PREVALENCE OF SMALL OPACITIES IN CHEST RADIOGRAPHS OF NICKEL SINTER PLANT WORKERS

Radiographs from 745 nickel sinter plant workers were taken and classi fied by five readers using the International Labour Office (1980) prot ocol. Each reader worked independently and the films were randomly mix ed with films from a non-dust exposed office population and also with films from subjects known to have silicosis or asbestosis. The prevale nce of small irregular opacities was selected as the outcome of intere st. In the sinter workers this was within the range identified in ciga rette smokers or in workers exposed to dusts of low fibrogenicity. Onl y minimal evidence of small round opacities was noted. There was no ev idence from the chest radiographs that exposures to high concentration s of dusts containing compounds of nickel caused an inflammatory or fi brogenic response in the lungs of the exposed population.