Document 93Vj2327KB9kZe1kwBexmyQG5

AIA-2! i ~rr i 7; 7 ASBESTOS INTERNATIONAL ASSOCIATION 1 (Limited by Guarantee) ' 68 GLOUCESTER PLACE, LONDON WjH 3HL MEMORANDUM ^ TO: Merger Associations FROM: Director General aia/7/3/frcd 12 Februarf 1981 ''Asbestos & Health in the Friction Material Industry*1 The attached position paper on Asbestos & Health in the Friction Material Industry is forwarded for information. It has been authorised by the Executive Committee vho recottmend that it should be used as a background reference paper to help members deal with questions in asbestos and health which may arise. AIA-21 ' AI VV3/P? OD ara;-:;?os rr.*Tf" i>: ?k-: rkicTiow ?!tT^rT.*.i i< r"W D <0^ Hrpoaure to asbestos dust is recognised es a potential occupational har.ard. .fcaor.; work people exposed to high concentrations 01* respirable aebestos dust, (cMch as is known to have occurred ' -f:fore present day dust control rear-ures and vork procedures vare introduced) casco of car.oer and prb-> = ion's rave been reported throughout the vorud. 1'2 w5 The difficulty of reliably identifying the occupational history of thoF? viicr-e health has bien effected rns.ny years after hec resulted in any contact with **- asbertos beinj reerrded vith caution and all materials containing asbestos heir.c attacked indiscriminately. Since friction material is widely recocolsed as one of the products for which asbestos is tn important ingredient, it has attracted1 such attention. Irvicrd, the asbestos industry, in remindin everyore of the vital role pieyed by asbestos in brake linings, has stimulated such attention. i"a,rerthclcss the occupational health record of the asbestos frict.oa 'atrr'.al industry is {pod and only a few cases of asbestos-related disease arc on record. However, the widespread use of friction materiel in all types of vehicles has raised the ouestion of potential pollution of the environment vith sn assured consentient danger to the health of the public. Thr friction material industry, therefore, hr; two baric problems. The T'z~J., the occuprtinnal health problea, has in cany eres ht-er. resolver. rtwev*r, the induetry rust continue to ensure that those employed in the rnnufecture of these mtoriols ere not exposed to dust levels which ore lv-rrifcl. .tn extension -f this problea Is the need to or -re that workers employed in the subsconent nee o; friction materials, ei.ner in the fitting of the products or the aaintenance of vehicles, are not exposed wo htrnful dust levels. o AIA-21 I --2-- The other problem for the industry, that of possible environrcntal pollution, is more difficult to resolve, based as it is on emotional anxieties (which 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 t significant factor in this pollution. This fact together vith 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. I 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 some years, current models of motor cars will need asbestos-containing material for replacements. The friction materiel industry itself must therefore dispel anxieties about asbestos-containing products in motor vehicles by ensuring that the existing reassuring evidence it 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 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 (end 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 wearing down of brake linings and clutch facings. An example of this confusion may be seen in the evidence given to the US Asbestos Advisory Committee, where claims that the general public are at risk are supported solely hy reference to a survey of motor vehicle maintenance workers.^ AIA-21 - 3- 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 chat, 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/ol* 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 materiaT?' 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 ( . K cases had all been exposed in the manufacture of railway brake blocks between 1928 and 1933 or during the var years up to 1943, to crocidolite as veil as to the chrysotile 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 man hours have been worked on finishing operations of asbestos-based materials; though the dust concentrations associated with these were at one time very high, there * * f/m' - (asbestos) fibres per millitre AIA-21 4- - has not be-en a single diagnosis of asbcctosis es a result of this exposure"* In rare recent years (lj69 - 1976) however, Average concentrations vere veil below 2 f/nl foil owing continuous ii.'provc-rgrntb in dust extraction methods. An investigation in 1975 hy Heidemanns, KuJinen, Schutz end Prochanka^ into dust hazards which might be associated with the manufacture and use of pfbestos-contf. ring friction natericls (unitec in the Perearch 7' "sport of the Ger-.an i-enfsganocscnschaften cuoies concentrations of nlcro-dust in the range of 0.09 to 0.20 mg/r^ during grinding, drilling, fp.vr'.ng, turning end rilling operations (the current TnK* value is 0.10 r.g/c*'' or 2 f/nl: on this basis the current range is 1,8 f/nl to 4 f/nl), on average just below or just above 0.15 or *r/zl. fuch operations, unless subject to dust control, will emit dupt containing fisbcstos. A number of surveys of such operations hve been carried out i.n G. et--any 7,'9*' Iff 10,11',12 , tU,cSA. 15,14K^5.16,*17' and, e.lsew.here 5,5,*8 end,, it is clear th.st, under some conditions of working end where such operations are cerried out continuously, dust concentrations above ? f/al (or the ihbi of 0.10 rig/c'} can be reached. There is sons evidence of effects on health p.ronj men engaged for a long period on such'verb. I'edicel end epidr.-.'iolcgical investigations by Professor I'oitovJts, Valentin end others 1 on workers who rad been continuously exposed for at least 10 and up to 25 yo?.rs to asbestos durt suggests ft similar risk level for nen employed on finishing operations (~r hil; g"irdirg and drilling) in +he automotive industry, to the risk i**vl of vcr*:rr. Jn the r^nufactimlrig industry + * It vp noted that the automotive industry group studied lied had long 9* exposure from a very early age. A group of nen carrying out brake $ * TTil = Technical Control Limit * Out of 9^ workers (including 45 woncr.) in mcnufacturirr. there vere 3 probable cases of asbestos!s and 11 "possible". Aziong 63 men employed in finishing operations on brake llnlncs in the eutoraotlve indiistrv. 9. AIA-21 - -5- . maintenance services vith exposure primarily during the cleaning and brushing out of brake drum duet gave little evidence of inhalation effects in spite of long years of exposure. 19 Professor Selikoff's investigations quoted indications of abnorr-alitiee in J2 out of 87 motor vehicle mechanics (6 out of 23 with five or more years intermittent exposure shoved signs on X-ray of changes consistent ' vith asbestosis). Another report of the seas investigation quoted 24/; of 93 "brake service mechanics shoving chest abnormalities not necessarily asbestos-related and it is emphasised that there vere no confirmed cases of asbestos-related disease. Xnust levels quoted in connection vith this investigation (in ESA) ' * refer to me an 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/ol respectively - much higher than any found by any other researchers. J7o 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 el so clear that in the case of bloving out of brake drums, no asbestos fibres vere visible by optical microscopy; sons chrysotile vas identified by X-ray diffraction. Fibres identified by electron microscopy vere all below the minimum size specified A in the definition of asbestos fibre (l*e* 5 pa An length) . It should be noted that the methods of sampling and the criteria for measurement of occupational environments did not conform to the methods used by governmental agencies and by other investigators in Germany and IK. Tex oonpsriaon, concentrations of asbestos dust during brake maintenance reported by Eickish and Knight shoved an average daily exposure of 0.65 f/nl (range 0.21 to 1.12) during brake service of 11 cars. Ihiring truck brake service, the average was 1.75 f/l vith peak, during cleaning of the brake drum, of 7*09 f/nl. I m The German investigation in 1975 ^ (now Incorporated In the Berufagenossenschaftes report ') recorded high concentrations* In the brake service department and * 0.03 to 0.79 bg/b? and wifh background workshop atmosphere of 0.03 to 0.05 ag/c^. AIA-21 \ -C- vhvfc r nc'.iv-vs c*r.n* without oust extraction. Although hi^h ccnconl'rat' ons of C^r.t vore observed during blow-In; out, no chr-aot; 1* yt^estoF could be detested by infrn-red spectroretry, end.the Jniv<ducl fibres which could bo detected optically could not he identified ee asbestos. * The C-rn= ra 1 Trivi non- 'f nt Tr.ir'n; the a^ploat i on of i'ium brn^es, fisc n?dc or clutch fac'r.^r, F.ucll rur.r.i it:no of t'^e ccrfoce of the frictic-.n v-te-r'd sre v-o* r, fu;, Th-.'Ce .uaterials contain between to 60;' of aetestoc, and it h.ss bee; sps-cred by some that thereby larje quantities of d*n.erouF asbestos dull' . are beins re^ola-.y discharged into the atmosphere. This, tt is argued, creates a dangerous atmosphere akin to that which hes produced chtectccrolated d^srese (especially cancer) in cone working environments. "free the estimated consumption of asbestos in friction material is annually 22 * over 40,000 tons for Europe and oyec J0t000 tons in the USA the anounts involved *rc substantial. An estinate carried out by the Tendix Ccrpcrr.i5 on with the support of the US Environments! Troteeiien -Agency (LTA) calculated that the amount of friction tbaterial vorr. *v?.y in brakes end clutches airr'elly in the USA is around 60,000 tons,1'' (of vhich 37,000 tons tr the asleTios content i.e. 60;'. In Europe the content of brake I'n'ngs is nearer 3050* However it is clear from measurements n?de at a number of locations with heavy road traffic that insi^.ifleant quantities of 'cspi.rablc asbestos dust arc eo emitted. 23,24 '.he * nr.-.t tr-pariaat'feoddr in dispelling anxiet1y is that the asbestos content of the veer products of friction material is not emitted into the atmosphere In the for.*, of respirable aeboctor dust. Indeed, a camber of ambient air investigations indicate that it,is difficult nowadays to find asbestos fibres, Jn any significant quantity, regardless of size, in the *tnosphera - even in the vicinity of asbestos Damufacturing plants, 2d* Keasurements of the ambientx,J air even in heavy traffic conditions do not show ---- * *---- ' " * AIA-21 - -7- . confined tunnel environment night be thought to create the worst conditions no Bignlficant build-up of asbestos dust hes been detected^ ' The explanation is simple and ia 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-crystallins amorphous phase, leading to a loss of stability of the fibre structure. The mechanical strain applied during the braking process has a pulverising end 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 &ny fibres",^ From a temperature of 650C a new crystalline structure develops called Forsterite, vhich vrill be fully developed at temperatures of above 700C. Generally, forsterite cannot be traced in brake lining dusts. This neons that temperatures beyond 6$0 G either do not occur or are only very short lived. The decrease of the chrysotile content, however, indicates that temperatures beyond 4?0C are reached because the amorphous phase of the chrysotile cannot be traced analytically (by either infra red-spectrocetric or X-ray diffratcoatlc methods). *' Examination of the residue of wear products In brake drums confirms that the asbestos content la usually less than IJo 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. Tarlous investigations Into the amount of .asbestos remaining In the residues from friction processes have been carried *. out vhich indicate hov minute la the fraction of asbestos released In the 7 application of friction. The latest report, from Germany, confirms that technical Investigations in recent years have repeatedly shown that the dust generated by frlotlon of the linings in use - as opposed to dust created . d* AIA-21 l -8- during the finishing and handling of new linings - as a rule contains only tractB of free chrysotile fibre, i.e. of the order of The working party vas unable to provide clearer infra-red spectrographical evidence of chrysotile. Ujider phase-contrast and electror.-nieroscopic scrutiny, the dust contained Just a fev isolated fibres which could not cv?n be definitely identified as asbestos. This is consistent with the investigation by UX government and industry investigations In 1969 which reported that the free asbestos content of wear products of dnm brake linings rarely exceeded 1?j. ^Ia disc brakes the content vas even lv=r.) The lendix ' investigations Tor 2H0UH in USA in 1973 Gave * range from to O.OO^j - only three tests were above IJa and the overall average vas 0.23T;. This study also determined that only J,2Ji 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.1^ . . ' *` ' ** - 28 The Ford Kotor Company carried out a study based on dynamometer tests which shoved that during brake usage less than 0.023' of the lining wear vas released in the fora of free asbestos. The study estimated that concentrations of asbestos fibre in the urban atmosphere in the US due to brake us2ge vac less than 0,07 x 10*^ g/n? (.07 nanograne) (less than one millionth of the 2 f/ml occupational control standard). lTe-.suxer.ents carried out at points of heavy traffic concentrations in the UK by the Asbestos!e Hescarch Council, under the observation of the TUC Centenary Institute of OccupatiOTial Health, also found no greater concentration. Even In the underground railway system, this survey found the asbestos content to be of the order 10* g/m^ to 10"^ g/a^* (10 ngs - to 100 ngs/m3)24 ' .' Finally, some observatione made within the last three yeare by two eminent occupational health experts, on occunational --' AIA-21 Pr. John Gilson, ' rsb-`'olos ?c nn occjpoii or.al ba.?<*rd in a Cmorrl croup in vhich he includes friction n^tcrinls, cays "Despite the thousands of products containing' asbestos, evidence of ill affects fron iheir u=e is very p:>a11". T.e adds the qmlification that occupytiona involving brake shoe ru,.intcnnnce heve Veen sbovn to Ve at rick in the past. ".'.Ithoujh most of the asbestos in brske shoes is degraded, the dust in the Vrche drons st'-ll contains a snail percentage of asbrntos". "The r.2^nitude of the risk (of prlestosie tnd sorothel lore in there v-r^inc reyileriy in th*s e:.ployrtnt) is not Jmovn Vut is likely to re Professor 22 1 Ihuis, in his report on public "her 1th risks, concludes "Tnere is . rvbb-rce cf no ex.cet-s :c;sk of nesotheliorca fre.n esbest--6 pollution vbich* ins ex.'.ried i.i the n:^'.bourhood of chrysotile and ar.osite rimes. There is .ns .evidence of s risk to the- jenercl public at present". Later he repeats v - s v.'.ov in hie ep.--.>r?l conclusion "Pi.ere is no established evidence that true f.o.V cut exposure, as prevalent in Vest cm Huroncan countries, at this norsmt c;.Tiiec such e definite risk; hemever, there esiiet too nsny ur.cr-rte-'nt: cs to tlrr.y such a .rir1', though if the riek ves substantial it is li'-cly it `would hn-f brtn detected by nov". There cm be an occupational health risk in the manufacture of esbestos- v; ?r-r friction riarlelc. ITevcvtr, experience has thoun that this is a very !.' i 1.3?lth r'?): and that it can be effectively controlled by veil tested equipment and Vorlc procedures. *, "tm.:*rds based on e;rtc-nsve experience in the industry have Veen established end cqnipo*ent ic evaluable to naintain these standards so that the occupational herlth risk can bo controlled. In nan;* countries these stfndcirdc ere enforced by legislation, but in any cate trade and industry have an obligation,. as vith any occupational safety problec, to implement xv * fi*. , i * . AIA-21 l r,;--.- - ' >.("r - 1 r tn cor-`.5r. roMiil.'^s -Ir.v'.-lv'nj ' uj, etc., ihore rwy to p 1 *'* rn, '6 1 - :oTor .-it^on "to cr.c',r; i-rryz ^r.':rr*-rrl v.-v'-> .* v* it c ` rou. ~ lrr.cc s root 7 t,v it**' r.'n *'<? fevc :.c..nr.. 30,31. 32',33. e r-.?n price tr.d r--,' .-I i ' .? n-. Ci-' . .. A . ^ _ _ ( to j*n it--. k'> =1231-1 1 O AIA-21 .'n '' "-'~7 r., (fry ' yvorir p -rp1: Vn5, 'VI.-p. "Z > r.t Pr'-'M'' " 1:: IV; U.;.r>Z ; -.t t c11. Proceedings of the International Conference on Pneumoconiosis Johannesburg, S.Africa. 1969 T Tint mv-?. ' i, Ay*fini aii ru-:tri; '?. r>y yM r.yy of /.Pastor's*'. :r c*.o I*voro ?T (? - c) ?:$ - VI .VI 4 . . ..r-, . - Ir~ii V A o "vi**'.c *:.p. **? 1-Z L *!'*. j. x; f-r.r * r,"y o'* ' cr C cnslIf Po_--r? 'o;-.q", t. '-r:' 1**7?* . . . . *::!rr- i 'crj-l '-c:'.:y f - Research or feivrr. I.A.Z.C. Ji-cr/i^rrp-1* cr Zvr-l"iic.- of "ftrc'Vo^e.i: c T.'.c': of CVr-rlcsls lc ::*n. vn?;*' ^77. -* * "Pel solco \-v\ li mi t v<c c-r. Apoortoo l?7t-?7" 1 rr.V-i Itc P- to the Advircry CorrAtice -S nnr Safely Ztcc'-tive, VZ. 1J77* Cr^rrf A.A, f'rrnr IJreclor C-croral, Asb:?lce I:.t".?.l Asrociation, London. "ZrojrcRS in the Control of Ashertes Irort in Vie '.*oil'nlnce". Ti-V.: -rt: r,rvl C: r..V*;;-: -s or; ?;.*. 'sc.'Miier j s, Cvr%c%o. Tmtt*V-*r 1? 7 - - Co mar; ?* At-rat Ion of Inljtstritl ice'nent hi* Safety Insurants 4 * Corporations' Z.T. Psrx'Vyz-'r.rr--mncV.fi >n ("orn''crr.r.r-y). Research Peport - Aebentos. "InvtFilyaliens Into Health Hs-ards through Dasto by Brahe-Iininr"3 containing Asbcetos'h (Analytical epidenioloji cal and anlral. invaaticatJons) Depcrber 1?7S* "Hy^Jane Standard* of Airborne Aabe-stps Purt Concentration* for ^<ra Vi *Va I *V^ A m - - - * AIA-21 3*c-; f* v 'ir.n, K":*uvn ? >*A 7-cV-itz {7>.r.:n 7"'titu'<e of fe-V ration of Tn-v'-:lj';o*l TlWc .'c?oc?-'<t Ic-ns (fei'.sfsjeriocrejifc/.jftcn) ~on*i, ^r..r.v), nnfl f r,c]if:l-a; (Bavarian Stale, Institute for Zn.'u ' r t r 1 S'Toly, ''u>*rh) "Tuver '.onr, the T>rsrus ly '.=t of or'. *.'co-certt n'ng ZV^ctie.n linings". June I? 75 Canfo on 'vrror.'ie +o AnV-sics <3 i' 'r.^ 'nice end Blulc.h or/e. P*'.V.v-od , L'-.^ex, Zr.yl; r/i, !>.-ch l>op. **) !:-e C.L: British Li; l*nd, la;;gar1' z.je, "ir-lngVjr.. I *,r,?:.-'0viny I/sts fro- -Brake A.?ro:Jjl i cr during Servicing - Alternative Cleaning f-thocK". -- V) fetch,!., Terodo, Che.psl-er.-l e-frith, Derbyshire, fngjani ''Possible Alternatives to Asbestos f.k e friction Material", c) Knight, K.L. end HicVirh, D.S., Kedical Srr"i*sf ford ofT-ri if in, IrpriU'ood, irsex. * "Ir.v aril Rations into. AHe native /oi:-s of Central' far'Bust t/reralcd Cur'ng the Cleaning of Brake Asr-eiibl it*6 and Brins". d) Pick:oh. D.C., end Knight, K.L., (as above) "Zb-yocure to Asbestos during Trr.`.s Iblrjtcrsr.c*". V Annuls of -- Crcvyatinn*'.! fyj:one-. 7c1.' -?#s Bentley, ?!.!.; Kinter, Claokhe* Von, Torkrhire, Zn.O-^nd, Personal comcunicatien to A.A.Cross - Asbestos Busts - test during dma brake r.aintenance. Kay 1974* Crots, A.A.: Chaixmn, Hviron*c?ntsl Control^Como*ttee, ABC . Ihgland. "Islcstoe Trust in friction .lerirlr*'. September 1?75* ' ** * Jf-cVo, DuCham?, Sonera? Bendix Corpn. end Lr.vi ronnental Protection `.gency, USA fBrr.ke and Clutch Zr.ission during Vehicle Operation". Automobile Engineering Keetlng, Detroit, Michigan, USA Kav V-1R I07t. AIA-21 ., '*i c'k-''1 ;;n, " v:! Tin?.'. School of I'o;nc: , N.T, VSA. "A-Wetos 7\?:k-re d-':.: LJnin rc'ii)'*.1 i=ncc end ITc^r* \r". .VicrI?.--n T:.i r: ol Co'/ie" .'ire, V?P-lf l'S*. (* ocl r3c*. ??j) :>.y 157*!. "'cIk-I r'-n, y,,"-.rtt 'c^oo1. of ?',Y. VIA. "A*.V-o'.< s n* * it T' c- 1` r. 1:; ~ K?'nt<: ri'r.f:'' s~d 1?75- (l*-lr'vo* Jo Ve f'.'.il v * :.v or. of a* si/;1 plove - 14) !.hl, ''olff sno *>ifs-.-ir.: ilvrt Sc'orl of . "rAir:1:/-, "Y, VS/., "ArVc-ftop loipcojre ?:v<e Lir.isj rii'r.ae r-r.d 107c Envir:.-*i :-:vt r*l ?.{r-:-f-rch 12, -110 - 122 . ^ ~ohl', *1] Ir CDtid 's, 1'olff, SellVoff: ilr-unt Sinai School. of !-*:* c`'n:-, **?,. VSA ''As Yosto* Content of 2js` n^corvitr^S In * +. z TV-;:M'.fr.c': mf* ri-oa. ?.c;*sl Sac. KeA; ?0;?2-37 * * * . : Svrrflc.vsl- Tnstiv.i:- of end .rT*ep?c*, V'SA. 'V.^tS/oo tne 7revcr.t*ra :v*.s-jras 7?r fil +0 - "*.ltv. of Ycrhws". (Shapir-r-V). i?75 ' * -* cr^s-M rf ?J. . *i* ? . *' /:*r*.. *"V>,*i ' rf 2- = * USA. rer^na! ;.:v~V& rervieo I1*?/fri Bor'nf*, C^ifcrrit - mv! rtliroif. -Aajvat * 4 . I Loririor an! Tih.lj J-'o-mt Serial School of Ke$ic5nt, 1?.', USA. ."la*-*3too Zrp-?Mie of r-rr'-'c oepa'r Yorkers Id th? US". Internal '.or.cl Conference. on Occapatlrn?! Health, Brighten, Upland. Srplealer 1575. > AIA-21 ?1. .Tic? ; Tc'-tl 3'n'-; Crhon1. of *':* '' r.r , irA. "C'. -nr'iiva i Ly on no of T-zcn C-* -v.^s rf Vo-V-erfi. I:i1.'*';)?.A 'c nil Confer'.:vcc on r* *.*..'1 r-.-jrl `)*p C.'O ?P. . Si Tcof. K.L.: Coro^e! Lr V-i^aA Ay of fc ~ !> I her? "JuM<c n??.;''. * -.*.* nf .Lv-^rc to Arlc - trs".' T'-j^ri of a "or* ''r.j Ciorp -f y.:-=-7ic f-- '>.<' Co- `iisricn of the Ii'L'oy, t-n Cor: ' r'\` _ for for.'.rl Aff-'i-rr, "f-olto ''f' 'y. '7 7 SeV* "fjn'r and "om^rd; Centre re rorfV ci; cr;-:?:vr.t Coo* nipii-Mr.' , "La Pollut'or. /.; ..cop'-aiir * W.-ijv y=r 7.'/.3*'ecJ.J ", Jounces d'Etv;J.- svr la Corf r* loyle TV'- r I r:` el 7 -, ??ris. Jvne 197.5* . .21 f.nVr.rtoKis research Co'vncil/Tochc*1e, Lnyl'-.d. Personal cor-nunication to A.A.Cross* "Investigation into levels of airborne asbestos dust in the London Underground, etc.", 1978. n. Jo: r*?-7Vinvtllr; Lenver, Colorado, USA, Tostor. ; vV. ?y - Cr-V:- rrr.he Heirs Emission 1?77* 2f. Vinton Laboratories, Surrey, Upland. "Asbestos in the Unfi'i^ro'r.c no enuse for el?.rn", 27.' "uffi.cy, 2.1., Terodo, Chapel-en-lc-Trith, Lc-rV. .-`.ire, In^lnni. Personal Corr'Siio*tion - Asbestos Content of *>r.-r fr'-drets frr.n Friction Materials, June i9$9 * ** t` , 28. Anderson, Dealer, KcCur.e, Sprys; Ford Motor Company, USA, "Asbestos Ihisalons from BraVe Jyruuropetar Tests", (F.ef, as 13) 29. Cilson, J.C.l fosner Director of Kedioal Kes6ereh Council AIA-21 T*>. "'rjbertos "-`.rco "r'eiior * > i nr.'*'1' et c. - Cr..-!'re?. -v.d f>fc-ty ^lide !>.". Ar.bc t \ " i r- r.v.-.'-nrch ">2vi ^ r;tr-? Ccri^o! "o:\niLtce ?.0. "or 1, T-V-rO-V./^ilon, Yf>r' -Mvr, Tr.J' *v,a. T^r. 1?70 (T/'t'-et y?v>.?< ',v. - i\%reh 1^77). ''"'-Tc *V_**:'jij v*`tti Ar*; rsi '.'C - Yrictiro rnJ Ar.ti-Tviction s", V3? - See item >0. t;7<-n^: .-.i"ori: 7.f.c! ' '.cs - "Aibri o.ftt j cr: f.nd Tr-e of As''C*os 'V ?rietion it*.* er: e'*, AIA/KA- Asbestos Tnforrsfon A* i- clotion of "orth /-'-fries?, '.VsMnyton I'SA. 'Triotion I-r.rJels VotJ: Practices Culr.;''* ?rict'!o:i !'e*.tri?l6 "tnrferds Institute. Poravus, Yov Jersey, V?A, fetober 1573, 1/ 1*C1 0 o t