<>EPA
EPA Document# EPA-740-R1-7018
May 2018
United States	Office of Chemical Safety and
Environmental Protection Agency	Pollution Prevention
Problem Formulation of the Risk Evaluation for
Asbestos
May 2018

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TABLE OF CONTENTS
TABLE OF CONTENTS	2
ACKNOWLEDGEMENTS	5
ABBREVIATIONS	6
EXECUTIVE SUMMARY	8
1	INTRODUCTION	10
1.1	Regulatory History	11
1.2	Assessment History	12
1.3	Data and Information Collection	13
1.4	Data Screening during Problem Formulation	15
2	PROBLEM FORMULATION	15
2.1	Definition, Structure and Physical and Chemical Properties	15
2.1.1	Definition of Asbestos	15
2.1.2	Structure	16
2.1.3	Physical and Chemical Properties of Asbestos	16
2.2	Conditions of Use	18
2.2.1	Data and Information Sources	18
2.2.2	Identification of Conditions of Use	18
2.2.2.1	Categories Determined Not to be Conditions of Use During Problem Formulation	19
2.2.2.2	Categories of Conditions of Use Included in the Scope of Risk Evaluation	21
2.2.2.3	Overview of Conditions of Use and Life Cycle Diagram	22
2.3	Exposures	26
2.3.1	Fate and Transport	26
2.3.2	Releases to the Environment	27
2.3.3	Presence in the Environment and Biota	29
2.3.4	Environmental Exposures	29
2.3.5	Human Exposures	30
2.3.5.1	Occupational Exposures	30
2.3.5.2	Consumer Exposures	31
2.3.5.3	General Population Exposures	31
2.3.5.4	Potentially Exposed or Susceptible Subpopulations	32
2.4	Hazards (Effects)	33
2.4.1	Environmental Hazards	33
2.4.2	Human Health Hazards	34
2.4.2.1	Cancer Hazard	35
2.4.2.2	Potentially Exposed or Susceptible Subpopulations	36
2.5	Conceptual Models	36
2.5.1	Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposures
and Hazards	37
2.5.2	Conceptual Model for Consumer Activities and Uses: Potential Exposures and Hazards.... 39
2.5.3	Conceptual Model for Environmental Releases and Wastes: Potential Exposures and
Hazards	41
2.5.3.1 Pathways ThatEPA Expects to Include and Further Analyze in Risk Evaluation	41
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2.5.3.2 Pathways That EPA Expects to Include in Risk Evaluation but Not Further Analyze ..42
2.5.3.3 Pathways That EPA Does Not Expect to Include in the Risk Evaluation	42
2.6 Analysis Plan	47
2.6.1	Exposure	47
2.6.1.1	Environmental Fate and Environmental Releases	47
2.6.1.2	Environmental Exposures	48
2.6.1.3	Occupational Exposures	49
2.6.1.4	Consumer Exposures	50
2.6.2	Hazards (Effects)	51
2.6.2.1	Environmental Hazards	51
2.6.2.2	Human Health Hazards	51
2.6.3	Risk Characterization	52
REFERENCES	54
APPENDICES	58
Appendix A REGULATORY fflSTORY	58
A-l Federal Laws and Regulations	58
A-2 State Laws and Regulations	61
A-3 International Laws and Regulations	62
Appendix B PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE INFORMATION.... 63
B-l Process Information	63
B-1 -1 Manufacture and Import	63
B-1 -1 -1 Manufacturing	63
B-l-1-2 Import	63
B-l-2 Processing	63
B-1-2-1 Chlor-Alkali Industry	63
B-l-3 Uses	65
B-l-3-1 Oil Industry	65
B-l-3-2 Use of Sheet Gaskets in Titanium Dioxide Production	65
B-l-3-3 Commercial Uses	65
B-1-3-4 Consumer Uses	65
B-l-4 Disposal	66
B-2 Occupational Exposure Data	66
Appendix C SUPPORTING TABLE FOR INDUSTRIAL, COMMERCIAL AND CONSUMER
ACTIVITIES AND USES FOR CONCEPTUAL MODELS	68
Appendix D INCLUSION AND EXCLUSION CRITERIA FOR FULL TEXT SCREENING.... 71
D-1 Inclusion Criteria for Data Sources Reporting Environmental Fate Data	71
D-2 Inclusion Criteria for Data Sources Reporting Engineering and Occupational Exposure Data ..74
D-3 Inclusion Criteria for Data Sources Reporting Exposure Data on General Population,
Consumers and Ecological Receptors	76
D-4 Inclusion Criteria for Data Sources Reporting Human Health Hazards	79
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LIST OF TABLES
Table 1-1. Assessment History of Asbestos	12
Table 2-1. Physical and Chemical Properties of Asbestos Fiber Types a	16
Table 2-2. Categories Determined Not to be Conditions of Use During Problem Formulation	20
Table 2-3. Categories of Conditions of Use Included in the Scope of the Risk Evaluation	22
Table 2-4. Summary of Asbestos TRI Production-Related Waste Managed in 2015 (lbs)	27
Table 2-5. Summary of Asbestos TRI Releases to the Environment in 2015 (lbs)	28
Table 2-6. Total On-and Off-site Disposal or Other Releases of Friable Asbestos (lbs) (2009-2015),
based on TRI Data	28
Table 2-7. Ecological Hazard Characterization of Chrysotile Asbestos (C ASRN 12001-29-5)	34
LIST OF FIGURES
Figure 2-1. Asbestos Life Cycle Diagram	24
Figure 2-2. Asbestos Conceptual Model for Industrial and Commercial Activities and Uses: Potential
Exposures and Hazards	38
Figure 2-3. Asbestos Conceptual Model for Consumer Activities and Uses: Potential Exposures and
Hazards	40
Figure 2-4. Asbestos Conceptual Model for Environmental Releases and Wastes: Potential Exposures
and Hazards	46
LIST OF APPENDIX TABLES
TableApx B-1. Summary of Industry Sectors with Asbestos Personal Monitoring Air Samples
Obtained from OSHA Inspections Conducted Between 2011 and 2016	66
TableAppendix C-l. Preliminary Rationale for Inclusion and Exclusion of Exposure Pathways for
Industrial, Commercial and Consumer Activities	68
Table Apx D-l. Inclusion Criteria for Data Sources Reporting Environmental Fate Data	72
Table Apx D-2. Fate Endpoints and Associated Processes, Media and Exposure Pathways Considered in
the Development of the Environmental Fate Assessment	73
Table Apx D-3. Inclusion Criteria for Data Sources Reporting Engineering and Occupational Exposure
Data for Asbestos	74
Table Apx D-4. Engineering, Environmental Release and Occupational Data Necessary to Develop the
Environmental Release and Occupational Exposure Assessments	75
Table Apx D-5. Inclusion Criteria for Data Sources Reporting Asbestos Exposure Data on General
Population, Consumers and Ecological Receptors	78
Table Apx D-6. Inclusion Criteria for Data Sources Reporting Human Health Hazards Related to
Asbestos Exposure	79
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ACKNOWLEDGEMENTS
This report was developed by the United States Environmental Protection Agency (U.S. EPA), Office of
Chemical Safety and Pollution Prevention (OCSPP), Office of Pollution Prevention and Toxics (OPPT).
Acknowle dge me nts
The OPPT Assessment Team gratefully acknowledges participation and/or input from Intra-agency
reviewers that included multiple offices within EPA, Inter-agency reviewers that included multiple
Federal agencies, and assistance from EPA contractors GDIT (Contract No. CIO-SP3,
HHSN316201200013W), ERG (Contract No. EP-W-12-006), Versar (Contract No. EP-W-17-006), ICF
(Contract No. EPC14001) and SRC (Contract No. EP-W-12-003).
Docket
Supporting information can be found in public docket: EPA-HQ-QPPT-2016-0736.
Disclaimer
Reference herein to any specific commercial products, process or service by trade name, trademark,
manufacturer or otherwise does not constitute or imply its endorsement, recommendation or favoring by
the United States Government.
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ABBREVIATIONS
ABPO
1989 Asbestos Ban and Phase Out Rule
ACC
American Chemistry Council
ACGIH TLV
American Conference of Governmental Industrial Hygienists Threshold Limit Value
AHERA
Asbestos Hazard Emergency Response Act
ASHAA
Asbestos School Hazard Abatement Act
ASHARA
Asbestos School Hazard Abatement Reauthorization Act
ATSDR
Agency for Toxic Substances and Disease Registries
CAA
Clean Air Act
CASRN
Chemical Abstract Service Registry Number
CBI
Confidential Business Information
CDR
Chemical Data Reporting
CEPA
Canadian Environmental Protection Act
CERCLA
Comprehensive Environmental Response, Compensation and Liability Act
ChV
Chronic Value
coc
Concentration of Concern
CPCat
Chemical and Product Categories
CPID
Consumer Product Information Database
CPSC
Consumer Product Safety Commission
CWA
Clean Water Act
DHHS
Department of Health and Human Services
EG
Effluent Guideline
EMP
Elongated Mineral Particle
EPA
Environmental Protection Agency
EPCRA
Emergency Planning and Community Right-to-Know Act
EU
European Union
FDA
Food and Drug Administration
ffcc
Fibers per cubic centimeter
FHSA
Federal Hazardous Substance Act
g
Gram(s)
HEP A
High-Efficiency Particulate Air
HTS
Harmonized Tariff Schedule
IARC
International Agency for Research on Cancer
IgA
Immunoglobulin A
IgG
Immunoglobulin G
IRIS
Integrated Risk Information System
lb
Pound
LOEC
Lowest Observable Effect Concentration
MAP
Model Accreditation Plan
MCLG
Maximum Contaminant Level Goal
pm
Micrometers
MFL
Million Fibers per Liter
mg
Milligram(s)
MPa
Megapascal
MSDS
Material Safety Data Sheet
MSHA
Mine Safety and Health Administration
mV
Millivolt
NAICS
North American Industrial Classification System
ND
Non-detects (value is < analytical detection limit)
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NEI
National Emissions Inventory
NESHAP
National Emission Standard for Hazardous Air Pollutants
NIH
National Institutes of Health
NIOSH
National Institute for Occupational Safety and Health
NOEC
No Observable Effect Concentration
NOI
Notice of Intent
NPL
National Priorities List
NTP
National Toxicology Program
OCSPP
Office of Chemical Safety and Pollution Prevention
OECD
Organisation for Economic Co-operation and Development
ONU
Occupational Non-User
OPPT
Office of Pollution Prevention and Toxics
OSHA
Occupational Safety and Health Administration
PBPK
Physiologically Based Pharmacokinetic
PECO
Population, Exposure, Comparator and Outcome
PEL
Permissible Exposure Level
PESO
Pathways/Processes, Exposure, Setting and Outcomes
POD
Point of Departure
POTW
Publicly Owned Treatment Works
PPE
Personal Protective Equipment
ppm
Part(s) per Million
RCRA
Resource Conservation and Recovery Act
PV
Production Volume
QSAR
Quantitative Structure Activity Relationship
RA
Risk Assessment
RESO
Receptors, Exposure, Setting/Scenario and Outcomes
RfC
Reference Concentration
RIA
Regulatory Impact Analysis
SDS
Safety Data Sheet
SDWA
Safe Drinking Water Act
TCCR
Transparent, Clear, Consistent, and Reasonable
TRI
Toxics Release Inventory
TSCA
Toxic Substances Control Act
TURA
Toxics Use Reduction Act
TWA
Time Weighted Average
UCMR3
Unregulated Contaminant Monitoring Rule 3
U.S.
United States
USGS
United States Geological Survey
WHO
World Health Organization
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EXECUTIVE SUMMARY
TSCA § 6(b)(4) requires the U.S. Environmental Protection Agency (EPA) to establish a risk evaluation
process. In performing risk evaluations for existing chemicals, EPA is directed to "determine whether a
chemical substance presents an unreasonable risk of injury to health or the environment, without
consideration of costs or other non-risk factors, including an unreasonable risk to a potentially exposed
or susceptible subpopulation identified as relevant to the risk evaluation by the Administrator under the
conditions of use." In December of 2016, EPA published a list of 10 chemical substances that are the
subject of the Agency's initial chemical risk evaluations (81 FR 91927), as required by TSCA §
6(b)(2)(A). Asbestos was one of these chemicals.
TSCA § 6(b)(4)(D) requires that EPA publish the scope of the risk evaluation to be conducted, including
the hazards, exposures, conditions of use and potentially exposed or susceptible subpopulations that the
Administrator expects to consider and in June 2017, EPA published the Scope of the Risk Evaluation for
Asbestos. As explained in the scope document, because there was insufficient time for EPA to provide
an opportunity for comment on a draft of the scope, as EPA intends to do for future scope documents,
EPA is publishing and taking public comment on a problem formulation document to refine the current
scope, as an additional interim step prior to publication of the draft risk evaluation for asbestos.
Comments received on this problem formulation document will inform development of the draft risk
evaluation.
This problem formulation document refines the conditions of use, exposures and hazards presented in
the scope of the risk evaluation for asbestos and presents refined conceptual models and analysis plans
that describe how EPA expects to evaluate the risk for asbestos.
For the purposes of scoping, problem formulation and risk evaluation, EPA has adopted the definition of
asbestos as defined by TSCA Title II (added to TSCA in 1986), Section 202 as the "asbestiform varieties
of six fiber types - chrysotile (serpentine), crocidolite (riebeckite), amosite (cummingtonite-grunerite),
anthophyllite, tremolite or actinolite." The latter five fiber types are amphibole varieties. The general
CAS Registry Number (CASRN) of asbestos is 1332-21-4; this is the only asbestos CASRN on the
TSCA Inventory. However, other CASRNs are available for specific fiber types.
Asbestos has not been mined or otherwise produced in the United States since 2002; therefore, any new
asbestos entering this country is imported. In 2017, the United States imported approximately 300 metric
tons of raw asbestos, all of it comprised of chrysotile asbestos.
EPA has identified the ongoing use of chrysotile asbestos in: industrial processes in the chlor-alkali
industry, asbestos sheet gaskets for use in equipment used in the manufacture of titanium dioxide and
asbestos brake blocks in oilfield equipment and aftermarket asbestos brake linings. In addition, certain
asbestos containing products can be imported into the U.S., but the amounts are not known. These
products are mostly used in industrial processes (e.g. cement products) but could also be used by
consumers, and include woven products and automotive brakes and linings.
In the case of asbestos, legacy uses, associated disposals, and legacy disposals will be excluded from the
problem formulation and risk evaluation, as they were in the Scope document. These include asbestos-
containing materials that remain in older buildings or are part of older products but for which
manufacture, processing and distribution in commerce are not currently intended, known or reasonably
foreseen. EPA is excluding these activities because EPA generally interprets the mandates under section
TSCA § 6(a)-(b) to conduct risk evaluations and any corresponding risk management to focus on uses
for which manufacture, processing or distribution is intended, known to be occurring, or reasonably
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foreseen, rather than reaching back to evaluate the risks associated with legacy uses, associated disposal,
and legacy disposal, and interprets the definition of conditions of use in that context.
During scoping and problem formulation EPA reviewed the existing EPA IRIS health assessments to
ascertain the established health hazards and any known toxicity values. EPA had previously, in the IRIS
assessments, identified asbestos as a carcinogen causing both lung cancer and mesothelioma from
inhalation exposures and derived a unit risk to address both cancers. No toxicity values or unit risks have
yet been estimated for other cancers that have been identified by the International Agency for Research
on Cancer (IARC) and others. Given the well-established carcinogenicity of asbestos for lung cancer
and mesothelioma, EPA has decided to limit the scope of its systematic review to these two specific
cancers with the goal of updating, or reaffirming, the existing unit risk. No clear association was found
for drinking water asbestos exposure and cancer. Dermal exposures may cause non-cancerous skin
lesions. Since neither oral nor dermal exposures are expected to contribute to the risks of lung cancer
and mesothelioma, which are the basis of the 1988 cancer unit risk, exposures from the oral and dermal
routes will not be assessed. These inhalation hazards will be evaluated based on the specific exposure
scenarios identified for workers, consumers and the general population where applicable.
Most of the ongoing uses of asbestos pertain to industrial and commercial uses. Exposures to workers,
consumers and the general population, as well as environmental receptors may occur from industrial
releases and use of asbestos-containing products. Only environmental releases of friable asbestos are
reported in the Toxics Release Inventory. Asbestos fibers are largely chemically inert under
environmental conditions. They may undergo minor physical changes, such as changes in fiber length,
but do not degrade, react, or dissolve to any appreciable extent in the environment.
The revised conceptual models presented in this problem formulation identify conditions of use;
exposure pathways (e.g., media); exposure routes (inhalation); potentially exposed or susceptible
subpopulations; and hazards EPA expects to consider in the risk evaluation. The initial conceptual
models provided in the scope document were revised during problem formulation based on evaluation of
reasonably available information for physical and chemical properties, fate, exposures, hazards, and
conditions of use and based upon consideration of other statutory and regulatory authorities.
EPA's overall objectives in the risk evaluation process are to conduct timely, relevant, high-quality, and
scientifically credible risk evaluations within the statutory deadlines, and to evaluate the conditions of
use that raise greatest potential for risk 1 « *1 5, J ='8 (July 20, 2017).
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1 INTRODUCTION
This document presents for comment the problem formulation of the risk evaluation to be conducted for
asbestos under the Frank R. Lautenberg Chemical Safety for the 21st Century Act. The Frank R.
Lautenberg Chemical Safety for the 21st Century Act amended the Toxic Substances Control Act
(TSCA), the Nation's primary chemicals management law, on June 22, 2016. The new law includes
statutory requirements and deadlines for actions related to conducting risk evaluations of existing
chemicals.
In December of 2016, EPA published a list of 10 chemical substances that are the subject of the
Agency's initial chemical risk evaluations (	), as required by TSCA § 6(b)(2)(A). These 10
chemical substances were drawn from the 2014 update of EPA's TSCA Work Plan for Chemical
Assessments, a list of chemicals that EPA identified in 2012 and updated in 2014 (currently totaling 90
chemicals) for further assessment under TSCA. EPA's designation of the first 10 chemical substances
constituted the initiation of the risk evaluation process for each of these chemical substances, pursuant to
the requirements of TSCA § 6(b)(4).
TSCA § 6(b)(4)(D) requires that EPA publish the scope of the risk evaluation to be conducted, including
the hazards, exposures, conditions of use and potentially exposed or susceptible subpopulations that the
Administrator expects to consider, within 6 months after the initiation of a risk evaluation. The scope
documents for all first 10 chemical substances were issued on June 22, 2017. The first 10 Problem
Formulation documents are a refinement of what was presented in the first 10 scope documents. TSCA §
6(b)(4)(D) does not distinguish between scoping and problem formulation, and requires EPA to issue
scope documents that include information about the chemical substance, including the hazards,
exposures, conditions of use, and the potentially exposed or susceptible subpopulations that the
Administrator expects to consider in the risk evaluation. In the future, EPA expects scoping and problem
formulation to be completed prior to the issuance of scope documents and intends to issue scope
documents that include problem formulation.
As explained in the scope document, because there was insufficient time for EPA to provide an
opportunity for comment on a draft of the scope, as EPA intends to do for future scope documents, EPA
is publishing and taking public comment on a problem formulation document to refine the current scope,
as an additional interim step prior to publication of the draft risk evaluation for asbestos. Comments
received on this problem formulation document will inform development of the draft risk evaluation.
The Agency defines problem formulation as the analytical phase of the risk assessment in which "the
purpose of the assessment is articulated, the problem is defined, and a plan for analyzing and
characterizing risk is determined" [see Section 2.2 of the Framework for Human Health Risk Assessment
to Inform Decision Making, (	1014a)]. The outcome of problem formulation is a conceptual
model(s) and an analysis plan. The conceptual model describes the linkages between stressors and
adverse human health and environmental effects, including the stressors), exposure pathway(s),
exposed life stage(s) and populations), and endpoint(s) that will be addressed in the risk evaluation
(U.S. EPA, 2014a). The analysis plan follows the development of the conceptual model(s) and is
intended to describe the approach for conducting the risk evaluation, including its design, methods and
key inputs and intended outputs as described in the EPA Human Health Risk Assessment Framework
(	2014a). The problem formulation documents refine the initial conceptual models and
analysis plans that were provided in the scope documents.
First, EPA has removed from the risk evaluation any activities and exposure pathways and hazards that
EPA has concluded do not warrant inclusion in the risk evaluation. For example, for some activities that
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were listed as "conditions of use" in the scope document, EPA has insufficient information following the
further investigations during problem formulation to find they are circumstances under which the
chemical is actually "intended, known, or reasonably foreseen to be manufactured, processed,
distributed in commerce, used, or disposed of"
Second, EPA also identified certain exposure pathways that are under the jurisdiction of regulatory
programs and associated analytical processes carried out under other EPA-administered environmental
statutes - namely, the Clean Air Act (CAA), the Safe Drinking Water Act (SDWA), the Clean Water
Act (CWA), and the Resource Conservation and Recovery Act (RCRA) - and which EPA does not
expect to include in the risk evaluation.
As a general matter, EPA believes that certain programs under other Federal environmental laws
adequately assess and effectively manage the risks for the covered exposure pathways. To use Agency
resources efficiently under the TSCA program, to avoid duplicating efforts taken pursuant to other
Agency programs, to maximize scientific and analytical efforts, and to meet the three-year statutory
deadline, EPA is planning to exercise its discretion under TSCA 6(b)(4)(D) to focus its analytical efforts
on exposures that are likely to present the greatest concern and consequently merit a risk evaluation
under TSCA, by excluding, on a case-by-case basis, certain exposure pathways that fall under the
jurisdiction of other EPA-administered statutes.1 EPA does not expect to include any such excluded
pathways as further explained below in the problem formulation. The provisions of various EPA-
administered environmental statutes and their implementing regulations represent the judgment of
Congress and the Administrator, respectively, as to the degree of health and environmental risk
reduction that is sufficient under the various environmental statutes.
Third, EPA identified any conditions of use, hazards, or exposure pathways which were included in the
scope document and that EPA expects to include in the risk evaluation but which EPA does not expect
to further analyze in the risk evaluation. EPA expects to be able to reach conclusions about particular
conditions of use, hazards or exposure pathways without further analysis and therefore plans to conduct
no further analysis on those conditions of use, hazards or exposure pathways in order to focus the
Agency's resources on more extensive or quantitative analyses. Each risk evaluation will be "fit-for-
purpose," meaning not all conditions of use will warrant the same level of evaluation and the Agency
may be able to reach some conclusions without comprehensive or quantitative risk evaluations. 82 FR
33726, 33734, 33739 (My 20, 2017).
EPA received comments on the published scope document for asbestos and has considered the
comments specific to asbestos in this problem formulation document. EPA is soliciting public comment
on this problem formulation document and when the draft risk evaluation is issued the Agency intends to
respond to comments that are submitted. In its draft risk evaluation, EPA may revise the conclusions and
approaches contained in this problem formulation, including the conditions of use and pathways covered
and the conceptual models and analysis plans, based on comments received.
1.1 Regulatory History
EPA conducted a search of existing domestic and international laws, regulations and assessments
pertaining to asbestos. EPA compiled this summary from data available from federal, state, international
and other government sources, as cited in Appendix A. EPA evaluated and considered the impact of at
1 As explained in the final rule for chemical risk evaluation procedures, "EPA may, on a case-by case basis, exclude certain
activities that EPA has determined to be conditions of use in order to focus its analytical efforts on those exposures that are
likely to present the greatest concern, and consequently merit an unreasonable risk determination [82FR 33726, 33729] (July
20, 2017).
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least some of these existing laws and regulations in the problem formulation step to determine what, if
any further analysis might be necessary as part of the risk evaluation. Consideration of the nexus
between these existing regulations and TSCA conditions of use may additionally be made as
detailed/specific conditions of use and exposure scenarios are developed in conducting the analysis
phase of the risk evaluation.
Federal Laws and Regulations
Asbestos is subject to federal statutes or regulations, other than TSCA, that are implemented by other
offices within EPA and/or other federal agencies/departments. A summary of federal laws, regulations
and implementing authorities is provided in Appendix A-l; including adding the Department of
Transportation regulations on asbestos since the scope document.
State Laws and Regulations
Asbestos is subject to statutes or regulations implemented by state agencies or departments. A summary
of state laws, regulations and implementing authorities is provided in Appendix A-2 (updated since the
scope document).
Laws and Regulations in Other Countries and International Treaties or Agreements
Asbestos is subject to statutes or regulations in countries other than the United States and/or
international treaties and/or agreements. A summary of these laws, regulations, treaties and/or
agreements is provided in Appendix A-3.
1.2 Assessment History
EPA nas identified assessments conducted by other EPA Programs and other organizations (see Table
1-1). Depending on the source, these assessments may include information on conditions of use,
hazards, exposures and potentially exposed or susceptible subpopulations—information useful to EPA in
preparing the scope and problem formulation documents for the risk evaluation. Table 1-1 shows the
assessments that have been conducted. Since publication of the Scope document in June 2017 EPA has
added documents to Table 1-1 that supported the 1988 Asbestos Ban and Phase Out rule (54 FR 29460)
which were consulted for background information on uses, exposures, and risk assessment, as well as
the ecological risk assessment conducted attheLibby Asbestos Superlund Site.
In addition to using this information, EPA intends to conduct a full review of the relevant
data/information collected in the initial comprehensive search (see Asbestos (CASRN 1332-21-4)
Bibliography: Supplemental File for the TSCA Scope Document,	)-QPPT-2016-0?36) following
the literature search and screening strategies documented mihQ Strategy for Conducting Literature
Searches for Asbestos: Supplemental File for the TSCA Scope Document, EP A-H.Q-QPPT-2016-0736).
This will ensure that EPA considers data/information that has been made available since these
assessments were conducted.
Table 1-1. Assessment History of Asbestos
Authoring Organization
Assessment
EPA assessments
EPA, Integrated Risk Information System (IRIS)
IRIS on Ashcnus (lCiSSh)
EPA, Integrated Risk Information System (IRIS)
lklv V .^ssiinit on i \iic4tiholc \sbestos
G^Iii )
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A ill ho ri n« ()i"iiii ni/a lion
Assessment
LP A, Region S
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risk evaluation. Additional information that may be considered and was not part of the initial
comprehensive bibliographies will be documented in the Draft Risk Evaluation for asbestos.
Data Collection: Data Search
EPA/OPPT conducted chemical-specific searches for data and information on: physical and chemical
properties; environmental fate and transport; conditions of use information; environmental and human
exposures, including potentially exposed or susceptible subpopulations; and, ecological and human
health hazard, including potentially exposed or susceptible subpopulations.
EPA/OPPT designed its initial data search to be broad enough to capture a comprehensive set of sources
containing data and/or information potentially relevant to the risk evaluation. For most disciplines, the
search was not limited by date and was conducted on a wide range of data sources, including but not
limited to: peer-reviewed literature and gray literature (e.g., publicly-available industry reports, trade
association resources, government reports). When available, EPA/OPPT relied on the search strategies
from recent assessments, such as EPA Integrated Risk Information System (IRIS) assessments and the
National Toxicology Program's (NTP) Report on Carcinogens, to identify relevant references and
supplemented these searches to identify relevant information published after the end date of the previous
search to capture more recent literature. Strategy for Conducting Literature Searches for Asbestos:
Supplemental File for the TSCA Scope Document (EP A-HQ-QPPT-2016-0736) provides details about
the data sources and search terms that were used in the initial search.
Data Collection: Data Screening
Following the data search, references were screened and categorized using selection criteria outlined in
Strategy for Conducting Literature Searches for Asbestos: Supplemental File for the TSCA Scope
Document (	Q-QPPT-2016-0736). Titles and abstracts were screened against the criteria as a first
step with the goal of identifying a smaller subset of the relevant data to move into the subsequent data
extraction and data evaluation steps. Prior to full-text review, EPA/OPPT anticipates refinements to the
screening strategies, as informed by an evaluation of the performance of the initial title/abstract
screening and categorization process.
The categorization scheme (or tagging structure) used for data screening varies by scientific discipline
(i.e., physical and chemical properties; environmental fate and transport; chemical use/conditions of use
information; human and environmental exposures, including potentially exposed or susceptible
subpopulations identified by virtue of greater exposure; human health hazard, including potentially
exposed or susceptible subpopulations identified by virtue of greater susceptibility; and ecological
hazard). However, within each data set, there are two broad categories or data tags: (1) on-topic
references or (2) off-topic references. On-topic references are those that may contain data and/or
information relevant to the risk evaluation. Off-topic references are those that do not appear to contain
data or information relevant to the risk evaluation. The Strategy for Conducting Literature Searches for
Asbestos: Supplemental File for the TSCA Scope Document (EP A-HQ - OF'" ^ 0736) discusses the
inclusion and exclusion criteria that EPA/OPPT used to categorize references as on-topic or off-topic.
Additional data screening using sub-categories (or sub-tags) was also performed to facilitate further
sorting of data/information. For example, identifying references by source type (e.g., published peer-
reviewed journal article, government report); data type (e.g., primary data, review article); human health
hazard (e.g., liver toxicity, cancer, reproductive toxicity); or chemical-specific and use-specific data or
information. These sub-categories are described in the Strategy for Conducting Literature Searches for
Asbestos: Supplemental File for the TSCA Scope Document (EP A-HQ-QPPT-2016-0736) and will be
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used to organize the different streams of data during the stages of data evaluation and data integration
steps of systematic review.
Results of the initial search and categorization results can be found in the Asbestos (CASRN1332-21-4)
Bibliography: Supplemental File for the TSCA Scope Document (U \ MQ-QPPT-2016-0736). The
scope document provided a comprehensive list (bibliography) of the sources of data identified by the
initial search and the initial categorization for on-topic and off-topic references. Because systematic
review is an iterative process, EPA/OPPT expects that some references may move from the on-topic to
the off-topic categories, and vice versa. Moreover, targeted supplemental searches may also be
conducted to address specific needs for the analysis phase (e.g., to locate specific data needed for
modeling); hence, additional on-topic references not initially identified in the initial search may be
identified as the systematic review process proceeds.
1.4 Data Screening during Problem Formulation
EPA/OPPT is in the process of completing the full text screening of the on-topic references identified in
the Asbestos (CASRN: 1332-21-4) Bibliography: Supplemental File for the TSCA Scope Document
(EPA-HQ-QPPT-2016-0736). The screening process at the full-text level is described in the Application
of Systematic Review in TSCA Risk Evaluations document (	18). Appendix D provides the
inclusion and exclusion criteria applied at the full text screening. The eligibility criteria are guided by
the analytical considerations in the revised conceptual models and analysis plan, as discussed in the
problem formulation document. Thus, it is expected the number of data/information sources entering
evaluation is reduced to those that are relevant to address the technical approach and issues described in
the analysis plan of this document.
Following the screening process, the quality of the included studies will be assessed using the evaluation
strategies that are described in the Application of Systematic Review in TSCA Risk Evaluations (U.S.
EPA, 2018).
2 PROBLEM FORMULATION
As required by TSCA, the scope of the risk evaluation identifies the conditions of use, hazards,
exposures and potentially exposed or susceptible subpopulations that the Administrator expects to
consider. To communicate and visually convey the relationships between these components, EPA
included in the scope document a life cycle diagram and conceptual models that describe the actual or
potential relationships between asbestos and human and ecological receptors. During the problem
formulation, EPA revised the conceptual models based on further data gathering and analysis, as
presented in this problem formulation document. An updated analysis plan is also included which
identifies, to the extent feasible, the approaches and methods that EPA may use to assess exposures,
effects (hazards) and risks under the conditions of use of asbestos.
2.1 Definition, Structure and Physical and Chemical Properties
2.1.1 Definition of Asbestos
Asbestos is a "generic commercial designation for a group of naturally occurring mineral silicate fibers
of the serpentine and amphibole series" (IARC, 2012). The Chemical Abstract Service (CAS) definition
of asbestos is "a grayish, non-combustible fibrous material. It consists primarily of impure magnesium
silicate minerals." The general CAS Registry Number (CASRN) of asbestos is 1332-21-4; this is the
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only asbestos CASRN on the TSCA Inventory. However, other CASRNs are available for specific fiber
types.
TSC A Title II (added to TSC A in 1986), Section 202 defines asbestos as the "asbestiform varieties of six
fiber types - chrysotile (serpentine), crocidolite (riebeckite), amosite (cummingtonite-grunerite),
anthophyllite, tremolite or actinolite." The latter five fiber types are amphibole varieties. EPA is using
this definition of asbestos for the risk evaluation for asbestos. EPA received public comment on the
definition and fiber types of asbestos used in the Scope document and adjusted Table 2-1 to clarify the
fiber types and size included in the definition. EPA will continue to use the TSCA Title II definition of
asbestos in the risk evaluation.
The most common form of asbestos used in the United States is chrysotile, which is found in serpentine
rock formations (chrysotile content average 5%, with a maximum 50%) (WHO, 2014). Chrysotile was
the predominant type of asbestos used in the United States and is currently the only type of raw asbestos
imported. The United States Geological Survey (USGS) estimated that 300 metric tons of asbestos were
imported into the U.S. in 2017, 57% less than 702 metric tons in 2016, and 22% less than 386 metric
tons in 2015 (USGS, 2018). It is used wholly by the chlor-alkali industry.
The three varieties of amphibole fibers that are the most commonly found are crocidolite, amosite and
tremolite. Crocidolite and amosite were the only amphiboles with significant industrial uses in recent
years. Tremolite, although having essentially no industrial application, may be found as a contaminant
associated with other fibers or in other industrial minerals (e.g., chrysotile and talc) (Virta, ).
2.1.2 Structure
As with all silicate minerals, the basic building blocks of asbestos fibers are silicate tetrahedra [SiCU]4"
where four oxygen atoms are covalently bound to the central silicon. These tetrahedrons occur as sheets
[Si40io] in chrysotile (U.S. EPA, 2014a). In the case of chrysotile, an octahedral brucite layer having
the formula [Mg604(0H)8] is intercalated between each silicate tetrahedral sheet.
2.1.3 Physical and Chemical Properties of Asbestos
Physical-chemical properties influence the environmental behavior and the toxic properties of a
chemical, thereby informing the potential conditions of use, exposure pathways and routes, and hazards
EPA intends to consider. For scope development, EPA considered the measured or estimated physical-
chemical properties set forth in Table 2-1.
Asbestos fibers are basically chemically inert, and they do not evaporate, dissolve, burn or undergo
significant reactions with most chemicals. They are insoluble in water and organic solvents. In acid and
neutral aqueous media, magnesium is lost from the outer brucite layer of chrysotile. Amphibole fibers
are more resistant to acid attack and all varieties of asbestos are resistant to attack by alkalis (Virta,
Table 2-1. Physical and Chemical Properties of Asbestos Fiber Types a

( lirxsoiilo
Amosilo
( lociiloliio
Aslvslilonn
Ti'omoliio
Aslvslilonn
Anlho|ih\ llilo
Aslvslilonn
Aclinoluo
lissonlKil
composition
Nig siliailo
with some
water
l o, \\u
silicate with
some water
\n; 1 o
silicate with
some water
("a, Mg
silicate with
some water
Nig siliailo
with some iron
("a, Mg, 1 o
silicate with
some water
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( hi\soiilo
Amosile
( I'ocidolilo
Aslvslilomi
Tivmoluo
Aslvslilomi
Anlho|ili\ Nile
Aslvslilomi
Aclinoliie
Color
Usually white
to grayish
green; may
have tan
coloration
Yellowish
gray to dark
brown
Cobalt blue
to lavender
blue
Gray-white,
green, yellow,
blue
Grayish white,
also brown-
gray or green
Greenish
Luster
Silky
Vitreous to
pearly
Silky to dull
Silky
Vitreous to
pearly
Silky
Surface areab-c
(m2/g)
13-18
2-9
2-9
2-9
2-9
2-9
Hardness (Mohs)
2.5-4.0
5.5-6.0
4.0
5.5
5.5-6.0
6.0
Specific gravity
2.4-2.6
3.1-3.25
3.2-3.3
2.9-3.2
2.85-3.1
3.0-3.2
Optical
properties
Biaxial
positive
parallel
extinction
Biaxial
positive
parallel
extinction
Biaxial
oblique
extinction
Biaxial
negative
oblique
extinction
Biaxial positive
extinction
parallel
Biaxial
negative
extinction
inclined
Refractive index
1.53-1.56
1.63-1.73
1.65-1.72
1.60- 1.64
1.61
1.63 weakly
pleochroic
Flexibility
High
Fair
Fair to good
Poor,
generally
brittle
Poor
Poor
Texture
Silky, soft to
harsh
Coarse but
somewhat
pliable
Soft to harsh
Generally
harsh
Harsh
Harsh
Spinnability
Very good
Fair
Fair
Poor
Poor
Poor
Tensile strength
(MP a)
1,100-4,400
1,500-2,600
1,400-4,600
<500
<27
<7
Fiber size,
median true
diameter (|_im)d
0.06
0.26
0.09
No data
No data
No data
Fiber size,
median true
length (|_im)d
0.55
2.53
1.16
No data
No data
No data
Resistance to:
Acids
Weak,
undergoes
fairly rapid
attack
Fair, slowly
attacked
Good
Good
Very good
Fair
Bases
Very good
Good
Good
Good
Very good
Fair
Zeta potential
(mV)
+13.6 to +54
-20 to -40
-32
NA
NA
NA
Decomposition
temperature (°C)
600-850
600-900
400-900
950-1,040
950
NA
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Aslvslilomi
Aslvslilomi
Aslvslilomi

( luxsolilo
Amosilo
( locklolilo
Tivmoliio
Anlho|ih\ llilo
Aclinoliio
aBadollet (1951).




b Hodgson (1986).




c Addison etal. (1966).



d Hwang (1983)




2.2 Conditions of Use
TSCA § 3(4) defines the conditions of use as "the circumstances, as determined by the Administrator,
under which a chemical substance is intended, known, or reasonably foreseen to be manufactured,
processed, distributed in commerce, used, or disposed of"
2.2.1	Data and Information Sources
In the scope documents EPA identified, based on reasonably available information, the conditions of use
for the subject chemical. As further described in this document, EPA searched a number of available
data sources (e.g., Use and Market Profile for Asbestos, EPA-I	'736-0085). Based on
this search, EPA published a preliminary list of information and sources related to chemical conditions
of use (see P stm. < '•»/>" w,o't on Manufacturing, Processing, Distribution, Use, and Disposal:
Asbestos) (Docket:	) (	), prior to a February 2017
public meeting on scoping efforts for risk evaluation convened to solicit comment and input from the
public. EPA also convened meetings with companies, industry groups, chemical users and other
stakeholders to aid in identifying and verifying conditions of use. The information and input received
from the public and stakeholder meetings was incorporated into this document to the extent appropriate,
as indicated in Table 2-2. Thus, EPA believes the identified manufacture, processing, distribution, use
and disposal activities identified in this document constitute the intended, known, and reasonably
foreseen activities associated with the subject chemical, based on reasonably available information.
2.2.2	Identification of Conditions of Use
To determine the current conditions of use of asbestos and inversely, activities that do not qualify as
conditions of use, EPA conducted extensive research and outreach. This included EPA's review of
published literature and online databases including the most recent data available from EPA's Chemical
Data Reporting program (CDR), Safety Data Sheets (SDSs), the United States Geological Survey's
Mineral Commodities Summary and Minerals Yearbook, the U.S. International Trade Commission's
Dataweb and government and commercial trade databases. EPA also reviewed company websites of
potential manufacturers, importers, distributors, retailers, or other users of asbestos. EPA also received
comments on the Scope of the Risk Evaluation for Asbestos (EPA-HQ-QPPT-2016-0736-0086) that
were used to determine the conditions of use. In addition, prior to the June 2017 publication of the scope
document, EPA convened meetings with companies, industry groups, chemical users, and other
stakeholders to aid in identifying conditions of use and verifying conditions of use identified by EPA.
The Scope document (	Q-QPPT-2016-0736-0086) identified uses of asbestos and described them
in terms of product categories. In an effort to understand the current asbestos product market, EPA
referred to the Regulatory Impact Analysis [RIA] of Controls on Asbestos and Asbestos Products (Final
Report Volume III), which was conducted in support of the 1989 Asbestos: Manufacture, Importation,
Processing, and Distribution in Commerce Prohibitions; Final Rule (40 CFR Pa ). The RIA
explained that in 1981, asbestos products were distributed into 35 product categories ( ,S. EPA, 1989).
For scoping, EPA researched the 35 product categories included in the 1989 RIA, and based on the
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results of this research, developed the following use categories that reflect current knowledge of uses as
of June 2017 when the Scope document was published:
•	Known Use - companies and manufacturing processes are identified
•	Evidence of Use - web sites and/or Safety Data Sheets (SDS) indicate asbestos in products
•	Reasonably Foreseen Use - indication by USGS that asbestos-containing products are
imported to the United States
EPA has removed from the risk evaluation any activities that EPA has concluded do not constitute
conditions of use - for example, because EPA has insufficient information to find certain activities are
circumstances under which the chemical is actually "intended, known, or reasonably foreseen to be
manufactured, processed, distributed in commerce, used or disposed of" EPA has also identified any
conditions of use that EPA does not expect to include in the risk evaluation. As explained in the final
rule for Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act,
TSCA section 6(b)(4)(D) requires EPA to identify "the hazards, exposures, conditions of use and the
potentially exposed or susceptible subpopulations that the Agency expects to consider in a risk
evaluation," suggesting that EPA may exclude certain activities that EPA has determined to be
conditions of use on a case-by-case basis (82 FR 33736, 33729; July 20, 2017). For example, EPA may
exclude conditions of use that the Agency has sufficient basis to conclude would present only de
minimis exposures or otherwise insignificant risks (such as use in a closed system that effectively
precludes exposure or use as an intermediate).
The activities that EPA no longer believes are conditions of use or that were otherwise excluded during
problem formulation are described in Section 2.2.2.1. The conditions of use included in the scope of the
risk evaluation are summarized in Section 2.2.2.2.
2.2.2.1 Categories Determined Not to be Conditions of Use During Problem
Formulation
During problem formulation, the conditions of use of asbestos identified in the Scope document were
further refined upon determination that EPA has insufficient information to find certain activities to be
"conditions of use." After further investigation of the current conditions of use - circumstances under
which the chemical is "intended, known, or reasonably foreseen to be manufactured, processed,
distributed in commerce, used, or disposed of' - EPA determined there is a lack of sufficient evidence
of the import, processing, or distribution of asbestos in adhesives and sealants, roof and non-roof
coatings, and building materials other than asbestos cement products. EPA had originally identified an
asbestos-containing adhesive for use as a mirror adhesive but later determined after contacting the
supplier that it is no longer sold. EPA also identified during the scoping process a domestic company
that appeared to manufacture and sell asbestos-containing roof and non-roof coatings, but after
contacting the company, determined that the information available on their website was outdated and
those products were no longer manufactured and sold in the United States.
Based on data available to EPA, general and some specified building materials and other unspecified
activities have been removed from consideration from the original scope during problem formulation, as
depicted in Table 2-2. EPA does not expect to consider or evaluate any such products or associated
hazards or exposures in the applicable risk evaluation because the use of asbestos in these products is
not intended, known, or reasonably foreseen in the United States. Therefore, the asbestos-containing
products listed in Table 2-2 are not included in the Life Cycle Diagram, Figure 2-1.
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Table 2-2. Categories Determined Not to be Conditions of Use During Problem Formulation
Activity
Product Category
Kxamplc
No Known, Intended,
or Reasonably
Foreseen Use
Adhesives and Sealants
Mirror adhesive
Roof and Non-Roof Coatings
Roofs/Foundations; Mastics
Building Materials, Other
Articles not specified, including
building materials other than asbestos
cement products
Legacy Use — Excludedfrom Scope (and Problem Formulation) of the Risk Evaluation
EPA interprets the mandates under section 6(a)-(b) to conduct risk evaluations and any corresponding
risk management to focus on current and prospective uses for which manufacture, processing, or
distribution in commerce is intended, known or reasonably foreseen, rather than reaching back to
evaluate the risks associated with legacy uses, associated disposal, and legacy disposal, and interprets
the definition of "conditions of use" in that context (TSCA section 6(b)(4)(B)). In other words, EPA
interprets the risk evaluation process of section 6 to focus on the continuing flow of chemical substances
from manufacture, processing and distribution in commerce into the use and disposal stages of their life
cycle. Consistent with this rationale, EPA has excluded certain uses from the scope of the risk
evaluation, as identified below.
During scoping, EPA identified uses including pre-existing materials currently in place within buildings
(e.g., insulation materials, flooring, etc.) and also within pre-existing non-building equipment. Many
asbestos products fall into this category. These materials were installed in the past, and there is no
evidence to suggest that manufacturing, processing, or distribution for such activities is intended,
known, or reasonably foreseen; EPA received no public comments providing information to indicate
otherwise. Legacy asbestos-containing products excluded from the scope of the risk evaluation include:
•	Asbestos arc chutes
•	Asbestos pipeline wrap
•	Asbestos separators in fuel cells and batteries
•	Asbestos-reinforced plastics
•	Beater-add gaskets
•	Extruded sealant tape
•	Filler for acetylene cylinders
•	High-grade electrical paper
•	Millboard
•	Missile liner
•	Roofing felt
•	Vinyl-asbestos floor tile
Upon further investigation during problem formulation, EPA has determined that seven asbestos product
categories (asbestos packings, asbestos protective clothing, automatic transmission friction components,
clutch facings, asbestos-cement flat sheet, asbestos-cement shingles, and corrugated asbestos-cement
sheet) that were listed as legacy uses in the Scope document fall under broader categories that EPA has
identified as conditions of use (other gaskets and packing, woven products, automotive friction materials
and asbestos cement products). Therefore, EPA has removed these seven product categories from the
above list because it is reasonably foreseen that these products could be considered under the risk
evaluation as specific products in broader categories of conditions of use.
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The manufacture, processing, and distribution for a number of additional uses of asbestos were banned
under TSCA in 1989 as part of the Asbestos: Manufacture, Importation, Processing, and Distribution in
Commerce Prohibitions; Final Rule (40 CFRPart 763) (also known as Asbestos Ban and Phase-out
Rule (Remanded), 1989). The uses of asbestos covered by the ban and thus excluded from the scope of
the risk evaluation include:
•	Corrugated paper
•	Rollboard
•	Commercial paper
•	Specialty paper
•	Flooring felt
•	New uses2
Another legacy use not included in the scope of this evaluation is Libby Amphibole asbestos, which is a
mixture of several mineral fibers such as winchite, richterite, and tremolite found in vermiculite ore
mined near Libby, MT and extensively distributed throughout the United States during the 20th century.
Vermiculite from Libby, MT had a range of commercial applications, the most common of which
included packing material, attic and wall insulation, various garden and agricultural products, and
various cement and building products. Although vermiculite contaminated with the Libby Amphibole
remains in buildings as an insulating material it is no longer manufactured, processed or distributed for
use in the United States and therefore is not considered a condition of use of asbestos for the purpose of
risk evaluation under TSCA.
2.2.2.2 Categories of Conditions of Use Included in the Scope of Risk
Evaluation
Table 2-3 summarizes the conditions of use for asbestos that EPA expects to consider in the risk
evaluation. Using the AM o L i EPA identified industrial processing or use activities, industrial
function categories and commercial and consumer use product categories. For risk evaluations, EPA
intends to consider the conditions of use for each life cycle stage and assess relevant potential sources of
release and human exposure associated with that life cycle stage (see Figure 2-1).
Reporting of asbestos in the 2016 Chemical Data Reporting (CDR) 3-4 period was limited (
2016b). Only two companies, both from the chlor-alkali industry, reported importing asbestos and the
amounts cannot be publicly disclosed due to company claims of confidential business information
(CBI).
Asbestos has not been mined or otherwise produced in the United States since 2002 (Flanap 16);
hence, mining is not included in the scope of the TSCA risk evaluation for asbestos. All asbestos used in
this country is imported. According to the U.S. Geological Survey (USGS), the only form of asbestos
2	Defined by 40 CFR 763.163 as "commercial uses of asbestos not identified in §763.165 the manufacture, importation or
processing of which would be initiated for the first time after August 25, 1989."
3	Manufacturers (including importers) are required to report under CDR if they meet certain production volume thresholds,
generally >25,000 lbs of a chemical substance at any single site. Reporting is triggered if the annual reporting threshold is
met during any of the calendar years since the last principal reporting year. In general, the reporting threshold remains 25,000
lbs per site. However, a reduced reporting threshold (2,500 lbs) now applies to some chemical substances, including asbestos,
subject to certain TSCA actions (U.S. EPA. 2017a).
4	For purposes of the CDR, manufacture means to manufacture, produce, or import for commercial purposes. Manufacture
includes the extraction, for commercial purposes, of a component chemical substance from a previously existing chemical
substance or complex combination of chemical substances. (40 CFR 711.3) (U.S. EPA. 2016c)
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currently imported into the United States is chrysotile, all of which originated from Brazil in 2017
(USGS, 2018). USGS reports that in 2017, the United States imported approximately 300 metric tons of
raw asbestos, the total of which they state is used in the chlor-alkali industry (USGS, 2018). In 2016, the
United States imported approximately 702 metric tons of raw asbestos (USGS, 2018). Other import data
presented in the USGS report are difficult to interpret with respect to volumes because most of the
asbestos-containing products reported are described in terms of monetary value and not import volume.
Also, the monetary value is associated with a product without reference to amount or type of asbestos
present in that product. EPA continues to work with its federal partners such as USGS and Customs and
Border Protection to better define import information on asbestos-containing products in support of
conducting the risk evaluation.
Table 2-3 provides a listing of the conditions of use of asbestos intended, known, or reasonably foreseen
to be considered under the TSCA risk evaluation for asbestos. The conditions of use identified in the
Scope document have been refined as part of the problem formulation process. Table 2-3 reflects the
updated list of conditions of use, identified by asbestos product category, and provides examples for
how each product is used. Information provided in Table 2-3 is also reflected the Life Cycle Diagram,
Figure 2-1.
Table 2-3. Categories of Conditions of Use Included in the Scope of the Risk Evaluation
Activity
Product Category
Kxamplc
Known,
Intended, or
Reasonably
Foreseen Use
Asbestos Diaphragms
Chlor-alkali Industry
Sheet Gaskets
Chemical Manufacturing
Oilfield Brake Blocks
Oil Industry
Aftermarket Automotive Brakes/Linings
Passenger Vehicles

Other Vehicle Friction Products
Non-passenger Vehicles

Asbestos Cement Products
Cement pipe

Other Gaskets and Packing
Equipment Seals

Woven Products
Imported Textiles
Most of the asbestos-containing products listed in the categories in Table 2-3 are primarily associated
with industrial and commercial use. It is important to note that the import volume of products containing
asbestos is not known.
2.2.2.3 Overview of Conditions of Use and Life Cycle Diagram
The life cycle diagram provided in Figure 2-1 depicts the conditions of use that are within the scope of
the risk evaluation during various life cycle stages including manufacturing, processing, distribution, use
(industrial, commercial, consumer) and disposal. Additions or changes to the conditions of use based on
additional information gathered or analyzed during problem formulation are described in Sections
2.2.2.1 and 2.2.2.2. The activities that EPA determined are out of scope during problem formulation are
not included in the life cycle diagram.
Use categories include the following: "industrial use" means use at a site at which one or more
chemicals or mixtures are manufactured (including imported) or processed. "Commercial use" means
the use of a chemical or a mixture containing a chemical (including as part of an article) in a commercial
enterprise providing saleable goods or services. "Consumer use" means the use of a chemical or a
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mixture containing a chemical (including as part of an article, such as furniture or clothing) when sold to
or made available to consumers for their use (U.S. EPA, 2017a).
To understand conditions of use relative to one another and associated potential exposures under those
conditions of use, the life cycle diagram includes the production volume associated with each stage of
the life cycle, as reported in the 2016 CDR reporting (	,017a) when the volume was not
claimed confidential business information (CBI). However, in the case of asbestos, reported USGS
production volume was used since the CDR production volume was claimed CBI.
Descriptions of the industrial, commercial and consumer use categories included in the life cycle
diagram are summarized below. The descriptions provide a brief overview of the use category;
Appendix B contains more detailed descriptions (e.g., process descriptions, worker activities) for each
manufacture, processing, distribution, use and disposal category.
Figure 2-1 depicts the life cycle diagram of asbestos from manufacture to the point of disposal.
Activities related to distribution (e.g., loading, unloading) will be considered throughout the asbestos life
cycle, rather than using a single distribution scenario.
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MRS/IMPORT
PROCESSING
INDUSTRIAL, COMMERCIAL, CONSUMER USES
RELEASES and WASTE DISPOSAL
Manufacture
(Non-U.S, Mining)
import of Raw Asbestos:
300 Metric Ions
(2013 USG5)
Asbestos- Containing
Diaphragms
Fabrication of
Asbe stosrConta i n i ng
Diaphragms
(Chloralkali Industry)
Use: 300 Metric Tons
(15 sites)
Import [Contained
within Imported
Products)
Unknown
Oilfield Brake Blocksb
Aftermarket Auto Brakes/
Linings'
Other Vehicle Friction
Productsr
Woven Productsc
Cement Products1
Other gaskets and packing
Asbestos Sheets
(Stamping/Cutting)
Asbestos-Containing Sheet
Gaskets a
Emissions to Air
Wastewater d
Liquid Wastes d
Solid Wastes
See Figure 2-4 for Environmental
Releases and Wastes
At the level of detail in the life cycle diagram,
there is no distinction between
industrial/commercial/consumer uses. The
differences between these uses will be further
i n ve stigate d a n d d e f in ed i n th e ri sk e va I u ation
process.
Figure 2-1. Asbestos Life Cycle Diagram
The life cycle diagram depicts the conditions of use that are within the scope of the risk evaluation during various life cycle stages including manufacturing, processing, use (industrial, commercial, consume),
distribution and disposal. The import volume shown isfrom2018USGS. Import volumes of asbestos-containing products are unknown. Activities related to distribution (e.g., loading, unloading, etc.) will be
considered throughout theasbestos life cycle, raths than using a single distribution scenario.
s Sheet gaskets were identified during public commait period.
b Oilfieldbrake blocks identified via industry response during problem formulation.
c Data is very limited forthese uses.
d Wastewater: combination of water and organic liquid, where the organic content is less than 50 paxait. Liquid Wastes: combination of water and organic liquid, where the organic content is greater than 50
percent

-------
EPA is aware of the use of raw imported chrysotile asbestos in the chlor-alkali industry, the use of
imported asbestos-containing sheet gaskets in the manufacture of titanium dioxide, the use of imported
asbestos-containing brake blocks in the oil industry, and other imported asbestos-containing products
that could be used either in industrial or consumer settings.
Diaphragms in Chlor-alkali Industry
The chlor-alkali industry imports raw chrysotile asbestos for use in semipermeable diaphragms, which
separate the anode from the cathode chemicals in the production of chlorine and sodium hydroxide
(caustic soda) (USGS, 2017). During a meeting with EPA in January 2017, industry representatives
stated that in the United States, there are three companies (Olin Corporation, Occidental Chemical and
Axial/Westlake Corporation) who own a total of 15 chlor-alkali plants that continue to fabricate and use
asbestos (chrysotile)-containing semipermeable diaphragms onsite.
EPA conducted a site visit of two chlor-alkali plants in March 2017 and observed the methods described
at the January industry meeting. EPA also learned about the automated process wherein raw imported
asbestos is processed and diaphragms are constructed. EPA continues to evaluate how representative the
processes witnessed at these two facilities are of processes at other plants when evaluating this use in the
analysis phase of the risk evaluation. EPA held a conference call with Axial/Westlake on April 11, 2017
to discuss their use of asbestos diaphragms at their Plaquemine, LA plant (EPA-HQ-	)736-
). EPA also had follow-up meetings with Occidental Chemical on September 6, 2017, (EPA-HQ-
3 Jill *)and Olin Chemical on September 14, 2017 (EP A-HQ-QPPT-2016-073* in Q
to better understand the use, processes (including personal protective equipment and engineering
controls used) and disposal methods followed for asbestos diaphragms.
Sheet Gaskets
During the public comment period, one chemical production company, Chemours, notified EPA of their
current use of imported gaskets from China (Comment ID (	-0067). These
sheet gaskets are composed of 80% (minimum) chrysotile asbestos, encapsulated in Styrene Butadiene
Rubber, and used to create tight chemical containment seals during the production of titanium dioxide.
On October 30, 2017, EPA met with both the commenter, Chemours, and their gasket supplier, Branham
Corporation, who provided EPA with additional information on the fabrication and use of the gaskets
(1 I' \ 11'3-OPPT-2016-0736-0119). Branham imports rubberized sheets of the asbestos-containing
material from a manufacturer in China and then fabricates (by cutting to specific sizes) the gaskets from
the sheet material. Chemours informed EPA during the meeting that asbestos-containing gaskets are
optimal because they are resistant to cyclical high temperatures and immense pressure. During the
manufacture of titanium dioxide, temperatures can exceed 1850 degrees Fahrenheit and pressures can be
greater than 50 pounds per square inch.
Brake Blocks in Oilfields
During problem formulation, EPA contacted a domestic brake blocks manufacturing company to
confirm that asbestos brake blocks are still used in oilfield equipment within the United States
(https//www. regulations, gov/docume nt ^ > \ >' VUQ n \ I .-0 , . m iM \ HQj" _0i
0736-0118). Although the company no longer fabricates brake blocks using asbestos, the company did
confirm that they import asbestos-containing brake blocks on behalf of some clients for use in the
oilfield industry. It is unclear how widespread the continued use of asbestos brake blocks is for use in
oilfield equipment, but EPA understands from interactions with industry that the use of asbestos brake
blocks has decreased significantly over time and continues to decline. EPA continues to investigate the
use of this product.
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Asbestos Containing Products for Commercial and Consumer Use
EPA found limited evidence of asbestos-containing products currently used in the United States. In the
scope document, certain asbestos-containing products, such as cement products, aftermarket brake
linings, other vehicle friction materials, and other gaskets and packing were identified in the Preliminary
• , -> >, on Manufacturing, Processing, Distribution, Use, and Disposal: Asbestos (Docket: 1
U'-\ ' '" '*'11'' !' i ,i I <>) During problem formulation, EPA consulted with
USGS staff on what uses of asbestos they consider to be ongoing based on their professional judgement
after reviewing government and commercial trade databases. USGS believes that the asbestos-
containing products that continue to be imported include raw chrysotile asbestos (for use in chlor-alkali
diaphragms), asbestos brake linings (automotive brakes/linings, other vehicle friction products), knitted
fabrics (woven products), asbestos rubber sheets (i.e., sheet gaskets) and asbestos cement products.
USGS and EPA believe that other asbestos imports listed by harmonized tariff schedule (HTS) code in
government and commercial trade databases are likely misreported and are not ongoing current
conditions of use.
2.3 Exposures
For TSCA exposure assessments, EPA expects to evaluate exposures and releases to the environment
resulting from the conditions of use applicable to asbestos. Post-release pathways and routes will be
described to characterize the relationship between the conditions of use of the chemical and the exposure
to human receptors, including potentially exposed or susceptible subpopulations and ecological
receptors. EPA will take into account, where relevant, the duration, intensity (concentration), frequency
and number of exposures in characterizing exposures to asbestos.
2.3.1 Fate and Transport
Environmental fate includes both transport and transformation processes. Environmental transport is the
movement of the chemical within and between environmental media. Transformation occurs through the
degradation or reaction of the chemical with other species in the environment. Hence, knowledge of the
environmental fate of the chemical informs the determination of the specific exposure pathways and
potential human and ecological receptors EPA expects to consider in the risk evaluation. EPA has
identified and considered environmental fate data as reported in several assessments in developing the
scope and problem formulation for asbestos (Wlii1 Al14; IARC, 2012; ATS UK A'*-' l).
Asbestos fibers are largely chemically and biologically inert under environmental conditions. They may
undergo minor physical changes, such as changes in fiber length or leaching of surface minerals, but do
not degrade, react or dissolve to any appreciable extent in the environment (IARC, 2012; ATSDR,
2001). Asbestos fibers can be found in soils, sediments, lofted in air and windblown dust, surface water,
ground water and biota (IARC, 2012; ATSDR, 2001). Small asbestos fibers (<1 pm) remain suspended
in air and water for a significant period of time and may be transported over long distances (ATSDR,
2001). Chrysotile asbestos forms stable suspensions in water and degrades to some extent in acidic
conditions, however the silicate structure remains intact (IARC, 2012). Asbestos fibers will eventually
settle to sediments and soil, and movement therein may occur via erosion, runoff or mechanical
resuspension (wind-blown dust, vehicle traffic, etc.) (WHO, 2014).
Asbestos may be released to the environment through industrial or commercial activities, such as
processing raw asbestos, fabricating/processing asbestos containing products, or the lofting of friable
asbestos during use, disturbance and disposal of asbestos containing products. Systematic literature
review is currently underway to determine if any new information may inform the development of the
risk evaluation.
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2.3.2 Releases to the Environment
Releases to the environment from conditions of use (e.g., industrial and commercial processes,
commercial or consumer uses resulting in down-the-drain releases) are one component of potential
exposure and may be derived from reported data that are obtained through direct measurement, and
estimations based on empirical data and/or assumptions and models.
A source of information that EPA considered in evaluating exposure are data reported under the Toxics
Release Inventory (TRI) program. Under the Emergency Planning and Community Right-to-Know Act
(EPCRA) Section 313, asbestos (friable) is a TRI-reportable substance effective January 1, 1987.
EPA's TRI data contains information about asbestos releases to air and water and disposal to land from
industrial facilities in covered sectors in the United States. For TRI reporting, facilities in covered
sectors are required to report releases or other waste management of only the friable form of asbestos,
under the general CASRN 1332-21-4. TRI interprets "friable" under EPCRA Section 313, referring to
the physical characteristic of being able to be crumbled, pulverized or reducible to a powder with hand
pressure, and "asbestos" to include the six types of asbestos as defined under Title II of TSCA.5
Facilities are required to report if they are in a covered industrial code and manufacture (including
import) or process more than 25,000 pounds of friable asbestos, or if they otherwise use more than
10,000 pounds of friable asbestos.
Table 2-4 provides production-related waste management data for friable asbestos reported by industrial
facilities in covered sectors to the TRI program for 2015. In 2015, 36 facilities reported a total of
approximately 25 million pounds of friable asbestos waste managed. Of this total, zero pounds were
recovered for energy, approximately 188,000 pounds were treated, and nearly 25 million pounds were
disposed of or otherwise released into the environment. It was determined during problem formulation
that the 875 pounds of recycled material reported to TRI for 2015 was in error (error correction
pending).
Table 2-4. Summary of Asbestos TRI Production-Related Waste Managed in 2015 (lbs)





Total
Number of

Knergv


Production
Facilities
Recycling
Recovery
Trent mo ill
Releasesllhl
Related Waste
36
875
0
188,437
25,360,853
25,550,164
Data source: U.S. EPA (2017d).




3 Terminology used in these columns may not match the more detailed data element names used in the TRI public data and
analysis access points.




b Does not include releases due to one-time event not associated with production such as remedial actions or earthquakes.
c Counts all releases including release quantities transferred and release quantities disposed of by a receiving facility
reporting to TRI.





Table 2-5 provides a summary of asbestos TRI releases to the environment in 2015. There were zero
pounds of friable asbestos reported as released to water via surface water discharges, and a total of 3 14
5 According to 53FR4519 (VII)C(5), "The listing for asbestos is qualified by the term "friable." This term refers to a physical
characteristic of asbestos. EPA interprets "friable" as being crumbled, pulverized, or reducible to a powder with hand
pressure. Again, only manufacturing, processing, or use of asbestos in the friable form triggers reporting. Similarly, supplier
notification applies only to distribution of friable asbestos."
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pounds of air releases from collective fugitive and stack air emissions. The vast majority of friable
asbestos was disposed of to landfills from both Resource Conservation and Recovery Act (RCRA)
Subtitle C landfills and to landfills other than RCRA Subtitle C.
Table 2-5. Summary of Asbestos TRT Releases to the Environment in 2015 (lbs)

\uiiiIxt
of
lacililics
Air Releases
Wilier
Releases
Ixind l)is|Misal
Oilier
Releases
.1
Total On-
aml OIT-Siic
l)is|«>sal or
Oilier
Releases ''


Slack Air
Releases'1
l;ii:>ilnc
Air
Releases'

(lass 1
I nticr-
•> round
Injection
RC RA
Suhiiilc (
l.antllllls
All oilier
1 .anil
l)is|x>sal ¦'


Subtotal

106
208

0
9,718,957
15,849,020


Totals
36
314
0
25,567,977
0
25,568,292
Data source: U.S. EPA (2017d).
s T erminologyusedin these columns may not match the more detailed data elem ait names used in the TRI public data and analysis access points.
b These release quantities do include releases due to one-time events not associated with production such as remedial actions or earthquakes.
1 Counts release quantities once at final disposition, accounting for transfers to other TRIreporting facilities that ultimately dispose ofthe chemical waste.
d Point source (stack) air emissions are releases to airthat occur through confined air streams, such as stacks, ducts or pipes.
c Fugitive air emissions are emissions that do not occur through a confined air stream, which may include equipment leaks, releases from building ventilation
systems, and evaporative losses from surface impoundments and spills.
While production-related waste managed shown in Table 2-4 excludes any quantities reported as
catastrophic or one-time releases (TRI section 8 data), release quantities shown in Table 2-5 include
both production-re la ted and non-routine quantities (TRI section 5 and 6 data) for 2015. As a result,
release quantities may differ slightly and may further reflect differences in TRI calculation methods for
reported release range estimates (TTC 1 u " „
From TRI data available using TRI Explorer, Table 2-6 shows that there has been a relatively large
increase in total on-site and off-site disposal or other releases of friable asbestos since 2009 [EPA-HQ'
CPFT-2016-0736-0005 (U S FP 201 HQ"|. From 2009 to 2015, total on-site and off-site disposal or
other releases of friable asbestos have risen from 8.8 million pounds to nearly 25.6 million pounds,
respectively. As previously noted, the vast majority of the total on-site and off-site disposal or other
releases of friable asbestos are released to land. Release quantities to other media sources such as air are
of much smaller magnitude. It is important to note that quantities released from surface water discharges
have been zero pounds since 2009. The industry accounting for the highest release quantities of friable
asbestos is the hazardous waste treatment and disposal sector, followed by the petroleum and other
chemical and electric sectors.
Table 2-6. Total On- and Off-site Disposal or Other Releases of Friable Asbestos (lbs) (2009-2015),
based on TRI Data
Ye sir
Total On- and OIT-site Disposal or Oilier Releases (lbs)
2009
8,757,577
2010
13,015,169
2011
12,492,732
2012
16,018,091
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Year
Total On- and Oil-she Disposal or Oilier Releases (Ihs)
2013
16,641,975
2014
17,521,650
2015
25,568,291
Other sources of information provide evidence of releases of asbestos, including EPA effluent guidelines
(EGs) promulgated under the Clean Water Act (CWA), National Emission Standards for Hazardous Air
Pollutants (NESHAPs) promulgated under the Clean Air Act (CAA); or other EPA standards and
regulations that set legal limits on the amount of asbestos that can be emitted to a particular media.
In addition to TRI data, EPA has also received release information from industry that will be used in the
risk evaluation (see Section 2.6.1.3).
2.3.3	Presence in the Environment and Biota
Monitoring studies or a collection of relevant and reliable monitoring studies provide(s) information that
can be used in an exposure assessment. Monitoring data were identified in EPA's data search for
asbestos.
Presence of asbestos libers in the air is highly variable, although there typically is a 10-fold higher
concentration of asbestos in cities (0.0001 fibers/ml) than in rural areas (0.00001 fibers/ml) (ATSDR.
2001).
In 2001, the U.S. drinking water supplies generally had asbestos concentrations <1 million fibers per
liter (MFL), although some locations may contain 10-300 MFL (ATSDR, 2001).
Available data (although over 30 years old) indicate asbestos has been detected in many different
freshwater fishes and mussels from bodies of water contaminated with asbestos (	30b;
Shuff	).
Asbestos fibers have been measured in U.S. municipal sewage sludges, with asbestos fiber content up to
10% of ashed sludge by volume (ATSDR, 2001). Biosolids in the U.S. may be disposed of by land
application, land filling, or incineration. However, in the most recent EPA biosolids review, asbestos
was not detected (see Section 2.5.3.2).
2.3.4	Environmental Exposures
The manufacturing, processing, distribution, use, and disposal of asbestos can result in releases to the
environment. EPA expects to consider exposures to the environment and ecological receptors that occur
via the exposure pathways or media shown in the revised conceptual model, Figure 2-4, in conducting
the risk evaluation for asbestos.
The physical chemical properties of asbestos indicate that fibers can settle over time into sediments from
surface water. The larger the fiber, the faster it will settle.
Compliance monitoring data, available for 2006-2011 shows 214 systems (3.7% of 5,785 systems) had
detects greater than the minimum reporting level (MRL) of 0.2 MFL but only 8 systems had detects of
asbestos greater than the MCL of 7 MFL (https://www.epa.gov/dwsixvearreview/six-vear-review-3-
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compliance- monitoring-data-2006-2011). Data from 1998-2005 showed 268 systems (3.2% of 8278
systems) had detects >the MRL of 0.2 MFL but only 14 (0.169%) systems had detects of asbestos
greater than the MCL of 7 MFL (https//www.epa.gov/dwsixvearreview/six-vear-review-2-drinking-
water-standards).
A source of information that EPA expects to consider in evaluating surface water releases are data
reported in EPA's Discharge Monitoring Report (DMR) Pollutant Loading Tool
(https://cfpub.epa.gov/dinr/) to identify facilities that discharge asbestos to surface water. Information
was obtained from the DMR Pollutant loading tool accessed on December 1, 2017. Facilities were
identified using "EZ Search" which identifies facilities that submit Discharge Monitoring Reports
(DMRs). Searches were conducted for the two most current (and complete) years in the tool: 2015 and
2016. Only one DMR facility was identified in 2014 and 2015 and this facility was a mining facility and
may be related to legacy mining use runoff Asbestos has not been mined or otherwise produced in the
United States since 2002. EPA did not consider legacy releases or releases based on naturally occurring
background levels in this assessment.
2.3.5 Human Exposures
EPA plans to analyze occupational, consumer and general population exposures. Subpopulations,
including potentially exposed and susceptible subpopulations, within these exposed groups will also be
considered.
The physical condition of asbestos is an important factor when considering the potential human
pathways of exposure. Several of the asbestos-containing products identified as conditions of use of
asbestos (refer to Section 2.2.2.2) are not friable as intact products; however, non-friable asbestos can be
made friable due to physical and chemical wear and normal use of asbestos-containing products.
Exposures to asbestos can potentially occur via all routes; however, EPA anticipates that the most likely
exposure route is inhalation for all of the subpopulations considered (see discussion in Section 2.4.2).
2.3.5.1 Occupational Exposures
Exposure pathways and exposure routes are listed for worker activities under the various conditions of
use described in Section 2.2. In addition, occupational non-users (ONU), who do not directly handle
asbestos but perform work in an area where the chemical is present are listed. Engineering controls
and/or personal protective equipment may impact occupational exposure levels.
EPA considers inhalation of asbestos fibers to be the most likely asbestos exposure pathway for workers
and occupational non-users during the conditions of use included in Sections 2.2.2.2 and 2.2.2.3. These
include the fabrication of asbestos-containing diaphragms in the chlor-alkali industry, use of asbestos-
containing gaskets in the production of titanium dioxide, and the use of asbestos containing brake blocks
in the oil industry. Workers and occupational non-users may also be exposed to asbestos containing
products (e.g., friction products, cement products, other gaskets and packing, woven products) that may
become friable during use or handling. EPA will only evaluate the inhalation route of exposure (see
Section 2.4.2 for discussion).
Workers and occupational non-users may be exposed to asbestos when performing activities associated
with conditions of use described in Section 2.2.2.3 including, but not limited to:
• Unloading and transferring raw asbestos to and from storage containers to storage rooms,
process equipment or glove boxes in the chlor-alkali industry;
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•	Using asbestos within process equipment (e.g., fabrication of diaphragms in the chlor-alkali
industry);
•	Cleaning and maintaining equipment in the chlor-alkali industry;
•	Using imported and/or aftermarket asbestos-containing products (e.g., oilfield equipment
maintenance);
•	Processing and using imported sheet gaskets;
•	Cutting cement pipes;
•	Changing asbestos-containing automotive brakes;
•	Handling, transporting and disposing waste containing asbestos in chlor-alkali plants and
other industrial facilities handling asbestos.
Key data that inform occupational exposure assessment include: the OSHA Chemical Exposure Health
Data (CEHD) and NIOSHHealth Hazard Evaluation (HHE) program data. OSHA data are workplace
monitoring data from OSHA inspections. The inspections can be random or targeted, or can be the result
of a worker complaint. OSHA data can be obtained through the OSHA Integrated Management
Information System (1M1S) at https://www.osha.gov/oshstats/index.html. Table Apx B-1 in Appendix B
provides a summary of industry sectors with asbestos personal monitoring air samples obtained from
OSHA inspections conducted between 2011 and 2016 (the data were received [October 25th, 2017] and
are being evaluated). NIOSH HHEs are conducted at the request of employees, union officials, or
employers and help inform potential hazards at the workplace. HHEs can be downloaded at
https://www.cdc. gov/niosh/hhe/ . In addition, occupational monitoring information was received from
companies in the chlor-alkali and sheet gasket industries; some of this data has been claimed CBI. EPA
will review these data and evaluate their utility in the risk evaluation.
According to OSHA asbestos standards, the employee permissible exposure limit (PEL) is 0.1 fibers per
cubic centimeter (free) as an 8-hour, time-weighted average (TWA) and/or the excursion limit (1.0 free
asa30-minute TWA) (Asbestos General Standard \	) The NIOSH Recommended Exposure
Limit (REL) (N 2007) and the American Conference of Governmental Industrial Hygienists
Threshold Limit Value (ACGIH TLV) (/	) are also 0 1 free (respirable fibers), with the REL
duration of 100 minutes. Both the PEL and REL are based on phase contrast microscopy (PCM) (which
would not include fibers with diameters less than approximately 0.25 pm).
2.3.5.2	Consumer Exposures
Through further investigation of the list of products available for purchase on the internet as depicted in
Section 3 of the Preliminary Information on Manufacturing, Processing, Distribution, Use, and
Disposal: Asbestos document EPA-HQ-OPPT-2016-0736-0005, (U.S. EPA 2017b), EPA has
determined that asbestos-containing consumer products are likely imported only, not produced in the
United States, and are limited to aftermarket friction materials. Available data suggest woven products
could also be imported and used by consumers in the United States.
Exposure routes for consumers using asbestos-containing products may include inhalation of
particulates resulting from use, and there is the possibility that clothing contaminated from asbestos
through product use or manipulation could result in exposures to asbestos. EPA will only evaluate the
inhalation route of exposure (see Section 2.4.2 for discussion).
2.3.5.3	General Population Exposures
Asbestos is a naturally occurring mineral and is therefore present in the environment. Thus, the general
population may be exposed to low levels of naturally occurring asbestos (ATSDR, 2.001). Asbestos
fibers may potentially be released during processing or use of asbestos in industry and use of imported
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asbestos containing products (see Section 2.3.2 and the public docket EPA-HQ-QPPT-2016-0736). As
explained in Section 2.3.2, only friable asbestos above a specified threshold is required to be reported to
the Toxics Release Inventory. Therefore, other sources of air releases will be consulted in the risk
evaluation. For example, EPA will evaluate the data that has been submitted by the chlor-alkali and
gasket industries as well as other sources of data.
2.3.5.4 Potentially Exposed or Susceptible Subpopulations
TSCA requires the determination of whether a chemical substance presents an unreasonable risk to "a
potentially exposed or susceptible subpopulation identified as relevant to the risk evaluation" by EPA.
TSCA § 3(12) states that "the term 'potentially exposed or susceptible subpopulation' means a group of
individuals within the general population identified by the Administrator who, due to either greater
susceptibility or greater exposure, may be at greater risk than the general population of adverse health
effects from exposure to a chemical substance or mixture, such as infants, children, pregnant women,
workers, or the elderly." General population is "the total of individuals inhabiting an area or making up a
whole group" and refers here to the U.S. general population (	.011).
As part of the Problem Formulation, EPA identified potentially exposed and susceptible subpopulations
for further analysis during the development and refinement of the life cycle, conceptual models,
exposure scenarios, and analysis plan. In this section, EPA addresses the potentially exposed or
susceptible subpopulations identified as relevant based on greater exposure. EPA will address the
subpopulations identified as relevant based on greater susceptibility in the hazard section.
EPA identifies the following as potentially exposed or susceptible subpopulations that EPA expects to
consider in the risk evaluation due to their greater exposure:
•	Workers and occupational non-users
•	Consumers and bystanders associated with consumer use. Asbestos has been identified as
being used in products available to consumers; however, only some individuals within the
general population may use these products. Therefore, those who do use these products are a
potentially exposed or susceptible subpopulation due to greater exposure.
•	Other groups of individuals within the general population who may experience greater
exposures due to their proximity to conditions of use identified in Section 2.2.2.2 that result
in releases to the environment and subsequent exposures (e.g., individuals who live or work
near manufacturing, processing, use or disposal sites).
In developing exposure scenarios, EPA will analyze available data to ascertain whether some human
receptor groups may be exposed via exposure pathways that may be distinct to a particular
subpopulation or life stage (e.g., children's crawling, mouthing or hand-to-mouth behaviors) and
whether some human receptor groups may have higher exposure via identified pathways of exposure
due to unique characteristics (e.g., activities, duration or location of exposure) when compared with the
general population (	06).
The population most likely to have high exposure to asbestos are workers who come into contact with
asbestos while on the job (ATSDR, 2001). In the Scope document, fire fighters were also included as a
potentially exposed or susceptible subpopulation. However, fire fighters will be exposed to materials
that are predominately legacy uses, which will not be evaluated in the risk evaluation.
In summary, in the risk evaluation for asbestos, EPA plans to analyze the following potentially exposed
groups of human receptors including: workers, occupational non-users, consumers, bystanders
associated with consumer use, and other groups of individuals within the general population who may
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experience greater exposure. EPA may also identify additional potentially exposed or susceptible
subpopulations that will be considered, based on greater exposure.
2.4 Hazards (Effects)
For scoping, EPA conducted comprehensive searches for data on hazards of asbestos, as described in
Strategy for Conducting Literature Searches for Asbestos: Supplemental File for the TSCA Scope
Document (L> \ 1 JQUVP 3' :01 * >~0 ;36). Based on initial screening, EPA plans to analyze the hazards of
asbestos identified in this scope document. However, when conducting the risk evaluation, the relevance
of each hazard within the context of a specific exposure scenario will be judged for appropriateness. For
example, hazards that occur only as a result of chronic exposures may not be applicable for acute
exposure scenarios. This means that it is unlikely that every hazard will be analyzed for every exposure
scenario.
2.4.1 Environmental Hazards
EPA identified the following sources of environmental hazard data for asbestos: 45 FR 79318, 1980
ATSDR > V I b. EPA (2014c); i ^ ^ ; 2014b); WHO (2014); and I \RC (2012). In addition,
EPA conducted a literature search to identify additional environmental hazard data for asbestos as
identified in the literature search conducted by the Agency for asbestos {Asbestos (CASRN1332-21-4)
Bibliography: Supplemental File for the TSCA Scope Document,	)~QPPT~2016-0736). Only the
on-topic references listed in the Ecological Hazard Literature Search Results were considered as
potentially relevant data/information sources for the risk evaluation. Inclusion criteria were used to
screen the results of the ECOTOX literature search (as explained in the Strategy for Conducting
Literature Searches for Asbestos: Supplemental File for the TSCA Scope Document, EPA-HQ - OPPT-
2016-0736). Data from the screened literature are summarized below (Table 2-7. Ecological Hazard
Characterization ofChrysotile Asbestos (CASRN 12001-29-5) as ranges (min-max). EPA plans to
review these data/information sources during risk evaluation using the data quality review evaluation
metrics and the rating criteria described in the Application of Systematic Review in TSCA Risk
Evaluations (U.S. EPA, 2018).
Data were available for aquatic organisms (vertebrates, invertebrates and plants) and terrestrial species
(earthworms and plants). For problem formulation, a screening evaluation was conducted using aquatic
toxicity studies characterizing the effects of chronic exposure of chrysotile asbestos to aquatic
invertebrates and fish, presented in Table 2-7. Ecological Hazard Characterization of Chrysotile
Asbestos (CASRN 12001-29-5)Preliminary review of these studies indicates that chronic exposure to
waterborne chrysotile asbestos may result in reproductive, growth and sublethal effects to these taxa at a
concentration range of 104-108 fibers/L (i.e., 0.01-100 MFL). A comparison to available monitoring data
(see Section 2.6.1.2) preliminarily indicates exposure concentrations may be within the same order of
magnitude; hence, EPA will further evaluate this pathway.
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Table 2-7. Ecological Hazard Characterization of Chrysotile Asbestos (CASRN 12001-29-5)
Duration
Test Organism
Mndpiiinl
lla/anl Value 1 I nil
ITTeii lji(l|«>inl(s)
Uelereiu'es
Aquatic Organisms
Chronic
Fish
NOECb
0.01-1.5
MFLe
Behavioral stress (aberrant
swimming, loss of
equilibrium); Egg
development, hatchability,
survival; Growth; Mortality
Belanger (1985);
Belanger et al.
t J); Belanger
et al. (1986c);
Cairns et al.
(1990)
LOECc
1-3
ChVd
0.1-2.12
Aquatic
invertebrates
LOEC
0.0001-100
MFL
Reduction in siphoning
activity; # of larvae released;
Alterations of gill tissues;
Fiber accumulation in tissues;
Growth; Mortality
Belanger et al.
'Ml
Aquatic Plant
LOEC
0.5
Hg
chrysotile/
frond
# of fronds; Root length;
Chlorophyll content;
Carotenoid content; Biomass
of fronds; Protein content; Free
sugar; Starch; Photo synthetic
pigments; Lipid peroxidation;
Cellular hydrogen peroxide
levels; Catalase activity;
Superoxide Dismutase
Trivedi et al.
(2004); Trivedi
et al. (2007)
Terrestrial Organisms
Chronic
Terrestrial Plant
ChV
No observed
effects
N/Af
Growth
Miller et al,
£12
11 Values in the tables are presented as reported by the study authors.
bNOEC, No Observable Effect Concentration
cLOEC, Lowest Observable Effect Concentration
dChV, Chronic Value; Calculated using the geometric mean ofLOEC and NOEC values Tas described EPA (2013)1.
eMFL, Million Fibers/Liter
fN/A, Not applicable
For additional perspective on understanding the environmental hazard of asbestos materials, EPA/OPPT
reviewed other, related documents on asbestos materials not considered under TSCA. For example, EPA
Region 8 reviewed the same data identified above for the Libby Superfund Site ecological risk
assessment (U.S. EPA, 2014b) and considered it relevant; thus suggesting the experiments/information
reasonably describes the aquatic hazard of asbestos. However, Region 8 decided to perform in situ
studies to specifically evaluate ecological receptor effects following exposure to Libby Amphibole
Asbestos (LAA, or LA in the report). During the course of performing these experiments/exposures,
Region 8 found them difficult to conduct and quantify, thus highlighting the difficulty of evaluating
asbestos/asbestiform fibers in ecological receptors.
2.4.2 Human Health Hazards
Asbestos has an existing EPA IRIS Assessment and an ATSDR Toxicological Profile; hence, many of
the hazards of asbestos have been previously compiled and reviewed. EPA relied heavily on these
comprehensive reviews in preparing the scope and problem formulation documents. EPA expects to use
these documents as a starting point for identifying key and supporting studies to inform the human
health hazard assessment, including dose-response analysis. EPA also expects to consider other studies
that have been published since these reviews, as identified in the literature search conducted by the
Agency for asbestos (Asbestos (CASRN 1332-21-4) Bibliography: Supplemental File for the TSCA
Scope Document, EPA-HQ-QPPT-2016-0736). The preponderance of information in these assessments
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is based on inhalation exposures to human populations. Only inhalation exposures in humans will be
evaluated in the risk evaluation of asbestos. The relevant studies will be evaluated using the data quality
criteria in the Application of Systemic Review in TSCA Risk Evaluations document (	2018).
During scoping and problem formulation EPA reviewed the existing EPA IRIS health assessments to
ascertain the established health hazards and any known toxicity values. EPA had previously, in the IRIS
assessment on asbestos (1988), identified asbestos as a carcinogen causing both lung cancer and
mesothelioma from inhalation exposures and derived a unit risk to address both cancers. No toxicity
values or unit risks have yet been estimated for other cancers that have been identified by the
International Agency for Research on Cancer (IARC) and other government agencies. Given the well-
established carcinogenicity of asbestos for lung cancer and mesothelioma, EPA has decided to limit the
scope of its systematic review to these two specific cancers with the goal of updating, or reaffirming, the
existing unit risk. Asbestos may cause non-cancer health effects, with quantitative evidence coming
from the EPA Toxicological Review of Libby Amphibole Asbestos (U.S. EPA, 2014c). At a Target Risk
of 1 cancer per 1,000,000 people (1E-6), the existing EPA general asbestos toxicity value appears to be
the clear risk driver compared to the only existing EPA non-cancer toxicity value (R1C) for Libby
Amphibole Asbestos (U.S. EPA, ; ). Because cancer is expected to be the risk driver, in conducting
further analysis for the risk evaluation of asbestos, EPA will limit the scope of the risk evaluation to
lung cancer and mesothelioma in humans. No clear association was found for drinking water asbestos
exposure and cancer (NTP, 2016; IARC, 2012), and dermal exposures may cause non-cancerous skin
lesions. Since neither oral nor dermal exposures are expected to contribute to the risks of lung cancer
and mesothelioma, which are the basis of the 1988 cancer unit risk, exposures from the oral and dermal
routes will not be assessed. These hazards will be evaluated based on the specific exposure scenarios
identified for workers, consumers and the general population where applicable.
2.4.2.1 Cancer Hazard
Many authorities have established that there are causal associations between asbestos exposures and
lung cancer and mesotheliomas (NTP, 2016; IARC., 2012; ATSDR, 2001; U.S. EPA. 1988b; IARC,
1987, 1977). EPA also noted in the scope that there is a causal association between exposure to asbestos
and cancer of the larynx and cancer of the ovary (IARC, 2012), and that there is also suggestive
evidence of a positive association between asbestos and cancer of the pharynx (IARC, 2012; NRC,
2006), stomach	^vL2; ATSDR, 2001) and colorectum (N III i -NRC, 2012; NRC, 2006;
ATSDR, 2001; Ma	^ a 1980a). In addition, the scope document reported increases in
lung cancer mortality reported in both workers and residents exposed to various asbestos fiber types as
well as fiber mixtures (IARC, ) Mesotheliomas, tumors arising from the thin membranes that line
the chest (thoracic) and abdominal cavities and surround internal organs, are relatively rare in the
general population, but are often observed in populations of asbestos workers. All types of asbestos
fibers have been reported to cause mesothelioma (IARC., 2012).
During problem formulation, EPA reviewed the existing EPA IRIS health assessments (U.S. EPA,
2014c, 1988b) to ascertain the established health hazards and any known toxicity values. EPA had
previously (U.S. EPA, 1988b, 1986) identified asbestos as a carcinogen causing both lung cancer and
mesothelioma and derived a unit risk to address both cancers. The U.S. Institute of Medicine (NRC,
2006) and the International Agency for Research on Cancer (IARC, 2012) have evaluated the evidence
for causation of cancers of the pharynx, larynx, esophagus, stomach, colon, and rectum, and IARC has
evaluated the evidence for cancer of the ovary. Both the U.S. Institute of Medicine and IARC concluded
that asbestos causes cancer of the larynx and IARC concluded that asbestos causes cancer of the ovary.
No toxicity values or unit risks have yet been estimated for these other cancers.
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2.4.2.2 Potentially Exposed or Susceptible Subpopulations
TSCA requires that the determination of whether a chemical substance presents an unreasonable risk
include consideration of unreasonable risk to "a potentially exposed or susceptible subpopulation
identified as relevant to the risk evaluation" by EPA. TSCA § 3(12) states that "the term 'potentially
exposed or susceptible subpopulation' means a group of individuals within the general population
identified by the Administrator who, due to either greater susceptibility or greater exposure, may be at
greater risk than the general population of adverse health effects from exposure to a chemical substance
or mixture, such as infants, children, pregnant women, workers, or the elderly." In developing the hazard
assessment, EPA will analyze available data to ascertain whether some human receptor groups may have
greater susceptibility than the general population to asbestos.
2.5 Conceptual Models
EPA risk assessment guidance (	, ), defines Problem Formulation as the part of the
risk assessment framework that identifies the factors to be considered in the assessment. It draws from
the regulatory, decision-making and policy context of the assessment and informs the assessment's
technical approach.
A conceptual model describes the actual or predicted relationships between the chemical substance and
receptors, either human or environmental. These conceptual models are integrated depictions of the
conditions of use, exposures (pathways and routes), hazards and receptors. The initial conceptual models
describing the scope of the assessment for asbestos have been refined during problem formulation. The
changes to the conceptual models in this problem formulation are described along with the rationales.
In this section EPA outlines those pathways that will be included and further analyzed in the risk
evaluation; will be included but will not be further analyzed in risk evaluation; and will not b e included
in the TSCA risk evaluation and the underlying rationale for these decisions.
EPA determined as part of problem formulation that it is not necessary to conduct further analysis on
certain exposure pathways that were identified in the asbestos scope document and that remain in the
risk evaluation. Each risk evaluation will be "fit-for-purpose," meaning not all conditions of use will
warrant the same level of evaluation and the Agency may be able to reach some conclusions without
extensive or quantitative risk evaluations (82 FR 33726, J '«?«/.'9).
As part of this problem formulation, EPA also identified exposure pathways under other environmental
statutes, administered by EPA, which adequately assess and effectively manage exposures and for which
long-standing regulatory and analytical processes already exist, i.e., the Clean Air Act (CAA), the Safe
Drinking Water Act (SDWA), the Clean Water Act (CWA) and the Resource Conservation and
Recovery Act (RCRA). OPPT worked closely with the offices within EPA that administer and
implement the regulatory programs under these statutes. In some cases, EPA has determined that
chemicals present in various media pathways (i.e., air, water, land) fall under the jurisdiction of existing
regulatory programs and associated analytical processes carried out under other EPA-administered
statutes and have been assessed and effectively managed under those programs. EPA believes that the
TSCA risk evaluation should focus on those exposure pathways associated with TSCA uses that are not
subject to the regulatory regimes discussed above because these pathways are likely to represent the
greatest areas of concern to EPA. As a result, EPA does not expect to include in the risk evaluation
certain exposure pathways identified in the asbestos scope document.
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2.5.1 Conceptual Model for Industrial and Commercial Activities and Uses: Potential
Exposures and Hazards
The revised conceptual model (Figure 2-2) describes the pathways of exposure from industrial and
commercial activities and uses of asbestos EPA plans to include in the risk evaluation.
The population most likely to have high exposure to asbestos are workers who come into contact with
asbestos while on the job (ATSDR., 2001). As described in Section 2.2.2.2, EPA has confirmed the
ongoing industrial and commercial uses of asbestos in the chlor-alkali industry, brake blocks in oil
industry, and use of sheet gaskets in titanium dioxide production. These uses, as well as uses in other
products (brakes and other friction products, other gaskets, woven products, and cement products) will
continue to be investigated during the risk evaluation. All of these uses will be included in the risk
evaluation, as indicated in Figure 2-2.
EPA anticipates inhalation of asbestos fibers as being the most likely exposure route for workers and
occupational non-users. As discussed in Section 2.4.2, given the well-established carcinogenicity of
asbestos for lung cancer and mesothelioma, EPA will only evaluate these two specific cancers in the risk
evaluation (and associated systematic review) with the goal of updating, or reaffirming, the existing unit
risk.
In the Scope document, worker exposures via oral and dermal pathways were identified as potential
routes of exposure. However, since neither oral nor dermal exposures are expected to contribute to the
risks of lung cancer and mesothelioma, exposures from those routes (pathways) will not be included in
the risk evaluation.
Workers may be exposed via direct contact with dry or friable asbestos during waste handling, treatment
and disposal. This could occur during disposal of asbestos containing articles or wastes. When data and
information are available to support the analysis, EPA also considers the effect that engineering controls
and/or personal protective equipment have on occupational exposure levels.
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INDUSTRIAL ANDCOMMERCIAt	EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORS *	HAZARDS
ACTIVITIES/USES
Asbestos-tonta i n i ng
Diaphragms
Sheet Gaskets b
Oilfield brake blocks -
(e.g. Oilfield industry)
Aftermarket Auto
Brakes/Linings
Workers,
Occupational
Non-Users
Hazards Potentrafty Associated with
Asbestos Exposure
See Sect km 2.4.2
Outd oor/3 n d oor Ai r
Other Vehicle Friction
Products
Cement Products
Other Gaskets and
Packing
Woven Products
Direct Contact with
Dry/Fr? a b Se As bestos
WasteHandling,
Treatment and Disposal
Emissions to Wastewater,
Liquid Waste {See Figure 2-4)
Figure 2-2. Asbestos Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes and hazards to human receptors from industrial and commercial
activities and uses of asbestos.
a Receptors include potentially exposed or susceptible subpopulations.
b Sheet gaskets were identified during public comment period.
c Oilfield brake blocks identified via industry response during problem formulation.
d Asbestos cement products identified during problem formulation.
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2.5.2 Conceptual Model for Consumer Activities and Uses: Potential Exposures and
Hazards
Figure 2-3 presents the conceptual model for human populations from potential consumer uses of
asbestos. There are very few asbestos-containing products with ongoing uses that were identified and
confirmed during problem formulation. EPA identified the import of asbestos-containing automotive
brakes and linings and woven products as the only known, intended, or reasonably foreseen asbestos-
containing products that may have consumer exposure. These uses are included in Figure 2-3. Consumer
exposures will be difficult to evaluate since the quantities of these products that still might be imported
into the United States is not known.
Scenarios where consumers could be exposed and may be considered during risk evaluation include:
changing asbestos-containing brakes or brake linings or cutting or using asbestos-containing woven
products, and handling of asbestos waste that may result from these activities.
EPA anticipates inhalation of asbestos fibers as being the most likely exposure route for consumers. As
discussed in Section 2.4.2, given the well-established carcinogenicity of asbestos for lung cancer and
mesothelioma, EPA will only evaluate these two specific cancers in the risk evaluation (and associated
systematic review) with the goal of updating, or reaffirming, the existing unit risk.
In the Scope document, consumer exposures via oral and dermal pathways were identified as potential
routes of exposure. However, since neither oral nor dermal exposures are expected to contribute to the
risks of lung cancer and mesothelioma, exposures from those routes (pathways) will not be included in
the risk evaluation.
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CONSUMER ACTIVITIES/USES 3
EXPOSURE PATHWAY *	EXPOSURE ROUTE
RECEPTORS c
HAZARDS
Consumers,
Bystanders
1 n d oar/O utd oor Ai r
Inhalation
Aftermarket Auto Brakes
Woven Products
Consumer Handing of
Disposal and Waste
H aza rd s Potenti a Hy As soc iated with
Asbestos Exposure
See Section 2.4.2
Figure 2-3. Asbestos Conceptual Model for Consumer Activities and Uses: Potential Exposures and Hazards
aProducts may be used in both commercial and consumer applications.
b Products may be used during indoor and outdoor activities.
cReceptors include potentially exposed and susceptible subpopulations.
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2.5.3 Conceptual Model for Environmental Releases and Wastes: Potential Exposures
and Hazards
The revised conceptual model (Figure 2-4) illustrates the expected exposure pathways to human and
ecological receptors from environmental releases and waste stream associated with industrial and
commercial activities for asbestos. The pathway that EPA plans to include and analyze further in risk
evaluation is described in Section 2.5.3.1 and shown in the conceptual model. The pathways that EPA
plans to include but not further analyze in risk evaluation are described in Section 2.5.3.2 and the
pathways that EPA does not expect to include in risk evaluation are described in Section 2.5.3.3.
2.5.3.1 Pathways That EPA Expects to Include and Further Analyze in Risk
Evaluation
EPA plans to further analyze environmental releases from water pathways to aquatic species exposed via
contaminated surface water.
No releases to water have been reported to TRI for asbestos (Table 2-4). However, data submitted to
EPA from the chlor-alkali industry indicate that water releases may occur from these industries. Based
on data submitted to EPA from the chlor-alkali industry, who uses all of the raw asbestos imported into
the United States to fabricate asbestos-containing diaphragms, asbestos containing wastes generated in
their processes are disposed of according toNESHAP regulations established in 40 CFR 61.150.
Asbestos is not regulated as a hazardous waste under RCRA. Asbestos-containing diaphragms used in
the chlor-alkali processes may be reused at some of the plants. At the end of the diaphragms' life, water
is used to clean and remove the diaphragm from its frame. The wet diaphragm is bagged and landfilled
according to NESHAP regulations. Waste water from the washing of the diaphragm and frame is sent to
on-site waste water treatment; which may lead to eventual releases to water.
Asbestos-containing gaskets are used in the production of rutile/chlorine based titanium dioxide (Ti02).
Based on data submitted to EPA from the asbestos sheet gasket importer/processor, scrap pieces from
the gasket cutting process are double bagged and transported to landfills. EPA has been informed that
users of asbestos-containing gaskets dispose of spent gaskets primarily via incineration (3 onsite and 1
offsite facility) and RCRA Subtitle C landfill (1 facility). No water releases are anticipated.
Preliminary review of environmental studies indicates that chronic exposure to waterborne chrysotile
asbestos may result in reproductive, growth and sublethal effects. Compliance monitoring data,
available for 2006-2011 shows 214 systems (or 3.7% of 5,785 systems) with asbestos fiber
concentrations greater than the minimum reporting level (MRL) of 0.2 MFL, with asbestos
concentrations in 8 systems greater than the MCL of 7 MFL (https//www. epa. gov/dwsixyearreview/six-
year-review-3-compliance- monitoring-data-2006-2011). Data from 1998-2005 showed 268 systems (or
3.237% of 8278 systems) had asbestos fiber concentrations greater than or equal to the MRL of 0.2
MFL, with asbestos concentrations in 14 (0.169%) systems greater than the MCL of 7 MFL
(https://www.epa.gov/dwsixvearreview/six-vear-review-2-drinking-water-stai ).
As further explained in Section 2.5.3.2, EPA has not developed CWA section 304(a) recommended
water quality criteria for the protection of aquatic life for asbestos and there are no national
recommended criteria for this use available for adoption into state water quality standards and available
for use in NPDES permits. As a result, this pathway will undergo aquatic life risk evaluation under
TSCA (see Section 2.5.3.1).
Therefore, EPA plans to evaluate risks to aquatic species from exposures to asbestos in surface waters.
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2.5.3.2	Pathways That EPA Expects to Include in Risk Evaluation but Not Further
Analyze
As noted in Section 2.5.3.1 above, there are possible releases from conditions of use (i.e., chlor-alkali
plants) to water. Once in water, it will eventually settle into sediments (or possibly biosolids from
wastewater treatment plants).
EPA does not expect to perform a lull analysis of exposures to asbestos fibers to sediment-dwelling
organisms. EPA is still reviewing literature sources identified in the original search that suggest that the
asbestos exposure levels in sediments is low and perhaps outdated. Finally, the most important concern
for asbestos exposures are via inhalation to humans.
However, EPA does not expect to further analyze general population exposures to asbestos fibers, via
inhalation due to lofting of dried asbestos, during or after the land application of biosolids. EPA has
identified literature which indicates that asbestos has been detected in biosolids from municipal
wastewater treatment. However, it is expected that the concentration of asbestos fibers in biosolids due
to current uses of asbestos will be low, and thus the subsequent re-suspension of the asbestos fibers into
air following biosolid land application, although possible, will result in exceedingly low airborne
concentrations.
2.5.3.3	Pathways That EPA Does Not Expect to Include in the Risk Evaluation
Exposures to receptors (i.e. general population, terrestrial species) may occur from industrial and/or
commercial uses, industrial releases to air, water or land, and other conditions of use. As described in
Section 2.5, EPA does not expect to include in the risk evaluation pathways under programs of other
environmental statutes, administered by EPA, which adequately assess and effectively manage
exposures and for which long-standing regulatory and analytical processes already exist. These
pathways are described below.
Air Pathway
The Clean Air Act (CAA) contains a list of hazardous air pollutants (HAP) and provides EPA with the
authority to add to that list pollutants that present, or may present, a threat of adverse human health
effects or adverse environmental effects. For stationary source categories emitting HAP, the CAA
requires issuance of technology-based standards and, if necessary additions or revisions to address
developments in practices, processes, and control technologies, and to ensure the standards adequately
protect public health and the environment. The CAA thereby provides EPA with comprehensive
authority to regulate emissions to ambient air of any hazardous air pollutant.
Asbestos is a HAP. Because stationary source releases of asbestos to ambient air are adequately assessed
and any risks effectively managed when under the jurisdiction of the CAA, EPA does not plan to
evaluate emission pathways to ambient air from commercial and industrial stationary sources or
associated inhalation exposure of the general population or terrestrial species in this TSCA evaluation.
Drinking Water Pathway
EPA has regular analytical processes to identify and evaluate drinking water contaminants of potential
regulatory concern for public water systems under the Safe Drinking Water Act (SDWA). Under
SDWA, EPA must also review and revise "as appropriate" existing drinking water regulations every 6
years.
EPA has promulgated National Primary Drinking Water Regulations (NPDWRs) for asbestos under the
Safe Drinking Water Act. EPA has set an enforceable Maximum Contaminant Level (MCL) as close as
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feasible to a health based, non-enforceable Maximum Contaminant Level Goal (MCLG). Feasibility
refers to both the ability to treat water to meet the MCL and the ability to monitor water quality at the
MCL, SDWA Section 1412(b)(4)(D), and public water systems are required to monitor for the regulated
chemical based on a standardized monitoring schedule to ensure compliance with the MCL. The MCL
for asbestos in water is 7 million fibers/liter, or 7 MFL.
Hence, because the drinking water exposure pathway for asbestos is currently addressed in the SDWA
regulatory analytical process for public water systems, EPA does not expect to include this pathway in
the risk evaluation for asbestos under TSCA.
Ambient Water Pathways
EPA develops recommended water quality criteria under section 304(a) of the CWAfor pollutants in
surface water that are protective of aquatic life or human health designated uses. EPA develops and
publishes water quality criteria based on priorities of states and others that reflect the latest scientific
knowledge. A subset of these chemicals are identified as "priority pollutants" (103 human health and 27
aquatic life). The CWA requires states adopt numeric criteria for priority pollutants for which EPA has
published recommended criteria under section 304(a), the discharge or presence of which in the affected
waters could reasonably be expected to interfere with designated uses adopted by the state. When states
adopt criteria that EPA approves as part of state's regulatory water quality standards, exposure is
considered when state permit writers determine if permit limits are needed and at what level for a
specific discharger of a pollutant to ensure protection of the designated uses of the receiving water. Once
state adopt criteria as water quality standards, the CWA requires that National Pollutant Discharge
Elimination System (NPDES) discharge permits include effluent limits as stringent as necessary to meet
standards. CWA section 301(b)(1)(C). This is the process used under the CWA to address risk to human
health and aquatic life from exposure to a pollutant in ambient waters.
EPA has identified asbestos as a priority pollutant and EPA has developed recommended water quality
criteria for protection of human health for asbestos which are available for adoption into state water
quality standards for the protection of human health and are available for use by NPDES permitting
authorities in deriving effluent limits to meet state narrative criteria. As such, EPA does not expect to
include this pathway in the risk evaluation under TSCA. EPA's Office of Water and Office of Pollution
Prevention and Toxics will continue to work together providing understanding and analysis of the CWA
water quality criteria development process and to exchange information related to toxicity of chemicals
undergoing risk evaluation under TSCA. EPA may update its CWA section 304(a) water quality criteria
for asbestos in the future under the CWA.
EPA has not developed CWA section 304(a) recommended water quality criteria for the protection of
aquatic life for asbestos, so there are no national recommended criteria for this use available for
adoption into state water quality standards and available for use in NPDES permits. As a result, this
pathway will undergo aquatic life risk evaluation under TSCA (see Section 2.5.3.1). EPA may publish
CWA section 304(a) aquatic life criteria for asbestos in the future if it is identified as a priority under the
CWA.
Disposal Pathways
Asbestos is not regulated as aRCRA hazardous waste under RCRA Subtitle C. The general RCRA
standard in RCRA section 3004(a) for the technical criteria that govern the management (treatment,
storage, and disposal) of hazardous waste are those "necessary to protect human health and the
environment." Subtitle C controls cover not only hazardous wastes that are landfilled, but also hazardous
wastes that are incinerated (subject to joint control under RCRA Subtitle C and the Clean Air Act
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(CAA) hazardous waste combustion MACT) or injected into UIC Class I hazardous waste wells (subject
to joint control under Subtitle C and the Safe Drinking Water Act (SDWA)).
EPA does not expect to include emissions to ambient air from municipal and industrial waste
incineration and energy recovery units in the risk evaluation, as they are regulated under section 129 of
the Clean Air Act. An incinerator burning hazardous waste must achieve a destruction and removal
efficiency (DRE) of 99.99% for each principal organic hazardous constituent. Furthermore, RCRA
provisions for site-specific risk assessments and the Hazardous Waste Combustor maximum achievable
control technology (MACT) rule provisions for a Residual Risk and Technology Review together cover
risks for RCRA-regulated hazardous wastes and CAA HAPs. Emissions to ambient air from municipal
and industrial waste incineration and energy recovery units will not be included in the risk evaluation, as
they are regulated under section 129 of the Clean Air Act. CAA section 129 also requires EPA to review
and, if necessary, add provisions to ensure the standards adequately protect public health and the
environment. Thus, the asbestos combustion by-products from incineration treatment of asbestos wastes
(less than 188,437 lbs identified in Table 2-4 under "treatment" which includes incineration, as well as
other treatment methods) would be subject to the aforementioned regulations.
EPA does not expect to include on-site releases to land that go to underground injection in its risk
evaluation. TRI reporting in 2015 indicated zero pounds of asbestos were released to underground
injection to a Class I well. Therefore, disposal of asbestos via underground injection will not result in
environmental and general population exposures.
EPA does not expect to include on-site releases to land that go to RCRA Subtitle C hazardous waste
landfills or RCRA Subtitle D municipal solid waste (MSW) landfills or exposures of the general
population (including susceptible populations) or terrestrial species from such releases in the TSCA risk
evaluation. Based on 2015 reporting to TRI, approximately 38% of the land disposals of asbestos occur
in Subtitle C landfills (9.7 million lbs) as opposed to all other land disposal (15.8 million pounds).
Design standards for Subtitle C landfills require double liner, double leachate collection and removal
systems, leak detection system, run on, runoff, and wind dispersal controls, and a construction quality
assurance program. They are also subject to closure and post-closure care requirements including
installing and maintaining a final cover, continuing operation of the leachate collection and removal
system until leachate is no longer detected, maintaining and monitoring the leak detection and
groundwater monitoring system. Bulk liquids may not be disposed in Subtitle C landfills. Subtitle C
landfill operators are required to implement an analysis and testing program to ensure adequate
knowledge of waste being managed, and to train personnel on routine and emergency operations at the
facility. Hazardous waste being disposed in Subtitle C landfills must also meet RCRA waste treatment
standards before disposal. In addition, landfills have special requirements for handling and securing the
asbestos-containing waste regulated under NESHAP to prevent releases of asbestos into the air.
NESHAP requires that regulated asbestos-containing waste material be sealed in a leak-tight container
while wet, labeled, and disposed of properly in a landfill qualified to receive asbestos waste. Landfills
have special requirements for handling and securing the asbestos containing waste to prevent releases of
asbestos into the air. Transportation vehicles that move the waste from the point of generation to the
asbestos landfill have special labeling requirements and waste shipment recordkeeping requirements.
Finally, asbestos is a fiber that is not likely to be leached out of a landfill. Given these controls, general
population exposure to asbestos in groundwater from Subtitle C landfill leachate is not expected to be a
significant pathway.
While permitted and managed by the individual states, municipal solid waste (MSW) landfills are
required by federal regulations to implement some of the same requirements as Subtitle C landfills.
MSW landfills generally must have a liner system with leachate collection and conduct groundwater
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monitoring and corrective action when releases are detected. MSW landfills are also subject to closure
and post-closure care requirements, and must have financial assurance for funding of any needed
corrective actions. MSW landfills have also been designed to allow for the small amounts of hazardous
waste generated by households and very small quantity waste generators (less than 220 lbs per month).
EPA does not expect to include on-site releases to land from RCRA Subtitle C hazardous waste landfills
orRCRA Subtitle D municipal solid waste landfills or exposures of the general population (including
susceptible populations) or terrestrial species in this TSCA evaluation.
Industrial-non-hazardous and construction/demolition waste landfills are primarily regulated under state
regulatory programs. States must also implement limited federal regulatory requirements for siting,
groundwater monitoring, and corrective action, and a prohibition on open dumping and disposal of bulk
liquids. States may establish additional requirements such as for liners, post-closure care and financial
assurance, but are not required to do so. Therefore, EPA does not expect to include this pathway in the
risk evaluation.
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RELEASES AND WASTES FROM
INDUSTRIAL/COMMERCIAL/
CONSUMER USES
EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORS
HAZARDS
Wastewater,
other liquid
wastes 8

Industrial Pre-
Treatment or
•ndustr'a'WWT


TtdjrecJd.!schaf"ge

POTW
r
Direct
d'schsrg*
\
^ Aquatic
' v Species
Hazards PotentiallyAssociated with
Asbestos Exposure
See Section 2.4,1
Soil
Inhalation

KEY
Med^a'Receptors*h9t w 1 not be further ans'-yced
-¥¦ Pattuvavthat* 1 fcenjithef ansyzed
P&thwa^that'.v1 .notbe'intherana v^ed
Figure 2-4. Asbestos Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards
aIndustrial wastewater or liquid wastes may be treated on-site and then released to surface water (direct discharge), or pre-treated and released
toPOTW (indirect discharge). For consumer uses, such wastes may be released directly toPOTW (i.e. down the drain).
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2.6 Analysis Plan
The analysis plan presented here elaborates on the initial analysis plan that was published in the Scope of
the Risk Evaluation for Asbestos (	).
The analysis plan is based on the conditions of use of asbestos, as described in Section 2.2 of this
problem formulation. EPA is implementing systematic review approaches to identify, select, assess,
integrate and summarize the findings of studies supporting the TSCA risk evaluation. The analytical
approaches and considerations in the analysis plan are used to frame the scope of the systematic review
activities for that assessment. The supplemental document, Application of Systematic Review in TSCA
Risk Evaluations (	?018), provides additional information about criteria and methods that
have been and will be applied to the first 10 chemical risk evaluations.
While EPA has conducted a comprehensive search for reasonably available information from public
sources as described in the Scope of the Risk Evaluation for Asbestos (	), EPA
encourages submission of additional existing data, such as lull study reports or workplace monitoring
from industry sources, that may be relevant for refining conditions of use, exposures, hazards and
potentially exposed or susceptible subpopulations during the risk evaluation. EPA will continue to
consider new information submitted by the public.
During risk evaluation, EPA will rely on the comprehensive literature results (see Asbestos (CASRN
1332-21-4) Bibliography: Supplemental File for the TSCA Scope Document, EPA-HQ-OPPT-^
0736) or supplemental literature searches to address specific questions. Further, EPA may consider any
relevant confidential business information (CBI) in the risk evaluation in a manner that protects the
confidentiality of the information from public disclosure. The analysis plan is based on EPA's
knowledge of asbestos to date which includes partial, but not complete review of identified literature.
Should additional data or approaches become available, EPA may refine its analysis plan based on this
information.
2.6.1 Exposure
Based on their physical-chemical properties, expected sources, and transport and transformation within
the outdoor and indoor environment chemical substances are more likely to be present in some media
and less likely to be present in others. Media-specific levels will vary based on the chemical substance
of interest. For most chemical substances level(s) can be characterized through a combination of
available monitoring data and modeling approaches.
2.6.1.1 Environmental Fate and Environmental Releases
In the scope document, there was a section in the analysis plan pertaining to environmental fate. Most
questions originally posed were determined to be not relevant for asbestos, a naturally occurring and
solid material, during problem formulation.
As described in Section 2.5, EPA does not expect to further analyze certain releases to environmental
media. However, for purposes of developing estimates of occupational exposure, EPA may use release
related data collected under selected data sources such as the Toxics Release Inventory (TRI) and
National Emissions Inventory (NEI) programs.
EPA expects to consider and analyze releases to environmental media as follows:
1) Review reasonably available published literature or information on processes associated with the
conditions of use to evaluate the types of releases and wastes generated from ongoing uses.
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• EPA has received and continues to receive measured data from some of the
industries, and these data will be reviewed and used in the risk evaluation, where
appropriate. These documents can be found at:
September 6, 2017, Asbestos Use Outreach Meeting Between EPA, Occidental Chemical
Corporation and the American Chemistry Council (ACC)
https://www.regtd,iiit«its.gov/documer> t PA-HQ-OPPT-2016-Q736-Q * s
September 14, 2017, Asbestos Use Outreach Meeting Between EPA, Olin Chemical and
the American Chemistry Council (ACC)
fattp s y/www.re gulatio ns. gov/doc time i ^ ' 11—s. i' \ k )-OPPT-2016-Q736-0117
October 20, 2017, Asbestos Use Outreach Teleconference Between EPA and American
Friction
fattp s y/www. re gulatio ns. gov/docume nt 'U I !_\J )-QPPT-2016-0736-01 Us
October 30, 2017, Asbestos Use Outreach Meeting Between EPA, Chemours, Branham
Corp. and the American Chemistry Council (ACC)
fattps://www.regulations.gov/documen> '\^J ^ )-QPPT-2016-0736-01
2) Review reasonably available release data on asbestos, including measured or estimated release data
(e.g., data collected under the TRI and National Emissions Inventory [NEI] programs and Office of
Water, and Office of Land and Emergency Management, etc.).
•	The Office of Water provided OPPT with surface water data and a preliminary review
shows some samples in receiving waters have reported asbestos concentrations ranging
from 1-14 million fibers per liter (MFL).
•	Review site specific treatment information for possible development of site specific
release model.
•	Review the release assessment approaches developed for 1988 Asbestos Ban and Phase-
Out rule and, if possible, make any needed modifications or updates to models and
exposure parameters used in ABPO.
2.6.1.2 Environmental Exposures
EPA expects to consider the following in developing its Environmental Exposure Assessment of
asbestos:
1)	Review reasonably available environmental and biological monitoring data for release water
(ecological receptors only).
•	Based on the discussions in Sections 2.2 through 2.5, EPA will be focusing on the
possible presence of asbestos in water for aquatic organisms.
2)	Review reasonably available information on releases near industrial point sources (e.g. asbestos
releases from chlor-alkali manufacture) compare with available monitoring data. Available exposure
models will be evaluated and considered alongside available monitoring data to characterize
environmental exposures to water for ecological receptors. The following sources of data could be
consulted:
•	Some information has been evaluated (OW six-year review as cited above) and others
(listed below) will be further analyzed.
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¦ STORET (USGS/EPS) for chemicals in surface water and sediment:
https://www.epa.gov/waterdata/storage-aiid-retrieval-and-water-qiialitY-
exchange#portal
3)	Review 1989 Asbestos Ban and Phase Out (ABPO) support documents (i.e. exposure assessment,
risk assessment documents) to inform approaches for air modeling and general population
exposures for asbestos-containing products. Evaluate more recent modeling approaches for and
review secondary sources of data (e.g., ATSDR).
4)	Evaluate the weight of evidence of environmental occurrence data and modeled estimates.
5)	Continue to map or group each condition(s) of use to environmental assessment scenario(s).
2.6.1.3 Occupational Exposures
EPA expects to consider and analyze both worker and occupational non-user exposures as follows:
1)	Review reasonably available worker exposure monitoring data for specific conditions) ofuse(i.e.,
personal and area samples from chlor-alkali industry, users of asbestos-containing sheet gaskets,
OSHA, NIOSHand other data received by EPA and found in published literature).
•	Information provided during meetings with the chlor-alkali industry, written correspondence
from the American Chemistry Council (ACC), site visits to chlor-alkali plants will be
reviewed and used by EPA in exposure scenarios;
•	Information provided by chemical industry representatives along with an importer/supplier
of asbestos-containing sheet gaskets who further fabricate the sheet gaskets for use in
equipment for the manufacture of titanium dioxide will be used by EPA in exposure
scenarios.
•	Identify additional information on imported asbestos brake blocks used in the oil industry to
define exposure scenarios.
•	Received personal monitoring and area sampling from OSHA.
2)	Review process information, including use of personal protective equipment and engineering
controls, from the chlor-alkali industry and users of asbestos-containing sheet gaskets (an effort
currently underway), to better characterize work practices and exposures in occupational settings.
•	Review information on PPE use received from chlor-alkali industry;
•	Review information on PPE use received from gasket fabricators
•	Obtain PPE and exposure data for workers from use of oil brake blocks.
3)	For conditions of use where information is limited or not available, review existing exposure
models that may be applicable.
•	Review 1988 Asbestos Ban and Phase Out (ABPO) rule support documents to inform
approaches for workplace exposure modeling.
•	Evaluate current models and exposure assessment approaches for workplace air modeling
(e.g., AERMOD, EFAST).
•	EPA is continuing to review the literature to identify exposure scenarios corresponding to
some of the conditions of use, such as other gaskets and packing and woven products. EPA
will continue to look for reasonably available information to understand those conditions of
use which may inform exposure scenarios. EPA may also need to further research applicable
models that may be used to estimate releases for certain conditions of use.
4)	Incorporate applicable engineering controls and/or personal protective equipment into exposure
scenarios, as appropriate.
5)	Evaluate the weight of the evidence of occupational exposure data.
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6) Use the Table provided in Appendix C, which maps and groups each condition of use to
occupational exposure assessment scenario(s), to develop, adapt, or apply exposure models or
empirical data to the risk evaluation.
2.6.1.4 Consumer Exposures
As noted in Section 2.2, the consumer products being considered are imported asbestos-containing
woven products and imported asbestos brakes/linings. EPA expects to consider and analyze both
consumers using a consumer product and bystanders who are nearby as follows:
1)	Define exposure scenarios for consumers by considering sources of exposure (consumer products),
exposure pathways, exposure settings, exposure routes, and populations exposed. Considerations
for constructing exposure scenarios for consumers include:
•	Given that the consumer exposure scenarios are limited to 2 categories of uses and that
very little information has been identified to date on the extent of the uses, EPA will
attempt to communicate with identified importers of asbestos-containing products
(automotive brakes and woven products) to determine current status of import and use
•	Identify reasonably available data on consumer products or products available for
consumer use including the content of asbestos in products
•	Identify information characterizing the use patterns of consumer products containing
asbestos including how the product is used, the amount of product used, frequency and
duration of use, and room of use
•	Identify the associated exposure setting and route of exposure for consumers
•	Review reasonably available population- or subpopulation-specific exposure factors and
activity patterns to determine if potentially exposed or susceptible subpopulations need
be further refined. Populations who may be exposed to products, including potentially
exposed and susceptible subpopulations such as children or women of child bearing age,
consumers and bystanders of uses of existing asbestos products including subsets of
consumers who may use commercially available asbestos-containing products more
frequently. For exposure pathways where data are not available, review existing indoor
and outdoor exposure models that may be applicable in estimating exposure levels.
Determine the applicability of the identified models for use in a quantitative exposure
assessment.
2)	Use the Table provided in Appendix C, which maps and groups each condition of use to consumer
exposure assessment scenario(s), to develop, adapt, or apply exposure models or empirical data to
the risk evaluation.
3)	Evaluate the weight of evidence of consumer exposure data.
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2.6.2 Hazards (Effects)
2.6.2.1	Environmental Hazards
EPA expects to consider and analyze environmental hazards of asbestos as follows:
1)	Review reasonably available environmental hazard data.
•	Environmental hazard studies were identified using the literature search strategies laid
out in the "Strategy for Conducting Literature Searches for Asbestos: Supplemental
Document to the TSCA Scope Document (CASRN1332-21-4)". Section 2.4.1 provides a
summary of the appropriate environmental hazard data.
•	As discussed in Section 2.5.3.1, only aquatic ecological receptors were identified as being
evaluated further for this risk evaluation.
2)	Conduct hazard identification (the qualitative process of identifying acute and chronic
endpoints) and concentration-response assessment (the quantitative relationship between hazard
and exposure) for all identified environmental hazard endpoints.
•	There are aquatic (aqueous-only) studies identified, which assess the aquatic hazard of
chronic (13-86 days) exposure to chrysotile asbestos. The chronic hazard to fish and
aquatic invertebrates exposed to asbestos is possible at concentrations ranging from 104-
108 fibers/L.
3)	Derive aquatic concentrations of concern (COC) for acute and, where possible, chronic
endpoints.
The aquatic environmental hazard studies may be used to derive acute and chronic
concentrations of concern (COC) for mortality, behavioral, developmental and
reproductive or other endpoints determined to be detrimental to environmental
populations. Depending on the robustness of the evaluated data for a particular organism
(e.g. aquatic invertebrates), environmental hazard values (e.g. ECx/LCx/NOEC/LOEC,
etc.) may be derived and used to further understand the hazard characteristics of asbestos
to aquatic species.
4)	Evaluate the weight-of-evidence of the environmental hazard data.
•	In the risk evaluation, each study will be evaluated based on its overall study confidence.
An analysis of the acute and chronic toxicity values derived from the studies may then be
used to determine a reliable range of acute and chronic toxicity thresholds to characterize
the hazard of asbestos to environmental organisms. EPA expects to consider and evaluate
the weight-of-evidence (WOE) of the aquatic (aqueous-only) environmental hazard data
by comparing and contrasting different aquatic endpoints in the literature and U.S. EPA
WOE guidance document (K _£ » >• \ A'1 4).
5)	Consider the route(s) of exposure, available environmental monitoring data and available
approaches to integrate exposure and hazard assessments.
•	The chronic hazard to fish and aquatic invertebrates exposed to asbestos is possible at
concentrations ranging from 104- 108 fibers/L; which is equivalent to 0.01 to 100 MFL
(million fibers/Liter). The Office of Water provided OPPT with surface water data and a
preliminary review shows some samples in receiving waters have reported asbestos
concentrations ranging from 1-14 MFL.
2.6.2.2	Human Health Hazards
Given the well-established carcinogenicity of asbestos for lung cancer and mesothelioma, EPA decided
to limit the scope of its systematic review to these two specific cancers with the goal of updating, or
reaffirming, the existing cancer unit risk (	88b).
EPA expects to consider and analyze human health hazards as follows:
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1)	Included human health studies will be reviewed using the evaluation strategies laid out in the
Application of Systematic Review in TSCA Risk Evaluations (	)
•	Studies will be evaluated using specific data evaluation criteria.
•	Study results will be extracted and presented in evidence tables by cancer endpoint.
2)	Evaluate the weight of the scientific evidence of human health hazard data.
•	EPA will rely on the weight of the scientific evidence when evaluating and integrating
human health hazard data. The data integration strategy will be designed to be fit-for-
purpose in which EPA will use systematic review methods to assemble the relevant data,
evaluate the data for quality and relevance, including strengths and limitations, followed
by synthesis and integration of the evidence.
•	Assess dose-response information to refine quantitative unit risk for lung cancer and
mesothelioma. Review the appropriate human data identified to update, or reaffirm, the
1988 quantitative estimate of the unit risk of asbestos-related lung cancer and
mesothelioma by the inhalation route.
3)	In evaluating reasonably available data, EPA will determine whether particular human receptor
groups may have greater susceptibility to the chemical's hazard(s) than the general population.
2.6.3 Risk Characterization
Risk characterization is an integral component of the risk assessment process for both ecological and
human health risks. EPA will derive the risk characterization in accordance with EPA's Risk
Characterization Handbook (	). As defined in EPA's J	icy, "the
risk characterization integrates information from the preceding components of the risk evaluation and
synthesizes an overall conclusion about risk that is complete, informative and useful for decision
makers." Risk characterization is considered to be a conscious and deliberate process to bring all
important considerations about risk, not only the likelihood of the risk but also the strengths and
limitations of the assessment, and a description of how others have assessed the risk into an integrated
picture.
Risk characterization at EPA assumes different levels of complexity depending on the nature of the risk
assessment being characterized. The level of information contained in each risk characterization varies
according to the type of assessment for which the characterization is written. Regardless of the level of
complexity or information, the risk characterization for TSCA risk evaluations will be prepared in a
manner that is transparent, clear, consistent, and reasonable (TCCR) (	2000). EPA will also
present information in this section consistent with approaches described in the Procedures for Chemical
Risk Evaluation Under the Amended Toxic Substances Control Act (i	16). For instance, in the
risk characterization summary, EPA will further carry out the obligations under TSCA section 26; for
example, by identifying and assessing uncertainty and variability in each step of the risk evaluation,
discussing considerations of data quality such as the reliability, relevance and whether the methods
utilized were reasonable and consistent, explaining any assumptions used, and discussing information
generated from independent peer review. EPA will also be guided by EPA's Information Quality
Guidelines (	) as it provides guidance for presenting risk information. Consistent with
those guidelines, in the risk characterization, EPA will also identify: (1) Each population addressed by
an estimate of applicable risk effects; (2) the expected risk or central estimate of risk for the potentially
exposed or susceptible subpopulations affected; (3) each appropriate upper-bound or lower bound
estimate of risk; (4) each significant uncertainty identified in the process of the assessment of risk effects
and the studies that would assist in resolving the uncertainty; and (5) peer reviewed studies known to the
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Agency that support, are directly relevant to, or fail to support any estimate of risk effects and the
methodology used to reconcile inconsistencies in the scientific information.
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APPENDICES
Appendix A REGULATORY HISTORY
A-l Federal Laws and Regulations
The federal laws and regulations applicable to asbestos are listed along with the regulating agencies
below. States also regulate asbestos through state laws and regulations, which are also listed within this
section.
Toxics Substances Control Act (TSCA), 1976
The Toxic Substances Control Act of 1976 provides EPA with authority to require reporting, record-
keeping and testing requirements, and restrictions relating to chemical substances and/or mixtures.
Certain substances are generally excluded from TSCA, including, among others, food, drugs, cosmetics
and pesticides.
TSCA addresses the production, importation, use and disposal of specific chemicals including
potychtorimated biphertyls (PCBsl asbestos, radon and lead-based paint. The Frank R. Lautenberg
Chemical Safety for the 21st Century Act updated TSCA in 2016 https://www.epa. gov/taws-
leuibnons/stmihuu'i to\ie-substances control net
Asbestos Hazard Emergency Response Act (AHERA), 1986
TSCA. Subchapter SI \sbestos Hazard Emergency Response 1 > S I y2641-2656
•	Defines asbestos as the asbestiform varieties of— chrysotile (serpentine), crocidolite
(riebeckite), amosite (cummingtonite-grunerite), anthophyllite, tremolite or actinolite.
•	Requires local education agencies (i.e., school districts) to inspect school buildings for
asbestos and submit asbestos management plans to appropriate state; management plans must
be publicly available and inspectors must be trained and accredited.
•	Tasked EPA to develop an asbestos Model Accreditation Plan (MAP) for states to establish
training requirements for asbestos professionals who do work in school buildings and also
public and commercial buildings.
Asbestos-Containing Materials in Schools Rule (per AHERA), 1987
40 CFRPart 763., Subp
•	Requires local education agencies to use trained and accredited asbestos professionals to
identify and manage asbestos-containing building material and perform asbestos response
actions (abatements) in school buildings.
1989 Asbestos: Manufacture, Importation, Processing, and Distribution in Commerce
Prohibitions; Final Rule (also known as Asbestos Ban and Phase-out Rule (Remanded), 1989)
40 CFRPart 763, Subpart I
Docket in t >r \\ 6204gI TRl ^ -9-8
•	EPA issued a final rule under Section 6 of Toxic Substances Control Act (TSCA) banning
most asbestos-containing products.
•	In 1991, this rule was vacated and remanded by the Fifth Circuit Court of Appeals. As a
result, most of the original ban on the manufacture, importation, processing or distribution in
commerce for the majority of the asbestos-containing products originally covered in the 1989
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final rule was overturned. The following products remain banned by rule under the Toxic
Substances Control Act (TSCA):
o Corrugated paper
o Rollboard
o Commercial paper
o Specialty paper
o Flooring felt
In addition, the regulation continues to ban the use of asbestos in products that have not historically
contained asbestos, otherwise referred to as "new uses" of asbestos (Defined by 40 CFR 763.163 as
"commercial uses of asbestos not identified in §763.165 the manufacture, importation or processing of
which would be initiated for the first time after August 25, 1989.").
Other EPA Regulations:
Asbestos Worker Protection Rule, 2000
40 CFR Part 763, Subp
•	Extends OSHA standards to public employees in states that do not have an OSHA approved
worker protection plan (about half the country).
Asbestos Information Act, 1988
15 11 S (' 32607(f)
•	Helped to provide transparency and identify the companies making certain types of asbestos-
containing products by requiring manufacturers to report production to the EPA.
Asbestos School Hazard Abatement Act (ASHAA), 1984 and Asbestos School Hazard Abatement
Reauthorization Act (ASHARA), 1990
2^ M tQl I et seq. and IW ^ H * r	:• -8
•	Provided funding tor and established an asbestos abatement loan and grant program for
school districts and ASHARA further tasked EPA to update the MAP asbestos worker
training requirements.
Emergency Planning and Community Right-to-Know Act (EPCRA), 1986
42 U.S.C. Chapter
•	Under Section 313, Toxics Release Inventory (TRI), requires reporting of environmental
releases of friable asbestos at a concentration level of 0.1%.
•	Friable asbestos is designated as a hazardous substance subject to an Emergency Release
Notification at 40 CFR §355.40 with a reportable quantity of 1 pound.
Clean Air Act, 1970
seq.
•	Asbestos is identified as a Hazardous Air Pollutant.
Asbestos National Emission Standard for Hazardous Air Pollutants (NESHAP), 1973
40 CFR.	bpart M of the Clean Air Act
•	Specifies demolition and renovation work practices involving asbestos in buildings and other
facilities (but excluding residences with 4 or fewer dwelling units single family homes).
•	Requires building owner/operator notify appropriate state agency of potential asbestos hazard
prior to demolition/renovation.
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•	Banned spray-applied surfacing asbestos-containing material for fireproofing/insulating
purposes in certain applications.
•	Requires that asbestos-containing waste material from regulated activities be sealed in a leak-
tight container while wet, labeled, and disposed of properly in a landfill qualified to receive
asbestos waste.
Clean Water Act (CWA), 1972
1 -S-C. *$1251 et scq
•	Toxic pollutant subject to effluent limitations per Section 1317.
Safe Drinking Water Act (SDWA), 1974
300f
•	Asbestos Maximum Contaminant Level Goals (MCLG) 7 million fibers/L (longer than
lOum).
Resource Conservation and Recovery Act (RCRA), 1976
1 ( _ 5°0"1 ct seq.
40 CFR 239-282
•	Asbestos is subject to solid waste regulation when discarded; NOT considered a hazardous
waste.
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), 1980
nation of Hazardous Substances and Reportable Quantities
•	13 Superfund sites containing asbestos, nine of which are on the National Priorities List
(NPL)
•	Reportable quantity of friable asbestos is one pound.
Other Federal Agencies:
Occupational Safety and Health Administration (OSHA):
Public i j\v 0 l -gy» Occupational Safety and Health Act, 1970
Employee permissible exposure limit (PEL) is 0.1 fibers per cubic centimeter (free) as an 8-hour, time-
weighted average (TWA) and/or the excursion limit (1.0 free asa30-minute TWA).
•	Asbestos General Standard 29 CFR 1
•	Asbestos Shipyard Standard 29 CFR
•	Asbestos Construction Standard 29 C 26
Consumer Product Safety Commission (CPSC): Banned several consumer products. Federal Hazardous
Substances Act (FHSA)
Food and Drug Administration (FDA): Prohibits the use of asbestos-containing filters in pharmaceutical
manufacturing, processing and packing. 21 CFR 211.72
Mine Safety and Health Administration (MSHA): follows OSHA's safety standards.
Surface Mines JO 1 H< thui V nthtxin D
Underground Mines
Department of Transportation
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Prescribes the requirements for shipping manifests and transport vehicle placarding applicable to
asbestos 40 wrt 1 H.
Non-regulatory information of note:
• NIOSH conducts related research and monitors asbestos exposure through workplace
activities in an effort to reduce illness and ensure worker health and safety.
A-2 State Laws and Regulations
Pursuant to AHERA, states have adopted through state regulation the EPA's Model Accreditation Plan
(MAP) for asbestos abatement professionals who do work in schools and public and commercial
buildings. . Thirty-nine (39) states6 have EPA-approved MAP programs and twelve (12) states7 have
also applied to and received a waiver from EPA to oversee implementation of the Asbestos-Containing
Materials in Schools Rule pursuant to AHERA. States also implement regulations pursuant to the
Asbestos NESHAP regulations or further delegate those oversight responsibilities to local municipal
governments. While federal regulations set national asbestos safety standards, states have the authority
to impose stricter regulations. As an example, many states extend asbestos federal regulations - such as
asbestos remediation by trained and accredited professionals, demolition notification, and asbestos
disposal - to ensure safety in single-family homes. Thirty (30) states8 require firms hired to abate
asbestos in single family homes to be licensed by the state. Nine (9) states9 mandate a combination of
notifications to the state, asbestos inspections, or proper removal of asbestos in single family homes.
Some states have regulations completely independent of the federal regulations. For example, California
and Washington regulate products containing asbestos. Both prohibit use of more than 0.1% of asbestos
in brake pads and require laboratory testing and labeling.
Below is a list of state regulations that are independent of the federal AHERA and NESHAP
requirements that states implement. This may not be an exhaustive list.
California
Asbestos is listed on California's Candidate Chemical List as a carcinogen. Under California's
Propositions 65, businesses are required to warn Californians of the presence and danger of asbestos in
products, home, workplace and environment.
California Brake Friction Material Requirements (Effective 2017)
Division > >>wuia Code of Regulations, Title 22 Chapter
Sale of any motor vehicle brake friction materials containing more than 0.1% asbestiform fibers by
weight is prohibited. All brake pads for sale in the state of California must be laboratory tested, certified
and labeled by the manufacturer.
6	Alabama, Alaska, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Illinois, Indiana, Kentucky, Louisiana,
Maine, Maryland, Massachusetts,Michigan, Minnesota,Mississippi,Missouri, Montana,Nebraska, New Hampshire, New
Jersey, New York, North Carolina, North Dakota, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South
Dakota, Texas, Utah, Vermont, Virginia, Washington, West Virginia, and Wisconsin.
7	Connecticut, Colorado, Illinois, Kentucky, Louisiana, Massachusetts,Maine, New Hampshire, Oklahoma, Rhode Island,
Texas, and Utah.
8	California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Iowa, Kansas,Maine, Maryland, Massachusetts,
Michigan, Minnesota,Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North
Dakota, Oregon, Pennsylvania, Utah, Vermont, Virginia, Washington, West Virginia, and Wisconsin.
9	Colorado, Connecticut, Georgia, Maine, Massachusetts, New York, Oregon, Vermont, and West Virginia.
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Massachusetts
Massach'tv > ¦> Toxics Use Reduction Act (IT AO
Requires companies in Massachusetts to provide annual pollution reports and to evaluate and implement
pollution prevention plans. Asbestos is included on the	meals -March
2016.
Minnesota
Toxic Free Kids Act \'i> > » , A' > j ' > >' > t t '
Asbestos is included on the	List as a known carcinogen.
New Jersey
New Jersey Right to Know Hazardous Substances
The state of New Jersey identifies hazardous chemicals and products. Asbestos is listed as a known
carcinogen and talc containing asbestos is identified on the Right to Know Hazardous Substances list.
Rhode Island
Rhode Island Air Resources - /> h \h	>'..•¦"> '< » >»< «'< , \V, y.> ¦ >it Ai-. ?2
Establishes acceptable ambient air levels for asbestos.
Washington
Better Brakes Law (Effective 2015) Chapter 70.285 RCW Brake Friction Material
Prohibits the sale of brake pads containing more than 0.1% asbestiform fibers (by weight) in the state of
Washington and requires manufacturer certification and package/product labelling.
Requirement to Label Building Materials that Contain Asbestos Chapter 70.310 RCW
Building materials that contain asbestos must be clearly labeled as such by manufacturers, wholesalers,
and distributors.
A-3 International Laws and Regulations
Asbestos is also regulated internationally. Nearly 60 nations have some sort of asbestos ban. The
European Union (EU) will prohibit the use of asbestos in the chlor-alkali industry by 2025 (Regulation
(EC) No 1907/2006 of the European Parliament and of the Council, 18 December 2006).
Canada has proposed a rule to ban asbestos and regulate asbestos-containing products (Prohibition, of
Asbestos and Asbestos Products Regulations).
In addition, the Rotterdam Convention is considering adding ciirvsoni-' to Xiiiicx III, and the World
Health Organization (WHO) has a global campaign to eliminate asbestos-related diseases (WHO
Resolution 60 lb).
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Appendix B PROCESS, RELEASE AND OCCUPATIONAL
EXPOSURE INFORMATION
This appendix provides information and data found in preliminary data gathering for asbestos.
B-l Process Information
Process-related information potentially relevant to the risk evaluation may include process diagrams,
descriptions and equipment. Such information may inform potential release sources and worker
exposure activities for consideration.
B-l-1 Manufacture and Import
B-l-1-1 Manufacturing
As a naturally occurring mineral, asbestos is manufactured by mining, but asbestos has not been mined
(or manufactured) in the United States since 2002 (USGS, ).
15-1-1-2 Import
All asbestos used in this country is imported. According to the U.S. Geological Survey (USGS), the only
form of asbestos currently imported into the United States is chrysotile, all of which originated from
Brazil in 2017 (USGS, 2018). USGS reports that in 2017, the United States imported approximately 300
metric tons of raw asbestos, the total of which they state is used in the chlor-alkali industry ("" ""
2018). In 2016, the United States imported approximately 702 metric tons of raw asbestos (r
2017). According to chlor-alkali industry information, chrysotile asbestos used in the fabrication of
diaphragms is imported in sealed containers, with the asbestos in 40-50 kg sealed bags made of dust-
proof^ woven plastic. Typically, they indicated that 20 bags are placed on a pallet at the point of
shipment and the pallet is covered completely by a heavyweight wrap - durable and similar in thickness
to a drum liner. The pallets are placed in a shipping container, which gets sealed with a heavy-duty bolt-
type seal. At the port of entry, the shipping container is marked and transported to a chlor-alkali facility
where the pallets and bags are removed.
B-l-2 Processing
B-l-2-1 Chlor-Alkali Industry
Asbestos (raw chrysotile) is used in the chlor-alkali industry for the fabrication of semi-permeable
diaphragms, which effectively separate the anode from the cathode chemicals in the production of
chorine and sodium hydroxide (caustic soda) (USGS, 2 ) The information in this section was
described by industry representatives to EPA in a January 2017 meeting, provided to EPA by the
American Chemistry Council (ACC) in written communication, or observed during March 2017 EPA
visits to chlor-alkali plants. The information provided below is primarily based on information provided
by either the chlor-alkali industry or ACC and is meant to represent typical practices.
Chlor-alkali industry representatives have stated that in the United States, there are three companies who
own a total of 15 chlor-alkali plants that continue to fabricate and use asbestos-containing semi-
permeable diaphragms onsite. From its entry into a port in the United States to its ultimate disposal, the
management of asbestos in the chlor-alkali industry is typically managed in a closely controlled process.
The ACC reports that engineering controls, personal protective equipment (PPE), employee training,
medical surveillance and personal monitoring are all used to monitor and mitigate worker exposures.
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After arriving at the plant, the shipping container is inspected and damaged containers are rejected.
According to industry, where containers are damaged, port/warehouse remediation activities are
managed in conformance with OSHA's asbestos standard for general industry (29 CFR 1910.1001).
Once the container is opened, the bags are inspected. If broken bags or loose asbestos is evident, the area
is controlled to prevent accidental exposure, the bags are repaired, and the area is barricaded and treated
as an area requiring cleanup. Plastic-wrapped pallets are labeled per OSHA's hazard communication and
asbestos standards. Any loose asbestos from punctured bags inside the container is cleaned up using
high-efficiency particulate air-filtered (HEPA-filtered) vacuum cleaners or wetted with water and
cleaned up before unloading proceeds. Damaged bags are placed in appropriately labeled, heavy-duty
plastic bags or appropriately repaired. Individuals not involved in cleanup are prohibited from entering
the area until cleanup is complete. When moving the asbestos bags into storage locations, care is taken
to ensure that bags are not punctured, and personnel moving the bags wear specific PPE, including
respirators and protective clothing. Storage areas are isolated, enclosed and labeled. They are secure and
inspected on a regular basis. Any area or surface with evidence of asbestos is HEP A-vacuumed or
wetted and cleaned up by employees wearing PPE.
To create these asbestos-containing diaphragm cells, sealed bags of asbestos are placed inside a glove
box (at some plants) before being opened. They are then opened and the asbestos is transferred to a
mixing tank via a closed system maintained under vacuum. At other plants, this process is frilly
automated and enclosed; where asbestos bags are placed into a machine, opened and transferred to
mixing tanks. Empty bags are placed into closed and labeled waste containers, either through a port in
the glove box or during the automated process. The raw asbestos used to create a diaphragm is mixed
with a liquid solution of weak caustic soda and salt. A resultant chrysotile asbestos slurry is created and
asbestos is no longer likely to become airborne. Modifiers (e.g., Halar®, Teflon®) are added to the
slurry and then co-deposited in the diaphragm and heated. The modifiers fuse to the asbestos. The
amount of asbestos used for each are added to the slurry, which is then co-deposited in the diaphragm
and heated. The modifiers fuse to the asbestos. The amount of asbestos used for each diaphragm is in the
range of 50-250 lbs (depending on cell size) and atypical plant will use about 5-25 tons of raw asbestos
per year. Industry representatives stated during meetings with EPA that a standard-sized manufacturing
cell will have a surface area of 70 m2 and each cell will typically have 20 chrysotile asbestos diaphragms
within it, although cell size can vary.
The chlor-alkali chemical production process involves the separation of the sodium and chloride atoms
of salt in saltwater (brine) via electricity to produce sodium hydroxide (caustic soda), hydrogen and
chlorine. Specifically, brine is passed through an electric current and sodium hydroxide, hydrogen and
chlorine are formed. This reaction occurs in an electrolytic cell. The cell contains two compartments
separated by a semi-permeable diaphragm, which is made mostly of chrysotile asbestos. The diaphragm
prevents the reaction of the caustic soda with the chlorine and allows for the separation of both materials
for further processing.
The cell will typically operate for 1-3 years before it must be replaced due to a loss of conductivity.
Many factors can determine the life of a cell, including the brine quality and the size of the cell. In plants
where the diaphragm is replaced but the cell is reused, the asbestos is hydro-blasted out (remaining in a
wet state) in a cleaning bay. The excess water used during this process is filtered prior to discharge to
the facility's wastewater collection and treatment system. The filtered waste is to be sealed into
containers that are sent to a landfill that accepts asbestos-containing waste per federal and state asbestos
disposal regulations.
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B-l-3 Uses
B-l-3-1 Oil Industry
At least one company in the United States sefis asbestos-containing brake blocks in the oil industry. The
brake of a drawworks hoisting machine is an essential component of a rotary drilling rig, as the machine
is used to hoist or lower thousands of pounds of weight in large operations. At least one U.S. company
imports and distributes non-metallic, asbestos-woven brake blocks used in the drawworks of drilling
rigs. According to product specification sheets, asbestos-containing brake blocks are most often used on
large drilling drawworks and contain wire in the backing only for added strength, and they are more
resistant than full-metallic blocks, with good flexibility and a favorable coefficient of friction block. The
asbestos allows for heat dissipation and the woven structure provides firmness and controlled density of
the brake block. Workers in the oilfield industry operate a drilling rig's brakes in an outdoor
environment, and must periodically replace spent brake blocks.
B-l-3-2 Use of Sheet Gaskets in Titanium Dioxide Production
In the	..., ...	''ZOO- "^1	L_-r	7 •'
A she, public document [Docket	, (	)], Table 1 depicts a
"List of Asbestos-Containing Products Currently Available for Purchase on the internet." On page 11 of
the preliminary information document, EPA lists useful types of information. During the public
comment period, one chemical production company notified EPA of the current use of imported gaskets
from China (Comment ID	-0067). According to the comment, these sheet
gaskets are composed of 80% (minimum) chrysotile asbestos, fully encapsulated in Styrene Butadiene
Rubber, and used to create tight chemical containment seals during the production of titanium dioxide.
EPA learned through stakeholder meetings that these sheet gaskets are imported, processed, then
distributed in the United States.
B-1-3-3 Commercial Uses
Chrysotile asbestos has several unique properties, including low electrical conductivity, high tensile
strength, high friction coefficient and high heat resistance (Villa, 2011). These properties make asbestos
ideal for use in friction materials (brakes), insulation (sound, heat and electrical) and building materials
(cement pipes, roofing compounds, adhesives, flooring) over the past century. However, due to health
concerns and consumer preference, most products used commercially in the United States are now
asbestos-free. Although most domestically manufactured products are asbestos-free, it is possible that
imported asbestos-containing products could go into aftermarket sales and be used commercially (e.g., a
mechanic installing new brakes or construction worker installing cement pipes). Most available products
used commercially contain non-friable asbestos but can become friable during processing and use.
B-l-3-4 Consumer Uses
Remaining asbestos-containing products available for consumer use in the United States include a
limited number of imported woven products and imported aftermarket friction products (USGS, 2017).
These same products could also be used commercially. EPA staff conducted an online search using
various search terms to determine any currently available asbestos-containing products in the United
States. The products found were either advertised as containing asbestos or the associated Safety Data
Sheet (SDS) listed asbestos as a product constituent. Additionally, the EPA reviewed databases (EPA
CPCat, U.S. Department of Health and Human Services [DHHS] Household Products Database and
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DeLima Associates Consumer Product Information Database [CPID]) that list
manufacturer s/distrib uters/retailers of asbestos-containing products. Some companies found are no
longer in business or have been rebranded and absorbed by another company. In researching these
companies' products and their SDSs, EPA found little evidence of continued asbestos use. Consumer
activities using these products would likely be limited to small-scale do-it-yourself projects.
B-l-4 Disposal
Asbestos NESHAP minimizes asbestos release during renovation/demolition by requiring \LSI IAP-
regulated asbestos-containing waste material be sealed in a leak-tight container while wet, labeled and
disposed of properly in a landfill qualified to receive asbestos waste.
tos/asbestos-national-emissions-stand ard-hazardous-air-pollutants-
Transport and Disp>» it >Asbestos Waste ( Xppendix D to Subpart E of 40 CFRPart 763)
Landfills have special requirements for handling and securing the asbestos-containing waste regulated
under NESHAP to prevent releases of asbestos into the air. Transportation vehicles that move the waste
from the point of generation to the asbestos landfill have special labeling requirements and waste
shipment recordkeeping requirements(U .S. EPA, 2Q16a.)(	a)(U.S. EPA, 2016a). Specific
waste management practices are controlled at the state level.
B-2 Occupational Exposure Data
Data that inform occupational exposure assessment and which EPA expects to consider as part of the
occupational exposure assessment are the Occupational Safety and Health Administration (OSHA)
Chemical Exposure Health Data (CEHD), which are monitoring data collected during OSHA
inspections. According to OSHA asbestos standards, the employee permissible exposure limit (PEL) is
0.1 fibers per cubic centimeter (fee) as an 8-hour, time-weighted average (TWA) and/or the excursion
limit (1.0 fee asa30-minute TWA) (Asbestos General Standard 2	).
A preliminary summary of OSHA's monitoring data from 2011 to 2016 is presented in TableApx B-l.
These data represent actual exposure levels of asbestos at specific workplaces encompassing several
industry sectors and conditions of use.
Table Apx B-l. Summary of Industry Sectors with Asbestos Personal Monitoring Air Samples
Obtained from OSHA Inspections Conducted Between 2011 and 2016
North Ainoriciiii
Indus Iriiil
Cliissillciilion
Sjsicm (NAIC'S)
NAIC'S Description
22
Utilities
23
Construction
31
Manufacturing
32
Manufacturing
33
Manufacturing
42
Wholesale trade
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North AiiK'rk'iin
Indus Iriiil
(liissilK'iiliiin
Sjsicm (NAICS)
NAICS Di'M-riplion
44
Retail Irade
45
Retail trade
48
Transportation and warehousing
49
Transportation and warehousing
52
Finance and insurance
53
Real estate rental and leasing
54
Professional, scientific and technical services
56
Administrative and support and waste management and remediation services
61
Educational services
62
Health care and social assistance
71
Arts, entertainment and recreation
72
Accommodation and food services
92
Public administration
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Appendix C SUPPORTING TABLE FOR INDUSTRIAL, COMMERCIAL AND CONSUMER
ACTIVITIES AND USES FOR CONCEPTUAL MODELS
This appendix provides the rationale for inclusion and exclusion of exposure pathways for industrial, commercial and consumer activities.
TableAppendix C-l. Preliminary Rationale for Inclusion and Exclusion of Exposure Pathways for Industrial, Commercial and
Consumer Activities
Product
Ciili'^on (or
C )
I so i:\iini|)U- (or
Sulx'.iU'iion)
Ki'k'iisi' /
l'.\|»»s u re
Sci'ii.irio
l'A|)OMIIT
PillllWiN
l.\|)os II IT
Kollli'
Iti'iTplor /
I'oiHihilion1
ProjioM'ri lor
I'lirlhcr Risk
l>;ilii
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Dermal


lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed.
Installing and
Replacing Sheet
Gaskets
Air
Inhalation
Workers, ONU
Yes
The work process described in Comment
ID EPA-HQ-OPPT-2016-0736-0067
should be further evaluated.
Oral
Dermal
Workers, ONU
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed
Solid
Contact
Dermal
W orkers
Industrial
Friction
Products
Brake Blocks in Oil
Industry
Oilfield WeH
Production
Air
Inhalation
Workers, ONU
Yes
The process of replacing asbestos-
containing brake blocks will likely
generate friable airborne asbestos and will
be further evaluated.
Oral
Dermal
Workers, ONU
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed.
Solid
Contact
Dermal
W orkers
Aftermarket
Automotive
Brakes
Pas senger and Non-
passenger Vehicles
Commercial Brake
Servicing and
Consumer
Air
Inhalation
Workers, ONU,
Consumer
Yes
The process of replacing asbestos-
containing brakes will likely generate
friable airborne asbestos and will be
further evaluated.
Oral
Dermal
Workers, ONU,
Consumer
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed.
Solid
Contact
Dermal
W orkers
Cement
Products
Cement pipe
Contracting and
Masonry Work
Air
Inhalation
Workers, ONU
Yes
Based on datafrom USGS, it is possible
that asbestos cement pipe is imported and
used in the United States. Exposures to
workers will be evaluated.
Oral
Dermal
Workers, ONU
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
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Solid
Contact
Dermal
W orkers

from the oral and dermal routes will not
be assessed.
Woven
Products
Imported Textiles
Use of Heat -
Resistant Woven
Textiles
Air
Inhalation
Workers, ONU,
Consumer
Yes
Based on conversations with USGS,
knitted fabrics (woven products)
containing asbestos continue to be
imported into U.S.
Oral
Workers, ONU,
Consumer
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed.
Dermal
Solid
Contact
Dermal
W orkers
Other
gaskets and
packing
Chemical
Manufacturing
Installing and
Replacing Gaskets
Air
Inhalation
Workers, ONU
Yes
The work process described in Comment
ID EPA-HQ-OPPT-2016-0736-0067 will
be further evaluated.
Oral
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not
be assessed.
Dermal
Solid
Contact
Dermal
W orkers
Waste
Handling,
Treatment
and Disposal
Disposal of
Asbestos Waste
Worker Handling
of Wastes
Air
Inhalation
Workers, ONU
Yes
Disposal of asbestos containing
articles/wastes are placed in plastic bags
for disposal.
Air
Oral
No
Since neither oral nor dermal exposures
are expected to contribute to the risks of
lung cancer and mesothelioma, which are
the focus of the risk evaluation, exposures
from the oral and dermal routes will not be
assessed.
Air
Dermal
Solid
Contact
Dermal
W orkers
Liquid
Contact
Dermal
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Appendix D INCLUSION AND EXCLUSION CRITERIA FOR FULL
TEXT SCREENING
Appendix D contains the eligibility criteria for various data streams informing the TSCA risk evaluation:
environmental fate; engineering and occupational exposure; exposure to the general population and
consumers; and human health hazard. The criteria are applied to the on-topic references that were
identified following title and abstract screening of the comprehensive search results published on June 22,
2017.
Systematic reviews typically describe the study eligibility criteria in the form of PECO statements or a
modified framework. PECO stands for Population, Exposure, Comparator and Outcome and the approach is
used to formulate explicit and detailed criteria about those characteristics in the publication that should be
present in order to be eligible for inclusion in the review. EPA/OPPT adopted the PECO approach to guide
the inclusion/exclusion decisions during lull text screening.
Inclusion and exclusion criteria were also used during the title and abstract screening, and documentation
about the criteria can be found in the Strategy for Conducting Literature Searches document published in
June 2017 along with each of the TSCA Scope documents. The list of on-topic references resulting from
the title and abstract screening is undergoing lull text screening using the criteria in the PECO statements.
The overall objective of the screening process is to select the most relevant and highest quality evidence for
the TSCA risk evaluation. As a general rule, EPA is excluding non-English data/information sources and
will translate on a case by case basis.
The inclusion and exclusion criteria for ecotoxicological data have been documented in the ECOTOX
SOPs. The criteria can be found at https://cfpub.epa. gov/ecotox/hetp.cfrn?helptab s=tab4) and in the
Strategy for Conducting Literature Searches document published along with each of the TSCA Scope
documents.
Since full text screening commenced right after the publication of the TSCA Scope document, the criteria
were set to be broad to capture relevant information that would support the initial scope. Thus, the inclusion
and exclusion criteria for full text screening do not reflect the refinements to the conceptual model and
analysis plan resulting from problem formulation. As part of the iterative process, EPA is in the process of
refining the results of the full text screening to incorporate the changes in information/data needs to support
the revised scope.
These refinements will include changes to the inclusion and exclusion criteria discussed in this appendix to
better reflect the revised scope of the risk evaluation and will likely reduce the number of data/information
sources that will undergo evaluation.
D-l Inclusion Criteria for Data Sources Reporting Environmental Fate
Data
EPA/OPPT developed a generic Pathways and Processes, Exposure, Setting or Scenario, and Outcomes
(PESO) statement to guide the full text screening of environmental fate data sources. Subsequent versions
of the PESO statement may be produced throughout the process of screening and evaluating data for the
chemicals undergoing TSCA risk evaluation. Studies that comply with the inclusion criteria in the PESO
statement are eligible for inclusion, considered for evaluation, and possibly included in the environmental
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fate assessment. On the other hand, data sources are excluded if they do not meet the criteria in the PESO
statement.
Assessors seek information on various chemical-specific fate endpoints and associated fate processes,
environmental media and exposure pathways as part of the process of developing the environmental fate
assessment (TableApx D-1. Inclusion Criteria for Data Sources Reporting Environmental Fate Data). The
PESO statement and information in Table Apx D-2. Fate Endpoints and Associated Processes, Media and
Exposure Pathways Considered in the Development of the Environmental Fate Assessment) will be used
when screening the fate data sources to ensure complete coverage of the processes, pathways and data
relevant to the fate of the chemical substance of interest.
Since lull text screening commenced right after the publication of the TSCA Scope document, the criteria
for fate data were set to be broad to capture relevant information that would support the initial scope. Thus,
the inclusion and exclusion criteria for lull text screening do not reflect the refinements to the conceptual
model and analysis plan resulting from problem formulation. As part of the iterative process, EPA is in the
process of refining the results of the lull text screening to incorporate the changes in information/data needs
to support the revised scope.
Table Apx D-1. Inclusion Criteria for Data Sources Reporting Environmental Fate Data
PIISO
Kleinenl
Kvidence
Pathways
and
Processes
•	Fate will use transport, partitioning and degradation behavior across media
to inform exposure pathways in conceptual models
•	Exposure pathways included in the conceptual models:
Water
- Air
•	Processes associated with the target exposure pathways
Exposure
•	Exposures of aquatic organisms to Asbestos
•	Consumer exposure pathways of humans to Asbestos
(Chemical-specific population[s] of interest may be determined by toxicologists
or by EPA policy decisions)
Setting or
Scenario
•	All aquatic ecological exposure scenarios for releases of Asbestos to
the natural or built environment.
•	Consumer exposure scenarios of humans to Asbestos
(Chemical-specific scenarios will be determined in conjunction with
toxicologists and exposure assessors or by EPA policy decisions)
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Pl.SO
Klcmcnl
Kvidence
Outcomes
• Fate properties which allow assessments of exposure pathways:
o Partitioning within and between environmental media (see
Pathways)
TableApx D-2. Fate Endpoints and Associated Processes, Media and Exposure Pathways
Considered in the Development of the Environmental Fate Assessment
Fate Data Fndpoint
Associated Processes)
Associated Media/Kxposure Pathways
Surface
water
Soil,
Biosolids
Ground-
water
Air
[Indoor
environment,
anthropogenic
materials]
First Her Environmental
Fate Data






Particle Transport
Mobility
X


X
X
Suspension/Resuspension
Suspension/Resuspension,
Mobility
X




Water and wastewater
treatment removal
Wastewater treatment
X




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D-2 Inclusion Criteria for Data Sources Reporting Engineering and
Occupational Exposure Data
EPA/OPPT developed a generic RESO statement to guide the lull text screening of engineering and
occupational exposure literature (TableApx D-3. Inclusion Criteria for Data Sources Reporting
Engineering and Occupational Exposure Data for Asbestos). RESO stands for Receptors, Exposure, Setting
or Scenario, and Outcomes. Subsequent versions of the RESO statement may be produced throughout the
process of screening and evaluating data for the chemicals undergoing TSCA risk evaluation. Studies that
comply with the inclusion criteria specified in the RESO statement will be eligible for inclusion, considered
for evaluation, and possibly included in the environmental release and occupational exposure assessments,
while those that do not meet these criteria will be excluded.
The RESO statement should be used along with the engineering and occupational exposure data needs table
(Error! Reference source not found.) when screening the literature.
Since lull text screening commenced right after the publication of the TSCA Scope document, the criteria
for engineering and occupational exposure data were set to be broad to capture relevant information that
would support the initial scope. Thus, the inclusion and exclusion criteria for full text screening do not
reflect the refinements to the conceptual model and analysis plan resulting from problem formulation. As
part of the iterative process, EPA is in the process of refining the results of the lull text screening to
incorporate the changes in information/data needs to support the revised scope.
Table Apx D-3. Inclusion Criteria for Data Sources Reporting Engineering and Occupational
Exposure Data for Asbestos
KIM) l.lo mo ill
Bilk-nee

• Humans:
Workers, including occupational non-users
Receptors
• Environment:
Aquatic ecological receptors (release estimates input to Exposure)
Please refer to the conceptual models for more information about the ecological and human
receptors included in the TSCA risk evaluation.
Exposure
• Worker exposure to and relevant environmental releases of asbestos
o Inhalation as indicated in the conceptual model
o Water and air indicated in the conceptual model
Please refer to the conceptual models for more information about the routes and media/pathways
included in the TSCA risk evaluation.
Setting or
Scenario
• Any occupational setting or scenario resulting in worker exposure and relevant environmental
releases (includes all manufacturing, processing,use,disposalindicated in Table B-2 below
except (state none excluded or list excluded uses)
Outcomes
•	Quantitative estimates* of worker exposures and of relevant environmental releases from
occupational settings
•	General information and data related andrelevant to the occupationalestimates*
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* Metrics (e.g., mg/kg/day or mg/m3 for worker exposures, kg/site/day for releases) are determined by
toxicologists for worker exposures and by exposure assessors for releases; also, the Engineering Data
Needs (TableApx D-4) provides a list of related and relevant general information.
TSCA=Toxic Substances Control Act
Table Apx D-4. Engineering, Environmental Release and Occupational Data Necessary to Develop
the Environmental Release and Occupational Exposure Assessments	
Ohjcrliu'
Ih-U-rmi nod
tinriii» Scoping
"l\|K- <>f Dillil
General
Engineering
Asses sment (may
apply for either
or both
Occupational
Exposures and /
or Environmental
Releases)
1.	Description of the life cycle of the chemical(s) of interest, from manufacture to end-of-life (e.g., each
manufacturing, processing, or use step), and material flow between the industrial and commercial life cycle
stages. [Tags: Life cycle description, Life cycle diagram]3
2.	The total annual U.S. volume (lb/yr or kg/yr) of the chemical(s) of interest manufactured, imported,
processed, and used; and the share of total annual manufacturing and import volume that is processed or
used in each life cycle step. [Tags: Production volume, Import volume, Use volume, Percent PV] 3
3.	Description of processes, equipment, unit operations, and material flows and frequencies (lb/site-day or
kg/site-day anddays/yr; lb/site-batch andbatches/yr)of the chemical(s) of interest during each industrial/
commercial life cycle step. Note: if available, include weight fractions of the chemicals (s) of interest and
material flows of all associated primary chemicals (especially water). [Tags: Process description, Process
material flow rate, Annual operating days, Annual batches, Weight fractions (for each of above,
manufacture, import, processing,use)]3
4.	Basic chemical properties relevant for assessing exposures and releases, e.g., molecular weight, normal
boiling point, melting point, physical forms, and room temperature vapor pressure. [Tags: Molecular
weight, Boiling point, Melting point, Physical form, Vapor pressure, Water solubility]3
5.	Number of sites that manufacture, process,orusethe chemical(s) of interest for each industrial/
commercial life cycle step and site locations. [Tags: Numbers of sites (manufacture, import, processing,
use), Site locations]3
Occupational
Exposures
6.	Description of worker activities with exposure potential during the manufacture, processing, or use of the
chemical(s) of interest in each industrial/commercial life cycle stage. [Tags: Worker activities
(manufacture, import, processing,use)]3
7.	Potential routes of exposure (e.g., inhalation, dermal). [Tags: Routes of exposure (manufacture, import,
processing,use)]3
8.	Physical form of the chemical(s) of interestfor each exposure route (e.g., liquid, vapor, mist) and activity.
[Tags: Physical form during worker activities (manufacture, import, processing,use)]3
9.	Breathing zone (personal sample) measurements of occupational exposures to the chemical(s) of interest,
measured as time-weighted averages (TWAs), short-term exposures, or peak exposures in each
occupationallife cycle stage (or in a workplace scenario similar to an occupational life cycle stage). [Tags:
PBZ measurements (manufacture, import, processing, use)]3
10.	Area or stationary measurements of airborne concentrations ofthe chemical(s) of interest in each
occupational setting and life cycle stage (or in a workplace scenario similar to the life cycle stage of
interest). [Tags: Area measurements (manufacture, import, processing,use)]3
11.	For solids, bulk and dust particle size characterization data. [Tags:PSD measurements (manufacture,
import, processing,use)]3
12.	Dermal exposure data. [Tags: Dermal measurements (manufacture, import, processing,use)]
13.	Data needs associated with mathematical modeling (will be determined on a case-by-casebasis). [Tags:
Worker exposure modeling data needs (manufacture, import, processing, use)]3
14.	Exposure duration (hr/day). [Tags: Worker exposure durations (manufacture, import, processing,use)]3
15.	Exposure frequency (days/yr). [Tags: Worker exposure frequencies (manufacture, import, processing,
use)]3
16.	Number of workers who potentially handle or have exposure to the chemical(s) of interest in each
occupationallife cycle stage. [Tags: Numbers of workers exposed (manufacture, import, processing, use)]
a
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Ohjccliu'
Dclcrmineri
(lurinii Scoping
T\|)e iil° Diilii

17.	Personal protective equipment (PPE) types employed by the industries within scope. [Tags: Worker PPE
(manufacture, import, processing, use)]3
18.	Engineering controls employed to reduce occupational exposures in each occupational life cycle stage (or
in a workplace scenario similar to the life cycle stage of interest), and associated data or estimates of
exposure reductions. [Tags: Engineering controls (manufacture, import, processing,use), Engineering
control effectiveness data]3
Environmental
Releases
19.	Description of sources of potential environmental releases, including cleaning of residues from process
equipment and transport containers, involved during the manufacture, processing, or use of the
chemical(s) of interest in each life cycle stage. [Tags: Release sources (manufacture, import, processing,
use)]3
20.	Estimated mass (lb or kg) of the chemical(s) of interest released from industrial and commercial sites to
each environmental medium (air, water, land) and treatment anddisposalmethods (POTW, incineration,
landfill), including releases per site and aggregated over all sites (annual release rates, daily release rates)
[Tags: Release rates (manufacture, import, processing,use)]3
21.	Release or emission factors. [Tags: Emission factors (manufacture, import, processing,use)]3
22.	Number of release days peryear. [Tags: Release frequencies (manufacture, import, processing, use)]3
23.	Data needs associated with mathematical modeling (will be determined on a case-by-casebasis). [Tags:
Release modeling dataneeds (manufacture, import, processing,use)]3
24.	Waste treatment methods and pollution control devices employed by the industries within scope and
associated data on release/emission reductions. [Tags: Treatment/ emission controls (manufacture, import,
processing,use), Treatment/ emission controls removal/ effectiveness data]3
Notes:
a These are the tags included in the foil text screening form. The screener makes a selection from these
specific tags, which describe more specific types of data or information.
Abbreviations:
hr=Hour
kg=Kilogram(s)
lb=Pound(s)
yr=Year
PV=Particle volume
PBZ= Personal Breathing Zone
POTW=Publicly owned treatment works
PPE=Personal projection equipment
PSD=Particle size distribution
TWA=Time -weighted average
D-3 Inclusion Criteria for Data Sources Reporting Exposure Data on
General Population, Consumers and Ecological Receptors
EPA/OPPT developed PECO statements to guide the full text screening of exposure data/information for
human (i.e., general population, consumers, potentially exposure or susceptible subpopulations) and
ecological receptors. Subsequent versions of the PECO statements may be produced throughout the process
of screening and evaluating data for the chemicals undergoing TSCA risk evaluation. Studies that comply
with the inclusion criteria in the PECO statement are eligible for inclusion, considered for evaluation, and
possibly included in the exposure assessment. On the other hand, data sources are excluded if they do not
meet the criteria in the PECO statement. The asbestos-specific PECO is provided in Table Apx D-5.
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Since M text screening commenced right after the publication of the TSCA Scope document, the criteria
for exposure data were set to be broad to capture relevant information that would support the initial scope.
Thus, the inclusion and exclusion criteria for full text screening do not reflect the refinements to the
conceptual model and analysis plan resulting from problem formulation. As part of the iterative process,
EPA is in the process of refining the results of the lull text screening to incorporate the changes in
information/data needs to support the revised scope.
Asbestos Specific PECO Statement
Population: Asbestos has been detected in indoor and outdoor air as well as in many different freshwater
fishes and mussels from bodies of contaminated water. Potentially exposed populations include consumers
and bystanders in the home using imported asbestos aftermarket brake pads and friction products (e.g., from
do-it-yourself (DIY) replacement of asbestos aftermarket brake pads), and aquatic organisms which may
become exposed from asbestos from surface water.
Exposure: Expected primary and lesser exposure sources, pathways, and routes are noted in the table
below.
• The sources of asbestos are based on current marketed uses of asbestos only. The use profile of
asbestos has changed. Currently asbestos can be found in only certain articles that are readily
available for public purchase at common retailers. Asbestos is no longer mined in the U.S. and
production of asbestos diaphragms are the only known importer of raw asbestos. Currently marketed
articles include asbestos diaphragms, asbestos sheet gaskets, other gaskets (equipment seals),
vehicle friction products (non-passenger vehicles), brake blocks for oil drilling, imported asbestos
cement products and automotive brakes/linings. Legacy uses and associated/legacy disposals will be
excluded from the scope of the risk evaluation. These include asbestos-containing materials
remaining in older buildings or parts of older products for which manufacture, processing and
distribution in commerce are not currently intended, known or reasonably foreseen.
The pathways of asbestos are based on detection of possible presence in certain environmental and
biological media. Human-health-specific pathways include direct inhalation with articles containing
asbestos only.
The route of asbestos exposure for humans is inhalation exposure for only currently marketed asbestos
articles. Although many of the ongoing uses of asbestos articles are classified as non-friable, it can be made
friable due to physical and chemical wear and normal use of asbestos-containing products. While exposures
to asbestos can potentially occur via all routes, EPA anticipates that the most likely exposure route is
inhalation for adults.
Comparator (Scenario): Is there range/variation across exposure scenarios to help inform a comparison of
exposure to individuals or population groups (human or ecological)?
Outcome: Many authorities have established a causal association between asbestos exposure and lung
cancer and mesotheliomas and will be used as endpoint for exposure analysis. EPA expects to consider the
hazards of asbestos to aquatic organisms (including fish, aquatic invertebrates and aquatic plants) that are
potentially exposed under acute and chronic exposure conditions.
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TableApx D-5. Inclusion Criteria for Data Sources Reporting Asbestos Exposure Data on General
Population, Consumers and Ecological Receptors	
PECO Element
Evidence
Population
Human: Consumers; bystanders experiencing indoor exposures in the home to
current regulated uses of asbestos articles (e.g., changing aftermarket asbestos
brake pads). Adults are likely to be the only population to work with these
articles.

Ecological: Aquatic organisms (fish, aquatic invertebrates, plants);.
Exposure
Expected Exposure Sources, Pathways, Routes
Source: Secondary ambient air exposure to industrial activities if applicable
(chlor-alkali, sheet gasket manufacturing or commercial use, asbestos, brake
blocks for oil well drilling), consumer uses of articles containing asbestos
(aftermarket asbestos brakes/linings pads/shoes) that were not categorized as
legacy. [Asbestos has not been produced in the US since 2002, but can still be
imported. Legacy uses and legacy disposals are excluded from the problem
formulation.]
Pathway: waste streams described in the problem formulation (e.g., surface
water); indoor air from contact with asbestos articles (brakes);
Routes: inhalation (indoor)

Human: Consider only replacement of asbestos aftermarket articles [asbestos
brakes/linings and friction products (clutch facings and/or gaskets)] used for
consumer use in their garage at home. Inhalation monitoring data for commercial
auto worker (i.e., replacing brake pads) may be an applicable conservative
surrogate data source for this exposure assuming consumer exposure factors are
utilized.
Comparator
(Scenario)
The use of other asbestos articles may be more appropriate for occupational
settings (use and processing of asbestos woven material, replacing sheet gaskets,
workers replacing chloro- alkali diaphragms, replacement of brake blocks for oil
well drilling, automotive workers engaged in replacement of auto gaskets, brake
blocks for trucks, brake pads and shoes, clutch facings, and other asbestos friction
products), which would likely be out of scope for ambient exposures to general
population and consumers. However, reference material will also be collected and
scenarios identified if considered applicable and reasonable.

Ecological: Consider narrow use/source specific exposure scenarios for
imported asbestos cement products, gasket manufacture, or chloro-alklali plants
that release asbestos to surface water.
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„ „ Human: Chronic air, and water concentration estimates (fibers/cm3 or fibers/L)
Outcomes tor 	
Exposure 	
Concentration or Ecological: A narrow range of ecological receptors will be considered (range
Dose depending on available ecotoxicity data) using surface water concentrations from
releases to specific current asbestos releases to surface water (see sources above
	and in the problem formulation).	
D-4 Inclusion Criteria for Data Sources Reporting Human Health Hazards
EPA/OPPT developed an asbestos-specific PECO statement TableApx D-6 to guide the full text screening
of the human health hazard literature. Subsequent versions of the PECOs may be produced throughout the
process of screening and evaluating data for the chemicals undergoing TSCA risk evaluation. Studies that
comply with the criteria specified in the PECO statement will be eligible for inclusion, considered for
evaluation, and possibly included in the human health hazard assessment, while those that do not meet these
criteria will be excluded according to the exclusion criteria.
In general, the PECO statements were based on (1) information accompanying the TSCA Scope document,
and (2) preliminary review of the health effects literature from authoritative sources cited in the TSCA
Scope documents. When applicable, these authoritative sources (e.g., IRIS assessments, EPA/OPPT's Work
Plan Problem Formulations or risk assessments) will serve as starting points to identify PECO-relevant
studies.
Table Apx D-6. Inclusion Criteria for Data Sources Reporting Human Health Hazards Related to
Asbestos Exposure
i»i:c o
Ikininl
Pa|iers/l-ealures Included
Pa|iers/l-ealures r.M'luded
Human Evidence Streams b
Population
•	Any population
•	The following study designs will be considered:
o Controlled exposure, cohort, case-control, cross-
sectional, case-crossover
•	Non-human populations
•	Study designs other than controlled exposure, cohort,
case-control, cross-sectional, case-crossover
Exposure
•	Exposure to TSCA-defined asbestos fiber types:
o Chry sotile, Amosite, Anthophylite, Crocidolite,
Tremolite, and Anthophylite (includes studies of
mixed asbestos fiber types)c
•	Exposure based on measured or estimated concentrations
of asbestos and may be combined with estimates of
duration of exposure, such as exposure biomonitoring data
(e.g., lung tissue specimens), environmental or
occupational-setting monitoring data (e.g., ambient air
levels), job title or residence.
•	Exposure identified as or presumed to be from inhalation
routes
•	Route of exposure not by inhalation, type (i.e., oral,
dermal, intraperitoneal, or injection routes)
•	Non-quantitative measures of exposure
•	Less than 2 exposure groups present
•	Not pertaining to one or more of the TSCA-defined
asbestos fiber ty pesc
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PECO
Element
Papers/Features Included
Papers/Features Excluded

•	Quantitative measures or estimates of exposure only
•	For categorical exposures, a minimum of 2 exposure
groups (referent group + 1)

Comparator
•	An internal or external comparison population included,
(i.e., non-exposed or exposed to lower levels).
•	Exposure-response modeling results are presented in
sufficient detail (e.g., relative risk models for lung cancer
[i.e., SMR,RR, OR], additive models for mesothelioma,
potency factors [KL, KM], or regression coefficients
presented with variation)
•	No comparison group
•	No expo sure-response modeling results
Outcome
• Health Endpoints d'e:
o Lung cancer
o Mesothelioma
• Not pertaining to lung cancer or mesothelioma
health effects.
General
Considerations
I'apers/I-Valuivs Included
PapiTs/l-Vallllvs r.ullldi-d

•	Written in English f
•	Reports primary dataa
•	Full-text available
•	Reports both asbestos exposure and a health outcome
•	Publication date after 1986 d
•	Not written in English f
•	Reports secondary data (e.g., review papers)a
•	No full-text available (e.g., only a study
description/abstract, out-of-print text)
•	Reports an asbestos-related exposure or a health
outcome, but not both (e.g. incidence, prevalence
report)
•	Not published after 1986 d
3 Some of the studies that are excluded based on the PECO statement may be considered later during the systematic
review process. For asbestos, EPA will evaluate studies related to susceptibility and may evaluate, toxicokinetics and
physiologically based pharmacokinetic models after other data (e.g., human dose-response data) are reviewed. EPA
may also review other data as needed (e.g., mechanistic data including genotoxicity, review papers).
b Animal and mechanistic data are excluded during the full text screening phase of the systematic review process but
may be considered later (see footnote a).
c Papers reporting exposure to "asbestos" generally, not specific fiber tvpe of asbestos, will be included for further
consideration.
d EP A will review key and supporting studies in the IRIS assessment thii w ei e considered in the dose -response
assessment for non-cancer and cancer endpoints as well as studies published after the IRIS assessment.
0	EPA may screen lorha/ards other than those listed in the scope document if they were identified in the updated
literature search that accompanied the scope document.
1	EPA may translate studies as needed.
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