title: Role of silica in progressive massive fibrosis. In coal workers' pneumoconiosis.
mesh_terms: D003032:Coal Mining; D004391:Dust; D006801:Humans; D011009:Pneumoconiosis / Q000209:etiology*; D011658:Pulmonary Fibrosis / Q000209:etiology*; D012822:Silicon Dioxide / Q000032:analysis*
chemical_list: D004391:Dust; D012822:Silicon Dioxide