Document NGv7Eqmr89rM4k5QxG6XMqY3V

FILE NAME Brakes BRK DATE 1975 July 23 DOC BRK202 DOCUMENT DESCRIPTION Internal Memo RE NIOSH Meeting about Dr. Selikoff Report Summary o Tew hy4 y R* AV Manville 000091 0091 Internal Correspondence To Paul Kotin M. D. From George W. Wright M. D. Capies file & C Date July 23 1975 Subject MEETING ORGANIZED BY DR JOHN FINKLEA OF NIOSII TO CONSIDER A REPORT DY DR SELIKOFF AND HIS ASSOCIATES ON THEIR PRE- LIMINARY 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 agenda is also attached Dr. Solikoff 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 Tt 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 poss- ible at this point in the development of information to say whether or not this represented an excess risk of meso- thelioma 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 I then asked Dr. Langer to discuss the nature of the material founidn the dust that accumulates drums and which is by customary practice face and into the surrounding air at the the brake drums is being carried out blown off time that in brake the surwork on 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 Forsterito le indicated that HedifiersHedifiers Hedifiers present prevented the formation of Forsterite and he has found Forsterite in 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 is converted fibrous material chrysotile was not pristine to an amorphous and essentially Dr. Langer indicated that the residue fiber but he did mot speak about amorphous material Lager in addition that he tail Kotin M. 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 in taxi repair shops municipal bus repair shops and I Dr. Rohl indicated believe some that studies other similar workplaces 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 0.3 microns In diameter they varied from 250 to under 500 angstroms On the other hand he reported that the liber count variod from 0.4 to 29.0 fibers per ml at the worker breathing zone level where brakes were being cleaned by air jet It was my understanding that these were fibers that were countable under the OSILA regulations and theret-here- 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 the 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 bevelling brake linings by grinding the counts varied between 20 and 75 fibers por ml 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 coes 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 noved 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 question- ing it developed that these shops were what would be con- sidered to be very well run and therefore tend to have lower duse 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 exlinust or suppression systems were in any sort of use I was dust sur- prised that no direct referrence to extensive data relative to brake drum dust by Lynch by Jacko ot al by Anderson et al and by Manville as well as a small study of the work place during brake maintenance by Mickish and Knight was not made by either Langer or Rohl