Radiographic abnormalities and duration of employment in Western Australian iron-ore miners.

Plain chest radiographs of 788 Pilbara iron-ore miners from Western Australia have been examined by two independent observers for evidence of pneumoconiosis. The prevalence of any radiographic abnormality (a profusion grade of 0/1 or greater on the International Labour Office [ILO] scale) was 6.7% for Reader 1 and 9.9% for Reader 2. The prevalence of a definite radiographic abnormality (a profusion grade of 1/0 or greater on the ILO scale) was 1.9% for Reader 1 and 2.8% for Reader 2. The prevalence of any abnormality, as identified by either or by both observers, was significantly related to age. The relationship between a radiographic abnormality and the duration of employment was less clear. The results indicate a need for more detailed and comprehensive studies of the effects of iron-ore dust in this industry.