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EPA Grants Manufacturer Request for Risk Evaluation of D4

For Release: October 7, 2020

After reviewing the request and public comments, EPA is granting a manufacturer request for a risk evaluation of octamethylcyclotetra-siloxane (D4), a chemical used to make other silicone chemicals and as an ingredient in some personal care products. If the request is not withdrawn within 30 days, D4 will enter the Toxic Substances Control Act (TSCA) risk evaluation process.

Under TSCA, chemical manufacturers can request that EPA conduct a risk evaluation on a specific chemical. By giving manufacturers the opportunity to prioritize, identify, and request the evaluation of chemicals and conditions of use of interest to them, EPA is encouraging sensible and timely assessment of chemicals in the marketplace. Manufacturer-requested risk evaluations are conducted in the same manner as other TSCA risk evaluations.

Learn more about the D4 manufacturer-requested risk evaluation.


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. 

Learn more about manufacturer-requested risk evaluations.