Proposition 65

Prop 65 is a right-to-know law. The list of chemicals is kept by the Office of Environmental Health Hazard Assessment (OEHHA), part of California's environmental protection agency, and is updated regularly. Chemicals reach the list through several routes, including findings by authoritative scientific bodies.

The law does not ban chemicals. It requires a warning before a knowing exposure to a listed chemical unless the business can show the exposure is low enough to be exempt. To help with that, OEHHA publishes safe harbor levels for many listed chemicals: No Significant Risk Levels (NSRLs) for carcinogens and Maximum Allowable Dose Levels (MADLs) for reproductive toxicants. Not every listed chemical has one, and the rules on warning wording and delivery have been revised over time.

The warning may be placed on a product label, a shelf sign, a website, or a posted workplace notice. Employers in California can also meet the requirement for workers through posted warnings and hazard communication training.

Enforcement is unusual. In addition to the Attorney General, district attorneys and some city attorneys, private parties can bring actions in the public interest after serving a 60-day notice of violation, which is why many products sold nationwide carry a Prop 65 warning even when sold outside California. A warning does not by itself mean the product is dangerous at normal use, and its absence does not mean no listed chemicals are present.

For safety managers, the key is awareness: check whether chemicals in your products or processes appear on the current list, and understand that the list and safe harbor levels change.