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INDUSTRIAL HYGIENE ASSESSMENT OF SEVEN BRAKE SERVICING FACILITIES ASBESTOS Paul Johnson Ralph 0. Zunwalde Dennis Roberts January 29, 1979 Industrial Hygiene Section Industry-wide Studies Branch Division of Surveillance, Hazard Evaluations, and Field Studies National Institute for Occupational Safety and Health Cincinnati, Ohio SCF-ALLF-07547 4* INTRODUCTION A major objective of the National Institute for Occupational Safety and ' Health (NIOSH) is to determine environmental exposures of working pop- .~ ulations through research,surveys, and industrywidestudies. Accord' ingly, NIOSH is presently conducting research to characterize dust ex- posure resulting from vehicle brake servicing operations. Of particular interest are the small diameter, potentially respirable asbestos fibers generated by these operations. Limited studies have suggested that such emissions may be associatedwith asbestos-induced diseases.1 An estimated workforce of 900,000 brake mechanics and garage workers in 2 the U.S. are potentially exposed to asbestos. An estimated 118 million pounds of asbestos are used annually in the U.S. for the production of brake friction materials.3 In addition to asbestos, other materials which are used in the manufacture of b^ake linings such as lead, zinc, copper, and iron pose other potentials for exposures. Rohl and Langef identified thirty materials or compounds that make up the binders, fibeT reinforcers, and the property modifiers as being present during brake lining manufactur- : ' j : | ; I j j I | > 1 I SELECTION OF FACILITIES SURVEYED ,, The purpose of the study was to investigate and characterize dust exposures resulting from vehicle brake maintenance and repair operations taking into account the work practices utilized. Therefore, it was necessary to locate facilities where brake servicing operations were performed in different manners (i.e. equipment used, number of vehicles serviced, personal pro tection, etc.)* Six of the seven sites selected for the investigation were automobile brake service facilities which performed from 2 to 4S brake jobs per week at an average of 65 minutes per vehicle. At the seventh site studied, a truck service center, brake servicing took six to nine hours per vehicle with an average of three brake jobs per week. De tailed airborne dust sampling surveys were conducted at each facility. Description of Brake Servicing Operations The servicing parameters found at each facility were basically as follows. The vehicle is driven into a repair stall or bay for a brake system ex amination. Pending repairs, the wheels are elevated, removed, and then inspected. Loose dust is cleaned from the drums and brake assemblies by vacuuming, wiping, brushing, using compressed air, or a combination ef these methods. Parts are then replaced or repaired as needed and the brake system is reassembled and adjusted. Test driving the vehicle for proper fitting and adjustment is the final phase of the servicing opera tion. A brief description of the individual facilities is outlined as follows: Facility A This facility, a fleet service garage, was responsible for complete auto motive maintenance and reaplr with the exception of internal engine repaiT -2- and exterior painting. The shop normally operates eight hours per day, five days per week. Of the seven employees working at the facility, only three are full-time bTake mechanics. Brake servicing operations were performed (an average of two to five jobs per week) in either of two service stalls. Facility B Although Facility B was an automobile brake service shop, front-end align ment and tire sales were also part of the shop mechanics' duties. The three full-time mechanics worked from.two service stalls, 12 hours per day days per week. Brake maintenance operations consisted of 10 to 14 jobs per week. Facility C . Major services: at this automobile brake service shop consisted of front- end alignment, shock absorber servicing, arid brake maintenance. The nor mal work week was made up of five, nine-hour days and one, six-hour day. Three service stalls were used by the three full-time employees for brake servicing operations. Brake servicing averaged four to six jobs per week. Facility D Major services provided at this auto brake shop were front-end alignment, shock absorber service, and brake maintenance. The three full-time employees worked from two service stalls, 9-hours per day, six days per week. The number of brake jobs averaged 20 to 30 per week. -3- Facility E Plant E was the largest of the automobile brake service shops surveyed. Other services provided by this facility were front-end alignment and shock absorber replacement or repair. The five full-time mechanics worked from four service stalls, nine hours per day, six days per week. Brake maintenance operations consisted of 35 to 45 jobs per week. Facility F The major services at this facility were front-end alignment, muffler installation, and brake maintenance. Automobile brake repair operations were performed by the shop's three employees and consisted on the average of four to five brake jobs per week. Normal brake servicing at this facility took about 1 hour and 45 minutes per vehicle.' Facility G This shop, a truck brake maintenance facility, involved a somewhat differ ent operation and exposure. Servicing operations were more complex and, therefore, involved more employees and fewer vehicles serviced. The four service bays at the facility were used by seven mechanics. Other service operations included pad grinding, riveting, and punching (pad removed and/or replaced on shoe), sand blasting of old shoes, and milling of wheels. Sampling and Analysis . Personal and general air samples were collected at each facility on differ ent occasions during a two-year period. Brake servicing operations, as well -4- as other areas within each facility were monitored to provide asbestos exposure data. Personal air samples were collected in the breathing zone of the brake mechanics using Millipore type AA, 37 mm diameter, 0.8 pm pore size, membrane filters at a sampling flow rate of 2.0 liters per minute (tpm). The filters were changed periodically during the work shift to prevent overloading of the collection media. Peak ex posures were determined by using Cast pumps calibrated at 11.0 and 10.6 tpm. These samples were collected on identical media as above but only during the time in which workers were cleaning dust from the brake drums and assemblies. Analysis of the membrane filters for asbestos fibers was conducted in accordance with the procedures outlined 4* by the Occupational Safety and Health Administration and the NIOSH Manual of Analytical Methods P 8 CAM #239.5 These procedures require the counting of fibers greater than S micrometers in length and require the counting of fibers greater than 5 micrometers in length and with at least a 3 to 1 length to width ratio using phase contrast optical micro scopy at a magnification of 400-4S0X. Random samples from each facility surveyed, as well as those samples having high fiber concentrations, as determined by the optical counting method, were analyzed on a transmission electron microscope utilizing selected area electron diffraction and an energy dispersive X-ray analyzer. Sample preparation and analysis were performed in the manner described in the NIOSH Technical Report, "Review and Evaluation of Analytical Methods for Environmental Studies of Fibrous Particulate Exposure".** -5- Samples were observed at 17.000X magnification with fibers (> 3:1 aspect ratio) sized by length and diameteT. Selected area electron diffraction (SAED) was attempted on all observed fibers for possible identification. In addition, energy dispersive X-ray analysis was performed on individual fibers to determine their elemental composition. Airborne samples collected at Facilities E and G were analyzed for trace metals by atomic absorption spectrophotometry in accordance with the N10SH Manual of Analytical Methods, Volumes 1 and 3.^'7 RESULTS Facility A . Fibrous dust concentrations (fibers > 5 ym in length) found at Facility A, a fleet grage, were similar to those found in passenger car brake ser vice shops. A time-weighted average (TWA) concentration of 0.12 fibers/cc was found for one mechanic from the personal samples collected. General area airborne samples indicated a range of concentrations from 0.02 to 0.07 fibers/cc in the brake service area (Table 1). Facility B A TWA concentration of 0.12 fibers/cc was found for a mechanic. Two general area samples collected near the servicing of brakes indicated con centrations of 0.09 and 0.13 fibeTs/cc (Table 2). Facility C A TWA concentration of 0.03 fibers/cc was found from the personal samples -6- collected for a brake mechanic. General area sample concentrations ranged from 0.01 to 0.17 fibers/cc (Table 3). A three minute sample collected near a mechanic while cleaning a brake drum using compressed air resulted in a peak concentration of 1.82 fibers/cc. Facility D The TWA concentrations for brake mechanics I and II at Facility D were 0.15 fibers/cc and 0.10 fibers/cc, respectively. General area sample concentrations ranged from 0103 to 0.14 fibers/cc for samples collected at various locations within the facility (Table 4). Facility E The sample results from the 1976 survey conducted at Facility E indicated personal TWA exposures of 0.08, 0.12, 0.07 and 0.10 fibers/cc for the four brake Mechanics. General area sample concentrations ranged from 0.04 to 0. 19 fibers/cc (Table 5-A). Air samples were also collected at this facility in 1977 during a five- day period (Table 5-B). Sample results indicated TWA exposures for Mechanic 1, 11, III and the Partsman to be 0.18, 0.07, 0.11 and 0.11 fibers/cc, re spectively. These exposure concentrations represent a time-weighted average for all personal samples collected during the 5 day period. TWA concentra tions for general area samples collected during the week ranged from 0.05 to 0.06 fibers/cc. Short duration samples 30-60 seconds) were collected to determine peak exposure concentrations to asbestos dust during the servicing of brake shoes. .. -7- Peak concentrations ranged from 0.45 (dry brush cleaning) to 14.54 (compressed aiT cleaning) fibers/cc. Facility F Personal samples collected from two mechanics at Facility F (Table 6) indicated exposures of 0.02 and 0.03 fibers/cc, respectively, while the one general area sample had a concentration of 0.01 fibers/cc of air. Facility G Facility G, which was surveyed in 1976 and again in 1977, was involved in the maintenance of truck brakes. Worker exposures tended to be some what different as the servicing was more complex and the- number of vehicles serviced peT day much less. However, due to larger wheels and drums, the brake pad replacement operation made it difficult for the workers to avoid the generated airborne dust, Consequently, the exposures were higher than those found during automobile brake maintenance. Personal samples collected during the first survey in 1976 (Table 7-A) compared similarly to those sample results found at the auto brake ser vice shops. The TWA concentration for brake mechanic I was 0.05 fiber/cc while the concentration for mechanic II was 0.18 fiber/cc. The second survey conducted in 1977 (Table 7-B), however, was found to be distinctly higher. The concentration for brake mechanic I was 1.68 fibeTs/cc, for mechanic II, 0.53, and for mechanic III, 0.52 fibers/cc of air. General area samples collected in the 1976 survey indicated concentrations which ranged from 0.03 fibers/cc in the eating area, 0.03 to 0.11 fibers/cc in -8- the bay areas and "0.12 to 1.18 fibers/cc in the Relining Department. In contrast, general area samples collected in 1977 at this facility indicated the following range of concentrations; Office - 096 to 1.68 fibers/cc; Garage (east side) - 0.26 to 1.72 fibers/cc; Garage (west side) - 0.24 to 1.71 fibers/cc. It is readily noted that these con centrations are higher than those of the general area sample results found at the auto brake service shops. The areas of highest exposure concentrations at the tmck brake service shop appear to be in the vicinity of the rivet, punch, And pad grinding operations. The rivet operator's TWA concentrations were 3.41 fibers/cc (1976) and 4.47 fibers/cc (1977), while that of the punch operator was 0.68 fiber/cc (1976) and 7.52 fiber/cc (1977). Metal Analyses Trace metal analyses were performed on airborne samples collected during the 1977 survey at Facility E (Table 8) and at Facility G (Table 9). Samples were analyzed for trace amounts of the following metals: lead, iron, zinc,'chromium, nickel, cobalt, copper, manganese, and aluminum. As noted in Tables 8 and 9 most of the metals were either non-detectable or found in trace amounts. Fiber Characterization Samples selected for transmission electron microscopy (TEM) were sized by length and diameter and fiber concentrations (fibers/cc) determined for total fibers and fibers > 5 ym in length. These concentrations were -9- compared to those found by the optical microscopy method and are reported in Table 10. In all but 3 samples, fiber concentrations (> 5 urn) deter mined by phase contrast optical microscopy were somewhat higher than those determined by TEM. This difference could have been caused by particulate loss during the preparation of samples for TEM. Another factor which may reflect the difference found in sample comparisons is the small number of fibers observed on each sample. Small differences in the number of fibers counted by both methods would produce significant differences in concentrations. Besides determining the concentrations for fibers > S pm in length, total fibers observed were counted and concentrations calculated. As would be expected, the greatest number of fibers observed were shorter than S ym in length (82%). In addition to fiber sizing and counting, identification was attempted on all fibers utilizing selected area electron diffraction (SAEO) and energy dispersive X-ray analysis. Approximately 50% of the fibers analyzed by SAED could not be identified due to ambiguous diffraction patters. The remaining fibers were identified as chrysotile (30% and forsterite (20%). When energy dispersive X-ray analysis was performed on the fibers, con firmation of the SAEO analysis was made for the chrysotile and forsterite fibers. Those fibers which revealed ambiguous SAED patterns were either too small for diffraction analysis or had undergone elemental changes prob ably as a result of intense heat. The elemental composition of some of -10- hese fibers appeared to indicate a stage of metamorphosis between chrysotile and forsteTite. DISCUSSION Airborne asbestos sample results for all facilities appear to be within the current OSHA asbestos standard. This standard states: "The 8-hour time-weighted average (TNA) airborne concen tration of asbestos fibers to which any employee may be exposed shall not exceed 2 fibers, longer than S micro meters in length, per cubic centimeter of air (fibers > 5 ym/cc). The ceiling airborne concentration to w)\ich no employee may be exposed shall not exceed 10 fibers > 5 ym/cc." However, when the results are compared to the NIOSH recommended standard, in which the 8-hour TNA exposure to asbestos is 0.1 fibers > 5 ym/cc with a ceiling exposure of 0.5 fibers > 5 ym/cc for any 15 minute samling period, many of the exposures to brake servicing mechanics indicate concentrations which exceed these recommendations. Although most of the reported TNA exposures are based on sampling times less than 8 hours, (usually 3 to 8 hours) the randomness of the sample collection throughout the work day at each facility suggests a consistent range of exposure concentrations fox any given operation. These Tanges of exposure appear to be dependent upon the work practices utilized in servicing brakes. It is readily apparent that compressed air cleaning, and to a lesser extent -11- dry cleaning can produce peak exposures which exceed both the OSHA standard and the NIOSH recommended standard. The airborne exposures found at these facilities compare favorably to studies performed by other investigators. Studies by Lorimer et al1 and 2 Rohl et al reported peak concentrations to asbestos fibers ranging from 6.6 to 29.8 fibers/cc when compressed air cleaning was used. In addition, the elevated exposures found during the use of dry brush cleaning in Facility E (0.45 - 0.91 fibers/cc) were likewise substantiated by Rohl et al 2 study in which the y found exposure s ranging from 1.3 `- 3.6 fibers/cc. The one truck brake servicing facility (G) surveyed indicated high asbestos fiber exposures during the riveting and grinding of truck brake shoes (0.68 7.52 fibers/cc). A similar magnitude of exposures were found by LorimeT et al1 in which workers beveling truck brakes were exposed to concentrations of 26.3 to 72.0 fibers/cc. The practice of refurbishing and custom fitting brake shoes in automobile brake servicing facilities appears to be limited. However, the need for custom fitting of brake shoes in the truck servicing facilities is often necessary. As demonstrated, the exposures found in refurbishing truck brakes add greatly to.the asbestos dust burden of the worker. The electron microscopy (EM) analysis performed on selected air samples indicates that a majority of the airborne fiber exposures consist of small fibers ( < 5 |in in length and < 1 pm in diameter). These results were -12- confirmed by studies of Rohl et al 2 , Lorimer et al 1, and 8Lynch in which they found 80-90% of the fibers observed by EM to be below'the resolution of the optical microscope. The results of the EM analysis also suggests that many of the chrysotile fibers released during braking had undergone a decomposition phase and changed both physical and chemical characteristics to that of forsterite. These findings were supported by the study of Lorimer et al.* The human toxicological siginficance for the inhalation to chrysotile fibers is well documented. However, the health effects of exposure to forsterite, or transition fibers of chrysotile-forsterite are not well documented. In studies by Davis and Coniam9 and Koshi10 *in which fibers of chrysotile, chrysotile-forsterite, and forsterite were injected into the pleural and peritoneal cavities of mice the results suggest varying degrees of toxic effects for all types. The mechanism responsible for these observed toxic effects is unclear, but animal studies by Pott et al11'12 and David et al*3 indicate that the morphology and sire of the fiber are responsible for its carcinogenicity. It is suspected by Pott et al*2 that a fiber with a diameter < 1 um and a length > 3 pm has the greatest carcinogenic potential, likewise, Stanton et al14 sug gests that fibers < 1.5 pm in diameter and > 8 \m in length pose the greatest risk in producing pleural sarcomas. -13 CONCLUSION Results of this study and of other studies indicate varying concentrations of asbestos fiber exposures which appear to be dependent upon the type of brake servicing operation and work practices utilized. It is apparent that when brake shoes are beveled, ground, riveted, etc. that exposures to asbestos fibers can be quite high. Likewise, exposures generated during the cleaning of brake shoes and drums with compressed air and dry brush methods can be high for short durations of time. NIOSH has undertaken a comprehensive industrial hygiene study to address the following areas: 1. Document work practices (i.e. protective clothing, re spirator protection, eating and smoking practices, etc.) 2. Document the use of engineering controls (i.e. vacuum cleaners, local exhaust ventilation, etc.) 3. Document housekeeping practices (i.e. disposing of old brake and clutch materials, rags, etc.) 4. Determine 8-10 hour TWA exposures and peak exposures to workers as determined by the different work practices (i.e. compressed air, dry and wet bnishing, etc.) utilized while engaged in brake servicing operations. 5. Characterize and identify airborne fiber exposures using optical and transmission electron microscopy. . -14- Based on the data from other studies and the data from this study demonstrating significant asbestos exposures during brake servicing operations, NI05H has published interim procedures, "Recommended Procedures for Asbestos Brake and Clutch Servicing" to minimize asbestos dust exposures.These recommended procedures are periodi cally updated as research data and engineering controls become avail able. -15- REFERENCES 1. Lorimer, W.V., Rohl, A.N., Miller, A., Nicholson, N. J., and Selikoff, I.J. "Asbestos Exposure in Brake Repair Workers in the United States". Mt. Sinai Journal of Medicine, 43: 207-218, (May-June 1976). 2. Rohl, A.N., Langer, A.M., Wolfe, M.S., and Weisman, I. "Asbestos Exposure.During Brake Lining Maintenance and Repair". Environmental Research, Volume 12, 110-128, (1976). 3. Jacko, M.G., and Ducharme, R.T. (1973), "Brake Emissions: Emission Measurements from Brake and Clutch Linings From Selected Mobile Sources", U.S. National Technical Infor mation Service, PB-222-372.. 4. U.S. Code of Federal Regulations, Title 29, Part 1910.1001. U.S. Department of Labor, Occupational Safety and Health Administration, Occupational Safety and Health Standards. 5. Taylor, D.G., (1977). NIOSH Manual of Analytical Methods. 2nd Edition, Volume 1, P | CAM No. 239, Publication No. 77157-A. 6. Zumwalde, R.D., and Dement, J.M., (1977). Review and Evalu ation of Analytical Methods for Environmental Studies of Fibrous Particulate Exposures. DHEW (NIOSH) Publication No. 77-204. 7. Taylor, D.G., (1977). NIOSH Manual of Analytical Methods. 2nd Edition, Volume 111, Publication Ho. 77-157. 8. Lynch, J.R. Brake Lining Decomposition Products, Journal Air Pollution Control Association, Volume 18, No. 12, pp. 824-826 (1968). 9. Davis, J.M.S., and Coniam, S.W. Experimental Studies on the Effects of Heated Chrysotile Asbestos and Automobile Brake Lining Dust Injected into the Body Cavities of Mice, Experimental and Molecular Pathology, Volume 19, pp. 339-353 (1973). 10. Koshi, K., Hayashi, H., and Sakabe, H. Biological and Mineralogical Studies on Serpentine Minerals in Heat Treated State, Ind. Health, Volume 7, pp. 66-85 (1969). 11. Pott, F., Huth, F., and Friedricks, K.H. Tuaorigenic Effect of Fibrous Dust in Experimental Animals. Environmental Health Perspectives, Volume 9, pp. 313-315 (1974). 12. Pott, F., Dolgner, R., Friedricks, K.H., and Huth, F. Animal Experiments Concerning the Carcinogenic Effect of Fibrous Dusts. Interpretation of Results Considering the Carcinogenesis in Humans. Annales d'Anatomie Pathologique, Paris, (1976), Volume 21, pp. 237-246. 13. Davis, J.M.6. The Fibrogenic Effects of Mineral Dusts Injected into the Pleural Cavity of Mice, British Journal Exp. Pathology, Volume 53, pp. 190-201, (1972). 14. Stanton, M.F., Layard, M., Tegeris, A., Hiller, E., May, M., and Kent, E. The Carcinogenicity of Fibrous Glass: Pleural Response in the Rat in Relation to Fiber Dimension. J. Natl. Cancer Institute 58:587-603, (March 1977). 15. "Recommended Procedures for Asbestos Brake and Clutch Servicing" Division of Surveillance, Hazard Evaluations, and Field Studies, N10SH. Updated November, 1978. Table 1 Facility A Automobile Fleet Garage Fiber Air Sample Results Optical Microscopy Operation Brake and Front End Mechanic Sample # B-104 B-99 B-102 General Area Right Front Left Center Right Front Shop B-105 B-98 B-101 B0103 Volume (liters) 30 1S2 160 Concentration Fibers > S ym/cc 0.15 0.16 0.07 TWA 0.12 120 . 262 216 232 0.03 0.02 0.07 0.03 TNA - Time-Weighted Average exposure for period of time samples Table 2 Facility B Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Sample Location Brake Mechanic General Area near brake servicing operation Volume (liters) 758 190 312 282 Time (min.) 379 95 156 141 Concentration Fiber > 5 im/cc 0.10 0.15 0.12 0.09 0.13 TWA = Time-Weighted Average exposure for period of time sampled Table 3 Facility C Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Type Sample Volume (liters) Time (min) Concentration Fibers > 5 pm/cc Personal 01 compressed air/ cleaning drums 02 03 04 General Area East Front North Side North Side South Side East Front South Side South Side 6 164 174 306 548 546 186 122 196 142 471 3 22 87 243 - 274 282 98 61 98 71 23S peak 1.82 0.07 0.05 0.02 TWA 0.03 0.01 0.01 0.02 0.17 0.05 0.02 0.01 TWA - Time-Weighted Average exposure for period of time sampled Table 4 Facility D Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Operation Concentration Sample 9 Volume (liters) Time (min) Fiber > 5 pm/cc Brake Front End Mechanic I 11 B-38 B-37 B-46 B-36 B-51 B-44 B-39 General Area W. Back Wall E. Front N. Side W. Back Wall S. Side E. Front N. Side W. Back Wall S. Side N. Side E. Front B-40 B-41 B- 42 B-50 B-49 B-48 B-47 B-32 B-43 B-34 B-3S 50 28 106 76 72 4 214 98 50 64 82 82 82 84 130 82 116 136 25 14 53 38 36 2 ' 107 49 25 32 41 41 41 42 65 41 58 68 0.03 0.37 0.14 TWA 0.15 0.21 0.05 2.33 0.04 TWA 0.10 0.09 0.03 0.09 0.06 0.07 0.14 0.04 0.12 0.13 0.13 0.05 TWA - Time-Weighted Average exposure for period of time sampled Table 5-A Facility Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Operation Brake & Front End Mechanic 1 Sample i B-3 B-ll B-30 B.-22 Volume (liters) 440 104 50 92 Time (min) 220 52 25 46 Concentration Fibers > 5um/cc 0.06 0.07 0.12 0.14 TWA 0.08 II B-l 466 233 0.05 B-2 252 126 0.07 B-19 80 40 0.12 B-29 52 26 0.27 B-12 72 36 0.58 TWA 0.12 III B-9 210 105 0.13 B-27 72 36 0.11 B-13 284 142 0.02 TWA 0.07 IV B-10 208 104 0.03 B-18 42 21 0.33 B-20 240 120 0.12 B-8 102 51 0.12 TWA 0.10 General Area Stall 4 Stall 5 Stall 1 Stall 5 Stall 2-3 B-25 B-7 B-14 B-26 B-24 84 452 102 60 128 42 0.19 226 0.07 51 0.10 30 0.10 64 0.08 Operation General Area Stall 1 Stall 5 Stall 4 Stall 2-3 Stall 4 Stall 1 Stall 2-3 Shop Wall S.E. Corner Table 5-A (continued) Sample # Volume (liters) Time (min) Concentration Fibers > Spn/cc B-23 B-17 B-16 B-15 B-6 B-4 B-5 B-33 B-31 130 104 104 . 102 444 462 454 100 40 65 52 52 51 222 231 227 50 . 20 0.19 0.10 0.09 0.07 0.03 0.04 0.08 0.05 0.15 TWA - Tine-Weighted Average exposure for period of (line sampled Sample Location (Personal) Brake Mechanic I Brake Machanic II Brake Machanic III Partsman (General Area) Office Southside Table 5-B Facility E Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Day of the Week No. of Samples Collected Time-Weighted Average (TWA) Range of Concentration Concentrations by Day Fibers > 5 um/cc Fibers > 5 um/cc TWA by Week 1 3 0.05 - 0.1 0.07 2 4 0.02 - 0.26 0.12 3 3. 0.09 - 0.15 0.20 0.18 4 2 0.05 - 0.06 0.05 S 1 0.01 - 0.01 0.01 1 3 0.03 - 0.09 ' 0.07 2 3 0.04 - 0.13 0.09 3 3 0.01 - 0.27 0.18 0.07 4 3 0.06 - 0.10 0.08 5 3 0.01 - 0.04 0.02 1 3 0.03 0.06 0.04 2 3 0.08 - 0.29 0.12 3 4 0.07 - 0.38 0.14 0.11 4 5 0.07 - 0.24 0.16 5 2 0.15 - 0.19 0.17 1 1 0.06 - 0.06 0.06 2 2 0.03 - 0.78 0.09 3 3 0.01 - 0.30 0.15 0.11 4 4 0.07 0.24 0.16 S 3 0.01 - 0.06 0.03 1 2 0.03 - 0.18 2 2 0.01 - 0.02 3 2 0.12 - 0.18 4 2 0.03 - 0.05 5 2 0.01 - 0.07 1 8 0.01 - 0.11 2 7 0.02 - 0.25 3 6 0.01 - 0.32 4 10 0.00 - 0.14 5 2 0.01 - 0.01 0.10 0.02 0.17 0.04 0.03 0.05 0.11 0.05 0.06 0.01 0.06 0.06 Table 5-B (continued) Sample Location Northside (Peak) Cleaning with Compressed Air Day of the Week 1 2 3 4 5 1 2 No. of Samples Collected Range bf Concentrations Fibers > S ym/cc Time-Weighted Average (TWA) Concentration by Day Fibers > 5 ym/cc TWA by Week 6 0.01 - 0.06 6 0.03 - 0.14 7 0.00 - 0.39 8 0.01 - 0.13 4 0.01 - 0.07 0.05 0.06 0.06 0.05 0.04 0.05 -- -- 1 2.84 N/A N/A Dry Brush Compressed Air 0.45 3 2 0.68 Dry Brush - Compressed 4 2 0.91 Air 5 -- 14.54 N/A N/A N/A N/A TWA - Time-Weighted Average exposure for period of time sampled Sample Number Mechanic B1 (Personal) Mechanic B2 (Personal) B3 (Area) Table 6 Facility F Automobile Brake Shop Fiber Air Sample Results Optical Microscopy Volume (liters) 360 196 150 Time (min) 180 98 85 Concentration Fibers > 5 pm/cc 0.02 0.03 0.01 Table 7-A (1976) Facility G i Truck brake Shop Fiber Air Sample Results Optical Microscopy Operation Sample 1 Volume (liters) BRAKE REBUILDING Brake Mechanic I - B-69 B-75 B-87 B-92 102 158 194 152 II B-60 52 B-63 84 B-57 60 B-79 122 B-88 194 Time (min) 51 79 97 76 26 42 30 61 97 Concentration Fibers > Spm/cc 0.09 . 0.07 0.03 0.03 TWA 0.05 0.09 0.72 0.15 0.17 0.03 TWA 0.18 RELINING DEPARTMENT Rivet Operator II 1 . ff II II II 1 B-67 B-81 B-96 B-89 B-84 B-78 B-72 B^57 B-58 50 76 138 176 168 62 60 112 42 25 1.59 38 0.38 69 5.62 88 3.64 84 0.19 31 3.34 30 6.00 56 6.79 21 6.52 TWA 3.41 Punch Operator B-61 B-66 B-71 B-77 72 50 60 62 36 0.18 25 0.97 30 0.56 31 0.78 Table 7-A (1976) (continued) Operation Punch Operator II If Sample t B-95 B-80 B-97 Volume (liters) 152 74 138 Concentration Time (min) Fibers > Spm/cc 76 0.24 37 0.70 69 0.79 TWA 0.68 GENERAL AREA Eating Area II B-55 B-94 224 162 112 0.03 81 0.03 1st and 2nd Bay II II It II B-54 B--64 B-65 B-74 B-91 B-56 120 248 246 350 64 120 60 124 123 175 32 60 0.05 0.03 0.05 0.06 0.05 0.11 TWA 0.06 Relining Department 1 II II II . II II B-53 B-62 B-68 B-76 B-93 B-86 B-70 88 72 48 106 312 172 148 44 0.39 36 1.18 24 0.54 53 0.20 156 0.18 86 0.12 74 0.15 TWA 0.28 TWA - Tine-Weighted Average exposure for period of tine sampled Table 7-B (1977) Facility G Fiber Air Sanple Results Optical Microscopy Operation/Area BRAKE REBUILDING Brake Mechanic I Brake Mechanic II Brake Mechanic III RELINING DEPARTMENT Rivet Operator Punch Operator Partsman Sample # D-3 D-8 D-13 D-4 D-7 D-15 D-2 D-6 D-9 D-10 D-14 D-12 D-16 D-17 D-5 Volume (liters) 240 246 280 184 512 272 160 184 106 168 296 100 126 66 400 Time (min) Concentration Fibers > Swn/cc 120 1.09 123 3.24 140 0.804 TWA 1.68 92 0.289 256. 0.62 TWA 0.53 136 0.52 80 2.0 92 5.59 53 7.53 84 6.84 148 2.68 TWA 4.47 50 7.31 63 5.90 33 10.92 TWA 7.52 200 1.21 Operator/Area GENERAL AREA Office Garage (East) Garage (West) Table 7-B (1977) (continued) Sample t Volume (liters) Time (min) Concentration Fibers > Sym/cc D-l D-ll 490 440 245 1.68 220 0.96 C-l C-4 C-6 c-e c-n C-14 664 847 529 1366 1010 269 69 0.46 88 0.33 55 1.72 142 0.82 105 0.46 28 0.26 C-2 C-3 C-5 C-7 C-10 C-12 C-13 740 773 640 574 585 927 298 67 0.65 70 0 76 58 1.44 52 1.71 53 1.30 84 0.49 27 0.24 Table 8 Facility E Automobile Brake Shop Air Sample Results Trace Metal Analysis Sample Number A-16 A-17 B-15 B-17 A-21 A-27 B-10 A-8 B-ll A-74 A-76 A-83 A-46 A-91 B-63 B-73 B-64 A-87 B-70 B-81 A-99 B-65 Volume (liters) 670 809 92 880 756 373 450 756 234 8.0 259 346 605 486 480 276 326 373 262 124 320 220 Location of Sample General Area Northslde General Area Southside Brake Mechanic I General Area Office General Area Southside General Area Southside General Area Office General Area Northslde Brake Mechanic ill Dry Brush Cleaning General Area Northslde General Area Northslde General Area Northslde General Area Northslde General Area Office Brake Mechanic III Partsman General Area Southside . Brake Mechanic II Brake Mechanic III General Area Southside Brake Mechanic II Trace Metals mg/filter sample Fe Fb Zn 17.0 8.0 < 1.0 30.0 11.0 < 1.0 7.0 < 5.6 < 1.0 9.0 < 5.0 < 1.0 27.0 < 5.0 < 1.0 16.0 < 5.0 < 1.0 < 5.0 < 5.0 9.0 < 5.0 < 5.0 < 1.0 13.0 < 5.0 3.0 65.0 < 5.0 < 1.0 16.0 < 5.0 < 1.0 14.0 6.0 < 1.0 33.0 8.0 < 1.0 33.0 8.0 < 1.0 7.0 6.0 < 1.0 29.0 8.0 < 1.0 29.0 < 5.0 < 1.0 22.0 < 5.0 26.0 < 5.0 < 1.0 < 5.0 < 5.0 < 1.0 < 5.0 11.0 < 1.0 ........ 17.0 < 5.0 < 1.0 o H V Sample Number A-88 A-92 A-93 B-57 B-48 B-82 A-89 B-72 B-53 A-97 B-71 A-84 B-80 8-77 0-68 B-54 A-86 B-59 A-71 B-58 B-46 B-43 B-78 Volume (liters) 320 533 670 164 200 90 324 228 170 324 120 972 144 334 216 270 616 220 810 206 214 106 184 Table 8 (continued) Facility E Automobile Brake Shop Air Sample Results Trace Metal Analysis Location of Sample . General Area Southside General Area Southside General Area Northslde Part6man Brake Mechanic III General Area Office General Area Northslde Partsman Brake Mechanic II General Area Northslde Brake Mechanic III General Area Northslde Brake Mechanic II Brake Mechanic II Brake Mechanic I Brake Mechanic HI General Area Northslde Brake Mechanic I General Area Northslde Partsman Partsman . Partsman Partsman Trace Metals mg/filter sample Fe Pb Zn 52.0 <5.0 <1.0 37.0 9.0 <1.0 17.0 16.0 1.0 32.0 < 5.0 1.0 28.0 6.0 3.0 < 5.0 < 5.0 <1.0 33.0 ' < 5.0 <1.0 13. O' < 5.0 <1.0 23.0 < 5.0 <1.0 12.0 < 5.0 <1.0 8.0 6.0 <1.0 9.0 < 5.0 <1.0 < 5.0 < 5.0 <1.0 7.0 8.0 <1.0 59.0 < 5.0 <1.0 7.0 < 5.0 <1.0 15.0 9.0 <1.0 18.0 6.0 1.0 18.0 11.0 6.0 32.0 < 5.0 <1.0 43.0 < 5.0 2.0 8.0 < 5.0 <1.0 12.0 5.0 <1.0  :i Sample Number B-69 A-90 A-48 B-33 A-98 A-85 B-61 A-73 A-77 A-81 A-49 B-32 B-36 A-44 A-40 B-29 B-24 A-57 B-34 B-45 A-53 A-6 Volume (liters) 206 373 458 222 648 916 172 5.33 479 533 1015 364 334 670 469 172 502 618 226 652 8.0 648 Table 8 (continued) Tacility E Automobile Brake Shop Air Sample Results Trace Metal Analysis Location of Sample Trace Metals mg/fliter sample Pe Pb Zn Brake Mechanic Z 30.0 < 5.0 2.0 General Area Southslde 42.0 7.0 < 1.0 General Area Southslde 160.0 8.0 1.0 Partsman 31.0 5.0 1.0 General Area Northslde < 5.0 26.0 < 1.0 General Area Southslde 30.0 7.0 < 1.0 Brake Mechanic II Compressed Air Cleaning General Area Southslde General Area Southslde General Area Northslde Brake Mechanic II Brake Mechanic II General Area Northslde General Area Southslde Brake Mechanic III General Area Office General Area Southslde Brake Mechanic I General Area Office 17.0 36.0 43.0 30.0 21.0 22.0 18.0 25.0 9.0 23.0 14.0 33.0 30.0 19.0 8.0 < 5.0 13.0 13.0 11.0 7.0 6.0 < 5.0 16.0 5.0 21.0 6.0 < 5.0 9.0 < 1.0 2.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Dry Brush Cleaning 9.0 < 5.0 < 1.0 General Area Northslde 32.0 27.0 1.0 )I Il 1 Sample Number B-18 B-14 A-14 G-9 A-20 B-19 A-41 A-38 A-33 B-25 B-26 A-58 B-41 B-37 A-52 A-51 B-35 B-42 A-55 A-50 A-47 Table 8 (continued) Facility E Automobile Brake Shop Air Sample Results Trace Metal Analysis Volume (liters) 162 76 916 242 575 370 415 639 426 194 394 680 370 358 648 426 160 200 5.32 660 426 Location of Sample Brake Mechanic 11 Fartsman General.Area Southslde Brake Mechanic 1 General Area Southslde Brake Mechanic Z General Area Southslde General Area Southslde General Area Southslde Brake Mechanic I Brake Mechanic XI General Area Northside General Area Office Fartsman General Area Northside General Area Southslde Brake Mechanic III Brake Mechanic II Compressed Air Cleaning General Area Southslde General Area Southslde Trace Metals mg/filter sample Fe Fb Zn 24.0 < 5.0 <1.0 52.0 5.0 <1.0 21.0 8.0 <1.0 19.0 < 5.0 <1.0 39.0 13.0 <1.0 35.0 ' 10.0 <1.0 27.0 < 5.0 1.0 16.0 11.0 <1.0 50.0 < 5.0 <1.0 9.0 < 5.0 9.0 12.0 22.0 8.0 5.0 <1.0 <1.0 10.0 6.0 <1.0 17.0 7.0 <1.0 35.0 < 5.0 <1.0 45.0 < 5.0 <1.0 68.0 < 5.0 2.0 14.0 < 5.0 <1.0 34.0 < 5.0 <1.0 15.0 8.0 <1.0 39.0 9.0 2.0 Sample Number A-31 A-37 A-34 B-21 B-27 A-26 A-28 B-22 B-l B-16 A-10 B-3 B-8 A-9 A-12 B-7 B-5 Volume (liters) 543 648 616 840 108 400 554 388 188 72 950 198 204 415 426 292 280 Table 8 (continued) Facility E Automobile Brake Shop Air Sample Results Trace Metal Analysis Location of Sample Trace Metals mg/filter sample Fe Pb Zn General Area Southside 36.0 24.0 1.0 General Area Northside 9.0 41.0 <1.0 General Area Northside 22.0 < 5.0 <1.0 Partsman 14.0 < 5.0 3.0 Brake Mechanic I 21.0 < 5.0 38.0 General Area Northside 6.0 11.0 < 1.0 General Area Southside 11.0 19.0 9.0 Brake Mechanic II 7.0 * 5.0 < 1.0 Brake Mechanic III 14.0 < 5,0 ; < 1.0 Brake Mechanic III 18.0 < 5.0 12.0 General Area Northside Brake Mechanic I Brake Mechanic II General Area Southside 13.0 24.0 6.0 34.0 <5.0 < 5.0 < 5.0 10.0 4.0 2.0 < 1.0 2.0 General Area Southside < 5.0 8.0 < 1.0 Brake Mechanic I 24.0 8.0 < 1.0 Brake Mechanic II 12.0 8.0 1.0 56^ Note: Sample analyses for Mn, Al, Cr, Ni and Co were not detected. Limit of detection (pg) Lead Zinc Manganese Aluminum 5 ug 1 pg 2 yg 10 pg Chromium Nickel Cobalt Iron 2.5 5.0 5.0 5.0 pg Sample Number C-l C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-10 C-ll C-12 C-13 C-14 Volume (liters) 126 66 664 740 773 847 640 529 574 1366 585 1010 927 Table 9 Facility G Truck Brake Shop Air Sample Keaulta Trace Metal Analysis Location of Sample Trace Metals mg/filter sample Pb Fe Zn Mn Cu A1 Punch Oper, Punch Oper. Garage-Eastside Garage-Westside Garage-Westalde Garage-Eastside Garage-Westslde Garage-Eas tslde Gorage-Westslde Garage-Eastside Garage-rWestend Garage-Eastend Garage-Westend -- 16.0 16.0 10.0 10.0 6.0 < 6.0 6.0 -- -- -- -- 34,0 58.0 56.0 24.0 82.0 122.0 142.0 -- -- -- -- -- <1.6 < 1.6 <1.6 < 1.6 < 1.6 < 1.6 < 1.6 -- -- -- -- TT* 0,6 -- 1.0 1.6 -- 1.6 -- 2.6 -- 1.6 -- 2.0 -- 2.0 -- 2.0 -- -- 1.6 -- < 0.6 1.0 -- < 0.6 1,0 1.0 -- >-- -- -- -- -- -- <0.6 0.6 < 0.6 < 0.6 . J.. Sample Number D-l 0-2 D-3 D-A 0-5 0--6 0-7 D-8 D-9 0-10 0-11 0-12 D-13 D-14 0-15 Volume (liters) 490. 1601 240 3J34 40Q 184 512 246 1Q6 160 440 100 280 296 272 Table 9 (continued) Facility C Truck Brake'Shop Air Sample Reaulta Trace Metal Analysis Location of Sample ... Pb ' . Trace Metals mg/llter sample Pe Zn | Mn Cu A1 Office Area ' ' Rivet Oper. Mechanic 1 Mechanic IX Fartsman Rlyet Oper. Mechanic IX Mechanic X Rivet Oper. Rivet Oper. Office Area Funcb Oper. Mechanic X Rivet Oper, Mechanic XIX -- -- .-- -- -- 6.0 ~ 10,0 < 6.0 < 6.0 < 6.0 < 6.0 < 6.0 < 6.0 --r -- . ---- ---- -- -- t-- -- -- -- ---- 32.0 < 3.2 < 1.0 -- 154.0 -- " 3.2 1.6 148.0 < 3.2 1.6 13.0 < 3.2 < 1.0 15.6 2.6 < 1.0 20.0 1.6 * 1.0 96.0 2.6 1.6 16.0 1.6 * 1.0 0.6 0.6 1.0 1.0 0.6 1.6 -- 1.0 -- -- -- -- -- -- -- < 0.6 0.6 < 0.6 < 0.6 < 0.6 . 1.0 --. 1.0 . --. -- -- -- -- ~ Sample Number D-16 D-17 Volume (liters) 126 66 Table 9 (continued) Facility G Truck Brake Shop Air Sanple Results Trace Metal Analysis Location of Sample * Trace Metals mg/fllter sample Pb Pe Zn Mn Cu Punch Oper. Punch Oper. -- -- -- -- 0.6 -- -- "-- 1.0 A1 1.0 1.0 Note: Sample analyses for Cr, Ni and Co were not detected Limit of Detection (mg) Lead 6 mg Iron 5 mg Zinc 1.6 mg Manganese 1.0 mg Copper 0.6 mg Aluminum 0.6 mg Table 10 Fiber Air Sample Results Comparison Between TEM and Optical Microscopy Analysis Sample Number B-68 B-72 B-12 B-62 B-18 D-10 D-6 ; C-8 B-59 B-58 G-77 G-81 C-5 0-67 C-14 . C-13 B-32 C-22 : B-44 B-41 D-18 (Blank) B-37 B-79 C 0-63 0-9 r 0-68 Optical Microscopy Transmission Electron Microscopy- >5 ym in length fibers/cc >5 ym in length fibers/cc Total fibers fibers/cc Z Fibers >5 ym in length (TEM) 0.54 6.0 0.58 1.18 0.13 6.84 5.59 0.82 0.01 0.01 0.02 0.38 1.44 0.01 0.26 0.24 0.06 0.12 0.01 0.03 0.0 0.12 0.17 0.18 0.06 0.12 0.25 5.97 0.17 0.67 0.10 0.07 0.33 0.02 0.0 0.0 0.19 0.16 0.0 0.0 0.09 0.04 0.0 0.01 0.0 0.0 0.0 0.42 0.10 0.14 0.05 0.50 0.50 11.33 1.01 2.35 0.74 0.43 0.39 0.02 0.11 0.0 2.72 0.48 0.08 1.43 0.09 0.16 0.0 0.01 0.03 0.0 0.0 0.86 0.20 0.43 0.15 0.73 50 53 17 29 14 17 - 83 100 0 0 14 33 0 0 100 25 0 100 0 0 0. 33 33 25 40 41