Styrene: toxicity studies--what do they show?

Styrene is efficiently metabolized to styrene oxide, which is itself readily detoxified by the same enzymes as those involved in the metabolism of various foodstuffs. Styrene oxide, like many intermediate metabolites of foodstuffs, is genotoxic and, if introduced directly into the stomachs of rodents in high doses/concentrations, gives rise to cancers of the forestomach. Exposing mice to doses of styrene high enough to overwhelm the capacity of the body to detoxify styrene oxide has been reported to increase lung tumor incidence in mice. The findings in eight epidemiological studies provide reassurance that occupational exposure to styrene is not associated with increased cancer risk. Tests for reproductive toxicity have given negative results, but effects on blood dopamine and hypothalamic and pituitary function and menstrual cycling under conditions of very high exposure have been reported. In light of all the available information, it is concluded that migration of styrene from food-wrapping materials is not a matter for toxicological concern.