EPA Releases Draft Risk Evaluation for Solvent 1,1,2-Trichloroethane

EPA’s draft risk evaluation for 1,1,2-trichloroethane finds that inhalation and dermal exposures present “unreasonable risk to workers” from 10 conditions of use, including manufacturing, processing, repackaging, industrial uses, and disposal. According to EPA, 1,1,2-trichloroethane is primarily used in industry as a solvent and in plastic and petrochemical manufacturing. The agency’s draft chemistry, fate, release, and exposure assessment (PDF) explains that EPA considered exposures for workers who directly handle 1,1,2-trichloroethane and for “occupational non-users,” or ONUs, the agency’s term for those who may be exposed while working near where the substance is being used. EPA states that vapors, particulates, or mists that enter ONUs’ breathing zones are of potential concern regarding exposures. The agency previously classified 1,1,2-trichloroethane as a possible human carcinogen.

The draft risk evaluation includes a draft eight-hour, time-weighted average occupational exposure value for inhalation exposures to 1,1,2-trichloroethane of 0.001 ppm, or 0.005 mg/m3. The draft document explains that EPA calculated this value “for consideration in workplace settings” and may use it “to support risk management efforts.” For comparison, OSHA’s permissible exposure limit for 1,1,2-trichloroethane is currently set at 10 ppm, or 45 mg/m³, as an eight-hour TWA.

“[The Toxic Substances Control Act] requires risk evaluations to be conducted without consideration of cost and other non-risk factors, and thus this occupational exposure value represents a risk-only number,” the draft risk evaluation states. “EPA may consider cost and other non-risk factors, such as analytical and technological feasibility, the availability of alternatives, and the potential for critical or essential uses during risk management.”

EPA is seeking input on the draft risk evaluation for 1,1,2-trichloroethane until Sept. 28. During the comment period, the agency hopes to receive specific input on topics including how the substance is produced as a byproduct at pulp and paper manufacturing facilities as well as how it is used in adhesives, sealants, and in cleaning and degreasing applications.

The draft risk evaluation and supporting documents can be found on EPA’s risk evaluation webpage for 1,1,2-trichloroethane. Further details and instructions for submitting comments are available in the Federal Register.