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

Background: In Atkinson et al. 2004 rinsates of unused brake components were analyzed by transmission electron microscopy (TEM) for the presence of asbestos fibers.

Results: We do not believe that the findings of Atkinson et al. are informative and could have been predicted based on the study design and the fact that one would expect to find measurable TEM asbestos fibers on an unused brake component. We also find that the paper did not provide a full or even partial discussion of the published literature with respect to industrial hygiene or epidemiology data.

Conclusion: The findings of Atkinson et al. do not, in our view, "further raise concerns" about historical asbestos exposures experienced by automotive mechanics because of the vast amount of published literature to the contrary.