California Moves to Expand Proposition 65 PFAS Listings

On Oct. 30, the California Office of Environmental Health Hazard Assessment (OEHHA) announced its intent to add three per- and polyfluoroalkyl substances (PFAS), specifically three perfluorinated carboxylic acids and related salts to the Proposition 65 list of chemicals known to the state to cause reproductive toxicity: 

• Perfluorobutanoic acid (PFBA) and related salts, based on developmental, male reproductive, and female reproductive endpoints
• Perfluorohexanoic acid (PFHxA) and related salts, based on developmental toxicity
• Perfluorodecanoic acid (PFDA) and related salts, based on developmental, male reproductive, and female reproductive endpoints

OEHHA is proposing the listings through Proposition 65's authoritative bodies mechanism under 27 CCR § 25306, based on conclusions made by the U.S. Environmental Protection Agency (EPA) regarding the potential toxicity of these chemicals. The public comment period runs through Nov. 30.

Why it matters

Manufacturers, importers, and downstream sellers will need to assess whether PFBA, PFHxA, or PFDA may be present in their products or manufacturing processes and whether resulting exposures could trigger Proposition 65 warning requirements if the listings are finalized. Importantly, the presence of a listed chemical does not automatically mean that a warning is required; listing reflects a chemical's hazard, whereas warning requirements depend on the level of exposure (e.g., whether exposure exceeds an applicable safe harbor level). Companies can evaluate the nature and magnitude of potential exposures to determine whether a warning or other risk-management measure is appropriate. 

For manufacturers, this assessment may extend beyond substances that are intentionally added to a product. PFBA and PFHxA are often considered "short chain" PFAS (i.e., perfluoroalkyl carboxylic acids with fewer than seven perfluorinated carbons) that could potentially occur as impurities, residuals, byproducts, or degradation or transformation products associated with other fluorinated substances, raw materials, processing aids, or manufacturing processes still used today. Accordingly, supplier declarations focused only on intentionally added PFAS may not be sufficient to characterize potential exposure under Proposition 65. The lack of standardized methods for detecting and quantifying these substances can present additional challenges.

The presence of these PFAS may also trigger different obligations in other jurisdictions, some of which focus on chemical content rather than exposure. For example, the European Union restriction on PFHxA, its salts, and PFHxA-related substances (e.g., 6:2 fluorotelomer alcohol [6:2 FTOH]) establishes concentration limits for certain products and uses, including 25 ppb for the sum of PFHxA and its salts and 1,000 ppb for the sum of PFHxA-related substances. Broader PFAS reporting and risk-management frameworks are also developing under U.S. TSCA and Canada's CEPA, as well as several U.S. states.

Companies with complex or multi-tiered supply chains can integrate proactive Proposition 65 assessments within a broader PFAS compliance strategy. Before simply adding a warning, companies may need to determine why the PFAS is present, whether its presence is intentional or incidental, whether it can be eliminated or controlled through manufacturing or supplier changes, the magnitude of possible consumer exposure, and whether the same concentration creates reporting, restriction, or prohibition issues in other markets.