In their paper updating a previous investigation of the mortality of workers employed at a factory producing chemicals in North Wales, Sorahan, Hamilton, and Jackson plead for priority to be given for studies on the cancer experience of other working populations exposed to N-phenyl-β-naphthylamine (PBN).1

It is, therefore, disappointing that the authors made no reference at all to studies conducted by the British Rubber Manufacturers' Association (BRMA), and others, on rubber workers employed after 1950. These workers would have been exposed to PBN, and to other antioxidants still in use after the discontinuance (in 1949) of Nonox “S” and similar compounds contaminated by β-naphthylamine (BNA). This contaminant, a potent human bladder carcinogen, was at a concentration (2500 ppm) sufficient to double the incidence of bladder cancer in those exposed.

A particular study2 …

Dr T Sorahan

Dr T Sorahan