On the occasion of a hitherto unique observation of three hepatocellular carcinomas in workers of the same industrial plant within 7 years following long-term exposure to vinylchloride, the characteristics are discussed of a chemical carcinogenesis leading to two different malignant tumours: haemangiosarcoma and hepatocellular carcinoma. This carcinogenic sequence has been predicted by animal studies. It is not known why the transformation of hepatocytes into carcinoma is far rarer than of sinusoidal cells into sarcoma. Whereas the hepatocellular carcinoma predominantly develops in association with cirrhosis, vinyl chloride is able to cause cancer directly without other known co-carcinogenic agents. This hepatic carcinogenicity is dose-dependent. After the introduction of industrial prevention measures, a new initiation of the tumour is improbable. Nevertheless, because of its long latency period, estimated between 5 and 20 years, clinical manifestations are still possible. An early diagnosis by sonography and computertomography, possibly combined with puncture, in exposed persons or those formerly at high risk is conceivable, while laboratory data, even tumour markers are unreliable. Its fulminant course does not differ from that of other hepatocellular carcinomas and has until now hindered successful treatment.