An unusual case of mixed-dust exposure involving a "noncommercial" asbestos

Our health center evaluated an individual for suspected pneumoconiosis, whi ch had resulted from exposures in a foundry/metal reclamation facility. App ropriate consent forms were obtained for the procedures. Historically, indi viduals who work in foundries have been exposed to various types of dusts. The clinical findings in this case were consistent with silicosis with a su spicion of asbestos-induced changes as well. A sample from this individual, analyzed by electron microscopy showed both classical and atypical ferrugi nous bodies. The uncoated fiber burden in this individual indicated an appr eciable number of anthophyllite asbestos fibers. This finding, coupled with analysis of cores from ferruginous bodies and the presence of ferruginous bodies in areas of interstitial fibrosis, pathologically supported the diag nosis of asbestos-related disease. The unique factor associated with this c ase is that unlike in some settings in Finland where anthophyllite was mine d and used commercially, this mineral fiber is trot commonly found in comme rcially used asbestos products in the United States. Although the actual so urce of the asbestos exposure in this case is still bring sought, it should be recognized that anthophyllite is a contaminant of many other minerals u sed in workplace environments, including foundries. The fiber burden indica tes a unique type of exposure, differing from that usually construed as typ ical in occupational settings in the United States.