Document daMQa4mbXQ9ZEDNGZvqm42nLe

/ <N EMPLOYEE RELATIONS DEPARTMENT MEDICAL DIVISION WILMINGTON, DELAWARE J'' TO: ALL PLANT PHYSICIANS FROM: C. A. D'ALONZO, M. D. cc: F. A. C-i Wardenburg November 9, 1964 SUBJECT: ASBESTOS IS The attached summary of a Conference on Asbestosis 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. 'Y- up nm 03 C j DU 055095 TRI? REPORT Conference on Biological Effect* of Aabeatoa 'eld Monday, Tueaday and Wednesday, October 19. --0 and Cl, l-64 under tne auspice* of tn* New Yoric Academy of ocieneea tne Section of Biological and Medical Science* Although tni* was a well-conducted and well-attended meet! tnere oeing bom tnree to four hundred persona present at almoat every aeaaion, tnere waa also a feeling that there were several gnosts preaant at tne banquet of information presented. No doubt tnls feeling largely atenon*d from the fact that out of aco* 5' paper* given, only two of them were given by people connected witn tne aabeatoa industry in the U.lted State* and Canada, whereas tnere were aeven given by repreaentativea of tne aabeatoa lnduatry in Britain and a further tnree or four ^apers were given by ;.eraons connected witn the aabeatoa lnduatry in South Africa. ?i'om the point of view of the Du Pont Company aa a whole, tne main interest of the meeting* waa In drawing attantlon to tne fact tnat asbeatoala and complication* of aabeatoaia have now been found in .eraona who would not in the ordinary way come to mind as being exposed to asbestos; that ia to say, they do ,ot worn in asbestos mines, asbestos mills, or asbestos textile factories. Underlining this relatively wide exposure of persons to asbestos waa tne worvc of I. J. Sellxoff from the Mt. Sinai Hospital, New York, who nas been studying the worker* in the insulation trade* in New York City. The investigation reportad concerned 1522 members of tne International Association of Heat and Proat Inaulators and Aabeatoa *orkara in the New York-New Jersey metropolitan area. ITie study Included every individual who' was a member of this union on December Cl, 1942, or wno Joined by December J1, 1962. Two hundred sixty-four men were dead on January 1, I96C and 4J nave died alnce. Lacn deatn waa studied. One thousand two hundred flfty-elgnt men were atill alive and 1117 of these were examined. This represents 89.9% of the population at risk. Clinical, radiological and ;ulmonary function examinations were also made of tnese men. X-ray ranging of tne degree of asbestosls preaent in four grade* ranging from ~ to J indicated that in those navlng 0 to 9 years of exposure to asueatoa, 39.6% nad .no aabeatoaia present, while >656 had grade i. knereaa witn 40 or more year* of exposure, 94.2% nad grade 2 aabeatoaia and only p.8% nad non*. In an analysis of 3C7 consecutiv DUP 1 n i J04 DU 055096 deaths among asbestos insulation workers, 53 were found to nave carcinomas of the lung, 9 nad mesotheliomas of the pleura, 35 had carcinoma* of the gastrointestinal tract, and 27 had neoplasms at other site*; 17 of them had asbe*to*i* confirmed at autopsy. The conclusion of this paper was that pulmonary asbestosls 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, appeare to be significantly greater amongst the insulation workers than amongst the general population. At a later session E. C. Hammond of the Mt. Sinai Hospital group further underlined tne unusual occurrence of carcinomata amongst the insulation workers. First of all he noted that in 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) aa were deaths caused by cancer of lung and pleura (observed 45, expected 7) and stomach and colon (observed 29, expected 1C). Dr. Hammond then updated nis information to include a total of 3C7 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 nave 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 49 such deaths, analysis of all of the available data snowed tne 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 mesotnelioma may be even more common than the 5 out of 307 deatns recorded. In addition to tne neoplasia amongst the recorded deaths, there were three men alive with known neoplasms (l lung cancer, 1 pleural, and 1 peritoneal mesotnelioma), 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 nad presumably not been more intensively studied from the pathological point of view tnan any other similar group of workers in anotner industry since until the publication of tne results t.nere had not been any particular cause for concern that the asbestos insulation workers were snowing an abnormal incidence of neopxasia. DUP 1111105 c DU 055097 A report from 'Turner Brother* Asbestoe Company, Ltd., Bocndale, England, and ^resented by Dr. J. P, Knox, snowed a 2~tlewnat more optimistic story when suitable duet prevention regulations were Introduced and enforced In the asbestos Industry. In a mortality study of workers In an asbestos factory carried out prior to tne enforcement of the British Asbestos Industry Regula tions excess mortality amongst workers employed for 2C years and upwards was observed. Lung cancer in association with asbestos!* was responsible for a considerable proportion of tnls excess. A study of a group of workers from the same factory exposed since the regulations went into effect shows a reduction In mortality rate without an excess of lung cancer. Dr. Hammond nad pointed cut in ms paper tnat tne extreme rarity of pleural mesothelioma in tne general population meant the finding of even a very few cases in a particular study in industry was hignly significant. Dr. ?. C. Limes of Belfast, Ireland, tackled the problem of mesothelioma from another point of view. He had studied 42 cases of rleural mesothelioma found in his department In Belfast over tne oast 14 years; tne population at risk being about tnree-quarter of a million people. A positive history of exposure to asbestos at work was obtained in 52 of tne cases compared with only 9 of 42 matched controls. Asbestos todies were found in the lungs of 88 of patients with mesothelioma of the pleura, 2C^ cf patients wion carcinoma of tne bronchus and 20.5% of patients dying of no.nmalignant disease. The frequency of finding of asbestos bodies in tne lung is nigner (2756) in men dying of non-malignant disease cetween oO and 69 years cf ase who went into industry between and 1915 than in the 50 to 59 age group wno started work between 1915 and 1925. Between 19u6 and 1925 over 1000 tons a year cf boiler composition were imported into Belfast compared with 6CC tons a year at other times. This boiler composition was an i.nsulat i.ng material containing a considerable proportion of asbestos fiber Dr. Elmes pointed out tnat tne latent period for the development cf pleural malignancy after exposure may be up to forty years so tnat 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 bet'ween asbestos and pulmonary malignancy waa now generally accepted. More recent investigation nad 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 asbeatosis. "Tie only pathological evidence of exposure has been the presence cf aaoestos bodies or fibers in the air spaces. In South Africa more tnan 100 cases of this tumor nave been confirmed histologically.1 DUp 1 11 *IQ6 DU 055098  >.i B 4SK- 'jWMttMHFj-^ -4- Nearly all of these caaea nave teen confined to one asbestos mining area. The majority of these people were :ot employed *:i t.ne asbestos manufacturing industry. Chemical investigations nave sr.ow.n that oils containing carcinogenic nydrocarbons are present .naturally in this ^articular type of asbestos. Another study taking much the same approach as that reported by Dr. Elmes of 3elfast was reported by Muriel Newhouse of the London School of Hygiene and Tropical Medicine. Dr. Newhouse reported on a aerlea of patients attending a large hospital in the eaat end of London. Dr. Newhouse1a patients were divided into two groups; the first consisted of 83 patients in whom the diagnosis of mesotnelioma had been confirmed at autopsy or by biopsy. In all but seven the ^ast occupational and domestic histories were obtained In ..I ^atients tne tumor was peritoneal in origin and In 62 it was pleural. The earliest recorded deatn was 15# 17 but only ten of the series died before 1*50; 55% of the males and k2% of the females died under the age of 55. The interval between tne first exposure and development of terminal illness ranged between 16 and 55 years, tne mean was 57. The second group consisted of ?6 patients at the same hospital, matched by sex ar.d date of birth with those traced in tne first series; 5^.6% of those suffering from mesothelioma had been exposed to asbestos as compared to II.85I of the control group. Three nam types of exposure were recognized; work ;n factories manufacturing asbestos textiles, insulating materials and otner products, employment as laggers or Insulators, and exposure to dust brougnt home by relatives working with asbestos. Eighteen of those employed in factory work or_Mhose relatives were, worxing >itn asbestos were employed in one factory. This'factory opened in l-15 and was until recent years a neavy user of croc-dclite, /II those whose records could be traced worked wictL. this--ty^e of-asbestos. Amongst the 36 ; atlents wltn mesothelloraata wit.n no positive occupational nistory and no relatives living at home wording wltn asbestos, tnere were il 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 tne two aeries was statistically significant. Dr. Ian Webster, of the Pneumoconiosis Research Unit, Johannesburg, South Africa, pointed cut in his paper that althougn animal experiments have succeeded in showing the p:owth of a mesothelioma-like tumor in animals in 'which the asbestos was -noculated directly into the ..leura, ;t nad 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. Qlyn Owen, of Liverpool, England. Seven teen cases were selected as good examples of diffuse mesotheliomas. Sixteen of tnese were pleural and one was peritoneal. Evidence of asbestos exposure was obtained in 14 (82%) of the 17 mesothelioma DUP tin 107 DU 055099 -5- Nona of a similar number of subjects witn cancers of otner sites ware Known to nave nandled asbestos. Of tr.ose giving an occupational history of asbestos exposure, five were laggers employed by firms of Insulation engineers and two were boiler makers (snipbuilding), two patients were employed by sackware manufacturers and load nandied old sacks wnich had contained asbestos. Only two of tne 17 patients had worked in asbestos factories, and one patient gave a history of close environmental exposure naving wonted in tne offlcea of concrete manufacturers using asbestos cement. Dr. William D. Bucnar.an, Ministry of Labour, London, pointed out mat earlier studies of the British Vital Statistics records indicated an apparent association between the presence of asbestosis and the finding of a cnoraoio tumor; although such an association nad been postulated some years before 1547, it was celieved tnat tne study reported in that year was the first occasion when tnese findings nad been related to a sizable broup. The proportions so affected appear to be increasing in more recent studies. Up to the end of 156(5, death certificates recording tne presence of asbestosis nave been obtained and annual totals of sucn certificates were currently increasing. The proportion also recording a thoracic tumor nas also in both sexes continued to increase disproportionately co the total number so that currently over of tne males dying with asbestosis present nave also a neoplasm. Lven wneu viewed against tne steadily rising incidence of lung cancer in tne population as a wnole. 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 .n an asbestos factory ten years auo at wnicn time tne plant in wnlcn the men were employed discontinued operation. The men nave ueen followed since tnat time witn serial clinical, radiological and pulmonary function investigations. During tne baseline studies, pulmonary function examinations wnen abnormal, revealed tne classic findings of tn# alveolar capillary block syndrome, uniform decrease in lung volumes, well-preserved maximum breathing capacity, decreased arterial oxygen saturation (especially on exercise), normal pCO values, and decreased diffusing capacity. Hyperventilation at reBt and exercise occurred in more than half tne cases, and dead space ventilation and alveolar ventilation were increased. The most sensitive index of impaired function was arterial oxygen saturation. Slignt reduction at rest was found .n six, and reduction oelow Saji was found in naif of tne workmen on exercise. The post-employment serial evaluations were made in terms of x-ray progression, development or worsening of dyspnea on exertion and furtner measurements of pulmonary func tion. ?ollow-up observations were limited by complications of the disease being studied. Cf tne 17 men studied ten years ago, 8 men are now dead: 4_ of lung cancer^.l_of pleural mesothelioma, a of gastric carcinoma, and 2 of pulmonary asbestosis (core pulmonale), 0 DU 055100 and 1 of myocardial infarction. Nine of the original workmen are still alive, one following one reflection of a i_r,.g or lung cancer. Two ,apers were presented 'ey workers from Britain discussing tr.e value of routine lun* function studies. I.i the first, Boss Hunt, of Britisr. 3elting and Asbestos, Ltd., Yorkshire, England, gave tne results of routine lung function studies on 8l3 employees in an asbestos processing factory. Routine work _n tr.is field of lung function was started in July I960 in an aabestos textile plant in tne north of England. The aim was to create a set of normal figures for iun^ compartment val.ues, cas transfer factor coefficients, SC mix! g indices, ventilation 0 : exercise, and forced breathing capacities. The subjects used in tnese tests were volunteers of cotn sexes in varying age and stature groups from departments otr.er than tnose processing asbestos. These results were c.nen analysed statistically and tne regression formulae obtained applied to the results of men and women working in those occupations exposed to asbestos. Pulmonary function tests were al*o -sed as a screen to prevent people with lung impairment from taxing up work _r. departments wnere asbestos dust was prevalent. Lome difficulties were encountered in tne beginning both .n subject response and sampling tec.nnique. But these were overcome and tnia paper deals in tne main witn the technique and results obtained over tne past tnree years. . The evidence' points to a significant decrease in jas transfer and vital capacity before an;, radiological or clinical si0ns are evident. Tr.e otner ra;.er given by M. L. Thcmion and . J. Smitr.er. from tne London Sc.nool of Hygiene and Tropical Medicine and from Ca^e Insulation and Asbestos .-rouuct3. Ltd., London, England, indicated tnat inspiratory capacity and vital capacity were tne test discriminates of astestosls amongst the many pulmonary function testa used. It would appear from tne concensus at this meeting that tne risk of fersor.s not normally trought of as engaged In worse witn asbestos, and certainly not tnoug.nt of as being In tne asbestos Industry, Is greater than was originally thought. This fact should be borne in mind and embraces not only tne person's occupation cut also his hobbles - for Instance, a do-it-yourself worxer at ncme can nave a material exposure to asbestos during home insulation. Since tne prognosis 'forr-a^dTanr.csfa pleural meaotnerioma la extremely poor, varying from a few weexs to one year, it la Important tnat no persons wltnin the company snould ce exposed to asbestos whet.ner as fran.< asbestos-*Iber bb^aabestos contained in Such materials as insulation, lagging, asbestos cement, etc. It is also of course important to present tr.is type of information in perspective and not to cause undue alarm since tnere is no reason to believe tnat good -r.duatrlal nygiene practice suen as tne use of masks when cutting asbestos or using ^owdered or fibrous asbestos products is r.ct completely effective :n preventing later disease. It is wnet.ner DUP 111 1109 DU 055101 i zc not asbestos fiber penetrates throu^n tne respiratory passages that matters and not tne classification of the nan's occupation. For ..eraor.s whc would like more .nformation on this topic, tne abstracts of the Conference on the Biological Effects of /sbestos are available from tne writer and it is expected that th* ^roceedinofl of the conference will be published within the year. GJS/dyb dup m i no V.- w .L ~ O - DU 055102