Pulmonary fibrosis from amorphous silica dust, a product of silica vapor

After prolonged occupation exposure to amorphous silica dust-a product of vaporized crystalline silica (quartz)-eleven out of forty workers showed reticular and/or nodular abnormalities in roentgenograms of the chest. From this group, we present three illustrative cases. These had widespread pulmonary disease with granulomatous nodules and fibrosis (documented histologically in two cases), but there was no demonstrable restrictive impairment of pulmonary function. We discuss the possible importance of this previously underestimated toxicity, especially in an industrial setting.