Document r6kw18OK89E9RDJ754M7YpVb0

FILE NAME: Phenolic Resins (PHR) DATE: 1982 Nov 22 DOC#: PHR007 DOCUMENT DESCRIPTION: NIOSH Report - Industrial Hygiene Summary Report of Asbestos Exposure Assessment for Brake Mechanics t C s i> PLAINTIFF'S I EXHIBIT ^ PDB7-105UJJ INDUSTRIAL HYGIENE SUMMARY REPORT OF asbestos exposure assessment FOR BRAKE MECHANICS REPORT WRITTEN BY: Dennis R. Roberts Ralph D. Zumwalde a DATE OF REPORT: November 22, 1982 REPORT #32.4* Industrial Hygiene Section Industrywide Studies Branch Division of Surveillance, Hasard Evaluations and Field Studies National Institute for Occupational Safety and Health Cincinnati, Ohio U S DEPARTM ENT O f COMMERCE NATIONAL TECHNICAL MfORW ATlON S E A V lCi STRINOMELO. VA ZZISI ABSTRACT "In order to define the extent of gee end pertleulete ealeelone iron automotive brekee (end d u t c h e s ) , e combination separation and storage collection eyetea wee devised. Unique emissions collectors for both disc and drua brakes end for a clutch were conceived, deeigned, and built as the main embodiment of thle instrumentation. The hardware was lnatallad on a vehicle which was then driven through various test cycles to deter mine the extent and type of brake ealsalons generated at low and high operating teapereturee. Typical driving conditlona, auch aa the Detroit Traffic Teat, ea well aa more abusive driving conditions such as fada tests, were included. Typical original equipment and aftermarket friction materials for both disc and drua brakes were used in the tests. Brake relines were made to simulate typical eonauaer-type practices. The brake eaisslons generated were removed from the varioua collectors and mass balances were performed. The particulates were processed and analyzed by a com bination of optical and electron microscopy to ascertain the asbestos content and the aebestoe particle else distribution in the wear debris. Comparisons of emissions froa new and used friction materials, disc and drum brakes, and original equipment ant aftermarket materials were made. Finally, an estimate waa made of the total emission of at. itoa by all of the vehicles in the country. on the average, more than 99.7 purcent of the asbeatoa la converted; ,thq contribution to the atmosphere la 5060 pounds, or 3.2 percent of the'total asbestos emissions. I n d u s t r i a l Hygiene Summary Report o f A sbe st os Exposure Assessment for Brake Mechanics (U.S.) National In st, for Occupational S a f e t y and H e a l t h , C i n c i n n a t i , OH 22 Nov 02 PB87-10 543 3 % MX fcpsteMt Ccorwe Ife'jr.'rt Tecfcfcd bferatfcn Sonrice I MTVIO' REPORT DOCUMENTATION I L A (*C *T MO. PACE '*"fnstc'ai.* Hygiene Summary Reporc of Asbestos Exposure Assessiwnt for Brake Mechanics. Report No. 1WS-32-4A J. AMU-* * } PB87 1 0 5 4 3 3MS L * 0*1 82/11/22 4. 0*t**O4i IWS-32-4A Division of Surveillance_Harard Evaluations and Field Studies, NIOSH, U.S. Department of Health and Human Services, - Cincinnati, Ohio Sac a s bx 9. is. ; p S M l T d general area air samples were collected and analysed for both Time elchted Average (TWA) and peak asbestos (1 3 )2 2 1 0 fiber concentrations to which bra<e mechanic would*likely be posed while on the Job. Of the six facilities examined. two were automotive brake service shops, three were municipal Stra*"*'and private fleet service garage.- Asbestos fiber content and site were determined from bulk samples. Of the 13 TKA's determined for mechanics, the NIOSH recommended limits 5 l0 A T i l l / ..... -*" Uibers^cc) greater than l> m l c t o m e i e j Y T r i c c o m M ^ ~ l.nerB wai exceeded I n -E However. even these were within the current ~n stanards. Ulth the"eTptlon of vacuum cleaning, levels near th S 10SH recoramended celling, which l%_Q*b flbcrs/c^. T os **T 1U llbers/cc. Js exceed e ^ Cwlce _y_nen coapresscJ sir w<^ - n authors recomme'^ t^.t where pos,lb. "ei be^dTsTgatej or " k e h reoalrs and servicing with posted signs concerning asbestos danger, \acuum cleane IqT i ed wlth h^gn efficlency perticul.te air filter * U" f' cleaning the brake drums, brake becking pU'es. sssemb 11.. snd clutch areas. A person! respiratory protection program should be initiated. 17 I HloTH-PuTlU^on7"siOSH-Author. NIOSH-Surv.y, Field-Study. WS-32-4A. Regton-5 , Asbestos-fibers, Asbestos-dust, Autoaobiie-repair-snops t . C0SAT1 fW*</C<we 11 AdUiVtilf SUM -- US ts. | m m i c m <T*t evu n. m*.* ni amoMAi. row trt rrn^, DISCLAIMER Mention of ...pony no... or prodotto dots not oon.titot. .n d .r.on .n t by t,. Mntiotul Inotitute for Oooop.ti.n.1 Snfot, nnd MoUt,. il ABSTRACT The National Institute for Occupational Safety and Health has conducted industrial hygiene surveys to characterise airborne asbestos exposures and work practices for brake mechanics. Personal and general area'air samples were collected and analysed for Time Weighted Average (TWA) and peak asbes tos fiber concentrations. Bulk samples were collected and analysed for as bestos fiber content and sise. All samples were analysed by optical (OPT) and transmission electron microscopy (TE.M). The TWA and peak exposure levels varied with the assembly cleaning methods and time required to perform cleaning. Eight of thirteen TVA's for mechanics exceeded NIOSH recommended standards of 0.1 fibers/cc >5 um in length, (fibers/cc) but all were within current Occupational Safety and Health Administration regulations (2 fi bers/cc). Fiber levels for all cleaning methods, except vacuuming, were near the NIOSH recommended ceiling, of 0.5 fibers/cc. Two of the peak sam ples collected when compressed air cleaning was used had fiber levels that exceeded the OSHA ceiling of 10 fibers/cc. General area TWA's were similar for all facilities (O.Oi to 0.2^ fibers/cc). TEM analysis indicated lower fiber concentrations than OPT in most samples and revealed that So' of the total fiber population was <5 u* long. The geometric mean chrysotile fiber sise was 1.7 ua length and 0.15 ua diameter. TEM analysis showed that 50' of the fibers were chrysotile, 20' forsterite, and 50v unknown. The data show excessive asbestos fiber exposures during brake servicing, especially brake assembly cleaning; therefore, vacuum cleaning systems and NIOSH ap proved respiratory protection are recomaended to reduce asbestos exposure levels within NIOSH limits. * 111 CONTENTS Abstract..................................................... iii Introduction................................................... 1 Brake Materials, Products, and Usage.......................... 2 Historical Development of Friction Products..............2 Requirements for Brake Linings........................ ...3 Types of Brake Linings and Manufacturing Processes...... 6 Brake Lining and Repair and Maintenance Practices History.... 8 Selection of Facilities Surveyed..................... 10 Description of Brake Servicing Operations.................... 10 Sample Collection and Analysis Methods....................... 11 Airborne Samples......................................... 11 Eulk Samples............................................. 12 Work Practices Characterisation.............................. 13 Compressed Air Blow-off..................................13 Compressed Air,'"Solvent Hist Blow-off.................... 13 Dry Brushing............................................. 13 Wet Brushing............................................. 13 Squirt-off............................................... 13 Vacuum Cleaning........... 14 Survey Results and Discussion................................ 15 Asbestos Exposure Levels................................ 15 TEM Fiber Characterisation.............................. 1" Bulk Brake Dust.......................................... 21 Trace Metal Analysis.....................................21 Potential Health Effects from Asbestos Exposure..............23 Summary........................................... 25 Conclusion.................................................... 26 Recommendations............................................... 28 Appendix A-Refejrences...................... ............... A-l Appendix B-Description of Individuals Facilities........... B-l Appendix C-Recomaended Procedures for Asbestos Brake and Clutch Servicing............................. C-l ' _ TABLES 1. Fiber Air Sample Results................................. 16 2. Comparison Between TEM A OpticalMicroscopy Analysis..... 18 ' 3. Fiber Site Data...........................................20 4. Trace Metal Analyses..................................... 22 iv INTRODUCTION One of the objectives of the National Institute for Occupational Safety and Health (KIOSH) is to evaluate environmental exposures of working popula tions through industrial hygiene field surveys. Accordingly, NIOSH conducted comprehensive industrial hygiene surveys to; characterize dust exposures resulting from vehicle brake servicing operations, make a thorough assess ment of work practices utilised, and document the types of personal pro tective equipment used. Of particular interest was the potential for ex posure to asbestos fibers which could be generated by these types of opera tions. Limited studies of workers involved in brake servicing have suggested - that their work-related exposures may be associated with asbestos-induced diseases.1 KIOSH estimates that a work force of 151,000 brake mechanics and garage workers in the l.S. is potentially exposed to asbestos. Potential exposures are a result of 125 million pounds of asbestos used annually in the l.S. for the production of brake friction materials.^ Besides asbestos, other materials (e.g., binders, friction modifiers, fillers) are used in the manu facture of brake linings, that can likewise have a potential for exposure. As noted in one study, 30 materials and/or compounds that make up the binders, fiber reinforcers, property modifiers, etc., were identified during brake lining manufacturing. 2 1 BRAKE MATERIALS, PRODUCTS, AND USACE Historic! Development of Friction Products* Tbe requirements of early automobile friction materials were relatively minimal. Passenger<ars were light and designed for low speed operations. Brakes were of an external contracting type and utilized a variety of mate rials; this included leather and impregnated cotton products which were commonly used along with wool and felt. In 1903 woven asbestos friction materials were first marketed in the United States by the Keasbey and Mattison Company of Ambler, Pennsylvania.5 Because of their superior heat resistance and durability they rapidly increased in use and soon dominated the market. The woven asbestos brakes continued to be the dominant product used in automobiles until about 1930. They typically contained 70l or more wire-cored asbestos y-.rn impregnated with drying oils, such as linseed and bituminous material. Molded brake linings were developed in the early 19C0's and gained increase ing use with the introduction of internal shoe brakes in 19-7- By 1940 vxr tually all automobiles were equipped with molded brake linings, although woven products continue to be used in trucks, heavy equipment and for spe cialised applications. The molded linings in use were cut to length, usu ally by the manufacturer, and mounted on brake shoes using rivets. Until the mid 1920's brakes were only mounted on rear wheels; however, with the developheot of internal shoes, four wheel mountings soon became standard. # As automobiles were designed for use at higher speeds, brake linings im proved in both quality and performance. Various new materials were intro duced as fillers, binders, and friction modifiers. In 194* bonded brake 2 linings were developed and soon accounted for approximately 40 of the orig inal equipment brake market. In addition, they rapidly dominated the re placement market because of the considerable savings in labor during instal lation. In 1965 the first disc brakes were introduced on American automo biles and rapidly increased in use. In 1975 virtually all original equipment cars had front wheel brakes of this type. However, because of less stringent braking requirements and the difficulty of adapting mechanical parking brakes to the disc configuration, the rear wheel brakes on 95 of currently sold cars are still of the drum variety. Requirements for Brake Lining? A constant or slightly decreasing coefficient of friction (CF) with tem perature up ro about 1000 F is. required for an efficient brake lining; CF values of from 0.30 to 0.45 re normally sought, lower values produce brakes requiring excess pedal pressure, and those with higher values are too sensitive to pressure and develop excess wear. Ideally, the desired frictional qualities should be mtintained throughout the life of the lining material. During braking, chemical and physical changes occur in the material at the braking surfaces. These changes may produce an increase (build-up) or a decrease (fade) in friction. Satisfactory linings will fade slightly upon repeated applications, but will return to their initial state upon cooling.^ % u. of th. li.in, l. dbvidu.l detirtbl, f.r contider.tion*. ..ever, hi, ...r re.i..c. . be ...<xi.d uiih th, t d , h ,, .f th. lihin, td ,1.., .ith . ..hc.i..h, reduction in the CF. ,, lt ,, ,, b, hF ellcvi"* * Iterctidh df th, br.k, linin, .. 3 rial to occur. Jftrolysis of the organic binders and thermal decomposition of the chrysotile fibers under braking provide the necessary continuing renewal of the lining surface. Tfee lining should be non-abrasive to the drum surface. In addition to caus ing rapid drum weac, abrasive linings score the drusis which, in turn, leads to a rapid wearing of the lining. Drusis made of cast iron and steel are common with steel being more susceptible to scoring. Since brake drums have a hardness of from 3*5 to 4*0 on the HOH (mineral hardness range of 1 to 15 in which talc is rated 1 and diamond 15 ) scale, virtually all lining materials used have lower hardness values. Other necessary or desirable properties of brake linings include: physical strength, dimensional stability, quiet operation, and safe and non-offensivt degradation products. Of the various properties desired in the linin6s greatest attention is paid to build-up/fade and recovery characteris tics. Wear problems are not as serious and can more readily be overcome with the materials available. Compounding Ingredients of Brake Lining^ ,^ ,0,1 ' To achieve the desired friction properties, a wide variety of ingredients are commonly used in the manufacturer of automobile brake linings. These iaelude: w Asbestos Asbestos is used for fiber reinforcement of the friction product. Chrysotile is used almost exclusively and comprises from 40 to 50 percent of the 4 brake lining. Fiber grades 4 through 7 are used, and occasionally, several sires are Mixed or even calcined to improve performance characteristics. Aaosite, crocidolite, or other amphibole asbestos varieties are not used because they are too harsh and tend to score the brake drums. Organic binders Organic binders are primarily phenolic type resins selected for high bind ing strength. Unmodified phenolic resins when subjected to heat usually become hard and brittle. To prevent this, linseed, cashew nut, or China wood oils or cresols are added. Rubber, which also finds use as a binder, imparts desirable friction qualities and improves the flexibility of the lining material. Friction modifiers Friction modifiers are added to achieve a desirable CF over all operating conditions. These aodifiers also produce a more homogeneous lining surface. Included among these materials are lead, sine, brass, cashew nut oil, graph ite, and oxides of iron and copper. Fillers ' Fillers such as rubber scrap, barites, clays, silica, coke, coal and other minerals are used. These also have utility in achieving desired friction properties, in some cases through action as abrasives to recondition brak ing surfaces. One major purpose of the reconditioning agents is to retard the formation of forsterite which may accumulate on the surface of the brake lining. Forsterite is - mineral not originally present in th brake ru-.tcrijl, but is created by dehydroxylation and recrystallication of chryso- tile asbestos at high temperatures. The hardness of forsterite (6.5-7.0 5 on the MOH Scale) is such that it tends to score and gouge brake drums and discs (hardness 3-5), degrading the. pre.aturely. Therefore, crystalli sation of chrysotile to forsterite is an unwanted effect. Curing agents Curing agents and/or accelerators are used to assure that appropriate che.i cal reactions occur to produce the desired brake quality. Tvres of Brake Linints and Manufacturing Processes In the k i n g of different types of brake linings various nufacturing processes are utilised to achieve a wide range of potential applications. These include: Wired Back These are made by a calendcring'precess in which puttv-like stock is formed into a ribbon about a wire backing. The wire reinforcing serves to maintain strength during the curing process. Furthermore, as linings of this type are invariably riveted, the wire reinforcing provides long tens structural strength and prevents shearing of the lining at .the rivets during braking, linings of this type were extensively produced prior to World War II. They are in little use today. Extruded Linings These are nuf.ctured by extruding the soft plastic stock through an aPPro. priately'sixed rectangular orifice. To .ininice structural weakness in this lining, curing agents are added to produce a hard inflexible finished pro ducts. 6 Sheet Linings These 4re laminated structures formed by winding a 0.001-0.002 inch film of stock about a hot roller. Since the fabrication process is a relatively expensive one, linings of this type are not commonly produced for general use. Dry Mixed Types This process involves the dry mixing of various ingredients capable of pass ing a 200 mesh screen, and then molding the lining under pressures of from 1000 to .>000 pounds per square inch. The resulting lining is among the most heat stable of friction materials in use today and obtains wide use in the ^ manufacture of brake blocks for heavy dut> service. Millboard Type ' The manufacture of this type of brake lining material is by a process simi lar to that utilized in the paper industry. Vet stock is formed and passed over rollers with various drying and baking operations producing sheets of uniform lining material. The equipment for producing such materials is expensive, but the volume of production leads to an economically produced molded lining. 7 / I Il w a k e l i n i n g r e p a i r a s p h a i n t e n a n :e p r a c t i c e s h i s t o r y To 4 large extent the changing character of brake lining materials has led to changing work practices and differing asbestos exposures over the years. Fro. 1920 until about 1930, when braking was done through the use of exter nal brake bands nade from woven materials, the predominant exposure to as bestos would have come from the cutting and fitting of the woven lining material. Most likely the airborne fiber concentrations were considerably less than those developed in later years when machining of molded materials was common. From 1927, when internal brake shoes were developed using molded l.nincs, until 194? when bonded brake linings were introduced, all internal brake \ linings were attached to shoes using rivets. The lining material for use in the replacement market would be precut to appropriate site for various brakes or obtained from rolls of indeterminate length. The Precut segments would usually be predrilled at the factory for rapid mounting on shoes. In some circumstances, however, drilling for the rivets and bevelling would be done by the mechanic installing them. The use of rolled linings required cutting the friction r i a l to shape, drilling holes for rivets, and bev elling the edge, appropriately. Under the latter circumstances, asbestos exposure to worker, could be considerable. Even when shoe, with predrilled * and bevelled linings were installed, the processes of punching out the rivet, on the old shoe, and riveting on of the new shoe, would give rise to greater exposures than that accompanying the use of bonded linings. kith the introduction of bonded lining, the need for drilling, facing, or grinding operations during installation decreased significantly. However, J 8 for a short period of time, in the aid-1950's when automobile shoes were first installed with a fixed anchor, soae tapering was necessary on uniform thickness bonded linings to achieve a proper fit. Previously, the end of the shoe opposite to that of the hydraulic cylinder could be aechanically adjusted. Shortly thereafter, tapered bonded linings were available from the factory. Subsequent to I960, considerably fewer bevelling or grinding op 'at.-.'. .*e performed by an automobile mechanic replacing brake liniu ... Curing replacement of internal shoe brakes coaaon practice was to remove the brake wear dust froa the housing by air blowing or brushing. After 1970 increasing awareness of the hazards of asbestos and its presence in br.kelining dust led to wet brushing, wet wiping, dry brushing, or vacuuming work practices in some brake servicing facilities. However, even today such improved work practices are not universal. In the 1930's and 1940's most automobile shops were relatively small and eost mechanics performed all automobile maintenance and repair activities, in recent years, however, there has been an increasing tendency towards specialisation, with shops existing for brakes and front end work exclu sively. Here, while asbestos exposures during brake work on an individual job may be less than those of previous years, some workers are exposed for considerably longer periods of time. 9 SELECTION OF FACILITIES SURVEYED The purpose of the industrial hygiene study vis to investigate and char acterise contemporary dust exposures resulting from vehicle brake mainten ance and repair operations taking into account the work practices utilised. Therefore, it vas necessary to locate facilities where a variety of brake servicing techniques vere used as well as where there were differences in the number of vehicles serviced. Two of the six sites selected for the investigation were automobile brake service facilities which performed up to 45 brake jobs per week at an average of 5 minutes per vehicle. The re maining four facilities serviced both autos and trucks and performed from 5 to 45 brake jobs per week. The service time varied depending on the type of vehicle. Detailed airborne dust sampling surveys were conducted at each facility. ' DESCRIPTION OF BRAKE SERVICING OPERATIONS The servicing procedures found at each facility-were basically as fellows. Tho vehicle is driven into a repair stall or bay for a brake system exami nation. Pending repairs, the wheels are elevated, removed, and then inspect ed. Loose dust'is cleaned from the drums and brake assemblies by vacuuming, wet or dry viping/brushing, using compressed air, or a combination of these methods. Parts are then replaced or repaired as needed and the brake system is reassembled and adjusted. Test driving the vehicle for proper fitting and adjustment is the final phase of the servicing operation. A brief de ' 0 scription of the individual facilities is outlined in Appendix B. 10 SAMPLE COLLECTION ANO ANALYSIS METHODS Airborne Samples Personal and general air sasiples were collected at each facility on dif ferent occasions during a 3-year period. Brake servicing operations and areas not in the immediate vicinity of brake work within each facility were monitored to provide overall asbestos exposure data. Personal air samples were collected in the breathing rone of the brake mechanics using plastic cassettes containing Millipore Type A.A, 37 millimeter (sun) diameter, O.b micrometer b s ) pore site, membrane filters. The samples were operated at a calibrated sampling flow rate of 2.0 Liters per minute (Lpm). The filters were changed periodically during.the work shift to prevent particulate over loading on the filter. Time-weighted average (TVA) fiber concentrations were determined for the time spent performing brake service, and peak con centrations were determined for time spent cleaning brake dust from drums and assemblies. Samples for personal peak exposures were collected using Cast pumps calibrated at about 11.0 Lpa using identical media as above. At facilities C, P, and E, a 2.0 Lpm sampling train was used for peak sam ples. All analyses of the membrane filters for asbestos fibers were con ducted by the'author in accordance with the procedures outlined by the Occu pational Safety and Health Administration11 and the SIOSH Manual of Analyti cal Methods P&CAM *230.12 These procedures require the counting of fibers greater than 5 urn in length and with at least a 3 to l length to width aspect ratio utilising phase contrast optical microscopy at a magnification of 400-450X. Concentrations are expressed as fibers per cubic centimeter ot air (fibers/cc). 11 undo., P L . L o . ...h * " " 'h"" ' fiber concentrerions, determined bp ih. .p.ic.i =ntint ..iho-, .ere enei,,ed . .le.tr. diffrection (SIE) end ...re- di.p.r.iv. E - r ,, ( B L U . Semple. - r . < * *' " ,, p e c t retto) .i=.d L o . t b end die.,,er. V `th "* *U "" eerved fiber, f.r i d l ! l i - *" - "m " divido., fiber. .. determine .bete .le.en.el W * - "" .,,d E ! elementel .P. . r reti.. ..re ...per.d .itb r m l . r . - * > . ,, ,, . C i l e end forsterite bt.ined fro. tb. ... S.epl, preperetion end enei,!, vere P e r l - e d U t . ^ in the Te.bnicel .Per. -Pe t L o - Envirotorentel Stmdie. .f 1 * Per.i.olet, Eepo.or,-. J Cenere, ere. .empie Tor t r e . , - t e i - . - -- pene,,, otre colle.ted me, ledili,!. - 1 St.P.ex TVP. - b.pb volo., .empier . < l f " ^ "n"" '"* , ...Pline trein end 11. re,, lib. .be. ed !r .bette " ' ' Sem.,.. ..re enelf.ed 1 ' * in .cord,, vitb ,b, * K " < S* `" 2~ ' S '!C' " 5366.14,13 uH: Saturi J i ; . bf breke veer d o ., .e re 1 . - * - * eehicle . . . - - 1 . " fl" ed bf 1er b . r . . t . r i . . t i e b end i d e n t i f i e . , ! . , f l i b r o .. end for determinetion of lib e r != d i.tr ib o tio n . 1Z WORK PRACTICE CHARACTERISTIC?; During the surveys considerable emphasis was placed on detailing work pro cedures during brake servicing in order to document the types of cleaning practices (e.g., vacua, compressed air, brushing) used in replacing brakes. As previously described in the section -Description of Brake Servicing Operations- the brake servicing work practices utilised were similar for all facilities surveyed; the major difference observed was the methodology utilized for clean-off of brake wear dust from the brake-shoe/backing-plate assemblies. There were si* different types of clean-off methods observed during the study. Those six methods are described as follows: 1. C a r e s s e d Air Blcw-Off. a compressed air stream was used to blow away brake wear dust from the brake assemblies and drums. 2 - Compressed Air-Stoddard Solvent Hist Blow-Off. The same as *1 ex cept a spray gun containing Stoddard solvent was used to produce a solvent mist for blow-off. 3. Trv Prushine. Brake wear dust was brushed away with a small utility brush usually l inch in diameter. 4* Brushinc- Basically the same as dry brushing except the brush was kept saturated with a liquid such as gasoline, water, or 'Stoddard solvent. 13 5. Sauirt-Off. A liquid ,quirt-bottle containing water was used to wash away brake dust. This was followed by drying off assemblies with a cloth. 6 . ...... A .Hop typ. vl,h * K P 1 filter', ... ..A " eo.bin.eio .ith eo.pr...d >ir. IHi. induced . br.k. ne.p.el.tion cylinder .He. eo.ple.ely e"'1" ' 1 U ,, br.ke-.Hoe/backing Pl*>............ .. Th' " h* " le pr, . ,, d .it noetle f i d in.ide the-enelo.ere to bio. off tb. br.ke d o ,., .HUH . . . iB .e d i.te ly dr.'.n into .He - rete v.cuu. H... ... . < to ="" fr* ` MP" <r" '- "HEPA: High Efficiency Particulate Air Filter - 90-7' enc> for 0.3 wm diameter aerosols. 1,, Methods 1 to 5, and especially 1 to 3.- the brake dust has the Potential to enter the ambient air of the facility. Conversely, in Method 6 the dust is contained by the HEPA filter which may be _______ A the vacuum cleaning system for disposal. 14 I SURVEY RESULTS ASP DISCUSSION nhestos E n sure level_s n e ,, p u d - - * - k p" ""1 ;n ,, d background area samples collected during the study ^are Table I. The TVA c o n c e n t r a t ^ o n s j ^ d j r w j . ^ t ^ ^ ^s_ r ^ ^ ^ r r ^ r n T T o r f i ^ s / c c . The TWA and peak fiber :;r r r : -- .-- ~ --- - 7 * ,,,ud. u . -- -- M . or, 1..- * * ** u * - ...u - 1 . d P d - r d I*, .* -- * - -- ,h'P S ' * `"u ; ' ** " " " spent s t r u c i n r shift differed among the mechanics; likewise, differences in cleaning methods ( *g > j dii . . s (e . distance from brake housing to breathing . techniques (e.g., the floor, mechanics who dropped the brake orum tion, there were some mechan , ns at each , nf brake dust. Environmental condition c.u.iP( tirborne . ' "> f b" k' " * ,, brake service ....... back_ IS r i i i i Tabi I r ib e r A ir S a *p !a R f i v t l i f a r Braba A aea4 |y C U m -O fr R ( M i C lrw lra N tlM ( v iA ic e i A ir C A # frie4 A ir Canpterar! A lt A ir C o e |irrM rl A ir CunpreaaeA A ir Canpreaaef A ir C o A ftm rl A ir ((W fre M fl A ir* Tolu en i f ila i T o lu en i U lt i C (W |frM A | A ir* fa ! rm n i. C A H 'It # ! A ir* Sa I v ia i M iai Dry Brutti B e r Bruni M rt I r a .t i Mei BrwaH r a c lllrr Irrv tic i A A A A A B 9 > tu rU ft iM flH M e d a n le #1 H edanle f i H**eban|c I I H edanle f i Herbante f i H ed an le f i N erb iate f i tlrrlm n lc f i He lia n te f i a Herbante f i a Herbante f i a Herbante f i a Herbante f i c H ed anle f i c Herbante f i a H ed anle f i P H erbanlr f i D Nerbante f i a Herbante f ) P lb e ra / Pent fa ro a u re a SaapU T lv i* ") i .ii 100 0 .14 4B 0 .1 ! 14 0 . 44 16 1 .4 9 70 1 .0 4 40 0 .1 1 44 1 4 .) t J0 1 4 .0 0 10 Sapp ia V a l a n (L ite ra } 1 .0 4 .1 4 .1 i.i 7 .) IO ! 0 VI 4. 1 0 .7 ) 0 .1 } 0 .4 1 0. Jt 0 .1 1 0 .1 1 I.II I .I I 0 .11 c .u 40 *} )0 100 no in o Ilo 100 440 440 4 .0 0 .0 ) .] Il 71 17 1 .0 * .o 10 i* ll< tM i i a l t * ( I t i t Nerbante f i 0 .)4 00 30 Rat C la a a l| I a*:*i a C l e M t A l r 0 .0 0 110 1 V acu i C le * A lA | t 0 .0 ! |;r> 1 r Herbante f i 0 .0 1 I/O 1 * l i b e r a *4 y * 1 t e n g tb f**r c a b le r e t tl* f < r r ! a le . 14 llM-UflfMel Avera** i^Aiutr (a ) petto! of line A.ioplrd, TWA C ib e r/ re* Capoaurea** S a n p le S m .1 . T ln V .IU M (H ln .) d it o .) C ib e r/ e r* sa rn Tin a C o a c c n c c # C lo n i talu n a 0 .0 1 1)7 704 0 .0 1 ) 100 100 0 .1 1 71) MI 0 .1 0 m 104 0 .1 0 710 111 0 .0 0 777 44 0 . IT 110 MO 0 .1 ) 9 10 0 .0 1 o .o ; 0 .7 0 0 .1 9 0 .1 ) 0. ! 0 .14 0 .1 1 )* ) 111 1*7 701 MI 11* 11) 111 0 .0 1 IO Il 0 .0 4 MI 1*4 MI 1*7 MI 110 1 )7 0 .0 ) 0 .0 7 0 .0 ) 0 .0 7 0 .0 7 0 .0 7 0 .0 4 7)1 1 )1 4M )I7 HO no HO MI SO 0 .01 IH CI 44 71 714 910 *10 770 >*U MI * ' \ ,, - pot.ntt.lly P . d to tto -- t ~ - " " ,, . ,, a Of O i. - c l " " ' " ** * 'h' v . rk ,it., . . W ~ ,h. r k . . . " " fr" th' -- " ' "` h " > " " those .hs. ,h' " **" . ,, L o t o d for trsnsoissfo. . 1 TM ..r..' " ) Sa.ples -ere random > .lysed for < hv lencth and diameter and 10 iieias with fibers site > (fihers/cc) were determined . Mliplt l,, addition, fiber concentrations (fxbers/cc) eeach sample. concentrations were con . fibers ind fibers > 5 w xn length. Tnese for total fiber reported m those found bv the optical microscopy met o ton.....*.!.M .f f i b . r > S - ` ,,oi. =.>. k; , ; ; " ea^ ic,, !CCP!. .... - le"i,h doterctnod b. T,, , differ..* ,,,d.- Us. . * - "5"U "f reparation for TEM* S . . F U p.r.`.`. TM "h l ,, -- ..... - ~ * ,,h do! fiber ....... - n -- " * " " " Ch .... icre.P>' -- - *-- ' flb,, , to..,. ceneB,r*,in- S-- " * ooio.U.ef r...i, ,, . h o d . ... .< th. i f . ... ; m t i ,, ,, t h . ... * th. di.P.r> " ,h. conc.,r,,e". CM * 4 e ..e .. r ..U . ,, dootth, , . 1 < " , ,, ,, J J h. .too,.4, ..*,*> *<* ' (B0 , . . . o . . u . . ^ f i b . r . . ^ " `h " ' " ,h* " S " ` 17 00 , I n t i J I 4 Fibers observed by TEM were identified utilising SAED end EDXRA. Approx imately SOX of the fibers analysed by SAED could not be identified due to ambiguous diffraction patterns. About 30'X of the fibers were identified as chrvsotile and approximately 20X as forsterite. The presence of fibrous forsterite was probably due to the dehydroxylation and recrystallisation of chrvsotile as a result of high temperatures (>650 C) encountered during braking.1'* Some of the fibers which revealed ambiguous diffraction patterns appeared.to have crystalline structures similar to both chrysotile and forsterite (probably a transition intermediate ) while others were too small for diffraction analysis. EDXRA was performed on the fibers to confirm the SAEP analysis that was made for the chrysotile and forsterite fibers. Some of these fibers which gave ambiguous SAEP patterns indicated magnesium, silicon, and iron in various elemental ratios typical of asbestiform miner als. . As shown in Table 3, when a fiber sice distribution was performed for all airborne sar.ple fibers observed ty TEH, a geometric mean length of l.W' Vim and a geometric mean diameter of 0.14 ym wore determined. Likewise, for those fibers identified as asbestos ichrysotilc) a geometric mean length and diameter of 1.70 urn and 0.15 ym, respectively were determined. Bulk samples of brake wear dust were analysed by TEM in the same manner as the airborne samples, identification was attempted on all fibers usxng SAED and EDXRA. Approximately 70l of the fibers analyzed by SAED could not be identified due to ambiguous or the absence of diffraction patterns. ErxRA was performed on all fibers observed with elemental analysis being success- 19 h i SAMPLE n r c _______ _-- Airborne Sample* (Chyaotlle Fiber Only) Airborne Sample (All Fibers) Bulk Brake Dust (Chyaotlle Fiber Only) Bulk Brake Dut (All Fiber) o TAIU.E 3 Brakr Dust Fiber Sire Data* Number of Fibers_ 151 Fiber Diameter tU*o. Mean 0 .0 6 -1 .0 0.15 (m) . (1*0 . Std Ocvft* 2.36 52) 0.06-1 .0 0.14 B 0 .0 6 - 0 .IB 0 . 10 2.17 1.51 Number of Fibers 151 523 8 Fiber Lenftth (in) Ceo. Std Dev 2.49 2.03 109 0 .0 6 -0 .2 9 J 0.08 , 1.53 109 Electron Microscopy. M l fiber sire data determined by Transmission * Standard Deviation 1.15  . .* - ,.< ... rf ,b, fiber* obser. d -- rar v : ; ; ` i u , . U . n t i f W > * " " ' ' ' ,h, ,,satin, .ere . M r <-- ' <"M i > " '"knC*" ''7'K ' on*,..,........ be internediat* r.crf .tainted f . -- `J . forsterite. addition. * *`=' *" " ,,.Seb indicated teneuhat .b.r.er iee.eb. (..-! " "* aveller diameters (0 , b - 0 , 0 urn v*. O.Ob-,, on, than ,bo,, observed the airborne ample* in Table Trace X etal Analvso* 1 a n - U s e s were performed on airborne samples collected at Trace *etal *rwl>s*5 c , . . c p ......................It* reported in Table 4. Samples Facilities B, C, P , anu Ban_ ,r, ,,.l,-.d f M tb. fnU.ui.. * . * '" ' ...... ,, cal i i . * - detection * S . O u , . . 0 U , 0 , U i ,*r* **"- ` .,lTtl, . neted in Tebi, d . M - - 1.0 .. rrr ...rle. re,re..nel) . . ,sii, er f u n d in tree. amounts, *"a BCn~ * os(u cr M P S H petal concentration (Pb, tba, exceeded OSH.t or '*" 1 exposure ' standards, The rang, of concentrations for all faciUt.es uere. . W- ^ V.. ... .,.,.-.5 . ^ ............. - \ 21 J I .t* Table A Trace M etal Analyaes f 1 * l-'-* (V '+ POTENTIAL HEALTH EFTECTS FROM ASBESTOS EXPOSfRE The human toxicological significance for the inhalation of chrysotile as bestos fibers is well documented; and instances of mesothelioma in auto i^pixr workers have been identified # ^ In a detailed examination of 90 union vehicular maintenance workers in Kew York City,* with 10 or more years of shop work, 29? had decreased vital capability; the percentage in creased with age and most markedly after 20 years from the outset of auto work. Many of the workers examined showed signs consistent with asbestosis, with observed changes noted in chest x-rays and indication of restrictive pulmonary function. The prevalence of these changes was significantly higher after 20 years exposure, a result expected after occupational exposure to as.bes.tos.1 0 ' Inlike chrysotile, the health effects of exposure to forsterite, or transi tion series fibers (chrysotile'forsterite) with altered crystalline structures are not well documented. In studies by Davi. s and Coni. am, 2 0 ana. Koshi"* in which fibers of chrysotile, chrysotile/forsterite, and forster ite were injected into the pleural and peritoneal cavities of mice, the results suggested varying degrees of toxic effects. Fiber implantation ani mal studies conducted by Pott, et. aI.2~ ,2`, ard Davis, et. al.24 suggest that the morphology and size of a fiber, regardless of fiber type, are re sponsible for its carcinogenicity. Likewise, Stanton, et. al.2a suggests that fibers <1.5 u in diameter and >6 urn in length pose the greatest risk in producing pleural sarcomas. These studies tend to suggest that the phy sical morphology (size dimensions) a'.d to a lesser degree chemical 'and surfee: characteristics of a fiber are the determining factors for inducing 23 , `J L v i . ,,1.,o,lobi ff,, The precis fi*. * ! > " for these observed petholopic responses hove been diffieolt " 'Ul" detersine cxperioentslly bec.use of the difficulties encountered in produoin, fibers of sDecific Siie dieensions. K * * 24 s i w ar; The TWA a irb o rn e a sb e sto s sample r e s u lts fo r a l l f a c i l i t i e s were * * the c u rre n t OSHA a sb e sto s stan d ard . . -- -* - b< ,, , -- - -- - lh e OSH, c e i l , n s . 4 . * . * i s ,H, H i , , , , e v e p e ,i e ^ c e , br*k' *m s ; u ; " * , -M / - - - - - aethods examined. .ecu w - -- - -- " - s,os; -- ItanS.rS fc, .be.,. > f U cf the TW, P f r , TK. vicSH standard recommends concoer.eioni exceeSict eh. r . . " " ' ,h ' ,, S-hcur TV., p . . 0 , < . > 5 ' '*" h * ~ * o.s rib.-/, * ~ cooli co, b. . . . C l Sirecely p'ria ; f,,t ~ - OSH * ' cct c .U .c e .4 ever 15-bi t " " 1*' w .r eb. . . . p i - n . c . 4 yi.1 - 4 - u . ^ t"- . i c i . c e . . f v .r i .e i o c (CV.l bo " c" '`"!' r" 1 " ` , c e h .c 0 3P ) .2 : C c c s c n e l y . <b t i U r c c c n e m i c c S .e . . aethods/work p ra c tic e s. 25 4 . \ / C0SCLIS10S , r .u; 5 ^nd other ,, m,.1 '2 studies indicate varying concentrations >e results of thi ,,oosure concentrations fiber exposure to brake echanics. The po f asbestos fib utilised and the existing re apparently affected by the wor lty# The results of this nvironaental conditions and controls at ea ^ TVA study show that S of U of the ^ ^ _ures . fiber exposures abo the SlOfH recoaaendation. le# vere analysed by . 0SHA standard, furthermore, when sa.pl vere below the d were identified as asbestos with the TEM, only 30* of the fibers ^ (jb5) or unknowns (50*). refining fibers being catego - asb,,tos concentrations (>S V" lenfth)'4S detC H ever this does not preclude the pessitilit> \ reported (see Table d ^ ^ c o n c e n t r a t io n 5 w*en all fiber s i , ranges cf higher airborne as - ^ ^ analysisi n t h i ^ ^ % .. ccoonnssiiddeerreedd.. AAss ddeetteenre.l"-----.-.-.-.-.-................ ,Ti rWT T l OoCf osVhorsthort ---- ther reported studies,---- fcU :) and research ------------ --- -------------- -- T cth) j r e u s u a l l y present (see T a t i e ^ ------- ------ ibers (<5 lcn6th> * - - - ------- v exists f ^ T a s b ^ s t o s i i b e r s r------------- 7"ltllT . potential Stealth risk exists--------------------- > his indicated that ....... ^ ^ T T f c r the unknown "" ------ r .,.a , potential health risk ^ ------------------ | 5|UU,B iinn lleennggtthh.. AAl^soj,--,----------- -- of ani*al ssttuuddiieess imn which k v--- portion (^SO^) of brake- US * 22,23,21.5 concluded that 1-- . I * " (is*iPteU "d'i".ei nsions) an-, to ,, w.i-1 -+ * > " ,, eh.r.cri,.U, o' * *r d , t r . . . O ' " 1 - lucing a biological effect. n. .. ......... . * " "*' 26 >t. S P " d*' y ,, . h,, k, j.k , p.rfnrwi - w - * - * ' * : ; ; ; ; : ; ; ir t ,, .u - p,, ,.kk .hi). W (0,, , 4 Pr.k. .cs surveyedj. TThwee eexpposures to *echanics d >uch -f^antlv hither than the exposures for those wh r e not M i n i f y . W B (<3 . inutes) peak expo- U ,, brake servicing. Conterse >, t e # ff of b rakin6 asse . in this studv during the dust clean ,ures encountere ^ used. All of the cleaning blies were offtt#enn hhiiggher when compressed concentrations a c e r t for vacuum cleaning, had peak iioe M thods sur>e>e , ^ ^ . ,, c ^ e n d e d ceiling exposure level of *" : ,r; ...r.... - - -- -- - ~ 0' 5 fl1' " ,, 4 .,,d in . ....... . 'h' ^ w `hich " prT ' o ; . * ,, . -- ,h>i ,,P4.uk. Ii. * of iirb0,, t ,, p p . U k . ,4 ........ * -- ..4k . k U . . *' * " - ,h, V,, ,, U . .l..`PP '- i,,C th. cl.*". ' br*k ' ods are properly utilised. . .w.t wfrc within* tftAls had concentrations TM " U '"'a " 6u, On. . k ...P*' * OSH. .nd S.CSH . ^ ^ c[ ^ coll..d .. f.d.l. B " * ,, , , , d . d . OSH. t.nd.kd of j 4, 1 4 . 111. H O S H k.conk...; - 27 RECOOlESCATIOSS 4>,, f r ,, .* ^ _s r n -- s c - s a S T n . . ! . H *IiU ^ = 1 " - * f ^ r. >U0. ,H. ..T T H S T ^ T * " T ^ r r ^ n , *. >., -- - * - - - - " i-por,*n' * " ; for ..X ,, p u r . in . . m s of tiol.sio.l ' TM r . * * P*"" ,, P.,ur, X. .ueH hi,nor ..0...O. f i * r o.no.n.r.oi.n. for f"' " Sinee there is no knew, safe asbestosjiber exposure e , y .... 4..^TrgmT~stud.v or ^ S S ^ jr - c . - k c r s --------------- -- flf w a v abnormalities consistent with 1^ 0.1 ....no, P-- Th,r : : r i ; " , ,, . b, . ,, ,, i n s , -- - " * " `* " " " ' . * "^ "i" `- w "prs* " v*cu: ,o -- o n - iron Ore*. -- - -- ; ; ; ;,,, blov-off of brake dust by .pressed air .ust be U . m . t e d . To ur protect the health of the brake ^chanics, a personal r M *l""r> * lien ?ro5ra. ahould be initiated. This - -- " * _ approved respirator, for asbestos, a proSra. for proper fsttinS P resrirator cleanins and the replacing of fi tin. ntenenee pro.r.. for ro.f.roi.r The pe.h .. TV* expoiore dee. indie.ee. *' - * * * " ,, o, ,. ...r re.pir.eor* U . p e r f . * * * M r r for ech.n.c. v-hiculor neehan- In order .. 28 . , ,,,, Cluh MO pr.par.1 " . > titlPe"d "Reconaen,,ded, rr.-eocceeaduurres tor < "d C1"" h S m i ` i ` ' .. P . to . u t iliz e d during these types of work usks. (see Appendix C) to u t m - e 29 appendix a references (May-June 1979)* 2 Katinnal Occupational *-irl Surv,y. . EES; " , Stanford ...arch . . a i m . 11976). C6..1..1 712.1000C, October 19/7- 4 . 0=6 of .a h i . t o r u . 1 S f o m m h ' ; $ g mional wril ,,!l- ? . Molded Materials Co., Ridgway, * H*rri'* k*,n,r' 5 . Keasbev and Mattisen products catalog, 19-0- A*b l e r P 6 Friction Materials on Automobile Drakes. Fleet Owner, (August 1 9 C Carroll, W.C. The Manufacture of Brake Linings. British Plastics 414-417 (August 190.). S. Anderson, A.E.. and R. Coaler. Ford Motor C o . , Detroit, Ml. unpublished notes. 9- ^ ^ t ^ l t a i i ^ l l ^ i - v e i ' : K C haFter 11, 4 o > 4 7 2 . (19ot). d^ H . 7 ^ . N-- 1 , . . . . . .i- curihc Brake u "`t , t , ... ... - V i T r 1K S U S i "S S a f ' s ^ i ' a n d Sal. Staadard.i vtPSH Manual of Analytical Methods. 2nd Editio , l 2 `J i l l S * ! H o i 12 #. 39. Publication, No. 77-157-*. <"> K0- " B iti,, , n o - 7 1 NIOSH Manual of Analytical Method,. 2nd M i t i o . " 2 . * * * * + - 2ndEditien> D C (1977). N10SH Manual of * j" ... ............... .. 16. Kevhouse, M.*l. and Thompson, H. Mesothelioma of Pleura and Peritoneum Following Exposure to Asbestos in the London Area. Brit. J. Ind. Med. 22:261-269, 19*5- 17. McDonald, A.D. et al. Epidemiology of Primary Mal.^nant Msothlial ^iMKrt j,n Canada. Cancer 20:914-19, 1970. 18. Greenberg. M. and Lloyd Davies, T.A. Mesothelioma Register 1967-1965 Brit. J. Ind. Med. 31:91-104, 1974- 19. Bader, M.E., Bader, R.A., Teirstein, A.S., Miller, A. and Selikoff l.J. Pulon*ry Function xnd Radiographic Changes in 5 Workers with Yaryinc Duration of Exposure to Asbestos, Mount Sinai J. of Med. 35:492-500, 1970. 20. Davis, J.M.S., and Coniam, S.V. Experimental Studies on the Effects of Heated Chrvsotile Asbestos and Automobile Brake Lining Dust Injected into the Body'Cavities of Rice, Experimental and Molecular Pathology, Volume 19, pp* 339-355 U973J* 21. Koshi, K., Hayashi, H., and Sakabe, H. Biological and Studies on Serpentine Minerals in Heat Treated State, lnd. Health, Volume 7, FP- 6o-?5 (lp9)* *'' Pott F. Huth. F., and Friedricks, K.H. Tumorigenic Effect of Fibrous Pust'in Experimental Animalsv Environmental Health Perspectives, Volume 9, PF- 313-313 U974). 23 Pott F., Huth. F., and Friedricks, K.H. Tumorigenic Effect of Fibrous `Experiments Concerning the Carcinocenic Effe" of Fibrous Interpretation of Results Considering the Ca. .nogenesis m Humans. Annales d'Anatomie Pathologique, P a n s U97o), Volume .1, pp. '4. Davis, ...M.C. The Fibrogenic Effects of Mineral Dusts Injected into the Pleural Cavity of Mice, Br u s h Journal Exp. Pathology , Volume S3, FF- 190-201, (19721 , - r .... u r Lavard. M., Tegeris, A., Miller, E., May, M., and 2,. Santn, M.F-. t |f Fibrcus class: Pleural Response in the*Rnt in Relation io Fiber Dimension. J. Katl. Cancer Institute 55:557-603, (March 19771- 2. U.S. Code mf Federal Regulations, Title 29, P*rt 1910, Section 1910.1001. July, 1970. o- t-idil s a Bayer, S.G., Zumvalde, R.D., and Busch, K.A. K10SH 2/* Technical Report ISPHS'MOSH Membrane Filter Method for Evaluating .SHio, fiber*". M B (KIOSK) ,.bli=..iTM s.. 7*-U7. February 1979- A-2 1 * s ; ' i s a c ^ S f a g g F *4 * u- : ' - 29 . H l , J . . . < , >.*.. U *< " . * ; * ; H ir Kock Ysorrk ^Acad-emyf cof.WScience' -s. I2/f1:H330-344w. *9/0. 1- " th K" 1969 S s ^ s s r s t s s s r - s a c & a ^ S S S a F * 1^ X A-3 appendix b Description of Facilities Surveyed Facility A H,jer services . F.ciUty A. . . * 1 1 . br.k, service * P . c " * ef front-enJ .lip-.- * * * * ' s.rvici, ,be creel work verb <* "P ' " 4*S`" 4 " " ^ Facility B recili.v B res .he lerces, ef 0 " r' ' ' " 4 ' Other services prciBei by f F -- **-- sb.erb,r refLcc.c, cr rep.tr. The five fU-t... h e * - k e A free peer s e rve, steils. , hours per bsy. b - > P - * '*" operations consisted of 35 to 45 jobs per week. Facility C ,, Fecility C, . .unieip.1 A . " J" ' P" .ere perf.r..B . - 1 trucks. Brsk. - i " " P " " TM 4 W Bf.xhe 60 sutb -chseics. the hour, ef opersti. re 6 k.ur. P * .4*>- 5 days per week. B-l Facility D H . * "r*s" ....... . " . -f cars or light trucks. There were r vehicles consisting ox j v . ,h, f.cilitv prrat.b 8 tour. Pr *> .poMibl. for br.k. *"d ,h* ' . 5 days per week. Facility E , paraee emplovei three mechanics that r.-iiitv E a municipal service garage, eF . ; , p" : - =-- -- . . - d * ....... -- - - - vti"on'i4ng. The brake collection, Adumprs ani V U . e^ rtT licht Ugn . -- -- trucks, autos, and seme 2 ib KbMjrs .,r dab. 5 days per --3-.heeled week. Facility r . /i Facility F, a private and light truck mainte.-n. rvice cf iinneer* Fpecrformed complete autvr.'.ti shifts, 5 days The shop normally operated two shut., a . About pr week, and there were usually four full-time mechanics F __ ..... week. Pr shift was performed. B-2 APPENDIX C RECOXMESPED PROCEDURES FOR ASBESTOS BRAKE AND CLUTCH SERVICING The National Institute for Occupational Safety and Health (NIOSH) has con ducted research on dust exposures vhich are generated during brake and clutch servicing. Based on data denonstrating the potential for significant asbestos exposures during brake and clutch servicing, NIOSH has investi gated various w;.rk practices which are utilised in reducing asbestos expo sures. These investigations have indicated vacuum cleaning systems to be the most effective method for minimising asbestos dust exposures durint brake and clutch servicing.1 Vacuum cleaner testing have demonstrated these units operate reliably within design specifications. Tnerefcre, NIOSH recommends vacuum cleaning as the primary method to be used for clean ing of asbestos dust during brake and clutch servicing operations. The following are additional procedures recommended by NIOSH to minimice abostos dust exposures: 1. Where possible, an area shall be designated for brake and clutch re pairs and servicing. Entrances into this area shall be posted with the following asbestos exposure warning sign printed in letters of suffi\ cient "sice and contrast to be readily visible and legible: Asbestos Dust Hazard Avoid Breathing Dust Near Assigned Protective Equipment C-l Do Not Remain in Area Unless lour Work Requires It Breathing Asbestos Dust May Be Haiardous to Your Health 2. 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 particulate air filter system (HIPA-greater than oot efficiency for 0.3 > diameter aerosols). After vacuum cleaning, any remaining dust shall be removed using a water dam pened cloth or rag. Under no circumstances shall compressed ; ir or a dry brush be used for cleaning. If vacuum cleaning equipment is not available the wet bru: 1- cleaning method may be used until a vacuum cleaning system is obtained. Where wet brushing is necessary for clean ing, a SIOSH c e r t i f i e d 'respirator approved for asbestos shall be worn. 3. During brake pad grinding, riveting, and punching operations local ex haust ventilation and dust collection systems shall be designed, in stalled, and maintained in accordance with the American National Stand ard Fundamentals Governing the Design and Operation of Local Exhaust Systems, ANSI =9.2 - 977 to meet the asbestos airborne exposure stand ard. . 4. During clutch servicing, a N10SH certified respirator approved for as ' -feestos shall be worn during the removal and cleann.g of the clutch, pressure plate and housing assembly, and during installation of the new lutch assembly. Whenever possible, cleaning shall be performed with an HEPA vacuum system as described in (2) above. C-2  . hrikes and clutches are 5. All table and floor cleaning in areas where brakes repaired eheli be den. ui.h the "Pi c u e . ' 1 " " ** 4"C" b'4 " (2) above. Crindinj and rivetint chines shall also be cleaned with .,,ch a Cleaner and he r.aainin, dose uiped I * a 4"'"'4 d oth. i K 1 M H certified respirator approved for asbestos she during this cleaning. __ 6 If no, in effect. respirator propra. shall be established in accord ance .ith the Occupational S.fe.p and Health Ad.ini.tr.t.on (OSHA) Standard, Title . 1910.13d. , - HEPt vacuun cleaner f i l t e r , cent.inins asbestos dust, cloths or brushes used for uipins br.h, - 1 * " 4 *" , brushing shall be disposed of in accordance vt.h b.S. Ent.rennen. protectaon Ap.ncp W A) repulations. The,. r.eul..iens state that the asbestos vast, shall be disposed of in ...led 1 * -- " " ` ,r containers at a disposal sit. shich . i s EP disposal. Also, the vast, container, s . l . displ.f the > * . -- in letters of sufficient site and contrast ing label or tag prxnted xn letters ox to be visible and legible: CAVT10S ' - Contains Asbestos Fibers Avoid Breathing bust . ,, . thin, ..be.... bust Her Cause S.r.ou. W > -- ithpTtos waste disposal are detailed xn The EPA regulations for proper T i.lv 41, I TM . f * rt S"kp* r' * * " 4 * ' 03 . fr asbestos shall be worn during 8. A NIOSH certified respirator approse r ,, o , . l of c m U C kick d"S' ' 9. f 4 "4 b" , ' r" " , '" U - . - - 4" 9. . , p . ,, ,, fro . * . -- -- - " gainst asbestos dust contamination. - ^ " " rl" `U*1 ` u i . -- ot 9. r, .kick c t c S * OSH. C . U i n , 1.V.S, * * ine . , ,, a 29, cm, nrt -- -- -- - 1910.1001 IP) h . n * f n ' 4 - " d" `U 'J " T " U . 1079 states: the 6-hour tin.-'Ciikt- Th. OSHA Ask.cTM AtandarS > _of---- ------ . ... ,, id *Fl ' i.neth , WH ..rS .ro . c.nccnfrtci.n. * * " * " tib' " " ^ ' ' . l . f ticrcPif ,, p o ,, S . h . U H.< . i 2 < * " ,b l S * . (fibers >5 u b 'c c K The ceiling air- rer cubic centimeter of air (fibers 5 10 fibers >5 v/cc- ' , . r r;v,Pc >e vm'cc with a permis- OSH in 1975 prop. * 4 *" 6- |,"ur n t ' tible cei.l..ing exposure ooif sS fiber* >S '= <' W > *"'d m i nu t e s . NMIOOSSHH ccuurrrreenntly. recommends that the TWA exposur .,, ,, S in t ' .bestos fer ,, o . , f i k ............. ....... * * 4 any l5-*inute sampling P*"14 * ** ' S 4 HOTE: Strict adherence to the above procedure. should t0 .,,loy.e during br.V. .nd cloth .vicing. Th... r.co^.nd.tion. .r. b..,d on th. result, of re.e.rch conducted by H10SH. Prepared Bys Division Nat , ,, . 1 -- .................... r`,,d In.titute I.r H"U h Cincinnati, Ohio % C-5