Document gbp3gKxRgEnjxzQ3YVKeMDYBV

FILE NAME: Uniroyal (UNIR) DATE: 1964 Nov 17 DOC#: UNIR020 DOCUMENT DESCRIPTION: Letter to US Rubber Co. from John G. Wells RE Conference on 'Biological Effects of Asbestosis1 JOHN G. W ELLS. M. D. *! JE F F E R S O N STREET NCWNAN. GEORGIA TtLCPMONl AL 3*0611 12 November 19SU Mr. A.C. Link United States Rubber Company Hogansville, Georgia Dear Mr. Link: r ^ i ,, SiSUld like thank yu and the United States Rubber company for the opportunity and very great pleasure of attending 0eber19-u" Ss!?' n "sloloSical * oi Asbestosis" on 8 t oonferance was sponsored by the New York Academy of * d S international conference, attended by active workers in the field of Asbestos from the British Isles several areas m the United States. f SUth A f r i c a r c a n a d a a n d1 Tel ma Zt1a *' V of *h discussants traveled from the British Isles and South Africa where interest and continuing investigations o?nbeev 41iltlate.by the si2nal report of Merewether and Price in C^.*Stabllshad the occupational origin of asbestosis and made this disease a "certifiable" and corapensatable disease. - jd15? recent conference on biological aspects of asbestosis dedJint ^ Part3** th fi^st relating to the broad asoects St and as^**tos disease; and the second, to the seeminslv . nS increase in incidence of bronchogenic carcinoma and mesotheiioraata of pleura and peritoneum. These noplasie disease have been found with increasing frequency in individuals whose initial exposure to Asbestos dust has exceeded twenty years. Rather impressive data to demonstrate this development were presented by Selikoff, Smither, Buchanan and others. However, no evidence was given which was of correlative significance in regards * asestos dust; or to the nature, amount and conditions or initial and subsequent exposure. Of perhaps even greater significance in this regard was the re^firt of Dr. John Knox of Turner Brothers Limited, who compared two groups of people with twenty yeare or more exposure gained before and after 1933. , the first group, there was a very significant increase in the number of deaths from all causes; all neoplasms, and cancer of the lung and pleura. . nrour Of the tventv-years-exposure rren studied after 19.13, the number of observed deaths in cnlv slight1v greater than the expected mortality rate? and the number of deaths due to all neoplasms, and cancer of the lung and pleura, is in fact less than that which was anticipated for the population at large. ' N<; conclusions were drawn from these observations by Dr. Knoxt but it was pointed out both by him and Hr. Hill, of the same company, that .ollowing 1933, extensive and continuing efforts at dust control have been employed in their factory. A great amount of experimental work has been done both In thie country and abroad purporting to demonstrate the ability of of the pleura. Produc bronchogenic carcinoma and mesothelioma ta ?oina Interest is the work of Smith and Hiller at Fairleirh Di*iuson University, Madison, Hew Jersey, who, using chrysotile and amosite fibers, inoculated hamsters both intratracheallv and intra pleurally with massive doses of the fibers. They did not report one case of neoplasia by the intratracheal route; but did report numerous cases of neoplasia following the intrapleural route of injection, which is of course, not experienced by human beings. In summary, in regards to neoplasia, the reported findings related largely to a group of workers in various asbestos industries, including large bodies of insulation workers (non-textile workers) whose exposure occurred several decades ago; and prior to a time when Increasing awareness of a potential occupational hazard generated a continuing interest and activity towards effective dust control. The first half of the conference pertained largely to the descriptions of Asbestos disease in various parts of the world; the experimental production of asbestosia; and the efforts of various industries and fact findings bodies-- most particularly in the British Isles and South Africa-- towards investigating the grass anatomic, microscopic, radiologic, and pulmonary functional aspects of asbestos disease. not It was demonstrated that/only did microscopic particles of asbestos dust of various size enter into the lungs and produce asbestos bodies and subsequent pulmonary fibrotic changes; but it was also demonstrated most remarkably by Dr. Davies of the Asbestos Research Council at tha University of Cambridge in England, using electron microscopy and selective iron staining dyes, that ultra microscopic particles were also incorporated into the lung and nicked up by the lung phagocytes. This particular work is being carried on actively and the results in terms of production of ashestos disease are not at present known. Ko conclusion wan drawn, but one must entertain the speculation that asbestos fibers of not only microscopic but of also ultra-microscopic size may be implicated in the formation of pulmonary asbeatosis. * 3-- A most interesting study was reported by Kiviluoto of Finland who described a rather peculiar tyre of pleural calcification not only in the workers m local Asbestos mines, but also in the population at large in an area extending peripherally from the mines. mef8UrinS anthophyllite, found that at a distance of one-half kilometer from the mines there were twelve to thirty-four grams of anthophyllite dust per hundred square meters ; and that at a distance of one and one-half kilometers there were six to twelve erams- 1,38 s r s m s i in d a t f i f t y findings, again, pointed out the theoretical and practical importance of dust control, not onlv for immediately ex posed workers, but for the community at large* There were many other papers on the radiologic changes of pulmonary asbestosis; and there were reports relating to the sequential pulmonary physiological changes seen in asbestosist and there were encouraging data relating to the decreased incidence of Asbestos disease in areas where good dust control had been engineered. It can be said that the bulk of the reported work related to isolated parameters of asbestos disease. Moreover, it was ay personal observation, that with some very significant exceptions, the major portion of material and evidence presented described experiences and findings long past and not immediately applicable to the present. It was lamented by Dr. John C. Gilson of the Pneumoeonisosis Medical Research Council of Great Britian, one of the chief protagonists of this meeting, that none of the studies made significant correlations of clinical, radiologic, physiologic and dust counting data. With this thinking in mind, and at the end of the meeting I was given the opportunity to describe some things about the work and findings of our own program at the United States Rubber Mill in Hogansville, Georgia. Having been originally requested to limit the remarks to three minutes, I was allowed to speak for some fifteen or more minutes, and it appeared that the comments were well received. It has been the purpose of our own study to learn as much as possible regarding the nature of asbestosi3 in this particular Hogansville environment; and of greater correlary significance, to ascertain the earliest moment at which significant changes occurred, in order that workers might be removed from the asbestos atmosphere. The work already accomplished and criteria established have, in our mill, gone a long way to protect the workers and the company. Vanished is the air of concern and even apprehension which wa3 nascent in the raid nineteen fifties. -U - beinc nroteetea Tn f**r xnat their health interesatnsd athree h a iS \S 3 u ? ? ik i iv 0 r ? v r! i T ' 1 medical T i t i a n s to seek prov.ntiv. c i ' lnStanC'S "*, A few basic conclusions and observations can be presented. Exposure to asbestos dust can produce pulmonary asbestosis. to an accSJlft iff?I?iieSi8sUifath ?iIiSSriI!eiohOUld 5roIone th* orkiSp time and tSis ?o SS casS? d e,nploy ` CuiTM * evidence indicates dust xPsur (measured here in million ^articles the Sroduorinr'ii*578? appaar3 be ?ot the only factor implicated in of ^ of pulmonary asbestosis. There are several instances hLe al ei??sur in different workers, some of whom nave asbestos disease, while others do not* : 7116 **?ianation is not immediately forthcoming* However, I!!? *ar<i SOme int4r*sting loads pointing to the type of work (eg, T* waav?r * a*e), type of responsibility (eg, supervisor or of ehiiA<fovth br?!ihing *ersus nos breathing, presence or absence K i i ? ^ niCibr0nclli5is] an? P*rhaPS an hereditary increased susceotibility as in mucoviscidosis, .. . . .,,T*1?1** remains the further presently snipmatic possibility ?!? exposure to high dust concentrations, such as occurred ?arly *>erationa of this m* H may be more important in the Pulrao"ary asbestosis than the prolonged exposure to low concentrations, against which the workers own physiological defense ihoildi2Ir!y *PrVid? protection* Studies in progress should serve to resolve this problem* .. , We have not, as yet, observed a single worker with cancer of the lung, pleura, stomach, colon or rectum. , ^?por^s at tha recent conference pointed towards the increased incidence of these malignancies twenty years or more following initial exposure. Fragmentary evidence suggested greater risk from exposure to crocidolite dust. Since this mill has used chrvsotile fibers almost since.th*. initial installation of a fly frame and winder as a pilot operation in 1938, it must be hoped that our workers will escape this misfortune. A close watch will be kept for signs of trouble* 1 - 5- Accepting^the stipulation that the pre-eminent cause of pulmonary asbestosis is exposure to asbestos dust fibers, it is a d u s t M n t t S l ^ * 1011 thdt thS prevention of asbestosis rests on effective . ^ criteria of effective dust control are not only the factual evidence of diminished dust counts; but also the abolition of the sequelae of exposure-pulmonary asbestosis, ,, _ P 1* second"line of defense" therefore rests on early de~ taction of tha disease process *i~ We have studied this condition-- as it occurs in Hogansville-- using many points of view. We are now able to make a clinical diagnosis of pulmonary asbestosis at a relatively early stage. There is some evidence at hand suggesting that the disease process is not progressive once the worker has been removed from the dust exposure. ' It is too earlv to draw conclusions in this regard. However, the criteria for diagnosis still rest upon thj demonstration of observable evidence brought about by the pathologic process which is occurring within the lungs, ^ Bytthe time these early changes are demonstrable, significant fibrotic disease of an irreversible nature has occurred, 'The importance of the earliest possible detection is thus readily apparent, It would now appear that the most sensitive means available is the utilization of diffusion studies which measure the rate of diffusion of a gas from the pulmonary alveolus to the pulroonarv capillary-- the site at which the earliest significant pathologic changes occur in asbestosis. We have been using a two level of oxygen method, which while o* sreat informative value, is time consuming and potentially dangerous in older workers of whom we have a considerable number. Carbon monoxide diffusion studies, using very low concentration of the gas, are feasible, safe and relatively rapid; and I would hope that we could further our work using this technique. Infra red analyzer engineered to measure carbon monoxide and carbon dioxide concentrations, are commercially available.