Asbestos brake emissions

Williams, Ronald L.; Muhlbaier, J. L.

doi:10.1016/0013-9351(82)90008-1

Cited by 53 publications

(32 citation statements)

References 9 publications

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“…In a number of industrial hygiene reports detailing asbestos exposures among automotive mechanics, the concentration of airborne asbestos has been below the Occupational Safety and Health Administration's permissible exposure limit (PEL) of 0.1 fiber/cm 3 (National Institute for Occupational Safety and Health, 1980a,b;Cheng and O'Kelly, 1986;Rodelsperger et al, 1986;Kauppinen and Korhonen, 1987). The low level of airborne chrysotile liberated during brake repair is consistent with the results of analyses of brake dust samples (Williams and Muhlbaier, 1982). Chrysotile fibers in unworn brake linings are entirely in a bonded or encapsulated state.…”

Section: Discussionsupporting

confidence: 65%

“…Of the small number of residual intact chrysotile fibers, most remain embedded in the plastic binding material. Less than 0.1-1% of the fibers in brake dust are free chrysotile, the majority of which are short fibers, <1 µm in length (Lynch, 1968;Hatch, 1970;Davis and Coniam, 1973;Williams and Muhlbaier, 1982;Wong, 2001). Of note, a considerably higher concentration (2-15%) of free chrysotile has been detected in used brake linings .…”

Section: Discussionmentioning

confidence: 99%

“…During braking, temperatures exceeding 700-800°C are reached. Much of the chrysotile is broken down into forsterite, a non-asbestos anhydrous magnesium silicate (Williams and Muhlbaier, 1982;Wong, 2001). Of the small number of residual intact chrysotile fibers, most remain embedded in the plastic binding material.…”

Section: Discussionmentioning

confidence: 99%

“…Analyses of brake dust have shown that it contains <1% asbestos, most of which is short chrysotile fibers <1 µm in length, with much of the asbestos having been converted to forsterite due to the heat generated during the braking process (Williams and Muhlbaier, 1982). Conclusions on the relationship between brake dust exposure and MM have been based predominantly on epidemiological studies, which have shown no increased risk of MM resulting from exposure to automotive friction products (McDonald and McDonald, 1980;Teta et al, 1983;Spirtas et al, 1985Spirtas et al, , 1994Woitowitz and Rodelsperger, 1994;Teschke et al, 1997;Agudo et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Exposure to Brake Dust and Malignant Mesothelioma: A Study of 10 Cases with Mineral Fiber Analyses

2003

The Annals of Occupational Hygiene

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Objectives: A large number of workers in the USA are exposed to chrysotile asbestos through brake repair, yet only a few cases of malignant mesothelioma (MM) have been described in this population. Epidemiologic and industrial hygiene studies have failed to demonstrate an increased risk of MM in brake workers. We present our experience of MM in individuals whose only known asbestos exposure was to brake dust and correlate these findings with lung asbestos fiber burdens.Methods: Consultation files of one of the authors were reviewed for cases of MM in which brake dust was the only known asbestos exposure. Lung fiber analyses were performed using scanning electron microscopy (SEM) in all cases for which formalin-fixed or paraffinembedded lung tissue was available.Results: Ten cases of MM in brake dust-exposed individuals were males aged 51-73 yr. Nine cases arose in the pleura and one in the peritoneum. Although the median lung asbestos body count (19 AB/g) is at our upper limit of normal (range 0-20 AB/g), half of the cases had levels within our normal range. In every case with elevated asbestos fiber levels by SEM, excess commercial amphibole fibers were also detected. Elevated levels of chrysotile and non-commercial amphibole fibers were detected only in cases that also had increased commercial amphibole fibers.Conclusions: Brake dust contains exceedingly low levels of respirable chrysotile, much of which consists of short fibers subject to rapid pulmonary clearance. Elevated lung levels of commercial amphiboles in some brake workers suggest that unrecognized exposure to these fibers plays a critical role in the development of MM.

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Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Exposure to Brake Dust and Malignant Mesothelioma: A Study of 10 Cases with Mineral Fiber Analyses

2003

The Annals of Occupational Hygiene

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“…53 If these fibers were of importance in causation of mesothelioma, then brake mechanics who are exposed to brake dust (in which the vast majority of residual fibers are ,1 lm in length) should have very high rates of mesothelioma. 54 However, numerous epidemiological investigations that have examined this question have found no evidence of an increased risk of mesothelioma among auto mechanics. 55 AUST REVIEW Aust and colleagues 46 reported a review of the literature regarding mechanisms of toxicity associated with elongated mineral particles.…”

Section: Dodson and Lemen Reviews Dodson And Colleaguesmentioning

confidence: 99%

The So-called Short-Fiber Controversy: Literature Review and Critical Analysis

Roggli

2015

Archives of Pathology &Amp; Laboratory Medicine

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Context Numerous articles in the scientific literature indicate that pathogenic fibers with respect to asbestos-related diseases are those that exceed 5 μm in length. Nonetheless, some authors have expressed concerns regarding pathogenicity of shorter fibers. Objective To review the scientific evidence regarding pathogenicity (or lack thereof) of fibers less than or equal to 5 μm in length, with particular attention to publications indicating that such fibers might be hazardous. Data Sources The scientific literature was reviewed for experimental animal studies and human studies that address the role of fiber size in causation of disease. Sources included original studies, as well as review articles related to the topic. Conclusions Experimental animal studies involving inhalation of fibers have demonstrated that fibers greater than 5 μm in length are associated with both pulmonary fibrosis (ie, asbestosis) and malignancies (carcinoma of the lung and mesothelioma). There is no convincing evidence for a pathogenic effect for fibers that are 5 μm or less in length. Fiber analyses of human lung tissue samples provide further support for pathogenicity of long fibers, particularly the more biopersistent amphibole fibers. Similar observations have been reported for nonasbestos mineral fibers. Concerns expressed by some authors (eg, the greater abundance of short fibers) do not alter these conclusions. Similarly, in vitro studies demonstrating biological activity of short fibers do not override inhalational studies of whole animals or the epidemiological findings in humans.

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