Vertical 03
Prop 65 / BPS — Consumer Safety
California's Safe Drinking Water and Toxic Enforcement Act of 1986 (Prop 65) requires warnings for exposures to listed chemicals above OEHHA-derived thresholds. With OEHHA's December 2024 listing of Bisphenol S as a reproductive toxicant, this vertical now extends to thermal-receipt and consumer-product investigations under a NIST IR 8387-aligned protocol.
1. Scope of the vertical
The vertical concentrates on two categories where chain-of-custody is decisive and where dermal-transfer modeling is well-established: thermal receipts (BPS) and consumer-product surface coatings (BPA/BPS and analogues). Investigations begin only after OEHHA listing of the relevant chemical and the running of the statutory clear-warning grace period.
2. Chain of custody (NIST IR 8387)
Samples are acquired during normal-course transactions, sealed at the point of acquisition in a Mylar evidence sleeve, hashed against an investigator log, and transferred to the laboratory under a documented transfer record. The protocol is aligned to NIST IR 8387 (general guidance on cryptographic chain-of-custody for digital and physical samples).
No sample is unsealed between acquisition and the laboratory's intake desk; the laboratory's intake hash is recorded against the office's acquisition hash before any analysis begins.
3. Laboratory partner posture
Analysis is performed by an independent laboratory holding ISO/IEC 17025 accreditation for the relevant analyte. The laboratory partner is named in every published report, and the laboratory's standard operating procedure is cross-referenced in the report's methodology section.
4. Dermal-transfer exposure assessment
Dermal-transfer exposure is modeled using the framework developed in Biedermann et al., Anal. Bioanal. Chem. 398:571 (2010), as adapted to OEHHA's BPS NSRL where applicable. The model is conservative on the transfer-efficiency parameter and is the same model relied on by major California Prop 65 enforcement matters.
5. Pre-suit 60-day notice
Where the investigation supports a Notice of Violation under Cal. Health & Safety Code § 25249.7(d), the office prepares a pre-suit memorandum documenting the chain of custody, laboratory analysis, exposure model, and the absence of a clear and reasonable warning. The notice itself is issued by counsel, not by this office.