Bisphenol S (BPS)

Bisphenol S (BPS) is an analogue of bisphenol A used as a BPA substitute in plastics, thermal papers, and personal care products. On January 28, 2025, California’s Developmental and Reproductive Toxicant Identification Committee (DARTIC) voted 9 to 0 to list Bisphenol S as a reproductive toxicant (male reproductive endpoint) under Proposition 65. Following the DARTIC vote, OEHHA proceeds to formally add the chemical to the Proposition 65 list, typically within approximately one year of the committee vote. Once listed, a warning would be required for exposures above the applicable Maximum Allowable Dose Level (MADL), which OEHHA has not yet established for BPS as of April 2026.

DARTIC meeting January 28, 2025 (vote 9-0 in favour of listing BPS); OEHHA p,p’-bisphenol chemicals review (October 21, 2025); California Health & Safety Code §25249.8.

Manufacturers and importers of products containing BPS — including thermal paper, BPA-free plastics, food contact materials, and cosmetics — should closely monitor OEHHA’s formal listing process for BPS. Once formally listed, they will have 12 months from the listing date to comply with warning requirements if exposure exceeds the applicable MADL. Companies that reformulated away from BPA to BPS should immediately begin assessing BPS exposure levels in their products.