Asbestos in brakes: Exposure and risk of disease (original) (raw)
Related papers
Personal Exposures to Asbestos Fibers During Brake Maintenance of Passenger Vehicles
Annals of Occupational Hygiene, 2012
Introduction: Brake linings and brake pads are among the asbestos-containing products that are readily available in Colombia. When sold separated from their support, brake linings require extensive manipulation involving several steps that include drilling, countersinking, riveting, bonding, cutting, beveling, and grinding. Without this manipulation, brake linings cannot be installed in a vehicle. The manipulation process may release asbestos fibers, which may expose brake mechanics to the fibers. Methods: Three brake repair shops located in Bogotá (Colombia) were sampled for 3 or 4 consecutive days using US National Institute for Occupational Safety and Health (NIOSH) methods 7400 and 7402. Standard procedures for quality control were followed during the sampling process, and asbestos samples were analyzed by an American Industrial Hygiene Association accredited laboratory. Personal samples were collected to assess full-shift and short-term exposures. Area samples were also collected close to the brake-lining manipulation equipment and within office facilities. Activities were documented during the sampling process. Results: Using Phase Contrast Microscopy Equivalent counts to estimate air asbestos concentrations, all personal samples [i.e. 8-h time-weighted averages (TWAs) and 30-min personal samples] were in compliance with the US Occupational Safety and Health Administration standards. Personal asbestos concentrations based on transmission electron microscopy counts were extremely high, ranging from 0.006 to 3.493 f cm −3 for 8-h TWA and from 0.015 to 8.835 f cm −3 for 30-min samples. All asbestos fibers detected were chrysotile. Cleaning facilities and grinding linings resulted in the highest asbestos exposures based on transmission electron microscopy counts. There were also some samples that did not comply with the NIOSH's recommended exposure limits. Conclusion: The results indicate that the brake mechanics sampled are exposed to extremely high asbestos concentrations (i.e. based on transmission electron microscopy counts), suggesting that this occupational group could be at excess risk of asbestos-related diseases.
Personal exposure to asbestos and respiratory health of heavy vehicle brake mechanics
Journal of Exposure Science and Environmental Epidemiology, 2014
Asbestos brake linings and blocks are currently used in heavy vehicle brake repair shops (BRSs) in Bogotá, Colombia. Some brake products are sold detached from their supports and without holes, requiring manipulation before installation. The aim of this study was to assess asbestos exposures and conduct a preliminary evaluation of respiratory health in workers of heavy vehicles in BRSs. To estimate asbestos exposures, personal and area samples were collected in two heavy vehicle BRSs. Each shop was sampled during six consecutive days for the entire work shift. Personal samples were collected on 10 workers including riveters, brake mechanics, and administrative staff. Among workers sampled, riveters had the highest phase contrast microscopy equivalent (PCME) asbestos concentrations, with 8-h time-weighted average (TWA) personal exposures ranging between 0.003 and 0.157 f/cm 3. Respiratory health evaluations were performed on the 10 workers sampled. Three workers (30%) had circumscribed pleural thickening (pleural plaques), with calcifications in two of them. This finding is strongly suggestive of asbestos exposure. The results of this study provide preliminary evidence that workers in heavy vehicle BRSs could be at excessive risk of developing asbestos-related diseases.
Asbestos base and asbestos free brake lining materials : comparative study
International Journal of Scientific World, 2017
Frictional brake lining materials are broadly made of asbestos as their constituent. But asbestos is dangerous for handling due to health hazardous. Asbestos has ample physical, mechanical and tribological properties. The material replacing it should have all these properties with no undermine. In this paper a study on asbestos base and asbestos free brake lining material is presented. Purpose behind this is combine the demerits of asbestos free and asbestos base materials with comparable properties. Some organic waste from farm like banana peel, palm karnel shell, were also tested for the replacement of asbestos and they found worth through comparison with each others.
Toxicology and Applied Pharmacology, 2014
Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (N20 μm) cleared quickly with T 1/2 estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T 1/2 N 1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung following short term inhalation.
Respiratory impairment due to asbestos exposure in brake-lining workers
Environmental Research, 2003
There is extensive evidence that exposure to asbestos causes pulmonary parenchymal fibrosis, pleural disease, and malignant neoplasm in asbestos-exposed workers. However, few data concerning brake-lining workers are available in the literature. In this study, we aimed to assess the long-term effects of chrysotile asbestos exposure on lung function and the risk of asbestos-related diseases in brake-lining workers. Seventy-four asbestos-exposed workers who processed brake-lining products and 12 unexposed office workers were offered pulmonary function tests (spirometry and transfer factor) in 1992 and 1999. In 1999, the mean duration of asbestos exposure was 10.0074.07 and 11.0274.81 years (7-31 years) in nonsmoking and smoking asbestos workers, respectively. Transfer factor (T L ; CO) and transfer coefficient (K CO) decline were significant in the 7-year follow-up in both smoking and nonsmoking asbestos workers. However, lung function indices of the control group, whom were all current smokers; were also found to be decreased, including FEF 75 , T L ; CO and K CO : We found minimal reticular changes in 10 asbestos workers who were all current smokers, they underwent high-resolution computed tomography scans of the chest and we found that they had peribronchial thickening resulting from smoking. As a conclusion, even in the absence of radiographic asbestosis, T L ; CO and K CO may decrease after a mean 10-year duration of exposure to asbestos in brake-lining workers and this is more noticeable with cigarette burden.
Estimation of personal exposure to asbestos of brake repair workers
Journal of Exposure Science and Environmental Epidemiology, 2016
Exposure assessments are key tools to conduct epidemiological studies. Since 2010, 28 riveters from 18 brake repair shops with different characteristics and workloads were sampled for asbestos exposure in Bogotá, Colombia. Short-term personal samples collected during manipulation activities of brake products, and personal samples collected during non-manipulation activities were used to calculate 103 8-h TWA PCM-equivalent personal asbestos concentrations. The aims of this study are to identify exposure determinant variables associated with the 8-h TWA personal asbestos concentrations among brake mechanics, and propose different models to estimate potential asbestos exposure of brake mechanics in an 8-h work-shift. Longitudinal-based multivariate linear regression models were used to determine the association between personal asbestos concentrations in a work-shift with different variables related to work tasks and workload of the mechanics, and some characteristics of the shops. Monte Carlo simulations were used to estimate the 8-h TWA PCM-Eq personal asbestos concentration in work-shifts that had manipulations of brake products or cleaning activities of the manipulation area, using the results of the sampling campaigns. The simulations proposed could be applied for both current and retrospective studies to determine personal asbestos exposures of brake mechanics, without the need of sampling campaigns or historical data of air asbestos concentrations.
IRJET- Safer Alternatives to Asbestos in Asbestos-Free Brake Pad Manufacturing: A Review
IRJET, 2020
At present there are different materials that are well suited and are in use for making the brake pads, the most common being asbestos but there are serious carcinogenic effects associated with asbestos which led to its gradual phase out. With the phasing out of asbestos as automotive friction lining material a need arouse of finding its safer alternatives with the same properties which can be deployed in its place fulfilling the condition of a non-carcinogenic material. This led to onset of research in this field i.e. to find a material having the required properties and that performs the same task. This research gave birth to different composites having different composition and giving the required results. In this review paper different safer alternatives that are environment friendly with their approximate composition are studied which includes agricultural or natural wastes i.e. materials such as banana peels, palm kernel shells, groundnut shell, maize husk, jute, coconut shell etc. Different constituents of composite which includes filler materials, binders like epoxy resin, phenolic resin are also studied and composites are procured by varying the composition of these constituents.
Asbestos Waste Audit and Recycling in an Automobile Brake Manufacturing Facility
Journal of Environmental Systems, 2001
A waste audit study, using a modified protocol based on the U.S. EPA Waste Audit Guidelines, was carried out in a brake manufacturing facility, by observing and analyzing each of the process steps-mixing, preforming, molding, oven curing, cutting, grinding, drilling, wear evaluation, chamfering, and branding and packaging. Additionally, studies on waste minimization through recycling of the waste brake lining dust into the virgin mix and the effect of this recycling on subsequent product performance quality were also carried out. The audit showed that there was generation of waste at just about every step of the process, as evidenced by weight loss calculations on the original mix entering the process. For example, in the cutting step this loss was about 30 percent, in grinding it ranged from 10.64 percent to 13.03 percent, in drilling from 2.17 percent to 6.8 percent, and in chamfering from 0.49 percent to 1.07 percent; in the case of cutting this included both cutting residues and fines while in the rest of the cases these were only fines. Next, in evaluating the recycling of the fines, recycling 5 percent to 10 percent of the lining waste dust into the virgin mix retained the specific gravity of the brake lining samples well within the specification requirement range of 2.12 to 2.32. Additionally, inertia dynamometer tests were carried out on the linings produced from the 5 percent and 10 percent recycling mix, with *The project was funded by a PJP grant from the University of Malaya. ✝ Fullbright visiting professor.