Prevalence of beryllium sensitization among aluminium smelter workers.

BACKGROUND Beryllium exposure occurs in aluminium smelters from natural contamination of bauxite, the principal source of aluminium. AIMS To characterize beryllium exposure in aluminium smelters and determine the prevalence rate of beryllium sensitization (BeS) among aluminium smelter workers. METHODS A population of 3185 workers from nine aluminium smelters owned by four different aluminium-producing companies were determined to have significant beryllium exposure. Of these, 1932 workers participated in medical surveillance programmes that included the serum beryllium lymphocyte proliferation test (BeLPT), confirmation of sensitization by at least two abnormal BeLPT test results and further evaluation for chronic beryllium disease in workers with BeS. RESULTS Personal beryllium samples obtained from the nine aluminium smelters showed a range of <0.01-13.00 μg/m(3) time-weighted average with an arithmetic mean of 0.25 μg/m(3) and geometric mean of 0.06 μg/m(3). Nine workers were diagnosed with BeS (prevalence rate of 0.47%, 95% confidence interval = 0.21-0.88%). CONCLUSIONS BeS can occur in aluminium smelter workers through natural beryllium contamination of the bauxite and further concentration during the refining and smelting processes. Exposure levels to beryllium observed in aluminium smelters are similar to those seen in other industries that utilize beryllium. However, compared with beryllium-exposed workers in other industries, the rate of BeS among aluminium smelter workers appears lower. This lower observed rate may be related to a more soluble form of beryllium found in the aluminium smelting work environment as well as the consistent use of respiratory protection.