Environmental sample correlation with clinical and historical data in a friction product exposure

Asbestos has been widely used in the past as a component in friction products. A unique setting of dust exposure to such products occurs when individuals are involved with refabrication of the worn components. It is of interest whether asbestos fibers are released from friction materials in the use phase and the postlife phase or if the mineral fibers are converted to a nonasbestos form. In the present study, an individual whose primary work activity had centered on clutch refabrication was evaluated for possible dust-related diseases. Tissue analysis revealed the presence of large numbers of asbestos fibers as well as ferruginous bodies. These particulates were characterized as to composition as well as dimensions. Clutches of the type typically used by this individual were obtained and material was rinsed from their surface for comparative purposes. Materials that were freed from the surface and reviewed by analytical transmission electron microscopy were clearly identifiable as chrysotile asbestos. The composition of the clutch material was compared with the components found in the patient's lung tissue. The conclusion from this comparison was that individuals exposed to friction materials under similar circumstances should use appropriate caution. Appreciable exposure to asbestos can occur and this exposure can be sufficiently high to result in disease.