Source: http://oehha.ca.gov/proposition-65/crnr/notice-emergency-action-amend-section-256033-title-27-california-code

In California, the Office of Environmental Health Hazard Assessment (OEHHA) is the state entity responsible for the implementation of Proposition 65.  OEHHA has the authority to adopt and amend regulations to implement and further the purposes of Proposition 65.  OEHHA maintains a list of chemicals known to cause reproductive toxicity or cancer.  Proposition 65 requires businesses to provide a warning when they knowingly and intentionally cause an exposure to a listed chemical, and prohibits the discharge of listed chemicals into sources of drinking water.

On May 11, 2015, bisphenol A (BPA) was added to the Proposition 65 list of chemicals known to cause reproductive toxicity based on the female reproductive endpoint.  Effective May 11, 2016, warnings are required for exposures to BPA unless the person causing the exposure can show that an exposure 1,000 times the level in question has no observable effect.  OEHHA is proposing to promulgate an emergency regulation to allow temporary use of a standard point-of-sale warning message for BPA exposures from canned and bottled foods and beverages. 

Proposition 65 is a right-to-know law based on the concept that members of the public have a right to know when they are being exposed to listed carcinogens or reproductive toxicants. A Proposition 65 warning is not a regulatory decision that a product is safe or unsafe.  Rather, the law is designed to help consumers decide whether to assume the risks of purchasing particular products that result in exposures to listed chemicals.