Document ZrZbMq3db2y7pDORjmgonpe8

* CCBt r I March 11, 1976 Mr. E. H. Feierabend Vice President PPG - winchester Subject* Notes on Qivlroroaenta1 Asbestos Meeting with N York Transit Authority, Hew York Air Resources, and Representatives from Environnenta1 sciences laboratory at Mt. Sinai Hospital On Thursday, 2/26/76. I had occasion to attend a meeting with representatives aC the above organisations to review plans fox subway air sampling or asbestos. Although a portion of the meeting was devoted to consents and questions related to air sampling procedures and the need for actual physical testing of the RPG brake shoe, there were some formal and informal comments made which ore of direct interest to the Friction Products Group. The Environmental Sciences Laboratory at Mt. Sinai Hospital headed by Dr. Selikoff has for a number of years been accumu lating data on asbestos levels in the environment, first as related to occupational exposures and more recently as they relate to total environmental exposure. Their most well known recent study was the determination of exposures during brake shoe relining activities in repair shops. However, the occupational limit of 5 fibers per cubic centimeter greater than 5 microns in size was used as the index of exposure. Submicron asbestos concentrations were not publicized. This is now being followed by an urban street level study contain ing submicron fiber data which will be published in Environ mental Technology next month. xn a aide conversation with Mt. Sinai representatives, the reason for their strong interact in submicron brake shoe emissions became apparent. With the integration of some final data into their research, they feel that they will be able to demonstrate conclusively the carcinogenic responae of the body to asbestos fibers, particularly those in the submiezon and Angstrom (10-? millimeters) ranges. The research developed because of the fact that asbestos fibers, being relatively indestructible, will fracture and separate into uncountable numbers of minute fibrils in the environment, continuously multipyling due to the increasing contribution from man-made sources. The fibers have minimal terminal velocity because SPNY 006289 . * SCF-ABEX-1895 Hr. B. B. Peierabend -2- March 11, 1976 of their size and aerodynamic characteristics# and remain suspended indefinitely. The Mt. Sinai representatives stated that tbuy have regularly been finding street level concentra tions of from i to 100 fibers per cubic centimeter. As a comparison, tho tentative ambient Mr quality criteria proposed by the SPA is .04 fibers per cubic centimeter. They were emphatic in their assertions that braking systems which thsy have investigated to date do not readily convert all the asbestos through dehydroxyletion to forsterite. They claim that micron and submicron particles are readily detectable bots* un^er laboratory and street conditions. This would suggest braking surfsee temperatures of around 500C ox below. This is counter to previous research which has revealed light braking temperatures of 800-900 c and heavy braking temperatures of 17^0--1890C. Although I have not yet been able to confirm their assertion# it appears that the Federal Government has extended a large grant to Mt. Sinai with which to complete their dausati#c study of cancer induction by asbestos, with the grant, Mt, Sinai has recruited researchers from a wide variety of dis ciplines to concentrate their efforts to this end. This not only includss medical research teams, but environmentalists as well tc document the pervasiveness of the problem. - They are also very aware of the problems associated with the use of baghousos for asbestos collection purposes. The state ment was made that they have observed high levels of submicron particles in the vicinity of asbestos manufacturing plants utilizing these systems. The explanation la as follows. When considering baghouse efficiency on a weight basis, it is relatively easy to get high efficiency with particles whose size is in excess of 5 microns. However, efficiency falls off with a decrease in particle size, and apparent high effi ciencies are much less meaningful in terms of nurbers of fibers. It can be assumed that 103 average fibers of asbestos weigh approximately 1 nanogram. If 1 gram cf asbestos material approaches a baghouse filter rated even as high as 99.999J6 efficiency, then the quantity passing through will be 9.90001 grams or 10^ nanograms. And since 1 nanogram Is approximately equal te 103 fibers, then a total of 107 (10 million) fibers will pass through the filter for every 1 gram SPNY 006290 Mr. E. B. Feierabend 3 March 11, 1976 of material impinging upon it. Thus quoting in terms of mass efficiency has no real meaning. It bears no obvious relation to the hunflaers of fibers being emitted. The view held by the Federal occupational health authorities to date has been that the medical evidence as to the size of fiber responsible for adv.-se health effects is not positive nor is the question of whether fibrils or fibers are most hazardous, and that it would be premature to impose inflexible or overly rigid regulations, if and when the Mt. Sinai research establishes the causation of cancer induction by asbestos, this view will change, particularly since the incidence of lung cancer in the general" population has sharply increased ' over the past several years. The ramifications are readily apparent. As long as the problem has remained one of limited occupational and ancillary exposure, the stress has been . placed on containment and protection of exposed employees. ' If the problem becomes one of national or worldwide proportions, affecting the population at large, demands for a ban on the use of asbestos can be anticipated. This would apply parti cularly to the brake shoe industry which would be hrrd pressed to find a suitable material replacement within an acceptable time limit. There is little likelihood that complete collec tion of brake shoe emissions at the point of release would be practical or acceptable, although this possibility was raised during the meeting. One final point should be made. The present 5 fiber/M^ occu pational exposure limit (2 fibers/fa-* as 0f July, 1976) was established as an index to contain exposure not only to fibers above 5 microns in size, but those below that size as well. An unexpected and controversial proposal to reduce the limit to 0.5 fibers per cubic centimeter was recently published by OSHA. Although conjecture at this point, it is possible that this proposed legislation was not based on inadequately docu mented and poorly defined British studies set forth in the document, but was based on prior knowledge of the potential disposition of present research MDGiEJ CC: i G. L. Routine 1&. Niaholson >/C. C. Blackwell, Jr. , M.D. M. Davia Gidley, Manager Industrial Hygiene and Environmental Control r' SPNY 006291