Proposition 65 is administered by Cal/EPA's California Office of Environmental Health Hazard Assessment (OEHHA).
Proposition 65 regulates substances officially listed by California as having a 1 in 100,000 chance of causing cancer over a 70-year period or birth defects or other reproductive harm in two ways.
The first statutory requirement 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 prohibits businesses from knowingly exposing individuals to listed substances without providing a clear and reasonable warning.
An official list of substances covered by Proposition 65 is maintained and made publicly available.
Chemicals are added to or removed from the official list based on California's analysis of current scientific information. All substances listed show their known risk factors, a unique CAS chemical classification number, the date they were listed, and, if so, whether they have been delisted.