EPA is asking for public input on the draft scope document for a manufacturer-requested risk evaluation of octamethylcyclotetra-siloxane (D4), a chemical used to make other silicone chemicals and as an ingredient in some personal care products. The draft scope document for the Toxic Substances Control Act (TSCA) risk evaluation for D4 includes the conditions of use, hazards, exposures, and the potentially exposed or susceptible subpopulations that the EPA will consider in the risk evaluation. The document includes the following: - A description of the reasonably available information and the best available science approaches that the agency will use;
- A conceptual model that outlines the potential hazards and exposures throughout the life cycle of the chemical;
- An analysis plan to identify the approaches and methods EPA will use to assess health and environmental risks; and
- A plan for peer review.
The draft scope document reflects EPA's policy changes on risk evaluations announced in June. This includes the addition of exposure pathways that may be regulated outside of TSCA, like air and water, and potential exposure to fenceline communities (i.e., communities near industrial facilities). Assumptions that personal protective equipment (PPE) in occupational settings will always be properly utilized will not be the basis for the risk determination. Use of PPE, and other ways industry protects its workers, will be assessed during the risk evaluation and considered during risk management. This is consistent with the agency's plan to consider PPE, and other ways industry protects its workers, as a potential way to address unreasonable risks during the risk management process. Going forward, evaluations of existing chemicals, including D4, will ensure unreasonable risks from chemicals are assessed in a way that is supported by science and the law. Under TSCA, chemical manufacturers can request that EPA conduct a risk evaluation on a specific chemical. Manufacturer-requested risk evaluations are generally conducted in the same manner as other risk evaluations conducted under TSCA. EPA is accepting comments on the draft scope document for 45 days. Comments may be submitted to the docket EPA-HQ-OPPT-2018-0443. EPA will use feedback received from the public comment process to inform the final scope documents. Background On March 19, 2020, EPA received a manufacturer request to conduct a risk evaluation of D4 from Dow Silicones Corporation, Elkem Silicones USA Corporation, Evonik Corporation, Momentive Performance Materials, Shin-Etsu Silicones of America, Inc., and Wacker Chemical Corporation through the American Chemistry Council's Silicones Environmental, Health, and Safety Center. On April 8, 2020, EPA found this request to be facially complete. A 45-day public comment period was opened for this request on June 17, 2020, which allowed the public to submit comments relevant to the requested risk evaluation. On October 6, 2020, EPA granted the manufacturer request for a risk evaluation of D4. | 
