A carcinogenicity study of styrene-7,8-oxide in rats.

Styrene-7,8-oxide (200 mg/kg body wt) was given orally to female BDIV rats on 17th day of pregnancy. Their offspring received 96 weekly doses of styrene oxide (100-150 mg/kg body wt). Following the continuous administration of styrene oxide, an increased incidence, statistically significant, of forestomach tumours was observed in rats of both sexes. The incidence of tumours occurring at other sites was similar in treated and control animals. The present results show that styrene oxide is a direct-acting carcinogen producing benign and malignant tumours of the forestomach.