on the current emissions of the best
performing similar sources.
New facilities face more stringent requirements than existing units. Whether the new unit
standards are achievable has been one of the issues raised by stakeholders, including the
manufacturers of emissions control and monitoring equipment. The latter have focused on the
standard for mercury emissions from new plants, questioning whether available monitoring

38 The rule appeared in the Federal Register, February 16, 2012, at 77 Federal Register 9304. For a link to the rule as
well as explanatory material, see U.S. EPA, “Final Mercury and Air Toxics Standards (MATS) for Power Plants,” at
http://www.epa.gov/airquality/powerplanttoxics/actions.html.
39 See U.S. EPA, “Memorandum: Emissions Overview: Hazardous Air Pollutants in Support of the Final Mercury and
Air Toxics Standard,” November 2011, Tables 4, 5, and 6, at http://www.epa.gov/airquality/powerplanttoxics/pdfs/
20111216EmissionsOverviewMemo.pdf.
40 The agency also concludes that some plants, representing less than 10 Gw of coal-fired capacity, would be retired by
2015, rather than invest in control technologies. In all, it says, coal-fired generation would decline about 2%.
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equipment can detect mercury emissions at the level required by the standards. EPA agreed to
reconsider this issue, and stayed implementation of the new source portion of the standards.
On November 16, 2012, the agency proposed to modify the rule’s standards for mercury
emissions from new coal-fired power plants:41 the proposed standard, if finalized, will allow 15
times as much mercury to be emitted as would have been allowed under the standard finalized in
December 2011.
The reconsideration would also make new source standards for particulate matter and hydrogen
chloride less stringent, allowing 13 times as much particulate matter and 25 times as much
hydrogen chloride; these changes were based on the agency’s conclusion that it had not used all
the available emissions information in the record when it promulgated the December 2011
standards. The agency says that the proposed changes will result in “no significant change in
costs, emission reductions or health benefits from MATS.” Facilities would still need the same
pollution control equipment to meet the less stringent standards.42
Costs, Benefits, Technology, and Timing
EPA projects the annual cost of compliance with the MATS standards at $9.6 billion. The average
consumer would see an increase of $3-$4 per month in the cost of electricity due to the rule,
according to the agency. These costs will go largely to the installation of scrubbers, activated
carbon or sorbent injection, and fabric filters. As a result of the rule, 20 gigawatts (GW) of coal-
fired units, about 7% of total coal-fired capacity, are expected to install scrubbers and 63 GW
(roughly 20%) will upgrade existing scrubbers. (EPA estimates that 203 GW will have already
installed scrubbers by 2015, as a result of other regulations.)
One-third of the coal-fired EGU capacity (102 GW) are expected to add fabric filters because of
the rule, while 90 GW would have them in the base case. In most cases, the fabric filters will be
coupled with activated carbon injection or dry sorbent injection. Mercury and other HAPs
become attached to the carbon or sorbent after it is injected into the flue gas, and the fabric filter
collects the particles, removing them from the plant’s emissions.
This is not complicated or new technology. Other types of facilities (notably solid waste
incinerators) have used this technology for the past 15 years to reduce their mercury emissions by
95% or more. As a result of state-level pollution control regulations, a growing percentage of
coal-fired plants do the same. EPA estimates that 16 GW of coal-fired capacity (about 5% of the
U.S. total) would have either activated carbon or dry sorbent injection in 2015 without the rule.
The rule adds another 184 GW (roughly 60%) of carbon/sorbent installations.
The benefits of the rule are estimated by EPA at $37 billion to $90 billion annually—4 to 9 times
as great as the costs—due primarily to the avoidance of up to 11,000 premature deaths each year.
Other benefits, only some of which were given dollar values, include the annual avoidance of
4,700 nonfatal heart attacks, 130,000 asthma attacks, and developmental effects on children,
including effects on IQ, learning, and memory.

41 U.S. EPA, “Reconsideration of Certain New Source and Startup/Shutdown Issues: National Emission Standards for
Hazardous Air Pollutants from Coal- and Oil-Fired Electric Utility Steam Generating Units and Standards of
Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-
Commercial-Institutional Steam Generating Units,” Proposed Rules, November 16, 2012, at http://www.epa.gov/
airquality/powerplanttoxics/pdfs/20121116proposal.pdf.
42 U.S. EPA, “Fact Sheet, Proposed Updates of the Limits for New Power Plants Under the Mercury and Air Toxics
Standards (MATS),” at http://www.epa.gov/airquality/powerplanttoxics/pdfs/20121116factsheet.pdf. See also 77
Federal Register 71333, November 30, 2012.
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Besides the achievability of some of the standards, a major issue raised by the MATS rule is
whether it gives power companies sufficient time to install controls and whether the costs will
lead companies to retire coal-fired generation rather than consider retrofits, thus threatening the
reliability of the nation’s power supply. Although many in the electric power industry have argued
these points, a review of industry data available through the North American Electric Reliability
Corporation suggests that the rule will not generally threaten electric reliability. For additional
information, see CRS Report R42144, EPA’s Utility MACT: Will the Lights Go Out?
Following EPA’s promulgation of the rule, Senator Inhofe introduced S.J.Res. 37, a resolution to
disapprove it under the Congressional Review Act (CRA). As mentioned earlier, if a CRA
resolution disapproving a rule is enacted, the rule cannot take effect, and the agency may not
reissue either that rule or any substantially similar one, except under authority of a subsequently
enacted law. S.J.Res. 37 was rejected by the Senate, June 20, 2012, 46-53.
Cumulative Impacts of EPA Rules
As EPA has developed and proposed standards for electric generating units, utilities that rely
heavily on coal-fired power and the industry’s trade association, the Edison Electric Institute
(EEI), have raised concerns about the cumulative impacts of EPA rules. Besides the Cross-State
Rule and the Utility MACT, their attention has focused on proposed Clean Water Act rules for
cooling water intake structures, proposed Solid Waste Disposal Act standards for managing coal
combustion wastes, and recently-proposed Clean Air Act standards for emissions of greenhouse
gases. Cumulatively, many in the industry and other opponents of these regulations have referred
to these rules as an impending “train wreck” for coal-fired power plants. They maintain that
compliance will be difficult and costly within the mandated timeframes, and that, as a result,
sections of the country depending on coal-fired power could experience electricity reliability
problems as plants are retired or taken off-line for retrofit of pollution controls.
Others in the industry and in various think tanks have concluded that this is unlikely to be the
case. They note that the studies sponsored by EEI and by coal-reliant utilities were generally
written before EPA proposed or promulgated any of the actual regulations, and the studies often
assumed far more stringent requirements than EPA actually proposed. While it is true that many
coal-fired units would have to be taken out of service for pollution control equipment to be
installed, the next few years would be an opportune time to do so, as there is currently substantial
excess generating capacity in the electric power industry. This reserve margin will continue to be
available over the next 5-10 years: as a result of the recession and the slow pace of economic
recovery, demand for electricity is growing slowly.
Many observers note, too, that EPA regulation is only one element of the situation facing aging
coal-fired power plants, many of which are more than 40 years old and have few pollution
controls. Equally important is competition from more efficient natural gas combined cycle units,
which have taken over a larger share of the electric power market as the price of natural gas has
declined. Over the last two decades, more than 80% of new generating capacity has come from
these gas-fired units, which are relatively cheap to build and are cleaner and more efficient to
operate than most coal-fired units. Observing the inroads being made by gas-fired generation,
many industry observers conclude that portions of the electric power industry are simply
experiencing a transition to more efficient power generation sources. If the cost of making a coal-
fired plant more efficient and less polluting is higher than that of converting to natural gas, the
plant may well be retired. This can cause economic dislocation in specific communities, but it
might not cause a substantial increase in the price of electricity or threaten the reliability of
electricity supply. For additional information on this subject, see CRS Report R41914, EPA’s
Regulation of Coal-Fired Power: Is a “Train Wreck” Coming?
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Legislation to address the cumulative impacts issue was introduced in both the House and Senate
in the 112th Congress. H.R. 2401, the Transparency in Regulatory Analysis of Impacts on the
Nation (TRAIN) Act of 2011, which the House passed September 23, 2011, would have
established a panel of representatives from 11 federal agencies to report to Congress by August
2012 on the cumulative economic impact of a number of listed EPA rules, guidelines, and actions
concerning clean air and waste management. It would have rendered both the Cross-State rule
and the Utility MACT “of no force and effect”; it would have reinstated the CAIR rule to replace
the Cross-State rule for at least six years following enactment, and required that any subsequent
replacement allow trading of emission allowances among entities irrespective of the states in
which they are located; it would have delayed promulgation of a replacement for the Utility
MACT until at least one year after submission of the cumulative impacts report and delayed
compliance for at least five years after that date; it would have required that the Utility MACT
replacement impose the least burdensome regulatory alternative from among the alternatives
authorized under the Clean Air Act; and it would have required EPA to take into consideration
feasibility and cost in setting health-based ambient air quality standards. The TRAIN Act passed
the House a second time as Title III of H.R. 3409, the Stop the War on Coal Act, September 21,
2012. The Senate did not consider either bill.
Air Quality Standards
Background
Air quality has improved substantially since the passage of the Clean Air Act in 1970: annual
emissions of the six most widespread (“criteria”) air pollutants43 have declined by 202 million
tons (71%), despite major increases in population, motor vehicle miles traveled, and economic
activity.44 Nevertheless, the goal of clean air continues to elude many areas, in part because
scientific understanding of the health effects of air pollution has caused EPA to tighten standards
for most of the criteria pollutants. Congress anticipated that the understanding of air pollution’s
effects on public health and welfare would change with time, and it required, in Section 109(d) of
the act, that EPA review the standards at five-year intervals and revise them, as appropriate.
The most widespread problems involve ozone and fine particles. As of December 2012, 118
million people lived in areas classified “nonattainment” for the ozone National Ambient Air
Quality Standard (NAAQS);45 74 million lived in areas that were nonattainment for the fine
particle (PM2.5) NAAQS.46 EPA attributes at least 33,000 premature deaths and millions of lost
work days annually to exceedances of the PM2.5 standard. Recent research has tied ozone
pollution to premature mortality as well.

43 The six criteria air pollutants are ozone, particulate matter, sulfur dioxide, carbon monoxide, nitrogen dioxide, and
lead. Criteria pollutants, identified by the EPA Administrator, are pollutants that (a) cause or contribute to air pollution
which may reasonably be anticipated to endanger public health or welfare, and (b) the presence of which in the ambient
air results from numerous or diverse mobile or stationary sources (§108(a)(1) of the Clean Air Act).
44 See U.S. EPA, “Air Quality Trends,” at http://www.epa.gov/airtrends/aqtrends.html#comparison. Data for 1970 are
available at http://www.epa.gov/airtrends/images/comparison70.jpg.
45 Data for ozone nonattainment areas are from the U.S. EPA “Green Book,” at http://www.epa.gov/oar/oaqps/greenbk/
gntc.html.
46 Fine particles, as defined by EPA, consist of particulate matter 2.5 micrometers or less in diameter, abbreviated as
PM2.5. Data for PM2.5 nonattainment areas are also from the U.S. EPA “Green Book,” at http://www.epa.gov/oar/oaqps/
greenbk/rnsum.html.
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Violations of the ambient air quality standards for the other four criteria pollutants are not as
widespread, but EPA has recently completed reviews indicating that health effects of most of
these pollutants are more serious than previously thought. At present, for example, only nine
areas with a combined population of about 1.2 million exceed the NAAQS for sulfur dioxide
(SO2), but in a recent review, EPA determined that between 2,300 and 5,900 premature deaths can
be avoided annually by strengthening that standard. Thus, the agency has promulgated a new SO2
standard under which as many as 59 counties could be designated nonattainment, based on the
most recent monitoring data.47
Table 1 summarizes EPA’s recent efforts to review the NAAQS and implement revisions,
including the next steps for each of the six criteria pollutants. Reviews of all six pollutants
(ozone, PM, lead, NO2, carbon monoxide, and SO2) have been completed since 2006, with the
standards being made more stringent for five of the six.48 The next round of reviews has begun
for ozone and lead.
Reviews don’t always lead to revision of the standards. On August 31, 2011, the EPA
Administrator completed a review of the carbon monoxide (CO) NAAQS without changing the
standard. The CO standard was promulgated in its present form in 1971.
Judicial Reviews
As the table indicates, court challenges have played a key role in bringing about the NAAQS
reviews, and in causing further review after the NAAQS have been promulgated. Reviews of
most of the standards were stimulated at least in part by court cases: because EPA is statutorily
required to review the NAAQS every five years, its failure to do so can be addressed by citizen
suits.
At the other end of the process, once the agency’s review of a NAAQS is completed, the
standards are almost invariably challenged in court. In the case of both particulate matter (PM)
and ozone, judicial review led to a remand of the standards that EPA promulgated in 2006 and
2008, respectively.
Table 1. Status of NAAQS Reviews
Last
Court
Monitoring
Pollutant
Revision
Action?
Next Steps
Issues?
Comments
ozone
Last revision
In response to
46 areas were designated
Only 675 of
The March
(for
was March
suits filed by
nonattainment for the
the nation’s
2008 primary
additional
27, 2008.
15 states
2008 standard in April
3,000 counties
(health-
information,
Revised
(Mississippi v.
and May 2012. By 2015,
have ozone
based)
see archived
standards
EPA), EPA
they wil have to submit
monitors: At
standards
CRS Report
were
agreed to
State Implementation
least 515 of
were set at a
R41062,
proposed
reconsider the
Plan revisions
these counties
level less
Ozone Air
January 19,
March 2008
demonstrating how they
exceeded the
stringent than
Quality
2010, but
standards.
wil reach attainment.
standard
recommende

47 http://www.epa.gov/air/sulfurdioxide/pdfs/20100602map0709.pdf. The 59 potential nonattainment counties were
identified using the most recent available monitoring data at the time the standard was promulgated (2007-2009).
48 Carbon monoxide is the only NAAQS that was left unchanged after review. Four of the six reviews were
subsequently challenged in court and the NAAQS for two of these four (ozone and particulates) were remanded to the
agency for further revisions. There are CRS reports on three of the NAAQS revisions: CRS Report R41062, Ozone Air
Quality Standards: EPA’s Proposed Revisions, CRS Report R42671, Air Quality: EPA’s 2012 Proposed Changes to
the Particulate Matter (PM) Standard , and CRS Report RL34479, Revising the National Ambient Air Quality Standard
for Lead.
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Last
Court
Monitoring
Pollutant
Revision
Action?
Next Steps
Issues?
Comments
Standards:
withdrawn
Court review
EPA has begun its next
proposed in
d by EPA’s
EPA’s
September 2,
and
five-year review of the
2010 based on
science
Proposed
2011.
Implementatio
ozone NAAQS and
the most
advisers. The
Revisions)
n of the 2008
expects to propose any
recent
revision also
NAAQS were
changes in 2013.
monitoring
did not act
stayed pending
data available
on proposed
review, but
at that time.
changes to
both have
Ozone is
the form of
resumed
increasingly
the
fol owing the
seen as a
secondary
September
regional
(welfare)
2011 decision.
pol utant that
standard that
affects rural as
would have
well as urban
more
areas, so
accurately
more counties
addressed
may need
impacts on
monitors. On
crops and
July 14, 2009,
forests. The
EPA proposed
January 2010
to require
proposal
that states
would have
monitor
addressed
ozone
both of these
concentration
issues.
s in rural as
well as urban
areas.
particulate
On
The D.C.
The EPA Administrator
Environmental EPA projects
matter
December
Circuit
signed final revisions to
groups would
relatively low
(PM2.5 and
14, 2012,
remanded the
the standards December
like to see
costs of
PM10)
EPA revised
2006 PM2.5
14, 2012. The revisions
additional
compliance
(for
the annual
standards to
should appear in the
monitoring in
because other
additional
PM2.5
EPA in
Federal Register shortly
areas with
regulations
information,
standard. The
February 2009
thereafter, fol owing
expected high
(including
see CRS
PM10
(American
which states and EPA will
concentration
more stringent
Report
standard and
Farm Bureau
review monitoring data
s (e.g., along
emission
R42671, Air
the 24-hour
Federation v.
to designate areas in
highways, near standards for
Quality: EPA’s
standard for
EPA). The
nonattainment of the
ports, etc.).
mobile and
2012
PM2.5,
2012 revision
standards, probably in
As part of the
stationary
Proposed
established in
addresses
late 2014. New
revisions to
sources that
Changes to
1997 and
both the
monitoring requirements
the PM2.5
have already
the Particulate
2006
court’s
wil be phased in by
standards,
been
Matter (PM)
respectively,
remand and
2017.
EPA updated
promulgated)
Standard
were not
the regular
monitoring
are projected
changed.
five-year
requirements
to reduce
review
for fine
ambient PM
required by
particles,
concentrations
the Clean Air
including
.
Act.
adding a
requirement
for monitoring
near heavily
traveled roads
in large urban
areas.
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Clean Air Issues in the 112th Congress

Last
Court
Monitoring
Pollutant
Revision
Action?
Next Steps
Issues?
Comments
sulfur
On June 22,
The D.C.
EPA intends to designate
The current
Since 1971,
dioxide
2010, EPA
Circuit
nonattainment areas by
SO2
EPA had
(SO2)
revised the
remanded the
June 2013. Some areas
monitoring
conducted
NAAQS,
SO2 standard
wil be designated
network was
three reviews
focusing on
to EPA in
sooner.
not primarily
of the SO2
shorter-term
1998,
A coalition of
configured to
standards
(1-hour)
fol owing an
manufacturers has sued
monitor
without
exposures.
agency review
EPA to overturn the new
locations of
changing
The prior
that left the
standards (National
maximum
them.
standards
standard
Environmental
short-term
(for 24-hour
unchanged.
Development Association’s
concentration
and annual
The court
Clean Air Project v. EPA).
s. The
concentratio
found the
network
ns), which
Administrator
needs 41 new
were
had failed
monitoring
revoked as
adequately to
sites,
part of the
explain her
according to
revision,
conclusion
EPA. In a
were set in
that no public
change from
1971. The
health threat
the agency’s
new short-
existed from
December
term
short term
2009
standard is
exposures to
proposal, EPA
substantially
SO2. (American
wil rely
more
Lung
primarily on
stringent,
Association v.
dispersion
replacing a
EPA)
modeling to
24-hour
assess
standard of
compliance
140 parts per
with the
bil ion (ppb)
standard.
with a 1-hour
maximum of
75 ppb.
carbon
Current
The U.S.
EPA’s August 2011
Although it
National
monoxide
primary
District Court
decision is being
did not change
average
(CO)
standard was
for the
challenged by
the standard
concentratio
set in 1971.
Northern
environmental groups
in its 2011
n of CO,
EPA revoked
District of
(Communities for a Better
review, EPA
which is
a secondary
California
Environment v. EPA).
did revise the
emitted
standard in
ordered EPA
CO
largely from
1985.
to review the
monitoring
motor
CO NAAQS
requirements
vehicles, has
by August 12,
to establish a
declined 82%
2011
more focused
since 1980,
(Communities
monitoring
and no areas
for a Better
network, with
violate the
Environment v.
CO monitors
existing CO
EPA). At the
to be placed
NAAQS,
conclusion of
near highly
using
that review,
trafficked
readings from
EPA decided
roads in urban
the current
to retain the
areas with
monitoring
1971 standard.
populations of
network.
1 mil ion or
Standards for
CO were
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Clean Air Issues in the 112th Congress

Last
Court
Monitoring
Pollutant
Revision
Action?
Next Steps
Issues?
Comments
more by 2015
retained
or 2017.
without
change
despite EPA’s
science
advisers
having stated,
“There is
consensus in
the Panel that
the current
standards
may not
protect
public health
with an
adequate
margin of
safety, and
therefore
revisions that
result in
lowering the
standards
should be
considered.”
nitrogen
EPA
A suit filed in
On February 17, 2012,
Under EPA’s
There are no
dioxide
completed a
2005 charged
EPA identified all areas as
new
nonattainmen
(NO2)
review and
that EPA had
“unclassifiable/attainment
monitoring
t areas for
promulgated
failed to
.” Many of these are
network, a
the annual
a new 1-hour
review the
unclassifiable due to the
monitor wil
standard.
standard
NO2 standard
lack of adequate
be required
NO2
February 9,
in the last 5
monitoring. Once an
near a major
emissions
2010. The
years, as
expanded network of
road in any
have been
new standard
required by
NO2 monitors is ful y
urban area
more
is in addition
the Clean Air
deployed and three years
with a
stringently
to the
Act (Center for
of air quality data have
population of
control ed
previous
Biological
been col ected, the
350,000 or
even though
annual
Diversity v.
agency wil redesignate
more. (The
there have
average
Johnson).
areas (in 2016 or 2017)
majority of
not been
standard,
Under a 2007
based on air quality data
NO2
recent
which was
consent
from the new monitoring
emissions
violations of
set in 1971.
decree, EPA
network.
come from
the NO2
proposed
motor
standard,
revisions to
vehicles.)
because
the primary
Community-
nitrogen
standard July
wide
oxides
15, 2009, and
concentration
contribute to
promulgated
s would also
the formation
the revisions
be monitored
of ozone, the
in February
in urban areas
standard for
2010.
with
which has
populations of
been
1,000,000 or
reviewed and
more.
strengthened
several times.
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Clean Air Issues in the 112th Congress

Last
Court
Monitoring
Pollutant
Revision
Action?
Next Steps
Issues?
Comments
lead
November
Both
Revised monitoring rules
In July 2009,
EPA’s
(for
12, 2008
environmental
were proposed
EPA agreed to
November
additional
groups (which
December 23, 2009.
review the
2008 action
information,
challenged the
Sixteen nonattainment
monitoring
reduced the
see archived
adequacy of
areas were designated in
portions of its
standard by
CRS Report
the monitoring
November 2010.
November
90%, from 1.5
RL34479,
requirements)
2008 NAAQS.
micrograms
EPA has begun a review
Revising the
and industry
At least 24 of
per cubic
of the 2008 NAAQS and
National
(which
the 50 states,
meter
expects to complete it by
Ambient Air
challenged the
including some
(μg/m3) to
2014.
Quality
standard itself)
with major
0.15 μg/m3.
Standard for
petitioned for
sources of
Lead.
review
lead emissions,
(Missouri
had no lead
Coalition for the
monitors at
Environment v.
all. Under the
EPA and
2008
Coalition of
regulations,
Battery
101 metro
Recyclers
areas (those
Association v.
with
EPA). EPA
populations
granted a
greater than
petition for
500,000)
reconsideratio
would be
n of the
required to
monitoring
have monitors
requirements
as would an
in July 2009. In
estimated 135
the industry
areas that have
case, the D.C.
sources of
Circuit upheld
lead emissions
the standards,
greater than
May 14, 2010.
or equal to
one ton per
year.
Proposed
regulations
would lower
the source
threshold to
0.5 tons.
CASAC’s Role
In making his decisions regarding the 2008 ozone and 2006 particulate standards, then-EPA
Administrator Stephen Johnson did not follow the advice of the agency’s independent science
advisors, the Clean Air Scientific Advisory Committee (CASAC). The Administrator is not
required by statute to follow CASAC’s recommendations; the act requires only that he set forth in
the Federal Register notice in which he (or she) proposes a NAAQS any pertinent findings,
recommendations, and comments made by CASAC and, if the proposal differs in an important
respect from any of the recommendations, provide an explanation of the reasons for such
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Clean Air Issues in the 112th Congress

differences.49 But the failure to follow CASAC recommendations almost inevitably raises the
question of whether the Administrator’s decision will be judged arbitrary and capricious in a
judicial review.
In the 2006 and 2008 revisions of the PM and ozone standards, CASAC made detailed objections
to the Administrator’s final decisions. The committee’s description of the process as having failed
to meet statutory and procedural requirements could still play a role during judicial review of the
ozone decision. This raises the question of whether Congress might reconsider CASAC’s
statutory role in the review process, or further specify the conditions under which the
Administrator may reject CASAC’s advice.
Adequacy of Monitoring
A feature common to many of the recent NAAQS reviews has been EPA’s finding that the current
monitoring network is inadequate to determine whether or not many areas of the country are in
attainment of the standards. In several cases, such as for lead and sulfur dioxide, more extensive
monitoring networks had been partly dismantled by the time the standards were reviewed, after
years of indicating compliance with older, less stringent standards.50 In other cases, such as PM
and NO2, the monitoring network was not designed to measure the kinds of exposure that current
research identifies as a cause of concern (e.g., exposure to fine particles near highways). As a
result, EPA and the states will need to devote resources in the next few years to expanding and
refocusing the monitoring networks in order to identify areas where air quality does not meet new
standards.
NAAQS Implementation
Although most of the NAAQS standards had been revised by late 2011—a process that could
ultimately stimulate billions of dollars in expenditures on pollution control—the impact of the
new standards will be gradual. A NAAQS does not directly limit emissions; rather, a primary
NAAQS represents the Administrator’s formal judgment regarding the level of ambient pollution
below which public health will be protected with an adequate margin of safety; a secondary
standard reflects her judgment as to the level of ambient pollution necessary to protect public
welfare, including protection of the environment, water quality, building materials, etc.
Promulgation of a NAAQS sets in motion a lengthy process under which states and the EPA first
identify nonattainment areas. Those areas then undertake a complicated implementation process.
The first step, designation of nonattainment areas, generally takes at least two years after a
standard is promulgated, and in many cases longer, if a new monitoring network needs to be
established. After nonattainment areas are formally designated, the states generally have three
years to submit State Implementation Plans (SIPs) that identify the specific regulations and
emission control requirements that will bring the area into attainment.
Whether more stringent NAAQS will lead to stronger federal emission controls for the sources of
pollution—in addition to the controls contemplated by individual states or metropolitan areas—is
likely to be an important issue. Several of the criteria pollutants have impacts across state lines,
far from the source of emissions; others (notably ozone) form in the atmosphere as the result of
chemical reactions involving precursors that may have been emitted many miles upwind. Thus,
measures taken by individual states and nonattainment areas to control emissions within their

49 The requirement is found in §307(d)(3) of the act.
50 Also, reductions in EPA grants to the states in some years may have resulted in the elimination of some monitoring
stations. EPA has concluded in some cases that modeling using data from remaining monitors could fill in data gaps.
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borders may be inadequate for the areas to attain a NAAQS. Federal standards for cars, trucks,
power plants, and other major pollution sources could need strengthening for many areas to be
able to attain the NAAQS.
Ozone and PM NAAQS Reviews
In the last three years, two NAAQS reviews, for ozone and for PM, have proven particularly
controversial. The next sections provide a brief discussion of the two reviews.
Ozone
On January 19, 2010, EPA proposed a revision to the NAAQS for ozone.51 The proposal did not
follow the usual five-year (or longer) review process, but resulted from the EPA Administrator’s
decision to reconsider standards promulgated in March 2008 by the previous Administration. The
2008 review had made the standards more stringent; but the Obama Administration’s EPA
suspended implementation of the new standard in September 2009 in order to consider further
strengthening it.
As proposed, the January 2010 revision would have lowered the primary (health-based) standard
from 75 parts per billion (ppb) averaged over 8 hours (the standard set in 2008) to somewhere in
the range of 70 to 60 ppb averaged over the same time; it would also have set a new secondary
standard designed to protect crops and forests from ozone. The proposal followed the
recommendations of CASAC, which had concluded that the 2008 revision did not meet the Clean
Air Act’s statutory requirements.
Because of its wide reach and potential cost, the proposed revision was among the most
controversial rules under consideration at EPA over the last three years. Although EPA is
prohibited by the statute52 from considering costs in setting NAAQS, it does prepare cost and
benefit estimates for information purposes. When it proposed the 2010 revisions, the agency
estimated that the costs of implementing the revised ozone NAAQS would range from $19 billion
to $25 billion annually in 2020 if the standard chosen were 70 ppb, or $52 billion to $90 billion if
the standard chosen were 60 ppb,53 with benefits of roughly the same amount. EPA identified at
least 515 counties that would violate the NAAQS if the most recent three years of data available
at the time of proposal were used to determine attainment (compared to 85 counties that violated
the 1997 standard in effect at that time).
Initially, the agency said it would complete the ozone review by August 2010, but it announced
delays in the projected completion date four times, before sending a final decision to the Office of
Management and Budget for interagency review in July 2011. The agency’s final decision would
have set a 70 ppb primary standard and would have adopted the new form of the secondary
standard that the agency had proposed. The agency’s cost estimate was unchanged from the

51 U.S. Environmental Protection Agency, “National Ambient Air Quality Standards for Ozone; Proposed Rule,” 75
Federal Register 2938, January 19, 2010.
52 The Clean Air Act’s §108 and §109 have been so interpreted since the NAAQS provisions were added to the act in
1970; in 2001, this interpretation was affirmed in a unanimous Supreme Court decision, Whitman v. American
Trucking Associations, 121 S. Ct. 903 (2001).
53 U.S. EPA, “Fact Sheet: Supplement to the Regulatory Impact Analysis for Ozone,” January 7, 2010, at
http://www.epa.gov/air/ozonepollution/pdfs/fs20100106ria.pdf.
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proposal—$19 billion to $25 billion in 2020—and benefits were estimated to be roughly the same
amount.54
On September 2, 2011, the White House announced that the President had requested that EPA
Administrator Jackson withdraw the all-but-final ozone standards from further consideration at
that time. The President’s statement noted that “work is already underway to update a 2006
review of the science that will result in the reconsideration of the ozone standard in 2013,” and
stated that he did not “support asking state and local governments to begin implementing a new
standard that will soon be reconsidered.”55
State and local governments will be asked to begin implementing a new standard that will soon be
reconsidered, however: withdrawal of the decision left EPA and state and local governments to
implement the 2008 ozone standards, which had been stayed pending the agency’s
reconsideration. It also meant that legal challenges to the 2008 standard (Mississippi v. EPA56),
which had been stayed pending reconsideration, can proceed. Oral argument in the Mississippi
case took place November 16, 2012. (For additional information on the ozone standards, see
archived CRS Report R41062, Ozone Air Quality Standards: EPA’s Proposed Revisions.)
Particulate Matter (including “Farm Dust”)
EPA completed a review of the NAAQS for particulate matter in 2006. The agency is required by
the Clean Air Act to complete a review of the standards at five-year intervals; thus, a review was
due in 2011. In 2009, the D.C. Circuit Court of Appeals remanded the 2006 PM2.5 standards to
EPA;57 as a result, EPA conducted the statutory five-year review of the standard and responded to
the D.C. Circuit decision through the same review, which the agency completed December 14,
2012.
The current NAAQS sets standards for both “fine” particulates (PM2.5) and larger, “coarse”
particles (PM10). EPA considers particulate matter to be among the most serious air pollutants,
responsible for tens of thousands of premature deaths annually.
Of the two types of particulates, the PM2.5 standards affect far more people and far more counties
than the standard for PM10, and both sets of standards have affected mostly industrial, urban
areas. Nevertheless, agricultural interests have made substantial efforts over the last year and a
half to assail a supposed EPA plan to regulate emissions of farm dust through the PM10 NAAQS
review, and have urged Congress to prevent the agency from doing so.
The Administrator stated as early as October 2011 that she did not intend to change the PM10
standard as a result of the current review.58 (And both the agency’s June 29, 2012, proposal and
its December 14, 2012, final action to revise the PM NAAQS followed through on the

54 See U.S. EPA, Regulatory Impact Analysis, Final National Ambient Air Quality Standard for Ozone, July 2011, p.6,
at http://www.epa.gov/airquality/ozonepollution/pdfs/201107_OMBdraft-OzoneRIA.pdf. The costs compared
implementation of a 70 ppb primary standard to the cost of compliance with the 1997 ozone standard. Implementing
the 2008 ozone standard, which the agency will now do, will cost $7.6 billion to $8.8 billion in 2020, according to the
same analysis.
55 The White House, Office of the Press Secretary, “Statement by the President on the Ozone National Ambient Air
Quality Standards,” September 2, 2011.
56 Mississippi v. EPA, No. 08-1200 (D.C. Cir. filed May 23, 2008).
57 American Farm Bureau Fed'n v. EPA, 559 F.3d 512 (D.C. Cir. 2009).
58 Letter of Lisa P. Jackson, EPA Administrator, to Senator Debbie Stabenow, October 14, 2011, at http://epa.gov/pm/
pdfs/20111014Stabenow.pdf. A similar letter was sent to Senator Amy Klobuchar.
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Administrator’s 2011 statements, making no change in the PM10 standard.59) Nevertheless, many
Members of Congress from farm states were skeptical of EPA’s intentions, and legislation was
introduced in the 112th Congress to prevent EPA from doing what it said it did not intend to do.
H.R. 1633, introduced by Representative Noem and cosponsored by 114 Members, would have
prohibited EPA from proposing or promulgating revisions to the NAAQS for particulates larger
than 2.5 micrometers in diameter for one year. Supporters of the bill described it as preventing
EPA from promulgating standards that would affect farm dust. Opponents noted that the language
of the bill would also have prevented EPA from setting standards for particles that are generated
by “other activities typically conducted in rural areas,” a category broad enough that it might
include industrial sources that are located in rural areas, such as mines. The bill passed the House,
268-150, December 8, 2011. In the Senate, S. 1528 and S. 1803 would have addressed the issue,
but neither bill was marked up.
For additional information on the PM standards, see CRS Report R42671, Air Quality: EPA’s
2012 Proposed Changes to the Particulate Matter (PM) Standard, by Robert Esworthy.
Other Issues
Since 2009, EPA has proposed and promulgated numerous regulations implementing the Clean
Air Act (and other pollution control statutes that it administers). Critics of the Administration,
both within Congress and outside of it, have accused the agency of reaching beyond the authority
given it by Congress and ignoring or underestimating the costs and economic impacts of these
rules. Particular attention has been paid to the Clean Air Act, under which EPA has moved
forward with the first federal controls on emissions of greenhouse gases and has proposed or
promulgated regulations for several major industries. In the 112th Congress, seven bills that would
overturn specific Clean Air Act regulations or limit the agency’s CAA authority (H.R. 1, H.R.
910, H.R. 1633, H.R. 2250, H.R. 2401, H.R. 2681, and H.R. 3409) passed the House.
Two of the regulations that attracted the most attention were the Maximum Achievable Control
Technology standards for cement kilns and boilers (referred to as the “Portland Cement MACT”
and the “Boiler MACT,” respectively).
Portland Cement MACT
The Portland Cement MACT was promulgated in September 2010, and compliance with its
emission standards was required by November 2013. Industry challenged these standards in the
D.C. Circuit Court of Appeals (Portland Cement Association v. EPA); the court remanded one
element of the standards to the agency, but it did not stay implementation of the rule.60
Meanwhile, cement kilns began negotiating permits based on the standards and designing and
installing equipment needed to comply.
In the 112th Congress, a majority of the House opposed the Portland cement standards, echoing
industry’s complaints that the standards were overly stringent and that the industry needed more
time to reduce emissions. On October 6, 2011, the House passed H.R. 2681, by a vote of 262-161.
The bill would have revoked EPA’s September 2010 standards as well as standards for
commercial and industrial incinerators (to the extent that they apply to cement kilns), and would

59 U.S. EPA, National Ambient Air Quality Standards for Particulate Matter, Proposed Rule, 77 Federal Register
38890, June 29, 2012.
60 On December 9, 2011, the D.C. Circuit Court of Appeals remanded the 2010 standards to EPA for the agency to
reconsider emission standards for kilns that use solid waste as fuel.
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have required their replacement with standards that represent the least burdensome regulatory
alternative. EPA would have been required to set a compliance date no earlier than six years and
three months after the date of enactment.
On April 20, 2012, the D.C. Circuit Court of Appeals approved a settlement under which EPA
agreed to reconsider the cement rule and its compliance deadline. The settlement called for EPA
to propose changes to the rule and whether it would change the compliance date by June 15,
2012.61 On June 22, 2012, the agency proposed changes to some of the emission limits and
monitoring requirements and an extension of the compliance date by two years, and, on
December 20, 2012, finalized these changes.62 The changes may have addressed the industry’s
main concerns. In reported comments, the president of the Portland cement industry’s trade
association said that the revised rule “strikes the right balance in establishing compliance limits
that, while still extremely challenging, are now realistic and achievable.”63 Environmental groups
were reportedly unhappy with the changes and may file suit challenging them.
Boiler MACT
The boiler standards were proposed June 4, 2010, and finalized February 21, 2011, but EPA itself
says it did not have sufficient time to review all available data submitted by commenters; so it
stayed implementation of the standards May 16, 2011, to allow for their reconsideration.64 The
agency re-proposed the standards December 2, 2011, and said it would complete the
reconsideration process by April 30, 2012.
Boilers are used as power sources throughout industry and for power or heat by large commercial
establishments and institutions. EPA estimated that the rule, as promulgated, would provide $22
billion to $54 billion in benefits annually, including the avoidance of 2,500 to 6,500 premature
deaths; but it would also impose annualized costs of $1.49 billion, according to the agency.
Opponents of the standards maintained that it would cost far more. As a result, there was
widespread interest in the rule’s requirements and their potential effects. (For a detailed
discussion, see CRS Report R41459, EPA’s Boiler MACT: Controlling Emissions of Hazardous
Air Pollutants.)
Bills were introduced in both the House and Senate (H.R. 2250 and S. 1392) to alter the rule’s
requirements and delay its implementation. H.R. 2250 passed the House October 13, 2011, 275-
142. A Senate amendment similar to H.R. 2250 (S.Amdt. 1660) failed on a vote of 52-46, March
8, 2012 (60 votes being necessary for adoption).
EPA finalized a revised version of the boiler rules on December 20, 2012. The revised rules made
numerous adjustments to the emission limits, making some more stringent and others less so, and
gave the largest boilers an additional two years (until 2016) to comply.65

61 “EPA to Reconsider Cement Kiln Standards Under Settlement Approved by D.C. Circuit,” Daily Environment
Report, April 24, 2012.
62 EPA’s final rule and a related fact sheet are available at http://www.epa.gov/airquality/cement/actions.html.
63 “EPA Gives Cement Kilns Two Extra Years to Comply With Revised Air Toxics Standards,” Daily Environment
Report, December 26, 2012.
64 On January 9, 2012, the Federal District Court for the District of Columbia overturned EPA’s stay of the February
2011 standards, but the reconsideration process for the standards will continue.
65 An EPA summary of the changes can be found at http://www.epa.gov/airquality/combustion/actions.html.
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EPA’s Position on Its Regulatory Actions
While EPA has been widely criticized by industry groups and many in Congress for overreaching,
the agency maintains that in promulgating these and other rules, it is complying with statutory
mandates placed on the agency by Congress. The agency states that its critics’ focus on the cost of
controls obscures the benefits of new regulations, which, it estimates, far exceed the costs; and it
maintains that pollution control is an important source of economic activity, exports, and
American jobs.
Environmental groups generally disagree that the agency has overreached in setting Clean Air Act
standards. These groups often maintain that the agency’s standards are not stringent enough,
don’t meet statutory requirements, or disregard the findings of the agency’s science advisors. The
result is that EPA Clean Air Act standards generally are challenged in court both by industry and
by environmental groups, with various states supporting each side. The resulting court decisions
often set EPA’s agenda as much as Congress or the Administration.
For additional discussion of EPA’s regulatory actions, both under the Clean Air Act and under
other statutes, see CRS Report R41561, EPA Regulations: Too Much, Too Little, or On Track?

Author Information

James E. McCarthy

Specialist in Environmental Policy

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
shared staff to congressional committees and Members of Congress. It operates solely at the behest of and
under the direction of Congress. Information in a CRS Report should not be relied upon for purposes other
than public understanding of information that has been provided by CRS to Members of Congress in
connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not
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Congressional Research Service
R41563 · VERSION 25 · UPDATED
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Dec. 31, 2012

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Sep. 4, 2012

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Nov. 17, 2011

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Topic areas

Environmental Policy

Report Type: CRS Report

Source: CRSReports.Congress.gov, University of North Texas Libraries Government Documents Department

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