EPA Invites Experts for Peer Review of Draft D4 Risk Evaluation

The U.S. Environmental Protection Agency (EPA) is inviting nominations of qualified scientists to serve as ad hoc peer reviewers for the draft risk evaluation of octamethylcyclotetrasiloxane (D4, CAS No. 556-67-2 ) under the Toxic Substances Control Act (TSCA). The peer review will be conducted by the Science Advisory Committee on Chemicals (SACC). 

Call for Nominations 

Areas of Expertise Sought 

Experts are sought in areas including:

• Human health hazard identification and risk assessment.
• Application of the D4 physiologically based pharmacokinetic (PBPK) model.
• Assessment of uncertainties in exposure and release.
• Evaluation of bioaccumulation, bioconcentration, biomagnification, and trophic transfer.
• Human fish consumption impacts, particularly for susceptible subpopulations.
• Ecological hazard identification and risk assessment.

Conflict of Interest Review 

Selected reviewers will be required to submit confidential financial disclosure forms. EPA will evaluate these to ensure there are no conflicts of interest or prior involvement in relevant scientific analyses. 

Selection and Public Meeting 

EPA will select reviewers with a view to both expertise alignment and balanced representation of diverse scientific viewpoints 

The peer review will take place during a virtual public meeting in December 2025. EPA will announce the official meeting dates soon. 

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