Document NxvYYnOJ7jy0azBkMq8m49MR

CASE HISTORY 5 MANVILLE TEXTILES PLANT PLAINTIFF'S EXHIBIT DUP-10I2 We have chosen to review our duet control efforts at this location in order to dencnstrate the difficulty of controlling asbestos fiber emissions in asbestos textile manufacturing operations. The Manville textile operation began about 192C. Oust surveys to determine asbestos dust levels in the plant were performed intermittently from the mid 1930's to the mid 1950's by industrial hygienists from our insurance carriers. Unfor tunately, no records of these survey results presently exist. In 1958, Johns-Manville established an industrial hygiene laboratory at this location. The initial survey to monitor asbestos dust levels in the textile operation was done that year, using the impinger technique. Results of this first J-M survey were: Stations Monitored Ho. above TLV of 5 mppcf mppcf 203 36 27.2 0.4 As a result of this survey, programs were undertaken to reduce exposure levels. These programs were directed at improving existing manufacturing equipment by such means as increased dust control facilities, added vacuum cleaning systems, and revised work practices. By the yardstick of the period, our efforts were successful. Our last survey by the impinger method done in 1968 had the following results: No. of Work _ Stations Monitored No. above TLV of 5 mppcf High Low mppcf 157 1 6.1 0.2 In February 1969, we made our first industrial hygiene survey at this location utilizing the membpane filter/personal air sampler monitoring technique. The results astounded and dismayed us. They were: No. of Work Ho. of Stations over ACGIH High Low Stations Monitored proposed TLV of 5 f/cc f/cc 89 80 32.9 1.7 We immediately instituted a program to further reduce airborne concentrations of asbestos fibers. The first step was the forma- (38) DU 061845 tion of a task force which included representatives from plant management, environmental control, industrial engineering and ganaral plant anginaaring. Much affort including numerous falsa staps, wara axpandad during tha coursa of tha naxt four years. By tha and of that pariod wa had raducad tha fiber counts to levels ganarally balow 2.0 f/cc. This achievement raquirad: 1. Approximately $2,000,000 in capital funds. 2. Approximataly $4,000,000 for dasign, anginaaring and experimental work. 3. Raduction in plant capacity from 2,000 tons par yaar to 750 tons par yaar. 4. Raduction in amployaas from 300 to lass than 80. Ona of tha major staps that anablad us to ganarally raduca TWA airboma concantrations of asbastos to 2 f/cc, was tha adop tion of "damp* manufacturing techniques. Tha product mada by this mathod is eonsidarad infarior to tha dry proeass aatarial for many usas. Tharafora, Johns-Manville dacidad to produca only thosa taxtilas which wa would convart, "in-housa", in latar manufacturing stagas, into gaskats and machanical packings. This decision resulted in tha drastic reduction in production capa bility and number of amployaas. In davaloping our dasip processing method wa mada tha following major operating changes: 1. Fibar blending a. Eliminated tha operation. 2. Carding a. Rebuilt tha carding"machinery to permit direct introduction of asbastos fibar and precise blending of tha asbastos with a formed lap carrier yam. b.Installed a system for recovering all extraneous waste asbestos fibers and routing them back into tha carding system. c.Provided for the insertion of an organic or inorganic reinforcing strand at tha card condenser. d.Installed equipment to apply an aqueous wetting agent to the formed roving. a.Modified tha card to wind an enlarged roving package. (39) DUP 1152531 DU 061846 <?'<2-0 3. Spinning a. Eliminated the operation. 4. Twisting a. Developed a method for twisting multiple strands of carded roving with reinforcing inserts. b. Installed equipment to apply a lubricant and a dust suppressant wetting agent to the yam. 5. Weaving a. Revised the weaving operation to include direct appli cation of dust suppressant wetting agents to the warp and fill yams. 6. General a. Greatly enlarged operating area per machine Despite this major program to improve working conditions in our textile operation, we have achieved the proposed 0.5 f/cc exposure limit at only 551 of our work stations. The present status is: Ho. of Work Stations Monitored Less than 0.5 Fiber Levels . 0.S-2.0 2.0-5.0 Greater than 49 27 21 1 0 We believe that our Manville textile operation is the most technologically advanced (insofar as control of worker exposure is concerned) operation in existence today in the United States. The only modification known'to us would be the adoption of the wet, or liquid dispersion, process for yam formation. However, this would not significantly improve conditions at the "downstream" operations. At this point in time, we do not know what technology - at what cost, or what implementation time - could be developed that would enable the asbestos textile industry to Met a Permissible Exposure Limit of 0.5 f/cc. (40 DUP J 152532 DU 061847 BUILDING SYSTEMS Basic Description Asbestos-Cement Sheet - This product is durable, flexible fire-resistant panel used in many industrial and commercial building applications. Zt is frequently laminated to different core materials and used as sound deadening, fire resistive interior partitions. Raw materials utilized are asbestos fiber, Portland cement and sand. ACE - The ACS product line includes formed- and cored asbestoscement panels and shapes manufactured by an extrusion process. Their prime use is an non-load bearing exterior wall panels in commercial and industrial building construction. Raw materials utilized are asbestos fiber, Portland cement and sand. Process Description Asbestos-Cement Sheet - Bags of asbestos fiber are transported on pallets to the bag opening station. Bare bags are manually opened, dumped and disposed under a dust control hood. After fiberizing, the fiber is conveyed to a dry mixer where it is combined with the other raw materials. The raw material mix proceeds to a wet mixer and then to the cylinder type forming machine. After forming, the sheets are stacked between caul plates and transported to a hydraulic press for "repressing." The next process steps are air cure and steam cure (autoclaving). The final step in the sheet production process is trimming to size by semi-automatic trim saws. The current range of airborne concentrations of asbestos fibers to which our employees are exposed, without regard to the use of respirators, in each process step in our asbestos-cement sheet manufacturing facilities, are set forth in Figure 6. The two problem areas in this operation have been reviewed in other asbestos-cement product segments; they are: 1. Fiber introduction a. Bag opening, emptying and disposal b. Fiber handling (41) DUP 1152533 DU 061848 jm If iTiiafliiiiil iiiiiiiiaoMiMi C- 2. Product finishing a. Sawing (trimming) The TWA exposures at the fiber introduction operation range from 0.5 to 2.2 /cc, with an average of 1.2 f/cc. Further reduct of airborne concentrations of asbestos fibers will require similar undertakings to those described for the asbestos-cement board operation. Employee exposure levels at the trim saw range from 0.8 to 4.1 f/cc, with an average of 1.9 f/cc. Further reductions of airborne concentrations of asbestos fibers will require: 1. Development of improved mechanical exhaust ventilation systems for the trim saws. ACE - The ACE production operation is the newest of our asbestosusing manufacturing facilities. It incorporates our latest de sign _ of bag opening station, a new wet mixing system, and a highly sophisticated and automated saw line and surface finishing line. As in other asbestos-cement operations, bagged asbestos fiber i transported on pallets to the bag opening station. Bags are opened, emptied and disposed under a dust control hood. After the opening process, fiber and the other raw materials are combine in a wet mixer. The combined raw materials are conveyed in "pug" fora to the extruder. After extrusion the panels are air cured and steam cured. The cured panels are conveyed through the saw line where they are cut to length and the finishing line where a surface texture is applied. The current range of airborne concentrations of asbestos fibers to which our employees are exposed, without regard to the use of respirators, in each process step in our ACE manufacturing facil ities, are set forth in Figure 7. The only process step in this production operation which gen erates significant concentrations of asbestos fiber is the bag opening station. Exposure levels at this process step range from less than C.5 o 2.2 f/cc, with an average of 1.1 f/cc. Again, our proposal for reduction in exposure levels is the installation of an automated bag opening system. (42) DUP H52534 DU 061849 / f X i3 19 *-Il-| <n in in u<zl Q. uJ * 0 2 Z s<r 1/3 X ui hh <S <ny >ui OJ S* OC D v9 z 5 j a \ < 5 mO (E 2 oJ yJ aa d1 PROCESS STEPS NV"ld `3NO Nf 32NV\d V/v\x -33 Ad DU 061850 nilP 1 152535 I- u PROCESS STEPS in Z UJ hr* ifi u > Jl uf Hi CL ZJ oa LL _j Si (Si - 'i -n Ti i r in ^ c*) i\i -LfWId 3NC? N1 3V NV'd VM1 - JD/1 0 DU 061851 DUP 1152536 PAPER Basic Description Asbestos-containing papers have a variety of uses. The coarsa papers, often referred to as "felts," are asphalt saturated and are used in "built-up" roofing systems and as pipe line protection wrap. Electrical insulating papers range from commercial grade to the specialty product made from selected, highly refined fibers. These papers are 85% to 95% asbestos combined with a starch, latex or polymeric binder. Process Description Bagged asbestos fiber is transported on pallets to the bag opening station at the beater. The bags are manually opened, emptied and disposed under a dust control hood. The fiber gravity feeds from the opening station directly into the beater. Binder is added at the beater. The fiber and binder are pumped through the stock preparation system to the wet end of the paper machine (Fourdrinier). The paper is formed and then conveyed through the paper machine dryer section to the wind-up station. Paper is trimmed to width during the winding process. The final step is rewinding of the paper in different size rolls for shipment. ' The specialty electrical papers may undergo further processing including coating, laminating and shearing to length. The current range of airborne concentrations of asbestos fibers to which our employees are exposed, without regard to the use of respirators, in each procesf step in our paper manufacturing facilities, are set forth in Figure 8. The only process step in this production operation which gener ates significant concentrations of asbestos fibers is fiber introduction. Present exposure levels range from less than 0.5 to 2.5 f/cc, with an average exposure of 1.4 f/cc. Reduction of these exposures will require the installation of an automated bag opening system, adapted to feed directly into the paper beater. (45) DUP I 152537 DU 061852 FIGURE 8 PRO CE.SS S T E P S Ql iad d CL S'JJNVld tjnad Nt STNVy V/^l 33/J DU 061853 DUP 1152538