The incidence of bladder tumours in a dyestuffs factory.

The incidence of bladder tumours in workers in the dyestuffs industry was first described by Rehn in 1895 and 1906. Leuenberger reported 41 cases in 1912, and by the third decade of this century in Europe exposure to beta naphthylamine and to benzidine had been accepted as a cause of bladder tumours by Kennaway (1924), Berenblum and Bonser (1937), Goldblatt (1949), and Muller (1951). In the U.S.A. Gehrmann, Foulger, and Fleming (1949) are less certain of the carcinogenicity of benzidine than the European investigators and have suggested that it cannot be accepted as a bladder carcinogen until it is known that benzidine workers without any exposure to beta naphthylamine have developed tumours of the bladder. This paper describes 23 cases of papilloma and carcinoma of the bladder among workers exposed only to benzidine, and reviews in all 66 cases not previously reported of confirmed bladder tumours arising in a dyestuffs factory. Fifty-eight cases were found in the section where intermediates are manufactured and eight in the colour factory where the intermediates are handled. No cross transfers have taken place and the populations have remained distinct. Only the men for whom data are complete have been included in this series. In addition there are 11 former employees believed to have died of bladder tumour whose histories are not yet fully traced, and two men reported to have developed tumours with whom contact has been temporarily lost. A voluntary system of compensation, by ex gratia payments, should help to ensure that the histories of men who develop tumours after leaving the factory will be known.