Committee advances Chris Thayer�27s OEHHA nomination after extended questions on PFAS, modeling and Prop. 65

The Senate Rules Committee voted 3-1 to advance Chris Thayer, PhD, as director of the Office of Environmental Health Hazard Assessment (OEHHA), after an extended exchange about scientific methods, real-world monitoring and regulatory communication.

Thayer opened by summarizing a 30-year career in environmental health and said OEHHA27s role is to translate science into actionable information "that helps protect people and the environment," emphasizing transparency, scientific rigor and community engagement.

Why it matters: Several senators pressed Thayer on the agency27s use of modeled or indirect data rather than on-the-ground exposure monitoring. Sen. Grove asked why OEHHA relies on models when, she said, real-world fence-line monitoring or studies (for example, PFAS in fish) are available. Thayer responded that OEHHA aims to use direct data when it exists but that the field increasingly relies on alternative data and modeling because direct toxicology or human-health studies are lacking for many chemicals; she urged transparent methods, clear communication of uncertainty and peer review.

PFAS and real-world data were a focal point. Thayer acknowledged robust health characterization exists for some PFAS but said the chemical class includes thousands of compounds with limited data, necessitating read-across and inference in some cases. She cited ongoing efforts to prioritize research gaps and noted OEHHA27s work on the California Biomonitoring Program as an example of real-world measurement.

The committee also discussed CalEnviroScreen (the environmental justice screening tool), with Thayer noting a draft of the fifth iteration would be released for public review and that the analysis uses census-tract data (2020) to be more granular than earlier versions. Members asked about whether socioeconomic inputs (including housing costs) were included; Thayer said updates and outreach would accompany the draft release.

On Proposition 65 (Prop. 65), Thayer described OEHHA27s role in providing scientific guidance and acknowledged concerns about over-warning. She said OEHHA has conducted workshops for businesses, created information-letter regulations and issued safe-harbor levels and safe-use determinations to reduce unnecessary warnings; she also described outreach and an ombudsperson to help businesses comply.

Public comment: Environmental and public-health organizations, including the Environmental Working Group and Breast Cancer Prevention Partners, urged the committee to confirm Thayer, praising her federal experience and calling for strong state scientific leadership on PFAS and chemical risks.

Committee action and outcome: Sen. Laird moved to forward the nomination to the full Senate. The roll call recorded Limon aye, Grove no, Jones not voting, Laird aye and Reyes aye; the motion passed 3-1 and the nomination will proceed to the full Senate.