The pathogenicity of mixed dust from a fluorite mine was studied by animal experiments and in vitro tests. Animal experiments showed that calcium fluorite can induce only a foreign body reaction in the lungs; the fibrous nodular lesions induced by the fluorite mine dust are due mainly to its silica component. It was demonstrated that either silica or the mixed dust of a fluorite mine can stimulate pulmonary alveolar macrophages (PAMs) to release fibrogenetic factors in vitro, but calcium fluorite cannot. It was also demonstrated that having engulfed calcium fluorite, silica, or fluorite mine mixed dust, PAMs release an elastase-active substance. The authors suggest that the emphysematous lesion seen in autopsy material of pneumoconiosis of fluorite mine workers may be caused by calcium fluorite and silica.