Liver-cell tumours in rats fed hexachlorobenzene.

All animals in a group of female Agus rats fed 100 ppm of hexachlorobenzene (HCB) in their diet for up to 90 weeks developed multiple liver-cell tumours whereas none were seen in control rats. There was no evidence of skin lesions or nervous symptoms usually seen with higher doses of HCB. A high incidence of liver-cell tumours was also seen with MRC Wistar female rats fed HCB for 75 weeks.