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Draft Risk Evaluation for Trichloroethylene

In the draft trichloroethylene (TCE) risk evaluation, EPA reviewed 54 potential conditions of use. Below are the draft risk evaluation and supporting documents for TCE.

The draft risk evaluation is available for comment in the Federal Register until April 27, 2020 in docket EPA-HQ-OPPT-2019-0500EPA also will hold a peer review meeting of EPA’s Science Advisory Committee on Chemicals (SACC) on the draft risk evaluation for this chemical’s conditions of use on March 24-27, 2020.

To prepare a draft risk evaluation, EPA reviews extensive scientific literature, conducts modeling and other risk assessment activities, and collects exposure, fate, and transport information from many sources. EPA looks at how the chemical is used today, what we know about the chemical’s fate, transport, and toxicity, and whether  the chemical’s relevant conditions of use could pose an unreasonable risk of injury to human health or the environment. Learn more about EPA’s risk evaluation process.

On this page:

Draft Risk Evaluation Findings

In the February 2020 draft risk evaluation, EPA reviewed a suite of potential TCE exposures and made the following initial determinations on risk. These preliminary determinations may change as EPA's evaluation becomes more refined through the public comment and peer review processes.

EPA did not find risk to the environment. For all the conditions of use included in the draft risk evaluation, EPA has preliminarily found no unreasonable risks to the environment under any of the conditions of use.

EPA’s draft risk evaluation preliminarily found unreasonable risk associated with dermal and inhalation exposure for workers, occupational non-users, consumers, and bystanders. EPA found that workers, occupational non-users, consumers, and bystanders could be adversely affected by TCE under all but one condition of use. EPA did not find consumer use of pepper spray to present an unreasonable risk. These initial determinations are based on a draft risk evaluation of the reasonably available information and are not EPA’s final determinations on whether this chemical presents unreasonable risks under the conditions of use. The agency will use feedback received from the public comment and peer review processes to inform the final risk determinations. 

This draft risk evaluation and the initial risk determinations are not a final action. This draft represents the agency’s preliminary conclusions, findings, and determinations on TCE and will be peer reviewed by independent scientific experts. The draft risk evaluation includes input from other EPA offices as well as other federal agencies.

Using Products Safely and Alternatives

For any chemical product, EPA strongly recommends that users carefully follow all instructions on the product’s label and on the safety data sheets. Workers using TCE products should continue to follow the label/safety data sheets and applicable workplace regulations and should properly use appropriate personal protective equipment, as needed. Additionally, safety data sheets developed by the manufacturer remind users to only use the product in well-ventilated areas.

Consumers wishing to avoid exposure should ask retailers if products contain TCE and consider not using products that do contain TCE. Consumers also can choose to not use products where they do not know the active ingredients.

There are many solvents on the market, some of which might be suitable replacements for TCE depending on the condition of use. For vapor degreasing, alternatives to TCE with similar performance characteristics are available. Alternatives can include using different solvents, switching to aqueous cleaners, adopting other mechanical cleaning techniques, or equipment substitution. Alternative formulations of aerosol degreasers that do not contain TCE are available. There are also alternatives available to use as a spot cleaner in dry cleaning. Recent advances in both technology and garment care have resulted in alternatives to TCE and other dry cleaning solvents. 

Public Participation, Peer Review, and Next Steps

The draft risk evaluation is available for comment in the Federal Register until April 27, 2020 in docket EPA-HQ-OPPT-2019-0500.  This public comment period is an opportunity for the public to submit any additional information to assist EPA in completing the final risk evaluation for TCE. EPA will consider all comments submitted on the draft risk evaluation when developing a final risk evaluation.

EPA is committed to being open and transparent as the agency follows the process required by the law for evaluating unreasonable risks from chemicals. EPA will continue to keep the public updated as the agency moves through the risk evaluation process. Following the comprehensive risk evaluation process required by TSCA ensures that EPA has confidence in our final conclusions about whether a chemical substance poses any unreasonable risks of injury to health or the environment under the specific conditions of use. This then allows the public to have confidence in the safety of chemicals on the market.

The next step in the risk evaluation process is public participation. EPA is asking the public to provide input on the draft risk evaluation to ensure that the Agency is using the best available science and making decisions based on the weight of scientific evidence.

The draft risk evaluation will be peer reviewed by a panel of independent, scientific experts on March 24-27, 2020. EPA goes beyond what TSCA requires by peer reviewing the risk evaluations it releases in order to increase public transparency in the risk evaluation process and receive expert feedback on the science that underlies the risk determinations. Learn more about the peer review.

EPA’s preliminary risk determinations may change in response to comments from the public and from scientific experts conducting a peer review on the draft risk evaluation. If EPA’s final risk evaluation finds there are unreasonable risks associated with this chemical under the specific conditions of use, the agency will propose actions to address any unreasonable risks within the timeframe required by TSCA. This could include proposed regulations to prohibit or limit the manufacture, processing, distribution in the marketplace, use, or disposal of this chemicals, as applicable.

Draft Risk Evaluation and Supporting Files

Supplemental Information File: TCE Risk Calculator for Occupational Exposures (.xlsx)(252 K)

Supplemental Information File: TCE Exposure Modeling Results and Risk Estimates for Consumer Inhalation Exposures (.xlsx)(195 K)

Supplemental Information File: TCE Personal Communication to OPPT - Raw Data Values from Selgrade and Gilmour, 2010 (.xlsx)(120 K)

Supplemental Information File: TCE Consumer Exposure Model Input Parameters (.xlsx)(50 K)

Supplemental Information File: TCE Exposure Modeling Results and Risk Estimates for Consumer Dermal Exposures (.xlsx)(63 K)

Supplemental Information File: TCE Data Table for Congenital Heart Defects Weight of Evidence Analysis (.xlsx)(56 K)

Supplemental Information File: TCE PBPK Model (.zip)(1042 MB)

Note: The PBPK model and all associated files can be extracted from the .zip file posted above. Model equations are defined in .model files with precompiled .exe binaries provided for running the model on the windows operating system. The PBPK model unpacked folders (“ATSDR-comparison”, “Human.seqpriors.v1”, “Mouse”, and “Rat.seqpriors”) contain several file types (.in, .out, .model) necessary for running the PBPK model in MCSim. The .in files are the input files read by the compiled MCSim model while .out files are the corresponding outputs. Input (.in) files with “MCMC” in the file header correspond to inputs for the hierarchical parameterization of the species-specific model using Markov-Chain Monte Carlo. Input (.in) files with “SetPoints” as the file header run the PBPK model in MCSim by sampling from the joint posterior distributions generated using the MCMC simulation. Each of these .in files contain the exposure parameters for a given PBPK model simulation. Output (.out) results generated from a “SetPoints” simulation are used to determine the credible intervals for the desired dose metrics. Any new PBPK simulation would utilize a “SetPoints” simulation to sample the joint posterior distributions from the corresponding .out file with desired exposure parameters defined in the “Experiment” section of the .in file. All file types can be viewed in a text editor while .out files are tab delimited and can be viewed in Excel.

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