Background on Risk Evaluation Under the Toxic Substances Control Act (TSCA): Perchloroethylene
INSIGHTi
Background on Risk Evaluation Under the
Toxic Substances Control Act (TSCA):
Perchloroethylene
September 12, 2022
In 2016, the Frank R. Lautenberg Chemical Safety for the 21st Century Act (LCSA; P.L. 114-182)
amended Title I of the Toxic Substances Control Act (TSCA; 15 U.S.C. §2601 et seq.) to direct the U.S.
Environmental Protection Agency (EPA) to systematically prioritize chemicals for risk evaluation. (For
more information, see CRS Report R45149, Title I of the Toxic Substances Control Act (TSCA): A
Summary of the Statute.) The purpose of the risk evaluations is to determine whether particular chemicals
warrant regulation in terms of the risks associated with their manufacture, processing, distribution, use, or
disposal. If EPA identifies “unreasonable” risk to human health or the environment associated with one or
more of the elements of a chemical’s lifecycle, TSCA Section 6 directs EPA to promulgate a rule to
mitigate those risks. TSCA Section 9 limits EPA’s authority to regulate a chemical under TSCA if another
law may be used to regulate a chemical for the unreasonable risk identified by the agency.
As amended, TSCA Section 6 directed EPA to select 10 chemicals for risk evaluation from a list of 90
chemicals that the agency identified in 2014 as warranting risk assessment. EPA based this list on a
screening of 345 chemicals for potential hazard and exposure, and persistence and bioaccumulation
characteristics. With more than 86,000 chemicals on the TSCA Inventory, EPA’s screening approach was
intended to focus the agency’s resources and attention on a select group of chemicals for which sufficient
scientific and technical information is available to suggest greater concern to human health or the
environment. Pursuant to TSCA Section 6, EPA selected the initial 10 chemicals for risk evaluation,
including perchloroethylene (PCE), in 2016 (81 Federal Register 91927-91929, December 19, 2016).
Each chemical substance that EPA evaluates has unique properties, uses, and risks, which may warrant
different risk management approaches. The process of conducting risk evaluations and assessing risk
management options involves judgments about the reliability of available scientific and technical
information. Aspects of this process and what information EPA identifies as the basis for justifying certain
regulatory action can generate disagreement between the agency and stakeholders (e.g., industry,
environmental and public health organizations). As EPA continues to implement TSCA, the agency’s risk
evaluations and related actions are likely to receive scrutiny among stakeholders. Congress may consider
assessing EPA’s implementation of TSCA, as amended by the LCSA, and the resulting outcomes from the
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agency’s actions and decisions. The next section discusses EPA’s risk evaluation for PCE and potential
next steps toward addressing the unreasonable risks that the agency identified.
Perchloroethylene (PCE)
In 2016, EPA selected PCE (CAS Number 127-81-4) as one of the initial 10 chemicals for a risk
evaluation. According to EPA, over 300 million pounds of PCE are manufactured in, or imported to, the
United States annually. The predominant use of PCE is for the manufacture of industrial gases and
fluorinated chemicals. PCE is also used as a solvent for dry cleaning, vapor degreasing, and other
miscellaneous uses. The TSCA risk evaluation builds upon existing scientific understanding of the risks
associated with PCE to determine whether there may be unreasonable risks associated with current uses
of PCE that may warrant additional control.
In December 2020, EPA finalized its risk evaluation for PCE, identifying unreasonable risks to the health
of workers, occupational non-users, consumers, and bystanders from 59 of 61 conditions of use evaluated.
EPA did not identify unreasonable risks to the environment for the conditions of use evaluated by the
agency. EPA based its risk determinations on a comparison of various sources of scientific information.
EPA considered the predicted exposure to PCE from various exposure scenarios (e.g., workers involved in
handling the chemical with or without the use of a respirator), the estimated level of exposure expected
not to result in the development of adverse noncarcinogenic health effects while taking into account a
margin of exposure, and the estimated level of exposure expected not to increase the risk of developing
particular cancers above certain guideline ranges (i.e., 1-in-10,000 to 1-in-a-million above background
risk). EPA’s risk determinations regarding potential environmental effects are based the predicted
exposure to PCE for various species compared to the estimated level of exposure expected not to result in
the development of adverse effects in species at the population level.
In June 2021, EPA announced its intention to approach the TSCA unreasonable risk determinations by
making one determination for a chemical substance rather than multiple determinations for each condition
of use. In June 2022, EPA released a draft revised risk determination for PCE, which indicates that the
chemical presents unreasonable risks to human health. This revised risk determination would supersede
the December 2020 risk determinations in the risk evaluation.
Given that EPA identified unreasonable risks associated with PCE, the agency is developing a rule under
TSCA Section 6 to address such risks. Section 6(a) identifies seven risk management options that EPA
may use alone or in combination to address the risks of PCE, including prohibiting the manufacture of the
chemical and requiring manufacturers of the chemical to communicate the chemical’s risks to allow
downstream processors, users, and distributors the opportunity to take applicable protective measures. In
developing the rule, EPA is required pursuant to Section 6 to identify various risk management options
that would adequately address the identified unreasonable risk and determine the associated costs for each
proposed risk management option.
In its risk evaluation, EPA acknowledged multiple existing regulations that apply to PCE. These
regulations (e.g., occupational standards, stationary source air emissions standards, and drinking water
standards) were promulgated under various statutes that EPA and other agencies administer. A TSCA risk
management rule could supplement these existing regulations.
Since PCE is manufactured at relatively high volumes, those who manufacture and use PCE are likely to
scrutinize the forthcoming risk management rule and underlying risk evaluation. Congress may conduct
oversight or consider legislation with regard to EPA’s efforts to manage risks associated with PCE and
whether such efforts are aligned with the intent of the TSCA amendments.
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Author Information
Jerry H. Yen
Analyst in Environmental Policy
Disclaimer
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