EPA Document# EPA-D-20-0001
April 2020
United States	Office of Chemical Safety and
Ml	Environmental Protection Agency	Pollution Prevention
Draft Scope of the Risk Evaluation for
0-Dichlorobenzene
CASRN 95-50-1
April 2020

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TABLE OF CONTENTS
ACKNOWLEDGEMENTS	5
ABBREVIATIONS AND ACRONYMS	6
EXECUTIVE SUMMARY	10
1	INTRODUCTION	13
2	SCOPE OF THE EVALUATION	13
2.1	Reasonably Available Information	13
2.1.1	Search of Gray Literature												14
2.1.2	Search of Literature from Publicly Available Databases (Peer-reviewed Literature)			 15
2.1.3	Search of TSCA Submissions		20
2.2	Conditions of Use	21
2.2.1	Categories and Subcategories of Conditions of Use Included in the Scope of the Risk
Evaluation.....																				 22
2.2.2	Activities Excluded from the Scope of the Risk Evaluation							23
2.2.3	Production Volume...............................................					24
2.2.4	Overview of Conditions of Use and Lifecycle Diagram					24
2.3	Exposures	27
2.3.1	Physical and Chemical Properties 										27
2.3.2	Environmental Fate and Transport								 27
2.3.3	Release to the Environment............................											27
2.3.4	Environmental Exposures.												 29
2.3.5	Occupational Exposures 				..................................................				 29
2.3.6	Consumer Exposures																30
2.3.7	General Population Exposures.....															31
2.4	Hazards (Effects)	31
2.4.1	Environmental Hazards																		 31
2.4.2	Human Health Hazards													 31
2.5	Potentially Exposed or Susceptible Subpopulations	32
2.6	Conceptual Models	32
2.6.1	Conceptual Model for Industrial and Commercial Activities and Uses: Potential Exposures
and Hazards															 33
2.6.2	Conceptual Model for Consumer Activities and Uses 										35
2.6.3	Conceptual Model for Environmental Releases and Wastes: Potential Exposures and
Hazards (Regulatory Overlay)............											37
2.6.3.1	Drinking W ater Pathway	39
2.6.3.2	Ambient Water Pathway	39
2.6.3.3	Disposal and Soil Pathways	40
2.6.4	Conceptual Model for Environmental Releases and Wastes: Potential Exposures and
Hazards										 41
2.7	Analysis Plan	43
2.7.1	Physical and Chemical Properties and Environmental Fate						43
2.7.2	Exposure																44
2.7.2.1 Environmental Releases	44
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2.7.2.2	Environmental Exposures	46
2.7.2.3	Occupational Exposures	47
2.7.2.4	Consumer Exposures	49
2.7.2.5	General Population	50
2.7.3	Hazards (Effects)																	 53
2.7.3.1	Environmental Hazards	53
2.7.3.2	Human Health Hazards	54
2.7.4	Summary of Risk Approaches for Characterization...........						 56
2.8 Peer Review	57
REFERENCES	58
APPENDICES	66
Appendix A LIST OF GRAY LITERATURE SOURCES............					66
Appendix B PHYSICAL AND CHEMICAL PROPERTIES OF o-DICHLOROBENZENE............. 70
Appendix C ENVIRONMENTAL FATE AND TRANSPORT PROPERTIES OF o-
DICHLOROBENZENE.													 72
Appendix D REGULATORY HISTORY..								 74
D.l Federal Laws and Regulations																74
D.2 State Laws and Regulations												80
D.3	International Laws and Regulations.					...................81
Appendix E PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE INFORMATION...		 83
E.l	Process Information.,..													83
E. 1.1 Manufacture (Including Import)	83
E.2 Processing and Distribution											84
E.2.1 Processing as a Reactant or Intermediate	84
E.2.2 Incorporated into a Formulation, Mixture or Reaction Product	84
E.3 Uses[[[								85
E.3.1 Ink, Toner, and Colorant Products	85
E.3.2 Coatings and paints, thinners, paint removers	85
E.3.3 Lubricants and oils	85
E.3.4 Air Care Products	86
E.3.5 Other uses	86
E.4 Disposal....																		86
E.5 Preliminary Occupational Exposure Data...........									87
Appendix F SUPPORTING INFORMATION - Conceptual Model for Industrial and Commercial
Activities and Uses:									89
Appendix G SUPPORTING i INFORMATION - CONCEPTUAL MODEL FOR CONSUMER
ACTIVITIES AND I "SES												 99

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LIST OF TABLES
Table 2-1. Results of Title Screening of Submissions to EPA under Various Sections of TSCAa	21
Table 2-2. Categories and Subcategories of Conditions of Use Included in the Scope of the Risk
Evaluation	22
Table 2-3. Summary of o-Dichlorobenzene TRI Production-Related Waste Managed in 2018	28
Table 2-4. Summary of Releases of o-Dichlorobenzene to the Environment During 2018	29
LIST OF FIGURES
Figure 2-1. Gray Literature Tags by Discipline for o-Dichlorobenzene	15
Figure 2-2. Peer-Reviewed Literature- Physical-Chemical Properties Search Results for	16
Figure 2-3. Peer-reviewed Literature - Fate Search Results for o-Dichlorobenzene	17
Figure 2-4. Peer-reviewed Literature - Engineering Search Results for o-Dichlorobenzene	18
Figure 2-5. Peer-reviewed Exposure Search Results for o-Dichlorobenzene	19
Figure 2-6. Peer-reviewed Hazard Search Results for o-Dichlorobenzene	20
Figure 2-7. o-Dichlorobenzene Life Cycle Diagram	26
Figure 2-8. o-Dichlorobenzene Conceptual Model for Industrial and Commercial Activities and Uses:
Worker and Occupational Non-User Exposures and Hazards	34
Figure 2-9. o-Dichlorobenzene Conceptual Model for Consumer Activities and Uses: Consumer
Exposures and Hazards	36
Figure 2-10. o-Dichlorobenzene Conceptual Model for Environmental Releases and Wastes:
Environmental and General Population Exposures and Hazards (Regulatory Overlay) ..38
Figure 2-11. o-Dichlorobenzene Conceptual Model for Environmental Releases and Wastes:
Environmental and General Population Exposures and Hazards	42
LIST OF APPENDIX TABLES
TableApx A-l. Gray Literature Sources That Yielded Results for o-Dichlorobenzene	66
TableApx B-l. Physical and Chemical properties of o-Dichlorobenzene	70
Table_Apx D-l. Federal Laws and Regulations	74
Table_Apx D-2. State Laws and Regulations	80
Table Apx D-3. Regulatory Actions by other Governments, Tribes, and International Agreements	81
Table Apx E-l. Summary of NIOSH HHEs with Monitoring for o-Dichlorobenzene a	87
Table Apx F-l. Worker and Occupational Non-User Exposure Conceptual Model Supporting Table.. 89
Table Apx G-l. Consumer Exposure Conceptual Model Supporting Table	99
Table Apx H-l. Environmental Exposure Conceptual Model Supporting Table	103
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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 Intra-agency
reviewers that included multiple offices within EPA, Inter-agency reviewers that included
multiple Federal agencies, and assistance from EPA contractors Abt Associates (Contract No.
EP-W-16-009), GDIT (Contract No. HHSN316201200013W), ERG (Contract No. EP-W-12-
006), ICF (Contract No. 68HERC19D0003), SRC (Contract No. 68HERH19D0022), and Versar
(Contract No. EP-W-17-006). EPA also acknowledges the contributions of technical experts
from EPA's Office of Research and Development.
Docket
Supporting information can be found in public docket: EPA-HQ-OPPT-2018-0444.
Disclaimer
Reference herein to any specific commercial products, process or service by trade name,
trademark, manufacturer or otherwise does not constitute or imply its endorsement,
recommendation or favoring by the United States Government.

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ABBREVIATIONS AND ACRONYMS
|ig	Microgram(s)
AAL
Allowable Ambient Levels
AC
Acute concentration
ACGIH
American Conference of Government Industrial Hygienists
ADME
Absorption, Distribution, Metabolism, and Excretion
Apx
Appendix
AT SDR
Agency for Toxic Substances and Disease Registry
AUC
Area Under the Curve
AWQC
Ambient Water Quality Criteria
BAF
Bioaccumulation Factor
BCF
Bioconcentration Factor
BW3/4
Body weight scaling to the 3/4 power
CAA
Clean Air Act
CARB
California Air Resources Board
CASRN
Chemical Abstracts Service Registry Number
CBI
Confidential Business Information
CCD
Chemical Control Division
CCL
Contaminant Candidate List
CDC
Centers for Disease Control
CDR
Chemical Data Reporting
CEHD
Chemical Exposure Health Data
CERCLA
Comprehensive Environmental Response, Compensation and Liability Act
CESSD
Chemistry, Economics and Sustainable Strategies Division
CFR
Code of Federal Regulations
ChemSTEER
Chemical Screening Tool for Exposure and Environmental Releases
COC
Concentration of Concern
CoRAP
Community Rolling Action Plan
COU
Conditions of Use
CPCat
Chemical and Product Categories
CPID
Consumer Product Information Database
CSCL
Chemical Substances Control Law
DHHS
Department of Health and Human Services
DMR
Discharge Monitoring Report
DNA
Deoxyribonucleic Acid
EC
Engineering controls
ECOTOX
ECOTOXicology knowledgebase
ED
Exposure duration
E-FAST
Exposure and Fate Assessment Screening Tool
E-FAST2
Exposure and Fate Assessment Screening Tool version 2
EPA
Environmental Protection Agency
EPCRA
Emergency Planning and Community Right-to-Know Act
EPI Suite™
Estimation Program Interface Suite™
EPS
Expanded Polystyrene
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ERG
Eastern Research Group, Inc.
ESD
Emission Scenario Document
EU
European Union
FDA
Food and Drug Administration
FF
Far field
g/L
Gram(s) per Liter
HERO
Health and Environmental Research Online
Hg
Mercury
HHE
Health Hazard Evaluation
HMTA
Hazardous Materials Transportation Act
HPV
High Production Volume
HQ
Headquarters
HSDB
Hazardous Substances Data Bank
HUC
Hydrologic Unit Code
IA
Indoor air
IARC
International Agency for Research on Cancer
IECCU
Indoor Environmental Concentrations in Buildings with Conditioned and

Unconditioned Zones
IMIS
Integrated Management Information System
K
Thousand
kg
Kilogram(s)
km
Kilometer(s)
L
Liter(s)
lb
Pound
LC50
Lethal Concentration of 50% test organisms
LEV
Local exhaust ventilation
LOAEL
Lowest Observed Adverse Effect Level
LOEC
Lowest Observed Effect Concentration
m
Meter(s)
m3
Cubic Meter(s)
MACT
Maximum Achievable Control Technology
MCL
Maximum Contaminant Level
MCLG
Maximum Contaminant Level Goal
mg
Milligram(s)
mg/kg-bw
Milligram(s) per kilogram body weight
mg/L
Milligram(s) per Liter
mg/m3
Milligram(s) per cubic meter
mg/mL
Milligram(s) per milliliter
mmHg
Millimeter(s) of Mercury
MOA
Mode of Action
MOE
Margin of exposure
MRL
Minimal Risk Level
n
number
N/A
Not Applicable
NHANES
National Health and Nutrition Examination Survey
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NICNAS
National Industrial Chemicals Notification and Assessment Scheme
(Australia)

NIH
National Institutes of Health
NIOSH
National Institute for Occupational Safety and Health
NITE
National Institute of Technology and Evaluation
NOAEL
No Observed Adverse Effect Level
NOEC
No Observed Effect Concentration
NPDES
National Pollutant Discharge Elimination System
NPDWR
National Primary Drinking Water Regulations
NPL
National Priorities List
NPRI
National Pollutant Release Inventory
NR
Not Reported
NRC
National Research Council
NSPS
New Source Performance Standards
NTP
National Toxicology Program
NWIS
National Water Information System
OCSPP
Office of Chemical Safety and Pollution Prevention
OECD
Organisation for Economic Co-operation and Development
OEHHA
Office of Environmental Health Hazard Assessment (California)
OEL
Occupational Exposure Limit
OES
Occupational Exposure Scenario
OLEM
Office of Land and Emergency Management
ONU
Occupational Non-User
OPPT
Office of Pollution Prevention and Toxics
ORD
Office of Research and Development
OSHA
Occupational Safety and Health Administration
OST
Office of Science and Technology
OSWER
Office of Solid Waste and Emergency Response
OW
Office of Water
P
Persistence
P-Chem
Physical Chemical Properties
PBPK
Physiologically Based Pharmacokinetic
PBT
Persistent, Bioaccumulative, Toxic
PECO
Population, Exposure, Comparator and Outcome
PEL
Permissible Exposure Limit
PESS
Potentially Exposed or Susceptible Subpopulation
POD
Point of Departure
POTW
Publicly Owned Treatment Works
ppb
Part(s) per billion
PPE
Personal Protective Equipment
ppm
Part(s) per million
PS
Point Source
PV
Production Volume
PWS
Public Water System
QA
Quality Assurance

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QC
Quality Control
QSAR
Quantitative Structure Activity Relationship
RA
Risk Assessment
RAD
Risk Assessment Division
RCRA
Resource Conservation and Recovery Act
REACH
Registration, Evaluation, Authorisation and Restriction of Chemicals
(European Union)

REL
Recommended Exposure Limit
RfC
Reference Concentration
RfD
Reference dose
RQ
Risk Quotient
SAB
Science Advisory Board
SACC
Science Advisory Committee on Chemicals
SAR
Structure-activity relationship
SARA
Superfund Amendments and Reauthorization Act
SD
Standard deviation
SDS
Safety Data Sheet
SDWA
Safe Drinking Water Act
SIC
Standard Industrial Classification
SIDS
Screening Information Dataset
STEL
Short-term Exposure Limit
STORET
STORage and RETrieval (water quality data warehouse)
SVOC
Semivolatile Organic Compounds
SWC
Surface Water Concentration
T
Toxic (used with PBT)
TIAB
Title and Abstract
TLV
Threshold Limit Value
TRI
Toxics Release Inventory
TSCA
Toxic Substances Control Act
TTO
Total Toxic Organics
TWA
Time-weighted average
U.S.
United States
U.S.C.
United States Code
UCMR
Unregulated Contaminant Monitoring Rule
UIC
Underground Injection Control
US EPA
United States Environmental Protection Agency
USGS
United States Geological Survey
VOC
Volatile Organic Compound
VP
Vapor Pressure
WQP
Water Quality Portal
WQX
Water Quality Exchange
WWT
Wastewater Treatment
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EXECUTIVE SUMMARY
In December 2019, EPA designated o-dichlorobenzene (CASRN 95-50-1) as a high-priority
substance for risk evaluation following the prioritization process as required by section 6(b) of
the Toxic Substances Control Act (TSCA) and implementing regulations ( K Part 702)
(Docket ID: EPA-HQ-OPPT-2018-0444). The first step of the risk evaluation process is the
development of the scope document and this document fulfills the TSCA regulatory requirement
to issue a draft scope document as described in 40 CFR 70^ 7). The draft scope for o-
dichlorobenzene includes the following information: the conditions of use, potentially exposed or
susceptible subpopulations (PESS), hazards, and exposures that EPA plans to consider in this
risk evaluation, along with a description of the reasonably available information, conceptual
model, analysis plan and science approaches, and plan for peer review for this chemical
substance. EPA is providing a 45-day comment period on the draft scope. Comments received on
this draft scope document will help inform development of the final scope document and the risk
evaluation.
General Information. o-Dichlorobenzene is a colorless, volatile liquid that is poorly soluble in
water but miscible with most organic solvents. It has a total production volume in the United
States between 100,000 and 500,000 pounds.
Reasonably Available Information. EPA leveraged the data and information sources already
described in the document supporting the High Priority Substance designation for o-
dichlorobenzene to inform the development of this draft scope document. Furthermore, EPA
conducted a comprehensive search to identify and screen multiple evidence streams (i.e.,
chemistry, fate, release and engineering, exposure, hazard) and the search and screening results
are provided in Section 2.1. EPA is seeking public comment on this draft scope document and
will consider additional information identified following publication of this draft scope
document, as appropriate, in developing the final scope document. EPA is using the systematic
review process described in the Application of Systematic Review in TSCA Risk Evaluations
document (U.S. EPA. 2018a) to guide the process of searching for and screening reasonably
available information, including information already in EPA's possession, for inclusion in the
risk evaluation. EPA is applying these systematic review methods to collect reasonably available
information regarding the hazards, exposures, PESS, and conditions of use that may help inform
the risk evaluation for o-dichlorobenzene.
Conditions of Use. EPA plans to evaluate manufacturing (including importing), processing,
distribution in commerce, commercial and consumer uses, and disposal of o-dichlorobenzene in
the risk evaluation. o-Dichlorobenzene is manufactured (including imported) in the U.S. The
chemical is processed as a reactant and incorporated into formulation, mixture, or reaction
products. Several commercial uses were identified that ranged from use in lubricant and
degreaser products to use in inks and paint strippers. Consumer uses were reported in lubricant
and degreaser products, air care products, and other uses such as ceramics glazing and cleaning
products. EPA identified these conditions of use from information reported to EPA through
Chemical Data Reporting (CDR) and Toxics Release Inventory (TRI) reporting, published
literature, public comments, and consultation with stakeholders for both uses currently in
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production and uses whose production may have ceased. EPA is aware of information reporting
use of o-dichlorobenzene in pesticides; however, they are not conditions of use for the chemical
substance as defined in TSCA § 3(2) and (4). Section 2.2 provides details about the conditions of
use within the scope of the risk evaluation.
Conceptual Model. The conceptual models for o-dichlorobenzene are presented in Section 2.6.
Conceptual models are graphical depictions of the actual or predicted relationships of conditions
of use, exposure pathways (e.g., media), exposure routes (e.g., inhalation, dermal, oral), hazards
and receptors throughout the life cycle of the chemical substance. EPA proposes to focus the risk
evaluation for o-dichlorobenzene on the following exposures, hazards and receptors however,
EPA also plans to consider comments received on this draft scope and other reasonably available
information when finalizing this scope document, and to adjust the exposure pathways, exposure
routes and hazards included in the scope document as needed.
• Exposures (Pathways and Routes), Receptors and PESS. EPA plans to evaluate both
human and environmental exposures and releases to the environment resulting from the
conditions of use of o-dichlorobenzene that EPA plans to consider in risk evaluation.
Exposures for o-dichlorobenzene are discussed in Section 2.3. Additional information
gathered through the results of systematic review searches will also informed expected
exposures.
EPA's plan as to evaluating environmental exposure pathways in the draft scope
document considers whether and how other EPA administered statues and regulatory
programs address the presence of o-dichlorobenzene in media pathways falling under the
jurisdiction of those authorities. Section 2.6.3. discusses those pathways that may be
addressed pursuant to other Federal laws. In Section 2.6.4, EPA presents the conceptual
model describing the identified exposures (pathways and routes), receptors and hazards
associated with the conditions of use of o-dichlorobenzene within the scope of the risk
evaluation.
Preliminarily, EPA plans to evaluate the following human and environmental exposure
pathways, routes, receptors and PESS in the scope of the risk evaluation. However, EPA
plans to consider comments received on this draft scope and other reasonably available
information when finalizing this scope document, and to adjust the exposure pathways,
exposure routes and hazards included in the scope document as needed.:
-	Occupational exposure pathways associated with industrial and commercial
conditions of use: EPA plans to evaluate exposures to workers and/or
occupational non-users via the inhalation route and exposures to workers via the
dermal route associated with manufacturing, processing, industrial/commercial
use, and disposal of o-dichlorobenzene.
-	Consumer and bystander exposure pathways associated with consumer conditions
of use: EPA plans to evaluate the inhalation and dermal exposure to o-
dichlorobenzene when consumers are using lubricants and greases, air care and
other products.
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-	General population pathways: EPA plans to evaluate exposure to o-
dichlorobenzene via groundwater, ambient air, and fish ingestion for the general
population via the oral, inhalation and dermal routes.
-	Receptors andPESS: EPA plans to include children, women of reproductive age
(e.g., pregnant women per TSCA statute), workers and consumers as receptors
and PESS in the risk evaluation.
-	Environmental exposure pathways: EPA plans to evaluate exposure to o-
dichlorobenzene for aquatic and terrestrial receptors (biota).
Hazards. Hazards for o-dichlorobenzene are discussed in section 2.4. EPA completed
preliminary reviews of information from peer-reviewed assessments and databases to identify
potential environmental and human health hazards for o-dichlorobenzene as part of the
prioritization process. Environmental hazard effects were identified for aquatic and terrestrial
organisms. Information collected through systematic review methods and public comments may
identify additional environmental hazards that warrant inclusion in the environmental hazard
assessment of the risk evaluation.
EPA plans to use systematic review methods to evaluate the epidemiological and toxicological
literature for o-dichlorobenzene. Relevant mechanistic evidence will also be considered, if
reasonably available, to inform the interpretation of findings related to potential human health
effects and the dose-repose assessment. EPA plans to evaluate all of the potential human health
hazards for o-dichlorobenzene identified in Section 2.4.2. The broad health effect categories
include reproductive and developmental, immunological, nervous system, genotoxicity,
carcinogenicity and absorption, distribution, metabolism, and excretion (ADME).
Analysis Plan. The analysis plan for o-dichlorobenzene is presented in Section 2.7. The analysis
plan outlines the general science approaches that EPA plans to consider use for the various
evidence streams (i.e., chemistry, fate, release and engineering, exposure, hazard) supporting the
risk evaluation. The analysis plan is based on EPA's knowledge of o-dichlorobenzene to date
which includes a partial, but ongoing, review of identified information as described in Section
2.1. EPA plans to continue to consider new information submitted by the public. Should
additional data or approaches become reasonably available, EPA may update its analysis plan in
the final scope document.
EPA plans to seek public comments on the systematic review methods supporting the risk
evaluation of o-dichlorobenzene including the methods for assessing the quality of data and
information and the approach for evidence synthesis and evidence integration supporting the
exposure and hazard assessments. The details will be provided in a supplemental document that
EPA anticipates releasing for public comment prior to finalization of the scope document.
Peer Review. The draft risk evaluation for o-dichlorobenzene will be peer reviewed. Peer review
will be conducted in accordance with relevant and applicable methods for chemical risk
evaluations, including using EPA's Peer Review Handbook and other methods consistent with
section 26 of TSCA (See 40 CFR 702.45Y
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1 INTRODUCTION
This document presents for comment the scope of the risk evaluation to be conducted for o-
dichlorobenzene under the Frank R. Lautenberg Chemical Safety for the 21st Century Act. The
Frank R. Lautenberg Chemical Safety for the 21st Century Act amended the Toxic Substances
Control Act (TSCA), the Nation's primary chemicals management law, on June 22, 2016. The
new law includes statutory requirements and deadlines for actions related to conducting risk
evaluations of existing chemicals.
Under TSCA § 6(b), the Environmental Protection Agency (EPA) must designate chemical
substances as high-priority substances for risk evaluation or low-priority substances for which
risk evaluations are not warranted at the time, and upon designating a chemical substance as a
high-priority substance, initiate a risk evaluation on the substance. TSCA § 6(b)(4) directs EPA
risk evaluations for existing chemicals, 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."
TSCA § 6(b)(4)(D) and implementing regulations require that EPA publish the scope of the risk
evaluation to be conducted, including the hazards, exposures, conditions of use and potentially
exposed or susceptible subpopulations that the Administrator expects to consider, within 6
months after the initiation of a risk evaluation. In addition, a draft scope is to be published
pursuant to 40 CFR 702.41. In December 2019, EPA published a list of 20 chemical substances
that have been designated high priority substances for risk evaluations (Docket ID: EPA-HQ-
OPPT-2018-0444), as required by TSCA § 6(b)(2)(B), which initiated the risk evaluation process
for those chemical substances. o-Dichlorobenzene is one of the chemicals designated as a high
priority substance for risk evaluation.
2 SCOPE OF THE EVALUATION
2.1 Reasonably Available Information
EPA conducted a comprehensive search for reasonably available information1 to support the
development of this draft scope document for o-dichlorobenzene. EPA leveraged the data and
information sources already collected in the documents supporting the chemical substance's
high-priority substance designation. In addition, EPA searched for additional data and
information physical and chemical properties, environmental fate, engineering, exposure,
environmental and human health hazards that could be obtained from the following general
categories of sources:
1. Databases containing publicly available, peer-reviewed literature;
1 Reasonably available information means information that EPA possesses or can reasonably generate, obtain, and
synthesize for use in risk evaluations, considering the deadlines specified in TSCA section 6(b)(4)(G) for
completing such evaluation. Information that meets the terms of the preceding sentence is reasonably available
information whether or not the information is confidential business information, that is protected from public
disclosure under TSCA section 14 (40 CFR 702.33).

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2.	Gray literature, which is defined as the broad category of data/information sources not
found in standard, peer-reviewed literature databases.
3.	Data and information submitted under TSCA sections 4, 5, 8(e), and 8(d), as well as "for
your information" (FYI) submissions
Following the comprehensive search, EPA performed a title and abstract screening to identify
information potentially relevant for the risk evaluation process. This step also classified the
references into useful categories or tags to facilitate the sorting of information through the
systematic review process. The search and screening process was conducted based on EPA's
general expectations for the planning, execution and assessment activities outlined in the
Application of Systematic Review in TSCA Risk Evaluations document (U.S. EPA, 2018a). EPA
plans to publish supplemental documentation on the systematic review methods supporting the o-
dichlorobenzene risk evaluation to explain the literature and screening process presented in this
document in the form of literature inventory trees. Please note that EPA focuses on the data
collection phase (consisting of data search, data screening, and data extraction) during the
preparation of the TSCA scope document, whereas the data evaluation and integration stages will
occur during the development of the draft risk evaluation and thus are not part of the scoping
activities described in this document.
The subsequent sections summarize the data collection activities completed to date for the
general categories of sources and topic areas (or disciplines) using systematic review methods.
EPA plans to seek public comments on the systematic review methods supporting the risk
evaluation for o-dichlorobenzene upon publication of the supplemental documentation of those
methods.
2.1.1 Search of Gray Literature
EPA surveyed the gray literature2 and identified 116 search results relevant to EPA's risk
assessment needs for o-dichlorobenzene. Appendix A lists the gray literature sources that yielded
116 discrete data or information sources relevant to o-dichlorobenzene. EPA further categorized
the data and information into the various topic areas (or disciplines) supporting the risk
evaluation (e.g., physical chemistry, environmental fate, ecological hazard, human health hazard,
exposure, engineering) and the breakdown is shown in Figure 2-1. EPA is currently identifying
additional reasonably available information (e.g., public comments), and the reported numbers in
Figure 2-1 may change.
2 Gray literature is defined as the broad category of data/information sources not found in standard, peer-reviewed
literature databases (e.g., PubMed and Web of Science). Gray literature includes data/information sources such as
white papers, conference proceedings, technical reports, reference books, dissertations, information on various
stakeholder websites and other databases.
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Gray Literature Tags by Discipline
Physical.Chemical
Human.Health.Hazard
Environmental.Hazard
Engineering
0	25	50	75	100
Percent Tagged (%)
Figure 2-1. Gray Literature Tags by Discipline for o-Dichlorobenzene
The percentages across disciplines do not add up to 100%, as each source may provide data or information for
various topic areas (or disciplines).
2.1.2 Search of Literature from Publicly Available Databases (Peer-reviewed
Literature)
EPA is currently conducting a systematic review of the reasonably available literature. This
includes performing a comprehensive search of the reasonably available peer review literature on
physical-chemical properties, environmental fate and transport, engineering (environmental
release and occupational exposure), exposure (environmental, general population and consumer)
and environmental and human health hazards of o-dichlorobenzene. Eligibility criteria were
applied in the form of PECO (population, exposure, comparator, outcome) statements. Included
references met the PECO criteria, whereas excluded references did not meet the criteria (i.e., not
relevant), and supplemental material was considered as potentially relevant. EPA plans to
evaluate the reasonably available information identified for each discipline during the
development of the risk evaluation. The literature inventory trees depicting the number of
references that were captured and those that were included, excluded, or tagged as supplemental
material during the screening process for each discipline area are shown in Figure 2-2 through
Figure 2-6. "TIAB" in these figures refer to "title and abstract" screening. Note that in some
figures the sum of the numbers for the various sub-categories may be larger than the broader
category because some studies may be included under multiple sub-categories. In other cases, the
sum of the various sub-categories may be smaller than the main category because some studies
may not be depicted in the sub-categories if their relevance to the risk evaluation was unclear.
15

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Boiling Point
Water Solublity
log KOW
Henry's Law Constant
Vapor Pressure
Vapor Density
Density
15
24
Viscosity
Retrieved for Full-text
Review
Included for Data
Extraction and Data
Evaluation
Dielectric Constant
447
Refractive Index
Total for TIAB:
P-Chem
423
Supplemental Information
Exclusion
Exclusion
Figure 2-2. Peer-Reviewed Literature- Physical-Chemical Properties Search Results for
o-Dichlorobenzene
16

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©
Bioconcentration, Biomagnification, etc.
TSCA Fate o-DCB (2020)
Included
©( 1281 J
w
©
Supplemental
©
Biodegradation
©
Hydrolysis
12
Photolysis
©
Sorption
36
Volatilization
Wastewater Treatment
©
Figure 2-3. Peer-reviewed Literature - Fate Search Results for o-Dichlorobenzene
Click here for interactive Health Assessment Workplace Collaborative (HAWC) diagram
17

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Genera] Facility Estimate
Environmental Releases
127
Occupational Exposure
Total for TIAB:
Engineering
101
3,0S~
Supplemental
Figure 2-4. Peer-reviewed Literature - Engineering Search Results for o-Dichlorobenzene
18

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surface water (2)
soil (1)
ground water (39)
Supplemental (65)
drinking water (22)
biosolids/ sludge (3)
ambient air (2)
terrestrial species (8)
surface water (99)
Unique HERO IDs (928)
Exclude (348)
sediment (41)
no evidence (not PECO-relevant) (2)
indoor air (111)
ground water (30)
Include (515)
Relevant (420)
evidence unclear (PECO relevancy unclear) (2)
epidemiological/ human biomonitoring study (70)
drinking water (14)
dietary (9)
consumer uses and/or product (15)
biosolids/ sludge (14)
aquatic species (17)
ambient air (120)
Unclear (95)
evidence unclear (PECO relevancy unclear) (95)
Figure 2-5. Peer-reviewed Exposure Search Results for o-Dichlorobenzene
19

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566
Retrieved for Full-text
Review
3583
Total for TIAB:
Hazard
>{ 3017
Exclusion
Figure 2-6. Peer-reviewed Hazard Search Results for o-Dichlorobenzene
2.1.3 Search of TSCA Submissions
Table 2-1 presents the results of screening the titles of data sources and reports submitted to EPA
under various sections of TSCA. EPA screened a total of 129 submissions using
inclusion/exclusion criteria specific to individual disciplines (see Table 2-1 for the list of
disciplines). The details about the criteria are not part of this document but will be provided in a
supplemental document that EPA anticipates releasing prior to the finalization of the scope
document. EPA identified 89 submissions that met the inclusion criteria in these statements and
identified 28 submissions with supplemental data. EPA excluded 12 submissions because the
reports were identified as one of the following:
•	Published report that would be identified via other peer or gray literature searches
•	Summary of other reports
•	Preliminary report of a final available submitted report
•	Duplicate of another report
•	Submission on a different chemical
•	List of references with no original data
EPA plans to conduct additional deduplication at later stages of the systematic review process
(e.g., full text screening), when more information regarding the reports is available.
20

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Table 2-1. Results of Title Screening of Submissions to EPA under Various Sections of TSCAa
Discipline
Included
Supplemental h
Physicochemical Properties
1
0
Environmental Fate and
10
0
Transport


Environmental and General
46
1
Population Exposure


Occupational
Exposure/Release Information
12
0
Environmental Hazard
5
2
Human Health Hazard
30
25
a Individual submissions may be relevant to multiple disciplines.
b Included submissions may contain supplemental data for other disciplines, which will be identified at full-text review.
2.2 Conditions of Use
As described in the Proposed Designation of o-Dichlorobenzene (CASRN 95-50-1) as aHmh-
Priority Substance for Risk Evaluation (U.S. EPA, 2019a), EPA assembled information from the
CDR and TRI programs to determine conditions of use3 or significant changes in conditions of
use of the chemical substance. EPA also consulted a variety of other sources to identify uses of
o-dichlorobenzene, including: published literature, company websites, and government and
commercial trade databases and publications. To identify formulated products containing o-
dichlorobenzene, EPA searched for safety data sheets (SDS) using internet searches, EPA
Chemical and Product Categories (CPCat) data, and other resources in which SDSs could be
found. SDSs were cross-checked with company websites to make sure that each product SDS
was current. In addition, EPA incorporated communications with companies, industry groups,
environmental organizations, and public comments to supplement the use information.
EPA identified and described the categories and subcategories of conditions of use that will be
included in the scope of the risk evaluation (Section 2.2.1; Table 2-2). The conditions of use that
EPA plans to include in the scope are those reflected in the life cycle diagrams and conceptual
models.
After gathering reasonably available information related to the manufacture, processing,
distribution in commerce, use and disposal of o-dichlorobenzene, EPA identified those
categories or subcategories of use activities for o-dichlorobenzene the Agency determined not to
be conditions of use or will otherwise be excluded during scoping. These categories and
subcategories are described in Section 2.2.2.
3 Conditions of use means 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.
21

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2.2.1 Categories and Subcategories of Conditions of Use Included in the
Scope of the Risk Evaluation
Table 2-2 lists the conditions of use that are included in the scope of the risk evaluation.
Table 2-2. Categories and Subcategories of Conditions of Use Included in the Scope of the
Risk Evaluation
l.il'e-Cvcle Stage
Category
S ii beat ego rv
Reference
Manufacturing
Domestic
manufacture/Import
CBI
U.S. EPA, 2019b
Import
Import
U.S. EPA, 2019b
Processing
Processing as a
reactant
In All other chemical product
and preparation manufacturing
U.S. EPA, 2019b
Processing -
incorporation into
formulation, mixture
or reaction product
Intermediates in All other basic
organic chemical
manufacturing
U.S. EPA, 2019b
Solvents (which become part
of product formulation or
mixture) in Plastic material and
resin manufacturing
U.S. EPA, 2019b;
EP A-HO-OPPT -
20 i 8-0444-00!3

Pigments in: Printing ink
manufacturing; Paint and
coating manufacturing;
Synthetic dye and pigment
manufacturing
U.S. EPA, 2019b
Distribution in
commerce
Distribution in
commerce
Distribution in commerce

Commercial use
Ink, toner, and
colorant products
Ink and toners
U.S. EPA, 2019b;
EP A-HO-OPPT -
2018-0444-0004
Paints and coatings
Coatings and paints, thinners,
paint removers
U.S. EPA, 2019b;
EP A-HO-OPPT -
2018-0444-0004
Lubricants and
greases
Lubricants and greases,
degreasers
EPA-HO-OPPT-
2018-0444-0004;
EP A-HO-OPPT-
2018-0444-0013;
EPA-HO-OPPT-
2;
Marvel Oil
Company (2017)
22

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Air care products
Continuous action air
fresheners (including
toilet/urinal
deodorizers/fresheners)
DeLima Associates
(2014)
Other use
e.g., Laboratory chemicals;
Sheep-branding fluid; Cleaning
and furniture care products
EP A-HO-OPPT -
;
Heiniger (2016)
Consumer use
Lubricants and
greases
Lubricants and greases,
degreasers
EP A-HO-OPPT -
20IN 04 1 i OOl.'s
EP A-HO-OPPT-
2;
Marvel Oil
Company (2017)
Air care products
Continuous action air
fresheners (including
toilet/urinal
deodorizers/fresheners)
DeLima Associates
(2014)
Other use
e.g., Thinners (Products for
cleaning brushes and tools
used with overglazes);
Ceramics glaze; Sheep-
branding fluid; Cleaning and
furniture care products
EP A-HO-OPPT -
jms oi 11 i;,
Duncan Enterprises
(2014); Duncan
Enterprises (2015);
Heiniger (2016)
Disposal
Disposal
Disposal

•	Life Cycle Stage Use Definitions (40 CFR § 711.3)
-	"Industrial use" means use at a site at which one or more chemicals or mixtures are manufactured
(including imported) or processed.
-	"Commercial use" means the use of a chemical or a mixture containing a chemical (including as part of an
article) in a commercial enterprise providing saleable goods or services.
-	"Consumer use" means the use of a chemical or a 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.
•	Although EPA has identified both industrial and commercial uses here for purposes of distinguishing scenarios in
this document, the Agency interprets the authority over "any manner or method of commercial use" under TSCA
section 6(a)(5) to reach both.
•	These categories of conditions of use appear in the Life Cycle Diagram, reflect CDR codes, and broadly
represent conditions of use of o-Dichlorobenzene in industrial and/or commercial settings
•	These subcategories reflect more specific uses of o-Dichlorobenzene.
•	At this time, "CBI" indicates that a data element has been claimed CBI by the information submitter; it does not
reflect the result of an EPA substantiation review.
2.2.2 Activities Excluded from the Scope of the Risk Evaluation
As explained in the final rule for Procedures for Chemical Risk Evaluation Under the Amended
Toxic Substances Control Act, TSCA section 6(b)(4)(D) requires EPA to identify the hazards,
23

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exposures, conditions of use, and the potentially exposed or susceptible subpopulations the
Administrator expects to consider in a risk evaluation, suggesting that EPA may exclude certain
activities that it determines to be conditions of use on a case-by-case basis. (82 FR 33736, 33729;
July 20, 2017). TSCA section 3(4) also grants EPA the authority to determine what constitutes a
condition of use for a particular chemical substance. EPA does not plan to include in this scope
or in the risk evaluation the activities described below that the Agency has concluded do not
constitute conditions of use.
Public comments submitted to EPA in the docket indicate the use of o-dichlorobenzene in
pesticides (EPA-HQ-OPPT-2018-0444-0013) but these activities are not "conditions of use"
(defined in TSCA § 3(4)) as circumstances associated with "a chemical substance," as defined in
TSCA § 3(2). TSCA defines "chemical substance" to exclude pesticides, which are covered
under EPA's Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. § 136 et
seq. (1996). Additionally, the last pesticidal products containing o-dichlorobenzene were
cancelled in 1992. Therefore, the use of o-dichlorobenzene in pesticides is outside the scope of
the definition of chemical substance4 as regulated by TSCA and EPA does not plan to consider
those activities in the risk evaluation.
2.2.3	Production Volume
As reported to EPA during the 2016 CDR reporting period and described here as a range to
protect production volumes that were claimed as confidential business information (CBI), total
production volume of o-dichlorobenzene in 2015 was between 100,000 and 500,000 pounds
(Figure 2-1) (U.S. EPA, 2017). EPA also uses pre-2015 CDR production volume information, as
detailed in the Proposed Designation of o-Dichlorobenzene fCASRN 95-50-1) as a High-Priority
Substance for Risk Evaluation (U.S. EPA, 2019a) and will include future production volume
information as it becomes available to support the exposure assessment.
2.2.4	Overview of Conditions of Use and Lifecycle Diagram
The life cycle diagram provided in Figure 2-7 depicts the conditions of use that are considered
within the scope of risk evaluation for the various life cycle stages. This section provides a brief
overview of the industrial, commercial and consumer use categories included in the life cycle
diagram. The activities that EPA determined are out of scope are not included in the life cycle
diagram. 2.8Appendix E contains additional descriptions (e.g., process descriptions, worker
activities, process flow diagrams) for each manufacture, processing, distribution in commerce,
use and disposal category.
4 Chemical substance means any organic or inorganic substance of a particular molecular identity, including any
combination of such substances occurring in whole or in part as a result of a chemical reaction or occurring in
nature, and any element or uncombined radical. Chemical substance does not include (1) any mixture; (2) any
pesticide (as defined in the Federal Insecticide, Fungicide, and Rodenticide Act) when manufactured, processed, or
distributed in commerce for use as a pesticide; (3) tobacco or any tobacco product; (4) any source material, special
nuclear material, or byproduct material (as such terms are defined in the Atomic Energy Act of 1954 and regulations
issued under such Act); (5) any article the sale of which is subject to the tax imposed by section 4181 of the Internal
Revenue Code of 1954 (determined without regard to any exemptions from such tax provided by section 4182 or
4221 or any other provision of such Code), and; (6) any food, food additive, drug, cosmetic, or device (as such terms
are defined in section 201 of the Federal Food, Drug, and Cosmetic Act) when manufactured, processed, or
distributed in commerce for use as a food, food additive, drug, cosmetic, or device.
24

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The information in the life cycle diagram is grouped according to the CDR processing codes and
use categories (including functional use codes for industrial uses and product categories for
industrial, commercial and consumer uses).
25

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MFG/IMPORT
PROCESSING
INDUSTRIAL, COMMERCIAL, CONSUMER USES RELEASES and WASTE DISPOSAL
Manufacture
(Includes Import)
100K - 500K lbs/yr
Processing as a Reactant
(e.g. in all other chemical product and
preparation manufacturing)
Incorporation into formulation,
mixture or reaction product
(e.g., intermediates in all other
basic organic chemical
manufacturing; Solvents (which
become part of product
formulation or mixture) in
plastic material and resin
manufacturing; Pigments in:
printing ink manufacturing; Paint
and coating manufacturing;
Synthetic dye and pigment
Recycling
Other Uses
e.g., laboratory chemicals;
ceramics glaze; sheep-branding
fluid; furniture care products
Ink, Toner, and Colorant
1
Products
e.g., ink and toners
Paints and Coatings
e.g., coating and paints;
thinners; paint removers
u
Lubricants and greases
e.g., lubricants and greases,
degreasers
1,2
Air care products
e.g., continuous action air
fresheners (including
toilet/urinal
deodorizers/fresheners)
Disposal
See Conceptual Model for
Environmental Releases
and Wastes
Manufacture (Including Import)
Processing
Uses:
1.	Industrial and/or commercial
2.	Consumer
Figure 2-7. o-Dichlorobenzene Life Cycle Diagram
Volume is not depicted in the life cycle diagram for processing and industrial, commercial, and consumer uses as specific production volume is claimed confidential business information
(CBI) or withheld pursuant to TSCA Section § 14.
26

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2.3 Exposures
For TSCA exposure assessments, EPA plans to analyze exposures and releases to the
environment resulting from the conditions of use within the scope of the risk evaluation of o-
dichlorobenzene. 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 environmental
receptors. EPA plans to consider, where relevant, the duration, intensity (concentration),
frequency and number of exposures in characterizing exposures to o-dichlorobenzene.
2.3.1	Physical and Chemical Properties
Physical and chemical properties are essential for a thorough understanding or prediction of
environmental fate (i.e., transport and transformation) and the eventual environmental
concentrations. They can also inform the hazard assessment. EPA plans to use the physical and
chemical properties described in Table 7 of the Proposed Designation of o-DicMorobenzene
fCASRN 95-50-1) as a High-Priority Substance for Risk Evaluation (U.S. EPA, 2019a) to
support the development of the risk evaluation for o-dichlorobenzene. The values for the
physical and chemical properties (Appendix B) may be updated as EPA collects additional
information through systematic review methods.
2.3.2	Environmental Fate and Transport
Understanding of environmental fate and transport processes assists in the determination
of the specific exposure pathways and potential human and environmental receptors that need to
be assessed in the risk evaluation for o-dichlorobenzene. EPA plans to use the environmental fate
characteristics described in Appendix C of the Proposed Designation of o-Dichlorobenzene
fCASRN 95- is a High-Priority Substance for Risk Evaluation (U.S. EPA, 2019a) to
support the development of the risk evaluation for o-dichlorobenzene. The values for the
environmental fate properties (Appendix C) may be updated as EPA collects additional
information through systematic review methods.
2.3.3	Release to the Environment
Releases to the environment from conditions of use (e.g., manufacturing, industrial, and
commercial processes, commercial or consumer uses) are a 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.
A source of information that EPA plans to consider in evaluating exposure are data reported to
the Toxics Release Inventory (TRI) program. EPA's TRI database contains information on
chemical waste management activities that are disclosed by industrial and federal facilities,
including quantities released into the environment (i.e., to air, water, and disposed of to land),
treated, burned for energy, recycled, or transferred off-site to other facilities for these purposes.
Under the Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA,
o-dichlorobenzene is a TRI-reportable substance, under the name 1,2-dichlorobenzene, effective
January 01, 1987 (40 CFR 372.65). For TRI reporting5, facilities in covered sectors in the United
5 For TRI reporting criteria see https://www.epa.gov/toxics-release-inventorv-tri-program/basics-tri-reporting
27

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States are required to disclose releases and other waste management activity quantities of o-
dichlorobenzene under the CASRN 95-50-1 if they manufacture (including import) or process
more than 25,000 pounds or otherwise use more than 10,000 pounds of the chemical in a given
year by July 1 of the following year.
Table 2-3 provides production-related waste management data for o-dichlorobenzene reported by
facilities to the TRI program for reporting year 2018.6 As shown in the table, 17 facilities
reported in total over 55.3 million pounds of o-dichlorobenzene waste for 2018. Nearly all (97%)
of the o-dichlorobenzene managed as waste during 2018 was managed on site by recycling.
Waste treatment quantities (nearly 1.6 million pounds) accounted for 2.8% of the total.
Contributions from quantities burned for energy recovery or released to the environment were
very small, amounting to only 0.5% and 0.1%, respectively, of the total quantity of o-
dichlorobenzene managed as waste during 2018. Overall, 99.2% of the o-dichlorobenzene
production-related waste was managed as such on site.
Table 2-3. Summary of o-Dichlorobenzene TRI Production-Related Waste Managed in
2018
Year
Number of
Kacilities
(lbs)
Recycled
(lbs)
Recovered
lor
Knergv
(lbs)'
Treated
(lbs)
Released111"
(lbs)
Total
Production
Related
Waste
(lbs)
2018
17
53,448,206
272,008
1,560,880
62,159
55,343,252
Data source: 2018 TRI Data (U.S. EPA, 2019c)
3 Terminology used in these columns may not match the more detailed data element names used in the TRI public data and analysis access points.
b Does not include releases due to one-time event not associated with production such as remedial actions or earthquakes.
c Counts all releases including release quantities transferred and release quantities disposed of by a receiving facility reporting to TRI.
Table 2-4 provides a summary of o-dichlorobenzene released to the environment during 2018 as
reported to TRI.2 Land disposal and releases to air accounted for nearly all releases to the
environment, with extremely minor contributions from discharges to water and other releases.
Roughly 55%) of total releases were in the form of land disposal, with slightly more than half in
RCRA Subtitle C landfills, and slightly less than half in Class I underground injection wells, o-
Dichlorobenzene releases to air accounted for nearly all remaining environmental releases.
Roughly 60%) of these air releases originated from point sources with fugitive air releases
accounting for the remainder. Overall, more than 99.9% of o-dichlorobenzene releases during
2018 occurred on site, and only about three pounds of o-dichlorobenzene waste were sent off site
for disposal.
6 Reporting year 2018 is the most recent TRI data available. Data presented in Table2-3 were queried using TRI
Explorer and uses the 2018 National Analysis data set (released to the public in November 2019). This dataset
includes revisions for the years 1988 to 2018 processed by EPA.
28

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Table 2-4. Summary of Releases of o-Dichlorobenzene to the Environment During 2018
Year
Nil in her
ol'
l-'acililies
Air Releases
\\ aler
Releases
l.aiul Disposal
Oilier
Releases
.1
(lbs)
lolal
Releases 1,1
(lbs)
Stack Air
Releases
(lbs)
Fugitive
Air
Releases
(lbs)
Class I
Under-
ground
Injection
(lbs)
RCRA
Subtitle C
Landfills
(lbs)
All other
Land
Disposala
(lbs)
2018
17
16,672
11,380
7
15,700
18,400
0
0.101
62,159
28,052
34,100
Data source: 2018 TRI Data (U.S. EPA, 2019c)
' Terminology used in these columns may not match the more detailed data element names used in the TRI public data and analysis access points.
b These release quantities do include releases due to one-time events not associated with production such as remedial actions or earthquakes.
c Counts release quantities once at final disposition, accounting for transfers to other TRI reporting facilities that ultimately dispose of the chemical waste.
While production-related waste managed shown in Table 2-3 excludes any quantities reported as
catastrophic or one-time releases (TRI section 8 data), release quantities shown in Table 2-4
include both production-related and non-production-related quantities. For o-dichlorobenzene the
total release quantities shown in each table are the same, but for other TRI chemicals total
release quantities between the two tables may differ slightly and may further reflect differences
in TRI calculation methods for reported release range estimates (U.S. EPA, 2019d).
EPA plans to review these data in conducting the exposure assessment component of the risk
evaluation for o-dichlorobenzene.
2.3.4	Environmental Exposures
The manufacturing, processing, distribution, use and disposal of o-dichlorobenzene can result in
releases to the environment and exposure to aquatic and terrestrial receptors (biota).
Environmental exposures to biota are informed by releases into the environment, overall
persistence, degradation, and bioaccumulation within the environment, and partitioning across
different media. Concentrations of chemical substances in biota provide evidence of exposure.
EPA plans to review reasonably available information on environmental exposure in biota to
inform development of the environmental exposure assessment for o-dichlorobenzene.
2.3.5	Occupational Exposures
EPA plans to evaluate worker activities where there is a potential for exposure under the various
conditions of use (manufacturing, processing and industrial/commercial uses) described in
Section 2.2. In addition, EPA plans to evaluate exposure to occupational non-users (ONUs), i.e.,
workers who do not directly handle the chemical but perform work in an area where the chemical
is present. EPA also expects to consider the effect(s) that engineering controls and/or personal
protective equipment have on occupational exposure levels as part of the draft risk evaluation.
Worker activities associated with the conditions of use within the scope of the risk evaluation for
o-dichlorobenzene that will be analyzed include, but are not limited to:
•	Unloading and transferring o-dichlorobenzene to and from storage containers and process
vessels;
•	Handling, transporting and disposing of waste containing o-dichlorobenzene;
29

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•	Cleaning and maintaining equipment;
•	Sampling chemicals, formulations, or products containing o-dichlorobenzene for quality
control;
•	Repackaging chemicals, formulations, or products containing o-dichlorobenzene;
o-Dichlorobenzene is a liquid with vapor pressure of 1.36 mmHg at room temperature. Based on
the chemical's volatility, EPA plans to analyze inhalation exposure to vapor for workers and
ONUs. EPA also plans to evaluate inhalation exposure to mists for workers and ONUs where
products containing o-dichlorobenzene may be spray-applied. EPA plans to evaluate dermal
exposures for workers, who are expected to have skin contact with o-dichlorobenzene.
Occupational non-users do not directly handle o-dichlorobenzene; therefore, skin contact with o-
dichlorobenzene is not expected for occupational non-users.
In addition, for certain COUs, o-dichlorobenzene may be present as a component of solid
products. For these COUs, EPA plans to consider inhalation exposure to dust/particulates (e.g.,
particulate generated during handling of plastic resins, finishing operations associated with the
manufacture and finishing of plastics and plastic articles and incorporation of plastics and other
article components into finished products) for workers and ONUs.
EPA generally does not evaluate occupational exposures through the oral route because oral
exposure is typically incidental in nature. Workers may inadvertently transfer chemicals from
their hands to their mouths, ingest inhaled particles that deposit in the upper respiratory tract or
consume contaminated food, the frequency and significance of this exposure route are dependent
on several factors including the p-chem properties of the substance during expected worker
activities, workers' awareness of the chemical hazards, the visibility of the chemicals on the
hands while working, workplace practices, and personal hygiene that is difficult to predict
(Cherrie et al., 2006). However, EPA will consider oral exposure on a case-by-case basis for
certain COUs and worker activities where there is information and data on incidental ingestion of
inhaled dust. EPA will consider ingestion of inhaled dust as an inhalation exposure for o-
dichlorobenzene.
The United States has several regulatory and non-regulatory exposure limits for o-
dichlorobenzene: the Occupational Safety and Health Administration (OSHA) permissible
exposure limit (PEL) (29 CFR 1910.1000) and the National Institute for Occupational Safety and
Health (NIOSH) Recommended Exposure Limit (REL) (NIOSH, 2019) are both equal to 50
parts per million (ppm) or 300 milligrams (mg)/cubic meter (m3) as a ceiling limit.
2.3.6 Consumer Exposures
According to reports of the 2016 CDR, lubricants and greases, air care products, as well as other
uses, such as, thinners, ceramics glaze, sheep-branding fluid, and cleaning and furniture care
products, were identified as consumer products containing o-dichlorobenzene. Consumers using
or disposing of o-dichlorobenzene-based lubricants and greases, air care products, and other
products may be exposed to o-dichlorobenzene through direct solid and liquid contact which
may lead to dermal exposure, through vapor emissions, which may lead to inhalation exposure,
or through mist generation which may lead to inhalation and dermal exposure (see Appendix D).
Bystanders present during the consumer use of lubricants and greases, air care products, and
30

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other products or disposal of o-dichlorobenzene may also be exposed to vapor emissions and
mist generation which may lead to inhalation and dermal exposure. Based on these potential
sources and pathways of exposure, EPA plans to analyze dermal and inhalation routes of
exposure to consumers that may result from the conditions of use of o-dichlorobenzene.
There were no reports to CDR of any use of o-dichlorobenzene in children's products.
2.3.7 General Population Exposures
EPA plans to review reasonably available environmental monitoring data for o-dichlorobenzene.
Outdoor air levels have been measured and range from 0.01 to 0.1 ppb for o-dichlorobenzene
(ATSDR 2006). The primary route of exposure for the general population is inhalation. Average
intake values for the general population were estimated to be 1.8 |ig/day, on the basis of ambient
outdoor samples from seven large U.S. cities (ATSDR 2006). Several groups within the general
population have potentially higher exposures (higher than background levels) to o-
dichlorobenzene. These populations include individuals living near sites where o-
dichlorobenzene is produced or used in manufacturing and disposal sites. Individuals living in
proximity to hazardous waste sites may also be exposed to o-dichlorobenzene by contaminated
groundwater. If residential wells are the primary source of drinking water, this may pose a risk to
human health by consumption of contaminated water and by increased inhalation of and dermal
contact during showering and bathing (ATSDR 2.006). Additionally, the National Fish Tissue
Study states potential exposure for the general population is likely to this chemical in fish tissue
from lakes and reservoirs of the continental United States (	)09).
2.4 Hazards (Effects)
2.4.1	Environmental Hazards
As described in the Proposed Designation of o-Dichlorobenzene (CASRN 95-50-1) as a High-
Priority Substance for Risk Evaluation (U.S. EPA, 2019a), EPA considered reasonably available
information from peer-reviewed assessments and databases to identify potential environmental
hazards for o-dichlorobenzene. EPA considers all the potential environmental hazards for o-
dichlorobenzene identified during prioritization to be relevant for the risk evaluation and thus
they remain within the scope of the evaluation. EPA is in the process of identifying additional
reasonably available information through systematic review methods and public comments,
which may update the list of potential environmental hazards associated with o-dichlorobenzene.
If necessary, EPA plans to update the list of potential hazards in the final scope document for o-
dichlorobenzene. Based on information identified during prioritization, environmental hazard
effects were identified for aquatic and terrestrial organisms.
2.4.2	Human Health Hazards
As described in the Proposed Designation of o-Dichlorobenzene (CASRN 95-50-1) as a High-
Priority Substance for Risk Evaluation (U.S. EPA, 2019a), EPA considered reasonably available
information from peer-reviewed assessments and databases to identify potential human health
hazards for o-dichlorobenzene. EPA plans to evaluate all of the potential human health hazards
for o-dichlorobenzene identified during prioritization. The health effect categories screened for
during prioritization included acute toxicity, irritation/corrosion, dermal sensitization, respiratory
sensitization, genetic toxicity, repeated dose toxicity, reproductive toxicity, developmental
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toxicity, immunotoxicity, neurotoxicity, carcinogenicity, epidemiological or biomonitoring
studies and ADME[1]. The broad health effect categories include reproductive and,
developmental, nervous system, and irritation effects. Studies were identified reporting
information on genotoxicity, carcinogenicity and ADME. EPA is in the process of identifying
additional reasonably available information through systematic review methods and public input,
which may update the list of potential human health hazards under the scope of the risk
evaluation. EPA plans to update the list of potential hazards in the final scope document of the o-
dichlorobenzene risk evaluation.7.
2.5	Potentially Exposed or Susceptible Subpopulations
TSCA§ 6(b)(4) requires EPA to determine whether a chemical substance presents an
unreasonable risk to "a potentially exposed or susceptible subpopulation identified as relevant to
the risk evaluation." TSCA §3(12) states that "the term 'potentially exposed or susceptible
subpopulation' means a group of individuals within the general population identified by the
Administrator who, due to either greater susceptibility or greater exposure, may be at greater risk
than the general population of adverse health effects from exposure to a chemical substance or
mixture, such as infants, children, pregnant women, workers, or the elderly." General population
is "the total of individuals inhabiting an area or making up a whole group" and refers here to the
U.S. general population (U.S. EPA. 2011).
During the Prioritization process, EPA identified the following potentially exposed or susceptible
subpopulations based on CDR information and studies reporting developmental and reproductive
effects: children, women of reproductive age (e.g., pregnant women per TSCA statute), workers
and consumers (U.S. EPA, 2019b). EPA plans to evaluate these potentially exposed or
susceptible subpopulations in the risk evaluation.
In developing exposure scenarios, EPA plans to analyze available data to ascertain whether some
human receptor groups may be exposed via exposure pathways that may be distinct to a
particular subpopulation or life stage (e.g., children's crawling, mouthing or hand-to-mouth
behaviors) and whether some human receptor groups may have higher exposure via identified
pathways of exposure due to unique characteristics (e.g., activities, duration or location of
exposure) when compared with the general population (	36). Likewise, EPA plans
to evaluate available human health hazard information to ascertain whether some human receptor
groups may have greater susceptibility than the general population to the chemical's hazard(s).
2.6	Conceptual Models
In this section, EPA presents the conceptual models describing the identified exposures
(pathways and routes), receptors and hazards associated with the conditions of use of o-
dichlorobenzene. Pathways and routes of exposure associated with workers and ONU's are
described in Section 2.6.1, and pathways and routes of exposure associated with consumers are
described in Section 2.6.2. Pathways and routes of exposure associated with environmental
[1] ADME= absorption, distribution, metabolism, and excretion
7 Refer to table 10 of the Proposed Designation ofp-Dichlorobenzene fCASRN 106-46-7) as a High-Priority
Substance for Risk Evaluation
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releases and wastes, including those pathways that may be addressed pursuant to other Federal
laws are discussed and depicted the conceptual model shown in Section 2.6.3. Pathways and
routes of exposure associated with environmental releases and wastes, excluding those pathways
that may be addressed pursuant to other Federal laws are presented in the conceptual model
shown in Section 2.6.4.
2.6.1 Conceptual Model for Industrial and Commercial Activities and Uses:
Potential Exposures and Hazards
Figure 2-8 illustrates the conceptual model for the pathways of exposure from industrial and
commercial activities and uses of o-dichlorobenzene that EPA plans to include in the risk
evaluation. There is potential for exposures to workers and/or ONU's via inhalation routes and
exposures to workers via dermal routes. It is expected that inhalation exposure to vapors is the
most likely exposure route. In addition, workers at waste management facilities may be exposed
via inhalation or dermal routes via wastewater treatment, incineration or other disposal methods.
EPA plans to evaluate activities resulting in exposures associated with distribution in commerce
(e.g., loading, unloading) throughout the various lifecycle stages and conditions of use (e.g.,
manufacturing, processing, industrial use, commercial use, and disposal) rather than a single
distribution scenario. EPA anticipates inhalation and/or oral exposure for workers and
occupational non-users, and dermal exposure only for workers. In EPA's 1981 risk assessment of
dichlorobenzenes (U.S. EPA, 1981), inhalation exposures to vapor and mist were assessed as the
most likely exposure route; however, there is also potential dermal exposure for some conditions
of use, such as use in paints and coatings.
For each condition of use identified in Table 2-2, an initial determination was made as to
whether each unique combination of exposure pathway, route, and receptor will be analyzed in
the risk evaluation. The results of that analysis along with the supporting rationale are presented
in Appendix F.
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INDUSTRIAL AND
COMMERCIAL ACTIVITIES EXPOSURE PATHWAY EXPOSURE ROUTE	RECEPTORS	HAZARDS
USES
Manufacturing;
including import
Hazards
potentially
associated with
acme and/or
chronic exposares
Processing
-As i reactant
-Incorporated into
formulation, mixture,
or reaction product
Ink, Toner, and
Colorant Products
Paints and Coatings
Lubricants and
Greases
Air Care Products
.	fria&ii:	rr uic-axl anu	rruwj
r (See Environmental Release Conceptual Models)
Figure 2-8. o-Dichlorobenzene Conceptual Model for Industrial and Commercial Activities and Uses: Worker and Occupational Non-User
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 o-dichlorobenzene.
34

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2,6.2 Conceptual Model for Consumer Activities and Uses
The conceptual model in Figure 2-9 presents the exposure pathways, exposure routes and
hazards to human receptors from consumer activities and uses of o-dichlorobenzene. EPA
expects inhalation to be the primary route of exposure and plans to analyze inhalation exposures
to o-dichlorobenzene vapor for consumers and bystanders. There is potential for dermal
exposures to o-dichlorobenzene via direct contact with liquid or solid and via mists generated
during consumer uses, and inhalation exposures to o-dichlorobenzene via vapor and mists
generated from use of consumer products. Bystanders are not expected to have direct dermal
contact to o-dichlorobenzene but may be exposed dermally to mist and dust generation. In
addition, oral exposures to o-dichlorobenzene are expected to be negligible and, as a result, EPA
does not expect to evaluate this route of exposure for consumers nor bystanders. The supporting
rationale for consumer pathways considered for o-dichlorobenzene are included in 2.8Appendix
G.
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CONSUMER ACTIVITIES &
USES
EXPOSURE
PATHWAY
EXPOSURE
ROUTE
RECEPTORS
HAZARDS
Lubricants aid Greases
Air Caie Products
I: f
(e.g., thinners,
- :i :::-Zr
sheep-branding fluid.
furniture care
products)
I : i;.1 ?•-;
Liquid/Solid
.: ::


k ~

Vapor/Mist

M Consumers
p/ Inhalation
(M 5' :tii.der
Hazards Potentially
Associated with
Acute and/or
Chronic Exposures j
Figure 2-9. o-Dichlorobenzene Conceptual Model for Consumer Activities and Uses: Consumer Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes and hazards to human receptors from consumer activities and uses of o-dichlorobenzene.
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2.6.3 Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards (Regulatory Overlay)
In this section, EPA presents the conceptual models describing the identified exposures
(pathways and routes), receptors and hazards associated with the conditions of use of o-
dichlorobenzene within the scope of the risk evaluation. It also discusses those pathways that
may be addressed pursuant to other Federal laws.
In complying with TSCA, EPA plans to efficiently use Agency resources, avoid duplicating
efforts taken pursuant to other Agency programs, maximize scientific and analytical efforts, and
meet the statutory deadline for completing risk evaluations. OPPT is working closely with the
offices within EPA that administer and implement the Clean Air Act (CAA), the Safe Drinking
Water Act (SDWA), the Clean Water Act (CWA) and the Resource Conservation and Recovery
Act (RCRA), to identify how those statutes and any associated regulatory programs address the
presence of o-dichlorobenzene in exposure pathways falling under the jurisdiction of these EPA
statutes.
The conceptual model in Figure 2-10 presents the potential exposure pathways, exposure routes
and hazards to human and environmental receptors from releases and waste streams associated
with industrial, commercial and consumer uses of o-dichlorobenzene. The conceptual model
shows the overlays, labeled and shaded to depict the regulatory programs (e.g., SDWA, CWA,
RCRA) and associated pathways that EPA considered in developing this conceptual model for
the draft scope document. The regulatory programs that cover these environmental release and
waste pathways are further described in Section 2.6.3.1 through Section 2.6.3.3.
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RELEASES AND WASTES FROM	rv„
INDUSTRIAL / COMMERCIAL /	EXPOSURE PATHWAYS	rot tVc	RECEPTORS	HAZARDS
CONSUMER USES
CWA-AWOC
Industrial Pre-
Treatment or
Industrial WWT
SDWA
Water, Sediment
Indirect discharge
Aquatic
Species
Wastewater or
Liquid Wastes
POTW
RCRA-HazList
Underground
injection
Drinking
Water
Biosolids
Hazardous and
Municipal Waste
1 .andfill
Land
Disposal
Hazards Potentially
Associated with
Acute and/or Chronic
Exposures
Dermal
Ground
Water
Soil
Solid Wastes
Hazardous and
Municipal Waste
Incinerators
Liquid Wastes
Inhalation
Fugitive Emissions
Off-site Waste
Transfer
Air
Recycling, Other
Treatment
Emissions to Air
Figure 2-10. o-Dichlorobenzene Conceptual Model for Environmental Releases and Wastes: Environmental and General
Population Exposures and Hazards (Regulatory Overlay)
The conceptual model presents the exposure pathways, exposure routes and hazards to human receptors from releases and wastes from industrial and commercial
uses of o-dichlorobenzene showing the regulatory laws that adequately assess and manage those pathways.
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2.6.3.1	Drinking Water Pathway
EPA has promulgated National Primary Drinking Water Regulations (NPDWRs) under the Safe
Drinking Water Act for o-dichlorobenzene. EPA has set an enforceable Maximum Contaminant
Level (MCL) as close as feasible to a health based, non-enforceable Maximum Contaminant
Level Goal (MCLG). Feasibility refers to both the ability to treat water to meet the MCL and the
ability to monitor water quality at the MCL, SDWA Section 1412(b)(4)(D), and public water
systems are required to monitor for the regulated chemical based on a standardized monitoring
schedule to ensure compliance with the MCL. The MCL for o-dichlorobenzene in water is 0.6
mg/L.
The drinking water exposure pathway for o-dichlorobenzene is currently addressed in the SDWA
regulatory analytical process for public water systems. EPA's Office of Water and Office of
Pollution Prevention and Toxics will continue to work together providing understanding and
analysis of the SDWA regulatory analytical processes and to exchange information related to
toxicity and occurrence data on chemicals undergoing risk evaluation under TSCA.
2.6.3.2	Ambient Water Pathway
EPA develops recommended water quality criteria under section 304(a) of the CWA for
pollutants in surface water that are protective of aquatic life or human health designated uses.
EPA has developed recommended water quality criteria for protection of human health for o-
dichlorobenzene which are available for possible adoption into state water quality standards and
are available for possible use by NPDES permitting authorities in deriving effluent limits to meet
state narrative criteria. EPA's OW and OPPT will continue to work together providing
understanding and analysis of the CWA water quality criteria development process and to
exchange information related to toxicity of chemicals undergoing risk evaluation under TSCA.
EPA may update its CWA section 304(a) water quality criteria for o-dichlorobenzene in the
future under the CWA.
EPA has developed CWA section 304(a) recommended human health criteria for 122 chemicals
and aquatic life criteria for 47 chemicals. A subset of these chemicals is identified as "priority
pollutants" (103 human health and 27 aquatic life), including o-dichlorobenzene. The CWA
requires that states adopt numeric criteria for priority pollutants for which EPA has published
recommended criteria under section 304(a), the discharge or presence of which in the affected
waters could reasonably be expected to interfere with designated uses adopted the state. For
pollutants with recommended human health criteria, EPA regulations require that state criteria
contain sufficient parameters and constituents to protect designated uses. Once states adopt
criteria as water quality standards, the CWA requires that National Pollutant Discharge
Elimination System (NPDES) discharge permits include effluent limits as stringent as necessary
to meet standards CWA section 301(b)(1)(C). This permit issuance process accounts for risk in
accordance with the applicable ambient water exposure pathway (human health or aquatic life as
applicable) for the designated water use and, therefore, the risk from the pathway can be
considered assessed and managed.
EPA has not developed CWA section 304(a) recommended water quality criteria for the
protection of aquatic life for o-dichlorobenzene, so there are no national recommended criteria
for this use available for adoption into state water quality standards and available for use in
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NPDES permits. The Office of Water may issue CWA section 304(a) aquatic life criteria for o-
dichlorobenzene in the future.
2.6.3.3 Disposal and Soil Pathways
o-Dichlorobenzene is included on the list of hazardous wastes pursuant to RCRA 3001 (40 CFR
§§ 261.33) as a listed waste on the U070 lists. The general standard in section RCRA 3004(a) for
the technical criteria that govern the management (treatment, storage, and disposal) of hazardous
waste are those "necessary to protect human health and the environment," RCRA 3004(a). The
regulatory criteria for identifying "characteristic" hazardous wastes and for "listing" a waste as
hazardous also relate solely to the potential risks to human health or the environment (40 CFR §§
261.11, 261.21-261.24). RCRA statutory criteria for identifying hazardous wastes require EPA to
"tak[e] into account toxicity, persistence, and degradability in nature, potential for accumulation
in tissue, and other related factors such as flammability, corrosiveness, and other hazardous
characteristics." Subtitle C controls cover not only hazardous wastes that are landfilled, but also
hazardous wastes that are incinerated (subject to joint control under RCRA Subtitle C and the
Clean Air Act (CAA) hazardous waste combustion Maximum Achievable Control Technology
(MACT)) or injected into Underground Injection Control (UIC) Class I hazardous waste wells
(subject to joint control under Subtitle C and the Safe Drinking Water Act (SDWA)).
TRI reporting in 2018 indicated 15,700 pounds released to underground injection to Class I
hazardous waste wells. Environmental disposal of o-dichlorobenzene injected into Class I
hazardous waste well types fall under the jurisdiction of RCRA and SDWA and disposal of o-
dichlorobenzene via underground injection is not likely to result in environmental and general
population exposures.
EPA has identified releases to land that go to RCRA Subtitle C hazardous waste landfills. Based
on 2018 reporting, the majority of TRI land disposal includes Subtitle C landfills (18,400
pounds) with a much smaller amount transferred to "other landfills" both on-site and off-site (0
pounds in 2018). Design standards for Subtitle C landfills require double liner, double leachate
collection and removal systems, leak detection system, run on, runoff, and wind dispersal
controls, and a construction quality assurance program. They are also subject to closure and post-
closure care requirements including installing and maintaining a final cover, continuing
operation of the leachate collection and removal system until leachate is no longer detected,
maintaining and monitoring the leak detection and groundwater monitoring system. Bulk liquids
may not be disposed in Subtitle C landfills. Subtitle C landfill operators are required to
implement an analysis and testing program to ensure adequate knowledge of waste being
managed, and to train personnel on routine and emergency operations at the facility. Hazardous
waste being disposed in Subtitle C landfills must also meet RCRA waste treatment standards
before disposal. Given these controls, general population exposure to groundwater from Subtitle
C landfill leachate is not expected to be a significant pathway.
o-Dichlorobenzene is present in commercial and consumer products that may be disposed of in
Municipal Solid Waste (MSW) landfills. On-site releases RCRA Subtitle D municipal solid
waste landfills leading to exposures of the general population (including susceptible populations)
or terrestrial species from such releases are expected to be minimal based on current TRI releases
(i.e., 0 lb in 2018) for 1,1,2- trichloroethane. While permitted and managed by the individual
40

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states, municipal solid waste (MSW) landfills are required by federal regulations to implement
some of the same requirements as Subtitle C landfills. MSW landfills generally must have a liner
system with leachate collection and conduct groundwater monitoring and corrective action when
releases are detected. MSW landfills are also subject to closure and post-closure care
requirements and must have financial assurance for funding of any needed corrective actions.
MSW landfills have also been designed to allow for the small amounts of hazardous waste
generated by households and very small quantity waste generators (less than 220 lb per month).
Bulk liquids, such as free solvent, may not be disposed of at MSW landfills.
On-site releases to land from industrial non-hazardous and construction/demolition waste
landfills may occur for o-dichlorobenzene. Industrial non-hazardous and construction/demolition
waste landfills are primarily regulated under authorized state regulatory programs. States must
also implement limited federal regulatory requirements for siting, groundwater monitoring, and
corrective action, and a prohibition on open dumping and disposal of bulk liquids. States may
also establish additional requirements such as for liners, post-closure and financial assurance, but
are not required to do so.
2.6.4 Conceptual Model for Environmental Releases and Wastes: Potential
Exposures and Hazards
As described in Section 2.6.3, some pathways in the conceptual models are covered under the
jurisdiction of other environmental statutes administered by EPA. The conceptual model
depicted in Figure 2-11 presents the exposure pathways, exposure routes and hazards to human
and environmental receptors from releases and wastes from industrial, commercial, and
consumer uses of o-dichlorobenzene that EPA plans to consider in the risk evaluation. The
exposure pathways, exposure routes and hazards presented in this conceptual model are subject
to change in the final scope, in light of comments received on this draft scope and other
reasonably available information. EPA continues to consider whether and how other EPA-
administered statutes and any associated regulatory programs address the presence of o-
dichlorobenzene in exposure pathways falling under the jurisdiction of these EPA statutes.
The diagram shown in Figure 2-11 includes releases from industrial, commercial and/or
consumer uses to water/sediment; biosolids and soil, via direct and indirect discharges to water,
that may lead to exposure to aquatic and terrestrial receptors, and to the general population and
terrestrial species from emissions to air. The supporting basis for environmental pathways
considered for o-dichlorobenzene are included in Appendix H.
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HLLLKStS AMD WASTES J ROM INDl STKIAL/	KXPOSI'RF P UIIW KYS	rVfOSI Rf ROI TFS	RKtPIORS	HAZARDS
C'OMMI'RCI \l C ONM 'MI RI S> S
i. Sediment
Oval
S
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2.7 Analysis Plan
The analysis plan is based on EPA's knowledge of o-dichlorobenzene to date which includes a
partial, but not complete review of identified information as described in Section 2.1. EPA
encourages submission of additional existing data, such as full study reports or workplace
monitoring from industry sources, that may be relevant for further evaluating conditions of use,
exposures, hazards and potentially exposed or susceptible subpopulations during risk evaluation.
Further, EPA may consider any relevant CBI in the risk evaluation in a manner that protects the
confidentiality of the information from public disclosure. EPA plans to continue to consider new
information submitted by the public. Should additional data or approaches become available,
EPA may update its analysis plan in the final scope document.
2.7.1 Physical and Chemical Properties and Environmental Fate
EPA plans to analyze the physical and chemical (p-chem) properties and environmental fate and
transport of o-dichlorobenzene as follows:
1)	Review reasonably available measured or estimated p-chem and environmental fate
endpoint data collected using systematic review procedures and, where available,
environmental assessments conducted by other regulatory agencies.
EPA plans to review data and information collected through the systematic review
methods and public comments about the p-chem properties (Appendix B) and fate
endpoints (Appendix C) previously summarized in the Proposed Designation of o-
Dichlorobenzene fCASRN 95-50-1) as a High-Priority Substance for Risk Evaluation
(U.S. EPA, 2019a). All sources cited in EPA's analysis will be evaluated according to the
procedures described in the systematic review documentation that EPA plans to publish
prior to finalizing the scope document. Where the systematic review process fails to
identify experimentally measured chemical property values of sufficiently high quality,
these values will be estimated using chemical parameter estimation models as
appropriate. Model-estimated fate properties will be reviewed for applicability and
quality.
2)	Using measured data and/or modeling, determine the influence of p-chem and
environmental fate endpoints (e.g., persistence, bioaccumulation, partitioning,
transport) on exposure pathways and routes of exposure to human and
environmental receptors.
Measured data and, where necessary, model predictions of physical-chemical properties
and environmental fate endpoints will be used to characterize the persistence and
movement of o-dichlorobenzene within and across environmental media. The fate
endpoints of interest include volatilization, sorption to organic matter in soil and
sediments, water solubility, aqueous and atmospheric photolysis rates, aerobic and
anaerobic biodegradation rates, and potential bioconcentration and bioaccumulation.
These endpoints will be used in exposure calculations.
3)	Conduct a weight-of-evidence evaluation of p-chem and environmental fate data,
including qualitative and quantitative sources of information.
During risk evaluation, EPA plans to evaluate and integrate the environmental fate
evidence identified in the literature inventory using the methods described in the
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systematic review documentation that EPA plans to publish prior to finalizing the scope
document.
2,7.2 Exposure
EPA plans to analyze exposure levels for indoor air, ambient air, surface water, sediment, soil,
ground water, dietary food sources, aquatic biota, and terrestrial biota associated to exposure to
o-dichlorobenzene. EPA has not yet determined the exposure levels in these media or how they
may be used in the risk evaluation. Exposure scenarios are combinations of sources (uses),
exposure pathways, and exposed receptors. Draft release/exposure scenarios corresponding to
various conditions of use for o-dichlorobenzene are presented in 2.8 Appendix E. EPA plans to
analyze scenario-specific exposures.
Based on their physical-chemical properties, expected sources, and transport and transformation
within the outdoor and indoor environment, chemical substances are more likely to be present in
some media and less likely to be present in others. Exposure level(s) can be characterized
through a combination of available monitoring data and modeling approaches.
2.7.2.1 Environmental Releases
EPA expects to analyze releases to environmental media as follows:
1)	Review reasonably available published literature and other reasonably available
information on processes and activities associated with the conditions of use to
analyze the types of releases and wastes generated.
EPA has reviewed some sources containing information on processes and activities
resulting in releases, and the information found is described in Appendix E. EPA plans to
review additional data sources identified. Potential sources of environmental release data
are summarized in Table 2-5below:
Table 2-5 Categories and Sources of Environmental Release Data	
U.S. EPA TRI Data	
U.S. EPA Generic Scenarios	
OECD Emission Scenario Documents	
EU Risk Assessment Reports	
Discharge Monitoring Report (DMR) surface water discharge data for o-
dichlorobenzene from NPDES-permitted facilities	
2)	Review reasonably available chemical-specific release data, including measured or
estimated release data (e.g., data from risk assessments by other environmental
agencies).
EPA has reviewed key release data sources including the Toxics Release Inventory
(TRI), and the data from this source is summarized in Section 2.3.3. EPA plans to
continue to review relevant data sources during risk evaluation. EPA plans to match
identified data to applicable conditions of use and identify data gaps where no data are
found for particular conditions of use. EPA plans to attempt to address data gaps
identified as described in steps 3 and 4 below by considering potential surrogate data and
models.
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Additionally, for conditions of use where no measured data on releases are available,
EPA may use a variety of methods including release estimation approaches and
assumptions in the Chemical Screening Tool for Occupational Exposures and Releases
ChemSTEER (U.S. EPA. 2013Y
3)	Review reasonably available release data for surrogate chemicals that have similar
uses and physical properties.
EPA plans to review literature sources identified and if surrogate data are found, these
data will be matched to applicable conditions of use for potentially filling data gaps.
4)	Review reasonably available data that may be used in developing, adapting or
applying release models to the particular risk evaluation.
This item will be performed after completion of #2 and #3 above. EPA plans to evaluate
relevant data to determine whether the data can be used to develop, adapt or apply models
for specific conditions of use (and corresponding release scenarios). EPA has identified
information from various EPA statutes (including, for example, regulatory limits,
reporting thresholds or disposal requirements) that may be relevant to release estimation.
EPA plans to further consider relevant regulatory requirements in estimating releases
during risk evaluation.
5)	Review and determine applicability of OECD Emission Scenario Documents (ESDs)
and EPA Generic Scenarios to estimation of environmental releases.
EPA has identified potentially relevant OECD Emission Scenario Documents (ESDs) and
EPA Generic Scenarios (GS) that correspond to some conditions of use; for example, the
July 2009 ESP on Plastics Additives (OECD, 2009) and the September 2 Don
Chemical Industry (OECD, 2011) may be useful. EPA plans to need to critically review
these generic scenarios and ESDs to determine their applicability to the conditions of use
assessed.
EPA Generic Scenarios are available at the following: https://www.epa.gov/tsca-
screening-tools/using-predictive-methods-assess-exposure-and-fate-under-tsca#fate.
OECD Emission Scenario Documents are available at the following:
http://www.oecd.ore/chemlcalsafety/risk-assessm.ent/em.ission.scenariodociim.ents.htm
6)	Map or group each condition of use to a release assessment scenario(s).
EPA has identified release scenarios and mapped (i.e. grouped) them to relevant
conditions of use as shown in Appendix F. EPA was not able to identify release scenarios
corresponding to some conditions of use (e.g. recycling, construction and demolition).
EPA plans to perform targeted research to understand those uses, which may inform
identification of release scenarios. EPA may further refine the mapping/grouping of
release scenarios based on factors (e.g., process equipment and handling, magnitude of
production volume used, and exposure/release sources) corresponding to conditions of
use as additional information is identified during risk evaluation.
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7) Evaluate the weight of the scientific evidence of environmental release data.
During risk evaluation, EPA plans to evaluate and integrate the environmental release
evidence identified in the literature inventory using the methods described in the
systematic review documentation that EPA plans to publish prior to finalizing the scope
document. The data integration strategy will be designed to be fit-for-purpose in which
EPA plans to use systematic review methods to assemble the relevant data, evaluate the
data for quality and relevance, including strengths and limitations, followed by synthesis
and integration of the evidence.
2.7.2.2 Environmental Exposures
EPA plans to analyze the following in developing its environmental exposure assessment of o-
dichlorobenzene:
1)	Review reasonably available environmental and biological monitoring data for all
media relevant to environmental exposure.
For o-dichlorobenzene, environmental media which will be analyzed are sediment, soil,
air and water.
2)	Review reasonably available information on releases to determine how modeled
estimates of concentrations near industrial point sources compare with available
monitoring data.
Available environmental exposure models that meet the TSCA Science Standards and
that estimate surface water, sediment, and soil concentrations will be analyzed and
considered alongside available surface water, sediment, and soil monitoring data to
characterize environmental exposures. Modeling approaches to estimate surface water
concentrations, sediment concentrations and soil concentrations generally consider the
following inputs: direct release into surface water, sediment, or soil, indirect release into
surface water, sediment, or soil (i.e., air deposition), fate and transport (partitioning
within media) and characteristics of the environment (e.g., river flow, volume of lake,
meteorological data).
3)	Determine applicability of existing additional contextualizing information for any
monitored data or modeled estimates during risk evaluation.
There have been changes to use patterns of o-dichlorobenzene over the last few years.
Monitoring data or modeled estimates will be reviewed to determine how representative
they are of ongoing use patterns.
Any studies which relate levels of o-dichlorobenzene in the environment or biota with
specific sources or groups of sources will be evaluated.
4)	Group each condition(s) of use to environmental assessment scenario(s).
Refine and finalize exposure scenarios for environmental receptors by considering
combinations of sources (use descriptors), exposure pathways including routes, and
populations exposed. For o-dichlorobenzene, the following are noteworthy considerations
in constructing exposure scenarios for environmental receptors:
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Estimates of surface water concentrations, sediment concentrations and soil
concentrations near industrial point sources based on available monitoring
data.
Generally, consider the following modeling inputs: release into the media of
interest, fate and transport and characteristics of the environment.
Reasonably available biomonitoring data. Monitoring data could be used to
compare with species or taxa-specific toxicological benchmarks.
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 the extent that data are
available, and characterize exposed aquatic and terrestrial populations.
Weight of the scientific evidence of environmental occurrence data and
modeled estimates.
5) Evaluate the weight of the scientific evidence of environmental occurrence data and
modeled estimates.
During risk evaluation, EPA plans to evaluate and integrate the exposure evidence
identified in the literature inventory using the methods described in the systematic review
documentation that EPA plans to publish prior to finalizing the scope document.
2.7.2.3 Occupational Exposures
EPA expects to analyze both worker and occupational non-user exposures as follows:
1) Review reasonably available exposure monitoring data for specific condition(s) of
use.
EPA expects to review exposure data including 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. These workplace monitoring data include
personal exposure monitoring data (direct exposures) and area monitoring data (indirect
exposures). EPA has preliminarily reviewed available monitoring data collected by
OSHA and NIOSH and will match these data to applicable conditions of use.
OSHA has established a permissible exposure limit (PEL) for o-dichlorobenzene. EPA
plans to consider the influence of such limits on occupational exposures in the
occupational exposure assessment. The following are some data sources identified thus
far:
Table 2-6 Potential Sources of Occupational Exposure Data
2012 ATSDR Toxicological Profile	
U.S. OSHA Chemical Exposure Health Data (CEHD) program data
U.S. NIOSH Health Hazard Evaluation (HHE) Program reports
2) Review reasonably available exposure data for surrogate chemicals that have uses,
volatility and chemical and physical properties similar to o-dichlorobenzene.
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EPA plans to review literature sources identified and if surrogate data are found, these
data will be matched to applicable conditions of use for potentially filling data gaps.
3)	For conditions of use where data are limited or not available, review existing exposure
models that may be applicable in estimating exposure levels.
EPA has identified potentially relevant OECD ESDs and EPA GS corresponding to some
conditions of use. For example, the April 2004 Spray Coatings in the Furniture Industry
GS (EPA, 2004) and the September 2001 Manufacture and U se of Printing Ink G S (EPA,
2001) are some of the ESDs and GS's that EPA may use to estimate occupational
exposures. EPA plans to critically review these generic scenarios and ESDs to determine
their applicability to the conditions of use. EPA plans to perform additional targeted
research to understand those conditions of use, which may inform identification of
exposure scenarios. EPA may also need to perform targeted research to identify
applicable models that EPA may use to estimate exposures for certain conditions of use.
4)	Review reasonably available data that may be used in developing, adapting or applying
exposure models to a particular risk evaluation scenario.
This step will be performed after Steps #1 and #2 are completed. Based on information
developed from Steps #2 and #3, EPA plans to evaluate relevant data to determine
whether the data can be used to develop, adapt, or apply models for specific conditions of
use (and corresponding exposure scenarios). EPA may utilize existing, peer-reviewed
exposure models developed by EPA/OPPT, other government agencies, or available in
the scientific literature, or EPA may elect to develop additional models to assess specific
condition(s) of use. Inhalation exposure models may be simple box models or two-zone
(near-field/far-field) models. In two-zone models, the near-field exposure represents
potential inhalation exposures to workers, and the far-field exposure represents potential
inhalation exposures to ONUs.
5)	Consider and incorporate applicable engineering controls and/or personal
protective equipment into exposure scenarios.
EPA plans to review potentially relevant data sources on EC and PPE to determine their
applicability and incorporation into exposure scenarios during risk evaluation. EPA plans
to assess worker exposure pre- and post-implementation of engineering controls, using
reasonably available information on control technologies and control effectiveness. For
example, EPA may assess worker exposure in industrial use scenarios before and after
implementation of local exhaust ventilation.
6)	Map or group each condition of use to occupational exposure assessment scenario(s).
EPA may group occupational exposure scenarios based on factors (e.g., process
equipment and handling, magnitude of production volume used, and exposure/release
sources) corresponding to conditions of use as additional information is identified during
risk evaluation.
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7) Evaluate the weight of the scientific evidence of occupational exposure data, which
may include qualitative and quantitative sources of information.
During risk evaluation, EPA plans to evaluate and integrate the exposure evidence
identified in the literature inventory using the methods described in the systematic review
documentation that EPA plans to publish prior to finalizing the scope document. EPA
plans to rely on the weight of the scientific evidence when evaluating and integrating
occupational data. The data integration strategy will be designed to be fit-for-purpose in
which EPA plans to use systematic review methods to assemble the relevant data,
evaluate the data for quality and relevance, including strengths and limitations, followed
by synthesis and integration of the evidence.
2.7.2.4 Consumer Exposures
EPA plans to analyze both consumers using a consumer product and bystanders associated with
the consumer using the product as follows:
1)	Group each condition of use to consumer exposure assessment scenario(s).
Refine and finalize exposure scenarios for consumers by considering combinations of
sources (ongoing consumer uses), exposure pathways including routes, and exposed
populations.
For o-dichlorobenzene, the following are noteworthy considerations in constructing
consumer exposure scenarios:
Conditions of use
Duration of exposure
Weight fraction of chemical in products
Amount of chemical used
2)	Evaluate the relative potential of indoor exposure pathways based on available data.
Indoor exposure pathways expected to be relatively higher include inhalation of vapors
and mists from indoor air during o-dichlorobenzene use and disposal. Indoor exposure
pathways expected to be relatively lower include dermal contact to solid and liquid o-
dichlorobenzene. The data sources associated with these respective pathways have not
been comprehensively evaluated, so quantitative comparisons across exposure pathways
or in relation to toxicity thresholds are not yet available.
3)	Review existing indoor exposure models that may be applicable in estimating indoor
air.
Indoor exposure models that estimate emission and migration of SVOCs into the indoor
environment are available. These models generally consider mass transfer as informed by
the gas-phase mass transfer coefficient, the solid-phase diffusion coefficient, and the
material-air partition coefficient. These properties vary based on physical-chemical
properties and properties of the material. The OPPT's Indoor Environmental
Concentrations in Buildings with Conditioned and Unconditioned Zones (IECCU) model
and other similar models can be used to estimate indoor air and dust exposures from
indoor sources.
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4)	Review reasonably available empirical data that may be used in developing,
adapting or applying exposure models to a particular risk evaluation scenario. For
example, existing models developed for a chemical assessment may be applicable to
another chemical assessment if model parameter data are available.
To the extent other organizations have already modeled a o-dichlorobenzene consumer
exposure scenario that is relevant to the OPPT's assessment, EPA plans to evaluate those
modeled estimates. In addition, if other chemicals similar to o-dichlorobenzene have been
modeled for similar uses, those modeled estimates will also be evaluated. The underlying
parameters and assumptions of the models will also be evaluated.
5)	Review reasonably available consumer product-specific sources to determine how
those exposure estimates compare with each other and with indoor monitoring data
reporting o-dichlorobenzene in specific media (e.g., indoor air).
The availability of o-dichlorobenzene concentration for various ongoing uses will be
evaluated. This data provides the source term for any subsequent indoor modeling.
Source attribution between overall indoor air and dust levels and various indoor sources
will be analyzed.
6)	Review reasonably available population- or subpopulation-specific exposure factors
and activity patterns to determine if potentially exposed or susceptible
subpopulations need to be further refined.
During risk evaluation, EPA plans to evaluate and integrate the exposure evidence
identified in the literature inventory using the methods described in the systematic review
documentation that EPA plans to publish prior to finalizing the scope document.
7)	Evaluate the weight of the scientific evidence of consumer exposure estimates based
on different approaches.
EPA plans to rely on the weight of the scientific evidence when evaluating and
integrating data related to consumer exposure. The weight of the scientific evidence may
include qualitative and quantitative sources of information. The data integration strategy
will be designed to be fit-for-purpose in which EPA plans to use systematic review
methods to assemble the relevant data, evaluate the data for quality and relevance,
including strengths and limitations, followed by synthesis and integration of the evidence.
2.7.2.5 General Population
EPA plans to analyze general population exposures as follows:
1) Refine and finalize exposure scenarios for general population by considering sources
and uses, exposure pathways including routes, and exposed populations.
For o-dichlorobenzene, the following are noteworthy considerations in constructing
exposure scenarios for the general population:
Review reasonably available environmental and biological monitoring data for
media to which general population exposures are expected.
For exposure pathways where data are not available, review existing exposure
models that may be applicable in estimating exposure levels.
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Consider and incorporate applicable media-specific regulations into exposure
scenarios or modeling.
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.
Review reasonably available information on releases to determine how modeled
estimates of concentrations near industrial point sources compare with available
monitoring data.
Review reasonably available population- or subpopulation-specific exposure
factors and activity patterns to determine if potentially exposed or susceptible
subpopulations need be further defined.
Evaluate the weight of the scientific evidence of general population exposure
data.
Map or group each condition of use to general population exposure assessment
scenario(s).
Environmental Exposure pathways regulated by non-TSCA EPA laws and
regulations will be excluded from analysis
EPA plans to evaluate a variety of data types to determine which types are most
appropriate when quantifying exposure scenarios. Environmental monitoring data,
biomonitoring data, modeled estimates, experimental data, epidemiological data, and
survey-based data can all be used to quantify exposure scenarios. In an effort to associate
exposure estimates with sources of exposure and/or conditions of use, EPA plans to
consider source apportionment across exposure scenarios during risk evaluation. EPA
anticipates that there will be a wide range in the relative exposure potential of the
exposure scenarios identified in Section 2.6. Source apportionment characterizes the
relative contribution of any of the following: a use/source toward a total media
concentration, a media concentration toward a total exposure route, or an exposure route
toward a total external or internal dose. This consideration may be qualitative, semi-
quantitative, or quantitative, and is dependent upon available data and approaches. For
example, EPA may consider the co-location of TSCA industrial facilities with available
monitoring data or modeled estimates. EPA may compare modeled estimates for discrete
outdoor and indoor sources/uses that apply to unique receptor groups. If available, EPA
plans to compare multiple scenario-specific and background exposure doses estimated
from media-specific concentrations and exposure factors with available biomonitoring
data. The forward-calculated and back-calculated exposures could be compared to
characterize the relative contribution from defined exposure scenarios.
After refining and finalizing exposure scenarios, EPA plans to quantify concentrations
and/or doses for these scenarios. The number of scenarios will depend on how unique
combinations of uses, exposure pathways, and receptors are characterized. The number of
scenarios is also dependent upon the available data and approaches to quantify scenarios.
When quantifying exposure scenarios, EPA plans to use a tiered approach. First-tier
analysis is based on data that is readily available without a significant number of
additional inputs or assumptions, and may be qualitative, semi-quantitative, or
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quantitative. The results of first tier analyses inform whether scenarios require more
refined analysis. Refined analyses will be iterative and require careful consideration of
variability and uncertainty. Should data become available that summarily alters the
overall conclusion of a scenario through iterative tiering, EPA can refine its analysis
during risk evaluation.
2)	For exposure pathways where empirical data is not available, review existing
exposure models that may be applicable in estimating exposure levels.
For o-dichlorobenzene, media where exposure models will be considered for general
population exposure include models that estimate ambient air concentrations, surface
water concentrations, sediment concentrations, soil concentrations, and uptake from
aquatic and terrestrial environments into edible aquatic and terrestrial organisms.
3)	Review available exposure modeled estimates. For example, existing models
developed for a previous o-dichlorobenzene chemical assessment may be applicable
to EPA's assessment. In addition, another chemical's assessment may also be
applicable if model parameter data are available.
To the extent other organizations have already modeled o-dichlorobenzene general
population exposure scenario that is relevant to the OPPT's assessment, EPA plans to
evaluate those modeled estimates. In addition, if modeled estimates for other chemicals
with similar physical chemical properties and similar uses are available, those modeled
estimates will also be evaluated. The underlying parameters and assumptions of the
models will also be evaluated.
4)	Review reasonably available information on releases to determine how modeled
estimates of concentrations near industrial point sources compare with available
monitoring data.
The expected releases from industrial facilities are changing over time. Any modeled
concentrations based on recent release estimates will be carefully compared with
available monitoring data to determine representativeness.
5)	Review reasonably available information about population- or subpopulation-
specific exposure factors and activity patterns to determine if potentially exposed or
susceptible subpopulations need to be further defined (e.g., early life and/or puberty
as a potential critical window of exposure).
For o-dichlorobenzene, exposure scenarios that involve potentially exposed or susceptible
subpopulations will consider age-specific behaviors, activity patterns, and exposure
factors unique to those subpopulations. For example, children will have different intake
rates for dust, soil, and diet than adults.
6)	Evaluate the weight of the scientific evidence of general population exposure
estimates based on different approaches.
During risk evaluation, EPA plans to evaluate and integrate the exposure evidence
identified in the literature inventory using the methods described in the systematic review
documentation that EPA plans to publish prior to finalizing the scope document.
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2.7.3 Hazards (Effects)
2.7.3.1 Environmental Hazards
EPA plans to conduct an environmental hazard assessment of o-dichlorobenzene as follows:
1)	Review reasonably 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).
EPA plans to analyze the hazards of o-dichlorobenzene to aquatic and/or terrestrial
organisms, including plants, invertebrates (e.g., insects, arachnids, mollusks,
crustaceans), and vertebrates (e.g., mammals, birds, amphibians, fish, reptiles) across
exposure durations and conditions if potential environmental hazards are identified
through systematic review results and public comments. Additional types of
environmental hazard information will also be considered (i.e., analogue and read-across
data) when characterizing the potential hazards of o-dichlorobenzene to aquatic and/or
terrestrial organisms.
Environmental hazard data will be evaluated using the environmental toxicity data
quality criteria outlined in the systematic review documentation that EPA plans to publish
prior to finalizing the scope document. The study evaluation results will be documented
in the risk evaluation phase and data from suitable studies will be extracted and integrated
in the risk evaluation process.
2)	Derive hazard thresholds for aquatic and/or terrestrial organisms.
Depending on the robustness of the evaluated data for a particular organism or taxa (e.g.,
aquatic invertebrates), environmental hazard values (e.g., ECx. LCx, NOEC, LOEC) may
be derived and used to further understand the hazard characteristics of p-dichlorobenzene
to aquatic and/or terrestrial species. Identified environmental hazard thresholds may be
used to derive concentrations of concern (COC), based on endpoints that may affect
populations of organisms or taxa analyzed.
3)	Evaluate the weight of the scientific evidence of environmental hazard data.
During risk evaluation, EPA plans to evaluate and integrate the environmental hazard
evidence identified in the literature inventory using the methods described in the
systematic review documentation that EPA plans to publish prior to finalizing the scope
document.
4)	Consider the route(s) of exposure, based on available monitoring and modeling data
and other available approaches to integrate exposure and hazard assessments.
EPA plans to consider aquatic (e.g., water and sediment exposures) and terrestrial
pathways in the o-dichlorobenzene conceptual model. These organisms may be exposed
to p-dichlorobenzene via a number of environmental pathways (e.g., surface water,
sediment, soil, diet).
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5)	Conduct an environmental risk characterization of o-dichlorobenzene.
EPA plans to conduct a risk characterization of o-dichlorobenzene to identify if there are
risks to the aquatic and/or terrestrial environments from the measured and/or predicted
concentrations of chemical name in environmental media (i.e., water, sediment, soil).
Risk quotients (RQs) may be derived by the application of hazard and exposure
benchmarks to characterize environmental risk (	M; Barnthouse et al..
1982).
6)	Consider a Persistent, Bioaccumulative, and Toxic (PBT) Assessment of o-
dichlorobenzene.
EPA plans to consider the persistence, bioaccumulation, and toxic (PBT) potential of o-
dichlorobenzene after reviewing relevant physical-chemical properties and exposure
pathways. EPA plans to assess the available studies collected from the systematic review
process relating to bioaccumulation and bioconcentration (e.g., BAF, BCF) of o-
dichlorobenzene. In addition, EPA plans to integrate traditional environmental hazard
endpoint values (e.g., LCso, LOEC) and exposure concentrations (e.g., surface water
concentrations, tissue concentrations) for p-dichlorobenzene with the fate parameters
(e.g., BAF, BCF, BMF, TMF).
2.7.3.2 Human Health Hazards
EPA plans to 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).
Human health studies will be evaluated using the evaluation strategies laid out in the
systematic review documentation that EPA plans to publish prior to finalizing the scope
document.
Mechanistic data may include analyses of alternative test data such as novel in vitro test
methods and high throughput screening. The association between acute and chronic
exposure scenarios to the agent and each health outcome will also be integrated. Study
results will be extracted and presented in evidence tables or another appropriate format
by organ/system
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.
Reasonably available human health hazard data will be evaluated to ascertain whether
some human receptor groups may have greater susceptibility than the general population
to o-dichlorobenzene hazard(s). Susceptibility of particular human receptor groups to o-
dichlorobenzene will be determined by evaluating information on factors that influence
susceptibility.
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EPA has reviewed some sources containing hazard information associated with
susceptible populations and lifestages such as pregnant women and infants. Pregnancy
(i.e., gestation) and childhood are potential susceptible lifestages for o-dichlorobenzene
exposure. Pregnancy (i.e., gestation) and childhood are potential susceptible lifestages for
o-dichlorobenzene exposure. EPA plans to review the current state of the literature in
order to potentially quantify these differences for risk evaluation purposes.
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 identified human health hazard endpoints.
Human health hazards from acute and chronic exposures will be identified by evaluating
the human and animal data that meet the systematic review data quality criteria described
in the systematic review documentation that EPA plans to publish prior to finalizing the
scope document. Hazards identified by studies meeting data quality criteria will be
grouped by routes of exposure relevant to humans (oral, dermal, inhalation) and by
cancer and noncancer endpoints.
Dose-response assessment will be performed in accordance with EPA guidance (U.S.
EPA. 2.012a. 2.011. 1994). Dose-response analyses may be used if the data meet data
quality criteria and if additional information on the identified hazard endpoints are not
available or would not alter the analysis.
The cancer mode of action (MOA) determines how cancer risks can be quantitatively
evaluated. If cancer hazard is determined to be applicable to o-dichlorobenzene, EPA
plans to evaluate information on genotoxicity and the mode of action for all cancer
endpoints to determine the appropriate approach for quantitative cancer assessment in
accordance with the U.S. EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA...
2005).
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.
Hazard data will be evaluated to determine the type of dose-response modeling that is
applicable. Where modeling is feasible, a set of dose-response models that are consistent
with a variety of potentially underlying biological processes will be applied to
empirically model the dose-response relationships in the range of the observed data
consistent with EPA's Benchmark Dose Technical Guidance Document. Where dose-
response modeling is not feasible, NOAELs or LOAELs will be identified. Non-
quantitative data will also be evaluated for contribution to weight of the scientific
evidence or for evaluation of qualitative endpoints that are not appropriate for dose-
response assessment.
EPA plans to evaluate whether the available PBPK and empirical kinetic models are
adequate for route-to-route and interspecies extrapolation of the POD, or for
extrapolation of the POD to standard exposure durations (e.g., lifetime continuous
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exposure). If application of the PBPK model is not possible, oral PODs may be adjusted
by BW3 4 scaling in accordance with U.S. EPA. (2011). and inhalation PODs may be
adjusted by exposure duration and chemical properties in accordance with U.S. EPA.
(1994).
5)	Evaluate the weight of the scientific evidence of human health hazard data.
During risk evaluation, EPA plans to evaluate and integrate the human health hazard
evidence identified in the literature inventory under acute and chronic exposure
conditions using the methods described in the systematic review documentation that EPA
plans to publish prior to finalizing the scope document.
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.
At this stage of review, EPA believes there will be sufficient data to conduct dose-
response analysis and/or benchmark dose modeling for the oral route of exposure. EPA
plans to also evaluate any potential human health hazards following dermal and
inhalation exposure to o-dichlorobenzene, which could be important for worker,
consumer, and general population risk analysis. Available data will be assessed to
determine whether or not a point of departure can be identified for the dermal and
inhalation routes. This may include using route-to-route extrapolation methods where
appropriate and depending on the nature of available data.
If sufficient toxicity studies are not identified in the literature search to assess risks from
dermal and inhalation exposures, then a route-to-route extrapolation from oral toxicity
studies would be needed to assess systemic risks from dermal or inhalation exposures.
Without an adequate PBPK model, the approaches described in EPA guidance document
Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual
(Part E, Supplemental Guidance for Dermal Risk Assessment) (	MM) could be
applied to extrapolate from oral to dermal exposure. These approaches may be able to
further inform the relative importance of dermal exposures compared with other routes of
exposure. Similar methodology may also be used for assessing inhalation exposures
2.7.4 Summary of Risk Approaches for Characterization
Risk characterization is an integral component of the risk assessment process for both
environmental and human health risks. EPA plans to derive the risk characterization in
accordance with EPA's Risk Characterization Handbook (U.S. EPA. 2000). As defined in 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.
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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 (	00) and consistent with the
requirements of the Procedures for Chemical Risk Evaluation Under the Amended Toxic
Substances Control Act (82 FR 33726). For instance, in the risk characterization summary, EPA
plans to further carry out the obligations under TSCA section 26; for example, by identifying and
assessing uncertainty and variability in each step of the risk evaluation, discussing considerations
of data quality such as the reliability, relevance and whether the methods utilized were
reasonable and consistent, explaining any assumptions used, and discussing information
generated from independent peer review.
EPA plans to also be guided by EPA's Information Quality Guidelines (TJ.S EPA. 2002) as it
provides guidance for presenting risk information. Consistent with those guidelines, in the risk
characterization, EPA plans to also identify: (1) Each population addressed by an estimate of
applicable risk effects; (2) the expected risk or central estimate of risk for the potentially exposed
or susceptible subpopulations affected; (3) each appropriate upper-bound or lower bound
estimate of risk; (4) each significant uncertainty identified in the process of the assessment of
risk effects and the studies that would assist in resolving the uncertainty; and (5) peer reviewed
studies known to the Agency that support, are directly relevant to, or fail to support any estimate
of risk effects and the methodology used to reconcile inconsistencies in the scientific
information.
2.8 Peer Review
Peer review will be conducted in accordance with EPA's regulatory procedures for chemical risk
evaluations, including using EPA's Peer Review Handbook and other methods consistent with
section 26 of TSCA (See 40 CFR 702.45). As explained in the Risk Evaluation Rule, the purpose
of peer review is for the independent review of the science underlying the risk assessment. Peer
review will therefore address aspects of the underlying science as outlined in the charge to the
peer review panel such as hazard assessment, assessment of dose-response, exposure assessment,
and risk characterization. The draft risk evaluation for o-dichlorobenzene will be peer reviewed).
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Triangle Park, NC: U.S. Department of Health and Human Services, National Institutes of
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Oliver, BG;Niimi, AJ. (1985). Bioconcentration factors of some halogenated organics for
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assessment [EPA Report], (EPA/630/R-95/002F). Washington, DC: U.S. Environmental
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high production volume (HPV) chemicals: Chlorobenzenes category: Sponsored chemicals:
Monochlorobenzene (CASRN 108-90-7) (CA Index Name: Benzene, chloro-); 1,2-
Dichlorobenzene (CASRN 95-50-1) (CA Index Name: Benzene, 1,2-dichloro-); 1,3-
Dichlorobenzene (CASRN 541-73-1) (CA Index Name: Benzene, 1,3-dichloro-); 1,2,3-
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Assessment Forum, https://www.epa.gov/risk/benchmark-dose-technical-guidance. HERO ID:
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prioritization of chemical substances for risk evaluation: Definitions. Washington, DC. HERO
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Chemical Substance Risk Evaluations: Peer review. Washington, DC. HERO ID: 6302780
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U.S. EPA. (U.S. Environmental Protection Agency). (2018b). ECOTOX Knowledgebase. HERO
ID:4263024
U.S. EPA (U.S. Environmental Protection Agency). (2019a). Proposed Designation of o-
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Chemical Safety and Pollution Prevention, https://www.epa.eov/sites/production/files/2019-
08/documents/o-dichlorobenzene 95- ligh-priority proposeddesignation 082319j>df.
HERO ID: 6305350
U.S. EPA (U.S. Environmental Protection Agency) (2019b). Chemical Data
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U.S. EPA. (U.S. Environmental Protection Agency). (2019d). Envirofacts Toxics Release
Inventory 2017 Updated Dataset (released April 2019) [Website],
https://www.epa.gov/enviro/tri- customized-search. HERO ID: 6127841
U.S. NLM. (2008). HSDB: 1,2-Dichlorobenzene U.S. National Library of Medicine, Hazardous
Substances Data Bank, https://toxnet.nlm.nih.gov/cgi-
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Ukeles, R. (1962). Growth of pure cultures of marine phytoplankton in the presence of toxicants.
Appl Microbiol 10: 532-537. https://www.ncbi.nlm.nih.gov/pubmed/13995259. HERO ID:
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Willert Home Products Inc. (2017). Safety Data Sheet - Enoz Para Moth Balls.
https://images.homedepot-static.com/catalog/pdfImages/35/35c4clc5-ef89-4350-879d-
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Yalkowsky, SH;He, Y;Jain, P. (2010). Handbook of aqueous solubility data (2nd ed.). Boca
Raton, FL: CRC Press. http://dx.doi.org/10.1201/EBK1439802458. HERO ID: 2990992
65

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APPENDICES
Appendix A LIST OF GRAY LITERATURE SOURCES
Table Apx A-l provides a list of gray literature sources that yielded results for o-
dichlorobenzene
Table Apx A-l. Gray Literature Sources That Yielded Results for o-Dich
Source/A yency
Source Vimc
Source Typo
Source
("silej»orv
AT SDR
ATSDR Tox Profile Updates and
Addendums
Other US
Agency
Resources
Assessment
or Related
Document
AT SDR
ATSDR Toxicological Profiles
(original publication)
Other US
Agency
Resources
Assessment
or Related
Document
Australian
Government;
Department of
Health
NICNAS Assessments (human health.
Tier I, 11 or III)
International
Resources
Assessment
or Related
Document
CAL EPA
Technical Support Documents for
regulations: Drinking Water Public
Health Goals
Other US
Agency
Resources
Assessment
or Related
Document
CDC
CDC Biomonitoring Tables
Other US
Agency
Resources
Database
ECHA
ECHA Documents
International
Resources
Assessment
or Related
Document
Env Canada
Priority Substances List Assessment
Report; State of Science Report,
Environment Canada Assessment
International
Resources
Assessment
or Related
Document
Env Canada
Chemicals at a Glance (fact sheets)
International
Resources
Assessment
or Related
Document
Env Canada
Guidelines, Risk Management,
Regulations
International
Resources
Assessment
or Related
Document
EPA
Office of Water: STORET and WQX
US EPA
Resources
Database
orobenzene
66

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Source/A "ency
Source Vtme
Source Type
Source
CsileRory
EPA
EPA Office of Water: Ambient Water
Quality Criteria documents
US EPA
Resources
Assessment
or Related
Document
EPA
Office of Air: TRI
US EPA
Resources
Database
EPA
TSCA Data Needs Assessments or
Problem Formulation
US EPA
Resources
Assessment
or Related
Document
EPA
TSCA Hazard Characterizations
US EPA
Resources
Assessment
or Related
Document
EPA
Other EPA: Misc sources
US EPA
Resources
General
Search
EPA
EPA: AP-42
US EPA
Resources
Regulatory
Document
or List
EPA
TRI: Envirofacts Toxics Release
Inventory 2017 Updated Dataset
US EPA
Resources
Database
EPA
Chemical Data Reporting (2012 and
2016 non-CBI CDR database)
US EPA
Resources
Database
EPA
Chemical Data Reporting (2012 and
2016 CBI CDR database)
US EPA
Resources
Database
EPA
EPA: Generic Scenario
US EPA
Resources
Assessment
or Related
Document
EPA
EPA Discharge Monitoring Report
Data
US EPA
Resources
Database
EPA
Office of Water: Drinking Water
Standards Health Effects Support
Documents
US EPA
Resources
Regulatory
Document
or List
EPA
Office of Air: National Emissions
Inventory (NE1) - National Emissions
Inventory (NE1) Data (2014, 201 1,
2008)
US EPA
Resources
Database
EPA
Office of Air: CFRs and Dockets
US EPA
Resources
Regulatory
Document
or List
67

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Source/A "ency
Source Vtme
Source Type
Source
CsileRory
FDA
FDA Market Baskets
Other US
Agency
Resources
Assessment
or Related
Document
I ARC
I ARC Monograph
International
Resources
Assessment
or Related
Document
Japan
Japanese Ministry of the Environment
Assessments - Environmental Risk
Assessments
International
Resources
Assessment
or Related
Document
Japan
Japanese Ministry of the Environment
Assessments - Environmental Risk
Assessments (Class I Designated
Chemical Substances Summary Table)
International
Resources
Regulatory
Document
or List
KOECT
Kirk-Othmer Encyclopedia of
Chemical Technology Journal Article
Other
Resource
Encyclopedi
a
NIOSH
CDC NIOSH - Occupational Health
Guideline Documents
Other US
Agency
Resources
Assessment
or Related
Document
NIOSH
CDC NIOSH - Pocket Guides
Other US
Agency
Resources
Database
NIOSH
CDC NIOSH - Health Hazard
Evaluations (HHEs)
Other US
Agency
Resources
Assessment
or Related
Document
NLM
National Library of Medicine's
Hazardous Substance Databank
Other US
Agency
Resources
Database
NLM
National Library of Medicine's
HazMap
Other US
Agency
Resources
Database
NTP
Technical Reports
Other US
Agency
Resources
Assessment
or Related
Document
OECD
OECD S1DS
International
Resources
Assessment
or Related
Document
OECD
OECD Emission Scenario Documents
International
Resources
Assessment
or Related
Document
68

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Source/A«encv
Source Nsime
Source Type
Source
CsileRorv
OECD
OECD: General Site
International
Resources
General
Search
OSHA
OSHA Chemical Exposure Health Data
Other US
Agency
Resources
Database
OSHA
U.S. OSHA Chemical Exposure Health
Data (CEHD) program data [ERG]
Other US
Agency
Resources
Database
RIVM
Integrated Critera Documents
International
Resources
Assessment
or Related
Document
RIVM
RIVM Reports: Risk Assessments
International
Resources
Assessment
or Related
Document
TERA
Toxicology Excellence for Risk
Assessment
Other
Resources
Assessment
or Related
Document
69

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Appendix B PHYSICAL AND CHEMICAL PROPERTIES OF o-
DICHLOROBENZENE
This appendix provides p-chem information and data found in preliminary data gathering for o-
dichlorobenzene. Table Apx B-l summarizes the p-chem property values preliminarily selected
for use in the risk evaluation from among the range of reported values collected as of March
2020. This table differs from that presented in the Proposed Designation of o-Dichlorobenzene
(CASRN 95-sii- m is a High-Priority Substance for Risk Evaluation (U.S. EPA, 2019a) and may
be updated as EPA collects additional information through systematic review methods. All p-
chem property values that were extracted and evaluated as of March 2020 are presented in the
supplemental file Data Extraction and Data Evaluation Tables for Physical Chemical Property
Studies (EPA-HQ-OPPT-2018-0444).
Table Apx B-l. Physical and Chemical properties of o-Dichlorobenzene
Properly or Kndpoinl
Value51
Reference
Data
Quality
Ualing
Molecular formula
C6H4Cl2
NA
NA
Molecular weight
147.00 g/mol
NA
NA
Physical state
Liquid
Rumble, 2018
High
Physical properties
Pale yellow with
pleasant, aromatic
odor
RSC, 2019
High
Melting point
-17.03°C
O'Neil, 2013
High
Boiling point
180.2°C
Rumble, 2018
High
Density
1.3009 g/cm3 at 25°C
Baragi, 2005
High
Vapor pressure
1.36 mm Hg at 25 C
NLM, 2014
High
Vapor density
5.05 (air = 1)
NLM, 2014
High
Water solubility
156 rng/L at 25°C
NLM, 2014
High
Log Octanol/water
partition coefficient (Log
Kow)
3.43
NLM, 2014
High
Henry's Law constant
0.00192 atm-m Vmol
at 25°C
U.S. EPA, 2019
High
Flash point
66°C
O'Neil, 2013
Medium
70

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Auto flammability
Not available


Viscosity
1.324 cP at 25°C
Baragi, 2005
High
Refractive index
1.5499 at 25°C
Baragi, 2005
High
Dielectric constant
10.36
Elsevier, 2019
High
a Measured unless otherwise noted.
NA = Not applicable
71

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Appendix C ENVIRONMENTAL FATE AND TRANSPORT
PROPERTIES OF 0-DICHLOROBENZENE
Table Apx C-l provides the environmental fate characteristics that EPA identified and
considered in developing the scope for o-dichlorobenzene.
Table Apx C-l. Environmental Fate and Transport Properties of o-Dichlorobenzene
Properly or
Knilpoint
\ 'si Inc..
Reference
Direct
Photodegradati on
Not expected; does not contain chromophores
that absorb at wavelengths >290 nm
HSDB (2014) citing Lvman
et al. (1990); OECD (2001)
Indirect
Photodegradati on
ti/2 = 38 days (12-hour day; 5 x 105 -OH/cm3)
from OH rate constant 4.2 x 10-13
cm3/molecule-second at 25 °Cb
HSDB C citing
Atkinson (1989); Physprat)
Q

ti/2 = 27 days (5 x 105 -OH/cm3); -OH rate
constant 3 x 10"13 cm3/molecule-second
OECD (2001)

ti/2 = 53 days (1 x 105 -OH/cm3); -OH rate
constant 3 x 10"13 cm3/molecule-second
OECDX200U
Hydrolysis
Stable; o-dichlorobenzene is not expected to
undergo
hydrolysis in the environment due to the
lack of hydrolysable functional groups
HSDB t citing
Lyman et al. (1990)
Biodegradation
0% of theoretical BOD/28 days (Japanese
MITI test) with activated sludge (aerobic
water)
HSDB C citing
CIII (1992)

25%/300 days removed from an
aerobic soil column (closed system)
(aerobic soil)
OECD (2001)

100%/4 months in aerobic Rhine River
sediment column (closed system) after 60-
100-day lag period (aerobic sediment)
AT SDR (2006)

ti/2 = 37 days (first-order biodegradation
rate constant = 0.0188 days"1) in acclimated
anaerobic sediment slurry obtained from the
Tsurumi River, Japan (anaerobic sediment)
HSDB C citing
Masunaga et al. (1996)

6.3%/10 weeks in an alkaline soil sample
HSDB C citing Haider
et al. (1974)

ti/2 = 117 days in a heterogeneous aquifer at
the Columbus Air Force Base, Mississippi
HSDB C citing
Stauffer et al. (1994)

ti/2 = 12 days in pure culture laboratory batch
microcosms following a 13-day lag period
HSDB C citing
Nielsen et al. (1996)
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Wastewater
Treatment
Elimination efficiencies from 15% to 53%
during infiltration and soil percolation of o-
dichlorobenzene containing wastewater
from a wastewater treatment plant
OECD (2.001)
75%) total removal (47%> by biodegradation,
7%> by sludge, 20% by volatilization to air;
estimated)13
EPI Suit
2012b")
Bioconcentration
Factor
90-260 (carp) and 270-560 (rainbow trout)
H.SDB C citing CITI
(1992) and Oliver and
Niimi (1983)
6,212-19,700 (Selenastrum capricornutum,
algae)
H.SDB C citing
Casserly et al. (1983);
OECD (2.001)
66 (whole-body BCF measured in bluegill
sunfish)
H.SDB (2014) citing
Barrows et al. (1980)
Bioaccumulation
Factor
240 (estimated)13
EPI Suit
2012b)
Soil Organic
Carbon:Water
2.45 (in silt loam soil)
H.SDB (2014) citing Chiou
et al. (1979)
a Measured unless otherwise noted
bEPI Suite™ physical property inputs: Log Kow = 3.43, BP = 180 °C, MP = -16.7 °C, VP = 1.36 mm Hg,
WS = 156 mg/L, HLC = 0.00192 atm-m3/mole, BIOP = 40, BioA = 10 and BioS = 10 SMILES:
c(c(cccl)Cl)(cl)Cl
Notes: -OH = hydroxyl radical; OECD = Organisation for Economic Cooperation and Development; TG
= test guideline; GC = gas chromatography; MITI = Ministry of International Trade and Industry; BCF =
bioaccumulation factor; BOD = biochemical oxygen demand
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Appendix D REGULATORY HISTORY
The chemical substance, o-dichlorobenzene, is subject to federal and state laws and regulations
in the United States Table_Apx D-l and Table D-2. Regulatory actions by other governments,
tribes and international agreements applicable to o-dichlorobenzene are listed in Table Apx. D-3.
D.l Federal Laws and Regulations
Table Apx D-l. Federal Laws and Regulations
Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
EPA Regulations
Toxic Substances
Control Act (TSCA) -
Section 6(b)
EPA is directed to identify high-priority
chemical substances for risk evaluation;
and conduct risk evaluations on at least
20 high priority substances no later than
three and one-half years after the date of
enactment of the Frank R. Lautenberg
Chemical Safety for the 21st Century
Act.
o-Dichlorobenzene is one of
the 20 chemicals EPA
designated as a High-Priority
Substance for risk evaluation
under TSCA (8
December 30, 2019).
Designation of o-
dichlorobenzene as high-
priority substance constitutes
the initiation of the risk
evaluation on the chemical.
Toxic Substances
Control Act (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
o-Di chl orob enzene
manufacturing (including
importing), processing and
use information is reported
under the CDR rule (76 FR
50816, August 16, 2011).
Toxic Substances
Control Act (TSCA) -
Section 8(b)
EPA must compile, keep current and
publish a list (the TSCA Inventory) of
each chemical substance manufactured
(including imported) or processed in the
United States.
o-Di chl orobenzene was on the
initial TSCA Inventory and
therefore was not subject to
EPA's new chemicals review
process under TSCA section 5
( 09, March 29,
1995).
Toxic Substances
Control Act (TSCA) -
Section 4
Provides EPA with authority to issue
rules, enforceable consent agreements
and orders requiring manufacturers
Four chemical data
submissions from test rules
were received for o-
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Msiliilcs/Ucgiihilions
Description of Aiilhorhy/Ucgiihilion
Description of Ucgiihilion

(including importers) and processors to
test chemical substances and mixtures.
dichlorobenzene including
two water studies (persistence
and stability), one
mutagenicity/genetic toxicity
study (1983), and one
reproductive toxicity study
(1989) (U.S. EPA ChemView.
Accessed April 15, 2019).
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. A
facility that meets reporting requirements
must submit a reporting form for each
chemical for which it triggered reporting,
providing data across a variety of
categories, including activities and uses
of the chemical, releases and other waste
management (e.g., quantities recycled,
treated, combusted) and pollution
prevention activities (under section 6607
of the Pollution Prevention Act). These
data include on- and off-site data as well
as multimedia data (i.e., air, land and
water).
o-Dichlorobenzene is a listed
substance subject to reporting
requirements under 40 CFR
372.65 effective as of January
01, 1987.
Federal Insecticide,
Fungicide, and
Rodenticide Act
(FIFRA) - Sections 3
and 6
FIFRA governs the sale, distribution and
use of pesticides. Section 3 of FIFRA
generally requires that pesticide products
be registered by EPA prior to
distribution or sale. Pesticides may only
be registered if, among other things, they
do not cause "unreasonable adverse
effects on the environment." Section 6 of
FIFRA provides EPA with the authority
to cancel pesticide registrations if either
(1) the pesticide, labeling, or other
material does not comply with FIFRA;
or (2) when used in accordance with
widespread and commonly recognized
o-Dichlorobenzene was
registered as an antimicrobial
and conventional chemical on
June 3, 1983. No registration
actions have been submitted
in support of o-
dichlorobenzene, for either
antimicrobial and
conventional chemical uses.
No reregistration activities
have been conducted. The last
products containing o-
dichlorobenzene were
cancelled in November 1992.
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Msiliilcs/Ucgiihilions
Description of Aiithorhy/Ucgiihilion
Description ol' Ucgnhilion

practice, the pesticide generally causes
unreasonable adverse effects on the
environment.

Clean Air Act (CAA) -
Section 111(b)
Requires EPA to establish new source
performance standards (NSPS) for any
category of new or modified stationary
sources that EPA determines causes, or
contributes significantly to, air pollution,
which may reasonably be anticipated to
endanger public health or welfare. The
standards are based on the degree of
emission limitation achievable through
the application of the best system of
emission reduction (BSER) which
(taking into account the cost of achieving
reductions and environmental impacts
and energy requirements) EPA
determines has been adequately
demonstrated.
o-Dichlorobenzene is subject
to the NSPS for equipment
leaks of volatile organic
compounds (VOCs) in the
synthetic organic chemicals
manufacturing industry for
which construction,
reconstruction or modification
began after January 5, 1981
and on or before November 7,
2006 (40 CFR Part 60,
Subpart VV).
Clean Water Act
(CWA) Section
304(a)(1)
Requires EPA to develop and publish
ambient water quality criteria (AWQC)
reflecting the latest scientific knowledge
on the effects on human health that may
be expected from the presence of
pollutants in any body of water.
In 2015 EPA published
updated AWQC for o-
dichlorobenzene, including a
recommendation of 1,000
(|ig/L) for "Human Health for
the consumption of Water +
Organism" and 3,000 (|ig/L)
for "Human Health for the
consumption of Organism
Only" for states and
authorized tribes to consider
when adopting criteria into
their water quality standards.
Clean Water Act
(CWA) - Section
301(b), 304(b), 306,
207(a) and 307(b)
Clean Water Act Section 307(a)
establishes a list of toxic pollutants or
combination of pollutants under the
CWA. The statue specifies a list of
families of toxic pollutants also listed in
the Code of Federal Regulations at 40
CFR Part 401.15. The "priority
pollutants" specified by those families
are listed in 40 CFR Part 423 Appendix
o-Dichlorobenzene is
designated as a toxic pollutant
under section 307(a)(1) of the
CWA and as such is subject to
effluent limitations. (40 CFR
401.15). o-Dichlorobenzene is
designated as a priority
pollutant as well (40 CFR Part
423 Appendix A Under CWA
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Msiliilcs/Ucgiihilions
Description of Aiithorhy/Ucgiihilion
Description ol' Ucgnhilion

A. These are pollutants for which best
available technology effluent limitations
must be established on either a national
basis through rules (Sections 301(b),
304(b), 307(b), 306) or on a case-by-case
best professional judgement basis in
NPDES permits, see Section
402(a)(1)(B). EPA identifies the best
available technology that is economically
achievable for that industry after
considering statutorily prescribed factors
and sets regulatory requirements based
on the performance of that technology.
section 304, o-
dichlorobenzene is included in
the list of total toxic organics
(TTO) (40 CFR 413.02(i)).
Clean Water Act
(CWA) - Section
311(b) (2)(A) and
501(a) of the Federal
Water Pollution
Control Act.
Requires EPA to develop, promulgate,
and revise as may be appropriate,
regulations designating as hazardous
substances, other than oil, which, when
discharged present an imminent and
substantial danger to the public health or
welfare, including, but not limited to,
fish, shellfish, wildlife, shorelines, and
beaches.
o-Dichlorobenzene is a
designated hazardous
substance in accordance with
Section 311(b)(2)(A) of the
Federal Water Pollution
Control Act (43 FR 10474,
March 13, 1978).
Safe Drinking Water
Act (SDWA) - Section
1412
Requires EPA to publish non-
enforceable maximum contaminant level
goals (MCLGs) for contaminants which
1. may have an adverse effect on the
health of persons; 2. are known to occur
or there is a substantial likelihood that
the contaminant will occur in public
water systems with a frequency and at
levels of public health concern; and 3. in
the sole judgement of the Administrator,
regulation of the contaminant presents a
meaningful opportunity for health risk
reductions for persons served by public
water systems. When EPA publishes an
MCLG, EPA must also promulgate a
National Primary Drinking Water
Regulation (NPDWR) which includes
either an enforceable maximum
contaminant level (MCL), or a required
o-Dichlorobenzene is subject
to NPDWR under the SDWA
with a MCLG of 0.6 Public
Health Goal and an
enforceable MCL of 0.6
(mg/L)2 (Section 1412) (52
FR 25690 January 30, 1991).
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Msiliilcs/Ucgiihilions
Dcscriplion of Aiithorhy/Ucgiihilion
Description ol' Ucgiihilion

treatment technique. Public water
systems are required to comply with
NPDWRs.

Resource Conservation
and Recovery Act
(RCRA) - Section
3001
Directs EPA to develop and promulgate
criteria for identifying the
characteristics of hazardous waste, and
for listing hazardous waste, taking into
account toxicity, persistence, and
degradability in nature, potential for
accumulation in tissue and other related
factors such as flammability,
corrosiveness, and other hazardous
characteristics.
o-Dichlorobenzene is
included on the list of
hazardous wastes pursuant to
RCRA 3001. RCRA
Hazardous Waste Code U070
(40 CFR section 261.33)
Comprehensive
Environmental
Response,
Compensation and
Liability Act
(CERCLA) - Sections
102(a) and 103
Authorizes EPA to promulgate
regulations designating as hazardous
substances those substances which, when
released into the environment, may
present substantial danger to the public
health or welfare or the environment.
EPA must also promulgate regulations
establishing the quantity of any
hazardous substance the release of which
must be reported under Section 103.
Section 103 requires persons in charge of
vessels or facilities to report to the
National Response Center if they have
knowledge of a release of a hazardous
substance above the reportable quantity
threshold.
o-Dichlorobenzene is a
hazardous substance under
CERCLA. Releases of o-
dichlorobenzene in excess of
100 pounds must be reported
(40 CFR 302.4).
Superfund
Amendments and
Reauthorization Act
(SARA)-
Requires the Agency to revise the
hazardous ranking system and update the
National Priorities List of hazardous
waste sites, increases state and citizen
involvement in the superfund program
and provides new enforcement
authorities and settlement tools.
o-Dichlorobenzene is listed on
SARA, an amendment to
CERCLA and the CERCLA
Priority List of Hazardous
Substances. This list includes
substances most commonly
found at facilities on the
CERCLA National Priorities
List (NPL) that have been
deemed to pose the greatest
threat to public health.
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Statutes/Regulations
Description of Authority/Regulation
Description of Regulation
Other Federal Regulations
Occupational Safety
and Health Act
(OSHA)
Requires employers to provide their
workers with a place of employment free
from recognized hazards to safety and
health, such as exposure to toxic
chemicals, excessive noise levels,
mechanical dangers, heat or cold stress
or unsanitary conditions (29 U.S.C
section 651 et seq.).
Under the Act, OSHA can issue
occupational safety and health standards
including such provisions as Permissible
Exposure Limits (PELs), exposure
monitoring, engineering and
administrative control measures, and
respiratory protection.
OSHA issued occupational
safety and health standards for
o-dichlorobenzene that
included a PEL of (C)50 ppm
(ceiling limit) (29 CFR
1910.1000).
Federal Hazardous
Materials
Transportation Act
(HMTA)
Section 5103 of the Act directs the
Secretary of Transportation to:
•	Designate material (including an
explosive, radioactive material,
infectious substance, flammable or
combustible liquid, solid or gas,
toxic, oxidizing or corrosive
material, and compressed gas) as
hazardous when the Secretary
determines that transporting the
material in commerce may pose an
unreasonable risk to health and
safety or property.
•	Issue regulations for the safe
transportation, including security, of
hazardous material in intrastate,
interstate and foreign commerce.
o-Dichlorobenzene is listed as
a hazardous material with
regard to transportation and is
subject to regulations
prescribing requirements
applicable to the shipment and
transportation of listed
hazardous materials (70 FR
34381, June 14 2005).
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D.2 State Laws and Regulations
Table Apx D-2. State Laws and Regulations
Stale Actions
Descripl ion of Act ion
State Air
Regulations
Allowable Ambient Levels
New Hampshire set a 24 hr AAL at 536 mg/m3 and Annual AAL at
357 mg/m3 (Env-A 1400: Regulated Toxic Air Pollutants).
Rhode Island set a 1 hour AAL at 2000 mg/m3 and an Annual AAL at
300 mg/m3 (Air Pollution Regulation No. 22)
State Drinking
Water Standards
and Guidelines
Arizona set an MCL of 0.6 mg/L and an MCLG of 0.6 mg/L for o-
dichlorobenzene (14 Ariz. Admin. Register 2978, August 1, 2008).
California set an MCL of 0.6 mg/L and a PHG of 0.6 mg/L in 1997
(Cal Code Regs. Title 26, § 22-64444), Delaware (Del. Admin. Code
Title 16, § 4462). Connecticut set an MCL of 0.6 mg/L for o-
dichlorobenzene (Conn. Agencies Regs. § 19-13-B102). Delaware set
an MCL of 0.6 mg/L for o-dichlorobenzene. Florida set an MCL of
6000 mg/L for o-dichlorobenzene (Fla. Admin. Code R. Chap. 62-
550), Maine (10 144 Me. Code R. Chap. 231), Maine set an MCL of
0.6 mg/L for o-dichlorobenzene. Massachusetts set an MCL of 0.6
mg/L (310 Code Mass. Regs. § 22.00). Michigan set an MCL of 600
mg/L (Mich. Admin. Code r.299.44 and r.299.49, 2017). Minnesota set
an MCL of 600 mg/L(chronic) for o-dichlorobenzene (Minn R. Chap.
4720). New Jersey set an MCL for 600 mg/L for o-dichlorobenzene
(7:10 N.J Admin. Code § 5.2). Pennsylvania set an MCL of .6 mg/L
for o-dichlorobenzene (25 Pa. Code § 109.202). Rhode Island set an
MCL of 600 mg/L for o-dichlorobenzene (Rules and Regulations
Pertaining to Public Drinking Water R46-13-DWQ).
State PELs
California PEL of 25 ppm, 150 mg/M and 50 ppm (Cal Code Regs.
Title 8, § 5155)
Hawaii PEL: 50 ppm ceiling and 300 mg/M (Hawaii Administrative
Rules section 12-60-50).
State Right-to-
Know Acts
o-Dichlorobenzene is listed on the Massachusetts Substance List
Massachusetts (105 Code Mass. Regs. § 670.000 Appendix A). New
Jersey lists o-dichlorobenzene on their Right-to-Know list (N.J.A.C.
7:1G). Pennsylvania lists o-dichlorobenzene on their Right-to-Know
list with an Environmental Hazard notation (P.L. 734, No. 159 and 34
Pa. Code § 323).
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Stale Actions
Dcscripl ion of Act ion
Chemicals of High
Concern to
Children
Several states have adopted reporting laws for chemicals in children's
products containing o-dichlorobenzene including Maine (38 MRS A
Chapter 16-D).
Other
o-Dichlorobenzene is on the MA Toxic Use Reduction Act (TURA)
list of April 3, 2019 (301 CMR 41.00).
D.3 International Laws and Regulations
TableApx D-3. Regulatory Actions by other Governments, Tribes, and International
Agreements	
Country/
Organization
Requirements and Restrictions
Canada
o-Dichlorobenzene is on the Domestic Substances List (Government
of Canada. Managing substances in the environment. Substances
Search. Database accessed April 17, 2019). Other regulations
include:
• Canada's National Pollutant Release Inventory (NPRI)
European Union
o-Dichlorobenzene was evaluated under the 2013 Community
rolling action plan (CoRAP) under regulation (European
Commission [EC]) Nol907/2006 - REACH (Registration,
Evaluation, Authorisation and Restriction of Chemicals) (ECHA
database. Accessed April 16, 2019).
Australia
o-Dichlorobenzene is subject to secondary notifications when
importing or manufacturing the chemical in Australia.
In 2001, o-dichlorobenzene was assessed. (o-Dichlorobenzene.
Priority Existing Chemical No. 14. Full Public Report (2001)).
Japan
o-Dichlorobenzene is regulated in Japan under the following
legislation:
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Country/
()r
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Appendix E PROCESS, RELEASE AND OCCUPATIONAL
EXPOSURE INFORMATION
This appendix provides information and data found in preliminary data gathering for o-
dichlorobenzene.
E.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.
E.l.l	Manufacture (Including Import)
In the 2016 CDR, three facilities submitted for o-dichlorobenzene. One facility identified itself
as an importer and the other two facilities claimed their manufacture or import status as
confidential business information (CBI). However, one of the two facilities with CBI claims is an
office building; therefore, this facility is likely an importer of record and is not a manufacturer.
The other facility with a CBI claim reported releases of o-dichlorobenzene to TRI for the 2015
reporting year (the same year for which data were reported for the 2016 CDR). However, in its
Form R, this facility reported that it neither produces nor imports the o-dichlorobenzene,
although it does use o-dichlorobenzene as a reactant and as a chemical processing aid. This
facility reported in this same manner on their Form R for reporting year 2018 (U.S. EPA, 2018b).
Therefore, EPA has not confirmed at this time if o-dichlorobenzene is manufactured in the
United States or if it is only imported into the United States.
E.l.1.1 Manufacture
Chlorinated benzenes are produced by the liquid-phase chlorination of benzene using a catalyst.
This reaction produces multiple chlorinated benzenes with hydrogen chloride as a byproduct.
The chlorinated benzenes include monochlorobenzene, dichlorobenzenes, trichlorobenzenes, and
substitutions up through the fully substituted hexachlorobenzene. The desired degree of chlorine
substitution can be controlled by the extent of reaction. The selectivity of the dichlorobenzene
structural isomers can be influenced by the choice of catalyst. Ferric chloride, the most common
catalyst, produces a /^-dichlorobenzene to o-dichlorobenzene molar ratio of 1.4-to-l. Higher
ratios can be achieved with different catalysts. Generally, meta-dichlorobenzene (1,3-
dichlorobenzene) is produced in small quantities, and 1,3,5-trichlorobenzene and 1,2,3,5-
tetrachlorobenzene are produced at approximately non-detectable levels (Kirk-Othmer, 2001).
Separation of the produced chlorinated benzenes is accomplished through a combination of
distillation and crystallization. Ortho- and pc/ra-dichlorobenzenes have similar vapor pressures
but different melt temperatures; therefore, they are separated using crystallization. Any unwanted
chlorinated benzene isomers may be incinerated on site or dechlorinated using hydrogen and a
catalyst to produce benzene and hydrogen chloride (Kirk-Othmer, 2001).
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E.l.1.2 Import
In general, chemicals may be imported into the United States in bulk via water, air, land, and
intermodal shipments (Tomer and Kane, 2015). These shipments take the form of oceangoing
chemical tankers, railcars, tank trucks, and intermodal tank containers. o-Dichlorobenzene is a
liquid at room temperature and is shipped in bulk in aluminum tank trucks and steel or stainless-
steel tank cars (Kirk-Othmer, 2001). Both imported and domestically manufactured commodity
chemicals may be repackaged by wholesalers for resale; for example, repackaging bulk
packaging into drums or bottles. The type and size of container will vary depending on customer
requirement. In some cases, QC samples may be taken at import and repackaging sites for
analyses. Some import facilities may only serve as storage and distribution locations, and
repackaging/sampling may not occur at all import facilities.
E.2 Processing and Distribution
E.2.1 Processing as a Reactant or Intermediate
Processing as a reactant or intermediate is the use of o-dichlorobenzene as a feedstock in the
production of another chemical via a chemical reaction in which o-dichlorobenzene is consumed
to form the product. In the 2016 CDR, one company reported use of o-dichlorobenzene as an
intermediate in the manufacture and preparation of chemical products (U.S. EPA, 2019b). o-
DCB is commonly reacted to form the chemical 3,4-dichloroaniline, which is used in the
production of several herbicides and for the production of 3,4,4'-trichlorocarbanilide (TCC), a
bacteriostat used in deodorant soaps (Kirk-Othmer, 2001).
Exact operations for the use of o-dichlorobenzene as a reactant to produce other chemicals are
not known at this time. For using a chemical as a reactant, operations would typically involve
unloading the chemical from transport containers and feeding the chemical into a reaction
vessel(s), where the chemical would react either fully or to a lesser extent. Following completion
of the reaction, the produced substance may be purified further, thus removing unreacted o-
dichlorobenzene (if any exists).
E.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. In the 2016 CDR,
companies reported use of o-dichlorobenzene as a pigment in the manufacturing of paint and
coating, printing ink, and synthetic dye and pigment, as well as a solvent in the manufacturing of
plastic material and resin (U.S. EPA, 2019b). The exact processes used to formulate products
containing o-dichlorobenzene are not known at this time; however, several ESDs published by
the OECD and Generic Scenarios published by EPA have been identified that provide general
process descriptions for these types of products.
The formulation of coatings and inks typically involves dispersion, milling, finishing and filling
into final packages (OECD, 2009a). In plastics and rubber manufacturing the formulation step
usually involves the compounding of the polymer resin with additives and other raw materials to
form a masterbatch in either open or closed blending processes (U.S. EPA, 2014; OECD,
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2009b). After compounding, the resin is fed to an extruder where is it converted into pellets,
sheets, films or pipes (U.S. EPA, 2014).
EPA plans to further investigate processing uses of o-dichlorobenzene during risk evaluation.
E.3 Uses
E.3.1 Ink, Toner, and Colorant Products
The 2016 CDR reports use of o-dichlorobenzene in ink, toner, and colorant products at
concentrations of less than 30% by weight. Public comment from the Aerospace Industries
Association (AIA) indicates o-dichlorobenzene is a constituent in inks (U.S. EPA, 2019b); EPA-
HQ-OPPT-2018-0444-0004). The AIA comment specifically states that o-dichlorobenzene's use
in inks includes its use as a precious metal ink that can be brushed onto a substrate. At this time,
it is unknown what the chemical's specific function is in the ink; EPA plans to further investigate
this use in the risk evaluation.
E.3.2 Coatings and paints, thinners, paint removers
The 2016 CDR reports use of o-dichlorobenzene in paints and coatings at concentrations of less
than 30% by weight (U.S. EPA, 2019b). A public comment from the Aerospace Industries
Association (AIA) also indicates o-dichlorobenzene is used as a constituent in paint strippers, but
does not provide information on the specific function the chemical serves (EPA-HQ-OPPT-
2018-0444-0004). EPA plans to further investigate the specific coatings and paints, thinners, and
paint removers use activities of o-dichlorobenzene during the risk evaluation.
E.3.3 Lubricants and oils
The AIA submitted public comments indicating that o-dichlorobenzene is a constituent in oils
used in the aerospace industry. These oils include automotive engine oils for vehicle or
equipment engine maintenance and oils used to maintain tools (EPA-HO-OPPT-2Q18-0444-
0004). The Motor and Equipment Manufacturers Association (MEMA) and the Alliance of
Automobile Manufacturers (the Alliance) also submitted a public comment stating that various
members of the Alliance identified using o-dichlorobenzene in the production of various
automobile parts and as a lubricant (EPA-HQ-OPPT-2019-0131 -0022).
The Consumer Product Information Database (CPID, 2020) identifies one fuel additive product
that contains this chemical. A fuel additive from Marvel Oil Company (2017) was found to
contain 0.1 to 1 wt% o-dichlorobenzene, as per its safety data sheet (SDS) (Marvel Mystery Oil,
2017). Marvel Mystery Oil is sold in small containers and can be added directly to the fuel tank
or the crankcase of engines for automobiles, trucks, agricultural and earth moving equipment,
marine vehicles, recreational vehicles, small powered landscaping equipment (such as
chainsaws, lawn mowers, and snow blowers), and gasoline-powered generators. Marvel Mystery
Oil improves oil lubrication and sludge control, improves fuel combustion, and aids engine
cleaning (Marvel Mystery Oil. 2017).
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E.3.4 Air Care Products
EPA identified various sources describing o-dichlorobenzene's use in air care products.
GoodGuide's (2011) Pollution Scorecard identifies use of this chemical in non-personal, non-
aerosol deodorants and air fresheners. NLM (2008) identifies use of o-dichlorobenzene as a
garbage and sewage deodorizer, and Kirk-Othmer (2001) identifies use of o-dichlorobenzene in
garbage treatment in Japan.
An SDS for deodorizing moth balls produced by Willert Home Products, Inc. shows that the
product contains o-dichlorobenzene in concentrations between 0.1 - 1% by weight (Willert,
2017). CPID and an SDS identify use of o-dichlorobenzene in a toilet bowl deodorizer also in
concentrations between 0.1- 1% by weight (CPID, 2020; Home Depot, 2019). The toilet bowl
deodorizer is designed to be attached with a hanger to the interior of the toilet bowl, where it
continuously deodorizes (Home Depot, 2019).
E.3.5 Other uses
EPA has identified additional uses of o-dichlorobenzene in various other TSCA-covered
conditions of use, such as its use in laboratory chemicals (Harrell Industries, 2015). A sheep-
branding fluid was found to contain 10 - 30% o-dichlorobenzene, per its SDS (Heiniger (2016)).
The Substances Prepared in Nordic Countries (SPIN) database identifies use of o-
dichlorobenzene in cleaning and washing agents in 2000 and the OECD identifies use of the
chemical as a cleaning and washing agent (SPIN,2019; OECD,2001).Other uses of o-
dichlorobenzene that were identified were its use in thinners used to clean brushes and tools used
with overglazes, and its use in some ceramics glazes (Johnson Matthet, Inc., 2017; Duncan OA
901 Essence (2014); Duncan OG 803 Mother of Pearl (2015)). EPA plans to further investigate
these other use activities of o-dichlorobenzene during the risk evaluation.
E.4 Disposal
Each of the conditions of use of o-dichlorobenzene may generate waste streams of the chemical
that are collected and transported to third-party sites for disposal, treatment, or recycling.
Industrial sites that treat or dispose onsite wastes that they themselves generate are assessed in
each condition of use assessment. Similarly, point source discharges of o-dichlorobenzene to
surface water are assessed in each condition of use assessment (point source discharges are
exempt as solid wastes under RCRA). Wastes of o-dichlorobenzene that are generated during a
condition of use and sent to a third-party site for treatment, disposal, or recycling may include
the following:
•	Wastewater: o-dichlorobenzene may be contained in wastewater discharged to POTW or
other, non-public treatment works for treatment. Industrial wastewater containing o-
dichlorobenzene discharged to a POTW may be subject to EPA or authorized NPDES
state pretreatment programs. The assessment of wastewater discharges to POTWs and
non-public treatment works of o-dichlorobenzene is included in each of the condition of
use assessments.
•	Solid Wastes: Solid wastes are defined under RCRA as any material that is discarded by
being: abandoned; inherently waste-like; a discarded military munition; or recycled in
86

-------
certain ways (certain instances of the generation and legitimate reclamation of secondary
materials are exempted as solid wastes under RCRA). Solid wastes may subsequently
meet RCRA's definition of hazardous waste by either being listed as a waste at 40 CFR
§§ 261.30 to 261.35 or by meeting waste-like characteristics as defined at 40 CFR §§
261.20 to 261.24. Solid wastes that are hazardous wastes are regulated under the more
stringent requirements of Subtitle C of RCRA, whereas non-hazardous solid wastes are
regulated under the less stringent requirements of Subtitle D of RCRA.
o-Dichlorobenzene is a U-listed hazardous waste under code U070 under RCRA;
therefore, discarded, unused pure and commercial grades of o-dichlorobenzene are
regulated as a hazardous waste under RCRA (40 CFR § 261.33(f)). Additionally, o-
dichlorobenzene is included in the non-specific source waste code F002 for spent
halogenated solvents. Therefore, spent halogenated solvent streams that contain o-
dichlorobenzene may be regulated as a hazardous waste under RCRA (40 CFR 8
261.31(a)).
• Wastes Exempted as Solid Wastes under RCRA: Certain conditions of use of o-
dichlorobenzene may generate wastes of o-dichlorobenzene that are exempted as solid
wastes under 40 CFR § 261.4(a). For example, the generation and legitimate reclamation
of hazardous secondary materials of o-dichlorobenzene may be exempt as a solid waste.
For the 2018 reporting year of the TRI program, 17 facilities reported in total over 55.3 million
pounds of o/7/?o-dichlorobenzene waste for 2018. Nearly all (97%) of the or//?o-dichlorobenzene
managed as waste during 2018 was managed on site by recycling. Waste treatment quantities
(nearly 1.6 million pounds) accounted for 2.8% of the total. Contributions from quantities burned
for energy recovery or released to the environment were very small, amounting to only 0.5% and
O.P/o, respectively, of the total quantity of ortho-dichlorobenzene managed as waste. Overall,
99.2% of the ortho-dichlorobenzene production-related waste was managed as such on site.
E.5 Preliminary Occupational Exposure Data
EPA presents below an example of occupational exposure-related information obtained from
preliminary data gathering. EPA plans to consider this information and data in combination with
other data and methods for use in the risk evaluation.
Table Apx E-l summarizes NIOSH Health Hazard Evaluations identified during EPA's
preliminary data gathering. The OSHA CEHD did not contain any monitoring data for o-
dichlorobenzene between the years 2010 and 2019.
Table Apx E-l. Summary of NIOSH HHEs with Monitoring for o-Dichlorobenzene a
Year i)l"
PuMicalion
Report Number
1 acilily Description
1981
HETA 81-065-938
Vehicle maintenance facility (METRO Bus Maintenance
Shop, Washington, D.C.)
87

-------
1980
HHE 77-99-726
Chemical manufacturer (DuPont Chambers Works,
Deepwater, New Jersey)
1976
74-107-279
Silicone manufacturer (General Electric Company, Silicone
Products Department, Waterford, New York)
a Table incluc
es HHEs identified to date.
88

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Appendix F SUPPORTING INFORMATION - Conceptual Model for Industrial and
Commercial Activities and Uses:
Table Apx F-l. Worker and Occupational Non-User Exposure Conceptual Model Supporting Table
l.ili ( \ili-
Shim-


Ri'k'iisi' /
r.\|>iisinv
Sii-ii.irin
l!\|)osuiv
P:i 1 hw :i\
I".\|)IISIIIV
Rimk-
Kcivpliir /
Piipuhiliiiii
I'hilis In
l!\;illl;ik-
K.iliiin.ik-
Manufacture
Domestic
CBI
Manufacture of
o-DCB
Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during
manufacturing, as o-DCB
Solid
Contact
1 )ermal
Workers
No
The potential for
exposures to workers is
not expected as o-DCB is
manufactured as liquid.
Vapor
Inhalation
Workers,
Occupational
Non-Users
(ONUs)
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.
Misl
Inhalation
Workers.
ON IJ
No
Misl generation is not
expected during
manufacturing.
Dust
Inhalation/( )ral
Workers.
ONI J
No
Dust generation is not
expected as o-DCB is
manufactured as liquid.
Liquid/Solid
Contact
Dennal
ONU
No
1 ¦ xposure is expected to
be primarily restricted to
workers who are directly
involved in working with
the chemical. ()NUs are
not expected to come in
direct contact with the
chemicals.
Import
Import
Repackaging of
Import
Containers
Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during import, but
exposure will only occur
89

-------
UIiCmIi-
Shim-
C:iU-»iir\
Sul)i;ili-»iir\
Ri'k'iisi' /
Sii-n;iriii
l!\|)iisuiv
P;i 1 hw :i\
I!\|)iisiiiv
Kouk-
Ri'ivpliir /
Piipuhiliiiii
I'hilis In
K\;illl;iU-
K.iliiin.ik-








in the event the imported
material is repackaged.




Solid
Contact
1 )ermal
Workers
No
The potential lor
exposures to workers
does not exist during
import, as o-DCB exists
as a liquid at room
temperature.




Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.




Mist
Inhalation
Workers.
ONU
No
Mist generation is not
expected during import or
repackaging.




Dust
Inhalation/Oral
Workers.
ONU
No
Dust generation is not
expected during import or
repackaging.




Liquid/Solid
Contact
1 )ermal
ONU
No
I ¦ xposures is expected to
be primarily restricted to
w orkers who are directly
involved in working with
the chemical. ONUs are
not expected to come in
direct contact with the
chemicals.


Reactants in All other
chemical product and
preparation
manufacturing

Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during processing
of o-DCB in liquid form.
Processing
As a Reactant
Reactants
Solid
Contact
Dermal
Workers
No
The potential for worker
exposures to solids is not
expected during
processing as o-DCB is
in liquid form.
90

-------
UIiCmIi-
C:iU-»iir\

Ri'k'iisi' /
Sii-n;iriii
l!\|)iisuiv
P;i 1 hw :i\
I!\|)iisiiiv
Kouk-
Ri-u-plnr /
Piipuhiliiiii
I'hilis In
K\;illl;iU-
K.iliiin.ik-




Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.
Mist
Inhalation
Workers.
ONU
No
Mist generation is not
expected during
processing as a reactant.
Dust
InhalationA )ral
Workers.
ONU
No
Dust generation is not
expected during
processiim as a reactant.
Liquid/Solid
Contact
1 )ennal
ONU
No
I -Ixposures is expected to
be primarily restricted to
workers who are directly
involved in working with
the chemical. ()NUs are
not expected to come in
direct contact with the
chemicals.
Incorporated
into
formulation,
mixture, or
reaction product
Intermediates in All
other chemical
product and
preparation
manufacturing
Intermediates
Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during processing
(incorporation into
formulation, mixture, or
reaction product), as o-
DCB is in liquid form.
Solid
Contact
1 )ermal
Workers
No
The potential for worker
exposures to solids is not
expected during
processing (incorporation
into formulation, mixture,
or reaction product), as o-
DC1J is in liquid form.
Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.
91

-------
l.ili-C \ili-
C:iU-»iir\
Sul)i;ili-»iir\
Ri'k'iisi' /
l!\|)iisuiv
I!\|)iisiiiv
Ri'ivpliir /
I'hilis In
K.iliiin.ik-


Kouk-
Piipuhiliiiii
ll\ ;illl;iU'




Mist
Inhalalion
Workers.
ONIJ
No
Mist generation is not
expected during
processing (incorporation
into formulation, mixture,
or reaction product).




Dust
Inhalation/Oral
Workers.
ONIJ
No
Dust generation is not
expected during
processing (incorporation
into formulation, mixture,
or reaction product).








I Aposures is expected to
be primarily restricted to
w orkers who are directly




Liquid/Solid
Contact
] )ennal
ONIJ
No
involved in working with
the chemical. ()NlJs are
not expected to come in
direct contact with the
chemicals.




Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during processing
(incorporation into
formulation, mixture, or


Solvents (which
become part of





reaction product), as o-
DCB is in liquid form.


product formulation
or mixture) in Plastic
material and resin
manufacturing;
synthetic rubber
Incorporated in
solvents in
product
formulation
Solid
Contact
Dermal
Workers
Yes
o-DCB may be
incorporated into a solid
or powder; therefore,
exposures to solids for
workers are possible.


manufacturing

Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.
92

-------
l.ili-C \ili-
C:iU-»iir\
Sul)i;ili-»iir\
Ri'k'iisi' /
l!\|)iisuiv
I!\|)iisiiiv
Ri'ivpliir /
I'hilis In
K.iliiin.ik-

P;i 1 hw :i\
Kouk-
Piipuhiliiiii
K\;illl;iU-




Dust
Inhalation/Oral
Workers,
ONU
Yes
o o-DCB may be
incorporated into a solid
or powder; therefore,







exposures to solids for
workers are possible.




Mist
Inhalation
Workers.
ONU
No
Mist generation is not
expected during







processing.








1 ¦ xposiires is expected to
be primarily restricted to








workers who are directly




Liquid/Solid
Contact
Dermal
ONU
No
involved in working with
the chemical. ONUs are
not expected to come in
direct contact with the
chemicals.




Liquid/Solid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during processing,
as o-DCB is in liquid
form; o-DCB may be


Pigments in: Printing
ink manufacturing;
Paint and coating
manufacturing;
Synthetic dye and
pigment




incorporated into a solid
or powder; therefore,
exposures to solids for
workers are possible.


Incorporated in
pigments in
product
formulations
Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.






Workers.
ONU

Mist aeneralion is not




Mist
Inhalation
No
expected during
processing.




Dust
Inhalation/Oral
Workers,
ONU
Yes
o-DCB may be
incorporated into a solid
or powder; therefore,







exposures to solids for
workers are possible.
93

-------
UIiCmIi-
Shim-
C:iU-»iir\

Ri'k'iisi' /
l''\|>IIMIIV
Sii-n;iriii
l!\|)iisuiv
I!\|)iisiiiv
Kouk-
Ri'ivpliir /
Piipuhiliiiii
I'hilis In
ll\ ;illl;iU'
K.iliiin.ik-




Liquid/Solid
Contact
I )ermal
ONIJ
No
1 Ixposures is expected lo
be primarily restricted to
workers who are directly
involved in working with
the chemical. ()NI Is are
not expected to come in
direct contact with the
chemicals.
Commercial
Uses
Ink, toner, and
colorant
products
Ink and toners
Used in inks and
toners
Liquid/Solid
Contact
Dermal
Workers
Yes
Inks and loners are in
liquid/solid form;
therefore, exposures to
workers exists for o-DCB
used in inks and toners.
Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.
Mist/Dust
Inhalation/Oral
Workers,
ONU
Yes
Mist/dust generation is
possible during use of
inks and toners.
Liquid/Solid
Contact
Dermal
ONU
No
1 ¦ xposures is expected to
be primarily restricted to
workers who are directly
involved in working \\ ith
the chemical. ONUs are
not expected lo come in
direct contact with the
chemicals.
Paints and
coatings
Coatings and paints,
thinners, paint
removers
Used in paints
and coatings,
thinners, paint
removers
Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exist during use of paints
and coatings, thinners,
paint removers.
Solid
Contact
Dermal
Workers
No
1'he potential for worker
exposures to solid o-DCU
is not expected during
use of liquid paints and
94

-------
UIiCmIi-
C:iU-»iir\

Ri'k'iisi' /
Sii-n;iriii
l!\|)iisuiv
I!\|)iisiiiv
Koiik-
Ri-u-plnr /
Piipuhiliiiii
I'hilis In
K\;illl;iU-
K.iliiin.ili-








coatings, thinners, paint
removers.




Vapor
Inhalation
Workers,
ONU
Yes
There is potential lor
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.




Mist
Inhalation
Workers,
ONU
Yes
The potential of exposure
due to mist generation
exists during the
application of paints and
coatings, thinners, paint
removers.




Dusl
InhalalionA )ral
Workers.
ONU
No
Dust generation is not
expected during the use
of paints and coatings,
thinners, paint removers.




Liquid/Solid
Contact
I )ermal
ONU
No
1 -Ixposures is expected to
be primarily restricted to
workers who are directly
involved in working with
the chemical. ONUs are
not expected to come in
direct contact with the
chemicals.

Lubricants and
greases
Lubricants and
greases, degreasers
Use in lubricants
and greases,
degreasers
Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during use of o-
DCB in lubricants,
greases, and degreasers
as o-DCB is in liquid
form.



Solid
Contact
Dermal
Workers
No
The potential for worker
exposures to solid o-DCB
is not expected during
use in lubricants, greases.
95

-------
UIiCmIi-
C:iU-»iir\

Ri-k-iisi- /
Sii-n;iriii
l!\|)iisuiv
I!\|)iisiiiv
Rmik-
Ri-u-plnr /
Piipuhiliiiii
I'kilis In
K\;illl;iU-
R.iliiin.ik








or degreasers. as o-l)CB
is in liquid form.




Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.




Mist/1 )usl
Inhalation/Oral
Workers.
ONU
No
Mist generation is not
expected during its use as
in lubricants, greases, or
desreasers.




Liquid/Solid
Contact
] )ermal
ONU
No
I Aposures is expected to
be primarily restricted to
workers who are directly
involved in working with
the chemical. ONIJs are
not expected to come in
direct contact with the
chemicals.


Continuous action air
fresheners (including
toilet/ urinal
deodorizers
/fresheners)

Liquid/Solid
Contact
Dermal
Workers
Yes
Air care products can be
in solid or liquid form;
therefore, exposures to
workers exists for o-DCB
used in air care products.

Air care
products
Used in air care
products
Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.




Dust/Mist
Inhalation/Oral
Workers,
ONU
Yes
Dust/mist generation is
possible during use of air
care products.
96

-------
l.ili-C \ili-
(':ik-»iir\
Slll)i;ili-»nr\
Ri'k'iisi' /
l''\|>IIMIIV
l!\|)iisuiv
I!\|)iisiiiv
Ri'ivpliir /
Plans In
Kaliiinali-


Kouk-
Piipuhiliiiii
ll\ alliali'








1 Ixposures is expected to
be primarily restricted to








workers who are directly




Liquid/Solid
Contact
I )ermal
ONIJ
No
involved in working with
the chemical. ()NWs are
not expected to come in
direct contact with the
chemicals.




Liquid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers is
expected during use of o-
DCB as a laboratory
chemical, sheep-branding
fluid, or in furniture care
products as o-DCB is in
liquid form.








The potential for worker




Solid
Dermal
Workers
No
exposures to solid o-DCB
is not expected during
use as a laboratory



Used as
laboratory
chemicals'
sheep-branding
fluids, and
furniture care
products
Contact
chemical, sheep-branding
fluid, or in furniture care

Other use
Laboratory chemicals;
sheep branding fluid,




products as o-DCB is in
liquid form.

furniture care
products
Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room
temperature.




Mist
Inhalation
Workers,
ONU
Yes
Mist generation is
possible during use of
furniture care products if







the products are spray-
applied




Dust
Inhalation/Oral
Workers.
ONU
No
Dust generation is not
expected during its use as
a laboratory chemical.







sheep-branding lluid, or
in furniture care products.
97

-------
l.ili-C \ili-

Slll)i;ili-»nr\
Ri'k'iisi' /
Sii-n;iri"
l!\|)iisuiv
I!\|)iisuiv
Ri'ivpliir /
I'kilis In
K.iliiin.ik-
Shim-

Kmik-
Piipuhiliiiii
ll\: 1111:11 c-








1 ¦ xposures is expected lo
be primarily restricted to








workers who are directly




Liquid/Solid
Contact
] )ermal
ONIJ
No
invoked in working with
the chemical. ()NI Is are
not expected to come in
direct contact with the
chemicals.




Liquid/Solid
Contact
Dermal
Workers
Yes
The potential for
exposures to workers
exists during this use as







liquid/solid formulations
may be disposed




Vapor
Inhalation
Workers,
ONU
Yes
There is potential for
vapor generation based
on o-DCB's vapor
pressure (VP) (VP =1.36
mmHg) at room


Emissions to air, in
wastewater, liquid
wastes, and solid
wastes





temperature.
Disposal
Disposal
Worker handling
wastes
Mist
Inhalation
Workers.
ONU
No
Mist generation is not
expected during disposal
of liquid w astes.



Dust
Inhalation/Oral
Workers,
ONU
Yes
Dust generation is
possible during disposal







of solid wastes.








I xposures is expected to
be primarily restricted to
workers who are directly




Liquid/Solid
Contact
1 )ermal
ONU
No
involved in working with
the chemical. ()NLJs are
not expected to come in
direct contact with the
chemicals.
98

-------
Appendix G SUPPORTING INFORMATION - CONCEPTUAL MODEL FOR
CONSUMER ACTIVITIES AND USES
Table Apx G-l. Consumer Exposure Conce
jtual Model Supporting Table
l .ile ( >cle
Si;i»e
( iilejion
Siibc.ik'iion
Koloiisc from
sou I'd'
r.\|)(tsiirc
PiilliNin
Kouli'
Kcccplor
I'liins In
l'l\illllillO
K;iliuiiiik'
Consumer
Use
Lubricants and
greases
Lubricants and
greases, degreasers
Direct contact
through
application or
use of products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in using the chemical. Bystanders
are not expected to come in direct contact
with the chemical.



Long-term
emission/mass-
transfer through
application or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.



Direct contact
through
application or
use of products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
No
The product is not expected to be spray
applied; therefore, mist generation is not
expected.
Consumer
Use
Air care products
Continuous action
air fresheners
(including
toilet/urinal
deodorizers/
fresheners)
Direct contact
during
installation
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in installing the product. Bystanders
are not expected to come in direct contact
with the chemical.


Long-term
emission/mass-
transfer through
installation or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.



Direct contact
through
application or
use of products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
No
The product is not expected to be spray
applied; therefore, mist generation is not
expected.
99

-------
l .ile ( >cle
Si;i»c
CiiK'jion
Siil)c;Meiior\
Koloiisc from
sou I'd'
r.\|)(tsiirc
PiilliNin
KoiiU'
Km'plor
Pliins In
Kiilioiiiilo
Consumer
Use
Other use
Thinners (Products
for cleaning brushes
and tools used with
overglazes)
Direct contact
through
application or
use of products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in using the chemical. Bystanders
are not expected to come in direct contact
with the chemical.



Long-term
emission/mass-
transfer through
application or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.



Direct contact
through
application or
use of products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
No
The product is not expected to be spray
applied; therefore, mist generation is not
expected.
Consumer
Use
Other use
Ceramics glaze
Direct contact
through
application or
use of products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in using the chemical. Bystanders
are not expected to come in direct contact
with the chemical.



Long-term
emission/mass-
transfer through
application or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.



Direct contact
through
application or
use of products
Mist
Inhalation
and Oral
Consumers
and
Bystanders
No
The product is not expected to be spray
applied; therefore, mist generation is not
expected.
Consumer
Use
Other use
Sheep-branding
fluid
Direct contact
through
application or
use of products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in using the chemical. Bystanders
are not expected to come in direct contact
with the chemical.
100

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l .ile ( >cle
Si;i»c
CiiK'jion
Siil)c;Meiior\
Koloiisc from
sou I'd'
r.\|)(tsiirc
PiilliNin
KoiiU'
Km'plor
Pliins In
Kiilioiiiilo



Long-term
emission/mass-
transfer through
application or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.
Direct contact
through
application or
use of products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
No
The product is not expected to be spray
applied; therefore, mist generation is not
expected.
Consumer
Use
Other use
Cleaning and
furniture care
products
Direct contact
through
application or
use of products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in using the chemical. Bystanders
are not expected to come in direct contact
with the chemical.
Long-term
emission/mass-
transfer through
application or
use of products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.



Direct contact
through
application or
use of products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
Yes
The potential for exposure due to mist
generation exists during the application of
cleaning and furniture care products.



Direct contact
through handling
or disposal of
products
Liquid/
Solid
Contact
Dermal
Consumers
Yes
Exposure is expected to be primarily
restricted to consumers who are directly
involved in handling or disposing the
chemical. Bystanders are not expected to
come in direct contact with the chemical.
Consumer
Handling of
Disposal and
Waste
Wastewater,
Liquid wastes
and solid wastes
Wastewater, Liquid
wastes and solid
wastes
Long-term
emission/mass-
transfer through
handling or
disposal of
products
Vapor
Inhalation
Consumers
and
Bystanders
Yes
o-DCB is volatile at room temperature;
inhalation pathway should be further
analyzed.
101

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l .ile ( >cle
Si;i»c
CsiK'Sion
Siil)c;Meiior\
Koloiisc from
SOU ITO
l-'.\|)osuro
PiilliNin
KoiiU'
Km'plor
Pliins lo
Kiilioiiiilo



Direct contact
through handling
or disposal of
products
Mist
Inhalation
and
Dermal
Consumers
and
Bystanders
Yes
Mist generation is not expected during
handling or disposal.
102

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Appendix H SUPPORTING INFORMATION - CONCEPTUAL MODEL FOR
ENVIRONMENTAL RELEASES AND WASTES
TableApx H-l. Environmental Exposure Conceptual Model Supporting Table
l.il'c
( \clc
S(;i»e
Csili'Sion
Release
l'l\|)OMIIV
PiKhwin /
Medhi
l'l\|)OMIIV
Koii les
Reeeplor/
Population
I'lilllS (o
R;ilion;ile



Near facility
ambient air
concentrations
Inhalation
General
Population
Yes
o-Dichlorobenzene air and
deposition to nearby bodies of


Emissions to Air
Indirect
deposition to
Oral
Dermal
General
Population
Yes
water and soil are expected
exposure pathways.

Emissions

nearby bodies
of water and
soil catchments
TBD
Aquatic and
Terrestrial
Receptors
Yes

All
to Air
Hazardous and
Municipal Waste
Incinerator
Near facility
ambient air
concentrations/
Inhalation
General
Population

Stationary source releases of o-
dichlorobcnzcnc to ambient air
arc under the jurisdiction of


Indirect
deposition to
nearby bodies
of water and
soil catchments
TBD
Aquatic and
Terrestrial
Species
No
the RCRA and CAA


Industrial pre-
treatment and
wastewater
Direct release
into surface
water and
TBD
Aquatic and
Terrestrial
Receptors
Yes
EPA has developed Ambient
Water Quality Criteria for
8 The exposure pathways, exposure routes and hazards that EPA plans to evaluate are subject to change in the final scope, in light of comments received on this
draft scope and other reasonably available information. EPA continues to consider whether and how other EPA-administered statutes and any associated
regulatory programs address the presence of o-dichlorobenzene in exposure pathways falling under the jurisdiction of these EPA statutes.
103

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Life
< \ck
Sl;i»c
Csili'Siitn
Release
I'1\|)osiiiv
Pathway /
Media
I'lxposuiv
Routes
Km'plor/
Population
Plans to
l.\alua(es
Kiilioualo

W asicuatcr
Kl' Liquid
W'asies
treatment. ni"
P< >TW
nidi reel
pariiiiouum to
sedimeiii
()ral
Dermal
(icueral
Population
K|
proieeliou of hiimaii health for
"-diehloroheiizeiie



1 )i'iiikiim Water
\ la Surface or
(uound W'aler
Oral
Dermal and
Inhalation
(C u
shoucrium
(icueral
Population
K|
"Hie driukiim water exposure
palhwas for "-diehloroheiizeiie
is eurreiiilv addressed m the
SDW' \ rcmilalor> auaklical
process lor puhlie water
s\ sienis



1 Siosollds
application in
soil and or
migration to
groundwater
and/or surface
water
()ral ie u
iimcsiiou of
SOll 1
Inhalation
(leneral
Population
VI..
I ulikelv lo he a route lo
ueueral population since •>-
diehloroheiizeiie is uoi
expected to sorb onto
biosolids.



TBD
Aquatic and
Terrestrial
receptors
Yes



U nderground
injection
Migration to
groundwater,
potential
Oral
Dermal
Inhalation
General
Population
No
o-Dichlorobcnzcnc is released
to Class 1 Underground
Injection Wells which arc



surface/drinking
water

Aquatic and
Terrestrial
Species

covered by SDW A and RCRA.




TBD




Solid and
Hazardous.
Lcachalc to
soil, ground
Oral
Dermal
General
Population
No
o-Dichlorobenzene is included
on the list of hazardous w astes
pursuant to RCRA 3001 (40
Disposal
Liquid
Wastes
Municipal landfill
and other land
disposal
water and/or
mitigation to
surface water
TBD
Aquatic and
Terrestrial
Receptors

CFR §§ 261.33).
104

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