Styrene

Styrene is a synthetic chemical listed under Proposition 65 as a carcinogen (listed April 6, 2012). OEHHA has established a No Significant Risk Level (NSRL) for styrene of 27 micrograms per day. Styrene is used as a monomer in the production of polystyrene plastics, ABS plastic, rubber, and various resins. In the context of electronics and consumer products, styrene-containing plastics (polystyrene, ABS) are widely used for housings, packaging, and components. Food packaging using polystyrene may also trigger Proposition 65 concerns if styrene migrates into food above the NSRL.

OEHHA Proposition 65 list (listed April 6, 2012); NSRL: 27 μg/day (27 CCR §25703).

Electronics manufacturers using ABS or polystyrene housings must assess whether styrene migration or exposure from their products exceeds the NSRL of 27 μg/day under normal use conditions. For most solid plastic housings where styrene is fully polymerised and sealed, exposure may be negligible. However, recycled or off-specification plastics with residual monomer content warrant closer attention. Food contact polystyrene applications require more rigorous styrene migration testing given the lower NSRL relative to potential migration levels.