Document 06w2LprxbgMExNg4E6Drw3Mnn

FILE NAME Quebec Asbestos Mining Association QAMA DATE 1969 Apr DOC QAMA008 DOCUMENT DESCRIPTION IOEH Report - Toward the Safe Use of Asbestos \e TOWARDS THE SAFE USE OF ASBESTOS FIBRE An analysis of the current status of the problem and suggestions for further systematic study and development of solutions et Mem rine ween By The Scientific Committee of the Institute of Occupational and Environmental Health Montreal Canada APRIL 1969 Dr. GEORGES W. WRIGHT Director INSTITUTE OF OCCUPATIONAL AND ENVIRONMENTAL Suite 1210 - IBM Building 5 Place Ville Marie Montr^'al113 Canada HEALTH Sponsored by Quebec Asbestos Mining Association Member Companies Asbestos Corporation Limited Thetford Mines Qu^'bec Canadian Mines Limited East Broughton Qu^'bec Bell Asbestos Mines Limited Thetford Mines Qu^'bec Canadian Manville Co. Limited Asbestos Qu^'bec Flintkote Mines Limited Thetford Mines Qu^'bec Lake Asbestos of Qu^'becLimited Black Lake Qu^'bec National Asbestos Mines Limited Thetford Mines Qu^'bec Executive Committee Karl V. Lindell Chairman Michael J. Messel William W. Oughtred F. Parker Smith Ivan Sabourin Secretary Scientific Committee George W. Wright Chairman John Beattie Daniel C. Braun Fernand Gr^'goire Paul Kotin Marvin Kuschner Premysl V. Pelnar Secretary FOREWORD TABLE OF CONTENTS Foreword Introduction ... Section I - Studies dealing with the Maximum Allowable Concentration MAC of Asbestos Fibre in the Environment ofMan Man 12 Section II --- Studies dealing with the Determinants and Mechanisms of the Biological Action of Asbestos Fibre . 19 Section III - Studies dealing with Reducing the Concentration and 26 Numbers of Inhaled Asbestos Fibres Section IV - Studies dealing with Development and Evaluation of Methods in the Preceding Considerations ....s.enr-cmmenmennnmesannnnnre Appendix I - Section One 36 Section Two 45 Section Three 52 Section Four 54 59 Appendix II - Abbreviations FOREWORD The Institute of Occupational and Environment Health was brought about by the Quebec Asbestos Mining Association in 1965 so as to encompass and assess the factual health as exactly as could be ascertained of the asbestos worker a worker surrounded by all the new procedures and methodology of the day with a fibre of asbestos that has become associated if not sometimes merged with many other substances and this under changing modes of operation and changing conditions of circumstance time and place Although our mining association we felt had in the past done its share in the field of industrial health and hygiene it was nevertheless becoming erident that new health problems were mounting and this to a point that only the implementation of an adequate long range scientific research program could bring light to the question a research program planned and evolved so that the needed points of comparison all over the world would be investigated true as it is that the fibre of asbestos is reaching now into so many varieties of uses and commodities at the same time becoming more and more of strategic if not of essential value to humanity The fact is that imputations rather suddenly and violently were now being levelled at the Asbestos Industry as a whole in the field of mining milling manufacturing and processing or in some specific building trades such as that of insulation materials sprayers Even the mere user of asbestos the consumer was being singled out as subjected to serious hazards of exposure Our association a Canadian association already some thirty years old groups together the world chrysotile asbestos mining producers USSR excepted our production having started a century ago and now totalling 3,800,000 tons a year including USSR production - a mining production located in Siberia - the chrysotile asbestos production answering for some % of the overall world asbestos needs the remaining % comprising other types of asbestos belonging to the amphibole family such as crocidolite amosite anthophyllite etc. These imputations against the asbestos industry came primarily from South Africa where the aforesaid types of the amphibole family are also mined save anthophyllite which is mined in Finland The gist of such imputations against the production and use of asbestos was that asbestos would constitute a factor in the causality of cancer whether alone or in association with other factors and conditions Carcinogenicity relating to tumors of the lung as well as of the pleura and of the peritoneum was becoming more and more at times dramatically so linked with the production of asbestos or the mere use of same 5 The alarm was now spreading throughout the asbestos industry field and it was felt our association should take immediate steps so as to seek and coordinate all possible information and data over the whole world in connection with said problems whilst establishing and maintaining contacts with and sometimes emolling into the study such bodies or agencies which were already at work or susceptible of becoming constructive parts of the study Thus our association decided it should carry a substantial share of this responsibility and devote much of its resources time and energy in that direction even if the etiology of the pathological conditions in point should not seemingly impugn chrysotile asbestos as much Hitherto our concern as to the health of the worker in our chrysotile mining industry had been confined to the development and maintaining of preventive industrial measures and safeguards as well as of medical services all of which we thought were adequate particularly as same were supported by organized industrial clinics the first one going back to the early thirties at Asbestos P.Q. and our second in the forties at Thetford Mines P.Q. our consultants and advisors to same havinghaving been the Saranac Laboratory at Trudeau U.S.A. under the direction of Doctor Leroy U. Gardner the eminent pathologist and pioneer in industrial health professor Anthony J. Lanza New York University professor J. A. Vidal the Canadian pneumologist Whilst this association did not and still does not believe that asbestos problems threaten the general public it being felt that same are rather occupational and not environmental we could not but see that in our first line of duty did rest one avenue it seemed to us only one that could lead to a sound and thorough quest into the possible causes and ways of redress in such a situation such avenue being the enlisting of a competent team the members of which would investigate advise recommend and SET IN a MOTION research a worldwide plan plan of scientific This ambitious scheme we hope we may be able to achieve with such guidance as that of the Institute of Occupational and Environmental Health scientific committee under the rigorous and enlightened direction of Dr. George Wright an authority in Labour Medicine and a foremost pioneer on this continent in the field of physiology Our chrysotile mines in Canada being responsible for some 85 of the world chrysotile mining production USSR excepted we could not however avoid the pursuit of research in those fields beyond mining and milling proper and we just had to embark into the fields adjunct such as manufacturing processing and uses even if our responsibility as such was not entailed for that use made of our fibre outside of the mines and mills It is thus that our Association became involved in those other fields manufacturing processing uses etc. In so doing we knew we would have to face problems which do not seem to exist in our mining operations for instance the problem of mesothelioma a problem which virtually does not exist according to our Clinic records thus no mesothelioma verified as such has appeared with us since 1960 and only four had appeared before 1960 two of which raising serious doubts as to their authenticity having not been we feel effectively investigated It is with pride confidence that we submit to your good consideration this present study 6 INTRODUCTION We shall ever be most appreciative and thankful for the generous assistance and courtesy already extended to us in the preparation work and study which lead to the present scientific endeavour of the committee of the Institute under Dr. Wright and we would address our- selves particularly to those distinguished institutions which participated to the two Antigua Conference meeting the Pneumoconiosis Research Unit Penarth Wales the United States Public Health Services the Industrial Hygiene Foundation at Pittsburgh the Labour Medicine School at Milano the Mount Sinai Occupational Sciences Laboratory at New York the American Cancer Society the Industrial Health Institute at Helsinki and the many scientists of England Canada South Africa France Federal Republic of Germany USSR East Germany who have so generously contributed with their knowledge advice and data Karl V. Lindell E.M. D.Sc. President of Quebec Asbestos Mining Association and Chairman of the Executive Committee of the Institute of Occupational and Environmental Health Iran Sabourin Q.C. Counsel of Quebec Asbestos Mining Association and Secretary of the Executive Committee of Institute of Occupational and Environmental Health a 7 INTRODUCTION It has been known for nearly half a century that men employed in the production and use of asbestos fibre were under circumstances of pro- longed and intense exposure liable to the development of a diffuse and at times fatal degree of lung fibrosis Recognizing this responsible components of industry instituted methods for reducing the concentration of asbestos fibre in the ambient air of the worker with a consequent lessening of the frequency and severity of pulmo nary fibrosis in those exposed Recent observations quite strongly indicate that even more stringent protection of the worker is needed in many situations if the problem of pulmonary fibrosis is to be entirely eliminated During the past twenty years it has been convincingly demonstrated that under some but not all circumstances of human exposure to the inhalation of asbestos fibre the frequency of occurrence of lung cancer bronchogenic cancer is higher than that expected in a similar but nonexposed population This relationship in a way similar to that with pulmonary fibrosis appears to be dose and time dependent In the very recent past there appears to have been demonstrated an epidemiologic relationship be- tween the exposure of persons to substantial amounts of crocidolite asbestos and subsequent development of pleura and peritoneal mesothe- lioma a fatal form of cancer in most instances The role of chrysotile amosite and anthophylite asbestos in this regard is still moot as is also the question of dose and time relationship between exposure and the occurrence of mesothelioma Although it is a fact that the incidence of lung cancer and mesothelioma is higher in those who inhale substantial amounts of asbestos fibre than it is in the exposed population the precise role of fibre in this relationship is still uncertain Evidence suggests that one or more factors such as cigarette smoking must exist with fibre before the development of lung cancer is aug- mented Less is known with respect to such a carcinogen action in the relationship between asbestos fibre and mesothelioma The asbestos related industries at one time con- cerned only with preventing pulmonary fibrosis are now faced with additional biological hazards associated with the fibre The options available to the industry are apparent ) The production of this very useful material could be abandoned either voluntarily or by law 2 Users of the fibre might minimize their responsibility by adopting substitutes of lesser biological activity 3 If the precise nature of the injurious action of the fibre could be learned it is conceivable that the fibre might be altered to remove this effect while retaining the desirable qualities of the fibre None of these options are attractive or appear to be immediately feasible The remaining option is the one that industry has followed in the past and would likely find the most acceptable for the future With the realiza- tion that asbestos fibre in sufficient concentration to produce tissue injury has and continues to exist in various operations it becomes evident that we must determine what exposure patterns can be tolerated without the production of disease and adopt engineering methods capable of reducing the concentration to that which is consistent with good health throughout the life of persons who might be thus exposed This objective must be achieved if the industrial use of asbestos fibre is to continue An additional objective less directly related to safe utilization of asbestos fibre is to learn how to manage the future of those persons who have already sustained a substantial exposure to the inhalation of these fibres For example should those persons who have had a known category of fibre exposure but have not as yet developed evidences of disease be removed entirely and forever from further exposure If so how are these persons to be identified These two queries also can be applied to those persons now exhi- - biting evidence of biological effects of asbestos fibre Is there reason to hope that removal from further exposure will prevent the disease or its progression once a certain level of exposure has been reached Such queries and others of equal pertinence can be answered only by comprehensive properly designed studies of the natural history of the biological effects of asbestos fibre The combined medical legal and sociologic management of persons already exposed to asbestos fibre is dependent upon the information which can be gleaned from such studies The factors discussed in Sections I and II of the follow- ing find their paramount importance as applicable to these two objectives There are those who believe that since the use of asbestos fibre saves lives some risk to life in its production and use is acceptable This compromise is not reasonable or necessary Materials possessing more potential for injury than does asbestos are now being handled with greater safety than is asbestos Examples of these are radiation emitters explosives and beryllium With the cooperation of employer employee and regulating agencies whose actions are based upon adequate knowledge there is no reason to doubt that asbestos fibre can achieve safe utilization Section III of this manuscript aspects of this phase considers some One may wonder why there has been a delay in the development of safe practices for using this material since its potential for fibrogenesis has been known for fifty years and the suspicion that it might play a role in neoplasia dates back to 1935. A paucity of knowledge has been and continues to be the major deterrent for the development of reliable and adequate safeguards This in turn can be traced to several factors to which attention must be directed if the goal of safe utilization of the fibre is to be achieved The lack of study methods possessing sufficient reliability to convince all concerned has been a major deterrent to which considerable but still inadequate attention currently is being directed A paucity of adequately trained persons willing to devote their energies to the problem is a second major deterrent This in part has stemmed from the fact that the number of persons who might become interested in the problem has been diluted by the explosive broadening of the medical scientific horizon Equally at fault is the lack of opportunity for study and insufficient funds for that purpose characteristic of past years There is no reason to expect that these problems will disappear and adequate information be obtained spontaneously without directed effort The indus- tries involved the workers with their organizations and the government regulating agencies either directly or indirectly might be expected to provide the opportunities for study and the funds for this purpose Past experience of Government agencies suggests that they have difficulty in mounting an effort that must be sustained over several years and it is doubtful that the workers and their organizations can do so on a broad enough scale This places the burden of developing the necessary information and putting into operation the required safeguards directly upon the shoulders of the industries involved The desired information categories These are falls into four major 1. Studies dealing with a maximum allowable concentration of asbestos fibre in the envi- ronment of man 2. Studies dealing with the determinants and mechanisms of the biological action of asbestos fibre 3. 3. Studies dealing with reducing the concen- tration and numbers of inhaled asbestos fibres 4. Studies dealing with the development and evaluation of methods used in the preceding considerations The material which follows proposes a systematic program for studying the problem in such a way as to provide the necessary information for the purposes set forth above It is obvious that the - 10 - categories are related and that there is some overlapping and reduplication There is nothing that has not been expressed before but it seems that a useful purpose might be served if the areas for study are recorded so that memories can be constantly refreshed and none of the important factors overlooked Just how this material will be used is not entirely clear at the moment It can act as a scaffolding upon which eniisted research can be structured It may assist in minimizing overlap and reduplication It is hoped that it may assist those who are designing pertinent studies to include the necessary components It may also help to indicate the areas of study which would be the most productive in terms of a speedy development of safeguards It should give an understanding of the size of the problem and hence avoid the staging of inadequate attacks The outline may also assist in developing an orderly approach and thus reduce the chance that efforts will be dissipated by popular interests It is apparent too from such an outline that the several major avenues can be worked upon simultaneously and each component will benefit by integration of effort The time appears to have come for a concerted approach and a vigorous pursuit of the problem -- SECTION I 1 12 : Studies DealingDealing with The Maximum Allowable Concentration MAC of Asbestos Fibre in The Environment of Man Here we are concerned with solving the essential question of what level of fiber concentration can be tolerated over one's entire life span without causing illness under those various circumstances of operation where man is exposed The direct approach to the solution is by contrasting in terms of the total character of exposure two distinct populations the one evidencing illness reasonably incriminating asbestos fibre and the other free of such evidences The kind of exposure tolerated by the specific illness free population is the one which must be achieved and maintained The MAC for asbestos that has been followed in the U.S.A. during the past twenty years was Jesigned to protect the worker against the development of pulmonary fibrosis and its sequelae It had its data basis in the study of Sayers and Dreessen which was not proposed at the time as authoritative.nd authoritative.nd was used rather as a tentative measure It is not surprising that their study of persons exposed for less than fifteen years and whose environmental description utilized methods now known to be inadequate should prove to supply an MAC which we have every reason to question seriously at this time Moreover we now have evidence that in addition to causing pulmonary fibrosis asbestos fibre plays a role in pulmonary carcinogenesis and mesothelioma - conditions for which the current MAC made no allowance whatsoever It can be said with little fear of contradiction that nowhere does there exist a body of scientifically sound data concerning the incidence of asbestos related disease arising out of a lifetime of employment in an adequately described environment Hence we have no ability to establish now a proven MAC for any single much less for the multiple varied types of employment utilizing asbestos fibre Reminiscent of the action of twenty years ago a proposal is now being made as to a safe limit based on fibre count per cc Admittedly this is tentative but unfortunately again it is based on scant direct plus much indirect data from a small number of persons in a single type of employment It is based also on the unproven assumption that the length of fibre to be counted is the one that causes disease while other lengths of fibre do not While it may be prudent at this time to revise the MAC to a different value the inescapable conclusion remains that properly designed studies of populations and environments adequately characterized must be started now so that twentyfive years hence we will at least have moved on a scientific basis from the position we currently occupy Because the kinds of fibre used vary as to nature and size and because coexisting materials present as airborne contaminants may vary greatly in different circumstances of employment it is essen- tial that the MAC be established for each of the broad categories of human exposure to fibre The major sites of potential exposures to asbestos fibre are 1. Fibre production exemplified by mining milling refining conditioning packaging and shipping II Manufacturing products composed entirely or in part of one or more varieties of asbestos fibre The major manufacturing users of fibre can be classified as textiles friction materials asbestos cement pro- ducts insulation building materials floor covering fillers in many products of diverse character Approximately 250 kinds of manufactured products utilize asbestos III Appliers or assemblers of asbestos or products containing asbestos In this cate- gory are insulation workers carpenters 13 plumbers electricians pipe fitters and a large number of additional and commonly unrecognized operations dealing with asbestos fibre In some instances removal of previously installed asbestos or asbestoscontaining products constitutes the source of a recognized exposure IV Solid waste disposal affords a potential exposure because of the subsequent use for other purposes of bags previously containing fibre and also because of the use of rejected material such as asbestos cement products as land fill or for roads or for other surface construction V. Public exposure may occur via several mechanisms The processes involved in production of fibre and in the manufacture and use of materials containing asbestos may disseminate fibres which are subse- quently carried via air currents into the neighborhood where adjacent workers may be involved or into more distant adjacent areas which may be occupied by residents or by other workers not directly involved in the plant giving rise to the fibre dissemination The solid waste disposal of materials containing fibres may also act as a source of public exposure Workers exposed to fibre in the course of their occupation may bring it home on clothing and thus expose members of their family including children at a very young age and thus expose the public at distances quite far removed from the site of origin of the fibre The use of talcum powders containing easily disseminated fibres of asbestos causes exposure throughout the life span With regard to the requirements for an adequate MAC it is likely that such a limit may be different not only for specific kinds of exposure pattern as suggested in the foregoing but also for different kinds of fibre and proportions in a mixture thereof The inherent structure of asbestos fibre in its various forms its length and diameter and contaminants or coexisting potentially injuri ous agents may cause one environment to be more or less injurious than another For purposes of learning the biologic MAC of each kind of fibre exposures limited to one variety of material will be required These would most likely be found in a fibre production environment Since mixed exposures are common and asbestos plus other biologically active agents coexist in some types of exposure it will be necessary to study examples of these variations of exposure in order to set a meaningful MAC for each such class of operations The studies required for establishing the MAC of a specific environment will of necessity be of an epidemiologic character embracing various categories of exposure and will look at the role of asbestos fibre as it is related to neoplasia and to tissue injury and consequent alterations Recognition of the biological end result of exposure to fibre poses difficulties both qualitative and quantitative but with sufficient effort and care it appears reasonably possible Evaluation of the exposure in terms of quality and quantity is much more difficult even at present let alone in those periods of the past 25-30 years which are so essential to our understanding of the import of biological end results of the present This seemingly insurmountable task may delay arrival at a reliable MAC but should not deter us from our task We possess even now exposure data which can be useful for our purposes though with no pretense of desired accuracy If contem- porary data can be obtained on a broad scale it will be found very useful at a later date An outline of desired information pertinent to establishing a reliable MAC follows No single study is apt to embrace all of the factors noted 14 I. Fibre Production A. Chrysotile 1. Mining a Nature of exposure ) Duration and lapse time 2 Class of fibre 3 Fibre count 4 Fibre size pattern ) Material adherent to fibre - trace metals - Waxes etc. 6 Coexisting particles 7 Coexisting carcinogens 8 Smoking history 9 Hobbies or homework or second job b Recognition of tissue reaction ) Pulmonary physiology 2 Roentgenogram 3 Clinical 4 Biopsy 5 Autopsy 6 Ferruginous bodies c Type of tissue reaction ) Inflammation and granuloma 2 Fibrosis 3 Pleura plaque 4 Bronchogenic cancer 5 Mesothelioma 6 Gastrointestinal 7 Chronic bronchitis d Nature of population ) Case studies - retrospective and prospective ) Current employees -- one time survey ) Cohort retrospective and prospective 2. Milling and shipping a - as under mining B. Amosite C. Crocidolite D. Anthophylite E. Asbestos like materials talc tremolite Wollastonite brucite Study B C D and E by scheme for A II Manufacturing ad ad as under mining for Textiles Insulation Brake lining Asbestos cement products Floor tile Roofing Building materials III Appliers assemblers and users 3 as under mining for Insulation workers Plumbers Steam fitters Ship builders Carpenters IV Solid waste disposal neighborhood - workers and residents V. family of workers exposed resident neighbors of plants and solid waste disposal general public water talcum powder Study IV and V by d under mining The following outline lists the individuals actively engaged in studies directed towards determining the maximum allowable concentrations of asbestos fibre in the environment of man We are confident that others as yet unknown to us are working in this area and regret that they are not included The abbreviations appendix II indicate the nature of evidence under study In appendix I further details of each study will be found Immediately following the outline of work in progress is an analysis of the relative need for initiating new or additional studies 15 - STUDIES DEALING WITH MAXIMUM ALLOWABLE CONCENTRATIONS OF ASBESTOS FIBRE IN THE ENVIRONMENT OF MAN 1. Fibre Production Mining and Milling Pure exposure A. Chrysotile McDonald Can -- pf.pp.dc Vigliani Vigliani It WAT me Zolov Bu - fb.pp Webster S. Afr - fb.pp Cremer S. Afr - di B. Crocidolite McNulty Australia - pp Webster S. Afr me Cremer S. Afr - pf C. Amosite Webster S. Afr - me.fb pp Cremer S. Afr pf Anthophylite D. Anthophylite Noro Fin - me Kaski Fin - me Meurman Fin - me Buminovich SU - pf E.E. Talc Kleinfeld KleinfeldKleinfeld US - me F. Other fb Kacnelson SU mixed mixed exp ZoloZovlov Bu SU mixed exp. fb.pp.pf II Manufacturing A. Textiles Cralley US US me Mancuso US - me Enterline US - me Wolfsic US - pf Newhouse GBbc GBbc pp.dc Hunt GB - pf Lewinsohn GB pf Avril F - me Navratil Cz - me Enterline US - J.M - retiree other Bristol US M - ray fb Anspach EG - me Bohlig WG - me Ashcroft GB me Roach GB f ~ b Kacnelson SU - fb Einbrodt WG - ab B. Insulation Cralley US - bc me Enterline US - M - retiree fb.me BristUo S l- JMx M- r-ay fb Bristol C. Brakelining Cralley US - me pf.pp Enterline US - M - retiree other Bristol US Mx Mx ray fb D. Asbestos Cement Lepoutre Bbc Bbc me Navratil Czbc Czbc me Enterline US - J.M - retiree other Bristol US - M ray fb E. Floor tile F. Roofing G. Building material Cralley US - fb.pf Enterline US - me Enterline US - M- M- retiree other M- Bristol Bristol US J ray fb of H. Unknown type of fibre and mfg Linell Sw -- me Appliers III Appliers Vigliani It - me Selikoff US - fb.pf.fb.pfp.ppfbp.pf.pp Balzer US - dc.gi Kleinfeld US - me gi Harries GB - me Sheers GB me Neighboring workers Elmes Sturm GB - me pf pp Stumphius Ne - me Cowle Can - me IV Solid Waste Disposal V. Public Exposure Selikoff US - ab Selikoff US - me amosite neighborhood Harries GB - me Wagner GB - me Wells GBbc GBbc me important if being done Bell GB - ab Gibson GB me McDonald Can - me Cartier Can me neighborhood Saucier Canab Canab Canab animals Avril Fab Fab Fab Roitzsch EG -- me Burilkov Bubc Bubc tbc Cooper US - me _ - Selikoff US me Smith GB pp.fb Nottingham ab US talcum powder Cralley Noro Findc FindFincdc Findc Kotin US North Carolina pp Bohlig WG - me Ashcroft GB- GB- me Zolov Bu - pp Kaski Fin - pp Linell Sw - me - 16 - Comments 1. It would appear that the exposures to pure chrysotile and anthophyllite currently are being looked at in sufficient depth to make the maximum use of data derivable from past exposures Some serious thought of course should be given to making certain that data for the future will be obtained properly In this respect we think mostly of proper environmental hygiene studies and methods ade quate to recognize the biological aspects of fibre in humans Membrane filter collection and fibre counting will be needed Personal medical follow up of cohorts with accurate knowledge of what diseases develop and autopsy confirmation must be provided We need to look into the question of whether or not anyone is obtaining the desired information with respect to crocidolite and amosite and talc The first two of these are being used in con junction with chrysotile and probably with anthophyllite It might be added that tale is not only being used in conjunction with asbestos fibres but also may be creating situations in the absence of asbestos exposure for which asbestos might be blamed if one utilizes ferruginous bodies or pleura plaques as the marker for previous asbestos ex- posure . While it is true that quite a few names appear under studies in Manufacturing it should be pointed out that some are of rather limited utility for determining a proper MAC The studies of Mancuso Enterline Wolfsie Avril and Navratil lack industrial hygiene data The studies of Cralley may have considerable utility because he does have some industrial hygiene data but the medical studies remain to be done The two JohnsManville epidemiologic studies Enterline and Bristol may ultimately develop into usable information but at this point should be considered predominantly as exploratory studies to set the stage for later more specific studies The studies of Newhouse Hunt and Lewinsohn successor to Knox should lead to quite useful data It can be readily seen that information regarding insulation brakelining asbestos cement floor tile roofing and building material is almost devoid of specific approach at this time In this category we need the following ) A study of available cohorts in each type of manufacturing going back as far as there are usable records and where data is not available in the records of respect to the cause of death the company with an effort should be made to do this through Social Security data 2 Truly prospective studies with direct follow to the time of death should be set up and pursued in ) populations going back as far as we still have appreciable numbers of living members b employees who have begun work after known improvements in industrial hygiene ) employees now being started With respect to these groups we should have adequate data concerning their total employment and hobbies clinical histories and smoking records physical examinations chest films sputum for ferruginous bodies appropriate pulmonary function tests and adequate data concerning the environment to which there has been exposure This study should also include every effort to look at the progression in those who have been removed from exposure and also the question of regression These studies need to be done in 1. A textile exposure 2. Insulation manufacturing 3. Asbestos cement products 4. Brakelining - especially personnel used in testing 5. Building material 6. Floor tile 7. Roofing Every effort should be made to try to make these studies in populations where there is relatively little crossover of type of employment involving asbestos exposure Of these groups floor tile and roofing might be delayed until information from the M Bristol study is finished III With respect to stimulating and pursuing studies in the group of appliers of asbestos products there would appear to be a rather intensive effort in this direction at this time by various groups This research should be encouraged by any means at our disposal It is apparent that the question of what concentration and type of fibre the applicators are exposed to should be studied in detail The importance of learning what kinds and con- centrations of substances other than asbestos the insulation workers may be exposed to is also of paramount importance IV Insofar as we can determine no one is specifically directing attention to solid waste disposal other than what each specific industrial plant or operation is doing These efforts range all the way from burying the material at sea or bulldozing it under- t? ground to using it for paving of roads and parking lots V. There are numerous investigators looking into the question of public exposure but for the most part they look at only one feature namely the presence of asbestos bodies or the frequency of mesothelioma in populations not classed as workers in the asbestosusing industries The weakest part of the program relating to public exposure would appear to be the absence of knowledge with regard to the presence and numbers of asbestos fibres in the ambient air near building projects asbestos industry plants solid waste disposal depots and the city streets or farmers fields There can be little question of the importance of this part of the overall program and it would seem that the hang has to do with the questions of accuracy and the feasibility of making such studies The U.S. Public Health Service considers asbestos to be a pollutant of second importance ozone SO and oxidants are of primary importance at this moment and they will perhaps do something about the question of asbestos in about two years It would seem that along with the development of adequate methods of plant industrial hygiene monitoring some extra dollars from a pooled re- source might be used to encourage the personnel of industry to make some outside studies We would think the desirability of this is beyond question and the feasibility from several aspects should be looked into 18 SECTION II Toe emrhae ne foe - 19 - Studies Dealing with The Determinants and Mechanisms of The Biological Action of Asbestos Fibre In addition to of such studies of a practical effort to learn the easily appreciated contribution to science there are cogent reasons nature for a vigorous sustained all that we can about the mecha- nisms whereby asbestos fibre may cause disease There are reasons to believe that at this moment there are persons who have had exposure in the past years sufficient to cause illness at some time in the future even though further exposure now is reduced to a safe limit Although one cannot be too optimistic there is the hope that new knowledge might provide the key to interrupting the process in such persons Another reason is to be found in the fact that from an exposed population some develop evid- ences of illness attributable to asbestos fibre whereas workers exposed in a similar manner over the same interval of time remain free of evidences of injury Unevenness of exposure among the population and variations between individuals as to the amount of fibre retained may be important factors The possibility of a variation between individuals with respect to ussuc sensitivity may also play a role In any event the answer to this riddle would bear upon methods for prevention of injury Still another reason for such studies will also bear upon preventive methods It is customary to think of reducing or interrupting all contact with a potentially hazardous agent as being the chief or only method of preventing injury It is conceiv- able however that alteration of the agent in such a manner as to convert it to a injurious one might be achieved Examples of this occurred in the use of lead compounds in the pottery industry One might also alter the host the method of vaccination being an elegant though not entirely appropriate example The factors determining the relationship between the physical and chemical nature of an agent and its potential to cause tissue injury are complex Among these relationships one can see the relevance of the following Intensity and duration of contact with tissue are important factors in determining the effect of an agent on the tissue For this reason the biological dynamics of asbestos fibre with respect to its deposition removal and transfer or storage within the body needs thorough study For a biological reaction to occur the individual cells of the tissue both fixed and mobile are the basis of the reaction In addition via humoral mechanisms reaction in a more distant portion of the tissues may occur For these reasons the intimate details of the way in which indi vidual cells react to asbestos fibre deserve the most thorough study In addition to reacting individually the cells also act in a more organized fashion and express this in what might be termed a tissue reaction Virtually all of the ways in which tissue can react is known to occur in response to asbestos fibre These include inflam- mation and granuloma formation fibrogenesis or scar formation and neoplastic reaction It is pos- sible also that asbestos fibre influences the immu- nological state of the body both locally and in a more general way Much has been learned about these reactions from a study of human tissue but for obvious reasons this kind of approach to the overall problem is somewhat limited because one lacks the ability to manipulate the conditions under rather controlled requirements Because of this extensive work utilizing animal models will be required as well as a continuation and more detailed study of human material Our attention should not be directed entirely to the host's reaction to the fibre To understand the cellular reactions one must also consider asbestos fibre as being of a highly diverse character with respect to its chemical and physical makeup and 20 - as to materials which may be adsorbed or bound to The fact that in all sorts of human exposures to asbestos fibre there exists an opportunity for simultaneous exposure to other materials which may influence the fibre or vice versa in a peculiar way so as to vary its biological potential further complicates the entire problem For these reasons the simple term asbestos exposure or asbestos worker is a colossal oversimplification and leads to confusion rather than enlightenment The enormity of the task required for full understanding of the biological effects of this unusual material as it is actually utilized in world affairs staggers the imagination and tends to paralyze one's will to embark upon the effort It is probable however that a full understanding of all aspects of the total problem are not actually required in order to develop the safe utilization of this important material and the enormity of the task should in no way interfere with our pursuit of the matter An outime of some of the approaches to this part of the total problem follows That it is only a partial development will of course be obvious - 21 - I. Biological dynamics of asbestos fibre A. Deposition 1. Anatomical location 2. Effect upon cilliary apparatus* 3. Effect upon macrophages B. Removal 1. Bulk removal 2. cilliary mechanism rapid removal 3. Macrophages slow removal -- transfer- transfer- storage 4. Chemical reaction 5. Influence of various agents and conditions upon the removal mechanism C. Transfer and storage of fibre within the body 1. Location in organs and tissues 2. Recirculation of fibres 3 Influence of various agents and conditions upon this mechanism D. Influence of alteration of asbestos fibre upon its biological dynamics e Asbestos as a tool to study carcinogenesis 1. Effect of altering fibre upon the reaction g Effect of altering host cancer prone animals animals altered by radiation or by hosting an- other cancer 2. 2. Mesothelioma : a Anatomical location b Pathways of fibre transport* c Association etc. as in b above d Association etc. as in c above e Dose and time lapse f Asbestos etc. as in e above g Effect of altering fibre upon the reaction 3. 3. Gastrointestinal* a Why not manifested in experimental animal b Pathway and dynamics of fibre transport in GI system c Is fibre altered in some way by chemical reaction in GI system so that it behaves differently than it does in the lung II Biological reaction of tissue to asbestos fibre III Biological reaction of cells to asbestos fibre A. Inflammation and granuloma 1. Anatomical location A. Mechanism of fibre handling 1. Cells in vivo in situ 2. Reversibility 2. Cell culture 3. Dose patterns and time lapse 4. Influence of other agents upon the reaction PVPO steroids - infection - gases - etc. 5. Effect or altering fibre upon the tissue reaction B. Fibrogenesis 1. Anatomical location where in parenchyma pleura - peritoneum why not lymph nodes 2. Mechanism of formation macrophages - fibro- blasts mechanical - chemical - immunologic 3. Reversibility 4. Time and pattern sequence related to inflammation 3. Isolated cells B. Reaction of cells to fibre 1. mitosis isolated cell culture in situ 2. mitosis isolated cell culture in situ 3. Chemical alterations isolated cell culture in situ C. Immunologic reactions 1. Immediate 2. Delayed 3. Competent 11 incompetent animal D. Reaction of cells from other than mammals 5. Dose and time lapse 6. Influence of other agents to prevent arrest or reverse process 7. Effect of altering fibre upon tissue reaction C. Neoplasm 1. Bronchogenic cancer and metaplasia a Anatomical location b Association with other inanifestations of asbestos exposure ferruginous bodies - fibrosis plaques - etc. IV Physical and Chemical aspects of asbestos fibre which may influence its biological activity A. Oils and waxes B. Other carcinogens C. Properties for adsorption of pertinent materials D. Rigidity E. Divisibility F. Surface c Association with agents other than asbestos d Dose and time lapse * Possibility of different effects being caused by specific kind , physical nature or contaminants of fibre must be considered The following outline lists the individuals actively engaged in studies dealing with the determinants and mechanisms of the biological action of asbestos fibre We are confident that others as yet unknown to us are working in this area and regret that they are not mcluded The abbreviations appendix II indicate the nature of evidence under study In appendix I further details of each study will be found Immediately following the outline of work in progress is an analysis of the relative need for initiating new or additional studies ty i] STUDIES DEALING WITH THE DETERMINANTS AND MECHANISMS OF THE BIOLOGICAL ACTION OF ASBESTOS FIBRE 1. Biological Dynamics of Asbestos Fibre A. Deposition Timbrell GB mo LeBouffant F - mo B. Removal Thomson GB cl C. Transfer and Storage Timbrell GB fsb fsr Botham GB - ab Reimann US - gi Swinburne GB - gi Holmes GB - radioactive asbestos Rubnitz US - gi D. Influence of alteration of fibre II Biological Reaction of tissue to a fibre A. Inflammation & Granuloma Holt GB - fb P.204 Webster SA - fibre length Monkey Klosterk^tterWG - fibre length P.204 Dumont Ca B Pouch Schlipk^terWG EDTA Jacob EG b-ronchoscopy Friberg Sw Helsinki Fin Go dstein S. Afr ab B. Fibrogenesis McIver US - ab dogs Leathart GB pf steroids Szymczykiewicz Po - fsb Kogan SU - fb Zwi S. Afr - pf C. Br Cancer & Metaplasia Stanton US - in McIver US - in dogs Wagner GB - in brucite Smith US in Melver US - cc Peacock GB - in fowl Gross US PMLG cc Wagner GB - in D. Mesothelioma Stanton US - in Graham US - in ovary Massey Cain Cain Cain Smith US - cc McIver US in dogs Wagner GB - in Schm^/hlWG - in long fibre Davis GB in E. Gastrointestinal Spjut US - cc F. Pleural Plaques Irmsher EG - calcification III Biological reactions of cells to asbestos fibre A. Mechanism of fibre handling Botham GB ab B. Reaction of cells to fibre Suzuki US - la Pernis Itma Itma Itma size & kinds of a Allison GB - ma Davis GB - -- Barrett GB- GB- ma seruum Szymczykiewicz Po - fsb Harrington GB -- ma a & sil Holt GB - fb P.204 ab C. Immunologic reactions Szymczykiewicz Po - fsb Warwick GB MA Human D. Chemical alteration of lung Dodgson GB E. Reaction of cells from other than mammals IV Physical and chemical aspects of fibre relative to biological activity A. Oils and waxes Gibbs et al Can - CC B. carcinogens Crailey US Bindrand trace metals Smith US - Benzopyrene Hammond US - cigarettes Stanton US -- methylcholanthrene Wehner US - cigarettes C. Adsorption D. Rigidity Massey Can Q in E. Divisibility F. Surface G. Trace Metals M Research Inst Michailova Bu - V. Non or altered asbestos fibres Gross US - fb absynthetic absynthetic absynthetic C. Gross US - fb - brakedrum dust Gross US - ab - other materials Wagner GB - in neoplasia brucite Davis GB me - 23 Comments A survey of the number of individuals working in this general area reveals a disappointingly small number In addition it can be safely assumed that a good pro- portion of those who do work in this area have other responsibilities and additional interests If we are to obtain the needed information we will have to en- courage and promote specific research studies in this general area With respect to studying the determinants of biological action we urge the pursuit of practical questions the study of which would come under one or more of the areas indicated in the outline These are as follows 1. The question of just what length of fibre causes the biological reaction remains unanswered Is there an innocuous length of fibre Current recommendations for MAC propose counting only fibres greater than 5 microns in length Those shorter than this are lumped with particies Are we in fact monitoring the proper and specific agent for this general problem Insofar as we know the definite study with respect to fibre length remains to be done even though several studies do exist suggesting that only fibres greater than 5 microns in length are biologically active The practical practical questions of removing workers from exposure and other medical considerations hinges on a determination of whether or not biological reactions to asbestos progress remain static or are reversible after cessation of exposure Small bits of information gleaned from studies having other purposes are at times cited in this regard but insofar as we know there has been no systematic study of this question 3. 3. In a vein similar to item 2 there is the question of whether or not there is a dose of specific asbestos fibre which can be tolerated with safety or which can be tolerated with no recognizable reaction The question might be raised as to whether or not there is a critical mass needed in order for biological reaction of recognizable degree to occur It is recognized of course that the definition of biological reaction would determine how one might try to answer this question Nevertheless in terms of those matters of significance to human beings namely granuloma fibrosis and malignancy the problem should be explored There is a strong suggestion of species vari- ation of response to some kinds of irritant and the question can be raised as to whether or not asbestos is one of this type of irritant If there is an species variation can a method be designed to determine in advance those individual members who will respond and those who will not This is a very practical question in employment 5. There is very little being done about the biological dynamics of fibre the studies having thus far been confined almost solely to mathematical models A substantial amount of work with respect to bio logical dynamics of fibrous materials is cur- rently in progress and it is worth considering that we might encourage these groups to add fibres to their study The AEC has interest in this and perhaps those working on that problem might add fibres of various kinds to their studies Information of this kind would go towards answering the question of whether or not there is an innocuous length of fibre The strange story of pleural plaques might be further clucidated by such studies 6. Closely allied to 5 is the question of the fate of asbestos fibre after it has been lodged in the lung Does it persist indefinitely and what are the quan- titative aspects of this Some promote the concept that every fibre which enters the lung stays there and persists forever and thus it becomes of in- creasing importance to know whether or not this is true 7. While there is an increasing amount of information concerning the role of inorganic materials as carcinogens it has been disappointing There has been insufficient interest in such studies The genuine possibility that trace metals associated with asbestos fibre play a strong role in carcinogenesis almost demands that the role of these metals unaccompanied by other agents be completely explored and this should be supported 8. The clinical data suggests in an overwhelming way that cigarette smoking plays a very dominant role in the increased frequency of bronchogenic cancer among those heavily exposed to asbestos fibre The quantitative aspects of this could very well be ex plored in the experimental animal A new technique developed by Battelle at the Hanford Complex might be employed in this regard 9. The fate of ingested chrysotile and other types of asbestos fibre is almost totally unexplored Pundsack believes that the gastric juice has a sufficiently high pH to dissolve chrysotile The transit time would 24 of course play a considerable role The quantitative aspects of this problem are approachable and should be encouraged 10. The use of ferruginous bodies as a marker for both public and industrial exposure to asbestos fibre is prone to all manner of immoderate state ments because we have relatively little reliable quantitative data with respect to these objects and their relationship to biological reaction in tissue A full exploration not only of the relationship between the total of ferruginous bodies and the biological reaction but also with respect to the number of ferruginous bodies arising out of known quantitative exposures and also the question of destruction and removal of bodies is quite urgently needed 11. The role of the physical aspects of fibre in fibrogenesis and malignancy is being explored to some degree but probably not to a sufficiently intensive degree for the importance of the question 12. As long as pleural plaques are as great a mystery as they are with respect to their formation and the paucity of asbestos fibres associated with them plus the fact that the plaques are primarily in the parietal pleura there will be great difficulty in determining the significance of these structures with respect to past exposures and the future develop- ments Can these structures be examined in the experimental animal To do so would be very useful since in man our only chance is to see the end stage and not the developmental processes 13. There are a host of general problems of a somewhat less directly applied nature but which may be even more important from the point of view of their indirect application These are too numerous to list The listing of the above problems should in no way be interpreted as minimizing the importance of the many other problems that could be suggested for study The purpose in listing the above was to indicate at this very moment there are numerous directly applicable studies of an almost pragmatic nature that need pursuit In fact the direct applicability might suggest that they are somewhat pedestrian and therefore are not as desirable for spontaneous study by scientists Efforts to over- come this will need to be made SECTION III i 26 Studies DealingDealing with Reducing the Concentration and Numbers of Inhaled Asbestos Fibres As was pointed out in the first paragraph of the Introduction there is evidence that protection of workers and perhaps of the general public from the potentially injurious effects of asbestos fibre has been inadequate during the past twenty years In Section I it was stated that in part this may be the result of reliance upon an untrustworthy MAC In addition however there can be little doubt but that engineering methods for reducing the airborne fibre concentration have been and remain inadequate both in design and application While some of this may have stemmed from apathy most of it must have arisen from inadequate knowledge with regard to many factors Among these one might list ) Dependence upon methods of counting dust which do not reflect accurately the fibre concentration 2 The untested assumption that generation dispersion and other particle dynamics are the same for fibre and nonfibre particles ) Ignorance of effects of coexisting particles upon the airborne fibre 4 The lack of knowledge concerning the behavior of filters with respect to fibres Factors other than ignorance doubtless contribute to the delay in developing the required degree of protection from airborne fibre Failure of earlier designs to provide the expected suppres- sion of dustiness probably discouraged subsequent efforts embodying newer types of equipment Reluctance to accept alterations in the style of the product consequent to protective measures may also have contributed The persistent use of old equipment and housing which makes dust control difficult to achieve doubtless was a factor The changes in the intimate character of the raw fibre as it left the production site over the past years may also have played a part The manner in which fibre is handled in the manufacturing process especially with regard to the level of energy used in order to augment production may have deter- mined the number of fibres that became airborne The economic influence of competitive materials has been far from a negligible factor All of these things have held back the application of methods which now appear available for the control of airborne fibre One is tempted to predict that with an energetic and unrestricted application of contemporary dust control expertise in the way of complete fibre containment and point source exhaust the inplant and neighborhood dispersal of fibre could be brought to zero per cubic centimeter Whether it is necessary or economically feasible to do so is quite another matter Even if one controls inplant fibre completely there are still the large areas of exposure repre- sented by users and appliers solid waste disposal and public exposure from other sources which are not so amenable to correction One is forced to conclude that studies relating to dust abatment have a high priority The following scheme indicates areas for investigation 27 - I. Information with regard to fibre populations in the actual breathing zone of the exposed person A Fibre production 1. Concentration - duration pattern * 2. Kinds of fibre 3. Physical nature of fibre size 4. Ongin of fibre at BZ rigidity flocs a Unincorporated - pure fibre b Incorporated mixed with or bound to other materials 5. How is borne fibre created 6. Pathway of fibre to BZ B. Manufacture of products 1,2,3,4,5 and 6 as under A. C. Appliers and assemblers of asbestos products 1,2,3,4,5 and 6 as under A. D. Solid waste disposal 1,2,3,4,5 and 6 as under A. F Public 1.2,3,4,5 and 6 as under A. II Aerodynamics of asbestos fibre A. Variations caused by size and shape B. Influence of coexisting material 1. Free materials 2. Attached materials C. Flocculation D Can suppressants be added III Launching or dispersal of fibre A. Effect of way in which energy is applied B. Effect of wetting or compacting agents C. Aerosol with fibre droplet nuclei IV Dynamics of fibre filters V. Methods of reducing borne concentra- tions of fibre While these method will vary according to the circumstances both general fibre production etc. and local pro- old vs new plants etc. there are broad classes of cedures cedures to be used A. Prevention of dispersal 1. Total enclosure from primary bulk handling to finished product - this whenever possible or it only way of doing it 2. Suction ventilation with filter capture of fibre Abolishing exhaust to outside air 3. Packaging a Fibre tight and strong b Automatic handling c Reduce handling d Exhaust with filter capture of fibre e Utilize container that can be incorporated in finished product 4. Reduce local applications of energy 5. Wetting oiling or compacting of fibre not totally enclosed B. Prevention of dispersal 1. All exhaust properly filtered 2. 2. Immediate vacuuming of spills 3. Frequent vacuuming of settled dust 4. Handle processing as carefully as primary 5. 5. Exhaust aerosols droplet nuclei fibre to filters 6. 6. Completely enclosed all transport of fibre C. Dust suppression 1. Humidity droplet nuclei D. Dust dilution 1. Large volume exchange - outside exhaust 2. Large volume with removal of fibre E. Personnel protection 1. Masks a Question effectiveness b Design better ones regarding comfort and vision c Question primary and secondary filters J. More frequent change e Disposable 2. Positive pressure devices a Local or fixed places of work b Mobile or contained 3.3.3. Operator in enclosed booth 4. Change of clothes 5.5. Water repellant clothes - changed and washed 6. Special time schedules for workers eg rotation through jobs of varying exposure regarding limit as to hours per day days weeks years based upon data regarding deposition and removal of fibre and also dose injury relationships obtained in other studies 7. Requirement that workers in certain jobs refrain from exposure to other agents eg cigarette smoking F. Solid waste disposal 1. Handling of filtered material a Plastic containers and buried b Slurry settling ponds - buried 2. Rejects - buried or bonded 3. Used materials eg insulation - buried or bonded The following outline lists the individuals actively engaged in studies dealing with reducing the concentration and number of inhaled asbestos fibres We are confident that others as yet unknown to us are working in this area and regret that they are not included The abbreviations appendix II indicate the nature of evidence under study In appendix I further details of each study will be found Immediately following the outline of work in progress is an analysis of the relative need f^,r.atiating new or additional studies STUDIES DEALING WITH REDUCING THE CONCENTRATION AND NUMBER OF INHALED ASBESTOS FIBRES 1. Fibre populations at breathing zone A. Mining and milling du Toit S. Afr dc B. Manufacturing Holmes GB - tx Kesting WG - tx Muglich EG - tx M US - tx is asb cem build prod production C. Appliers Harries GB - is Selikoff US -- is D. Solid waste disposal Harries GB - is Selikoff US - is E. Public Selikoff US is 11. AerodynamicsAerodynamicsAerodynamics of asbestos fibre III Launching and dispersal of fibre IV Dynamics of fibre filters V. Methods of reducing reducing airborne fibre concentration A. Prevention of dispersal enclosure packaging reduce energy wetting Holmes GB - tx Kesting WG - tx Harries GB -- is M US - tx etc. Selikoff US - is B. Prevent redispersal cleaning filtered exhaust enclose transport M US - tx Selikoff US --- is Holmes GB -- tx C. Dust suppression D. Dust dilution ventilation Holmes GB tx Muglich EG - tx M US - tx etc. Selikoff US - is E. Personnel protection masks clothes time schedules smoking Harries GB - is M US - tx etc. Selikoff US - is F. Solid waste disposal - 29 - Comments While most including member companies of the QAMA of the operating industrial units utilizing asbestos fibre maintain some observation and control of the dustiness at various working places few can be thought of as actually studying the problem For such a purpose precise determination of the concentration and nature of airborne particles in an environment being deliberately manipulated by efforts designed to influence it are required A glance at the outline for III indicates the lack of systematic effort in this regard Our Committee considers no other facet of the asbestos problem to be more important than this one At the same time we not believe ourselves at this moment sufficiently informed and we would like more information and guidance before proposing specific studies in this area With this in mind we plan to enlist the help of one or more experts in this field via either enlargement of our Scientific Committee or by ad hoc consultation After further study we plan specific suggestions We realize that some of the immediately applicable facets of the problem are receiving attention as indicated in outline HI and possibly most of the studies could be done in house by the industry If this mechanism for obtaining the desired information is to be pursued we strongly urge ) the use of personnel for these purposes that have such studies as their only or primary responsibility 2 pooling of resources - personnel equipment sites of study finances - by industries having identical or similar problems We further urge recognition that some facets of this problem would best be pursued outside the industry proper as for example a study of filter dynamics for fibres 30 - SECTION IV - 31 - Studies DealingDealing with Development and Evaluation of Methods in the Preceding Considerations While there is evidence that asbestos fibre can produce pulmonary fibrosis with its sequelae play an undetermined role in pulmonary and mesothe- Hal carcinogenesis is related also to pleural plaques and is the central fibre ..f ferruginous bodies in many instances the quantitative aspects so crucial to the full understanding of these relationships and thus to their prevention :; greatly hampered by inadequate methods of study In some instances the procedures are themselves at fault and in others they have not been applied properly As examples one might mention ) At this time there is no agreement with respect to the criteria upon which a diagnosis of asbestosis is to be made either during life or upon histologic examination of the lungs The same can be said with respect to mesothelioma 2 Conti- nuous measurement of airborne fibre concentra- tion thus giving full meaning to the character of exposure it practical only upon a very limited scale and meaningful data of this kind is virtually absent up to the present 3 Reliable identification of the central fibre in ferruginous bodies is still not possible and obscures our understanding of the meaning of these structures in terms of Public exposure A major and deliberate effort to promote better methods is urgently needed so that as little activity as possible be wasted in compiling further data of questionable value While some of this effort in the direction of methodology will doubtless be made by those directly interested in the problems of the biological effects of asbestos fibre it will likely be necessary to enlist the help of those whose major interest may not be along the lines of biology and fall more nearly in the field of chemistry or physics The following is a list of some of the areas and procedures that need better designed and understood methods of study 32 - I. Characterization of ambient air A. practical method for continuous sampling of airborne fibre concentration at the breathing zone B. A rapid method for sizing the fibres and expressing each as a percentage of the whole C. A rapid and reliable method for identifying asbestos as opposed to other kinds of fibres and also quantitatively differentiating between various kinds of asbestos fibres II Recognition of human exposure to asbestos fibre A. Identification of asbestos bodies as differentiated from other fibrous ferruginous bodies B. Development of a marker which by examination of urine blood sputum or lung tissue would indicate specific asbestos exposure qualitatively and quanti- tatively Can some agent be added to fiber for this purpose? III Recognition of biological effects of asbestos fibre A. Radiologic manifestations of the biologic effects of asbestos 1. ray classification 2. Contrast between exposed and exposed persons with respect to items in ray classification 3. Techniques of radiography for lung and pleura 4. Use of standard films B. Criteria for early recognition of inflammation and fibrosis of lung 1. ray evidence 2. Pulmonary function evidence 3. Histology evidence 4. Can other evidences be obtained from blood urine or sputum C. Criteria for recognition of neoplasia 1. Standards for diagnosis of bronchogenic ca. 2. Standards for bronchial metaplasia 3. Standards for mesothelioma 4. Value to be placed upon cytology studies D. Standards for epidemiologic studies 1. Standard approaches based on retrospective and which prospective methods as to the type of data is required in order to make study worthwhile 2. Relative weight to be given mortality data derived from death certificate hospital records autopsy and also from personal examination during life and its termination 3. Methods of evaluating exposure on the basis of data now extant Can this be done Can a standard procedure be set? The following outline lists the individuals actively engaged in studies dealing with development and evaluation of methods used in the preceding considerations We are confident that others as yet unknown to us are working in this area and regret that they are not included The abbreviations appendix II indicate the nature of evidence under study In appendix 1 further details of each study will be found Immediately following the outline of work in progress is an analysis of the relative need for initiating new or additional studies 33 - STUDIES DEALING WITH DEVELOPMENT AND EVALUATION OF METHODS I. Characterization of ambient air A. Dust Dust samplsamipling ng Addingly GB tx LeBouffant - tx Lynch US - tx Rendall S. Afr mines Mines Chamber of Mines S. Afr mines B. Sizing fibers Keenan US ~~ tx Speil L'S - tx Walter WG - tx C. Identification of fibres Speil US - tx Berkley US - is Swettenham GB - X Heron GB Institute of Occ Health Netherlands Joosting - is Tousimis US Werner EG Grimshaw GB D. Pubi c Eifenberger WG Heron GB II Recognition of human exposure to asbestos fibre A. Identification of fibre Einbrodt WG - ab Swettenham GB Berkley US Netherlands group - Joosting Baden et al US B. Development of marker of exposure Bader US - ab Gold GB - ab quantitative III Recognition of biological effects of asbestos fibre A. Radiology Gilson UICC GB Viikeri Fin - ultrasound Hennig EG - scintigraphy B. Criteria for early recognition of inflammation and fibrosis of the lung Andreeva SU Regan GB - pf Bader US - pf Otto WG - fb & total dust Champeix F- F- pf Galy et al F - pf Worth et al WG BILLAZA pf Stolbun et al SU - pf ballisto C. Criteria for recognition of neoplasia Thomson SA - me Naylor US me Kotin US - mesothelioma registry Webster S. Afr - mesothelioma registry D. Standards for epidemiological studies -y 34 - Comments One of the major deterrents to controlling human exposure to asbestos fibre is the lack of a readily usable method of quantitating and sizing fibre in the air at the breathing level of the worker Current methods are cumbersome and time consuming and do not encourage the desired frequency of sampling at the working place This problem is also faced by others studying industrial and public environments and likely will not be solved by in house efforts Since much of the effort of both sections I and III dealing with maximum allowable concentration is dependent upon a usable method for monitoring dust the importance of this facet of methods can be readily appreciated It seems likely that enough workers are now being attracted to methods for identifying asbestos fibre The desirability of a marker of the presence and quantity of asbestos fibre retained in the body is obvious The measurement of urine lead or porphyrin as a marker of lead retention is an example At this point in time there are no very logical suggestions for a method applicable to asbestos but the matter should be thoroughly explored The possibility of an immunological reaction based upon titre is suggested The use of radiologic evidence to recognize the biological effects of asbestos fibre is receiving adequate effort at this time We now know that the radiologic evidence is not the first or earliest discernable mani- festation of biological activity of asbestos McDonald has confirmed the findings of others that abnormality of oxygen transfer across the alveolar membrane pre- cedes radiologic abnormality This opens the possibility for recognizing reactors and removing them from exposure Further exploration of this in both humans and animals is urged at this time Other efforts to develop methods for earliest recognition of biological reaction to asbestos should be pressed Here too the role of an immunologic response might be explored At this time there appears to be sufficient effort being devoted to criteria for neoplasia especially mesothe- lioma and also the methods of epidemiologic study The problem in this regard is largely that of a failure to apply what is now known | 35 I APPENDIX I SECTION ONE Oe aR re Each item sets forth a resum^' of work in progress For each of the four sections see index the specific project is arranged alphabetically according to the first letter of the last name of the principal investigator - 36