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Asbestos has been used in many applications, but possibly one of the more unique was in the manufacturing of filters for cigarettes. The type of asbestos used in this application was crocidolite. Data from several resources indicate that crocidolite was one of the least utilized types of commercial asbestos in the United States. The present study provides quantitative tissue burden analysis data for two mesothelioma cases where the work histories included manufacturing of cigarette filters that contained crocidolite. The data include the number of asbestos bodies and uncoated fibers per gram of tissue, as well as the dimensions of these structures. The conclusion of the findings indicates that the individuals had an appreciable homogeneous exposure to crocidolite asbestos.

It has been suggested that glass fibers in the respirable size range may pose a health hazard similar to asbestos because of the similarities in physical characteristics. To compare the pulmonary cell response with that described earlier with crocidolite asbestos, we administered a milled fiberglass sample to mice by intratracheal instillation. Little effect was seen at a dose of 0.1 mg, but at 1 mg there was epithelial injury and an inflammatory cell response concentrated at bronchiolar-alveolar duct regions. Cellular incorporation of tritiated thymidine showed that repair of both bronchiolar and alveolar epithelium occurred rapidly. This was followed by an extended increase in cell labeling, particularly in peribronchiolar fibroblasts, from 2 to 8 wk after fiber instillation. Granulomas formed at this site and later there was morphologic evidence of fibrosis, which was confirmed biochemically by a significant increase in lung collagen at 4-16 wk. Although 10 times higher dose is required, the results show that the lung response to fiberglass in this experimental system is similar to that described previously for crocidolite asbestos; the sites of cell injury and repair are the same, and the subsequent fibrotic response produces small airway disease.