An evaluation of short-term exposures of brake mechanics to asbestos during automotive and truck brake cleaning and machining activities

Malignant pleural mesothelioma in US automotive mechanics: Reported vs expected number of cases from 1975 to 2007

“…Although asbestos-containing friction products were largely phased out of automobile replacement parts manufactured in the US by the early 1990s, recent reports indicate that asbestos may still be used to manufacture brakes and clutches in other countries (EPA, 1989;Kakooei and Marioryad, 2010). Several studies have reported airborne asbestos concentrations during automotive repair; some have evaluated short-term, specific tasks, such as opening boxes of asbestos-containing brakes and clutches (Jiang et al, 2008;Madl et al, 2008) or brake grinding (Richter et al, 2009), while others have measured time-weighted average (TWA) asbestos concentrations throughout an entire brake job (Blake et al, 2003;Johnson et al, 1979;Roberts, 1980a,b;Roberts and Zumwalde, 1982;Weir et al, 2001). Using job tenure data for US automotive mechanics, Finley et al (2007) estimated that median cumulative lifetime asbestos exposures ranged from 0.16 to 0.41 fiber/cc-year for facilities with no dust-control procedures (1970s), and from 0.010 to 0.012 fiber/cc-year for those employing engineering controls in the later years (1980s).…”

Review of refractory ceramic fiber (RCF) toxicity, epidemiology and occupational exposure

“…Epidemiology studies of occupationally exposed cohorts are less easy to interpret, with some studies or analyzes concluding that automobile mechanics have an elevated risk. Nonetheless, other studies and meta-analyzes indicate that mesothelioma risks are not significantly elevated (Aguilar-Madrid et al, 2010;Butnor et al, 2003;Dotson, 2006;Finley et al, 2012;Garabrant et al, 2016;Goodman et al, 2004;Hessel et al, 2004;Laden et al, 2004;Paustenbach & White, 2012;Peto et al, 2009;Rake et al, 2009;Richter et al, 2009;Teschke et al, 1997;Wong 2001Wong , 2006. This certainly does not mean that the incremental risks are zero.…”

Re: Comments on Egilman's response to Hessel regarding the health hazards of brake dust and his reflections on corporate behavior

“…In the view of these same scientists, the low potency of chrysotile, the lack of biologic activity of brake wear debris and raw brake dust (like from a grinder), the low dose (concentration x time), and the epidemiology data all strongly indicate that the risk of mechanics developing mesothelioma due to their work as mechanics was de minimis. 3,[48][49][50][51][52][53][54][55][56][57] It is recognized that some scientists and physicians believe the evidence is that brake dust has produced mesothelioma in some mechanics, as evidenced in numerous amicus briefs on this matter. 58 Lynch et al 56 more than 50 years ago, Jacko et al, 57 and others showed that brakewear debris should likely not be an asbestos hazard due to fiber size, clumping and conversion to forsterite.…”

“…Papers by Paustenbach et al, 50 Richter et al, 53 It is logical that 99.5% of asbestos in brakes are broken down during braking. 55,56 Dr. Egilman fails to tell readers about the lack of relevance of his citations with respect to the hazard to mechanics in the United States.…”