Proposition 65

Proposition 65 Compliance: Simplified, Defensible, and Strategic

Navigating California’s Prop 65 requirements can be complex and costly. RHP Risk Management helps companies confidently evaluate exposure risks, determine when warnings are necessary, and implement compliant, defensible solutions backed by rigorous science and regulatory expertise.

Proposition 65, formally the Safe Drinking Water and Toxic Enforcement Act of 1986, establishes a list of chemicals “known to have carcinogenic, teratogenic, or reprotoxic effects.” Since the list was first published in 1987, California has updated it regularly, and it now includes approximately 900 chemicals.

Once a chemical is added to the Prop 65 list, the Office of Environmental Health Hazard Assessment (OEHHA) may establish “safe harbor” exposure levels. For cancer-causing chemicals, these are called No Significant Risk Levels (NSRLs), and for chemicals that may cause reproductive harm, they are called Maximum Allowable Dose Levels (MADLs). These values indicate exposure levels below which no warning is required.

Manufacturers, importers, distributors, and retailers selling products in California must determine whether exposures to listed chemicals exceed established safe harbor levels, and if so, provide “clear and reasonable” warnings. Meeting these requirements depends on reliable exposure data, sound scientific analysis, and well-documented, defensible conclusions.

RHP combines expertise in exposure science, toxicology, and epidemiology to evaluate potential risks, characterize exposures under real-world conditions, and support compliance decisions that align with regulatory expectations and business objectives.

How RHP Supports Prop 65 Compliance

Exposure Assessment

We quantify real-world exposures through advanced laboratory testing and modeling to produce accurate, defensible data. RHP’s in-house Exposure Sciences Laboratory (ESL) provides the unique capability to conduct both real-world testing and exposure simulations.

Hazard and Risk Characterization

RHP integrates toxicological and epidemiological data to evaluate potential hazards and assess risk. We determine whether exposures exceed OEHHA safe harbor levels (NSRLs and MADLs) and provide scientifically robust, defensible conclusions. When safe harbor levels are unavailable, RHP can derive appropriate values consistent with current risk assessment best practices and regulatory considerations – enabling clients to proactively assess their products ahead of formal guidance.

Regulatory Strategy and Compliance Decision-Making

RHP translates scientific findings into clear, practical compliance strategies, whether that means no warning required, product reformulation, exposure controls, or implementing warnings. We also provide thorough documentation designed to support regulatory review and legal scrutiny.

Labeling, SDS, and Product Review

We evaluate product formulations, labeling, and safety data sheets (SDSs) to ensure alignment with Prop 65 and broader regulatory requirements (e.g., GHS/CLP), helping maintain consistency across markets.

Risk Reduction and Product Safety and Stewardship

When exposures exceed acceptable thresholds, we support practical risk management solutions, including reformulation strategies, engineering controls, and communication approaches that reduce liability while maintaining product performance.

Ongoing Regulatory Monitoring

Our team tracks developments from OEHHA, EPA, and TSCA to help clients stay ahead of evolving requirements and proactively manage compliance risks.

Prop 65 compliance requires more than screening-level assessments – it requires integration of multiple scientific disciplines to support defensible conclusions. By integrating across our health and human risk science disciplines, RHP develops transparent, reproducible assessments that support both compliance and litigation readiness.

What RHP Delivers

• Defensible exposure and risk assessments aligned with Prop 65 requirements.

• Clear determination of warning requirements based on NSRLs and MADLs.

• Product labeling and SDS evaluations for regulatory consistency.

• Risk management strategies, including reformulation and exposure controls.

• Scientific documentation designed for regulatory submissions and robust support in legal settings.

Contact RHP experts to reduce uncertainty and enable confidence in decision-making by delivering reliable, reproducible, and relevant data. Through early and active stakeholder engagement, we provide customized solutions that support clients with their specific goals.