Document ga9nxoyV1ek64ZV7BG0xNVm2q

EMPLOYEE RELATIONS DEPARTMENT MEDICAL DIVISION WILMINGTON, DELAWARE TO: ALL PLANT PHYSICIANS FROM: C. A. D'ALONZO, M. D. November 9, 1964 . SUBJECT: AS5E3TOSIS The attached summary of a Conference on Asbestos is is a "Trip Report" to us by Dr. G. J. Stopps, 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. ,`01 iOfliOT DUP 0900386 DU 021783 feaaa- - iiiHiiH'itiiaaaniaiga* TRIP REPORT Conference on Biological Effects of Asbestos '-.eld Monday, Tuesday end Wednesday, October 19, pg and 01, ;c*c4 under the auspices of the New Yortc Academy-of Sciences*' the Section of Biolorlcal and Medical Sciences Although this was a well-conducted and well-attended r.eeti-g there being seme three to fo'ur hundred persona present at almost every session,' thore was also a foaling that there were several ghosts present at tne banquet of information presented. No doubt this feeling largely stenased froa the fact that out of soae 53 papers given, only two of them wore given by people connected with the asbestos industry in the United States and Canada, whereas there were seven given by representatives of the asbestos Industry in Britain and a further three or four papers were given by persons connected with the asbestos industry in South Africa. Proa-the point of view of"the Dufoft ~Conpany-aa a whole7 'trie'' sain interest of the meetings was in drawing attention to the fact that aabeatoala and coaulleatlona of aabeatosla have now been found in ,>eraona~Who would not In the ordinary way cose to mind as being expoae<T~fo asbestos: that is to say, they do not work In asbestos mines, asbestos mills, or asbestos textile factories. Underlining this relatively wide exposure of persons to asbestos was the work of Z. J. Selikoff froa the Mt. Sinai Hospital, New York, who has been studying the workers in the insulation trades in New Yorsc City. The investigation reported concerned 1522 members of tne International Association of Heat and Frost Insulators and Asbestos Workers in the New York-New Jersey metropolitan area. The study included every individual who- was a member of this union on December jjl, 1942, or wno Joined by December 51, 1962. Two hundred aixty-four men were dead on January 1, 1965- and 43 nave died since. Each death was studied. One thousand two hundred fifty-eight men were etill alive and 1117 of these were examined. Thla represents 89.9% of the population at risk. Clinical, radiological and pulmonary function examinations were also made of these man. X-ray ranking of tne degree of asbestosis present in four grades ranging from to J indicated that in those navlng 0 to 9 years of exposure to asbestos, 89.o nad no asbestosis present, while >6 had grade 1. Wnereae witn 40 or more years of exposure, 9^*2JC nad grade 2 astestoals and only p.8 nad none. In an analysis of 3&7 consecutive DU 021784 i9A444 DUP 0900387 'i-h mtism - 2- deaths among asbestos Insulation workers, 53 were found to have carcinomas of the lung, 9 had mesothelioma* of the pleura, 35 had carcinomas of the gastrointestinal tract, and 27 had neoplccza at other sites; 17 of them had asbestosis confirmed at autopsy. The conclusion of this paper was that pulmonary asbestosis was a significant risk of insulation workers in the United States; and it will be noted from the above figures that this papsr touch.;d upon the point developed later by other workers at the Ht. Sinai Hospital that the risk of carcinoma, either of the respiratory tract or of the gastrointestinal tract, appears to be significantly gr.atcr amongst the insulation workers than amongst the general population. At a later session E. C. Hammond of the Mt. Sin.al Hospital group further Imderllned the unusual occurrence of carcinomata amongst the Insulation workers. Plrst of all he noted that in a prospective study of 255 consecutive deaths amongst this group of insulation workers carried out over the years 1543-1962 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). Dr. Hammond then updated his information to include a total of 307 consecutive deaths from January 1, IS1*?# to August 30, 156^. This updating or'hi's-stati*stlc`s~did-Tiot"Bat*rialljr-iffect -the-standings------------ but did serve to underline the fact that deaths due to intra abdominal 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 reasons the accuracy of diagnoses of gastrointestinal tract neoplasms is often insecure. In two-fifths of the such deaths, analysis of all of the available data shewed 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 mesothelioma 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 pathological point of view than any other similar group of workers In anotr.er industry since until the publication of the results there had not been any particular cause for concern that the asbestos insulation workers were showing an abnormal incidence of neoplasie. DU 021785 120495 DUP 0900388 'j^f tSfl'iMliii -fiiBli iiiigj iiiiwitu j|SIIlSSi2i*iinili^iiilii mm y _ A report from Turner Brothers Asbestos Company, Ltd., Rochdale, England, and presented by Dr. J. P. Knox, showed a scnewnat more optimistic story when suitable dust prevention regulations were Introduced and enforced In the asbestos industry. Ir. a mortality study of workers In an asbestos factory carried out prior to the enforcement of the British Acbs3to3 Industry Regula tions excess mortality amongst werxera employed for 20 years and upwards was observed. Lung cancer In association with asbestoais was responsible for a considerable proportion of tnis excess. A study of a group of workers from the same factory 'exposed since the regulations went into effect shews a reduction in mortality rate without an excess of lung cancer. Dr. Har.mor.d had pointed out in nis paper tnat tn? extreme rarity of pleural mesothelioma in ths general population meant the finding of even a very few cases in a particular study in industry was nignly significant. Dr. P. C. Limes of Eelfast, Ireland, tackled the problem of mesothelioma from another point of view. He had studied 42 caues of pleural 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 work was obtained in 32 of the cases compared wi th only 5 of 42 matched controls. Asbestos bodies were found In the lungs of 8SjZ of patients with mesothelioma of the pleura, 20? of patients with carcinoma of tne bronchus and 20.5? of patients dying of nonmalignant disease. The frequency of finding of asbestos bodies in tne lung is nlgner (27?) In men dying of non-mallgnant disease between 60 and 69 years of are who went into Industry between 1505 and 1515 than in the 50 to 59 age group wno started work between 1515 and 1525. Eetween 1Sj6 and 1923 over 1000 tons a year of boiler composition were Imported Into Belfast compared with 6C0 tons a year at other times. This boiler composition was an Insulat ing material containing a considerable proportion of asbestos fiber. Dr. Limes pointed out that the latent period for the development of pleural malignancy after exposure may be up to forty years so that Increasing numbers of cases arislns 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 flow generally accepted. More recent Investigation had shown that there was.an Increased incidence of pleural and peritoneal mesotheliomas occurring In people educationally or environmentally exposed to asbestos dust. In some of "these c&2es the exposure has been extremely slight and .not sufficient to produce the histological features of asbestosla. The only patnolorlcal 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. DU 0217861 1 r>aA cx DUP 0900389 4 nearly all of these cases have teen confined to one asbestos mining area. The majority of these people were -:ot employed *n the asbestos manufacturing industry. Chemical investigations have shown that oils containing carcinogenic hydrocarbons are ores.--nt naturally in this ^articular type of asbestos. Another study taking much the same approach as that reported by Dr. Lines of Belfast was reported by Muriel `.'ewhouoe of the London School of Hygiene and Tropical Medicine. Dr. Kewhouoe" reported on a series of patients attending a large hospital in the cost end of London. Dr. .Vewhouse's patients were divided into tvo groups; the first consisted of 83 patients in 'whom the diagnosis cf r.csotr.sliona had been confirmed at autopsy or by biopsy. In all but seven the past occupational and domestic histories ware obtninni. In 21 patients the tumor was peritoneal in origin and in 62 it v_s pleural. The`earliest recorded death was 1917 but only ten of ths series died before 1950; 55 of the males and 4255 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 was 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; 52.656 of those suffering from mesothelioma had been exposed to asbestos as compared to 11.8J5 of the control group. Three main types cf exposure were recognized; work in factories manufacturing asbestos textiles. Insulating materials and other products, employment as laggers 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 1&13 and was until recent years a heavy user of crocidclite. All these whose records could be traced worked with this type of asbestos. Amongst the 36 i-atlents with noaotheliomata with no positive occupational hiatory 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 mesotheliosa-llke 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 mesothelial tumors from autopsy records was given by W. Glyn Cv;en, 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 12049? DUP 0900390 DU 021787 -5- cases. None of a similar number of subjects with cancers of otn.r sites were known to have handled asbestos. Of those giving an occupational history of asbaotoo exposure, five were lagg-rs ttvicyed by firms of insulation engineers and two ware boiler rakers (shipbuilding), two patients ware employed by aackvc.re manufacturers and had .handled old sacks which had contained asbestos. Only two of the 17 patients had worked in eobeotos factories, and one patient gave a history of close environmental exposure having worked in the offices of concrete manufacturers using asbestos cement. Dr. William D. Buchanan, Ministry of Labour, London, pointed out tr.at earlier studies of the British Vital Statistics records indicated an apparent association between the presence of anbsstosis and the finding of a thoracic tumor; although cucn an association had teen postulated soma years before 1947, it was believed that tne study reported in that year was the first occasion when tnese findings nad been related to a sizable group. The proportions so affected appear to be increasing in more recant studies. Up to the end of 1962, 534 death certificates recording tne presence of a3bestosis nave been obtained and annual totals of such certificates were currently increasing. The proportion alto recording a thoracic tumor has also In both sexes continued to Increase disproportionately to the total number so that currently over 5GJ2 of the males dying with asbestosis present have also a neoplasm. Lven when viewed against the steadily rising incidence of lung cancer in the population as a whole. Dr. Bucnanan felt that tnere was little doubt that tnis Increase was a real one. Dr. Bader presented an interesting series of 17 cases of employees actively working .a an asbestos factory ben years ago as which time the plant iiv whicn the men were employed discontinued operation. The men have been followed since that time with serial clinical, radiological and pulmonary function investigations. Baring the baseline studies, pulmonary function examinations _whon abnormal, revealed the classic findings of the alveolar capillary block syndrome/*uniform decrease in lung volumes, well-preserved maximum breathing capacity, decreased arterial oxygen saturation (especially on exercise), normal pCOa values, and decreased diffusing capacity.*) Hyperventilation at rest and exercise occurred i,, more than half tne cases, and dead space ventilation and alveolar ventilation were Increased. The, most sensitive lndex_of impaired function was arterial oxygen saturation. . Slight, reduction at" re at was-fou: id" i n six, and reduction oeiew 9^5" was found .in half ofTtne" workman on exercise. The'^-oat-employment serial evaluations were made" in terms of x-ray progression, developmenc or worsening of dyspnea on exertion and further measurements of pulmonary func tion. Follow-up observations were limited by complications of the disease being studied. Of the 17 men studied ten years ago, 8 men are now dead; 2 of lung cancer, 1 of pleural mesothelioma, 2`of gastric carcinoma, and 2 of pulmonary asbestosis (cox^e pulmonale), /20498 DUP 0900391 DU 021788 6- - and 1 of myocardial infarction. Nine of the ordinal worVczcn are still alive, one following the resection of a luritt or lung cancer. 1-0 capers were presented by workers from Britain discussing Che value of routine lun function studies. In the first, "css Hu.'.t, of British Belting and Atbastos, Ltd., Yorkshire, England, gave the results of routine lung function studies on 3lJ employees in an asbestos processing factory. Routine ork in this field of lung function was started in July 1J60 in an asbestos textile plant in the north of England. The ain was to create a set of normal figures for lung ccr.part.~ent val.u s, cas transfer factor coefficients, 9C mixi.-g indices, ventilation on e/.erelse, and forced breathing, capacities. The subjects used in these tests nice volunteers of both se'.es in varying age and stature groups from departments other than those procc-seing asbestos. These results were then enalysea statistically and the regression formal* a obtained applied to the results of men and women wording in these occupations exposed to asbestos. Pulmonary function tests were al;;o sed as a screen to prevent people with lung impairment from taking up work m departments where asbestos dust was prevalent. Some difficulties were encountered in the beginning both In subject response and sampling technique. Eut these were overcome and this paper deals in the main with the technique and results obtained over tne past tnree years. The evidence points to a significant decrease in gas transfer and vital capacity before any radiological cr cITnicai ai .n& are evident"^ "` The other paper given ty M. L. Thomson and V.'. J. Saither, from the London School of Hygiene and Tropical Medicine and from Cape Insulation and Asbestos Products, Ltd., London, England, Indicated that Inspiratory capacity and vital capacity were the best discriminates of astestosls amongst the many pulmonary function tests used. It would appear from tne concensus at this meeting that the risk of persons not normally thought of as engaged in. work with asbestos, and certainly not thought of as being in the asbestos industry, is ,reater than was originally thought. . This fact should be borne in mind and embraces not only the person's occupation but also his hobbles - for Instance, a do-it-yourself worker at home can have a material exposure to asbestos during hone insulation. Since tne prognosis for a diagnosed pleural mesothelioma is extremely poor, varying from a few weeks to one year. It is important that no persons within the company should be exposed to asbestos whetner as fran< asbestos fiber cr 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 there is no reason to believe that gcod industrial .nygiene practice such as tne u3e of masks when cutting asbestos or using ^owdered or fibrous asbestos products is not completely effective in preventing later disease. It is whether / DUP 0900392 129499 DU 021789 -7or not asbestos fiber penetrates through the respiratory pasoa^es that matters and not trie classification of the nan's occupation. For ..arsons who would like more information on this topic, tr.e Lbstracts 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. 1 OJS/dyb DUP 0900393 120599 DU 021790