Evaluation of the size and type of free particulates collected from unused asbestos-containing brake components as related to potential for respirability

BACKGROUND: Chrysotile asbestos has found multiple applications in the production of friction products. At one point it comprised 40-50% of the composition of brake linings thus generating the potential for the development of asbestos related diseases in millions of workers involved in vehicle repairs. While some attention has been given to the health status of workers involved in the handling of worn components, little has been given to the potential for exposure during the handling and fitting of new (unused) components as replacement parts. METHODS: Unused brake linings or brake shoes with attached linings from four different sources were gently rinsed with prefiltered water that was then collected on filters for analysis by Analytical Transmission Electron Microscope. RESULTS: Large numbers of chrysotile asbestos containing structures, the majority of respirable size, were present in each sample. CONCLUSIONS: We conclude that any manipulation of new asbestos containing brake components would be expected to yield free dust containing chrysotile asbestos of respirable size. That the vast majority of these fibers and particulates would not be counted as regulated fibers rendering assessment of potential exposures in the work place, based on data of Permissible Exposure Limits or Regulated Fibers, questionable.