Document peLzr1XeMzdKbYZ4yeoL4MxGB

ASBESTOS INTERNATIONAL ASSOCIATION (Limited by Guarantee) 68 GLOUCESTER PLACE, LONDON WjH 3HL MEMORANDUM TO: >2ri>er Associations FROM: Director General AIA/7/3/?ROD 12 February' 19S1 "Asbestos & Health in the Friction Material Industry11 The attached position paper on Asbestos & Health in the Friction Material Industry is forwarded for information. It has been authorised by the Executive Committee who reconmend that it should be used as a background reference paper to help members deal with questions in asbestos and health which may arise. O >-I v'7/j/P?02 ATV'ITOSAlfT* }.T* VT. TV TH.-T F?JCTTPV !'KT^Z *1 Itrr"sT;:Y r"V*fc Frcbl Hrposure to esbertoe dust is reco^isod es a potential occupational har.ard. Azr>r.- work people exposed to high concentrations of respirable asbestos dv.pt, (such as is taovn to have occurred '>i*fore present day dust control re azures and work procedures wore introduced) casco of cer.cer and prb->sIon's have been reported throughout the world. * The difficulty of reliably identifying the occupational history of those where health his Ken affected .-any yeers after hee resulted in any contact with *'" asbertos bein$ reocrled vith caution and all materials containing asbestos heir.f attached indircrireinately. Since friction notarial is widely recognised as one of the products for vhShh asbestos is rn irjpoTtent ingredient, it has attracted such attention. Indeed, the asbestos industry, in reminding everyone of the vital role plcyed Vy asbestos in brake lining, has stimulated such attention. T*e^erthcloas the occupational health record of ths asbestos frici.on atcrirl industry is good and only a few cases of asbestos-related disease fvc on record. However, the widespread use of friction materiel in all types of vehicles has raised the question of potential pollution of the environment vith fn assumed consequent danger to the health of the public. Thr fraction notarial industry, theroforo, ha: two basic problems. The 7'i-i, ocfwprtional health problen, has in r.ary ereas liter, resolved. rowav*r, the industry must continue to ensure thet those employed in the rvur:f?cture of these rater.lols ere not exposed to dust levels which ere Iv-rrifol. An extension -f this pr^blea Is the need to or- -re that workers crplryed in the subsequent use os friction materials, ei-ner in the fitting- of the products or the maintenance of vehicles, are not exposed *o bereful dust levels. -2- 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 way Justified by the evidence). A climate of concern for the effect on the environment of expanding towns end industries hae led to the motor vehicle being included as a sipiificant factor in this pollution. This 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 autonotive industry ie also under attack for a number of other reasons, (e.g. pollution, waste of resources and congestion) and would gladly be** without the asbestos problem although it must accept that for 6oae years, current models of motor cars will need asbestos-containing material for 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 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 dally wearing down of brake linings and clutch facings. An example of this confusion may be seen in the evidence given to the TC Asbestos Advisory Comaittss, 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 will be reviewed under three headings, the first Cvo covering the Occupational areas of Manufacturing.and Servicing, and the third heading covering that of the tencral 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 Z f/ml* standard have led to further improvements in dust control and ^here are now many operations where levels well below this maximum allowable concentration are achieved^. Very few cases of asbestos-related disease arising from friction material'smanufacture 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 veil as to the ehrysotile asbestos more generally used throughout the plant* The asbestosis cases vere all involved in mixing processes where masks should have been worn. In the same volume of evidence, a report from the two Cape Industries1 factories manufacturing both textiles end 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 nan hours have been worked on finishing operations of asbestos-based materials; though the dust concentrations associated with these vere at one time very high there * f/m' (asbestos) fibres per millitre -4- has not be-en a single diagnosis of asbcctosie es a result of this exposure". In rore recent years (lp9 - 1976) however, average concentrations vore veil below 2 f/nl following continuous U-iprovc-rjrnta in dust extraction methods. An investigation in 1975 by Eeidernanns, Kidmen, Schutz end Prochpzka^ into dust hazards which might be associated with the manufacture and use of pfbestos-cent ?. r.ing friction matertnls (undated in the Serearch 7 report of the Cerr.a.n Lervfsgenosscnschaften quotes concentrations of n'ere-dust in the range of 0.09 to 0.20 ng/r^ during grind 'rg, drilling, saving, turning end pilling operations (the current 7?.* value is 0.10 r.g/n*' or 2 f/rl: on this basis the current range is 1,6 i/cl to < f/rl), on average just below or just above 0.15 or *r/zl* Puch operations, unless subject to dust control, will emit duet containing asbestos. A number of surveys of such operations hsv* been carried out in Gem any 7'9, US 10,11,12, VSA 13.14^5.16,17 ari 5.5,8 nd it is clear that, under some conditions of working and where such operations are carried out continuously, durt concentrations above 2 f/al (or the TR of 0.10 F:g/n') can be reached. There is some evidence of effects on health among ren engaged for a long period bn such'work. I'edicel end epidemiological investigations by Professor V'oitovjts, Valentin and others { on workers who bad been eont Jnuounly exposed for at leaet 10 and up to 25 jeers to asbestos dnrt suggests e similar risk level for nen employed on finishing operations g-irding and drilling) in the automotive industry,to the* risk of vrrkerr. in the r*nuf*ctutlng industry ' . + It *? i-oted that the automotive industry group studied bad had long 9 exposure from a very early age. A group of nen carrying out brake * TfJl = Technical Control Limit * Out of 94 workers (including 43 vonen) in mcnufacturir?. there vers 3 probable cases of asbestosis and 11 "possible". Aiiong 63 Ben employed in finishing operations on brake lininrs in the automotive Industry. 9 <\.-vi - . ............... * ** M * " * -- naJntencnce scr-vlcee with exposure primarily during the cleaning and 'brushing out of "brake drua duet gave little evidence of inhalation effects in spite of long yeAre of exposure. Professor Selikoff's investigations 19 quoted indications of abnormalities in 32 out of 87 motor vehicle nechanics (6 out of 23 with five or more years intermittent exposure shoved 6igns on X-ray of changes consistent with asbestosie). Another report of the saae investigation quoted 24TA of 5y brake service cechanics showing chest abnormalities not necessarily arbcstoc-related and it is eaphesised that there were no confirmed cases of asbestos-related disease. Dust levels quoted in connection with this investigation (in DSA) * * refer to Bean concentrations for blow-out of brake drums, grinding of used linings And bevelling of new linings of 15.9, 3*8, and 37*3 f/sl respectively - nuch higher than any found by any other researchers. 77o information is provided as to the duration of these 6anplcs - they are frequently referred to as peak concentrations or the xcean of a irucber 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; sons chrysotile was identified by X-ray diffraction. Fibres identified by electron microscopy were all below the minimA um'sire specified In the definition of asbestos fibre (!* 5 in length) . Zt should be noted that the methods of sampling and the criteria for measurement of occupational environments did not confors to the methods used by governmental agencies and by other investigators in Germany and EX. Ter comparison, concentrations of asbestos dust during brake maintenance reported by Eicklsh and Knight ^ shoved an average daily exposure of 0.65 f/rl (range 0,21 to 1.12) during brake service of 11 cars. During truck brake service, the average was 1*75 f/nl with peak, during cleaning of the brake drum, of 7*09 f/ml. , The German investigation in 1975 ^ (now Incorporated in the Berufsgenossenschaften report ') recorded high concentrations* In the brake service department and * 0.03 to 0.79 end vifh background workshop atmosphere of 0.03 to 0,05 sg/c^. c- - vhurc rackin?nj vac without duct extraction. Although Mfh concentret'ons of C^r-i wore observed during blowing out, no chr-yot;!* pc^s-sto? could be detected by infrn-red spectroretry, and--the iniivMucl fibres which could bo detected optically could not be identified es asbesto.*. The Central Tnvir<vr^-nt T-.ir'nj the 'i sn of driu.i brn-'es, disc nafe or clutch fac'r.^c, p .ell 0'ir.r.i >i :os of t^e ccrfrce of the friction rater'll vo*r, M-cy. Tkvce :.t3terial6 contain botveen^JG^i to 6C>\' of asbestos, end it has bc-e^ assurod by sons that thereby larje quantities of dar.^erouF asbestos dusV are bein* refpla-.y dischar^d into the atnosphere. This, tt is argued, creates p dangerous atrosphore akin to that vhich has produced ccteetcs- rolcted d-erase (especially cancer) in some vorkinf environments. "tree the estirwted consumption of asbestos in friction r-aterial is annually over dO,GOO tons 22 for Europe and oyer 50,000 tons in the V$k the ecovjsts -jvolved s-ro substantial* An estimate carried out by the Fendix Corpcrnt*on vith the support of the US Ibivironnentel Protection Agency (LTa) calculated that the amount of friction tutorial vorr. *v*y in brakes end clutches annually in the V3A ia around 60,000 tons,1'' (of vhtch 57000 tons It the asbestos content i.e. $0;'. In Europe the content of brake I'n'nfs is nearer 3C5'). However it is clear from neacurenents n?de at a rvvnVer of locations vith heavy road traffic that insignificant quantities of '-espirablc asbestos d*t arc *?o esitted*^*^ Ihe c*r t Irpcrtf-nt' footer in dispelling anxiety is that the asbestos content of the voar products of friction material is not eaitted into the atnospher? in the for.* of respirable eeboetos dust# ladeed, a cumber of ambient air investigations indicate that it,la difficult nowadays to find asbestos fibres, in any aifinlficant quantity, regardless of size, in the atmosphere - even in the vicinity of asbestos oMnifeeturing plants# * Measurements of the anbienu\ sir even in heav*y traffic conditions do not chov * -- - --A ' --' * -7- confined tunnel environment eight be thought to create the worst conditions, no significant build-up of asbestos du3t hes been detccted.^'^'^* 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 vhy asbestos is such a vital component) is sufficient to destroy the original structure of the asbestos fibre, from-a temperature of 450C the chrysotile structure begins to convert to a non-crystalline amorphous phase, leading to a loss of stability of the fibre structure. The mechanical strain applied during the braking process has a pulverising and grinding effect, leading to disintegration of the fibre structure. The German report ^ calls it *'a kind of micro-milling so that the dust no longer contains any fibres".^ From a temperature of 650C a nev crystalline structure develops called Forsterite, vhich vill be fully developed at temperatures of above 700C. Generally, forsterite cannot be traced in brake lining dusts. This neons that temperatures beyond 650C 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-spectrocetric or X-ray diffratcnatic methods). Examination of the residue of vear products in brake drums confirms that the asbestos content is usually less than 1# of the residue. 1 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 vear . product show that this is not ao. Various investigations Into the amount of .asbestos remaining in the residues from friction processes have been carried cut vhich indicate hov minute is the fraction of asbestos released in the t application of friction. The latest report, ' from Germany, confirms that technical investigations in recent years have repeatedly shovn that the dust generated by friotloa of the linings in use - as opposed to dust created & -e- during the finishing and handling of new lining - as a rule contains only traces of free chrysotile fibre, l.e. of the order of 1& The working party was unable to provide clearer infra-red spectrographical evidence of chrysotile. Ujider phace-contrast and electror.-aicroscopic scrutiny, the dust contained just a few isolated fibres vhich could cot even be definitely identified as asbestos. This is consistent with the investigation by UK govemnent and industry investigations in 1969 vhich reported that the free asbestos content of vear products of drum brake linings rarely exceeded 1?j. vJ[la disc brakes the content vas even lovar.) The I-endix'investigations Tor 1TI0SH in ESA in 1973 gave a range from 1.65$.; to 0.003;j - only three tects were above 1/a and the overall average was 0.25L This study also determined that only 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 Ford Kotor Company carried out a study 2Q based on dynamometer tests vhich shoved that during brake usage less than 0.02$,' of the lining vear vas released in the fora of free asbestos. The study estimated that concentrations of asbestos fibre in the urban atnosphere in the US due to brake usage vac less than 0.07 x 10*^ e/b? (*07 nanograns) (less than one millionth of the 2 f/ml occupational control standard). i!e?.sure:>.ents carried out at points of heavy traffic concentrations in the UK hy the Aebesiosis Kescareh Council v under 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*" to 10~^ (10 ngs to 100 ngs/m?)24 Finally, tone observations made within the last three years by two eminent occupational health experts, on occupational --- -0_ Tr. John'Gilson, " r^viwin* rob^olos ?o nn occupational h*?*rd 5a a fr/.-rrl To\>p in which he includes friction natcrisls, cays "Despite the thousands of products containin'; asbestos, ev\d,*nse of ill effects fro2 their ue is very p:ia11". TTe adds the qualification that occupations involvin'; brake shoe r..intcrnce have Veen shov to be et rick in the pest, 'Although nost of the asbestos in brake shoes is degraded, the dust in the Vrc!.e drone st*'ll contains a snail percentage of asbestos". ''The r.2nitude of the risk, (of erte&tos'.s end cer.othel ioca in there v-`-r>in ze^-ilarly in th's e:.plo/'.rtnt) :s r.ot Jmovn but is likely to re Professor firlhui*r, 2?. in his report on publ1ic "health risks, concludes "Tnerc is 4 rv.V,i*cj of no exceos :c'sk of mesothelioma fro:n esber.t-.s pollution vhich* h:?s ex.'rted in the 2;: ^foourhood of ck.iysotile and ar.osite nines. There is t.z evidence of a risk to the jercral public at present*'. Later he repeats v $ v.tev in hie ;^r>r?l conelusion 'There is no established evidence that tr:e MV*nt exposure, as prevalent in Vest cm Luropcen countries, at this i5ior:2nt cr.rriec snoh e definite risk; however, there exist too nany v.r.cr-rt%*nties to drr.y such-a ,rirvf though if the risk ves substantial it is lively it vo'>lr hnvc been detected by now". There can be an occvpationsl health risk in the manufacture of eabestos- V friction rierS*le. However, experience hca shown that this ts a very 1:* i'.ef harlth r*r'; and that it can be effectively controlled by veil tested equipment and Work procedures. *% "t^.:*rds based on e;cte-nsive experience in the industry have Veen established end equipment lc avail eble to maintain these standards so that the occupational health risk can be controlled. In many countries these stsnCtrdc ere enforced by legislation, but in any case trade and industry have an oblicetien,. as with any occupational safety problec, to implement ...i . > - ("r r ' -) In cor*-*. :r. rojyUif-::s* iriv'-lv'rjj ^ fc^*srntirr.s`T !%".*rn. *i V r.' v.j, etc., Vnore rny to p ?: r-v'C? .`ofor -i^on to cr-cvr: tl.'i't r.-ri -r/rr'l'n'i ''r'-*-* v'ot c'rcu. rlrr,ccs ruct r{r/. g r.on ,1 uv ,v,!.6-*' c* n .v'O fcvc:.<..ftd. .30, 31. 32*,33. .*r.d . r--. :;r r.-vir v to '>11 !>>-. r:. tdtl' ry i-=1 r 6 V / - r-- 1. t. ^r r. S' 7.* e. 'bVi r., (for ' \*.y) "Vou .no r.-p >:--* rob Vn5, *!**. 1:: Vi-2 Us* of /.* JV^'ctc". Proceedings of the International Conference on Pneumoconiosis Johannesburg, S.Africa. 1969 i, Ar* p ' ;:i p.'.<4 tr:; v.-> 1 r_-* of /raster' 'f-.-'r.: cri ' (7 - ?) ?:? - *:i Zr.~\i v A o I \c '**1 l'3c.; *; f e^* "v' *' t"**" c*" /.sV*5` cr C?*"'* v^cnsll'' 7~.jy*.~^ Po"r*oJ z> A-C Tnif-rr*. i'enl f - Research or. Oivrr. Z.A.P.C. -cr/^rro-'S c- iVr*l"*iir r. of "r'.-'o'...ow3;'iic A* c*: ef CW.o* s^s to :y.n. 703:14 v-77. * "Selsctoo vviilM: eviewt. rv.V**iitcr* tso the Adviccry Comities or. ApVc.rios 1?7^-77M T^rlzl. nnc Safety .:oct;tive, VT.. t*77* Crorr* A.A, forrer I-Jrecior General, Asbiete* I:. lem'-timel AsrocJation, London. ''Progress in the Centre! of Acbertcs I^rt in.the Vo:l7)?.nce". Tk>.'-ri:*(vr*l.C-:r.frv:-: **e on *-oconier is, Cvr*-c%e. roMLv.-sr 1?7S G-omar ?**:(-ration of Ir.tastrifl Acc'nent an* Safety In'nranes Corporations' Z.Y. Peri'fsjjr.rj-i^r.r.cVfi^n (r^r.nl".C<r;vu*Jy). Research Report - Aebertos. "Invertflattens into Health Ha^p.roc through D\isto by BraV.e-Iirinys containing Asbestos*4*. (Analytical cnidanilogical and aninsl. investigations) Droo~ber 1?6. "Hygiene Standards of Airborne Asbestos Duct Concentrations for W* v^*V *V (V --* 7c-{<* r ,rn, K*;'ivn < r.n ~c-.-lz (TVst o Tf: tituJe of 7fefrr?tion of `rn-v*:trlol 7iWe .Associations (?i-.;f s je jjosr e>is c!-..?f t _ n "oin, ^fr.7 `'.chc: Va; (Pavnrip.n Sta'.c, Institute for In.i- ' rial C'foly, 7:r*ch) "Tmerli^t'ons i:sJ-o the r>c*rus Xy of .'rl r-*4 co-coniv`n'n _*; ltr-in^s". Jwne 1^7 C^pfos'v.'ire on "rp-.'i1; to AnVj sics d-n *r. "V7:e e:vi rAo\ch 7= *n! * e. P*'-.V.v-oc, IT:-***, 21:^3 nv!lt l>rch 7-c?. p) I:-e O.L: Ir.'tifh It; t LouJji-5c.je, ~ir-:ir<;hjr.. "r.vocvinj I'-sts fro~ -TVs):? A.?rc.7.7ur during Servicing - .Otcrr.cttva Cletivlnj !>thocs". V) r?tch,P., ?eroco, Ch*psl-er.-l2-?r'th# Derbyshti-e, Inland "Possible Alterast *vps to Asbestos f.k e 7r/.ct ten l>tcriel". c) Tr.i^ht, K.L. end Hlc'irh, I>#5*, Kediasl S?raises, 7crd of r*ritftnt ErmU*ood, rrsex. r^i/ons 'nte- Alternative 7oi: s of Control-for'Dust i/r-ersted Cur'ng the Clcanlr." of ?r*!:e Asr-eiiblles pan Dr-iss". d) "5c';:sh, D.E, ( end K.L., (as above) "Exposure to Asbestos dvrirj r*i-n*.e !>\r/.C'rr.cen. VZ Annuls of -- Cue; pat *0:^.1 7;-j:t-^c. 7c1.' y A^7C. Bentley, >!.!.? Kintex, Cleohhe? Von, Torhrblre, IhsAand. Personal comsunicatlon to A.A.Cross - Asbestos Dusts - test during drua brake maintenance. Kay 1974* Crocs, A, A.: Ch'iman, Zuvircrrental Control^ Costfiiiee, .A3C Bhylond. "AsVestoc Dust in Trlctlcn V*ter:clsM. September 175* #. * JeeVOf DuCham?, Sonera? Bendix Corpn. and Ibivl roamental Protection t^ency, USA "Brc.ke and Clutch Emission during Vehicle Operation". Automobile Engineering Meeting, Detroit, Michigan, USA Ksv li-lfl io*rv * M. ^ol, V -V'vr:, *`5 c'i< ;;n, L:-vw'-r: -inai School of J*c-oic :, N. Yt VSA, "k~\ ?z3.r'$ 7\p:z to - ^.'vke Li.nin* r^'ntt'/ia.icc fi.n<3 foT'orr". /cccrlo-'-n Ir/.vcr:3l lyj'ene CO* ,ve-nce, V'ptI, V$A. 22}) 7r.y 1$?/.. \M ."'Chr-lr'-n, *': *cv-oo1. of I>**.lc*re, ?*.Y. USA. ii .. nv,*oo:ro <Vj"?i * 7'r' r- tA ?<.; *5r*` - 1?7f. ('*' r ' v*:^ to fi'.ll v * :n on of s* .:;t ,b -A ptovf - 14) r.^ht, volff sro J.'vrit f'ti'i Zc'-orl of 'V.^ior-rj1'-, **Y V2A 'WrVc-etos Zyp~r\>re fwx'aj ?r*'<e Li nine r:r.:::e r-r.d Zepa-'r". 2iiviro:n?:*.tfil ?.c .r-;-rrch - 122 {'91''). ;?>V-r 1?75- 1?. fool*, lr-.;jcr. 3 Ircnt'.rt's, ' olff, Sslf.-*off: Kr-unt Sln*i School- of !-':*'c':v*, . V2A *7.? tosto* Content of Z`ist H^crwiter^S in c !>t-v.r.cr. m* r.r-oSr*'. T-rc-o. r.cvsl Loc. i'ef: 70:32-57 t, # , i T.K.: Svcrotc-vsV Tnrtf'.v;:* cf 1*V.-vit, anf Tr4I->rtr.J.r3.r??wrc*f Urs*. ^ts:ns trf 7revcr.t'>n TVarsns sfrLnet I-;*-; 7>r--fiil +-o - ;>*.ltV tf Vcrhftrs". (Chsptfir V). 1?75, ?** f.".; Cr: , 7?A. Ter^nal :**?: !'- ' 3 *>*:.' rf ?;:*%.<*#?--::j L-rrVfe rerviee Tor*:..., m,C r*;-:?., Cf.lifcir.ic- - TcliVoif, .Jtejvst 1>75 * A#>.o Zorir*or an! ZiM; I-Wont 3*nai School of Ke$ic?ne, USA. Zrpof Zrr.Vc Zej.fi'r YorV.ers In the 73". Interr.st'.onO Conference on Occ-jctler^l Health, Sri^.tcn, 2rclen3. taler 1975. I - /, n. Irhoc1. of `h '* *, M* t!, nr.'-ti va 5 rf Tf.wP p rf rt Vo-hers. * ** ;iM ' c ivi1. Confer .r-ct ;.n C-..'*1 '``1 r*1 `V 2i 2? 27* ?8. % 29* ie Prof. 5.L.: Cc*ror,e\ L"t"'i?\:'* Tt4; : .? t*r5?:% "JuMic -.V* rbestos".' ?'^rt of a "ov '`nj Croup --f h* Co -lirr.'cn cf the- :-n Cor:- :r'> !?. t ; vi3! for for:ol /'ff-V-rr, "f-'.lth pj-*c C'fc o 5sV*st.->n, ~i^rn end ~onri**rd; Centre rc rorf-: cii'cnnor-Tt Oc'r.inu3, -Mr . "La Pollut'or* /.f ..cspheric;* YrY-ij v psr I'/.s'-eot*", 7o'v;no?s d'Et`viJ*: svr la Coxic` V;_*e 7:/-.**:r*el 1 =, ?eris. Jvjie 157.5. .'.nlrrioKis research Council,"Toehcei.e, Lnpl'r.i, Personal cor-uunication to A.A.Cross* "Investigation into levels of airborne asbestos dust in the London Underground, etc*"* 1576* Jol-ss-V-willr; Lenver, Colorado, F3A. rontor. TvLv?" *ral:e Lidas Emission 1977* Vinton Laboratories, Surrey, England* "Albertos in the FnSfi^ro*' no enuse for #lara". T*uff5.cyt L.L., Ferodo, Chapel-er.-le-T'dth, Serb; ."Mr*, In^l Personal Coarnfeioation - Asbestos Contact of * Vr.r ?r'*drcts frro Friction Materials* June ipf. t 4 Anderson, Ceeler, J'cCur.e, Sprys; Ford Motor Conpany, USA. "Asbestos Missions from BraVe Dynaropeter Tests"* (Kef* as 13) Cilson, J*C*f fotner Lireotor of Medloal Beseereh Council * ".r,hor:fo? ^r'oiion **. I nr.' *> 1 r. etc. - Cf-r/re?. -v.d f^fc-ty r'-n; do }>.". At.'jc on* r- To '-'irch " ivi : ':;tO Cori>-o1 *o: ^Kt ce ?.0. Is, e:O-V.'-.i I go, Vor- i it , ?.rw''-rJa. T-*c. 1y?0 - r<%r'-:h 1277). "1 'f'-fc 'llj V to pi vc - iW.tim rnd Ar.ti-TvictJcn _r. s- c-. i -a' S K^Z - See item }0. t:\r-r.y. -,i "..-`fta ' orl: 7-t.cl ' '-C - *^ubric.Aticr: fnd Tr-e of Asbestos ?ri c t i on j" \* e r: * 1 e '\ AIA/ KA- lebeetos Xnforr?t*on \f c'-c ^ ution of !Torth k-<T*c*.t '->fiV-;r.;"ton I'SA. ''Tri^t ion r-' tr.rjgls v,ot): rr^ctiocs ?rict'o:i .T`s*.criais "tnrfftrd.s Institute. ?r.rfi:''UP, "cv Jersey, V?A. October 15?3, 1/ t--.. ltd \ O