Document 9wZZZww9aXxqV9JgyaLJpyw5

DEPARTMENT OF HEALTH. EOUCATION. AND WELFARE PUBLIC HEALTH SERVICE CENTER rOR DISEASE CONTROL August 8, 1975 ' NATIONAL INSTITUTE TOR OCCUPATIONAL SAFETY AND HEALTH 3600 FISHERS LANE ROCKVILLE. MARYLANO 20632 Dear Colleague: This communication Is Intended to alert you to recently gathered Informa tion Indicating a potential health hazard for persons exposed to asbestos during the servicing of motor vehicle brake and clutch assemblies. On July 21, 1975, the National Institite for Occupational Safety and Health convened a meeting of government and university scientists, industry representatives, and labor union officials to discuss the present state of knowledge with respect to this problem. Data was presented by investigators from the Mount Siani School of Medicine in New York City indicating that workers engaged in the maintenance and repair of automobile and truck brake linings are exposed to potentially hazardous levels of airborne asbestos dust. Specific brake servicing operations studied included blow-out of automobile drum brake assemblies, grinding of used truck brake linings, and bevelling of new truck brake linings. Average peak asbestos air concentra tions for these three activities based on personal samples taken within ten feet of the operator were, respectively, 10.5, 3.75, and 37.3 fibers (>5 microns in length) per ml. An analysis of samples of brake drum dust revealed that almost all of the asbestos fibers found were shorter than 0.4 microns in length. Previous studies of the extent of asbestos emissions from automobile brake lining wear showed that only a very small fraction of the original asbestos content of the brake lining.is found in brake drum dust (Ref. 1-3). It was presumed that this is due to thermal degradation of the fibers during braking. The present findings indicate that enough asbestos is preserved to produce significant exposures during certain brake servicing procedures. The full extent of asbestos-related disease in brake servicing personnel is not known at present because this particular occupational group has not been studied systematically up to now. However, a review of the scientific literature on the association between asbestos exposure and mesothelial tumors of the pleura and peritoneum has revealed at least four cases of these rare tumors in persons who were employed in jobs involving automobile brake servicing (Ref. 4-6). DPMC-01702 LAM 008219 Page 2 For your Information and guidance, we are enclosing pertinent references, estimates of the population at risk, a NIOSH interim recommendation for brake and clutch servicing procedures, and a copy of the Department of Labor standard covering exposure to asbestos in the work place. The environmental studies of brake lining servicing operations outlined above together with observations of mesothelial tumors in persons so employed affirms the necessity for instituting and maintaining recommended control measures in this industry so that the health hazards of asbestos are minimized. Enclosures V. J. William Lloyd, Sc.D. Director Office of Occupational Health Surveillance and Biometrics DPMC-01703 LAM 008220 REFERENCES 1. Lynch, J.R.: Brake Lining Decomposition Products. J Air Pollution Control Assoc, 18:824-26, 1968 2. Hlckish, D.E. and Knight, K.L.: Exposure to Asbestos During Brake Maintenance. Ann Occup Hyg, 13:17-21, 1970 3. Jacko, M.G. and DuCharme, R.T.: Brake Emissions: Emission Measure ments from Brake and Clutch Linings from Selected Sources. EPA Report 68-04-0020, 1973 4. Newhouse, M.L. and Thompson, H.: Mesothelioma of Pleura and Peritoneum . Following Exposure to Asbestos in the London Area. Brit J Ind Med, 22:261-69, 1965 5. McDonald, A.D. et al.: Epidemiology of Primary Malignant Mesothellal Tumors In Canada. Cancer, 26:914-19, 1970 6. Greenberg, M. and Lloyd Davies, T.A.: Mesothelioma Register 19671968. Brit J Ind Med, 31:91-104, 1974 V DPMC-01704 LAIW 008221 ESTIMATES OF THE WORKFORCE POTENTIALLY EXPOSED TO ASBESTOS IN THE MANUFACTURING AND SERVICING OF BRAKE LININGS AND CLUTCHES Auto Mechanics Garage Workers Manufacture (original and rebuilding) TOTAL . 833535 67,679 6.657 907,871 SOURCE: Adapted from 1972 Census of Manufacturers, 1972 County Business Patterns, and Census of Population: 1970 Occupation by Industry (all are Department of Commerce, Census Bureau publications) DPMC-01705 LAM 008222 RECOMMENDED (INTERIM) PROCEDURES FOR ASBESTOS BRAKE AND CLUTCH SERVICING The National Institute for Occupational Safety and Health (NIOSH) has research underway concerning dust exposures during brake and clutch servicing. Due to preliminary data demonstrating significant asbestos exposures during presently used brake and clutch servicing techniques, NIOSH has reviewed t alternate techniques whereby asbestos exposures are reduced. The following are interim procedures recommended by NIOSH to minimize dust exposures. 1. If possible, an area shall be designated for all brake and clutch repairs. Entrances into this area shall be posted with an asbestos exposure warning sign as follows: ' Asbestos Dust Hazard Avoid Breathing Dust Wear Assigned Protective Equipment Do Not Remain in Area Unless Your Work Requires It Breathing Asbestos Dust May Cause Asbestosls and Cancer 2. During brake servicing, an air purifying respirator, either single use or vrith replaceable particulate filter(s), as approved by the Mining Enforcement and Safety Administration (formerly Bureau of Mines) or NIOSH, shall be worn during all procedures starting with the removal of the wheels and including reassembly. During manual clutch servicing, such a respirator shall be worn during removal and cleaning of. the clutch, pressure plate and housing assembly and during instal lation of the new clutch assembly. 3. Dust shall first be cleaned from brake drums, brake backing plates, brake assemblies and clutch assemblies using an industrial type vacuum cleaner equipped with a high efficiency filter system (>99% efficiency for 0.3 pm diameter aerosols). After vacuum cleaning, any remaining dust shall be removed using a rag soaked in water and wrung until nearly dry. Under no circumstances shall compressed air or. dry brushing be used for cleaning. 4. During arcing and riveting operations, an approved respirator, as described in (2) above, shall be worn. Grinding (arcing) machines shall be provided with local exhaust ventilation such that worker exposures are maintained at least below the 1976 OSHA asbestos standard (29 CFR 1910.1001).* At a minimum, the dust bag of the arcing machine shall be removed and replaced with the hose of the high efficiency industrial vacuum described in (3) above. DPMC-01706 LAM 008223 5. Industrial vacuum cleaner bags containing asbestos dust and cloths used for wiping brake and clutch assemblies shall be sealed in plastic bags and labeled with the following warning label printed in letters of sufficient size and contrast to be readily visible and legible: Caution Contains Asbestos Fibers Avoid Breathing Dust Breathing Asbestos Dust May Cause Asbestosis and Cancer j All asbestos waste shall be disposed of in accordance with the OSHA asbestos regulation, 29 CFR 1910.1001(h). During removal of vacuum bags, an approved respirator, as described in (2) above, shall be worn. 6. All floor cleaning in areas where brakes and clutches are repaired shall be done with the high efficiency industrial vacuum cleaner as described in (3) above. Grinding (arcing) machines shall also be cleaned with such a vacuum cleaner and any remaining dust wiped with a damp cloth. An approved respirator, as described in (2) above, shall be used during this cleaning. 7. Although adherence to the above procedures should minimize any contamination of work clothing, it is required that the appropriate portions of the OSHA regulations on asbestos (29 CFR 1910.1001(d) (3 and 4)) concerning special clothing, change rooms, etc. be followed. HOTE: Strict adherence to the above procedures should minimize exposures to mechanics during brake and clutch servicing. These are interim recom mendations and are subject to revision pending results of ongoing NIOSH research. * Section 1910.1001 of the Code of Federal Regulations was formerly Section 1910.93a. This change was noted in the Federal Register, May 28, 1975. Prepared By Division of Field Studies and Clinical Investigations National Institute for Occupational Safety and Health Cincinnati, Ohio DPMC-01707 LAM 008224 i+L`. , - *4 im< *t*-r* DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE cdc, niosh Minutes of Occupational Exposures to Asbestos Dust Froa Brake Linings Meeting July 21, 1975 "<r Attendees See Attached Proceedings - Dr. John F. Finklea, Director of NIOSII, welconed the attendees. He stated that the purposes of the neeting were (1) to consider preliminary data on asbestos exposure among brake lining workers anJ (2) to liscuss a future course of action based on thi3 preliminary information. i.'r, Finklea then turned the neeting over to Dr. Irving Selikoff of Mount Sinai-for presentation of sone of his work on this problem. Dr. Selikoff described the background for our current concern. The health effects of asbestos are well known. Hovrcver, the health hazard associated with asbestos in brake linings until recently has re.cci/cI little attention. It vas thought that the intense heat generated iron braking modified the asbestos and that brake lining dust contained insignificant amounts of asbestos fibers. hr. ilancuso in 19* 3 did :f describe asbestos-related health ' effects in the manufacturing of asbestos for brake linings but uoparently this caused little concern. In 1973, a case of mesothelioma was reported in a brake repair worker. II This stimulated a re-exar.inatloa of the problem. Dr. SelikofT consulted with "Tr. "levers of WAN, *'.r. Cefalo of XA2! and the Ford Motor Corupany and the groun at 'It. Sinai initiated a study to determine if brake lining workers uero exposed to significant levels of asbestos. Dr. Selikoff introduced hr. Langer of It. Sinai who reviewed the composition of brake linings and the breakdown orodnets thought to occur from heat generated luring braking'. Previous studies did not demonstrate asbestos fibers in the amounts or prevalence is indicated by the current studies- at !!t. Sinai However, recent studies at '.It. Sinai demonstrated typical chrvsotilo asbestos fibers along with a wile range of other forms of crystalline and fibrous materials. He emphasised chat the composition of brake linings nay differ, for examnle, brake linings in the iuS. and Great Jlritain and products here In the 1.S. may have undorvonc many changes over the yo.irs. This is particularly important 3ince recent data show that I'M of the new car market is node up of these innorts. Further research is needed to characterise the osbo tos DPMC-01708 LAM 008225 A. i J :i i i i 7 .Jfc7: -2- content of past and present dust exposures. It should be recognized also.that the health effects of other natcrials In brake dust have aot been studied. Dr. P.ohl from Mt. Sinai reported on studies nf asbestos dust expo sure-in autonobile repair shops in '.lent York City. Pea!; exposures cron 5-8 minutes duration were measured. Fiber counts, using the OS!1A method, were from 4 to 30/ml at 3-5 feet from brake druni cleaned with comoresseJ air. At 5-10 feet, counts ranged from 2 to 4 nl; at 10-20 feet 0.4 to 4.8/ml. Drums cleaned with a brush generated less airborne asbestos, 1.3-3.6 fibers/ml in the operators breathing tone. Eighty to 99% of the fibers as observed by electron microscopy were less t.um J.4 microns in length, indicating a much higher exposure to asbestos fibers than indicated by ontical microscopy. Workers encaged in grinding operations to renew brake linings were exposed to 2-7 onticallv visible fibers/nl. Those bevelling linings had high exposures ranging fro:; 3272 fibers/ml. Dr. George Wright pointed out that earlier studies showed that 1 to 3% of brake dust is fibrous asbestos. Dr. Lorimer of !lt. Sinai reported on medical examination of ,)3 brake repair workers with 10-40 years of exposure. A substantial number were reported to nave M-ray and ventilatory function abnormalities. Further studies need to be done in this area before anv conconlusioas on health- effects can be drawn. However, it was pointed out that at lca3t four cases of mesotheliona have been reported nationally among auto mobile renair workers and this lends urgency to the problem. Dr. Finklea asked for comments and recommendations for addressing the problem. Mr. Meyers suggested that several practical control measures are feasible nov. Indeed, these measures have been instituted in several shops. His union alerted its members via its newsletter and ucvolopcd posters to alert workers to the problem. Mar. Meyers emphasized c.i.it the employers with whom he worked were most cooperative. Employers were encouraged to use vacuum cleaning of brake drums and, where accessary, nasks to reduce exposure, llis union has made arrangements for continued medical evaluation of its members. lie emphasized the importance of union representatives having access to workplaces for observation of sanitary practices. Dr. George Wright, an industrial consultant, emphasized that manu facturers have a responsibility to ascertain what happens to their products after being sold to others. This problem represent:: a diffi cult orohlen for the manufacturer and for their industrial custom's. Dr. Wright stressed belief that the asbestos industry would cooperate, in every possible way. \>r. Wright war not totally surprised by the fiber counts reported and expressed the belief chat one night subsequently encounter the full spectrum of asbestos--related disc :se among ,;ria a:rs. Dr. Wright expressed concern chat conditions night Lo worse -mu DPMC-01709 LAM 008226 -3- I exposure.*: higher among some smaller businesses. Ur. Wright cautioned that the Influence of fiber size should be considered and t.iac any extrapolation to the general population be made with caution, lie urged that any subsequent investigations utilize the UICC classification and the inclusion of negative controls. Dr. Wright cautioned against over interpreting the occurrence of four ncsothcliona cases. Mr. Samuels of IUD urged that NIOSH: --- Notify the Department of Labor about this nroblcn; -- 'lake minutes of this meeting available to public along with a suitable press release; -- Notify other involved unions; -- Institute an appropriate national sampling program; -- Institute a program of surveillance and intervention. Other unions involved include: -- United Auto Workers Teamsters 1 -- American Federation of Government Employees -- Allied Industrial Workers -- Laborers International --- International \ssociation of Machinists -- American Postal Workers Union -- United Mubber Workers -- Amalgamated Transit Union --* Transport Workers Union of America -- United Transportation Union '!r. Samuels of IUD urged that everyone be informed of existing, easily applicable control measures. Mr. .icvcrs suggested any release on control technology be built unon their asbestos safety bulletin. Mr. Angelo Mefalo of IA* l discussed the need to infer:*. affected locals and union members in an orderly fashion, Mr. Cefilo ntncaJ t.s-c i i I DPMC-01710 j LAM 008227 4 the needed research nrogran should be planned and funded, lie offered his assistance in obtaining any needed- 3urjnort for this program. Dr. ?lancuso of the University of Pittsburg:! at the request of the International Association of Machinists conducted a pilot study of dcata records and identified in 1173 a mesothelioma case (proven by autopay) of a garage mechanic and another case of pleural mesothelioma in a nillright who was blowing out asbestos, friction-tvnc clutche. vita compressed air at a paper enmoany. !)r. !iancuso felt the nature of the death records vas such that other case-i of mesothelioma nay exist but are unrecognized. He spoke of the need to use this opportunity to develop an effective industrial medical surveillance system. Herb Northrop of Ford asked that any alert bulletin place this problem in perspective -- pointing out other recognized exposures to' asbestos. John Dement of DFSCI presented preliminary data fron a NIOSH study showing neak exposures of un to 5 fibers/nl during brake drum blowing. He also showed peak lead levels of approximately 4.5 ng/J-D during blowing operations. NIOSH olectronraicroscopic studies of brake drum dust also showed a predominance of small asbestos fibers with most fibers-being less than 1 nicronctor in length. At a plant renewing lined brake shoes, exposures of 20 fibers/ml (during grinding) and peaks of un to 10 fibers/ml during emptying of a drum containing old linings were -observed. Dr. Ueaver of API offered to communicate with gasoline stations and he supported further studies of the problem and emphasized the need to use appropriate controls of UICC film reading techniques. Ed Alnaugh of International Harvester urged preparation of a joint release. Paul Toth of Ford offered to help with suggestions on control technology and in disseminating information from NIOSIl on this matter to appropriate Ford Motor Company dealer relations personnel. John Horan of EPA pointed out that disc brakes release more asbestos into the general environment than shoe brakes. He stated that the EPA expressway roadside study could lcol; at asbestos levels along, a gradient avav from the expressway. Dr. Selikoff pointed out taut braking. Itself, nay be important and chat roadside studies should consider the effect of braking. Dr- 'kmcuso was asked to comment on the needed hcxlth studies. He suggested aa epidemiology study of the nortalitv experience of a cohort of unionized mrkers and their families. He emphasized need for excro.te care in the experimental design. He thought such a study should look for other cancers tntl occupational respiratorv disease; as well as asbestos--r:1 at ud ' Iso r.dors.- DPMC-01711 LAM 008228 It was emphasized that workers were exnosed to metals, plastic dusts (body shoos), solvents and toxic gases like carbon monoxide. i;r. `Inncuso reconnended clinical studies in the same pooulation of workers* He especially requested evaluation of so-called "nuisance dusts" which he claims nay be more harmful than novr realized, lie cmnh.1si7.cd need to look at workers who left the industry as well as those who arc still employed. !!r. Toth stress?t the need to ascertain the role of tobacco smoking in any studies. Others agreed with hie.. L'r. 'lancuso took, exception to the undue emphasis on the smoking aspects, to the exclusion of proper recognition of the magnitude of inherent health risks due co the chemicals.in dusts of the working environment. Pr. Selikoff suggested seven areas for urgent study: -- Analysis of brake materials utilized since 1040 using literature survey and laboratory analysis (EPA/11I0SH). -- Broad based national industrial hygiene survey to assess exposures for various occupational tasks (NIOSIi/OSUA). -- Epidemiologic studies of mortality experience of exposed workers from several sources (NIOSII). lie suggests this receive the highest priority. -- Further clinical studies of 1,000 workers including suitable controls (NIOSII). -- Autopsy survey of lung asbestos burden of exposed workers in auto maintenance industry (IJIOSII). --- Industrial hygiene measures to better control exposure (Joint effort of unions, industry and klOS'.I) . -- Education of workers to hazard and to use control measure* (DOL/kTOSK) . Dr. Selikoff suggested t_hat there be no delay in getting this program underway. Dr. Joe Wagoner of 2UOSH generally supported the discussed research program. He emphasized need for careful characterization of exposures to agents- other than asbestos and the need to assure that ii.:ited research funds are used to answer some of our major remaining scientific questions about the effects of exnosure to relatively low level.-* 06 short asbestos fibers. William Best of HCI offered his assistance .md asked whether or not a case-control study night be of some help. DPMC-01712 LAM 008229