A case of silicosis and progressive massive fibrosis with uncertain occupational exposure to silica

A case of histologically diagnosed silicosis with progressive massive fibrosis (PMF) and low dust exposure is reported. Two experienced occupational medicine practitioners took a detailed exposure history on three occasions. The only reported dust exposure was indirectly from coalcarrying conveyor belts in a power station for 23 years; where he worked as a clerk. The chest radiographs showed features consistent with PMF in 1994; after only 11 years of indirect dust exposure. Two pathologists independently reported PMF. The case demonstrates that even when heavy exposure is thought to be required to produce an occupational disease; the source of exposure may be difficult to ascertain