California’s Proposition 65 (Prop. 65), officially known as the Safe Drinking Water and Toxic Enforcement Act of 1986, requires the State to maintain and update a list of chemicals known to the State to cause cancer or reproductive toxicity. In addition, manufacturers, formulators, and suppliers of products that contain these substances must provide a clear and reasonable warning to persons that can be exposed to these chemicals unless the exposure is low enough to pose no significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm. A common misconception is that there is a de minimis concentration below which the presence of the chemical in the product would negate the need for a warning, but this is not the case. If a listed chemical is present, the warning is required unless it can be demonstrated, through a Safe Use Determination (SUD), that exposure to the chemical would be below the Safe Harbor Level, typically expressed as micrograms (µg) of exposure per day resulting from inhalation, dermal, and oral routes combined. This means that not only is it important to consider the intended chemical ingredients of a product, but also impurities that may be present in the raw materials or that may form as the product ages.

The California Attorney General’s Office enforces Proposition 65, as can any district attorney or city attorney (for cities whose population exceeds 750,000). In addition, any individual acting in the public interest may enforce Proposition 65 by filing a lawsuit against a business alleged to violate this law. As such, lawsuits have been filed by the Attorney General’s Office, district attorneys, consumer advocacy groups, and private citizens and law firms. As a result, even well-meaning companies can easily get caught up in expensive litigation. In addition, large retailers like Walmart, Amazon, Target, and Auto Zone are increasingly asking suppliers to certify compliance with Prop. 65.

Experien Health Sciences has the regulatory, toxicology, and exposure assessment experts to help product manufacturers and suppliers:

  • Identify which of their products contain (or may contain) Prop. 65 chemicals, and which warnings apply.
  • Conduct Safe Use Determinations (SUD) for products where a Prop. 65 warning would have a negative impact in the marketplace, including initial Tier 1 screening level assessments and following that up with a more detailed Tier 2 assessments when desired.
  • Advise clients on strategies for reformulating products to eliminate the need for Prop. 65 warnings.
  • Review product labeling to ensure it conforms to Prop. 65 warning requirements.


Learn more about how Experien Health Sciences can help you with California Prop. 65 Services