Document mmr1MMekVd3a8GKNe499bQNb

TJSSIAI-S STANDARDS BZRGEN MALi. O"P"ICE CENTER E 210 ROUTE ^ PARAMUS N J 07652 IXSTITUTS, H'C. PLAINTIFFS ! EXHIBIT FMSI-130 January 8, "976 Dr. irvi'i J. Selikoff Envi ronrar.tal Sc i ence Laboratory IOC Street and Fifth Avenue New York. Lew York "CD29 A.tin: Mrs. Kaffenburch wen v i emer.; Per our ohone conversation of this cate, i am forwarding: 1 Photocopy, from Automotive News '975 Almanac issue (Copyrighted) of table: "l'. S. Motor Vehicle Manufacture , Wholesale Value, and Use, 1904-1974V. coov, SAD raoer 730548, ''Brake and Clutch Emissions Generated During Vehicle Operation,R dv dacko, DuCharme and Somers. The tabulation appeared in the A-jtomot j ve News 1975 Almanac Issue; Automotive hews 965 East Jefferson Avenue Detroit, Micnigan 4S2C7 ihe source o: the cata was: Motor Vehicle Manufacturers Association 32D New Center Building Detroit, Michigan 4S2C2 in my conversation with Mrs. Kaffenburgh, I requested copies of, or reference to, technical oaoers with data on asbestos fiber counts observed in shoos doing work on brakes and/or clutch facings (8 hr T'.VA counts, or ceiling concentrat ions,. Sincerely, FfilCTIC. MAT Eh! ALS S7A.LDA.hDS !7u7c sure: E. V.'. Dr i si ane Executive Director Asbestos exposure during brake-lining maintenance and repair Problem: Brake-linings may contain as much as 50% chrysotile asbestos, and the disintegration of the lining during braking releases fibers, some of which become constituents of brake drum dust# Other fibers are released into the general environment. An investigation was made to obtain in formation concerning asbestos exposure of automobile and truck maintenance workmen, particularly those responsible for brake-lining work. Personal air sampling was carried out at various auto repair shops, taxi fleet repair shops and several municipal truck repair shops. It is es timated that there are about 124,000 men in this work in New York City, alone, The exposure of workers during brake-lining maintainance and repair is of interest as a background to investigation of their health experience. This, in turn, has considerable significance in determining whether brake lining dust is pathogenic. If it is not, we would have little concern regarding brake-lining dust as a source of general environmental exposure to asbestos. On the other hand, if workers exposed to this dust are found to have asbestos disease, then the effects of exposure of the general pop ulation to the same dust, albeit at much lower levels, would have to be further evaluated. Materials and methods: Personal air samples were taken during brake-lining maintenance work. Air samples were also taken at adjacent sites, including customer waiting areas and automobile showrooms. The standard techniques for filter pro cessing and fiber counting which have been adopted by the Occupational Safety and Health Administration of the Department of Labor. Both optical and electron microscopic methods were employed, the latter because the great majority of asbestos fibers were too fine to be detected by optical microscopy. X-ray powder diffraction and microchemical scanning electron microscopic analyses were also utilized to identify chryBOtile asbestos in brake arum samples. Results to cate; Table 1 snows the levels of asbestos found during tbe roost common operation of brake-lining maintenance. When a brake lining is brought into a repair shop for inspection or replacement, the wheel is removed and all loose dust is removed from the drums and back plates by means of a compressed air jet. The cloud that is produced is visible, and re mains so for minutes afterward. There is minimal, if any, effort to con trol dust in most garages and workmen very rarely wear respirators. Table 1 shows that fiber counts are high in the operator's area, and that there are moderately high concentrations at least 20 feet away. Background sampling during the same operation shows that immediately after jet air blowing and for at least 14 minutes afterward, there are measurable con centrations. These measurements were taken at varying distances from the operator (from 10 to 75 feet) and show that other people within that per imeter are exposed, including mechanics, shop management, salesmen and customers. Ten samples of brake drum dust were processed for electron micropsopic examination without changing the size distribution, and asbestos fibers present in the dust were measured. The results are shown in Table II. It was found that most fibers are too small to be seen by optical microscopy; almost all of them were shorter than 0.4fi in length. of respirable size. Virtually all were Prior to this study, it had been generally accepted, on the basis of lim ited data, that asbestos brake-linings are thermally altered to an inert, presumably harmless dust, during braking action. Our observations show that asbestos fibers do survive. This has been found in every brake drum dust sample analyzed by x-ray diffraction, electron microscopy and microchemical scanning electron microscopy. Table 111 and IV present data collected during brake lining maintenance operations at the hew York City Department of Sanitation truck repair shop. Two important operations are performed in this large shop for reasons of economy-grinding and bevelling of linings, otherwise generally performed during manufacture, Accordingly, these studies relate to levels of as bestos exposure experienced by workers engaged in manufacturing. New linings are ground to remove imperfections on tbe surface and used lin ings are salvaged by grinding the surface to remove grease and dirt fiber concentrations experienced during grinding ranged from approximately 2,0 6 3 to 7.0 large (optically visible) fibers/ml of air (2x10 - 7x10 /m ). The background or area samples for this operation ranged from 1,2 to 0.2 63 fibers/ml (1.2 - 0.2 x 10 / ) with a general decrease with increasing distance away from the operator. From six to ten other mechanics would thus be exposed to perhaps about one fiber/ml. A concentration of even one fiber/ml is equivalent to inhaling 6 million large fibers per working day, those longer than 5|_i. Much larger numbers of shorter fibers would simultaneously be inhaled. Table IV shows fiber concentrations measured during bevelling of new truck brake-linings. The lining edge is bevelled on a grinding wheel, so that the brake will grip properly. Concentrations were very high, ranging from 32 to 72 fibers/ml, and background counts were measurable up to 30 feet away. Significance: The data indicate that, during brake-lining maintenance and repair, work men in garages, service stations and brake repair shops are exposed to asbestos and thus may be subject to serious cancer risk. Others, at some distance from the repair work, are perhaps subject to the same hatard. These environmental measurements will be of value in considering the health experience of brake-lining repair workers, as a background to evaluation of tbe importance of asbestos from brake-linings as a factor in general community asbestos air pollution. Publications: To be published. Investigators: A. M. Langer, Ph.D., A. Rohl, Ph.D., Mary S. Wolff, Ph.D. Support: Health Research Council: U-1272. Research Fellowship Award - ES 02565 Career Scientist Award - ES 44S12 Period: 1973 Table I PERSONAL SAMPLES - AUTOMOBILE BRAKE SERVICE Operation Distance Concentration (fibers/ml.) Blowing dust out of drum brakes It If It |t ft f VI tl t fr If If ?9 * ft VI 1 11 11 ft Vi II 11 It 1* Ii It If It It VI r ft 11 VI If 3-5 ft. II VI 5-10ft. 11 II 10-20ft. n 13.6 29.4 6.6 13.6 3.6 2.0 4,2 0.4 4.8 BACKGROUND SAMPLES - AUTOMOBILE BRAKE SERVICE Ooeration Disxance from Operation Time Lapse Concentration (fibers/ml.) Blowing: dust out of drum braices " .................................... " " " "" " " " " '* " '................................................................ " " ................................... 10 ft. 20 ft, 12 ft. 50 ft. 65 ft. 75 ft. 0 min. 0 min. . 5 min. 5 min. 7 min. 14 min. 0.3 . 0.6 0,2 0.1 0.1 0.1 Only fibers longer than 5^ were counted, by phase microscopy at 400x. \ SIZE DISTRIBUTION OF CHRYSOTILE FIBERS IX BRAKE DRUM DUST Fibers counted and sized at 42,000 X (all fibers have diameters from 250$ to 500$) Sample 750-1500$ 1500-2250$ 2250-3000$ 3000-3750$ Total 1 *40% 2 32 3 20 4 26 5 57 6 23 7 50 S 29 96 10 11 34% 23 25 37 17 9 26 30 41 6 11% 32 25 26 4 12 21 21 18 31 11% 7 - 12 2 17 10 31 96% 87 70 96 78 56 99 97 75 79 PERSONAL SAMPLES - TRUCK BRAKE SERVICE Operation Renewing used linings by grinding Concentration (fibers/ml.) 2.7 7.0 2.2 4.1 5.0 4.7 5.6 1.7 2.5 2.0 BACKGROUND SAMPLES - TRUCK BRAKE SERVICE Operation Distance Concentration (fibers/ral.) Background to grinding used linings 1 t ft it i n ir it n n t nn ft i* it i* ii ?i 10 ft. 10 ft. 25 ft. 25 ft. 60 ft. 1.2 1.7 1.0 0.6 0.2 PERSONAL SAMPLES - TRUCK BRAKE SERVICE Operation Concentration (fibers/ml.) Bevelling1 new linings n n * ii n ii i n it n ti 31.7 23.7 32.7 72.0 26.3 BACKGROUND SAMPLES - TRUCK BRAKE SERVICE Operation Distance Background to 11 11 |i f1 bevelling ft vi VI linings ft t* ft 8 ft. 12 ft. 12 ft. 30 ft. Concentration (fibers/ml.) 0.6 0.5 0.3 0.3 PERSONAL SAMPLES - TRUCK BRAKE SERVICE Operation Concentration (fibers/ml.) Punching rivets into brake lining f. - .. M ,, Chipping rust off used brake driers Sweeping floor around grinder Background taken 15 ft. away during sweeping 1.9 20 2.4 3.6 3.1