According to Wikipedia: "[California] Proposition 65 (formally titled "The Safe Drinking Water and Toxic Enforcement Act of 1986") is a California law that has been in effect since 1986 to promote clean drinking water and keep toxic substances that cause cancer and birth defects out of consumer products. It is administered by Cal/EPA's California Office of Environmental Health Hazard Assessment (OEHHA).
Proposition 65 regulates substances 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. Since enactment, Proposition 65 has been the reason for the addition of notices of specific contents to consumer product labels.
Along with the added label requirements, an official list of implicated substances is maintained and made publicly available. Entries are added or removed based on current scientific information. All substances listed show their known or suspected risk factors, a unique CAS chemical classification number, the date they were listed, and if so, whether they have been delisted."
[SIDEBAR: This law is the law that is behind a warning tag that was attached to a hair-care appliance that I recently purchased. The hair appliance's warning tag alerted that the power cord "contains lead, a chemical known to the State of California to cause birth defects or other reproductive harm. Wash hands after handling."
I'll be expanding on this in a blog post later today.]