U.S. Environmental Protection Agency seeking comments on draft scope of risk evaluation for octamethylcyclotetra-siloxane

Washington, D.C. – In accordance with implementing regulations for the Toxic Substances Control Act (TSCA), the Environmental Protection Agency (EPA) is announcing the availability of and soliciting public comment on the draft scope of the risk evaluation to be conducted for octamethylcyclotetra-siloxane (D4). D4 (cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-; Chemical Abstracts Service Registry Number (CASRN) 556-67-2), is a chemical substance for which the EPA received a manufacturer request for risk evaluation. The draft scope for this chemical substance includes the conditions of use, hazards, exposures and the potentially exposed or susceptible subpopulations that EPA plans to consider in conducting the risk evaluation for this chemical substance. EPA is also opening a 45 calendar day comment period on the draft scope to allow for the public to provide additional data or information that could be useful to the agency in finalizing the scope of the risk evaluation.

Comments must be received on or before October 25.

To submit comments, identified by docket identification (ID) number EPA-HQ-OPPT-2018-0443, online using the Federal eRulemaking Portal at Follow the online instructions for submitting comments. Do not submit electronically any information considered to be confidential business information (CBI) or other information whose disclosure is restricted by statute. Additional instructions on commenting or visiting the docket, along with more information about dockets generally, is available at

For further information on EPA/DC services, docket contact information and the current status of the EPA/DC and reading room, visit

For technical information contact: Bethany Masten, Existing Chemical Risk Management Division, Office of Pollution Prevention and Toxics, Environmental Protection Agency (Mailcode 7404T), 1200 Pennsylvania Ave. NW, Washington, D.C. 20460-0001; telephone number: (202) 564-8803; email address:

EPA encourages commenters to provide information they believe might be missing or may further inform the risk evaluation. EPA will publish a notice in the Federal Register announcing the availability of the final scope of the risk evaluation within three months of publishing the draft scope.