1,3-Propane sultone is directly alkylating, genotoxic and carcinogenic. In rats, it induces local and systemic tumours at multiple target sites. Preponderant systemic tumours occur at the central nervous system, especially gliomas. Other localisations include the mammary gland, the intestine, the haematopoietic system and the kidneys. In the German chemical industry, 1,3-propane sultone had been manufactured and used in limited amounts in the 1950s and 1960s, and for a very few purposes until the 1970s. The number of persons in contact with the compound is unknown but was limited. The medical history of some cases could be traced. As cerebral gliomas are the main systemic tumours induced by 1,3-propane sultone experimentally, the occurrence of a glioblastoma among previously exposed persons appears conspicuous. Three intestinal malignancies were recorded among the cases observed. Also noteworthy is one case of a duodenal carcinoma, normally a rare human malignancy. Two haematopoietic/lymphatic malignancies of different nature have been observed, and there was one case of a renal cell carcinoma. These malignancies observed within a group of persons exposed to 1,3-propane sultone appear surprisingly consistent with the expectations from the available animal studies. The present case studies point to long latency times (up to 30-40 years or more) after limited periods of past exposure.