EPA-453/R-93-047
Source Category
Schedule for Standards:
Summary of Public Comments
| and Responses
V)
Emission Standards Division
. Office of Air Quality Planning and Standards
United States Environmental Protection Agency
Research Triangle Park, North Carolina 27711
U S Environmental Protection Agency
Region 5, Library (PL-12J) .
September 1993 77 West Jackson Boulevard, IZtn now
ruu,™ II 60604-3590
/ / VVC3L JSIW".**-"1 — '-~~
Chicago, IL 60604-3590
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DISCLAIMER
This report has been reviewed by the Emissions Standards
Division of the Office of Air Quality Planning and Standards,
Environmental Protection Agency, and approved for publication.
ention of trade names or commercial products is not intended
to constitute endorsement or recommendation for use. Copies
of this report are available through the Library Services
Office (MD-35), U- S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711, or from National
Techr ;al Informatic Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
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TABLE OF CONTENTS
LIST OF
TABLES
1.0 SUMMARY
2.0 SUMMARY OF PUBLIC COMMENTS
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
SOURCE CATEGORY DEFINITIONS
SECTION 112 (g)
SOURCE CATEGORY LIST
2.3.1 SOCMI Source Category
2.3.2 Lead Acid Battery Manufacturing Source
Category
2.3.3 Asbestos Processing Source Category . .
2.3.4 Stationary Internal Combustion Engines
and Stationary Turbines
SOURCE CATEGORY RANKING SYSTEM METHODOLOGY OR
APPROACH
2.4.1 General
2.4.2 Exposure Score
2.4.3 Health Effects Score
2.4.4 Environmental Effects
SCHEDULE AND RANKING FOR SPECIFIC SOURCE
CATEGORIES
FLEXIBILITY
EFFICIENCY OF GROUPING
OTHER SCHEDULING CONSIDERATIONS
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LIST OF TABLES
Page
2-1 LIST OF WRITTEN COMMENTERS ON THE PROPOSED SCHEDULE
FOR THE PROMULGATION OF EMISSION STANDARDS 2-2
IV
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1. 0 SUMMARY
A draft source category schedule for emission standards
was published in the Federal Register on September 24, 1992
(57 FR 44147). The schedule provided promulgation dates for
source categories to be regulated by the national emission
standards for hazardous air pollutants (NESHAP). The
publication was followed by a public comment period, which
concluded on October 26, 1992.
2.0 SUMMARY OF PUBLIC COMMENTS
A total of 18 letters commenting on the draft schedule
for the promulgation of emission standards were received.
Comments were provided by industry representatives and
government agencies.
These comments have been recorded and placed in the
docket for this schedule action (Docket No. A-91-14,
Category IV-D). Table 2-1 presents a listing of all persons
submitting written comments, their affiliation, and the EPA
docket item number assigned to their correspondence.
2.1 SOURCE CATEGORY DEFINITIONS
Comment: Five commenters (IV-D-1, IV-D-5, IV-D-8,
IV-D-9, IV-D-15) requested that the EPA provide additional
information with the source category schedule to assist
sources in determining into which source category their
sources might fall. These commenters contended that the
sources and hazardous air pollutants (HAP's) which will be
controlled in each of the categories were not well-defined in
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TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
SCHEDULE FOR THE PROMULGATION OF EMISSION
STANDARDS
Docket item number3 Commenter and affiliation
IV-D-1 Mr. M. L. Mullins
Vice President, Regulatory Affairs
Chemical Manufacturers Association
2501 M Street, NW
Washington, D.C. 20037
IV-D-2 Mr. David J. Hayes
Ms. Julia A. Hatcher
Counsel for the Semiconductor
Industry Association
Latham and Watkins
10O1 Pennsylvania Avenue, NW
Washington, D.C. 20004
IV-D-3 Mr. j. paige straley
Corporate Environmental Manager
Sandoz Chemicals Corporation
Post Office BOX 669246
Charlotte, North Carolina 28266
IV-D-4 Mr. Nicholas Anastas
Office of Research and Standards
Department of Environmental
Protection
Commonwealth of Massachusetts
One Winter Street
Boston, Massachusetts 02108 •
IV-D-5 Mr. J. C. Hovious
Assistant Director
Environmental Affairs
Union Carbide Corporation
39 Old Ridgebury Road
Danbury, Connecticut 06817-0001
IV-D-6 Mr. J. A. Dege
CAA Issue Manager
Dupont Chemicals
Wilmington, Delaware 19898
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TABLE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
SCHEDULE FOR THE PROMULGATION OF EMISSION
STANDARDS (CONTINUED)
Docket item number3 Commenter and affiliation
IV-D-7 Mr. Richard A. Bausell
Manager, Environmental Legislative
and Regulatory Affairs
Natural Gas Pipeline Company of
America
701 East 22nd Street
Lombard, Illinois 60148-5072
IV-D-8 Ms. Elizabeth Fisher
Manager, Air and EPCRA Programs
Rohm and Haas Company
Independence Mall West
Philadelphia, Pennsylvania 19105
IV-D-9 Mr. Robert F. Brothers
Director, Federal Government
Relations
Eastman Kodak Company
343 State Street
Rochester, New York 14650
IV-D-10 Ms. Cindy H. Evans
Associate Environmental Counsel
American Paper Institute, NFPA
1250 Connecticut Avenue, NW
Washington, D.C. 20036
IV-D-11 Mr. Kurt J. Olson
Counsel for the Battery
Council International
Weinberg, Bergeson and Neuman
1300 Eye Street, NW, Suite 1000 West
Washington, D.C. 20005
IV-D-12 Mr. John F. Welch
President
Safe Buildings Alliance
Suite 1200, Metropolitan Square
655 Fifteenth Street, NW
Washington, D.C. 20005
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TA3LE 2-1. LIST OF WRITTEN COMMENTERS ON THE PROPOSED
SCHEDULE FOR THE PROMULGATION OF EMISSION
STANDARDS (CONCLUDED)
Docket item number3 Commenter and affiliation
IV-D-13 Mr. B. J. Pigg
President
Asbestos Information Association
1745 Jefferson Davis Highway
Crystal Square 4, Suite 509
Arlington.. Virginia 22202
IV-D-14 Mr. Paul C. Bailey, Jr.
Director of Environmental Health
Affairs Department
American Petroleum Institute
1220 L Street, NW
Washington, D.C. 20005
IV-D-15 Mr. Charles D. Malloch
Director, Regulatory Management
Monsanto Company
800 N. Lindbergh Boulevard
St. Louis, Missouri 63167
IV-D-16 Mr. Gary E. Mosher
Director of Environmental Affairs
American Foundrymen's Society, Inc.
505 State Street
Des Plaines, Illinois 60016-8399
IV-D-17 Mr. Michael J. Bradley
Executive Director
Northeast States for Coordinated
Air Use Management
129 Portland Street
Boston, Massachusetts 02114
IV-D-18 Mr. James E. Gilchrist
Vice President for Environmental
Affairs
American Mining Congress
1920 N Street, NW, Suite 300
Washington, D.C. 20036-1662.
aThe docket number for this project is A-91-14. Dockets are
on file at the EPA's Air Docket in Washington, D.C.
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the source category schedule for standards, or the source
category list Federal Register notice (57 FR 31576;
July 16, 1992). The commenters asserted that the EPA should
publish a description of each source category and its
associated HAP's along with the schedule. One of the
commenters (IV-D-8) suggested that the EPA develop a decision
tree for determining regulatory applicability, similar to the
one being developed for the synthetic organic chemical
manufacturing industry (SOCMI) source category. Another one
of the commenters (IV-D-15) recommended a hotline be
established so facilities can obtain assistance in determining
within which category a process falls. The commenter
(IV-D-15) noted that some form of written communication would
be needed and that the determination would need to be binding.
Several commenters (IV-D-1, IV-D-5, IV-D-15) suggested
that a list of major products from each source category be
included in the schedule notice. One of the commenters
(IV-D-5) suggested that a list of relevant Standard Industrial
Classification (SIC) codes also be included. The commenter
(IV-D-5) asserted that such additional information would
assist operators in identifying the source categories to which
they belong, and in planning and allocating resources for
compliance.
Four commenters (IV-D-1, IV-D-5, IV-D-8, IV-D-15)
suggested the EPA include table 3.1 of the December 14, 1990
document "Draft Documentation for Developing the Source
Category List" in the schedula notice because this table
provides the corresponding speciation profiles used to
associate HAP's with source categories and thus helps clarify
the sources and HAP *s intended to be regulated under each
source category.
Two commenters (IV-D-5, IV-D-15) stated that it was
essential that a mechanism be developed for determining under
which source category a production unit is included on the
list of source categories in section 112(c) of the Clean Air
Act, in order to make decisions concerning the equivalent
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emission limitation by permit under section 112(j), and in
order to file enforceable commitments under the section
112(i)(5) early reduction program.
Response; Much of the information the commenters
requested is provided in the EPA report for the initial list,
"Documentation for Developing the Initial Source Category List
- Final Report" (EPA-450/3-91-030; July 1992. Docket
No. A-90-49, Item No. IV-A-55). Appendix A of this source
category list report contains descriptions of each listed
category of major sources. The information provided includes
the types of operations, processes, and equipment included
within each category of sources.
Table 3.1 of the source category list report contains a
listing of each category of major sources and the HAP's
currently associated with each category by industry group. A
listing of categories of area sources and associated HAP's can
be found in table 4.1. Tables 3.1 and 4.1 together serve as a
revised version of table 3.1 of the 1990 draft source category
list document. These tables are too lengthy to incorporate
into a Federal Register notice, but may be accessed by viewing
the source category list report contained in the docket under
Docket No. A-90-49, Item No. IV-A-55, or by contacting the
National Technology Information Service (NTIS) at 5285 Port
Royal Road, Springfield, Virginia 22161, Phone Number
(703) 487-4650, Order Number PB92-218429. Because of current
data limitations, a more comprehensive discussion of processes
and equipment, and all associated HAP's for each source
category is not presently available. However, during the
course of regulatory development, each source category will be
further examined to determine specifics about its processes,
equipment, products, HAP emissions, and applicability. During
this process, relevant SIC codes might be identified on a
source cc ory specific basis where good correlations can be
detarmint This information will be available from the EPA
standard development project teains, who will be communicating
with interested trade and industry groups, and other
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interested parties, starting early in the development process
of emission standards. As stated in the initial source
category list Federal Register notice:
The Agency recognizes that these descriptions (of what
each listed source category comprises), like the list
itself, may be revised from time to time as better
information becomes available. The Agency intends to
revise these descriptions as part of the process of
establishing standards for each category. Ultimately, a
definition of each listed category, or subsequently
listed subcategories, will be incorporated in each rule
establishing a NESHAP for a category. (57 FR 31576/
July 16, 1992).
Therefore, the EPA cannot make such preliminary descriptions
binding. The EPA encourages interested parties to communicate
with the appropriate EPA standard development teams early in
the regulatory process.
In response to the comments relating to section 112(j),
the EPA intends to make information available regarding source
category definitions, applicability, and controls before the
section 112(j) provisions would take effect for a source
category. The EPA encourages interested parties to
communicate with the appropriate EPA project teams well in
advance of the time that section 112(j) provisions might apply
for a source category. Readers are referred to the proposed
Equivalent Emission Limitations by Permit Rule, which was
published in the Federal Register on July 13, 1993
(58 FR 37778).
The comments relevant to section 112(i)(5) of the 1990
Amendments have been submitted to the EPA project team
implementing this program. The early reductions project team
is aware of the commenter's concerns about applicability.
Again, the EPA encourages the interested parties to
communicate with the appropriate project teams to discuss
these concerns.
Regarding the commenter's suggestion to develop decision
trees to assist with determining regulatory applicability, the
EPA believes that the commenter is referring to the
applicability decision figures included in section VI.A of the
proposed emission standard for the SOCMI, the hazardous
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organic NESHAP (HON) (57 FR 62608; December 31, 1992).
similar decision trees, if developed, would be developed under
ndividual standard development activities after more
information about each source category is gathered.
The EPA does not plan to establish a hotline for source
category determinations. However, the EPA encourages indu£»try
to provide any available data that may be useful in the
development of emission standards. Project status updates on
standards and other rule makings are typically presented
through such forums as the National Air Pollution Control
Techniques Advisory Committee (NAPCTAC) and the National Air
Toxics Inventory Clearinghouse (NATICH) newsletter. In
addition, a Regulatory Agenda is published in the Federal
Register approximately twice per year which provides
descriptions of various regulatory projects and the EPA
personnel to contact for more information. The EPA will
provide interested parties additional information upon
request, on a source category specific basis, as it becomes
available.
2.2 SECTION 112(g)
Comment; One commenter (IV-D-2) was concerned about rhe
impact of case-by-case maximum achievable control technology
(MACT) determinations, under section 112(g) of the 1990
Amendments, as a facility undergoes changes or expansions
(i.e., modifications). The commenter (IV-D-2) was concerned
that a broad and complex section 112(g) approach may subject
routine activities to section 112(g) review. The commenter
(IV-D-2) also questioned the interplay between section 112(g)
and the Title V operating permit program. The commenter
(IV-D-2) expressed concern that case-by-case MACT requirements
under section 112(g) would slow down the progress of research
and development and manufacturing advancement, and reduce
technical flexibility a"nd innovation. The commenter (IV-D-2)
as also concerned about the potential for inconsistency among
ase-by-case MACT determinations by State permitting
authorities, and requested early interaction with the EPA in
order to develop acceptable MACT requirements.
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Response; These comments pertain to the development of
the 112(g) program. The EPA has submitted these comments to
the EPA project team developing the section 112(g) program.
The EPA is aware of these concerns regarding section 112(g),
and is striving to minimize negative impacts while meeting the
statutory requirements of the 1990 Amendments.
2.3 SOURCE CATEGORY LIST
Several commenters discussed issues related to
determinations made during the development of the initial
source category list, which was published in the Federal
Register on July 16, 1992 (57 FR 31576). These comments are
summarized and responded to in this section by individual
source category, although the decisions to list source
categories, and potential revisions to the source category
list, are not being addressed under the source category
schedule for standards action. During the course of
regulatory development, the EPA will study individual source
categories in greater detail. Listing determinations and
potential source category list revisions will be explored
during this process.
2.3.1 SOCMI Source Category^
Comment: One commenter (IV-D-3) argued that SOCMI should
not be regulated as one category, but should be divided into
subcategories. The commenter (IV-D-3) stated that the NESHAP
for SOCMI, if developed for one category, would under-regulate
some plants while over-regulating others. The commenter
(IV-D-3) stated that the EPA should "divide the SOCMI into
appropriate subcategories so that the regulations could be
carefully tailored to the sources." Moreover, the commenter
(IV-D-3) stated that the only reason provided for regulating
SOCMI as one source category is to meet the schedule that was
established by Congress. Additionally, the commenter (IV-D-3)
noted that the proposed regulatory schedule applies to both
continuous and batch SOCMI processes. The commenter (IV-D-3)
indicated that the EPA is currently involved in drafting
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regulations that address differences between continuous and
batch processes, and for that reason, these different process
types should not be required to meet the same schedule.
Response; The EPA has the authority to subdivide
currently listed source categories as new information becomes
available during the regulatory development process. As
previously stated, the HON is the NESHAP that was proposed for
the SOCMI source category on December 31, 1992 (57 FR 62603).
These comments, although responded to as part of this action.
have also been forwarded to the EPA's HON project team for
consideration. The SOCMI source category was previously
listed as more than 400 separate source categories on the
draft source category list (56 FR 28548; June 21, 1991).
These separate source categories.were subsequently aggregated
into one category for the initial source category list
(57 FR 31576; July 16, 1992) based on considerations and
discussions among the EPA and the regulated community.
Aggregating the separate SOCMI categories into one category
allows emissions averaging among various process lines and
units at any one SOCMI source. A more thorough discussion of
emissions averaging may be found in the proposed HON
(57 FR 62608; December 31, 1992). The scheduling requirements
established by Congress were not the reason SOCMI is
considered one source category.
The proposed HON covers both batch and continuous
processes for four of the five emission points (i.e., transfer
operations, storage tanks, wastewater operations; and
equipment leaks). The EPA agrees that different regulatory
approaches are appropriate for vents from batch processes
versus vents from continuous processes. However, for storage
tanks, transfer operations, wastewater operations, and
equipment leaks, there are no technical reasons to treat
continuous and batch processes differently regarding
appropriate control technologies. Regardless of whether the
process is batch or continuous, the control technology is
typically the same for these four emission points.
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On the other hand, some control devices may not be
appropriate for control of batch process vents, which have
only episodic emissions. Instead, other control technologies
not considered in the HON may be better suited for batch
process vents. For this reason, the EPA decided not to
include batch process vents in the proposed HON. However,
this does not prohibit additional emission standards for batch
process vents for SOCMI, or any other source category, from
being developed in the future. Readers are referred to the
HON proposal (57 FR 62608; December 31, 1992) for more
information.
2.3.2 Lead Acid Battery Manufacturing Source Category
Comment: One commenter (IV-D-11) maintained that
inadequate and outdated emissions data taken from a November
1979 study "Lead Acid Battery Manufacture—Background
Information for Proposed Standards," Draft Environmental
Impact Statement (EIS), (EPA 450-/3-79-028a; November 1979)
were used as the basis in the EPA's determination to list lead
. acid battery manufacturing as a category of major sources.
The commenter (IV-D-11) noted that the EPA's source category
list background document (i.e., "Documentation for Developing
the Initial Source Category List - Final Report") reveals that
the EPA decided to remove categories from the draft source
category list modeled as area sources in September 1991,
including lead acid battery manufacturing, unless they were
identified as likely containing a major source. The commenter
(IV-D-11) stated that the lead acid battery manufacturing
source category does not contain a major source, and therefore
should be removed from the source category list.
Response; The EPA maintains that during the process of
developing the source category list, under section 112(c),
available information indicated that the lead acid battery
manufacturing source category contained a major source. The
reader is referred to the "Documentation for Developing the
Initial Source Category List - Final Report" (Docket
No. A-90-49, Item No. IV-A-55). Therefore, the lead acid
battery manufacturing source category was included on the
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initial source category list (57 FR 31576; July 16, 1992).
The decisions to list source categories, and potential
revisions to the source category list, are not being addressed
under today's schedule action. As stated in the draft schedule
for standards Federal Register publication on September 24,
1992 (57 FR 44147), under section 112(e), comments were
solicited regarding scheduling of source categories. The
draft source category list, under section 112(c), providing
opportunity for public comment on the listing determinations,
was published in the Federal Register on June 21, 1991
(56 FR 28548). During the course of regulatory development,
the EPA will study individual source categories in greater
detail. Listing determinations and potential source category
list revisions will be explored during this process. The
source category list will likely be revised sometime in the
future under a separate action. Since the lead acid« battery
manufacturing category is scheduled in the 10-year group and
is not currently an active project, these comments have been
submitted to the EPA's Industrial Studies Branch, which will
likely be involved in developing the regulation for this
source category.
2.3.3 Asbestos Processing Source Category
Comment; One commenter (IV-D-13) asserted that the
asbestos processing source category should be removed entirely
from the source category list and schedule, citing low
emissions, declining consumption and production, and high
costs as reasons why additional control of the industry is not
needed. The commenter (IV-D-13) objected to the EPA's listing
of asbestos processing as a category of area sources.
Further, the commenter (IV-D-13) stated that asbestos
processing could not afford or achieve any additional
requirements that the EPA could impose, and that a rulemaking
effort would be a waste of EPA resources.
Another commenter (IV-D-12) asserted that the goals of
section 112 of the 1990 Amendments are met for asbestos
processing or augmented by existing or proposed rules under
various other statutes. The commenter (IV-D-12) asserted that
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the 1990 Amendments goal of public health protection has been
achieved through the various asbestos regulations already in
place, and that the January 10, 1989 proposed rule revisions
for the asbestos NESHAP (54 FR 912) stated that the Asbestos
NESHAP is effective in reducing emissions and protecting the
public health. The commenter (IV-D-12) also referred to the
EPA's NAPCTAC meeting notes for the January 1991 meeting,
stating that possible NESHAP revisions may result in small
emissions reductions and high costs. The commenter (IV-D-12)
discussed other EPA asbestos regulations and guidance and the
areas that they regulate.
Response; Asbestos processing is currently the only
asbestos-related source category on the initial source
category list, and it is included only as a category of area
sources. The asbestos processing was listed as a category of
area sources after the EPA found that the category presented a
threat of adverse effects to human health. The health effects
associated with exposure to asbestos are well documented.
Numerous occupational exposure studies, supported by animal
studies, clearly indicate that asbestos is a human carcinogen.
A more thorough discussion of the emissions and risk
associated with asbestos processing, and the listing decision,
is explained in section IV of the Federal Register publication
entitled "Initial List of Categories of Sources Under
Section 112(c)(l) of the Clean Air Act Amendments of 1990"
(57 FR 31576; July 16, 1992). The comments have been
forwarded to the EPA project team developing emissions
standards for the asbestos processing source category so that
the project team is aware of the industry's concerns. The
asbestos processing source category will be studied more
thoroughly during regulatory development. Readers are
referred to section 2.3 of this document for further
discussion of source category list determinations. Interested
parties are encouraged to contact the project team directly to
discuss these concerns. For more information, contact the EPA
at the addresses in the schedule for standards Federal
Register notice.
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2.3.4 Stationary Internal Combustion Engines and Stationary
Turbines
Comment; One commenter (IV-D-7) asserted that the
stationary internal combustion engines and stationary turbines
categories incorrectly included natural gas-fired engines and
turbines in the same promulgation schedule with other engines
and turbines. The commenter (IV-D-7) argued that if natural
gas-fired engines and turbines were separated in the source
category ranking system (SCRS), their rankings would have been
considerably reduced, because: (1) natural gas is 90 percent
methane; (2) ground level concentration estimates are low; and
(3) in the gas transmission industry, these engines and
turbines are primarily positioned in remote locations away
from populated areas, thus reducing potential exposure. The
commenter (IV-D-7) suggested establishing a category for
natural gas-fired engines and turbines in the 10-year
timeframe, in order to allow time to determine if there are
any HAP emissions of concern from these engines and turbines.
Alternatively, the commenter (IV-D-7) suggested separating
natural gas-fired engines and turbines from the larger
category and establishing special provisions for them within
the broader standard.
Response: The stationary internal combustion engines and
stationary turbines source categories are scheduled in the
10-year timeframe and are not currently active projects.
Therefore, the comments addressing these source categories
have been submitted to the EPA's Industrial Studies Branch,,
who will most likely be involved in developing the
regulations.
Subcategorizing listed source categories is not part of
the action being taken under the schedule for standards
Federal Register notice. During the course of regulatory
development, the EPA will study individual source categories
in greater detail. Listing determinations and potential
source category list revisions will be explored during this
process.
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2.4 SOURCE CATEGORY RANKING SYSTEM METHODOLOGY OR APPROACH
2.4.1 General
Comment: Five conunenters (IV-D-l, IV-D-4, IV-D-5,
IV-D-15, IV-D-17) approved the EPA's use of the SCRS in
prioritizing source categories. One commenter (IV-D-17)
considered the SCRS approach to be consistent with section
112(e) criteria for determining the schedule. Two conunenters
(IV-D-4, IV-D-17) were pleased that SCRS scores are derived by
combining health effects scores with exposure scores for each
pollutant. However, many commenters also stressed that the
SCRS has limited or no applicability elsewhere. Some of these
commenters (IV-D-l, IV-D-5, IV-D-15) agreed with the EPA's
position that a higher SCRS score does not necessarily mean a
greater risk than a lower SCRS score. One commenter (IV-D-18)
wanted the EPA to confirm in the Federal Register notice
supporting the schedule that: (l) the SCRS was used only for
this preliminary screening and is not to be used for either
risk assessment or any other regulatory purpose; (2) more
accurate and realistic information shall be used in developing
the section 112 regulations for the scheduled categories; and
(3) the commenter may submit additional information in the
future that may be relevant to schedule adjustments.
One commenter (IV-D-5) asserted that the SCRS process
must be validated to assure that the ranking it produces has
some basis to justify using it for developing the schedule.
The commenter (IV-D-5) suggested doing an in-depth study on a
few of the categories to confirm the results from the SCRS
process, noting that this could demonstrate whether or not the
results are consistent with results that would be expected
from a more complete review.
Response: The SCRS addresses two of the section
112(e)(2) criteria (i.e., adverse effects of the HAP's on
public health; and the quantity and location of emissions of
HAP's) by generating a relative ranking score for each source
category based on emission estimates, toxicity data, and to a
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lesser degree, the location of emitting facilities. However,
the SCRS does not estimate absolute or relative risk,
population exposure, or impacts.
Several factors were considered when developing the
schedule for standards including: the SCRS ranking scores;
the EPA's capability to meet the numerical and temporal
requirements of section 112(e); and the efficiency of grouping
categories in the same timeframe. Admittedly, the SCRS
methodology and data input have limitations. However, for its
limited use, the SCRS and its present results are adequate for
assisting with the development of the schedule for standards.
It was the only tool reasonably available that could address
the criteria of section 112(e)(2) for a large number of source
categories in the short time available. The EPA does not plan
to revise and rerun the SCRS with new data. Currently, the
EPA does not intend to use the SCRS for any other regulatory
purpose. The EPA realizes the restricted use of the SCRS and
encourages the public and government agencies not to use
incorrectly, or misinterpret, the results.
The SCRS methodology includes several assumptions and
utilizes simplified algorithms. In order to evaluate
thoroughly the SCRS ranking, more facility-specific data would
be needed, along with other data such as EPA-verified health
effects benchmarks. Currently, this information is not
available for many of the categories or pollutants. The EPA
considers the current SCRS results to be adequate for
assisting with the development of the schedule for standards.
2.4.2 Exposure Score
Comment: One commenter (IV-D-17) was concerned with the
use of average county population density in a
50-kilometer (km) radius of the facility for the long-term
aggregate exposure score because the resulting score may
underestimate the risk to. individuals that live closer to the
facility and, therefore, would likely be exposed to higher HAP
concentrations. Another commenter (IV-D-14) also objected to
the use of an average county population density because this
method gives unwarranted priority to facilities located in
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unpopulated parts of a heavily populated county. The second
commenter (IV-D-14) suggested that the EPA incorporate the
census-based population exposure capabilities of the Human
Exposure Model (HEM) into the SCRS. One commenter (IV-D-17)
was concerned that several assumptions made in the SCRS might
underestimate the impact of emissions from source categories,
such as the use of: (1) nationwide estimates; (2) uniform
population exposure; and (3) constant average dispersion
parameters for all pollutants and sources.
Response: For detailed information on the SCRS
methodology, see the draft schedule Federal Register notice
(57 FR 44147; September 24, 1992) and the SCRS methodology
document entitled "Schedule for Standards: Methodology for
the Source Category Ranking System" (Docket No. A-91-14, Item
No. IV-A-1). In summary, the SCRS calculated four separate
exposure scores: the long-term aggregate, the long-term
maximum, short-term aggregate, and the short-term maximum
exposure scores. Emissions estimates were the most sensitive
factors in the calculation of each of the four source category
exposure scores. Population information, although limited,
was factored into one of the four exposure scores, the long-
term aggregate. Since the SCRS contains many assumptions, and
uses generic algorithms and readily available data of varying
quality, the exposure scores are not to be considered exposure
estimates.
In response to the comment on use of a 50-km radius, the
long-term aggregate exposure score theoretically represents a
population-based exposure score and is not intended to
represent the maximally exposed individual. A 50-km radius
was incorporated into the long term aggregate exposure score
algorithm because it is the maximum downwind distance to which
meteorological dispersion conditions are considered to be
reliable using the EPA's dispersion models. A second long-
term score, the long-term maximum exposure score, is used to
represent a theoretical maximally exposed individual. In this
algorithm, it is assumed that the highest concentration is
typically 200 meters (m) downwind. However, since these
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values are constants incorporated into generic algorithms by
which all source categories are scored, and since the SCRS
does not estimate exposure or risk, it is arbitrary what radii
and distances are used in the SCRS exposure scores. The
exposure scores are normalized (given a value between 0 and
l), and then multiplied by a normalized health effects score
that results in unitless overall source category scores which
are used to produce a relative ranking. If other constant
values for radii or distance were to be used (e.g., 20 km and
100 m, respectively) in the generic algorithms, the SCRS
relative ranking results would change very little, if at all.
Exposure modeling using detailed census data (e.g., such
as the HEM model) was not used in the SCRS because the EPA" did
not have adequate facility-specific data for many of the
source categories. Also, performing exposure modeling for all
facilities in each of the listed source categories could
require an enormous level of effort and is beyond the scope of
work necessary to support the schedule for standards. Average
population density, and other assumptions such as constant
dispersion parameters for all pollutants, are appropriate for
the SCRS given its limited use and data availability.
2.4.3 Health Effects Score
Comment: One commenter (IV-D-17) recommended that the
EPA use acute health effects endpoints rather than the lethal
dose to 50 percent of the exposed population (LDso) currently
used in the SCRS. The commenter (IV-D-17) was also concerned
about the combination of health effects data on acute
lethality, reproduction effects, and other noncancer effects
that may underestimate public health impacts.
In addition, the commenter (IV-D-17) argued that the
nationwide emissions estimates and national population density
do not accurately show the public health impact from exposure
to area source emissions. The commenter (IV-D-17) recommended
incorporating uncertainty factors and environmental effects in
the SCRS.
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One commenter (IV-D-4) expressed concern over the use of
data from the Registry of Toxic Effects of Chemical Substances
(RTECS), since it is not a peer-reviewed journal, and
recommended using well-supported toxicity data for individual
chemicals, if available, to develop the health effects score.
Another commenter (IV-D-5) mentioned that the data used
in the SCRS are very limited and frequently out-of-date. As
an example, the commenter (IV-D-5) noted that the RTECS data
base is 6 years old. The commenter (IV-D-5) cautioned that
the SCRS mathematical scoring, on several levels, crosses such
a diverse stratum of health effects and agents that any
scientific relevance is distorted. The commenter (IV-D-5)
protested that the SCRS approach does not address whether the
health effects only occur when a threshold limit is exceeded
for a certain HAP.
Another commenter (IV-D-15) noted that the SCRS is too
ill-defined for the assignment of potential health effects for
a particular source category, and, therefore, contended that
the term "source category risk score" is not correctly used.
The commenter also claimed that the health effects score,
particularly the use of RTECS data, should be scientifically
based. The commenter (IV-D-15) stated that RTECS contains a
number of inaccurate values, missing data, and
misinterpretations on severity. Also, the commenter (IV-D-15)
stated that the EPA used surface area corrections for route-
to-route differences when the current EPA method is body
weight to the 3/4 power.
Response: The health effects score for each pollutant
was based on four health effects endpoints (i.e., cancer,
reproductive/developmental effects, acute lethality, and
"other toxicity"). The "other toxicity" endpoint was based on
acute or chronic health effects data other than cancer
(i.e., noncancer effects)., that were not included in the
reproductive/developmental or acute lethality endpoints. The
LDso and lethal concentration to 50 percent of exposed
population (LCso) were used to calculate the score for acute
lethality. These values were a useful measure of relative
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toxicity since the data vere readily available and the
endpoint (i.e., 50 percent death) is consistent across
pollutants. Other acute benchmarks, such as levels of concern
(LOC's) and doses immediately dangerous to life and health
(IDLH's) are based on LDso and LCsg data, and therefore, would
have yielded similar relative results. The LD$Q and LCso data
were useful for scoring the pollutants in one of the four
health effects endpoints. The lowest oral dose reported to
cause a health effect (TDLQ), or lowest concentration when the
su ance is in air (TC^o), from the RTECS database were used
to derive the reproductive/developmental health effects score,
and the "other toxicity" score for most pollutants in the
SCRS.
The primary source of information for noncancer health
effects was RTECS, which is a data base developed and
maintained by the National Institute of Occupational Safety
and Health. The RTECS data base is widely used by both
industry and regulatory agencies as a source of toxicity data.
The RTECS represents one of the most readily available and
comprehensive sources of information on noncancer
toxicological endpoints. When the health effects data were
being compiled for the SCRS, the most current RTECS data were
used (see Docket No. A-91-14, Item No. II-A-1). It wc-ild have
been desirable to obtain peer-reviewed, noncancer hea. n data,
and verified health effects benchmarks such as the EPA's
inhalation reference concentrations (RfC's). However, RfC's
are not available for a significant number of the HAP's, and
therefore, RfC's were not used in the SCRS. Since LDso's,
LCso's, TDLo'sf and TCLO'S were available for most of the
HAP's, these values were used in the SCRS. Although the RTECS
data base itself is not formally peer reviewed, the data are
from the scientific literature. The EPA recognizes the
limitations associated with the lack of peer review; however,
for compiling health effects information for the 189 HAP's for
incorporating into a screening tool such as the SCRS, RTECS
was a valuable source.
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Threshold limits were not considered in the SCRS. For
many pollutants, data are inadequate to determine threshold
limits, if they exist. More importantly, since the SCRS does
not estimate exposure or risk, it cannot determine if a
threshold effect level might be exceeded. The pollutants were
scored based on relative potency. The SCRS generates a
relative ranking based on emissions and toxicity data, but
does not attempt to determine if public health impacts
actually exist. Therefore, threshold levels were not
considered.
The'terminology "source category risk score" was used in
some earlier docket items. After further review, the EPA
recognized that this terminology could be misleading since the
SCRS does not estimate risk. Therefore, in the draft schedule
Federal Register notice (57 FR 44147; September 24, 1992), and
in the more recent docket items, including the "Schedule for
Standards: Methodology for the Source Category Ranking
System" (Docket No. A-91-14, Item No. IV-A-1), this
terminology has been changed to "source category score." The
draft schedule notice, the source category schedule for
standards Federal Register notice, and the methodology
document, clearly indicate that the SCRS does not estimate
risk. The EPA encourages the public not to misinterpret, or
use incorrectly, the SCRS results.
As mentioned above, the health effects score was derived
from four endpoints. This approach was used so that the SCRS
would cover a wide range of health concerns. There are other
possible methods for combining various toxicity and emissions
data to rank source categories. However, given the
limitations on time and data availability, the EPA considers
the methodology used in the SCRS to be adequate for its
limited purpose.
In response to the comment regarding route-to-route dose
conversions, in the SCRS, dose data were all converted to
common units of mg/kg/day, so that health effects data from
the various routes of exposure could be compared. The method
used is explained in the "Schedule for standards: Methodology
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for the Source Category Ranking System." Since the SCRS
produces a relative ranking based on readily available data,
and because of the limited application of results, the EPA
considers the method described in the methodology document to
be adequate for the SCRS given it's limited use.
In response to the commenter who suggested that the EPA
incorporate uncertainties in the SCRS, the EPA recognizes that
uncertainty factors are a very important concern when
conducting risk assessments, and that defensible risk
assessments should contain some degree of uncertainty
analyses. For estimating risk or impacts, it is important to
consider both quantitave and qualitative uncertainty.
However, uncertainty analyses would have limited utility for
producing a relative ranking. Since the SCRS generates a
relative ranking, and does not estimate risk or impacts, and
since the SCRS was only a tool used in conjunction with the
efficiency of grouping and other considerations in developing
the regulatory schedule, uncertainty factors were not
incorporated into the SCRS.
2.4.4 Environmental Effects
Commenti Two commenters (IV-D-14, IV-D-17) suggested
that potential adverse effects to the environment also be
considered in developing the schedule. Specifically, one of
these commenters (IV-D-14) recommended that aquatic toxicity,
bioaccumulation, effects on terrestrial wildlife, and the
effects of metals on plants be considered. This commenter
(IV-D-14) did, however, recognize that the availability of
toxicity data for effects on humans and the environment are
limited.
Response; Section 112(e) of the 1990 Amendments states,
"In determining priorities for promulgating standards . . .
the Administrator shall consider . . . adverse effects to
public health and the environment." In response to these
comments on environmental effects, and after further EPA
review, the EPA has conducted a limited technical analysis to
address ecological concerns. The analysis consists of two
relative rankings of the source categories. One ranking is
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based on emissions estimates, aquatic toxicity, and
bioconcentration. The other ranking is based on the same
three parameters plus environmental partitioning, which is the
tendency of a chemical to be distributed among media
(i.e., air, water, soils and sediments, biota). The
ecological data (i.e., aquatic toxicity, bioconcentration, and
environmental partitioning) were primarily obtained from the
draft "Focus Chemicals for the Clean Air Act Amendments Great
Waters Study" report (Attachment A of Docket No. A-91-14, Item
No. IV-A-2). The emissions estimates were gathered from the
SCRS data base (Docket No. A-91-14, Item No. II-B-5). The
resulting relative rankings are called the Aquatic
Toxicity/Bioconcentration (ATB) rankings in the remainder of
this document. Persistence of the HAP's was not directly
incorporated into the ATB relative rankings because of the
limited available data. Persistence -data (from the "Focus
Chemicals" report) were only available for about 50 percent of
the HAP's. Although the persistence data were not directly
incorporated into the ATB relative rankings, source categories
were identified if they emit HAP's which were considered
persistent in the "Focus Chemicals" report. Terrestrial and
wildlife effects were not considered because of the
limitations in readily available data, and the limited time
and resources available to the EPA for publishing the schedule
for standards by the deadlines imposed by the 1990 Amendments.
The ATB ranks are not ecological risk assessments, but rather
relative rankings based on some readily available
environmental data. A thorough discussion of the methodology,
issues, and results are contained in Docket No. A-91-14,
Category II-B.
After analyzing the ATB relative rankings along with the
separate effort to identify source categories that emit
persistent HAP's, and after re-addressing all the other
considerations that factored into the development of the
schedule, such as the SCRS, efficiency of grouping, EPA
resources, time needed to develop emission standards, and
ability to meet the numerical and temporal requirements of
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section 112(e), some changes have been made to the schedule
for standards. These changes are discussed in the schedule
for standards Federal Register notice (section IV, "Changes to
the Draft Schedule").
2.5 SCHEDULE AND RANKING FOR SPECIFIC SOURCE CATEGORIES
Comment: Two commenters (IV-D-2, IV-D-6) affirmed the
placement of their particular source categories on the
schedule. One of the commenters (IV-D-2), reported, however,
that the public docket for the draft schedule did not provide
information regarding the specific application of the source
category ranking criteria to individual source categories.
One commenter (IV-D-14) asserted that the oil and natural
gas production category should not be regulated in the 7-year
timeframe because a methodological flaw in the SCRS has
probably overstated the risk from this category. The
commenter (IV-D-14) argued that this category should have a
lower priority because it has low emission rates, and because
the remote location of most operations results in lower
exposure potential than predicted.
This commenter (IV-D-14) was also concerned about the
division of petroleum refinery operations into two separate
source categories on the initial list, and the different
timeframes to which they were assigned within the draft
schedule. The commenter (IV-D-14) was concerned that there
might be insufficient time to develop MACT standards for the
category "petroleum refineries - other sources not distinctly
listed" before the 1994 deadline. Additionally, the commenter
(IV-D-14) stated that this separation would preclude emissions
trading between these two source categories, even when
collocated.
One commenter (IV-D-7) suggested that the EPA establish a
separate subcategory for natural gas fired engines and
turbines, instead of including these processes in the more
broadly defined source categories called stationary turbines
and stationary internal combustion engines. The commenter
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(IV-D-7) suggested that this subcategory for natural gas fired
engines and turbines should be scheduled in the 10-year
instead of the 7-year timeframe.
Another commenter (IV-D-16) argued that the pollutant and
emissions information used to list and to develop the SCRS
score for the iron foundries and steel foundries source
categories was incorrect and ultimately skewed the SCRS rank
upon which the regulatory schedules for the iron foundries and
steel foundries source categories are based. The commenter
(IV-D-16) suggested that these source categories should be
scheduled in the 10-year timeframe.
Two commenters (IV-D-12, IV-D-13) asserted that, given
the current asbestos NESHAP's efficacy and the reduction in
asbestos use, the EPA should not schedule the asbestos
processing source category for rulemaking anytime in the near
future. Another commenter (IV-D-8) suggested that the
November 15, 1994 deadline may not be reasonable to the
following three source categories: methyl methacrylate-
butadiene-styrene terpolymers production, styrene-butadiene
rubber and latex production, and polystyrene production.
A fourth commenter (IV-D-10) reguested a 60-day extension
to the comment period, in order to further review SCRS ranking
information.
Response: As discussed under section 2.3 of this
document, the decisions to list a category and how to
subdivide or aggregate categories, such as petroleum refinery
operations, are not a part of this action. As discussed
previously, the source category list will likely be revised
sometime in the future under a separate action. The
scheduling decision for each source category was made after
reviewing all the considerations and criteria discussed in the
schedule for standards Federal Register notice. The SCRS is
considered an adequate tool for assisting in the development
of the schedule. The commenters did not submit new data on
emissions, health effects, or specific facility parameters.
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After further EPA review and evaluation of all the
considerations and criteria discussed in the draft schedule
for standards Federal Register notice, and after review of
public comments received on the draft schedule for standards
Federal Register notice, the EPA did make some changes to the
schedule. These changes, which are discussed in the schedule
for standards Federal Register notice, included moving the
iron and steel foundries source categories, and moving the
stationary turbines and internal combustion engines source
categories to the 10-year timeframe. However, the EPA does
not have sufficient information indicating that these other
specific suggested changes should be made. Therefore, none of
these other suggested changes have been made.
After further review, the EPA decided not to extend the
comment period as one commenter requested. The EPA realizes
that a 30-day comment period challenges the public to review
and respond quickly. However, the 1990 Amendments imposed an
extremely ambitious schedule, and to lengthen the comment
period may have resulted in additional delays beyond those
which this project has already encountered. The EPA has,
however, contacted the commenter directly to clarify some
confusion about the SCRS ranking, and to provide assistance in
locating the items in the docket related to that particular
source category.
2.6 FLEXIBILITY
Comment; Many commenters (IV-D-1, IV-D-3, IV-D-5,
IV-D-6, IV-D-9, IV-D-15, IV-D-17, IV-D-18) discussed the need
for some degree of flexibility within the schedule. The
commenters (IV-D-1, IV-D-5, IV-D-6, IV-D-9, IV-D-15, IV-D-17,
IV-D-18) said that the EPA should have the flexibility to
adjust the original schedule for regulating source categories
after the schedule for standards is published. The commenters
noted that the present rankings should be subject to change in
the event that new information becomes available and prompts
the EPA to recalculate a source category score which might
alter the relative rank. The commenters indicated that a
revised source category ranking should result in a change to
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the regulatory promulgation deadline. Furthermore, many of
these commenters asserted that as data quality and
availability improve, a new SCRS analysis changing the
relative ranking of source categories may prove that greater
risk reduction may be achieved in a shorter timeframe by
amending the schedule.
One commenter (IV-D-6) stated that flexibility was needed
if new source categories are added to the source category list
and schedule. A second commenter (IV-D-17) acknowledged that
the strength of the SCRS is its capacity to combine
information from multiple databases that can be updated as
needed. The commenter (IV-D-17) stressed the importance of
revising the methodology used to develop the SCRS as new
information becomes available. For example, the commenter
(IV-D-17) noted that both the Industrial Source Complex Short
Term and Long Term models (ISCST and ISCLT) have recently been
updated. The commenter (IV-D-17) recommended that the EPA
have the authority to change the schedule in the future, if
necessary, after periodic review and updates in methodology.
Another commenter (IV-D-3) stated that the EPA needs
flexibility in order to allow time for proper attention to the
technical details of writing the scheduled emission standards.
The commenter (IV-D-13) suggested the EPA work with Congress
to obtain flexibility in the regulatory timetable. Several
commenters (IV-D-1, IV-D-5, IV-D-15) asserted that the EPA
must be able to modify the schedule out of administrative
necessity in order to better meet the goals of the statute.
Two commenters (IV-D-6, IV-D-18) asserted that since
section 112(c) of the 1990 Amendments allows the EPA to amend
the list as appropriate, the EPA should also have the
flexibility to alter regulatory promulgation deadlines. One
of these commenters (IV-D-18) proposed that such revisions are
appropriate because section 112(b) instructs the EPA to add or
delete HAP's when specific conditions are satisfied, and that
the 1990 Amendments allow for the removal of source categories
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if the pollutants they emit have been delisted, or if the
projected risk from those pollutants drops below a certain
level.
Six commenters (IV-D-1, IV-D-5, IV-D-6, IV-D-9, IV-D-15,
IV-D-18) alleged that section 112(e) contains no prohibitions
against the EPA changing the schedule for standards. One of
the commenters (IV-D-18) interpreted the absence of such
prohibition to mean that the decision has been left to the
EPA's discretion This commenter (IV-D-18) argued that
Congress would have firmly indicated that the EPA would not
have the authority to adjust the regulatory schedule if
Congress had so intended. Finally, the commenter (IV-D-18)
asserted that if the EPA was deprived of its authority to
adjust the schedule, the revision authority described in
section 112(b) and 112(c) would lose much of its value. Three
commenters (IV-D-1, IV-D-5, IV-D-15) added that since
section 112(e) is not considered a rulemaking subject to
judicial review, the EPA should not be pressured regarding
revisions to the schedule by possible lawsuits or the
requirements of the Administrative Procedures Act,
5 U.S.C 7551 (1992). However, another commenter (IV-D-9)
maintained that the schedule should not oe altered unless a
significant change in the ranking of source categories occurs
based on the changing state of knowledge supporting the three
criteria used in establishing the schedule.
Response; The EPA interprets section 112 of the 1990
Amendments as permitting some flexibility concerning amendment
of the schedule. The comments received on the proposed
regulatory schedule regarding this issue support the
interpretation that the EPA has the authority to amend the
schedule and retain some regulatory flexibility after
publication of the schedule for standards. The EPA considers
it. impractical to have a strictly rigid schedule for the
reasons discussed in section I.B of the schedule for standards
Federal Register notice. To reiterate some of these reasons,
as new data becomes available, the EPA may identify changes to
the schedule that would facilitate a greater achievement of
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the prioritizing criteria of section 112(e). As pointed out
by some commenters, there may be situations where significant
new information is obtained (e.g., data indicating that a
source category presents much less of a hazard to public
health than previously thought, or the discovery that a source
category is posing a significant threat to the environment)
that warrants limited changes to the schedule. In addition,
amendment of the schedule may also be necessary if categories
on the initial source category list are delisted under the
authority of section 112(c)(9). Hence, the EPA anticipates
that it may, from time to time, amend the schedule for
standards.
The EPA does not anticipate frequent amendment of the
schedule for some important reasons. First, because of the
long lead time and significant resources required to
promulgate an emissions standard, the EPA will not have the
technical ability or resources to reschedule many standards,
particularly to move significant numbers of source categories
into earlier timeframes. Second, because of the
section 112(e) numerical and temporal requirements regarding
scheduling of standards (i.e\, regulate 40 source categories
by November 15, 1992; 25 percent of all listed source
categories by November 15, 1994; 50 percent by November 1997;
and 100 percent by November 2000), the EPA is limited in its
ability to defer categories into later timeframes without
moving a commensurate number of standards to earlier time
frames.
Therefore, the schedule will not be changing frequently,
but rather, may undergo some minor modifications as
significant new information becomes available. Of course, any
entirely newly listed categories will not affect the schedule,
as they have their own schedule under section 112(e)(5).
Source categories subsequently added to the 112(c) list shall
be scheduled for regulation by November 2000, or 2 years after
they are listed, whichever is later.
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2.7 EFFICIENCY C ' GROUPING
Comment; Four commenters (IV-D-1, IV-D-5, IV-D-8,
IV-D-15) cautioned the EPA to refrain from arbitrarily
grouping source categories for the sole purpose of making the
regulatory process easier and more convenient. Three of the
commenters (IV-D-1, IV-D-5, IV-D-15) were concerned that
arbitrary groupings could lead to implementation bottlenecks
and could complicate the residual risk determinations that
will be made under section 112(f). The commenters recommended
that, if the EPA determines a single standard applies to more
than one source category, the standard should be promulgated
separately for each source category.
The fourth commenter (IV-D-8) stressed that it is
incorrect to hasten the regulatory schedule for categories for
which information is more readily available just because they
are easier to regulate in a given timeframe, notwithstanding
the impact of their emissions on public health.
Another commenter (IV-D-6) suggested that the source
category list be reviewed for inconsistencies. Specifically,
the commenter (IV-D-6) referred to polyester resins
production, which has a scheduled promulgation date of
November 15, 1997 on the draft schedule, and polyethylene
terepthalate production, which had a scheduled promulgation
date of November 15, 1994. The commenter (IV-D-6) contended
that the two processes are essentially the same category arid,
therefore, should both be scheduled under the November 15,
1997, timeframe.
Another commenter (IV-D-15) reiterated previously
expressed concerns on the preliminary draft list of categories
(56 FR 28548; June 21, 1991) regarding the approach the EPA
used to identify which sources fell under which categories and
their respective schedules. The commenter (V-D-15) guestioned
why butyl benzy. phthalate, a phthalate plasticizer, is
included in the draft list of SOCMI processes (scheduled for
MACT promulgation by November 15, 1992) . This would result in
butyl benzyl phthalate production being regulated before the
phthalate plasticizers production source category listed under
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miscellaneous processes. The commenter (IV-D-15) questioned
the logic of requiring regulation of one phthalate plasticizer
8 years before the others. The commenter (IV-D-15) also
indicated that the EPA had not specified which category the
formaldehyde resins group would fall under, stating that it
could fit under either the acetal resins production, amino
resins production, or phenolic resins production categories.
Another commenter (IV-D-16) reiterated comments to the
preliminary draft list, and alleged that little reliable
quantitative data on emissions of HAP's from iron or steel
foundries were presented. The commenter (IV-D-16) stated that
due to different emissions, process, and technology
characteristics, iron foundries and steel foundries should not
be assigned the same regulatory schedule as other sources
grouped in the ferrous metal processing industry group. The
commenter (IV-D-16) requested a November 15, 2000 regulatory
schedule assignment.
Response; Section 112(e)(2)(C) of the 1990 Amendments
allows the EPA to prioritize regulations for source categories
based on "the efficiency of grouping categories or
subcategories according to the pollutants emitted, or the
processes or technologies used." This criterion enables the
EPA to utilize its technical resources for developing
regulations more effectively, and helps prevent the EPA from
duplicating regulatory efforts for two similar categories.
The EPA has considered in the past and will consider in the
future such characteristic as end products, processing steps,
raw materials, emitted pollutants, emission controls, economic
factors, and efficiency of using EPA resources in grouping
source categories into single regulatory projects. Of course,
without extensively studying each source category, it is often
difficult for the EPA to predict whether a particular emission
standard will closely resemble a standard for another source
category. The EPA understands that if it is later discovered
that initially grouped categories may not be effectively
regulated by one standard, the EPA will promulgate separate
standards for the source categories as necessary. However, to
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follow the commenter's suggestion of continuing to have
project groupings for similar categories, but then to
promulgate each emission standard at different times based on
the SCRS ranking would defeat the purpose of the efficiency of
grouping criteria and could have a substantial impact on the
EPA in meeting other goals of section 112.
The EPA investigated the commenter's allegation that the
polyester resins production is identical to polyethylene
terephthalate production. This review revealed that these
ategories are in fact distinct from one another, and should
amain as separate source categories. In particular,
polyethylene terephthalate is an ethylene glycol-based polymer
which is spun into fibers for clothing, blow-molded into
plastic bottles, or quenched and stretched to form specialty
films. Polyester resins, on the other hand, are styrene-based
resins that are used primarily in the manufacture of
fiberglass. Because of these differences, there is no
technical reason to schedule the two source categories in the
same timeframe. The polyester resins production source
category has been moved to the 10-year timeframe. The
polyethylene terephthalate production source category remains
scheduled in the 4-year timeframe. The reader is referred to
the Federal Register notice to the schedule for standards for
more discussion of the changes to the schedule.
In response to the comments regarding the formaldehyde
resins group, this is merely a title that has been adopted by
the EPA to refer to the NESHAP project intended to regulate
the acetal, amino, and phenolic resins production source
categories. By researching the individual categories, the EPA
discovered that each of these resin producers used
formaldehyde as a principal reactant in the polymerization
reaction. Consequently, the EPA decided to minimize its
regulatory resource efforts by grouping these three source
categories into one project. Although the same regulatory
project focuses on all three categories, th does not
necessarily suggest that the emission standards will be
equivalent. However, it means that information will be
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gathered simultaneously, that EPA work group membership will
presumably be similar (if not identical), and that the
emission standard(s) will most likely be proposed and
promulgated on the same schedules.
In response to a commenter's concerns regarding butyl
benzyl phthalate, the production of butyl benzyl phthalate is
included in the list of SOCMI processes which are proposed for
regulation under the HON (57 FR 62608; December 31, 1992). It
is included in the list of SOCMI processes because butyl
benzyl phthalate fits the definition delineated in the
proposed HON. The other phthalate plasticizers do not meet
the HON definition. Therefore, the other phthalate
plasticizers productions are grouped into a separate category
of major sources and were ranked separately in the SCRS. They
ranked relatively low in the SCRS and were scheduled in the
10-year timeframe. The list of SOCMI processes is not an item
for review under this action. However, the comment has been
forwarded to the EPA staff responsible for the proposed HON.
The iron foundries and steel foundries source categories
were scheduled independently of the other categories within
the ferrous metals processing industry group. However, after
further review by the EPA, the iron foundries and steel
foundries source categories have been moved to the 10-year
timeframe. In consideration of regulatory efficiency,
individual source categories within the ferrous metals
industry group may subsequently be grouped with one or more
other similar categories within or outside of the industry
group.
2.8 OTHER SCHEDULING CONSIDERATIONS
Comment; One commenter (IV-D-1) urged the EPA to avoid
setting schedule dates for source categories that are clearly
unattainable. The commenter (IV-D-1) mentioned the difficult
challenge imposed oh the EPA to meet the statutory deadlines,
and stated that it is important that section 112(d) standards
be of the highest quality possible. Therefore, the commenter
(IV-D-1) recommended and encouraged the EPA to focus on the
practical considerations of setting and meeting the source
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category schedule. The commenter (IV-D-l) stated that the EPA
should consider data availability and resource needs when
determining where to place certain source categories in the
schedule, recognizing that writing standards for certain
categories will be extremely resource-intensive compared to
other categories.
Response; The EPA agrees with the above recommendations.
The EPA considered data availability and resource needs, and
the ability to meet the scheduled deadlines, when developing
the schedule for standards. Some of the changes made to the
draft schedule for standards were partly based on these
considerations. The changes to the draft schedule are
discussed in the schedule for standards Federal Register
notice.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-453/K-93-U47
3. RECIPIENT'S ACCESSION NO
4. TITLE AND SUBTITLE
Source Category Schedule for Standards;
Public Comments and Responses
Summary of
5. REPORT DATE
September 1993
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
L). S. Environmental Protection Agency
Research Triangle Park, Nortn Carolina 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
08-01-0117
12. SPONSORING AGENCY NAME AND ADDRESS
Director, Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/200/Ut
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The EPA is publishing the source category schedule for emission standards as
required under section 112(e) of the Clean Air Act. The draft source category
schedule for standards appeureu in the Federal Register on September 2f, 1992
(57 FR 44147). The EPA received li> written comment letters from tne public. This
report summarizes all public comments and presents tne Agency's responses.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (ThisReport!
21 NO. OF PAGES
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2330-1 (R»v. 4-77} PREVIOUS EDITION is OBSOLETE
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