In 1986 the California voters approved an initiative called the Safe Drinking Water and Toxic Enforcement Act, due to their concerns of over exposure to toxins. This act is now known as Proposition 65 which is a law in California. This law requires the state to publish a list of chemicals, one list of chemicals known to cause cancer and another list known to cause birth defects or other reproductive harm. These two lists are updated once a year and the list has grown to well over 950 chemicals since it was published in 1987.
Proposition 65 warnings can be found all over California, including restaurants, amusement parks including Disney Land, work environments, parking lots, hospitals, rental properties, dental offices, schools and on many consumer products, including products that are 100% natural and have been certified organic. If a chemical is listed under Proposition 65 as a reproductive toxin or as a carcinogen and has been shown to cause developmental/reproductive toxicity or cancer in laboratory animals, the state of California is required to put those chemicals on the list, even if these chemicals have not been tested on humans.