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FILE NAME Brakes BRK DATE 1976 DOC BRK066 DOCUMENT DESCRIPTION Journal Article - Asbestos Exposure of Brake Repair Workers in the US THE MOUNT SUAI JOURNAL OF MEDICINE Vol 43. No. 3. June 1976 Printed in U.S.A. Asbestos Exposuroef Brake Repair Workers in the United States WILLIAM V. LORIMER M.D. ARTHUR N. ROHL PH.D. ALBERT MILLER M.D. WILLIAM J. NICHOLSON PH.D. AND IRVING J. SELIKOFF M.D. Introduction At least 900,000 people in the United States are employed as auto mechanics or garage workers 1 An unknown but large percentage of these workers regularly service brake linings Brake linings pose a potential hazard for asbestos exposure because they contain 33-73 asbestos 2-4 Jacko and Ducharme 2 have estimated that 70 million pounds of asbestos 32 million Kg are worn away from brake linings each year in the United States Much of the asbestos worn away around -90 drops to the road or is emitted into the atmosphere The wearing of asbestos linings is complex and for brief periods of time local areas in the lining surface have temperatures exceeding 630 the tempera- ture at which chrysotile asbestos loses the major portion of its water of hy- pe nt See droxylation and loses its characteristic morphology The bulk temperature OR Ore cannot exceed 350-400 for any length of time without decomposition of the Er : organic polymer binder material PegS$ at) Several investigators 2-4 have analyzed bulk brake dust for Pag chrysotile and have found weight percentages of between 0.3 2 to at most % 3 Lynch 4 reported percentages of 10 and 15 free fiber in two of fifteen samples Most of the rest were below % Personal and background sampling of workers engaged in brake mainte- nance work at the job site gives a more direct estimate of exposure During brake servicing the wheel is removed and all loose dust is RE removed from the drums and backplates Compressed air jets are usually used Fig 1 In a city survey in the USA Castleman et al 5 found that 175 out of 220 establishments used this procedure Alternates include vacuuming and wet brushing The brake lining itself may require grinding to remove irregularities or removal and replacement The new lining may require OTE considerable manipulation to fit the brake beveling edges and punching holes in the material for example As an alternative the brake shoe and lining IESE From the Department of Community Medicine and the Department of Medicine Mount Sinai School of Medicine of The City University of New York N. Y. 10029 * Presented at the XVIII International Congress on Occupational Health Brighton England Ua SaHee September 16 1975 This work was supported by New York City Health Research Council 2329 NIEHS Grant oe ES 00928 and NIH Research Training Fellowship National Heart and Lung Institute Grant HL doe sphomengs 03591 Dr. Lorimer and by The Ford Motor Company peal Requests for reprints should be sent to Dr. Willian Lorimer Environmental Sciences ae Laboratory Mount Sinai School of Medicine of The City University of New York N. 10029 = 207 pd, VAY PRT eg ted py ee AL 208 WILLIAM V. LORIMER ET AL 2 etaronies nalts FIG 1. Amuants.o worker cleaning brake drum with compressed air jet Note personal sampler on the right side of worker's chest 5,000,000 may be replaced as a unit A number of studies have measured exposure in summarized in Table I. such work and fiber counts reported are of In addition Boillat and Lob 8 reported values for various manipulations the lining material including punching holes for rivets and grinding Sampling interval is not given Fiber counts ranged from 0.3 to 29.2 fibers four of the nine values were over 5 fibers disease Asbestosis in brake liners has been recognized and Asbestos for 9 and instances of mesotheli- compensated in Great Britain many years Boillat and Lob 8 in workers have also been identified 10-12 oma garage who had performed lining examined 39 vehicular maintenance workers for about 2-2 hours a day for a mean of 8+ years They found two men service however provided no who may have had mild cases of asbestosis The study information as to the risk with longer exposures Present Investigation additional information on this subject we have in- In order to provide workers in vestigated asbestos exposure among brake repair maintenance in New York City and have initiated a clinical survey of workers employed the workshops studied ASBESTOS EXPOSURE Materials and methods Personal air samples were taken during lining maintenance work both on automobiles and trucks These were peak samples taken over 2-10 minutes ot ae ee vectra Ne a es ~ ae tmnt oo MEPLLett bs by ASBESTOS EXPOSURE OF BRAKE REPAIR WORKERS 209 $348.1 dumliotu ucoUsaijyB SOM] auity ays Sayeig UC sity SpUauLlory ULMOT ayvig nog UO BULYIOA UL Asbestos Operation duLnp WA XIOA TON Saynig Asbestos AUOP Su np auoz FIOM Auryeorg durnd snoy TABLE Measuremnts TABLE ur Measurements Measuremnts Brake Brake py Sampling he and Knight and blowing dust VAL side 90 blowing mechanic mechanic employed employed 800 806 personal cpelrsoounadl sampling dsaumrpilinngg sampling 2 eun/szaqt 2 arinsag | GEg 450 60g gto 450 L8 mornigafternon Re derBCP aves 4 aduDUqIy afterno S2aS A cat (QIU) T 06 -garage center center oog Ost Ost O8T O8T O8T Ost Ara} 09 180 09 paresMat duresayDigy PUAIA we s UI - TUT Lac Hatch seconds seconds pump i Knight dust personalpersonal yuonfpr saUOZ work jo dust Z) EDS (uaul eeAE from blowing blowing g) wos during (ual blowing blowing s9A0 during durjduins men Hickish omy) pue work say breathing breathing Boydurys secs zones Aaydurs ( durmnp from ures J EPP jo RE SOIAQSY staic sguydres jeuosiad futosadbay 91845 grin 91718 panos static adjacent bay WOIS O17e}5 aaIkGy he PEN MimeTOT punosyarqquaoeip Wwup averageaverage Avg SOME Jajuao Asp TUIA uo1juadg MyfOnTou oyouusr aYUPIOG Auimojq SZAUQ asvid FWUIAo_IG yFUsMnOp]g parystam at pur (2) NduYa) UStHouey yWAyU (L) (9) pur Yorey yg USDiOU y URED ras STT . i LT 4 MSUs SCSTTIIGE, oR OR RMA CPPR 0A STE PaaS en Oe EE 'ed 210 WILLIAM V. LORIMER ET AL during which the workers were performing certain tasks such as blowing dust from drum brakes renewing used linings by grinding and beveling new linings Background samples were also taken at varying distances and times The standard techniques for filter processing and fiber counting which have been adopted by the Occupational Safety and Health Administration of the US Department of Labor were used 13 Samples of dust collected in standard manner the were examined both by standard optical techniques fi- bers > 5 and by electron microscopy to give m of air and the results compared Bulk samples of brake dust were collected and analyzed by electron microscopy One hundred fibers were sized in each tive morphologic comparisons of the fibers with sample Qualita- ogy were made standard chrysotile morphol- Results Fiber concentrations for personal and background samples during blowing dust from drum brakes on automobiles are show extensive presented in Table II The values variation but the values at 3-5 feet are by far the highest with a mean of 15.9 fibers Fiber concentrations for personal and background samples during renewing used linings by grinding truck brakes are presented in Table III The mean concentration for the personal sampler was 3.8 fibers Fiber concentrations TABLE II Personal Automobile Brake Service Operation Distance Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes 3-5 ft 3-5 ft 3-5 ft 3-5 ft 5-10 5-10 5-10 10-20 ft 10-20 ft Background Automobile Brake Service Distance Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes Blowing dust out of drum brakes 10 ft 20 ft 12 ft 50 ft 65 ft 75 ft 0 min 0 min 5 min 5 min 7 min 14 min * Only fibers longer than 5 ...were counted by phase microscopy at 400 ConcentrationConcentration 13.8 29.4 6.6 13.6 - 3.8 2.0 4.2 0.4 4.8 Concetraion 0.3 0.8 0.2 0.1 0.1 0.1 for persc are giver To de chrysotil contrast are given determin A mean 20 of diffractio was giver alteratior granular ~ technique alteration silicate co CLINICA Materials 104 me examined City All ; and envir ASBESTOS EXPOSURE OF BRAKE REPAIR WORKERS TABLE III Personal Samples Brake Service Operation Concentration fibers Renewing used linings by grinding 2.7 Renewing used linings by grinding 7.0 Renewing used linings by grinding 2.2 Renewing used linings by grinding 4.1 Renewing used linings by grinding 5.0 Renewing used linings by grinding 4.7 Renewing used linings by grinding 5.6 Renewing used linings by grinding 1.7 Renewing used linings by grinding 2.5 Renewing used linings by grinding 2.0 Background Samples Brake Service 211 Operation Background to grinding used linings Background to grinding used linings Background to grinding used linings Background to grinding used linings Background to grinding used linings Distance 10 ft 10 ft 25 ft 25 ft 60 ft Concentration 1.2 1.7 1.0 0.6 0.2 for personal and background samples during beveling new linings for trucks are given in Table IV The mean concentrations were 37.5 fibers To determine the correlation between optical fiber counts and mass of chrysotile sections of filters collected as above were analyzed both by phase contrast optical microscopy and transmission electron microscopy The results are given in Table V. Ten samples of bulk brake dust were analyzed to determine the percentage of short fibrils defined as 250-500 ^ ^ 750-3750 ^ A mean of 83 of all chrysotile fibers were in this category A mean of about 20 of the total mass of the ten samples was chrysotile by electron diffraction Throughout the examination by electron microscopy attention was given to the morphology of the fibers A majority of fibers showed little alteration in the typical chrysotile fiber see Figure 2 Some fibrous and granular particles when analyzed by electron microscope microprobe techniques had structural and chemical characteristics of fosterite a thermal ~ alteration product of chrysotile Fig 3 Amorphous material with magnesium silicate composition was also found along with the fibrous particles Fig 4 CLINICAL STUDY Materials and methods 104 men members of a union of vehicular maintenance workers were examined in a preliminary study of maintenance workers in New York City All were volunteers The examination included a detailed occupational and environmental history medical history physical examination chest F er TEPRos Avies om s?hert he Reh ARTE eNO Ly | Sean = **** **** autor^5 autor^5 Cprenrens makabukas t sewmeager makabukas 212 WILLIAM V. LORIMER ET AL TABLE IV Personal Samples Brake Service Operation Concentration fibers Beveling new linings Beveling new linings Beveling new linings Beveling new linings Beveling new linings 31.7 23.7 32.7 72.0 26.3- Background Samples Brake Service Operation Background to beveling linings Background to beveling linings Background to beveling linings Background to beveling linings Distance 8 ft : 12 ft 12 ft 30 ft Concentration 0.6 0.5 0.3 0.3 TABLE V Automobile Lining Service . Operation / Light grinding of new linings before installation Grinding new linings before installation Blowing dust off drum with air jet Cleaning brake drum with hand brush Background to blowing out brake drum 10 feet away Background to blowing out brake drum 20 feet away Background to blowing out brake drum 65 feet away Comparison of Optical and E. M. Fiber Counts Optical Microscopy fibers 4.8 2.7 0.4 3.6 0.3 0.8 .1 Electron Microscopy g . 53.0 66.0 1.1 6.5 0.2 0.1 0.2 ray and pulmonary studies Three men were excluded from analysis because they had worked in a shop for less than 10 years Also excluded from analysis were nine men whose occupational history raised the possibility of other asbestos exposure Two men were excluded because of known chest disease The remaining 90 believed themselves to be healthy all either were currently working 84 or had retired because age 6 Occupational Categories General mechanics 67 Body workers 7 Undercoaters 5 Lubrication 42 Painters 42 Miscellaneous other crafts 8/0 8/0 ERIN ASBESTOSASBESTAOSSBESTOASBSESTOS EXPOSURE EXPOSUREEXPOSUERXEPOSURO E F OF BRAKE BRAKE BRAKE BRAKREPAIRREPAIR REPAIR WORKERWSORKERS WORKERS WORKERSWORKERS edrim i eis Arshuviiyt LN aaa ee her yeh Chrysotile FIGFIG . 2. Chrysotile 1 Chrysotile Chrysotile Chrysotile fibers fibers fibers frofmrom brakebrakberake drum drum dust aSTite gt ve Abele A Aevtend Aapiers pape neipiomae iecapineod FORE SmRikiep Fab pe 025 025025 Hen FIG FIG 3. A foster foster te fiber fiber fiber from from brake brake brake drum dust i: : an a OS 2 PT RTI VTE LITT EIT Te ee i re eR Rai ra : e fot 214 WILLIAM V. LORIMER ET AL 0.5 p FIG 4. Amorphous material mixed with chrysotile fibers from brake dust Sixty of the seven general mechanics did brake lining more than once a week for ten years or more The workers had a mean age of 48 -12 with 28 -8 years on the job years Results Clinical examination Findings on pulmonary examination were minimal There were five cases of clubbing and four instances in which fine rales were heard Pulmonary function Standard spirometry was performed on a Systems Research Laboratory screener The measurements used were FVC predicted FEV1 and as a more sensitive measure of obstruction in airways the FEF25 ratio FEF25 is the forced expiratory flow rateswmiatlhl 25 of the vital capacity remaining to be expired The results were classified into either restrictive obstructive combined or normal according to the schema given in Table VI the results are detailed in Table VII 29 had decreased vital capacity the percentage increasing with age and most markedly after 20 years from onset on auto work Table VIII The differences are statistically significant .05 > p > .02 Effect of smoking Significantly more smokers and smokers than smokers were obstructed Table IX X= 8.48.01 8.48.01 > p > .001 See note at end of the Table There was no significant difference however smokers smokers and smokers with among not significant respect to restriction X= .01 FVC FVC FVC * Note Pulmor Restri / restr and cor N For be Relati No Ob Re Co. Tc For res For obs Those ; ASBESTOS EXPOSURE OF BRAKE REPAIR WORKERS 215 215 215 TABLE VI Classification of Pulmonary in Function Vehicular Maintenance Workers FEV1 75 FEF FVC .30 FEF FVC < .30 .59 < FVC FVC pred .80 FVC pred = .79 FVC pred ./69 Normal Restrictive Restrictive Obstructive Combined Combined Obstructive Combined Combined Obstructive Obstructive Combined * Note all those with FEV1 < .75 also had FEF2 < .30 TABLE VII Pulmonary Function Abnormalities in 87 Vehicular Maintenance Workers with over 10 Years Experience Number Percent Restrictive Obstructive Combined Any abnormalities 14 165 32 375 11 13 57 66 TABLE VIII Restriction of Pulmonary Function by Year of Onset of Work in 90 Vehicular Maintenance Workers . Abnormal Total Before 1946 i restrictive 1956-65 1946-55 and combined Yes No Yes No Yes No 25 1 15 14 28 10 19 % 33 34 For before 1956 compared with 1956 and after X = 4.84 .05 > p > .02 TABLE IX Relationship between Obstruction or Restriction and Smoking in Vehicular Maintenance Workers Normal Normal Obstructive Restrictive Combined Total Subjects 31 31 14 11 87 Smokers 7 25353 25353 25353 25353 25353 Never Smoked 13 5 25 Smokers 8 11 5 5 29 For restriction X=== .01 N.S. smokers and smokers compared with never smoked For obstruction X= 8.28 .01 > p > .001 Those in the combined group counted as being both obstructive and restrictive 418 i. 418oe ih oi ale SRRi? 4-1 LMADT. pAne gosh, ry ry & y "Y i e 4$ JF JF JF ... ... A 9797 97 % ** - A 4 4 a TeA e RE x SBE ST LITE ETE DEPRES 216 WILLIAM V. LORIMER ET AL The relationship between pulmonary function signs of restriction and abnormal rays was investigated No significant association was found Table X Chest ray The chest rays were read twice by consensus reading using at least three experienced readers and categorized according to the ILO classification An ray was read as abnormal if fine or moderately thin irregular linear opacities were present s or t t 1/0 and pleural thickening was present a or more The prevalence of abnormal readings is given in Table XI Parenchymal abnormalities were present in 19 instances nine 1/0 six 1/1 two 1/2 and two 2/2 ray findings consistent with asbestosis increased with time such a trend is evident in Table XII This trend is statistically significant o cane TABLE X Relationship between Ray Reading and Pulmonary Function Tests in 87 Vehicular Maintenance Workers Pulmonary function Number of Subjects ray reading Percent Restriction 25 Abnormal 5 20 Pery Obstruction Normal 20 80 43 Abnormal 15 35 Normal Normal 28 65 30 Abnormal 8 27 Normal 22 73 * parenchymal fibrosis and pleural thickening For overall pattern X= 1.78 .50 > > .30 For restriction alone X== 1.21 .30 > > .20 For obstruction alone X= 1.50 .30 > p > .20 For obstruction and restriction compared to normal X= .08 .80 > p > .70 TABLE XI tk Ray Changes in 90 Vehicular Maintenance Workers with over 10 Years Experience Number Percent Parenchymal fibrosis Pleural thickening or calcification Both parenchymal and pleural changes Any changes 18 20 5 : % 1 % 24 27 kgoetr, TABLE XII te Ray of Vehicular Maintenance Workers by Year of Onset of Work Abnormal 1956-65 Yes No 1946-55 Yes No Before 1946 Yes No 3 14 10 33 14 16 % 23 47 * Parenchymal fibrosis ILO s t 1/0 and pleural thickening Xfor before 1956 compared with 1956 and after X= 5.95 .02 > > .01 The an and eve hundreds in brake these ope weighted peak val Much granular Detailed reported optical f intact ch exposure Many asbestosi results w expected Measu brake re averages fifths of 0.4 in 1 group of of ray restrictiv limited i therefore United S among su instituted We are i Automobile cooperation We wish son and D wish to exp Warshaw in Mrs. Diane ASBESTOS EXPOSURE OF BRAKE REPAIR WORKERS 217 217 217 Discussion The amount of asbestos brake material worn away each year is enormous and even if only a small percentage is morphologically unaltered then hundreds of thousands of kilograms remain Fiber counts in various operations in brake maintenance work show wide variations Certainly they indicate that these operations need more systematic evaluation both as to peak and timeweighted values Peak values frequently exceed the 10 fiber legal limit for peak values in the United States Much of the chrysotile is altered to other phases which may be fibrous or granular The biologic activity of these materials has not been studied Detailed classification and quantification of these changes has not been reported However even the incomplete correlations presented above between optical fiber counts and electron microscopic volumes of morphologically intact chrysotile is evidence that fiber counts are useful measures of asbestos exposure in brake repair work Many of the vehicular maintenance workers examined showed signs of asbestosis The prevalence both of chest ray changes and restrictive function results was significantly higher after 20 years of exposure than before a result expected after occupational exposure to asbestos 14 15 Summary and Conclusion Measurements were made by optical microscopy of asbestos levels during brake repair and maintenance work in New York City Both weighted averages and peak levels showed significant asbestos exposure Over fourfifths of the total number of chrysotile fibers in brake dust were below 0.4 in length and not visible by optical microscopy Over quarter of a group of experienced vehicular maintenance workers examined had evidence of ray abnormalities consistent with asbestosis quarter also had restrictive pulmonary function test findings While this preliminary study was limited in scope and was restricted to volunteers and its results cannot therefore readily be generalized to all brake maintenance workers in the United States the findings suggest that asbestos disease will be present among such workers and that appropriate control measures should be urgently instituted Acknowledgments We are indebted to the United Automobile Workers Local 259 New York City and to the Automobile Dealers Industrial Relations Association of New York City for their valuable cooperation in the conduct of the field studies in this research We wish to acknowledge the assistance of Dr. Ruth Lilis Dr. Susan Daum Dr. Henry Anderson and Dr. S. Alf Fischbein for their cooperation in the clinical and radiologic studies We also wish to express our appreciation for the valuable assistance of Ann Teitelbaum and Raphael Warshaw in cur laboratory studies and to Mrs. Frances Perez Mrs. Marcia Lorimer R.N. and Mrs. Diane Monahan in our field investigations 3 aa Seo oe che NRAAa a z aca RS Ae SEE ARN Se Aeon A ete aS ae ee Pd mat esA PR ke ty bry PronySo Senora Shure a yte e} hpearen alta ANE shee ys Malnga Bet ay oo Band AEE ed ba Ch miteitetw y May 218 WILLIAM V. LORIMER ET AL References 1. Department of Commerce Bureau of Census 1972 Census of Manufacturers 1972 County Business Patterns Census of Population 1970 Occupation by Industry adapted by J. William Lloyd 2. Jacko M. G. and DuCharme R. T Brake Emissions Emission Measurements from Brake and Clutch Linings from Selected Mobile Sources EPA Report 68-04-0020 1973 3. Hickish D. E. and Knight K. L Exposure to Asbestos during Brake Maintenance Ann Occup Hyg 17-21 1970 4. Lynch J. R Brake Lining Decomposition Products J Air Pollution Cont Ass 824-826 1968 5. Castleman B. Camarota L. A. Fritsch A. J. Mazzocchi S. and Crawley R. G The Hazards of Asbestos for Brake Mechanics Public Health Reports Vol 90 No. 254-256 1975 6. Hatch D Possible Alternatives to Asbestos as a Friction Material Ann Occup Hyg 35-29 1970 7. Knight K. L. and Hickish D. E Investigations and Alternative Forms of Control for Dust Generated during the Cleaning of Brake Assemblies and Drums Ann Occup Hyg 36-39 1970 8. Boillat M. A. and Lob M Risk of Asbestosis in Workers Employed in Replacing Automobile Brake Linings Schweiz Med Wschr 103 1354-1359 1973 9. McVittie J. C Asbestosis in Great Britain Ann NY Acad Sci 128-138 1965 10. Newhouse M. L. and Thompson H Mesothelioma of Pleura and Peritoneum following Exposure to Asbestos in the London Area Brit J Ind Med 261-269 1965 11. McDonald A. D. Harper A. El Attar O. A. and McDonald J. C Epidemiology of Primary Malignant Mesothelial Tumors in Canada Cancer 914-19 1970 12. Greenberg M. and Lloyd Davies T. A Mesothelioma Register 1967-1968 Brit J Ind Med 91-104 1974 Asbestos 13. National Institute for Occupational Ocupational Safety and Health Occupational Exposure to . 1972 : 14. Bader M. E. Bader R. A. Teirstein A. S. Miller A. and Selikoff I. .: Pulmonary Function and Radiographic Changes in 598 Workers with Varying Duration of Exposure to Asbestos Mount Sinai J Med 492-500 1970 15. Selikoff I. J. Churg J. and Hammond E. .: The Occurrence of Asbestosis among Insulation Workers in the United States Ann NY Acad Sci 139 1515985 Received for publication January 23 1976 THE MOUNT Vol 4 Porta JOHN T. 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