California Proposition 65 California’s Proposition 65 Proposition 65 refers to the California Safe Drinking Water and Toxic Enforcement Act of 1986, a California law that requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm. These chemicals can be in the products that Californians purchase in their homes or workplaces, or that are released into the environment. By requiring that this information be provided, Proposition 65 enables Californians to make informed decisions about their exposures to these chemicals. Prop 65 requires a warning label added to any product that potentially contains any listed chemical, even at extremely low levels. <br/><br/> There are over 1,000 synthetic and naturally occurring chemicals on the Proposition 65 list, which is administered by California's Office of Environmental Health Hazard Assessment. Proposition 65's warning standards are among the most stringent in the world and California residents see Prop 65 warnings on a wide variety of products they purchase every day. <br/><br/> Proposition 65 is not a safety law but rather a ''right-to-know'' law.