Carcinogenicity of vinyl chloride in Sprague-Dawley rats after prenatal and postnatal exposure.

Vinyl chloride was administered by inhalation, 7 hours daily, 5 days weekly, at concentrations of 2500 and 0 ppm, to Sprague-Dawley rats. The treatment was started on 13-week-old breeders and male and female offspring (12-day embryos). The breeders and part of the offspring were exposed for 104 weeks; the other part of the offspring was exposed for 15 weeks only. Under the experimental conditions, vinyl chloride caused an exceptionally high incidence of brain neuroblastomas, liver angiosarcomas, and hepatocarcinomas. The age at start and/or length of treatment may affect the onset of these tumors in different ways.