Clean Air Issues in the 114th Congress:
An Overview
James E. McCarthy
Specialist in Environmental Policy
May 12, 2015
Congressional Research Service
7-5700
www.crs.gov
R43851
Clean Air Issues in the 114th Congress: An Overview
Summary
Oversight of Environmental Protection Agency (EPA) regulatory actions has received significant
attention in the early weeks of the 114th Congress. Of particular interest are two air quality issues:
EPA’s proposed regulations on the emissions of greenhouse gases (GHGs) from power plants, and
a proposed revision of the ambient air quality standard for ozone.
Reducing GHG emissions to address climate change is a major goal of President Obama, but
many in Congress have been less enthusiastic about it. In the absence of congressional action to
reduce emissions, the President has directed EPA to promulgate GHG standards using existing
authority under the Clean Air Act. This authority has been upheld on three occasions by the
Supreme Court, but it remains controversial in Congress.
In 2014, EPA proposed regulations to reduce GHG emissions from fossil-fueled (coal, oil, and
natural gas) power plants, which EPA refers to as electric generating units (EGUs). The agency
proposed standards for new EGUs in January 2014 and for existing units five months later. It
expects to finalize these rules in mid-summer 2015. EGUs are the source of one-third of the
nation’s GHG emissions, so it is difficult to envision a regulatory scheme that reduces the nation’s
GHG emissions without addressing their contribution. At the same time, affordable and reliable
electric power is central to the nation’s economy and to the health and well-being of the
population.
Thus, the effects of the proposed rule on the electric power system are of considerable interest.
Even before proposal of the existing power plant standards, the House had passed legislation
(H.R. 3826 in the 113th Congress) that would effectively have prohibited EPA from promulgating
or implementing power plant GHG emission standards. In September 2014, the House passed the
same language a second time, in H.R. 2. The Senate did not consider either bill.
In the 114th Congress, the Energy and Commerce Committee has ordered reported H.R. 2042,
which would delay the compliance date of GHG emission standards for EGUs, and would allow a
state to opt out of compliance if the governor determines that the rule would have an adverse
effect on rate-payers or have a significant adverse effect on the reliability of the state’s electricity
system.
Besides addressing climate change, EPA has taken action on a number of other air pollution
regulations, often in response to court actions remanding previous rules or setting deadlines for
actions that are non-discretionary under the Clean Air Act. Remanded rules included the Clean
Air Interstate Rule (CAIR) and 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. New rules—the Cross-State Air Pollution Rule (CSAPR) and the Mercury
and Air Toxics Standards (MATS)—have replaced those the court remanded. Both CSAPR and
MATS went into effect in 2015.
EPA is also reviewing national ambient air quality standards (NAAQS) for ozone. The agency
proposed revisions to the standards on December 17, 2014. NAAQS serve as EPA’s definition of
clean air for six widespread pollutants, and drive a range of regulatory controls. EPA is under a
court order to finish its review of the ozone NAAQS by October 1, 2015. As of early May, four
bills had been introduced to modify EPA’s authority or prohibit or delay the agency’s proposed
strengthening of the ozone standard.
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Clean Air Issues in the 114th Congress: An Overview
Contents
Introduction ...................................................................................................................................... 1
EPA’s Greenhouse Gas Regulations ................................................................................................. 1
GHG Emission Standards for Motor Vehicles ........................................................................... 2
GHG Emission Standards for Power Plants .............................................................................. 3
Legislative and Judicial Actions ................................................................................................ 4
Emissions of Other Pollutants from Power Plants ........................................................................... 6
CSAPR: Controlling SO2 and NOx ........................................................................................... 6
Mercury and Air Toxics Standards (MATS) .............................................................................. 7
Air Quality Standards ...................................................................................................................... 9
Background................................................................................................................................ 9
The Ozone NAAQS ................................................................................................................. 11
EPA’s December 2014 Proposal ........................................................................................ 11
Other Issues ................................................................................................................................... 13
Figures
Figure 1. Ozone Nonattainment Areas (2008 Standard, 0.075 ppm) ............................................. 10
Contacts
Author Contact Information........................................................................................................... 14
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Clean Air Issues in the 114th Congress: An Overview
Introduction
With Republican majorities in both the House and Senate, the 114th Congress may take action on
long-stalemated air quality issues. Congressional interest in the subject has been dominated for
the past five years by efforts to prevent the Environmental Protection Agency (EPA) from
promulgating and implementing new emission control requirements.
Often under court order, EPA has used authorities Congress gave it in the Clean Air Act
amendments of 1970, 1977, and 1990 over the last five years to address long-standing issues
posed by emissions from various sources. EPA’s regulations on greenhouse gas emissions from
both mobile and stationary sources and on emissions from electric power plants have been of
particular interest, as have the agency’s efforts to revise ambient air quality standards for ozone
and particulate matter.
Especially in the House, efforts to restrain agency regulatory actions have occupied a prominent
place. Until this year, however, bills to restrain EPA have faced a roadblock in the Senate, where
Democratic control largely prevented their consideration. With Republicans now in charge, the
Senate poses less of a roadblock. Still, environmental regulations are a key element of President
Obama’s legacy, so legislation restraining EPA—if passed by the House and Senate—could face a
Presidential veto. The net result—few environmental bills enacted—may remain as it has the last
five years.
In addition to bills targeting specific Clean Air Act rules, in recent years the House has also
considered broader legislation designed to address regulation in general—bills such as the REINS
Act (H.R. 427/S. 226 in the 114th Congress), which would require congressional approval before
regulations classified as major rules could take effect, or the Energy Consumers Relief Act (S.
156 in the 114th Congress), which would prohibit EPA from promulgating energy-related
regulations estimated to cost more than $1 billion if the Secretary of Energy determines that the
regulations will cause significant adverse effects to the economy. If enacted, such legislation
would affect new rules under the Clean Air Act as well as other statutes. Given the broad nature
of the bills’ purpose, they are not discussed here.1
EPA’s Greenhouse Gas Regulations
A continuing focus of congressional interest under the Clean Air Act (CAA) has been EPA
regulatory actions to limit greenhouse gas (GHG) emissions using existing CAA authority. EPA
actions have focused on six gases or groups of gases that multiple scientific studies have linked to
climate change.2 Of the six gases, carbon dioxide (CO2), produced by combustion of fossil fuels,
is by far the most prevalent, accounting for nearly 85% of annual emissions of the combined
group when measured as CO2 equivalents.
1 For information on the REINS Act, see CRS Legal Sidebar WSLG443, REINS Act and the Legislative Veto, by Daniel
T. Shedd.
2 The six are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons
(HFCs), and perfluorocarbons (PFCs).
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Members from both sides of the aisle, including a majority of the House in the 112th and 113th
Congresses, have expressed concerns about EPA proceeding with GHG regulations that could
have major economic impacts. Some argue that the case for GHG controls has not been proven.
Others maintain that EPA should delay taking such action until Congress more explicitly
authorizes it. EPA is on schedule to propose standards for GHG emissions from trucks in June
2015, and to finalize standards for power plants by mid-summer 2015, providing Congress
important opportunities to review the agency’s actions.
GHG Emission Standards for Motor Vehicles
Unlike its critics, EPA has concluded that the Clean Air Act requires action to control GHG
emissions, without the need for additional congressional authorization: a 2007 Supreme Court
decision interpreting EPA’s existing CAA authority, Massachusetts v. EPA,3 found that the agency
must weigh whether GHG emissions from new motor vehicles endanger public health and
welfare and, if it concludes that they do, proceed with regulation of such vehicles. The agency
made this endangerment finding in December 2009,4 and proceeded to promulgate GHG emission
standards for new 2012-2016 cars and light trucks, May 7, 2010.5
The prospect of GHG standards for motor vehicles has not been particularly controversial. In
May 2009, President Obama reached agreement with major U.S. and foreign auto manufacturers
and other stakeholders regarding the substance of GHG emission and related fuel economy
standards.6 The auto industry supported a 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. A second round of standards for cars and light trucks, promulgated in October
2012,7 was also preceded by an agreement with the auto industry and key stakeholders. CRS has
two reports that provide additional details.8
3 549 U.S. 497 (2007).
4 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 Greenhouse Gases Endanger Public Health and
Welfare, and a Finding That Emissions of Greenhouse Gases from CAA Section 202(a) Sources Cause or Contribute to
the Endangerment of Public Health and Welfare. [CAA Section 202(a) sources are new motor vehicles or new motor
vehicle engines.]
5 75 Federal Register 25324. For additional information, including a link to the standards, see http://www.epa.gov/otaq/
climate/regulations.htm#finalR. The agency subsequently (on October 15, 2012) promulgated GHG standards for
model years 2017-2025.
6 GHG emissions and fuel economy are directly related, because 94% of GHG emissions from light duty vehicles are
the result of fuel combustion. The less fuel a vehicle uses, the lower will be its GHG emissions.
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 R42721, Automobile and Truck Fuel Economy (CAFE) and Greenhouse Gas Standards,
by Brent D. Yacobucci, Bill Canis, and Richard K. Lattanzio, or CRS Report R40506, Cars, Trucks, and Climate: EPA
Regulation of Greenhouse Gases from Mobile Sources.
7 http://www.epa.gov/otaq/climate/regs-light-duty.htm#new1.
8 See CRS Report R40506, Cars, Trucks, and Climate: EPA Regulation of Greenhouse Gases from Mobile Sources,
and CRS Report R42721, Automobile and Truck Fuel Economy (CAFE) and Greenhouse Gas Standards.
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EPA and the National Highway Traffic Safety Administration (NHTSA) have also promulgated
joint GHG emission and fuel economy standards for medium- and heavy-duty trucks,9 which
have been supported by the affected industries. (For a brief summary of these, see CRS Report
R41563, Clean Air Issues in the 112th Congress.) In his 2014 State of the Union message and a
subsequent directive to EPA and NHTSA, the President directed the agencies to develop a second
round of these standards, to be proposed by March 2015 and finalized a year later.10 The rule is
now scheduled for proposal in June 2015.
GHG Emission Standards for Power Plants
The decisions to move forward on GHG standards for new motor vehicles were seen by many,
including EPA, as precedents for other potential standards. In December 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 2011, and for refineries by December 2011, with promulgation
by May 2012 and November 2012, respectively. Power plants are the largest anthropogenic
source of U.S. GHG emissions, accounting for one-third of the U.S. total. Petroleum refineries are
the second-largest industrial source of GHG emissions.
EPA has not fulfilled the terms of the two consent agreements. The agency has proposed the
standards for new and existing power plants but, other than that, has not yet taken the agreed-
upon actions.
The agency first proposed the power plant New Source Performance Standards (NSPS) on April
12, 2012. The Clean Air Act requires that NSPS be finalized within a year of proposal, but the
agency received more than 2.6 million public comments—the most ever for a proposed EPA
rule—and it delayed promulgation beyond the statutory deadline. Of particular concern were the
proposed setting of a single standard applicable to both coal-fired and natural gas-fired sources;
the reliance on carbon capture and sequestration (CCS) technology as the means by which coal-
fired plants would comply with the standard; and the cost and technical feasibility of CCS
technology. In general, critics complained that given the cost and unproven nature of CCS, the
NSPS would effectively prohibit the construction of new coal-fired power plants. (For
information on the New Power Plant Carbon Rule, see CRS Report R43127, EPA Standards for
Greenhouse Gas Emissions from New Power Plants.)
9 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, September 15, 2011.
10 The adoption of motor vehicle GHG standards also triggered GHG permit requirements for new stationary sources of
all types. Section 165 of the Clean Air Act requires preconstruction permits and the imposition of best available control
technology for new major sources of all pollutants “subject to regulation” under the act. When the GHG standards for
motor vehicles took effect in January 2011, GHGs became subject to regulation, according to the agency, triggering
Section 165. Thus, GHG permit requirements took effect January 2, 2011.
EPA focused its initial permitting efforts on the largest emitters, granting smaller sources at least a six-year reprieve.
As of January 2014, only 143 GHG permits had been issued by EPA and state permitting authorities. There are as many
as six million stationary sources of GHGs, according to EPA, so the permit requirement has affected a very small
number of sources. Nevertheless, this triggering of standards for the largest new stationary sources (power plants,
manufacturing facilities, and others) raised substantial concern in Congress and among potentially affected industries.
The Supreme Court largely upheld EPA’s GHG permitting authority in Utility Air Regulatory Group v. Environmental
Protection Agency, 134 S. Ct. 2427 (2014).
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On June 25, 2013, the President gave new impetus to EPA’s GHG regulatory efforts. In a major
speech and in a more detailed Climate Action Plan released the same day, the President directed
EPA to re-propose GHG standards for new power plants by September 20, 2013, and finalize
them “in a timely fashion after considering all public comments, as appropriate.”11 More
importantly, he directed the agency to propose GHG emission standards for existing power plants
by June 2014, with promulgation by June 2015.
The emission standards for existing power plants were released June 2, 2014, and appeared in the
Federal Register June 18.12 The proposal would set state-specific goals for CO2 emissions from
fossil-fuel power plants. EPA established different goals for each state based on four “building
blocks”: improved efficiency at coal-fired power plants; substitution of natural gas combined
cycle generation for coal-fired power; zero-emission power generation (from increased renewable
or nuclear power); and demand-side energy efficiency. Two sets of goals were proposed: an
interim set, which would apply to the average emissions rate in a state in the 2020-2029 time
period; and a final state-specific goal for the years 2030 and beyond. In general, states that
currently rely on coal-fired power to a great extent would be allowed higher emission rates, while
those with idle natural gas capacity or state renewable power requirements would need to meet
lower emission rate goals.
Publication of the proposal in the Federal Register began a comment period, which ran through
December 1, 2014. The agency also held four public hearings on the proposal in Atlanta, Denver,
Pittsburgh, and Washington, DC. There are several CRS reports that explore the standards for
existing power plants in more detail.13
Legislative and Judicial Actions
Legislation introduced, but not enacted, in the 112th and 113th Congresses aimed to prevent EPA
from implementing GHG emission requirements. More than a dozen bills were introduced in the
112th, as well as amendments and riders on appropriations bills. The House passed three of these
bills, but the Senate did not follow suit. (For additional detail, see CRS Report R41563, Clean Air
Issues in the 112th Congress.)
Legislation was also considered in the 113th Congress. The House passed H.R. 3826, which would
have prohibited EPA from promulgating or implementing GHG emission standards for fossil-
fueled power plants until at least six power plants representative of the operating characteristics
of electric generation units at different locations across the United States have demonstrated
compliance with proposed emission limits for a continuous period of 12 months on a commercial
basis. Projects demonstrating the feasibility of carbon capture and storage that received
government financial assistance could not have been used in setting such standards, and the
11 Office of the Press Secretary, the White House, “Power Sector Carbon Pollution Standards,” Memorandum for the
Administrator of the Environmental Protection Agency, June 25, 2013, at http://www.whitehouse.gov/the-press-office/
2013/06/25/presidential-memorandum-power-sector-carbon-pollution-standards. See also 78 Federal Register 39535,
July 1, 2013.
12 79 Federal Register 34830, June 18, 2014, at http://www.gpo.gov/fdsys/pkg/FR-2014-06-18/pdf/2014-13726.pdf.
13 See CRS Report R43572, EPA’s Proposed Greenhouse Gas Regulations for Existing Power Plants: Frequently
Asked Questions; CRS Report R43621, EPA’s Proposed Greenhouse Gas Regulations: Implications for the Electric
Power Sector; and CRS Report R43652, State CO2 Emission Rate Goals in EPA’s Proposed Rule for Existing Power
Plants.
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standards would not have taken effect unless Congress enacted new legislation setting an
effective date. The House incorporated the language of H.R. 3826 in H.R. 2, which also passed
the House. Additional bills were introduced to prevent EPA from setting standards for existing
power plants.
Bills in the 114th Congress have taken several forms. The Energy and Commerce Committee has
ordered reported H.R. 2042, which would delay the compliance date of GHG emission standards
for EGUs, and would allow a state to opt out of compliance if the governor determines that the
rule would have an adverse effect on rate-payers or have a significant adverse effect on the
reliability of the state’s electricity system. Other bills would amend the Clean Air Act to remove
EPA authority over greenhouse gases.
Another option with regard to the power plant rules might be resolutions of disapproval under the
Congressional Review Act (CRA). The advantage of a CRA resolution is that it is eligible for
expedited procedures in the Senate: it can reach the Senate floor through a discharge petition
signed by 30 Senators, and once it reaches the floor it cannot be filibustered. If Congress passes a
joint resolution disapproving a rule under procedures provided by the CRA, and the resolution
becomes law,14 the rule cannot take effect or continue in effect. Also, the agency may not reissue
either that rule or any substantially similar one, except under authority of a subsequently enacted
law. (For additional information on the CRA, see CRS In Focus IF10023, The Congressional
Review Act (CRA).)
Another frequently discussed option would be an appropriations rider prohibiting EPA from
finalizing or implementing the EGU standards.
All of these options face the same potential obstacle: President Obama has made the reduction of
GHG emissions one of his major goals; as a result, legislation restricting EPA’s authority to act on
GHG emissions, if passed by Congress, would be likely encounter a presidential veto. Overriding
a veto requires a two-thirds majority in both the House and the Senate. (For additional discussion
of legislative options, see CRS Report R41212, EPA Regulation of Greenhouse Gases:
Congressional Responses and Options.)
EPA’s GHG regulations have been challenged in court, but generally unsuccessfully, to date. On
June 26, 2012, the D.C. Circuit Court of Appeals dismissed challenges to four agency regulations:
the GHG endangerment finding, emission standards for light-duty vehicles, and two rules related
to the permitting of GHG emissions from large stationary sources.15 Subsequently, the Supreme
Court agreed to review one aspect of the D.C. Circuit ruling: “[w]hether EPA permissibly
determined that its regulation of greenhouse gas emissions from new motor vehicles triggered
permitting requirements under the Clean Air Act for stationary sources that emit greenhouse
gases.” In a decision handed down June 23, 2014, the court generally held that EPA’s motor
vehicle GHG standards did trigger permitting requirements for stationary sources, although it put
some limits on the sources that would be required to obtain permits (Utility Air Regulatory Group
v. EPA).16
14 For the resolution to become law, the President must sign it or allow it to become law without his signature, or
Congress must override a presidential veto.
15 Coalition for Responsible Regulation, Inc. v. EPA, 684 F.3d 102 (D.C. Cir. 2012).
16 Utility Air Regulatory Group v. Environmental Protection Agency, 134 S. Ct. 2427 (2014).
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Emissions of Other Pollutants from Power Plants
Issues related to emissions other than GHGs from electric power plants—principally sulfur
dioxide (SO2), nitrogen oxides (NOx), and mercury—have been another focus of interest in
recent years. Two rules affecting these emissions—the Cross-State Air Pollution Rule (CSAPR,
pronounced “Casper”)17 and the Mercury and Air Toxics Standards (MATS)18—have taken effect,
in January and April 2015 respectively. Critics of the rules predicted a “train wreck”19 for the
electric utility industry if these and other rules were implemented. The rules—along with low
natural gas prices—have contributed to the retirement of many older coal-fired power plants, but,
thus far, appear to have had little effect on the price of electricity or the reliability of the electric
system.
Bush Administration regulations addressing these emissions were first promulgated in March
2005, but were vacated and remanded to EPA by the D.C. Circuit Court of Appeals in two 2008
decisions (North Carolina v. EPA20 and New Jersey v. EPA21). As a result, under the Obama
Administration, EPA developed new regulations to address the court’s concerns:
• CSAPR, promulgated on August 8, 2011, established a cap-and-trade system for
SO2 and NOx emissions;
• MATS, promulgated on February 16, 2012, set Maximum Achievable Control
Technology standards for power plant emissions of mercury and other hazardous
air pollutants.
Power plants were major sources of these pollutants before the development of the regulations: in
2005, they accounted for 70% of the U.S. total of SO2 emissions, about half of U.S. mercury
emissions, and roughly 20% of U.S. NOx emissions. 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.
CSAPR: Controlling SO2 and NOx
The CSAPR rule, which is designed to control emissions of air pollution that causes air quality
problems in downwind states, would reduce SO2 emissions from power plants 73%, compared to
2005 levels, and NOx emissions 54%. The rule was controversial when promulgated in 2011, but
the issues now appear largely resolved in EPA’s favor. In the 112th Congress, both the House and
the Senate considered legislation that would have revoked CSAPR. The House passed its version
17 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 was generally referred to as the Clean Air
Transport Rule prior to being finalized.
18 U.S. Environmental Protection Agency, “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,” 77
Federal Register 9304, February 16, 2012.
19 See CRS Report R41914, EPA’s Regulation of Coal-Fired Power: Is a “Train Wreck” Coming?
20 North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008).
21 517 F.3d 574 (D.C. Cir. 2008).
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of the legislation twice, in September 2011 and again in September 2012. The Senate did not take
up either House bill, however. It did consider a resolution of disapproval of CSAPR under the
Congressional Review Act (CRA), but the resolution was rejected by the Senate, 41-56, on
November 10, 2011. (For additional detail, see CRS Report R41563, Clean Air Issues in the 112th
Congress.)
Opponents of CSAPR also challenged the rule in court, where they initially prevailed: the D.C.
Circuit Court of Appeals stayed the rule’s implementation and vacated the rule in August 2012. 22
The Supreme Court overturned the D.C Circuit in April 2014, holding, in a 6-2 decision, that the
plain text of the CAA supported EPA’s decision to impose federal implementation plans for SO2
and NOx on the states, and that the agency’s use of cost-effectiveness to allocate emission
reduction requirements was a reasonable interpretation of its authority under ambiguous statutory
language.23 The Court remanded some issues to the D.C. Circuit for further consideration; but, at
this point, the stay has been lifted and EPA is proceeding to implement the rule. CSAPR’s caps on
SO2 and NOx emissions took effect in January 2015, with a second phase of caps due to be
implemented in 2017.
EPA’s Regulatory Impact Analysis found that CSAPR’s benefits exceed its costs by more than 50-
1. The most important benefit would be 13,000 to 34,000 fewer premature deaths annually,
according to the agency. Avoided deaths and other benefits would occur throughout the East,
Midwest, and South, according to EPA, with Ohio and Pennsylvania benefitting the most.24
Mercury and Air Toxics Standards (MATS)
In 2005, EPA promulgated regulations establishing a cap-and-trade system to limit emissions of
mercury from coal-fired power plants. The rules were challenged, and the D.C. Circuit Court of
Appeals vacated them in 2008 in New Jersey v. EPA.25 Rather than appeal the ruling to the
Supreme Court, EPA agreed to propose and promulgate Maximum Achievable Control
Technology (MACT) standards by the end of 2011. EPA has stated that the standards for existing
units, promulgated February 16, 2012, could be met by 56% of coal- and oil-fired electric
generating units using pollution control equipment already installed. The other 44% would be
required to install technology to reduce uncontrolled mercury and acid gas emissions by about
90%, at an annual cost of $9.6 billion. EPA estimated that the annual benefits of the MATS rule,
including the avoidance of up to 11,000 premature deaths annually, will be between $37 billion
and $90 billion. Existing power plants had until April 2015, with a possible one-year extension, to
meet the standards. About 38% of the plants indicated that they needed the additional time to
comply and, of those, 95% have been granted an extension.26
MATS requires coal-fired power plants to reduce 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
22 EME Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012).
23 EPA v. EME Homer City Generation L.P., 134 S. Ct. 1584 (2014).
24 U.S. EPA, Office of Air and Radiation, “Cross-State Air Pollution Rule,” Overview Presentation, undated, p. 6, at
http://www.epa.gov/crossstaterule/pdfs/CSAPRPresentation.pdf.
25 517 F.3d 574 (D.C. Cir. 2008).
26 National Association of Clean Air Agencies, “Survey on MATS Compliance Extension Requests,” March 17, 2015,
http://www.4cleanair.org/sites/default/files/Documents/MATS_extension_requests_table_March_2015.pdf.
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Clean Air Act Amendments. According to EPA, 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.27 The MATS rule is also
projected to reduce emissions of fine particulates (PM2.5). Although PM2.5 is not listed as a
hazardous air pollutant, EPA believes that the MATS rule’s effect on PM2.5 will lead to the
avoidance of up to 11,000 premature deaths each year.
In its analysis of the MATS rule, the agency concluded that some EGUs would be retired by
2015, rather than invest in control technologies. In all, it said, coal-fired generation capacity
would decline less than 2% as a result of the MATS rule.28 Coal-fired capacity is, of course,
simultaneously being buffeted by market forces, principally the low cost of natural gas, and there
are other proposed or promulgated rules (under the Clean Water Act and the Solid Waste Disposal
Act) that might increase future costs of operation; these could also affect plant retirement
decisions. As a result, more than 2% of coal-fired generation is being retired.
Like the CSAPR rule, the MATS rule has been challenged both in Congress and in the courts. In
the 112th Congress, H.R. 2401 and H.R. 3409 would have declared the MATS rule “of no force
and effect,” would have required that any replacement rule impose the least burdensome
regulatory alternative among those authorized under the Clean Air Act, and would have delayed
compliance with any replacement rule until six years after an interagency panel completed a study
of the cumulative impact of numerous listed EPA rules. Both bills passed the House, but the
Senate did not consider either. It did consider S.J.Res. 37, a resolution to disapprove the MATS
rule under the Congressional Review Act. The resolution was rejected by the Senate, 46-53, on
June 20, 2012.
The regulations were also challenged in the D.C. Circuit Court of Appeals (White Stallion Energy
Center v. EPA). Petitioners focused on EPA’s finding that mercury controls for electric power
plants were “appropriate and necessary,” a prerequisite to regulation under Section 112(n) of the
Clean Air Act. Petitioners argued that the agency found few direct benefits from controlling
mercury or other air toxics. The vast majority of the monetized benefits in EPA’s analysis would
come from reduced emissions of PM2.5, which the pollution control equipment would achieve as a
co-benefit. Plaintiffs also argued that EPA had a duty to consider cost in determining whether the
standards were appropriate and necessary, and did not do so.
The D.C. Circuit disagreed. In a 2-1 decision handed down April 15, 2014, the court found that
the statute offers no express guidance regarding what factors EPA was to consider in deciding
whether regulation was “appropriate and necessary,” nor does it define the words. Where the
statute is silent, the court followed the precedent set in the 1984 Supreme Court case, Chevron
USA, Inc. v. Natural Resources Defense Council, upholding the agency’s interpretation so long as
it constitutes “a permissible construction of the statute.”29 The D.C. Circuit decision was appealed
to the Supreme Court, which has agreed to hear the case (now styled Michigan v. EPA30). Oral
27 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.
28 U.S. EPA, Regulatory Impact Analysis for the Final Mercury and Air Toxics Standards, pp. 3-14 to 3-20, at
http://www.epa.gov/ttn/ecas/regdata/RIAs/matsriafinal.pdf.
29 White Stallion Energy Center v. EPA, 748 F.3d 1222, 1234-1236 (D.C. Cir. 2014).
30 U.S., No. 14-46, cert. granted 11/25/14.
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argument took place on March 25, 2015. A decision is expected before the end of the Court’s
current term.
For additional information on the CSAPR and MATS rules, see CRS Report R42895, Clean Air
Issues in the 113th Congress: An Overview.
Air Quality Standards
The Obama Administration’s EPA has reviewed several national ambient air quality standards
(NAAQS), as it is required to do at five-year intervals by Section 109 of the Clean Air Act.
NAAQS do not directly regulate emissions from sources of pollution; rather, they 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 can lead to
designation of “nonattainment areas” and the imposition of emission controls.
Background
Air quality has improved substantially since the passage of the Clean Air Act in 1970. Annual
emissions of the six air pollutants for which EPA has set ambient air quality standards (ozone,
particulate matter, sulfur dioxide, carbon monoxide, nitrogen dioxide, and lead) have declined by
72%, despite major increases in population, motor vehicle miles traveled, and economic
activity.31 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 these 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 air quality problems involve ozone and fine particles. A recent study by
researchers at the Massachusetts Institute of Technology concluded that emissions of particulate
matter and ozone caused 210,000 premature deaths in the United States in 2005.32 Many other
studies have found links between air pollution, illness, and premature mortality, as well. EPA
summarizes these studies in what are called Integrated Science Assessments and Risk Analyses
when it reviews a NAAQS, and it identifies areas where concentrations of pollution exceed the
NAAQS following its promulgation. As of January 2015, 123 million people lived in areas
classified as “nonattainment” for the current ozone NAAQS (Figure 1); 42 million lived in areas
that were nonattainment for the fine particle (PM2.5) NAAQS.33
31 For additional data on air pollution trends, see http://www.epa.gov/airtrends/aqtrends.html#comparison.
32 Fabio Caiazzo et al., “Air Pollution and Early Deaths in the United States. Part I: Quantifying the Impact of Major
Sectors in 2005,” Atmospheric Environment, November 2013, pp. 198-208.
33 Data for ozone nonattainment areas are from the U.S. EPA “Green Book,” at http://www.epa.gov/airquality/greenbk/
hntc.html. Data for PM2.5 nonattainment areas are also from the “Green Book,” at http://www.epa.gov/airquality/
greenbk/rntc.html.
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Figure 1. Ozone Nonattainment Areas (2008 Standard, 0.075 ppm)
Source: U.S. EPA Green Book, http://www.epa.gov/airquality/greenbk/map8hr_2008.html. Map shows areas
designated nonattainment by EPA as of July 2, 2014.
Violations of the ambient air quality standards for the other four criteria pollutants are not as
widespread, but EPA is engaged in (or has recently completed) reviews indicating that health
effects of most of these pollutants are more serious and more prevalent than previously thought.
As recently as 2010, for example, no areas exceeded the NAAQS for sulfur dioxide (SO2), but in
a review concluded that year, EPA determined that between 2,300 and 5,900 premature deaths
could be avoided annually by strengthening that standard.34 The agency now concludes that 1.9
million people live in areas that are nonattainment for a revised SO2 NAAQS.35 A review of the
lead standard completed in 2008 concluded that it should be lowered by 90%,36 as a result of
which nearly 10 million people are considered to live in areas with unhealthy levels of
atmospheric lead.37
CRS Report R41563, Clean Air Issues in the 112th Congress, summarized 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
34 U.S. EPA, “Revisions to the Primary National Ambient Air Quality Standard, Monitoring Network and Data
Reporting Requirements for Sulfur Dioxide (SO2),” Text Slides, June 2010, p. 21, at http://www.epa.gov/air/
sulfurdioxide/pdfs/20100603presentation.pdf.
35 http://www.epa.gov/airquality/greenbook/tntc.html.
36 U.S. EPA, “Fact Sheet, Final Revisions to the National Ambient Air Quality Standards for Lead,” 2008, at
http://www.epa.gov/air/sulfurdioxide/pdfs/20100603presentation.pdf. A more recent review, released December 19,
2014, has proposed that the 2008 NAAQS should be retained. See http://www.epa.gov/air/lead/actions.html#dec2014.
37 U.S. EPA, Green Book, at http://www.epa.gov/oaqps001/greenbk/popexp.html.
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been completed since 2006, with the standards being made more stringent for five of the six. The
next round of reviews has begun for each of the pollutants.
Reviews do not always lead to revision of the standards. In August 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. The current review of the lead
NAAQS, similarly, has resulted in a proposal to retain the standard set in 2008.38
The Ozone NAAQS
Since 2010, review of the NAAQS for ozone has sparked recurrent controversy. In January 2010,
EPA proposed a revision to the ozone NAAQS.39 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 EPA suspended implementation of the new standard in
September 2009 in order to consider further strengthening it, and proposed a more stringent
standard in January 2010.
On September 2, 2011, however, with a final rule in the last steps of interagency review at the
Office of Management and Budget (OMB), the White House announced that the President had
requested that EPA Administrator Jackson withdraw the all-but-final (more stringent) 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.”40 (For
discussion of the 2010-2011 reconsideration, see CRS Report R42895, Clean Air Issues in the
113th Congress: An Overview.)
EPA’s December 2014 Proposal
Since then, EPA has proceeded with the statutorily required five-year review of the 2008
standard, as the President indicated the agency would. The agency missed the statutory five-year
deadline for completion of the review in March 2013, and a federal district court subsequently
ordered the agency to propose any revisions resulting from this review by December 1, 2014, and
to release a final decision by October 1, 2015. The agency’s proposal was released on November
26, 2014, and appeared in the Federal Register on December 17.41
The proposal would set more stringent standards, lowering both the primary (health-based) and
secondary (welfare-based) standards from the current 75 parts per billion (ppb) to somewhere in a
range of 65 to 70 ppb. EPA maintains that most areas will be able to reach attainment of the new
38 http://www.epa.gov/air/lead/actions.html#dec2014.
39 U.S. Environmental Protection Agency, “National Ambient Air Quality Standards for Ozone; Proposed Rule,” 75
Federal Register 2938, January 19, 2010.
40 The White House, Office of the Press Secretary, “Statement by the President on the Ozone National Ambient Air
Quality Standards,” September 2, 2011.
41 79 Federal Register 75234, available at http://www.gpo.gov/fdsys/pkg/FR-2014-12-17/pdf/2014-28674.pdf. For
links to EPA’s fact sheets and technical documents, see http://www.epa.gov/air/ozonepollution/actions.html.
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standards—whether at 65 or 70 ppb—as a result of already promulgated regulations for gasoline,
autos, power plants, and other sources of emissions. If current monitoring data were used to
designate nonattainment areas, EPA states that 358-558 counties outside California would have
monitors showing nonattainment. The agency’s modeling shows all but nine of these counties
reaching attainment with a 70 ppb standard by 2025 as a result of the already promulgated
standards (for power plants, motor vehicles, gasoline, and other sources), and all but 68 attaining
a 65 ppb standard through the same measures.
Thus, the agency’s estimates of the cost of attaining a revised ozone NAAQS are substantially
lower than many earlier estimates. EPA estimates the cost of meeting a 70 ppb standard in all
states except California at $3.9 billion annually in 2025; the cost of meeting a 65 ppb standard in
the same states is estimated at $15 billion annually. Because most areas in California would have
until the 2030s to reach attainment,42 EPA provided separate cost estimates for California ($0.80
billion to $1.6 billion annually in 2038). EPA’s cost estimates are substantially less than one from
the National Association of Manufacturers that was widely circulated before the release of EPA’s
proposal, and has been updated since the agency’s proposal.43
Members of Congress have shown particular interest in whether the expected benefits of the
proposed standards would justify their costs. Both nationwide and in California, the agency
expects the benefits of attainment to exceed the costs, but there is controversy over the methods
used to estimate both. Also, although the agency prepares cost and benefit estimates at the time it
proposes or promulgates a NAAQS—for information purposes and compliance with Executive
Order 12866, under which the OMB requires cost-benefit analysis of economically significant
rules—as the Clean Air Act is currently written, the agency is prohibited from weighing costs
against benefits in setting the standards.
The Clean Air Act’s Section 109 has been interpreted to prohibit consideration of costs in the
setting of NAAQS since the provision was added to the act in 1970. In 2001, this interpretation
was affirmed in a unanimous Supreme Court decision, Whitman v. American Trucking
Associations.44 Section 109 simply states that the EPA Administrator is to set the primary standard
at a level requisite to protect public health, allowing an adequate margin of safety. The Court
pointed to numerous other CAA sections where Congress had explicitly allowed consideration of
economic factors, concluding that if Congress had intended to allow such factors in the setting of
a primary NAAQS, it would have been more forthright—particularly given the centrality of the
NAAQS concept to the CAA’s regulatory scheme. The court concluded that Section109(b)(1)
“unambiguously bars cost considerations from the NAAQS-setting process.”45
This is not to say that cost considerations play no role in Clean Air Act decisions, including in
implementation of a NAAQS. Cost-effectiveness is considered extensively by EPA and the states
in selecting emission control options to meet the standards. But in deciding what level of ambient
pollution poses a health threat, the statute bars consideration of costs.
42 Under the statute, areas with more severe ozone pollution are given additional time to reach attainment of the
standard, and must impose additional emission controls.
43 NERA Economic Consulting for the National Association of Manufacturers, Economic Impacts of a 65 ppb National
Ambient Air Quality Standard for Ozone, February 2015, at http://www.nam.org/Special/Media-Campaign/EPA-
Overregulation/Ozone-Regulations.aspx.
44 531 U.S. 457 (2001).
45 For further discussion of the American Trucking case, see CRS Report RS20860, The Supreme Court Upholds EPA
Standard- Setting Under the Clean Air Act: Whitman v. American Trucking Ass'ns.
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Congress is likely to take a keen interest in the results of the current review as it nears
completion. As of early May, four proposals had been introduced in the 114th Congress that would
modify EPA’s authority or prohibit or delay the agency’s proposed strengthening of the ozone
standard:
• H.R. 1044 would require each state to revise the boundaries of ozone and carbon
monoxide nonattainment areas that include entire metropolitan or consolidated
metropolitan statistical areas, to exclude counties that are not in violation of the
NAAQS, as determined by air quality monitoring;
• H.R. 1327 / S. 640 would delay the review and revision of the ozone NAAQS for
three years and require future reviews at 10-year rather than 5-year intervals;
• H.R. 1388 / S. 751 would prohibit a more stringent standard until at least 85% of
the counties in nonattainment areas as of July 2, 2014, attained the current
standard, and would require EPA to consider feasibility and cost in setting an
ozone NAAQS, among other provisions; and
• H.R. 2111 would provide that no funds made available under any act may be
used by EPA to implement any ozone standard promulgated after its date of
enactment.
For additional information on revision of the ozone NAAQS, see CRS Report R43092, Ozone Air
Quality Standards: EPA’s 2015 Revision.
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. Numerous bills that would have overturned specific regulations or limited the agency’s
authority were introduced, and some passed the House in the 112th and 113th Congresses. With
Republicans controlling the Senate as well as the House in the 114th Congress, similar bills are
being considered.
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.46
Environmental and public health 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, do not 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
46 See, for example, U.S. EPA, Office of Air and Radiation, “The Clean Air Act and the Economy,” August 15, 2013,
at http://www.epa.gov/cleanairactbenefits/economy.html.
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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.
The courts will continue to play an important role, and Congress may react to court decisions
regarding Clean Air Act regulation through legislation. But given the importance placed on clean
air and climate by the Obama Administration, the principal challenge facing opponents in
Congress may be whether they can muster the votes to overcome presidential vetoes.47
Author Contact Information
James E. McCarthy
Specialist in Environmental Policy
jmccarthy@crs.loc.gov, 7-7225
47 For additional discussion of EPA’s regulatory actions under all the environmental statutes, see CRS Report R41561,
EPA Regulations: Too Much, Too Little, or On Track?
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