EPA Releases Draft Risk Evaluation of trans-1,2-Dichloroethylene

EPA’s draft risk evaluation for trans-1,2-dichloroethylene is available for public comment, the agency announced on Aug. 28. The substance is used in industry for cleaning, degreasing, and as a processing aid. Consumers may also be exposed to trans-1,2-dichloroethylene from the use of cleaners, degreasers, and foam insulation. 

The potential health effects of exposure to trans-1,2-dichloroethylene include sensory irritation and acute neurotoxicity. Exposure can also trigger an immune response. The draft risk evaluation explains that workers and occupational non-users face “unreasonable risk of injury to human health” from inhalation exposure to trans-1,2-dichloroethylene in 19 conditions of use, including manufacturing, processing, and several scenarios related to industrial or commercial use of the substance. EPA preliminarily determined that it does not expect exposure to trans-1,2-dichloroethylene to cause cancer.

EPA calculated an existing chemical occupational exposure value for inhalation exposures to trans-1,2-dichloroethylene of 0.63 ppm, or 2.5 mg/m3, as an eight-hour, time-weighted average (TWA). The agency may use this value when determining risk management efforts for the substance. The OSHA permissible exposure limit, NIOSH recommended exposure limit, and ACGIH Threshold Limit Value for isomers of 1,2-dichloroethylene is 200 ppm (790 mg/m3), also as eight-hour TWAs.

EPA also derived an acute exposure value for trans-1,2-dichloroethylene of 66.7 ppm, or 264 mg/m3, which, the agency states, can be applied as a 15-minute short-term limit. OSHA, NIOSH, and ACGIH have not developed short-term limits for isomers of 1,2-dichloroethylene.

Comments on the draft risk evaluation are due Oct. 26. The Federal Register notice about the availability of the draft risk evaluation indicates that EPA “is particularly interested in” comments on specific aspects of the use of trans-1,2-dichloroethylene such as the use of controls, frequency of tasks, and relevant studies or data sources that the agency has not yet identified. 

For more information, refer to the draft risk evaluation, the EPA website, and the docket on Regulations.gov.