Document R2JO29qVKMoxrZyk2GoaVe7ME

FILE NAME Manville JMA DATE 1966-1967 DOC JMA005 DOCUMENT DESCRIPTION Report - Asbestosis Fact and Fancy with Cover Letters UC Berkeley UNIVERSITY OF CALIFORNIA BERKELEY BENKELEY DAVIS IRVINE * LOS ANGELES * SUVERSIDE SAN DIEGO SAN FRANCISCO 7944N SANTA BARBARA SANTA CRUZ SCHOOL OF PUBLIC HEALTH EARL WARREN HALL BERKELEY CALIFORNIA June 17 1966 94720 W. Clark Cooper M.D. Clinical Professor of Occupational University of California School of Public Health Berkeley California 94720 Medicine Dear Clark for the 19th Annual Meeting of We are writing the preliminary program in San Francisco in February 1967 The paper which the A.A.0.M. to be haelwdillingness to present will appear on the program as you have expressed Fiction and is scheduled for the February 8th Asbestosis Fact and 50 minutes for your paper Scientific Session at 11:10 a.m. We are allotting General will take no more than 30 minutes and hope that your presentation after the paper is presented will be called for immediately Please let me know discussion Dr. Kenneth Smith has been asked to open the discussion if you will require any type of projection equipment I have been asked by Dr. Boucot Sturgis the Chief Editor to inform you is the official journal for that the A.M.A. Archives of Environmental Health a the papers that are presented We would urge you to prepare publishing and submit it to her for publication Also Dr. Jack Schulte manuscript and Fellowship Committee and Member of the Chairman of the Publications to assist the Editorial Board of the Archives has expressed his willingness speakers in the preparation and submission of their manuscripts You will be identified in the list of Scientific Program Participants as follows W. CLARK COOPER M.D. Clinical Professor of Occupational University of California School of Public Health Berkeley California 94720 Medicine We would like the information in the preliminary program to be as precise as possible Could we hear from you regarding its accuracy Best regards Sincerely yours IRT 1s cc Dr. Kenneth Smith Irving R. Tabershaw M.D. Chairman Program Committee 19th Annual Meeting A.A.O.M. an UNIVERSITY OF CALIFORNIA BERKELEY BERKELEY DAVIS IRVINE LOS ANGELES RIVERSIDE SAN DIEGO * SAN FRANCISCO 1744 7 SANTA BARBARA SANTA CRUZ SCHOOL OF PUBLIC HEALTH EARL WARREN HALL BERKELEY CALIFORNIA 94720 June 24 1966 Dr. Kenneth Smith Manville Corporation 22 East 40th Street New York N. Y. 10016 Dear Dr. Smith You can see by the enclosed copy that Dr. W. Clark a paper entitled Asbestosis Fact and Fiction at the Meeting in San Francisco in February Cooper will 19th Annual present A.A.0.M. Approximately 10 minutes will be allotted for a general discussion of each paper Would you be willing to open the discussion of Dr. Cooper's paper by taking 3 to 5 minutes to comment on the pertinence of the subject matter to the practice of occupational medicine Your participation in the program would be appreciated very much Sincerely yours IRT Irving R. Tabershaw M.D. Chairman Program Committee 19th Annual Meeting A.A.O.M. 7944K 7944K July 7 1966 Dr. W. Clark Cooper University of California School of Public Health Earl Warren Hall Berkeley California 94720 Dear Clark I have just received an invitation from Irving Tabershaw to open the discussion of your paper on asbestosis at the A.A.0.M. meeting in San Francisco next February Naturally I accepted with enthusiasm for I shall look forward to learning more about the subject from your presentation I would be very grateful if you could give me a copy of this paper before presentation along with any comments which you would like to make so that I can be prepared to open the discussion along proper lines Incidentally if you could tell me the date and time of our appearance for the presentation it would be appreci- ated On another subject I would like very much to know about your visit to our plants in the Los Angeles area whether or not you were able to visit other companies and how the whole study is progressing in general Please let me know if I can be of any assistance in any way whatsoever with your project Sincerely Kenneth W. Smith M.D. Medical Director _ UNIVERSITY OF CALIFORNIA BERKELEY BERKELEY DAVIS * IRVINE LOS ANGELES RIVERSIDE * SAN DIEGO * SAN FRANCISCO 744474H44H SANTA BARBARA SANTA CRUZ SCHOOL OF PUBLIC HEALTH EARL WARREN HALL BERKELEY CALIFORNIA July 29 1966 94720 Kenneth W. Smith M.D. Medical Director Manville Corporation 22 East 40th Street New York N. Y. 10016 Dear Ken Your letters were here when I returned this week from a brief vacation and the trip to Cincinnati I am pleased that you will be able to participate in discussion at the A.A.0.M. meeting next February and hope that I will be able to develop enough new information to warrant this updated presentation LeRoy Balzer and I had an excellent visit to Southern California three weeks ago when we saw the thermasbestos and fiber glass operations Mr. Paddock and Mr. Robinete at Long Beach and Mr. Rust and Mr. Shelmire at Corona could not have been more friendly and cooperative We learned just what we needed to make our environmental studies and occupational histories in insulating workers more meaningful Our program is slowly getting under way We have reconstructed the population of insulating workers in Local 16 of the Asbestos Workers Union as of and since January 1 1946 them All current members and are attempting to are being interviewed find out what has happened to and examined with one of the major objectives being to obtain information on their working histories and ex- posures to all types of insulating materials whether or not they engaged installed marine insulation handled amosite tore out old insulation etc. We have a good working relationship with both the unions and with the Association of Western Insulating Contractors We have also begun environmental studies first in the local apprentice school and now at two large construction projects I will information other not go into details as to than that we hope to have what will be done with all a longitudinal study based this upon the rather limited information age time of entry into the industry etc. of the men who worked any time between 1946 and 1966. We also hope to set the stage for a prospective longitudinal study based upon the more complete information we are obtaining in our interviews and environmental studies The Seattle Spokane and Portland unions want to be included have been up there and have corre- sponded with also kept in them touch indicating our interest and with Dr. Norwood at Hanford intent to work with them I have and our present schedule will take us into the northwest in September I am also interested as are so many others these days in finding more about the asbestos bodies real or apparent that can be found in lung juice and sputum We are collecting smears and tissue from consecutive autopsies at Dr. Kenneth Smith Page two July 29 1966 San Francisco General Hospital are collecting sputum from a variety of sources and have a number of things we hope to do with the bodies we detect I have located a number of cases in the Bay Area diagnosed as dying with pleural or peritoneal mesothelioma and am attempting to find out 1 the validity of the diagnoses 2 whether or not there has been any pattern of association with asbestos and 3 if there has been a pattern of association what kind I had a good visit with Lewis Cralley last week and am looking forward to following it up with another trip late in August George Wright was out last month Paul Gross is to be in town next Wednesday and Thursday the ray panel for the PHS study will be here September 26 and Cliff Sheckler is also coming out in September Communication is beginning to flourish and when you are next in the Bay Area be sure to call us up and let us arrange to get together With best wishes Sincerely yours ~ : } ro - SN W. Clark Cooper M.D. Research Physician Occupational Health WCC ce Dr. Cralley P.S. Have you seen the diatomite study followup report yet While the version prepared for Vienna is a very brief summary of the full report I think it has been very worthwhile a project and the report is an interesting one if I do say so myself mere August , 1966 Dr. V. Clark Cooper Research Physician Occupational Health University of California Berkeley Earl Narren Hall Berkeley California 94720 Dear Clark 301 Asbestos Survey California Many thanks for sending me your very complete and informative letter concerning this survey I am very pleased to note that your plans for the program are progressing satisfactorily Please remember that if I can be of any help in any way whatsoever do not hesitate to contact ma I expect to be on the Coast some time later this year and will stop in to see you As an adde to n youd r lu ettm er of July 29 you asked ifI had seen a copy of the diatomite study followup report As a matter of fact I have been out of the office for a considerable length of time and find it rather difficult to sort out the mail which has come in As yet I have not seen report and I do not expect to go to Vienna Therefore if you do have a spare copy of the report which I could have I would be very grateful to receive it If you have no spare copies please let me know where I might obtain one Many thanks for all you help Sincerely Kenneth W. Smith H.D. Medical Director UNIVERSITY OF CALIFORNIA BERKELEY BERKELEY . DAVIS IRVINE LOS ANGELES RIVERSIDE * SAN DIEGO SAN FRANCISCO 7944F SANTA BARBARA * SANTA CRUZ SCHOOL OF PUBLIC HEALTH EARL WARREN HALL BERKELEY CALIFORNIA 94720 August 31 1966 Dr. Kenneth W. Smith Medical Director Manville Corporation 22 East 40th Street New York City New York 10016 Dear Ken I do not have a final copy of the diatomite followup report but I believe Lewis Cralley should be able to furnish you one It contains the basic conclusions although space limitation required us to leave out many of the supporting tables I am sure you would like to see them some time I am trying to get the material in shape for publication but other more pressing matters keep getting in the way I had a phone call this afternoon which indicates that Cliff Sheckler and John Gadway will be visiting us on September 16 and we are looking forward to discussing with them our work with insulating workers I hope that we will have a chance to get together some time this fall or winter Best wishes as always Sincerely yours WCC js CC Dr. Cralley W. Clark Cooper M.D. Clinical Professor and Research Physician Occupational Medicine 7944 J Jarmary 16 1967 Dr. W. Clark Cooper University of California Senool of Public Health Berkalay Earl Warren Hall Berkeley California 94720 Dear Clark The time for the A.A.0.M. meeting in SanFrancisco February 8 is approaching rapidly and I must make some travel plans Could you please tell me where and when the meeting will be held as I am not a member of the Academy Also in order to open the discussion intelligently I would appreciate a preliminary copy of your paper or some remarks about whya ou t are goi to sn ayg so I that shall not have to speak ad lib immediately after your presentation I expect to be in SanFrancisco the day before the meeting and do you think it advisable to get together on this subject Sincerely Kenneth W. Smith M.D. Medical Director 4 UNIVERSITY OF CALIFORNIA BERKELEY BERKELEY DAVIS IRVINE LOS ANGELES RIVERSIDE SAN DIEGO SAN FRANCISCO SANTA BARBARA SANTA CRUZ SCHOOL OF PUBLIC HEALTH v a , . 1681 1681 A Tribute 10 the People of California EARL WARREN HALL BERKELEY CALIFORNIA 94720 January 26 1967 Kenneth W. Smith M.D. Medical Director Manville Corporation Twenty East Fortieth Street New York City New York 10016 Dear Ken that I have your two letters of January 16 and will it doesn't confuse those who do your filing make one reply hoping The Academy meeting will be held in the San Francisco Hilton Hotel on February 8 to 10. I am enclosing a program which covers the time and gives the location of the sessions I do not have a copy of my paper yet as I have not prepared the final version but I will see that you have one in advance of the meeting What I propose to do is to review briefly the present evidence of the major health effects of asbestos and to point out the many gaps in our knowledge and the hazards of extrapolation I will emphasize however my own feeling that it is not improper to speculate as to the significance of certain findings which we are in the process of studying I will get this to you in more specific terms for your critique The periodic health examination program to which you refer is that run by Dr. Morris Collen of the Permanente Medical Group I am enclosing a reprint describing the setup I talked to Dr. Collen this morning and understand that arrangements have been made for visitors on Thursday morning February 9 into will I am looking forward to seeing you and if you will call me when you town we can arrange to get together sometime on February 7 I hope be able to visit us in Berkeley get you Sincerely yours WCC js Enclosures 2 W. Clark Cooper M.D. Clinical Professor Occupational Medicine UNIVERSITY OF CALIFORNIA BERKELEY A\ BERKELEY DAVIS IRVIN~ LOS ANGELES RIVERSIDE SAN DIEGO SAN FRANCISCO { 7944A7944A SANTA BARBARA SANTA CRUZ SCHOOL OF PUBLIC HEALTH Maray15- Mary15- Maray15- os a ond Poo a ge io, wy or Maray15- A Tribute to the People of California BERKELEY CALIFORNIA 94720 February 2 1967 See eu ~ fe fr fo* Dr. Kenneth Smith , Medical Director Manville Corporation 22 East 40th Street New York N. Y. 10016 . Dear Ken I at the mately am enclosing a draft of the paper I will present next Wednesday American Academy of Occupational Medicine meeting It is approxias I plan to give it I will look forward chance then to talk over ments on the paper to seeing you on Tuesday the work we are doing and We should have a I can get your com- Best wishes Sincerely yours W. Clark Cooper M.D. Clinical Professor Occupational Medicine WCC Enclosure ; A Adres NEET NEET NEET . NEET NEET ~ ay ; ce eof fe fd a? Meer rr rl iw ron a 314 Ja Ja Ja a) 4 Altam Altam Altam Altam Altam 201 ; . Final Draft February 1 1967 7944B 7944B ASBESTOSIS FACT AND FANCY W. Clark Cooper M.D. PROLOGUE I will preface my remarks by making it plain that I will not be confined by the title on the program On the one hand I will not limit discussion to asbestosis as the term is commonly used but instead will range over all the health effects of asbestos And as for separating fact and fancy that implies more discrimination than I can bring to bear and as was sung in the Pirates of Penzance What is life without a little poetry in it INTRODUCTION The resurgence of interest in the asbestos minerals as environmental hazards to health during the past few years is something of which most of you are aware It reflects the tremendous increases in world production of asbestos and the impact of successive indications of association between asbestos and pulmonary fibrosis bronchogenic carcinoma diffuse mesotheliomata and other malignancies with the more recent demonstration of asbestos or asbestoid bodies in presumably exposed populations To refresh your memories I have slides showing the major types of asbestos and also two or three tables indicating trends in world production Prepared for presentation at San Francisco California the American Academy of February 8 1967 Occupational Medicine page 2 and the amounts that have been imported into the United States This is background material to indicate the magnitude of the problem It is only recently that there has been a real appreciation of the many variables involved in these relationships and the real complexity of the problem ASBESTOSIS The first facts to be discussed will be those relating to asbestos pneumoconiosis the disease that has come to be known as asbestosis No one disputes a effect relationship here but we are still woefully deficient in our knowledge of pathogenesis Are all forms of asbestos equally hazardous The evidence is against this Chrysotile disappears more readily from the lungs and in animals seems to be less fibrogenic The prominence of pleural calcification varies from area to area and type to type For example in Finland Raunio has recently reported a review of 600,000 chest films which show that in communes where anthophyllite mines are located up to 9.0 of films showed pleural calcifications whereas in other parts of East Finland not bordering on producing communes the prevalence was only 0.5 per thousand Nothing comparable to this has been reported in other asbestos mining areas A second question regarding asbestosis relates to its prevention by industrial hygiene Is it true that all that is needed is the application of currently recommended standards for dust control Most people who have looked into the basis for the present threshold limit value of 5 mppcf for page 3 asbestos which has stood in the books since 1964 realize that it rests on shakier evidence than most Midget impinger counts used in arriving at the figure include all dusts and the asbestos counted is mainly grains although rarely some fibers are included A large proportion of asbestos fibers have diameters below the resolving power of the light microscope and are not counted at all And it is now realized that diameter rather than length is the major determinant of falling speed Nevertheless most of us feel that the impinger count is a good indirect measure of dust control and that dust counts averaging 5 mppef should control asbestosis Evidence is beginning to develop that this is not true Wells 1965 reported briefly on his observations over 30 years in asbestos textiles His view was that multiplying average counts by years of exposure provided a good rough guida and that after 50 to 60 mppcf workers began to show evidence of asbestosis At the TLV this would be reached in 10 to 12 years Ferris last year examined insulating workers in a New England shipyard that had been surveyed by Philip Drinker 20 years earlier Conditions and counts now appeared comparable to those of 20 years ago and were averaged near 5 mppef Nevertheless a large proportion of workers had radiographic asbestosis which had begun to appear at 10 to 12 years Marr's counts in shipyards 1964 do not indicate weighted averages above 5 mppcf and our studies of insulating workars bear this out This strongly suggests that a weighted average of 5 mppcf is too high This is consistent with actual practices in the better asbestos industries Mitchell 1961 reporting on improved conditions in North Carolina textile mills cited counts ranging page 4 from 0.4 to 4.6 mppcf English industries under the Asbestos Industry Regulations have never operated with a numerical standard instead depending upon enclosure ventilation and masks to keep exposures as near zero as possible There are numerous other questions that one can ask relative to asbestos pneumoconiosis Have we been too complacent in assuming that the expectoration of large numbers of asbestos bodies is the expected response of an asbestos workers or is this in the employee really an indicator that we are tolerating too much exposure I don't think we know the answer There are also fundamental questions on pathogenesis on the nature of the pulmonary vascular impairment and the factors determining susceptibility MALIGNANCIES Asbestos would not be in the headlines these days if only asbestosis affecting a few hundred miners millers and insulating workers were the only problem It is the more recently demonstrated association between asbestos and malignancies that has created an entiraly new series of facts fantasies fallacies and fancies Lat us first look attthe evidence That there is an increased incidence of lung cancer in many groups of workers exposed to asbestos is a fact The cumulative evidence from epidemiologic studies that began with Merewether's analysis of causes of death in certified cases of asbestosis in the United Kingdom 1949 is now overwhelming Table 3. The evidence is not convincing as to the relative importance of different types of asbestos Chrysotile seems less certainly implicated and we are looking forward with interest to McDonnell's dating of the experience of Quebec chrysotile miners which several years ago when analyzed by Braun page 5 and Truan 1958 showed no excess risk It is of interest here that Jacob and Anspach 1965 who in Dresden a few years ago could demonstrate no increased risk on bringing their data up to date have shown twice the expected number of cases of lung cancer in men and ten times the expected number in women Their exposures were mixed however but they concluded that possibly partial control of asbestosis had permitted more workers to live to an age where malignancies occurred whicihn earlier days had masked malignancies In view of the spreads of dosage and response I find this an unlikely explanation We do not now have the answer as to whether the association is truly less for chrysotile than it is for crocidolite and amosite The next question and this will apply to other malignancies to be mentioned later is whether or not asbestos minerals per se are carcinogenic A promising area of direct research is aimed at determining the role of the asbestos fibers and fibrils as carriers of trace metals or of carcinogenic chemicals such as the polycyclic hydrocarbons to vulnerable sites The idea of a fibril that can migrate and then become a semipermanent implant is an intriguing ona This falls into the area of speculation or fancy if you wish to call it that but one that may prove productive Within the past 5 years there has been ample evidence of the association between asbestos and diffuse pleural and peritoneal tumors or mesotheliomata Since the first demonstration of a major series of cases that of Wagner Sleggs Marchand in 1960 there have been over 25 reports in the literature In many of them there have been suggested associations with asbestos either by Page 6 occupational history or demonstration of asbestos bodies in lung tissue sections Inasmuch as mesotheliomata were regarded as excessively rare tumors until recently the occurrence of even two or three in a series of asbestos workers becomes statistically significant Separating fact and fancy here becomes a bit more difficult First how accurate are our diagnoses of diffuse mesotheliomata There is no question but that rigid criteria to exclude primary tumors elsewhere are necessary inasmuch as the histologic characteristics of undifferentiated spreading tumors of the pleura and peritoneum are not always distinctive Close scrutiny of most series of diagnosed cases results in the exclusion of many of them Nevertheless where rigid criteria have been applied as in the cases studied by Hourihand in London Hospital the association with asbestos has been strengthened not weakened My impression is that it is holding up as additional studies are made A second question regarding these tumors is whether or not their incidence in the population as a whole is increasing Here again the impression one gats is that they are as reviews of cases over the past 10 years or so would indicate that the diagnosis was beginning to be made prior to wider publicity Third if there is an association is it more evident with one form of asbestos than another Here there is no question but that crocidolite and especially Cape blue crocidolite is the type where evidence is strongest In this country reported series have involved mixed exposures usually including amosite Claims have been made that because amosite was not used in the United States to any extent before 1935 and since mesothelioma characteristically have very long latent periods from first exposure to diagnosis that we are either page 7 seeing responses to chrysotila or are seeing only the first cases in an epidemic of effects from amosita That anthophyllite is not a problem in this respect is strongly suggested by a recent report by Raunio 1966 in which the very high prevalence of pleural calcification in anthophyllite mining areas of Finland was not associated with any increased frequency of cancer of the lung or of malignant pleural or peritoneal tumors We are left with a strong body of evidence that individuals with light moderate and heavy exposures to crocidolite or to mixtures of amosite and chrysotile show tumors of a type that is much less common in the general population The total frequency is quite low but as of now death certificate data are quite misleading due to incorrect diagnoses Studies in animals by Wagner in Cardiff and by Smith and others at Fairleigh Dickinson College have led to production of mesothelial tumors in hamstars in which various types of asbestos were introduced intrapleurally The difficulty in preventing cross contamination in laboratories has complicated some of these animal studies so that differences in response to different types of asbestos and factor remains unclear Nevertheless the carcinogenic potential of asbestos minerals is confirmed although the role of factors has not been settled FERRUGINOUS BODIES The final question is is it true that from a fourth to a half of the general population harbors asbestos fibers in its lungs The basis for such a statement is the fact that a number of studies of routine consecutive autopsy specimens in recent years have demonstrated asbestos bodies or as Gough page 8 would prefer to call them mineral or Gross ferruginous bodies As far back as 1928 Stewart had shown that smears of the cut surface of the fresh lung at autopsy would reveal large numbers of asbestos bodies in the asbestotic If any one tried this in a supposedly unexposed population before Thomson's studies in South Africa in the 60's it was not published Thomson et al 1963 showed 26.4 in 500 consecutive autopsies in Cape Town and later in 27.2 in 500 autopsies in Miami Other studies are shown in Table 4. The facts that have emerged from these are 1 Morphologically and in staining properties these meet all criteria for asbestos bodies 2 In no studies so far published have there been supporting data to indicate whether all most or some of the bodies were asbestos 3 In most series about 80 to 90 of the positive reports were on the basis of relatively few asbestos bodies per case 4 In those with many bodies there were often occupational or residential clues as to a source of asbestos and they were most commonly in males 5 In none of the series all small where correlations were attempted with diagnosis was there any apparent association with malignancies or other specific causes of death 6 There is ample evidence in the literature that called asbestos bodies can be found in workers with exposures other than asbestos e.g. graphite workers soft coal miners diatomaceous earth workers etc 7 Ferruginous bodies can be produced experimentally in guinea pigs with other dusts a.B. brucite aluminum silicate Presumably they represent a specific response to any relatively insoluble fibrous material in the lungs Speaking to this Cooke in 1927 said " . . there is no reason why any fine spicule of mineral should not have colloidal matter deposited around it and become molded into a page 9 curious body But as no other mineral dust is fibrous this occurrence = must be so rare as to be negligible from . a diagnostic point of view The question now is Cooke's statement of 40 years ago true today Or are we adding fibers of many kinds to our environment giving a confusing picture in our human samplers If as is probable many of the bodies that are being seen are really asbestos minerals there is need to determine their significance I think it unwarranted to draw the conclusion from what we now know that they presage an epidemic of neoplasms It is quite warranted to speculate on the matter however It is important not only to positively identify these ferruginous bodies but also to quantitate them in populations with known exposures to various fibrous minerals If those with small or moderate numbers of asbestos bodies show no detectable risk increased disease then we can feel more secure about those in whom the bodies are scant in number It is also important to learn the sources of these fibrous minerals that are found in lungs The view that asbestos minerals are indestructible is of course untrue is a relative term only and we cannot assume that the millions of tons used annually actually enter our physical environment forever Many are bound indefinitely into products that do not release them those that are released are subject to the effects of heat acids and other insults to minerals Nevertheless it is important to get a better idea of our asbestos balance so to speak page 10 SUMMARY In summary with the increasing use and indispensability of asbestos minerals there has come realization of some very real hazards that must be better defined and controlled Our present standards for dust control do not appear adequate to prevent asbestosis over a working lifetime and many segments of industry aggressively attacking the problem have already been using more rigorous standards The associations between asbestos minerals and malignancies of the lungs pleura and peritoneum become increasingly convincing Current efforts must be directed toward better definition of the importance of type size of fiber and the importance of factors It has been suggested that asbestos fibers act as carriers of carcinogenic metals or other substances to vulnerable sites The demonstration of ferruginous bodies in from quarter to half of the lungs examined in consecutive autopsies in a number of cities around the world points to an urgent need for the positive identification of the mineral fibers that are responsible If they prove to be asbestos we do not know what point on the dosage response curve is represented and consequently are not now in a position to estimate their significance in terms of human health EPILOGUE I have one final set of conclusions I think you will notice that I have not conformed to the usual pattern of talks with titles such as the one I was assigned lining up on the one hand a narrow list of the things page 11 we really know and then decrying the unwarranted and mischievous extrapolations that have been made Actually that could have been done here as I do think many misleading statements have really been made with respect to asbestos But I think that the more fundamental problem here is one that is a major affliction of occupational health We often try to emphasize that part of the challenge of our field is that it is at the forefront of medicine and technology where environmental hazards can first be detected in view of the relative levels of exposure and the opportunities to study populations at risk But when relationships are actually auspected and then gradually established very real and practical implications become immediately apparent So the speculations call them fancies if you will that are part of the normal process of developing new knowledge in other fields become menacing and are misused and misunderstood Polarization of views and severance of communication is the rule not the exception I think that this has been the case history of much occupational disease research in the United States and I can't say I know how it could be eliminated I do believe however that scientific progress requires both fact and fancy REFERENCES Raunio 1966 Wells 1965 Ferris 1966 Marr 1964 Mitchell 1961 Merewether 1949 Braun and Truan 1958 Jacob and Anspach 1965 Wagner et al 1963 page 12