Document YXooQaZKjaBj25zyXkRbOB0K

ASBESTOS INTERNATIONAL ASSOCIATION (Limited by Guarantee) 68 GLOUCESTER PLACE, LONDON WiH 3HL MEMORANDUM ` TO:' Member Associations Medical Advisory Panel Executive Committee FROM: Director-General * A1A/5/FIB 10 June 1981 t Cape Blue Asbestos Please find attached a well referenced paper on Cape Blue Asbestos which Mr. Baunach has asked me to circulate. PLAINTIFF'S EXHIBIT Sir Neville Stack CAP CO JEN 0013170 File 13.1.B REVISED DRAFT At ay^/pns --h . PREHATURE-PREJUDICE AGAINST CAPE BLUE ASBESTOS ' ' r' ' '' ' i.' . ` t..> CV*.' *- - *" -. ' .. o->.j n. 1. For morB than 20 years, .attention .has bean focused all over i-j -:r 1 '' . . the world on potential, health hazards associated with asbestos -- and particularly Cape blue asbestos. r..U,- : } i i 2. Since the 1972 Lyon Conference,- it has .repeatedly been stressed at almost every international scientific meeting on health hazards of asbestos that there is no significant difference between commercial asbestos fibre types in relation to the incidence of asbestosis and bronchogenic carcinoma. (1 - 4) " -.,.v or. -.:1V . 3.1. It is only in relation to mesothelioma that the United Kingdom and subsequently some other countries such as Denmark, Holland, Ireland, Japan, Norway and Sweden assumed a higher risk for crocidolite. Howeverj according to current scientific knowledge therB is no conclusive evidence for this assumption. (5-8)- .Therefore, the question arises, whether there is any justification for discriminatory legislation or control measures as initiated in Britain in 1969. , 3.2. It would appear that the proved number of primary diffuse mesothelioma cases up to 1977 from all over the world was confined to roughly 5 000 as indicated by Prof. J.C. McDonald at the Johannesburg Asbestos Symposium in October iq77 to in\ CAP CO JEN 0013171 Page 2 3.2.1. In general, Prof. McDonald'8 paper did not give any es sentially additional information to that presented at the Brighton Conference in 1975, except for quoting * * and over-Bmphasising the incidence of the disease in t :. personnel employed during World War II in two gas-mask factories, one in England and the other in CanadB, with high rates of cases at "relatively low exposure". However, during discussions at the Conferencefit was strongly implied that those exposures were not as low as claimed by Prof. McDonald, but were in fact very high. Crocidolite is dustier to handle than other asbestos types and the packing in the gas masks of loosely bound"-pads gavs rise to higher exposures. It is noteworthy that Australian crocidolite was used in the gas mask factories and it is possible that the risk for this fibre is at variance with that of Cape crocidolite^ ". 3.2.2. 5 000 cases were'reported throughout the world over a period of 25 years. By comparison, the annual in cidence of deaths from lung cancer among males in the UK amounts to over 25 000 (10$6)(12) end in the USA to more than 50 000 cases (5^). According to Prof. Selikoff at the Dohannesburg Asbestos Symposium (13) and subsequently confirmed by Dr R. Saracci (for the IARC/bJHO) at the Washington Conference, December 1977, CAPCO JEN 0013172 Page 3 lung cancer in asbestos workers is in fact s far r- * '; * v ./r.-ti.--* i-' -* : - bigger risk than mesothelioma, mainly in conjunction ... . ; rrr..:.s.n-riuni 1 "i with smoking. ' 3.2.3. Where employment records were available, 66% of : ' 7" it r.'-'y if *-r mesothelioma~case3 could be attributed to asbestos ^ ^ y/.*. .) u -it ' * ' i *' .*1 wiv. exposure.*- ..(14) There was no asbestos exposure in 34^.of thB cases of the FlcDonald survey. It seems " strangB that no attention has been paid to this phenomenon, although for several years it had been .known that there are other causes for mesothelioma. 7 (15) Tor instance, in two villages of Eastern - Anatolia,' Turkey"*1 pleural and peritoneal mesothelioma-, 'were of higher incidence than reported anywhere else ! ' in the world. All soil samples were free of asbestos fibres and zeolite minerals were shown to be the causative agents of these mesothelioma cases in Turkey. (16) There are several reports from India dealing with mesothelioma caused by bagassosis. 3.2.4. The ecology of mesothelioma,is still unknown and there < g . ,, *.*... . >....vJ. Ji . *. * is as yet no reliable method of early diagnosis of the. disease. (17) The indictment of blue asbestos came # ** mainly from South Africa where it was considered to be thB sole causal agent of mesothelioma, but npt so in . . other countries.. - 3i2i5.`" Hammond and Selikoff report a high -incidence of cases CAP CO JEN 0013173 Page 4 among insulation workers who, they emphasise repeated ly, were exposed largely to chrysotile and amosite. (18) Apparently, crocidolite was not used in the United States for `insulation purposes. The largest U.S. asbestos manufacturer never used crocidolite for insulation at any time, employing it only in two product lines, namely AC pipes and packings. (19) The whole concept of asbestos exposure was queried at the Dohannesburg and Washington Conferences by Dr. George Wright who claimed that it was intellectual arrogance to speak about asbestos exposure "being characterised solely by the number of fibres of varying sizes present in the environment of the working place. In the real world of those exposed at working places nothing could be further from the facts." No people anywhere in asbestos mining, milling and/or manufacturing were exposed to asbestos only. There were various risks other than asbestos which, except for the synergistic effects of cigarette smoking, had so far been completely ignored. (20) By modern standards, past exposure was incredibly high, definitely in the hundreds, peak periods in the thousands. (F/cc)(21-24) Most exposure estimates were vague to the extent that one should not even bother to consider them. (25) Except in the case of asbestos mining, it is unusual for workers to be exposed to one type of asbestos only in the course of a lifetime, and except for very feu and fairly small applications, bluB asbestos fibres are never used on their own but mainly in CAP CO JEN 0013174 Page 5. relatively small quantities as ^supplementary fibres with fibrous mixes of the asbestos-cement industry. Although blue asbestos has been used in that industry ell over the world for more then half a century, relatively feu confirmed cases of mesothelioma have been reported from these factories. 7. Profs. A. and D.C. McDonald maintained that mining environments may uell be free from carcinogens in the kind found in factories, ports and industrial cities. Moreover, fibre as produced at mills almost certainly differs in length and diameter from that used in subsequent industrial processing. (26) B. Many observers completely ignore the fact that, in the earlier reports of Wagner, there uere only a feu cases of occupational exposure, the balance being environmental uhere other pollutants, tubercular scarring, climatic conditions, ethnic factors, etc. could have been contributory factors in the' development of the disease. 9. In October 1977, the South African Asbestos Tumour Reference Panel had, according to Prof. Webster, 712 cases on its register, uhich included all recorded S.A. cases of mesothelioma sincB 1956. (27) 9.1. Occupational exposure had been established in 420 cases only but in 10j6 of these there uere no firm indications of asbestos exposure. CAPCO JEN 0013175 Page 6 9.2. Actual mining exposure accounted for 33$ of these cases, W, or roughly 20$ of the .to'tal. There were another 20$ environmental cases, mainly from the northwestern Cape, #. 20$ non-mining industrials and 30$ with no knowledge of any exposure or details of occupational history. 10. At the 1978 New York Conference, it was emphasised that: 10.1. Respirable asbestos fibres are ubiquitous anywhere in the world. Many short fibres found in human lungs may have nothing to do with commercial fibres, but may have been completely untreated natural fibres inhaled from the ambient atmosphere. 10.2. There must be an exposure level which can be tolerated other wise we would have had many more cases of mesothelioma apart from many more asbestosis and lung cancer occurrences from primary production (mines and mills). 10.3. In British ships, extensive use was made of blue asbestos in spraying decks end bulkheads for several decades. Thousands of people must have lived constantly under these conditions. Hare than 1,5 million men have served in the British Navy between World War I and now. This suggests that there does exist a level of exposure which is safe. Unless respirable blue asbestos fibre is released through poorly controlled stripping or demolition, there appears to be no risk. (28) CAPCO JEN 0013176 Page 7 11. CONCLUSIONS The main arguments against crocidolite mars and are still being taken from initial SA investigations of limited occupational end mainly environmental exposures, without any details on the actual extent of dust exposure and dust properties. Elsewhere in the world, industrial asbestos exposures were mixed and in most cases Btftremely heavy. Such conditions ceased to exist long ago. According- to two recent independent surveys of published literature on epidemiological"studies, animal experiments and toxicological t tests, there is no conclusive scientific evidence justifying any differentiation between the potential health hazards of various asbestos fibres. (7-8) Moreover, there are still many serious gaps in the medical knowledge of asbestos-related diseases, apart from the fact that various medical evaluations of past conditions many years ago are not internationally comparable by reason of differences in diagnosis and incompatibility of statistical information and documentation.- Present knowledge of the mechanism of the cause of cancer is incom plete and the absolute carcinogenicity of the various asbestos fibres is still unknown. According to Langer, of the Mount Sinai Medical Centre N.Y., the present emphasis on crocidoli-t^ is premature. (29) CL. -JU F. AUNACH CAPCO JEN 0013177 REFERENCES 1. UagnBr, 3.C. 2. Webster,' I. 3. Sluis-Cremer, G.K. 4. Iruig, L. 5. Kleinfeld, M. G. Wagner, D.C. 7. Davis, D.M.G.* 8. Beck, E.G.** 9. McDonald, D.C. ID. Me Donald,.D.C. Me Donald, A. 11. Wright, G. 12. Gear, D.H. 13. Selikoff, I. 14. McDonald, D.C. 15. Gluckman, D. 16. Baris, V.L. 17. Elmes, P.C. ' IB. Selikoff, I. 19. Selikoff, I. Hammond, E.C. 20. Wright, G. 21. Du Toit, R.S.D. 22. Robock, K. 23. ' Wiles, F. 24. Sluis-Cremer, G.K. 25. Elmes, P.C. NY Acad. Sc Vol 132 (1965) IARC No. 8 p. 197/8 Proceedings Dohannesburg Asbestos Symposium (DAS) p. 54 (4) DAS 60 1 D.Occ.ried. 15, 1973 p.299 DAS 110 Evidence for variations in the patho genic affects of the different forms of commercially used asbestos - A re view of the literature. (Still to be published) Summary and Conclusions of an appraisal of literature on the question whether crocidolite must bs considered more dangerous than chrysotile. (Still to be published) DAS p.67 - 79 Preventative Med. 6, p.426 - 440 DAS p.81 Proceedings Dhb Pneumoconiosis Conf. ' (DPC) p.213 DAS p.91 DAS p.67 DPt p.143 Thorax 1978, 33 184; NY Acad. Sc Vol 330 p.423 (1979) DAS p.16 DAS p.80 DPC p.184 DAS p.96 DAS p.45 DAS p.27 DAS p.104 DAS p.51 DAS pp.15 and 105 * Institute of Occupational Medicine, Edinburgh, UK ** Hygiene Institute of the Medical Centre for Ecology, Dustus-Liebig University Giessen fFGRl CAPCO JEN 0013178 26. McDonald, D.C McDonald, A. 27. Webster, I.. 28. Wright, G. 29. Langer, A.M. Mackler, A.D. Pooley, F.D. 2- - Prev. Mad. 6, 1977 p.440 DAS p.79 NY Acad. Sc Vol 330, 384/5 (1979) Eviron. Health Persp. 9, 1974 (4076) P. 79 < ooooOoooo F8/MS Dohannesburg 6th May 19B1 CAPCO JEN 0013179