United States Government Publishing Office publisher pbl distributor dst United States National Archives and Records Administration Office of the Federal Register author aut Government Organization text government publication eng FR Regulatory Information 2025_register executive 2025-11-13 article Notices D09002ee1d9e604d6 D09002ee1d9e604f5 United States Environmental Protection Agency originator org United States Government Agency or Subagency In the Federal Register of September 17, 2025, Environmental Protection Agency (EPA) announced the availability of and sought public comment on a draft risk evaluation under the Toxic Substances Control Act (TSCA) for Octamethylcyclotetrasiloxane (Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-) (D4) (CASRN 556-67-2). The purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use (COUs), including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, and without consideration of costs or non-risk factors. EPA used the best available science to prepare this draft risk evaluation and to preliminarily determine, based on the weight of scientific evidence, that D4 poses unreasonable risk to health and the environment driven primarily by COUs analyzed in the draft risk evaluation. This document extends the comment period, which was scheduled to end on November 17, 2025, for 15 days. 90 FR 50944 https://www.govinfo.gov/app/details/FR-2025-11-13/2025-19878 2025-19878 fr13no25-13 6560-50-P EPA-HQ-OPPT-2018-0443 FRL-12964-02-OCSPP https://www.govinfo.gov/app/details/FR-2025-11-13/2025-19878 https://www.govinfo.gov/content/pkg/FR-2025-11-13/html/2025-19878.htm https://www.govinfo.gov/content/pkg/FR-2025-11-13/pdf/2025-19878.pdf 1 p. 50944 50944 90 FR 50944 Octamethylcyclotetrasiloxane (Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-)(D4); Draft Risk Evaluation Under the Toxic Substances Control Act (TSCA); Extension of the Comment Period; Federal Register Vol. 90, Issue NOTICE 2025-19878 ENVIRONMENTAL PROTECTION AGENCY 2025-12-02 EPA-HQ-OPPT-2018-0443 FRL-12964-02-OCSPP 6560-50-P 2025-19878 Notice; extension of comment period.

In the Federal Register of September 17, 2025, Environmental Protection Agency (EPA) announced the availability of and sought public comment on a draft risk evaluation under the Toxic Substances Control Act (TSCA) for Octamethylcyclotetrasiloxane (Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-) (D4) (CASRN 556-67-2). The purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use (COUs), including unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the risk evaluation by EPA, and without consideration of costs or non-risk factors. EPA used the best available science to prepare this draft risk evaluation and to preliminarily determine, based on the weight of scientific evidence, that D4 poses unreasonable risk to health and the environment driven primarily by COUs analyzed in the draft risk evaluation. This document extends the comment period, which was scheduled to end on November 17, 2025, for 15 days.

The comment period for the document published on September 17, 2025, at 90 FR 44821 (FRL-12964-01-OCSPP) is extended. Comments must be received on or before December 2, 2025; 15 days after November 17, 2025. For technical information: Scott Drewes, Existing Chemical Risk Management Division (7404M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, Draft Risk Evaluation under the Toxic Substances Control Act Octamethylcyclotetrasiloxane (Cyclotetrasiloxane, 2,2,4,4,6,6,8,8octamethyl) (D4), drewes.scott@epa.gov TSCA-Hotline@epa.gov https://www.epa.gov/dockets https://www.regulations.gov Vol. 90, no. 217 Office of the Federal Register, National Archives and Records Administration 2025-11-13 continuing daily deposited born digital 132 p. Table of Contents: AE 2.7: GS 4.107: AE 2.106: KF70.A2 https://www.govinfo.gov/app/details/FR-2025-11-13 P0b002ee1d9dbb6e0 0097-6326 0042-1219 0364-1406 769-004-00000-9 000582072 f:fr13no25 https://www.govinfo.gov/app/details/FR-2025-11-13 https://www.govinfo.gov/content/pkg/FR-2025-11-13/pdf/FR-2025-11-13.pdf https://www.govinfo.gov/content/pkg/FR-2025-11-13/xml/FR-2025-11-13.xml fdlp 50891 51016 DGPO 2025-11-13 2025-11-13 FR-2025-11-13 machine generated eng FR FR-2025-11-13 90 217