Assessing specific causation of mesothelioma following exposure to chrysotile asbestoscontaining brake dust

Background: The question of whether chrysotile asbestos-containing brake dust can plausibly serve as a cause of mesothelioma in an exposed individual has become a matter of heated debate in the medical literature despite multiple international, federal, and state governmental agencies acknowledging a causal association. Objectives: We describe and provide an analysis of various industry and academic perspectives contributing to the debate. Methods: A framework is presented for evaluating the general and specific causal relationship between brake dust exposure and mesothelioma utilizing the principles of forensic epidemiology, and by applying the Bradford-Hill criteria. Results and conclusions: We conclude that there is a "net" of evidence favoring a causal relationship between brake dust-associated chrysotile exposure and mesothelioma. The industry-sponsored position that there is insufficient evidence to support a contiguous "chain" of causation is specious from both a methodologic and evidentiary perspective. Finally, we suggest a semiquantitative approach for the evaluation of individual causation in putative cases of mesothelioma with a history of significant brake dust exposure.