Document 3NQqNoK0pLJg1qjzywpEK51RO

The Hazards of Asbestos for Brake Mechanics i ! i i BARRY CASTLEMAN, LUCILLE A. CAMAROTA. ALBERT J. FRITSCH, SUSAN MAZZOCCHI, and ROBERT G. CRAWLEY ASBESTOS is the generic name of a group of hydrated disk pads, and clutch facings for the past 50 years.. magnesium silicate mineral fibers. There are two Jacko and DuCharmeYU) estimated that the United groups of these minerals--serpentine (chrysotile) and States annually uses 103 million pounds of asbestos for amphibole (amositc, crocidolite, anthophyllite, brake friction materials and 4.5 million pounds in trem'oliie, and actinolite).. Ninety-five percent of the automotive clutch friction materials. world's asbestos production is chrysotile. In 1968 Lynch reported that because of the heat of Reports of epidemiologic and pathological studies friction caused by braking, almost all of the asbestos in (1--4) reveal that occupational exposure to commercial brake linings is transformed to a nonfibrous mineral, ' asbestos minerals enhances the likelihood of a number and a small fraction of asbestos escapes as free fiber of diseases--asbestosis and cancers of the lung, pleura, (12). lacko and co-workers determined that vehicles in peritoneum, larynx, and gastrointestinal tract. The this country emit 158,000 pounds of asbestos per year, time from onset of exposure to the time of clinically ap- of which 11.2 percent is retailed in the brake and dis- parent disease is usually more than 20 years. Cancer posed of during service (13). from asbestos is not limited to workers who handle the Brake mechanics have low and intermittent exposure material. There arc also reports of pleural and to asbestos. This exposure has been reported to be 0.79 peritoneal mesothelioma (tumors rarely seen in the fiber per ml time-weighted average (fibers longer than 5 general population) in persons with family, or microns), with peaks up to 7 fibers per mi when brake neighborhood, or indirect occupational exposure to parts are being cleaned (14). The standard method for asbestos (4--7). removing dust from brake parts is to blow it out with a Mesothelioma was the cause of death of a man who___________ _________________________ had regularly sanded vinyl asbestos floor tile (8). Under CJMr. CastUman, an environmental engineer, was with the simulated conditions of this mans work, a maximum Center for Science in the Public Interest when this paper was asbestos dust concentration of 1.3 fibers per ml (fibers prepared; he is now with the Maryland Ihiblic Interest Research longer than 5 microns) was found in air samples passed Group. Dr. Frilsch ts director of the Center fur Science in the through membrane niters worn by a person sanding /Mfo Interest. Ms. Camarota is an occupational health nurse, vinyl asbestos (S). The type of asbestos now used in District of Columbia Department of Human Resources. Ms. domestic floor tile is chrysotile--the same as that used Aln^guuht was a research associate. Environmental Cancer in brake friction materials, according to the Asbestos Research Project, Environmental Sciences Laboratory, Mount Information Association. A case of mesothelioma in a glnal School of Medicine. New Tork City., Mr. Crawley is a brake mechanic has been reported (9). sanitarian, llaltirnore County Department of Health. Commercial friction materials used in the United Tearsheet requests to Parry CastUman,'Maryland Public States for braking passenger cars and trucks contain an- /merest Research Croup, 3110 New Main Dining. Hall, average composition of 50 percent chrysotile by weight University of Maryland, College Park, MJ. 20742. (10). Asbestos has been used for brake drum linings, _-------- ------------- -------------------------------- ----------- ------- - 254 Public HoAtth fiopons ! J } | j *. j \ .J j > I HWBUI0011630 omprrssed air hose. In 1970 several reports (f t--IS) escribed the levels of exposure of hr.ike mechanics to sbestos, alternative hiction materials, and .specific hanges in brake repair practices which would reduce he levels of exposure. Baltimore and Washington Studies n December 1972, the Baltimore County Department >f Health mailed a I-page mimeographed circular to vbout 130 establishments which provide brake repair tervicc. These businesses included new car and truck dealerships, certified motor vehicle inspection stations, and other concerns advertising brake repair as a specialty. Some of the establishments initially con tacted had cither gone out of business or replied that they do not do brake repairs. The circular warned that inhalation of the dust from brake cleaning could cause serious diseases, inducting cancer, and . advised vacuuming brakes of accumulated dust. Additional measures suggested were improved ventilation and the use of face masks (19). Two student volunteers went to 100 of the places on the mailing list 4 months later to ask shop managers what methods they were using in brake repair. A similar study was started in Washington, D.C., in August 1973. This work was conducted by the Center for Science in the Public Interest and the District of Columbia Department of Human Resources. Of 1S6 brake service establishments initially contacted,. 120 were followed up. Several new methods were tried in order to improve the effectiveness of the warning. The warning leaflet was more eye-catching and readable than, the paragraph-form sheet used in Baltimore; the leaflets were handed out by an occupational health nurse to the mechanics themselves--none were mailed; and followup to ascertain the degree of effectiveness was conducted by the same nurse who interviewed the repair shop managers. The Washington study was also featured in a local television program at the time the leaflets were first handed out. FrmOrtfertfcCv* * -v 1*4at <NI 4 I -#Tr**T wa t* ftfacM **.<4 W 4*'* iAaattt avH** r* kr* * tart WakyiaM*M. *44r*>***'< a--'** te* JitiUjU-njclto tbj l Donlj far to^ ta ^ata pw< *" avtaUca 4|*>f t>i | ie*c. | 60*TT 4**a kriVa I 4--. h*< |M|M k* *4> | bO*rr K4 >. k, # [ ***** V'att< * 00*M*a>-.MAa *1*4 %a Jim < < *. | OQ vav*4 A* <**>* UV 4 ta>*ta. WJat VTii HI I fa*k* !.--* MI*< IW aiatidi t-h4,4 *Ji larwka^. P'4 rt4 #J !* *441 *tf aaatt atJ j *1 t.~,r44**> *44 i anal tMllkn **a I I A.*4f 4 **.*** |1 4 fk 4tk d 4 t.4* niv*j 4aN a. 4*4 . 4 A* iJaa>>k j 4 1* *** ll <** V !>.*< a* * V4!*M0****4*. t JJOUV-aa,Nt ' Well I OO 4*4 % 4^.-41 *| fia 4*4 k*at la*)' ltl W r k4 t.<iv*>w ti C***a* tw >4 4 1 M> t*** 4 4 | Atk**-*l*t*4 4. Mat lit 4 '.0 |M>> II **W l' 4wava V4**< 44, j BRAKE REPAIR WORK CAH BE iitqar4*u& TO YOUR HEALTH To assure that students trained in brake repair by public vocational schools would lear,n proper methods, health officials tnet with appropriate school officials iji both locations. At the time they were contacted, school officials in Baltimore and Washington reported that the schools were teaching the "blow out" method of brake dust removal to the trainees. The standard method of cleaning brakes is "blowing out" with a compressed air hose. In Baltimore, 65 per cent (65 per 100) of the brake repair establishments contacted were using this method at the time they received the warning circulars. In Washington, the figure was 91 percent (110 of 120). Most of the managers and workers interviewed had never heard about the hazardous potential of brake dust. Predict ably, the responses ranged from annoyance to apprecia tion. Of the 65 places in Baltimore initially blowing out brakes, 11 were using cither vacuum or wet brushing methods at the time of followup. Four others were still blowing out brakes, but had improved ventilation or provided dust masks, or both, to reduce workers' ex posures. In Washington, only two establishments had changed to wet brushing, but none were vacuuming brakes. Four others provided face masks. Interestingly, two others decided to change brake shoes in all brake repairs, thereby simplifying the problem of dust removal and reducing the mechanics' exposures. The degree of improvement, indexed by the percent-, age of establishments converting from blowing out brakes to safer techniques after a single warning, was 23 percent in Baltimore County and 7 percent in Washington. This disparity probably arises more from differences in the methods of the studies than, from differences in the study groups. It may be critically important to approach manage ment at the outset in order to enlist the cooperation needed to implement any changes in practice. A mechanic who is approached directly with a warning may simply disregard it. The mechanic might reason that if the dust were really dangerous, there would be a law requiring the use of preferred methods in brake repair. And the employer, if not asked to participate from the beginning, may well conclude that lie need not be concerned with the matter. T he failure to involve management may be the main reason why the Washington study produced less gratifying results than the Baltimore study. Brake warning programs consisting merely of mailed warning notices require little manpower, compared to other health programs. Also, the effort to implement safe techniques in public vocational schools is time well spent. Conclusion Over a 7-year period, ending in 1976 ( JO,21), the U.S. standard for time-averaged exposure to asbestos will have been reduced from 5 million particles per cubic Mny-Jumj 1975, Vol. SO, No. 3 555 ' i i i ii t 1- i i HWBUI0011631 foot of air to 2 .fibers per ml (fibers longer than 5 microns). For asbestos textile plants, this reduction is about 15-fold {22). Present and scheduled standards claim only to protect workers against asbestosis, the disease for which the dose-response relationship is most quantitatively known. The British standards for chrysotilc and amositc asbestos, which arc comparable to the asbestos standard scheduled to take effect in the United States in 1976, do not purport to provide protec tion against increased risk of cancer (22,21). Previously studied cohorts of asbestos workers were exposed to time-averaged concentrations greater than 2 fibers per ml (fibers longer than 5 microns). Current studies of cohorts with time-averaged exposure on the order of 1 Tiber per ml (greater than 5 microns in length) may provide evidence of hazard at that level. In view of alarming preliminary findings of pulmonary fibrosis in such a cohort, the National Institute of Oc cupational Safety a.nd Health has suggested to the Department of Labor that consideration be given to further lowering of the-asbestos standard (25). The average brake mechanic is not aware of the potential hazard of ait borne brake dust. Nor is he quick to change time-hardened habits when warned of dangers if he cannot feel their effects. Nonetheless, sub stantial reduction in asbestos exposures during brake repair can be achieved by simple changes in technique, with the use of equipment already available in most brake service establishments. In view of the tendency of the accumulating literature to reveal cancer induction from asbestos at progressive ly lower levels of exposure, mechanics should be ad vised not to blow out brake parts and to use instead methods which create less airborne dust. The manufac turers of automotive friction materials could easily at tach a clear hazard warning to every item sold. The limited success of both the Baltimore and Washington studies shows the limited efficacy of volun tary compliance with health warnings--the shop managers and the mechanics simply do not have the same regard for a warning that they have for a regula tion. The margin of safety, if any, provided by the current asbestos standards has been sharply criticized as insufficient (26). While it is advisable that brake mechanics at least be warned of the potential hazard of their work, it is also apparent that blowing out brakes will be a common practice so long as health regulations permit it. Rf/erniccs 1. Cooper. \V. C., et al.: Asbestos--the need for and feasibility of air pollution controls. National Academy of Sciences, Washington, DC.. 1971. 2. Sclikuff, I. J., flaiuinond, F.. C., and Churg, J.: Mortality ex periences of asbestos insulation workers. In Proceedings of the International Conference on Pneumoconiosis, Johannesburg, 1909, edited by II. A. Shapiro. Oxford University Press, Capetown, .South Africa, 197(1, pp. 1 Sit -- tHC. >7. Stell, P. M., and Mctiill, T.: Asbestos and laryngeal carcinoma. l.aniet 2: 410-117, Aug 25. 1972. /. New house. M. I., and I hnriipsnn, II.: Mruilhehoma of the pleura antl'periioiiriim following exposure to asbestos in (lie lamdon area. Ur J Ind Mrd 22 201 -209 (1963). .5. I.ichcn, J.. and Pistawka. II,: Me>othelioma and asbestos ex posure. Arch Environ Health 14: 559-563 (1907). (i. Wagner, J. G., Slrggs, C. A., and March.md, P.: Diffuse pleural mesothelioma and asbestos exposure in the North Western Chape Province. Hr J Ind Med 17: 250-271 (1900). 7. Dalquen, P., Dabbert. A. K.. and I bn*. I.: F.pidemiulngic drr Plcuramesothelioma. Vorlaufigcr Hrriclit uber 119 Fnlleausdrm Hamburger. Kaum Prax Pncumul 23: 517-3.58 (1909). S. Murphy, R. L., et al.: Floor tile installation as a source of asbestos exposure. Am Rev Kespir Dis 104: 570-580, October 1971. 9. Sullivan, R. J., and Athanassiadis, Y. C.: Preliminary air pollu tion survey of asbestos. National Air Pollution Control Ad ministration, APTD 09--27. Raleigh, N.C., 1909, p. 32. 10. Harwood, C.: Asbestos air pollution from the wear of brake linings. Illinois Institute of Technology Research institute. Chicago, April 1972. "'//. Jacko, M.G., and DuCharmc, R.T.: Brake emissions- emission measurements from brake and clutch linings from selected mobile sources. F.nvironmental Protection Agency Report 68-0-t-(X/20. Ann Atbur, 1973. 12. Lynch, J.: Utake lining decomposition products.'J Air Pollul Control Assoc 18: 824-826 (1968). Jacko, M. G., DuCharme, R. T., and Somers, J. H.: Brake and clutch emissions during vehicle operation. Paper presented at Society of Automotive Engineers Meeting. Detroit, May 1973. 14. Hickish, D. E., and Knight, K. L.: Exposure to asbestos during brake maintenance. Ann Qccup Hyg 13: 17--21 (1970). 15. Hatch, D.: Possible alternatives to asbestos as a friction material. Ann Occup Hyg 13: 25--29 (1970). 16. Knight, K. L., and Hickish. D. E.: Investigations into alternative forms of control for dust generated during the cleaning of brake assemblies and drums, Ann Occup Hyg 13: 37--39 (1970). 17. Lee, G. L.: Removing dusts from brake assemblies during vehicle servicing--alternative cleaning methods. Ann Occup Hyg 13: 33-36 (1970). 13. Bentley, M. L.: Control of the use>f asbestos-containing friction materials. Ann Occup Hyg 13: 31--32 (1970). 19. U.S. Senate, Committee on Commerce: Toxic Substances Con trol Act of 1973. Hearings before the Environment Subcom mittee. Statement of B. Castlcman. 93d Cong. U.S. Government Printing Office, Washington, D.C., 1973, pp. 117, 349--350. 20. Guenther, G. C.: Emergency standard for exposure to asbestos dust. Federal Register, vol. 36, No. 234. Dec. 7, 1971, pp. 23207-23208. 21. Guenther, G. C.: Standard for exposure to asbestos dust. Federal Register, vol. 37, No. 110, June '?, 1972, pp. 11318-11322. 22. Lynch, J. K.t Ayer, H. E., arid Johnson, D. L.: The in terrelationship of selected asbestos exposure indices. Am Ind Hyg Assoc J 12: 598-604 (|970). 21. Hygiene standard for chrysolite asbestos dust. Ann Occup Hyg 11:47-49 (1968). 24. Hygiene standards fur airborne amosite asbestos dust. Ann Oc- cup Hyg 16: 1-5 (1973). 2.5. Key, M. M.: Reopening of asbestos standard. Memorandum to J. Slender. Assistant Secretary of Lalmr, Occupational Safely and Health Administration. Office of Technical Publications, National Institute fur Occupational Safety anil I leallh, Rockville, Md...March 28. 1974. . 2l>. Gee, B.. and lloulmys, A : Action on asltcslos. N EnglJ Med 285: 1317-1318, Dec. 2. 1971. .f I : ' J i I j [ l j I J . j I ! ' J ! } 15S Public Honllh Reports HWBUI0011632