A EPA
EPA Document# EPA-740-D-20-004
April 2020
United States	Office of Chemical Safety and
Environmental Protection Agency	Pollution Prevention
Draft Scope of the Risk Evaluation for
1,1-Dichloroethane
CASRN 75-34-3
CH,
CI
April 2020

-------
TABLE OF CONTENTS
ACKNOWLEDGEMENTS	5
ABBREVIATIONS AND ACRONYMS	6
EXECUTIVE SUMMARY	9
1	INTRODUCTION	12
2	SCOPE OF THE EVALUATION	12
2.1	Reasonably Available Information	12
2.1.1	Search of Gray Literature for All Disciplines	13
2.1.2	Search of Literature from Publicly Available Databases (Peer-Reviewed Literature)	14
2.1.3	Search Results for TSCA Submissions	19
2.2	Conditions of Use	20
2.2.1	Categories and Subcategories of Conditions of Use Included in the Scope of the Risk
Evaluation	21
2.2.2	Activities Excluded from the Scope of the Risk Evaluation	21
2.2.3	Production Volume	22
2.2.4	Overview of Conditions of Use and Lifecycle Diagram	22
2.3	Exposures	24
2.3.1	Physical and Chemical Properties	24
2.3.2	Environmental Fate and Transport	24
2.3.3	Releases to the Environment	24
2.3.4	Environmental Exposures	26
2.3.5	Occupational Exposure	26
2.3.6	Consumer Exposure	27
2.3.7	General Population Exposures	27
2.4	Hazards (Effects)	27
2.4.1	Environmental Hazards	27
2.4.2	Human Health Hazards	28
2.5	Potentially Exposed or Susceptible Subpopulations	28
2.6	Conceptual Models	29
2.6.1	Conceptual Model for Industrial and Commercial Activities and Uses	29
2.6.2	Conceptual Model for Consumer Activities and Uses	31
2.6.3	Conceptual Model for Environmental Releases and Wastes: Potential Exposures and
Hazards (Regulatory Overlay)	31
2.6.3.1	Ambient Air Pathway	33
2.6.3.2	Drinking W ater Pathway	33
2.6.3.3	Ambient Water Pathway	34
2.6.3.4	Disposal and Soil Pathways	34
2.6.4	Conceptual Model for Environmental Releases and Wastes	35
2.7	Analysis Plan	37
2.7.1	Physical and Chemical Properties and Environmental Fate	37
2.7.2	Exposure	38
2.7.2.1	Environmental Releases	38
2.7.2.2	Environmental Exposures	40
2.7.2.3	Occupational Exposures	41
2

-------
2.7.2.4	Consumer Exposures	43
2.7.2.5	General Population	43
2.7.3	Hazards (Effects)	45
2.7.3.1	Environmental Hazards	45
2.7.3.2	Human Health Hazards	46
2.7.4	Summary of Risk Approaches for Characterization	48
2.8 Peer Review	49
REFERENCES	50
APPENDICES	54
Appendix A LIST OF GRAY LITERATURE SOURCES	54
Appendix B PHYSICAL AND CHEMICAL PROPERTIES OF 1,1 -DICHLOROETHANE	57
Appendix C ENVIRONMENTAL FATE AND TRANSPORT PROPERTIES OF 1,1-
DICHLOROETHANE	59
Appendix D REGULATORY HISTORY	60
D.l State Laws and Regulations										64
D.2	International Laws and Regulations......																	.........65
Appendix E PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE INFORMATION	66
E.l	Process Infonnation...													...............66
E. 1.1 Manufacture (Including Import)	66
E. 1.1.1 Manufacture	66
E.l. 1.2 Import	66
E. 1.2 Processing and Distribution	66
E. 1.2.1 Processing as a Reactant or Intermediate	66
E.l.2.2 Recycling	67
E.l.3 Uses	67
E.l.3.1 Laboratory Use	67
E.l.4 Disposal	67
E.2 Sources Containing Potentially Relevant Data or Infonnation					....68
Appendix F SUPPORTING INFORMATION - CONCEPTUAL MODEL FOR INDUSTRIAL AND
COMMERCIAL ACTIVITIES AND USES	69
Appendix G SUPPORTING INFORMATION - CONCEPTUAL MODEL FOR ENVIRONMENTAL
RELEASES AND WASTES	73
LIST OF TABLES
Table 2-1. Results of Title Screening of Submissions to EPA under Various Sections of TSCA	20
Table 2-2. Conditions of Use Included in the Scope of the Risk Evaluation	21
Table 2-3. Summary of 1,1-Dichloroethane TRI Production-Related Waste Managed in 2018	25
Table 2-4. Summary of Releases of 1,1-Dichloroethane to the Environment During 2018*	25
Table 2-5. Categories and Sources of Environmental Release Data	38
Table 2-6. Potential Sources of Occupational Exposure Data	42
3

-------
LIST OF FIGURES
Figure 2-1. Gray Literature Tags by Discipline for 1,1-Dichloroethane	13
Figure 2-2. Peer-Reviewed Literature - Physical-Chemical Properties Search Results for 1,1-
Dichloroethane	15
Figure 2-3. Peer-Reviewed Literature - Fate and Transport Search Results for 1,1-Dichloroethane	16
Figure 2-4. Peer-Reviewed Literature - Engineering Search Results for 1,1-Dichloroethane	17
Figure 2-5. Peer-Reviewed Literature - Exposure Search Results for 1,1-Dichloroethane	18
Figure 2-6. Peer-Reviewed Literature - Hazard Search Results for 1,1-Dichloroethane	19
Figure 2-7. 1,1-Dichloroethane Life Cycle Diagram	23
Figure 2-8. 1,1-Dichloroethane Occupational Exposure Conceptual Model for Industrial and
Commercial Activities and Uses: Worker and Occupational Non-User Exposures and
Hazards	30
Figure 2-9. 1,1-Dichloroethane Conceptual Model for Environmental Releases and Wastes:
Environmental Exposures and Hazards (Regulatory Overlay)	32
Figure 2-10. 1,1-Dichloroethane Conceptual Model for Environmental Releases and Wastes:
Environmental Exposures and Hazards	36
LIST OF APPENDIX TABLES
TableApx A-l. List of Gray Literature Sources for 1,1-Dichloroethane	54
TableApx B-l. Physical and Chemical Properties of 1,1-Dichloroethane	57
Table Apx C-l. Environmental Fate and Transport Properties of 1,1-Dichloroethane	59
Table_Apx D-l. Federal Laws and Regulations	60
Table_Apx D-2. State Laws and Regulations	64
Table Apx D-3. Regulatory Actions by other Governments, Tribes, and International Agreements	65
Table Apx E-l. Summary of Industry Sectors with 1,1-Dichloroethane Personal Monitoring Air
Samples Obtained from OSHA Inspections Conducted since 1984	 68
Table Apx E-2. Potentially Relevant Data Sources for Exposure Monitoring and Area Monitoring Data
from NIOSH Health Hazard Evaluations	68
Table Apx F-l. Worker and Occupational Non-User Exposure Conceptual Model Supporting Table.. 69
Table Apx G-l. General Population and Environmental Exposure Conceptual Model Supporting Table
	73
4

-------
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),
ERG (Contract No. EP-W-12-006), GDIT (Contract No. HHSN316201200013W), ICF (Contract
No.68HERC19D0003), SRC (Contract No. 68HERH19F0213), 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: J Q-QPPT-2018-042.6.
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.
5

-------
ABBREVIATIONS AND ACRONYMS
ACGIH
American Conference of Government Industrial Hygienists
ADME
Absorption, Distribution, Metabolism, and Excretion
AT SDR
Agency for Toxic Substances and Disease Registry
AWQC
Ambient Water Quality Criteria
BAF
Bioaccumulation Factor
BCF
Bioconcentration Factor
BMF
Biomagnification factor
BOD
Biochemical Oxygen Demand
BW34
Body Weight 3/4 Extrapolation
CAA
Clean Air Act
CalEPA
California Environmental Protection Agency
CASRN
Chemical Abstracts Service Registry Number
CBI
Confidential Business Information
CCL
Contaminant Candidate List
CDC
Centers for Diseases Control and Prevention
CDR
Chemical Data Reporting
CEHD
Chemical Exposure Health Data
CERCLA
Comprehensive Environmental Response, Compensation and Liability Act
CFR
Code of Federal Regulations
ChemSTEER
Chemical Screening Tool for Occupational Exposures and Releases
CHRIP
Chemical Risk Information Platform
COC
Concentration of Concern
CPCat
Chemical and Product Categories
CRC
Coordinating Research Council
CSCL
Chemical Substances Control Law
CWA
Clean Water Act
DMR
Discharge Monitoring Report
EC
Engineering Control(s)
ECHA
European Chemicals Agency
EPA
Environmental Protection Agency
EPCRA
Emergency Planning and Community Right-to-Know Act
ERG
Eastern Research Group
ESD
Emission Scenario Document
EU
European Union
FR
Federal Register
FYI
For your information
GACT
Generally Available Control Technology
GC
Gas Chromatography
GDIT
General Dynamics Information Technology
GESTIS
Substance Database contains information for the safe handling of hazardous substances

and other chemical substances at work
GS
Generic Scenario
HAP
Hazardous Air Pollutant
HERO
Health and Environmental Research Online
HHE
Health Hazard Evaluation

-------
HMTA
HPLC
HSDB
ICF
IECCU
IMAP
IRIS
ISHA
Koc
Kow
LCx
LOAELs
LOEC
MACT
MCL
MFG
MITI
MOA
MP
MWCs
NATA
NEI
NESHAP
NFPA
NHANES
NICNAS
NIOSH
NITE
NLM
NO A A
NOAELs
NOEC
NPDES
NPL
NTP
OCSPP
OELs
OECD
OEHHA
ONU
OPPT
OSHA
P-chem
PAC
PBPK
PBT
Federal Hazardous Materials Transportation Act
High Performance Liquid Chromatography
Hazardous Substances Data Bank
ICF is a global consulting services company
Indoor Environmental Concentrations in Buildings with Conditioned and Unconditioned
Zones
Inventory Multi-Tiered Assessment and Prioritisation (Australia)
Integrated Risk Information System
Industrial Safety and Health Act
Organic Carbon: Water Partition Coefficient
Octanol: Water Partition Coefficient
Lethal Concentration
Lowest Observed Adverse Effect Level
Lowest Observed Effect Concentration
Maximum Achievable Control Technology
Maximum Contaminant Level
Manufacturing
Ministry of International Trade and Industry
Mode of Action
Montreal Protocol
Municipal waste combustors
National-scale Air Toxics Assessment
National Emissions Inventory
National Emission Standards for Hazardous Air Pollutants
National Fire Protection Association
National Health and Nutrition Examination Survey
National Industrial Chemicals Notification and Assessment Scheme (Australia)
National Institute for Occupational Safety and Health
National Institute of Technology and Evaluation
National Library of Medicine
National Oceanic and Atmospheric Administration
No Observed Adverse Effect Level
No Observed Effect Concentration
National Pollutant Discharge Elimination System
National Priorities List
National Toxicology Program
Office of Chemical Safety and Pollution Prevention
Occupational Exposure Limits
Organisation for Economic Co-operation and Development
Office of Environmental Health Hazard Assessment (California)
Occupational Non-User
Office of Pollution Prevention and Toxics
Occupational Safety and Health Administration
Phy si cal -chemi cal
Protective Action Criteria
Physiologically Based Pharmacokinetic
Persistent, Bioaccumulative, and Toxic
7

-------
PECO
Population, Exposure, Comparator, Outcome
PEL
Permissible Exposure Limit
PESS
Potentially Exposed or Susceptible Subpopulations
PODs
Points of Departure
POTW
Publicly Owned Treatment Works
PPE
Personal Protective Equipment
PV
Production Volume
PWSs
Public Water Systems
RegDet
Regulatory Determinations
RCRA
Resource Conservation and Recovery Act
RDF
Refuse-derived Fuel
REL
Recommended Exposure Limit
RIVM
Dutch National Institute for Public Health and the Environment
RQs
Risk Quotients
SACC
Science Advisory Committee on Chemicals
SARA
Superfund Amendments and Reauthorization Act
SDS
Safety Data Sheet
SDWA
Safe Drinking Water Act
SIC
Standard Industrial Classification
SRC
SRC Inc., formerly Syracuse Research Corporation
STORET
Storage and Retrieval for Water Quality Data; EPA's repository of water quality

monitoring data
TBD
To be determined
TG
Test Guideline
TERA
Toxicology Excellence for Risk Assessment
TIAB
Title and Abstract
TK
Toxicokinetics
TLV
Threshold Limit Value
TMF
Trophic Magnification Factors
TRI
Toxics Release Inventory
TSCA
Toxic Substances Control Act
TTO
Total Toxic Organics
TURA
Toxic Use Reduction Act
TWA
Time-weighted average
UIC
Underground Injection Control
UCMR
Unregulated Contaminants Monitoring Rule
USGS
United States Geological Survey
VP
Vapor Pressure
WQX
Water Quality Exchange

-------
EXECUTIVE SUMMARY
In December 2019, EPA designated 1,1-dichloroethane (CASRN 75-34-3) 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 (40 CFR Part 702) (Docket ID: EPA-
HQ-OPPT-2018-0426). The first step of the risk evaluation process is the development of the scope
document and this document fulfills the TSCA requirement to issue a draft scope document as described
in 40 CFR 702.41(c)(7). The draft scope for 1,1-dichloroethane 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. 1,1-Dichloroethane is a colorless oily liquid with characteristic (chloroform-like)
odor. This chlorinated hydrocarbon is slightly soluble in water and slightly denser than water, but
miscible with most organic solvents.
Reasonably Available Information. EPA leveraged the data and information sources already described
in the document supporting the High-Priority Substance designation for 1,1-dichloroethane to inform the
development of this draft scope document. To further develop this draft scope document, 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 to date 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 use and inclusion in the risk evaluation. EPA is applying these systematic review
methods to collect reasonably available information regarding hazards, exposures, PESS and conditions
of use that will help inform the risk evaluation for 1,1-dichloroethane.
Conditions of Use. EPA plans to evaluate industrial and commercial uses of 1,1-dichloroethane in the
risk evaluation. 1,1-Dichloroethane is manufactured within the U.S. The chemical is processed as a
reactant. The identified processing activities also include recycling. Industrial and commercial uses
identified were non-incorporative activities, use as a processing aid, and in laboratory chemicals. No
consumer uses were identified. EPA identified these conditions of use from information reported to EPA
through CDR and TRI reporting, published literature, and consultation with stakeholders for both uses
currently in production and uses whose production may have ceased. Section 2.2 provides details about
the conditions of use within the scope of the risk evaluation.
Conceptual Model. The conceptual models for 1,1-dichloroethane are presented in Section 2.6.
Conceptual models are graphical depictions of the actual or predicted relationships of conditions of use,
exposures pathways (e.g. media), exposure routes (e.g., inhalation, dermal, oral), hazards and receptors
throughout the life cycle of the chemical substance—from manufacturing, processing, distribution in
commerce, storage, use, to release or disposal. EPA plans to focus the risk evaluation for 1,1-
dichloroethane on the following exposures, hazards, and receptors with the understanding that updates
9

-------
may happen in the final scope document after consideration of public comments and completion of the
systematic review data collection phase.
• Exposures (Pathways and Routes), Receptors and PESS. EPA plans to analyze both human and
environmental exposures resulting from the conditions of use of 1,1-dichloroethane that EPA
plans to consider in the risk evaluation. Exposures for 1,1-dichloroethane are discussed in
Section 2.3. EPA identified environmental monitoring data reporting the presence of 1,1-
dichloroethane in air, drinking water, ground water, sediment, soil, surface water, and ecological
tissue. 1,1-Dichloroethane is subject to reporting to EPA's Toxics Release Inventory (TRI) and
EPA plans to use TRI information as reasonably available information to inform 1,1-
dichloroethane's environmental release assessment. For the 2018 reporting year, 15 facilities
reported to EPA releases of 1,1-dichloroethane to water. Additional information gathered
through systematic review searches will also inform expected exposures.
EPA's plan as to evaluating environmental exposure pathways considers whether and how other
EPA-administered statutes and regulatory programs address the presence of 1,1-dichloroethane
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 1,1-dichloroethane 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 the
manufacturing, processing, use or disposal of 1,1-dichloroethane (Section 2.2.1).
-	General population exposures: EPA plans to evaluate exposure to 1,1-dichloroethane via
groundwater and fish ingestion for the general population.
-	Receptors and PESS: 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 exposures: EPA plans to evaluate exposure to 1,1-dichloroethane for
aquatic and terrestrial receptors.
Hazards. Hazards for 1,1-dichloroethane 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 1,1-dichloroethane 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 1,1-dichloroethane. Relevant mechanistic evidence will also be considered, if reasonably available,
10

-------
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 1,1-dichloroethane
identified in Section 2.4.2. The broad health effect categories include reproductive and developmental,
immunological, nervous system, and irritation effects. Studies were identified reporting information on
genotoxicity, carcinogenicity and absorption, distribution, metabolism, and excretion (ADME).
Analysis Plan. The analysis plan for 1,1-dichloroethane is presented in Section 2.7. The analysis plan
outlines the general science approaches that EPA plans to use for the various information streams (i.e.,
chemistry, fate, release and engineering, exposure, hazard) supporting the risk evaluation. The analysis
plan is based on EPA's knowledge of 1,1-dichloroethane to date which includes a partial, but ongoing,
review of identified information as described in Section 2.1. EPA plans to continue considering 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 will seek public comments on the systematic review methods supporting the risk evaluation for
1,1-dichloroethane, 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 the finalization of the scope document.
Peer Review. The draft risk evaluation for 1,1-dichloroethane will be peer reviewed. 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 702.451
11

-------
1 INTRODUCTION
This document presents for comment the scope of the risk evaluation to be conducted for 1,1-
dichloroethane 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) on June 22, 2016. The new law includes statutory requirements and deadlines for actions related
to conducting risk evaluations of existing chemicals.
TSCA § 6(b) and 40 CFR Part 702, Subpart A require the Environmental Protection Agency (EPA) to
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, in
conducting 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 (8:	) as required by TSCA § 6(b)(2)(B). 1,1-dichloroethane 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 1,1-dichloroethane. EPA leveraged the data and
information sources already collected in the documents supporting the high-priority substance
designations. In addition, EPA searched for additional data and information on physical and chemical
properties, environmental fate, engineering, exposure, environmental and human health hazards that
could be obtained from in the following general categories of sources:
1.	Databases containing publicly available, peer-reviewed literature;
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
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).
12

-------
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 will publish supplemental documentation on the
systematic review methods supporting the 1,1-dichloroethane 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 up 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 1,1-
dichloroethane upon publication of the supplemental documentation of those methods.
2.1.1 Search of Gray Literature for All Disciplines
EPA surveyed the gray literature2 and identified 58 search results relevant to EPA's risk assessment
needs for 1,1-dichloroethane. Appendix A lists the gray literature sources that yielded 58 discrete data or
information sources relevant to 1,1-dichloroethane. 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.
Gray Literature Tags by Discipline
15/58
Physical.Chemical
23/58
I Inman. I Iealth. I Iazard
48/58
Exposure
Environmental. Hazard
39/58
Engineering
0	25	50	75	100
Percent Tagged (%)
Figure 2-1. Gray Literature Tags by Discipline for 1,1-Dichloroethane
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 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.
13

-------
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 1,1-dichloroethane. 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 analyze 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 refers to title and abstract screening. Note that 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.
14

-------
Point
Point
Water Sofubtity
log KOW
Henry's Law Constant
Vapor Pressure
Vapor Density
Density
Retrieved for Full-text
Review
Included for Data
Extraction and Data
Evaluation
Dielectric Constant
590
Refractive Index
Total for TIAB:
P-Cbem
548
Supplemental Information
Exclusion
Exclusion
Figure 2-2. Peer-Reviewed Literature - Physical-Chemical Properties Search Results for 1,1-
Dichloroethane
15

-------
Bioconcentration
Photolysis
Retrieved for Full-text
Review
3400
Volatilization
Total for TIAB:
Fate
Wastewater Treatment
3372
Exclusion
Other
Figure 2-3. Peer-Reviewed Literature - Fate and Transport Search Results for 1,1-Dichloroethane
16

-------
General Facility Estimate
354
Environmental Releases
included
Occupational Exposure
,554
Figure 2-4. Peer-Reviewed Literature - Engineering Search Results for 1,1-Dichloroethane
17

-------
aquatic species (143)
biosolids/sludge (5)
foreign language (3)
consumer uses and/or products (9)
drinking water (29)
Supplemental (149)
dietary (47)
ambient air (118)
epidemiological/biomonitoring study (328)
Unique HERO IDs (1991)
~I Excluded (746)
PECO relevant (910)
~4 ground water (130)
Included (1096)
Unclear (186)
indoor air (49)
sediment (74)
soil (54)
surface water (135)
terrestrial species (157)
Figure 2-5. Peer-Reviewed Literature - Exposure Search Results for 1,1-Dichloroethane
18

-------
Human
102
ilth Model
Human
Ecotoxicological Model
267
Plan!
Retrieved for full-text
Review
Case Report/Series
8763
9283
Conference Abstract
Total for TIAB:
Hazard
Exclusion
Field Study
-—
Mechanistic
263
No
Data
PECO-relevant Isomer
Susceptible Population
Figure 2-6. Peer-Reviewed Literature - Hazard Search Results for 1,1-Dichloroethane
2.1.3 Search Results for 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, as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century
Act. EPA screened a total of 152 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 137 submissions that met the inclusion criteria in
these statements and identified 5 submissions with supplemental data. EPA excluded 10 submissions
because the reports were identified as one of the following:
•	Published report that would be identified via other peer or gray literature searches
•	Draft report of a final available submitted report
•	Letter with no attached report
19

-------
•	Submission on a different chemical
•	Ranking of chemicals for proposed evaluation
•	Protocol for human health hazard testing
•	Progress report
•	Economic impact analysis
•	Environmental impact statement for proposed equipment
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.
Table 2-1. Results of Title Screening of Submissions to EPA under Various Sections of TSCA



Physicochemical Properties
5
0
Environmental Fate and Transport
14
0
Environmental and General Population Exposure
109
1
Occupational Exposure/Release Information
12
0
Environmental Hazard
0
1
Human Health Hazard
9
3
2.2 Conditions of Use
As described in the Promised Designation of 1,1-dichloroethane (CASRN 75-34-3) as a High-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 1,1-dichloroethane,
including: published literature, company websites, and government and commercial trade databases and
publications. To identify formulated products containing 1,1-dichloroethane, 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, and when applicable, 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 included 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 1,1-dichloroethane, EPA identified those categories or subcategories of
use activities for 1,1-dichloroethane 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.
20

-------
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. Conditions of Use Included in the Scope of the Risk Evaluation
Life Cycle Slniie
Csilc»orv
Siihcsilcsorv
References
Manufacturing
Domestic Manufacturing
Domestic Manufacturing
U.S. EPA (2019b)

As a reactant
Intermediate in all other
basic organic chemical
manufacturing
U.S. EPA (2019b)
Processing



As a reactant
Intermediate in all other
chemical product and
preparation manufacturing
U.S. EPA (2019b)

Recycling
Recycling4
U.S. EPA (2019b)
Distribution in
Commerce
Distribution in Commerce
Distribution in Commerce

Industrial Use
Non-incorporative
activities
Other in all other chemical
product and preparation
manufacturing
U.S. EPA (2019b)
EPA-HO-OPPT-2018-0421 -
00.1.5.

Processing aids, specific
to petroleum production
Hydraulic fracturing
U.S. EPA (2016)
Commercial use
Other use
Laboratory chemicals
Restek (2019)
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
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, 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). As a result, EPA will
not include in this scope or in the risk evaluation the activities that the Agency has concluded do not
constitute conditions of use.
No activities were excluded for 1,1-dichloroethane.
4The Agency has included information in this draft scope document sourced from the 2012 and 2016 Chemical Data
Reporting (CDR) Rule collections. In instances where particular CDR data elements included in this document were claimed
as confidential business information (CBI), the Agency reviewed the claims and secured their declassification.
21

-------
2.2.3 Production Volume
EPA is withholding5 production volume of 1,1-dichloroethane in 2015, as reported to EPA during the
2016 CDR reporting period, to protect CBI (U.S. EPA 2017). EPA also uses pre-2015 CDR production
volume information, as detailed in the Proposed Designation c	kwoetham (CASRN 75-34-3)
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 EPA plans to consider in
the 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. Appendix
E contains more detailed descriptions (e.g., process descriptions, worker activities) for each
manufacturing, processing, distribution in commerce, use, and disposal category based on preliminary
information.
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)6
5	The initial CDR data included national production volume (released in ranges), other manufacturing information, and
processing and use information, except for information claimed by the submitter to be confidential business information
(CBI) or information that EPA is withholding to protect claims of CBI.
6	The descriptions are primarily based on the corresponding industrial function category and/or commercial and consumer
product category descriptions and can be found in EPA's Instructions for Reporting 20.1.6 TSCA Chemical Data Reporting.
22

-------
MFGTMPORT
1,1-DICHLOROE THANE (CASRN 75-34-3)
PROCESSING	INDUSTRIAL AND/OR COMMERCIAL USES
	h
As a Reactant
e.g. Intermediate in all other
basic organic chemical and
chemical product and
preparation manufacturing
Manufacture
(Including
Import)
(PY withheld)
Other
e.g. Laboratory and Analytical uses
N on-incorporative Activities
e.g. Other in all other chemical product
and preparation manufacturing
Processing aids, specific to petroleum
production
e.g. Hvdraulic tracking
Disposal
Recycling
See Conceptual Model for
Environmental Releases
and Wastes
~ Manufacture (Including Import}
Processing
Industrial and/or Commercial
uses
Figure 2-7. 1,1-Dichloroethane Life Cycle Diagram
Volume is not depicted in the life cycle diagram for processing and industrial and commercial uses as specific production volume is claimed confidential
business information (CBI) or withheld pursuant to TSCA section § 14.
23

-------
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 for 1,1-dichloroethane.
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 take into account, where
relevant, the duration, intensity (concentration), frequency and number of exposures in characterizing
exposures to 1,1-dichloroethane.
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 the Proposed Designation of lJ-Dichloroetham (CASRN 75-34-3) as a High-Priority
Substance for Risk Evaluation (U.S. EPA (2019a)) to support the development of the risk evaluation for
1,1-dichloroethane. EPA plans to use the physical and chemical properties described in the Proposed
(U.S. EPA (2019a)) to support the development of the risk evaluation for 1,1-dichloroethane (Appendix
B). 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 1,1-dichloroethane. EPA plans to use the environmental fate
characteristics described in the Proposed Designation o t /, ( i\ ikwoetham (CASRN 75-3-' r*a
High-Priority Substance for Risk Evaluation (U.S. EPA (2019a)) to support the development of the risk
evaluation for 1,1-dichloroethane. The values for the environmental fate properties (Appendix C) may
be updated as EPA collects additional information through systematic review methods.
2.3.3	Releases to the Environment
Releases to the environment from conditions of use 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 Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA), 1,1-
dichloroethane is a TRI-reportable substance, under the name ethylidene dichloride, effective January
01, 1994 (40 CFR 372.65). For TRI reporting7, facilities in covered sectors in the United States are
required to disclose releases and other waste management activity quantities of 1,1-dichloroethane under
' For TRI reporting criteria see https://www.epa.gov/toxics-release-inventore-tri-prograin/basics-tri-re
24

-------
the CASRN 75-34-3 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 1,1-dichloroethane reported by
facilities to the TRI program for reporting year 2018.8 As shown in the table, 15 facilities reported a total
of nearly 15 million pounds of 1,1-dichloroethane waste managed. Of this total, over 10.5
million pounds were treated, nearly three million pounds were combusted for energy recovery, nearly
1.4 million pounds were recycled, and over nine thousand pounds were disposed of or otherwise
released into the environment.
Table 2-3. Summary of 1,1-Dichloroethane TRI Production-Related Waste Managed in 2018



Rcco\crcd for

Released
Tolsil Production

Number of
Recycled
Kner»\
Trcsilcd
Relcsiscd'
Rchitcd Wsislc
^ esir
l-'sicililics
(lbs)
(lbs)
(lbs)
(lbs),,lM
(lbs)
2018
15
1,394,654
2,999,941
10,575,018
9,151
14,978,743
Data source: (U.S. EPA, 2018b) (Updated November 2019)
a 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 the quantities of 1,1-dichloroethane released to the environment during
2018.8 All of the quantities reported as released to the environment occurred on site and to air, mostly as
fugitive emissions.
Table 2-4. Summary of Releases of 1,1-Dichloroethane to the Environment During 2018


Air Kclcsiscs

1 .silid Dispossil



Nu 111 her
ol'
l-'sicililics
Sisick Air
Kclcsiscs
(Ills)
l"iiiiili\c
Air
Kclcsiscs
(ll)S)
\\ siler
Kclcsiscs
(Ills)
( Isiss 1
I mler-
uroiunl
Injection
I ll)S)
KCKA
Subtitle (
I.SIIKllills
(ll)S)
All oilier
I.siihI
Dispossil'1
(Ihs)
Oilier
Kclcsiscs
(Ihsr'Kcle
SISCS'1
(Ihs)
Tolsil Kclcsiscs
(Ihs)1'
Kclcsiscs1' '
(Ihs)
Totals
15
3,283
5,868
0
0
0
0
0
9,151


9,151
0


Data source: (U.S. EPA, 2018b) (Updated November 2019)
a 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 1,1-dichloroethane, the total release
quantities shown in the two tables are the same, but for other TRI chemicals they may differ slightly and
may further reflect differences in TRI calculation methods for reported release range estimates (U.S.
EPA. 2017dY
8 Reporting year 2018 is the most recent TRI data available. Data presented in Table 2-3 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.
25

-------
2.3.4	Environmental Exposures
The manufacturing, processing, distribution, use and disposal of 1,1-dichloroethane 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, and partitioning across different media. Concentrations of chemical substances in biota
provide evidence of exposure. EPA plans to review available environmental exposure data in biota in the
risk evaluation. Monitoring data were identified in the EPA's data search for 1,1-dichloroethane and can
be used in the exposure assessment. Relevant and reliable monitoring studies provide(s) information that
can be used in an exposure assessment. Monitoring studies that measure environmental concentrations
or concentrations of chemical substances in biota provide evidence of exposure.
EPA plans to review available environmental monitoring data in the risk evaluation. EPA's Ambient
Monitoring Technology Information Center Air Toxics database has identified 1,1-dichloroethane in air
(	to). In addition, EPA's Unregulated Contaminant Monitoring Rule has identified 1,1-
dichloroethane in drinking water (	6). USGS's Monitoring Data - National Water Quality
Monitoring Council has identified 1,1-dichloroethane in air, ground water, sediment, soil, surface water,
and ecological tissue (e.g., fish tissue concentrations) (USGS 1991a-g).
Based on fate properties, such as vapor pressure, Henry's Law constant, soil mobility and water
solubility, EPA anticipates possible presence of 1,1-dichloroethane in ambient air, and to a lesser extent
in surface water, groundwater, and soil (ATSDR 2015. RIYM. 2007). Existing assessments reported 1,1-
dichloroethane in ambient air, waste gas from garbage dumps, surface water, groundwater, drinking
water, and other environmental media ( V 1 '• )R . 1 > \ „ ,11 <' t .^03).
2.3.5	Occupational Exposure
EPA plans to analyze worker activities where there is a potential for exposure under the various
conditions of use described in Section 2.2.1. In addition, EPA plans to analyze 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 plans to consider the effect(s) that engineering controls (EC)
and/or personal protective equipment (PPE) have on occupational exposure levels as part of the draft
risk evaluation.
Worker activities associated with conditions of use within the scope of the risk evaluation for 1,1-
dichloroethane will be analyzed, including but not limited to:
•	Unloading and transferring 1,1-dichloroethane to and from storage containers to process vessels;
•	Handling, transporting and disposing of waste containing 1,1-dichloroethane;
•	Cleaning and maintaining equipment;
•	Sampling chemicals, formulations or products containing 1,1-dichloroethane for quality control;
•	Repackaging chemicals, formulations or products containing 1,1-dichloroethane;
1,1-Dichloroethane has a vapor pressure of approximately 230 mmHg at 25°C (Appendix B). Based on
the chemical's high volatility, EPA anticipates that workers and ONUs will be exposed to vapor via the
inhalation route. EPA plans to analyze inhalation exposure to vapor in occupational exposure scenarios
where 1,1-dichloroethane is used and handled; the extent of exposure could vary from facility to facility
depending on many factors including but not limited to EC, type of facility, and facility design. Based
on the conditions of use presented in Section 2.2.1, EPA has not yet identified scenarios where there is
inhalation exposure to mist.
26

-------
1,1-Dichloroethane has an Occupational Safety and Health Administration (OSHA.. 2009) Permissible
Exposure Limit (PEL)9 of 100 ppm or 400 mg/m3 over an 8-hour work day, time weighted average
(TWA). This chemical also has a National Institute for Occupational Safety and Health (NIOSH., 2005)
Recommended Exposure Limit (REL)10 of 100 ppm (400 mg/m3) TWA. The American Conference of
Governmental Industrial Hygienists (ACGIH) sets the Threshold Limit Value (TLV) at 100 ppm TWA.
Based on the conditions of use, EPA also plans to analyze worker exposure to liquids via the dermal
route. EPA does not plan on analyzing dermal exposure for ONUs because they do not directly handle
1,1 -dichloroethane.
EPA generally does not evaluate occupational exposures through the oral route. 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.
2.3.6	Consumer Exposure
No consumer conditions of use were found for 1,1-dichloroethane. The 2012 CDR, 2016 CDR, and the
National Institutes of Health Consumer Product Database did not report on the use of 1,1-dichloroethane
in consumer products.
2.3.7	General Population Exposures
Releases of 1,1-dichloroethane from certain conditions of use, such as manufacturing, processing,
disposal, or hazardous waste treatment activities, may result in general population exposures, mostly via
inhalation of ambient air and ingestion of contaminated drinking water near emission sources, whereas
presence in food sources is considered very unlikely (ATSDR2015. CalEPA 2003). Populations living
near source areas, such as petrochemical factories, where 1,1-dichloroethane is manufactured or used,
are expected to have higher exposures via inhalation. Low levels (<0.49 ppb) of 1,1-dichloroethane were
found in personal air monitoring samples near petrochemical factories (ATSDR 2015). 1,1-
Dichloroethane has been found at levels ranging from 0.51 ppb to 30 ppb in drinking water (CalEPA
2003). Exposure to 1,1-dichloroethane may occur via drinking water ingestion, dermal contact, and
inhalation from air releases.
Blood concentrations of 1,1-dichloroethane were below the level of detection (0.01 ng/mL) in 2,736
individuals who participated in the National Health and Nutrition Examination Survey (NHANES)
2011-2012 subsample of the U.S. population (CDC, 2019).
2.4 Hazards (Effects)
2.4.1 Environmental Hazards
As described in the Promised Designation of 1,1-Dichloroethane (CASRN 75-34-3) as a Hieh-Priority
Substance for Risk Evaluation (U.S. EPA 2019a), EPA considers all the potential environmental hazards
for 1,1-dichloroethane identified during prioritization. EPA is in the process of identifying additional
9	OSHA, 2009. Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELs).
https://www.osha.gov/dsg/annotated-pels/tablez-l.html
10	NIOSH, 2005. NIOSH Pocket Guide to Chemical Hazards, https://www.cdc.gov/niosli/npg/npgdcas.html
27

-------
reasonably available information through systematic review methods and public comments, which may
update the list of potential environmental hazards associated with 1,1-dichloroethane exposure. If
necessary, EPA will update the list of potential hazards in the final scope document of 1,1-
dichloroethane. 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 Promised Designation of IJ-Dichloroethane fCASRN 75-34-3) as a Hieh-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 1,1-
dichloroethane. EPA plans to evaluate all of the potential human health hazards for 1,1-dichloroethane
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 toxicity, immunotoxicity, neurotoxicity,
carcinogenicity, epidemiological or biomonitoring studies and ADME. The broad health effect
categories include developmental, dermal, and other irritation effects. Studies were also identified
reporting information on genotoxicity, carcinogenicity and toxicokinetics. 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. If necessary, EPA will update the list of potential hazards in the final scope document of the
1,1-dichloroethane risk evaluation.
2.5 Potentially Exposed or Susceptible Subpopulations
TSCA 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 (	11).
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 2019a). 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 (	06a). 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).
28

-------
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 1,1-ichloroethane. Pathways and
routes of exposure associated with workers and occupational non-users 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 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
Figure 2-8 illustrates the conceptual model for the pathways of exposure from industrial and commercial
activities and uses of 1,1-dichloroethane that EPA plans to include in the risk evaluation. There is
potential for exposures to workers and/or ONUs 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
disposed in wastewater treatment, incineration or via other disposal methods. EPA intends 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. For each condition of use
identified in Table 2-2, a determination was made as to whether or not each combination of exposure
pathway, route, and receptor will be further analyzed in the risk evaluation. The results of that analysis
along with the supporting rationale are presented in Appendix F.
29

-------
INDUSTRIAL AND
comtfEmtM n\ r r rf >
uses
JMiivtij :*
i MIHWXT EXPOSURE ROUTE
SECEFTORS
Manafaeniring
{incJhtdiag
Import)
Processing
As i t'ftftaunt
Km-
i«€©t|®-:r»t§«
activities
Processing aids.
He
production
Otter Ust
Liitrateiy
Clifinictls

4
fifiitw
Emissions
HAZARDS

laotr

r. ^
>	¥
Hazards

potentially

associated wiffc

Ktt and/or

cittwafc eipdsires
h	~
Wist* BwriHu
Tmtma . ¦
w Wastewater, M§vii Wastes, ondSotkl Wesm
~ (See Environmental Release Ctntxptml Models)
Figure 2-8.1,1-Dichloroethane Occupational Exposure 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 1,1-
dichloroethane
30

-------
2.6.2	Conceptual Model for Consumer Activities and Uses
EPA does not expect consumer exposures as no consumer conditions of use were found for 1,1-
dichloroethane, therefore, no conceptual model is presented.
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 1,1-dichloroethane 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 1,1-dichloroethane in
exposure pathways falling under the jurisdiction of these EPA statutes.
The conceptual model in Figure 2-9 presents the potential exposure pathways, exposure routes and
hazards to human and environmental receptors from releases and waste streams associated with
industrial and commercial uses of 1,1-dichloroethane. This figure includes overlays, labeled and shaded
to depict the regulatory programs (e.g., CAA, SDWA, CWA, RCRA) and associated pathways that EPA
considered in developing this conceptual model for the draft scope document. The pathways are further
described in Section 2.6.3.1 through Section 2.6.3.4.
31

-------
RELEASES AND WASTES FROM
INDUSTRIAL / COMMERCIAL /
CONSUMER USES
EXPOSURE PATHWAYS
EXPOSURE
ROUTES
RECEPTORS
Wastewater or
Liquid Wastes
Solid Wastes
Liquid Wastes
Emissions to Air
Industrial Pre-
Treatment or
Industrial WWT
Indirect discharge
~	
RCRA- Haz List
Underground
Injection
Hazardous and
Municipal Waste
Landfill
Hazardous and
Municipal Waste
Incinerators
Off-site Waste
Transfer
Recycling, Other
Treatment
Water, Scdiinc
_r
SDWA
Fish Ingestion
Aquatic
Species
Drinking
Biosohds
\\ ater
Hazards Potentially
Associated with
Acute and/or Chronic
and
Disposal
General
Dermal
Population
exposures
Ground 1
Water J
Inhalation
Terrestrial
Species
CAA-HAP
Fugitive Emissions
Figure 2-9. 1,1-Dichloroethane Conceptual Model for Environmental Releases and Wastes: Environmental 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
1,1-dichloroethane showing the environmental statutes covering those pathways.
a)	Industrial wastewater or liquid wastes may be treated on-site and then released to surface water (direct discharge), or pre-treated and released to POTW (indirect
discharge). Drinking water will undergo further treatment in drinking water treatment plant. Ground water may also be a source of drinking water.
b)	Receptors include potentially exposed or susceptible subpopulations (see Section 2.5).
c)	For regulation of hazardous and municipal waste incinerators and municipal waste landfills CAA and RCRA may have shared regulatory authority.
32

-------
2.6.3.1	Ambient Air Pathway
The Clean Air Act (CAA) contains a list of hazardous air pollutants (HAP) and provides EPA with the
authority to add to that list pollutants that present, or may present, a threat of adverse human health
effects or adverse environmental effects. For stationary source categories emitting HAP, the CAA
requires issuance of technology-based standards and, if necessary, additions or revisions to address
developments in practices, processes, and control technologies, and to ensure the standards adequately
protect public health and the environment. The CAA thereby provides EPA with comprehensive
authority to regulate emissions to ambient air of any hazardous air pollutant. 1,1-Dichloroethane is a
HAP. EPA has issued a number of technology-based standards for source categories that emit 1,1-
dichloroethane to ambient air and, as appropriate, has reviewed, or is in the process of reviewing
remaining risks.
Emission pathways to ambient air from commercial and industrial stationary sources and associated
inhalation exposure of the general population or terrestrial species in this TSCA evaluation from
stationary source releases of 1,1-dichloroethane to ambient air are covered under the jurisdiction of the
CAA. EPA's Office of Air and Radiation and Office of Pollution Prevention and Toxics will continue to
work together to provide an understanding and analysis of the CAA regulatory analytical processes and
to exchange information related to toxicity and occurrence data on chemicals undergoing risk evaluation
under TSCA.
2.6.3.2	Drinking Water Pathway
EPA has regular analytical processes to identify and evaluate drinking water contaminants of potential
regulatory concern for public water systems under the Safe Drinking Water Act (SDWA). Under SDWA
EPA must also review and revise "as appropriate" existing drinking water regulations every 6 years.
The Contaminant Candidate List (CCL) is a list of unregulated contaminants that are known or
anticipated to occur in public water systems and that may require regulation. EPA must publish a CCL
every 5 years and make Regulatory Determinations (RegDet) to regulate (or not) at least five CCL
contaminants every 5 years. To regulate a contaminant EPA must conclude the contaminant may have
adverse health effects, occurs or is substantially likely to occur in public water systems at a level of
concern and that regulation, in the sole judgement of the Administrator, presents a meaningful
opportunity for health risk reduction.
Once contaminants have been placed on the CCL, EPA identifies if there are any additional data needs,
including gaps in occurrence data for evaluation under Regulatory Determination; if sufficient
occurrence data is lacking, the contaminant may be considered for monitoring under the Unregulated
Contaminant Monitoring Rule.
1,1-Dichloroethane is also currently listed on EPA's Fourth Contaminant Candidate List (CCL 4) and
was subject to occurrence monitoring in public water systems under the third Unregulated Contaminants
Monitoring Rule (UMCR 3). Under UMCR 3, water systems were monitored for 1,1-dichloroethane
during 2013-2015. Of the 4,916 water systems monitored, 244 systems had detections of 1,1-
dichloroethane in at least one sample. In accordance with EPA-OW's process, a Preliminary Regulatory
Determination to not regulate (i.e. develop a drinking water standard) for 1,1-dichloroethane process
under SDWA was published in February 2020.
33

-------
2.6.3.3	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 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 1,1-dichloroethane. 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.
EPA has not developed CWA section 304(a) recommended water quality criteria for the protection of
human or aquatic life for 1,1-dichloroethane, so there are no national recommended criteria for this use
available for adoption into state water quality standards and available for use in NPDES permits. EPA
may publish CWA section 304(a) ambient water quality criteria and/or aquatic life criteria for 1,1-
Dichloroethane in the future if it is identified as a priority under the CWA.
2.6.3.4	Disposal and Soil Pathways
1,1-Dichloroethane is included on the list of hazardous wastes pursuant to RCRA 3001 (40 CFR §§
261.33) as a listed waste on the U076 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 relatedfactors
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)).
Emissions to ambient air from municipal and industrial waste incineration and energy recovery units that
form combustion by-products from incineration treatment of 1,1-dichloroethane wastes may be subject
to regulations, as would 1,1-dichloroethane burned for energy recovery.
EPA has not identified releases to land that go to RCRA Subtitle C hazardous waste landfills. Based on
2018 reporting, TRI land disposal includes Subtitle C landfills (0 pounds) and nothing reported as
transferred to "other landfills" both on-site and off-site (0 pounds reported 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
34

-------
being disposed in Subtitle C landfills must also meet RCRA waste treatment standards before disposal.
Given these controls, general population exposure in groundwater from Subtitle C landfill leachate is not
expected to be a significant pathway.
1,1-Dichloroethane is present in commercial and consumer products that may be disposed of in landfills,
such as 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-dichloroethane. While permitted and managed by the individual states, municipal solid
waste 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 lbs
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 1,1-dichloroethane. Industrial non-hazardous and construction/demolition waste landfills are
primarily regulated under authorized state regulatory programs, but states must implement 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
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 2-10 presents the exposure pathways, exposure routes and hazards to human and environmental
receptors from releases and wastes from industrial and commercial uses of 1,1-dichloroethane 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 1,1-
dichloroethane in exposure pathways falling under the jurisdiction of these EPA statutes.
The diagram shown in Figure 2-10 includes releases from industrial, commercial and/or consumers 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 via ingestion of water and
fish consumption. The supporting basis for general population and environmental pathways considered
for 1,1-dichloroethane are included in Appendix G.
35

-------
RELEASES AND WASTES FROM
INDUSTRIAL COMMERCIAL
CONSUMER USES
EXPOSURE PATHWAYS
EXPOSURE
ROUTES
RECEPTORS HAZARDS
Wastewater or
Liquid Wastes
Industrial Pre-
Treatment or
Industrial WWT


I
Indirect discharge
*
POTW



~ Water, Sedime
Biosolids
CAA
RCRA
SDWA
CWA
Aquatic
Fish Ingestion
I
General
Population
Dermal
Ground
Water
Land
Disposal
Hazards Potentially
Associated with
Acute and'or Chronic
Exposures
Figure 2-10.1,1-Dichloroethane Conceptual Model for Environmental Releases and Wastes: Environmental Exposures and Hazards
The conceptual model presents the exposure pathways, exposure routes and hazards to human and ecological receptors from releases and wastes from industrial and
commercial uses of 1.1 -dicliloroethane with regulatory overlay pathways removed.
a)	Industrial wastewater or liquid wastes may be treated on-site and then released to surface water (direct discharge), or pre-treated and released to POTW (indirect
discharge).
b)	Receptors include potentially exposed or susceptible subpopulations (see Section 2.5).
36

-------
2.7 Analysis Plan
The analysis plan is based on EPA's knowledge of 1,1-dichloroethane 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 considering new information submitted by the public. Should
additional data or approaches become available, EPA may update its analysis plan in the final scope
document. As discussed in the Application of Systematic Review in TSCA Risk Evaluations document
[EPA Document #740-P1-8001], targeted supplemental searches during the analysis phase may be
necessary to identify additional information (e.g., commercial mixtures) for the risk evaluation of 1,1-
dichloroethane.
2.7.1 Physical and Chemical Properties and Environmental Fate
EPA plans to analyze the physical-chemical properties and environmental fate and transport of 1,1-
dichloroethane as follows:
1)	Review reasonably available measured or estimated physical-chemical properties 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 physical-chemical properties (Appendix B) and fate endpoints
(Appendix C) previously summarized in the Proposed Designation of 1,1-DicMoroethane
(CASRN 75-34-3) as a Hieh-Prioritv 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 physical-chemical
properties 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 1,1-
dichloroethane 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.
37

-------
3) Conduct a weight-of-evidence evaluation of physical-chemical properties and
environmental fate data, including qualitative and quantitative sources of information.
During risk evaluation, EPA plans to evaluate and integrate the physical-chemical properties and
environmental fate 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 Exposure
EPA plans to analyze exposure levels for surface water, sediment, soil, aquatic biota, and terrestrial
biota associated to exposure to 1,1-dichloroethane. EPA has not yet determined the exposure levels in
these media or how they may be applied 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 1,1-dichloroethane are presented in Appendix G. 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 plans 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 key data sources containing information on processes and activities
resulting in releases, and the information found is described in Appendix E. EPA plans to
continue reviewing data sources identified in Appendix E during risk evaluation using the
evaluation strategy in the systematic review documentation that EPA plans to publish prior to
finalizing the scope document. Potential sources of environmental release data are summarized
in Table 2-5 below:
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 1,1-dichloroethane 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 reviewing
relevant data sources as identified in 2.8E.2 during risk evaluation. EPA plans to match
identified data to applicable conditions of use and identify data gaps where no data are found for
38

-------
particular conditions of use. EPA plans to address data gaps identified as described in steps 3 and
4 below by considering potential surrogate data and models.
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 ChemSTEEl (
2013).
3)	Review reasonably available measured or estimated release data for surrogate chemicals
that have similar uses and physical properties.
If surrogate data are identified, these data will be matched with applicable conditions of use for
potentially filling data gaps. Measured or estimated release data for other chlorinated solvents
and/or chemicals with similar physical properties (e.g. vapor pressure) may be considered as
surrogates for 1,1-dichloroethane.
4)	Review reasonably available data that may be used in developing, adapting or applying
exposure 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 »D on Chemical Industry
(OECD, 2011) may be useful. EPA plans 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.org/chemicalsafetv/risk-assessment/emissionscenariodocuments.htm
EPA was not able to identify ESDs or GSs corresponding to some conditions of use; EPA plans
to perform additional targeted research to understand those conditions of use which may inform
identification of release scenarios. EPA may also need to perform targeted research for
applicable models and associated parameters that EPA may use to estimate releases for certain
conditions of use. If ESDs and GSs are not available, other methods may be considered.
Additionally, for conditions of use where no measured data on releases are available, EPA may
use a variety of methods including the application of default assumptions such as standard loss
fractions associated with drum cleaning (3%) or single process vessel cleanout (1%).
39

-------
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.
7)	Evaluate the weight of the scientific evidence of environmental release data.
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. The data integration strategy will be
designed to be fit-for-purpose in which EPA will use systematic review methods to assemble the
relevant data, evaluate the data for quality and relevance, including strengths and limitations,
followed by synthesis and integration of the evidence.
2.7.2.2 Environmental Exposures
EPA plans to analyze the following in developing its environmental exposure assessment of 1,1-
dichloroethane:
1)	Review available environmental and biological monitoring data for all media relevant to
environmental exposure.
For 1,1-dichloroethane, environmental media which will be analyzed include aquatic and
terrestrial species, sediment, soil, and surface 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 1,1-dichloroethane 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 1,1-dichloroethane in the environment or biota with specific
sources or groups of sources will be evaluated.
40

-------
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
1,1-dichloroethane, the following are noteworthy considerations in constructing exposure
scenarios for environmental receptors:
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 plans 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 plans 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 for 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. EPA has also identified additional data
sources that may contain relevant monitoring data for the various conditions of use. EPA plans to
review these sources (identified in Table 2-6) and extract relevant data for consideration and
analysis during risk evaluation.
OSHA has established a permissible exposure limit (PEL) of 100 ppm 8-hour time-weighted
average (TWA) (OSHA. 2019) . EPA will consider the influence of these regulatory limits and
recommended exposure guidelines on occupational exposures in the occupational exposure
assessment. The following are some data sources identified thus far:
41

-------
Table 2-6. Potential Sources of Occupational Exposure Data	
2012 ATSDR Toxicological Profile for 1,1 -dichloroethane	
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 1,1-dichloroethane.
If surrogate data are identified, these data will be matched with the 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 emission scenario documents (ESDs). For
example, September 2(	i. the Chemical Industry (OECD, 2011) may be used to estimate
occupational exposures. EPA plans to critically review these ESDs to determine their
applicability to the conditions of use assessed. EPA was not able to identify ESDs or GSs
corresponding to the use of 1,1-dichloroethane as a laboratory chemical. EPA plans to perform
additional targeted research in order to better 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 #2 and #3 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 occupational non-users.
5)	Consider and incorporate applicable engineering controls (EC) and/or PPE into exposure
scenarios.
EPA plans to review potentially relevant data sources on EC and personal protective equipment
as identified in Appendix E to determine their applicability and incorporation into exposure
scenarios during risk evaluation. EPA plans to assess worker exposure pre- and post-
implementation of EC, using reasonably available information on available 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 has identified occupational exposure scenarios and mapped them to relevant conditions of
use (see Appendix F). EPA was not able to identify occupational scenarios corresponding to
some conditions of use. EPA plans to perform targeted research to understand those uses which
may inform identification of occupational exposure scenarios. EPA may further refine the
42

-------
mapping of 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.
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 will use systematic review methods
to assemble the relevant data, evaluate the data for quality and relevance, including strengths and
limitations, followed by synthesis and integration of the evidence.
2.7.2.4	Consumer Exposures
EPA does not plan on analyzing consumer exposures to 1,1-dichloroethane because no consumer
conditions of use were identified.
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 1,1-dichloroethane, 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.
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
43

-------
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 Appendix G. 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 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 quantitative. First-tier analyses were conducted during problem
formulation and are expected to continue during risk evaluation. 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 1,1-dichloroethane, media where exposure models will be considered for general population
exposure include models that estimate 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 1,1-dichloroethane chemical assessment may be applicable to the 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 1,1-dichloroethane 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
44

-------
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 1,1-dichloroethane, 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 soil
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 systematic review methods described in the systematic review
documentation that EPA plans to publish prior to finalizing the scope document.
2.7.3 Hazards (Effects)
2.7.3.1 Environmental Hazards
EPA plans to conduct an environmental hazard assessment of 1,1-dichloroethane 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 1,1-dichloroethane 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 (e.g.,
analogue and read-across data) when characterizing the potential hazards of 1,1-dichloroethane
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.
45

-------
Hazard endpoints (e.g., mortality, growth, immobility, reproduction) will be evaluated, while
considering data availability, relevance, and quality.
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 1,1-dichloroethane 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 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 1,1-dichloroethane conceptual model. These organisms may be exposed to 1,1-
dichloroethane via a number of environmental pathways (e.g., surface water, sediment, soil,
diet).
5)	Conduct an environmental risk characterization of 1,1-Dichloroethane.
EPA plans to conduct a risk characterization of 1,1-dichloroethane to identify if there are risks to
the aquatic and/or terrestrial environments from the measured and/or predicted concentrations of
1,1-dichloroethane 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 (U.S. EPA. 1998; Barnthouse et at.. 1982).
6)	Consider a Persistent, Bioaccumulative, and Toxic (PBT) Assessment of 1,1-
Dichloroethane.
EPA plans to consider the persistence, bioaccumulation, and toxic (PBT) potential of 1,1-
dichloroethane 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 1,1-dichloroethane. 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 1,1-
dichloroethane 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).
46

-------
EPA will use systematic review methods to evaluate the epidemiological and toxicological
literature for 1,1-dichloroethane. EPA will publish the systematic review documentation 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
PESS may have greater susceptibility than the general population to 1,1-dichloroethane
hazard(s). Susceptibility of particular populations or subpopulations to 1,1-dichloroethane will be
determined by evaluating information on factors that influence susceptibility.
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 1,1-dichloroethane 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.
2012a. 2011. 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 1,1-dichloroethane, 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 (	€5).
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.
47

-------
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 The 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 exposure). If application of the PBPK
model is not possible, oral PODs may be adjusted by BW3'4 scaling in accordance with
iZ , 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.
Following systematic review, EPA plans to conduct a dose-response analysis and/or benchmark
dose modeling for the oral route of exposure based on the results. This may include using route-
to-route extrapolation methods where appropriate. EPA also intends to evaluate any potential
human health hazards following dermal and inhalation exposure to 1,1-dichloroethane, 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.
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 The EPA guidance document Risk Assessment Guidance for
Superfund Volume I: Human Health Evaluation Manual (Part E, Supplemental Guidance for
Dermal Risk Assessment) (U.S. EPA. 2004) 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 The EPA's Risk
Characterization Handbook (U. S. EPA. 2000). As defined in The EPA's Risk Characterization Policy.
"the risk characterization integrates information from the preceding components of the risk evaluation
48

-------
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.
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 (	KMX) and consistent with the requirements of
the Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (82 PR
6). For instance, in the risk characterization summary, the EPA will further carry out the obligations
under TSCA section 26; for example, by identifying and assessing uncertainty and variability in each
step of the risk evaluation, discussing considerations of data quality such as the reliability, relevance and
whether the methods utilized were reasonable and consistent, explaining any assumptions used, and
discussing information generated from independent peer review.
The EPA will also be guided by the EPA's Information Quality Guidelines (U.S. 2002) as it provides
guidance for presenting risk information. Consistent with those guidelines, the EPA will identify in the
risk characterization the following: (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 1,1-dichloroethane will be peer reviewed.
49

-------
REFERENCES
ATSDR (Agency for Toxic Substances and Disease Registry). (2015). Toxicological profile for 1,1-
dichloroethane. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service,
Agency for Toxic Substances and Disease Registry. https://www.atsdr.cdc.gov/ToxProfiles/tpl33.pdf.
HERO ID: 5160114
CDC (Centers for Disease Control and Prevention). (2019). National Health and Nutrition Examination
Survey data (NHANES). Atlanta, Georgia: Centers for Disease Control, National Center for Health
Statistics, https://www.cdc.gov/nchs/nhanes/index.htm. HERO ID: 6124532
CDPH (California Department of Public Health). (2015). Biomonitoring California. Priority chemicals.
December 2015. http://www.biomonitoring.ca.gov/chemicals/priority-chemicals. HERO ID: 3859897
CDTSC (California Department of Toxic Substances Control). (2017). Informational list of candidate
chemicals and chemical groups, https://calsafer.dtsc.ca.gov/chemical/search.aspx. HERO ID: 4491939
Dreher, EL;Beutel, KK;Myers, JD;Liibbe, T;Krieger, S;Pottenger, LH. (2014). Chloroethanes and
chloroethylenes. In B Elvers (Ed.), Ullmann's Encyclopedia of Industrial Chemistry (6th ed., pp. 1-81).
Hoboken, NJ: Wiley-VCH Verlag GmbH & Co. http://dx.doi.org/10.1002/14356007.o06_o01.pub2.
HERO ID: 4293766
Environmental Technology Council Hazardous Waste Resources, C. (2018). High Temperature
Incineration. Washington D.C.: Environmental Technology Council Hazardous Waste Resources
Center, http://etc.org/advanced-technologies/high-temperature-incineration.aspx. HERO ID: 5071451
HSDB (Hazardous Substances Data Bank). (2018). 1,1-Dichloroethane (CASRN: 75-34-3) [Website],
National Library of Medicine, http://toxnet.nlm.nih.gov/cgi-
bin/sis/search2/r?dbs+hsdb:@term+@DOCNO+64. HERO ID: 5332607
Jeffers, PM;Ward, LM;Woytowitch, LM;Wolfe, NL. (1989). Homogeneous hydrolysis rate constants for
selected chlorinated methanes, ethanes, ethenes, and propanes. Environ Sci Technol 23: 965-969.
http://dx.doi.org/10.1021/es00066a006. HERO ID: 661098
Kwok, ESC;Atkinson, R. (1994). Estimation of hydroxyl radical reaction rate constants for gas-phase
organic compounds using a structure-reactivity relationship: An update. (CMA Contract No. ARC-8.0-
OR). Riverside, CA: University of California. HERO ID: 5185218
Lewis, RJ, Sr;Sax, NI. (2004). Sax's Dangerous Properties of Industrial Materials (11th ed.). Hoboken,
NJ: John Wiley & Sons. HERO ID: 699583
Lyman, WJ;Reehl, WF;Rosenblatt, DH. (1990). Handbook of Chemical Property Estimation Methods
(pp. 8-3). Washington, DC: American Chemical Society. HERO ID: 5352577
NFPA (National Fire Protection Association). (2010). Fire protection guide to hazardous materials (14th
ed ). Quincy, MA. HERO ID: 2991057
NICNAS (National Industrial Chemicals Notification and Assessment Scheme). (2015). Ethane, 1,1-
dichloro-: Human health tier II assessment. Sydney, Australia: Australian Department of Health,
National Industrial Chemicals Notification and Assessment Scheme.
https://www.nicnas.gov.au/chemical-information/imap-assessments/imap-assessment-
details?assessment id=1338#cas-A 75-34-3. HERO ID: 5155547
50

-------
NOAA (National Oceanic and Atmospheric Administration). (2018). CAMEO chemicals. Database of
hazardous materials. 1,1-Dichloroethane (75-34-3). Available online at http://cameochemicals.noaa.gov/
HERO ID: 5185289
OEHHA (California Office of Environmental Health Hazard Assessment). (2020). Cal Code Regs. Title
27, § 27001: Chemicals known to the state to cause cancer or reproductive toxicity. (California Code of
Regulations Title 27 Section 27001).
https://govt.westlaw.com/calregs/Document/I54B9D2B0D4501 lDEA95CA4428EC25FA0?contextData
=%28sc.Default%29&transitionType=Default. HERO ID: 6305878
Restek Corporation. (2019). 1,1-Dichloroethane.
https://www.restek.com/documentation/msds/30276_useng.pdf. HERO ID: 6305891
RIVM (National Institute for Public Health and the Environment (Netherlands)). (2007).
Ecotoxicologically based environmental risk limits for several volatile aliphatic hydrocarbons (pp. 217).
(601782002/2007). Bilthoven, Netherlands: National Institute for Public Health and the Environment
(RIVM). https://www.rivm.nl/bibliotheek/rapporten/601782002.pdf. HERO ID: 5159900
Sabljic, A;Giisten, H;Verhaar, H;Hermens, J. (1995). QSAR modelling of soil sorption. Improvements
and systematics of log KOC vs. log KOW correlations. Chemosphere 31: 4489-4514.
http://www.sciencedirect.com/science/article/pii/0045653595003275. HERO ID: 5185273
Tabak, HH;Quave, SA;Mashni, CI;Barth, EF. (1981). Biodegradability studies with organic priority
pollutant compounds. Journal of Water Pollution Control Federation 53: 1503-1518. HERO ID: 9861
Tomer, A;Kane, J. (2015). The great port mismatch. U.S. goods trade and international transportation.
The Global Cities Initiative. A joint project of Brookings and JPMorgon Chase.
https://www.brookings.edu/wp-content/uploads/2015/06/brgkssrvygcifreightnetworks.pdf. HERO ID:
5018559
U.S. EPA (U.S. Environmental Protection Agency). (1996). EPA Unregulated Contaminant Monitoring
Rule (UCMR). https://www.epa.gov/dwucmr. HERO ID: 6126665
U.S. EPA. (U.S. Environmental Protection Agency). (2006). A framework for assessing health risk of
environmental exposures to children (pp. 1-145). (EPA/600/R-05/093F). Washington, DC: U.S.
Environmental Protection Agency, Office of Research and Development, National Center for
Environmental Assessment. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=158363. HERO ID:
194567
U.S EPA. (U.S. Environmental Protection Agency). (2011). Exposure Factors Handbook: 2011 edition
[EPA Report], (EPA/600/R-090/052F). Washington, DC.
http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=236252. HERO ID: 786546
U.S. EPA. (U.S. Environmental Protection Agency). (2012a). Benchmark dose technical guidance.
(EPA/100/R-12/001). Washington, DC: U.S. Environmental Protection Agency, Risk Assessment
Forum, https://www.epa.gov/risk/benchmark-dose-technical-guidance. HERO ID: 1239433
U.S. EPA (U.S. Environmental Protection Agency). (2012b). Estimation Programs Interface Suite™ for
Microsoft® Windows, v 4.11. Washington, DC. https://www.epa.gov/tsca-screening-tools/epi-suitetm-
estimation-program-interface. HERO ID: 2347246
51

-------
U.S. EPA (U.S. Environmental Protection Agency). (2013). 1986-2002 inventory update reporting rule
data (non-confidential production volume in pounds). Washington, DC: Washington, DC. U.S.
Environmental Protection Agency, Office of Pollution Prevention and Toxics. HERO ID: 6114854
U.S. EPA. (U.S. Environmental Protection Agency). (2018a). Application of systematic review in TSCA
risk evaluations. (740-P1-8001). Washington, DC: U.S. Environmental Protection Agency, Office of
Chemical Safety and Pollution Prevention, https://www.epa.gov/sites/production/files/2018-
06/documents/final_application_of_sr_in_tsca_05-3l-18.pdf. HERO ID: 4532281
U.S. EPA (U.S. Environmental Protection Agency). (2018b). Basics of TRI reporting.
https://www.epa.gov/toxics-release-inventory-tri-program/basics-tri-reporting. HERO ID: 6181671
U.S. EPA (U.S. Environmental Protection Agency). (2018c). Hazardous Waste Management Facilities
and Units, https://www.epa.gov/hwpermitting/hazardous-waste-management-facilities-and-units. HERO
ID:5080427
U.S. EPA (U.S. Environmental Protection Agency). (2019a). Proposed designation of 1,1-
dichloroethane (CASRN 75-34-3) as a high-priority substance for risk evaluation. Washington, DC.
https://www.epa.gOv/sites/production/files/2019-08/documents/ll-dichloroethane_75-34-3_high-
priority_proposeddesignation_082319.pdf. HERO ID: 6305890
U.S. EPA (U.S. Environmental Protection Agency). (2019b). Chemical data reporting (2012 and 2016
non-CBI CDR database). Washington, DC.: Office of Pollution Prevention and Toxics. HERO ID:
6296234
USGS (U.S. Geological Survey). (1991a). USGS Monitoring Data: National Water Quality Monitoring
Council [Database], http://www.waterqualitydata.us/portal/. HERO ID: 4571753
USGS (U.S. Geological Survey). (1991b). USGS Monitoring Data: National Water Quality Monitoring
Council - Air.
https://www.waterqualitydata.us/portal/#siteType=f%20groundwater%20use&sampleMedia=Water&mi
meType=csv&dataProfile=activityAll. HERO ID: 6120444
USGS (U.S. Geological Survey). (1991c). USGS Monitoring Data: National Water Quality Monitoring
Council - Groundwater.
https://www.waterqualitydata.us/portal/#siteType=Aggregate%20groundwater%20use&sample
Media=Water&mimeType=csv&dataProfile=activityAll. HERO ID: 6120028
USGS (U.S. Geological Survey). (1991d). USGS Monitoring Data: National Water Quality Monitoring
Council - Sediment. https://www.waterqualitydata.us/portal/#sampleMedia=Sediment&mimeType=csv.
HERO ID: 6120597
USGS (U.S. Geological Survey). (1991e). USGS Monitoring Data: National Water Quality Monitoring
Council - Soil. https://www.waterqualitydata.us/portal/#sampleMedia=Soil&mimeType=csv. HERO ID:
6120844
USGS (U.S. Geological Survey). (1991f). USGS Monitoring Data: National Water Quality Monitoring
Council - Surface Water. https://www.waterqualitydata.us/portal/#siteType=Aggregate%20surface-
water-use&sampleMedia=Water&mimeType=csv. HERO ID: 6120448
52

-------
USGS (U.S. Geological Survey). (1991g). USGS Monitoring Data: National Water Quality Monitoring
Council - Tissue. https://www.waterqualitydata.us/portal/#sampleMedia=Tissue&mimeType=csv.
HERO ID: 6120843
Wood, PR;Lang, RF;Payan, IL. (1985). Anaerobic transformation, transport, and removal of volatile
chlorinated organics in ground water. In Ground Water Quality. New York, NY: John Wiley and Sons.
HERO ID: 4140343
53

-------
APPENDICES
Appendix A LIST OF GRAY LITERATURE SOURCES
Table Apx A-l. List of Gray Literature Sources for 1,1-Dichloroethane
Source/Agency
Source Name
Source Type
Source ('alegorv
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, II or III)
International
Resources
Assessment or Related
Document
CAL EPA
Technical Support Documents for
regulations: Cancer Potency
Information
Other US
Agency
Resources
Assessment or Related
Document
CAL EPA
Technical Support Documents for
regulations: Proposition 65, Cancer
Other US
Agency
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
European Union Risk Assessment
Report
International
Resources
Assessment or Related
Document
Env Canada
Chemicals at a Glance (fact sheets)
International
Resources
Assessment or Related
Document
EPA
Office of Water: STORET and WQX
US EPA
Resources
Database
EPA
Office of Air: AQS, Annual
US EPA
Resources
Database
54

-------
EPA
TSCA Hazard Characterizations
US EPA
Resources
Assessment or Related
Document
EPA
Included in 2011 NATA
US EPA
Resources
Assessment or Related
Document
EPA
Office of Air: National Emissions
Inventory (NEI) - National Emissions
Inventory (NEI) Data (2014, 2011,
2008)
US EPA
Resources
Database
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 Discharge Monitoring Report
Data
US EPA
Resources
Database
EPA
Office of Air: CFRs and Dockets
US EPA
Resources
Regulatory Document or List
KOECT
Kirk-Othmer Encyclopedia of
Chemical Technology Journal Article
Other
Resource
Encyclopedia
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
NIOSH
CDC NIOSH - Publications and
Products
Other US
Agency
Resources
Assessment or Related
Document
55

-------
NLM
National Library of Medicine's
HazMap
Other US
Agency
Resources
Database
NLM
National Library of Medicine's
PubChem
Other US
Agency
Resources
Database
NTP
Technical Reports
Other US
Agency
Resources
Assessment or Related
Document
NTP
Additional NTP Reports
Other US
Agency
Resources
Assessment or Related
Document
OECD
OECD Emission Scenario Documents
International
Resources
Assessment or Related
Document
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
RIVM Reports: Risk Assessments
International
Resources
Assessment or Related
Document
TERA
Toxicology Excellence for Risk
Assessment
Other
Resources
Assessment or Related
Document
56

-------
Appendix B PHYSICAL AND CHEMICAL PROPERTIES OF 1,1-
DICHLOROETHANE
This appendix provides p-chem information and data found in preliminary data gathering for 1,1-
dichloroethane. 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 1,1-Dichloroeiham fCASRN 75-34-3) as a
Hish-Prioritv Substance for Risk Evaluation (U.S. EPA (2019) 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.~H.< 1-2018-0426).
Table Apx B-l. Physical and Chemical Properties of 1,1-Dichloroethane	
Properly or Kmlpoinl
Value51
Reference
Dala Quality
K;i( in«
Molecular formula
C2H4CI2
NA
NA
Molecular weight
98.95 g/mol
NA
NA
Physical state
Liquid
NLM, 2018
High
Physical properties
Colorless, oily liquid,
ether-like odor
NLM, 2018
High
Melting point
-96.93°C
Rumble, 2018
High
Boiling point
57.4°C
NLM, 2018
High
Density
1.1680 g/cm3 at 25 °C
O'Neil, 2013
High
Vapor pressure
227 mm Hg at 25°C
NLM, 2018
High
Vapor density
3.44 (Air = 1)
NLM, 2018
High
Water solubility
5040 rng/L at 25°C
NLM, 2018
High
Log Octanol/water partition
coefficient (Log Kow)
1.79
NLM, 2018
High
Henry's Law constant
0.00562 atm-m Vmol
NLM, 2018
High
Flash point
-8.33°C (closed cup);
14°C (open cup)
NLM, 2018
High
57

-------
Propcrlv or Kmlpoinl
\ Slllll"1
Ucfcroncc
Dsilsi Qusililv
K;i( in«
Auto flammability
458°C
NLM, 2018
High
Viscosity
0.464 cP at 25 °C
Rumble, 2018
High
Refractive index
1.4164
Rumble, 2018
High
Dielectric constant
10.9
NLM, 2018
High
a Measured unless otherwise noted.
NA = Not applicable
58

-------
Appendix C ENVIRONMENTAL FATE AND TRANSPORT
PROPERTIES OF 1,1-DICHLOROETHANE
Table Apx C-l. Environmental Fate and Transport Properties of 1,1-Dichloroethane
Properly or Kndpoinl
Value
Reference
Direct Photodegradation
Not expected to be susceptible to direct
photolysis by sunlight because 1,1-
dichloroethane does not contain
chromophores that absorb at
wavelengths
>290 nm
HSDB (2018) citing Lyman et al
(1990)
Indirect Photodegradation
ti/2 = 39 days (based on 12-hour day;
1.5 x 106
•OH/cm3 from -OH rate constant of
2.74 x 10"13 cm3/molecule-second at 25
°C)
PhysProp Database (U.S. EPA.
2012c) citing Kwok and
Atkinson (1994)
Hydrolysis
ti/2 = 61.3 years at 25 °C and pH 7
HSDB (2018) citing Jeffers et al.
(1989)
Biodegradation
31. l%/25 days reductive
dechlorination to mainly chloroethane
(14.5%) in sludge (anaerobic water)
AT SDR (2015)

ti/2 >30-60 days (anaerobic soil)
AT SDR (2015); Wood et al.
(1985)

50%/7 days degradation and 19%/7
days evaporation at 5 ppm 1,1-
dichloroethane and 29%/7 days
degradation and 4%/7 days evaporation
at 10 ppm (aerobic static- screening-
flask test method with a municipal
wastewater sewage inoculum)
HSDB (2018) citing Tabak et al.
(1981)
Wastewater Treatment
72% total removal (9% by
biodegradation, 62% by volatilization
to air, 1% to sludge; estimated)13
U.S. EPA (2012b)
Bioconcentration Factor
7 (estimated)13
U.S. EPA (2012b)
Bioaccumulation Factor
6.8 (estimated)13
U.S. EPA (2012b)
Soil Organic Carbon:Water
Partition Coefficient (Log
Koc)
1.48
HSDB (2018) citing Sabljic et al.
(1995)
Notes: "Measured unless otherwise noted; bEPI Suite™ physical property inputs: Log Kow= 1.79, BP = 57.4 °C, MP
= -96.9 °C, VP = 227 mm Hg, WS = 5,040 mg/L, BioP = 120, BioA = 30 and BioS = 30, SMILES C(C1)(C1)C
¦OH = hydroxyl radical; OECD: Organisation for Economic Co-operation and Development; TG = test guideline; GC = gas
chromatography; MITI = Ministry of International Trade and Industry; BOD = biochemical oxygen demand; HPLC = high
performance liquid chromatography
59

-------
Appendix D REGULATORY HISTORY
The chemical substance, 1,1-dichloroethane, is subject to federal and state laws and regulations in the
United States (TableApx D-l and TableApx D-2). Regulatory actions by other governments, tribes
and international agreements applicable to 1,1-dichloroethane are listed in Table Apx D-3.
Table Apx D-l. Federal Laws and Regulations
Mat ulcs/Uegulal ions
Description of Aiilhorily/Ucgulation
Description of Regulation
U'A 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.
1,1-Dichloroethane is one of the 20
chemicals EPA designated as a
High-Priority Substance for risk
evaluation under TSCA (84 FR
24, December 30, 2019).
Designation of 1,1-Dichloroethane
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.
1,1 -Dichloroethane 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(e)
Manufacturers (including importers),
processors, and distributors must
immediately notify EPA if they obtain
information that supports the conclusion
that a chemical substance or mixture
presents a substantial risk of injury to
health or the environment.
One risk report was received for 1,1-
Dichloroethane (1993) (U.S. EPA,
ChemView. Accessed April 3,
2019).
Toxic Substances
Control Act (TSCA)
- Section 4
Provides EPA with authority to issue
rules and orders requiring manufacturers
(including importers) and processors to
test chemical substances and mixtures.
One chemical data submission from
test rules was received for 1,1-
Dichloroethane: Hydrolysis Study.
(Chemical Test Rule Data - 1988)
(U.S. EPA, ChemView. Accessed
April 11, 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
1,1 -Dichloroethane (Ethylidene
Dichloride) is a listed substance
subject to reporting requirements
under 40 CFR 372.65 effective as of
1/1/1994.
60

-------
Msiliilcs/Ucgiihilions
Description of Aiilhorily/Ucgiihition
Description of Requisition

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).

Clean Air Act (CAA)
- Section 112(b)
Defines the original list of 189 hazardous air
pollutants (HAPs). Under 112(c) of the
CAA, EPA must identify and list source
categories that emit HAP and then set
emission standards for those listed source
categories under CAA section 112(d). CAA
section 112(b)(3)(A) specifies that any
person may petition the Administrator to
modify the list of HAP by adding or deleting
a substance. Since 1990, EPA has removed
two pollutants from the original list leaving
187 at present.
1,1-Dichloroethane is listed as a HAP
(42 U.S. Code section 7412).
Clean Air Act (CAA)
- Section 112(d)
Directs EPA to establish, by rule, NESHAPs
for each category or subcategory of listed
major sources and area sources of HAPs
(listed pursuant to Section 112(c)). For
major sources, the standards must require
the maximum degree of emission reduction
that EPA determines is achievable by each
particular source category. This is generally
referred to as maximum achievable control
technology (MACT). For area sources, the
standards must require generally achievable
control technology (GACT) though may
require MACT.
EPA has established NESHAPs for a
number of source categories that emit
1,1-Dichloroethane to air. (See
httDs://www.eDa.20v/stationarv-sources-
air-pollution/national-emission-
standards-hazardous-air-pollutants-
neshaD-9)
Clean Water Act
(CWA) - Section 301,
304, 306, 307, and 402
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
A. These are pollutants for which best
available technology effluent limitations
must be established on either a national
1,1-Dichloroethane is designated as a
priority pollutant under section
307(a)(1) of the CWA and as such is
subject to effluent limitations.
Under CWA section 304, 1,1-
Dichloroethane is included in the list
of total toxic organics (TTO) (40
CFR 413.02(i)).
61

-------
Msiliilcs/Ucgiihilions
Description of Aiilhorily/Ucgiihition
Description of Requisition

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.

Safe Drinking Water
Act (SDWA) - Section
1412(b)
Every 5 years, EPA must publish a list of
contaminants that: (1) are currently
unregulated, (2) are known or anticipated to
occur in public water systems (PWSs) and
(3) may require regulations under SDWA.
EPA must also determine whether to
regulate at least five contaminants from the
list every 5 years.
1, 1-Dichloroethane was identified
on CCL1 (1998), CCL2 (2005),
CCL3 (2016), and CCL4 (2016).
Contaminant Candidate List (CCL)
63 FR 10274, March 2, 1998, 70 FR
9071, February 24.2005, 81 FR 1,
January 4, 2016, 81 FR 81099,
November 17, 2016.
Safe Drinking Water
Act (SDWA) - Section
1445(a)
Every 5 years, EPA must issue a new list of
no more than 30 unregulated contaminants
to be monitored by PWSs. The data obtained
must be entered into the National Drinking
Water Contaminant Occurrence Database.
1,1-Dichloroethane was identified in
the third Unregulated Contaminant
Monitoring Rule (UCMR3), issued
in 2012 (77 FR 26071, May 2, 2012).
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.
1,1-Dichloroethane is included on the
list of hazardous wastes pursuant to
RCRA 3001.
RCRA Hazardous Waste Code: U076
(40 CFR 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.
1,1-Dichloroethane is a hazardous
substance under CERCLA. Releases of
1,1-Dichloroethane in excess of 1000
pounds must be reported (40 CFR
302.4).
62

-------
MsiliiU's/Ucguhilions
Description of Aiilhorily/Ucgiihilion
Description of Ucgiihition

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.

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.
1,1-Dichloroethane 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.
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.
In 1993, OSHA issued occupational
safety and health standards for 1,1-
Dichloroethane that included a PEL of
100 ppm TWA, exposure monitoring,
control measures and respiratory
protection (29 CFR 1910.1000).
OSHA Annotated Table Z-l, Accessed
April 16, 2019.
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.
1,1-Dichloroethane 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).
63

-------
Mat ulcs/Uegulal ions
Description of Aiilhorily/Ucgulation
Description of Regulation
Department of Energy
Protective Action Criteria
PAC listed for 1,1-Dichloroethane.
D.l State Laws and Regulations
Table Apx D-2. State Laws and Regulations
State Actions
Description of Action
State Air Regulations
Allowable Ambient Levels: New Hampshire 2037 24-Hr AAL (|ig/m3) 1358 Annual
AALB (|ig/m3 ) (Env-A 1400: Regulated Toxic Air Pollutants). Rhode Island 0.6
Annual (|ig/m3 ) (Air Pollution Regulation No. 22).
State Drinking Water
Standards and Guidelines
California (Cal Code Regs. Title 26, § 22-64444), Connecticut - **A MCL has not
been established forthis chemical (Conn. Agencies Regs. § 19-13-B102), Florida
(Fla. Admin. Code R. Chap. 62-550), Massachusetts (310 Code Mass. Regs. §
22.00), Michigan (Mich. Admin. Code r.299.44 and r.299.49, 2017), Minnesota
(Minn R. Chap. 4720), New Jersey (7:10 N.J Admin. Code § 5.2).
State Water Pollution
Discharge Programs
Illinois has adopted water pollution discharge programs which categorize 1,1-
dichloroethane as an "halogenated organic chemical," as applicable to the process
wastewater discharges resulting from the manufacture of bulk organic chemicals (35
111. Adm. Code 307-2406).
State PELs
California (PEL of 110 ppm (Cal Code Regs. Title 8, § 5155)
iawaii PEL: 100 ppm (Hawaii Administrative Rules section 12-60-50).
State Right-to-Know Acts
Massachusetts (105 Code Mass. Regs. § 670.000 Appendix A), New Jersey
(N.J.A.C. 7:1G) and Pennsylvania (P.L. 734, No. 159 and 34 Pa. Code § 323).
Chemicals of High
Concern to Children
Several states have adopted reporting laws for chemicals in children's
products containing 1,1-Dichloroethane, including Maine (38 MRS A Chapter
16-D), Minnesota (Toxic Free Kids Act Minn. Stat. 116.9401 to 116.9407).
Other
California listed 1,1-Dichloroethane on Proposition 65 in 1990 due to cancer
risk (Cal Code Regs. Title 27, § 27001).
1,1-Dichloroethane is listed as a Candidate Chemical under California's Safer
Consumer Products Program established under Health and Safety Code §
25252 and 25253 (California, Candidate Chemicals List. Accessed April 18,
2019) (CDTSC, 2017).
California lists 1,1-Dichloroethane as a designated priority chemical for
biomonitoring under criteria established by California SB 1379 (CDPH,
2015) (Accessed February 2019).
1,1-Dichloroethane is on the MA Toxic Use Reduction Act (TURA) list of
1994 (301 Code Mass. Regs. § 41.03).
64

-------
D.2 International Laws and Regulations
Tahle_Apx D-3. Regulato
Country/Tribe/
Organization
rv Actions hv other Governments. Tribes, and International Agreements
Requirements and Restrictions
Canada
Canada requires notification for 1,1-Dichloroethane under the New Substances
Notification Regulations (Chemicals and Polymers) so that health and ecological
risks can be assessed before the substance is manufactured or imported into
Canada above threshold quantities, however they are subject to fewer information
requirements. Canada Gazette Part I, Vol. 142, No. 25, June 21, 2008.
European Union
Not registered in the EU
Accessed April 17, 2019.
Australia
1,1-Dichloroethane can be manufactured or imported into Australia for commercial
purposes without notifying the Australian government, provided that the Australian
importer/manufacturer is currently registered with the Australian government.
1,1-Dichloroethane was assessed under Human Health Tier II of the Inventory
Multi-Tiered Assessment and Prioritisation (IMAP). No specific Australian use,
import, or manufacturing information has been identified. (NICNAS, 2017,
Ethane, 1,1-dichloro-: Human health tier II assessment Accessed April 17,
2019/
Japan
1,1-Dichloroethane is regulated in Japan under the following legislation:
Act on the Evaluation of Chemical Substances and Regulation of Their
Manufacture, etc. (Chemical Substances Control Law; CSCL)
Industrial Safety and Health Act (ISHA)
(National Institute of Technology and Evaluation [NITE] Chemical Risk
Information Platform [CHRIP]). (Accessed April 17, 2019).
Australia, Austria, Belgium,
Canada, Denmark,
European Union, Finland,
France, Germany, Hungary,
Ireland, Italy, Japan, Latvia
New Zealand, Poland,
Romania, Singapore, South
Korea, Spain, Sweden,
Switzerland, The
Netherlands, Turkey,
United Kingdom
Occupational exposure limits for 1,1-Dichloroethane (GESTIS International limit
values for chemical agents (Occupational exposure limits, OELs) database).
(Accessed April 18, 2019).
65

-------
Appendix E PROCESS, RELEASE AND OCCUPATIONAL
EXPOSURE INFORMATION
This appendix provides information and data found in preliminary data gathering for 1,1-dichloroethane.
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)
E.l.1.1 Manufacture
Various methods for manufacture of 1,1-Dichloroethane are discussed in the literature. 1,1-
Dichloroethane may be produced by chlorination of ethane or chloroethane, via thermal chlorination,
photochlorination, or oxychlorination. Alternatively, 1,1-Dichloroethane can be produced by adding
hydrogen chloride to acetylene (Dreher, et al., 2014). In the 2016 CDR, one company reported
manufacturing 1,1-Dichloroethane (U.S. EPA, 2016).
E.l.1.2 Import
Commodity chemicals such as 1,1-Dichloroethane may be imported into the United States in bulk via
water, air, land, and intermodal shipments (Tomer, 2015). These shipments take the form of oceangoing
chemical tankers, railcars, tank trucks, and intermodal tank containers. Chemicals shipped in bulk
containers may be repackaged into smaller containers for resale, such as drums or bottles. Domestically
manufactured commodity chemicals may be shipped within the United States in liquid cargo barges,
railcars, tank trucks, tank containers, intermediate bulk containers (IBCs)/totes, and drums. 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.
1,1-Dichloroethane may be imported neat or as a component in a formulation. In the 2016 CDR, no
companies reported importing 1,1-Dichloroethane.
E.1.2 Processing and Distribution
E.l.2.1 Processing as a Reactant or Intermediate
Processing as a reactant or intermediate is the use of 1,1-Dichloroethane as a feedstock in the production
of another chemical via a chemical reaction in which 1,1-Dichloroethane is consumed to form the
product. In the 2016 CDR, companies reported use of 1,1-Dichloroethane as an intermediate in the
manufacture of basic organic chemicals and other chemical products. EPA has not identified specific
process information for the processing of 1,1-Dichloroethane as a reactant but will further investigate
during the risk evaluation (U.S. EPA, 2016).
66

-------
E. 1.2.2 Recycling
EPA did not identify 1,1-dichloroethane specific information for recycling; however, a general
description of waste solvent recovery processes was identified. Waste solvents are generated when the
solvent stream becomes contaminated with suspended and dissolved solids, organics, water or other
substance. Waste solvents can be restored to a condition that permits reuse via solvent
reclamation/recycling (U.S. EPA, 1980a).
E.1.3 Uses
E.l.3.1 Laboratory Use
Sources indicate 1,1-Dichloroethane use as laboratory reference standard (SigmaAldrich, undated;
Restek, 2020). EPA plans to further investigate the specific laboratory use activities of 1,1-
Dichloroethane during the risk evaluation.
E.1.4 Disposal
Each of the conditions of use of 1,1-dichloroethane 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 will be assessed in each condition of use
assessment. Wastes of 1,1-dichloroethane 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: 1,1-dichloroethane may be contained in wastewater discharged to POTW or other,
non-public treatment works for treatment. Industrial wastewater containing 1,1-dichloroethane
discharged to a POTW may be subject to EPA or authorized NPDES state pretreatment
programs.
•	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 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.
1,1-Dichloroethane is a U-listed hazardous waste under code U076 under RCRA; therefore,
discarded, unused pure and commercial grades of 1,1-dichloroethane are regulated as a
hazardous waste under RCRA (40 CFR § 261.33(f)).
•	Wastes Exempted as Solid Wastes under RCRA: Certain conditions of use of 1,1-dichloroethane
may generate wastes of 1,1-dichloroethane that are exempted as solid wastes under 40 CFR §
261.4(a). For example, the generation and legitimate reclamation of hazardous secondary
materials of 1,1-dichloroethane may be exempt as a solid waste.
67

-------
E.2 Sources Containing Potentially Relevant Data or Information
EPA presents below examples of occupational exposure-related information from the preliminary data
gathering. EPA plans to consider this information and data in combination of other data and methods for
use in the risk evaluation. Note there are no OSHA Chemical Exposure and Health Data (CEHD) or
NIOSH Health Hazard Evaluations for 1,1-dichloroethane within the last ten years.
TableApx E-l. Summary of Industry Sectors with 1,1-Dichloroethane Personal Monitoring Air
Samples Obtained from OSHA Inspections Conducted since 1984
SIC
Code
SIC Description
Number of
Data Points
1731
Electrical Work
4
3559
Special Industry Machinery, Not Elsewhere Classified
1
3842
Orthopedic, Prosthetic, and Surgical Appliances and Supplies
3
4212
Local Trucking Without Storage
15
8351
Child Day Care Services
1
Table Apx E-2. Potentially Relevant Data Sources for Exposure Monitoring and Area Monitoring
Data from NIOSH Health Hazard Evaluations
Year of
Publication
Report Number
I'acility Description
1992
HETA 91-251-2218
Manufacture of self-lubricating ball bearings
68

-------
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 Su
jporting Table
I.il'c ( \ck- S(;i»c
C.iU'Sion
Siihciileiion
Kok'iiso/r.\|)osuiv
Scen;iri»
I'1\|)osiiiv
PiKliwin
r.\|)(isuiv
Koulo
Km'plor
Phins lo
I'\ ;i In ;i lo
Kiilioiiiilo
Manufacturing
Domestic
manufacturing
Domestic
manufacturing
Manufacture of 1,1-
Dichloroethane
Liquid
Contact
Dermal
Worker
Yes
Workers are expected to
routinely handle liquids
containing 1, 1-dichloroethane
Vapor
Inhalation
Worker
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.
Liquid
Contact
Dermal
ONU
No
Dermal exposure by ONU is
not expected for this condition
of use as they arc not
expected to directly handle
the chemical.
Vapor
Inhalation
ONU
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.
69

-------
l.il'c ( \clc S(;i»c
C.iU'fion
SiiIk*;i Ir^on
Uok'iisc/r.\|)osiiiv
Smiiirio
Mxposuiv
PiKhwin
l'l\|)OMIIV
Koulc
Km'plor
I'lilllS lo
l'.\iiliiiiH*
Kiilioiiiilo
Processing
As a reactant
Intermediate in
all other basic
organic chemical
Processing of organic
and other chemical
products
Liquid
Contact
Dermal
Worker
Yes
Workers are expected to
routinely handle liquids
containing I, 1-dichloroethane


manufacturing

Vapor
Inhalation
Worker
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.


Intermediate in
all other chemical
product and
preparation
manufacturing

Liquid
Contact
Dermal
ONU
No
Dermal exposure by ONU is
not expected for this condition
of use as they arc not
expected to directly handle
the chemical.




Vapor
Inhalation
ONU
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.

Recycling
Recycling
Recycling 1,1-
dichloroethane
Liquid
Contact
Dermal
Worker
Yes
Workers are expected to
routinely handle liquids
containing I, 1-dichloroethane




Vapor
Inhalation
Worker
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.




Liquid
Contact
Dermal
ONU
No
Dermal exposure by ONU is
not expected for this condition
of use as they are not
expected to directly handle
the chemical.




Vapor
Inhalation
ONU
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.
70

-------
l.il'c ( \clc S(;i»c
C.iU'fion
SiiIk*;i Ir^on
Uok'iisc/r.\|)osiiiv
Smiiirio
Mxposuiv
PiKhwin
l'l\|)OMIIV
Koulo
Km'plor
I'lilllS lo
l.\iiliiiiH*
Kiilioiiiilo
Distribution in
Commerce
Distribution in
commerce
Distribution in
commerce
Distribution of bulk
shipments of 1,1-
dichloroethane and
formulated products
Liquid
Contact,
Vapor
Dermal,
Inhalation
Worker, ONU
Yes
EPA plans to analyze
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, disposal)
rather than as a single
distribution scenario.
Commercial Use
Other use
Laboratory and
Analytical Uses
Exposures occuring
during; Laboratory
and Analytical Uses
Liquid
Contact
Dermal
Worker
Yes
Workers are expected to
routinely handle liquids
containing 1, 1-dichloroethane




Vapor
Inhalation
Worker
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.




Liquid
Contact
Dermal
ONU
No
Dermal exposure by ONU is
not expected for this condition
of use as they are not
expected to directly handle
the chemical.




Vapor
Inhalation
ONU
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.
71

-------
l.il'c ( \clc S(;i»c
C.iU'fion
SiiIk*;i Ir^on
Uok'iisc/r.\|)osiiiv
Smiiirio
Mxposuiv
PiKhwin
I'1\|)osiiiv
Koulo
Km'plor
Phins lo
l'.\illllilH*
Kiilioiiiilo
Disposal
Disposal
Waste Handling,
Treatment, and
Disposal
Exposures occuring
during; disposal
Liquid
Contact
Dermal
Worker
Yes
Workers are expected to
routinely handle liquids
containing 1, 1-dichloroethane




Vapor
Inhalation
Worker
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.




Liquid
Contact
Dermal
ONU
No
Dermal exposure by ONU is
not expected for this condition
of use as they arc not
expected to directly handle
the chemical.




Vapor
Inhalation
ONU
Yes
Due to high volatility (230
mmHg at 25C), EPA plans to
evaluate inhalation exposure
to vapor.
72

-------
Appendix G SUPPORTING INFORMATION - CONCEPTUAL MODEL FOR
ENVIRONMENTAL RELEASES AND WASTES
Table Apx G-l. General Population and Environmental Exposure Conceptual Model Supporting Table
1 .i IV
Cu-le
S(ii»e

Kok'iiso
r.xpnsurc'
Piilhwin / Modiii
l-lxposmv Routes
Km'plor/
Population
I'lilllS lo
Kiilioiiiilo



Near laeilil>
anihieni air
concent radons
Inhalation
(leneral Kipiilalion
\n


1 Emissions lo \ 11"
1 Emissions lo \11"
11 id i reel
depusiiiiin iii
nearln bodies of
ualerand sml
ealelinieiiis
()r;il. Dermal
(leneral Kipiilalion
\n
1.1 -1 )ieliliii'iielliane is a
MM' 1 iecanse sialiiinais
siuiiee releases of 1.1 -
dieliliii'iielliane lo anihieni
air are nnder ilie ini'isdielinii
nl'llie ( \ \



II !l)
\qnalie and
1 eiresiiial
keeepinis
\n

All








Wastewater or Liquid
Wastes
Industrial pre-
treatment and
wastewater
Direct release
into surface water
and indirect
partitioning to
sediment
TBD
Aquatic and
Terrestrial
Receptors
Yes
This chemical is expected to
be released to surface water

treatment, or POTW
Direct release
into surface water
and partitioning
to sediment and
bioaccumulation
into edible
aquatic species
Oral
Inhalation
General Population
Yes
11 The exposure pathways, exposure routes and hazards 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 1,1-dichloroethane in exposure pathways falling under the jurisdiction of these EPA statutes.
73

-------
1 .i IV
< \cle
S(ii»c
( 'silcgorics
Ki'k'sisi*
l'l\|)OMIIV
PiKhwin / Modiii
I'lxposiiiv Routes
Receptor/
Population
I'lilllS (o
l.\aluak'"
Kiilioiiiilc



1 )riiikinu Waler
\ la Sin lace or
(iioiiiid Waler
()ral
Dermal and
Inhalation (e u
showcriimi
(icncral I'opiilaliou
\o
The driiikinu waler
e\posiire palhwas lor 1.1-
dichloroelhaiie is ciirreniK
addressed mi the Sl)\\ \
remilaloi'\ anal>lical process
lor public waler s\ sienis.



Biosolids:
application to soil
Oral (e.g. ingestion
of soil)
Inhalation
General Population
Yes
Although 1,1-
dichloroethane is a volatile
chemical and not expected
to sorb onto biosolids, EPA



and/or migration
to groundwater
and/or surface
water
TBD
Terrestrial
receptors
Yes
plans to analyze this
pathway. However, it is
expected to be a minor
pathway of exposure to the
general population and
terrestrial species.


U ndcrground
injection
Migration to
groundwater.
Oral
Dermal
Inhalation
General Population
No
1.1-dichloroelhanc is
released to Class I


potential
surface/drinking
water
TBD
Aquatic and
Terrestrial
Receptors
No
Undcrground Injection
Wells which are covered by
SDWA and RCRA.

Solid and Liquid
Wastes
Hazardous.
Municipal landfill
and other land
disposal
Lcachalc to soil,
ground water
and/or mitigation
to surface water
Oral (e.g., ingestion)
Dermal
Inhalation
General Population
No
1.1 -di.chloroctha.nc is
included on the list of

TBD
Aquatic and
Terrestrial
Receptors
No
hazardous wastes pursuant
to RCRA 3001 (40 CFR JJJj
261.33).
74

-------