EPA Requests Comment on Draft Documents for 1,1- and 1,2-Dichloroethane
On July 1, EPA released its draft risk evaluation for 1,1-dichloroethane and its draft human health hazard assessment for 1,2-dichloroethane, also known as ethylene dichloride. The agency is evaluating 1,2-dichloroethane under the Toxic Substances Control Act and has preliminarily determined that 1,1-dichloroethane may pose unreasonable risk to human health and the environment, according to a press release. The two chemicals are very similar in terms of physical structure and are thought to cause similar health effects, EPA states. Because 1,2-dichloroethane is the “better studied” of the two chemicals, EPA is requesting feedback on the draft hazard assessment for 1,2-dichloroethane to inform the agency’s understanding of the toxicity of 1,1-dichloroethane for the draft risk evaluation. Data collected via public comments may also inform EPA’s upcoming full draft risk evaluation for 1,2-dichloroethane.
EPA explains that 1,1-dichloroethane is used mainly as an industrial and commercial solvent, to make other chlorinated solvents and many other substances, and in small amounts for lab research, while 1,2-dichloroethane is primarily used to produce vinyl chloride. EPA’s press release and an information sheet for 1,2-dichloroethane published by the Agency for Toxic Substances and Disease Registry (ATSDR) describe both chemicals as colorless, oily liquids that may cause cancer of the kidneys and other organs. The chemicals may have harmful renal, nasal, immune system, and reproductive effects. The ATSDR page also states that exposure to large amounts of 1,2-dichloroethane may cause nausea, blurred vision, difficulty breathing, liver or kidney problems, and death. The new ASTDR toxicological profile 1,2 dichloroethane provides further information on the chemical’s properties and effects.
Given the inadequate data available on 1,1-dichloroethane, EPA used 1,2-dichloroethane as “the best available candidate to provide analogous human health data,” the agency’s press release explains. “Using analogues is a well-established risk assessment practice for chemicals that share structural similarities.”
Written comments will be accepted until noon on Aug. 23. Additional information on EPA’s actions concerning 1,1- and 1,2-dichloroethane, including how to submit comments, is available in the Federal Register notice. Interested parties may view supporting documents and submit comments through Regulations.gov. EPA will host a preparatory virtual public meeting on Aug. 27, at which attendees may discuss the scope and clarity of the draft with the agency’s Science Advisory Committee on Chemicals. Oral comments may be delivered at a public meeting to discuss the draft documents to be held Sept. 17–20.
EPA’s risk evaluations for 1,1-dichloroethane and 1,2-dichlorethane may be read on the agency’s website. More information may be found in EPA’s press release.