ALEXANDRIA, Va.— In a move that could have implications for eyeglass lens manufacturers, the State of California has relisted Bisphenol A (BpA) on its Proposition 65 list of potentially hazardous substances. The chemical is used in the manufacture of polycarbonate eyeglass lenses as well as in many non-optical products. It is known to cause cancer, birth defects or reproductive toxicity, according to California state officials.

The Prop 65 warning requirement for BpA, announced by California on Monday, takes effect after one year. Companies will have until May 11, 2016 to determine if their products sold in California contain BpA, or if employees at California workplaces that use the products will be exposed to BpA.

The American Chemistry Council and others have filed a lawsuit that seeks to block an earlier attempt by California to list BpA as a substance regulated under Proposition 65, which has been a California state law since 1986. The law regulates the presence of certain chemical substances found in products sold in California, or present in the workplace in California. If a business sells a product in California containing a substance or substances that are on the Proposition 65 list in excess of the minimum level for that substance, then a "clear and reasonable" warning must be provided to the public. The same applies for environmental or workplace exposures to Proposition 65 substances in California.

The Vision Council said in a statement yesterday that it is reviewing the new listing and will advise its members of any new development. In particular, The Vision Council is working to determine whether or not California is providing a safe harbor level for BpA. If a product contains BpA but in an amount that is below the safe harbor level, the manufacturer would not have to issue a warning about that product.