What is California’s Prop 65?

What Proposition 65 requires

California Proposition 65, formally the Safe Drinking Water and Toxic Enforcement Act of 1986, requires businesses to warn Californians before knowingly causing significant exposure to a listed chemical. It also prohibits knowing discharges of listed chemicals into drinking-water sources. The list covers chemicals associated with cancer, birth defects, or other reproductive harm and is updated as scientific and regulatory decisions evolve.

Does every listed chemical require a warning?

No. A chemical’s presence alone does not automatically mean a warning is required. A business must evaluate the reasonably anticipated exposure and determine whether it is below an applicable safe-harbor level or otherwise exempt. If it cannot support that conclusion, a clear and reasonable warning may be necessary. Businesses with fewer than 10 employees are generally exempt, although other responsibilities can still arise through supply-chain relationships.

Prop 65 led many manufacturers to reformulate products or add warnings. Earlier generic warnings, such as language stating that a product “contains chemicals known to the State of California,” were widely used. Those older examples should not be copied without reviewing today’s warning rules, the exposure route, and the product’s sales channels.

Recent updates to Prop 65

OEHHA’s amended short-form warning rules took effect January 1, 2025. Businesses using the former short-form safe-harbor language have a three-year transition period, ending December 31, 2027. The amended short form generally identifies at least one listed chemical. Online and catalog warnings must also be coordinated with the product warning. In 2026, companies should verify chemical data, exposure assumptions, label space, ecommerce displays, and retailer notices well before the transition ends.

How Nexreg can help

Nexreg can review formulations and product information, assess warning requirements, and develop compliant Proposition 65 label language. Contact Nexreg before placing or revising a product on the California market.