EPA-450/5-86-010
NATIONAL AIR TOXICS
INFORMATION CLEARINGHOUSE
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
ALAt?>۩
State and Territorial Air Pollution Program Administrators
Association of Local Air Pollution Control Officials
Methods for Pollutant
Selection and Prioritization
July 1986
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DCN No. 86-239-001-02-06
EPA Contract No. 68-02-4330
Work Assignment No. 2
EPA 450/5-86-010
NATIONAL AIR TOXICS INFORMATION CLEARINGHOUSE:
METHODS FOR POLLUTANT SELECTION AND PRIORITIZATION
Prepared for:
Beth Hassett
Project Officer
Strategies and Air Standards Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Prepared by:
Radian Corporation
3200 East Chapel Hill Road/Progress Center
Post Office Box 13000
Research Triangle Park, North Carolina 27709
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, INinois 60604
July 1986
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U,S. Environmental Protection Agency
n
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DISCLAIMER
This report has been reviewed by the Office of Air Quality Planning and
Standards, U. S. Environmental Protection Agency, and approved for
publication as received from Radian Corporation. Approval does not signify
that the contents reflect the views and policies of the U. S. Environmental
Protection Agency, nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
iii
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IV
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PREFACE
EPA has focused most of its past efforts in the control of air toxics
on the Clean Air Act Section 112 National Emission Standards for Hazardous
Air Pollutants (NESHAP) program. The Agency has undertaken measures that
will accelerate the standards setting process to reduce more rapidly the
risks resulting from exposure to air toxics. Yet there is still pressure
for information and action on the control of air toxics being brought to
bear by the public, who are concerned over continuing exposure to
potentially toxic air pollutants. This public pressure has had an impact
such that State and local agencies have developed or are now actively
developing air toxics regulatory programs to complement Federal activities.
In addition to accelerating Section 112 Federal Standards setting, EPA
is also supporting State and local air toxics control efforts. In response
to requests for assistance from State and local agencies, EPA has designed
and is implementing an information dissemination center, known as the
National Air Toxics Information Clearinghouse. The Clearinghouse is
composed of a computerized data base which contains indexed information on
toxic and potentially toxic air pollutants, several special reports such as
this one, hard copy reports of information from the data base, and a
quarterly newsletter. The Clearinghouse has been designed and is being
implemented in close coordination with the State and Territorial Air
Pollution Program Administrators (STAPPA) and the Association of Local Air
Pollution Control Officials (ALAPCO).
The purpose of this report is to describe various methodologies for
selecting and prioritizing substances of concern within an air toxics
program. The report is aimed at helping State and local agencies in
selecting substances for review and choosing an existing system or creating
a system to prioritize substances. Information on the pollutant selection
methodologies described was provided by several State and local agencies as
well as by EPA. The prioritization methodologies presented were developed
by State and local agencies, EPA, and other Federal agencies.
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Other Clearinghouse publications include:
• National Air Toxics Information Clearinghouse: Rationale for Air
Toxics Control in Seven State and Local Agencies, EPA 450/5-86-005,
NTIS: PB86 181179/AS, August 1985;
• National Air Toxics Information Clearinghouse: NATICH Data Base
Report on State and Local Agency Air Toxics Activities,
EPA 450/5-86-006, NTIS: PB86 200466/AS, September 1985;
0 National Air Toxics Information Clearinghouse: NATICH Data Base
Users Guide for Data Viewing, EPA 450/5-85-008,
NTIS: PB86 123601/AS, September 1985;
• National Air Toxics Information Clearinghouse: Ongoing Research
and Regulatory Development Projects, EPA 450/5-86-007, June 1986;
t National Air Toxics Information Clearinghouse: Bibliography of
Selected Reports and Federal Register Notices Related to Air
Toxics, EPA 450/5-86-008; July 1986;
• National Air Toxics Information Clearinghouse: How the
Clearinghouse Can Help to Answer Your Air Toxics Questions,
EPA 450/5-86-009; July 1986; and
• National Air Toxics Information Clearinghouse Newsletters,
December 1983, February 1984, April 1984, July 1984,
September 1984, December 1984, February 1985, May 1985,
August 1985, December 1985, March 1986, and June 1986.
VI
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ABSTRACT
The National Air Toxics Information Clearinghouse has been established
by the EPA Office of Air Quality Planning and Standards (OAQPS) in
coordination with the State and Territorial Air Pollution Program
Administrators (STAPPA) and the Association of Local Air Pollution Control
Officials (ALAPCO) for the purpose of aiding information transfer among
Federal, State, and local air quality management agencies. This report has
been published as part of that effort. The purpose of this report is to
describe various methodologies for selecting and prioritizing air pollutants
of concern within an air toxics program.
vii
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TABLE OF CONTENTS
Section Page
Li st of Tab! es xi
List of Figures xii
List of Abbreviations xiii
1.0 Introduction 1-1
1.1 Purpose 1-1
1.2 Methodology 1-1
1.3 Organization 1-1
1.4 Executive Summary 1-2
1.4.1 Pollutant Selection 1-2
1.4.2 Pollutant Prioritization 1-3
2.0 Pollutant Selection 2-1
2.1 Approaches to Pollutant Selection 2-1
2.2 Methods of Selecting Pollutants 2-2
2.2.1 Health Effects 2-3
2.2.2 Expected Occurrence 2-5
2.2.3 Other Lists 2-8
2.2.4 Internal Assistance From Divisions Within
the Agency 2-12
2.2.5 External Assistance 2-12
2.2.6 Commonly Selected Pollutants 2-13
2.3 Case Histories 2-13
2.3.1 Examples of Methods Used by State/Local
Agencies to Develop Lists of Pollutants 2-15
IX
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Section Page
2.3.2 Discussion of Methods Used by State/Local
Agencies to Select Pollutants 2-19
2.4 Data Sources Useful to Agencies Selecting
Pollutants , 2-21
3.0 Pollutant Prioritization 3-1
3.1 Prioritization Systems Based on Health Effects 3-2
3.2 Examples of Prioritization Based on Health Effects ... 3-4
3.2.1 Maine Bureau of Health 3-4
3.2.2 Massachusetts Department of Environmental
Quality Engineering 3-7
3.3 Multiple Factor Prioritization Systems 3-11
3.3.1 Modified Hazardous Air Pollutant
Prioritization System (MHAPPS) 3-11
3.3.2 Multimedia Environmental Goals 3-18
3.3.3 CERCLA Reportable Quantities 3-19
3.3.4 Oak Ridge National Laboratory Chemical
Scoring System 3-22
3.4 Comparison of MHAPPS, MEGs, RQs, and ORNL Systems 3-25
References R-1
Appendix: State of Indiana Air Toxics Questionnaire A-l
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LIST OF TABLES
Table Page
2-1 EPA's List of 37 Pollutants 2-9
2-2 Pollutants Addressed in EPA's Report on Air Toxics
in the United States 2-11
2-3 Fifty Most Frequently Selected Toxic Pollutants in
Seven Agencies 2-14
3-1 Ranking for Top Eleven Hazardous Air Pollutants/
Mixtures - Maine Department of Human Services 3-6
3-2 Massachusetts CHEM/AAL Summary for Eleven Sample Toxic
Chemicals 3-10
3-3 Groups, Factors and Subfactors Used in HAPPS
and MHAPPS 3-12
3-4 Sample MHAPPS Rankings 3-17
3-5 Primary Criteria for CERCLA Reportable Quantities
(RQs) 3-20
3-6 CERCLA Reportable Quantities for Eleven Example
Pollutants 3-23
3-7 Individual Scoring Systems of Each ORNL Chemical
Scoring System Component 3-24
3-8 Factors Addressed by Four Toxic Pollutant
Prioritization Systems 3-26
3-9 Procedural Features of Four Toxic Pollutant
Prioritization Systems 3-28
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LIST OF FIGURES
Figure Page
2-1 Examples of SIC/Pollutant Data Available in NATICH 2-6
2-2 Examples of Pollutant/SIC Data Available in NATICH 2-7
xii
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LIST OF ABBREVIATIONS
ACGIH - American Conference of Governmental Industrial Hygienists
ALAPCO - Association of Local Air Pollution Control Officials
CERCLA - Comprehensive Environmental Response, Compensation and Liability Act
LCgQ - Concentration required to kill 50 percent of exposed test species
LD50 - Dose required to kill 50 percent of exposed test species
IARC - International Agency for Research on Cancer
MEG - Multimedia Environmental Goal
MSDS - Materal Safety Data Sheet
MTL - Monitoring Trigger Level
NESHAP - National Emission Standard for Hazardous Air Pollutants
NATICH - National Air Toxics Information Clearinghouse
NIOSH - National Institute of Occupational Safety and Health
NTP - National Toxicology Program
OSHA - Occupational Safety and Health Administration
PEL - Permissible Exposure Limit (developed by OSHA)
RQ - Reportable Quantity
RTECS - Registry of Toxic Effects of Chemical Substances
STAPPA - State and Territorial Air Pollution Program Administrators
STEL - Short-Term Exposure Level (TLV-STEL) (recommended by ACGIH)
TC^Q - Lowest concentration reported to produce adverse health effects
TDLQ - Lowest dose reported to produce adverse health effects
TLV - Threshold Limit Value (recommended by ACGIH)
TSCA - Toxic Substances Control Act
TWA - Time Weighted Average (TLV-TWA)
WHO - World Health Organization
USPHS - U. S. Public Health Service
xiii
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1.0 INTRODUCTION
1.1 PURPOSE
The National Air Toxics Information Clearinghouse (the Clearinghouse)
has been established as a cooperative effort by EPA's Office of Air Quality
Planning and Standards, the State and Territorial Air Pollution Program
Administrators (STAPPA), and the Association of Local Air Pollution Control
Officials (ALAPCO) for the purpose of facilitating information transfer
among Federal, State, and local air quality management agencies. This
document has been published as part of that effort. The purpose of this
report is to describe various methodologies for selecting and prioritizing
pollutants of concern within an air toxics program. The report is aimed at
helping State and local agencies to select substances for review and to
choose an existing system or create a system for prioritization.
1.2 METHODOLOGY
The discussion of pollutant selection and part of the discussion on
pollutant prioritization were based on information gathered from agencies
that had responded to requests for information from the Clearinghouse. The
particular information used was from agencies who indicated that their
programs were based on specific lists of pollutants. Also, several agencies
were contacted and asked about their criteria for pollutant selection and if
they prioritized the pollutants selected in any way. In addition, various
EPA reports were referenced, particularly for information concerning the
more complex prioritization systems.
1.3 ORGANIZATION
This report is divided into three sections. Section 1.0 is the
introduction and executive summary, followed by Section 2.0 on pollutant
selection, and Section 3.0 on pollutant prioritization. Both Sections 2.0
and 3.0 begin with general descriptions of the topic followed by specific
examples.
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1.4 EXECUTIVE SUMMARY
This report is published as part of an ongoing effort by the
pollutants among Federal, State, and local air quality management agencies.
Methods of selecting and prioritizing toxic air pollutants are discussed and
examples (case histories) are presented illustrating how the methods have
been applied. This report is especially designed to provide assistance to
State and local agencies just beginning air toxics programs. However, it
can also be useful to those agencies already implementing control
requirements.
1.4.1 Pollutant Selection
Some agencies have found it useful to select, lists of toxic air
pollutants on which to focus regulatory and/or assessment efforts. Other
agencies have chosen not to restrict their efforts to specified lists, and
have instead chosen to regulate any toxic air pollutant under their air
toxic provisions.
Agencies that have selected specific pollutants of concern have chosen
them based on one or a combination of these five methods:
t Health effects evaluation,
• Expected occurrence,
• Other lists,
• Internal assistance from divisions within the agency, and
• External assistance.
When selecting pollutants by health effects, an agency may choose to list a
pollutant by virtue of the fact that it is a known or probable carcinogen,
because it has a reported LD50/LC5Q less than a previously determined value
which indicates the potential for acute toxicity, or because it has the
potential to cause other adverse health effects. ("LD50" and "LC50" are
defined in the list of abbreviations on page xiii.) When selecting
pollutants by expected occurrence, an agency may conduct surveys or
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screening studies as initial emissions inventories to determine which
chemicals are actually used/emitted within the State or region. Often,
agencies have used lists of pollutants selected by other States or lists of
pollutants developed by Federal agencies. For example, many States' lists
now contain EPA's "List of 37" or those pollutants given priority for NESHAP
study. Some agencies have incorporated EPA's list of 402 acutely toxic
chemicals.
Several agencies have requested assistance in selecting pollutants
internally, from other divisions within their agency such as water quality
divisions. Also, external assistance and review have been solicited from
toxicologists, physicians, consultants, academia, and industry.
1.4.2 Pollutant Prioritization
After a regulatory agency has selected pollutants of concern, the
agency often finds it useful to prioritize the pollutants. Reasons for
prioritizing pollutants include:
t Making a distinction for regulatory purposes among groups of
chemicals, such as carcinogens, noncarcinogens, and acutely toxic
chemicals;
• Identifying a subset of the larger list that will be addressed
initially for regulatory purposes;
t Identifying pollutants that warrant further study; and
t Maximizing the effectiveness of available resources.
Prioritization systems vary in complexity ranging from systems which
only distinguish between carcinogens and noncarcinogens to multiple factor
systems which rank or score chemicals in several categories. Four of the
more complex systems are described in this report. All four systems
consider other routes of exposure in addition to air. The first system
described is the modified hazardous air pollutant prioritization system
(MHAPPS), developed by the Pollutant Assessment Branch of EPA. MHAPPS is a
computerized ranking method which ranks pollutants based on eight factors
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such as health effects and exposure potential. MHAPPS includes options
which allow the user to change the relative emphasis or weight of the eight
factors. For example, the user may choose to emphasize acute exposure.
Another ranking system is Multimedia Environmental Goals (MEGs). This
system is based on a procedure developed by EPA's Industrial Environmental
Research Laboratory, now known as the Air and Energy Engineering Research
Laboratory. MEGs are levels of contaminants in the ambient air, water,
land, or effluents conveyed to these media, that are judged to be
appropriate for preventing negative ecosystem effects or that are
representative of the control limits achievable. MEGs include evaluation of
a chemical's adverse effects on human health, aquatic toxicity, and
phytotoxicity.
Reportable quantities (RQs), used in compliance actions with the
Comprehensive Environmental Response Compensation and Liability Act
(CERCLA), can be used as a ranking system. RQs are based on human and
mammalian toxicity, reactivity, and ignitability.
Finally, the Oak Ridge National Laboratory (ORNL) has developed a
Chemical Scoring System for EPA to score chemicals under the Toxic
Substances Control Act (TSCA). Thirty-four factors are evaluated for each
chemical in this system, including toxicity to terrestrial and aquatic
species, environmental fate, and exposure potential.
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2.0 POLLUTANT SELECTION
The methods used by various State and local agencies to select toxic
air pollutants are discussed in this section. Descriptions of the methods
are followed by case histories of the experiences of State and local
agencies in selecting toxic pollutants for review or regulation.
2.1 APPROACHES TO POLLUTANT SELECTION
Two distinct approaches have been taken by State and local agencies in
selecting toxic air pollutants for review or regulation. In one approach, a
specific list of toxic air pollutants is prepared. In the second approach,
the open-ended approach, the agency addresses any substance of concern.
Each of these approaches has advantages and disadvantages.
One advantage of defining a specific list of toxic air pollutants is
that an agency may scope or limit their air toxics program efforts and focus
their resources on the selected pollutants. The amount of research required
for identifying pollutant health effects associated with exposure to a
specific pollutant and emissions estimates might be less than for the open-
ended approach. Also, by defining a specific list of pollutants, the agency
may, in effect, let industry and the public know what to expect, and thereby
create a more cooperative atmosphere.
A disadvantage of defining a specific list of pollutants is that it may
be difficult to add new pollutants to the list. Depending on legal and
regulatory constraints, the additions may have to be approved by an
administrative board or by the legislature. Some pollutants may
inadvertently be left off the list, even though they represent a significant
potential for exposure and/or risk to the population. Conversely, the
longer the list becomes, the more resources must be devoted to data
management. Finally, there may be public controversy over which pollutants
are selected and the rationale for their selection.
2-1
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Further, some agencies have found it overly constraining to be limited
to a specific list of pollutants. An advantage offered by an open-ended
approach is that the agency can regulate emissions of any toxic substance
without undertaking a formal selection process.
One disadvantage of the open-ended approach is that the number of
pollutants addressed may become very large. Research into health effects
and emission rates for such a large number of pollutants may have to be
cursory. Data management may become resource-intensive. Also, industry may
not know what is expected and may be antagonistic when faced with
uncertainty in pollution control requirements. The public may express
concern that an open-ended approach does not define a specific control plan.
The advantages and disadvantages of each approach should be considered
by an agency when developing its air toxics program. One method is not
necessarily better than the other. Each State or local agency may have
existing circumstances that would fit one approach better than another.
Such circumstances include number of sources anticipated, available
resources, trends in new industrial growth and the nature of the air toxics
program as a whole (i.e., guidelines versus standards or control technology-
based requirements versus ambient air level-based programs).
2.2 METHODS OF SELECTING POLLUTANTS
To select pollutants, State and local agencies have used one or a
combination of the following methods:
• Health effects evaluation,
• Expected occurrence,
• Other lists,
• Internal assistance from divisions within the agency, and
t External assistance.
Several agencies have used various combinations of these methods to select
toxic air pollutants to list. The methods are discussed independently in
this section. Case histories of how agencies have selected pollutants
(Section 2.3) show how several of the methods have been combined to select
toxic air pollutants for review or regulation.
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2.2.1 Health Effects
One method of selecting toxic air pollutants is to examine the known or
expected health effects resulting from exposure to the pollutant. The
primary advantage of this method is that the pollutants which have the
potential to cause the health effects of concern are identified. However,
the major disadvantage to this method is that it does not identify
pollutants actually emitted in the area, and hence, resources could be
devoted to gathering information on pollutants that are not truly a problem
in the State or region. Using this method, a pollutant may be selected by
an agency if it is a known or suspected carcinogen, mutagen, or teratogen.
Also, noncarcinogens that may cause acute or chronic toxic effects may be
selected.
The major difficulty in selecting pollutants by health effects is
defining measures of toxicity. For carcinogens, several agencies involved
in toxicological research, including the National Toxicology Program (NTP)
and the International Agency for Research on Cancer (IARC), publish
descriptions of known and suspect carcinogens. NTP also publishes results
of mutagenicity and teratogenicity testing. The Occupational Safety and
Health Administration (OSHA) and the American Conference of Governmental
Industrial Hygienists (ACGIH) also identify substances as carcinogens.
Section 3.1 of this report more fully describes the types of health effects
data provided by these groups.
An advantage of using IARC information is that IARC uses a
classification system indicating the weight of evidence for classifying a
substance as a carcinogen. For example, the IARC classification method
divides the evidence that a substance produces cancer in humans into three
categories: sufficient, limited, and inadequate. A similar classification
system is provided for animal data. A State or local agency may include an
evaluation of the weight of evidence in their decision of whether or not to
select a pollutant for consideration in their air toxics program. EPA has
prepared a weight of evidence system, similar to that used by IARC. The
weight of evidence notation appears in health assessment documents in
conjunction with the unit risk factor. A discussion of the EPA weight of
evidence system can be found in the proposed EPA guidelines on carcinogenic
risk assessment in the Federal Register, November 23, 1984 (49 FR 46294).
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ACGIH has proposed a system to indicate carcinogenic potential of
experimental animal carcinogens. Specific criteria involving the dose and
route of exposure were defined to allow grouping of substances into high,
intermediate, and low carcinogenic potency. These criteria might also be
used by an agency in selecting pollutants of concern.
For substances with health effects other than carcinogenicity,
mutagenicity and teratogenicity, specific definitions of toxicity may not be
as clear. The National Institute for Occupational Safety and Health (NIOSH)
maintains the Registry of Toxic Effects of Chemical Substances (RTECS) data
base. RTECS contains, in addition to other data, information such as LDc0
and LCcQ. (The definitions of LDj-Q and LCgQ are given in the list of
abbreviations in this report.) An agency might choose to use these data to
determine whether a pollutant should be included on their list.
Some agencies might choose to list any substance with an LD5Q or LC5Q
of less than a predetermined value. The predetermined value chosen could be
the level below which no adverse health effects are expected to occur. LDr«
or LCj-Q may be especially useful to agencies evaluating short-term, acute
exposures during accidental releases of pollutants.
Finally, some State and local agencies have relied heavily on the ACGIH
list of Threshold Limit Values (TLV) to select pollutants of concern.
ACGIH publishes TLVs each year. TLVs are developed for chemical substances
which may be found in the workplace and may cause adverse health effects in
workers. The TLV is the concentration of each substance below which no
adverse health effects are expected to occur for workers exposed 8 hours per
day, 40 hours per week. However, as is indicated in the TLV listing, the
limits are intended for use in the practice of industrial hygiene as
guidelines or recommendations in the control of potential health hazards and
for no other use (e.g., in the evaluation or control of community air
pollution nuisances, in estimating the toxic potential of continuous,
uninterrupted exposures, etc.). These limits are not fine lines between
safe and dangerous concentrations and should not be used by anyone untrained
in the discipline of industrial hygiene. The ACGIH disclaims liability
with respect to the use of TLVs in a manner inconsistent with their stated
intended use.
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Notwithstanding the discussion of intended uses of TLV, State and local
agencies have used the TLV listing as a basis for pollutant selection. The
TLV list may be useful in identifying substances used in the workplace and
therefore having the potential to be emitted into the ambient air.
2.2.2 Expected Occurrence
A second method of selecting toxic air pollutants to list is by
evaluating the likelihood of a substance's use and emissions within a State
or region. This method identifies which pollutants are actually emitted or
anticipated to be emitted, but does not provide an indication of the
pollutant's toxicity.
Three data gathering methods may be used to determine which pollutants
are used/emitted: (1) literature reviews, (2) questionnaires,
(3) monitoring, and (4) source testing/stack sampling. Literature reviews
are less expensive than some other methods of data collection. Section 2.4
of this report presents sources of information that may be useful in
identifying potential sources of toxic air pollutants including an EPA
report now underway entitled "Compiling Air Toxics Emissions Inventories."
Reviewing EPA source assessment documents, emission factor documents and the
National Air Toxics Information Clearinghouse (NATICH) data base can
indicate the types of pollutants associated with different types of
industrial processes. Examples of the types of data available in the NATICH
data base are shown in Figures 2-1 and 2-2. The Clearinghouse also
publishes hard copy reports of data from State and local agencies and a
bibliography. These reports are listed in the preface of this report. The
bibliography includes abstracts for selected reports (e.g., source
assessments and emission factor documents) on current air toxics issues and
Federal Register notices concerning regulation of air toxics (see
Section 2.4).
Secondly, questionnaires requesting information on a facility's
production, use and storage of chemicals can indicate the types of
pollutants expected to be emitted. Surveys might be sent to all sources or
specific surveys could be developed for selected sources such as degreasing,
2-5
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fuel combustion, or surface coating facilities. By serving as a screening
tool, a production/use/storage questionnaire may best fit the needs of an
agency just beginning to develop an air toxics program. The results of the
production/use/storage questionnaire could focus the efforts of follow-up,
detailed questionnaires. The use of questionnaires is relatively less
expensive than other data gathering methods and allows agency personnel to
perform other duties while waiting for questionnaires to be returned. The
questionnaires could also serve as the cornerstone for air toxics emission
inventories.
A third way to determine which pollutants are emitted is to conduct
monitoring. Ambient monitoring can provide definitive indications of the
presence of a toxic pollutant in ambient air. However, proven ambient
monitoring and analytical methods have not yet been developed for all toxic
pollutants. Naturally occurring and secondary pollutants also need to be
considered. Monitoring is very expensive and may not be a necessary step in
pollutant selection or in the beginning stages of an air toxics program when
less expensive methods can be used.
Finally, source testing/stack sampling can indicate which pollutants
are actually emitted. Modeling of the measured emission rates can be used
to estimate ambient concentrations.
2.2.3 Other Lists
The lists of toxic pollutants prepared by State and local agencies and
EPA have been used by other State and local agencies as a basis for deciding
which toxic air pollutants to list. EPA's "List of 37", the pollutants
examined in EPA's national assessment of the air toxics problems, and the
EPA's Acute Hazards List are the most frequently used EPA lists. The EPA
"List of 37" includes those pollutants given priority for NESHAP study as
submitted to Congress in its 1982 deliberations for amending the Clean Air
Act (Table 2-1). The Acute Hazards List includes about 400 substances and
was published as part of the Agency's Chemical Emergency Preparedness
2
Program guidance document.
2-8
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TABLE 2-1. ERA'S LIST OF 37 POLLUTANTS
Acetaldehyde
Acrolein
Acrylonitrile
Ally! chloride
Benzyl chloride
Beryllium
Cadmium
Carbon tetrachloride
Chlorobenzene
Chloroform
Chloroprene
Coke oven emissions
o-, m-, p-Cresol
p-Dichlorobenzene
Dimethyl nitrosamine
(N-nitrosodimethylamine)
Dioxin
Epichlorohydrin
Ethylene dichloride
Ethylene oxide
Formaldehyde
Hexachlorocyclopentadiene
Maleic anhydride
Manganese
Methyl chloroform
(1,1,1 trichloroethane)
Methylene chloride
(dichloromethane)
Nickel
Nitrobenzene
Nitrosomorpholine
Perchloroethylene
Phenol
Phosgene
Polychlorinated biphenyls
Propylene oxide
Toluene
Tri chloroethylene
Vinylidene chloride
o-, m-, p-Xylene
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The EPA report entitled "The Air Toxics Problem in the United States:
An Analysis of Cancer Risks for Selected Pollutants" included an analysis
of cancer risk for the pollutants listed in Table 2-2. Pollutants from this
data set have been included in State and local agencies' lists of
pollutants, perhaps because of the national scope of the original EPA
report. That is, some of the pollutants examined in the EPA study may be
found in most urban areas. However, this list includes only chemicals
having some evidence of carcinogenicity and quantified risk estimates. An
agency might supplement this list with pollutants that can cause other toxic
effects.
Another list that has been used by State and local agencies is the EPA
list of acutely toxic chemicals (Acute Hazards List), found in the
November 1985 document entitled "Chemical Emergency Preparedness Program:
Interim Guidance." The program aids communities in evaluation of and
preparation for accidental release of acutely toxic chemicals. The list of
400 pollutants was prepared by searching the RTECS data base for chemicals
that met any one of the following criteria, based on data from mammalian
testing:
Exposure Route
Dermal
Oral
Inhalation
Acute Toxicitv Measure
Median lethal dose (LD5Q)
Median lethal dose (LD5Q)
Median lethal concentration
(LC5Q)
Value
<50 mg/kg
<25 mg/kg
<0.5 mg/1 (for
exposure up to
8 hours)
Also, if LC5Q or LD5Q data were not available, then LC-0 or LD.Q data were
used instead (LC.Q/LD.Q is the lowest reported concentration or dose of a
material at which some test animals died). The list of acutely toxic
chemicals is extensive (about 400 substances). An agency might prefer not
to list all of these chemicals, but might choose instead to review the list
for materials that may be emitted in their State or region.
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TABLE 2-2. POLLUTANTS ADDRESSED IN ERA'S REPORT ON
AIR TOXICS IN THE UNITED STATES3
Acrylamide
Acrylonitrile
Ally! chloride
Arsenic
Asbestos
Benzene
Benzo(a)pyrene
Benzyl chloride
Beryl 1i urn
1,3-Butadiene
Cadmium
Carbon tetrachloride
Chloroform
Chromium
Coke oven emissions
Diethanolamine
Dimethylnitrosamine
Dioctyl phthalate
Epichlorohydrin
Ethyl acrylate
Ethylene
Ethylene dibromide
Ethylene dichloride
Ethylene oxide
Formaldehyde
Gasoline vapors
Emissions from gasoline marketing facilities
4,4-Propylidene diphenol
Mel amine
Methyl chloride
Methylene chloride
4,4-Methylene dianiline
Nickel (subsulfide)
Nitrobenzene
Nitrosomorpholine
Pentachlorophenol
Perchloroethylene
Products of incomplete combustion
Polychlorinated biphenyls
Propylene dichloride
Propylene oxide
Radionuclides
Styrene
Terephthalic acid
Titanium dioxide
Tri chloroethylene
Vinyl chloride
Vinylidene chloride
*EPA report 450/1-85-001. The Air Toxics Problem in the United States:
Analysis of Cancer Risks for Selected Pollutants.
An
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Lists of toxic pollutants prepared by other agencies have been used to
prepare new lists. State and local agencies' lists now include from 11 to
more than 800 substances. While the lists may be all-inclusive for the
State or local agency for which they were prepared, they should not be
blindly adopted as a whole by another agency because the types of industries
present and the materials used and produced differ in different areas. The
derivation of each State's list could be checked by contacting the
particular State to help determine the similarity between common industry
types/source categories and, therefore, the applicability of the State's
list of pollutants" to another State or region. The NATICH on-line data
base, the hard copy report, and the Clearinghouse Newsletters may be used to
obtain lists of pollutants of concern in other States. Other States' lists
can serve as building blocks by identifying common pollutants. Discussions
with the appropriate personnel in a State or local agency may shed light on
the rationale for pollutant selection used by that agency.
2.2.4 Internal Assistance From Divisions Within the Agency
Another method of choosing pollutants to list is requesting
recommendations from agency divisions outside the air pollution group. The
water pollution division may be able to provide information on the most
frequently discharged water pollutants. The air pollution division may then
evaluate how those substances are used in industry and whether the
substances may be emitted or become airborne pollutants. The same approach
may be applied to information obtained by the State hazardous waste
division. RCRA permits contain lists of the constituents of hazardous waste
handled by a facility. The air pollution group could evaluate chemicals on
those lists for the potential for the pollutants to be emitted to the
atmosphere, based on their use in industry.
2.2.5 External Assistance
Several State agencies have requested assistance from individuals or
groups outside the agency during development of a list of pollutants or
after pollutant selection, as an external review. Toxicologists and
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physicians can assist in evaluating health effects of toxic pollutants.
Consultants and members of the academic community can perform technical
review of potential sources and quantities of the toxic pollutants listed as
well as review of the policy implications in listing pollutants. Personnel
from outside of the agency can give different perspectives on policy issues
and supplement the knowledge of agency staff.
Many agencies have requested industry participation in development of
their entire air toxics program, including a review of the list of
pollutants to be covered. These agencies report that the success of their
air toxics programs was due in part to industry personnel involvement and
increased awareness and cooperation. Participation by public groups,
citizens' committees, and environmental groups can yield the same results:
increased cooperation and understanding.
2.2.6 Commonly Selected Pollutants
An example of the types of pollutants selected by State and local
agencies is shown in Table 2-3. This list was compiled by reviewing the
pollutants listed by the seven agencies identified in the table and
selecting the fifty substances appearing most frequently on the lists.
Several of these agencies are included in the case histories in Section 2.3.
This list is not intended to be a recommended list of substances to
select. Rather, it shows which pollutants are commonly considered by
selected State and local agencies. It also does not include all of the
chemicals currently undergoing review by EPA.
2.3 CASE HISTORIES
Examples of the ways that State and local agencies have selected toxic
pollutants are presented in this section. In many cases, combinations of
several of the methods discussed in Section 2.2 have been used to select
pollutants of concern.
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TABLE 2-3. FIFTY MOST FREQUENTLY SELECTED TOXIC
POLLUTANTS IN SEVEN AGENCIES3
Acetaldehyde
Acrolein
Acrylonitrile
Arsenic
Aniline
Asbestos
Benzene
Benzidene
Benzyl chloride
Beryllium
1,3-Butadiene
Cadmium
Carbon tetrachloride
Chloroform
Chloroprene
Chromium
Cresol
p-Dichlorobenzene
Dioxane
Dioxin
Epichlorohydrin
Ethylene dibromide
Ethylene dichloride
Ethylene imine
Ethylene oxide
Formaldehyde
Hexachlorocyclopentadi ene
Hydrazine
Maleic anhydride
Manganese
Mercury
Methyl chloroform
Methylene chloride
Nickel
Nitrobenzene
N-nitrosodimethylamine
Perch!oroethylene
Phenol
Phosgene
Polychlorinated biphenyls
Polycyclic organic matter/
polycyclic aromatic hydrocarbons
Propylene oxide
Styrene
1,1,2,2-Tetrachloroethane
1,1,2-Trichloroethane
Trichloroethylene
Toluene
Vinyl chloride
Vinylidene chloride
Xylene
Agencies included are New Jersey Department of Environmental Protection,
North Carolina Department of Environmental Management, Puget Sound Air
Pollution Control Agency, Indiana Board of Health, Connecticut Department
of Environmental Protection, Philadelphia Air Management Services, and
California Air Resources Board.
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2.3.1 Examples of Methods Used by State/Local Agencies to Develop
Lists of Pollutants
A
Puqet Sound Air Pollution Control Agency
The Puget Sound Air Pollution Control Agency has listed 32 toxic air
pollutants. The Agency requested Material Safety Data Sheets (MSDS) from
sources in their jurisdiction for any materials used or produced at the
facility. (Material Safety Data Sheets are required by OSHA when a chemical
is considered hazardous as defined in the OSHA Hazard Communication
Standard, 29 CFR 1910.1200.) The requests were included as part of the
existing annual source registration process. The Agency then selected all
pollutants emitted in quantities of greater than one ton per year from any
facility (not individual emission point) as reported in the annual source
registration. There was no limit placed on the number of pollutants that
may be included on the agency's list.
Indiana State Board of Health5
The Indiana State Board of Health currently includes 28 pollutants of
concern in their air toxics program. The list of 28 was based on a study
conducted by a contract engineering research firm and a previous
questionnaire distributed by the Board of Health. This questionnaire
appears in the Appendix. The contractor identified 20 toxic pollutants of
concern for the State, based on reviews of the types of materials used in
the State and their physical/chemical characteristics. These 20 chemicals
were all volatile organic compounds. Eight additional compounds were
selected from the results of a questionnaire distributed by the Board of
Health. The Board of Health may choose to add some new substances to the
list and delete others as more information on the use and emission of these
chemicals is obtained.
The Board of Health has proposed an "intermedia" committee to include
representatives of the air, water, and land commission and a toxicologist to
deal with special toxics problems.
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Kentucky Division of Air Pollution Control
The Kentucky Division of Air Pollution Control has prepared draft
regulations for the control of air toxics emissions from new and existing
sources. A total of 102 chemicals have been selected as toxic air
pollutants of concern for existing sources. The list of chemicals was
developed from reviews of data in the existing criteria pollutant inventory
and from permit applications received during the past ten years.
The draft list of toxic air pollutants of concern for new sources
includes about 800 chemicals. Substances found in IARC, NTP, and ACGIH
lists were chosen to compile the list of toxics for new sources. At
present, not all of these substances may actually be emitted in the State;
the Division did not limit the group of pollutants selected to those
currently being emitted because they are planning for future growth of
industry in the State.
The Division accessed IARC, NTP, and ACGIH data through hard copy
reports from these specific groups. The Division notes, however, that they
can access the NATICH data base and DIALOG for air toxics data and
toxicological data, respectively, through computer terminals.
Connecticut Department of Environmental Protection. Air Compliance
,7,8
Uni1
The Connecticut Department of Environmental Protection (DEP) currently
includes over 800 substances on its list of toxic air pollutants. The list
was included in a previous Clearinghouse report: "Rationale for Air Toxics
Control in Seven State and Local Agencies." Three basic criteria were used
to develop the list:
• Substances identified as carcinogens or suspect carcinogens by
IARC, ACGIH, NCI, or NTP;
• Substances for which maximum allowable occupational exposure
limits have been established by the principal compilers of such
listings (ACGIH, OSHA, NIOSH); and
t Substances identified in Connecticut's Substitute House Bill 7204
(1983).
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In addition, a group of 16 chemicals of concern was identified in
conjunction with Connecticut's drinking water regulations and added to the
list of toxic air pollutants.
Connecticut's House Bill 7204 specified that the DEP must develop a
plan for control of air toxics. The Bill identified 47 substances of
concern. These substances were derived from the State of New York's list of
substances and specifically included the chemicals labeled as "high
toxicity" by the State of New York. The 16 substances identified in
conjunction with the State's drinking water regulations included substances
such as volatile organic compounds to which the public may be exposed
through inhalation (as the chemical vaporized from the water) as well as
through drinking water.
To resolve possible differences concerning identification of
carcinogens and other issues that may develop in later stages of the air
toxics program, the Connecticut air toxics program includes a seven member
Hazardous Air Pollutant Review Panel of health scientists appointed by the
Governor and other political leaders. The panel consists of a toxicologist,
an epidemiologist, and a physician specializing in environmental or
occupational medicine. The other members have experience in related fields
such as air pollution, biochemistry, or biostatistics.
7 9
Philadelphia Air Management Services '
Philadelphia Air Management Services (AMS) prepared a list of 99 toxic
air pollutants during development of their air toxics program. AMS prepared
this list by first referring to other lists, such as carcinogens identified
by ACGIH and NTP, and then by considering the likelihood that each pollutant
would be found in Philadelphia. The ACGIH lists of human carcinogens and
suspected human carcinogens were adopted by the AMS in their entirety.
Pollutants were selected from NTP lists by virtue of the fact that the
substance could be emitted as an air contaminant. For example, substances
such as saccharin were not selected from the NTP list because they were not
likely to be emitted to the atmosphere. Finally, AMS staff used engineering
judgment and their knowledge of the specific sources in the City of
Philadelphia to determine the likelihood that a substance could be found in
Philadelphia before selecting that substance for their list.
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To assist the AMS in developing the pollutant list and in evaluating
toxicological data, an ad hoc advisory committee was appointed by the Health
Commissioner. The seven-member committee consisted of health professionals
from academic, industry, and public interest groups in the fields of
toxicology, occupational medicine, and industrial hygiene. The committee
was also responsible for recommending ambient air quality guidelines for the
99 pollutants.
Washington Department of Ecology
The Washington Department of Ecology currently addresses 93 toxic
substances (or classes of substances). A preliminary screening study was
conducted to help identify those substances most likely to be emitted in the
State. A contract engineering research firm conducted a screening type
inventory for the State, based on a group of 56 common noncriteria
pollutants. The Department used the results of the screening inventory to
begin compiling the list of toxic air pollutants. Pollutants were added to
the beginning list of 56, based on 3 criteria: toxicity, the potential or
likelihood of use/emissions in the State of Washington, and the availability
of emission factors and related data. The toxicity data were obtained from
literature reviews and journal articles. The potential for emission was
based on the emission inventory screening study. Emission factors were
obtained through literature reviews. The final list of pollutants includes
both carcinogens and noncarcinogens.
New Jersey Department of Environmental Protection
The New Jersey Department of Environmental Protection (DEP) prepared a
list of 11 toxic volatile organic compounds (TVOCs) for regulation under
New Jersey Administrative Code - Title 7, Chapter 27, Subchapter 17,
"Control and Prohibition of Air Pollution by Toxic Substances." Three
criteria were used to select the 11 pollutants:
t The substance had to be relatively volatile so that there would be
a potential for atmospheric release and exposure,
• The substance must have been identified as a human or animal
carcinogen by IARC or NCI, and
• The substance must be produced in the United States in quantities
greater than 200,000 kg/year at the time of selection.
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The regulation (Subchapter 17) does not apply to TVOCs which were not added
to or deliberately formed in a raw material or a finished product, do not
exceed 0.25 percent by weight of any raw material or finished product, and
are not emitted from any source operation, storage tank or transfer
operation at a rate in excess of 0.1 Ib/hour.
12 13
North Carolina Division of Environmental Management (DEMI '
The list of 67 pollutants used by North Carolina Division of
Environmental Management (DEM) was compiled primarily from lists of other
agencies and through the use of a pollutant/Standard Industrial
Classification (SIC) Code index prepared for the State by a contract
engineering research firm. The pollutant/SIC code index was compiled based
on a literature review. North Carolina DEM conducted a preliminary
screening survey to determine which toxic pollutants were of concern in the
State. The pollutant/SIC code index was then compared to lists of existing
sources in the State to determine the likelihood that a given pollutant was
emitted in North Carolina. Existing sources were identified through the
criteria air pollutant inventory and directories of manufacturers.
Pollutants selected were those likely to be emitted to the atmosphere in
North Carolina and for which literature reviews indicated that adverse
health effects were associated with exposure to the chemical.
DEM personnel requested assistance from a toxicologist in the State
Health Department to review the toxicity and potential health effects of the
pollutants on the list. Also, the list was discussed with industry groups,
trade associations, and environmental groups. Finally, the DEM requested
that the North Carolina Academy of Sciences review their entire air toxics
program, including the list of toxic pollutants.
2.3.2 Discussion of Methods Used by State/Local Agencies to Select
Pollutants
State and local air pollution control agencies have used several
combinations of the specific procedures described in Section 2.1 to select
toxic air pollutants of concern. No method is necessarily better than the
others, nor is any method recommended over the others. The applicability of
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the methods to different situations and the resources required, however,
does vary. Each agency must select methods that are appropriate for their
special circumstances and that fit within their legal and regulatory
constraints.
For example, selecting pollutants solely from existing lists of
pollutants identified as potential health hazards (i.e., IARC lists, ACGIH
lists) may be quicker and require fewer resources than selecting pollutants
based upon review of pollutant-specific health effects data and their
expected occurrence in the area of concern. Therefore, using existing lists
may be appropriate when resources are very limited. However, selecting
pollutants without reasonable assurance that the substance is actually
emitted in the State or region may result in unnecessary expenditure of
resources through investigating health effects or attempting to locate
sources and designing a regulatory program. Screening studies may be useful
to identify pollutants most likely to be emitted. The NATICH on-line data
base permitting information file, as well as the hard copy report generated
from the data base, may also be used to identify pollutants associated with
various source types identified by SIC codes.
Alternatively, an agency might select pollutants based on health
effects, using independent research efforts instead of existing lists. In
this case, the agency may need to add toxicologists or pharmacologists to
the existing staff to provide the expertise required to evaluate toxicity
data. Requesting assistance from the State's health department or public
commissions may be a means of obtaining the required expertise without
adding to agency staff. Selecting pollutants through reviews of health
effects may be more time consuming, because of the research needed to
provide complete information, but the more accurate results may make the
effort worthwhile.
In another approach, not as focused on health effects, several State
and local agencies have used other State's lists and lists prepared by EPA
as a basis for selecting pollutants of concern. Using other agencies' lists
is a quick way to begin the pollutant selection process that requires less
effort on the part of agency staff and may be the best approach when
resources are limited or the agency is primarily concerned with conducting a
screening study. However, there may be pollutants unique to a given State
or region that are not included on other agencies' lists.
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In an effort to compile pollutant lists based in part on the quantities
of pollutants likely to be found in the air, emissions inventory
questionnaires have been used in some States to solicit information from
industrial sources about materials they use and manufacture. Pollutants to
be included in air toxics programs have then been selected, based on data
received from the completed questionnaires. This method of obtaining data
may be less time consuming than independent data gathering efforts performed
by an agency to determine which pollutants are possibly emitted. The use of
questionnaires requires expertise in carefully designing and planning of the
form to avoid problems caused by vague or poorly constructed questions,
however. For example, open-ended questionnaires requesting all available
data may result in too much information submitted for the agency to
adequately evaluate. On the other hand, some sources may not be able to
respond to the questionnaire at the required level of detail with
information they have readily available. In these cases, agency personnel
may be required to provide assistance to these sources or to conduct
independent research to identify pollutants. Thus, the decision to rely on
questionnaires to provide data on the types of pollutants emitted may depend
on availability of agency staff time and expertise to design an appropriate
questionnaire and to provide follow-up assistance.
2.4 DATA SOURCES USEFUL TO AGENCIES SELECTING POLLUTANTS
Many sources of information are available that State and local agencies
may find useful in helping them select toxic air pollutants for review or
regulation. Governmental agencies (EPA, DOE, NTP) and private organizations
(IARC) can provide information on health effects and potential sources of
toxic pollutants. This section of the report describes a few of the data
sources available.
Of the government agency information sources, the National Air Toxics
Information Clearinghouse (the Clearinghouse) offers a wide variety of
information on air toxics issues. The Clearinghouse was designed to provide
a forum for EPA and State and local agencies to exchange information on
toxic air pollutant program development, implementation, and related issues.
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Special reports, bibliographies, newsletters, and status reports of on-going
research are published through the Clearinghouse. In addition, the
information within the Clearinghouse is accessible through the NATICH
on-line data base. All data submitted by State and local agencies can be
viewed by accessing the data base. Information about the Clearinghouse is
available by calling the Clearinghouse staff, EPA, Pollutant Assessment
Branch, Research Triangle Park, North Carolina, (919) 541-5519, or
FTS 629-5519.
EPA publications such as chemical-specific health assessment documents,
published by EPA's Environmental Criteria and Assessment Office, provide a
complete description of health effects including carcinogenicity,
mutagenicity, teratogenicity, and noncarcinogenic toxic effects.
Availability of health assessment documents is announced in the Federal
Register. These documents are also listed in the Clearinghouse publication
entitled, "Bibliography of Selected Reports and Federal Register Notices
Related to Air Toxics," July 1986 (EPA 450/5-86-008).
In addition, EPA's Office of Air Quality Planning and Standards is
preparing a technical assistance document on air toxics inventory
development. This report, entitled "Compiling Air Toxics Emissions
Inventories" (EPA 450/4-86-010), is scheduled for publication in the summer
of 1986. It discusses considerations that should be addressed when
developing an air toxics emissions inventory and offers screening tools
which can be used as first steps in inventory development. Screening tools
include a "crosswalk" table that lists pollutants commonly associated with
specific SIC codes and a similar table listing SIC codes with pollutants
that might be expected to be emitted from such sources.
Abstracts on Health Effects of Environmental Pollutants (HEEPs) are
available via the Clearinghouse data base and may also prove helpful to
agency personnel researching health effects and environmental effects of
toxic air pollutants. Also available through Toxline in the National
Library of Medicine Medlars System, the HEEPs file is based on information
from Biological Abstracts, and Biological Abstracts/Reports. Reviews and
Management Literature. The file contains abstracts of journal articles
concerning environmental and human health effects of nonmedicinal chemicals.
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For a brief description of health effects, EPA's Chemical Hazardous
Information Profile (CHIPs) can be consulted. These documents give an
overview of health effects data for individual chemicals. CHIPs are
published by EPA's Office of Pesticides and Toxic Substances, and are listed
in the Clearinghouse bibliography cited above.
Documents in Toxics Integration Information Series (TIIS) and Toxics
Integration Policy Series (TIPS) are prepared through EPA's Office of Toxics
Integration. Subject areas covered by reports in these series include toxic
substances management, directories of Federal coordinating groups for air
toxics, information on grant activities and chemical activities status
reports.
The International Agency for Research on Cancer (IARC), a private
organization, prepares Monographs on the health effects and carcinogenicity
of chemical substances. These documents are a widely used reference for
identifying carcinogenic substances. A more complete description of the
Monographs is given in Section 3.1 of this report.
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3.0 POLLUTANT PRIORITIZATION
After a regulatory agency has selected pollutants of concern as air
toxics, a decision about whether to prioritize the listed pollutants should
be made. Some agencies that have selected a list of air toxics of concern
have decided that prioritization is neither necessary nor warranted.
Depending on the number of factors about each pollutant considered,
prioritization can be more costly and time consuming than some agencies may
be able to handle. Some agencies have found that they are able to regulate
air toxics successfully without prioritization.
In contrast, other agencies often find it useful to prioritize
pollutants. The reasons for prioritization vary but are usually one or more
of the following:
• Making a distinction for regulatory purposes among groups of
chemicals, such as carcinogens, noncarcinogens, and acutely toxic
chemicals;
t Identifying a subset of a larger list that will be addressed first
for regulatory purposes;
• Identifying pollutants that warrant further study due perhaps to
the fact that a pollutant is common in the State and little health
information is available; and
• Maximizing the effectiveness of available resources.
The reasons for prioritizing a selected list of air toxics will help
determine which method of prioritization should be used.
Prioritization systems vary in complexity depending on the number of
factors or prioritization criteria considered and the weighting given to
each factor relative to the others. This section will describe the use of a
single prioritization criterion as well as the use of several criteria.
Examples of each will follow the general discussion.
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3.1 PRIORITIZATION SYSTEMS BASED ON HEALTH EFFECTS
Several agencies use the single criterion of health effects to group
their list of pollutants into subsets. Different regulatory requirements
are applied to these subsets. The health effects considered may be limited
to carcinogenicity or may include additional effects such as mutagenicity,
teratogenicity, reproductive toxicity, acute toxicity, and chronic toxicity.
Several sources of information are available to help determine which
pollutants may be linked to a particular health effect. For example, the
following agencies provide lists of carcinogens, suspected carcinogens,
etc., as described below:
• National Toxicology Program (NTP) - Several agencies including EPA
participate in NTP, which is responsible for preparing annual
reports on carcinogens. The annual reports list substances or
technological processes which are classified as either "known to
be carcinogens" or "reasonably anticipated to be carcinogens."
• International Agency for Research on Cancer (IARC) - Part of the
World Health Organization, IARC publishes a series of reports
entitled, "IARC Monographs on,the Evaluation of the Carcinogenic
Risk of Chemicals to Humans." Through these Monographs, IARC
has classified chemicals, groups of chemicals, industrial
processes, and occupational exposure into the following groups:
Group 1 - carcinogenic to humans; Group 2A - less evidence of
carcinogenicity in humans than Group 1, but higher evidence
overall in humans and animals than Group 2B; Group 2B - lower
evidence overall in humans and animals than Group 2A; and
Group 3 - cannot be classified with respect to carcinogenicity in
humans. References to the IARC Monograph Series appear in the
July 1986 Clearinghouse report "National Air Toxics Information
Clearinghouse: Bibliography of Selected Reports and Federal
Register Notices Related to Air Toxics." The bibliography is
cited in the preface of this report.
t American Conference of Governmental Industrial Hygienists
(ACGIH) - ACGIH lists individual substances and substances
associated with industrial processes as confirmed human
carcinogens (Category Al) and suspected human carcinogens
(Category A2). ACGIH also offers guidelines on classifying
substances found to be carcinogenic in experimental animals. The
guidelines use classifications of high, medium, or low
carcinogenic potency in experimental animals, and examine ,g
respiratory, dermal, and gastrointestinal routes of exposure.
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• Occupational Safety and Health Administration (OSHA) - OSHA has
developed regulatory requirements for several toxic and hazardous
substances and many of these are designated "cancer-suspect
agents."
Sources of information identifying pollutants that have the potential
for causing other health effects are not as definitive as are those that
identify carcinogens. They require more interpretation on the part of the
user. Some sources of information on mutagenicity, reproductive toxicity,
and chronic and acute toxicity include:
• NTP Annual Plan - Each year, the NTP Annual Plan lists test
results for various mutagenic and reproductive toxicity tests, as
well as the schedule for testing various chemicals in the upcoming
fiscal year. Chemicals are identified in these reports only as
having positive or negative test results and not as being a
mutagenic or reproductive toxicant in humans.
• EPA Genetic Toxicology Program (GENE-TOX) - GENE-TOX identifies
and studies substances reported in the literature for potential
genetic effects. Chemical-specific information on the scheduling
of substances for the GENE-TOX study is found in the Registry of
Toxic Effects of Chemical Substances (RTECS). RTECS is available
on-line and in microfiche and hard copy forms. To obtain
information about this program, contact GENE-TQX Program, EPA,
401 M Street, TS798, Washington, D.C., 20460.10
• EPA Acute Hazards List - In December 1985, EPA published a list of
402 chemicals considered to have the potential to cause acute
health effects/
t ACGIH Threshold Limit Values (TLV) - ACGIH publishes a list of
TLVs and associated documentation for numerous chemicals to which
workers are exposed. TLVs include time weighted average values,
short term exposure levels, and ceiling values. '
• OSHA Permissible Exposure Limits - OSHA publishes "permissible
exposure limits" (PELs) for a specific list of chemicals, and
requires that employees' exposure cannot exceed these levels.,g
PELs include time weighted average values and ceiling values.
The initial PELs were based on ACGIH TLVs from the year 1968.
• National Institute of Occupational Safety and Health (NIOSH)
Recommended Standards - NIOSH has published several recommended
standards for safe exposure to levels of chemical hazards found in
the workplace. Documentation of these standards is available in
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the series of NIOSH reports entitled, "Criteria for a Recommended
Standard Occupational Exposure to (chemical)." These NIOSH
reports are cited in the Clearinghouse publication, "Bibliography
of Selected Reports and Federal Register Notices Related to Air
Toxics," EPA 450/5-86-008, July 1986.
Addresses in the References section of this report give adequate information
for obtaining any of the publications cited in Section 3.1.
3.2 EXAMPLES OF PRIORITIZATION BASED ON HEALTH EFFECTS
Examples of two State systems for evaluating health effects are
presented in this section. The first, developed by Maine's Bureau of
Health, is being used to prioritize pollutants for further assessment. The
second, developed by the Massachusetts Department of Environmental Quality
Engineering, has the potential to be used as a prioritization system, but is
not yet being used as such in Massachusetts.
?n
3.2.1 Maine Bureau of Health*
Following the selection of approximately 200 potentially toxic air
pollutants by the Maine Department of Environmental Protection (DEP), the
Maine Bureau of Health (BOH) developed a simple ranking system to prioritize
the chemicals for detailed risk assessments. Toxicity factors as well as
the potential for exposure to a given pollutant are the two components
incorporated in the BOH's ranking system. The ranking measures all the
pollutants against a standardized set of criteria, and assigns numerical
scores based on these criteria.
The toxicity component uses information cited in RTECS for the
following health categories: carcinogenicity, mutagenicity,
reproductive/teratogenic effects, and acute effects. Numerical values
ranging from zero to four (except for acute effects which are scored from
one to four) are assigned to each category based upon the likelihood that a
specific pollutant will cause a given adverse health effect in humans. A
maximum score of 16 could be obtained for a given pollutant. The toxicity
component is determined by adding the four individual category scores, and
3-4
-------
then adding to this sum the standard deviation of the four values. The
addition of the standard deviation is used to compensate for any wide
deviations which might occur in a given pollutant's health effects scores.
The exposure component consists of emissions estimates obtained from
responses to questionnaires sent by the DEP during the development of an air
toxics emissions inventory. Emissions from industrial, commercial,
residential, and mobile sources were estimated. The DEP followed up the
questionnaires with several site visits.
Given the many uncertainties associated with both the toxicity and
exposure components, a pollutant's toxicity score and emissions estimate in
pounds per year are multiplied to produce a final ranking score. Thus, the
pollutant with the highest score would receive the highest priority. If a
mixture is to be ranked in the system, the final scores of the individual
pollutants, based on their toxicity score and emissions estimate from the
mixture, are added to produce a final score for the mixture. The formal
risk assessment will evaluate the available literature on the entire
mixture. The individual pollutants will not be evaluated in the assessment,
rather they will be evaluated according to their position in the ranking
system. Table 3-1 illustrates the ranking of the top 11 hazardous
pollutants or chemical mixtures based on the combined toxicity and exposure
components.
Maine's Bureau of Health has cited several advantages and disadvantages
of this ranking system. Advantages include:
• The ranking system measures all the pollutants against a
standardized set of criteria,
• The ranking index provides a relative index of the pollutants'
potential health threats,
• The system is flexible enough to easily respond to additional
information, and
• The system has a method for ranking chemical mixtures.
Disadvantages identified by the Bureau of Health are:
• Data found in RTECS have not been peer reviewed, and it is also
possible that some important studies have not been included;
3-5
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TABLE 3-1. RANKING FOR TOP ELEVEN HAZARDOUS AIR POLLUTANTS/MIXTURES -
MAINE DEPARTMENT OF HUMAN SERVICES*"
Rank
1
2
3
4
5
6
7
8
9
10
11
Pollutant
(CAS Number)
Wood smoke
Toluene
(108-88-3)
Formaldehyde
(50-00-0)
Chlorine
(7782-50-5)
1,1,1-Trichloroethane
(71-55-6)
Cresolc
(1319-77-3)
Xylene
(1330-20-7)
Isobutyraldehydec
(78-84-2)
Tetrachl oroethyl ene
(127-18-4)
Acetaldehyde0
(75-07-0)
Phenol
(108-95-2)
Toxicity
Score
—
12.5
15.5
15.5
11.7
10.0
11.3
9.4
5.5
13.2
13.4
12.3
12.3
Emissions
(Ibs/yr)
—
2,511,623
1,271,400*
1,192,000°
1,433,003
1,496,539
1,192,000
1,091,274
1,788,000
708,050
596,000
601,180?
596,000°
Ranking Score
(Toxicity Score
x Emissions)
73,746,056
31,395,288
19,706,700?
18,476,000°
16,766,135
14,965,390
13,469,600
10,257,976
9,834,000
9,346,260
7,986,400
7,394,514*
7,330,800°
aTotal .
p
Emitted only as wood smoke component.
3-6
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• "Negative data" cannot be distinguished in RTECS from "no data";
• Biases are inherent in the health effects criteria, having the
potential to make the ranking disproportionately weighted against
pollutants which may be very toxic (specifically, since
carcinogenicity and reproductive toxicity are highly correlated
with mutagenicity, a compound is likely to score high in all three
areas);
• Important facets of a compound's potential toxicity, such as
chronic toxicity and synergistic effects, have not been explicitly
considered; and
• The estimate of a pollutant's Statewide emissions may be
inaccurate since little source testing has been done.
For more information on the Maine BOH ranking system, contact
Norman Anderson, Environmental Toxicology Program, Bureau of Health, State
of Maine, Station 11, Augusta, Maine 04333, (207) 289-5378.
3.2.2 Massachusetts Department of Environmental Quality Engineering
Massachusetts designed a health assessment methodology which is based
on a detailed review of scientific literature for acute/chronic toxicity,
carcinogenicity, mutagenicity, and developmental/reproductive toxicity. The
health assessments are used to select the "most appropriate occupational
limit" which is then adjusted by a number of uncertainty factors, depending
on the health data for specific chemicals, to derive an acceptable ambient
level. The Department of Environmental Quality Engineering has also
considered using the health effects scores to help set priorities among
chemicals and groups of chemicals for regulatory purposes. However, the
criteria and uses of such a prioritization scheme have not yet been fully
defined, and the Department is not using the health assessment scores to set
priorities. Such use may be made in the future and would be included in the
21
State's air toxics program implementation plan.
The first step in the Massachusetts process is known as the Chemical
Health Effects Assessment Methodology (CHEM). The purpose of CHEM is to
identify the range of adverse health effects associated with a given
3-7
-------
chemical compound. It is designed to evaluate the potential toxicity of a
large number of chemicals in a consistent and comprehensive manner, based on
weight of evidence, potency, and/or severity of effect. Chemical-specific
health effects data are recorded on worksheets for each category of health
effects, namely acute/chronic toxicity, carcinogenicity, mutagenicity, and
21
developmental/reproductive toxicity.
CHEM uses both primary (original experimental studies) and secondary
data (reviews and summaries of original studies). Review of primary data
sources is more time consuming on the part of Department toxicologists,
making the use of secondary data sources more practical. The Department has
relied on peer-reviewed secondary sources whenever possible, including NTP,
GENE-TOX, IARC, EPA (e.g., the Carcinogen Assessment Group's weight-of-
evidence classification), NIOSH, OSHA, and ACGIH., CHEM uses all valid
toxicity data documented by the sources consulted. This encompasses
qualitative and quantitative evidence, animal and human evidence, and
21
positive and nonpositive evidence.
The product of the health assessment is a score in each health effect
category for each chemical representing the relative hazard associated with
that chemical. Letter scores (A through E) are assigned rather than
numerical scores in order to emphasize the descriptive and comparative
nature of the scores, and to avoid the temptation to add or multiply health
effects scores from various categories. All health effects are considered
and accounted for independently of each other, and there is no attempt to
21
balance one type of effect against another.
In selecting the most appropriate occupational limit (MAOL), the
occupational limit which provides the best protection against the greatest
number of documented health effects, Massachusetts reviews occupational
limits developed by NIOSH, ACGIH, and OSHA. The MAOL is selected based on
relevance to documented health effects, degree of protection afforded,
importance of health effects accounted for, adequacy and comprehensiveness
of the data, limitations in the occupational limit, relevance to long-term
chronic effects, and whether the occupational limit is lexicologically
21
current.
3-8
-------
After selection, the MAOL is adjusted to derive the acceptable ambient
level (AAL). The MAOL is adjusted first to account for continuous
environmental exposure, exposure to children rather than adults, and
21
exposure to high risk, sensitive subpopulations. Thus, the AAL
MAOL x 5 davsa x 8 hrsa x 20 m3/24 hrs x 20 kgb x if - MAOL * 73.5
7 days 24 hrs 10 m3/24 hrs 70 kg 10
a - Extrapolation from 8 hours/5 days (work exposure) to
24 hour/7 days (continuous exposure)
b - Extrapolation from adult dose to child dose,
where:
20 m/24 hours = average adult ventilation rate
70 kg = average adult body weight
10 m/24 hours - average ventilation rate, 6 year old
20 kg = average body weight, 6 year old
c - Safety factor of 10 to account for sensitive populations.
Where all health effects have not been accounted for (e.g., carcinogenicity)
in establishing the occupational level, or there are insufficient data,
21
additional uncertainty factors are applied to the MAOL.
Table 3-2 presents an example of results of the Massachusetts CHEM
scores and acceptable ambient levels. The chemicals selected for Table 3-2
are the same chemicals listed in the same order as those that were presented
in Section 3.2.1, the top 11 ranking pollutants in Maine. This is done for
comparison only and does not reflect a ranking by Massachusetts.
For more information on the methodology for deriving CHEM scores and
AALs, contact Donna Bishop, Office of Research and Standards,
(617) 292-5510. For more information on use of AALs in the air program,
contact Jim Neely, Division of Air Quality Control, (617) 292-5629. The
address for both is Department of Environmental Quality Engineering,
1 Winter Street, Boston, Massachusetts 02108.
3-9
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3.3 MULTIPLE FACTOR PRIORITIZATION SYSTEMS
Several prioritization systems have been developed to rank pollutants
based not only on health effects, but also on factors not related to health.
The goals of these systems vary, and include identifying pollutants that
should undergo further regulatory assessment, suggesting pollutants that
warrant further environmental assessment, and identifying emission
levels that should trigger reporting. The factors considered in a system
depend on the goals the system was intended to serve. For that reason, this
section will describe several of the more complex prioritization systems
rather than presenting a general discussion. By reading these descriptions
and obtaining the reference documentation on systems of interest, State and
local agency users may be able to identify a system that could be modified
to serve their prioritization needs.
??
3.3.1 Modified Hazardous Air Pollutant Prioritization System (MHAPPSr
The Modified Hazardous Air Pollutant Prioritization System (MHAPPS) is
a computerized ranking method designed for screening hazardous air
pollutants for further assessment, possibly for future regulation. It is a
modified version of the Hazardous Air Pollutant Prioritization System,
23
developed in 1982. MHAPPS is designed to run on a personal computer.
MHAPPS ranks substances by scoring them for eight factors chosen to
reflect the concerns deemed important by EPA's Office of Air Quality
Planning and Standards. These eight factors are: oncogenicity,
mutagenicity, reproductive and developmental toxicity, acute lethality,
effects other than acute lethality, potential for airborne release,
bioaccumulation, and existing standards. The factor for potential for
airborne release is divided into two subfactors: production volume and
vapor pressure. These eight factors are weighted and combined into five
groups. The groups are: (1) carcinogenicity, (2) reproductive and
developmental toxicity, (3) toxicity, (4) exposure, and (5) standards.
Table 3-3 presents the subfactors, factors and groups used in HAPPS and
MHAPPS.
3-11
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TABLE 3-3. GROUPS, FACTORS AND SUBFACTORS USED IN HAPPS AND MHAPPS
22
Group
Factors
Subfactors
I. Carcinogenicity
A. Oncogenicity
B. Mutagenicity
II. Reproductive and
Developmental
Toxicity
A. Reproductive and
Developmental
Toxicity
III. Toxicity
A. Acute Lethality
B. Effects Other than
Acute Lethality
IV. Exposure
A. Potential for
Airborne Release
B. Bioaccumulation
V. Existing Standards A. Existing Standards
1. Production volume
(one MHAPPS option
lets users highlight
combustion products)
2. Vapor pressure
3-12
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MHAPPS ranks substances by proceeding through three levels, beginning
with the most detailed level and aggregating at successive levels to provide
a final single rank for each substance. At the first, most detailed level,
data are evaluated for the substances under consideration and a numerical
score is assigned for each of the eight factors. At the second stage, the
factor scores for closely related factors (see Table 3-3) are combined to
give group scores. Finally, group scores are combined to give the overall
score for the substance. The overall scores for different substances are
compared giving them numerical prioritizations or ranks. The remainder of
this section will describe (1) each of the eight factors, (2) how the factor
scores are combined to form group scores and group scores combined to give
an overall score, (3) the options MHAPPS allows users to select, and (4) the
limitations of MHAPPS.
The oncoqenicitv factor is based on data from the Registry of Toxic
Effects of Chemical Substances (RTECS) and the National Toxicology Program
(NTP) testing program schedule. Points are assigned for positive effects in
which the route of exposure is inhalation, oral, or dermal. Data from other
routes of exposure (e.g., subcutaneous) are not considered. The greatest
weight is assigned to effects resulting from inhalation exposure.
Additional weight is given when more than one specie is affected. The toxic
effects considered are carcinogenic, neoplastic, or an equivocal tumorogenic
response. Test species can be animal or human. Additional points are
assigned if the substance is scheduled for testing.
The mutagenicity factor is based on RTECS and NTP data as well. Points
are assigned for positive results in mammalian and nonmammalian test species
ip in vivo (oral, dermal, or inhalation) and in vitro tests. Additional
points are added if a substance is scheduled for testing in EPA's GENE-TOX
program.
The reproductive and developmental toxicitv factor is based on RTECS
data and the NTP Annual Plan. Scores are based on animal and human data via
inhalation, oral, or dermal exposure. An additional score is given if the
substance is scheduled for NTP testing.
The acute lethality factor scores are based on animal and human data in
RTECS. The route of exposure is inhalation, oral, or dermal and the data
3-13
-------
considered are of the form LD5Q, LCrg, LD.Q, or LC. Q for an exposure time of
less than or equal to 24 hours. The lower the concentration reported, the
higher the weight given.
For the effects other than acute lethality factor, data also come from
RTECS. Data are limited to animal and human data for which the route of
exposure is inhalation, oral, or dermal. Data are of the form TD.Q or TC,fi;
or LDLO, LD50, LCLO, or LC5Q where the length of exposure is greater than
24 hours.
MHAPPS uses three factors as surrogates for estimating the potential
for airborne release. These are production volume, existence as a
combustion product, and vapor pressure. Production volume and vapor
pressure data are taken from the on-line version of the Hazardous Substances
Data Base (HSDB). The designation as a combustion product is based on a
list of approximately 90 combustion products specially compiled for MHAPPS.
Originally, only production volume and vapor pressure were considered, but
an alternative was added to MHAPPS that allows the user to select an option
that also considers whether a substance is a combustion product. That
alternative allows the user to incorporate the potential for airborne
releases of a substance as a product of combustion in addition to the
substances' release during production (as indicated by production volume).
The bioaccumulation factor is based on the octanol/water partition
coefficient which is related to the tendency of a substance to accumulate in
fat rather than in water and hence, to accumulate in animals. This
coefficient is found in HSDB.
The existing standards factor was included based on the premise that
establishment of a standard or recommended occupational level requires a
finding of potential toxic effects. Such a finding was considered to be an
important sign that a substance might need consideration in more detail.
The values considered are the OSHA time weighted average (TWA) or the
ACGIH-threshold limit value (TLV) TWA if there is no OSHA standard. These
values are found in RTECS.
Scores for each factor are "normalized" so that the maximum score for
any factor is one. Normalization is accomplished by dividing a numerical
factor score by the highest possible score that factor could receive. This
normalization procedure was adopted primarily to aid in the assignment of
interfactor and intergroup weights.
3-14
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After scores are assigned for each factor, certain factors that are
either closely related or that are surrogates for the same effect of real
interest are combined to form group scores. Table 3-3 shows the factors
that comprise the five groups. In assigning a group score, the factor
scores are combined, but factors are not always treated equally. For
example, in the carcinogenicity group, oncogenicity is weighted more heavily
than mutagenicity because the strongest evidence for mutagenicity was
considered to be a less reliable indicator of a substance's carcinogenic
potential than the strongest evidence for oncogenicity. The exposure group
weights the potential for airborne release ten times higher than
bioaccumulation since the potential for airborne release was considered to
be more indicative of the need for additional study than the potential to
bioaccumulate.
The final step in MHAPPS scoring is to combine the five group scores
into one overall score. This task is difficult because it requires that
decisions be made as to the relative importance of dissimilar elements. In
MHAPPS, all health-related groups are treated equally. The exposure group
is given weight equal to the sum of the weights of three health-related
groups. The standards group is weighted at one-tenth the weight of the
exposure group.
MHAPPS includes three different scoring alternatives that can be used
to compare how selection of any one alternative affects the rank of a
substance. The first alternative, MHAPPS1, weights animal and human test
data equally. This alternative was added because, in many cases, animal
test results are considered more reliable than data gathered in human
epidemiological studies.
MHAPPS2, the second user-selected alternative, was developed to
emphasize short term exposure. This alternative affects the weighting of
the factors within the toxicity group and the intergroup weights as well.
Within the toxicity group, acute lethality is weighted more heavily than
effects other than acute lethality. For the intergroup weights used to
determine the overall score for a substance, the toxicity group receives the
greatest emphasis. Carcinogenicity is not considered (i.e., it is weighted
as zero). As with the other MHAPPS alternatives, the exposure group and the
sum of the health-related groups receive equal weight.
3-15
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The third alternative, MHAPPS3, is designed to characterize the
potential for exposure more accurately than by relying on production volume
and bioaccumulation alone. MHAPPS3 assigns a higher weight for products of
combustion than those substances would receive based on production volume
alone.
Table 3-4 illustrates sample rankings in MHAPPS and the three MHAPPS
alternatives for the 11 pollutants listed in Section 3.2.1.
Before using any prioritization system, users need to be aware of the
system's limitations in order to properly interpret the results. Ideally, a
full range of lexicological and epidemiological information coupled with
detailed estimates of emissions and human exposure would be available for
use in regulatory decisions. Since this is rarely the case, EPA developed
MHAPPS as a procedure for initially prioritizing substances on the basis of
limited, readily available information so that resources for detailed
studies can be allocated efficiently to substances anticipated to present
significant air pollutant problems.
Data for MHAPPS come primarily from RTECS, a concise, easily used
summary of toxic effects that is regularly updated. The major drawback of
the use of RTECS is that the data are not reviewed for quality or accuracy.
This significantly increases the number of false positives in the final
ranking. A single report in RTECS for a given effect receives equal weight
as multiple reports for that effect. This is the case because a single,
high quality study can be equal in part to several studies of lesser
quality, and, without a more detailed assessment, these two situations
are treated equally. Finally, it is important to note that a low score in
MHAPPS and in the MHAPPS alternatives does not necessarily indicate a low
potential hazard. It may indicate that no data or very limited data were
available.
When this report was published, the documentation for MHAPPS was in
draft form. For more information on the availability of MHAPPS, contact
EPA's Pollutant Assessment Branch, MD-12, Research Triangle Park, North
Carolina 27711, (919) 541-5519, FTS 629-5519.
3-16
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TABLE 3-4. SAMPLE MHAPPS RANKINGS'
Pollutant
(CAS Number)
Wood smoke
Toluene
(108-88-3)
Formaldehyde
(50-00-0)
Chlorine
(7782-50-5)
1,1,1-Trichloroethane
(71-55-6)
Cresol
(106-44-5)
Xylene
(1330-20-7)
Isobutyraldehyde
(78-84-2)
Tetrachl oroethyl ene
(127-18-4)
Acetaldehyde
(75-07-0)
Phenol
(108-95-2)
Rank
MHAPPS MHAPPS 1
Not in MHAPPS
Not in MHAPPS
4 2
239 297
Not in MHAPPS
95 119
Not in MHAPPS
416 485
64 47
10 10
7 11
MHAPPS2
data base
data base
7
214
data base
64
data base
522
129
14
10
MHAPPS3
3
247
98
416
67
11
7
Ranking shown is relative to 610 compounds currently in the MHAPPS data
base. The 11 pollutants listed here were chosen for comparison purposes
from the top 11 list of pollutants identified by Maine (Section 3.2.1).
A lower score indicates a higher priority.
This information is for p-cresol. Section 3.2.1 refers to all isomers
of cresol.
3-17
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3.3.2 Multimedia Environmental Goals
The procedure for establishing Multimedia Environmental Goals (MEGs)
was developed in 1977 by EPA's Industrial Environmental Research Laboratory
(IERL) which is now known as the Air and Energy Engineering Research
Laboratory (AEERL). The MEGs system was revised in the early 1980s and was
renamed Monitoring Trigger Levels (MTLs). Work on MTLs was never published
UPC- the project is no longer active. The MEGs system is described here
because, even though EPA no longer actively supports the system, it still
has useful principles for pollutant prioritization.
The development of MEGs represents an attempt to evaluate and rank a
large number of pollutants for environmental assessment. MEGs are levels of
significant contaminants or degradation products in ambient air, water, or
land or in emissions or effluents conveyed to the ambient media, that are
judged to be (1) appropriate for preventing certain negative effects in the
surrounding populations or ecosystems, or (2) representative of the control
24
limits achievable through technology.
Both ambient MEGs (AMEGs) and discharge or emission MEGs (DMEGs) were
developed. AMEGs describe maximum acceptable concentrations of chemicals in
the ambient media, based on potential ecological effects or on predicted
toxic levels for humans. AMEGs are derived from three data sources:
(1) the most stringent current or proposed ambient standards, (2) empirical
data on human health and ecological effects, and (3) the relationship
between the chemical's carcinogenic or teratogenic potential and the
24
acceptable risk from continuous exposure.
Emission or discharge MEGs (DMEGs) are acceptable levels of
contaminants in point source or fugitive emissions. Streams may be gaseous,
aqueous, or solid in nature. DMEGs are based on human health effects and
ecological effects. The health effects addressed are predominately acute
toxic effects, but also carcinogenicity and teratogenicity. Ecological
effects include vegetation damage, aquatic toxicity, and groundwater
24
contamination potential.
MEG values may be calculated from several different types of toxicity
data such as, acute lethal dose in rats or other animals, levels associated
with significant incidence of tumors, concentrations causing tainting of
3-18
-------
fish, and lethal concentrations to fish. For any given chemical, there may
be available only one of the possible data types or there may be several.
Thus, multiple MEG values can be calculated. MEGs are presented using a
coding system to identify: (1) the medium (air, water, or land) for which
the value applies; (2) the effect to be avoided (e.g., human health effects,
carcinogenic effects, or ecological effects); and (3) the basis for
derivation of the MEG.
The primary advantage of the MEGs system is that MEGs can be defined
based on a variety of data items, making it a workable system even when some
types of data are not available. The primary disadvantage is that the MEGs
system does not weigh the various effects against each other in arriving at
a final score.
3.3.3 CERCLA Reoortable Quantities25
Under the Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA) of 1980, persons in charge of vessels or facilities
from which hazardous substances have been released into the environment in
quantities that are equal to or greater than the reportable quantities (RQ)
must immediately notify the National Response Center of the release. The
phrase "released into the environment" is broadly defined, including
substances that seep into the ground, volatilize into the atmosphere, or
enter surface water. Excluded from this definition are releases confined to
the workplace, emissions from a vehicle or pumping station, a nuclear
release, and normal application of fertilizers. Reportable quantitites were
established under Section 102(b) of CERCLA (40 CFR Part 302) and under the
Clean Water Act for discharges of hazardous substances into navigable waters
(40 CFR Part 117).
There are five RQ levels: 1, 10, 100, 1000, and 5000 pounds. Five
primary criteria are considered and one of the five RQ levels is selected
for each criterion. The primary criteria considered are aquatic toxicity,
mammalian toxicity, ignitability, reactivity, and chronic toxicity. Thus,
each substance receives several RQ values and the lowest becomes the single
"primary criteria" RQ. The bases for the primary criteria are listed in
Table 3-5.
3-19
-------
TABLE 3-5. PRIMARY CRITERIA FOR CERCLA REPORTABLE QUANTITIES (RQs)
Aquatic
RQ (pounds)
1
10
100
1000
5000
RQ (pounds)
1
10
100
1000
5000
Toxicity Ignitability (fire)
mq/1 RQ (pounds)
LC50 <0.1 1 - No 1-pound RQs on basis of
ignitability
0.1 < LCj-Q <1 10 - Pyrophoric or self-
ignitable
1 < LC5Q <10 100 - FPcc <100°F, BP <100°F
10 < LC5Q <100 1000 - FPCC <100°F, BP >100°F
100 < LC5Q <500 5000 - FPCC = 100°F - 140°F
FP = Flash point using closed cup
test
BP = Boiling point
MAMMALIAN TOXICITY
Oral (mq/kq) Dermal (mq/ka) Inhalation (ppm)
LD5Q <0.1 LD5Q <0.04 LC5Q <0.4
0.1 < LD5Q <1 0.04 < LD5Q <0.4 0.4 < LC5Q <4
1 < LD5Q <10 0.4 < LD5Q <4 4 < LC5Q <40
10 < LD5Q <100 4 < LD5Q <40 40 < LC5Q <400
100 < LDcn <500 40 < LDCrt <200 400 < LCCrt <2000
3-20
-------
TABLE 3-5. (Continued)
RQ (pounds)
1
10
100
1000
5000
REACTIVITY
With Water
No 1-pound RQs on the
basis of reactivity
Inflames (e.g., Na, CaC2)
Extreme reaction
(e.g., S03)
High reaction (e.g., oleum)
Moderate reaction
(e.g., NH3)
Self-Reaction
No 1-pound RQs on the
basis of reactivity
Extreme self-reaction; may
cause explosion or
detonation
High; may polymerize;
requires stabilizer
Moderate; contamination
may cause polymerization;
no inhibitor required
Slight; may polymerize
with low heat release
RQ (pounds)
1
10
100
1000
5000
CHRONIC TOXICITY'
Composite Score
81 - 100
41 - 80
21 - 40
6 - 20
1 - 5
Chronic toxicity is defined as toxicity due to repeated or continuous
exposure from a single release or multiple releases of a designated
hazardous substance.
3The chronic toxicity ranking system reflects two attributes of a chemical:
(1) the minimum effective dose (MED) levels for a given effect following
chronic exposures by alternative environmental media (air, water), and
(2) the type of effect at the MED. Dose and effect are both given rankings
from 1 to 10 and these are multiplied to get the final composite score.
3-21
-------
Secondary criteria are biodegradation, hydrolysis, and photolysis.
These criteria reflect the natural dissipation processes which may reduce
the risk posed by the release of a hazardous substance. Secondary criteria
can be used to raise the primary criteria RQ. If the substance degrades
rapidly to a less harmful substance, the primary criteria RQ is raised one
level (e.g., from 10 pounds to 100 pounds).
The main advantage to the RQ system is that it is easy to apply and
does not require highly trained experts in toxicology to evaluate data.
There are two main limitations to the RQ system. First, RQs do not use any
measure of carcinogenic potential. Mammalian toxicity refers to acute
toxicity, rather than chronic. However, EPA is in the process of developing
adjusted RQs for potential carcinogens. Second, RQs do not weight the five
criteria relative to one another to arrive at a final score. The lowest RQ
for any of the five primary criteria becomes the RQ.
Table 3-6 lists RQs for the 11 pollutants used as examples in this
section. The responsibility for RQs falls under EPA's Response Standards
and Criteria Branch, Emergency Response Division (WH-548B), U. S.
Environmental Protection Agency, 401 M Street, S.W., Washington, D.C. 20460.
?7
3.3.4 Oak Ridge National Laboratory Chemical Scoring System
The Oak Ridge National Laboratory (ORNL) developed the Chemical Scoring
System for the Assessment Division of EPA's Office of Pesticides and Toxic
Substances to assist in grouping chemicals so that those with the greatest
need for control or testing under TSCA were identified and reviewed first.
It is a screening tool and hence is a compromise between completeness and
speed. The ORNL system served as the basis for the Hazardous Air Pollutant
Prioritization System (HAPPS) from which the MHAPPS system discussed above
was developed. Many ORNL features were greatly simplified in arriving at
HAPPS, and were modified to focus on air pollutants. The ORNL system is a
multi-media prioritization system.
The ORNL system consists of five main components with individual
factors that make up each component. A score is calculated for each of the
total 34 factors. Table 3-7 lists the five components and factors
associated with each.
3-22
-------
TABLE 3-6. CERCLA REPORTABLE QUANTITIES FOR ELEVEN EXAMPLE POLLUTANTS25
Pollutant (CAS Number) RQ (pounds)
Wood smoke (No RQ listed)
Toluene (108-88-3) 1000
Formaldehyde (50-00-0) 1000*
Chlorine (7782-50-5) 10
1,1,1-Trichloroethane (71-55-6) 1000
Cresol (1319-77-3) 1000
Xylene (1330-20-7) 1000
Isobutyraldehyde (78-84-2) (No RQ listed)
Tetrachloroethylene (127-18-4) 1*
Acetaldehyde (75-07-0) 1000
Phenol (108-95-2) 1000
* ' ' ' —~-~~ — —
indicates RQ is subject to change when assessment of potential
carcinogenicity and/or chronic toxicity is completed.
3-23
-------
TABLE 3-7. INDIVIDUAL SCORING SYSTEMS OF EACH ORNL
CHEMICAL SCORING SYSTEM COMPONENT
BIOLOGICAL TOXICITY I
Carcinogenicity
Mutagenicity
Embryotoxicity and fetotoxicity
Reproductive effects (mammalian)
BIOLOGICAL TOXICITY II
Chronic Toxicity Subcomponent
Chronic toxicity to terrestrial
animals
Severity for chronic effects to
terrestrial animals
Chronic toxicity to aquatic animals
Severity for chronic effects to
aquatic animals
Chronic toxicity to plants,
bacteria, and fungi
Severity for chronic effects to
plants, bacteria, and fungi
Acute Toxicity Subcomponent
Acute toxicity to terrestrial
animals
Acute toxicity to aquatic animals
Acute toxicity to plants, bacteria,
and fungi
ENVIRONMENTAL FATE
Bioaccumulation
Persistence
Vapor pressure
Aqueous solubility
PRODUCTION AND RELEASE
U.S. net production
Number of producers
Release rate
Release mode
HUMAN EXPOSURE
Occupational Subcomponent
EFWEb
Quantity of chemical potentially
available for worker exposure
through industrial use
Exposure at the manufacturing site
Quantity of chemical processed by
customers
Potential occupational exposure
level0
Exposure route
Exposure form
Consumer Subcomponent
Number of consumers
Quantity of chemical
Exposure frequency
Exposure intensity
Penetrability
Exposure route
Exposure form
Includes reproductive effects.
Equivalent full time workers exposed.
cThis scoring system should only be used if no data are available to use the
potential occupational exposure level scoring system (see footnote d).
If data is available to use this scoring system, do not use the exposure at
the manufacturing site scoring system or the quantity of chemical processed
by customers scoring system (see footnote c).
3-24
-------
After scores are calculated for each factor, these are combined within
the components and a total score for each component is calculated. Component
scores are not combined into one score because it was felt that a single
comprehensive score might not reflect the true potential hazard of a
chemical.
Although the ORNL scoring system is based primarily on objective
criteria, subjectivity in the form of professional judgment plays an
important role, more so than in the other systems described. Each
individual scoring system has the potential for the input of professional
judgment, in that an estimate of effect can be made when there are no data
from which to make an evaluation. Professional judgement is also required
to a significant degree in the final evaluation of a chemical after scoring
is completed.
As with MHAPPS, it is important to emphasize that a low component score
total does not necessarily indicate a low hazard potential, but could
indicate that no data were available.
3.4 COMPARISON OF MHAPPS, MEGs, RQs, AND ORNL SYSTEMS
Table 3-8 presents a comparison of the factors addressed by the four
prioritization systems discussed in this section. For each health-related
factor, the table lists the types of species and route of exposure for which
health data are considered. For the other nonhealth factors, the table
lists the specific factors considered by each system for each general
factor.
Table 3-9 compares four procedural features of the four systems.
Knowledge of these features would be important to any agency that may be
making a decision about using one of these systems. Table 3-9 indicates
whether expert judgment is necessary to interpret data for scoring. Expert
judgment in this case means someone who is trained in the field of
toxicology. The table also compares the four systems with respect to the
resource requirements necessary for data gathering. The high, medium, and
low classifications used are relative to four systems presented. Resource
requirements include the relative amount of staff time required to assemble
and extract the necessary data.
3-25
-------
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POLLUTANT PRIORITIZATION SYSTEMS
MHAPPS
MEGs
RQs
ORNL
Is expert judgment
necessary to interpret
data for scoring?
No
Yes
No
Yes
Are unrelated factors
combined in scoring?
Yes
No
No
No
Is documentation Draft
available?
Resource requirements Medium
necessary for data
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medium, low
classifications,
relative to each other.)
Are multi-media routes Yes
of exposure considered?
Are environmental No
effects other than human
and animal health
effects considered?
Yes
High
Yes
Low
Yes
High
Yes
Yes
Yes
No
Yes
Yes
3-28
-------
REFERENCES
1. American Conference of Governmental Industrial Hygienists. TLVs
Threshold Limit Values for Chemical Substances in the Work Environment
Adopted by ACGIH with Intended Changes for 1985-86. ACGIH,
6500 Glenway Avenue, Building D-5, Cincinnati, Ohio 45211.
2. U. S. Environmental Protection Agency. Chemical Emergency Preparedness
Program. Interim Guidance. December 1985. U. S. Environmental
Protection Agency, 401 M Street, S.W., Washington, D.C. 20460.
3. U. S. Environmental Protection Agency, Office of Air and Radiation.
The Air Toxics Problem in the United States: An Analysis of Cancer
Risks for Selected Pollutants. EPA 450/1-85-001. May 1985. U. S.
Environmental Protection Agency, 401 M Street, S.W., Washington, D.C.
20460.
4. Radian Corporation. Telecon. P. A. Cruse (Radian), and John Anderson
(Puget Sound Air Pollution Control Agency). May 1986a, July 1986.
5. Radian Corporation. Telecon. P. A. Cruse (Radian), and
Eugene Dumitriu (Indiana State Board of Health). May 1986b, July 1986.
6. Radian Corporation. Telecon. P. A. Cruse (Radian), and Hisham Saaid
(Kentucky Division of Air Pollution Control). May 1986c, July 1986.
7. U. S. Environmental Protection Agency, Pollutant Assessment Branch.
National Air Toxics Information Clearinghouse: Rationale for Air
Toxics Control in Seven State and Local Agencies. EPA 450/5-86-005.
August 1985. U. S. Environmental Protection Agency, MD-12, Research
Triangle Park, North Carolina 27711.
8. Radian Corporation. Telecon. P. A. Cruse (Radian), and John Gove
(Connecticut Department of Environmental Protection, Air Compliance
Unit). July 1986.
9. Radian Corporation. Telecon. P. A. Cruse (Radian), and Nick Ciceretti
(Philadelphia Air Management Services). July 1986.
10. Radian Corporation. Telecon. P. A. Cruse (Radian), and Kathy Bens
(Washington Department of Ecology). July 1986.
11. U. S. Environmental Protection Agency, Pollutant Assessment Branch.
Study of Selected State and Local Air Toxics Control Strategies,
EPA 450/5-82-006. October 1982. U. S. Environmental Protection
Agency, MD-12, Research Triangle Park, North Carolina 27711.
R-l
-------
12. Radian Corporation. North Carolina Air Toxics Survey: Identification
of Pollutants of Concern and Potential Emission Sources.
November 1985. North Carolina Division of Environmental Management,
Raleigh, North Carolina 27611.
13. Radian Corporation. Telecon. P. A. Cruse (Radian), and Dwight Greene
(North Carolina Division of Environmental Management). June 1986.
14. U. S. Department of Health and Human Services, National Toxicology
Program. Third Annual Report on Carcinogens, Summary. NTP 82-330.
September 1983. NTP, Research Triangle Park, North Carolina 27711.
15. World Health Organization, International Agency for Research on Cancer.
IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals
to Humans: Chemicals, Industrial Processes, and Industries Associated
with Cancer in Humans. IARC Monographs, Volumes 1 to 29, Supplement 4,
October 1982. WHO Publications Center, 29 Sheridan Avenue, Albany,
New York 12210.
16. U. S. Code of Federal Regulations, 29 CFR 1910 Subpart Z. Occupational
Safety and Health Standards: Toxic and Hazardous Substances. Office
of the Federal Register, Washington, D.C.
17. U. S. Department of Health and Human Services, National Toxicology
Program. National Toxicology Program Fiscal Year 1984 Annual Plan.
NTP, Research Triangle Park, North Carolina 27711.
18. National Institute of Occupational Safety and Health. Registry of
Toxic Effects of Chemical Substances. Quarterly Microfiche edition,
on-line through MEDLARS, and in hard copy form. NIOSH, Cincinnati,
Ohio 45226.
19. ACGIH Documentation of the Threshold Limit Values. ACGIH Publications
Office, 6500 Glenway Avenue, Building D-5, Cincinnati, Ohio 45211.
20. Anderson, Norman T. Ranking Hazardous Air Pollutants for Formal
Evaluation. March 15, 1985. State of Maine, Department of Human
Services, Augusta, Maine 04333. Personal communication. A. S. Pel land
(Radian) and Norman Anderson. August 19, 1986.
21. Commonwealth of Massachusetts, Department of Environmental Quality
Engineering. The Chemical Health Effects Assessment Methodology and
The Method to Derive Acceptable Ambient Levels. Document for Peer
Review. June 1985. Boston, Massachusetts 02108.
22. U. S. Environmental Protection Agency, Pollutant Assessment Branch.
Revision of the Hazardous Air Pollutant Prioritization System. Draft
Report. April 1986. U. S. Environmental Protection Agency, MD-12,
Research Triangle Park, North Carolina 27711.
R-2
-------
23. U. S. Environmental Protection Agency, Pollutant Assessment Branch.
Hazardous Air Pollutant Prioritization System (HAPPS). October 1982.
U. S. Environmental Protection Agency, MD-12, Research Triangle Park,
North Carolina 27711.
24. U. S. Environmental Protection Agency, Industrial Environmental
Research Laboratory. Multimedia Environmental Goals for Environmental
Assessment, Volume I - EPA 600/7-77-136a, November 1977; Volume II -
MEG Charts and Background Information - EPA 600/7-77-136b,
November 1977; Volume III - MEG Charts and Background Information
Summaries - EPA 600/7-79-176a, August 1979; and Volume IV - MEG Charts
and Background Information Summaries - EPA 600/7-79-176b, August 1979.
U. S. Environmental Protection Agency, IERL, Research Triangle Park,
North Carolina 27711.
25. U. S. Environmental Protection Agency, Emergency Response Division.
Notification Requirements; Reportable Quantity Adjustments.
50 FR 13456. April 4, 1985. U. S. Environmental Protection Agency,
401 M Street, S.W., Washington, D.C. 20460.
26. U. S. Environmental Protection Agency, Office of Emergency and Remedial
Response. Research and Development Methodology and Guidelines for
Ranking Chemicals Based on Chronic Toxicity Data. November 1984.
U. S. Environmental Protection Agency, Cincinnati, Ohio 45268.
27. Oak Ridge National Laboratory. Chemical Scoring System Development.
Draft Report. December 1980. Oak Ridge National Laboratory, Oak
Ridge, Tennessee 37830.
R-3
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APPENDIX:
STATE OF INDIANA AIR TOXICS QUESTIONNAIRE
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STAT&
INDIANA
STATE BOARD OF HEALTH
AN EQUAL OPPORTUNITY EMPLOYER
March 7, 1986
INDIANAPOLIS
Address Reply to:
Indiana Slate Board of Health
1330 \Vest Michigan Street
P. 0. Box 1964
Indianapolis. IN 46206-1964
Gentlemen:
The Air Pollution Control Division (APCD) of the Indiana State
Board of Health seeks to protect your health from harmful substances
emitted into the atmosphere. Because of the growing concern over the
potential health effects of toxic compounds, particularly those related
to cancer, this agency is conducting a survey to help determine if a
condition of air pollution exists.
In order to help us estimate the potential for cancer risk in
your area, please complete the enclosed form and return it to the APCD
within TEN DAYS. For each compound used* state the quantity and the
emissions. Confidential data will be handled in accordance with
established legal procedures. If you think other chemicals on your
plant property may be a potential health risk, please list them along
with the data at the bottom of the form. If you do not use* any of
these compounds, please so indicate on the form, then sign, date, and
return it to the APCD. It is important that you return the
questionnaire even if no compounds are used. This will aid our planning
and remove your company from our list of potential sources.
Indiana Code 13~1-1-4(B) (3) permits the State to request this
type of information. If you have any questions or problems in
completing the questionnaire, please contact the inspector at either the
address or telephone number below. Your cooperation is appreciated.
Return Questionnaire to:
Andrew E. Gate
Air Pollution Control Division
1330 West Michigan Street
Indianapolis, IN 46206
317/633-0660
Very truly yours,
HarryMj. Williams, Director
Air Pollution Control Division
*Stored, transported, transshipped, generated as a product or by-
product, consumed in production, lost to the atmosphere or waste
stream, reclaimed, repackaged, or otherwise handled in some fashion.
1831 - A CENTURY OF SERVICE - 1981
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TOXIC COnPOUHDS OUESTlOHHflIRE
Reiurn Date:
Mar. 28. 1986
Chemical
fibstract flnnual Uoiues (Vear 19 )
Seru i ce
Huraber
(CBS)* Ha«e
75-07-0 AceLsidehyde
107-13-1 Acrylonitrile
71-43-2 Benrene
56-23-5 Carbon Tetrachloride
67-66-3 Chloroform
1319-77-3 Cresols
95-50-1 o-DicWorobenzene
123-91-1 Dioxane
106-89-8 Epichlorohydrin
106-93-4 ELhylene Oibromide
107-06-2 Ettiylene Dtchloride
75-21-6 Ethylane Oxide
50-00-0 Formaldehyde
77-47-4 Hexacnlcrocyclopentadiene
71-55-6 Methyl Chloroform
75-OQ-2 Methylene Chloride
; 336-36-3 PCS's
127-J 8-4 Perchloroethylene
'08-95-2 Ptienols
75-36-9 Propyiene Oxide
r.O-S6-l Pyridine
100-42-5 SLyrene
105-38-3 Toluene
79-0 1 -6 Tnchloroethylene
76- 1 3- 1 1,1 ,2-Tnchloro- 1 .2,2-LrifIuoroethane
79-00-5 1 . 1 ,2-Trichloroethane
75-35-4 Vinylidene Chloride
133C-20-7 Xylenes
Used*
Rnount Units
Eaisa ions
Rmount Units
1
1 certify that the information given above is correct.
I certify that none of the above are used* (see cover letter).
Signature
Official Title
Date
Phone
State Form 20287
C3/03/36
SEH61-257
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U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, Illinois 60604
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