US: The Office of Environmental Health Hazard Assessment (OEHHA) in California has asserted that polystyrene is not the same as styrene and is not listed by the state as a substance that causes cancer. The OEHHA has added styrene to a list of a list of chemicals known to the state to cause cancer for purposes of the Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65).
"There is sufficient scientific information to demonstrate that the intended uses of these materials are safe,” said the OEHHA. "While free or unreacted styrene may be present in such products, only styrene exposures that pose a significant cancer risk would require a warning." Styrene is used to make expanded polystyrene (EPS) but the substances have different properties. The OEHHA's listing is based on the findings of the 12th edition of the National Toxicology Program's Report on Carcinogens that assesses the potential for risks associated with styrene, primarily in work environments where levels of styrene exposure may be higher.
