In-Depth Survey Report: Evaluation of Brake Drum Service Controls at Cincinnati Bell Maintenance Facility, Fairfax, Ohio

摘要

The effectiveness of vacuum units (Nilfisk Asbestos-Clene System) equipped with high efficiency particulate air filters in limiting exposure to asbestos (1332214) during the servicing of automotive brakes was evaluated. Brake servicing of seven vehicles at the Cincinnati Bell Fairfax Garage was studied. Phase contrast microscope (PCM) analyses of personal air samples, collected for the duration of a single brake job or for 2 hours, whichever was longer, yielded counts ranging from 0.004 fiber per cubic centimeter (f/cc) (detection limit) to 0.016f/cc using an aspect ratio of 5:1. Effective control was evidenced by the low exposures for the brake mechanics; 79 percent of the air samples, including personal, axle, fender, background, and ambient samples were below detectable limits. Transmission electron microscopy also showed very low asbestos concentrations. The authors caution that workers should not use a dry cloth to clean hands after finishing a brake job. Instructions are offered for safe removal and replacement of the various filters in vacuum units.