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FILE NAME Manville JMA DATE 1973 May 21 DOC JMA007 DOCUMENT DESCRIPTION Presentation on Asbestos by Dr. Irving J. Selikoff at American Industrial Hygiene Conference with BC Notes 7/5/98 American Industrial Hygiene Conference Selikoff Questions U.K. TLV Selikoff's 5/21/73 talk at AIHA Conference contrasts H. Lewinsohn's higher diagnosis of asbestos is at T & N's Rochdale plant 40-50 with the much lower prevalence reported by Dr. Knox 7-8 in developing the British asbestos standard only a few years earlier Selikoff calls for review of the OSHA asbestos standard which was largely referencetdo reports from the  000110 Presentation on Asbestos by Dr. at Irving J. Selikoff American Industrial May 21 1973 Hygiene Conference This year 1973 marks 50 years since the examination of the first case of death due to asbestosis Dr. Cooke in Leeds described this fatal disease in 1924. He might well have been asked the question which points a dilemma in which we still are If he had been asked what exposure of this asbestos textile worker resulted in her fatal pulmonary fibrosis he would have had to say I don't know Because 20 years ago when she began work in this textile factory no dust counts were done Now the dilemma that he faced is still very much with us at this time because the disease that we are now seeing is the result of exposures at a time when we were not alerted and environmental measurements were not made We find this a great difficulty in our own work and perhaps it may be well demonstrated by the first slide which I will read to you in view of the circumstances This is a slide of the ray results in 1,000 employee workers in the New York area examined by us and it demonstrates that out of 725 people with less than 20 years from onset of exposure most had normal rays When they were abnormal they tended to be minimally so On the other hand more than 20 years from onset of exposure of the over 300 men so examined few had normal rays and when they were abnormal not infrequently the fibrosis was extensive So the 20 year rule which was found in 1924 is present with us today The description of lung cancer 1935 and subsequently of pleural mesothelioma in 1954 and after- wards in 1955 of peritoneal mesothelioma and subsequently of other tumors has done nothing to resolve this question because they too have had this difficulty which we still face found it so in our studies We have For example in the New York area we have been following 632 members of the Asbestos Workers Union these are the insulation workers who were on the union rolls on January 1 1943. You will see in this slide that for the first 10 years from 1943 to 1947 and 1948 to 1952 the total number of deaths was almost exactly what was expected It was not until after this 10 year period had passed that we began to see the extraordinary mortality patterns that are still with us We found for example that after 20 years whereas there should have been 6 or 7 deaths of cancer in the lungs and pleura mesothelioma there were 45. There should have been 9 or 10 deaths of cancer of the stomach colon and rectum There were three times as many 29 and of course there were 12 deaths of asbestosis where none had been expected Yet as we go longer with this group - we have followed them now through December 31 1971 and these are unpublished data I thought you'd find them interesting - we have found that of the survivors of this 1943 group there should have been another 85 deaths 168 have occurred There should have been 4 or 5 deaths of lung cancer There were 42. There should have been no deaths of mesothelioma which almost never occurs in the general population There were 25. There was the small increase 3 or 4 times increase in intestinal cancer and the asbestosis deaths so that the longer we go from onset of exposure the more evident the risk appears We have in order to further study this question undertaken a second study and these are the first reports of this second study not yet published On January 1 1967 we registered every single union insulation worker in the United States There were 17,800 members of this union on that date and Dr. Hammond and I have followed them from January 1 1967 through December 31 1971. These are the results found in that study Whereas there should have been 805 deaths among them given their ages there actually were almost 1,100 And once again the lung cancer death rate was extraordinarily increased Whereas there should have been 44 expected 213 bronchogenic carcinomas actually occurred There should have been no deaths of mesothelioma there were 77. There should have been a small number of gastro- intestinal deaths there were 3 times as many as expected And of course there should have been no deaths of asbestosis which doesn't occur in the general population and there were 78 When we analyze these deaths by duration from onset of work among these 17,800 men we found that in the group less than 15 years from onset of exposure there was no significant increase in either lung cancer or mesothelioma We did not see one mesothelioma in less than 15 years from onset of work although we were observing almost 10,000 men in this category On the other hand once the 15 years passed we found that the ratio of expected to observed deaths was 5 6 and 7 times and now the mesothelioma deaths began to be seen We have also looked to see whether this were so in an asbestos products factory making insulation making many other products and to study this we made a list of every single production worker in this plant on January 1 1959 who had on that date worked at least 20 years We have followed this group 689 people through December 31 1971. And once again we have found that whereas there should have been 8 or 9 deaths of respiratory cancer there were 35 of which 27 were lung cancers 8 were pleural mesotheliomas 7 were peritoneal mesotheliomas the same increase modest increase in intestinal cancer and asbestosis Finally to try to get some sense out of the duration from onset versus the actual exposure because most of the men in the three cohorts that I have just reported to you had worked continuously in one group we were able to find a very significant difference in the amounts of work This was a factory which opened in June 1941 to make insulation for the U.S. Navy Nine hundred thirty men were employed for the first time from '41 to '45 The factory closed in 1954. Some 11 men worked for only 1 day They didn't like it Some worked until the plant closed in '54 Following this group of 933 people it was a darn good plant - they got their Navy E we have found that in these 933 men there should have been 300 deaths by the end of '71 there actually were 484. And once again - it's almost monotonous - the same 7 times increase in lung cancer pleural mesothelioma peritoneal mesothelioma intestinal cancer and asbestosis But of these men approximately third worked for less than 3 months third worked from 3 to 11 months third worked for more than a year and we have found that although the group with more than a year of exposure had a very significantly greater ratio of expected to observed deaths 11 times as many lung cancers as expected still even less than 3 months of work was enough to give a 3 or 4 times increase in bronchogenic carcinoma provided they lived long enough and provided you looked at them 30 years later Now all of these data indicate that what we are seeing now, the current mortality experience is the result of the inadequately controlled exposures of the past However the problem is with this long latent period how do you find out what the exposures of the past were to relate them to the epidemio- logical evidence of disease at the present time Unfortunately in the United States we are at a loss for this There are no sets of dust counts and resulting disease observations from the first case reported in the United States in 1930 to permit judgment here of acceptable levels There are two approaches Both have been used First of all if there were measured dust levels 20 years ago and if we could identify the populations who were exposed to those levels 20 years ago we could make some correlations One of course would be asbestosis The other approach has been to take dust measurements now and get some sense of how these measurements now related to what existed in practice 20 30 and 40 years ago This has been done but there are significant differences with this technique First of all in the past very few dust counts were done The current techniques membrane filter methods phase microscopy etc. were not used at that time For example the Dreesen study Also at that time all particles were counted rather than only fibers and as we try to convert particles per cubic foot to fibers per cc the results are unfortunately uncertain We have on the other hand had some measurements of what exists today in the construction industry with the use of insulation material and we have found that using fibers per cc that in general somewhere around 5 to 10 fibers per cc exists in these environments Now we don't really know whether this was true 20 years ago There are 4 studies that provide evidence First there is the original study of Dr. Fleischer and his colleagues in the U.S. Navy shipyards published in '46 and done in '44 '45 A different instrument was used and a time weighted average of 25 fibers per cc could be obtained but other glass fibers and so forth were included Murphy and Ferris and their colleagues have looked at shipyard data published in '68 and '71 They came to somewhere around 10 fibers per cc Balzer and Cooper in San Francisco insulation workers have come to around 6 fibers per cc And in our laboratory looking at construction work in shipyards throughout the United States we have found exactly what Balzer and Cooper have found somewhere around 6 fibers per cc But this is reconstruction And we don't really know that this existed 20 years ago While this is the dilemma which we faced we thought that 6 fibers per cc somewhere around that 10 fibers per cc existed in the past but we weren't sure We know what the disease is I've just shown it to you Therefore we were all very much impressed and greatful when the British Occupational Hygiene Society gave us the answer In 1968 the British Occupational Hygiene Society published a report stating that 4 fibers per cc or 2 fibers per cc would likely be safe The basis for their report was the report of their sub- committee on asbestos published in the Annals of Occupational Hygiene In 1968 and it read The results of recent work the study of John F. Knox and Stephen Holmes have been made available to the Committee by the asbestos industry and it is on these recent results that the new standard is primarily based What they came to that it would be safe to have 100 fiber years such as 2 fibers per cc for 50 years or 4 fibers per cc for 25 years The work of Dr. Knox and Dr. Holmes they were both members of this committee were valid Dr. Knox was Chief Medical Officer of Turner Brothers Asbestos Company in Rochdale and Dr. Holmes was their Industrial Hygiene Scientist The bases for these data were then published by the British Occupational Hygiene Society Dr. Knox had rayed all production workers at Turner Brothers Asbestos Company in Rochdale as of June 30 1966. There were 931 workers in this plant of whom a large number had been more than 10 years in their employ They had done dust counts very good dust counts from 1951 on and therefore we had a population for the first time where dust counts could be related to clinical evidence of disease In the departments where the dust counts were 10 to 15 fibers per cc of the large number of workers there employed 7 showed some ray abnormality which could have been asbestosis On the other hand of 70 or 80 people working at 3 to 4 fibers per cc only one was reported to have an abnormal ray This being so the subcommittee which itself did not review the data but which reviewed the numbers submitted to it the subcommittee reviewed the data given it and decided that since only one worker exposed for 20 years or more at 4 fibers per cc showed evidence of asbestosis half that level 2 fibers per cc would be prudent and safe And if I were on that committee I would have come to exactly the same conclusion When these data and this conclusion and this recommendation reached the United States it did as I say impress all of us So much so that on February 28 1969 Howard Ayer sent the following letter containing this statement to 28 asbestos companies and 50 state health departments - Quote From these standards that is the British Occupational Hygiene Society recommended standard one would gather that concentration below 2 fibers per cc are probably safe -- fair statement Indeed when the criteria document was submitted by NIOSH last year 1972 it stated The development of a standard for asbestos dust in Great Britain and the evaluation made by the British Occupational Hygiene Society Subcommittee on Hygiene Standards for Asbestos which considered data to reduce the risk of asbestosis was given great weight in the development of this asbestos standard That is the origin of the 2 fiber per cc standard Two fibers per cc obviously is 2 million fibers per cubic meter A working man inhales somewhere around 8 to 10 cubic meters of air in an eight working day which means that we have told him that he can safely inhale with an uncertain unmeasured retention safety inhale somewhere around 20 million fibers in an eight day longer than 5 microns -10- As Mr. Dement has just told us anywhere from 20 to 99 of fibers are smaller than 5 microns and therefore the total number of fibers of all sizes is somewhere around 20 to 40 billion Now some new data has recently appeared which I thought might be of interest to you In 1968 Dr. Knox retired as Chief Medical Officer of Turner Brothers and was replaced by a young South African Dr. Hilton Lewinsohn Dr. Lewinsohn has rayed all of the workers at Rochdale in December 1970. The populations however were not entirely men in the scheduled areas identical - that is Dr. Knox had examined only the production areas 913 - whereas Dr. Lewinsohn included all employees including the office personnel and had therefore a larger number To some extent you could say that this diluted the population but I think it was a wise thing to do Also some of the people working there in 1966 were no longer employed obviously they had retired or died and some new workers had been added The very large majority of course were in both surveys Dr. Lewinsohn reported the results of his December 1970 ray of the Rochdale personnel in the Royal Society of Health Journal in 1972. Dr. Lewinsohn's data are on this slide It demonstrates that of those with let's say 20 to 29 years from onset of exposure of 114 rayed 51 had abnormal rays All together total abnormalities were 55 of all people who had reached 20 to 29 years from onset and of these actual pulmonary fibrosis was seen in 21 out of 114. Of those who had reached 30 to 39 years from onset 78 had abnormal rays and 17 out of the 42 had actual pulmonary fibrosis Of those 40 to 49 years there were too small a number to show When we put these two sets of data together we can find that as of let's say 400 fiber years Dr. Knox had found in reading the films that somewhere around 7 or 8 % had abnormal rays whereas in the same population a different film reader had found that somewhere between 40 and 50 had abnormal rays There is obviously a considerable discrepancy in the two sets of film readings Now when these discrepancies were discussed with our British Colleagues last Fall in Lyon France in October Dr. Holmes made the following statement Thus the information although the best available at the time was to say the least scanty for the purpose And some of us who were associated with it have become increasingly concerned with the authority with which it has become invested in the international field meaning the United States The time has therefore probably arrived for an date reappraisal of the original data I have communicated with Dr. Lewinsohn in the last three weeks and am informed that there are definite plans to undertake this review in the future It has not yet been done In conclusion then as a result of these new data from Turner Brothers Asbestos Company we can say that if the 1972 report of -12- the Chief Medical Officer of Turner Brothers Asbestos Company correctly represents the disease incidence associated with prior levels of asbestos exposure in the company then the asbestos standard of the Department of Labor places U.S. asbestos workers at serious risk of irreversible often fatal disease and in my opinion it should immediately be reconsidered In conclusion then unfortunately I feel we are in the same dilemma still after 50 years that Dr. Cooke found himself in in 1923 Thank you very much QUESTION FOLLOWING DR AND ANSWER SELIKOFF'S SESSION PRESENTATION In the asbestos products factory in which men employed for only three months were found to have a significant increase in lung cancer were smoking histories obtained Dr. Selikoff The answer is Yes and those data are now being analyzed but I would be amazed if we found any lung cancers or any more than a trivial number among those who did not smoke cigarettes We have failed to see any significant increase in the incidence of lung cancer among asbestos workers who do not smoke cigarettes We have been following 2,066 non- smoking insulation workers from January 1967 and we have only seen two lung cancers among through 1971 them On the other hand of 9,590 cigarette we have found 145 lung cancers smoking whereas insulation workers only some 30 were expected Bronchogenic carcinoma is almost limited to ciga- rette smoking asbestos workers This is not true of peritoneal mesothelioma it is not true of asbestosis and it is probably although our data is too scant yet to be sure it is probably not true of pleural mesothelioma But of lung cancer - there is no question - this will not occur by and large among asbestos workers who do not smoke cigarettes I would like to ask Dr. Selikoff if he thinks the new standard should include both a total dust count - if there is a new standard At least standard - both in our set on a total dust count and a per cent fiber count experience we seem one rather than the to vary independently A other could be quite mis- leading Ray Murphy me to give has asked me a very embarrassing an opinion where I can't give it question He even on fiber asked counts He now asked me whether I would do it on total counts rather than just fibers The answer is I don't know But I'm not very impressed if I can upstage Duncan Hol a bit who is going to review this impressed with asbestos tomorrow morning - we're standards which rely upon not very dust counts being done May I give you some data Very depressing data if you think these are depressing On June 7 1972 the asbestos standard came into effect And it said that every company using asbestos had to do at least one dust count one dust count in the next six months That is by December 6. We on December 7 did a survey of insulation workers in the United States and we now have some 5,000 odd replies Each man was asked about the dust counts that he personally had seen in the six months when every company was supposed to United States insulation industry do a dust count fewer than % of In the the in- sulation workers saw even one dust count done from June 7 to December 6 1972. Obviously then dependence upon dust counting as a means of control in this unusual industry has many deficiencies It is really one question in two parts perhaps The fibers at the Turner Asbestos Company Holmes study what were these and could you comment would you comment on the possible differences that you think may be between crocidolite and chrysotile and amosite The fibers in Turner Brothers since it was a textile operation were largely chrysotile We can give you no information con- cerning had any crocidolite crocidolite because none of exposure They the had workers studied by us chrysotile exposure and many of them had amosite exposure Indeed in the plants in the factory making the Navy insulation this was almost entirely amosite So our data apply only to amosite and to chrysotile and unfortunately I can give you no information on the relative hazard of crocidolite I would suggest however that if crocidolite is more dangerous than amosite or chrysotile it is going to be almost as bad as chloromethylether Laughter Dr. Selikoff are you aware of a particular type of asbestos fiber mined in Ontario called Headman Fibers which have been found to be relatively inert by Paul Gross and others I presume that you mean the fibers mined in Quebec not Ontario No mined in Headman Mine in Ontario No I do not know these particular fibers and I would be delighted to know of an asbestos fiber which is comparatively inert They claim work - and chrysotile - and Paul Gross and others have done experimental they have found that this particular fiber which is has been in experimental work found to be inert Well I would be delighted to see those in industrial to see use those indeed I'd be delighted Thank you Dr. Selikoff PREVALENCE OF RAY EVIDENCE OF ASBESTOSIS IN ASBESTOS TEXTILE WORKERS 60 | | | 50 AFECTD 40 bo YEARS YEARS YEARS YEARS INDVUALS 20-2920-29 30 7 20-29 20-29 QO OF YEARS YEARS YEARS 20 rere YEARS PERCNTAGE 10-19 10-19 YEARS 10-19 YEARS YEARS 10 YEARS 0-9 0-9 LEWINSOHN o YEARS YEARS YEARS YEARS 30-39 30-39 30-39 30-39 a onl we G 0 0 100 200 CUMULATIVE EXPOSURE 300 YEARS 400 500 X FIBERS 600