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FILE NAME Brakes BRK DATE 1975 DOC BRK048 DOCUMENT DESCRIPTION Journal Article - Public Health Reports - The Hazards of Asbestos for Brake Mechanics The Hazards of Asbestos for Brake Mechanics BARRY CASTLEMAN LUCILLE A. CAMAROTA ALBERT J. FRITSCH SUSAN MAZZOCCHI and ROBERT G. CRAWLEY ASBESTOS is the generic name of a group of hydrated magnesium silicate mineral fibers There are two groups of these serpentine chrysotile and amphibole amosite crocidolite anthophyllite tremolite and actinolite Ninety percent of the world's asbestos production is chrysotile Reports of epidemiologic and pathological studies 1-4 reveal that occupational exposure to commercial asbestos minerals enhances the likelihood of a number of asbestosis and cancers of the lung pleura peritoneum larynx and gastrointestinal tract The time from onset of exposure to the time of clinically ap- parent disease is usually more than 20 years Cancer from asbestos is not limited to workers who handle the material There are also reports of pleural and peritoneal mesothelioma tumors rarely seen in the general population in persons with family or neighborhood or indirect occupational exposure to asbestos 4-7 Mesothelioma was the cause of death of a man who had regularly sanded vinyl asbestos floor tile 8 Under simulated conditions of this man's work a maximum asbestos dust concentration of 1.3 fibers per ml fibers longer than 5 microns was found in air samples passed through membrane filters worn by a person sanding vinyl asbestos 8 The type of asbestos now used in domestic floor tile is chrysotile same as that used in brake friction materials according to the Asbestos Information Association A case of mesothelioma in a brake mechanic has been reported 9 Commercial friction materials used in the United States for braking passenger cars and trucks contain an average composition of 50 percent chrysotile by weight 10 Asbestos has been used for brake drum linings disk pads and clutch facings for the past 50 years Jacko and DuCharme 11 estimated that the United States annually uses 103 million pounds of asbestos for brake friction materials and 4.5 million pounds in automotive clutch friction materials In 1968 Lynch reported that because of the heat of friction caused by braking almost all of the asbestos in brake linings is transformed to a nonfibrous mineral and a small fraction of asbestos escapes as free fiber 12 Jacko and workers determined that vehicles in this country emit 158,000 pounds of asbestos per year of which 11.2 percent is retained in the brake and dis- posed of during service 13 Brake mechanics have low and intermittent exposure to asbestos This exposure has been reported to be 0.79 fiber per ml weighted average fibers longer than 5 microns with peaks up to 7 fibers per ml when brake parts are being cleaned 14 The standard method for removing dust from brake parts is to blow it out with a Mr. Castleman an environmental engineer was with the Center for Science in the Public Interest when this paper was prepared he is now with the Maryland Public Interest Research Group Dr. Fritsch is director of the Center for Science in the Public Interest Ms. Camarota is an occupational health nurse District of Columbia Department of Human Resources Ms. Mazzocchi was a research associate Environmental Cancer Research Project Environmental Sciences Laboratory Mount Sinai School of Medicine New York City Mr. Crawley is a sanitarian Baltimore County Department of Health Tearsheet requests to Barry Castleman Maryland Public Interest Research Group 3110 New Main Dining Hall University of Maryland College Park Md 20742 254 Public Health Reports compressed air hose In 1970 several reports 14-18 14-18 described the levels of exposure of brake mechanics to asbestos alternative friction materials and specific changes in brake repair practices which would reduce the levels of exposure Baltimore and Washington Studies In December 1972 the Baltimore County Department of Health mailed a page mimeographed circular to about 130 establishments which provide brake repair service 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 contacted had either 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 including 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 186 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 catching and readable than the paragraph sheet used in Baltimore the leaflets were handed out by an occupational health nurse to the mechanics themselyes were mailed and followup to ascertain the degree of effectiveness was conducted by the same nurse who interviewed the repair managers The Washington study was also featured in a local television program at the time the leaflets were first handed out Preventive Health Care Dos & Don'ts For Yo What Are The H BRAKE REPAIR WORK Man with long experien mechanics should have preferably every six month To protect yourself and workplace against this stance . contain # Broke linings contain of asbestos fibe a srul body yoo CAN BE ; _ include a chest ray The pmhaynsi'csijaobn sanhdoulhids be into exposures | If you have or have had asbestos cigarette smokir a DON'T cluon brake drums with an air ho generated by this mett ously high S| ' The risk of lung can work who smoke and times greater than neither smoke nor wor number HazardousHazardous TO YOUR HEALTH oe er : =. larly bad If you smoke si , los workers one out * DON'T brush or by an deaths is due to lung How You May Contact Us raise dyst Please let us know what a taking what ideas you i offer and what problems | in following our suggestion your workplace sofer DO vacuum out all the DO wash the partsparts and keroseng keroseng , Contacts Center for Science in the 1 1779 Church Street NW Washington C 20036 | DO use a protactive > posure to asbestos + avoided Several comp ture masks disposable | 1.50 For informatio may be purchased + Center for Science in th at 202 332-6000 The risk of a seriou called asbestosis and body sites is about smokers and nonsmo work with asbestos At present it la not kn of exposure to asbe safe Even a small o dangerous in some a Asbestos related di takes 20 to 30 years f exposu ber coe me to ing with asbestos to time could result in t disease later on -District of Columbus Department of themes Resources Cocupational and Employee Health Program -" Center for Science in the Pubilo interest 4 ee edb To assure that students trained in brake repair by public vocational schools would learn proper methods health officials met with appropriate school officials in 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 percent 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 Predictably the responses ranged from annoyance to apprecia- tion Of the 65 places in Baltimore initially blowing out brakes 11 were using either 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 management 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 he need not be concerned with the matter The 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 year period ending in 1976 20,21 the U.S. standard for averaged exposure to asbestos will have been reduced from 5 million particles per cubic June 1975 Vol 90 No. 255 foot of air to 2 fibers per ml fibers longer than 5 microns For asbestos textile plants this reduction is about fold 22 Present and scheduled standards claim only to protect workers against asbestosis the disease for which the response relationship is most quantitatively known The British standards for chrysotile and amosite asbestos which are 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 23,24 Previously studied cohorts of asbestos workers were exposed to averaged concentrations greater than 2 fibers per ml fibers longer than 5 microns Current studies of cohorts with averaged exposure on the order of 1 fiber 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 and 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 airborne brake dust Nor is he quick to change hardened habits when warned of dangers if he cannot feel their effects Nonetheless substantial 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 advised 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 voluntary compliance with health warnings shop managers and the mechanics simply do not have the same regard for a warning that they have for a regulation 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 References 1. Cooper W. C. et al Asbestos need for and feasibility of air pollution controls National Academy of Sciences Washington D.C. 1971 2. Selikoff I. J. Hammond E. C. and Churg .: Mortality experiences of asbestos insulation workers In Proceedings of the International Conference on Pneumoconiosis Johannesburg 1969 edited by H. A. Shapiro Oxford University Press Capetown South Africa 1970 pp 180-186 3. Stell P. M. and McGill T Asbestos and laryngeal carcinoma et ee Lancet 2 416-417 Aug. 25 1973 4. Newhouse M. L. and Thompson H Mesothelioma of the pleura and peritoneum following exposure to asbestos in the London area Br J Ind Med 22 261-269 1965 5.5. Lieben J. and Pistawka H Mesothelioma and asbestos ex- posure Arch Environ Health 14 559-563 1967 6. Wagner J. C. Sleggs C. A. and Marchand .: Diffuse pleural mesothelioma and asbestos exposure in the North Western Cape Province BrJ Ind Med 17 250-271 1960 7. Dalquen P. Dabbert A. F. and Hinz .. Epidemiologie der Pleuramesothelioma Vorlaufiger Bericht uber 119 Falle aus dem Hamburger Raum Prax Pneumol 23 547-558 1969 8. Murphy R. L. et al Floor tile installation as a source of asbestos exposure Am Rev Respir Dis 104 576-580 October 1971 9. Sullivan R. J. and Athanassiadis Y. .: Preliminary air pollu- tion survey of asbestos National Air Pollution Control Ad- ministration APTD 69-27 Raleigh N.C. 1969 p 32 10. Harwood .: Asbestos air pollution from the wear of brake linings Illinois Institute of Technology Research Institute Chicago April 1972 11. Jacko M.G. and DuCharme R.T Brake emissions emission measurements from brake and clutch linings from selected mobile sources Environmental Protection Agency Report 68-04-0020 Ann Arbor 1973 12. Lynch .: Brake lining decomposition products J Air Pollut Control Assoc 18 824-826 1968 13. 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. .: Exposure to asbestos during brake maintenance Ann Occup 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. .: 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. .: Removing dusts from brake assemblies during vehicle alternative cleaning methods Ann Occup Hyg 13 33-36 1970 18. Bentley M. .: Control of the use of 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 Subcommittee Statement of B. Castleman 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 23207-23208 21. Guenther G. .: Standard for exposure to asbestos dust Federal Register vol 37 No. 110 June 7 1972 pp 11318-11322 22. Lynch J. R. Ayer H. E. and Johnson D. .: The interrelationship of selected asbestos exposure indices Am Ind Hyg AssocJ 12 598-604 1970 23. Hygiene standard for chrysotile asbestos dust Ann Occup Hyg 11 47-49 1968 24. Hygiene standards for airborne amosite asbestos dust Ann Occup Hyg 16 1-5 1973 25. Key M. M Reopening of asbestos standard to Memorandum J. Stender Assistant Secretary of Labor Occupational Safety and Health Administration Office of Technical Publications National Institute for Occupational Safety and Health Rockville Md March 28 1974 26. Gee B. and Bouhuys A Action on asbestos N EnglJMed 285 1317-1318 Dec. 2 1971 256 Public Health Reports