In 1986, California voters approved the Safe Drinking Water and Toxic Enforcement Act known as Proposition 65. The purpose of Proposition 65 is to ensure that consumers are informed about exposure to chemicals known by the State of California to cause cancer, birth defects and/or other reproductive harm.
An annually updated list includes a variety of chemicals that can be found in common household products, food, drugs, tobacco products, pesticides, solvents, dyes, etc. Some of the chemicals can be used in manufacturing and construction or they can be byproducts of chemical processes.
The Proposition 65 warning is issued by companies who are aware or believe that one or more of the listed chemicals is present in their products. By law, a warning must be given for listed chemicals unless exposure is low enough to pose no significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm.
Some companies have chosen to provide a warning based on their knowledge about the presence of a listed chemical without attempting to evaluate the exposure. With Polar products, the exposure may be negligible or well within the “no significant risk” range. Polar has chosen to provide this notice as an abundant caution.
Information of Mechanisms for Listing and Delisting Chemicals Under Proposition 65: https://oehha.ca.gov/proposition-65/how-chemicals-are-added-proposition-65-list
More information about Proposition 65: http://www.oehha.ca.gov/prop65/background/p65plain.html