SEPA
EPA Document# EPA-740-R1-7002
June 2017
United States	Office of Chemical Safety and
Environmental Protection Agency	Pollution Prevention
Scope of the Risk Evaluation for
Cyclic Aliphatic Bromides Cluster
CASRN
NAME
25637-99-4
Hexabromocyclododecane
3194-55-6
1,2,5,6,9,10-Hexabromocyclododecane
3194-57-8
1,2,5,6-Tetrabromocyclooctane
June 2017

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TABLE OF CONTENTS
ACKNOWLEDGEMENTS	
ABBREVIATIONS	
EXECUTIVE SUMMARY	
1	INTRODUCTION	]
1.1	Regulatory History	1
1.2	Assessment History	1
1.3	Data and Information Collection	1
2	SCOPE OF THE EVALUATION	]
2.1	Physical and Chemical Properties	1
2.2	Conditions of Use	1
2.2.1	Data and Information Sources	1
2.2.2	Identification of Conditions of Use	1
2.3	Exposures	2
2.3.1	Fate and Transport	2
2.3.2	Releases to the Environment	2
2.3.3	Presence in the Environment and Biota	2
2.3.4	Environmental Exposures	3
2.3.5	Human Exposures	3
2.3.5.1	Occupational Exposures	3
2.3.5.2	Consumer Exposures	3
2.3.5.3	General Population Exposures	3
2.3.5.4	Potentially Exposed or Susceptible Subpopulations	3
2.4	Hazards (Effects)	5
2.4.1	Environmental Hazards	3
2.4.2	Human Health Hazards	3
2.4.2.1	Non-Cancer Hazards	3
2.4.2.2	Genotoxicity and Cancer Hazards	3
2.4.2.3	Potentially Exposed or Susceptible Subpopulations	3
2.5	Initial Conceptual Models	5
2.5.1	Initial Conceptual Model for Industrial and Commercial Activities and Uses: Potential
Exposures and Hazards	3
2.5.2	Initial Conceptual Model for Consumer Activities and Uses: Potential Exposures and
Hazards	3
2.5.3	Initial Conceptual Model for Environmental Releases and Wastes: Potential Exposures and
Hazards	A
2.6	Initial Analysis Plan	A
2.6.1 Exposure	A
2.6.1.1	Environmental Releases	A
2.6.1.2	Environmental Fate	A
2.6.1.3	Environmental Exposures	A
2.6.1.4	Occupational Exposures	A
2.6.1.5	Consumer Exposures	A
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2.6.1.6 General Population	46
2.6.2	Hazards (Effects)	46
2.6.2.1	Environmental Hazards	46
2.6.2.2	Human Health Hazards	47
2.6.3	Risk Characterization	47
REFERENCES	48
APPENDICES	52
Appendix A REGULATORY HISTORY	52
A.l Federal Laws and Regulations	52
A.2 State Laws and Regulations	53
A.3	International Laws and Regulations	54
Appendix B PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE INFORMATION	55
B.l	Process Information					55
B.l.l Manufacture (Including Import)	55
B.l.1.1 Domestic Manufacture	55
B.l.1.2 Import	55
B.l.2 Processing and Distribution	55
B.l.2.1 Processing as a Reactant/lntermediate	55
B.l.2.2 Incorporated into a Formulation, Mixture or Reaction Product	55
B.l.2.3 Incorporated into an Article	56
B.l.2.4 Recycling	57
B.l.3 Uses	57
B.l.3.1 Building/Construction Materials	57
B.l.3.2 Electrical and Electronic Products	58
B.l.3.3 Floor Coverings	58
B.l.3.4 Furniture and Furnishings	58
B.l.3.5 Fabric, Textile and Leather Products	58
B.l.3.6 Other Products	58
B.1.4 Disposal	58
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LIST OF TABLES
Table 1-1. Assessment History of HBCD	14
Table 2-1. Physical and Chemical Properties of HBCD	17
Table 2-2. Production Volume of HBCD in CDR Reporting Period (2012 to 2015) 	19
Table 2-3. Categories and Subcategories of Conditions of Use for HBCD	23
Table 2-4. Environmental Fate Characteristics of HBCD	28
LIST OF FIGURES
Figure 2-1. Initial HBCD Life Cycle Diagram	20
Figure 2-2. Initial HBCD Conceptual Model for Industrial and Commercial Activities and Uses: Potential
Exposures and Hazards	38
Figure 2-3. Initial HBCD Conceptual Model for Consumer Activities and Uses: Potential Exposures and
Hazards	40
Figure 2-4a. Initial HBCD Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards	42
Figure 2-4b. Initial HBCD Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards	43
LIST OF APPENDIX TABLES
Table_Apx A-l. Federal Laws and Regulations	52
Table_Apx A-2. State Laws and Regulations	53
Table_Apx A-3. Regulatory Actions by other Governments and Tribes	54
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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).
Acknowledgements
The OPPT Assessment Team gratefully acknowledges participation or input from EPA's Office of
General Counsel, Office of Research and Development, Office of Children's Health Protection and
assistance from EPA contractors CSRA LLC (Contract No. CIO-SP3, HHSN316201200013W), ERG
(Contract No. EP-W-12-006), ICF (Contract No. EP-C-14-001) and SRC (Contract No. EP-W-12-003).
Docket
Supporting information can be found in public docket: EPA-HQ-QPPT-2016-0735.
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
°C	Degrees Celsius
atm	Atmosphere(s)
BAF	Bioaccumulation Factor
BCF	Bioconcentration Factor
BFRIP	Brominated Flame Retardant Industry Panel
C&D	Construction and Demolition
CAA	Clean Air Act
CASRN	Chemical Abstracts Service Registry Number
CBI	Confidential Business Information
CCL	Candidate Contaminant List
CDR	Chemical Data Reporting
CDT	Cyclododecatriene
CEC	Commission for Environmental Cooperation
cm3	Cubic Centimeter(s)
COC	Concentration of Concern
CPCat	Chemical and Product Categories
CPSC	Consumer Product Safety Commission
CSCL	Chemical Substances Control Law
EC	European Commission
ECHA	European Chemicals Agency
EPA	Environmental Protection Agency
EPCRA	Emergency Planning and Community Right-to-Know Act
EPS	Expanded Polystyrene
ESD	Emission Scenario Document
FHSA	Federal Hazardous Substances Act
g	Gram(s)
HAP	Hazardous Air Pollutant
HBCD	Hexabromocyclododecane
HIPS	High Impact Polystyrene
HPV	High Production Volume
IRIS	Integrated Risk Information System
kg	Kilogram(s)
Koa	Octanol:Air Partition Coefficient
L	Liter(s)
lb	Pound
LCD	Liquid-Crystal Display
Log Koc	Logarithmic Organic Carbon:Water Partition Coefficient
Log Kow	Logarithmic OctanokWater Partition Coefficient
m3	Cubic Meter(s)
lag	Microgram(s)
mmHg	Millimeter(s) of Mercury
MSDS	Material Safety Data Sheet
MSWLF	Municipal Solid Waste Landfill
NEI	National Emissions Inventory
NICNAS	National Industrial Chemicals Notification and Assessment Scheme
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NIH
National Institute of Health
NIOSH
National Institute of Occupational Safety and Health
NTP
National Toxicology Program
OCSPP
Office of Chemical Safety and Pollution Prevention
OECD
Organisation for Economic Co-operation and Development
OPPT
Office of Pollution Prevention and Toxics
OSHA
Occupational Safety and Health Administration
PBPK
Physiologically Based Pharmacokinetic
PEC
Predicted Environmental Concentration
PFIA
Problem Formulation and Initial Assessment
POD
Point of Departure
POP
Persistent Organic Pollutant
POTW
Publicly Owned Treatment Works
PPm
Part(s) per Million
PVC
Polyvinylchloride
QC
Quality Control
REACH
Registration, Evaluation, Authorisation and Restriction of Chemicals
RoHS
Restriction of Hazardous Substances
SDS
Safety Data Sheet
SHGB
Sex Hormone Binding Globulin
SIDS
Screening Information Data Set
SIPS
Structural Insulated Panels
SNUR
Significant New Use Rule
SVHC
Substance of Very High Concern
TCCR
Transparent, Clear, Consistent, and Reasonable
TRI
Toxics Release Inventory
TSCA
Toxic Substances Control Act
U.S.
United States
UNEP
United Nations Environment Programme
WEEE
Waste Electrical and Electronic Equipment
WWTP
Wastewater Treatment Plant
XPS
Extruded Polystyrene
XPSA
Extruded Polystyrene Association
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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). HBCD 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. This document fulfills the TSCA § 6(b)(4)(D) requirement for
HBCD.
This document presents the scope of the risk evaluation to be conducted for HBCD. If a hazard,
exposure, condition of use or potentially exposed or susceptible subpopulation has not been discussed,
EPA, at this point in time, is not intending to include it in the scope of the risk evaluation. As per the
rulemaking, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act
(TSCA), with respect to conditions of use in conducting a risk evaluation under TSCA, EPA will first
identify "circumstances" that constitute "conditions of use" for each chemical. While EPA interprets
this as largely a factual determination—i.e., EPA is to determine whether a chemical substance is
actually involved in one or more of the activities listed in the definition—the determination will
inevitably involve the exercise of some discretion.
To the extent practicable, EPA has aligned this scope document with the approach set forth in the risk
evaluation process rule; however, the scope documents for the first 10 chemicals in the risk evaluation
process differ from the scope documents that EPA anticipates publishing in the future. Time
constraints have resulted in scope documents for the first 10 chemicals that are not as refined or
specific as future scope documents are anticipated to be.
Because there was insufficient time for EPA to provide an opportunity for comment on a draft of this
scope document, as it intends to do for future scope documents, EPA will publish and take public
comment on a problem formulation document which will refine the current scope, as an additional
interim step, prior to publication of the draft risk evaluation for HBCD. This problem formulation is
expected to be released within approximately 6 months of publication of the scope.
The cyclic aliphatic bromide cluster chemicals, including HBCD (Chemical Abstracts Service Registry
Number [CASRN] 25637-99-4), 1,2,5,6,9,10-hexabromocyclododecane (1,2,5,6,9,10-HBCD; CASRN
3194-55-6) and 1,2,5,6-tetrabromocyclooctane (CASRN 3195-57-8) are flame retardants. Uses for
1,2,5,6-tetrabromocyclooctane have not been identified. For the purposes of this scope document, the
use of "HBCD" refers to either CASRN 25637-99-4 or 3194-55-6, or both.
The primary use of HBCD is as a flame retardant in expanded polystyrene (EPS) foam and extruded
polystyrene (XPS) foam in the building and construction industry for thermal insulation boards and
laminates for sheathing products; however, it may also be used to a limited extent in plastics (additive)
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and textiles (backcoating). Information gathered from research, industry and consumer product
organizations, however, has led EPA to believe that HBCD is no longer used in consumer textile
applications outside of the automotive industry.
A Problem Formulation and Initial Risk Assessment (PFIA) for the Cyclic Aliphatic Bromides Cluster was
published for public comment in 2015; however, a draft risk assessment was not completed prior to
the passing of amended TSCA. As in the 2015 PFIA document, EPA expects to review current published
risk assessments and scenarios for workers, consumers, the general population and biota. EPA now
also expects to consider the conditions of use as described in this scope document. Subsequent to the
PFIA, HBCD has been listed on the Toxics Release Inventory (TRI); the first reporting year is 2017. EPA
also promulgated a significant new use rule (SNUR) for use in consumer textiles 80FR 57293.
The initial conceptual models presented in Section 2 identify conditions of use; exposure pathways
(e.g., media); exposure routes (e.g., inhalation, dermal, oral); potentially exposed populations,
including potentially exposed or susceptible subpopulations; and hazards EPA expects to evaluate
based on the inherent hazards of the chemical.
This document presents the scenarios in which workers and occupational non-users may be exposed to
HBCD during a variety of conditions of use. The manufacturing, processing, distribution and industrial
and commercial use of HBCD could result in exposures to workers and occupational non-users via
inhalation of particulates, dermal contact with particulates, ingestion of particulates that deposit in the
upper respiratory tract and are swallowed or ingestion of HBCD following hand to mouth contact.
Consumers and bystanders may also be exposed to HBCD via inhalation of particulates, dermal contact
with HBCD in articles and oral exposure via ingestion of settled dust or mouthing of articles. For HBCD,
EPA believes that workers, consumers, and bystanders as well as certain other groups of individuals
may experience greater exposures than the general population. EPA will evaluate whether other
groups of individuals within the general population may be exposed via pathways that are distinct from
the general population due to unique characteristics (e.g., life stage, behaviors, activities, duration) or
have greater susceptibility than the general population, and should therefore be considered relevant
potentially exposed or susceptible subpopulations for purposes of this risk evaluation.
Exposures to the general population may occur from industrial releases. The manufacturing,
processing, distribution and use of HBCD can result in releases to air, water, sediment and soil. EPA
expects to consider exposures to the general population and environment via inhalation of air emitted
from manufacturing, processing and use facilities and from water, sediments and soils that may receive
releases or wastes from such facilities. As data suggest that HBCD is persistent and bioaccumulative,
routes of exposure may include ingestion of water, breast milk, and edible aquatic and terrestrial biota.
HBCD has been the subject of numerous health hazard and risk assessments. Any existing assessments
will be a starting point as EPA will conduct a systematic review of the literature, including new
literature since the existing assessments, as available in HBCD (CASRN 25637-99-4, 3194-55-6, 3194-57-
8) Bibliography: Supplemental File for the TSCA Scope Document, EPA-HQ-QPPT-2016-0735). Human
health hazards of HBCD have been reviewed previously and include liver toxicity, thyroid toxicity,
reproductive/developmental toxicity, neurotoxicity, immunotoxicity and sensitization/irritation, all of
which EPA/OPPT expects to consider in the scope of the TSCA risk evaluation. HBCD hazards to fish,
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aquatic plants, sediment invertebrates and terrestrial organisms have also previously been assessed.
These hazards will be evaluated based on the specific exposure scenarios identified.
The initial analysis plan describes EPA's plan for conducting systematic review of readily available
information and identification of assessment approaches to be used in conducting the risk evaluation
for HBCD. The initial analysis plan will be used to develop the problem formulation and final analysis
plan for the risk evaluation of HBCD.
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1 INTRODUCTION
This document presents the scope of the risk evaluation to be conducted for HBCD. If a condition of
use has not been discussed, EPA, at this point in time, is not intending to include that condition of use
in the scope of the risk evaluation. Moreover, during problem formulation EPA may determine that not
all conditions of use mentioned in this scope will be included in the risk evaluation. Any condition of
use that will not be evaluated in-depth will be clearly described in the problem formulation document.
On June 22, 2016, the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amended
the Toxic Substances Control Act (TSCA), the nation's primary chemicals management law, was signed
into law. The new law includes statutory requirements and deadlines for actions related to conducting
risk evaluations of existing chemicals.
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). 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. On February 14, 2017, EPA convened a public meeting to
receive input and information to assist the Agency in its efforts to establish the scope of the risk
evaluations under development for the ten chemical substances designated in December 2016 for risk
evaluations pursuant to TSCA. EPA provided the public an opportunity to identify information, via oral
comment or by submission to a public docket, specifically related to the conditions of use for the ten
chemical substances. EPA used this information in developing this scope document, which fulfills the
TSCA § 6(b)(4)(D) requirement for HBCD.
As per the rulemaking, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances
Control Act (TSCA), in conducting a risk evaluation under TSCA EPA will first identify "circumstances"
that constitute "conditions of use" for each chemical. While EPA interprets this as largely a factual
determination —i.e., EPA is to determine whether a chemical substance is actually involved in one or
more of the activities listed in the definition—the determination will inevitably involve the exercise of
some discretion. Based on legislative history, statutory structure and other evidence of Congressional
intent, EPA has determined that certain activities may not generally be considered to be conditions of
use. In exercising its discretion, for example, EPA would not generally consider that a single
unsubstantiated or anecdotal statement (or even a few isolated statements) on the internet that a
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chemical can be used for a particular purpose would necessitate concluding that this represented part
of the chemical substance's "conditions of use." As a further example, although the definition could be
read literally to include all intentional misuses (e.g., inhalant abuse), as a "known" or "reasonably
foreseen" activity in some circumstances, EPA does not generally intend to include such activities in
either a chemical substance's prioritization or risk evaluation. In addition, EPA interprets the mandates
under section 6(a)-(b) to conduct risk evaluations and any corresponding risk management to focus on
uses for which manufacture, processing, or distribution in commerce is intended, known to be
occurring, or reasonably foreseen (i.e., prospective or on-going), 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. For instance, the conditions of use for purposes of
section 6 might reasonably include the use of a chemical substance in insulation where the
manufacture, processing, or distribution in commerce for that use is prospective or on-going, but
would not include the use of the chemical substance in previously installed insulation, if the
manufacture, processing or distribution for that use is not prospective or on-going. 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. That said, in a particular risk evaluation, EPA may consider background
exposures from legacy use, associated disposal, and legacy disposal as part of an assessment of
aggregate exposure or as a tool to evaluate the risk of exposures resulting from non-legacy uses.
Furthermore, in exercising its discretion under section 6(b)(4)(D) to identify the conditions of use that
EPA expects to consider in a risk evaluation, EPA believes it is important for the Agency to have the
discretion to make reasonable, technically sound scoping decisions in light of the overall objective of
determining whether chemical substances in commerce present an unreasonable risk. Consequently,
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 meriting an unreasonable risk consideration. For example, EPA intends to exercise discretion
in addressing circumstances where the chemical substance subject to scoping is unintentionally
present as an impurity in another chemical substance that is not the subject of the pertinent scoping,
in order to determine which risk evaluation the potential risks from the chemical substance should be
addressed in. As an additional example, EPA may, on a case-by-case basis, exclude uses that EPA has
sufficient basis to conclude would present only "de minimis" exposures. This could include uses that
occur in a closed system that effectively precludes exposure, or use as an intermediate. During the
scoping phase, EPA may also exclude a condition of use that has been adequately assessed by another
regulatory agency, particularly where the other agency has effectively managed the risks.
The situations identified above are examples of the kinds of discretion that EPA will exercise in
determining what activities constitute conditions of use, and what conditions of use are to be included
in the scope of any given risk evaluation. See the preamble to Procedures for Chemical Risk Evaluation
Under the Amended Toxic Substances Control Act (TSCA) for further discussion of these issues.
To the extent practicable, EPA has aligned this scope document with the approach set forth in the risk
evaluation process rule; however, the scope documents for the first 10 chemicals in the risk evaluation
process differ from the scope documents that EPA anticipates publishing in the future. The first 10
chemical substances were not subject to the prioritization process that will be used in the future in
accordance with amendments to TSCA. EPA expects to collect and screen much of the relevant
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information about chemical substances that will be subject to the risk evaluation process during and
before prioritization. The volume of data and information about the first 10 chemicals that is available
to EPA is extremely large and EPA is still in the process of reviewing it, since the Agency had limited
ability to process the information gathered before issuing the scope documents for the first 10
chemicals. As a result of the statutory timeframes, EPA had limited time to process all of the
information gathered during scoping for the first 10 chemicals within the time provided in the statute
for publication of the scopes after initiation of the risk evaluation process. For these reasons, EPA's
initial screenings and designations with regard to applicability of data (e.g., on-topic vs. off-topic
information and data) may change as EPA progresses through the risk evaluation process. Likewise, the
Conceptual Models and Analysis Plans provided in the first 10 chemical scopes are designated as
"Initial" to indicate that EPA expects to further refine them during problem formulation.
The aforementioned time constraints have resulted in scope documents for the first 10 chemicals that
are not as refined or specific as future scope documents are anticipated to be. In addition, there was
insufficient time for EPA to provide an opportunity for comment on a draft of this scope document, as
it intends to do for future scope documents. For these reasons, EPA will publish and take public
comment on a Problem Formulation document which will refine the current scope, as an additional
interim step, prior to publication of the draft risk evaluations for the first 10 chemicals. This problem
formulation is expected to be released within approximately 6 months of publication of the scope.
1.1	Regulatory History
EPA conducted a search of existing domestic and international laws, regulations and assessments
pertaining to HBCD. EPA compiled this summary from data available from federal, state, international
and other government sources, as cited in Appendix A. EPA may evaluate and consider the impact of
these existing laws and regulations in the problem formulation step to determine what, if any, further
analysis might be necessary as part of risk evaluation.
Federal Laws and Regulations
HBCD 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.
State Laws and Regulations
HBCD is subject to state statutes or regulations implemented by state agencies or departments. A
summary of state laws, regulations and implementing authorities is provided in Appendix A.2.
Laws and Regulations in Other Countries and International Treaties or Agreements
HBCD 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 has 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,
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hazards, exposures and potentially exposed or susceptible subpopulations—information useful to EPA
in preparing this scope for risk evaluation. Table 1-1 shows the assessments that have been conducted.
In addition to using this information, EPA intends to conduct a full review of the data collected (see
HBCD (CASRN 25637-99-4, 3194-55-6, 3194-57-8) Bibliography: Supplemental File for the TSCA Scope
Document, EPA-HQ-QPPT-2016-0735) using the literature search strategy (see Strategy for Conducting
Literature Searches for HBCD: Supplemental File for the TSCA Scope Document, EPA-HQ-QPPT-2016-
0735) to ensure that EPA is considering information that has been made available since these
evaluations were conducted.
A Problem Formulation and Initial Assessment (PFIA) for the Cyclic Aliphatic Bromides Cluster was
published in 2015 (U.S. EPA. 2015b); however, a draft risk assessment was not completed. EPA/OPPT
expects to review the public comments received on the 2015 PFIA during problem formulation.
EPA/OPPT outlined plans to evaluate existing assessments in the 2015 PFIA for HBCD (U.S. EPA. 2015b).
including those listed in Table 1-1 below. EPA/OPPT also outlined several exposure scenarios, including
occupational exposure to HBCD during HBCD and polystyrene foam manufacture and processing;
general population from releases to the environment; environmental exposure from releases to the
environment; and consumer exposure from the use of products or articles containing HBCD in indoor
environments.
Table 1-1. Assessment History of HBCD	
Authoring Organization
Assessment
EPA assessments
EPA, Office of Chemical Safety and Pollution Prevention
(OCSPP), Office of Pollution Prevention and Toxics
(OPPT)
Initial Risk Based Prioritization of High
Production Volume Chemicals.
Chemical/Category:
Hexabromocvclododecane (HBCD) (2008)
EPA, OCSPP, OPPT
Hexabromocvclododecane (HBCD) Action
Plan (2010)
EPA, OCSPP, OPPT
Flame Retardant Alternatives for
Hexabromocvclododecane (HBCD) (2014b)
EPA, OCSPP, OPPT
Toxic Chemical Work Plan Problem
Formulation and Initial Assessment for
HBCD, Cvclic Aliphatic Bromides
Cluster(2015b)
Other U.S.-based organizations
Consumer Product Safety Commission (CPSC)
CPSC Staff Exposure and Risk Assessment of
Flame Retardant Chemicals in Residential
Upholstered Furniture (CPSC, 2001)
International
Organisation for Economic Co-operation and
Development (OECD), Screening Information Data Set
(SIDS)
OECD SIDS Initial Assessment Profile (SIAP)
(2007)
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Authoring Organization
Assessment
European Commission (EC), European Chemicals
Bureau
European Union Risk Assessment Report,
Hexabromocvclododecane CASRN 25637-99-
4. EINECS No: 247-148-4 (2008)
United Nations Environment Programme (UNEP);
Stockholm Convention on Persistent Organic Pollutants
(POPs)
Hexabromocvclododecane Draft Risk Profile
(2010)
Environment Canada and Health Canada
Draft Screening Assessment of
Hexabromocvclododecane (2011)
Australian Government Department of Health, National
Industrial Chemicals Notification and Assessment
Scheme (NICNAS)
Prioritv Existing Chemical Assessment
Report, Hexabromocvclododecane (2012)
1.3 Data and Information Collection
EPA/OPPT generally applies a process and workflow that includes: (1) data collection; (2) data
evaluation; and (3) data integration of the scientific data used in risk assessments developed under
TSCA. Scientific analysis is often iterative in nature as new knowledge is obtained. Hence, EPA/OPPT
expects that multiple refinements regarding data collection will occur during the process of risk
evaluation.
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 exposures,
human exposures, including potentially exposed or susceptible subpopulations; ecological hazard 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. Generally, 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
HBCD: Supplemental File for the TSCA Scope Document (EPA-HQ-QPPT-2016-0735) 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 HBCD: Supplemental File for the TSCA Scope
Document (EPA-HQ-QPPT-2016-0735). 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
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data extraction and data evaluation steps. Prior to full-text review, EPA/OPPT anticipates refinements
to the search and 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; environmental exposures, human 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) but 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. Strategy for Conducting Literature Searches
for HBCD: Supplemental File for the TSCA Scope Document (EPA-HQ-QPPT-2016-0735) 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 HBCD (CASRN 25637-99-4, 3194-55-6, 3194-
57-8) Bibliography: Supplemental File for the TSCA Scope Document (EPA-HQ-QPPT-2016-0735) and will
be 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 HBCD (CASRN 25637-99-4,
3194-55-6, 3194-57-8) Bibliography: Supplemental File for the TSCA Scope Document (EPA-HQ-QPPT-
2016-0735). This document provides a comprehensive list (bibliography) of the sources of data
identified by the initial search and the initial categorization for on-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.
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2 SCOPE OF THE EVALUATION
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 is
including an initial life cycle diagram and initial conceptual models that describe the actual or potential
relationships between HBCD and human and ecological receptors. An initial 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 HBCD. As noted previously,
EPA intends to refine this analysis plan during the problem formulation phase of risk evaluation.
2.1 Physical and Chemical Properties
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 that EPA intends to consider. For scope development, EPA considered the measured or
estimated physical-chemical properties set forth in Table 2-1.
HBCD is a white odorless non-volatile solid that is used as a flame retardant. Technical HBCD is often
characterized as a mixture of mainly three diastereomers, which differ only in the spatial disposition of
the atoms. Commercial-grade HBCD may contain some impurities, such as tetrabromocyclododecene
or other isomeric HBCDs (UNEP. 2010). which are not separately included in this scope. The density of
HBCD is greater than that of water (2.24 g/cm3 at 20°C). It has low water solubility (66 |ag/L at 20°C)
and a log octanokwater partition coefficient (log Kow) of 5.62.
Table 2-1. Physical and Chemical Properties of HBCD	
Property
Valuea
References
Molecular formula
Ci2Hi8Br6

Molecular weight
641.7 g/mole

Physical form
White solid; odorless
EINECS (2008)
Melting point
Ranges from approximately:
172-184°C to 201-205°C
EINECS (2008)
Boiling point
>190°C (decomposes)
EINECS (2008)
Density
2.24 g/cm3
EINECS (2008)
Vapor pressure
4.7E-07 mmHg at 21°C
EINECS (2008)
Vapor density
Not readily available
EINECS (2008)
Water solubility
66 |ag/L at 20°C
EINECS (2008)
Octanokwater partition
coefficient (log Kow)
5.625 at 25°C
EINECS (2008)
Henry's Law constant
7.4E-06 atm-m3/mole (estimated)
U.S. EPA (2012a)
Flash point
Not readily available
EINECS (2008)
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Property
Valuea
References
Autoflammability
Decomposes at >190°C
EINECS (2008)
Viscosity
Not readily available
EINECS (2008)
Refractive index
Not readily available
EINECS (2008)
Dielectric constant
Not readily available
EINECS (2008)
a Measured unless otherwise noted.
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
As the first step in preparing these scope documents, EPA identified, based on reasonably available
information, the conditions of use for the subject chemicals. As further described in this document,
EPA searched a number of available data sources (e.g., Use and Market Profile for HBCD, EPA-HQ-
QPPT-2016-0735). Based on this search, EPA published a preliminary list of information and sources
related to chemical conditions of use (see Preliminary Information on Manufacturing, Processing,
Distribution, Use, and Disposal: HBCD, EPA-HQ-QPPT-2016-0735-0003) 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 conditions of use and verifying conditions of use identified by EPA. The information
and input received from the public and stakeholder meetings has been incorporated into this scope
document to the extent appropriate, as indicated in Table 2-3. Thus, EPA believes the manufacture,
processing, distribution, use and disposal activities identified in these documents constitute the
intended, known, and reasonably foreseen activities associated with the subject chemicals, based on
reasonably available information. The documents do not, in most cases, specify whether activity under
discussion is intended, known, or reasonably foreseen, in part due to the time constraints in preparing
these documents.
2.2.2	Identification of Conditions of Use
As part of the scope, an initial life cycle diagram is provided (Figure 2-1) depicting the conditions of use
that are within the scope of the risk evaluation during various life cycle stages including manufacturing,
processing, use (industrial, commercial, consumer; when distinguishable), distribution and disposal.
The information is grouped according to Chemical Data Reporting (CDR) processing codes and use
categories (including functional use codes for industrial uses and product categories for industrial,
commercial and consumer uses), in combination with other data sources (e.g., published literature and
consultation with stakeholders) to provide an overview of conditions of use. EPA notes that some
subcategories of use may be grouped under multiple CDR categories.
For the purposes of this scope, CDR definitions were used. CDR 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
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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 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. 2016b).
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 (U.S. EPA. 2016b). when the volume was
not claimed confidential business information (CBI). The 2016 CDR reporting data for HBCD are
provided in Table 2-2 for HBCD from EPA's CDR database (U.S. EPA. 2016b).
Table 2-2. Production Volume of HBCD in CDR Reporting Period (2012 to 2
015) a
Reporting Year
2012
2013
2014
2015
Total Aggregate
Production Volume (lbs)
CASRN 25637-99-4
1-10 million
1-10 million
1-10 million
1-10 million
CASRN 3194-55-6
10-50 million
10-50 million
1-10 million
1-10 million
aThe CDR data for the 2016 reporting period is available via ChemView (https://iava.eoa.gov/chemview) (U.S. EPA.
2016b). Because of an ongoing CBI substantiation process reauired bv amended TSCA. the CDR data available in the scope
document is more specific than currently in ChemView.
Data reported for the CDR period for 2016 for HBCD indicate that between 1 and 10 million lbs of each
CASRN was manufactured in or imported into the United States in 2015; the precise production volume
is CBI (U.S. EPA. 2017a). For both CASRNs, site-specific production volumes for the 2011 reporting year
were withheld as TSCA CBI.
2016 CDR data pertaining to facility and specific use are not yet publicly available (U.S. EPA. 2016b).
Five sites are identified in the 2012 CDR database (U.S. EPA. 2012b) as manufacturers or importers of
HBCD: Albemarle Corporation, BASF Corporation, The Dow Chemical Company and two sites where CBI
was claimed (U.S. EPA. 2012b). Albemarle manufactures HBCD flame retardants (Albemarle. 2000).
Both BASF and Dow Chemical indicate in the CDR data that they are importers; however, trade names
of the BASF or Dow Chemical products that use or contain HBCD could not be found in a literature
search. In 2011, two sites imported and three sites domestically manufactured at least one of the
chemicals.
Since the 2012 CDR data were collected, industry has indicated either partial or complete replacement
of HBCD in their product lines (U.S. EPA. 2017c). No data are available to quantify these changes.
Figure 2-1 depicts the initial life cycle diagram of HBCD from manufacture to the point of disposal. The
initial life cycle diagram does not distinguish between industrial, commercial and consumer uses; EPA
will further investigate and define the differences between these uses during risk evaluation. Based on
2012 CDR data (U.S. EPA. 2012b). EPA expects that HBCD is primarily used in the production of building
and construction materials.
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MFG/IMPORT
PROCESSING
INDUSTRIAL, COMMERCIAL, CONSUMER USES a
RELEASES and WASTE DISPOSAL
Manufacture
(Includes Import)
CASRN 25637-99-4
(1-10 million lbs)
CASRN 3194-55-6
(1-10 million lbs)
Processing as
Reactant/lntermediate
(Volume CBI)
Incorporated into
Formulation, Mixture, or
Reaction Product
(Volume CBI)
e.g., manufacture of EPS resin
beads, compounding of XPS
masterbatch, micronisation,
formulation of polymer-based
dispersions
Incorporated into Article
(Volume CBI)
e.g., manufacture of XPS and
EPS, manufacture of SIPs from
XPS and EPS, manufacture of
HIPS, textile and fabric
finishing, fabric coating,
carpet and rug mills,
manufacture of interior
fabrics in automobiles
Building/Construction Materials b
e.g., insulation material for residential, public
and commercial buildings or other structures
Electrical and Electronic Products
e.g., wire and cable, computers, distribution
boxes, audio-visual equipment,
refrigerator lining
Floor Coverings
e.g., carpets and rug
Furniture and Furnishings
e.g., institutional furniture
Other Products
e.g., product packaging, children's products,
bean bags
Fabric, Textile and Leather Products0
e.g., interior fabrics for automobiles,
other non-consumer textile products
Recycling
Emissions to Air
Wastewater d
Liquid Wastes d
Solid Wastes
See Figure 2-4a and 2-4b for
Environmental Releases and Wastes
I Manufacture (Includes Import)	1 I Processing	I 1 Uses. At the scope level of detail in the life cycle diagram EPA is
not distinguishing between industrial/commercial/consumer uses. The
differences between these uses will be further investigated and defined
during risk evaluation.
Figure 2-1. Initial HBCD Life Cycle Diagram
The initial 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, consumer), distribution and disposal. The production volumes shown are
for reporting year 2015 from the 2016 CDR reporting period (U.S. EPA, 2016b). Activities related to distribution (e.g., loading, unloading) will
be considered throughout the HBCD life cycle, rather than using a single distribution scenario. The diagram includes the major use of HBCD
(insulation material for buildings or other structures) as well as reasonably foreseen uses.
a See Table 2-3 for additional uses not mentioned specifically in this diagram. Note that insulation materials for buildings (or other structures) is confirmed as an
ongoing use.
b 2012 CDR data (U.S. EPA, 2012b) indicate that the major use of HBCD is in building and construction materials.
c Significant New Use Rule (SNUR) (U.S. EPA, 2015a): EPA requires 90-day notification before manufacture or processing of HBCD in consumer textiles, except those
used in motor vehicles.
d Wastewater: combination of water and organic liquid, where the organic content is <50%. Liquid wastes: combination of water and organic liquid, where the organic
content is >50%.
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Descriptions of the industrial, commercial and consumer use categories identified from the 2016 CDR
and included in the life cycle diagram are summarized below (U.S. EPA. 2016b). The descriptions
provide a brief overview of the use category; Appendix B contains more detailed descriptions (e.g.,
process descriptions, worker activities, process flow diagrams, equipment illustrations) for each
manufacture, processing, use and disposal category. The descriptions provided below are primarily
based on the corresponding industrial function category and/or commercial and consumer product
category descriptions from the 2016 CDR and can be found in EPA's Instructions for Reporting 2016
TSCA Chemical Data Reporting (U.S. EPA. 2016a).
Major Use
Expanded Polystyrene (EPS) and Extruded Polystyrene (XPS) Foam
"Building/Construction Materials" include products containing HBCD as a flame retardant primarily in
XPS and EPS foam insulation products that are used for the construction of residential, public,
commercial or other structures (UNEP. 2010; Weil and Levchik. 2009).
Use in EPS and XPS foam accounted for 95% of all HBCD applications in the past decade (U.S. EPA.
2013; UNEP. 2010). Based on information from market reports (U.S. EPA. 2017c). HBCD is used
primarily in construction materials. The building and construction industry uses EPS and XPS foam in
thermal insulation boards and laminates for sheathing products. EPS foam prevents freezing, provides
a stable fill material and creates high-strength composites in construction applications. XPS foam board
is used mainly for roofing applications and architectural molding. HBCD is used in both types of foams
because it is highly effective at levels less than 1% and, therefore, maintains the insulation properties
of EPS and XPS foam (Morose. 2006). EPS foam boards contain approximately 0.5% HBCD by weight in
the final product and XPS foam boards contain 0.5-1% HBCD by weight (Public comment, EPA-HQ-
QPPT-2016-0735-0017) (XPSA. 2017: U.S. EPA. 2014b: Morose. 2006).
International bans, the availability of alternatives and reported industry use statements have resulted
in the use of HBCD in EPS and XPS foam declining or no longer occurring in the United States. One
commenter, who represents all major North American manufacturers of EPS, reports that its members
have phased out HBCD in the production of EPS resins (Public comment, EPA-HQ-QPPT-2016-0735-
0026). An estimated 80-85% of EPS rigid foam insulation manufactured in the United States is supplied
by EPS Industry Alliance members (EPS Industry Alliance. 2017). The status of HBCD use by non-
member companies is not known. Furthermore, according to the American Chemistry Council, EPS
resin manufacturers no longer have supplies of HBCD, except for importation (Reiter. 2017).
Additionally, an industry association highlights that three main U.S. manufacturers of XPS have
announced their intention to discontinue manufacturing HBCD (U.S. EPA. 2017c). The status of the use
of HBCD in XPS foam is unknown (Public comment, EPA-HQ-QPPT-2016-0735-0017).
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Reasonably Foreseen Uses
Minor uses of HBCD identified both through CDR and secondary sources are described in this section.
EPA/OPPT expects to consider these uses during problem formulation.
Use in High Impact Polystyrene (HIPS)
A small amount of HBCD may also be used as a flame retardant in HIPS materials for the manufacture
of products in the "Electrical and Electronic Products" category. It is unclear as to the amount of HBCD
currently used in HIPS in the U.S.
As of 2009, in both the United States and Europe, HBCD was used as a flame retardant in HIPS for
electrical and electronic appliances, such as audio-visual equipment, refrigerator lining and some wire
and cable applications (ECHA. 2009; Morose. 2006). Use in television sets at that time was the
predominant application of HIPS (Weil and Levchik. 2009).
Use in Textiles
HBCD may have a minor application in textile coatings for the manufacture of products in the "Fabric,
Textile and Leather Products," "Floor Coverings," and "Furniture and Furnishings" category, including
interior fabrics for automobiles.
In the United States, HBCD was historically used as a flame retardant in the back coating of textiles.
Information gathered from research, industry and consumer product organizations, however, has led
EPA to believe that HBCD is no longer used in consumer textile applications outside of the auto
industry. EPA received information from a group of textile formulators that the end uses of HBCD-
containing textiles are for military, institutional and aviation applications, such as durable carpet tiles
for hospitals or prisons (U.S. EPA. 2012c; Friddle. 2011). Use in this application is quite small; in 2005,
only 1% of HBCD was used in textiles in the United States (U.S. EPA. 2012c). EPA finalized a SNUR in
2015 (U.S. EPA. 2015a) which requires persons who intend to manufacture (including import) or
process HBCD for use in consumer textiles (other than for use in motor vehicles) to notify EPA at least
90 days before commencing that activity. EPA has received no notifications since the rule became
effective in late 2015, and therefore does not expect HBCD to be used in consumer textiles except as
described in the SNUR. Articles containing HBCD manufactured previous to the finalization of the SNUR
may continue to be in service.
EPA found that a small amount of HBCD is used in floor mats, headliners and possibly other interior
fabrics in automobiles made or imported to the United States (U.S. EPA. 2012c). EPA, however,
received a public comment stating that HBCD is no longer used in automobile manufacturing and is
only present in replacement parts manufactured prior to date of the EPA HBCD Scoping Document
(public comment, EPA-HQ-QPPT-2016-0735-0027). Conversely, a different association of automakers
stated that HBCD may still be used by some non-member manufacturers in coatings of certain
components, such as dashboards and headliners, in solder paste in interior components such as
circuits, and in adhesives and foams (Public comment, EPA-HQ-QPPT-2016-0735-0015). A commenter
reports that HBCD is not used in the manufacturing process of any automotive components and that as
of 2015, members had "nearly phased out completely the use of HBCD" (Public comment, EPA-HQ-
QPPT-2016-0735-0014).
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Other Uses
The use of HBCD in other products is thought to be minor. In order to determine whether other uses
exist and to what extent, EPA reviewed state databases, product testing results and information from
foreign countries. The information is gathered in the "other commercial and consumer use" category.
The subcategories of reasonably foreseen other uses are listed in Table 2-3.
From June 2012 to March 2017, the use of HBCD in children's clothing, car seats, blankets, toys and toy
vehicles was reported 48 times to Washington State under state law (Public comment, EPA-HQ-OPPT-
2016-0735-0022). This information demonstrates that HBCD might be used in products intended for
children or that HBCD is a textile contaminant and may indicate the potential for widespread human
exposure to this flame retardant.
The Australian Department of Health and Aging reports that minimal amounts of HBCD are imported
into Australia already incorporated into various articles, such as inkjet printers, projectors, scanners,
ventilation units for offices, compact fluorescent lights and liquid-crystal display (LCD) digital
audiovisual systems (NICNAS. 2012). EPA/OPPT expects to consider these uses, however, it is currently,
unknown if HBCD is used in the United States for these purposes.
Table 2-3 summarizes each life cycle stage and the corresponding categories and subcategories of use
for HBCD that EPA expects to consider in the risk evaluation. Using the 2016 CDR, EPA identified
industrial processing or use activities, industrial function categories and commercial and consumer use
product categories. EPA identified the subcategories by supplementing CDR data with other published
literature and information obtained through stakeholder consultations. For risk evaluations, EPA
intends to consider each life cycle stage (and corresponding use categories and subcategories) and
assess relevant potential sources of release and human exposure associated with that life cycle stage.
Table 2-3. Categories and Subcategories of Conditions of Use for HBCD0	
Life Cycle Stage
Categorya
Subcategory b
References
Manufacture
Domestic Manufacture
Domestic Manufacture
U.S. EPA (2016b)
Import
Import
U.S. EPA (2016b)
Processing
Processing as
reactant/intermediate
Intermediate for all other
basic inorganic chemical
manufacturing
U.S. EPA (2016b)

Processing -
incorporated into
formulation, mixture or
reaction product
Flame retardants used in
plastic material and resin
manufacturing (e.g.,
manufacture of EPS resin
beads)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003: EINECS (2008):
Market Profile, EPA-
HQ-OPPT-2016-0735
Flame retardants used in
custom compounding of
purchased resin (e.g.,
compounding in XPS
masterbatch)
EINECS (2008)

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Life Cycle Stage
Categorya
Subcategory b
References


Flame retardants used in
adhesive
manufacturing (e.g.,
manufacture of solder
paste and other
adhesives)
Public Comment, EPA-
HQ-OPPT-2016-0735-
0008; Public
Comment, EPA-HQ-
OPPT-2016-0735-
0015
Flame retardants used in
paints and coatings
manufacturing (e.g.,
micronisation and
formulation of polymer-
based dispersions for
textile coatings)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735: EINECS (2008)
Incorporated into article
Flame retardants used in
plastics product
manufacturing
(manufacture of XPS and
EPS foam; manufacture
of structural insulated
panels (SIPS) from XPS
and EPS foam;
manufacture of HIPS;
manufacture of
electronics articles)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735: U.S. EPA
(2014b)
Flame retardants used in
textiles, apparel and
leather manufacturing
(e.g., coatings used at
textile and fabric
finishing mills, fabric
coating mills and carpet
and rug mills)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003: U.S. EPA
(2014a)
Flame retardants used in
transportation
equipment
manufacturing (e.g.,
manufacture of interior
components in
automobiles, including
fabrics, coatings, solder
paste, adhesives and
foams)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735; Public
Comment EPA-HQ-
OPPT-2016-0735-
0015
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Life Cycle Stage
Categorya
Subcategory b
References

Recycling
Recycling
Use Document, EPA-
HQ-OPPT-2016-0735-
0003
Distribution
Distribution
Distribution

Commercial/consumer
Use
Build ing/construction
materials
Plastic articles (hard):
construction and building
materials covering large
surface areas (e.g.,
EPS/XPS foam insulation
in residential, public and
commercial buildings,
and other structures)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003: U.S. EPA
(2016b): U.S. EPA
(2014b)

Electrical and electronic
products
Plastic articles (soft)
(e.g., wire and cable)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735: U.S. EPA
(2016b)
Plastic articles (hard)
(e.g., distribution boxes,
audio-visual equipment;
refrigerator lining;
computers; Inkjet
printers/scanners)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735: U.S. EPA
(2016b)
Floor coverings
Fabrics, textiles and
apparel (e.g., carpets and
rugs)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003:
Furniture and
furnishings
Fabrics, textiles and
apparel: Furniture and
furnishings, including
furniture coverings (e.g.,
institutional furniture)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003: U.S. EPA
(2015a)

Fabric, textile and
leather products d
Fabrics, textiles and
apparel (e.g., interior
fabrics for automobiles)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735
Textile finishing and
impregnating/surface
treatment products (e.g.,
other textile products)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Public
Comment, EPA-HQ-
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Life Cycle Stage
Categorya
Subcategory b
References



OPPT-2016-0735-
0022; Public
Comment, EPA-HQ-
OPPT-2016-0735-
0008
Other uses e
Other (e.g., bean bags,
product packaging, toys
and games, car seats;
children's clothing and
blankets, buoys for
aquaculture, compact
fluorescent lights,
ventilation units for
offices)
Use Document, EPA-
HQ-OPPT-2016-0735-
0003; Market Profile,
EPA-HQ-OPPT-2016-
0735; Public
Comment; EPA-HQ-
OPPT-2016-0735-
0022; Public
Comment, EPA-HQ-
OPPT-2016-0735-
0008; Public
Comment, EPA-HQ-
OPPT-2016-0735-
0015
Disposal
Emissions to air
Air
EINECS (2008)
Wastewater or liquid
wastes
Industrial pre-treatment
EINECS (2008)

Wastewater or liquid
wastes
Industrial wastewater
treatment
Publicly owned
treatment works (POTW)
Underground injection
Municipal landfill
Waste (solid and/or
liquid)
Hazardous landfill
Other land disposal
Municipal waste
incinerator
Hazardous waste
incinerator
Off-site waste transfer
Note: This table presents categories and subcategories of conditions of use that are based on the 2016 CDR industrial
function category and industrial sector descriptions and the OECD product and article category descriptions for the HBCD
uses identified. Clarification on the subcategories of use from the listed data sources are provided in parentheses.
a These categories of conditions of use appear in the Life Cycle Diagram, reflect CDR codes and broadly represent
conditions of use of HBCD in industrial and/or consumer settings.
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Life Cycle Stage
Category1
Subcategory1
References
bThese subcategories reflect more specific uses of HBCD.
c EPA assumes that the major use of HBCD is XPS and EPS foam used in building and construction materials, based on 2012
CDR data (U.S. EPA, 2016b). Other uses of HBCD not confirmed as ongoing uses may be minor or in some cases may be
historical uses.
d 2015 SNUR; (U.S. EPA, 2015a), EPA requires 90-day notification before manufacture or processing of HBCD in consumer
textiles, except those used in motor vehicles.
e Other uses in EPA's Market Report 2017 (U.S. EPA, 2017c) were identified from foreign studies and product testing
results, reporting by manufacturers to the state of Washington, and other sources. For the uses in other countries, it is
uncertain whether similar U.S. products contain HBCD. In some of the articles, HBCD is present but may not have been
intentionally used.
Recycling of EPS and XPS foam
To date, little is known by EPA about the recycling of products containing HBCD. Schlummer et al.
notes that EPS and XPS foam in construction insulation materials are rarely recycled for numerous
reasons, including that insulation waste is typically not separated from mixed waste stream and most
insulation containing HBCD is still in place. (Schlummer et al.) describe technologies available only on a
small scale to separate HBCD from insulation panels and recycle polystyrene.
Reuse and recycling is available in the United States for consumers through removal of insulation
during re-roofing projects. Two companies were identified that directly reuse (e.g., reuse without
reforming) XPS and EPS foam insulation and recycle (e.g., melting and inserting into the manufacturing
process).
•	Green Insulation Group: http://www.greeninsulationgroup.com/products/.
•	Nationwide Foam Recycling: http://nationwidefoam.com/what-vou-can-recycle.cfm.
Nationwide Foam Recycling, which is owned by Conigliaro Industries, Inc., indicate that their plant
recycles all EPS insulation and reuses all XPS insulation U.S. EPA (2017c). Once processed, their recycled
EPS roofing insulation is taken to polystyrene product manufacturers, notably picture frame
manufacturers, mostly in China but also in domestic markets. The company also delivers recycled
roofing material to other local EPS recycling plants that may use different processes. Nationwide Foam
Recycling processes 90,000 pounds/year of EPS standard packaging and 10,000 pounds/year of EPS
roofing material and estimated that 10-20% of EPS roofing material is recycled nationally. The company
also reuses XPS roofing material due the special equipment needed to recycle XPS and indicated that
XPS is rarely recycled in the United States. It was estimated that the majority (>50%) of XPS roofing
material is sent to landfills or waste energy plants. Processing estimates for XPS material were not
provided.
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 HBCD. Post-release pathways and routes will be
described to characterize the relationship or connection 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 HBCD.
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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 environmental receptors EPA expects to consider in the
risk evaluation. Table 2-4 provides environmental fate data that EPA has identified and considered in
developing the scope for HBCD.
Table 2-4. Environmental Fate Characteristics of HBCD
Property or Endpoint
Valuea
References
Direct photodegradation
Does not undergo direct photolysis
(estimated)
U.S. EPA (2015b)

Indirect photodegradation
2.1 days (air)
U.S. EPA (2015b)
Hydrolysis half-life
Does not undergo hydrolysis
U.S. EPA (2015b)
Biodegradation
0% in 28 days (aerobic in wastewater, OECD
301D)
63 days (aerobic soil, OECD 307)
7 days (anaerobic soil, OECD 308)
11-32 days (aerobic sediment, OECD 308)
1.1-1.5 days (anaerobic sediment, OECD 308)
0.66 days (anaerobic in sludge)
U.S. EPA (2015b)
Bioconcentration factor
(BCF)
8,974-18,100 (fish)
U.S. EPA (2015b)

Bioaccumulation factor
(BAF)
3,556,000 (estimated)
U.S. EPA (2012a)
Organic carbon:water
partition coefficient (log Koc)
4.9
U.S. EPA (2015b)

a Measured unless otherwise noted. Based on literature review described in U.S. EPA (2015b). Problem formulation
document https://www.eDa.gov/sites/Droduction/files/2015-09/documents/hbcd oroblem formulation.pdf.
The environmental fate of HBCD has previously been summarized in a number of other publications
(U.S. EPA. 2015b. 2014c: NICNAS. 2012: EC/HC. 2011: EINECS. 2008: U.S. EPA. 2008: OECD. 2007).
HBCD is persistent in environmental media. HBCD is expected to be stable to hydrolysis and direct
photolysis. Measured aerobic biodegradation half-lives range from months to greater than months.
Anaerobic biodegradation may be more rapid but in anaerobic conditions, degradation is also slow
with half-lives ranging to months or greater. HBCD is expected to sorb to particulates and sediments
and has limited mobility in soil. It is expected to have limited volatilization from soils and water
surfaces. In the atmosphere, HBCD is expected to occur primarily associated with particulates and may
undergo long-range transport. Particulate bound HBCD will be removed from the atmosphere by wet
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or dry deposition, and has an estimated vapor-phase half-life of 2.1 days for reaction with hydroxyl
radicals. HBCD is highly bioaccumulative with measured fish BCF values of 8,974-18,100.
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,
calculations based on empirical data and/or assumptions and models.
There may be releases of HBCD from industrial sites to wastewater treatment plants (WWTP), surface
water, air and landfill (U.S. EPA. 2015b). Sawing of EPS or XPS foam during commercial and consumer
use results in release of HBCD to the environment and emissions of HBCD from EPS and XPS foam and
wear of these products result in release of HBCD during their service life (U.S. EPA. 2015b). Disposal of
EPS and XPS foam may result in releases to the environment as a result of demolition of buildings or
material that is left on or in the soil (U.S. EPA. 2015b).
Articles that contain HBCD may release HBCD to the environment during use or through recycling and
disposal. Examples of HBCD releases that are more recently being explored in the literature include
release of HBCD from building materials through demolition (Duan et al.. 2016) and sorption of
suspended particles to clothing and transport down the drain during washing of textiles (Saini et al..
2016).
A source of information that EPA expects to consider in evaluating exposure are data reported under
the Toxics Release Inventory (TRI) program, however, TRI data are not yet available for HBCD. Under
the Emergency Planning and Community Right-to-Know Act (EPCRA) Section 313 rule, HBCD is a TRI-
reportable substance effective November 30, 2016. HBCD is reportable beginning with the 2017
calendar year and has been assigned a 100-pound reporting threshold. The first reporting forms from
facilities are due by July 1, 2018.
EPA expects to consider these data in conducting the exposure assessment component of the risk
evaluation for HBCD.
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 studies that measure environmental
concentrations or concentrations of chemical substances in biota provide evidence of exposure.
Monitoring and biomonitoring data were identified in EPA's data search for HBCD.
Environment
HBCD has been widely detected in both the environment and biota. When considering monitoring
studies reported in risk assessments completed to date and monitoring studies reported to open
literature, there are hundreds of studies that have reported HBCD in various media (see Systematic
Review Appendix; (NICNAS. 2012: EC/HC. 2011: EINECS. 2008).
HBCD has been detected in a wide variety of environmental media. Based on review of previously
completed assessments and EPA's problem formulation (U.S. EPA. 2015b). HBCD is expected to be
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present at relatively higher levels in sediment, soil and indoor dust. HBCD is also expected to be
present in ambient air, indoor air and surface water at relatively lower levels. Physical-chemical
properties influence the fate and transport of HBCD between media. For example, EPA expects to
consider partitioning of HBCD to sediment within the water column and to suspended particles and
dust in indoor environments (Law et al.. 2014). HBCD has also been detected in remote areas and in
very close proximity to industrial sources and many sampling locations in between (Law et al.. 2014).
EPA expects to consider and review readily available environmental monitoring data in the risk
evaluation.
Biota
HBCD has the potential to both persist and bioaccumulate in the environment (UNEP. 2010). Once
HBCD is present in the environment, it is available for uptake by a variety of species, including humans.
HBCD has been detected in human milk, adipose tissue, blood and hair. HBCD has been detected in
invertebrates, fish, birds, mammals and plants. HBCD is also present in edible fish, plants, milk and
other food sources, and there are existing studies that quantify potential dietary exposures (NICNAS.
2012; EC/HC. 2011; EINECS. 2008). EPA expects to consider and review readily available biomonitoring
data in the risk evaluation.
2.3.4	Environmental Exposures
The manufacturing, processing, distribution, use and disposal of HBCD can result in releases the
environment. EPA expects to consider exposures to the environment and ecological receptors that
occur via the exposure pathways or media shown in Figure 2-4a and Figure 2-4b in conducting the risk
evaluation for HBCD.
2.3.5	Human Exposures
EPA expects to consider three broad categories of human exposures: occupational exposures,
consumer exposures and general population exposures. Subpopulations within these exposure
categories will also be considered as described herein.
2.3.5.1 Occupational Exposures
EPA expects to consider worker activities where there is a potential for exposure under the various
conditions of use described in Section 2.2. In addition, EPA expects to consider exposure to
occupational non-users, who do not directly handle the chemical but perform work in an area where
the chemical is present. When data and information are available to support the analysis, EPA also
expects to consider the effect(s) that engineering controls and/or personal protective equipment have
on occupational exposure levels.
EPA anticipates inhalation of dust and other respirable particles (for example, resulting from
particulate generated by hot wire cutting of EPS or XPS foam) as the most important HBCD exposure
pathway for workers and occupational non-users (U.S. EPA. 2015b; NICNAS. 2012; ECHA. 2009; EINECS.
2008); however, dermal exposure, including skin contact with liquids and solids, may also occur when
performing certain work activities.
Workers and occupational non-users may be exposed to HBCD when performing activities associated
with the conditions of use described in Section 2.2, including, but not limited to:
•	Loading and transferring HBCD powder from process vessels to sacks or bags.
•	Applying formulations containing HBCD onto substrates (e.g., textile coatings).
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•	Handling, transporting and disposing waste containing HBCD.
•	Performing other work activities in or near areas where HBCD is used.
•	Cutting EPS or XPS foam (e.g., at constructions sites).
Based on these activities, EPA expects to consider inhalation exposure to particulates and dermal
exposure, including skin contact with particulates for workers and occupational non-users. EPA also
expects to consider potential worker exposure via the oral route such as from incidental ingestion of
HBCD residue on hand/body or through particulates that deposit in the upper respiratory tract.
Occupational exposure limits for HBCD have not been established by the Occupational Safety and
Health Administration (OSHA), the American Conference of Government Industrial Hygienists (ACGIH),
or the National Institute of Occupational Safety and Health (NIOSH).
https://www.ncbi.nlm.nih.gov/books/NBK225635/
2.3.5.2 Consumer Exposures
HBCD may be found in consumer products and articles and/or commercial products and articles that
are available for public purchase at common retailers (EPA-HQ-OPPT-2016-0735-0003. Sections 3
and 4, (U.S. EPA. 2017b)) and can therefore result in exposures to consumers.
Exposure routes for consumers using HBCD-containing products may include inhalation of particulates
or emitted vapor, dermal exposure due to contact with articles and ingestion of settled dust and
mouthing of articles.
Consumer exposure to articles containing HBCD is somewhat different from consumer exposure to a
product where the chemical is consumed during its use and then discarded (for example, a can of spray
paint). HBCD is incorporated into articles that may be present during the entire useful life of the article
in microenvironments where consumers may be continually exposed until disposal of the article.
HBCD-containing articles (e.g., insulation, electronics products, plastic based products and textiles)
have relatively long service lives in comparison to other consumer products that are quickly used and
discarded. Indoor environments with elevated levels of HBCD in indoor air and dust may contain some
combination of articles containing HBCD.
Consumer exposure to HBCD may include inhalation exposure related to emissions of HBCD from
articles. Indoor air concentrations may vary by infiltration from ambient air or emissions associated
with presence of articles. Emission from articles will vary based on the surface area of the article
present in the building, the weight fraction of HBCD and building characteristics such as air exchange
and inter-zonal air flow. Based on the relatively high octanol:air partition coefficient (Koa) and relatively
low vapor pressure, HBCD emitted to indoor air is likely to partition to suspended particles and
potentially settle to dust rather than be emitted in its vapor phase.
Consumer exposure to HBCD may include oral exposure related to mouthing of articles and objects
containing HBCD. Exposures related to the mouthing of objects are influenced by the migration rate of
the chemical from the material into saliva, the duration of contact time for mouthing, and the
prevalence/likelihood of the article being mouthed. EPA expects to consider these factors in
developing exposure estimates from mouthing.
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Consumer exposure to HBCD may include dermal exposure related to direct skin contact with articles
containing HBCD. However, there are several factors to be considered and this is likely a relatively
minor pathway compared to dermal contact with dust. The contact duration, solubility and diffusivity
of HBCD within different articles, and contact surface area of skin all influence potential exposures
(EINECS. 2008).
There may be some consumers who may have greater exposure potential to HBCD such as:
•	Children or adults who spend time in microenvironments with elevated dust or indoor air
concentrations due to presence of multiple article which contain elevated levels of HBCD.
•	Children or adults who have elevated contact time, due to mouthing and/or dermal contact,
with multiple articles containing HBCD.
EPA expects to consider inhalation, dermal and oral exposures to consumers and bystanders associated
with the consumer use in the home.
2.3.5.3 General Population Exposures
Wastewater/liquid wastes, solid wastes or air emissions of HBCD could result in potential pathways for
oral, dermal or inhalation exposure to the general population. EPA expects to consider each media,
route and pathway to estimate general population exposures.
Inhalation
There is the potential for inhalation exposure to HBCD by breathing ambient air and indoor air.
Ambient air concentrations may vary by proximity to an industrial source, while indoor air
concentrations are discussed in the consumer exposure section. Based on the relatively high Koa and
relatively low vapor pressure, HBCD is expected to be present primarily in suspended particles in the
air rather than in the vapor phase.
Based on these potential sources and pathways of exposure, EPA expects to consider inhalation
exposures of the general population to air/particulates containing HBCD that may result from the
conditions of use of HBCD.
Oral
The general population may ingest HBCD via a variety of exposure pathways.
There is potential for oral exposure to HBCD by ingestion of dust and soil; drinking water and breast
milk; and edible aquatic and terrestrial biota (e.g., from fishing, hunting, gathering and farming). There
is a wide range of dust and soil monitoring data available. Dust concentrations vary widely across
different microenvironments and within microenvironments and are generally reported in the ng/g or
Hg/g range (U.S. EPA. 2015b). Existing exposure assessments outside of the United States have
quantified dietary exposure from a variety of food sources and compared these values to other
pathways (EC/HC. 2011; EINECS. 2008). Exposures from drinking water containing HBCD are possible,
but are likely to be relatively lower than other oral exposure pathways (EC/HC. 2011; EINECS. 2008).
Based on these potential sources and pathways of exposure, EPA expects to consider oral exposures to
the general population that may result from the conditions of use of HBCD.
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Dermal
There is potential for dermal exposure to HBCD through contact with dust and soil containing HBCD.
Dermal exposure is likely to vary based on the contact time with the material, the concentration of
HBCD and properties of HBCD that influence the chance of dermal absorption (EINECS. 2008).
Based on these potential sources and pathways of exposure, EPA expects to consider dermal exposures
to the general population that may result from the conditions of use of HBCD.
2.3.5.4 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 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.
Of the human receptors identified in the previous sections, EPA identifies the following as potentially
exposed or susceptible subpopulations due to their greater exposure, that EPA expects to consider in
the risk evaluation:
•	Workers and occupational non-users.
•	Consumers and bystanders associated with consumer use. HBCD 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 that result in
releases to the environment and subsequent exposures (e.g., individuals who live or work near
manufacturing, processing, distribution, use or disposal sites).
There are some reasonably likely exposure scenarios where greater exposure from multiple sources
may occur. There may be some individuals who have greater potential for exposure to HBCD such as:
•	Children who spend time in microenvironments with elevated dust concentrations.
•	Breast-fed infants where concentrations of breast milk containing HBCD are elevated.
•	Children or adults who ingest soil or sediment in environments where HBCD concentrations are
elevated.
•	Adults who have elevated intake rates of edible aquatic biota or terrestrial biota containing
elevated levels of HBCD.
In developing scenarios, EPA will evaluate available data to ascertain whether some human receptor
groups may be exposed via exposure pathways that may be distinct to a particular subpopulation or
lifestage (e.g., children's crawling, mouthing or hand-to-mouth behaviors) and whether some human
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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 (U.S. EPA. 2006).
In summary, in the risk evaluation for HBCD, EPA expects to consider the following potentially exposed
groups of human receptors: workers, occupational non-users, consumers, bystanders associated with
consumer use. As described above, 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 HBCD, as described in
Strategy for Conducting Literature Searches for HBCD: Supplemental File for the TSCA Scope Document
(EPA-HQ-QPPT-2016-0735). Based on initial screening, EPA expects to consider the hazards of HBCD
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 identified in the scope will be
considered for every exposure scenario.
2.4.1	Environmental Hazards
For scoping purposes, EPA consulted the following sources of environmental hazard data for HBCD:
U.S. EPA (2016c): U.S. EPA(2014d): NICNAS (2012): EC/HC(2011): UNEP (2010): U.S. EPA (2010):
EINECS (2008): OECD (2007). However, EPA also expects to consider other studies (e.g., more recently
published, alternative test data) that have been published since these reviews, as identified in the
literature search conducted by the Agency for HBCD [HBCD (CASRN 25637-99-4, 3194-55-6, 3194-57-8)
Bibliography: Supplemental File for the TSCA Scope Document, EPA-HQ-QPPT-2016-07351.
EPA expects to consider the hazards of HBCD to aquatic organisms including fish, aquatic invertebrates,
aquatic plants and sediment invertebrates exposed to relevant media under acute and chronic
exposure conditions. Based on the assessments mentioned above, there was acute toxicity to aquatic
invertebrates from HBCD, based on mortality and immobilization. Chronic toxicity to aquatic
invertebrates (growth and reproduction) was observed when exposed to HBCD. Chronic toxicity was
observed in sediment dwelling organisms based on reduced survivability when exposed to HBCD.
EPA expects to consider the hazards of HBCD to terrestrial organisms including soil invertebrates and
avian species exposed to relevant media under acute and chronic exposure conditions. Based on
previous assessments, chronic toxicity to terrestrial invertebrates (reproduction) was observed when
exposed to HBCD. Also, toxicity to avian species was observed, based on reduced hatchability and
survival, when exposed to HBCD.
2.4.2	Human Health Hazards
The human health hazard of HBCD has been examined in several publications (U.S. EPA. 2016c. 2014b.
d; NICNAS. 2012: EC/HC. 2011: EINECS. 2008: U.S. EPA. 2008: OECD. 2007).
HBCD does not have an existing EPA IRIS Assessment; however, as part of a coordinated agency effort,
the TRI Technical Review of HBCD (U.S. EPA. 2016c). 2015 HBCD Problem Formulation and Initial
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Assessment (PFIA) (U.S. EPA. 2015b). and Preliminary Materials for the IRIS Toxicological Review of
HBCD (U.S. EPA. 2014d) compiled and reviewed non-cancer health hazards of HBCD, including: acute
toxicity, liver toxicity, thyroid toxicity, reproductive/developmental toxicity, neurotoxicity,
immunotoxicity, sensitization and irritation. EPA has relied heavily on this comprehensive review in
preparing this scope. EPA also expects to consider other studies (e.g., more recently published,
alternative test data) that have been published since this review, as identified in the literature search
conducted by the Agency for HBCD [HBCD (CASRN 25637-99-4, 3194-55-6, 3194-57-8) Bibliography:
Supplemental File for the TSCA Scope Document, EPA-HQ-QPPT-2016-07351. EPA expects to consider all
potential hazards associated with HBCD. Based on reasonably available information, the following are
the hazards that have been identified in previous government documents and that EPA currently
expects will likely be the focus of its analysis.
2.4.2.1 Non-Cancer Hazards
Acute Toxicity
Animal studies have observed potential neurological effects and clinical signs of toxicity including death
following high-dose acute administration of HBCD (U.S. EPA. 2015b).
Liver Toxicity
Increased liver weight has been observed in multiple laboratory animal studies, in both sexes, across
species and following both adult and developmental exposures. In mice, HBCD exposure induced
evidence of inflammatory changes in the liver and hepatic fatty changes (steatosis) in animals with a
high-fat diet (U.S. EPA. 2014d).
Thyroid Toxicity
Human epidemiological studies have reported potential effects of HBCD on thyroid hormones. Animal
toxicity studies provide stronger evidence of thyroid perturbation associated with HBCD exposure,
including altered levels of thyroid hormones, histological changes and increased thyroid weight, with
effects observed across multiple lifestages, sexes, species and exposure durations (U.S. EPA. 2014d).
Reproductive/Developmental Toxicity
For female reproductive effects, there is some rodent evidence that HBCD may alter fertility and
pregnancy outcomes as well as reduce the number of mature and developing follicles in the ovary;
however, effects on reproductive organ weight are inconsistent. For male reproductive effects, there is
some epidemiological support of an association between HBCD exposure and altered serum
testosterone and sex hormone binding globulin (SHGB) levels; however, animal studies did not report
any effects on male reproductive organ weights, reproductive development, hormone concentrations
or spermatogenic measures. There is mixed epidemiological data on developmental toxicity of HBCD,
while animal toxicity studies suggest that early life exposure to HBCD at high doses can affect various
developmental outcomes, including reduced offspring viability, decrements in pup weight and
alterations in eye opening (U.S. EPA. 2014d).
Neurotoxicity
There is an absence of a strong association in epidemiological studies between HBCD exposure and
developmental neurotoxicity in various neuropsychological domains; however, there is evidence of
potential developmental neurotoxicity in rodents. Perinatal HBCD exposure was shown to alter
neurodevelopmental milestones while eliciting changes in locomotor activity and executive function
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that persisted into adulthood. HBCD exposure also appears to affect other neurological endpoints
related to changes in auditory sensitivity, dopamine system function and brain weight in multiple
studies. Effects on neurodevelopmental endpoints were observed in both sexes and across a wide
range of doses and exposure durations. However, there is currently not any substantial evidence to
support concern for neurotoxicity during when exposure is limited to adulthood (U.S. EPA. 2014d).
Immunotoxicity
The effects of HBCD on both functional and structural immune endpoints have been evaluated in
animal models. Overall, immunological effects from HBCD exposure are variable and inconsistent
across studies for endpoints such as immune organ weights, hematology or histopathology (U.S. EPA.
2014d). and its relevance to the risk evaluation will require further evaluation.
Sensitization/lrritation
There is limited information available suggesting potential mild irritation and sensitizing potential of
HBCD (U.S. EPA. 2015b).
2.4.2.2	Genotoxicity and Cancer Hazards
Available data suggest that HBCD is not genotoxic. Existing assessments have also concluded, based on
genotoxicity information and a limited lifetime study, that HBCD is not carcinogenic (NICNAS. 2012;
EINECS. 2008: TemaNord. 2008: OECD. 2007).
Unless new information indicates otherwise, EPA does not expect to conduct additional in-depth
analysis of genotoxicity or cancer hazards in the risk evaluation of HBCD at this time. Consistent with
the discussion in the preamble to the risk evaluation rule, Procedures for Chemical Risk Evaluation
Under the Amended Toxic Substances Control Act (TSCA), pertaining to conditions of use, EPA does not
believe it makes sense to expend Agency resources evaluating hazards that EPA is confident are not
presented by a chemical substance.
2.4.2.3	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 evaluate available data to ascertain whether some human
receptor groups may have greater susceptibility than the general population to the chemical's
hazard(s).
2.5 Initial Conceptual Models
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. As part of the scope for
HBCD, EPA developed three conceptual models, presented here.
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2.5.1 Initial Conceptual Model for Industrial and Commercial Activities and Uses:
Potential Exposures and Hazards
Figure 2-2 presents the initial conceptual model for human receptors from industrial and commercial
uses of HBCD. EPA expects that workers and occupational non-users may be exposed to HBCD via
inhalation, dermal and oral routes. EPA anticipates inhalation of dust containing HBCD to be an
important exposure route (U.S. EPA. 2015b). Dermal exposure may occur as a result of handling HBCD
in certain conditions of use such as formulation of polymer dispersions or handling of particulate solids
(OECD. 2015; EINECS. 2008). Oral exposure of workers to HBCD may occur through ingestion of dust
that deposits in the upper respiratory tract and is swallowed or via incidental ingestion of HBCD
following hand and body contact.
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INDUSTRIAL AND COMMERCIAL	EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORS"	HAZARDS
ACTIVITIES / USES»
Manufacture
Processing:
•As reactant/intermediate
"Incorporated into
formulation, mixture, or
reaction product
•Incorporated into article
o EPS/XPS, HIPS,
Textilesc
Liquid Contact
Solid Contact
Hazards Potentially Associated with
Acute and/or Chronic Exposures
See Section 2.4.2
Workers e.
Occupational
Non-Users
Oral
Fugitive
Dust
Emissions b
Indoor Air
Recycling
Inhalation
Electrical and Electronic
Products
Outdoor Air
(see Figs 2-4a and 2-4b
for EmissionstoAir)
Floor Coverings
Stack Dust
—| Emissionsb
Furniture and Furnishings
Fa brie. Textile, and
Leather Productsc
Other Products
(e.g., product packaging,
children's products)
Dust emissions from
product installation,
reuse, and demolition.
Bu i Id i ng/Construction
Materials
Workers e.
Occupational
Non-Users
Waste Handling,
Treatment and Disposal
Liquid Contact, Solid
Contact, Dust
Dermal, Oral,
Inhalation
Wastewater, Solid Wastes, Air Emissions
(see Figures 2-4a and 2-4b)
Figure 2-2. Initial HBCD 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 HBCD.
aSome products are used in both commercial and consumer applications. Additional uses of HBCD are included in Table 2-3.
b Stack air emissions are emissions that occur through stacks, confined vents, ducts, pipes or other confined air streams. Fugitive air emissions are those that are not
stack emissions, and include fugitive equipment leaks from valves, pump seals, flanges, compressors, sampling connections and open-ended lines; evaporative losses
from surface impoundment and spills; and releases from building ventilation systems.
c SNUR: EPA requires 90-day notification before manufacture or processing of HBCD in consumer textiles, except those used in motor vehicles.
d Receptors include potentially exposed or susceptible subpopulations.
e 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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2.5.2 Initial Conceptual Model for Consumer Activities and Uses: Potential
Exposures and Hazards
Figure 2-3 presents the initial conceptual model for human receptors from consumer uses of HBCD.
EPA expects that consumers and bystanders may be exposed via inhalation related to emissions of
HBCD from articles, oral exposure related to mouthing of articles and objects containing HBCD and
incidental ingestion of settled dust containing HBCD. Exposure to HBCD may also potentially include
dermal exposure related to direct skin contact with articles containing HBCD. It should be noted that
some consumers may purchase and use products primarily intended for commercial use.
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CONSUMER ACTIVITIES / USES a	EXPOSURE PATHWAY	EXPOSURE ROUTE	RECEPTORSd	HAZARDS
Building/Construction
Materials
(e.g., building panels)
Electrical and Electronic
Products
Floor Coverings
Furniture and Furnishings
Oral
Mouthing
^ Consumers/ >
General Population;
v Bystanders >
Hazards Potentially Associated with
Acute and/or Chronic Exposures
See Section 2.4.2
Fabric, Textile, and
Leather Products'"
Dermal
Indoor Air, Settled Dust
Inhalation
Other Products'
(e.g., product packaging,
children's products)
Consumer Handling and
Disposal of Waste
Solid, Liquid Contact
Figure 2-3. Initial HBCD Conceptual Model for Consumer Activities and Uses: Potential Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes and hazards to human receptors from consumer activities and
uses of HBCD.
8Some products are used in both commercial and consumer applications. Additional uses of HBCD are included in Table 2-3.
b SNUR: EPA requires 90-day notification before manufacture or processing of HBCD in consumer textiles, except those used in motor vehicles.
c Prevalence of use is unknown; some data are from product testing.
d Receptors include potentially exposed or susceptible subpopulations.
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2.5.3 Initial Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards
As shown in Figure 2-4a, EPA anticipates that the general population living near industrial and
commercial facilities using or disposing of HBCD may be exposed via several pathways. As HBCD is
persistent and bioaccumulative, releases to air, water or land from industrial or commercial activities
are expected to result in exposures to human receptors via ingestion of water, breast milk and edible
aquatic and terrestrial biota (e.g., from fishing, hunting, gathering, farming). Inhalation may also be
anticipated for the general population if releases to air occur, although the exposure may vary
depending upon the proximity to the industrial source. Dermal routes of exposure are also possible.
Releases of HBCD to air, water or land from industrial or commercial activities may result in exposure
to aquatic and terrestrial life via contaminated water, sediment or soil as shown in
Figure 2-4b.
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RELEASES AND WASTES FROM
INDUSTRIAL / COMMERCIAL / CONSUMER USES
EXPOSURE PATHWAY
EXPOSURE ROUTE
RECEPTORS c
HAZARDS
Direct
discharge
Water
Sediment
Indirect discharge
Biosolids
Soil
General
Population
Waste Transport
Air
Oral
Breast Milk
Dermal
Inhalation
POTW
Emissions to Air
Terrestrial
Biota
Recycling, Other
Treatment b
Off-site Waste
Transfer
Underground
Injection
Wastewater
or Liquid Waste
Incinerators
(Municipals
Hazardous Waste)
Industrial Pre-
Treatment or
Industrial WWT
Solid Wastes
Liquid Waste
Drinking Water
Aquatic Biota
Municipal,
Hazardous Landfill
or Other Land
Disposal
Hazards Potentially Associated with
Acute and/or Chronic Exposures
See Section 2.4.2
Figure 2-4a. Initial HBCD Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes and hazards to human receptors from releases and wastes from
industrial and commercial uses of HBCD,
a Industrial wastewater or liquid wastes may be treated on-site and then released to surface water (direct discharge), or pre-treated and released to POTW (indirect
discharge). For consumer uses, such wastes may be released directly to POTW (i.e., down the drain). Drinking water will undergo further treatment in drinking water
treatment plant. Ground water may also be a source of drinking water.
b Additional releases may occur from recycling and other waste treatment.
c Receptors include potentially exposed or susceptible subpopulations.
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RELEASES AND WASTES FROM	EXPOSURE PATHWAY	RECEPTORS0	HAZARDS
INDUSTRIAL / COMMERCIAL / CONSUMER USES
Direct
discharge
Water8
Sediment
Aquatic
Species
Indirect
discharge
Biosolids
Terrestrial
Species
Soil
Waste Transport
Air
POTW
Emissions to Air
Underground
Injection
Recycling, Other
Treatmentb
Off-site Waste
Transfer
Wastewater
or Liquid Waste
Incinerators
(Municipal &
Hazardous Waste)
Industrial Pre-
Treatmentor
Industrial WWT
Liquid Waste
Solid Wastes
Municipal,
Hazardous Landfill
or Other Land
Disposal
Hazards Potentially Associated
with Acute and/or Chronic
Exposures
See Section 2.4.1
Figure 2-4b. Initial HBCD Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards
The conceptual model presents the exposure pathways and hazards for environmental receptors from industrial and commercial uses of
HBCD.
a Industrial wastewater or liquid wastes may be treated on-site and then released to surface water (direct discharge), or pre-treated and released to POTW (indirect
discharge). For consumer uses, such wastes may be released directly to POTW (i.e., down the drain). Drinking water will undergo further treatment in drinking water
treatment plant. Ground water may also be a source of drinking water.
b Additional releases may occur from recycling and other waste treatment,
c Receptors include potentially exposed or susceptible subpopulations.
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2.6 Initial Analysis Plan
The initial analysis plan will be used to develop the eventual problem formulation and final analysis
plan for the risk evaluation. While EPA has conducted a search for readily available data and
information from public sources as described in Section 1.3, EPA encourages submission of additional
existing data, such as full 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.
The analysis plan outlined here is based on the conditions of use of HBCD, as described in Section 2.2
of this scope. The analysis plan may be refined as EPA proceeds with the systematic review of the
information in the HBCD (CASRN 25637-99-4, 3194-55-6, 3194-57-8) Bibliography: Supplemental File
for the TSCA Scope Document, (EPA-HQ-QPPT-2016-0735). EPA will be evaluating the weight of the
scientific evidence for both hazard and exposure. Consistent with this approach, EPA will also use a
systematic review approach. As such, EPA will use explicit, pre-specified criteria and approaches to
identify, select, assess, and summarize the findings of studies. This approach will help to ensure that
the review is complete, unbiased, reproducible, and transparent.
2.6.1 Exposure
2.6.1.1	Environmental Releases
EPA expects to consider and analyze releases to environmental media as follows:
1)	Review reasonably available published literature or information on processes and activities
associated with the conditions of use to evaluate the types of releases and wastes generated.
2)	Review reasonably available chemical-specific release data, including measured or estimated
release data (e.g., data collected under the TRI and National Emissions Inventory [NEI]
programs).
3)	Review reasonably available measured or estimated release data for surrogate chemicals that
have similar uses, volatility, chemical and physical properties.
4)	Understand and consider regulatory limits that may inform estimation of environmental
releases.
5)	Review and determine applicability of OECD Emission Scenario Documents (ESDs) and EPA
Generic Scenarios to estimation of environmental releases.
6)	Evaluate the weight of the evidence of environmental release data.
7)	Map or group each condition(s) of use to a release assessment scenario.
2.6.1.2	Environmental Fate
EPA expects to consider and analyze fate and transport in environmental media as follows:
1)	Review reasonably available measured or estimated environmental fate endpoint data
collected through the literature search.
2)	Using measured data and/or modeling, determine the influence of environmental fate
endpoints (e.g., persistence, bioaccumulation, partitioning, transport) on exposure pathways
and routes of exposure to human and environmental receptors.
3)	Evaluate the weight of the evidence of environmental fate data.
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2.6.1.3	Environmental Exposures
EPA expects to consider the following in developing its environmental exposure assessment of HBCD:
1)	Review reasonably available environmental and biological monitoring data for all media
relevant to environmental exposure.
2)	Review reasonably available information on releases to determine how modeled estimates of
concentrations near industrial point sources compare with available monitoring data. Available
exposure models will be evaluated and considered alongside available monitoring data to
characterize environmental exposures. Modeling approaches to estimate surface water
concentrations, sediment concentrations and soil concentrations generally consider the
following inputs: release into the media of interest, fate and transport and characteristics of the
environment.
3)	Review reasonably available biomonitoring data. Consider whether these monitoring data could
be used to compare with species or taxa-specific toxicological benchmarks.
4)	Determine applicability of existing additional contextualizing information for any monitored
data or modeled estimates during risk evaluation. Review and characterize the spatial and
temporal variability, to extent data are available, and characterize exposed aquatic and
terrestrial populations.
5)	Evaluate the weight of evidence of environmental occurrence data and modeled estimates.
6)	Map or group each condition(s) of use to environmental assessment scenario(s).
2.6.1.4	Occupational Exposures
EPA expects to consider and analyze both worker and occupational non-user exposures as follows:
1)	Review reasonably available exposure monitoring data for specific condition(s) of use. Exposure
data to be reviewed may include workplace monitoring data collected by government agencies
such as the Occupational Safety and Health Administration (OSHA) and the National Institute of
Occupational Safety and Health (NIOSH), and monitoring data found in published literature
(e.g., personal exposure monitoring data (direct measurements) and area monitoring data
(indirect measurements).
2)	Review reasonably available exposure data for surrogate chemicals that have uses, volatility
and chemical and physical properties similar to HBCD.
3)	For conditions of use where data are limited or not available, review existing exposure models
that may be applicable in estimating exposure levels.
4)	Review reasonably available data that may be used in developing, adapting or applying
exposure models to the particular risk evaluation.
5)	Consider and incorporate applicable engineering controls and/or personal protective
equipment into exposure scenarios.
6)	Evaluate the weight of the evidence of occupational exposure data.
7)	Map or group each condition of use to occupational exposure assessment scenario(s).
2.6.1.5	Consumer Exposures
EPA expects to consider and analyze both consumers using a consumer product and bystanders
associated with the consumer using the product as follows:
1)	Review reasonably available consumer product-specific exposure data related to consumer
uses/exposures.
2)	Evaluate the weight of the evidence of consumer exposure data.
3)	For exposure pathways where data are not available, review existing exposure models that may
be applicable in estimating exposure levels.
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4)	Review reasonably available data that may be used in developing, adapting or applying
exposure models to the particular risk evaluation. For example, existing models developed for a
chemical assessment may be applicable to another chemical assessment if model parameter
data are available.
5)	Review reasonably available consumer product-specific sources to determine how those
exposure estimates compare with those reported in monitoring data.
6)	Review reasonably available population- or subpopulation-specific exposure factors and activity
patterns to determine if potentially exposed or susceptible subpopulations need be further
refined.
7)	Map or group each condition of use to consumer exposure assessment scenario(s).
2.6.1.6 General Population
EPA expects to consider and analyze general population exposures as follows:
1)	Review available environmental and biological monitoring data for media to which general
population exposures are expected. For exposure pathways where data is not available, review
existing exposure models that may be applicable in estimating exposure levels.
2)	Consider and incorporate applicable media-specific regulations into exposure scenarios or
modeling.
3)	Review reasonably available data that may be used in developing, adapting or applying
exposure models to the particular risk evaluation. For example, existing models developed for a
chemical assessment may be applicable to another chemical assessment if model parameter
data are available.
4)	Review reasonably available information on releases to determine how modeled estimates of
concentrations near industrial point sources compare with available monitoring data.
5)	Review reasonably available population- or subpopulation-specific exposure factors and activity
patterns to determine if potentially exposed or susceptible subpopulations need to be further
defined.
6)	Evaluate the weight of the evidence of general population exposure data.
7)	Map or group each condition of use to general population exposure assessment scenario(s).
2.6.2 Hazards (Effects)
2.6.2.1 Environmental Hazards
EPA will conduct an environmental hazard assessment of HBCD as follows:
1)	Review available environmental hazard data, including data from alternative test methods (e.g.,
computational toxicology and bioinformatics; high-throughput screening methods; data on
categories and read-across; in vitro studies).
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.
3)	Derive concentrations of concern (COC) for all identified ecological endpoints.
4)	Evaluate the weight of the evidence of environmental hazard data.
5)	Consider the route(s) of exposure, available biomonitoring data and available approaches to
integrate exposure and hazard assessments.
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2.6.2.2 Human Health Hazards
EPA expects to consider and analyze human health hazards as follows:
1)	Review reasonably available human health hazard data, including data from alternative test
methods (e.g., computational toxicology and bioinformatics; high-throughput screening
methods; data on categories and read-across; in vitro studies; systems biology).
2)	In evaluating reasonably available data, determine whether particular human receptor groups
may have greater susceptibility to the chemical's hazard(s) than the general population.
3)	Conduct hazard identification (the qualitative process of identifying non-cancer and cancer
endpoints) and dose-response assessment (the quantitative relationship between hazard and
exposure) for all identified human health hazard endpoints.
4)	Derive points of departure (PODs) where appropriate; conduct benchmark dose modeling
depending on the available data. Adjust the PODs as appropriate to conform (e.g., adjust for
duration of exposure) to the specific exposure scenarios evaluated.
5)	Evaluate the weight of the evidence of human health hazard data.
6)	Consider the route(s) of exposure (oral, inhalation, dermal), available route-to-route
extrapolation approaches, available biomonitoring data and available approaches to correlate
internal and external exposures to integrate exposure and hazard assessment.
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 (U.S. EPA. 2000). As defined EPA's Risk Characterization Policy, "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) (U.S. EPA. 2000). EPA will also
present information in this section consistent with approaches described in the Risk Evaluation
Framework Rule.
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http://chm.pops.int/Convention/POPsReviewCommittee/hrPOPRCMeetings/POPRC5/POPRC5F
ollowupcommunications/HBCDInvitationforcommentsondraftRP/tabid/742/language/en-
US/Default.aspx.
Weil. ED; Levchik. SV. (2009). Flame retardants for plastics and textiles practical applications, [online]:
Carl Hanser Verlag GmbH & Co. KG.
XPSA (Extruded Polystyrene Foam Association). (2017). Preliminary information on manufacturing,
processing, distribution, use, and disposal: Cyclic aliphatic bromide cluster (HBCD). OCSPP.
Public comment. (EPA-HQ-OPPT-2016-0735-0017).
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APPENDICES
Appendix A REGULATORY HISTORY
The chemical substance, HBCD, is subject to federal and state laws and regulations in the United
States. The federal laws and regulations applicable to HBCD are listed along with the regulating
agencies below in Table_Apx A-l. States also regulate HBCD through state laws and regulations, which
are also listed within this section in Table_Apx A-2.
A.l Federal Laws and Regulations
Table_Apx A-l. Federal Laws and Regulations
Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
Toxic Substances
Control Act (TSCA) -
Section 5(a)
Once EPA determines that a use of a chemical
substance is a significant new use under TSCA
section 5(a), persons are required to submit a
significant new use notice (SNUN) to EPA at least
90 days before they manufacture (including
import) or process the chemical substance for
that use.
In September 2015, EPA
promulgated a SNUR to
designate manufacture or
processing of HBCD for use
as a flame retardant in
consumer textiles (apart
from use in motor
vehicles) as a significant
new use. Manufacturers
(which includes importers)
and processors are
required to notify EPA
90 days before
commencing the activity
(80 FR 57293, September
23, 2015).
TSCA - Section 6(b)
EPA directed to identify and begin risk
evaluations on 10 chemical substances drawn
from the 2014 update of the TSCA Work Plan for
Chemical Assessments.
Cyclic Aliphatic Bromide
Cluster (HBCD) is on the
initial list of chemicals to
be evaluated for
unreasonable risk under
TSCA (81 FR 91927,
December 19, 2016).
TSCA - Section 8(a)
The TSCA section 8(a) CDR Rule requires
manufacturers (including importers) to give EPA
basic exposure-related information on the types,
quantities and uses of chemical substances
produced domestically and imported into the
United States.
HBCD manufacturing
(including importing),
processing, and use
information is reported
under the CDR rule (76 FR
50816, August 16, 2011)
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Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
TSCA - Section 8(b)
EPA must compile, keep current and publish a
list (the TSCA Inventory) of each chemical
substance manufactured, processed or imported
into the United States.
HBCD (CASRN 25637-99-4
and CASRN 3194-55-6) was
on the initial TSCA
Inventory and therefore
was not subject to EPA's
new chemicals review
process (60 FR 16309,
March 29, 1995).
Emergency Planning
and Community Right-
to-Know Act (EPCRA) -
Section 313
Requires annual reporting from facilities in
specific industry sectors that employ 10 or more
full-time equivalent employees and that
manufacture, process or otherwise use a TRI-
listed chemical in quantities above threshold
levels.
EPA listed HBCD on the TRI
under 81 FR 85440
effective November 28,
2016. The first TRI
reporting deadline for
HBCD is July 1, 2018.
A.2 State Laws and Regulations
Table_Apx A-2. State Laws and Regulations
State Actions
Description of Action
Chemical of High
Concern to Children
Maine classifies HBCD as a chemical of high concern (Maine 38 M.R.S.A. §
1693-A(1))
Minnesota classifies HBCD as a chemical of high concern (Toxic Free Kids
Act Minn. Stat. 2010 116.9401-116.9407)
Washington requires manufacturers of children's products sold in
Washington to report if their product contains certain chemicals of high
concern to children, including HBCD. The law also bans from manufacture
or sale, in the state, children's products or residential upholstered
furniture containing >1,000 ppm of five flame retardants, including HBCD
(Wash. Admin. Code § 173-334-130)
Other
In California, HBCD is listed as an initial informational candidate under
California's Safer Consumer Products regulations, on the state's
Proposition 65 list (Cal. Code Regs, tit. 22, § 69502.3, subd. (a))
California lists HBCD as a designated priority chemical for biomonitoring.
However, California has not yet started biomonitoring HBCD. (California SB
1379)
The Oregon Department of Environmental Quality lists HBCD as a priority
persistent pollutant and publishes use, exposure pathways and release
data for HBCD (Oregon SB 737)
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A.3 International Laws and Regulations
Table_Apx A-3. Regulatory Actions by other Governments and Tribes
Country/Organization
Requirements and Restrictions
Canada
In October 2016, the Regulations Amending the Prohibition of Certain
Toxic Substances Regulations, 2012 (the Amendments) were published in
the Canada Gazette, Part II: Vol. 150, No. 20 - October 5, 2016 and will
come into force in December 2016. The Amendments include controls on
HBCD that prohibit HBCD and certain products containing the substance.
Time-limited exemptions for certain uses are included to allow industry to
phase-out their use of HBCD. (Government of Canada)
European Union
HBCD is listed as a substance of very high concern (SVHC) and it is also
listed under Annex XIV (Authorisation list) of European Union's
Registration, Evaluation, Authorisation and Restriction of Chemicals
(REACH). After August 21, 2015, only persons with approved authorization
applications mav continue to use the chemical (European Chemicals
Agency)
The Waste Electrical and Electronic Equipment (WEEE) directive in the
European Union requires the separation of plastics containing brominated
flame retardants prior to recycling (European Commission WEEE).
Japan
HBCD is subject to mandatory reporting requirements in Japan under the
Chemical Substances Control Law (CSCL); specifically, Japan requires type
III monitoring for all substances that may interfere with the survival and/or
growth of flora and fauna (Ministry of Economy, Trade and Industry Japan).
Stockholm Convention
on POPs
In May 2013, HBCD was added to the United Nation's Stockholm
Convention list of POPs. The chemical is scheduled to be eliminated by
November 2014 with specific exemptions for production and uses in
expanded or XPS building insulation. As required by the convention, parties
that use these exemptions must register with the secretariat and the
exemptions will expire in November 2019 (Stockholm Convention POPs).
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Appendix B PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE
INFORMATION
This appendix provides information and data found in preliminary data gathering for HBCD.
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.l Manufacture (Including Import)
B.l.1.1 Domestic Manufacture
HBCD is manufactured in a closed system through the bromination of cyclododecatriene (CDT) in a
suitable solvent at a process temperature of 20-70°C. The product of the reaction is a mixture of three
principal HBCD isomers: alpha, beta and gamma. The resulting suspension is filtered, the solvent
removed and the product dried. HBCD is produced in powder or pellet form (EINECS. 2008; Suh. 2000).
B.l.1.2 Import
EPA has also not identified specific activities related to the import of HBCD at this time. EPA anticipates
that imported chemicals are often stored in warehouses prior to distribution for further processing and
use. In some cases, the chemicals may be repackaged into differently sized containers, depending on
customer demand, and quality control (QC) samples may be taken for analyses.
B.1.2 Processing and Distribution
B.1.2.1 Processing as a Reactant/Intermediate
Processing as a reactant or intermediate describes the use of HBCD in a chemical reaction where the
chemical is consumed in the manufacture of another chemical substance. HBCD is an intermediate in
the inorganic chemicals manufacturing industry (U.S. EPA. 2016b).
B.1.2.2 Incorporated into a Formulation, Mixture or Reaction Product
Incorporation into a formulation, mixture or reaction product refers to the process of mixing or
blending of several raw materials to obtain a single product or preparation. HBCD may undergo several
processing steps and the processing is dependent on its downstream incorporation into articles, which
is discussed in the next subsection. EPA identified the following processing activities for HBCD.
Compounding into XPS Masterbatch
HBCD is compounded into an XPS masterbatch prior to being sold to XPS plastic converters, who then
convert the XPS into a final article. Compounding likely occurs in a partially open process using
extruders. In extruders, blends of polymer, additives and/or masterbatch are mixed either in the
hopper or in tumblers and then fed into an extruder comprising one or two screws. These both shear
the material and transport it through a heating regime. Volatile emissions may be produced and these
are vented at various points in the extruder barrel (OECD. 2004). The compounded masterbatch may
be converted into a final extrudate; however, EPA expects that the masterbatch is sent to industrial
customers for further processing into a final article. HBCD concentration in the masterbatch is
expected to be 50-70% (EINECS. 2008).
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Manufacture of EPS Resin Beads
Manufacture of EPS resin beads is a batch process that involves suspension polymerization of styrene
in water. Styrene is dispersed in water in the form of small droplets. Prior to combining the water with
the organic phase, additives are introduced. Typically, these include suspension agents, free-radical-
forming initiators and HBCD. HBCD, most often delivered in 25-kg paper bags with a plastic liner, is
suspended at low temperatures in styrene prior to the addition of the water phase. Normally, the bags
are emptied into an intermediate storage container from which the HBCD is transported via pipes and
a weighing station prior the addition to the styrene (EINECS. 2008).
Within the monomer droplets (bulk), polymerization occurs while the reactor content is heated up and
held at its reaction temperature. During this free-radical polymerization an expansion agent (e.g.,
pentane) is added to the reactor under pressure, where it is absorbed in the polymer droplets. In the
final EPS beads, HBCD is incorporated as an integral and encapsulated component within the polymer
matrix with uniform concentration throughout the bead. After complete conversion of the styrene
monomer to EPS-beads, the reactor is cooled down and the beads are separated from the water by
centrifugation. The decanted water, which could contain dissolved and dispersed HBCD, is reused and
exchanged on an annual basis or less frequently. The EPS beads are dried, and thereafter classified into
various size fractions and surface coated. These different grades are packed in bins or bags or
transported in bulk trucks to the EPS-converters. The maximum concentration of HBCD in EPS beads is
assumed to be 0.7% (EINECS. 2008).
Micronisation and Formulation for Textile Coatings
In textile coatings, there is sometimes a need for micronisation of the HBCD powder to produce an
extra fine powder. Micronisation involves the grinding or milling of HBCD into particles that are
3-4 micrometers in particle size. Once the particle size is ideal, HBCD is further formulated into
polymer-based dispersions. For the textile finishing industry, the dispersions are water-based and
typically carried out in an open batch system. HBCD is added to a dispersion containing water, a
polymer (such as latex, acrylates or polyvinylchloride [PVC]), a thickener and a dispersion agent
(EINECS. 2008). Micronisation may occur in ball blenders, mills or other types of grinding processes.
Coatings may also be formulated through a plastic processing and conversion step. These processes are
described in OECD's ESDs on Plastic Additives (OECD. 2004).
Several ESDs published by OECD and Generic Scenarios published by EPA have been identified that may
provide general process descriptions for other formulation processes that may be used for HBCD in
adhesives, paint coatings and textile coatings. The processes involved are expected to be similar to
those described above for polymer-based dispersions and may involve the unloading of HBCD powder
from transport packaging directly into mixing equipment or into intermediate storage vessels, mixing
of components either a batch or continuous system, QC sampling and final packaging of the
formulation into containers.
B.l.2.3 Incorporated into an Article
Incorporation into an article typically refers to a process in which a chemical becomes an integral
component of an article (as defined at 40 CFR 704.3) for distribution in commerce. Exact process
operations involved in the incorporation of HBCD-containing formulations or reaction products are
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dependent on the article. EPA identified the following processing activities that incorporate HBCD and
HBCD formulations or reaction products into articles.
EPS resin beads are converted into EPS products by expansion and then molding into rigid closed-cell
foam. Once expanded, the beads are fused in a steam heated mold to form a specific shape or can be
formed in a billet or block that can be hot-wire cut to its desired shape and size by users (Priddy. 2006).
HBCD powder or granules are incorporated into XPS products by extrusion. The HBCD powder or
granules are unloaded into a hopper and fed into an extruder along with polystyrene resin, a blowing
agent and other ingredients. A viscous plastic fluid is formed in the extruder and is discharged under
pressure through a die onto a moving belt at ambient conditions. The blowing agent vaporizes, causing
the polymer to expand into a desired shape or form, most likely continuous sheets (boards) of closed
cell insulation. Alternatively, a vacuum is used in addition to the blowing agent to cause polymer
expansion. XPS masterbatch is similarly converted into XPS products (NICNAS. 2012; EINECS. 2008; Suh.
2000).
HBCD may also be used in the manufacture of HIPS materials that may be used in electrical and
electronic products, as described in Section 2.2.2. HIPS materials are made by incorporating rubber
among other additives (such as HBCD) into polystyrene to impart increased toughness. HIPS pellets,
HBCD powder or granules and other ingredients are pre-mixed and fed to the extrusion equipment.
(EINECS. 2008; Priddy. 2006). An alternative route for HIPS production is via an intermediate-
compounding process in which general purpose HBCD-containing polystyrene masterbatch is prepared,
followed by compounding this masterbatch with virgin HIPS material in a conversion step.
B.l.2.4 Recycling
As stated in Section 2.2.2, EPS and XPS foam in construction insulation materials is rarely recycled for
numerous reasons, including that insulation waste is typically not separated from mixed waste stream.
However, reuse and recycle does occur in the United States. At the end-of-life, polystyrene insulation
boards (i.e., EPS and XPS foam insulation containing HBCD) may still have beneficial value for
insulation. The insulation can be removed in whole and reused in the same capacity. Polystyrene
insulation may also be demolished, melted and reformed into new insulation materials boards or other
applications. Typically, polystyrene insulation containing HBCD can only be recycled into building
insulation or other building applications (U.S. EPA. 2014b).
Electronic products (which may or may not contain HBCD) can also be recycled. HIPS materials
constitute more than half the plastic materials recovered from household electronics (Borchardt.
2006). No information was identified that further described the processes used in recovering the
plastics from electronics and how those plastics are reprocessed into other products.
B.1.3 Uses
B.1.3.1 Building/Construction Materials
A major use of HBCD is in XPS and EPS foam for continuous insulation applications such as in walls and
roofs on the exterior of buildings, ceilings and subfloor systems. The materials may be incorporated
into building products such as SIPS or insulating concrete forms (ICFs) or used in other below grade or
geotechnical applications for foundations or highways or for dimensional stability or strength
applications (e.g., insulated cold storage applications) (U.S. EPA. 2017c. 2014b; NICNAS. 2012).
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B.l.3.2 Electrical and Electronic Products
A reasonably foreseen minor use of HBCD is use as a flame retardant in the manufacture of electrical
and electronic products. As discussed in Section 2.2.2, HBCD may be used in HIPS materials which in
turn would be used in the assembly of electrical and electronic appliances such television sets, audio-
visual equipment and refrigerator lining and would also be used in some wire and cable applications.
B.l.3.3 Floor Coverings
A reasonably foreseen minor use of HBCD is use as a flame retardant in the manufacture of floor
coverings. As discussed in Section 2.2.2, HBCD may be used as a flame retardant in textile coatings for
military, institutional and aviation applications, such as durable carpet tiles for hospitals or prisons.
B.1.3.4 Furniture and Furnishings
A reasonably foreseen minor use of HBCD is use as a flame retardant in the manufacture of furniture
and furnishings. As discussed in Section 2.2.2, HBCD is used as a flame retardant in textile coatings for
the manufacture of institutional furniture coverings.
B.l.3.5 Fabric, Textile and Leather Products
HBCD has minor uses in the manufacture of fabrics and textiles. As discussed in Section 2.2.2, HBCD is
used as a flame retardant in coatings applied to automobile interior components (e.g., headliner,
dashboard).
B.l.3.6 Other Products
A variety of other uses may exist for HBCD, including use in food packaging, bean bags, product
packaging, toys, car seats, clothing, children's products, buoys for aquaculture, compact fluorescent
bulbs and ventilations units. HBCD may also have minor uses in latex binders and paints (EPA-HQ-
QPPT-2017-0735-0003) (U.S. EPA. 2017b: NICNAS. 2012: EC/HC. 2011).
It is unclear at this time the total volume of HBCD used in any of these applications. EPA has not
identified any information to further refine the use of HBCD in these products; although, the use
volume is likely minimal. More information on these uses will be gathered through expanded literature
searches in subsequent phases of the risk evaluation process.
B.1.4 Disposal
Releases from industrial sites to surface water (via direct discharge or indirect discharge through
POTWs), air and landfill are expected during manufacture, processing, use, improper handling,
improper storage or containment, product usage and disposal of HBCD or products containing HBCD
(U.S. EPA. 2014b: NICNAS. 2012: EC/HC. 2011: EINECS. 2008). Textile-related releases during product
use are suspected of having a significant share of the total HBCD released into the environment
(EINECS. 2008).
Demolished building materials are classified as Construction and Demolition (C&D) waste, which may
be disposed in municipal solid waste landfills (MSWLFs) or C&D landfills (U.S. EPA. 2014b). Other
products containing HBCD may also be disposed in MSWLFs. Also, as stated in Section 2.2.2, XPS foam
may also be disposed of via waste energy plants.
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