Regulatory Finding on the Emissions of Hazardous Air Pollutants From Electric Utility Steam Generating Units

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[Federal Register: December 20, 2000 (Volume 65, Number 245)]
[Notices]
[Page 79825-79831]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20de00-66]

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ENVIRONMENTAL PROTECTION AGENCY

[AD-FRL-6919-6]
2060-ZA10

Regulatory Finding on the Emissions of Hazardous Air Pollutants
From Electric Utility Steam Generating Units

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of regulatory finding.

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SUMMARY: This notice presents EPA's finding required by section
112(n)(1)(A) of the Clean Air Act (CAA) as to whether regulation of
emissions of hazardous air pollutants (HAP) from fossil fuel-fired
electric utility steam generating units (as defined in section
112(a)(8) of the CAA) is appropriate and necessary. This finding is
based on the results of EPA's February 1998 ``Study

[[Page 79826]]

of Hazardous Air Pollutant Emissions from Electric Utility Steam
Generating Units--Final Report to Congress' (utility RTC), and on
information obtained subsequent to the utility RTC concerning HAP
emissions to the atmosphere from electric utility steam generating
units. In the utility RTC, the EPA indicated that coal- and oil-fired
electric utility steam generating units are significant emitters of
HAP, including mercury which is emitted from coal-fired units, and
which EPA identified as the HAP of greatest concern to public health
from the industry. Based on the available information, the
Administrator finds that regulation of HAP emissions from coal- and
oil-fired electric utility steam generating units under section 112 of
the CAA is appropriate and necessary. As a result, this notice adds
coal-and oil-fired electric utility steam generating units to the list
of source categories under section 112(c) of the CAA. Also in the
utility RTC, the EPA indicated that the impacts due to HAP emissions
from natural gas-fired electric utility steam generating units were
negligible based on the results of the study. The Administrator finds
that regulation of HAP emissions from natural gas-fired electric
utility steam generating units is not appropriate or necessary. The EPA
does not believe that the definition of electric utility steam
generating unit found in section 112(a)(8) of the CAA encompasses
stationary combustion turbines. Therefore, the finding concerning
natural-gas fired electric utility steam generating units does not
apply to stationary combustion turbines.

ADDRESSES: Docket No. A-92-55, containing information used in
development of this notice, is available for public inspection and
copying between 8:00 a.m. and 5:30 p.m., Monday through Friday,
excluding legal holidays. The docket is located in EPA's Air and
Radiation Docket and Information Center, Waterside Mall, Room M-1500,
401 M Street, SW, Washington, DC 20460, or by calling (202) 260-7548. A
reasonable fee may be charged for copying docket materials.

FOR FURTHER INFORMATION CONTACT: Mr. William Maxwell, Emission
Standards Division (MD-13), U.S. EPA, Research Triangle Park, North
Carolina 27711, telephone number (919) 541-5430, facsimile number (919)
541-5450, electronic mail address maxwell.bill@epa.gov>.

SUPPLEMENTARY INFORMATION: Docket. The docket is an organized file of
all the information submitted to or otherwise relied upon by EPA in the
development of this regulatory finding. The principal purpose of the
docket is to allow interested parties to identify and locate documents
that serve as a record of the process engaged in by EPA which resulted
in the publication of today's finding.
World Wide Web. In addition to being available in the docket, an
electronic copy of today's notice will be posted on the Technology
Transfer Network's (TTN) policy and guidance information page http://
www.epa.gov/ttn/oarpg> under ``Recent Actions.'' The TTN provides
information and technology exchange in various areas of air pollution
control. If more information regarding the TTN is needed, call the TTN
HELP line at (919) 541-5384.

I. What Is the Statutory Authority and Background of This Finding?

Today's finding is issued under the authority of section
112(n)(1)(A) and 112(c) of the CAA. Section 112(n)(1)(A) requires that,
after considering the results of the study mandated by the same section
and reported in the utility RTC, the Administrator determine whether
regulation of HAP emissions from electric utility steam generating
units is appropriate and necessary. The study was initiated following
enactment of the 1990 Amendments to the CAA, which included section
112(n)(1)(A). Data were gathered, and the utility RTC was prepared.
Section 112(c) provides that the Administrator shall list categories of
sources of the air pollutants contained in the section 112(b) list. The
listing of source categories under section 112(c) is a dynamic process.
(See ``Initial List of Categories of sources under Section 112(c)(1) of
the Clean Air Act Amendments of 1990,'' 57 FR 31576.) Decisions as to
the description and scope of source categories listed will be perfected
during the course of the rulemaking process for each listed category
and will take account of improvements in available information and
analysis during the rulemaking. A draft utility RTC was submitted for
scientific peer review in July 1995, and, concurrently, was made
available for public review (60 FR 35393). A public meeting to obtain
comments from the scientific peer review panel was held on July 11-12,
1995 in Research Triangle Park, North Carolina. In addition, a public
outreach meeting was held on July 13, 1995 in Durham, North Carolina,
at which time the public was invited to present oral comments on its
interpretation of the ``results of the study.'' The utility RTC was
finalized in February 1998 and released to Congress and the public. In
the final utility RTC, the EPA stated that, for the utility industry,
mercury from coal-fired electric utility steam generating units was the
HAP of greatest concern for public health.
To further inform the regulatory finding, the EPA issued an
information collection request under the authority of section 114 of
the CAA to all coal-fired electric utility steam generating units
requesting coal data from such units for calendar year 1999. Certain
units were also required to conduct stack tests to evaluate their HAP
emissions. In addition, the EPA solicited data from the public through
a February 29, 2000 notice (65 FR 10783). Another public meeting was
held on June 13, 2000 in Chicago, Illinois, where the public was
invited to provide EPA with their views on what the regulatory finding
should be (65 FR 18992).
Further, the EPA undertook an evaluation of the mercury control
performance of various emission control technologies that are either
currently in use on electric utility steam generating units for
pollutants other than mercury or that could be applied to such units
for mercury control. The evaluation was conducted along with other
parties, including the Department of Energy (DOE).
In addition, at the direction of Congress, the EPA funded the
National Academy of Sciences (NAS) to perform an independent evaluation
of the available data related to the health impacts of methylmercury
and provide recommendations for EPA's reference dose (RfD--the amount
of a chemical which, when ingested daily over a lifetime, is
anticipated to be without adverse health effects to humans, including
sensitive subpopulations). The NAS conducted an 18-month study of the
available data on the health effects of methylmercury and provided EPA
a report of its findings in July 2000.

II. What Has EPA Learned From the Utility RTC and the Subsequent
Data-Gathering Activities?

The following four sections present a summary of the information
and conclusions presented in the utility RTC along with the information
obtained subsequent to publishing the utility RTC.

A. Health Hazard Assessment

The EPA evaluated exposures, hazards, and risks due to HAP
emissions from coal-, oil-, and natural gas-fired electric utility
steam generating units. Much of the assessment focused on inhalation
exposure. However, multipathway exposures (e.g., inhalation plus
ingestion) were considered for six HAP

[[Page 79827]]

(mercury, radionuclides, arsenic, cadmium, lead, and dioxins). The
assessment for radionuclides was relatively extensive and included
multipathway modeling for all facilities identified in the utility RTC.
The analysis for mercury was primarily based on information obtained
from EPA's December 1997 ``Mercury Study Report to Congress'' (mercury
RTC) and included a multipathway modeling assessment of mercury from
four model electric utility plants. Screening level multipathway
exposure modeling analyses were also conducted for arsenic and dioxins.
For the other two HAP (cadmium and lead), a qualitative assessment of
potential concerns for multipathway exposure was presented;
multipathway modeling was not conducted for those two HAP. The methods
and results of the analyses are presented in the utility RTC.
Based on the assessment of hazards and risks due to emissions of
HAP from electric utility steam generating units, mercury is the HAP of
greatest concern. Mercury is highly toxic, persistent, and
bioaccumulates in food chains. Mercury emitted from electric utility
steam generating units (and other sources), primarily in the elemental
or divalent forms, is transported through the atmosphere and eventually
deposits onto land or water bodies (with the divalent form depositing
nearer the source than the elemental form). Once deposited, the
chemical form of mercury can change (through a methylation process)
into methylmercury which is a highly toxic, more bioavailable, form
that biomagnifies in the aquatic food chain (e.g., fish). Nearly all
the mercury that accumulates in fish is methylmercury. Fish consumption
dominates the pathway for human and wildlife exposure to mercury. As of
July 2000, 40 States and American Samoa have issued fish advisories for
mercury. Thirteen of those States have issued advisories for all water
bodies in their State, and the other 27 States have issued advisories
for over 1,900 specific water bodies.
Because the developing fetus is the most sensitive to the effects
of methylmercury, the greatest concern is the consumption of mercury
contaminated fish by women of childbearing age. Also of particular
concern are subsistence fish-eating populations that may be consuming
fish from contaminated waterbodies. The EPA estimates that about 7
percent of women of childbearing age (i.e., between the ages of 15 and
44 years) are exposed to methylmercury at levels exceeding its RfD of
0.1 microgram per kilogram body weight per day (0.1 ug/kg/day). The
risk following exposures above the RfD is uncertain, but risk increases
with increasing exposure. About 1 percent of women have methylmercury
exposures 3 to 4 times the methylmercury RfD. The NAS, in its July 2000
report ``Toxicological Effects of Methylmercury,'' affirmed EPA's
assessment of methylmercury toxicity and the level of its RfD.
Most of the mercury currently entering U.S. water bodies and
contaminating fish is the result of air emissions which, following
atmospheric transport, deposit onto watersheds or directly to water
bodies. Wastewater discharges also contribute to environmental
loadings, but to a much lesser degree than air emissions. Based on
modeling conducted for the mercury RTC, the EPA estimates that roughly
60 percent of the total mercury deposited in the U.S. comes from U.S.
anthropogenic air emission sources; the percentage is estimated to be
even higher in certain regions (e.g., northeast U.S.). The remainder of
the mercury deposited from the air comes from natural emission sources,
reemissions of historic global anthropogenic mercury releases, and from
anthropogenic sources outside the U.S. In the mercury RTC, the EPA
concluded that, given the total mass of mercury estimated to be emitted
from all anthropogenic sources and EPA's modeling of the atmospheric
transport of emitted mercury, coal combustion and waste incineration
most likely bear the greatest responsibility for direct anthropogenic
mercury deposition to the continental U.S. Mercury emissions from waste
incineration (including municipal waste combustors and hospital/
medical/infectious waste incinerators) have been declining
substantially over the last decade largely due to regulations issued by
EPA. Electric utility steam generating units (which are not currently
regulated for mercury emissions) are the largest source of mercury
emissions in the U.S., estimated to emit about 30 percent of current
U.S. anthropogenic emissions. There is a plausible link between
emissions of mercury from anthropogenic sources (including coal-fired
electric utility steam generating units) and methylmercury in fish.
Therefore, mercury emissions from electric utility steam generating
units are considered a threat to public health and the environment. It
is acknowledged that there are uncertainties regarding the extent of
the risks due to electric utility mercury emissions. For example, there
is no quantification of how much of the methylmercury in fish consumed
by the U.S. population is due to electric utility emissions relative to
other mercury sources (e.g., natural and other anthropogenic sources).
Nonetheless, the available information indicates that mercury emissions
from electric utility steam generating units comprise a substantial
portion of the environmental loadings and are a threat to public health
and the environment. The EPA believes that it is not necessary to
quantify the amount of mercury in fish due to electric utility steam
generating unit emissions relative to other sources for the purposes of
this finding.
With regard to the other HAP, arsenic and a few other metals (e.g.,
chromium, nickel, cadmium) are of potential concern for carcinogenic
effects. Although the results of the risk assessment indicate that
cancer risks are not high, they are not low enough to eliminate those
metals as a potential concern for public health. Dioxins, hydrogen
chloride, and hydrogen fluoride are three additional HAP that are of
potential concern and may be evaluated further during the regulatory
development process.
The other HAP studied in the risk assessment do not appear to be a
concern for public health based on the available information. However,
because of data gaps and uncertainties, it is possible that future data
collection efforts or analyses may identify other HAP of potential
concern.

B. Emissions

In developing the utility RTC, the EPA examined HAP emissions test
data acquired by the DOE, electric utility companies and organizations,
and EPA itself. Further, using section 114 authority, the EPA obtained
data from each coal-fired electric utility unit to update and refine
the information on mercury emissions from such units. After evaluating
various methods to estimate the emissions, the EPA estimates that the
industry emitted 43 tons of mercury in 1999 from 1,149 units at 464
coal-fired plants.
The analyses of the data obtained are explained in the utility RTC
and in subsequent documentation. Table 1 of this notice presents
estimated 1990 and 2010 nationwide HAP emissions from electric utility
steam generating units as presented in the utility RTC. The estimates
account for projected changes in the population of units, fuel
consumption, and control device configurations. Coal- and oil-fired
electric utility steam generating units are major sources (as defined
in section 112(a)(1) of the CAA) of hydrogen chloride and hydrogen
fluoride emissions, emit a significant number of

[[Page 79828]]

the 188 HAP on the section 112(b) list, and are the leading
anthropogenic sources of mercury emissions in the U.S.

Table 1.--Selected Nationwide Estimated HAP Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Selected nationwide HAP
emissions estimates (tons/ ---------------------------------------------------------------
year) Oil Natural gas
HAP -----------------------------------------------------------------------------------------------
Coal
-------------------------------- 1990 2010 1990 2010
1990 2010
--------------------------------------------------------------------------------------------------------------------------------------------------------
Arsenic................................................. 61 71 5 3 0.15 0.25
Beryllium............................................... 7.1 8.2 0.5 0.4
Cadmium................................................. 3.3 3.8 1.7 0.9
Chromium................................................ 73 87 4.7 2.4
Dioxins................................................. 0.000097 0.000108 2 x 10-5 3 x 10-6
Formaldehyde............................................ .............. .............. .............. .............. 36 57
Hydrogen chloride....................................... 143,000 155,000 2,860 1,450
Hydrogen fluoride....................................... 19,500 27,500
Lead.................................................... 75 87 10.6 5.4
Manganese............................................... 164 219 9.3 4.7
Mercury................................................. 46 60 0.25 0.13
Nickel.................................................. .............. .............. 393 198 2.2 3.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

For mercury, it was estimated in the utility RTC that the industry
emitted approximately 46 tons in 1990 (51 tons in 1994) and was
projected to emit approximately 60 tons in 2010 from 1,026 units at 426
coal-fired plants. The new information obtained under section 114
authority corroborates the emissions estimates. The increase in the
number of units over that of the utility RTC results primarily from the
identification of additional co-generation facilities meeting the
section 112(a)(8) definition. The quality of the 1999 data is
considered to be significantly better than that of the data reported in
the utility RTC. Specific coal data, including the mercury content,
were obtained for each coal-fired unit in the U.S. over the entire
year; previously, State-average data were used. In addition, the
control performance of existing control devices for each of the three
major species of mercury (divalent, elemental, and particulate) were
available; for the utility RTC, only total mercury values were
available. The new data allowed EPA to significantly refine and improve
its analyses and evaluate various methodologies in estimating
nationwide mercury emissions from coal-fired electric utility steam
generating units.

C. Alternative Control Strategies

Recent data show the technologies used to control criteria
pollutants (particulate matter (PM), nitrogen oxides ( NOX)
and sulfur dioxide (SO2)) are effective in controlling
emissions of nearly all HAP except mercury. In addition, combinations
of controls for criteria pollutants can lead to varying levels of
control, and in some cases full control, of mercury emissions. The
application of technologies used to control mercury emissions in
conjunction with technologies used to control other pollutants, an
approach called multipollutant control, can substantially reduce or
offset the costs of HAP control.
Potential strategies for controlling mercury and other HAP
emissions include the use of: precombustion controls (e.g., fuel
switching, coal switching, coal cleaning); combustion modification
methods used to control NOX emissions; flue gas cleaning
technologies that can be used to control emissions of criteria
pollutants and HAP; and nontraditional controls such as demand side
management and energy conservation.
Conversion of coal- and oil-fired units to natural gas firing
effectively eliminates HAP emissions. Although conversion of coal-fired
units to oil combustion will decrease emissions of some HAP, including
mercury, it could increase emissions of others (especially nickel).
Because of the wide variability in the trace metal contents of coals,
switching coals generally may not result in consistently reduced HAP
emissions. Current methods of coal cleaning remove portions of the
trace metals contained within the coal; the average emissions
reductions range from approximately 30 percent for mercury to
approximately 50 percent for lead.
Nontraditional control methods (e.g., demand side management,
energy conservation, pollution prevention) have the potential to result
in reduced HAP emissions, but the extent to which that is possible is
currently uncertain. The nontraditional controls reduce HAP emissions
through the avoided generation of HAP rather than by their removal from
the exhaust gas stream.
Mercury in the flue gas from coal combustion may be present in
three different forms. The forms, called species, include elemental
mercury, divalent oxidized forms, and mercury adsorbed onto the surface
of fly ash or other particles. The capture of mercury is highly
dependent on the relative amount of mercury species that are present in
the flue gas. Particulate bound mercury can easily be removed in
conventional PM emission control devices such as electrostatic
precipitators (ESP) and fabric filters (FF). Divalent forms of mercury
are generally soluble in water and can be captured in wet scrubbers.
Wet flue gas desulfurization (FGD) systems generally capture more than
90 percent of the divalent mercury, which may represent a 20 to 80
percent removal of the total mercury. Elemental mercury is insoluble in
water, does not react with alkaline reagents used in FGD systems, and
cannot be captured in wet scrubbers. Both the elemental and divalent
forms of mercury can be adsorbed onto porous solids (e.g., fly ash,
powdered activated carbon, calcium-based acid gas sorbents) for
subsequent removal in a PM control device, although elemental mercury
is more difficult to adsorb onto solid surfaces than are the divalent
forms of mercury. Bituminous coals contain higher concentrations of
chlorine and other constituents that promote the oxidation and capture
of mercury in conventional air pollution control devices. In contrast,
flue gas from the combustion of subbituminous and lignite coals
typically have higher amounts of the more difficult to control
elemental form of mercury.
The available data indicate that installation of low-NOX
burners and

[[Page 79829]]

other combustion modification methods in pulverized coal-fired units
may increase the carbon content of the fly ash. Mercury emissions may
then be reduced through adsorption onto the fly ash carbon and
subsequent capture in the PM control device. The improved mercury
capture may come at the expense of slightly higher emissions of organic
HAP. Cyclone-fired units emit low amounts of fly ash and reduce the
chances of mercury adsorption and capture as particle-bound mercury.
Fluidized bed combustion systems typically have high flue gas
concentrations of high carbon-content fly ash and high levels of
mercury capture in PM emission control devices.
Electrostatic precipitators and FF generally remove greater than 90
percent of all trace metallic HAP, with the exception of mercury. They
are not effective in reducing emissions of gas-phase HAP, which include
trace organic HAP and HAP such as hydrogen chloride and hydrogen
fluoride.
Mechanical collectors and wet PM scrubbers are not generally
effective in reducing HAP emissions. Mechanical collectors capture only
HAP that are associated with large particles; fine-particle HAP and
gas-phase HAP pass through and are emitted to the atmosphere. Wet PM
scrubbers are moderately effective in reducing water-soluble HAP but do
not effectively reduce HAP emissions associated with fine particulate
or hydrophobic volatile organic HAP.
Dry scrubbers which employ a spray dryer adsorber (SDA) in
conjunction with an ESP or FF are typically very effective in reducing
HAP emissions. In SDA systems, water containing an acid gas sorbent is
sprayed into a reaction vessel where the acid gases and other
pollutants are reacted to form solid particles that can be collected in
a downstream PM control device. Some coal-fired utilities that use
bituminous coal in pulverized coal-fired units have shown mercury
capture in excess of 90 percent in SDA/FF systems.
Wet FGD systems are capable of capturing nearly all HAP other than
mercury and more than 90 percent of the divalent and particle bound
mercury. Mercury removal in wet FGD systems may range from less than 20
to more then 80 percent, depending on the type of coal and combustion
system used. Mercury capture in such units can be improved by the use
of catalysts or reagents to increase the conversion of elemental
mercury to soluble divalent forms of mercury.
Recent research indicates that mercury removal may be enhanced
through the use of oxidizing agents (that convert elemental mercury to
the ionized form) or through the use of sorbents (that adsorb the
mercury onto solid particles). Enhanced mercury removal may also be
achieved through greater use of multipollutant control options. Recent
data indicate that the use of selective catalytic or noncatalytic
reduction for NOX control may also oxidize mercury and,
therefore, enhance mercury control.
Thus, EPA's analysis of potential HAP control strategies allows EPA
to conclude that, during the regulatory development process, effective
controls for mercury and other HAP can be shown to be feasible.

D. Conclusions

The following conclusions summarize those presented in the utility
RTC and those based on the information subsequently obtained and are
based on the currently available scientific data. The conclusions, as a
whole, support a finding that regulation of coal-and oil-fired electric
utility steam generating units for HAP is appropriate and necessary.
1. Fossil fuel-fired electric utility steam generating units (coal-
and oil-fired units in particular) emit a significant number of the 188
HAP included on the section 112(b) list. Estimated growth in the number
of, and fuel use by, electric utility steam generating units
(particularly coal-fired units) during the period 1990 to 2010 will
result in an overall increase in HAP emissions. The new data gathered
to date corroborate the previous nationwide mercury emissions estimate
and confirm that electric utility steam generating units are the
largest anthropogenic source of mercury in the U.S.
2. Mercury is highly toxic, persistent, and bioaccumulates in the
food chain. Mercury emissions are transported through the atmosphere
and eventually deposit onto land or water bodies. The deposition can
occur locally near the source or at long distances (e.g., hundreds or
thousands of miles away). The air transport and deposition patterns of
mercury emissions depend on various factors, including: The form of
mercury released (divalent mercury deposits nearer to the source
whereas elemental mercury enters the global pool and deposits farther
from the source); the stack height and meteorology; and chemical
transformations during transport in the atmosphere. Once deposited, the
chemical form of mercury can change into methylmercury (through a
methylation process), which is a more toxic form that biomagnifies up
the aquatic food chain. Fish consumption dominates the pathway for
human and wildlife exposure to mercury. There is a plausible link
between emissions of mercury from anthropogenic sources (including
coal-fired electric utility units) and methylmercury in fish.
3. Neurotoxicity is the health effect of greatest concern with
methylmercury exposure. Methylmercury has a relatively long half-life
in the human body (averaging about 70 to 80 days). Dietary
methylmercury is almost completely absorbed into the blood and
distributed to all tissues including the brain; it also readily passes
through the placenta to the fetus and fetal brain. The developing fetus
is considered most sensitive to the effects from methylmercury;
therefore, women of childbearing age are the population of greatest
concern. Offspring born of women exposed to relatively high levels of
methylmercury during pregnancy have exhibited a variety of
developmental neurological abnormalities, including delayed
developmental milestones, cerebral palsy, and reduced neurological test
scores. Studies suggest that far lower levels of in utero exposures
have resulted in delays and deficits in learning abilities. It is also
possible that children exposed after birth are also potentially more
sensitive to the toxic effects of methylmercury than adults because
their nervous systems are still developing.
4. Extrapolating from high-dose exposure incidents, the EPA derived
an RfD for methylmercury of 0.1 ug/kg/day based on developmental
neurological effects observed in children born to mothers exposed to
methylmercury during their pregnancy. The NAS study determined that
EPA's RfD is a scientifically justifiable level for the protection of
public health. At the RfD or below, exposures are expected to be safe.
The risks following exposures above the RfD are uncertain, but risk
increases as exposures to methylmercury increase.
5. The results of recent dietary surveys indicate that most of the
U.S. population consumes fish and is exposed to methylmercury as a
result. Based on the surveys, about 85 percent of adults in the U.S.
consume fish at least once a month, about 40 percent of adults consume
fish once a week, and 1 to 2 percent of adults consume fish almost
daily.
6. The EPA estimates that about 7 percent of women of childbearing
age (i.e., between the ages of 15 and 44 years) are exposed to
methylmercury at levels exceeding the RfD and about 1

[[Page 79830]]

percent of women have methylmercury exposures 3 to 4 times that level.
7. Exposure to methylmercury can have serious toxicologic effects
on wildlife as well as on humans. Adverse effects to avian species and
wildlife have been observed in laboratory studies at levels
corresponding to fish tissue methylmercury concentrations that are
exceeded by a significant percentage of fish sampled in lake surveys.
Generally, wildlife consume fish from a much more limited geographic
area than do humans which can result in elevated levels of mercury in
certain fish-eating species in localized geographic areas. Those
species can include kingfisher, river otter, racoon, loon, as well as
some endangered species such as the Florida panther.
8. The EPA predicts that increased mercury deposition will lead to
increased levels of methylmercury in fish, and that increased levels in
fish will lead to toxicity in fish-eating birds and mammals, including
humans. The NAS, in its July 2000 report, stated that ``because of the
beneficial effects of fish consumption, the long-term goal needs to be
a reduction in the concentrations of methylmercury in fish.'' The EPA
agrees with that goal and believes that reducing emissions of mercury
from electric utility steam generating units is an important step
toward achieving the goal.
9. There are a number of alternative control strategies that are
effective in controlling some of the HAP emitted from electric utility
steam generating units. Recent data indicate that mercury, perhaps the
hardest HAP to remove from the exhaust gas stream, can be effectively
removed by using oxidizing agents or sorbents injected into the gas
stream. Recent data also indicate the possibility for multipollutant
control with other pollutants (e.g., NOX, SO2,
and PM), greatly reducing mercury control costs.

III. What Is EPA's Regulatory Finding?

Based on the results of the study documented in the utility RTC, as
well as subsequent analyses and other available information, the
Administrator has concluded that mercury is both a public health
concern and a concern in the environment. The Administrator has
concluded that there is a plausible link between methylmercury
concentrations in fish and mercury emissions from coal-fired electric
utility steam generating units. Although the degree to which that
linkage occurs cannot be estimated quantitatively now, the facts are
that: There is a linkage between coal consumption and mercury
emissions; electric utility steam generating units are the largest
domestic source of mercury emissions; and certain segments of the U.S.
population (i.e., the developing fetus, subsistence fish-eating
populations) are believed to be at potential risk of adverse health
effects due to mercury exposures resulting from consumption of
contaminated fish. Further, there remain uncertainties regarding the
extent of the public health impact from HAP emissions from oil-fired
electric utility steam generating units. Those facts and uncertainties
lead the Administrator to find that regulation of HAP emissions from
coal- and oil-fired electric utility steam generating units under
section 112 is appropriate and necessary. It is appropriate to regulate
HAP emissions from coal- and oil-fired electric utility steam
generating units under section 112 of the CAA because, as documented in
the utility RTC and stated above, electric utility steam generating
units are the largest domestic source of mercury emissions, and mercury
in the environment presents significant hazards to public health and
the environment. The NAS study confirms that mercury in the environment
presents significant hazards to public health. Further, it is
appropriate to regulate HAP emissions from such units because EPA has
identified a number of control options which EPA anticipates will
effectively reduce HAP emissions from such units. It is necessary to
regulate HAP emissions from coal- and oil-fired electric utility steam
generating units under section 112 of the CAA because the
implementation of other requirements under the CAA will not adequately
address the serious public health and environmental hazards arising
from such emissions identified in the utility RTC and confirmed by the
NAS study, and which section 112 is intended to address. Therefore, the
EPA is adding coal- and oil-fired electric utility steam generating
units to the list of source categories under section 112(c) of the CAA.
As a part of developing a regulation, the effectiveness and costs of
controls will be examined along with the level(s) of control that may
be technically feasible.
In developing a regulation under section 112(d), the statute
authorizes EPA to consider subcategorization of a source category. The
emissions standard for existing sources cannot be less stringent than
the average emissions limitation achieved by the best performing 12
percent of existing sources in the category or subcategory (the
``floor''). However, the EPA intends to develop a record to facilitate
consideration of subcategorization of the source category in setting
the ``floor.'' Based on the information that EPA has to date, the EPA
anticipates that a factual record will allow EPA to propose appropriate
subcategories for this source category. In developing standards under
section 112(d) to date, the EPA has based subcategorization on
considerations such as: the size of a facility; the type of fuel used
at the facility; and the plant type. The EPA also may consider other
relevant factors such as geographic conditions in establishing
subcategories. Once the source category is divided into subcategories,
the EPA determines the ``floor'' for each subcategory and, in turn, the
emissions standard independently for each subcategory. This approach
has helped build flexibility in meeting environmental objectives in the
past.
Once the floor is determined, the EPA can set an emissions standard
that is more stringent than the floor if a tighter level of control is
technically achievable and is justified. Factors that must be
considered in deciding whether a more stringent standard than the floor
is justified include: the cost of a more stringent standard; the energy
requirements; and any non-air quality health and environmental factors.
Every source has to meet the level of a standard set under section
112(d), but not necessarily every individual unit at a source. Most
electric generating plants have several units and so in meeting the
standard there may be opportunity for lower cost solutions because the
law allows for differences in reductions among units as long as the
source as a whole is in compliance.
There is considerable interest in an approach to mercury regulation
for power plants that would incorporate economic incentives such as
emissions trading. Such an approach can reduce the cost of pollution
controls by allowing for least-cost solutions among a universe of
facilities that face different control costs. Trading also can allow
for a greater level of control overall because it offers the
opportunity for greater efficiency in achieving control. The EPA,
however, recognizes and shares concerns about the local impacts of
mercury emissions and any regulatory scheme for mercury that
incorporates trading or other approaches that involve economic
incentives must be constructed in a way that assures that communities
near the sources of emissions are adequately protected. Thus, in
developing a standard for utilities, the EPA should consider the legal
potential for, and the economic effects of, incorporating a trading
regime

[[Page 79831]]

under section 112 in a manner that protects local populations.
The Administrator finds that regulation of HAP emissions from
natural gas-fired electric utility steam generating units is not
appropriate or necessary because the impacts due to HAP emissions from
such units are negligible based on the results of the study documented
in the utility RTC.
The EPA has previously indicated that it construes the term
``electric utility steam generating unit,'' as defined in section
112(a)(8) of the CAA and 40 CFR 63.41, to exclude all stationary
combustion turbines, regardless of whether such turbines are used to
generate electricity or used by an electric utility, and regardless of
whether such turbines are used in conjunction with waste heat recovery
units (65 FR 34010). Therefore, the finding concerning natural-gas
fired electric utility steam generating units does not apply to
stationary combustion turbines.

IV. Is This Action Subject to Judicial Review?

Today's finding that it is appropriate and necessary to regulate
coal-and oil-fired electric utility steam generating units adds these
units to the list of source categories under section 112(c). Section
112(e)(4) of the CAA states that, notwithstanding section 307 of the
CAA, no action of the Administrator listing a source category or
subcategory under section 112(c) shall be a final EPA action subject to
judicial review, except that any such action may be reviewed under
section 307 when the Administrator issues emissions standards for such
pollutant or category. Therefore, today's finding is not subject to
judicial review. As specified by section 112(e)(4), judicial review
would be available on both the listing decision and the subsequent
regulation at the time that such final regulation is promulgated. At
such time, the exact dimensions of the source category and the nature
of the control required would be sufficiently clear to allow for
judicial review.

V. Is EPA Asking for Public Comment?

The EPA has held several public meetings wherein oral and written
public input were solicited and obtained regarding the regulatory
finding. In addition, numerous opportunities for written comment
relating to both the study and the regulatory finding have been
provided. The EPA has decided that it is unnecessary to solicit
additional public comment on today's finding. The regulation developed
subsequent to the finding will be subject to public review and comment.

VI. Administrative Requirements

Today's notice does not impose regulatory requirements or costs.
Therefore, the requirements of Executive Order 13045 (Protection of
Children from Environmental Health Risks and Safety Risks), Executive
Order 13084 (Consultation and Coordination with Indian Tribal
Governments), Executive Order 13132 (Federalism), the Regulatory
Flexibility Act, the National Technology Transfer and Advancement Act,
and the Unfunded Mandates Reform Act do not apply to today's notice.
Also, this notice does not contain any information collection
requirements and, therefore, is not subject to the Paperwork Reduction
Act, 44 U.S.C. 3501 et seq. This notice was reviewed by the Office of
Management and Budget under Executive Order 12866 (58 FR 51735, October
4, 1993).

Dated: December 14, 2000.
Carol M. Browner,
Administrator.
[FR Doc. 00-32395 Filed 12-19-00; 8:45 am]
BILLING CODE 6560-50-U

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Regulatory Finding on the Emissions of Hazardous Air Pollutants From Electric Utility Steam Generating Units

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