Proposition 65 (Safe Drinking Water and Toxic Enforcement Act of 1986)

Proposition 65 (formally the Safe Drinking Water and Toxic Enforcement Act of 1986) is a California voter initiative (Ballot Initiative, November 4, 1986) codified at California Health & Safety Code §25249.5 et seq. It requires: (1) businesses with 10 or more employees to provide a ‘clear and reasonable’ warning before knowingly exposing any person to a listed chemical above the safe harbour level; and (2) businesses to refrain from knowingly discharging listed chemicals into drinking water sources. As of April 2026, there are approximately 900 chemicals on the Proposition 65 list. The law is enforced by the California AG, district attorneys, city attorneys, and private enforcers. It applies to products sold or exposures occurring in California.

California Health & Safety Code §§25249.5–25249.13 (Proposition 65 statute); OEHHA Title 27 CCR (implementing regulations).

Proposition 65 applies to any business with 10 or more employees that sells products or causes exposures in California — regardless of where the business is located. Non-California businesses that sell products through e-commerce or retail into California must comply. The law requires affirmative action (warning provision) rather than just product reformulation. The most practical compliance approach for most businesses is: (1) identify listed chemicals in products; (2) assess exposures against safe harbour levels; (3) implement compliant safe harbour warnings where exposures exceed thresholds; and (4) maintain documentation.