California Proposition 65, also known as the Safe Drinking Water and Toxic Enforcement Act of 1986, was created to protect California’s drinking water from contamination. California publishes a list of chemicals known to cause cancer, birth defects, or other reproductive harm, which is updated once a year. There are around 800 different chemicals currently, you can see a complete list on OEHHA, California Office of Environmental Health Hazard Assessment. Proposition 65 requires businesses to notify Californians about significant amounts of chemicals in the products they purchase, in their homes or workplaces, or that are released into the environment. By providing this information, Proposition 65 enables Californians to make informed decisions about protecting themselves from exposure to these chemicals.
Glasses and sunglasses may display the Prop 65 warning because of the Bisphenol-A (BpA) found in polycarbonate lenses. Bisphenol-A (BpA) is a starting material in the manufacture of polycarbonate, so there are trace amounts of BpA found in those lenses. Common consumer goods, such as water bottles and the coatings on the inside of many food and beverages are made with BpA. According to www.factsaboutbpa.org/, studies have consistently shown that the potential migration of BpA into food is extremely low, generally less than 5 parts per billion. Also consider that you will not be biting, drinking from, or otherwise ingesting your glasses lenses. In May, 2015, the state of California relisted (BpA) on the Prop 65 chemicals list.
The BpA found in polycarbonate lenses is in trace amounts. The use of polycarbonate for food contact applications continues to be recognized as safe by the U.S. Food and Drug Administration and other regulatory authorities worldwide. And you won't be eating your sunglasses.