Evaluation of Asbestos Exposure during Brake Repair and Replacement

Abstract

Occupational exposure to asbestos fiber of brake repair job (auto mechanics) has seldom been evaluated in Iran. Accordingly, we evaluated asbestos fiber concentrations in the breathing zone of auto mechanics between July 2008 and December 2008. The asbestos fiber concentrations of 60 personal air samples collected from 30 cars and trucks brake replacement and they were analyzed by phase-contrast optical microscopy (PCM) and scanning electron microscopy (SEM) by energy-dispersive X-ray analysis. The geometric means of the personal monitoring fiber concentrations were 0.92 PCM f/ml and 0.46 PCM f/ml respectively in car and passenger heavy truck auto shops. There was a significant differences in the asbestos fiber concentrations between the car and truck auto shops (p=0.006). Based on these findings, auto mechanics who worked with asbestos containing brake may have been exposed to asbestos concentrations approximately 7 times higher than the current occupational safety and health agency (OSHA) permissible exposure limit (PEL) of 0.1 f/ml. Fiber morphology and energy dispersive X-ray analysis by SEM revealed that amphibole fibers such as tremolite and actinolite existed in the brakes dust and that the vast majority (>30%) of the airborne chrysotile fibers were greater than 1 μm in diameter. It can be concluded that the imported chrysotile asbestos contains trace amounts of tremolite and actinolite fibers and they are responsible for the high airborne asbestos levels and occupational exposure to amphibole asbestos in auto mechanics job in Iran. Thus, it is to be expected that the auto mechanics will suffer negative health effects due to exposure to the serpentine and amphibole asbestos fibers.

The toxicology of chrysotile-containing brake debris: implications for mesothelioma

“…To the most part, chrysotile was the only asbestos fiber noted in the analysis of air samples taken during brake repair and servicing. However, a study addressing potential "asbestos" exposure in mechanics in Iran replacing chrysotilecontaining brake pads in 2008 found that while the majority of fibers detected were chrysotile ($70%), tremolite and actinolite fibers were also detected (Kakooei et al 2011). The reason for the detection of amphiboles in this study yet not others may be due to several factors.…”

“…However, these methods are limited to the detection of fibers greater than 0.25 lm in diameter and so thinner fibers may not be counted but are still biologically relevant. Kakooei et al (2011) however employed PCM and SEM based on methods by the Asbestos International Association (AIA 1984) which allowed counting of much thinner fibers also.…”

“…Although plausible given the common contamination of chrysotile with amphiboles, studies characterizing the released particles have not reported the presence of amphiboles. Furthermore, the majority of reported sampling studies of the occupational environment of mechanics has not described the presence of amphibole although there are exceptions (Kakooei et al 2011). However, as amphiboles comprise a tiny contaminating fraction of some chrysotile deposits and limited release of free fibers from brake pads, the lack of observation is not unlikely.…”

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

“…The worker in question had self-reported occupational asbestos exposure working as a vehicle mechanic for 6.5 years. Numerous studies have shown that vehicle mechanics are exposed to asbestos-containing materials, which can result in adverse health effects, including lung cancer and mesothelioma (Castleman et al, 1975;Egilman & Billings, 2005;Egilman & Longo, 2012;Finkelstein, 2008;Freeman & Kohles, 2012;Hansen, 1989;Huncharek, 1990Huncharek, , 1992Imbernon et al, 2005;Kakooei et al, 2011;Lemen, 2004;Michaels & Monforton, 2007;Roggli et al, 2002;Welch, 2007). For example, in the analysis of 1445 cases of mesothelioma studied by Roggli et al (2002), the automotive sector ranked eighth in terms of the number of mesothelioma cases among 12 industrial sectors evaluated.…”

Asbestos Exposure among Construction Workers During Demolition of Old Houses in Tehran, Iran

“…In 2010, the municipal of Tehran estimates that 16300 older housing units will be demolished in urban areas. Asbestos is a fibrous silicate minerals, which are easily separated into thin, long, and flexible fibers when crushed or processed 1 , 2 ) . These fibrous materials subdivided into two groups, serpentine group (chrysotile),which is used as the most commonly form of asbestos, and amphibole group (tremolite asbestos, amosite asbestos, actinolite asbestos, anthophllite asbestos, and crocidolite asbestos 3 ) .…”