Order Code RL31881
CRS Report for Congress
Received through the CRS Web
Mercury Emissions to the Air:
Regulatory and Legislative Proposals
Updated May 26, 2004
James E. McCarthy
Specialist in Environmental Policy
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

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Mercury Emissions to the Air:
Regulatory and Legislative Proposals
Summary
On December 15, 2003, the Environmental Protection Agency (EPA) proposed
standards for emissions of mercury from coal-fired electric power plants, under the
authority of Sections 111 and 112 of the Clean Air Act. (The proposal appeared in
the Federal Register January 30, 2004.) In their first phase, the standards could
require a 29% reduction in emissions by 2008 or 2010, depending on the regulatory
option chosen. A nearly 70% reduction would take effect in 2018, although EPA
indicates that flexibility built into the proposed standards could delay the full 70%
reduction to as late as 2030.
EPA’s analysis of the proposed rule indicates that its benefits would outweigh
the compliance costs by a factor of at least 16 to 1, leading many critics of the
proposal to ask why the regulations should not be more stringent, or implemented
more quickly. The Agency’s official position is that technology will not be available
to achieve reductions greater than 30% until after 2010. EPA’s own Office of
Research and Development (ORD) appears to disagree, however. A recent ORD
white paper found that reductions of 72% - 98%, depending on coal type, are already
being achieved at some plants using current technology. Other issues likely to be
raised in the public comment period, which extends until June 29, include the
impacts on eastern coal production and the effect of the proposals on mercury “hot
spots.”
In addition to EPA’s regulatory effort, in the current Congress nine bills have
been introduced to regulate these emissions. An Administration bill, the “Clear Skies
Act,” has many points in common with the EPA regulatory proposal. The other bills
before Congress are generally more stringent than the Administration’s approach.
These regulatory and legislative proposals reflect increasing concern over the
potential health effects of mercury emissions. Mercury is a potent neurotoxin that
can affect human health at very low concentrations. EPA considers children born to
women with umbilical cord blood-mercury concentrations above 5.8 parts per billion
to be at increased risk for adverse health effects, such as delayed development,
neurological defects, and mental retardation. Recent EPA studies conclude that at
least 7.8% (and possibly as many as 15.7%) of American women of child-bearing age
have blood mercury levels above this threshold.
U.S. air emissions of mercury come from eight principal sources. Of these, the
largest source, and the last major source for which emission standards have been
proposed, is coal-fired electric power plants. Coal-fired power plants account for
between one-third and one-half of total U.S. mercury emissions.
This report provides background on mercury and reviews regulatory and
legislative proposals to reduce emissions of mercury to the air. CRS Report
RL32203 and CRS Report RL31908 discuss legal issues raised by EPA’s proposed
rules and mercury in products and waste, respectively. This report will be updated
as warranted.

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Contents
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Sources of Emissions / Status of Regulations . . . . . . . . . . . . . . . . . . . . . . . . 2
Regulation of Non-Utility Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Electric Utilities and Mercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
EPA’s December 15 Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
What the Standards Would Achieve . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Residual Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Costs and Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Should the Standards Be More Stringent? . . . . . . . . . . . . . . . . . . . . . . . 9
Hot Spots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Effects on Eastern and Western Coal . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Legislation in the 108th Congress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
List of Tables
Table 1. Mercury (Hg) Emissions Estimates and Current Regulatory Status . . . . 3
Table 2. Mercury Emission Standards Under the Proposed Utility
MACT Rule (in 10-6 lb/MWh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 3. Estimated Emission Reductions and Cost of Proposed Utility
MACT Rule, by Coal Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 4. Estimated Changes in Coal Use from Imposition of the Proposed
Utility MACT Rule, 2000-2010, by Region . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 5. Comparison of Mercury Emission Legislation . . . . . . . . . . . . . . . . . . . 20

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Mercury Emissions to the Air: Regulatory
and Legislative Proposals
Background
Mercury is a potent neurotoxin that can cause adverse health effects at very low
concentrations. Concerns about public exposure to mercury have grown in recent
years as research has indicated its presence at significant levels in numerous species
of fish, and as analyses of dietary intake and resulting blood levels have pointed to
potential health risks from mercury ingestion, particularly for women of child-bearing
age and developing fetuses.
According to the Environmental Protection Agency (EPA), as of December
2002, 45 states had issued fish consumption advisories due to mercury. Eighteen
states (primarily in the Midwest and Northeast) have issued statewide advisories for
mercury in all their freshwater lakes and/or rivers. Ten states, primarily in the South,
have statewide advisories for mercury in their coastal waters. In all, the advisories
cover more than 12 million acres of lakes and roughly 473,000 river miles.1
Mercury reaches water bodies from naturally occurring sources, from past uses
(many of which, such as fungicide application to crops, are now banned), from
disposal of mercury-containing products, and from current activities (principally
combustion of fuels containing mercury in trace amounts). Mercury released to the
atmosphere can circulate for up to a year before being deposited on land or in water.
Thus, it is widely dispersed, and often is transported thousands of miles from the
sources of emissions.2 According to EPA, U.S. sources contributed only 3% of the
5,500 tons of mercury emitted to the atmosphere on a global basis in 1995.3 Of the
mercury deposited in the United States, however, about 60% comes from U.S.
sources.4
1 U.S. EPA, Office of Water, “Update: National Listing of Fish and Wildlife Advisories,”
Fact Sheet, May 2003, pp. 4-5, available at
[http://www.epa.gov/waterscience/fish/advisories/factsheet.pdf].
2 U.S. EPA, Office of Air Quality Planning and Standards, 1997 Mercury Study Report to
Congress: Overview, December 1997, p. 1, available at
[http://www.epa.gov/ttn/atw/112nmerc/mercover.html].
3 Ibid.
4 U.S. EPA, Office of Air and Radiation, Mercury White Paper, p. 1, available at
[http://www.epa.gov/ttn/oarpg/t3/memoranda/whtpaper.pdf].

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CRS-2
Because mercury emissions are concentrated in specific areas, and because of
variations in precipitation patterns, mercury is not deposited evenly across the United
States. The highest deposition rates, according to EPA, “occur in the southern Great
Lakes, the Ohio Valley, the Northeast, and scattered areas in the Southeast.”5
Of particular concern for aquatic organisms and human health is mercury in the
form of methyl mercury. Nearly all of the mercury that accumulates in fish tissue is
methyl mercury, an organic compound formed by a microbial process, often in
wetland environments. Once formed, methyl mercury tends to bio-accumulate in
aquatic organisms, increasing concentrations at each level of the food chain. “As a
result, top predators in a food chain, such as largemouth bass or walleye, may have
concentrations of these chemicals in their tissues that may be a million times higher
than the concentrations in the water.”6
Children born to women with fetal cord blood concentrations of mercury above
5.8 parts per billion (ppb) “are at some increased risk of adverse health effects,”7
according to EPA. These health effects include delayed development, neurological
defects, and mental retardation. Recent EPA analyses conclude that at least 7.8%
(and possibly as many as 15.7%) of women of child-bearing age had blood-mercury
levels high enough that their umbilical cord blood would have been above the 5.8
ppb threshold in 1999-2000.8
Sources of Emissions / Status of Regulations
As shown in Table 1, U.S. air emissions of mercury come from eight principal
sources. Of these, the largest source, and the last source for which emission standards
have been proposed or implemented, is coal-fired utility boilers (i.e., coal-fired
electric power plants). These accounted for an estimated 52 tons of mercury
emissions per year in 1994-1995, about one-third of total U.S. mercury emissions at
the time.9
Regulation of Non-Utility Sources. As of December 2003, EPA had
proposed or promulgated regulations for all major sources of mercury emissions.
5 Ibid.
6 National Listing of Fish and Wildlife Advisories, previously cited, p. 5.
7 U.S. EPA, Office of Children’s Health Protection, America’s Children and the
Environment: Measures of Contaminants, Body Burdens, and Illnesses, 2nd edition, February
2003, available at [http://www.epa.gov/envirohealth/children/ace_2003.pdf], p. 59.
8 Kathryn R. Mahaffey, “Methylmercury: Epidemiology Update,”, presented at U.S. EPA
National Forum on Contaminants in Fish, San Diego, CA, January 26, 2004, p. 5. Available
at [http://www.epa.gov/waterscience/fish/forum/2004/presentations/monday/mahaffey.pdf].
9 EPA does not have current data for all sources of mercury emissions. Since the mid-
1990s, mercury emissions have been reduced substantially from the three waste
combustor/incinerator categories, and marginally from electric utilities. In its regulatory
impact analysis for the proposed electric utility rule, EPA used 1999 data showing utility
emissions of 48 tons as the baseline against which to compare reductions.

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Table 1. Mercury (Hg) Emissions Estimates
and Current Regulatory Status
Source
Emissions
Percentage
Current Status of Hg Regulations
(tons/year)
of Total
Coal-fired Utility
52
33%
12/15/03 proposal would reduce
Boilers
emissions 69% (to 15 tons) by 2018,
or 29% (to 34 tons) in 2007.
Large (>250 tons per
30
19%
Regulated: reductions estimated at
day) Municipal Waste
about 95% from 1990 levels.
Combustors (MWC)
Coal-fired Commercial/
21
13%
Rule proposed 1/13/03 would
Industrial Boilers
reduce emissions about 30%.
Medical Waste
16
10%
Regulated: reductions estimated at
Incinerators
about 94% from 1990 levels, mostly
through closures.
Oil-fired Commercial/
8
5%
Rule proposed 1/13/03 would
Industrial Boilers
reduce emissions about 30%.
Mercury Cell Chlor-
7**
4%
Rule promulgated 12/19/03 will
alkali Plants
reduce emissions 73% by 12/19/06.
Hazardous Waste
7
4%
Regulated: reductions estimated at
Combustors
about 50% from 1990 levels.
Portland Cement Plants
5
3%
Rule, promulgated 6/14/99, reduces
hazardous air pollutant metal
emissions 24%; remanded by U.S.
Court of Appeals, D.C. Circuit to
require specific standard for mercury
and 2 other pollutants.
TOTAL*
146 of 158
92%
*Emissions estimates are for 1994-1995. Totals may not add due to rounding. Other sources
include residential boilers (4 tons); other manufacturing, including pulp and paper manufacturing
and 9 other industries (4 tons); area sources, such as lamp breakage, lab use, and dental preparations
(3.4 tons); and geothermal power (1.4 tons).
** Data for the chlor-alkali sector are subject to considerable uncertainty. Chlor-alkali plants
produce chlorine by subjecting liquid mercury and saturated brine to an electric current. The
mercury binds with potassium or sodium in the process, but later is separated and reused. In the
year 2000, 65 tons of mercury that the plants consumed could not be accounted for.
Sources: Emissions data from U.S. EPA, Mercury Study: Report to Congress, Volume II. RPS-
452/R-97-004 (December 1997), p. ES-6; regulatory status from EPA, Mercury White Paper (not
dated), with information updated by telephone communications with EPA.

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The authority for most of these regulations is Section 112 of the Clean Air Act,
which requires National Emission Standards for Hazardous Air Pollutants. In
amending Section 112 in 1990, Congress included a list of 188 hazardous air
pollutants to be regulated – mercury among them. EPA was directed to identify
sources of these pollutants and impose Maximum Achievable Control Technology
(MACT). Sources of mercury emissions, including coal- and oil- fired commercial
and industrial boilers, chlor-alkali plants, and Portland cement plants, have
regulations either proposed or promulgated under this authority.
Separately, Section 129 of the Clean Air Act requires emission standards for
solid waste incinerator units, including municipal and medical waste incinerators.
These standards, which were promulgated in the mid-1990s, limit 11 categories of
pollutants, including mercury. Under the standards, municipal and medical waste
incinerators, which together accounted for 29% of total U.S. mercury emissions
before regulation, have achieved emission reductions of 95%, and together emitted
only 2.2 tons of mercury in 2000, according to EPA.10 As a result, coal-fired utilities
may now account for nearly half of U.S. mercury emissions.11
Electric Utilities and Mercury
Electric utilities were singled out for special consideration by the 1990 Clean
Air Act Amendments. Under Section 112(n), EPA was required to undertake two
studies of mercury emissions and other hazardous air pollutants from electric utility
steam generating units, and to report to Congress before deciding whether to impose
MACT standards. One study was to characterize emissions from utilities, municipal
waste incinerators, and other sources, determine their health and environmental
effects, identify the technologies available to control emissions, and estimate the
costs of such technologies. The other study was to determine the hazards to public
health anticipated as a result of emissions of all hazardous air pollutants emitted by
electric utilities after imposition of other requirements of the act, and describe
“alternative control strategies for emissions which may warrant regulation under this
section.” After considering the results of this study, “the Administrator shall regulate
electric utility steam generating units under this section [Section 112], if the
Administrator finds such regulation is appropriate and necessary....”
Having submitted the required reports to Congress under this section in 1997
and 1998,12 EPA Administrator Carol Browner did find such regulation appropriate
10 “Major Reductions in Toxics, Metals Seen from Controls on Incinerators, EPA Says,”
Daily Environment Report, June 25, 2002, p. A-3.
11 In the TRI database, electric utilities accounted for 60.6% of total air emissions of
mercury and mercury compounds in 2001. The database somewhat overstates the utility
share of the total because it excludes waste incineration and all sources that emit less than
10 pounds of mercury.
12 U.S. EPA, Office of Air Quality Planning and Standards, Study of Hazardous Air
Pollutant Emissions from Electric Utility Steam Generating Units – Final Report to
C o n g r e s s , F e b r u a r y 1 9 9 8 , 2 v o l u m e s , a v a i l a b l e a t
[http://www.epa.gov/ttn/atw/combust/utiltox/utoxpg.html#TEC] and U.S. EPA, OAQPS and
(continued...)

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and necessary, and issued a formal finding to that effect in December 2000.13 The
finding set in motion the development of MACT standards. The standards were to
be proposed by December 15, 2003 (a deadline EPA met). A final MACT rule must
be signed by March 15, 2005, with compliance for existing facilities required three
years after promulgation.14
Section 112 defines MACT for new facilities as an emission standard no less
stringent than what is achieved in practice by the best controlled similar source (i.e.,
the best demonstrated technology). For existing facilities, it allows a somewhat less
stringent standard, setting the average emissions of the best performing 12% of units
in the category as a minimum, but giving EPA discretion to set a more stringent
standard. While there is considerable disagreement regarding the level of emissions
reduction being achieved (a point discussed below on p. 9, under the heading,
“Should the Standards Be More Stringent?”), at present no U.S. coal-fired power
plants have installed equipment specifically intended to control mercury emissions.
Four full-scale field tests of a technology called “activated carbon injection” (ACI)
have been conducted by the Department of Energy, with emission reductions of 60%
to 90% achieved, depending on the type of coal and type of auxiliary control
equipment utilized.15 ACI has also shown itself capable of reducing mercury
emissions by more than 90% on incinerators and other facilities. Thus, the
technologies appear promising, but the limited number of demonstrations on
operating full-scale coal-fired power plants may give EPA considerable latitude to
choose what will be the MACT standard for the utility sector.
EPA’s December 15 Proposal. In its December 15, 2003 proposal (which
appeared in the Federal Register January 30, 2004), EPA offered two alternative
regulatory approaches to controlling electric utility emissions. In one proposed
approach, regulation of electric utilities under §112(d) of the Clean Air Act is held
to be “appropriate and necessary,” as it was in the Agency’s December 2000
Regulatory Finding, and a MACT standard (which would likely take effect in 2008)
is proposed.
In the other approach, the Agency argues that regulation of electric utilities
under Section 112 is “appropriate,” but is not “necessary” because the Agency could
12 (...continued)
Office of Research and Development, Mercury Study Report to Congress, December 1997,
8 volumes, available at [http://www.epa.gov/airprogm/oar/mercury.html].
13 Regulatory Finding on the Emissions of Hazardous Air Pollutants from Electric Utility
Steam Generating Units, 65 Federal Register 79825, December 20, 2000.
14 These dates are fixed in a modified settlement agreement filed November 17, 1998. The
case is Natural Resources Defense Council, Inc. v. U.S. EPA, No. 92-1415 (D.C. Cir.).
Originally, the deadline for promulgation was December 15, 2004. In late April 2004,
NRDC offered to extend the deadline 90 days in order to allow for additional analysis of
regulatory options. EPA accepted the offer.
15 See Michael D. Durham, ADA Environmental Solutions, “Results from Four Full-Scale
Field Tests of ACI for Control of Mercury Emissions,” presentation to U.S. EPA’s Utility
M A C T W o r k i n g G r o u p , M a r c h 4 , 2 0 0 3 , p . 2 9 , a v a i l a b l e a t
[http://www.epa.gov/ttn/atw/combust/utiltox/adamact.pdf]

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use another section of the Clean Air Act to control the emissions. In this alternative,
it proposes to amend its December 2000 Regulatory Finding, freeing itself from the
requirement to impose MACT standards. Instead, it would use a less prescriptive
approach to regulation known as “cap and trade,” under Section 111 of the act.16 The
legality of this approach is almost certain to be challenged in court. (For a discussion
of the legal issues, see CRS Report RL32203, Legal Analysis and Background on the
EPA’s Proposed Rules for Regulating Mercury Emissions from Electric Utilities.)
The alternative proposal (which EPA prefers) would establish national and state
rather than facility-specific caps on emissions of mercury, and would allow electric
generating facilities to comply either by installing pollution controls or by purchasing
emission credits from other facilities that may have reduced pollution by more than
the required amount. This cap and trade proposal mirrors the approach used to
control emissions of sulfur dioxide (SO ) from power plants under Title IV of the
2
Clean Air Act (the acid rain program). It also mirrors, in key respects, the
Administration’s proposed mercury control program under its Clear Skies bill (S. 485
/ H.R. 999, and more closely, a revised version of the bill introduced by Senator
Inhofe, S. 1844).17 States would be free to establish more stringent standards for new
or existing units than are required under the proposal.
New facilities, in addition to existing facilities, would be covered under the
mercury cap and would be required to purchase allowances equivalent to their
emissions. The Agency notes that this is an advantage of the cap and trade approach:
the total amount of allowed emissions will not increase, even if there is a substantial
increase in coal-fired capacity. Under a MACT standard (which is specific to
individual plants), if coal-fired capacity increases, total emissions would increase
proportionately. DOE projects a 26% increase in coal consumption by 2020. If this
occurs without a further strengthening of the standards, MACT would permit
emissions of 43 tons of mercury in 2020.
Section 111(d), on which the Agency is relying for the cap and trade proposal’s
legislative authority, has rarely been used until now, and has never been used to
regulate a hazardous air pollutant listed under Section 112. EPA staff say that it has
previously been used to regulate sulfur emissions from pulp and paper mills and
16 Neither Section 111 nor Section 112 actually mention cap and trade programs. Section
111 requires “standards of performance,” defined as a standard that “reflects the degree of
emission limitation achievable through the application of the best system of emission
reduction [emphasis added] which ... the Administrator determines has been adequately
demonstrated.” EPA argues that this language would allow a cap and trade system. Section
112(d) also uses broad language, referring to “measures, processes, methods, systems, or
techniques,” but in elaborating on this definition for nearly a page, the statute provides
numerous examples and specifics, without once mentioning cap and trade systems.
Arguably that makes it more difficult to use its language to justify a cap and trade approach.
17 Clear Skies’ cap and trade proposal is also mirrored in another regulatory proposal
published in the Federal Register the same day as the mercury proposal, the Interstate Air
Quality Rule, leading some to conclude that the Agency intends to implement major
elements of Clear Skies through regulation if it cannot do so through legislation. For further
information, see CRS Report RL32273, Air Quality: EPA's Proposed Interstate Air Quality
Rule.

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CRS-7
fluoride emissions from aluminum smelters, neither of which are controlled
elsewhere in the act. While it is potentially more flexible, the initial deadline for
implementation by existing sources is two years later than under MACT, and,
because of the paucity of nondiscretionary deadlines in Section 111(d), court
challenges to Agency action (or inaction) may also take longer than under Section
112. On the other hand, the Section 111(d) proposal would establish a second phase
of regulation, with more stringent requirements; any more stringent standards under
Section 112 would require a new rule-making, a less certain prospect.
What the Standards Would Achieve. If implemented as proposed, the
MACT standards for coal-fired power plants would result in emissions of 34 tons of
mercury annually, a reduction of 29% from the 1999 level. This estimate somewhat
overstates the impact of the proposed regulation, because emissions of mercury from
electric utilities are declining even in the absence of MACT.
Two factors are contributing to this decline. First, pollution controls for sulfur
dioxide and nitrogen oxides required under other sections of the Clean Air Act have
reduced mercury emissions over the last decade. EPA expects this trend to continue.
Under its proposed Interstate Air Quality Rule, projected mercury emissions would
decrease to 34 tons by 2010 without any controls specifically designed to reduce
mercury emissions being imposed.18
Second, state standards are beginning to target mercury from power plants. At
least five states (Connecticut, Massachusetts, Wisconsin, North Carolina, and New
Jersey) have proposed or promulgated standards that will reduce mercury emissions
from power plants by 60% to 95%. Other states are expected to follow suit,
particularly if EPA’s national standards do not impose what the states consider
sufficiently stringent requirements.
The cap and trade program that EPA is proposing under Section 111 would
require more stringent controls, but not until 2018. The proposal would be
implemented in two phases. The first phase, effective in 2010 would impose a cap,
the amount of which is yet to be determined. Early drafts of the regulation set this
cap at 34 tons, but the proposal discusses several possibilities and asks for comments
on what the level should be. The second phase would set a 15 ton cap in 2018 (a
69% reduction from 1999 levels).
Under the cap and trade proposal, existing sources would earn credits for
emission reductions achieved prior to the effective dates, which means that some
reductions would likely be achieved sooner than required. To the extent that early
reductions happen, however, some of the credits they generate may be used in lieu
of reductions required at later dates. This would delay the date on which full
compliance would be achieved.
18 U.S. EPA, Proposed National Emission Standards for Hazardous Air Pollutants; and,
in the Alternative, Proposed Standards of Performance for New and Existing Stationary
Sources: Electric Utility Steam Generating Units (hereafter, the Mercury Proposal),
Preamble, Table 9, 69 Federal Register 4712, January 30, 2004.

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Residual Risks. The MACT proposal does not have a second phase, but if
MACT standards are promulgated, Section 112(f) of the act would require the
Administrator to consider imposing “residual risk” standards. Under Section 112(f),
the Administrator must promulgate such standards eight years after the promulgation
of MACT (December 2012, in this case) if they “are required in order to provide an
ample margin of safety to protect public health ... or to prevent ... an adverse
environmental effect.” To date, EPA has not used this authority for any category of
sources, however.
Costs and Benefits.
EPA estimates the annualized cost of compliance
with the 34-ton electric utility MACT at $945 million. Adding in additional costs to
consumers of affected products raises the annual “social costs” to an estimated $1.6
billion. Quantifiable benefits are estimated at more than $15 billion annually (about
16 times the compliance cost, or more than 9 times the social costs).
The quantified benefits all result from the controls’ effect on emissions of fine
particulates (PM ), which are a cobenefit of the mercury controls, rather than the
2.5
effects of controlling mercury itself. The reductions in PM would avoid 2,200
2.5
premature deaths annually, 2,900 non-fatal heart attacks, thousands of hospital and
emergency room visits, and millions of work loss and restricted activity days,
according to EPA.19
EPA’s analysis lists 11 health and welfare benefits of controlling mercury itself
(i.e., effects separate from those attributable to the side effects from reducing PM ).
2.5
These include reductions in neurological disorders, learning disabilities, and
developmental delays; impacts on birds and mammals, such as reproductive effects;
impacts on commercial, subsistence, and recreational fishing; and reduced “existence
values” for currently healthy ecosystems. It also lists as potential mercury control
benefits reductions in cardiovascular effects, altered blood pressure regulation, and
reproductive effects in humans. None of these benefits are quantified, but the
Agency believes that they “are large enough to justify substantial investment in Hg
emission reductions.”20
EPA does not estimate the costs of compliance with the Section 111 proposal,21
but one may presume, given the Agency’s intention to set the 2010 standard to
“reflect the level of emissions resulting from the co-benefits of controlling SO and
2
19 Ibid., Section V. F., p. 4710.
20 Ibid., pp. 4711, 4708.
21 Table 8, on p. 4712 of the proposal preamble, does provide a cost estimate of Section 111
plus the Interstate Air Quality Rule combined, but there is no separate estimate for §111.

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NOx”22 under its separate Interstate Air Quality Rule,23 that no controls would be
required to specifically address mercury emissions in 2010. In that case, the
incremental cost of controlling mercury would be zero under Section 111. No cost
estimates are provided for the 2018 standard under Section 111 either, but the
Agency states that “such controls should not have any significant impact on power
availability, reliability, or pricing. Nor should a 15-ton cap cause any significant shift
in the fuels currently utilized by power plants or in the source of these fuels.”24 (In
fact, the Agency projects that coal production for the electric power sector will
increase 147 million tons, or 16%, by 2010.25)
EPA’s analysis of the Interstate Air Quality Rule (IAQR), like its analysis of the
mercury MACT proposal, shows disproportionate costs and benefits. Annual
benefits of the rule are estimated at $58 billion in 2010, with annual social costs of
$3 billion; in 2015, when the IAQR is fully implemented, annual benefits are
estimated at $84 billion versus social costs of $4 billion.26
Should the Standards Be More Stringent? Given these analyses, some
question why the regulations should not be more stringent, or implemented more
quickly. EPA’s response appears to be that the technology required for mercury
control will not be adequately demonstrated until after 2010,27 and that the
technologies for SO and NOx, while available now, cannot be implemented at a
2
faster pace without causing “extremely high” costs and overwhelming the capacity
of equipment suppliers.28
These conclusions are among the issues likely to be questioned in the public
comment period, which has been extended through June. The Agency’s concerns
with regard to the availability and cost of technology appear to be at odds with the
views of a number of experts. For example, a recent paper co-authored by
representatives of two power companies, the Electric Power Research Institute, the
22 The quote is from Table 9, note 2, p. 4712. The rationale is also discussed in Section IV.
D.2 of the proposal at p. 4698. Another approach would be to assume that Section 111
requires a 34-ton emission limit (as Table 9 implies). In that case, the estimated compliance
cost might be as high as that of MACT, although it would depend on whether the same or
a different subset of facilities are assumed to install controls.
23 The proposed Interstate Air Quality Rule (IAQR) appeared in the Federal Register on the
same day as the Mercury Proposal (69 Federal Register 4565, January 30, 2004). The IAQR
proposes to reduce power plant emissions of SO and NOx in 29 Eastern states about 40%
2
by 2010 and 70% by 2015. These reductions mirror those that would be required by the
Administration’s Clear Skies bill, but only for Eastern states.
24 Mercury proposal, Section IV.D.2, p. 4699.
25 Ibid., Section VI.H., p. 4715.
26 U.S. EPA, Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone
(Interstate Air Quality Rule); Proposed Rule, Section I.A., 69 Federal Register 4571,
January 30, 2004.
27 Mercury Proposal, Section IV.D.2., p. 4698.
28 Ibid.

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CRS-10
U.S. Department of Energy, and ADA-ES, a leading consultant on advanced mercury
control technologies concludes:
Recent full-scale field tests have proven the effectiveness of activated
carbon injection for reducing mercury emissions. This technology is
ideally suited for use on existing coal-fired boilers as it provides the
following advantages:
! Minimal capital cost of equipment (<$3/kW);
! Can be retrofit with little or no downtime of the operating
unit;
! Effective for both bituminous and subbituminous coals;
! Can achieve 90% removal when used with a fabric filter that has
been designed properly for carbon injection; and
! It can be integrated to enhance mercury capture with
virtually every configuration of air pollution control
equipment including ESPs [electrostatic precipitators], fabric
filters, wet and dry scrubbers.29
The Agency also appears not to have incorporated the conclusions of its own
Office of Research and Development (ORD) in determining the level of emissions
control being achieved at the best controlled existing plants. In a white paper posted
on the EPA website March 2, 2004, ORD concluded that fabric filters, a relatively
simple technology that is currently installed on more than 12% of power plants,
achieve a 90% reduction in mercury emissions at bituminous coal plants and a 72%
reduction at subbituminous plants. The addition of a scrubber increased the emission
reduction to 98% at bituminous plants, according to ORD.30
The white paper further stated that, by 2010, activated carbon injection with a
fabric filter “has the potential to achieve 90% Hg reduction” on any rank of coal, and
could be installed within 1-2 years of signing a contract to do so.31 Since the white
paper was written, there have been reports that a European firm, Donau Carbon, has
begun offering commercial guarantees for mercury removal from coal-fired power
plants using ACI technology.32
29 Michael Durham, et al., “Full-Scale Results of Mercury Control by Injecting Activated
Carbon Upstream of ESPs and Fabric Filters,” paper presented at PowerGen 2003, Las
Vegas, NV, December 9-11, 2003, p. 19.
30 U.S. EPA, Office of Research and Development, “Control of Mercury Emissions from
Coal-Fired Electric Utility Boilers,” undated, posted March 2, 2004, available at
[http://www.epa.gov/ttn/atw/utility/hgwhitepaperfinal.pdf].
31 Ibid., pp. 13-15.
32 Personal communication, U.S. EPA, Office of Air and Radiation, May 21, 2004.

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CRS-11
Hot Spots. One of the main criticisms of the cap and trade proposal is that it
would not address “hot spots,” areas where mercury emissions and/or concentrations
in water bodies are greater than elsewhere. EPA has developed data on such hot
spots: Environmental Defense released a report on December 9 based on EPA’s data
that concluded: “At hot spots, local sources within a state commonly account for 50%
to 80% of the mercury deposition.”33
That the local contribution to hot spot concentrations is this high is disputed by
utility sources, particularly for mercury emitted by power plants. Utility
spokespersons argue that much of the mercury emitted by utilities is in the elemental
form, is non-water soluble, and is released from taller stacks. The result, they say,
is that it is less available to fish and disperses over a wider area – with much of it
entering a global mercury cycle.34
The concern over hot spots, and the impetus to address them, were recently
reinforced by a study of mercury contamination in the Everglades. The study found
that concentrations of mercury in fish and wading birds in the area dropped around
75% after Florida imposed stringent controls on incinerators and other local sources
of mercury emissions in the 1990s.35 Backers of strong controls on utility emissions
have cited these results in arguing against a cap and trade approach.
Unless a national cap is so stringent that it requires virtually all facilities to
impose some form of emission control, cap and trade programs do not appear well
designed to address hot spots. They allow facilities to purchase allowances and avoid
any emission controls, if that is the compliance approach that makes the most sense
to a plant’s owners and operators. If plants near hot spots purchase allowances rather
than install controls, the cap and trade system may not have an impact on mercury
concentrations at the most contaminated sites. By contrast, a MACT standard
requires reductions at all plants, and would therefore be expected to improve
conditions at hot spots.
EPA’s response to this is threefold.36 First, it notes that all states would remain
free to establish more stringent controls to address local health-based concerns
separate from the mercury cap-and-trade program requirements. But it goes on to
state that the Agency does not anticipate hot spots, for two reasons. First, the
Agency’s modeling suggests that larger coal-fired units, which have the highest
33 Environmental Defense, Out of Control and Close to Home, December 2003, p. 12.
34 See Electric Power Research Institute written statement, as quoted in “Backers of Utility
Rules Expect Florida Study of Effect of Mercury to Affect EPA Decisions,” Bureau of
National Affairs, Daily Environment Report, November 19, 2003, p. A-10. Also, see EPRI’s
p r e s s s t a t e m e n t , “ P o w e r P l a n t s a n d M e r c u r y , ” a v a i l a b l e a t
[http://www.epri.com/corporate/discover_epri/news/HotTopics/env_mercury.pdf].
35 Florida Department of Environmental Protection, Integrating Atmospheric Mercury
Deposition With Aquatic Cycling in South Florida, revised November 2003, available at
[ftp://ftp.dep.state.fl.us/pub/labs/assessment/mercury/tmdlreport03.pdf]. See especially, pp.
56-59.
36 Mercury proposal, 69 Federal Register 4702-4703.

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CRS-12
“local deposition footprints,” are likely to control emissions more than required and
sell excess allowances achieved through overcompliance to smaller units. Second,
mercury emissions come in several forms. The most difficult to control is elemental
mercury, according to the Agency, and it is the most likely to be transported long
distances from the generating units. Thus, if plants focus on the more easily
controlled forms of mercury, they will control mercury that would more likely be
deposited locally. The Agency requests further comments on its analysis, and raises
the possibility that it could adjust the trading program to favor controls at units in
sensitive areas.37
Effects on Eastern and Western Coal. Whether imposition of controls
on mercury will affect the total amount and/or the types of coal consumed at the
nation’s power plants is another issue raised by critics of EPA’s proposed
regulations. The United Mine Workers of America, for example, in comments to the
EPA Rulemaking Docket, concluded that:
EPA’s proposed mercury MACT standards could be met by a majority of
western subbituminous coals without the need for any emission control
technologies. Eastern bituminous coals, representing roughly one-half of
domestic coal production, would need to meet an average emission
removal rate of 75% .... The MACT proposal is a recipe for massive fuel-
switching from eastern to western coals that would disrupt coal-producing
regions throughout the East ....38
The MACT standard, as proposed, would set plant-specific emission limits for
five subcategories of utilities, based on coal rank (i.e., coal type) or technology. The
five subcategories are: bituminous, subbituminous, lignite, integrated coal
gasification combined cycle (IGCC), and coal refuse.39 The standards would apply
to each plant individually. There would be no averaging, banking, or trading of
emission allowances.40 The proposed standards and the number of existing units to
which each applies are summarized in Table 2.
As can be seen in the table, bituminous (largely eastern) coal would have a far
lower emission limit under the proposed MACT standard than would subbituminous
or lignite (largely western) coals. Why? The proposed limits reflect the statutory
minimum requirement for MACT standards, established in Section 112(d) of the
Clean Air Act. This subsection requires that MACT standards be at least as stringent
as the reductions achieved in practice by the best performing 12% of sources (for
37 Ibid., p. 4701.
38 Comments of Cecil E. Roberts on behalf of the United Mine Workers of America to EPA
Docket ID No. OAR-2002-0056, April 30, 2004, p. 1.
39 For a description of these subcategories, see the Mercury proposal at 69 FR 4665-7.
40 There are two forms of flexibility, however: 1) the standard is expressed as a rolling 12-
month average, rather than a limit that must be met at all times; and 2) a plant can average
all the units at its location in determining compliance. Both of these factors reduce the
stringency of the standard.

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CRS-13
existing sources) or the best single source (for new sources) within the subcategories
EPA chooses for an industry.
The best-performing power plants – whether bituminous, subbituminous or
lignite – are those with scrubbers and fabric filters. These controls were installed
primarily to capture sulfur dioxide, but they have the cobenefit of reducing emissions
Table 2. Mercury Emission Standards Under the
Proposed Utility MACT Rule
(in 10-6 lb/MWh)
Subcategory
Number of
Proposed
Proposed
Existing Units
Standard
Standard (New
(Existing Units)
Units)
Bituminous
701
21
6.0
Subbituminous
236
61
20
Lignite
24
98
62
IGCC
2
200
20
Coal refuse
17
4.1
1.1
Source: U.S. EPA, Mercury Proposal, pp. 4662-3 (standards). RTI International (number of
units). The standards for existing units are also expressed in the proposal on a heat input
basis (i.e., lbs. Hg per trillion Btu). Existing units may comply with either the input or
output-based limit.
of mercury. EPA notes that it is easier for this control equipment to capture mercury
from bituminous plants because of the speciation of the mercury emissions: more of
the mercury is particle-bound or oxidized in emissions from eastern bituminous
plants, and less is in elemental form, as compared to mercury emissions from western
subbituminous and lignite coal plants. Even bituminous plants without scrubbers can
capture high amounts of mercury if they have particulate controls such as fabric
filters (also known as baghouses).
For these reasons, EPA’s proposal sets more stringent limits on emissions from
bituminous plants: as shown in Table 3, the proposed MACT rule’s costs and
reductions in emissions come almost entirely from controls on bituminous units.
According to EPA, all of the net emission reductions occur in the bituminous sector,
and 97% of the rule’s cost is borne by bituminous units.
EPA’s analysis, while differing on the degree of impact, agrees with the United
Mine Workers that the proposed MACT rule would lead to less use of eastern coal
and would increase use of western coal. The Integrated Planning Model, which EPA
uses to assess the impact of proposed regulations on utilities and the coal industry,
divides the coal-producing states into several geographic regions: Appalachian
(including Pennsylvania, Ohio, West Virginia, Eastern Kentucky, Tennessee and

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CRS-14
Alabama); Interior (including Illinois, Indiana, and Western Kentucky); and Western
(principally the Rocky Mountain states and North Dakota, including the Powder
River basin). In EPA’s analysis, use of coal from Interior states would be unchanged
as a result of the MACT rule, but Appalachian coal use would decline, while western
coal use would increase. This analysis is summarized below in Table 4.
Table 3. Estimated Emission Reductions and Cost of Proposed
Utility MACT Rule, by Coal Type
Coal Rank*
Tons of Mercury
Annual Cost
Reduced
(in million 1999 $)
Bituminous
15.2
$1,551
Subbituminous
-0.4**
47**
Lignite
-0.1**
2**
Total
14.6
1,600
* Coal types (or ranks) differ in their age, carbon content, heating value, volatile content,
and amount of moisture. Lignite coals, the youngest or lowest rank, have relatively low
heating value and high moisture and volatile content. Bituminous coals have higher heating
value and lower moisture. Subbituminous fall in between.

** Total emissions increase for these subcategories because of an approximately 20%
increase in use of these types of coal. On a per unit basis, however, emissions are subject
to a modest level of control; hence some cost.
Source: U.S. EPA, Clean Air Markets Division, “Economic and Energy Impact Analysis for
the Proposed Utility MACT Rulemaking, January 28, 2004.
Table 4. Estimated Changes in Coal Use from Imposition of the
Proposed Utility MACT Rule, 2000-2010, by Region
(in million tons)
Coal Supply
Year 2000
2010 Base Case
2010 with MACT
Region
(no MACT Rule)
Appalachia
299
315
303
Interior
131
177
177
Western
475
536
554
National Total
905
1,028
1,034
Source: U.S. EPA Clean Air Markets Division, previously cited.
Surprisingly, EPA did not estimate the effects on coal choice of its cap and trade
proposals. Despite the fact that cap and trade is described by EPA as its preferred
approach to mercury control, there is no economic analysis of that proposal in the

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CRS-15
docket. Likewise, EPA did not analyze the impacts of the MACT rule combined
with the Interstate Air Quality Rule, which would control SO and NOx emissions
2
from many of the same utility sources – even though the connections between the
controls for mercury and the other two pollutants stimulated the Agency to
simultaneously propose the MACT and IAQR rules.
Finally, it is important to note that negative impacts on eastern coal are not
inherent in the imposition of mercury controls. Rather, they result from EPA’s
decisions regarding subcategorization of the utility industry and its decision not to
go beyond what it viewed as the statutory minimum requirement for MACT
standards.41
Legislation in the 108th Congress42
Although EPA is proceeding to develop standards for electric utility mercury
emissions under both Sections 111 and 112 of the Clean Air Act, the Administration
has also proposed that Congress amend the act by passing multi-pollutant legislation
for utilities, which it refers to as the “Clear Skies” bill. Clear Skies (H.R. 999 / S.
485) would replace more than half a dozen specific regulatory programs for electric
power plants with a “cap and trade” program for three pollutants: sulfur dioxide
(SO ), nitrogen oxides (NOx), and mercury. Several other mercury bills also have
2
been introduced. For a comparison of Clear Skies and these bills, see Table 2.43
[On November 10, 2003, Senator Inhofe introduced a variant of the Clear Skies
bill (S. 1844). This bill is also entitled the Clear Skies Act. The Administration
appears to support this revised bill, which contains less stringent mercury
requirements than the original Clear Skies or any of the other bills. The following
discussion uses the term “Clear Skies” for the original bill, but notes key differences
in S. 1844.]
41 For example, see United Mine Workers of America (UMWA) comments, previously
cited, p. 4. UMWA notes that within the Mercury MACT Working Group, a varied group
of stakeholders that advised the Agency from 2001 to 2003, an industry group that included
all major coal producers and virtually the entire electric utility industry proposed tighter
standards than EPA ultimately chose for the subbituminous and lignite subcategories. Had
the Agency adopted such tighter standards, a major incentive to switch to western coal could
have been eliminated. Similarly, if the standard for the industry as a whole were more
stringent (under either a cap and trade or MACT rule), the incentive to switch to eastern coal
would likely be lessened or eliminated, since users of western coal could not escape the need
to install controls.
42 This report focuses on mercury emissions to the air and on legislation to address such
emissions. Congress is also considering legislation to reduce the amount of mercury in
products and waste streams. For information on mercury in products and wastes, including
congressional and state actions on the subject, see CRS Report RL31908, Mercury in
Products and Waste: Legislative and Regulatory Activities to Control Mercury.
43 There were also bills introduced in the 107th Congress. One of these, Sen. Jeffords’ S.
556, which is similar to this Congress’s S. 366, was reported by the Environment and Public
Works Committee (S.Rept. 107-347), but no further action was taken.

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CRS-16
Under the Clear Skies bill, the programs that would be replaced include New
Source Review, Prevention of Significant Deterioration, New Source Performance
Standards, the NOx SIP call,44 nonattainment area requirements, Best Available
Retrofit Technology, and the mercury MACT. (For a discussion of these programs’
requirements, see CRS Report RL30878, Electricity Generation and Air Quality:
Multi-Pollutant Strategies, pp. 5-11, 29-35.)
In replacing the mercury MACT requirement, Clear Skies would also eliminate
the current law’s “residual risk” provisions (Section 112(f)), under which EPA is
required to address remaining risks posed to human health and the environment eight
years after the imposition of MACT standards. Residual risk standards are required
to provide “an ample margin of safety to protect public health.” As noted previously,
this program has not yet been implemented for any source of hazardous air pollutants,
but it could lead to more stringent requirements if and when implemented.
Under Clear Skies’ cap and trade program, national or regional limits would be
established for total utility emissions of each of the three pollutants. For mercury,
the bill proposes a national limit of 26 tons of emissions in 2010 (a 50% reduction
from 1994-1995 levels), and 15 tons in 2018 (a 70% reduction).45 The revised bill
introduced by Senator Inhofe, S. 1844, sets the 2010 cap at 34 tons. These amounts
are expected to be attainable for the most part as co-benefits of installing emission
controls for sulfur dioxide and nitrogen oxides: EPA’s analysis concludes that only
about 2% of coal-fired capacity would install mercury-specific controls by 2010, even
with a 26-ton cap.46
Each existing utility would receive “allowances” to emit specific amounts of
mercury, based on their current emission levels. As the national cap becomes more
stringent, the allowances given to each source would be reduced, and increasingly
over time, allowances would be auctioned to the highest bidders. Individual utilities
could comply with the standards either by reducing emissions, by purchasing excess
allowances from other utilities that have reduced emissions more than required, or
by using allowances from previous years that they have “banked” (i.e., not used).
The proposal would allow companies to generate allowances through early
reductions, and bank them for future use. It also assumes that mercury emissions are
a national problem, and that it makes little difference where reductions in emissions
occur, a point that opponents of allowances disagree with, based on concerns over the
44 The NOx SIP call refers to regulations under which State Implementation Plans in 22
eastern states and the District of Columbia must be revised to control NOx emissions in
order to improve ozone air quality in downwind states.
45 Some of this reduction has already been achieved. EPA estimates 1999 emissions of
mercury from power plants at 48 tons, a reduction of 7.7% compared to the 1994-995 base.
Since 1999, additional pollution controls have been installed to reduce SO2 and NOx
emissions in response to Phase 2 of the acid rain program and the NOx SIP call, further
reducing mercury emissions as a co-benefit.
46 U.S. EPA, The Clear Skies Act, Technical Support Package, July 11, 2003, Section G.,
p. 3, available at [http://www.epa.gov/air/clearskies/econ.html]. The analysis states that only
2-6 gigawatts (GW) of generation would install activated carbon injection in 2010 under
Clear Skies. Total coal-fired electric generating capacity is approximately 300 GW.

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CRS-17
regional variation in mercury deposition described earlier. The Clear Skies
allowance program is based on the Clean Air Act’s current program for acid
precipitation, which is credited with achieving reductions faster and greater than
required at a small fraction of the projected cost.
Most other legislation would reduce mercury emissions more and faster than
Clear Skies. Under Senator Jeffords’ S. 366, for example, utility mercury emissions
would be reduced to a total of 5 tons (i.e., greater than 90%) by 2008. Senator
Leahy’s S. 484 and Representative Waxman’s H.R. 2042 would set comparable
requirements, a reduction of at least 90% from 1999 levels within three-and-a-half
years of the bill’s enactment (Leahy) or January 1, 2009 (Waxman). Under the
Jeffords, Leahy, and Waxman bills, there would be no allowance trading and banking
programs for mercury. Senator Leahy’s bill also would set stringent standards for
commercial and industrial boilers, chlor-alkali plants and Portland cement plants, and
would require the separation of mercury-containing items from solid waste. The
Leahy, Jeffords, and Waxman bills would also require EPA to ensure that mercury
captured by emission controls is not re-released into the environment.
Senator Carper’s S. 843 and its House counterpart, Representative Bass’s H.R.
3093, present a middle ground between Clear Skies and the Jeffords, Leahy, and
Waxman bills. Like Clear Skies, the Carper/Bass bill focuses only on coal-fired
electric generating units, and it would establish a tradeable allowance program to
ease compliance. But it would mandate sharper reductions sooner than the
Administration bill – an 80% reduction in mercury emissions by 2013.
Under Representative Sweeney’s H.R. 203, the Clean Air Act’s existing
provisions for mercury are essentially restated, with EPA to promulgate regulations
for utility mercury emissions by December 15, 2004.
Conclusion
High concentrations of mercury in aquatic environments, and the resulting
advisories to limit consumption of fish in order to protect human health, have
focused attention on the role of mercury emissions from a variety of sources. Among
the principal sources of mercury emissions, coal-fired power plants are the largest
source and are the last category for which regulations have been proposed. Under a
consent agreement, however, EPA agreed to propose regulations controlling mercury
emissions from this category by December 15, 2003 (a deadline it met), with
promulgation one year later. The Agency is considering several options regarding
the form of these regulations.
While moving forward with the development of these regulations, EPA is, at the
same time, asking Congress to eliminate the regulatory requirement in favor of a
statutory cap and trade program for mercury and two other pollutants, through its
Clear Skies bill. EPA has maintained that enacting Clear Skies will reduce mercury
emissions with greater certainty and sooner than would the existing regulatory
authority. The statement assumes that litigation will delay the implementation of
MACT standards by three or more years, and that legislation will be enacted sooner,
not later. It also assumes that we would start to see the benefits “immediately upon

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CRS-18
passage of the legislation,” presumably because companies would have an interest
in banking credits for use or sale at a later date.47
Others in Congress have proposed legislation that would reduce mercury
emissions from power plants to a greater degree and faster than Clear Skies. If
swiftness and certainty are the main selling points of a legislative approach, Clear
Skies is not the only available solution.
On the other hand, if the goal is to minimize cost by relying on co-benefits from
the control of other pollutants, Clear Skies (or its regulatory cousins, the Interstate
Air Quality Rule and the Section 111 mercury proposal) may be the preferred
alternative. Emission controls designed to capture other pollutants have the effect
of reducing mercury emissions. EPA notes, for example, that existing controls for
sulfur dioxide and nitrogen oxides had already reduced mercury emissions from
power plants by about one-third as of 1999.48 The Administration’s Clear Skies bill
and its Section 111 proposal rely almost entirely on such co-benefits to achieve their
mercury reductions: 2% or less of coal-fired electric capacity would need to install
equipment specifically designed to reduce mercury by 2010 to achieve the reductions
in mercury emissions required by the Clear Skies bill in its first phase. The 2018
(Phase 2) requirements also rely almost entirely on co-benefits to achieve the
required 70% reduction in emissions, according to EPA’s analysis.49
This situation raises equity concerns: other combustion sources (municipal
waste combustors and medical waste incinerators) have been required to reduce
emissions more than 90% under existing Clean Air Act authority, with considerably
shorter deadlines than those in Clear Skies or the Section 111 proposal. Since similar
technologies could be applied to coal-fired power plants, the absence of a
requirement to do so is a notable feature of the Administration’s legislative and
regulatory approaches. Also notable is the elimination of any future residual risk
regulations, which remain a possibility for other sources of mercury.
With the 1990 Clean Air Act amendments, however, Congress determined that
electric utilities would be treated differently from other sources of hazardous air
pollutants. The amendments required that EPA report to Congress before
determining whether regulating utility emissions of these pollutants was appropriate
and necessary. The special treatment for electric power producers was motivated by
a number of factors, including a desire to preserve the use of coal as an energy
47 Statement of EPA Administrator Christine Todd Whitman, Fiscal Year 2004 Budget of
the Environmental Protection Agency, Hearing, Senate Environment and Public Works
Committee, February 26, 2003.
48 Ellen S. Brown, Office of Air and Radiation, U.S. EPA, “Overview of the Utility MACT
Development and Issues,” presentation to the Environmental and Energy Study Institute,
March 7, 2003, p. 3.
49 See ICF Consulting, “Updated Financial Impact Analysis of a Multi-Pollutant Emissions
Policy,” 2003 Update, November 20, 2003, p. 7, available at
[http://www.epa.gov/air/clearskies/pdfs/yag1975-20031120.pdf]. The analysis concludes
that only 1% of utility coal-fired capacity would install mercury-specific controls under a
three-pollutant program such as Clear Skies.

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CRS-19
option, for both economic and energy security reasons. Whether these concerns
continue to justify more lenient treatment of the utility sector, or whether
environmental and equity concerns outweigh them, will be at the core of
congressional debate over mercury issues.

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CRS-20
Table 5. Comparison of Mercury Emission Legislation
Provisions
H.R. 203
H.R. 999/S. 485
H.R. 2042
S. 366
S. 484
S. 843/
S. 1844
(Sweeney)
(Barton/Inhofe, by
(Waxman)
(Jeffords)
(Leahy)
H.R. 3093
(Inhofe)
request)
(Carper/
(Administration’s
Bass)
Clear Skies bill)
Pollutants
mercury, SO ,
mercury, SO , NOx
mercury,
mercury,
mercury
mercury,
mercury,
2
2
covered
NOx
SO , NOx,
SO , NOx,
SO , NOx,
SO , NOx
2
2
2
2
and CO
and CO
and CO
2
2
2
Affected
electric utility
existing coal-fired
electric
coal-fired
fossil fueled utility
coal-fired
same as
electric
sources (not
electric generating
generating
electric
steam generating
electric
Clear
generating
further defined)
facilities 25 MW or
facilities 15
generating
units
generating
Skies
units
greater and new
MW or
facilities 15
facilities 25
coal-fired units of
greater
MW or
MW or
all sizes
greater
greater
Mercury
EPA to
26 tons in 2010; 15
4.8 tons by
5 tons by
about 5 tons (at
24 tons by
34 tons in
emissions
promulgate
tons in 2018
2009 (90%
2008
least 90%
2009; 10
2010; 15
cap
regulations by
reduction
reduction from
tons by
tons in
December 15,
from 1999
1999 levels ) three
2013
2018
2004
levels)
and a half years
after enactment
Trading
no trading for
tradeable allowance
no trading
no trading
no trading for
tradeable
tradeable
provisions
mercury
system
for mercury
for mercury,
mercury, but
allowance
allowance
but allows
allows plantwide
system
system
plantwide
averaging
averaging

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CRS-21
Provisions
H.R. 203
H.R. 999/S. 485
H.R. 2042
S. 366
S. 484
S. 843/
S. 1844
(Sweeney)
(Barton/Inhofe, by
(Waxman)
(Jeffords)
(Leahy)
H.R. 3093
(Inhofe)
request)
(Carper/
(Administration’s
Bass)
Clear Skies bill)
Residual
not addressed;
coal-fired electric
current
not
not addressed;
EPA would
same as
risk
thus, current
generating facilities
Section 112
addressed;
thus, current
be required
Clear
Section 112
would be exempt
authority is
thus, current
Section 112
to address
Skies
authority is
from MACT and
retained
Section 112
authority is
residual
retained, allowing
residual risk
authority is
retained
risk and if
EPA to set more
requirements for
retained
necessary
stringent
mercury emissions
promul-
standards to
gate
address any
standards
residual risk in
eight years
December 2012
after
enactment
Penalties for
not specified;
penalty equals the
not
three times
not specified;
$10,000 per
same as
non-
Clean Air Act
clearing price for
specified;
the average
Clean Air Act
pound
Clear
compliance
enforcement
emission allowances
Clean Air
mercury
enforcement
(adjusted
Skies
provisions would
plus a one-to-one
Act
control cost
provisions would
for
apply
offset from future
enforce-
per gram of
apply
inflation)
emission
ment
excess
plus one-
allocations, if paid
provisions
emissions
for-one
within 30 days;
would apply
offset from
otherwise the
future
penalty is 3 times
emission
the clearing price
allocations
plus offsets

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CRS-22
Provisions
H.R. 203
H.R. 999/S. 485
H.R. 2042
S. 366
S. 484
S. 843/
S. 1844
(Sweeney)
(Barton/Inhofe, by
(Waxman)
(Jeffords)
(Leahy)
H.R. 3093
(Inhofe)
request)
(Carper/
(Administration’s
Bass)
Clear Skies bill)
Non-electric
yes – requires
no
not later
yes – not
yes – requires at
no; requires
no
generating
EPA to
than two
later than
least 90% emis-
a report to
sources
promulgate
years after
January 1,
sion reduction for
Congress
affected?
regulations
enactment,
2005, the
coal- and oil-fired
on the use
controlling
EPA shall
EPA Admi-
commercial and
of captured
industrial source
promulgate
nistrator
industrial boilers
or
mercury
regulations
shall pro-
and at least 95%
recovered
emissions by
to ensure
mulgate
reduction for chlor-
mercury 18
December 15,
that any
regulations
alkali and Portland
months
2004
captured or
to ensure that
cement plants;
after
recovered
any mercury
EPA to promulgate
enactment
mercury is
captured by
rules requiring
not re-
emission
separa-tion of
released
controls at an
mercury-
into the
electric
containing items
environ-
generating
from solid waste
ment
facility is not
streams; also
re-released
requires EPA to
into the
promulgate
environ-
regulations to
ment; this
ensure that any
requires
mercury captured
regulations
by emission
on disposal
controls at an
and reuse of
electric generating
coal
facility is not
combustion
re-released into the
waste
environment

---

CRS-23
Provisions
H.R. 203
H.R. 999/S. 485
H.R. 2042
S. 366
S. 484
S. 843/
S. 1844
(Sweeney)
(Barton/Inhofe, by
(Waxman)
(Jeffords)
(Leahy)
H.R. 3093
(Inhofe)
request)
(Carper/
(Administration’s
Bass)
Clear Skies bill)
Other
requires EPA to
allows more
allows
allows more
allows more
allows
provides
determine by
stringent state
additional
stringent
stringent state
more
for
12/31/11 whether
standards; also,
reductions
state
standards
stringent
research
additional
EPA, in
if EPA
standards;
state
and
standards are
consultation with
determines
ecosystem
standards;
reports to
necessary to
DOE, is to study
the
protection
also, not
Congress
protect sensitive
and report to
specified
provisions
later than
on
ecosystems and, if
Congress by July 1,
reductions
identical to
15 years
mercury,
so, to promulgate
2009 whether
are not
H.R. 203
after
but does
them by 12/31/13;
mercury limits
reasonably
enactment,
not
does not address
should be adjusted
anticipated
EPA may
authorize
state standards
based on cost-
to protect
revise the
more
(under current
benefit analysis and
public
annual
stringent
law, they may be
the cost-
health or
tonnage
standards
more stringent)
effectiveness of
welfare;
limit, after
controlling various
does not
consider-
sources of mercury
address
ing impact
emissions
state
on health,
standards
environ-
(under
ment,
current law,
economy,
they may be
and costs,
more
with
stringent)
revised
standards
to take
effect 20
years after
enactment

---