ToxStrategies has decades of experience helping clients and their legal teams navigate Proposition 65 requirements and litigation. As a trusted leader in Proposition 65 consulting with California-based staff, our team includes toxicologists who determine safe harbor levels, exposure scientists skilled in human-use exposure simulations, and experts who routinely evaluate chemical exposures through the air, skin, and food. We bring scientific clarity and practical insight to help clients achieve compliance and confidently manage risk.
ToxStrategies has extensive experience supporting clients with Proposition 65 evaluations across a wide range of applications, including:
- Air emissions
- Household consumer products
- Industrial and building materials
- Medical devices
- Food, beverages, and food-contact materials
- Cosmetics and personal care products
- Workplace and environmental exposures
Our Capabilities
Toxicology
- Derivation and evaluation of safe harbor levels (NSRLs/MADLs)
- Benchmark dose and dose-response modeling
- Physiologically Based Pharmacokinetic (PBPK) modeling
- Mode-of-action (MOA) analyses and weight- ofevidence (WOE) assessments
- Cancer potency and reproductive toxicity analysis
- Margin of Exposure (MOE) derivation and interpretation
Exposure Assessment
- Design of product-specific exposure simulations consumer-use studies
- Food-contact migration and exposure assessments
- Evaluation of workplace and environmental exposure pathways
- Screening exposure assessments of multiple products and multiple product lines to focus on products that may require warnings
Legal and Compliance Support
- Preparation of expert opinions and supporting documentation for legal counsel
- Review of 60-day notices and assistance with response strategy
- Development of exposure-based defense materials for settlement negotiations
- Evaluation of “clear and reasonable” warning obligations and compliance strategies
- Identification of potential sources of Proposition 65-listed substances in formulations or raw materials
Regulatory and Listing Support
- Preparation and technical review of comments for OEHHA Chemical Identification Committee (CIC) and Developmental and Reproductive Toxicant Identification Committee (DARTIC) meetings
- Evaluation of draft hazard and listing documents for scientific accuracy and consistency with Proposition 65 criteria
- Support for chemical listing or delisting petitions
- Assessment of toxicological data for alignment with IARC, NTP, and OEHHA listing frameworks
- Interpretation of OEHHA guidance, regulations, and updates relevant to product compliance
Case Study #1: Proposition 65 Risk Assessment of Worker Exposure to Chemicals in Lubricants and Specialty Fluids
ToxStrategies conducted a worker exposure assessment for hundreds of lubricant and specialty fluid products to evaluate compliance with notification requirements under Proposition 65. The team screened formulations to identify Proposition 65-listed chemicals and then identified or derived safe harbor levels for each chemical. Screening-level concentrations were established to determine thresholds below which a Proposition 65 warning would not be required. The screening levels were based on a very generic industrial exposure scenario, and the comparison resulted in a subset of products and chemicals for which generic exposure exceeded safe harbor levels. Actual product use was researched for categories of products, and more specific exposure scenarios were developed that represented more likely worker exposures. The predicted exposures were compared to Proposition 65 safe harbor levels to identify any products that would require notification labels.
Case Study #2: Proposition 65 Risk Assessment of Exposure to Lead and Cadmium in Food
Following our client’s receipt of a 60-day notice, ToxStrategies was asked to evaluate potential exposure to lead and cadmium in a food product. Representative concentrations of each metal were measured in the product, and ToxStrategies researched potential daily consumption using a variety of sources. Because lead and cadmium both have developmental effects (in addition to cadmium being listed for carcinogenic effects), the evaluation focused on a reasonable anticipated daily exposure. In addition to serving size information, the average intake rate considered public food consumption datasets, such as the U.S. Department of Agriculture’s Home Economic Research Report, Foods Commonly Eaten by Individuals: Amount Per Day and Per Eating Occasion. ToxStrategies’ report was used by the attorneys to negotiate a more favorable settlement on behalf of the client.
Case Study #3: Environmental Exposure Assessment of Metals
ToxStrategies evaluated potential exposure to metal emissions from a metal finishing facility. Air dispersion modeling was performed to estimate off-site concentrations of various metals, and exposure was estimated for residents and workers in the area. Average daily exposures were compared to safe harbor levels to identify whether an environmental warning was required under Proposition 65. Proposition 65 warnings were placed at the facility’s perimeter to provide warnings to persons visiting the facility.
Case Study #4: Notification Guidance
ToxStrategies developed specific written guidance for a property manager to provide to their tenants regarding compliance with Proposition 65 warning regulations. In some cases, the tenants were part of the property manager’s operations, and in other cases, independent businesses operated within the property manager’s buildings. The California Office of Environmental Health Hazard Assessment (OEHHA) has established guidelines for specific businesses, types of exposures, and products. After reviewing the types of tenants leasing properties, ToxStrategies created written guidelines for the property owner to provide to the tenants that simplified the compliance process. For example, some of the properties were leased as restaurants, and ToxStrategies provided guidance that addressed the notification requirements for alcoholic beverages and Proposition 65-listed chemicals in food (e.g., mercury in fish). Ultimately, ToxStrategies developed guidelines for five types of tenants to support the property manager’s operations.
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