High Quality Content by WIKIPEDIA articles! Proposition 65 (formally titled "The Safe Drinking Water and Toxic Enforcement Act of 1986") is a California law passed by direct voter initiative in 1986 by a 63%-37% margin. Its goals are to protect drinking water sources from toxic substances that cause cancer and birth defects and to reduce or eliminate exposures to those chemicals generally, for example in consumer products, by requiring warnings in advance of those exposures. It is administered by Cal/EPA`s California Office of Environmental Health Hazard Assessment (OEHHA). Proposition 65 regulates substances officially listed by California as causing cancer or birth defects or other reproductive harm in two ways. The first regulatory arm of Proposition 65 prohibits businesses from knowingly discharging listed substances into drinking water sources, or onto land where the substances can pass into drinking water sources. The second regulatory arm of Proposition 65 prohibits businesses from knowingly exposing individuals to listed substances without providing a clear and reasonable warning.