The American Composites Manufacturers Assn. (ACMA, Arlington, VA, US) reports that the California EPA has listed styrene as a substance "known to the State to cause cancer" under Prop 65. Prop 65 regulation requires businesses that sell products in California to notify product users and consumers about potential health effects associated with use of their products. This means that if a business manufactures, distributes or imports products containing styrene that are sold in California, the manufacturer may have to provide toxicity warnings on those products.
The rule applies to any company that has manufactured a product containing styrene that is sold in the state of California, whether or not the company knew or intended for it to be sold in the state.
Manufacturers will have until April 2017 to determine if styrene exposures associated with use of their products are below the No Significant Risk Level (NSRL) for styrene, which the California EPA has proposed to set at 27 micrograms (ug) per day average lifetime exposure. If use-related exposures to styrene are below the NSRL, manufacturers will not need to provide a toxicity warning for that product. If those products are not below the NSRL, manufacturers must provide warnings labels to product users.
ACMA anticipated this ruling and put together a compliance program to help members of the composites supply chain. ACMA's Prop 65 Compliance Program has the guidance and tools to help members determine if the No Significant Risk Level exemption applies to their products. The tools include an ACMA report that describes the results of a study that measured the amounts of styrene and ethylbenzene contained in a range of composite products. It also estimates the amount of exposure product users and consumers had to those products.