United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-453/R-93-051a
November 1993
Air
& EPA
Study of Hazardous Air Pollutant and
Mercury Emissions from^Electric Utility
Steam Generating Units Pursuant to
Section 112(n) of the Clean Air Act
Amendments of 1990 -- Interim Report
to Congress
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November 1993
Electric Utility Steam Generating Unit
Hazardous Air Pollutant and Mercury Emission Study
Interim Report to Congress
Pursuant to the
Clean Air Act Amendments of 1990
Prepared by
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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TABLE OF CONTENTS
Section Page
1 INTRODUCTION 1
2 SCHEDULE 3
2 .1 UTILITY HAP STUDY 3
2.2 MERCURY STUDY 4
3 STATUS AND ACTIVITIES 10
3.1 COORDINATION WITH OTHER INTERESTED PARTIES . 10
3.2 DATA ANALYSIS 10
3.3 DATA ACQUISITION 11
3.3.1 LITERATURE DATA 11
3.3.2 FIELD SAMPLING 11
3.3.3 FUEL ANALYSES 13
3.3.4 ONGOING ACTIVITIES 14
3.4 MERCURY CONTROL 15
3 .5 UTILITY ACID RAIN COMPLIANCE PLANS 15
3.6 RADIONUCLIDES 15
4 PROJECTED ACTIVITIES 17
4.1 DATA ACQUISITION 17
4.2 HEALTH HAZARD ASSESSMENT 17
4.2.1 EXPOSURE AND RISK ASSESSMENT TOOLS . 18
4.2.2 HEALTH ASSESSMENT GOALS 19
4.3 REPORT TO CONGRESS 19
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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LIST OF TABLES
Page
SCHEDULE OF ACCOMPLISHED TASKS FOR ELECTRIC
UTILITY AIR TOXICS REPORT TO CONGRESS . . .
2-2 SCHEDULE OF PROJECTED TASKS FOR ELECTRIC UTILITY
AIR TOXICS REPORT TO CONGRESS
4-1 DRAFT OUTLINE FOR ELECTRIC UTILITY AIR TOXICS
REPORT TO CONGRESS 20
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1. INTRODUCTION
This interim report to Congress is in response to section
112(n) of the 1990 Amendments to the Clean Air Act (the Act).
Its purpose is to present to Congress a discussion of the
activities to date and the planned activities that will lead to
the submittal to Congress of the study of electric utility
emissions.
Section 112(n)(1)(A) mandates that the EPA perform a study,
to be presented in a Report to Congress, of the hazards to public
health reasonably anticipated to occur as a result of emissions
of the hazardous air pollutants (HAPs), listed under section
112(b), by fossil fuel-fired electric utility steam generating
units, after imposition of the requirements of the 1990
Amendments. The EPA is to develop and describe alternative
control strategies for HAPs which may warrant regulation under
section 112. If the EPA finds that regulation is appropriate and
necessary after considering the results of the study, it shall
then proceed with rulemaking activities under authority of
section 112. The EPA intends to announce its regulatory
determination in the final report of the study. The section
112(n)(1)(A) study is referred to as the "utility HAP study."
In addition, section 112(n)(1)(B) requires the EPA to
conduct, and transmit to the Congress, a study of mercury
emissions from electric utility units (and other sources of
mercury). The study shall consider the rate and mass of
emissions, the health and environmental effects of emissions,
technologies available to control emissions, and the costs of
control. This study is referred to as the "mercury study."
Since mercury is one of the HAPs listed in section 112(b), it and
the utility industry are covered under both sections 112(n)(1)(A)
and (B).
For the purposes of section 112, an electric utility steam
generating unit is any coal-, oil-, or natural gas-fired
combustion unit of more than 25 megawatts electrical output
capacity that serves a generator that produces electricity for
sale. A unit that cogenerates steam and electricity and supplies
more than one-third of its potential electric output capacity and
more than 25 megawatts electrical output to any utility power
distribution system for sale is also considered to be an electric
utility steam generating unit. Thus, the industry being studied
includes both the traditional electric utility industry as well
as certain industrial and third-party units that cogenerate steam
and electricity.
The results of the study required under section 112(n)(1)(A)
are directed to be presented to Congress by November 15, 1993,
while the results of the study required under section
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112(n)(1)(B) are directed to be presented by November 15, 1994.
However, as discussed below, the results of the utility HAP study
will be transmitted to Congress in November 1995 along with an
update of the utility portion of the previously submitted mercury
study. The delay is necessary to allow the Agency the time to
acquire sufficient valid HAP emissions data upon which to base a
credible health hazard assessment. This interim report explains
the basis for the schedule delay for completion of the utility
HAP study as well as describing the activities completed and
underway to provide the final report of the study by November 15,
1995.
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2. SCHEDULE
2.1 Utility HAP Study
In section 112(n)(1)(A), Congress directed that the utility
HAP study be presented by November 15, 1993. Initial studies by
the EPA indicated that very little documented data were available
on HAP emissions from electric utility steam generating units,
and measurement methods needed to be further developed or refined
for characterizing many of the HAPs. In short, it did not appear
that the available data were sufficient to provide the basis for
a credible health hazard assessment of HAP emissions from
electric utility steam generating units.
Much of the data on non-radionuclide HAPs available through
the literature had been gathered over a broad time period using a
wide variety of dated, and sometimes ill-defined, sampling and
analytical techniques. Many of these techniques, including the
method for mercury, have since been replaced with more accurate
methods. The available data exhibit extensive variability in the
reported concentrations of HAPs in emissions (sometimes varying
by several orders of magnitude) which can, in turn, significantly
skew the calculated emission rates. Often, there is insufficient
description or documentation of the techniques and assumptions
used to be able to sort the reliable from the unreliable data.
In addition, much of this available data was gathered at
laboratory or pilot scale installations or from utility units
that did not reflect the configuration of the current electric
utility steam generating unit population. Again, there was often
insufficient documentation of the design parameters or process
operating conditions to assess the validity of the data or the
impact of the process operating conditions on the non-
radionuclide HAP emissions.
The requested timing of the study was believed to have been
chosen assuming the existing information would be adequate rather
than accounting for the time required for researching methods for
measuring HAPs, generating new field data on the presence and
quantities of HAPs in emissions from representative electric
utility steam generating units, and further developing
methodologies for assessing the hazards to public health.
However, even with the full participation of the EPA, other
Federal agencies such as the Department of Energy (DOE), State
and local air pollution control agencies, and the industry, it
became clear early in the study that preparation of a
sufficiently definitive and scientifically defensible study,
using the existing data base, could not be accomplished within
the 3 years specified in the 1990 Amendments.
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Thus, in October 1991, in response to a Congressional
inquiry, the EPA indicated that the utility HAP study would be
performed on the same schedule as the mercury study (i.e.,
submittal by November 15, 1994) . To meet this revised schedule,
all data on the emissions of HAPs and the characterization of the
types of facilities in the utility industry would have had to be
compiled by January 1993 for the health hazard assessment
component of the study to be performed on schedule. In October
1991, the Agency believed this to be a realistic revision to the
schedule.
However, through its review of the existing data base, the
Agency became aware of major problem areas in the data and of the
existence of an extensive HAP field sampling program underway by
the industry. This effort was primarily through the Electric
Power Research Institute (EPRI) and the Utility Air Regulatory
Group (UARG), but also by individual electric utility companies.
In addition, the DOE was about to embark on a similar program,
albeit on a smaller scale. These programs include field sampling
for 25 to 30 of the 189 HAPs at 25 to 30 fossil fuel-fired
electric utility steam generating units using the best accepted
sampling and analytical methods. In the absence of these data,
the Agency would be basing its assessment on data that were much
more limited in nature and quality. The Agency, therefore,
determined that an additional 1-year delay would be necessary.
These programs, and the impact of their timing on the schedule
for the utility toxics study, will be discussed further below.
Table 2-1 presents a list of accomplished milestone dates
for the utility HAP study. Table 2-2 presents a list of those
milestones necessary to complete the study by November 1995.
2.2 Mercury Study
The mercury study required under section 112(n)(1)(B) is
directed to be submitted to Congress in November 1994. The
relationships between the two studies for the electric utility
industry are discussed below.
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Table 2-1. Schedule of Accomplished Tasks for Electric
Utility Air Toxics Report to Congress
EPA Initiates Utility HAP Study
General HAP Workshop with EPRI/DOE/UARG
General HAP Workshop with EPRI/DOE/UARG
Contractor Support Effort Initiated on
Utility HAP Study
General HAP Workshop with EPRI/DOE/UARG
HAP Emission Testing Workshop with
EPRI/DOE/UARG
Draft Outline for Report to Congress
Draft Matrix of Utility Industry
HAP Health Hazard Assessment Workshop with
EPRI
General HAP Workshop with EPRI/DOE/UARG
Complete Data Base of Utility Plant
Parameters
Meeting with National Coal Association
HAP Emission Source Test Requests (2)
Completed for EPA FTIR Tests
Summary of Existing HAP Data Bases
EPA Work Group Meeting - Project Approach
HAP Emission Testing Workshop with
EPRI/DOE
Non-EPRI Industry HAP Emission Test
Reports (10) Received
Interim HAP Emission Test Reports (3)
Received from EPRI/UARG
HAP Health Hazard Assessment Workshop with
EPRI
t
General HAP Workshop with EPRI/DOE/UARG
October 1. 1990
May 31. 1991
October 18. 1991
November 27. 1991
February 19. 1992
February 19. 1992
March 20. 1992
March 20. 1992
April 28. 1992
May 21. 1992
May 29. 1992
June 8_u 1992
July 10. 1992
July 21. 1992
July 30. 1992
August 18. 1992
August 20. 1992
October 20. 1992
October 22. 1992
October 23. 1992
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HAP Emission Source Test Requests (3)
Completed for EPA FTIR Tests
Site Visit to Potential EPA FTIR HAP
Emission Test Site
Receive USGS Data Base of Coal HAP
Concentrations
Interim HAP Emission Test Reports (2)
Received from EPRI/UARG
Draft Analysis of USGS Coal Data for HAP
Concentrations
Request for Additional Information on EPRI
HAP Emission Test Reports
Preliminary HAP Data Summary Submitted for
Health Hazard Assessment De-bugging
Interim HAP Emission Test Reports (2)
Received from EPRI/UARG
General HAP Workshop With EPRI/DOE/UARG
Contractor Support Effort Initiated on
Mercury Control Costs
Interim HAP Emission Test Reports (7)
Received from EPRI/UARG
Draft Chapter 3
Site Visit to Three Potential EPA FTIR HAP
Emission Test Sites
DOE HAP Emission Test Kick-off Meeting
Draft Analysis of Fuel Switching on Coal-
based HAP Emissions
Draft Chapter 6
Receive Data Base of Cogeneration Plant
Parameters
Interim HAP Emission Test Reports (2)
Received from EPRI/UARG
t
EPA FTIR HAP Emission Tests (3)
November 13, 1992
December 1. 1992
December 11. 1992
December 17. 1992
December 29. 1992
February 11, 1993
February 19. 1993
February 22, 1993
February 23. JL!
March 4^.
March 12. 1993
March 30. 1993
April JL_ 1993
April 14. 1993
April 20. 1993
April 29. 1993
April 30. 1993
May 3_,_ 1993
May 21. 1993
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Draft Chapter 2
EPA FTIR HAP Emission Tests (2)
Interim HAP Emission Test Report (1)
Received from EPRI/UARG
General HAP Workshop with EPRI/DOE/UARG
Final Set, Interim HAP Emission Test
Results from EPRI/UARG
Complete Control Costs and Impacts for
Mercury Control
Submit Interim Report to Congress
General HAP Workshop with EPRI/DOE/UARG
June 30. 1993
July 30. 1993
August 17. 1993
August 26. 1993
September 1. 1993
September 30. 1993
November 15. 1993
December 21. 1993
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Table 2-2. Schedule of Projected Tasks for Electric
Utility Air Toxics Report to Congress
Final HAP Emission Test Reports from
EPRI/DOE
EPA Summary Emission Test Report (5 tests)
Initiate Health Hazard Assessment
EPA Final HAP Emission Test Reports
Draft Chapter 4
EPRI Synthesis Report
EPA Work Group Meeting - HAP Emission Test
Results
Radionuclide Analyses Component of Health
Hazard Assessment Complete
Revised Draft Chapter 6
Draft Chapter 7
Complete Final Draft Health Hazard
Assessment
Draft Report (w/o Appendices) to EPA
Internal Peer Review
EPA Work Group Meeting - Health Hazard
Assessment
Draft Report (w/o Appendices) for
Industry/Outside Review
Draft Appendices
Industry/Outside Review Complete
EPA Work Group Meeting - Review Comments
Draft Chapter 1
Appendices Complete
Report to Congress 'Revisions Complete
EPA Work Group Closure
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January 3 . 1994
January 3. 1994
March i_L. 1994
May 2j_ 1994
May 16. 1994
June 1. 1994
June 15. 1994
July
1994
August 15. 1994
September 1. 1994
October 3. 1994
October 17. 1994
November 1 . 1994
November 22. 1994
January 3. 1995
January 17. 1995
February 15. 1995
March JU 1995
March 15. 1995
March 15. 1995
May 15. 1995
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OAR Report Clearance June 1. 1995
Draft Final Report to EPA Office of July 3^ 1995
Congressional and Legislative Affairs
Draft Final Report to OMB July 17. 1995
OMB Review Complete October 16. 1995
Final Report to Administrator November 1. 1995
Final Report to Congress November 15. 1995
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3. STATUS AND ACTIVITIES
The activities being undertaken on the utility toxics study
are related to the acquisition of sufficient information to allow
the Agency to estimate HAP emissions from all electric utility
steam generating units and on the methods to use those data in
estimating the "hazards" to the public health. This section
presents the Agency approach to the development of the necessary
data and the coordination efforts that have been undertaken in
gathering the data.
3.1 Coordination With Other Interested Parties
In fiscal year (FY) 1991, the EPA joined with the EPRI, the
UARG, and the DOE in the first of a continuing series of
workshops for the purpose of exchanging information related to
air toxics activities, coordinating these activities, and
possibly co-funding of data gathering for the study. These
workshops have also recently included the Class of 85 Regulatory
Response Group, a voluntary, non-profit, group representing the
electric utility industry (similar to the UARG but representing
generally smaller oil- and gas-fired utilities).
Additional meetings have been held, on a smaller scale, to
discuss emission test and analysis methods, emission test method
validations, and approaches to be taken for the health hazard
assessment. An information meeting has also been held with the
National Coal Association to apprise them of the study and to
solicit information they may have regarding the trace metal
contents of coals and the effectiveness of HAP removal by coal
cleaning or washing.
3.2 Data Analysis
To determine the types of data that were needed, the
Agency's Emission Standards Division (ESD) assessed the data
necessary to perform the health hazard assessment and to develop
the control strategies requested by Congress. The health hazard
assessment will be performed based on analyses of the impact of
estimated HAP emissions from each utility plant in the United
States. Therefore, data on emissions and/or other parameters for
each utility boiler was determined to be necessary. It was
recognized that HAP emissions data would not be available for
each facility. However, other plant-specific data were known to
exist, including boiler type, fuel type and source, emission
controls in place, and plant location and stack dimensions.
To utilize the data to be acquired, the EPA has developed a
computer program that will analyze information on individual coal
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HAP contents and HAP emissions data from the tested units to
provide a calculated HAP emission factor for each utility boiler
in the United States. The computer program will allow the coal
characteristics for the specified utility to be input along with
the removal abilities of the controls in use, based on emission
test data, to arrive at an emission rate (factor) for each
individual boiler. Changes in control methodologies can also be
altered for each utility boiler, based on announced or projected
Phase I and II compliance plans. This emission factor will then
be used in the modeling for the health hazard assessment.
Electric utility plans for compliance with Phases I and II
of title IV were also determined to be necessary. To determine
the potential control strategies for HAP emissions control, the
effectiveness of existing and near-term future controls was also
determined to be necessary, based on actual HAP emissions data
from the electric utility industry. It was established that
these types of data were not available in the existing literature
data base.
3.3 Data Acquisition
3.3.1 Literature Data
The BSD has conducted a literature search of available non-
radionuclide HAP emission and control information and assessed
the usefulness of these data. As noted above, essentially all of
these data were found to be unusable for the necessary analyses,
particularly due to deficiencies in emission test methodology,
documentation of process operation, or other documentation.
These deficiencies were such that the Agency would not be able to
utilize the data in control strategy analysis or to project the
data for nationwide application in the health hazard assessment.
Industry data on the types of boilers, fuels, and controls
were obtained to ensure adequate coverage during the field
sampling and the data analyses phases (i.e., HAP emissions data
would be gathered in such a manner that the majority of
boiler/fuel/control configurations could be addressed). This
data base provides the necessary plant-specific information to
conduct the health hazard assessment and the control strategy
analyses.
3.3.2 Field Sampling
To obtain the necessary non-radionuclide HAP emission test
data, two avenues were pursued. The first was to tap into the
industry and DOE programs while the second involved Agency
testing for HAP organics.
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The EPRI has a program underway whereby they will sample air
emissions at 20 to 25 of their member electric utility facilities
for approximately 25 of the 189 HAPs listed in section 112(b).
This program was initiated in mid-1990 but did not get into full
operation until mid-1991, with most of the data expected to be
available by January 1994. The Agency became aware of the extent
of the program at the October 1991 workshop meeting and of the
schedule at the February 1992 workshop meeting. The program was
of such complexity that schedule acceleration by EPRI was not
possible.
These tests will encompass firing of coal, oil, and natural
gas with a variety of boiler firing types and particulate matter
and sulfur dioxide (S02) emission control technologies. Emission
test sites were selected based on a number of criteria (including
the facilities willingness to cooperate). The various types of
boilers, fuels, and controls were aggregated into a summary table
(matrix). Site selection was based primarily on the unit's
position in the overall matrix of utility boilers. The EPRI then
selected categories of plants based on industry utilization
(e.g., the largest percentage of coal-fired units are dry bottom,
use bituminous coal, and have no emission controls except for
electrostatic precipitators for particulate matter), followed by
selection of individual sites within a given category. This
approach allows for acquisition of data for the broadest spectrum
of the utility industry in the most cost effective manner. Some
of the EPRI emission test sites are DOE Clean Coal Technology
(CCT) sites which provide for the acquisition of HAP data before
and after installation of controls for nitrogen oxides (NOJ ,
another important element in the acid rain program. Samples are
being collected before and after each emission control device
where feasible.
The DOE, through its Pittsburgh Energy Technology Center
(PETC), initiated contract activities in mid-1992 for a HAP
emission sampling program at eight coal-fired electric utility
steam generating units. The contracts were awarded in early 1993
and the sampling was completed over the period June to August
1993. The DOE program is similar in nature and scope to that of
EPRI. Although the number of facilities being evaluated is much
smaller under the DOE program, the timing was such that the data
are to be available in the same time frame as those from the EPRI
program, and, thus, will be included in the utility toxics study.
The EPA is providing funding for quality assurance/quality
control (QA/QC) activities on the DOE program.
For both of these field test programs, the EPA has been
involved with the design of the program and in the selection of
emission test and analysis methods. Several meetings have been
held among the parlfies involved to discuss the appropriate
methods and the impacts of any deviations or interferrents. The
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Agency has also co-funded with the EPRI a field validation of
several mercury emission test methods at a coal-fired utility
boiler, including those methods that can measure the various
species of mercury that may be emitted from an electric utility
boiler.
For the EPRI program, the Agency independently developed a
matrix of the industry and established that the types of plants
selected for the EPRI program were the same types that would have
been selected for an EPA emission test program. For the DOE
program, the Agency had the opportunity to provide input into the
type of plant that should be selected.
Individual members of the electric utility industry are also
involved in the acquisition of field HAP emission data. The EPA
is actively obtaining these data for use in the study. For all
emission test reports received (EPRI, DOE, and individual company
submittals), the EPA is reviewing the reports for completeness,
adherence to accepted sampling and analytical techniques, and
proper unit operation (the very information that is missing from
the existing literature-based data base). Where necessary,
additional information has been requested from the tested
site (s).
The EPA has also completed the initial development of the
Fourier transform infrared spectrometry (FTIR) field testing
system and system validation for real-time, simultaneous
measurement of approximately 120 gaseous organic HAPs.
Validation tests for the FTIR at a coal-fired unit were conducted
in February 1993. The FTIR system is promising as a lower cost
and much more flexible measurement technology than those
currently available for both utility boilers and other sources of
air toxics under section 112 of the Act.
The EPA has conducted field emission tests using the FTIR
system at five electric utility steam generating units (one
pulverized coal [PC]-fired boiler, one coal-fired fluidized bed
combustion [FBC] boiler, one oil-fired boiler, one gas-fired
boiler, and one gas-fired combined cycle combustion turbine).
These tests will provide data on organic HAP emissions,
augmenting the trace metal data being acquired by the industry.
These tests were completed in July 1993 and the results are
expected by the end of calendar year 1993.
3.3.3 Fuel Analyses
The EPA obtained from the U.S. Geological Survey (USGS) a
study of the occurrence of trace metals in economically
recoverable U.S. coals. The purpose of this study was two-fold.
First, the issue of fuel switching (i.e., to a coal having a
relatively lower sulfur content) as an acid rain compliance
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strategy has already raised questions as to its impact on HAP
emissions. The second purpose was to provide a data base of coal
trace metal contents for input into the computer program noted
earlier. Information of a similar nature has been requested from
the NCA and individual companies, along with information relating
to the impact on trace metal concentrations of coal washing or
cleaning. A limited amount of information has been obtained.
Contact has also been made with the American Gas Association
(AGA) and the Gas Research Institute (GRI) to obtain information
as to the trace metal contents of the natural gas utilized in
U.S. electric steam generating units. Attempts have also been
made to obtain the trace metal content of fuel oils used by the
utility industry.
3.3.4 Ongoing Activities
In addition to the data acquisition activities discussed
above, it should be noted that considerable research into the
generation and control of HAP emissions from electric utility
steam generating units is being conducted by interested parties
(including the Agency, the DOE, the coal companies, and the
industry). This work has been initiated over the past few years
and will continue for several years. For example, for Rounds IV
and V of the DOE CCT program, HAP testing similar to that
currently being done by EPRI and DOE/PETC will be performed.
Testing of this nature will also be retroactively done on a few
of the earlier CCT sites. The DOE/PETC will also undertake a
Phase II testing program on additional coal-fired boilers similar
to the work now underway. However, these data will not be
available for several years.
Furthermore, pilot-scale work is being conducted on the
impact of boiler process conditions on HAP emissions. Sorbents
in combination with, or in addition to, carbon are being
investigated for trace metal removal capabilities. Work is
ongoing on how conventional coal cleaning may be modified to
improve trace metal removals in addition to providing suitable
ash and sulfur removals and acceptable coal quality. Advanced
coal cleaning technologies are also being investigated for their
ability to remove trace metals.
These activities will provide valuable information that will
add to the knowledge related to utility boiler HAP emissions and
controls. However, little, if any, of the data will be available
for use in this study. While there may always be "one more piece
of information" relating to HAP emissions from utility boiler,
only that data available in time to meet the schedule noted in
section 2 will be used in the current analyses.
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3.4 Mercury Control
The EPA is following the work of EPRI and other industry and
commercial organizations on the use of activated carbon injection
for mercury control in utility boiler exhaust gas streams. This
control method has been shown to be very effective in removing
both mercury and dioxins/furans from municipal waste combustor
(MWC) and medical waste incinerator (MWI) exhaust gas streams but
has not been applied to electric utility steam generating units
in the United States. A combination of technology transfer from
MWCs and MWIs will be used along with input from the non-Agency
work in addressing the effectiveness of activated carbon
injection as a technology for reducing mercury emissions from
utility boilers.
As noted above, there is overlap between the utility HAP
study and the mercury study. The approach being taken on the
mercury study with regard to the electric utility industry is to
perform the analyses based on the assumption that all mercury
contained in the fuel is likely to be emitted to the atmosphere.
This assumption is grounded on the information in the available
literature and will allow the study to proceed, albeit based on a
potentially worst-case basis (i.e., no "credit" for mercury
removal during coal cleaning or by existing emission control
devices). The data being gathered as a part of the utility HAP
study will be used to assess the actual mercury control being
effected by coal cleaning and by current emission control
technologies and, thus, the utility HAP study will update the
mercury study with regard to these actual levels of control. The
health hazard assessment will reflect any reductions in mercury
emissions noted during the utility toxics study.
3.5 Utility Acid Rain Compliance Plans
The Agency is following announcements being made by the
industry regarding acid rain control strategies. This
information will be utilized to provide a "snapshot" of the
industry after compliance with the acid rain portions of the 1990
Amendments to determine any impact on HAP emissions. Computer
projections, based on economic models, of Phase II unit
compliance plans may also be utilized.
3.6 Radionuclides
The EPA has undertaken a comprehensive approach to assessing
the natural radionuclide content in coal, natural gas, and
residual fuel oil. This approach integrates data obtained from
(1) previous studies conducted by the EPA, (2) studies reported
in the scientific literature, and (3) data bases maintained by
the USGS and others.
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A national data base of coal samples has been analyzed with
regard to uranium and thorium content. The data base consists of
the results of analysis performed on nearly 7,000 coal samples
obtained over a period of 17 years from various mining regions of
the United States that supply the major ranks of coal used by
utilities. Additional radionuclide emissions data will be
provided by the DOE HAP emissions test program. Data from these
two sources will be used as input for the health hazard
assessment for coal-fired boilers.
Radioactivity in natural gas is almost exclusively confined
to radon-222. The radon content of natural gas at the well-head
has been documented for thousands of wells over several decades.
Due to the fact that radon concentrations are markedly reduced
when natural gas is processed, other studies have focused on
assessing radon concentrations in distribution lines. This
existing data base will be utilized in the health hazard
assessment for gas-fired units.
Documented studies employing non-radiometric analyses have
shown that crude oil and its derivatives may contain uranium a.nd
thorium. To supplement the available data for residual fuel oil,
the EPA requested that the EPRI/UARG solicit the voluntary
participation of utilities in sampling residual oil supplies.
The fuel stocks sampled were selected to be representative of the
oil combusted for electrical power generation. To ensure that
the samples provided by the utilities are representative of their
station inventory of fuel oil, utilities were provided specific
guidance for sample collection.
Accredited contract laboratories with the applicable
experience have been identified. Final selection of a laboratory
will be based on results reported in testing a "reference sample"
of residual fuel oil provided by the National Institute of
Standards and Technology (NIST). The EPA has entered into an
agreement with NIST to analyze a composite sample derived from
samples submitted by participating utilities.
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4. PROJECTED ACTIVITIES
4.1 Data Acquisition
The HAP emissions data from EPRI and DOE will be provided to
the Agency by January 1994. These data will be combined with
those from the EPA FTIR HAP emissions test program and other
industry organizations. The EPA will then perform the necessary
analyses of the data so that the emission factors can be
developed for each electric utility steam generating unit in the
United States for input into the health hazard assessment.
A parallel effort will be undertaken to establish the
various HAP emission control strategies available to the electric
utility industry. This activity will involve analysis of the
various combinations of HAP control measures available to the
electric utility industry and assessing their effectiveness.
4.2 Health Hazard Assessment
The EPA has developed several exposure and risk tools
(computer models) which are designed to quantify the potential
public exposure and health risks associated with a given source
or source category. Based on previous studies of the fossil-
fuel- fired utility plants, the EPA has identified three areas of
concern which these tools can address: 1) direct inhalation of
emissions by people living near the plant; 2) indirect exposure
(e.g., wet and dry deposition causing soil, water, and food
contamination) to emissions by people living near the plant; and
3) direct and indirect exposure to emissions from many plants by
people located at much greater distances from the plants (i.e.,
long-range transport).
The EPA plans to estimate direct inhalation exposure by
people living near each utility plant in the U.S. For the
indirect exposure analyses, the EPA plans a qualitative
evaluation of a number of model plants, which are representative
of this industry's plant characteristics, and use these results
to describe national-level impacts. For the long-range transport
and exposure calculations, the EPA plans to evaluate all the
plants by aggregating emissions and exposure impacts into
regional-sized cells. All of the above exposure evaluations will
be based on the emissions estimates as described in Section 3.2.
Finally, the model plants will be subjected to an
uncertainty analysis which will provide quantitative and
qualitative descriptions of the potential variations in the final
risk estimates. Tttis analysis will be based on the known
variations in the input data for the more significant factors
(e.g., emissions).
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At this time, the EPA is currently completing the details of
the study design, collecting the required data for the various
models, and conducting those parts of the utility-health-hazard-
assessment study which do not require the final emission
estimates, which will not be available until early 1994.
4.2.1 Exposure and Risk Assessment Tools
The EPA will use three computer models to conduct the above
analyses. A human exposure model will be used to estimate direct
inhalation exposure and risks to people living near each plant.
The exposure model has a state-of-the-science air dispersion
model, the best available meteorological data base, and the 1990
census data. The exposure model will evaluate all pollutants for
which the EPA has both reliable emissions data and a health
endpoint (e.g., cancer potency estimate). The indirect exposure
model includes a wet and dry deposition model, food ingestion
model, soil exposure model, and a water exposure model. Although
quantitative in nature, the goal of this effort is to
qualitatively describe the range of impacts that may occur from
indirect exposure. The long-range transport model conducts an
analysis based on a regional scale. For mercury, atmospheric
chemistry will be included in the long-range transport analysis;
for other pollutants, the EPA does not expect atmospheric
transformation to be significant or does not have enough data to
consider this effect. The indirect exposure and long-range
transport models will be used to evaluate a subset of pollutants
(approximately 6) which may create significant long-range impacts
and indirect exposures through persistence or bioaccumulation
(e.g., arsenic, lead, mercury, benzo-a-pyrene, dioxins, and
cadmium).
For carcinogens, risks will be estimated by applying cancer
potency estimates; in addition, for non-cancer effects, the EPA
will compare calculated ambient concentrations to inhalation
reference concentrations, which are estimates of a daily human
exposure that are likely to be without an appreciable risk of
deleterious effects during a lifetime.
The above models are not designed to evaluate radionuclide
emissions. Estimates of radionuclide emissions are based on a
model that accounts for site-to-site variability in emissions,
plant design features, and operating parameters. The exposure
and risk estimates will be added into the final risk assessment
results.
4.2.2 Health Assessment
By applying the computer tools described above, the EPA
expects to estimate a number of exposure and risk parameters.
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For exposure, the total number of people living near all the
plants will be estimated. Also, the maximum long-term air
concentrations to which someone is exposed will be calculated for
all pollutants with available emissions data.
For carcinogens, the risk due to the plants' emissions for
the most exposed individuals and the total number of average
annual cancer cases will be estimated for the U.S. These risks
will be based on evaluations of short- and long-range-direct
inhalation exposure. The indirect exposure analysis will provide
information from which the EPA can qualitatively describe the
potential range of additional risks that occur from non-
inhalation pathways. Unless there are data to indicate another
approach, the EPA plans to add cancer risks from all pollutants,
including radionuclides, to obtain the total risk estimates. For
non-cancer health effects, the maximum concentration from direct
inhalation and the number of people who are directly exposed to
concentrations above the inhalation reference concentration will
be estimated.
For those pollutants with no quantitative health benchmarks,
the EPA is considering several options, but has not decided how
to proceed. Most likely, the EPA will provide exposure and
health data summaries based on the available data and attempt to
determine qualitatively the likelihood of a potential health
problem.
4.3 Report to Congress
Once the health hazard assessment and control strategies
have been completed, they will be incorporated into the draft
utility HAP study Report to Congress. A draft of the outline
being used in preparing the Report is provided in Table 4.1.
This draft will be Agency peer reviewed and technically reviewed
by outside groups prior to being submitted for Agency approval.
The approved Report will be submitted to the Office of Management
and Budget (OMB) for review before being delivered to the
Congress.
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Chapter
Table 4-1 Draft Outline for Electric Utility
Air Toxics Report to Congress
I. Major Findings of Electric Utility Hazardous Air
Pollutant and Mercury Study
II. Introduction
III. Characterization of Electric Utility Steam Generating
Units
IV. Emissions Data Gathering and Analysis
V. Health Hazard Assessment
VI. Alternative Control Strategies for Hazardous Air
Pollutant Emissions Reduction
VII. Utility Update to Mercury Study
VIII. Appendices
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TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-453/R-93-051a
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
November 1993
Study of Hazardous Air Pollutant and Mercury Emissions from
Electric Utility Steam Generating Units Pursuant to Section
112(n) of the Clean Air Act Amendments of 1990 -- Interim
Report to Congress
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Emission Standards Division (MD-13)
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This interim report to Congress is in response to section 112(n) of the 1990 Amendments to the Clean
Air Act (the Act). Its purpose is to present to Congress a discussion of the activities to date and the
planned activities that will lead to the submittal to Congress of the study of electric utility hazardous air
pollutant (HAP) emissions. The results of the study required under section 112(n)(l)(A) are directed to
be presented to Congress by November 15, 1993. However, the results of the utility HAP study will be
transmitted to Congress in November 1995 along with an update of the utility portion of the previously
submitted mercury study. The delay is necessary to allow the Agency the time to acquire sufficient valid
HAP emissions data upon which to base a credible health hazard assessment. This interim report
explains the basis for the schedule delay for completion of the utility HAP study as well as describing
the activities completed and underway to provide the final report of the study to Congress by November
15, 1995.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Electric Utility Steam Generating Units
Hazardous Air Pollutants
Air Toxics
Air Pollution Control
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report)
Unclassified
21. NO. OF PAGES
20
20. SECURITY CLASS (Page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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