Document 37kzkqmQM9Q85qM9wpEQYY76D

v aia/7/SA?c ^ ^ astcotos Mm ktau)?. ik ms friction irgnasr The Problem " - Exposure to asher-toe dust is recognised ee a potential occupational ha nerd. i- Aponr work people exposed to high concentrations of respirable aubestus ~ dust, (such as Is known to have occurred `.'afore present day dust control r-easures anc work procedures vere introduced) casoc of cancer and * arbesiOFls fcave*been reported throu^out the world. * The difficulty of reliably identifying the occupational history of those whore health h^s bten effected r.ny yeere efter has resulted in any contact with asbertos be ins regarded vith caution and all neteriels containing asbestos ** . .-haing attached indiscriminately. . Since friction material is widely recognised as one of the products for vMnh asbestos is rn important ingredient* it has attracted such attention. . Indeed, the asbestos industry, in reminding everyone of the vital role . plcyad by asbestos in brake linings, has stimulated such attention. "e'rerthclcss the occnpational health record of the asbestos fricx_on ^atf-rlal industry is good and only a few cases of asbestos-related disease . fvc on record, h'ovevcr, the widespread use of friction-mi.eria.1 inwall type of vehicles has raised the question of potential pollution of the environment ` vith am assumed consequent danger to the health of the general public. 7I*r friction material industry, therefore, hat two basic problems. The j ' -, the occuprtional health problem, has in many areas bt-er. resolved, Uc-wevor, the industry must continue to ensure that those employed in the y'lrufacture of these roterisls ere not exposed to oust levels which are h-'-mfel. An extension -f this problem is the need to an -re that workers crplryed in the subsequent use o; friction naterielp, ei.ner in the fitting of the products or the maintenance of vehicles, are not exposed xo I c The other problem for the Industry* that of possible environmental pollution* is more difficult to resolve* based as It Is on emotional anxieties (vhich are in no vay Justified by the evidence). A climate of concern for the effect on the environment of expanding tovra end industries has led to the notor vehicle being included as a significant factor in this pollution. . ' This feet together with the publicity given to asbestOB and Its classification as a carcinogen ^ have all combined to lead people to question the use of asbestos-based componente In motor vehicles. - The automotive Industry is also under attack for a number of other reasons, (e.g. pollution* vaste of resources and congestion) and vould gladly be vithout the esbestos problem although it mast accept that for some years* . current models of motor cars vill need , asbestos-containing materiel for , _ C replacements. The friction material Industry Itself must therefore dispel ' * anxieties about asbestos-containing products in motor vehicles by ensuring ` that the existing reassuring evidence is "made manifest and Is properly understood. ~ . Tackling the Problem * ** ...In order to tackle the problem most effectively* it is important that the ` - origins, investigations and remedial measures involved should be veil understood. This is especially necessary since the existence of the friction material environmental problem is to a large extent based on confusing tuo very different phenomena; on the one hand the occupational health - experience and dust exposure data related to manufacture (and the subsequent fitting and servicing operations sometimes called "para-occupational") . and oh the other hand an assumed emission of similar dust into the general . environment as a result of the daily.!vearipg dovn of brake linings and . clutch facings. - An example of this confusion may be seen in the evidence given to the UK Asbestos Advisory Committee* vhere olalms that the general public are at riek are supported solely by reference to a survey of motor vehicle maintenance vorkers.^ * ---------- ------------------- XT' ' -- These facts will be reviewed under three headings, the first two covering the Occupational areas of Manufacturing.and Servicing, and the third , * heading covering that of the General Environment. . Manufacture of Friction Materials ,. There is ample evidence to suggest that, in the manufacture of friction materials, the concentration of asbestos dust compares favourably with * . .' that found in most other modern asbestos operations. Within the last ten years efforts to observe a 2 f/ml* standard have led to further imp rove men ts in dust control and there are now many operations where levels well below this maximum allowable concentration are achieved^. . Very' few cases of asbestos~related disease arising from friction materials' manufacture have been reported. In evidence presented to the UK Advisory Committee,^ Ferodo limited, who have been using asbestos in brake and clutch linings since 1910, reported 8 cases of mesothelioma and 5 cases of asbestosis. The mesothelioma . * cases had all been exposed in the manufacture of railway brake blocks between 1928 and 1933 or during the war years up to 1943, to crocidolite as well as to the chrysotile asbestos more generally used throughout the plant. The asbestosis cases'were all involved in mixing processes where masks sh6ul3"have "been worn. ** . In the same volume of'evidence, a report from the two Cape Industries1 factories manufacturing both textiles and friction material (one since 1901 and the other since 1923) cites 9 cases of asbestosis and no case of mesothelioma. - __ Ferodo report that "many millions of man hours have been worked on finishing operations of ashestos-hased materials; though the dust concentrations . associated with these were at one time very high, there - * f/ol (asbestos) fibres per cillitre I -4- has not been a single diagnosis of asbestosis as a result of this . Closure". In core recent years (1968 - 1976) however, averse concentrations vere veil below 2 f/ml following continuous Improvements in dust extraction methods. . ;t - * 9 An investigation in 1975 by Heidernanns, Kulinen, Schutz and Froehpska into dust hazards which might he associated with the Manufacture and use of PFhcstos-contf. ning friction naterials (updated in the ?erearch ?e.port of the German T-eruffigenosscnechaften7 cxiotes concentrations of riicro-dust in the range of 0.09 to 0.20 nig/a during grinding, drilling, saving, turning and milling operations (the current IKK* value is _ 0.10 Ti*/*? or 2 on this basis the current range is 1.8 f/al to A f/~l), on average just below or just above O.IJ or 5'f/cl. Fuch operations, xml ess subject to dust control, vill erit duet containing asbestos. A number of surveys of such operations hve been carried out in Gemany 7*9* ITi VSA 15t14*.15l6,17 ard elsVuere 558 na it is clear that, under some conditions of working and where cuch operations ere carried out continuously, duet concentrations above 2 f/nl (or the of 0.10 mg/m-') can ba reached. There is some evidence of effects on health prong rn engaged for a long period on such work. I.'edicel end epidemiological investlg.f.tions by Professor Voitovjtz, Valentin and others 1 on workers who rad been continuously exposed for at least 10 and up to 25 years to asbestos dust suggests a similar risk level for nen employed on finishing operations (t -'uly g-irdirg and drilling) in the automotive industry,to the risk .. 79 level of ;rr*:*rs in the Manufacturing industry . + - .........-- * It vts noted that the automotive industry group studied had had long Q* e.>~.*osurft from a very early age. ^ A group of men carrying out brake. * Ifil = Technical Control limit .+ Out of $A workers (including 45 women) in mEnufsct-jrin^, there vere 3 probable cases of ssbestosis-and 11 possible"* Atong 3 06X1 employed. *#i - .- in finishing operations on brake llnincn in the automotive indeed i-v-. 2 probable eebestosia cases vere found aid 10 **!<>*sible". (uPawJvx<a -5- maintenance services vith exposure primarily during the cleaning and brushing out of brake drum dust gave little evidence of irihalAtion effects in spite of long years of exposure. .. , Professor Selikoff's investigations ^ quoted indications of abnormalities in 32 out of 87 motor vehicle mechanics (0 out of 29 vith five or more ~ . years intermittent exposure shoved signs on X-ray of changes consistent .* vith asbestosis). Another report of the same investigation quoted 2456- of 95 brake service mechanics shoving chest abnormalities not necessarily asbestos-related and it is emphasised that there vere no confirmed cases of asbestos-related disease. Dust levels quoted in connection vith. this investigation (in USA) ' * refer to mean concentrations for blow-out' ` * of brake drums, grinding of used linings and bevelling of nev linings of 15.9. 3.8, and 37.3 f/ml respectively - much higher than'any'found by any * - other researchers. 37o information is provided as to the duration of these samples -- they are frequently referred to as peak concentrations or the mean of a number of such measurements. It la also clear that In the . case of bloving out of brake drums, no asbestos fibres vere visible by optical microscopy; some chrysotile vas identified by X-ray diffraction. Fibres identified by electron microscopy vere all below the minimum size specified in the definition of asbestos fibre (i.e. 5 in length) . It should be noted that the methods of sampling and the .criteria for measurement of occupational .environments Aid not -conform to the .methods used by .. governmental agencies and by other investigators in Germany and OX. Per comparison, concentrations of asbestos dust during brake maintenance . reported by Hickish and Knight ^ shoved an average daily exposure of 0.6S f/ml (range 0.21 to 1.12) during brake service of 11 cars. During . truck brake service, the average vas 1;75 f/nl vith peak; during cleaning . . of the brake drum, of 7*09 f/ml. *V _ The German investigation in 1975 ^ (now incorporated in the Berufegenossenschaften report ^) recorded high concentrations* in the brake service department and * 0.03 to 0.79 and vih background workshop atmosphere of O.OJ to C.05" I where r nchin*ng wps done without dust extraction. Althou^i high concentrations of fiur.t \-cre observed during bloving out, no chrr-sotile asbestos could be detested by infra-red spectrometry, end-the individual - fibres which could be detected optically could not be identified es - asbestos. - - - ...... - - The General Tnviron* r-nt bvir-ng the application of drum brakes, disc pads or clutch fac fr.gc, .. f;.11 quant it' eo of the sarfece of the friction rater* si are vo*n e.vey. Those jsaterials contain between 30- to 60S* of nsbestos, and it has bc-ea as Pur'Sd by cons that thereby large quantities of dangerouF asbestos dust are being regularly discharged into the atmosphere. This, tt is argued, creates a dangerous atmosphere a':in to that which has produced esbectoc- related disease (especially cancer) in cone voriring environments. Since the estimated consumption of esbestos in friction rjaterial is annually over ^0,000 tons 22 *for Europe and oyer 50*000 toss in the USA the anoints involved >zo substantial. An salinate carried out by the F-endix Corporation with the support of the US Environmentel Protection Agency (liTA) calculated that the amount of friction materiel worn svay in brskes end clutches annually in the USA is around 60,000 tons, (of vMch 37,000 tons is the asbestos content i.e. 60;.'. In Europe the content of brahe linings is nearer 30!). However it is clear from measurements n?de at a numVor of locations with heavy road traffic that insignificant quantities of ''espirable asbestos dust are so emitted. * . the first ir-gorif-nt' focn^r in dispelling anxiety is that the asbestos content of the wear products of friction material is not enitted into the atmosphere in the for.- of respirable esbostos dust. Indeed, a number of ambient air investigations indicate that it,is difficult nowadays to find asbestos fibres, in any significant quantity, regardless of size, in the atnosphere - even in the vicinity of asbestos nanufacturing plants,2^ lucPBsrremente of the aribient^eir even In heavy traffic conditions to show any significant level of asbestos. Again* in wndei^rounA rr n**rg -7- confined tunnel environment might be thought to create the vorat conditions, no significant build-up of asbestos du3t has been detec*ted.,24 *^25*2. 6 * She explanation Is simple end is confirmed by a number of careful scientific investigations. The heat generated in the process of applying1 the brakes or the clutch (the reason in fact vhiy asbestos is such a vital': component) is sufficient to destroy the original structure of the asbestos fibre. From-a temperature of 450C the chryaotile structure begins to convert to a non-crystalline amorphous phase, leading to a loss of stability.of the fibre structure. The median!cel strain applied during the braking process has a pulverising end grinding effect, leading to . 7 disintegration of the fibre structure. The Genian report calls it wa kind of micro-milling 00 that the dust no longer contains eny fibres". .* * . ** _ From a tenperature of 6^0C a new crystalline structure develops called Forsterite, which will be fully developed at temperatures of above 7OQC. Generally, forsterite cannot be traced in brake lining dusts. This means . to .* - _ ** * " r that temperatures beyond 650 C either do not occur or are only very short lived. The decrease of the chrysotile content, however', indicates that temperatures beyond 45C are reached because the amorphous phase of the chrysotile cannot be traced analytically (by either infra red-spectrocetrie or X-ray diffratcmatic methods). ** Examination of the residue of wear products in brake drums confirms that 27 the asbestos content is usually less than 19o of the residue. It has been suggested that the dust escaping into ambient air may contain a higher .. - proportion of the fine respirable asbestos than dust left in the drums but careful studies designed to entrap this escaping portion of the wear # . product show that this is not so. Various Investigations into the amount of .asbestos remaining in the residues from friction processes have been carried ' *. out which Indicate how minute is the fraction of asbeBtos released in the application of - friction. She latest report, 7 from Germany, con` firms thet technical investigations in recent years have repeatedly shown that the dust generated by frlotloa of the linings: in use -- as opposed to dust created .O J 8- - * s ' . ' ' "!~r : during the finishing and handling pt new linings -- as a rule contains only traces of free chrysotile fibre, i.e. of the order of 1$>, She . .. . working party was unable to provide clearer infra-red spectregraph!cal evidence of chiysotile, Under phase-contrast and electror.-nicroscopic scrutiny, the dust contained Just a few isolated fibres which could act even be definitely identified as asbestos* This is consistent with the investigation by UX eovemoent and industry investigations'in 19<>9 which reported that the free asbestos content of wear products of drum brake linings rarely exceeded 1?5. {in disc brakes the content was even lover.) . The I-endix'investigations Tor !HOSH in USA in 1975 gave a range from 1 * C$r/: to 0,00355 -- only three tests were above 1/5 and the overall average was 0.23;. This study also determined that only J.2J5 of the asbestos content of all the wear products over the whole range of US motor vehicles became airborne - estimated at 5060 lbs. annually. ^ -' . . *' '' The* 7ord Kotor Company carried o ut a study 28 based on dynamometer tests which shoved that during brake usage less than 0.01$' of the lining wear vac released in the form of free asbestos. The study estimated that concentrations of asbestos fibre in the urban atmosphere in the US due to brake usage was less than 0,07 x 10*"^ (.07 nanograas) (less than one millionth of the 2 f/ml occupational control standard). JTe-.sure^ents carried out at points of heavy traffic concentrations in- the UK by the Aebestosis Bescarch Council, under the observation of the TUC Centenary Institute of Occupational Health,- also found Ho greater concentration. Sven in the underground 'railway system, this survey found the asbestos content to be of the order 10*" &/isr to 10~* to 100 ngs/m5)24 '. (10 ngs - * Tlnally, some observations made within tbs last three years by two occupational health experts, on occupational risks and risks to tha I . --- *4 s w . T* -- -9- pa ' Tr. John C-ilson, *'reviewing rubcolos no'nn occupational hazard in a gfnc-rel croup in vihich he includes friction natcrials, cays "Ik?spite the thousands of products .containing asbestos, evidence of ill effects froa their use is very p:aliM. He adds the qualification that occupations . Involving brahe shoe so.inicnance heve been sbovn to be at rich in the past, ''Although nost of the asbestos in brake shoes is degraded, the duet in the- brake druris st^ll contains a snail percentage of asbestos". "The ragnitude of the risk (of eele&tosis and ssesothelio-Te in there vorVins regularly in this employ:.ent) is r.ot known but is likely to be sr^H." Professor rji'lhui*r, 22.' in his report on public health risks, concludes "There is ' evidence c-f no excess ansk of nesotheliorra from asbestos pollution vhich :i:<s exlr-ted in the li^i/^bourhood of chrysotile and arosite nines. There is ^nc .evidence of a-risk to the- general public at present". Later he repeats ik's viev in hir. general conclusion "There is no established evidence that, true e-ftrent exposure, as prevalent in Vcsicm Z^iropeen cc-.mtri es, at -th-is moment c?.Triec such a definite risk; however, there exist too nsny v.r.cc-rte'ritics to deny such- P. .rir>, though if the rie': vas substantial it is likely it vonId h^vc been detected by now". Cr:-';LV?JC'VZ l -T. 'Ci ctuye There can be en occupational health rash in the rmufecture of asbestos- ?ed friclr.on r atarielc, However, experience hes shown th?t this is & very' 1!' ivac* ;.2~lth r'rkand that it can be effectively controlled by veil tested equipment and.Work procedures. # "trnd=rds based on e;rtc-nsive experience in the industry' have been established end equipment ic available to maintain these standards so that the occupational health risk con be controlled. In nan;' countries these . stfnc&rdc ere enforced by legislation, but in any case trade and industry have on obligation,. as with any occxtpatlonal safety problec, to lnplegcat the effective rick prevention iso e cures vhich have been developed by - 10 - In corf-'. r conditions invc-lvirij r.'f.-v'ci.iij, e^c., t/v-re rwy te p vf-.rc-- cco'ip^lir-nrl ; a*-' rn. T3'e ?j;Vri'y cf*n o:r-v?ce 5nfor-at ion to cnsnrs ... that v**:ni*3 m:'rrr--l"n!1 vfl'ie;* it c*rcu. elrnccs mc!i rlcVe opn price end low tU;- cm evclitpa.30*31*32*33* 1**1 ^ ^v"{ * TV. **."Irr.r ;? 'nc'cr-te t'.f t iha v *'' "-F '. c .''TV-.':'.' to t*ll th-?~ BO. 7 > 1 * < nr ?'z'-~ *nd I t- j l? *.7V 1&=1 to f* c 2. c C. V C e. . f /JT* v-vy*r jv f"-r v-jx '*/j * y7^*7*^C??l\T **% ^^- ;i.r.:i Vnlihrr, JT. , (fcy *' y) ~`rc>j;r<t'..`>."Jrn;F n;.**`-r*.'.l.' Vni*-, p.'.rmTh, ''^!*p. ,lZr>t;'Jf- Pro'llC:r~ !: the IT.-;5 of AsTcst.os ry^'cts". Proceedings of the International Conference on Pneumoconiosis Johannesburg, S.Africa. 1969 . ~k-ic.rr-2~ i, Ay-pint f.vjd ^czrA; "T*sp`*?.*Mory ^vr^v'ii.'vo;- of /Fbesioris". Lt C?l Lavoro <Z (7 - o) 2$c - ff-1 July ly??. "i-'V'-'j'"*, G.7".: Jr'lit-ic- ic *:;a ,*-2 ii-o> f, 'Joytno, !',2y. "Ic^yt:f:cation *=j:d p of AsV-s*cr C?-'"p?.t tonally 2j;po??d "# v>*oJ C/Vr *1"?* .- * ... .4 Inif-ma l-'cnl '.^cr.oy f.-.r Re search on Oivrr. I.A.E.C. J-c:v*jr,-p:>r "or IVr-l"'iir-t r. of faror-.o^anic . r.ie': of Ch,r-r#iosls to !I-in. YrO..' 1 /; AoV-cf-c. l;c:``,"?rarne. 'f77* ** `. "S"2sc;tr:' vvtii on cvice:j',*e rr.Vviitcd Sto the Advisory Cor^lttce on A short os. 1 J7^~77" rcalth inn Safety E":ocutf ve, V~. 1977* Crorr, A,A, It rector C-cr.crel, Ash: stop Association, London. "Progress in the Control of Asbestos Iwrt In .the Vorlplnce'", Ti*V^ -rt or:"*2.Ccnfe^er fE or ?:.-`iv*oc<oiicrJc, Csvacas. 7*nict'V-r If7-* - r^oE7;ar>. Fftdt-.vetton of Industrie! Acc'dent an* Safety Insurance ** Corporations Z.V. J^rafaj;-Y.rr-s^nnc\ftan (ro:-.n i'\ f^rr'^xy). fie search Report - Asbestos. ` "Inve rti^atiers into Sealth Hs -fireve through Dusts "by Brahe-Ltningo containing Asbestos*1; (Analytical. epidanJological and antral. Investigations) December 1?76* "Hygiene Standards of Airborne Asbestos Duct Concenlraiiox* for use with the Asbestos Regulations 1J>9". Dept, of D'plqysent I -- 10. .11 .12 15. r<f*<** K"ilrv-h and Schulz Tiesearah Institute of Federation of Tndu-airinl 'Trade Associations (P-emfsjenocrenec?';?fl en) Torn, Cer..-n.y), nnfl r-:*ocIir:=I'aj (Bavarian Stole, Institute for In.*u :-'rirl "-mich) "Investigations into the Hazards p-eo-^isc-d by tlvst of nEbf**io3--cont.R?n'ng 5V'ct i<~n linings'*. June 1575 Cznforanre on. rzposvre to Ashc-stc-s d-ir'ni' 'rsJre and 01 etch '!?.* nl'-V'VPr.re. Pr'-nivood, 2^:jJfr.n, !>rch 1po. ) L?e G.L: British Lsyland, Longbritge, Birmingham. "Parecviag j>.rsts from Brahe A?re:-,b!> i c ~ curing Servicing Alternative Cleaning !>thocs", b) - Fe. tc. *h.D. ., Perd. u-e, Chepe l-_er.-le-7r,1th, Derby sh5.re, Fr^er.d ^Possible Alternatives to Asbestos f.r- e Friction Msterial". ) Hhight, X.L. end HicVirh, D.F., Services, Ford of- Britain, Xrenlvood, :" - "Ir.vf-rt\?i::ons *r*te-Alterative Forr'-s of Control'for*Du$t gfreraled d';r`n the Cleanin'; of Brahe Asr-c:rbli,ee and Dr.its11. cJ) T:5c*:: nh, 7.IT., entf Bright, L.L., (as above) "Z-ypor-ure . to Asbestos dvr5ns Drabe 2I* inic-rar.ee". lr Annals of -- Cc-.cvpai.iorp.l Hygiene. Vcl.ljJ Bentley. 23.L. j Kintex, Cleckhef ton, Yorbshire, LbO.and. Personal convciimication to A. A .Cross - Asbestos Dusts - test during drum brake naintenance. Kay 1974* .Cross, A.A.: Chatman, Ihviroreentsl Control Conidtlse, ,4HC * Sipl^nd. "AFtestoE Best in Fricticn Krierirle". September 175* t. ^ JecVo, DuCharme, Somersf Bendlx Corpn. and Ziivi ronnental Protection igency, USA ''Brr.'ke and Clutch Emission during Vehicle Operation". '. Autontobile Engineering Meeting, Detroit, Michigan, USA Kay 14-10 1975. c 14. 15. C ^7. V e t And* 'vichoi.scn, L:-?\y>r: j'rvnt Sinai School of J.*c-oic;no, W.yt VSA. "Arv-Si-os XxprE'.'rc- cv-r-n" ?fc.vfcc Lining l:n'rtit*;v;nce end SopP-ir". Arcerlcen Ir.dvc Ir'ol Vy.pt cne Co':-fe:.-;75 oe, T'Jp^l, VSA- (4bsirct ?<*) T-&y 1974. -. r>chr*lc_*n, !!wmt School of l>-dic"0* K*Y. U2JL. Vi'vVss'*.os Hvyurrra <iur*i:. 7>-e\c- Lin'::* K?inicn~.nts end Sf.'j-p? rM - Jn::e 1?75. (LoYV.vod *0 V* full v< rr>on of aVsirf-S- **'r.fshove - 14) Lohl, Iff snn Veira*r.ar.: Kr-'nt 3*rni School of . 7*r.rtio5net *T, VSA- ,!Arhc-etop Hxpcsvre f*r*np ?re!<e Li nine I!irVv 'r:ir*.;-:0 end Jiopa ^r".. Zhvfrc*m?rito4l ?.c tc-f-rch 12,-410 - 122 (l9?Cy. Sm-N 1?75.' LohlV Lr-i^er. rsl ir sat id's, SelSVoff : alount Sinai School.. of I'.-f 'c 'nrr, * ~V**s' c VSA.'AsLosi^f Gor.ieni cf Last ^cowiter4s,o in md repair1'. Proa. r.cyel Coc- Kef.; 70:J2-57 I * <# | | T.,^ * *.T . y.:^*r., 7.K.S Sverdlovsk Instil*.*- cf L*x*;ir, -i?n5 -;y- s*-Ae1.LTcr, VSSK. v*:\z':ns end vrevcr.*it{'cn .e?.s'*res aprinsi; Lw*-c rpr-ful +0 "eelth cf Vcr'-rfrre". (Chapter V). 1?75 J.r.? r*-:*:r-*--5-M n' si-?:*, Cr'CAci'cv*, V3A. Ter^-sal w; = ef rcrviee !-*-?/.-"'os in Tioc*:..., o.-,i ?:vt-j f*-:?., Cr.^ifcir.i:- - r.Z.c.7.". r-nC r-ciSVoff. .Asjcs* 15*75. * ` * Loririor end ?xhl; I-Tount Sinai School of Ke5ic?nc, ?jy# VSA. "Anl-estcs Lrpcpnre of Xrr.kc Repair Yorkers In th? VS". Intemet'ocal Conference on Occupation?! Health Xripkten, rrp1esber 1S75- O -4- 21, ric' "''iCin'-i Zrtiool of I Tv* tc* no, T", l'*-1.. . 'Crv yn;v`*iiv<~ l"orta7i tv t'm".e of T",:;;<? Co; orta of Vorhcrs. onnl Conference on Ccoupet*oval ricpHh, Too Iter. Pf>. - . ,' i. *.% lielrviis, Prof. H.L.: Coronel irb*Ti:etcy, TV, Iv*-re* ty nf j'i-.ste-rSa:'!, JTether\!f:i',s. 'ToMic. r'i3?.v. of .Tvj-svi"-t:o .rbcstos".' ?-p:.rt of a '.'or Group of !>.-*r-f pvsT^r;c for '-hr Co-mission of the- Z>v.'Op\?n Crevr-ntilr-F., "* r5- :-* T-rr-ie - C*:.*e-r*l for Social Affo rr, Fe&ltb s& srfe*;% '<577. ScV- stien, lijn-n and Donn^rd; Centre c.e Fcrff cticrrior-r.nt Tcc.i.nion*, K*r::. "La Follut'on At':icsp';eric'-e WrftlrrSr p=r I'Ascec-fF", Journoas d'Etude svr la ToricMo.if 7:.'-' !r:'V!=,' Feris. J:e 157.?. .- - ,21 .'fiber ioais research Council,`T'Ochoal?, Infl'-nd. Personal _ coirjnunication to A.A.Cross* "Investigation into levels of airborne asbestos dust in the London Underground, etc.". 1576. 25, Johns-TTanvillr; Denver,. Colore do, USA. Tostor. Tvbvay - Cct:^ '"rake Lining Emission 1577. ' . .2 Vinton Laboratories, Surrey, England. "Asbestos in the ioc^iyro'ird no cause for alarm". ' ' . ..........- 27. Tuffiev, B.L., Perofio, Chc-pel-cr.-lo-TrIth, Derby .ire, England. Personal Conr?>ihioation - Asbestos Content of *v-. Fr -drcts freo Friction Keterials. June l?^?* * 26. Anderson, Gealer, J'cCur.e, Spays; Ford Ilotor Co^p^ny, USA. "Asbestos Enissions from Brahe Dynainopeter Tests"., (Kef* as 13) 29. Gilson, J.C.; former Direotor of Kedioal Keesarch Council t^r.nnr>rnnioBiB Unit. Fenarth. BE. Personal coatualcation ^ v AZA/j/l/p?OV * ' . ACTT3T05 Aim ITTt.UlT, IK TKJ5 FRICTION mTr?Iilb irjT^THY *, .. , ,, i . ?be Problem " ZbcpOKure to asbestos dust is recognised as a potent!el occupational hazard. ;*Jcnxxr work people expoBed to high concentrations of respirable asbestos- dust, (such as is known to have occurred before present day dust control r-easures one work procedures vere introduced) cases of cancer and epbesloeis have been reported throughout the world. * *y The difficulty of reliably identifying the occupational history of those whose health has Ken effected rwtnjy years after has-resulted in sny contact vitfc asbertoe being regarded vith caution and all materials containing asbestos * ..haing attacked indiscriminately. Since friction materiel ia widely recognised as one of the products for vMch asbestos is rn icjportent ingredient, it has attracted such attention. Inf'csd, the asbestos industry, in remind5ng everyone of the vital role plcyed by asbestos in brake linings, has stimulated such attention. ITe-'ertbeloss the occupational health record of the asbestos frict-on watc-ri?! industry is good and only .a few cases of asbestos-related disease f vc on record, k'oyevexj the widespread use of .friction-m^ierial in all types of vehicles has raised the Question of potential pollution of the environment vith an assumed consequent danger to the health of the general public. 7*.r fraction notarial industry# theroforo, hat two basic problems. The j'z~' , tlis oecupftionsl health problem, has in many ere*>s bi-r. resolved, rowsyar, the industry must continue to ensure that those employed in the rsmofacture of these mteriols ere not exposed to dust levels which ore h'-rrifcl. An extension ^f this problem is the need to or. ^re thet workers trplcyefi in the subsequent nee oi friction aateriele, ei.ner in the fitting of the products or the maintenance of vehicles, are not exposed wo homfal dust levels. . .. (j t 2- 3be other problem for the Industry, that of possible environmental pollution, is more difficult to resolve, based as it le on emotional anxieties (which are in no vay Justified by the evidence). A climate of concern for the effect on the environment of expanding towns end Industries has led to the motor vehicle being included as a significant factor In this pollution. m ' Shis fact together with the publicity given to asbestos and its classification as a carcinogen ^ have all combined to lead people to question the use of asbestos-based components in motor vehicles. The automotive Industry is also under attack for a number of other reasons, (e.g, pollution, vaste of resources and congestion) and would gladly he without the asbestos problem althou^i it must accept that for some years. replacements. The friction material industry itself must therefore dispel ' anxieties about asbestos-containing products in motor vehicles by ensuring ' that the existing reassuring evidence'is 'made manifest and is properly understood. '' ^ . Tackling the Problem * * ** In order to tackle the .problem most effectively, it is important that the \ - origins, investigations and remedial measures involved should be well understood. This is especially necessary Bines the existence of the friction material environmental problem is to a large extent based on confusing two very different phenomena; on the one hand the occupational health - experience and dust exposure data related to manufacture (and the ' subsequent fitting and servicing operations sometimes called "para-occupational") . and on the other hand an assumed emission of similar dust into the general . environment as a result of the daily.ivearipg down of brake linings and . clutch facings. - An example of this oonfusion may be seen in the evidence given to the VZ Asbestos Advisory Committee, where claims that the general public are at risk are supported solely by reference to a survey of motor vehicle maintenance workers.^ - - - 3- These facts vi 11 be reviewed under three headings, the first two covering the Occupational areas of Manufacturing.and Servicing, and the third - * ' heading covering that of the General Environment* . Manufacture of Friction Materials There is ample evidence to suggest that, in the manufacture of friction materials, the concentration of asbestos dust compares favourably with . . that found in most other modern asbestos operations. Vi thin the last ten years efforts to observe a 2 f/ral* standard have led to further improvements in dust control and there are now many operations where levels well below, this maximum allowable concentration are achieved^. Very few cases of asbestos-related disease arising from friction materials ` manufacture have been reported. G * In evidence presented to the UK Advisory Committee,** Ferodo Limited, who have been using asbestos in brake and clutch linings since 1910, reported 8 cases of mesothelioma and 5 cases of asbestosis. The mesothelioma cases had all been exposed in the manufacture of railway brake blocks between 1928 and 1933 or during the war years up to 1943, to crocidolite as well as to the chrysotile asbestos more generally used throughout the plant. The asbestosis cases veTe all involved in mixing processes where masks 6houT3 have "bean worn. ". V1 , In the same volume of'evidence, a report from the two Cape Industries1 factories manufacturing both textiles and friction material (one since 1901 and the other since 1923) cites 9 cases of asbestosis and no case of mesothelioma. __ Ferodo report that "many millions of man hours have been worked on finishing operations of asbestos--based mate rials; though the dust concentrations . - associated with these were at one time very high* there - * f/ml - (asbestos) fibre per mil litre I -4- C' has not been a single diagnosis of asbectosis as a result of this exposure". In more recent years (196B - 1976) however, averse concentrations were veil below 2 f/ml following continuous Improvements in dust extraction methods. 9 An investigation in 1975 hy Eeidernanns, Euhnen, Schutz and Frochazka into dust hazards which might be associated with the manufacture and use of asbestos-conta ning friction naterip.ls (updated in the Research report of the Geman Lervfsgenossenschaften quotes concentrations of nicro-dust in the . range of 0.09 *0 0.20 mg/m^ Aiiring grind '.r;g, drilling, rawing, turning and milling operations (the current TKST* value is _ 0.10 r.z/r? or 2 f/nl:8 on this basis the current range is 1.8 f/nl to 4 l/=l). on average just below or just above 0.15 or y'f/d. ?uch operations, unless subject to dust control, will emit duet containing asbestos. A number of surveys of 'such operations hsva been carried out in Germany T5C ?SA *15.16,17 ar elsewhere ^*'*8 ng it is clear th=t, under some conditions of working and where such operations are carried oat continuously, duet concentrations above 2 f/nl (or the TRX of 0.10 mg/c') can be reached. There is some evidence of effects on health prong ran engaged for a long period on such work. Kedical end epidemiological invfstigations by Professor Voitovits, "Valentin and others 1 on workers who rad been continuously exposed for at least 10 and up to 25 years to asbestos dnrt suggests a similar risk level for nen employed on finishing operations (-v':nly /*5rdi.rg and drilling) in the automotive industryto the risk level of 1 or*:*re Jn the m. anufacturing industry 7 9 . + - * ---- _ It vts noted that tha automotive industxy group studied had had long exposure from a very early age. A group of men esnying out brake ** . * TRil a= Technical Control Limit * Out of 9^ workers (including 45 women) in mcnufsct-Jrin^. there were 3 prsbasle cases of asbestosisand ti Asians 3 men. employed in finishing operations on brake 1 injure in the automotive industry. 2 probable esbestosis cases vere fousd. and 10 ,^posBib4*,,. maintenance services vith exposure primarily during the cleaning and brushing out or brake drum dust gave little evidence of Inhalation effects in spite of long years of exposure. Professor Selikoff's investigations 19 quoted indications of abnormalities in 32 out of 87 motor vehicle mechanics (6 out of 29 vith five or more . years Intermittent exposure shoved signs on X-ray of changes consistent . . vith asbestosis). Another report of the same investigation quoted of 93 brake service mechanics shoving chest abnormalities not necessarily asbestos-related end it is emphasised that there vere no confirmed cases . of asbestos-rel'eted disease, bust levels quoted in connection vith this investigation (in USA) V * refer to mean concentrations* for blow-out" ` of brake drums, grinding of used linings and bevelling of new linings of 1j>.9 3.8, and 37*3 f/ml respectively - much higher than 'any found by any * other researchers. Ho information is provided as to the duration of these samples -- they are frequently referred to as peak concentrations or the mean of a number of such measurements. It is also clear that in the case of bloving out of brake drums, no asbestos fibres were visible by optical microscopy; - some chrysotile vas identified by X-ray diffraction. Fibres Identified by electron microscopy vere all' below the minimum size specified in the definition of esbestos fibre (i.e. 5 >un in length) It should be noted that the methods of sampling and the .criteria for measurement of occupational -environments -did not -conform to the .methods need .by governmental agencies and by other Investigators in Germany end TOC. Tor comparison, concentrations of asbestos dust-during brake maintenance r-eported by Eickis- h and Knight 10 s hoved an average* dally* exposure of ' 0.6S f/ml (range 0.21 to 1.12) during brake service of 11 cars. During . *" ~ . truck brake service, the average vas 1;75 f/nl vith peak; during cleaning . . of the brake drum, of 7*09 f^al. . The German investigation in 1975 ^ (nov incorporated in the Berufsgenossenschaften report ^) recorded hlh concentrations* In the brake service department and 0.03 to 0*79 and vi^h background workshop atmosphere Of -c- whore rnckin?nj vpg don* without dust extraction. Although high concentrations of Cunt vore observed during bloving out, no chr-'fiotil* eebsstos could be detected by infra-red spectrorsetry, end-the indiv.lduel * fibres which could be detected optically could not be identified es asbestos. .......* . The Central-Thy iron* ent Tyr-ng the application of flrtuiv braVoe, disc p?cc or clutch fac'r.c, .. ' f:*.&11 qup.r.i it:no of the surface of the friction rater1'si are vo-n e.vty. Ikoee ir^teriels contain betveen 5C' to 6pt* of aElectee, and it has been fiae-ured by sons that thereby large quantities of dangerous asbestos dust are being regularly discharged into the atnosphere. This, it is argued, creates a dangerous atmosphere akin to that which has produced esbectos- related disease (especially cancer) in sone working enviroauents. Since the estinated consumption of eGbestos in friction material is annually over AC*,COO tons 22 *for Europe and oyer 50,000 tons in the USA the enouate involved >rc substantial. An estinate carried out by the F-endix Corporation vith the support of the DS Hiviromentsl Protection Agency (ETA) calculated that the amount of friction arterial worn svay in brakes end clutches annually in the USA is around 60,000 tons, J (of vhlch 57*000 tons is the asbestos content i.e. 60;!. In Europe the content of brake linings is nearer 3C.') However it is clear from measurements nede at a amber of locations vith heavy road traffic that insignia cant quantities of '-espirable erbestes dust are so enitted. 2^ 2d ' " * * bke nrct ir-poriant* feotfOr in dispelling anxiety is that the asbestos * m content of the vaar products of friction isaterial is not emitted into the atmosphere in the for.* of respirable esbostos dust. Indeed, a number of ambient air investigations indicate that it, is difficult nowadays to find asbestos fibres, in any significant quantity, regardless of size, in the atnosphere - even in the vicinity of asbestos nanufacturing plants.^ Measurements of the snbien^eir even in heavy traffic conditions & int sbov any b1 gnlficant level of asbestos* Again, in underground -7- confined tunnel environment might be thou^it to create the worst conditions, no significant build-up of asbestos dust has been detec' ted. 25'?6 ` The explanation is simple and is confirmed by a number of careful . . scientific investigations. The heat generated in the process of applying the brakes or the clutch (the reason in fact why asbestos Is such a vital component) 1b sufficient to destroy the original structure of the asbestos " fibre. From-a temperature of 450C the chryeotile structure begins to - convert to a non-crystalline amorphous phase, leading to a loss of stability.of the fibre structure. Hie medianJcal strain applied during the braking process has a pulverising end grinding effect, leading to disintegration of the fibre structure. The German report calls it tta kind of micro-milling so that the dust no longer contains any fibres", *,* 4. *- *. From a temperature of 6$0 C a new crystalline structure develops called Forsterite, which will be fully developed at temperatures of above JOQC, Gene rally, foxst e*rite ca`nnot*be traced in^ *brake *lin*ing dusts. This meVans 1 that temperatures beyond 6$0C either do not occur or are only very short lived. The decrease of the chrysotile content, however, indicates that . temperatures beyond 450C are reached because the amorphous phase of the chrysotile cannot be traced analytically (by either infra red-spectrometric or X-ray diffratcnatic methods). . '* - Examination of the residue of wear products in brake drums confirms that the asbestos content is usually less than of the residue. * It haB been suggested that the dust escaping into ambient air may contain a higher t*. ... proportion of the fine respirable asbestos than dust left in the drums but . ' careful studies designed to entrap this escaping portion of the wear ( . product show that this is not so. Various investigations into the amount of ..asbestos remaining in the residues from friction processes have been carried out *diich indicate how minute is the fraction of asbestos released In the application of-friction. The latest report, 7' from Germany, confirms that technical investigations In recent years have repeatedly shown that the dust generated by friotion of the linings in use -- as opposed to dust created .O - I -8- during the finishing and handling of new linings - as a rule contains only traces of free chrysotilc fibre, i.e. of the order of 1J5. The working party was unable to provide clearer infra-red spectrographlcal evidence of chiysotile. Under phase-contrast and eleetron-nicroseoplc scrutiny, the dust contained Just a few isolated fibres which could not even be definitely identified as asbestos* This is consistent with the investigation by TJX goverrWEnt and industiy investigations'In 1969 vMch reported that the free asbestos content of wear products of drum brake linings rarely exceeded 1JS. (in disc brakes the content was even lover.) . The lendix'investigations for 2JI0SH in USA in 1975 gave a range from 1.65^ to O.OOJys -- only three tests were above 1/S and the overall average was This study also determined that only j.2jv of the asbestos content of all the wear products over the whole range of US motor vehicles became airborne -- estimated at 50^0 lbs. annually.^ - , _ - * * * , ' . 28 The Ford Kotor Company carried out a study based on dynamometer tests which shoved that during brake usage less than 0.025'- of the lining wear was released in the form of free asbestos. The stu^y estimated "that concentrations of asbestos fibre in the urban atmosphere in the US due to brake usage vac less than 0.07 x 10 ^ (.07 nanograns) (less than one millionth of the 2 f/ml occupational control standard). I'easuxen.ents carried out et points of heavy traffic concentrations in- the UK by the Asbestos!s Research Council, tinder the observation of the TUC Centenary Institute of Occupational Health, also found no greater concentration. Even in the underground `railway system, this survey found the asbestos content to be of the order 10" s/t^ to 10~^ e/^ (10 nga - - to 100 ngs/m5)24 ' .* Finally, some observations made within the last three year* by two occupational health experts, on occupational risks and cV* to the ***& 5>a - Tr. John Gilson, ''reviewing esbcolos ?.s' nn occupational hazard 5.n a central croup in which he includes friction naterinls, says "Despite the thousands of products containing asbestos, evidence of ill effects froa their use is very RMali". He adds the qualification that occupations . involvin'; brahe shoe maintenance have teen shovn to he et riGh in the past. "Although nost of the asbestos in brshe shoes is degraded, the dust in tae- brthe druns st^ll contains a email percentage of asbestos". "The ne^jiitude of the risk (of estestosie and nosothe1lore in there ve.rVing regularly in this employ :.ent) is not known hut is likely to re s^all." Professor fielhuis" , 22' in his report on public health'risks, conclv-des "There is ' evidence of no excess r>sk of nesotheliona fro:n asbestos pollution which hss existed in the li^i^ibourhood of ehrysotile and amosite ir-ines. There is ,.r.c .e vidence of a risk to the jercral public at present". Later he repeats *i:`*s view in hir. c?r"vrel conclusion "There is no established evidence that tree smb'ent exposure, as prevalent in Vest cm Luropsen countries, at this moment carries such e definite risk; houever, there exist too nany *.ir.certa'*ntic5 to deny such-a rir1', though if the rich was substantial it is lively it would have been detected by now". \ ^ r.r"^i"?7o?T5 -iure There can be ?n occupational health risk in the rjanufseture of esbestos- ?rc' friction ratarirlc. However, experience hr.s shown th?t this is a very 1'' i tec hsrlth r*?': and that it can be effectively controlled by veil tested equipment and.Work procedures. *, "t^nl^rds based on extensive experience in the industry have been Established and equipment ic available to maintain these standards so that the occupational health risk con bo controlled. In nany countries these Btfntordc ere enforced by legislation, but In any case trade end industry have an oblicetion,. es with any occupational safety problem, to inpleccnt the effective rich prevention Dee cures Which have been developed by I In cor>f. ron^iiir.-ns irjvolvfnj r etc., tfctre rwy le e y*rt- 1 f.- rn. St1 5;.i r J('y c.pjj p:-ov5.e 5nfor ;=it^.on to cnsoro . 0;&t v*m*3 Jcv tU;- era wr'or v'.ot c'reu. tlmccs pucti ricVe f.rn price end avoided.30*31*3233, T!' ~ >v> .* it" J i.f.e *n<-. cr- ii*.:..t, Lr- -- 1 ( *. 4*. to tftU th?'. so. *r- 'r >:- Pi" r'?.- 'ry ^ .1 o c 1. ( c. V c c. a~'A-n y 'i~r~ *: *r-" v--cr. * * ***,*/* n * W*'I*I* 7'Tr"7T;-* Vn!rl.r, - (^r-' `v'y) ~Vcn;r*conJrn`f 7! rcl: TTnJ, P.'.mrbh, * V= 1 ** s. "L'.'r.t ProMf:r" the U.-;j of /.s'cntc-s Proceedings of the International Conference on Pneumoconiosis Johannesburg, S.Africa. 1969 "antorel?'t, 7:-*rp, Ar-"Ftr:t avid r>'C'z?,L; T* R/'rMr.ry T'-yr ru't-.vr-jr* of Asbestos? s". If r-v c-?l L=voro -z (7 ~ S) ??$ - rsi J-v.l;* -.57?. " Ann, C-.F.: In i iV. c> TAn* ?e*`*1 I^v-rio, Torino, f:^y.r. S-msy of A^Vf or tonally Z::porfd Perflations". 1/7?.-. . . - *. * . Iniomal'c?i*l K'jovizy f.;?Research on C?:vrr. I.A.F.C. r-crifijrrr1:^ on l\`r-l"aiior. of Care-'ir.oyenic Tic*: of CW.osIs to . .' ; . .- .* Vo?..Ar-V-sf'a. . ?/77* ** ` "SelEctcfr vvilton evic'.-r-jf-e ruVviitcr' to trie Advisory Corbittce on A scoot os 77" Fealtis end Safety Executive, VE. 1^77* . *, t Cross, A,A, former 1-3rector General, Asbestos Irlom*fiorip.l . As roc ietton, London. "Process in the Control of Achertcc Lust 5.n the VorI*nlnce". Ti*V-j ret ion"*! Ccnfryt: os on rr-^v^ocouiorJc, Caracas. roici.*A-ar 1?7-* Goman ?ede?'etton of Industrie! Acc'nent fjr5 Safety Insurance 1* # Corporations I.V. Perofajc-t.cr-i'r.ncV.ft-n (`horn,'AGcicj-xy). he search Report - Asbestos. ',lnvestii*atlcns' into Health Hs-p.rdc throu^i Lusto by Brahe-Itnin^s containing ARbcetos**. (Analytical. epideniolojical and aniresl. investigat Jons) 3er!e.tber 176 " "Hyg3 ene Standards of Airborne Asbestos *>urt ~. tise vith the Asbestos flegulations tt t* ,, _ a_a__ tJ.E, Dept, of SEbgs*wSi~ \ c 9 10* .11 .12 15- C - J'cs** l-: "r.n* K'iliKn and "shuts (Di>st F.eooarch Institute of Federation of 7nA"irSnl Trade Associations (Pej'.ifs^'er.rosrenfcheflen). "cum, Cer./:), and Fmclip: Va; (Bavarian Stoic, Institute for In*i5 :-'rirl SffoLj't "jn<ch) *'Iverli^;5.onrs into the retards ty het of nrVe-Btco-contnin'nf "r-cifon linings". June 1>75. Cwfovc.7jcc on Thcj-osri e to An'S&tttc-B cHr'i^ "ithe and ciotoh Fr.'nl-rpr.re. Fr**.'itwood, Ih-.jlrr.d, !>rch 1?6?. ) L:-e C-,L: British Lsylsnd, Lonybriz.je, Fimin^h-ir!. '"er.icviny Bjsts from Brake Asr-o:-.b1. its curing Servicing - Automotive Cleaning !I*thoca,,. V) Fetch,!)., Ferodo, Ch?.psl-er.-le-?r11h, Derbyshire, Frglend . ' -* *' * *. . "'Possible Alttii-ieiives to Asbestos e.r- e Fraction Ilsterial". ) Fhig'it, K.L. end EicVirh, D.E., Kedioal Sr mices, Ff-rd of Britsin, Brenlvoofi, Fssex. " "Ir.wr-t i*i > ons into- Alternative Fours of Control * for' Dust vr-ereicr during the Cleaning of Brake Asr-eiiblies end Dr.irs". d) BJckinh, D.., end Knight, K.L., (as above) "Krpnr-nre to Aebt-stos dv-iins tu.tA.*: MlritCTeT.ee11. V Artels of -- Coc'.ypatione.l Hygiene. Vcl. Vi 1,,5/JC. * Bentley. M.L.; Kintex, Cleokherton, Yorkshire, Inland. Personal communication to A.A.Cross - Asbestos Busts - test during drum brake maintenance. May 1974. * * ' *' _` Crocs, A,A,: Chaiman, Hiviroreental Control Committee, ABC _ ,' * % Bbyl-'vri. "AFlcctoc Bust in Friction F'-teriPlc". September 175* ' ; Jecko, BuCharme, Comers! Bendlx Corpn. end Lr.viromental Protection igency, USA ,fBrr.ke anti Clutch Emission during Vehicle Operation". . Automobile domineering Keetlng, Detroit, Elehigen, USA Kay 14-18 1973. ' % c U. *! . c V;. A -'a C T?:jo1, Ar:>i\'^n, 'vicholson, L:-)\y>r: J*:v'it Sinai School of Jroflic;no, 1J.V, VSA. "Arvetcs 7\p: kvtc- o-.-;--n" "5;.v5ce Lining I'eint*nance end Zeppir". A*.orIc;-n "r/.'.e ir; al Uyjiene Conference, !';*pni, VSA. (tbsirect ?< j) M&y 174. ITicholpon, Yj !%";nt C*swi "cV.oo'1. of I^dic're, K.Y. USA. Zyjncura c'ur'i ^ Xvfi'rc- Maintenance end - June 1?7*. vr:d to l'e full vrruion of s'nvtrent r.fvd pIovc - 14) '.oh!, "olff end VelE?"^r.: jlvnt School of . TV-dioz-np, 7Yf VSA. ,!Arhc-ptop Zxpcc'jre i'ir"nj 7r?*<c Lininr M^inleri'nc*; rnd Xapn'r". &vircmr:vt al ?.c ?e-rrch 12, -110 - 122 p* * * * * lector - . , ' fobl* l-rn0er. T^ ir ontid-'s, Volff, Selif-roff: Mount Sinai School. *of K-'r*, ' c 'n.'r , ?rf,. VSA.'"AjA'Dstop Content cf fust !Znco\vii?rP. d in "**** c T>ii'it-i`.pncri m*' ^.r.*^2ir,,. Proa. P.oyal Soc. Keel; ?0: 12-7-7 * i-' , ~ .K.: Sverdlovsk Inptivic- cf Zrx-ur, "yfier.e-i?n5 I;vl->ctr:.rl.z:?f.pscs, l"S?.. tS/'i: cn? Jrevcr.t'm 7V?.^;r~s a^rinst IX: 7>r ful to ". "ef.ltk of Yerkers". (fropier V). 15175. '.IT.: r *;` cr1f5~M .h* Cr**: act'.cut, IM*. Terstnal 1: ; *;nl"V,, 1/ cf - = .i rrrviec- - r* re s in Ticr* o;.i ?:`.i`5 S'-rf., Crfifcmit -- r.T.v.c..". mi* feliroff. 1*75* ` .. - * . * * . , .. Lorir'or end ".ohl; Mount Sinai School of Medicine T^T, USA. "Anl+nto" Zrpc-'tie of T'rr.Vc Peps* r Yorkers in the US". International Conference on Occapatlrn?l Health, Brighton, IhClenJ. rj>i enter 1?75* . O I* .. c K* n2t. 25. 2. 27.' L 28. 29. -4- :`:;:it 3*ir-\ Cchonl of SToAlftijw, :*>:,* ;-rA. "C<v ;>n:v-ilve Torts' 5 Ly /Ccperien-.e of Tl-ive Co'o.vis of .*.< or los Vorbcrs. Int^rnat*cnnl Confer iTtCfc ,t.n Ce.e''yfi,r.'*:\ .walth, Coo Itw ?r>. . *. SieL'mis, ?cof. B.L.: Cor?r>el Irb-Tcelo^*, ty of k.'i terdan, jrether-?:i''s. "Public F;3?.*ih "'.3**.' cf Itvj* sure to Asbestos".* Report of a `or 'ng Group of h-p! r' i pvrg^rec frr *.v,r Co- .liss?on of the Ini'op'. ?n Cr.r:r :r' f -op., jv?: rr t? - for Social Aff.v:rr, Foalth and. Trie'". "*577- . ?>cV: stben, ~V jn"r end Fonnvrd; Centra c.e rorf-: cb* crnor-:r.t Ceclninue, ?r:: . "La Pollut'or* A*':iCsp'ierS^-e VrVf.ire par 1*Aspecte". JoHrnoas d'Btute svr la Tox-joMc^ie Tr.J'*-r-!.r5ellp,' ?*ris. June 157.5* . Anl-criovis Fc-ppprch Council/Tochnele, EiiT-nd. Personal corjnuni cation to A.A.Cross* "Investigation into levels of airborne asbestos dust in the London Underground, etc.". 1978. JobnP-T'-anvvlle; Lenver,. Colorado, USA. 3oF.ir.-r- Tv.V.ey - Cc-br* Tiring Tni^Bion ^577. ' . * 4m .. `4, .* * ' ** Vinton Laboratories, Surrey, England. "Asbestos in the tcifif rgronrd no cause for elara". * - ........ Tmffi.cy, 3.1/., Ferofio, Chapel-cn-le-Frith, L:-rly: hire, England. Personal CoamSiiostion - Asbestos Content of *><-.-: 3r:-ducte freo Friction naterials. June i?6. * Anderson, Gealer, UcCur.e, Spiys; Ford llotor Company, USA.. "Asbestos Enissions from Brahe Itynamopeter Tests". . (p.ef. (- ' ' ._, , " 13) Gilson, J.C.; forner Direotor of Kedloal Be search Council fru>ivnrtftnTiloBis Unit. Ptrnarth. TI. Personal ccaasunlcatioB to c T\ ?1. . /rr r -- "'ubectos Tr*oiion Toirr:`'In etc. - Cr.nlrol : Owi(*c lTo.6M. Anbestnni *5 PrA-if^rch Covnc1!, Coevalitee 3.0. "ox CV-rMi^ton, Yfr* '-Vive*, rjijT*vi*. r**o. 1J70 (j.?test r?v.t.*f!cn - ]7>ro)i 1 977) r"5-rc *Vo':!n^ v<tb Arbrstos -^r?ct ion t-n3 Ar.ii-7riction !>.*.* Tie's". A?3 - See item JO. ^rco; L-i'v'eci Vcm: Prf.cMeics - 7Vorir.fitier. f.nfi Yna of Asbestos friction IV\\eriets".AIA/NA- ebc-ctos Inforratfon Arsociation of 'Torth /.'-trice, '.fffiViiv-tcn USA. _ "Priotion "fitr-ricls Vori; Practices Cwlre"; PrSctlon I "a`.triple St.irSenis Institute. "ov Jc-rsey,. VSA. October 1573. 1/ .V.-jV,r.t-v 1QG1 V O c ** V' > r c 7*>. "A. mr . "'cbecios T-irefi ~r*ei3on "pi or;* *>3 r; etc. - Cr>n`rol n"cl Apffcty Onif'c IV*. 6M* Ar.bcstorp'c r^:-,r,irch Cc<i'c4l "jjvi '-nt*!2 Co/*t*'ol Coivvsittco p.O. "ox 1?, C`Ur*>V.":ilo7i, Vf*rV *M vo, Tt.J'.-y,*. 7-c. 1?70 (latest rev*f?on -- l'firch 1 on) '"r-fc 'Vo*:1nj v*tti Ar-Vsios - Tr?ct Jen rrvf idi-Tj'ictlca. :*Rte*rlf"8H. A3? - See item JO, **ort: Pre.cJic.es - TVbrication enfi Vr.o of Asbestos ?rction J>.-ioripTs".AIA/NA- Asbestos tnforr,pt:on Arsed at ion of 'Torth /re dee, WsMn^cn lTSA __ "Friction rd.r.rJels Vor): Practices f-jir.e"; Friction !*striple Stnr.'an's Institute. ?r.?'e:'-up, "ov Jersey, VSA, October 1$73.1 1 /. lt:d O o