Cancer of respiratory organs among workers at a nickel refinery in Norway

Abstract A follow‐up study has revealed a clearly increased incidence of cancer of respiratory organs among men employed at a nickel refinery in Norway. During the period 1953–71 there were 48 cases of lung cancer, 14 cases of cancer of nasal sinuses and 5 cases of laryngeal cancer. The highest risk was among men involved in roasting, smelting and electrolysis. For these men the ratio of observed to expected number of cases was 7:1 for lung cancer and 40:1 for cancer of nasal sinuses. Still higher relative risks were found for workers of these categories whose employment had started before 1940. The refinery, established in 1910, practically discontinued production when the war hit Norway in 1940. Production was resumed in 1945, and subsequently the processes have undergone major changes. Of the 14 cases of cancer of nasal sinuses only one has occurred among men whose first employment started after 1945, but as the induction time for this form of cancer was found to be very long in this material, it is still uncertain whether a reduction of the risk has been achieved. As regards lung cancer, it is clear that the hazard of exposure still persisted around 1950. Although it has not been practicable in this study to obtain information on smoking habits and on possible exposure in other occupations, it is concluded that the increased risk among the men is largely ascribable to exposure at the refinery. Deaths and cases of cancer among the men were identified by computer linkage of past and current employees against all deaths in Norway and against all cases of cancer reported to the Cancer Registry of Norway during the follow‐up period.