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4,,. (\r^ Vul. |>r i' ?4 fniimnii fnu LtJ., |H'. Printed i CtMl IfiUia C/9*J SOME OBSERVATIONS ON ASBESTOSIS G. I.. Leatmart and J. T. Sanderson Dept, of Industrial Health, Kins's College, Newcastle-upon-Tyne Abstract- Asbestosis, which is a fatal occupational disease is still occurring JOyr after steps were taken to eliminate the disease. This is because of expansion of the industry, and especially of the insulating uses of asbestos. Nearly half the certified cases in the last two years occurred in insulators, w hose work is not covered by the regulations introduced JO yr a so. The work of a tagger in a building is described and it is concluded that mixing of mag* nesia,'asbestos plaster is the chief hazard. It is suggested that efforts should be made to find, and use. a substitute for asbestos fibre and that distribution of ready-mixed plaster should becor-: 1--1 **"--------- --- the Asbestos Industry Regulations and the Silicosis and Asbi ments) Scheme should be expanded to include the lagger and I Until such steps arc taken this essentially preventable dwe unnecessary death and suffering. INTRODUCTION Asbestosis is a fatal disease. It is due to a spreading fibrosis which not only restricts the expansion of the lungs but also interferes with uptake of oxygen into the blood. Eventually it causes death by slow suffocation. In a minority of patients a fatal cancer of the lung develops, and we seem to have been seeing this termination more frequently in recent years. The disease was first reported by Auribault, (1906) who ascribed to this cause the deaths of sixteen workers in an asbestos textile mill between 1890 and 189S the first British ease being that of Murray, (1907). By 1934 Wood and Gloyne were able to report their experience of 100 cases, mainly derived from the textile mills, in this country. Following the report of Mcrewether and Prict, (1930) legislation was introduced to protect the health of workers handling asbestos but this took a few years to become effective. This disease takes, on average, 20 yr to become manifest but if the measures taken in 1931-35 were fully effective, there should by now, some 30 yr li new cases occurring. In fact it has been my experience that the diseased increasingly frequently and the object of this paper is to examine this poss . to describe the changing pattern of incidence of the disease. Ji CERTIFICATIONS Figure I taken from Liathart, (1962) shows that certifications of asbestosis have not shown a satisfactory fait in recent yean and that they may even be increas ing. Like all certification figures they must be interpreted cautiously as there may *etl have been changes in diagnostic accuracy during these 30 yr; and there have been alterations of the law, especially the Pneumoconiosis and Byssinosis Benefit Scheme of 1952. which have brought more men into the compensation scheme, s 63 f 396081 u u i /: u 4 i* c 66 G. L. Leathart and J.T. Sanderson Fto. I. Certifications of Asbcstosis and Deaths, from 193! to 1939.'For the yean 1932-59-42 cases certified under the Pneumoconiosis and Byssinoslt Benefit Scheme have been added to the normal certifications (I*, 7 per year). Moreover the asbestos industry has expanded greatly during this period and there probably are more men exposed than there used to be. " THE ASBESTOS INDUSTRY In 1935 the asbestos industry employed 10,000 workers; in 195S there were 18,700 employees. Expansion ofthe industry is also reflected in increasing imports of asbestos, recorded in the annual reports of the Board of Trader whieh are repre* tented graphically in Fig. 2. Most of the cases of asbcstosis which are occurring nowadays started work in the industry before 1945. The further expansion of the industry since that date suggests that we may see many more cases in the future. Tabu 1. Asrotos products in sm OMvro KMooeM froto)*1930 1933 1938 1. Asbestos cement products 2. Packing, lasting, and Jointing 3. Brake and clutch linings 4. Other asbestos products (> 5. Asbestos textiles <*) f, Insuiaiing materials (e) 105,720 2070 22474 I4M00*. 461,700 7263^ : M&OT' 2243*- \' NUOOO* 22,117 -- 16,424 36400 (0) Mainly asbestos textiles (b) Excluding Ihow contained in 3 (c) Included under 2 * Approximate 396082 cf JI: ev i t * ` t * tic fc: F: as' I u v >.4 V r I c: la Some Oi" ^nations on A'bcstosi* MH1~J v*cjts u . morn. 67 9 if)/' I n n i c The first cases of asbestosis were derived from asbestos textile milts, but analysis cf the asbestos industry (based on the Board of Trade Censuses of Production) r.r rests that asbestos textiles have increased less than some other products (Table 1). 1: :> unfortunate that information given by the censuses is not very detailed. How* e-rr, it appears that the greatest actual increase has been in asbestos cement products, but the greatest percentage increase has been in.insulating materials,' - hich increased six*fold by weight, between 1933 and 1958. CERTIFICATIONS IN DIFFERENT JOBS Unhappily, growth of the insulating industry is also reflected in recent certificn* tirns of cases of asbestosis. The cases certified in 1960 and 1961 have been divided i-*:o groups derived from different occupations and are represented pictorially in F:;. 3*. It can be seen that 32 out of the 67 cases were employed on insulating or 2`bfstos spraying. The Asbestosis (Medical Arrangements) Scheme of 1931 is concerned with medical supervision of workers in textite mills and asbestos product factories i-d it is disturbing to find that in recent years the majority of cases of asbestosis -i\c been occurring in the insulating industry which this Scheme does not cover. Moreover it is quite likely that regular medical supervision of insulators would cal more cases than are at present coming to light through hospitals and chest c':nic$. I am indented to Da. J. W.*tmn*P)tcmio*u, of tha Ministry of Pension* and ***urinc, for the certification figure*. 396083 6S G. L. Li mii art and J. T. Sanoirson The incidence of a\hcMo>is among insulators is unknown. The total number c f men employed is certainly less than the 18,700 in the asbestos products industry and probahly is about 5000. In this part of the country rather fewer than 500 men arc A^QESTQSIS 1980 l ttftt posuna op wvu o *3 *o o *rt.ATr.. .r J UHi'cs ucrc -T1 uatics mtu uero ASKITOS < f1TTMC[j MAT t*C MAAMO WMil * I I li im oo Fig. 3. Cases of asbestosis certified during I960 and 1961 grouped according to occupation. engaged on this work, but I'has amongst them. It therefore appears that asbestosis is relatively common in insulators. In view of this it would seem justifiable to take a closer look at the insulating industry to see if steps can be taken to reduce the prevalence of asbestosis. THE WORK OF AN INSULATOR Insulators work in ships, power stations, factories and buildings, where they arc required to lag boilers and pipes. The material most commonly used for this b a plaster consisting of 85 per cent magnesia bonded with 15 per cent of amosite asbestos. It is used in the form of pipe-sections, slabs, and powder. Valves and flanges are covered with asbestos mattresses (containing the same powder) and occasionally pure asbesto sections (bonded with sodium silicate) may be used. The lagger fastens slabs or preformed sections round the boiler or pip with wire, then applies a coat of wet plaster by hand, and finishes off with a coat of waterproof cement. On board ship, w here temperatures are higher, the pipe sections are finished off with a covering of asbestos cloth made from chrysolite asbestos. The installation of a new heating system in a local hospital gave us the chance to watch the work in progress and to make a few measurements of dust concentra tion. The workers say that the mixing of powdered magnesia/asbestos plaster with water, and the stripping off of old lagging, are the dustiest processes. Mixing b done in a bucket, dust bin, or large box, depending on the amount required, and illustrated in Fig. 4. The mixing process takes 5-15 min and is repeated every 2-4 hr Usually the mixing is all done by one person, often by the apprentice who has just started work. Knowing that asbestosis is slow to develop one might suggest that it would be better if this dusty work were to be done by the elderly worker nearir? retirement. Often the work has to be done in confined spaces, such as between bulkheads tfl a ship, or in long ducts beneath the floor of a factory. Figure 5 shows a "lageer 396084 f i 'i n z i o o si \ r Fkj. 4. Air sampling by thermal precipitator during the mining of magnesia asbestos plaster with water. !. h 396085 TO medical examination by a member of The Pneumoconiosis Medical Panel, and cr.-,. powers the medical specialist to prohibit the employee from further work in cont^: with asbestos. In practice this scheme means examination at intervals not exceeding two years and the examination frequently, but not invariably, includes a chest radio graph. Men working in the insulating industry are not included within this schcn.c and, as things arc at present arranged, the lagger is denied the benefits of environ mental precautions at work and of periodic medical examination, but entitled to compensation'* when crippled hy asbestosis. It would be unfair to the industry u* omit to mention that some of the larger firms have a voluntary scheme for periodic medical examination which is entirely free to their employees. Such schemes arc costly and tend to be ineffective because they are voluntary, and because the employees fear exantination may lead to suspension from work. Now that so many of the certified cases of the disease arc occurring in laggers it would appear that stcp> should be taken to make such examinations a legal obligation by broadening the Medical Arrangements Scheme*; and the preventive ideals of the Asbestos Industry Regulations should also be applied to lagging. PREVENTION OF ASBESTOSIS^JN The principles upon which the^prewitWnSlJd automation, total enclosure, exhaust ventilation,^ respirators,*ire?WlI*knos (McLaughlin, 1953) but few of them can be applied to the job of the lagger. Substitution of an innocuous material for asbestos would seem to oiler the best solution, and, in fact, artificial rock wool and glass wool are being used in increasing amounts. Both are believed to be harmless to the lungs but our experience of them not very extensive. Unless it is bonded with resin, glass wool is unpleasant to work* with. The workers complain, not only of itching skin, but also of a "burning" sore throat and this suggests that bronchitis might be a late sequela. Total enclosure is obviously impossible but the mixing of magnesiafasbestos plaster with water might be done centrally, and automatically. The objections to this arc financial and based on the costs of distribution of ready-mixed plaster bat since the plaster docs not set (as cement does) and can be used days or weeks after mixing, delivery of a plaster slurry in bulk might be considered. Another possibility that might be considered is to make the plaster sticky before delivery, perhaps by the addition of a water soluble oil. Exhaust ventilation is clearly impracticable but forced ventilation of confined spaces on board ship should lower the dust concentration. Personal protection of the worker, in the form of some sort of dust mask is theoretically feasible but it must be remembered that lagging, like all plastering, is heavy work for which the worker needs to breathe ten or fifteen-thousand litres of air in a shi**t. The dust filter must be capable of passing such a large volume of air without becoming dogged. Firemasks are often found to be too hot for comfort and this objection carries particular weight in the ease of the lagger. His working conditions arc hot and humid a<thc pipes on which he is putting wet plaster are usually hot at the time (in order to dry After presentation of this paper the author was Informed that the T.U.C. and the Ministries concerned are at present engaged in discussions on how to achieve this. 396086 c 3 cs c c Ps u a o / h d fc r v a t c Some Observe! rut the plaster) and we have recorded as 89 *F (Tabic 2). ` T,J 71 temperatures as high Tami 2. IJanoe or cowucnrntmcnvt uotwa* twus ixriAiiNCio dcrino asxstos iacojnow a- NoamAL Working area Large bofler plant 12 ftx IS ft xj ft Large duct 10 ft x 10 ft Medium duct TftxOft SmaOduct SftxS ft the provision of dust masks is probably not an effective preventive measure. More, radical step s will have to be taken. - .. '-V. MU^NVk.. __ CONCLUSIONS;., and it is felt that steps should be taken to deal with this probiem^UOsersupervision^; of the laggcrs' health, perhaps by extension of theSilicosis ancLAsbestosis (Medical* Arrangements) Scheme, should help to focus the attention of'employerron this, hazard, and to define the extent of the problem* Prevention.^the:disease probably depends on substitution of an innocuous material for asbestos but something mighty be achieved by reducing the handling of dry asbestos plaster.* The provision of respirators is less likely to be effective, because the hot andhumid.conditions in which a lagger works add materially to the discomforts of wearing a respirator. The object of this communication is to reveal theJtazardtof the lagger's work to a aider audience in the hope that something furtherwill be done^both by the Indus**^. try and by the Health Services, to prevent him developing'afcrippling.ond fatal disease. Aeknowlex/gementt--l am grateful to Mrs. D. Wuohtman for drawing Figs* I, 2, 3 and 6, and to the Department of Photography in the University of Durham for Figs. 4 and 5. And I am especially indebted loDn.J. WatkinvPitchio*o for the help given by his Department and for the informa* lion used in the construction of Figs. I and 3. REFERENCES Avunuiar. M. (1906) BmU. /./. Trar^ (14th year), PaHa. p. 120-132. M. M. (1907) Report of Departmental Committee on Compensationfor Industrial Diseases. ( Fri,h-nee. Cd. 3496 It.M.S.O. (Lon.), p. I27-12S. - Mtnj> fnncrtii.my. 396087 72 C. L. LfftTttAT andJ. T.Sandcuo* Mmu wiima. F. R. A. and Pater. C. W. (l93OTR?R0rrw Effeetx of Adieuos Dmu on the i.,,r. ond Dust Suppression in the Asfr-sios Industry, Home Office. H.M.S.O. (l.ond.). 1 Ltatmut, G. L. IIW) Studies of PulmonaryFunction in Workers exposed to Asbestos. M \> Thesis. Camb. Unis. McLaIV.iii iv, A. 1. G. (1W). lusncet ii, 49 andJ04. DISCUSSION Da. F. P. G ai l (Sicbc Gorman. Chcssington, Surrey): What about the possibility and aJv, . tages of wearing a dust mask during the mixing of the asbestos plaster which takes about minutes of time ? Da. D. E. ItiCKisif (Occupational Hygiene Service. Slough): 1 would like to thank you for interesting paper. During recent years our Dr. Challen looked into this problem and we a:', concluded that mixing and stripping were the hazardous processes though we did not have opportunity to do dust counts. We did notice however, that even when mixing was done in if.-, open air it is often done in the bottom of an old oil drum and this meansthat the man doing i: f' mixing is bending down with his head in the dust cloud inside the drum. The point that I wov:j like to make is that we were shown figures of dust counts of up to 300 partielesfcin*. It is my oi view that the M.A.C. of 175 applies to particulate dust and that a figure of 30 particles/cm* wou'j be more realistic for fibrous particles. This would make the laggers work more dangerous th Dr. Leathart has implied. Ma. S. G. Luxon (H.M. Factory !nspectorate)rTherri*a legalrequirement,to take ait slept m protect these people and I hope to enlighten you when I speak because this may help. Da. J. S. McLintocv. n.c.*.: Normally when an industrial pulmonary diseue b accompanied by a typical radiological appearance, this X-ray picture is taken as a majorcriterion in diagnosis ^ and I think Dr. Leathart implied that this was the case in asbestosis. But f understand th.it asbestosis may now' be diagnosed for compensation before any X-ray changes can be seen. \WilJ "Dr. Leathart care to comment? Is it possible that this may be one of the reasons for the men* rise in "certification'* figures ? Mk. F. B. Ckossuv (I M F (Kynoch) Ltd.): Would the particle size range 5-50 p uscJ n Dr. Lcathart's experiments be within the respirable range? Paor. R. E. Last (Manchester University): Since it has been implied that mixing avbc-w plaster with water is the cause of asbestosis it is very important to know how much time is *r.*rt on this process. Can I ask how- long the mixing process takes and how frequently it is done dunr; the shift? Dk. SmiiHtks (Cape Asbestos Company): Dr. Leathart** excellent paper reminds me thai r have had previous occasions on which to differ a little. Firstly I am not as gloomy as he on Or question of incidence. The regulations promulgated In 1931 came into force in 1933. The hui incidence of the later thirties reflected the working conditions of the pre-1933 yean. There v as. he has shown, a drop in the number of new cases in the late forties and early fifties which relieve! the improved conditions after 1933. The rise in incidence in the latter half of the fifties reflects tv war-time working conditions when more people were employed on increased production at a trr when black-out and security were more vital than ventilation. A study of the number of yean exposure before diagnosis in a series of cases gives a trwr picture of progress. In the series reported hy the late Dr. Wyers, up to 1949 the average exposure' his cases was 10*5 years. In a series of cases from the same factory, ftilly investigated at Hamn*** smith Hospital in 1959, the average exposure was 14-J years. Thus in 10 yean the improvcmc-t was already evident. (Tabic I.) On the question of incidence of malignancy our experience differs from Dr. Leathart'*. TV picture in this country is also very different from that seen in South Africa, where I recently `J ` some most interesting material. There one saw many more cases of pleural involvement and plec'1* malignancy. The South Africans find our incidence of wrhal we may call parenchymatous ma -nancy quite astounding. Similarly the South African experience of peritoneal malignancy dill-' from ours. This will be the subject of a subsequent communication. These variations in man's reactions to asbestos stimulated me to consider thcdiffcrcnces betwr."' various types of asbestos. There are three main types of commercially important asbestos. Tl arc chryvotilc. crocidoliic and amositc. the two latter arc grouped as "amphibolc** asbestos. T`->` differ in gcologiciil formation, in chemical composition, in cryvtaiinc form, in fibre si/e .W 1 ausped, in their effect on man. I have tabulated a few of their differences and the result is interest ' 396088 Some Observation* on A^bnUwn 73 il B.* MJ C* o 3 IA Ug3 2 ~o *9* m~ --2-? j--|l 0eo 5 S^ZtZZ 3 e 1 `J*S2* eov 5o**Z >x I m s< o i i t wnrWM*^.i- fer --grtj*- 396089 74 O. L. Limhui ami J. T. JUsoi min Considerate m of the \ariatiom between typo of asbestos may well lead to better uik.':-. standirc of the nature of it* effect* on nun. I feel it is no (oncer cnouch to report that a man > ', been exps* vJ to asbestos. Wematt determine with which type or mixture of type* of asbestos man ha* worked. Pwor. R. C. Brownt: Can anbody in the audience tell ut why asbestos ix carcinogenic? Dr. Ci. L. I t xiiixrt: Hot of all it was suggested that a dust mask might be worn by then engaged on the mixing privets. I think this is a perfectly practical suggestion and I see no rea . why a mask should not he worn at this time. The time taken by the mixing process depends on amount being mixed hut on aserage it takes 3 -13 min and is repeated at intervals of 2-4 hovi 1 thank Dr. Ilickish for his interest and with regard to the M.A.C. for asbestos dust I do am feel qualified to comment. I am quite prepared to accept his figure of 30 particks.tm1 as a mur. reasonable M.A.C. for fibrous particles, and I agree that this means that the dust hazard is grcx<i than 1 had previously implied. I am grateful to Mr. Luxoo for hh contribution on the part that can be played by the Factor) Inspectorate. I agree that in the past the diagnosis of atbestosis has depended mainly on thcX*ray butthat, diagnosis is now occasionally being made before radiological abnormalities are apparent. Diagnou< depends on the demonstration of persistent erspitations-at-the King bases, and pulmonary fu^ctwr tests may also be some help. We do not know to what extent this may have influenced theCCrta cation figures. I was asked whether the particle size range that * measured is outside the ftipiriblifMga am sure that it b not. I agree that a spherical particle of 50 p diameter would drop like a stone h the fibrous particles of asbestos ure<very &ghtamd float< In the air much more rcadilyoYou.<l remember that fibres recovered from the human lung have measured up to ?n0 p in kugttMfg: 1 am very grateful to Dr. Smither for coming here and making such an interesting contributi > to the discussion. He said that he had crossed swords with me before but this is not strictly tr.c Our relationship has always been most friendly and 1 hope that it always will be so. Today. I:. grateful to him for the information he has given us and for the interest he has shown in my par-- GO --I CD CO .X) CD c_n co 396090