In an article published on May 15, 2017 regulatory news provider Chemical Watch reported that the Californian Office of Environmental Health Hazard Assessment (OEHHA) has adopted a No Significant Risk Level (NSRL) of 27 µg/day for styrene (CAS 100-42-5). In April 2016, OEHHA had added styrene to the Proposition 65 list of substances known to the state of California to cause cancer (FPF reported). The NSRL represents the safe harbor level below which no warning label regarding the exposure to styrene would be required on products under Proposition 65.

The industry group Styrene Information and Research Center (SIRC) had called for much higher safe harbor levels, Chemical Watch informed. However, OEHHA wrote in its Final Statement of Reasons (FSOR) that the levels proposed by SIRC “are not well supported by the underlying data.” The OEHHA further stated that “the levels of . . . residual styrene in polystyrene food packaging materials are generally thought to be fairly low in most cases” and “a warning for styrene would only be required in cases where . . . styrene exposures [are] greater than 27 µg/day.”

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Chemical Watch (May 15, 2017). “California adopts no significant risk level for styrene.

OEHHA (May 11, 2017). “Notice of amendment to section 25705, no significant risk level for styrene.

OEHHA (May 11, 2017). “Final statement of reasons – NSRL for styrene.(pdf)

OEHHA (2017). “Styrene.