Radiographic Evidence of Silicosis in Relation to Silica Exposure

Abstract

Abstract Although the risk of silicosis has long been recognized as a consequence of exposure to crystalline silica, there are only limited data available for quantitatively estimating risk in relation to modern concentrations. Reports on three large groups of workers (Vermont granite workers, South African gold miners, and Ontario hardrock miners) form the basis for estimating silicosis risk; two other smaller studies, of British gypsum miners and North Carolina dusty trades workers, provide additional but less quantitative information. For 40 years of exposure to a respirable silica concentration of 0.1 mg/m3, the estimated cumulative risk of radiographic evidence of silicosis is approximately 1 to 3 percent based on the Ontario miners (depending on whether diagnosis requires a positive reading by a majority of five readers or by only one reader) and is 60 percent based on South African miners. Findings from Vermont granite workers and North Carolina dusty trades workers are more consistent with the low...