Document O14Q3kYYeYyN4nJQk95RzoQmQ

FILE NAME Brakes BRK DATE 1975 July 23 DOC BRK127 DOCUMENT DESCRIPTION Memo - Meeting Minutes RE Dr. Selikoff Report - Manville M Manville 000091 000091 Internal Correspondence To Paul Kotin M. D. From George W. Wright M. D. Date July 23 1975 Copies file & C Subject MEETING ORGANIZED BY DR JOHN FINKLEA OF NIOSH TO CONSIDER A REPORT BY DR SELIKOFF AND HIS ASSOCIATES ON THEIR PRELIMINARY FINDINGS WITH RESPECT TO THE ENVIRONMENT AND THE HEALTH OF WORKERS EMPLOYED IN THE REPLACEMENT OF BRAKE LININGS and The The meeting was held in the afternoon of July 21 those attending are indicated on the attached exhibit , agendias also attached Dr. Selikoff opened the meeting by stating that their interest in the health of brake lining repair workers arose because of a report of several cases of mesothelioma occurring in auto repair workers There was some confusion in my mind at first as to whether this was solely from the New York area or a larger population It later developed that there were 4 and possibly 5 cases that had come to his attention from workers in this trade throughout the . United States He estimated that at least one million men might be thus employed and exposed to asbestos He re- peated several times that in his judgement it was not possible at this point in the development of information to say whether or not this represented an excess risk of mesothelioma but that he thought the observation merited fur- ther exploration He also indicated that he had reviewed this problem with appropriate people at the Ford Motor Company He then asked Dr. Langer to discuss the nature of the material found in the dust that accumulates in brake drums and which is by customary practice face and into the surrounding air at the blown off time that the surwork on the brake drums is being carried out Langer opened his comments by saying that others had reported timt 30 percent of the asbestos in brake lining is converted by high heat to Forsterite He indicated that mcdifiers present prevented the formation of Forsterite and no has found Forsterite ... brake drum dust only in one instance The only person I know of who says that the asbestos is converted to Forsterite is Paul Gross Others say that it fibrous is converted to an amorphous and essentially material Dr. Langer indicated that the residue was not pristine chrysotile fiber but he did not speak amorphous material Langer in addition said that he about 152 Pan Tin 1. D. July 23 1975 Page 2 found pure asbestos fibers This too has been reported by others in quantities of anything from 1 to 3 percent of the residual dust He then asked Dr. Rohl to discuss the fiber counts in the dust that was obtained It should be indicated that brake drum dust was obtained from cars repair shops and I Dr. Rohl indicated in taxi repair shops municipal bus believe some other similar workplaces that studies of the material blown from or obtained from the brake drum contained fibers in large numbers and these were chrysotile None of the fibers were more than 0.5 microns long and the bulk were under 0.3 microns In diameter they varied from 250 to 500 angstroms On the other hand he reported that the fiber count varied from 0.4 to 29.0 fibers per ml at the worker breathing air jet zone level where brakes It was my understanding were that being these cleaned by were fibers that were countable under the OSHA regulations and there- fore would be visible with the light microscope and longer than 5 microns It was not entirely clear to me whether these optically recognizable fibers actually came from the brake drum dust or not If they did I have a conflict in reconciling his electron microscope study with his light microscope studies Rohl also reported that in brushing the brake drums rather than blowing them off the fiber count OSHA criteria varied from 1 to 4 per ml during grinding the fiber count varied between 1 and 5. Most important was the finding that when men were bevellinthge brake linings by grinding the counts varied between 20 and 75 fibers per mi During punching riveting or sweeping the fiber count varied between 2 and 4 fibers per ml It is my under- standing that other kinds of grinding of the brake lining goes on in the fitting process Ed Fenner tells me that they do something called arcing and this involves direct grinding of the brake lining and is a very dusty job Rohl also showed data to indicate that there was a very rapid fall off in the level of count as one moved away from the source so that fiber counts 10 or 20 feet more away from the source of origin were lower than 1 fiber per ml and in general were in the neighborhood of 0.2 On some ing it developed that these shops were what would sidered to be very well run and therefore tend to question- be conhave lower dust count than would the average smaller shop In the pictures that were shown and the comments that were made there was no evidence to indicate that any sort of dust exhinust or suppression systems were prised that no direct referrence to in use I was extensive data sur- relative to brake drum dust by and by Manville Lynch by Jacko et as well as a small al by Anderson et study of the work al place during brake maintenance by lickish and Knight was not made by either Langer or Rohl Tea July July Page Hatin 23 23 1975 1975 3 At the request of the Unions Dr. Solikoff also did a preliminary examination loyed in the places where The men were not selected of 104 workers currently the dust counts had been on the basis of duration empmade or intensity of exposure some working only once a week where they would be exposed to brake lining operations but the majority of them had worked for between 10 and 20 years of the 104 29 had no direct exposure to asbestos or pul- monary disease but worked in the same area The data was presented so rapidly that I could not follow all of it but in part at least it is as follows Of the 64 men known to have direct shop exposure 16 had chest films that were read as category s or t small irregular densities with a protusion of 1/0 or more No controls for the read- ing were spoken of and I assume that these were read on one occasion by one person The inference was that these readings constituted disease attributable to the exposure There was no breakdown of how many had profusion readings in excess of 1/0 and thus I have no knowledge about the extent of the changes Later in the meeting I raised the question of the interpretation of this kind of information In the absence of controls there is no way to estimate the influence of bias in this kind of reading It is obvious that the roader knew the films came from an exposed group and the tendency under these circumstances is to find something in the way of an abnormality The best way to counteract this bias is to have a group of controls dispersed among the exposed group and have the entire set read blind In the absence of this there are two other ways of going at it neither of which were utilized in these readings The first of these is to have several readers look at the films independently The accepted reading is then the one that has the majority of the readers designation For example if the majority of the readers class a film as a 1/1 and a minority classify it as a 0/1 the ultimate reading used is 1/1 Some use reading by consensus but this is a poor and unacceptable method because usually there is one dominant reader who is able to persuade the others as to what he thinks it is The other way of going at it is to know what the exposure history is and be able to rank the observed population interms of intensity of exposure The films are then read with no knowledge of the intensity of the exposure and the distribution of readings has slightly loss bias than otherwise because the least exposure serves "/ a" control for the more heavily exposed This method is not as good as having multiple readers or actual control films interspersed amongst the films of the population under study With the information I have I don't know how to interpret their the inference that ray findings other than to say came from them was that all 16 of + that these Dark Dark . K a. July 201 July July July 201 201 \ ' J at can Page 4 individuals had disease The UICC classification is not a diagnostic classification in any sense of the word and serves only an epidemiological purpose I know of no basis on which one can conclude that people with a reading of 1/0 have actual disease Additional data was presented along the lines of pulmonary function measurements The data showed a substantial percentage of those who were directly exposed to have what was called restrictive disease I don't know what criteria were used for arriving at this designation and hence can't evaluate the finding If it was based on actually measured total lung volumes rather than just on vital capacity then the data has useful meaning The strong suggestion made by the Sinai group was that in these 104 individuals they had demonstrated the presence of asbestos related disease Maybe this was not their intention but in contrast to Dr. Selikoff's state- ment that 4 cases of mesothelioma did not constitute sufficient evidence to incriminate the exposure nothing was said to the effect that the ray and pulmonary function measurements may not have been very sound evidence of disease On the basis of these reports from Dr. Selikoff's laboratory several suggestions were forthcoming First of all there was an inference that Langer's studies had a implication that a public health hazard might exist At the very least the implication both from Langer and from Rohl was that the short fibers found in large numbers in the dust from the brake lining posed a potential threat to health of great magnitude In my comments I pointed out that there was growing experimental evidence that fibers of lengths under 10 micron did not produce disease in terms of pulmonary fibrosis and very likely did not produce mesothelioma On this basis I would think the presence of the very short fibers has little or no biological significance until proven otherwise The longer fibers are quite another matter since they are capable of producing asbestos associated biological effects In my comments I stated that the observation showing fiber concentrations of 20 to 70 fibers per milliliter in the bevelling operation did not surprise me In other settings the grinding of the surface of new brake lining is a known quite dusty process Depending upon the accumulated duration of exposure in this kind of operation one had every reason to expect that in those who have been doing this for a substantial length of time there would be a risk of pulmonary fibrosis and the other kinds of asbestos associated disease Even though this might occur only once or twice a week these high intermittent exposures might have an adverse effect Since no data in the way of cummulated dosage was presented there is no way in which the risk can be evaluated It was quite expecta study of clear that the Union representatives this category of workers to be made by Dr. Selikoff's Selikoff's made the blunt group Mr. Cofalo of the Machinists Union statement that if funds were not available he could promise that this meant from Union they could sources or become available Whether from the influence of the Unions on the Government was not clearly stated . As you know I had to leave before the metting ended and I don't know what the upshot of the matter was I asked myself the question what is to be gained by mounting a complete epidemiologic study based on observation of these workers and the environment of their workplace If the question is solely whether or not asbestos has the propensity to produce a biological reaction along the lines we already know I would say that making this study would be a very poor use of Dr. Selikoff's and his co- workers time and of expenditure of tax payers money We already have that kind of information and nothing in the presentation of the afternoon indicated that the exposure in this groupgroup was appreciably different from that which has been reported in other occupational groups If adequate information can be obtained then two questions might be approached by Dr. There is the implication fostered primarily Selikoff's group that short asbestos fibers 5 ... long produce all of the known biological effects in workers sub- stantially exposed They have taken this attitude on the basis primarily that short fibers are found in the lungs at autopsy and therefore must be the cause of the disease On the basis of animal experimentation others do not accept the hypothesis that fibers shorter than 5 to 10 microns in length have biological reluctance on the part capacity There appears of the Selikoff group to to be a accept the inferences of the experimental animal data The difficulty of of looking to human exposure for resolution of the question is obvious Those groups exposed ocupationally at least in studies up to the present are exposed to a mixture of iln ong and short fibers and there is thus no way of separating the affects of short versus those caused by long fiber Not even autopsy data will help in this respect since long fibers are subject to shortening by fracture with a passage of time If a group exposed only to the dust from the brake drums as described by Langer and Rohl could be separated out and looked at in terms of their mortality and morbidity experience then a study of the brake lining workers pop- ulation would be emminently worth while If this cannot be done and the exposures are mixed the population will be of no use for examining the effects of short fibers versus long fibers Another question might be looked at by study- ing this minds of group some as There still remains a to whether or not the question in > fiber per the cc level in the ambient air OSHA standard is adequate to protect the workers who are exposed throughout a lifetime If Dr. Selikoff's group can reconstruct the exposure histories of these workers in a manner that will give a ranking of July 23 Page 6 1973 the workers in terms of intensity and duration of exposure then a study of the relationship between this ranking and the biological effects would be useful If this cannot be done and if the population cannot be divided into those exposed solely to short fibers and those exposed to either solely long fibers or a combination of short and long fibers then I see nothing to be learned from an extensive study of this population that is not already known To be sure the employees in this trade might want an assessment of the potential hazards and this kind of information might be used in persuading both the employers and employees to create a safe work place I think this can be done by utilizing knowledge already existing with respect to biological effects and relating it to a thorough survey of the environment with respect to the level of asbestos fibers in the various kinds of jobs being done in this category of employment It seems to me that Dr. Selikoff's group constitutes a resource that should husband its time and facilities I would hope they would not embark on a study except in those areas where something useful could be obtained I think that a thorough investigation into the environment could be thought of as useful study on the basis of what is now known In fact under the regulations set forth by OSHA the employers should already have developed that information The regulations require that when employees handle materials in processes through which they might be exposed to the inhalation of asbestos fibers certain envir- onumental and physical examination requirements must be satisfied I would think this would be the most useful avenue to pursue since the requirements under OSHA are quite clear cut I don't know at this time what can be antici- pated in the way of reconstructing exposure histories or in dividing the population into the two groups with the respect to length of fiber On the basis of past experience I would not be very hopeful that this could be accomplished with a degree of accuracy permitting any conclusions from a biological survey to be drawn Several other points arose from this meeting that seemed to me to be important First of all insofar as I can learn labeling of brake lining materials in a way that would inform the user and the worker of the inherent hazard related to the various .ys in which the material might be handled has not been a common practice if done at all Mr. Sam I would hope Meyers of the this would be corrected at .. once United Auto Workers Local 259 showed posters his group have developed warning of the possible effects of brake lining handling on health constructive remarks during the meeting It He also made seems clear that some mechanism must be found for alerting all workers in this trade to the potential hazards and the need to join Paul Kotin N. D. July 23 1075 Page 7 with the employers in finding ways to work safely An educational program through the Unions as well as the employers should be mounted as quickly as possible Since this trado may involve only a few people in a given place and presumably is not totally uinionizedI believe this may be a matter of considerable magnitude The discussions of this particular afternoon demonstrate as well as anything I know the obligation on the part of manufacturers to know where their products containing potentially toxic material go and the way in which they are used In those circumstances where a hazard can be created by the use of the product a means of informing the worker must be found At the very least this should be labelling and in all probability it should be a joint educational effort on the part of the workers organizations and the employers and the producers Unfortunately labelling is often times either ignored or loses its impact with the passage of time For this reason more persisteanntd active methods should be found for accomplishing the purpose In view of the nature of the problem and the fact that the current OSHA regu- lations should have broughitt to the fore I was surprised that no representative of OSHA was present Representatives| of EPA were present even though their concern would be expected to be less at this point than should be true for OSHA I regret that I was unable to attend beyond 3:40 I will call Dr. Finklea and give me more information and if so I will to you the meeting see if he can transmit this George W. Wright M. D. bek