COMPARISON OF PERSONAL EXPOSURES TO ASBESTOS FIBERS BETWEEN BRAKE AND TRANSMISSION MECHANICS DURING THE MANIPULATION PROCESSES OF ASBESTOS CONTAINING PRODUCTS

摘要

Background: In Colombia, asbestos containing brake and transmission products are still used in passenger and heavy-duty vehicles. Asbestos containing brake linings and clutch discs are sold detached from their supports, and because of this they require manipulation before installation. The manipulation processes for both types of products include drilling, countersinking, riveting, and grinding, activities that can release asbestos fibers. Aims: Compare short-term personal exposures of brake mechanics and transmission mechanics that result from the manipulation of asbestos containing brake linings and clutch discs. Methods: Five shops dedicated to the preparation of asbestos containing brake linings or clutch discs were sampled in this study. Short Term Personal Samples (i.e., 30 min) were collected in workers following NIOSH methods 7400 and 7402. Manipulation processes performed by each worker were recorded in activity diaries. Personal samples were collected in 7 brake mechanics (i.e., 42 short term samples) and 3 transmission mechanics (i.e., 36 short term samples). Asbestos counting was conducted by AIHA accredited US laboratories. A t-test was applied to determine if there was a significant difference in means between 30 minutes PCM fiber concentrations of the two occupational groups. Results: The mean PCM 30 min fiber concentration for brake mechanics was 0.129 f/cc and for transmission mechanics was 0.105 f/cc. The mean difference between the two occupational groups was not statistically significant (p=0.3107). Conclusions: Although the asbestos containing products (i.e., brake linings and clutch discs) differed between the two occupational groups, the manipulation activities performed on these products were similar. This could explain the similarity between groups in terms of short-term fiber exposures. Thus, the potential health risks for both types of workers could be similar. All the samples collected did not exceed the asbestos OSHA STEL.