Document nMNrLZe2gO935Ro78w91KLe1

A CC: Dr. J. A. Zapp EMPLOYEE RELATIONS DEPARTMENT MEDICAL DIVISION WILMINGTON, DELAWARE November 9, 1964 TO: ALL PLANT PHYSICIANS FRdft: C. A. D'ALONZO, M. D. Flt. : C* O0 *347 || PIJP~ SUBJECT: ASBESTOSIS The attached summary of a Conference on Asbestosis is a "Trip Report" to us by Dr. G. J. Stepps, of our Haskell Laboratory. It is such a timely and interesting report that we are sending a copy to each of our Plant Physicians. Please note particularly the last paragraph of page 6. If any of you feel that there is any particular question in this regard, we would be pleased to hear from you. CD'A/smr Enel. .;ioktha;<o hefcstiks RECEIVED NOV 11 1964 HASKELL LABORATORY DUP 0930056 TRIP REPORT Conference on Biologic*! Effects of Asbestos neld Monday, Tuesday and Wednesday, October 19* .-0 and 21, 1( 64 under tne auspices of tne New York Academy of doiences tne Section of Biological and Medical Sciences Although this was a well-conducted and well-attended meeting tne re being acme three to four hundred persons present st almost every session, tnere was also a feeling that there were several ghosts present at tne banquet of Information presented. No doubt this feeling largely stemmed from the fact that out of some 53 papers given, only two of them were given by people connected with the asbestos industry in the United States and Canada, whereas there were seven given by representatives of tne asbestos Industry in Britain and a further three or four papers were given by persons connected with tne asbestos industry in South Africa. Prom tne point of view of tne Du Pont Company as a wnole, tne main interest of the meetings was in drawing attention to the fact tnat aabestosis and complications of aabestosis nave now been found in ,*ereons wno would not in tne ordinary way com to mind as being exposed to asbestos; that is to say, they do not work in asbestoa mines, asbestos mills, cr asbestos textile factories. Underlining this relatively wide exposure of persons to asbestos was tne work of I. J. Selllcoff from the Mt. Sinai Hospital, New York, who has been studying the workers in tne insulation trades in New York City. The investigation reported concerned 1522 members of tne International Association of Heat and Prost Insulators and Asbestos Workers in the New York-New Jersey metropolitan ares. The study Included every individual who- was a member of tnia union on December 31, 1942, or wno Joined by December 31, 1962. Two hundred sixty-four men were dead on January 1, 1963- and 43 nave died since, taco death was studlsd. One thousand two nundred fifty-eight men were still alive and 1117 of these were examined. This represents 89,9% of the' population at risk. Clinical, radiological and pulmonary function examinations were also made of tness man. X-ray ranking of the degree of aabestosis present in four grades ranging from u to 3 indicated that in those navlng 0 to 9 years of exposure to asueatos, 89.0? had no aabestosis present, while 3^fS had grade 1. wnereat witn 40 or more years of exposure, ^.2% nad grade 2 aabestosis and only 5.8? had none. In an analysis of 307 consecutive DUP 0930057 -2- deaths among asbestos insulation workers, 53 were found to have carcinomas of the lung, 9 had mesotheliomas of the pleura, 35 had carcinomas of the gastrointestinal tract, and 27 had neoplasms ac other sites; 17 of them had asbestosis confirmed at autopsy. The conclusion of this paper was that pulmonary asbeatosis was a significant risk of insulation workers in the United States; and it will be noted from the above figures that this paper touched upon the point developed later by other workers at the Mt. Sinai Hospital that the risk of carcinoma, either of the respiratory tract or of the gastrointestinal tract, appears to be significantly greater amongst - the insulation workers than amongst the general population. At a later session E. C. Hammond of the Ht. Sinai Hospital group further underlined the unusual occurrence of carcinomata amongst the insulation workers. ?lrst of all he noted that m a prospective study of 255 consecutive deaths amongst this group of insulation workers carried out over the years 1943-1962 that the total number of deaths were increased (observed 255, expected 204} as were deaths caused by cancer of lung and pleura (observed 45, expected 7} and stomach and colon (observed 29> expected 10). Or. Hammond then updated his information to Include a total of 307 consecutive deaths from January 1, 1943, to August 30, 1964. This updating of his statistics did not materially affect the standings but did serve to underline the fact that deaths due to intraabdominal neoplasms were also greatly increased over what might have been expected if the death rates of the general population had prevailed. Dr. Hammond pointed out that for a variety of reason! the accuracy of diagnoses of gastrointestinal tract neoplasms is often insecure. In two-fifths of the 49 such deatns, analysis of all of the available data showed the diagnosis to be presumptive only. This was especially true of stomach cancer (8 out of 13} and generalized abdominal cancer (6 of 7), Therefore it is possible that peritoneal mesotnelloaa may be even more common than the 5 out of 307 deaths recorded. In addition to the neoplasia amongst the recorded deaths, there were three men alive with known neoplasms (1 lung cancer, 1 pleural, and 1 peritoneal mesothelioma), as well as one apparently cured of tongue cancer, one of cancer of the colon, and three following successful resection of localized, lung cancer found in this survey. In questions at the end of this paper, Dr. Hammond brought out that the group of workers had presumably not been more Intensively studied from the patnologlcal point of view chan any other similar group of workers in another industry since until the publication of the results there had not been any particular cause for concern that the asbestoe Insulation workers were showing an abnormal Incidence of neoplasia. DUP 0930058 -5- A report from Turner Brother# Asbestos Company, Ltd., Rochdale, England, and presented by Dr. J. P. Knox, showed a aomewnat more optimistic story when suitable dust prevention regulations were introduced and enforced in the aabestos Industry. In a mortality study of workers in an asbestos factory carried out prior to the enforcement of the British Asbestos Industry Regula tions excess mortality amongst worxers employed for 20 years and upwards was observed. Lung cancer in association with asbestoais was responsible for a considerable proportion of this excess. A study of a group of workers from the same factory exposed since the regulations went Into effect showa a reduction In mortality rate without an excess of lung cancer. Dr. Hammond had pointed out in nis paper that the extreme rarity of pleural meaothelloma in the general population meant the finding of even a very few cases in a particular study in Industry was nlgnly significant. Dr. P. C. Limes of Belfast, Ireland, tacxled the problem of raeeotnelloma from another point of view. He had studied 42 cases of ,.leural mesothelioma found in his department in Belfast over tne past 14 years; tne population at risk being about three-quarters of a million people. A positive history of exposure to asbestos at worw was obtained in 22 of the cases compared with only 9 of 42 matched controls. Asbestos bodies were found in the lungs of 88% of patients with mesothelioma of the pleura, 20% of patients with carcinoma of tne bronchus and 20.556 of patients dying of nonmalignant disease. The frequency of finding of asbestos bodies in tne lung is nlghcr (i!756) in men dying of non-malignant disease between 60 and by years of are who went into industry between 1505 and 1915 than in the 50 to 59 age group who started work between 1915 ana 1925. Between 1906 and 1922 over IOOO tons a year of boiler composition were imported into Belfast compared with 600 tons a year at other times. This boiler composition was an insulat ing material containing a considerable proportion of aabestos fiber. Dr. Elmes pointed out that the latent period for the development of pieural malignancy after exposure may be up to forty years so that increasing numbers of cases arising from exposure can be expected for many years to come. Dr. Wagner, of the M.R.C. Pneumoconiosis Research Unit, Glamorgan, Wales, British Isles, noted that an association between asbestos and pulmonary malignancy was now generally accepted. More recent investigation had shown that there was an Increased incidence of pleural and peritoneal mesotheliomas occurring in people occupationally or environmentally exposed to asbestos dust. In some of these cases the exposure has been extremely slight and not sufficient to produce the histological features of asbestoais. The only pathological evidence of exposure has been the presence of asbestos bodies or fibers in the air spaces. In South Africa more than 100 cases of this tumor have been confirmed histologically. DUP 0930059 -4- Nearly all of these case* nave teen confined to one asbestos mining area. The majority of these people were ':ot employed tne asbestos manufacturing Industry. Chemical investigations nave snown that oils containing carcinogenic hydrocarbons are present naturally in this particular type of asbestos. Another study talcing much the same approach as that reported by Or. limes of Belfast was reported by Muriel Newhouse of the London School of Hygiene and Tropical Medicine. Dr. Newhouse reported on a series of patients attending a large hospital in the east end of London. Dr. Newhouse's patients were divided into two groups; the first consisted of 83 patients in whom the diagnosis of mesotnelloma had been confirmed at autopsy or by biopsy. In all but seven the past occupational and domestic' histories were obtained. In 11 patients the tumor was peritoneal in origin and in 62 it was pleural. The earliest recorded death was 1^1? but only ten of the series died before ly50; 55% of the malts and 42$ of the females died under the age of 55. The interval between the first exposure and development of terminal Illness ranged between 16 and 55 years, the mean waa 37. The second group consisted of ?6 patients at the same hospital, matched by sex and date of birth with those traced in the first series; 52.6$ of those suffering from mesothelioma had been exposed to asbestos as compared to 11.8$ of the control group. Three main types of exposure were recognized; work in factories manufacturing asbestos textiles, insulating materials and other products, employment as larger3 or insulators, and exposure to dust brought home by relatives working with asbestos. Eighteen of those employed in factory work or Whose relatives were working with asbestos were employed in one factory. This factory opened in iyi3 and was until recent years a heavy user of crocidollte. All those whose records could be traced worked with this type of asbestos. Amongst the 36 patients with mesothellomata with no positive occupational history and no relatives living at home working with asbestos, there were 11 who lived within half a mile of an asbestos factory. Five of the control series also lived in the same area. The difference In the proportion of patients in the two series was statistically significant. Dr. Ian Webster, of the Pneumoconiosis Research Unit, Johannesburg, South Africa, pointed out in his paper that although animal experiments have succeeded in showing the growth of a mesothelioma-like tumor in animals in which the asbestos was inoculated directly into the pleura, :t had not been possible to produce carcinomata by exposing the animals to an asbestos dust cloud. A further study of pleural meaothelial tumors from autopsy records was given by W. Qlyn Owen, of Liverpool, England. Seven teen cases were selected as good examples of diffuse mesotheliomas. Sixteen of these were pleural and one was peritoneal. Evidence of asbestos exposure was obtained in 14 (82$) of the 17 mesothelioma DUP 0930060 -5- cases. Nona of a similar number of subjects with oancsrs of otner sites were xnown to nave handled asbestos. Of those giving an occupational history of asbestos exposure, five were laggers employed by firms of insulation engineers and two were boiler makers (anipbuildlng), two patients were employed by saoKware manufacturers and had handled old aaolca which had contained aabestoa. Only two of the 17 patients had worked in aabeatoa factories, and oue patient gave a history of close environmental exposure naving worked in the offices of concrete manufacturers using asbestos cement. Dr. William D. Buchanan, Ministry of Labour, London, pointed out that earlier studies of the British Vital Statistics records indicated an apparent association between tne presence of asbestosis and the finding of a cnoraclc tumor; although sucn an association nad been postulated some years before 19^7, it was oelleved that tne study reported in that year was the first occasion when tnese findings nad been related to a sizable group. Tne proportions so affected appear to be increasing in more recent studies. Up to the end of 1962, b84 death certificates recording tne presence of asbestosis nave been obtained and annual totals of such certificates were currently increasing. The proportion also recording a thoracic tumor has also in both sexes continued to Increase disproportionately to tne total number so that currently over of tne males dying with asbestosis present nave also a neoplasm, tven wnu viewed against tne steadily rising incidence of lung cancer in the population as a wnole. Dr. Bucnanan felt that tnere was little doubt that- tnls Increase was a real one. Dr. Bader presented an interesting aeries of 17 cases of employees actively woricIng .n an asbestos factory tan years ago at whicn time the plant in whicn the men were employed discontinued operation. The men nave been followed since tnat time with serial clinical, radiological and pulmonary function investigations. During tne baseline studies, pulmonary function examinations when abnormal, revealed the classic findings of the alveolar capillary bloctc syndrome, uniform uecrease in lung volumes, well-preserved breathing capacity, decreased arterial oxygen saturation (especially on exercise), normal pCOa values, and decreased diffusing capacity. Hyperventilation at rest and exercise occurred iu more than naif tne cases, and dead space ventilation and alveolar ventilation were increased. The most sensitive index of impaired function was arterial oxygen saturation. Slight reduction at rest was found in six, and reduction below 925* was found in half of tne wortaaen on exercise. The post-employment serial evaluations were made in terms of x-ray progression, development or worsening of dyspnea on exertion and furener measurements of pulmonary func tion. Pollow-up observations were limited by complications of the disease being studied. Of tne 17 men studied ten years ago, 8 men are now dead; c of lung cancer, 1 of pleural mesotnellooa, 2 of gastric carcinoma, and 2 of pulmonary asbestosis (cox's pulmonale), DUP 0930061 .6- and 1 of myocardial infarction. Nina of the original workmen are still alive, one following tne resection of a lung or lung cancer. Two papers were presented by workers from Britain discussing the value of routine lunu, function studies. In the first, Boss Hunt, of British Belting and Asbestos, Ltd., Yorkshire, England, gave the results of routine lung function studies on 813 employees in an asbestos processing factory. Routine work in this field of lung function was started in July I960 In an asbestoa textile plant in the north of England. The aim was to create a set of normal figures for lung compartment values, cas transfer factor coefficients, 9CJT ir.ixii g indices, ventilation on exercise, and forced breathing capacities. The subjects used in these tests were volunteers of botn sexes in varying age and stature groups from departments other than those processing asbestos. These results were then analysed statistically and the regression formulae obtained applied to the results of men and women working in those occupations exposed to asbestoa. Pulmonary function tests were also used as a screen to prevent people with lung impairment from talcing up work in departments where asbestoa dust was prevalent. Some difficulties were encountered in tne beginning both In subject response and sampling technique. But these were overcome and this paper deals in the main with the technique and results obtained over tne past tnree years. The evidence wolnts to a significant decrease in -as transfer and vital capacity tefore an^~ raalpj.o.-.xcal cr clinical al^ns are evicent. The otner raper given Ly M. L. Thomaoo and V.'. J. Sralther, from tne London Scnool of Hygiene and Tropical Medicine and from Cape Insulation and Asbestos frouucts. Ltd., London, Lholand, Indicated that inspiratory capacity and vital capacity were the best discriminates of aabestoais amongst the many pulmonary function tests used. It would appear from tne concensus at ehls meeting that the risk of persons not normally thought of aa engaged In wenc with asbestos, and certainly not thought of as being in the asbestos Industry, is greater than was originally thought. This fact should be borne In mind and embraces not only the person's occupation but also his hobbies - for instance, a do-it-yoursalf worker at home can have a material exposure to asbestos during hone insulation. Since tne prognosis for a diagnosed pleural mesothalloma is extremely poor, varying from a few weeks to one year. It is important that no persons within the company anould be exposed to asbestos whether as frank asbestos fiber or asbestos contained in such materials as insulation, lagging, asbestos cement, etc. It is also of course Important to present this type of information in perspective and not to cause undue alarm since tnere is no reason to believe that good industrial nygiene practice suen as tne uae of masks wnen cutting asbestos or using powdered or fibrous asbestos products is not completely effective in preventing later dlseaae. It is whether DUP 0930062 -7 cr not asbestos fiber penetrates through the respiratory passages that matters and not the classification of the man's occupation. ?cr persons who would like more information on this topic, the abstracts of the Conference on the Biological Effects of Asbestos are available from the writer and it is expected that the proceedings of the conference will be published within the year. GJS/dyb DUP 0930063