Document gDonjdbQqNrJ9pXRjZB8ap9BQ

FILE NAME: Sprayed Asbestos (SPRA) DATE: 1965 Dec 31 DOC#: SPRA021 DOCUMENT DESCRIPTION: Medical Journal Article - Asbestosis in Great Britain ANNALS OF THE NEW YORK ACADEMY OF SCIENCES Volume 132, Art. 1 P ages 1-766 December 31,1965 Editor H arold E. Whipple Associate Editor P aul E. van Reyen BIOLOGICAL EFFECTS OF ASBESTOS* Conference Cochairmen I. J. Selikoff J. Churg CONTENTS Preface. By E unice T homas M iner .................... Opening Remarks. By Irving J. Sei.ikoff . ' Man and Asbestos. By J. C. Gilson. ............ . . .. 5 7 .......... 9 section I. Asbestos M aterials in M odern Technology The Geology, Occurrences, and Maior Uses of Asbestos. The Physical and Molecular Structure of Asbestos. By R ichard G . Chemical Studies of Asbestos. By J. S. Harington ..................... ' 23 ^ - fasstitssatxtsrinT""e' * "te; Section ,1. Unnc ano M .ne. ai. Matte. , 8,8 S m toaU^MadeDuring1W ^ lt ^ AGEL" 64 s c h m i d t ....................... . p , d T c W agner and J. W. Asbestos D ust Deposition and Retention in Ra . H ............ 77 Skidmore............. of Fibers: Importance of Small 87 EXPp S s ^ / p . T holt, J M iu T and D. K. Young. ^ _ Electron-Microscope Studies of Asbestosis in M an and Anima s. y 98 Rheunmtoid Factor in Serum of Exposed to Asbestos. By B. ^ PERNIS, E .C . VIGL1ANI AND I. J. SELIKOFF . .. m Discussion. . ....................... .................. Section i n . H oman Ex- onoi. e to Asbestos, . noosteixc Potoc. tions ^ Asbestosis in Gre.t Britain. B, J. C. 1McVittie -- ^ ^ st>Mi The Occurrence of ^ abef 0QECKC A N D ^ U Hammond . MOX worhers in h. U n it. .....................139 S,c u f .'," n A -b e ,o s , - Asbestos M * * 3' Discussion. ' This series of papers is the resultof a ^"ference^entiOctober^' 20/and 21, Asbestos held by The New York^ mg H!ooi92-01 from the National Institutes 1964 and supported in part by grant No. cm of Health, Bethesda, Md. S ectjon IIF. H u m a n E xposure to A s b e s i o s : I n d u m k i a i . I W ui .a i i o n s ASBESTOSIS IN GREAT BRITAIN J. C. McVittie M inistry of Pensions and National Insurance, London, England Our knowledge of asbestosis dates from a post-mortem examination cairied out at the Charing Cross Hospital, London, 64 years ago. The findings of that post-mortem examination were given by Montague Murray' in evi dence before a Departmental Committee on Compensation for Industrial Diseases in 1906. He gave a good description of the morbid anatomy of pulmonary asbestosis and he produced photographs taken from specimens showing spicules of asbestos in the lungs of his young patient who died after 10 years exposure to cardroom dust. Eighteen years were to elapse before another post-mortem examination again directed attention to the possibility that silicates may cause extensive pulmonary fibrosis. In the interval interest was concentrated on what was regarded as the mote im portant and widespread risk associated with dusts containing fiee silica. The second case was reported by Cooke* in 1924, the first to appeal in Eng lish medical literature. His case is frequently associated with the dis covery of "curious bodies" but what Cooke demonstrated in the lungs of a young tuberculous female textile worker were actual particles of asbestos fibers and dust, and he always insisted that proof of the diagnosis did not include the presence of "curious bodies." Then suddenly, between 1927 and 1931, a whole new literature relating to asbestos appeared in Britain. The clinical picture of pulmonary asbes tosis was described by Oliver,' and the clinical and X-ray findings b\ Seiler,4 Burton Wood,'' and Ellman." Stuart McDonald7 described the his tology of pulmonary asbestosis, and referred to certain highly charactetistic yellowish brown bodies abundant in all sections. He advanced the hypothesis that the bodies were portions of asbestos fibers in the process of alteration. Stewart" described how the characteristic bodies could be detected immediately by making a lung "squeeze." Unfortunately he de scribed them as "asbestosis" bodies. Later Roodhouse Gloyne" suggested that "asbestos" bodies would be a better name. In the new literature the report by Merewether and Price"1 in 1930 was outstanding. The reporgave their conclusions and recommendations following an extenshe i n s tigation of workers and of conditions on the manufacturing side of thasbestos industry and was important on a number of counts. On the mem cal side the investigation established the occupational cause of asbestosiMerewether found that one in four of the sample of 363 workers examine, had evidence of pulmonary fibrosis attributable to asbestos dust and r calculated that on the sample, one in eight of all workers in the lnciu>t'| would be found to have evidence of fibrosis. It was made dear that t ' 128 strial P opulations McVittie: Asbestosis in Great Britain 129 TAIN principal safeguard against the ill effects of asbestos dust in the lungs was to be found in improved ventilation and dust suppression, and a number I 'wndon, England ef recommendations were made. - The results of the report were also important. Under section 79 of the I Factory and Workshops Act 1901 the Secretary of State issued a certificate rtem examination car to the effect that "the manipulation of asbestos and the manufacture and f ears ago. The findings n pair of articles composed wholly or partly of asbestos and processes in SL tague Murray1in t\i- cidental thereto are dangerous." The section in the Workmen's Compen- isation for Industrial aation Act of 1925, which provided for the application of that Act to work e morbid anatomy of men suffering from silicosis was extended to certain processes involving T taken from specimens exposure to asbestos dust," and in 1931 asbestosis became a compensatable ung patient who died disease. Compensation cover was fairly wide and the compensatable dis years were to elapse ease was defined as "fibrosis of the lungs due to asbestos dust or that icted attention to the disease accompanied by tuberculosis." Medical Boards of specially qualified >nary fibrosis. In the medical practitioners were appointed to make the medical examinations irded as the more im- and give the medical certificates, initial and periodical examinations of lontaining free silica, workers in certain scheduled processes in the industry were instituted, and irst to appear in Eng- the standard of physique required on initial examination was prescribed.1" xciated with the dil Special regulations which defined asbestos as "any fibrous silicate," lay if ated in the lungs of a down specific instructions as to exhaust ventilation, the prevention of dust %- particles of asbestos gaining access to the atmosphex-e of workrooms, the damping of floors and the diagnosis did not benches, the cleanliness of floors and plants, the stox-age of asbestos, and % the employment of young persons. The regulations1'1came into force with iw literature relating general application on March 1, 1932. of pulmonary ashesd X-ray findings by Case finding in Gi-eat Britain then has arisen mainly in two ways -- from the statutory periodical examinations carried out in cei-tain high-risk oc I Id7 described the hi- cupations in the industry, and from examinations following applications xin highly character- for compensation under the Wox-kmen's Compensation Acts and claims for ns. He advanced the disablement and death benefit under the Industrial Injuries Act,14 which fibers in the process superseded the Workmen's Compensation Act of 1948. istic bodies could be Under the Industrial Injuries Act the words silicosis and asbestosis Unfortunately he de were dropped and the comprehensive tex-m pneumoconiosis was introduced. le Gloyne" suggested Pneumoconiosis was defined in the Act as "fibrosis of the lungs due to le new literature the silica dust, asbestos dust or other d u st.. . . " The Act provided that the standing. The report effects of tuberculosis (pulmonary) in a person suffering fi-om pneumo ? an extensive inves- coniosis were to be treated as the effects of the pneumoconiosis. Cover was acturing side of tin- provided for all the main occupations in the industi-y: counts. On the medi- (a) the working or handling of asbestos or any admixture of asbestos; Icause of asbestosis. (b) the manufacture or repair of asbestos textiles or other articles con >3 workers examined taining or composed of asbestos; sbestos dust and hi (c) the cleaning of any machinei-y or plant used in any of the foi-egoing kers in the industry operations and of any chambers, fixtures and appliances for the made clear that the collection of asbestos dust; 130 Annals New York Academy of Sciences (d) substantial exposure to the dust arising from any of the foregoing operations. The diagnosis and disablement questions arising on claims for disable ment benefit under the Industrial Injuries Act are decided by the Pneu moconiosis Medical Panels of the Ministry of Pensions and National Insurance. The Panels also advise Insurance Officers on death claims. Post mortem examinations are carried out in the vast majority of cases and the lungs are always examined by two members of the Panel; thus in a number of cases not seen in life the diagnosis of asbestosis has been made post-mortem. A number of eases have also been found following examina tions under a special benefit scheme for older workers who were time-barred for compensation under the Workmen's Compensation Acts. The Panels also carry out the periodical medical examinations at the prescribed interval of two years. These different kinds of examination provide the only source of information about the prevalence of asbestosis in the country as a whole. Between 1931 and December, 1963,748 cases of asbestosis were diagnosed in life under the Workmen's Compensation Act and Industrial Injuries Act. Table 1 shows the number of cases diagnosed each year under the In dustrial Injuries Act. It shows that the number of new cases is increasing. The average of 45 for the last five years suggests that the incidence rate may be at least five per thousand exposed. Four of the Ministry's Pneumoconiosis Medical Panels account for the T able 1 N umber of N ew Cases of A sbestosis Diagnosed in L ife UNDER THE INDUSTRIAL INJURIES ACT, 1948 1950 (9 months) 17* 1951 17 1952 15 1953 23 1954 31 1955 48 1956 31 1957 56 1958 27 1959 37 1960 29 1961 43 1962 , 52 1963 67 Total 494 Detailed statistics o cases under the Industrial I n j u r i e s Act were not maintained until April 1950. * f McVittie: Asbestosis in Great Britain 131 Table 2 N ew Cases of A sbestosis 1955 -6 3 A nalyzed by P rincipal Occupation* Principal occupation Opening, disintegrating Insulating Laggers Sprayers Mattress makers Others Weaving Carding, spinning, etc. Slab and pipe making Brake lining Miscellaneous Total Grand total No. % 41 16.6 72 ) 13 \ 41.0 5 ( 12 / 16 | 21.5 37 20 8.1 4 1.6 27 11.0 247 At four Panels--London, Manchester, Newcastle, Sheffield. majority (63 per cent) of asbestosis cases. They are also the Panels mainly concerned with periodical medical examinations. In the nine-year period 1955-19G3 these Panels diagnosed 247 fresh cases of asbestosis including 34 female workers. They have been grouped according to the processes in which each was mainly employed and with similar processes grouped to gether. Table 2 shows the cases analyzed by principal occupation. It shows that the insulating section of the industry gave rise to 41 per cent of the total. The occupations of opening etc., carding and spinning, and the miscellane ous group which includes maintenance men were important causes of asbestosis, Table 3 shows whether diagnosis was the result of initial or periodical examination, or the result of a claim. Well over half the cases resulted from direct claims, and the majority of these (60 per cent) were from the insulating section of the industry. 132 Annals New York Academy of Sciences ' Table 3 N ew Cases of A sbestosis D iagnosed 1 9 5 5 - 1963* Principal occupation Diagnosis resulted from Initial or periodical exam. Claim to benefit Total Opening, disintegrating 24 17 41 Insulating Laggers 3 69 72 Sprayers - 13 13 Mattress makers 5 - 5 Others 7 5 12 Weaving 13 3 16 Carding, spinning, etc. 29 8 37 Slab and pipe making 8 12 20 Brake lining 2 2 4 Miscellaneous 13 14 27 I - Total 104 143 247 At four Panels--London, Manchester, Newcastle, Sheffield. Table 4 shows the cases analyzed by principal occupation and date of entry into the industry. The year 1933 was chosen because it was considered that by that date the regulations regarding ventilation and dust control were effective. It is recognized, however, that there were enormous dif ficulties in this regard during the war years. The majority (66 per cent) of the group entered the industry in 1933 or after. Table 5 shows the average exposure and the range of exposure in the principal occupations. The figures of average exposures in opening, and disintegrating and weaving are an impi-ovement on Merewether's figures for these occupations in 1930, but there is no room for complacency. Since 1933 the disease has been produced over short exposures. In practically every principal occupation asbestosis has developed following exposures of under 10 years. It is still developing. McVittie: Asbestosis in Great Britain 133 Table 4 N ew Cases of A sbestosis Diagnosed 1955 - 1963* A nalyzed by Date of E ntry into I ndustry ''irtinm 'iniir*11 ~ inf r n-irr:iittrir"X ftT r 'rJ`Tr i' '****' Entered Entered Principal occupation industry industry Total before 1933 1933 or after Opening, disintegrating Insulating Laggers Sprayers Mattress makers Others Weaving Carding, spinning etc. Slab and pipe making Brake lining Miscellaneous Total 3 41 1 2 3 6 10 3 3 10 82 (33%) 38 31 12 3 9 10 27 17 1 17 165 (67%) 41 72 13 5 12 16 37 20 4 27 247 (100%) isures. In practical!) Mowing exposures of At four Panels--London, Manchester, Newcastle, Sheffield. Table 6 shows an analysis by some of the principal occupations and date 'f entry into the industry after 1950 -- well after war conditions applied. Two of the insulating workers who entered in 1956 had only four years exposure. The sprayer who entered in 1953 had seven years exposure. The worker who entered carding and spinning in 1952 had five and one half years exposure. One of the sprayers who entered in 1951 and had nine years exposure has since died and asbestosis was confirmed at post-mortem. Scrutiny of the material suggests that age at entry into the industry was not a factor in the development of asbestosis. At periodic and other examinations the facts about duration of exposure and dates of exposure fan be elicited, but these examinations have not so far provided the means relating working conditions as measured by dust counts, to development the disease. The tables, and the knowledge of the processes involved in 134 Annals New York Academy of Sciences ' Table 5 N ew Cases of A sbestosis D iagnosed 1955 - 1963* (W orkers W ho E ntered the I ndustry in 1933 or A fter) Principal occupation Opening, disintegrating Insulating Laggers Sprayers Mattress makers Others Weaving Carding, spinning, etc. Slab and pipe making Brake lining Miscellaneous Average exposure in years 14 26 8.3 11 13 15 16 16 14 16 Range of exposure in years 4-20 8-44 3-12 5-22 9-27' 9-23 6-27 5-30 12-16 4-26 *At lour Panels--London, Manchester, Newcastle, Sheffield. the principal occupations suggest that development of the disease was re lated to dustiness of the job. Scrutiny of the working histories suggests that "range" of exposure depended on, for instance, whether raw material was freely handled, whether laggers and their laborers made mattresses on the site and broke down old asbestos lagging, and whether high speed cutting and sawing were carried- out in the sectional departments. Diagnostic Criteria Diagnosis was made on adequate exposure to asbestos dust plus two positive findings from the following-- presence of basal rales, finger club bing, radiological appearances and pulmonary function studies. Experience has shown that in some occupations recent exposure of three to four years is adequate, and this may be related to type of asbestos. Generally speaking, however, something like eight years exposure is re quired. On the other hand, very short past exposures 20 years ago are also adequate. McVittie: Asbestosis in Great Britain T able 6 N ew Cases of A sbestosis Diagnosed 1955 - 1963* A nalyzed by P rincipal Occupation and Date of E ntry into th e I ndustry after 1.M) principal occupation Year worker entered industry 135 Total Opening, disintegrating Insulating Sprayers Mattress m akers. Weaving Carding, spinning, etc. Slab and pipe making Total i 18 At four P an els--London, Manchester, N ew castle, Sheffield. Characteristic pcrsistent^ackling rales at'the bases were very commonly present Finger clubbingrthough not so common as basal ra es, was no in 35 per cent of the total, This finding, however, was subject to inter and intra observer error. , , , filrn,, The radiological appearances were very variable. A large numbei of fi showed the changes characteristic of interstitial fibrosis or pleural thickening, or both. A honeycomb appearance just above the d ; Phra^ ' a "ground glass" appearance made up of linear markings and small disciete opacities in the lower lobes, obliteration of the costo phrenic angle, shaggy heart shadow, and thickening of the interlobar septae were common - ings. Calcified plaques were also fairly common and " jc e seen ma nly the films of insulation workers. The Pneumoconiosis Medical Panel >con sider that bilateral calcified pleural plaques are almost diagnostic of as bestosis. The absolute symmetry in many cases and the slow piogiess can hardly be explained except on the basis of occupation. The Pneumoconiosis Medical Panels had found that worket- w , t h ^ - be.to.is had little tendency to asthma and other forms of airw ay otahuc tion but that they did not do a stepping test well The pa heog asbestosis - the small firm lung that stands up on the able, tha cut w t a clean edge, that shows parenchymal fibrosis without significant pleu al 136 Annals New York Academy of Sciences thickening, or shows marked pleural thickening without or with very slight macroscopic parenchymal fibrosis but with extensive microscopic fibrosis suggested that a useful diagnostic aid and a much better assessment of disablement would be provided by using multiple tests. Since 1960 the Panels have referred asbestos workers to special centers for full investi gation of lung function. The tests have shown a highly characteristic and consistent combination of changes, e.g. small inspiratory capacity, M.B.C. well maintained for lung volume, high F.E.V.%V.C., reduced diffusing capacity, and loss of compliance. These are specific to a small group of diseases, of which asbestosis is one. The disablement at the date of diagnosis was assessed as slight in 140 cases, moderate in 81 and severe in 26. Two cases were complicated by active tuberculosis at the date of diagnosis, two by pleural tumor and two by carcinoma of the lung. Follow Up Of this series of 247 cases 59 have died. The average age at death from all causes was 57 years. One death was not reported to the Pneumoconiosis Medical Panel and in one other case there was no post-mortem examination. The causes of death in the remaining 57 were as follows: Asbestosis (cor pulmonale) Asbestosis + acute pulmonary infection Cancer of lung Mesothelioma of pleura Mesothelioma of peritoneum Other cancers Coronary artery disease Other cardiovascular conditions Acute intestinal obstruction Acute meningitis Mesenteric thrombosis 8 9 40 per cent 1 3 5 5 1 1 1 In three cases the diagnosis of asbestosis was not confirmed post-mortem. In one with a history of 12-years exposure to dust in coal mines and an adequate exposure to asbestos dust, the slight radiological changes were due to coal miners' pneumoconiosis. In two cases the diagnosis of asbestosis during life was based mainly on a low diffusing capacity. Post-mortem examination showed only gross emphysema. Excluding these cases the average age at death of those who died from asbestosis was 57. The average age at death of those who died from cancer of the lung or pleura was 55 and the average age of those who died from other causes was 59. These findings are similar to those in 138 consecutive post-mortems on asbestos workers in the area on the London Panel. The average age at death from -Ti xt',; McVittie: Asbestosis in Great Britain 137 ft fti| causes in the London group of 106 males was 57 and of 32 females 58. f he average age at death of the males who died of asbestosis or asbestosis ,|tis infection was 56 and of females 59. The average age at death of males & who died from lung cancer was 57 and of females 59. fr Under the National Insurance (Industrial Injuries) (Prescribed Dis- i: f-ases) Regulations, sequelae of prescribed diseases are treated as prescribed diseases. The Pneumoconiosis Medical Panels accept lung cancer as a se quela of asbestosis. In view of the abnormally high prevalence of lung cancers associated with asbestosis the risk of including lung cancers due to other causes has been accepted and this attitude seems not unreasonable. In the 21 cases who died of lung cancer in the 1955/63 series the average interval between first exposure and death from cancer was 27 years. There was only one in which the period was less than 15 years. This worker entered the industry at the age of 59 and was exposed to asbestos dust for *ix years. There was very slight asbestosis post-mortem. Was this an in dustrial cancer? We would appreciate the views of the Conference on this problem. '' In addition to the figures of death from lung cancer, four of the survivors in the series are at present permanently incapacitated by asbestosis and pleural effusion. In two, lung cancer has been diagnosed, and in the other two mesothelioma of pleura is suspected. Seven other survivors are per r manently incapacitated by asbestosis and "bronchitis," and one is per manently incapacitated by asbestosis and tuberculosis. Scrutiny of the benefit history sheets (giving certified cause of incapacity) of the other survivors, shows that asbestotics are frequently incapacitated for long periods by "bronchitis" and "chest infection." However, a small number have reached retiring age without severe disablement and 27 have had no recorded chest illness since 1955. Initial and Periodical Examinations Against this background of the effects of asbestos dust the role of initial and periodical medical examinations of workers must be considered. Our ft Pneumoconiosis Medical Panels consider that these examinations of as- !>estos workers are the most worth while of all. No doubt the workers are happier when they see that they are being kept under observation by the Panel doctors. Regular visits to factories afford Panel doctors opportunities to meet factory doctors and to study the processes at first hand. Asbestosis is the most difficult of the pneumoconioses to diagnose and periodical exam inations provide experience in film reading and in the clinical aspects of the disease. In this regard the initial X-ray and lung function tests carried out when the worker enters the industry can be used as controls. May these examinations, however, give rise in the industry to a false sense of security <>nthe idea that the doctors have everything under control? What evidence !/ r { j '"t t 4 138 Annals New York Academy of Sciences is there that periodical tsz** for employment m the mdustiy. e q whether the employment is Mutable for t h e ^ r Pneu- b?^ In our experience ^ ^ jn very appreciable improvements in wor mg some sections of the industry by some can do. Let us remember the ansmei am some can do, others rn,n `given by Merewether re was sufficient to 30 years ago. When asked ^ eth" ..Yes, if she lives long enough." cause asbestosis in a young gnl, he itpnea, , References and Index. : 127. . 9.147 2. Cooke, W .E . 1924. Brit. Me ` 3. Oliver, T. 1927. J . In d u * .KyK. 4. Seiler, H. E. 1928. B rit. Med. J- 2 982. 5 BURTON WOOD, W. 1928. Tubercle. 10. 3o3. 6. ELLMAN,P. 1930. Proc Roy. 7. McDonald.S tuart. 192k B - ^ terioL33:848. 9. S S -- SR 1929. Tubercle 10: 404. Asbestos Dust , B ioOffice. London, ^ngiand- Industry- H- M; st8Uom> .osis and Asbestosis) ACT. 1930. H12. WS iloirckomsiesna'sndCoAmsbfeesntsoasti1son(M(etlicai AAlriraangkem ents) Schem e. 1931 13 A sbestos I ndustry Regulations. 1931 4 * % & fr % I