A Proposition 65 warning informs consumers that the water they are drinking contains chemicals that are known to cause cancer, according to the Office of Environmental Health Hazard Assessment. A Proposition 65 warning does not mean that the product is in violation of safety requirements, however.
Proposition 65 was first introduced in 1986, according to the OEHHA. It was designed to protect Californian drinking water sources from having chemicals that cause cancer or other defects from being used without informing consumers about them. However, Proposition 65 does not prohibit the use of chemicals or restrict their use on a product. It is up to the consumers to decide if they want to use products that contain the warning. It also applies to food and nonfood products, such as building materials and automotive products. Proposition 65 also covers lead in jewelry. If a product exceeds the safety threshold for lead of 0.5 micrograms, then the business is required to provide a warning to customers.
Small businesses with fewer than 10 employees, government agencies and public water systems are not required to give warnings, states the OEHHA. The governor of California is required to publish an annual of the chemicals that are covered under Proposition 65.