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5 UNREASONABLE RISK DETERMINATION
TSCA section 6(b)(4) requires EPA to conduct a risk evaluation to determine whether a chemical
substance presents an unreasonable risk of injury to health or the environment, without
consideration of costs or other nonrisk factors, including an unreasonable risk to a potentially
exposed or susceptible subpopulation identified by EPA as relevant to this Risk Evaluation,
under the conditions of use.
EPA has determined that methylene chloride presents an unreasonable risk of injury to health
under the conditions of use. This determination is based on the information in previous sections
of this Risk Evaluation, the appendices and supporting documents of methylene chloride, in
accordance with TSCA section 6(b), as well as TSCA's best available science (TSCA section
26(h)) and weight of scientific evidence standards (TSCA section 26(i)), and relevant
implementing regulations in 40 CFR part 702.
The full list of conditions of use evaluated for methylene chloride are listed in Table 1-4 of this
Risk Evaluation (Ref. 1). EPA's unreasonable risk determination for methylene chloride is
driven by risks associated with the following conditions of use, considered singularly or in
combination with other exposures:
• Manufacturing (Domestic Manufacture)
• Manufacturing (Import)
• Processing: as a reactant
• Processing: incorporation into a formulation, mixture, or reaction products
• Processing: repackaging
• Processing: recycling
• Industrial and commercial use as
• Industrial and commercial use as
• Industrial and commercial use as
• Industrial and commercial use as
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
• Industrial and commercial use in
conditioners)
solvent for batch vapor degreasing
solvent for in-line vapor degreasing
solvent for cold cleaning
solvent for aerosol spray degreaser/cleaner
adhesives, sealants and caulks
paints and coatings
paint and coating removers
adhesive and caulk removers
metal aerosol degreasers
metal non-aerosol degreasers
finishing products for fabric, textiles and leather
automotive care products (functional fluids for air
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• Industrial and commercial use in automotive care products (interior car care)
• Industrial and commercial use in automotive care products (degreasers)
• Industrial and commercial use in apparel and footwear care products
• Industrial and commercial use in spot removers for apparel and textiles
• Industrial and commercial use in liquid lubricants and greases
• Industrial and commercial use in spray lubricants and greases
• Industrial and commercial use in aerosol degreasers and cleaners
• Industrial and commercial use in non-aerosol degreasers and cleaners
• Industrial and commercial use in cold pipe insulations
• Industrial and commercial use as solvent that becomes part of a formulation or mixture
• Industrial and commercial use as a processing aid
• Industrial and commercial use as propellant and blowing agent
• Industrial and commercial use for electrical equipment, appliance, and component
manufacturing
• Industrial and commercial use for plastic and rubber products manufacturing
• Industrial and commercial use in cellulose triacetate film production
• Industrial and commercial use as anti-spatter welding aerosol
• Industrial and commercial use for oil and gas drilling, extraction, and support activities
• Industrial and commercial use in toys, playground and sporting equipment
• Industrial and commercial use in lithographic printing plate cleaner
• Industrial and commercial use in carbon remover, wood floor cleaner, and brush cleaner
• Industrial and commercial use as laboratory chemical
• Consumer use as solvent in aerosol degreasers/cleaners
• Consumer use in adhesives and sealants
• Consumer use in brush cleaners for paints and coatings
• Consumer use adhesive and caulk removers
• Consumer use in metal degreasers
• Consumer use in automotive care products (functional fluids for air conditioners)
• Consumer use in automotive care products (degreasers)
• Consumer use in lubricants and greases
• Consumer use in cold pipe insulation
• Consumer use in arts, crafts, and hobby materials glue
• Consumer use in an anti-spatter welding aerosol
• Consumer use in carbon removers and other brush cleaners
• Disposal
The following condition of use does not drive EPA's unreasonable risk determination for
methylene chloride:
• Distribution in commerce
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EPA is not making a condition of use-specific risk determination for this condition of use, is not
issuing a final order under TSCA section 6(i)(l) for this condition of use, and does not consider
the revised risk determination for methylene chloride to constitute a final agency action at this
point in time.
Consistent with the statutory requirements of TSCA section 6(a), EPA will propose risk
management regulatory action to the extent necessary so that methylene chloride no longer
presents an unreasonable risk. EPA expects to focus its risk management action on the conditions
of use that drive the unreasonable risk. However, it should be noted that, under TSCA section
6(a), EPA is not limited to regulating the specific activities found to drive unreasonable risk and
may select from among a suite of risk management requirements in section 6(a) related to
manufacture (including import), processing, distribution in commerce, commercial use, and
disposal as part of its regulatory options to address the unreasonable risk. As a general example,
EPA may regulate upstream activities (e.g., processing, distribution in commerce) to address
downstream activities (e.g., consumer uses) driving unreasonable risk, even if the upstream
activities do not drive the unreasonable risk.
5.1 Background
5.1.1 Background on Policy Changes Relating to the Whole Chemical Risk
Determination and Assumption of PPE Use by Workers
From June 2020 to January 2021, EPA published risk evaluations on the first ten chemical
substances, including for methylene chloride. The risk evaluations included individual
unreasonable risk determinations for each condition of use evaluated. The determinations that
particular conditions of use did not present an unreasonable risk were issued by order under
TSCA section 6(i)(l).
In accordance with Executive Order 13990 ("Protecting Public Health and the Environment and
Restoring Science to Tackle the Climate Crisis") and other Administration priorities (Refs. 2, 3,
4, and 5), EPA reviewed the risk evaluations for the first ten chemical substances to ensure that
they meet the requirements of TSCA, including conducting decision-making in a manner that is
consistent with the best available science and weight of the scientific evidence.
As a result of this review, EPA announced plans to revise specific aspects of certain of the first
ten risk evaluations in order to ensure that the risk evaluations appropriately identify
unreasonable risks and thereby can help ensure the protection of health and the environment
(Ref. 6). To that end, EPA has reconsidered two key aspects of the risk determinations for
methylene chloride published in June 2020. First, EPA has determined that the appropriate
approach to these determinations is to make an unreasonable risk determination for methylene
chloride as a whole chemical substance, rather than making unreasonable risk determinations
separately on each individual condition of use evaluated in the risk evaluation. Second, EPA has
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determined that the risk determination explicitly state that it does not rely on assumptions
regarding the use of personal protective equipment (PPE) in making the unreasonable risk
determination under TSCA section 6; rather, the use of PPE will be considered during risk
management. Making unreasonable risk determinations based on the baseline scenario without
assuming PPE should not be viewed as an indication that EPA believes there are no occupational
safety protections in place at any location or that there is widespread noncompliance with
applicable OSHA standards. EPA understands that there could be occupational safety protections
in place at workplace locations; however, not assuming use of PPE reflects EPA's recognition
that unreasonable risk may exist for subpopulations of workers that may be highly exposed
because they are not covered by OSHA standards, or their employers are out of compliance with
OSHA standards, or because many of OSHA's chemical-specific permissible exposure limits
largely adopted in the 1970's are described by OSHA as being "outdated and inadequate for
ensuring protection of worker health,"1 or because the OSHA Permissible Exposure Limit may
be inadequate for ensuring protection of worker health, or because EPA finds unreasonable risk
for purposes of TSCA notwithstanding OSHA requirements.
Separately, EPA is conducting a screening approach to assess potential risks from the air and
water pathways for several of the first 10 chemicals, including this chemical. For methylene
chloride the exposure pathways that were or could be regulated under another EPA-administered
statute were excluded from the final risk evaluation (see section 1.4.2 of the June 2020
methylene chloride risk evaluation). This resulted in the surface water, drinking water, and
ambient air pathways for methylene chloride not being assessed for human health exposures or
the general population. The goal of the recently-developed screening approach is to remedy this
exclusion and to identify if there are risks that were unaccounted for in the methylene chloride
risk evaluation. The screening-level approach has gone through public comment and independent
external peer review through the SACC. The Agency received the final peer review report on
May 18, 2022, and has reviewed public comments and SACC comments. EPA expects to
describe its findings regarding the chemical-specific application of this screening-level approach
in the forthcoming proposed rule under TSCA section 6(a) for methylene chloride.
Further discussion of the rationale for the whole chemical approach is found in the Federal
Register Notice in the docket accompanying this revised methylene chloride unreasonable risk
determination and further discussion of the decision to not rely on assumptions regarding the use
of PPE is provided in the Federal Register Notice and in Section 5.2.4 below. With respect to the
methylene chloride risk evaluation, EPA did not amend, nor does a whole chemical approach or
change in assumptions regarding PPE require amending, the underlying scientific analysis of the
risk evaluation in the risk characterization section of the risk evaluation.
1 As noted on OSHA's Annotated Table of Permissible Exposure Limits: "OSHA recognizes that many of its
permissible exposure limits (PELs) are outdated and inadequate for ensuring protection of worker health. Most of
OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970, and
have not been updated since that time" (Ref. 7).
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With regard to the specific circumstances of methylene chloride, as further explained below,
EPA has determined that a whole chemical approach is appropriate in order to protect health and
the environment. The whole chemical approach is appropriate for methylene chloride because
there are benchmark exceedances for multiple conditions of use (spanning across most aspects of
the chemical lifecycle-from manufacturing (including import), processing, commercial and
consumer use, and disposal) for human health and the health effects associated with methylene
chloride exposures are irreversible. Because these chemical-specific properties cut across the
conditions of use within the scope of the risk evaluation, and a substantial amount of the
conditions of use drive the unreasonable risk, it is therefore appropriate for the Agency to make a
determination that the whole chemical presents an unreasonable risk. In addition, as discussed
below in Section 5.2.4, in making this risk determination, EPA believes it is appropriate to
evaluate the levels of risk present in baseline scenarios where PPE is not assumed to be used by
workers. EPA is revising the assumption for methylene chloride that workers always and
properly use PPE, although it does not question the public comments received regarding the
occupational safety practices often followed by industry respondents.
As explained in the Federal Register Notice, the revisions to the unreasonable risk determination
(Section 5 of this Risk Evaluation) follow the issuance of a draft revision to the TSCA methylene
chloride unreasonable risk determination (87 FR 39824, July 5, 2022) (Ref. 8) and the receipt of
public comment. A response to comments document is also being issued with this final revised
unreasonable risk determination for methylene chloride (Ref. 9). As noted in the Federal Register
Notice, the revisions to the unreasonable risk determination are based on the existing risk
characterization section of this Risk Evaluation (Section 4), and do not involve additional
technical or scientific analysis. The discussion of the issues in this revision to the risk
determination supersedes any conflicting statements in the prior methylene chloride risk
evaluation (June 2020) and the response to comments document (Summary of External Peer
Review and Public Comments and Disposition for Methylene Chloride (MC), June 2020). EPA
also views the peer reviewed hazard and exposure assessments and associated risk
characterization as robust and upholding the standards of best available science and weight of the
scientific evidence, per TSCA sections 26(h) and (i).
5.1.2 Background on Unreasonable Risk Determination
In each risk evaluation under TSCA section 6(b), EPA determines whether a chemical substance
presents an unreasonable risk of injury to health or the environment, under the conditions of use.
The unreasonable risk determination does not consider costs or other nonrisk factors. In making
the unreasonable risk determination, EPA considers relevant risk-related factors, including, but
not limited to: the effects of the chemical substance on health and human exposure to such
substance under the conditions of use (including cancer and non-cancer risks); the effects of the
chemical substance on the environment and environmental exposure under the conditions of use;
the population exposed (including any potentially exposed or susceptible subpopulations
(PESS)); the severity of hazard (including the nature of the hazard, the irreversibility of the
hazard); and uncertainties. EPA also takes into consideration the Agency's confidence in the data
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used in the risk estimate. This includes an evaluation of the strengths, limitations, and
uncertainties associated with the information used to inform the risk estimate and the risk
characterization. This approach is in keeping with the Agency's final rule, Procedures for
Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (82 FR 3 3 726, July
20, 2017).2
This section describes the revised unreasonable risk determination for methylene chloride, under
the conditions of use in the scope of the Risk Evaluation for methylene chloride. This revised
unreasonable risk determination is based on the risk estimates in the final Risk Evaluation, which
may differ from the risk estimates in the draft Risk Evaluation due to peer review and public
comments.
5.2 Unreasonable Risk to Human Health
5.2.1 Human Health
EPA's methylene chloride Risk Evaluation identified non-cancer adverse effects from acute and
chronic inhalation and dermal exposures to methylene chloride, and cancer from chronic
inhalation and dermal exposures to methylene chloride. In the methylene chloride risk
characterization, neurotoxicity effects (CNS depression) were identified as the most sensitive
endpoint for non-cancer adverse effect from acute inhalation, and dermal exposures, and liver
effects were identified as the most sensitive endpoint for non-cancer adverse effects from chronic
inhalation and dermal exposures for all conditions of use. Additional risks associated with other
adverse effects (e.g., other nervous system effects, immune system effects; reproductive and
developmental effects; and irritation/burns) were identified for acute and chronic exposures. The
health risk estimates for all conditions of use are in Tables 4-2 of Section 4.1.2 of this Risk
Evaluation.
In developing the exposure assessment for methylene chloride, EPA identified the following
groups as Potentially Exposed or Susceptible Subpopulations (PESS): workers and occupational
non-users (ONUs)3 (including men and women of reproductive age, and adolescents); consumer
users and bystanders (of any age group, including infants, toddlers, children, and elderly)
(Section 2.4.1 and Tables 4-2 and 4-3 of this Risk Evaluation).
EPA evaluated exposures to workers, ONUs, consumer users, and bystanders using reasonably
available monitoring and modeling data for inhalation and dermal exposures as applicable. For
example, EPA assumed that ONUs and bystanders do not have direct contact with methylene
chloride; therefore, non-cancer effects and cancer from dermal exposures to methylene chloride
2 This risk determination is being issued under TSCA section 6(b) and the terms used, such as unreasonable risk, and
the considerations discussed are specific to TSCA. Other EPA programs have different statutory authorities and
mandates and may involve risk considerations other than those discussed here.
3 ONUs are workers who do not directly handle methylene chloride but perform work in an area where methylene
chloride is present. (Executive Summary of this Risk Evaluation).
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were not evaluated. The description of the data used for human health exposure is in Section 2.4
of this Risk Evaluation. Uncertainties in the analysis are discussed in Section 4.4 of this Risk
Evaluation and are considered in the unreasonable risk determination, including the fact that the
dermal model used for occupational exposures does not address variability in exposure duration
and frequency. An additional uncertainty includes the use of exposure data generated before the
OSHA Methylene Chloride standard was updated in 1997.
5.2.2 Non-Cancer Risk Estimates
The risk estimates of non-cancer effects (expressed as margins of exposure or MOEs) refer to
adverse health effects associated with health endpoints other than cancer, including to the body's
organ systems, such as reproductive/developmental effects, cardiac and lung effects, and kidney
and liver effects. The MOE is the point of departure (POD) (an approximation of the no-
observed adverse effect level (NOAEL) or benchmark dose level (BMDL)) and the
corresponding human equivalent concentration (HEC) for a specific health endpoint divided by
the exposure concentration for the specific scenario of concern. Section 3.2.5 of this Risk
Evaluation presents the PODs for acute and chronic non-cancer effects for methylene chloride
and Section 4.3 of this Risk Evaluation presents the MOEs for acute and chronic non-cancer
effects.
The MOEs are compared to a benchmark MOE. The benchmark MOE accounts for the total
uncertainty in a POD, including, as appropriate: (1) the variation in sensitivity among the
members of the human population (i.e., intrahuman/intraspecies variability); (2) the uncertainty
in extrapolating animal data to humans (i.e., interspecies variability); (3) the uncertainty in
extrapolating from data obtained in a study with less-than-lifetime exposure to lifetime exposure
(i.e., extrapolating from subchronic to chronic exposure); and (4) the uncertainty in extrapolating
from a lowest observed adverse effect level (LOAEL) rather than from a NOAEL. A lower
benchmark MOE (e.g., 30) indicates greater certainty in the data (because fewer of the default
uncertainty factors (UFs) relevant to a given POD as described above were applied). A higher
benchmark MOE (e.g., 1000) would indicate more uncertainty for specific endpoints and
scenarios. However, these are often not the only uncertainties in a risk evaluation. The
benchmark MOE for acute non-cancer risks for methylene chloride is 30 (accounting for
intraspecies and LOAEL to NOAEL variability for an effect of small magnitude in a human
study). The benchmark MOE for chronic non-cancer risks for methylene chloride is 10
(accounting for interspecies and intraspecies variability in toxicodynamics); toxicokinetic
differences are accounted for in the PBPK modeling). Additional information regarding the non-
cancer hazard identification is in section 3.2.3.1 and the benchmark MOE is in Section 4.3 of this
Risk Evaluation.
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5.2.3 Cancer Risk Estimates
Cancer risk estimates represent the incremental increase in probability of an individual in an
exposed population developing cancer over a lifetime (excess lifetime cancer risk (ELCR))
following exposure to the chemical. Standard cancer benchmarks used by EPA and other
regulatory agencies are an increased cancer risk above benchmarks ranging from 1 in 1,000,000
to 1 in 10,000 (i.e., lxlO"6 to lxlO"4) depending on the subpopulation exposed. For example, in
this risk evaluation, EPA used lxlO"4 as the benchmark for the cancer risk to individuals in
industrial and commercial workplaces. The lxlO"4 value is not a bright line and EPA has
discretion to make an unreasonable risk determination for the chemical substance based on other
benchmarks as appropriate. Additional information regarding the cancer benchmark is in Section
4.3.1 of this Risk Evaluation.
5.2.4 Determining Unreasonable Risk of Injury to Health
Calculated risk estimates (MOEs or cancer risk estimates) can provide a risk profile of methylene
chloride by presenting a range of estimates for different health effects for different conditions of
use. A calculated MOE that is less than the benchmark MOE supports a determination of
unreasonable risk of injury to health, based on noncancer effects. Similarly, a calculated cancer
risk estimate that is greater than the cancer benchmark supports a determination of unreasonable
risk of injury to health from cancer. Whether EPA makes a determination of unreasonable risk
for the chemical substance depends upon other risk-related factors, such as the endpoint under
consideration, the reversibility of effect, exposure-related considerations (e.g., duration,
magnitude, or frequency of exposure, or population exposed), and the confidence in the
information used to inform the hazard and exposure values.
In the methylene chloride risk characterization, neurotoxicity effects (central nervous system
(CNS) depression) were identified as the most sensitive endpoint for non-cancer adverse effect
from acute inhalation and dermal exposures and liver effects were identified as the most sensitive
endpoint for non-cancer adverse effects from chronic inhalation and dermal exposures for all
conditions of use. However, additional risks associated with other adverse effects (e.g., other
nervous system effects, immune system effects; reproductive and developmental effects; and
irritation/burns) were identified for acute and chronic exposures. EPA expects that addressing the
unreasonable risk presented by methylene chloride for acute CNS and chronic liver effects would
also address the risk from other endpoints resulting from acute or chronic inhalation and dermal
exposures.
In accordance with EPA's Guidelines for Carcinogen Risk Assessment, methylene chloride is
considered "likely to be carcinogenic to humans" and EPA calculated cancer risk estimates with
a linear model. The cancer analysis is described in Section 3.2. EPA considered cancer risks
estimates from chronic dermal or inhalation exposures in the unreasonable risk determination.
When making a determination of unreasonable risk for the chemical substance, the Agency has a
higher degree of confidence where uncertainty is low. For example, EPA has high confidence in
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the hazard and exposure characterizations when the basis for characterizations is measured data
or representative monitoring data or a robust model and the hazards identified for risk estimation
are relevant for conditions of use. This Risk Evaluation discusses major assumptions and key
uncertainties; for example, where EPA has made assumptions in the scientific evaluation,
whether those assumptions are "conservative" (that is the degree to which these assumptions err
on the side of protection) is also a consideration. The high volatility of methylene chloride and
potentially severe effects from short term (1-hr) exposure are considerations when weighing the
role of uncertainties in decision making for methylene chloride. For the human health risk
estimation, key assumptions and uncertainties are related to the estimates for ONU inhalation
exposures, because monitoring data were not reasonably available for many of the conditions of
use evaluated. An additional source of uncertainty is the inhalation to dermal route-to-route
extrapolations, which is a source of uncertainty in the dermal risk assessment for dermal cancer
and non-cancer risk estimates. Similarly, for assessing cancer risks, although EPA chose to
model the combination of liver and lung tumor results from a cancer bioassay using mice, there
is uncertainty regarding the modeling of these tumor types for humans. Important assumptions
and key sources of uncertainty in the risk characterization are described in more detail in Section
4.4 of this Risk Evaluation.
When determining the unreasonable risk for a chemical substance, EPA considers the central
tendency and high-end exposure levels in occupational settings, and low, moderate and high
intensity of use for consumer uses. Risk estimates based on high-end exposure levels or high
intensity use scenarios (e.g., 95th percentile) are generally intended to cover individuals or sub-
populations with greater exposure (PESS) as well as to capture individuals with sentinel
exposure, and risk estimates at the central tendency exposure are generally estimates of average
or typical exposure (Section 4.4 of this Risk Evaluation).
As shown in Section 4 of this Risk Evaluation, when characterizing the risk to human health
from occupational exposures during risk evaluation under TSCA, EPA believes it is appropriate
to evaluate the levels of risk present in baseline scenarios where PPE is not assumed to be used
by workers. It should be noted that, in some cases, baseline conditions may reflect certain
mitigation measures, such as engineering controls, in instances where exposure estimates are
based on monitoring data at facilities that have engineering controls in place. This approach of
not assuming PPE use by workers considers the risk to potentially exposed or susceptible
subpopulations (workers and ONUs) who may not be covered by Occupational Safety and
Health Administration (OSHA) standards, such as self-employed individuals and public sector
workers who are not covered by a State Plan. In addition, EPA risk evaluations may characterize
the levels of risk present in scenarios considering applicable OSHA requirements (e.g., chemical-
specific PELs and/or chemical-specific health standards with PELs and additional ancillary
provisions), as well as scenarios considering industry or sector best practices for industrial
hygiene that are clearly articulated to the Agency. EPA's evaluation of risk under scenarios that,
for example, incorporate use of engineering or administrative controls, or personal protective
equipment, serves to inform its risk management efforts. By characterizing risks using scenarios
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that reflect different levels of mitigation, EPA risk evaluations can help inform potential risk
management actions by providing information that could be used to tailor risk mitigation
appropriately to address worker exposures where the Agency has found unreasonable risk. In
particular, EPA can use the information developed during its risk evaluation to determine
whether alignment of EPA's risk management requirements with existing OSHA requirements or
industry best practices will adequately address unreasonable risk as required by TSCA.
When undertaking unreasonable risk determinations as part of TSCA risk evaluations, EPA
cannot assume as a general matter that an applicable OSHA requirement or industry practice is
consistently and always properly applied. Mitigation scenarios included in the methylene
chloride risk evaluation (e.g., scenarios considering use of various personal protective equipment
(PPE)) likely represent what is happening already in some facilities. However, the Agency
cannot assume that all facilities will have adopted these practices for the purposes of making the
TSCA risk determination.
Therefore, EPA conducts baseline assessments of risk and makes its determination of
unreasonable risk from a baseline scenario that is not based on an assumption of compliance with
OSHA standards, including any applicable exposure limits or requirements for use of respiratory
protection or other PPE. Making unreasonable risk determinations based on the baseline scenario
should not be viewed as an indication that EPA believes there are no occupational safety
protections in place at any location, or that there is widespread noncompliance with applicable
OSHA standards. Rather, it reflects EPA's recognition that unreasonable risk may exist for
subpopulations of workers that may be highly exposed because they are not covered by OSHA
standards, such as self-employed individuals and public sector workers who are not covered by a
State Plan, or because their employer is out of compliance with OSHA standards, or because
many of OSHA's chemical-specific permissible exposure limits largely adopted in the 1970's are
described by OSHA as being "outdated and inadequate for ensuring protection of worker
health,"4 or because the OSHA PEL alone may be inadequate to protect worker health, or
because EPA finds unreasonable risk for purposes of TSCA notwithstanding existing OSHA
requirements.
The revised unreasonable risk determination for methylene chloride is based on the peer
reviewed risk characterization of the June 2020 Risk Evaluation, which was developed according
to TSCA section 26(h) requirements to make science-driven decisions, consistent with best
available science. Changing the risk determination to a whole chemical approach does not impact
the underlying data and analysis presented in the risk characterization of the risk evaluation.
Section 4.5.2 and Table 4-27 of this Risk Evaluation summarize the risk estimates with and
without PPE, and informed the revised unreasonable risk determination.
4 As noted on OSHA's Annotated Table of Permissible Exposure Limits: "OSHA recognizes that many of its
permissible exposure limits (PELs) are outdated and inadequate for ensuring protection of worker health. Most of
OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970, and
have not been updated since that time" (Ref. 5).
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5.3 Unreasonable Risk to the Environment
5.3.1 Environment
EPA's Risk Evaluation considered the effects of exposures to methylene chloride for aquatic,
sediment dwelling, and terrestrial organisms. The environmental hazard threshold is calculated
for aquatic, sediment dwelling, and terrestrial organisms.
EPA calculated a risk quotient (RQ) to compare environmental concentrations against an effect
level. The environmental concentration is determined based on the levels of the chemical
released to the environment (e.g., surface water, sediment, soil, biota) under the conditions of
use, based on the fate properties, release potential, and reasonably available environmental
monitoring data. The effect level is calculated using concentrations of concern that represent
hazard data for aquatic, sediment-dwelling, and terrestrial organisms. Section 4.2 of this Risk
Evaluation provides more detail regarding the environmental risk characterization for methylene
chloride.
5.3.2 Determining Unreasonable Risk of Injury to the Environment
Calculated risk quotients (RQs) can provide a risk profile by presenting a range of estimates for
different environmental hazard effects for different conditions of use. An RQ equal to 1 indicates
that the exposures are the same as the concentration that causes effects. An RQ less than 1, when
the exposure is less than the effect concentration, generally indicates that there is not risk of
injury to the environment that would support a determination of unreasonable risk for the
chemical substance. An RQ greater than 1, when the exposure is greater than the effect
concentration, generally indicates that there is risk of injury to the environment that would
support a determination of unreasonable risk for the chemical substance. Consistent with EPA's
human health evaluations, the RQ is not treated as a bright line and other risk-based factors may
be considered (e.g., confidence in the hazard and exposure characterization, duration, magnitude,
uncertainty) for purposes of making an unreasonable risk determination.
For all conditions of use, EPA has determined based on the RQ values (Table 4-4 and 4-5) in
water for acute and chronic exposures to methylene chloride for amphibians, fish, and aquatic
invertebrates that the conditions of use do not drive the unreasonable risk by presenting
unreasonable risk of injury to the environment. To characterize the exposure to methylene
chloride by aquatic organisms, modeled data were used to represent surface water concentrations
near facilities actively releasing methylene chloride to surface water, and monitored
concentrations were used to represent ambient water concentrations of methylene chloride. EPA
considered the biological relevance of the species to determine the concentrations of concern for
the location of surface water concentration data to produce RQs, as well as frequency and
duration of the exposure. Some site-specific RQs, calculated from modeled release data from
facilities conducting recycling, disposal, and wastewater treatment plant activities are greater
than or equal to one. Uncertainties related to these particular estimates are discussed in section
4.2.2. Uncertainties in the analysis include limitations in data, since monitoring data were not
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available near facilities where methylene chloride is released, and TRI does not capture release
data for facilities with fewer than ten employees. As an additional uncertainty, the model does
not consider chemical fate or hydrologic transport properties and may not consider dilution in
static water bodies. As described in section 4.4.6, additional analysis indicated that model
outputs, rather than monitoring estimates, may best represent concentrations found at the point of
discharge from the facilities.
Without toxicity data on sediment-dwelling invertebrates, EPA assumed the toxicity of
methylene chloride to sediment-dwelling invertebrates is similar to the toxicity to aquatic
invertebrates. Methylene chloride is most likely present in the pore waters and not absorbed to
the sediment organic matter because methylene chloride has low partitioning to organic matter.
The concentrations in sediment pore water are similar to or less than the concentrations in the
overlying water, and concentrations in the deeper part of sediment are lower than the
concentrations in the overlying water. Therefore, for sediment dwelling organisms the risk
estimates from acute and chronic exposures, based on the highest ambient surface water
concentration, do not support the inclusion of these risks as drivers of the unreasonable risk
determination for methylene chloride. There is uncertainty due to the lack of ecotoxicity studies
specifically for sediment-dwelling organisms and limited sediment monitoring data.
Based on its physical-chemical properties, methylene chloride does not partition to or
accumulate in soil and thus does not pose risk to terrestrial organisms. Therefore, these physical
chemical properties, do not support the inclusion of these exposures as drivers of the
unreasonable risk determination.
When making a determination of unreasonable risk, EPA has a higher degree of confidence
where uncertainty is low. For example, EPA has high confidence in the hazard and exposure
characterizations when the basis for the characterizations is measured or representative
monitoring data or a robust model and the hazards identified for risk estimation are relevant for
conditions of use. Additionally, EPA considers the central tendency and high-end scenarios when
determining the unreasonable risk. High-end risk estimates (e.g., 90th percentile) are generally
intended to cover organisms or populations with greater exposure (those inhabiting ecosystems
near industries) and central tendency risk estimates are generally estimates of average or typical
exposure. For methylene chloride, key assumptions and uncertainties in the environmental risk
estimation include the uncertainty around modeled releases that used E-FAST 2014 with 2016
TRI data as well as 2016 DMR data to estimate releases. Some sites that manufacture, process,
or use methylene chloride may not report to these datasets, are not included in this analysis and
therefore actual environmental exposures may be underestimated. In the measured surface water
data and watershed analysis, the WQP Tools contains data from USGS-NWIS and STORET
databases, and is one of the largest environmental monitoring databases in the U.S.; however,
comprehensive information needed for data interpretation is not always reasonably available. As
a result, there are uncertainties in the reported monitoring data that are difficult to quantify with
Page 12 of 26
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Methylene Chloride
October 2022
regard to impacts on exposure estimates. Assumptions and key sources of uncertainty in the risk
characterization are detailed in Section 4.4.1. of this Risk Evaluation.
Although various degrees of uncertainty and assumptions were identified in the risk evaluation,
EPA did not identify risk of injury to the environment that would drive the unreasonable risk
determination for methylene chloride.
5.4 Additional Information Regarding the Basis for the
Unreasonable Risk Determination
Table 5-1 and Table 5-2 summarize the basis for the revised determination of unreasonable risk
of injury to health presented by methylene chloride. In these tables, a checkmark indicates the
type of effect and the exposure route to the population evaluated for each condition of use that
drives the unreasonable risk determination. As explained in Section 5.2, for the revised
unreasonable risk determination, EPA considered the effects on human health and the
environment of exposure to methylene chloride at the central tendency and high-end (or low,
moderate, and high intensity use), the exposures from the condition of use, the risk estimates,
and the uncertainties in the analysis. See Section 4.1.2 and 4.1.3 of the Risk Evaluation for a
summary of risk estimates.
Page 13 of 26
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Methylene Chloride October 2022
Table 5-1. Supporting Basis for the Revised Unreasonable Risk Determination for Human Health (Occupational Conditions of
Use)5
Life Cycle
Stage
Category"
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tcndencv
High
End
Central
Tcndencv
High
End
Central
Tcndencv
Manufacturing
Domestic
manufacturing
Manufacturing
Worker
Inhalation 8-Hr TWA
Inhalation 15-Minute TWA
S
Dermal
s
S
S
S
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Inhalation 15-Minute TWA
n/a
n/a
n/a
Manufacturing
Import
Import
Worker
Inhalation 8-Hr TWA
S
S
S
Inhalation 1-Hr TWA
S
S
Dermal
S
s
S
s
ONU
Inhalation 8-Hr TWA
n/a
n/a
s
n/a
Inhalation 1-Hr TWA
n/a
s
n/a
n/a
Processing
Processing as a
reactant
Intermediate in industrial gas
manufacturing (e.g.,
manufacture of fluorinated
gases used as refrigerants)
Worker
Inhalation 8-Hr TWA
S
S
Inhalation 15-Minute TWA
Intermediate for pesticide,
fertilizer, and other agricultural
chemical manufacturing
Dermal
S
S
Petrochemical manufacturing
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Intermediate for other
chemicals
Inhalation 15-Minute TWA
5 The checkmarks indicate the type of effect and the exposure route to the population evaluated for each condition of use that support the revised unreasonable
risk determination for methylene chloride. This table is based on Table 4-2 of this Risk Evaluation.
Page 14 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Processing
Incorporation into
formulation,
mixture or
reaction products
Solvents (for cleaning or
degreasing), including
manufacturing of:All other
basic organic chemical; Soap,
cleaning compound and toilet
preparation
Worker
Inhalation 8-Hr TWA
Solvents (which become part of
product formulation or
mixture), including
manufacturing of: All other
chemical product and
preparation; paints and coatings
Propellants and blowing agents
for all other chemical product
and preparation manufacturing
Propellants and blowing agents
for plastics product
manufacturing
Paint additives and coating
additives not described by other
codes
Laboratory chemicals for all
other chemical product and
preparation manufacturing
Laboratory chemicals for other
industrial sectors
Processing aid, not otherwise
listed for petrochemical
manufacturing
Adhesive and sealant chemicals
in adhesive manufacturing
Oil and gas drilling, extraction,
and support activities
Inhalation 15-Minute TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Inhalation 15-Minute TWA
Page 15 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Processing
Repackaging
Solvents (which become part of
product formulation or mixture)
for all other chemical product
and preparation manufacturing.
All other chemical product and
preparation manufacturing.
Worker
Inhalation 8-Hr TWA
Inhalation 1-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Inhalation 1-Hr TWA
n/a
n/a
n/a
Processing
Recycling
Recycling
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Distribution in
commerce
Distribution
Distribution
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
Industrial /
commercial
use
Solvents (for
cleaning or
degreasing)
Batch vapor degreaser (e.g.,
open-top, closed-loop)
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
Industrial /
commercial
use
Solvents (for
cleaning or
degreasing)
In-line vapor degreaser (e.g.,
conveyorized, web cleaner)
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
Industrial /
commercial
use
Solvents (for
cleaning or
degreasing)
Cold cleaner
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Page 16 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Industrial /
commercial
use
Solvents (for
cleaning or
degreasing)
Aerosol spray degreaser/cleaner
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Adhesives and
Sealants
Single component glues and
adhesives and sealants and
caulks (spray and non-spray).
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Paints and coatings
and paint and
coating removers,
including furniture
refinisher
Paints and coatings
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Paints and coatings
and paint and
coating removers,
including furniture
refinisher
Paints and coating removers
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Adhesive /
caulk remover
Adhesive / caulk removers.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Metal products not
covered elsewhere
Degreasers - aerosol degreasers
and cleaners.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Metal products not
covered elsewhere
Degreasers -non-aerosol
degreasers and cleaners.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Page 17 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Industrial /
commercial
use
Fabric, textile and
leather products
not covered
elsewhere
Textile finishing and
impregnating/ surface treatment
products.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Automotive care
products
Function fluids for air
conditioners: refrigerant,
treatment, leak sealer.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Automotive care
products
Interior car care - spot remover.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Automotive care
products
Degreasers: gasket remover,
transmission cleaners,
carburetor cleaner, brake
quieter/cleaner.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Apparel and
footwear care
products
Post-market waxes and polishes
applied to footwear e.g., shoe
polish.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Laundry and
dishwashing
products
Spot remover for apparel and
textiles.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Lubricants and
greases
Liquid lubricants and greases.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Page 18 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Industrial /
commercial
use
Lubricants and
greases
Spray lubricants and greases.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Lubricants and
greases
Degreasers - aerosol degreasers
and cleaners.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Lubricants and
greases
Degreasers - non-aerosol
degreasers and cleaners.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Building/
construction
materials not
covered elsewhere
Cold pipe insulation.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Solvents (which
become part of
product
formulation or
mixture)
All other chemical product and
preparation manufacturing.
Worker
Inhalation 8-hr TWA
Inhalation 15-Minute TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Inhalation 15-Minute TWA
Industrial /
commercial
use
Processing aid not
otherwise listed
In multiple manufacturing
sectors.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Propellants and
blowing agents
Flexible polyurethane foam
manufacturing.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Page 19 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Industrial /
commercial
use
Other Uses
Laboratory chemicals - all other
chemical product and
preparation manufacturing.
Worker
Inhalation 8-Hr TWA
Inhalation 15-Minute TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Inhalation 15-Minute TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Electrical equipment, appliance,
and component manufacturing.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Plastic and rubber products.
Worker
Inhalation 8-Hr TWA
Inhalation 15-Minute TWA
Dermal
ONU
Inhalation 8-Hr TWA
Industrial /
commercial
use
Other Uses
Cellulose triacetate film
production.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Anti-adhesive agent - anti-
spatter welding aerosol.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Oil and gas drilling, extraction,
and support activities.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Page 20 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Categorya
Subcategory 6
Population
Exposure Route d
Human Health Effects
Acute
Non-cancer
Chronic Non-cancer
Cancer
High
End
Central
Tendency
High
End
Central
Tendency
High
End
Central
Tendcncv
Industrial /
commercial
use
Other Uses
Toys, playground, and sporting
equipment - including novelty
articles (toys, gifts, etc.)
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Lithographic printing cleaner.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Industrial /
commercial
use
Other Uses
Carbon remover, Wood floor
cleaner, and Brush cleaner.
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
Disposal
Disposal
Industrial pre-treatment
Industrial wastewater treatment
Publicly owned treatment works
(POTW)
Underground injection
Municipal landfill
Hazardous landfill
Other land disposal
Municipal waste incinerator
Off-site waste transfer
Worker
Inhalation 8-Hr TWA
Dermal
ONU
Inhalation 8-Hr TWA
n/a
n/a
n/a
3 These categories of conditions of use appear in the Life Cycle Diagram, reflect CDR codes, and broadly represent additional information regarding all conditions of use of
methylene chloride.
b These subcategories reflect more specific information regarding the conditions of use of methylene chloride.
- When the difference between ONUs' exposures and workers' exposures could not be quantified, EPA assumed that ONU inhalation exposures are lower than inhalation
exposures for workers directly handling the chemical substance, and considered the central tendency risk estimate when determining ONU risk.
J 15-min TWA are shown for conditions of use that had available exposure data and when risks from acute exposure indicated were different from 8-hr TWA. See Section
4.2.2.1 of this risk evaluation for details of 15-min TWAs for each occupational exposure scenario.
Page 21 of 26
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Methylene Chloride
October 2022
Table 5-2. Supporting Basis for the Revised Unreasonable Risk Determination for Human Health (Consumer
Conditions of Use)
Life Cycle
Stage
Category"
Subcategory ''
Population
Exposure Route
and Duration
Human Health
Acute Non-cancer
High
Intensity Use
Moderate
Intensity Use
Low
Intensity Use
Consumer use
Solvents (for
cleaning and
degreasing)
Aerosol spray
degreaser/cleaner
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Adhesives
and Sealants
Single component
glues, adhesives,
sealants, and caulk
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Paints and
coatings
Including
paint and
coating
removers
Brush cleaner for
paints and coatings
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Paints and
coatings
Including
paint and
coating
removers
Adhesive/caulk
removers
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Page 22 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Category"
Subcategory 6
Population
Exposure Route
and Duration
Human Health
Acute Non-cancer
High
Intensity Use
Moderate
Intensity Use
Low
Intensity Use
Consumer use
Metal
products not
covered
elsewhere
Degreasers - aerosol
and non-aerosol
degreasers (metal
degreasers)
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Automotive
care
products
Functional fluids for
air conditioners
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Automotive
care
products
Degreasers: gasket
remover, transmission
cleaners, carburetor
cleaner, brake
quieter/cleaner
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Consumer use
Consumer use
Lubricants
and greases
Lubricants
and greases
Degreasers - Aerosol
and non-aerosol
degreasers and cleaners
Consumer user
Inhalation 1-hour
Inhalation 8-hour
Dermal
Bystander
Inhalation 1-hour
Inhalation 8-hour
Page 23 of 26
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Methylene Chloride
October 2022
Life Cycle
Stage
Category"
Subcategory 6
Population
Exposure Route
and Duration
Human Health
Acute Non-cancer
High
Intensity Use
Moderate
Intensity Use
Low
Intensity Use
Consumer use
Building /
construction
materials not
covered
elsewhere
Cold pipe insulation
Consumer user
Inhalation 1-hour
S
S
S
Inhalation 8-hour
S
S
Dermal
s
s
Bystander
Inhalation 1-hour
s
s
Inhalation 8-hour
s
s
Consumer use
Arts,
crafts, and
hobby
materials
Crafting glue and
cement/concrete
Consumer user
Inhalation 1-hour
s
s
Inhalation 8-hour
s
s
Dermal
s
s
Bystander
Inhalation 1-hour
s
Inhalation 8-hour
s
Consumer use
Other Uses
Anti-adhesive agent
Consumer user
Inhalation 1-hour
s
s
s
Inhalation 8-hour
s
s
s
Dermal
s
s
Bystander
Inhalation 1-hour
s
s
Inhalation 8-hour
s
s
" These categories of conditions of use appear in the Life Cycle Diagram, reflect CDR codes, and broadly represent additional information regarding all
conditions of use of methylene chloride.
b These subcategories reflect more specific information regarding the conditions of use of methylene chloride.
Page 24 of 26
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Methylene Chloride October 2022
5.5 Order Withdrawing TSCA Section 6(i)(l) Order
The June 2020 risk evaluation for methylene chloride included individual risk determinations for
each condition of use evaluated. The determinations that particular conditions of use did not
present unreasonable risk were issued by order under TSCA section 6(i)(l). Section 5.4.1 of the
June 2020 Risk Evaluation stated: "This subsection of the final Risk Evaluation ... constitutes
the order required under TSCA section 6(i)(l), and the 'no unreasonable risk' determinations in
this subsection are considered to be final agency action effective on the date of issuance of this
order."
In this revised risk determination, EPA has determined that methylene chloride as a whole
chemical substance presents an unreasonable risk of injury to health under the conditions of use.
This revised risk determination supersedes the no unreasonable risk determinations in the June
2020 Risk Evaluation that were premised on a condition of use-specific approach to determining
unreasonable risk. This subsection of the revised risk determination also constitutes an order
withdrawing the TSCA section 6(i)(l) order in the June 2020 Risk Evaluation. EPA has inherent
authority to reconsider previous decisions and to revise, replace, or repeal a decision to the to the
extent permitted by law and supported by reasoned explanation. FCC v. Fox Television Stations,
Inc., 556 U.S. 502, 515 (2009); see also Motor Vehicle Mfrs. Ass'n v. State Farm Mutual Auto.
Ins. Co., 463 U.S. 29, 42 (1983). Further explanation and justification for this action can be
found in the Federal Register Notice announcing the availability of the draft revised risk
determination for methylene chloride, 87 Fed. Reg. 39824 (July 5, 2022) (Ref. 8), and in the
Federal Register Notice accompanying this revised risk determination.
5.6 References
1. EPA. Risk Evaluation for Methylene Chloride (MC). June 2020.
https://www.regulations.gov/document/EPA-HQ-OPPT-2019-0437-01Q7.
2. Executive Order 13985. Advancing Racial Equity and Support for Underserved Communities
Through the Federal Government. Federal Register (86 FR 7009, January 25, 2021).
3. Executive Order 13990. Protecting Public Health and the Environment and Restoring Science
to Tackle the Climate Crisis. Federal Register (86 FR 7037, of January 25, 2021).
4. Executive Order 14008. Tackling the Climate Crisis at Home and Abroad. Federal Register
(86 FR 7619, February 1, 2021).
5. Presidential Memorandum. Memorandum on Restoring Trust in Government Through
Scientific Integrity and Evidence-Based Policymaking. Federal Register (86 FR 8845, February
10, 2021).
6. EPA Press Release. EPA Announces Path Forward for TSCA Chemical Risk Evaluations.
June 30, 2021. https://www.epa.gov/newsreleases/epa-announces-path-forward-tsca-chemical-
risk-evaluations
Page 25 of 26
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Methylene Chloride
October 2022
7. Occupational Safety and Health Administration. Permissible Exposure Limits - Annotated
Tables. Accessed June 13, 2022. https://www.osha.gov/annotated-pels
8. Notice. Methylene Chloride; Draft Revision to Toxic Substances Control Act (TSCA) Risk
Determination; Notice of Availability and Request for Comment. Federal Register (87 Fed. Reg.
39824 (July 5, 2022).
9. EPA. Methylene Chloride; Revision to Toxic Substances Control Act (TSCA) Risk
Determination: Response to Public Comments. October 2022. Available at: docket EPA-HQ-
OPPT-2016-0742.
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