Document VE29m7D3ojOxyM88o9wy75Qq

FILE NAME: Ford (FD) DATE: 1976 DOC#: FD026 DOCUMENT DESCRIPTION: Journal Article - Asbestos Exposure during Brake Lining Maintenance and Repair E N V I R O N M E N T A L R E S E A R C H 12, 110 128 ( 1976) Reprinted from Environmental Research 12, 110-128 (1976) Copyright 1976 Academic Press, Inc. Printed in U.S.A. Asbestos Exposure during Brake Lining Maintenance and Repair1 A r t h u r N. R o h l , A r t h u r M. L a n c e r , MaryS. W o l f f , an d Irving W eisman Environmental Sciences Laboratory, Mount Sinai School o f Medicine o f the City University o f New York, New York, New York 10029 Received December 10, 1975 Data obtained on asbestos exposure of garage mechanics during brake lining maintenance and repair work show that fiber concentrations frequently in excess of regulated limits arc common. The presence of chrysotile. ranging from 2 to 15%, in brake drum dusts, was demonstrated by X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and electron microprobe analyses. Unaltered chrysotile was found, both in fiber and fibril form, in air and brake drum dust samples. The chrysotile asbestos content of personal air samples, taken during automobile brake repair work, was measured both y optical and electron microscopic techniques. While a positive correlation exists between the types of measurements, the present technique of optically counting asbestos fibers may considerably underestimate the levels of total asbestos exposure. INTRODUCTION During the past decade, significant disease risk has been found associated with the inhalation of asbestos fibers in a number of occupational and environmental circumstances other than in asbestos mining, milling and manufacturing, where serious hazard was already known (Wagner el al., 1960; Newhouse and Thompson, 1965; Selikoff el al., 1964, 1965; Harries, 1968). Such exposures were found in the construction industry and tn shipbuilding, as well as in other industrial settings where asbestos products were used. More recently, asbestos exposure has been suggested to occur during automotive brake lining repair and installation work, and measurable concentrations of asbestos fiber were observed in the work environment of workmen involved in these opera tions (Hickish and Knight, 1970; Hatch, 1970; Boillat and Lob, 1973). With limited data available, however, uncertainty remained regarding the type and extent of asbestos exposure during this work. Some investigators have questioned whether free asbestos fibers survive the high temperatures produced during braking action (Lynch, 1968; Hickish and Knight, 1970; Hatch, 1970) contending that asbestos decomposes as a result of the high point contact temperatures produced at the interface of the brake drum or disc and brake lining. We have sought to obtain information concerning asbestos exposure of work men engaged in brake lining maintenance and brake shoe installation, by analysis of residual dusts recovered from brake linings and by direct measurement of the 1This research was supported by Center Grant ES 00928 of the National Institute of Environmental Health Sciences of the U.S. Department of Health, Education and Welfare. Assistance was also provided in part by the Health Research Council of the City of New York HRC U 2329 and by the Ford Motor Company. Copyright () 1976 by Academic Press. Inc. AH rights o f reproduction In any form reserved. 110