<NOTICE>
ENVIRONMENTAL PROTECTION AGENCY
<DEPDOC>[EPA-HQ-OPPT-2018-0443; FRL-12964-02-OCSPP]</DEPDOC>
<SUBJECT>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</SUBJECT>
<HD SOURCE="HED">AGENCY:</HD>
Environmental Protection Agency (EPA).
<HD SOURCE="HED">ACTION:</HD>
Notice; extension of comment period.
<SUM>
<HD SOURCE="HED">SUMMARY:</HD>
In the
<E T="04">Federal Register</E>
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.
</SUM>
<DATES>
<HD SOURCE="HED">DATES:</HD>
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.
</DATES>
<HD SOURCE="HED">ADDRESSES:</HD>
Submit your comments, identified by docket identification (ID) number EPA-HQ-OPPT-2018-0443, online at
<E T="03">https://www.regulations.gov</E>
. Follow the online instructions for submitting comments. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Additional instructions on commenting and visiting the docket, along with more information about dockets generally, is available at
<E T="03">https://www.epa.gov/dockets</E>
.
<FURINF>
<HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD>
<E T="03">For technical information:</E>
Scott Drewes, Existing Chemical Risk Management Division (7404M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460-0001; telephone number: (202) 564-8833; email address:
<E T="03">drewes.scott@epa.gov</E>
.
<E T="03">For general information on TSCA:</E>
The TSCA Assistance Information Service Hotline, Goodwill Vision Enterprises, 422 South Clinton Ave., Rochester, NY 14620; telephone number: (800) 471-7127 or (202) 554-1404; email address:
<E T="03">TSCA-Hotline@epa.gov</E>
.
</FURINF>
<SUPLINF>
<HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD>
To give stakeholders additional time to review materials and prepare comments, EPA is hereby extending the comment period established in the
<E T="04">Federal Register</E>
document of September 17, 2025, at 90 FR 44821 (FRL-12964-01-OCSPP) for 15 days, from November 17, 2025, to December 2, 2025. More information on the action can be found in the
<E T="04">Federal Register</E>
of September 17, 2025.
EPA provided a concurrent public comment period soliciting public comment on the draft documents and charge questions to be provided to the Octamethylcyclotetrasiloxane (D4); Draft Risk Evaluation; Science Advisory Committee on Chemicals (SACC) Peer Review; Notice of SACC Meeting; Availability of Draft Documents and Request for Comment (90 FR 45204, September 19, 2025) (FRL-12975-01-OCSPP), docket identification number EPA-HQ-OPPT-2025-1610. EPA is not reopening the peer review public comment period with this notice or delaying the SACC peer review meeting for D4. The opportunity to provide information to EPA via the Octamethylcyclotetrasiloxane (D4); TSCA Review docket (EPA-HQ-OPPT-2018-0443) on requested information will now continue through December 2, 2025.
To submit comments or access the docket, please follow the detailed instructions provided under
<E T="02">ADDRESSES</E>
. If you have questions, consult the technical person listed under
<E T="02">FOR FURTHER INFORMATION CONTACT</E>
.
<E T="03">Authority:</E>
15 U.S.C. 2601
<E T="03">et seq.</E>
<SIG>
<DATED>Dated: November 10, 2025.</DATED>
<NAME>Mary Elissa Reaves,</NAME>
Director, Office of Pollution Prevention and Toxics.
</SIG>
</SUPLINF>
<FRDOC>[FR Doc. 2025-19878 Filed 11-12-25; 8:45 am]</FRDOC>
</NOTICE>
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