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Environmental/Industrial Hygiene Surveys of Vinyl Chloride Monomer Manufacturing Operations and Operations Where Polyvinyl Chloride and Copolymers of Polyvinyl Chloride are Processed / Bendix Corp. / Cocoa Beach, FL ;Ii i I I Prepared for National Inst, for Occupational Safety and Health, Cincinnati, OH Aug 75 PB62-109y75 U.S. Department of Commerce Kitsofiai Technical Information Service mama ] CMA 005193 i/ PRR2-I0O076 / ENVIRONMENTAL/INDUSTRIAL HYGIENE SURVEYS OF VINYL CHLORIDE MONOMER MANUFACTURING OPERATIONS AND OPERATIONS WHERE POLYVINYL CHLORIDE AND COPOLYMERS OF POLYVINYL CHLORIDE ARE PROCESSED W. L. Barnhart C. R. Toney J. B. Devlin The Bendix Corporation Launch Support Division Cocoa Beach, Florida Contract No. CDC-99-74-50 U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Center for Disease Control National Institute for Occupational Safety and Health August 1975 araftvcto iv NATIONAL TECHNICAL INFORMATION SERVICE (I*. MPAmiKNi of cctfmict WMfGWIO, U 2141 CMA 005194 A The contents of this report are reproduced herein as received from the contractor. The opinions, findings, and conclusions expressed are those of the contractor and not necessarily those of NIOSH Mention of company or product names is not to be considered as an endorsement by NIOSH. - >Wl i RCPORr DOCUMENTATION PACE TUS-49.5 * NA 4. Till* .n* b.inlt Environmental/Industrial Hygiene Surveys of VJntl Chloride Monomer Manufacturing Operations and Operations Where Polyvinyl Chloride and Copolvroers of Polyvinyl Chloride are Processed 7* AulKodt) Barnhart, W.L., C.R. Toney, and J.B. Devlin 1, PriQrm|i\| Orfnlisbort Hmm* and Adtffm The Bendix Corporation, Launch Support Division, Cocoa Beach, Florida 12* Sppntvrinf OfC*nlx*t*n Nom *4 A4d*ct r r~ -..." ......... IS. SMpp4mtt|afy Nt NA 2. ACcttHM na Pit? 10 9 9 7 A s, d*i August, 1975 U273015 . NA 10. Projotf/Totb/Werk Unit No. NA 11. CtMnnQ H Ci.nKO N*. CDC-99-74-50 to 1L Tjrp* of Rpon 4 F*roO Csvtrtd Contract Report llL A^tinct i ; j ; ; ; '\ 200 Worker exposures to vinyl-chloride (75014) (VC) were surveyed at three VC manufacturing and seven polyvinyl-chloride (TVC) processing facilities (SIC-2821). Breathing zone and area air samples were taken in various areas within each facility, and were analyzed by flame ionization gas chromatography. VC concentrations in the three manufacturing companies ranged ^ro 0*01 to 5.89, 0.01 to 84.77, and 0.02 to 21,8 parts per million (ppm), respectively. Personal exposures in excess of the l.Oppm standard occurred for the laboratory technicians, operators and loaders at two manufacturing facilities, and for the loaders, operators, chromatography operators, and shift supervisors at the third facility. No detectable VC concentrations were found at six of the seven PVC facilities. At the seventh facility, VC concentrations ranged from 0.02 to 2.44ppm. The blender operators, driver-- baggers, and banbury operators were exposed to excessive VC concentrations, pie authors conclude that excessive VC exposure exists at several of the facilities surveyed. They reconmend use of respirators and protective clothing, installation of devices to detect excessive VC concentrations in the work areas and use of positive air pressure in laboratories and eating and smoking rooms. 17* Dotvmtfll AntlftU a. 0riptOn * ( : j. i ; . # Field-Study, Synthetic-resins, Region-4, Health-surveys, Work-environment, Air--contaminants, Chemical--exposure, Industrial-processes, Occupations1-health-programs, Standards [k Ttnni c_ COSATI flal./Cnup^ It, AvaMablUlf Available to the Public 'N5UUt.ll) 19* l#cv'r Clnt ftM* Arport) NA TO. Security Clait flhU fl* No. of N|t 110. **. eat. (Umtily U'l 3j.' \ CMA 005196 CONTENTS Paragraph, Varmary Introduction ' General Remarks Description of Vinyl Chloride ManufacturingProcesses Acetylene-Hydrogen Chloride Process Ethylene Dichloride Pyrolysis Process Oxyhydrochlorination Process Description of Polyvinyl Chloride ManufacturingProcesses Compounding Extrusion Molding Calendering Thermoforming Bonding of Polyvinyl Chloride Foams Fibers Plastisols ' Description of Vinyl Chloride Monomer PlantsSurveyed Plant A Plant B Plant C Description of Polyvinyl Chloride ProcessingPlantsSurveyed Plant D Plant E Plant F ill fa9e ^ 9 10 11 11 13 15 18 15 15 15 19 20 20 21 22 22 23 23 27 32 44 44 47 50 CMA 005197 CONTENTS (continued) Paragraph Page Description of Polyvinyl Chloride Processing Plants Surveyed (continued) Plant G 53 Plant H 56 Plant 1 60 Plant J 64 Job Description for PolyvinylChloride Processing Personnel 69 Sampling Procedure 76 Sampling Results 78 Vinyl Chloride Concentration Data 80 Plant A 80 Plant B 82 PI ant C 85 Plant D 89 Plant E 91 Plant F 93 Plant G Plant H 95 97 Plant I 98 Plant J 100 Analysis of Data 101 Plant A 101 Plant 8 103 Plant C 104 Plants D, E, F, G, H, I, andJ 107 Conclusions 109 iv CMA 005198 FIGURES Fiqure 1 2 3 4 i 5 1' 6! 7; 8 9 10 n 12 13 14 Acetylene-Hydrogen Chloride Process Ethylene 01 chloride Pyrolysis Process Oxyhydrochlorination Process Flow Schematic, Plant A Flow Schematic, Plant 0 Flow Schematic, Plant C Flow Schematic, Plant D Flow Schematic, Plant E Flow Schematic, Plant F - -- -................... Flow Schematic, Plant G Flow Schematic, Plant H Flow Schematic, Plant I Flow Schematic, Cast Film Production, Plant 0 Flow Schematic, Calendered Film Production, Plant 0 ESSe 12 14 17 24 28 33 46 49 52 55 59 63 67 68 Table 1 2 3 `1 TABLES "' '1 1 ! Polyvinyl Chloride Processing Company Preliminary Survey List Vinyl Chloride Concentration Range for Plants A, 8, and C Vinyl Chloride Concentration Range for Plants D, E, F, G, H, I, and J in PPM Page 2 43 75 V /. --' ChA 00519? SUMMARY An in-depth survey of three vinyl chloride manufacturing and seven polyvinyl chloride processing plants was performed by the Bendix Launch Sup port Division Special Projects Group using the procedures set forth In the KIOSH Vinyl Chloride report, P&CAM #127^ to determine the quantity of vinyl chloride existing in the breathing zone of each employee tested in the sur veys. Area samples were also collected in a number of locations. All of the samples were analyzed using a dual-column flams ionization gas chromatograph with chart-type recorder. Personal air sampling pumps set to operate at a flow rate of 50 milliliters per minute were used to collect all of the charcoal samples. The companies selected for the in-depth surveys were chosen on the basis of a preliminary survey of six vinyl chloride manufacturing companies . and 12 polyvinyl chloride processing companies. (See Table 1, Polyvinyl Chlo ride Processing Company Preliminary Survey List following.) In the preliminary survey, 10-second air samples wej-e collected in a variety of work areas. The Information used in selecting the three vinyl chloride manufacturing plants for the in-depth surveys were: A general description of the vinyl chloride monomer processing operations. Eight-hour daily time-weighted average exposures (TWA's) of vinyl chloride for each different job type/job operation in the monomer processing area. Including a specific job description for each of the job types. ^Organic Solvents In Air. National Institute for Occupational Safety and Health. P&CAM 127. May 1974. 11 p. 1 i CMA 005200 TABLE 1 POLYVINYL CHLORIDE PROCESSING COMPANY PRELIMINARY SURVEY LIST Bonding Calendering Compounding Extruding j Fibers Foams Molding P la s tis o ls Thermoforming Company 1. XX 2. 3. (Plant E) 4. XX X XX XXXX X X 5. XX X 6. (Plant IJ XX X 7. (Plant J) XXXX XX XX 8. (Plant F) X X X 9. 10. (Plant H) 11. 12. (Plant D) 13. (Plant G)* Total XXX XXXX XX ( X XX XX X XXX X XX XX 5 5 12 9 i 3 5 5 4 This plant was selected for the in-depth survey after the preliminary survey was completed. / CMA 005201  General area (stationary) samples of vinyl chloride in areas of suspected high concentrations. Raw material and product lists and quantities thereof that relate to the past and present vinyl chloride levels. Ventilation design and ventilation measurements. Including docu mentation of dates of ventilation changes and the extent of changes and how they relate to past and present vinyl chloride levels. I! llork practices that have been instituted to lower vinyl chloride I levels. I Photographs, sketches, etc. to document existing conditions. Documentation of past and present industrial hygiene practices. Including utilization of protective clothing (i.e., type, frequency of change, laundering practices, etc.); protective devices (i.e., respirator-usage, frequency type, etc.); housekeeping practices; shower requirements; eating, smoking, and drinking practices in production areas, etc. The Information used in selecting the polyvinyl chloride plants for the In-depth surveys were: A survey of the following operations in at least three different plants: compounding, extruding, molding, calendering, thermofonning, bonding, foams, fibers, and plastisol processing. Information gained from preliminary site visits. Information gained from literature searches. Information gained from personal contacts. Representativeness of the operations to Industry-wide processing. Operations having the greatest potential for worker exposures to vinyl chloride. v. 3 CMA 005202  Operations having the greatest gradient of worker exposures to vinyl chloride. Availability of historical inplant air measurements of vinyl chloride The operations having the longest history of polymer processing. A general description of the processes In each plant. t Eight-hour daily TVA's of vinyl chloride for each different job classification. Including a description of eanh job classification. Area samples taken in areas of suspected high concentrations. A raw material and product list that relates to past and present vinyl chloride levels. Ventilation data. Changes made to the ventilation systems. Relation of changes to vinyl chloride levels. Work practices instituted to lower vinyl chloride levels. Photographs, sketches, etc. to document existing conditions. Documentation of past and present industrial hygiene practices, Including utilization of protective clothing (i.e., type, frequency of change, laundering practices, etc.); protective devices (i.e., respirator-usage, frequency type, etc.); housekeeping practices; shower requirements; eating, smoking, and drinking practices in production areas, etc. The results of the surveys indicate that vinyl chloride concentration levels found'in Plant A range from <.01 to 5.89 parts per million (ppm). Job classifications in Plant A where vinyl chloride concentrations above the permissible 0.5 ppm action level and 1 ppm TWA were detected are: Laboratory Technicians (0.4 to 4.36 ppm). Operators (0.13 to 2.45 ppm), and Loaders (0.17 to 1.89 ppm). Area samples ranged from 0.56 to 5.89 ppm. 4 CMA 005203 Laboratory personnel wore cartridge pe respirators during sample handling operations. Loaders wore air line breathing respirators during transfer and loading operations. No tank car loading operations were performed during the survey. All personnel are supplied with respiratory protection devices. Vinyl chloride concentration levels in Plant B ranged from 0.01 to 84,77 ppm. Job classifications in Plant B where vinyl chloride concentra tions above the permissible action level and TWA were detected are: Loaders (3.00 to 84.77 ppm), Operators (0.01 to 3.46 ppm), and Laboratory Technician (.03 to 0.88 ppm). Area samples ranged from 0.09 to 1.22 ppm in the loading area to 0.05 to 0.38 ppm in the manufacturing areas. Laboratory personnel wore cartridge-type respirators during sample handling operations. Loaders wore air line breathing respirators during transfer and loading operations. No loading operations were performed during the survey. All personnel are supplied with respiratory protection devices. Vinyl chloride concentration levels in Plant C ranged from 0.02 to 21.8 ppm. Job classifications in Plant C where vinyl chloride concentrations above the permissible action level and TWA were detected are: Loaders (0.06 to 21.8 ppm). Operators (0.08 to 18.2 ppm), Gas Chromatograph Operators (0.02 to 1.01 ppm), and Shift Supervisors (0.25 to 0.55 ppm). Area samples `/ ranged from 0.59 to 7.06 ppm In the manufacturing areas. Laboratory person nel wore cartridge-type respirators during sample hanoling operations. Leaders wore air line breathing respirators during transfer and loading operations. Tank car loadings wer* >erformed during the survey. All person nel are supplied with respiratory protection devices. Hose line respirators were worn by the operators during the time they were exposed to the higherthan-permissible concentrations of vinyl chloride. CMA 005204 *\ . / ! \/ 1\< v- No vinyl chloride concentration levels above the permissible action level were detected in polyvinyl chloride processing plants D, E, F, G, H, and J. The only polyvinyl chloride processing plant where vinyl chloride levels were above the permissible action level end TWA was Plant I where levels ranging from 0,02 to 2.44 ppm were detected. Job classifications In Plant I where levels above the permissible action levels were detected are: Blender Operators (0.46 to 0.69 ppm), Banbury Operators (0.37 to 0.60 ppm), anJ a Driver-Bagger (0.02 to 0.76 ppm). Levels above the permissible TWA were detected on one day of the survey and ranged from 0.13 to 2.44 ppm. Plant I is the only plant contacted during the survey that has an on site polyvinyl chloride resin plant. It has two on-site resin plants which undoubtedly account for the high vinyl chloride concentration levels that appear in the survey analysis data. On the day that levels above the per missible TWA were detected, a rupture disc failed in one of the resin plant reactors. This allowed vinyl chloride fumes to vent to the atmosphere and the fumes were pulled into the adjacent processing plant via the ventilation system. Respirator devices are available for personnel working in the polyvinyl chloride processing plants; however, due to the low levels of vinyl chloride normally found in these plants, they are seldom, used. Dust-type respirators are worn during dusty compound preparation operations. Eating In the vinyl chloride and polyvinyl chloride manufacturing plants Is restricted to enclosed, air-conditioned rooms. Smoking is allowed In specified areas or in enclosed air-conditioned rooms. .. The following conclusions were reached during the in-depth surveys per formed at three vinyl chloride manufacturing plants and seven polyvinyl chloride processing plants. 6 CMA 005205  Despite sincere efforts on the part of all companies contacted to reduce the level of vinyl chloride to which their employees are exposed, vinyl chloride concentrations above the OSHA-prescribed 1-ppm TWA and 5-pptn, 15-minute ceiling still exist In some vinyl chloride manufacturing, storage, and loading areas. Loading personnel must wear respirators and protective clothing designed to handle the high concentrations of vinyl chloride that occur during vinyl chloride transfer and loading operations. Instruments that detect the presence of vinyl chloride in the work areas are necessary to prevent personnel from being unaware of ex posure to vinyl chloride. All personnel working in vinyl chloride plants must be supplied with and trained in the use of respirator devices that are designed to handle the concentrations of vinyl chloride that can occur In the work area. Personnel handling vinyl chloride should wear gloves and disposable or washable outer garments In addition to a suitable respirator. t All of the vinyl chloride manufacturing plants contacted for the vinyl chloride survey produced vinyl chloride in outdoor facilities. The enclosed control rooms, laboratories, and eating and smoking i rooms should be maintained under positive pressure with the air free from chemical contaminants to prevent these areas from being contaminated by outside air. t There have been many recent changes made in equipment seals and designs. Improved ventilation, revised operating procedures, and Improved industrial hygiene and safety practices. These changes A 7 CMA 005206 for Improvement, plus the use of closed-loop sampling and loading systems have had and will continue to have considerable effect in reducing the concentration of vinyl chloride in vinyl chloride manufacturing plants. See Description of Vinyl Chloride Monomer Plants Surveyed (Plants A, B, and C). / j The reduction of entrained vinyl chloride in the polyvinyl chloride I resins and compounds used by the polyvinyl chloride processing in/ dustry has reduced the exposure of the workers in this industry i below the OSHA-prescribed action level of 0.5 ppm. ,,/ \ 8 CMA 005207 INTRODUCTION Information that has been made available tc, the National Institute for Occupational Safety and Health (NIOSH) indicates that a serious health problem potentially exists in workers involved with the polymerization of vinyl chloride to polyvinyl chloride. Preliminary mortality information con cerning vinyl chloride polymerization plants has revealed there is a definite excess of deaths due to angiosarcoma of the liver in workers that have been Involved with this processing. Deaths attributed to angiosarcomas of the liver for workers that have been exposed to vinyl chloride either in the manufacture of the monomer, the polymerization of the monomer into polyvinyl chloride, or the processing of the polymerized vinyl chloride into polyvinyl chloride products have been reported from Canada, Czechoslovakia, France, Italy, Norway, Rumania, Sweden, West Germany, and the United States. Based on the above, vinyl chloride has been shown to be an etiologic agent in the deaths of the above-mentioned workers. Due to the large work force involved in the manufacture of vinyl chlo ride, polyvinyl chloride resins and compounds, and the conversion of the resins and/or compounds into finished goods, NIOSH immediately initiated an extensive epidemiological investigation (including environmental surveys} into operations and the workers involved in them where the exposure to vinyl chloride and polyvinyl chloride is known to exist. The purpose of this contract was to document past and present worker exposures to vinyl chloride during (1) the monomer production and (2) the processing of polyvinyl chloride and polyvinyl chloride copolymers. In addition to documenting worker exposures to vinyl chloride. Information on 9 CMA 005208 work practices, envJronmental control procedures, and industrial hygiene practices was also documented. These data will be utilized to ascertain the extent of worker exposures to vinyl chloride and possibly other liver toxins so that the possible health effects impact in the industry can be determined, and appropriate priorities for corrective measures can be set. GENERAL REMARKS During the time period that the in-depth survey of the vinyl chloride manufacturing companies and the polyvinyl chloride processing companies was performed, the plastics industry, and large segments of other industries in the United States, were in an economic slump. In general, the companies surveyed were operating at 20 to 50 percent of their normal production rate. For this reason, the concentrations of vinyl chloride detected in the various locations sampled durina the survey may well have been lower than normal. Also, a considerably lower number of employees were available to take part in the sampling program. 10 i J. CMA 005209 DESCRIPTION OF VINYL CHLORIDE MANUFACTURING PROCESSES At the present time, vinyl chloride is manufactured in the United States using three basic processes: (1) acetylene-hydrogen chloride process, (2) oxyhydrochlorlnation process, and (.1) ethylene dichloride pyrolysis process. Acetylene-Hydrogen Chloride Process Dry acetylene and anhydrous hydrogen chloride are reacted in fixed-bed reactors containing mercuric-chloride-impregnated carbon catalyst. The re action products are compressed, cooled, and passed to a refrigeration unit for separation of vinyl chloride by condensation. The condensed vinyl chloride is then passed to a two-column purification train. Low-boiling products are removed overhead In the first column and recycled to the fixedbed reactor along with noncondensed vapors from the first column feed drum. A portion of the recycle is passed to a vent reactor where additional reac tion occurs. The vent reactor products are returned to the distillation train; the inerts are vented to the atmosphere. The partially purified vinyl chloride is passed to the second column where the high-boiling compounds are removed and passed to an incinerator for disposal. The purified vinyl chloride removed from the second column is first transferred to holding tanks where purity is checked, and then to storage spheres. Tank cars are loaded with vinyl chloride from the storage spheres for shipment to vinyl chloride polymerization plants. A flow schematic of this process is shown In Figure 1. 11 CMA 005210 /- CMA 0 0 Legend: A - Reactor B - Compressor & Cooler C - Fractionation Train D - Vinyl Chloride Storage Tank E - Heavy Ends Storage Tank F - Vent Reactor G - Pumps H - Tank Cars I - Incinerator J - Atmosphere 1 - Hydrogen Chloride c.n w 2 - Acetylene 3 - Vinyl Chloride Figure 1. Acetylene-Hydrogen Chloride Process Ethylene Dichloride Pyrolysis Process C2H4 + Cl ---------- C1CH2CH2C1---------- > cich2ch2ci CH2CHC1 + HC1 Wet ethylene dichloride produced by the direct chlorination of ethylene is passed through a drying column for removal of water, combined with recycle ethylene dichloride, and sent through a purification train for removal of heavy ends. The purified ethylene dichloride is vaporized in a vaporizer and fed into a cracking furnace. The reactants from the cracking furnace are cooled and partially condensed in a quench system. The condensate is fed to an ethylene dichloride recovery column where ethylene dichloride is removed from the bottom of the column, passed to a light ends column for removal of light ends, and recycled to the purification train. Overhead vapors from the ethylene dichloride recovery column are combined with quench system vapors, compressed, and fed to a hydrogen chloride recovery column. Pure hydrogen chloride is removed overhead, transferred to other on-site plants, and used in other processes. The bottoms from the hydrogen chloride recovery column Is passed to a fractionating column where purified vinyl chloride is removed overhead and sent to storage spheres. A flow schematic for this process Is shown in Figure 2. / 1 13 DMA 005212 / \' -/ '2i TP _r* A Vv X Legend: A - Drying Column 8 - Heavies Column C - Cracking Furnace D - Quench Unit -------------E - Fractionation Column F - Hydrogen Chloride Recovery Column G - Compressor H - Light Ends Column I - Ethylene Dichloride Recovery Column &] 1 - Wet Ethylene D'chloride 2 - Water 3 - Lights 4 - Heavies 5 - Hydrogen Chloride 6 - Vinyl Chloride I IT t \ CMA 0 0 5 2 1 3 Figure 2. Ethylene Dichloride Pyrolysis Process I Oxvhvdrochlorination Process C2H4 + CI2 * C7 CHgCiHgC 7 C1CH2CH2C1 ----------- * CH2CHC1 + HC1 C2H4 + 2HC1 + 1/2 02 ------------ C1CH2CH2C1 Ethylene dichloride produced fay reacting chlorine and ethylene is pyrolyzed to form vinyl chloride and hydrogen chloride. The hydrogen chloride is sepa rated from the reaction products and reacted with ethylene and air (oxygen) to produce ethylene dichtoridc and water. The ethylene dichloride produced by this reaction is dried and pyrolyzed to form vinyi chloride and hydrogen chloride. Ethylene and chlorine are reacted In a water-cooled direct chlorination reactor to produce crude ethylene dichloride. The crude ethylene dichloride is sent through an ethylene dichloride purification train where light ends are removed overhead in the first column and heavy ends from the bottom of the second column. Purified ethylene dichloride removed overhead from the second column is sent through an ethylene dichloride cracking furnace. The reaction products from the cracking furnace are passed to a hydro gen chloride column where crude vinyl chloride is removed as bottoms and sent to a vinyl chloride purification column. Pure vinyl chloride is recovered from the top of the vinyl chloride column and transferred to a storage area where it Is stored in large spheres. The bottoms from the vinyl chloride column are recycled to the ethylene dichloride purification train. Pure hydrogen chloride coproduct from the top of the hydrogen chloride column Is sent to the oxyhydrcchlor*nation reactor where it is reacted with ethylene and air to produce ethylene dichloride and water. The reaction products are sent through an oxyhydrochlorination primary recovery unit where 15 CMA 005214 the water is removed as bottoms and sent to waste. The overheads are passed to a second column where crude ethylene dichloride is removed as bottoms and cycled to the ethylene dichloride purification train. The overheads are passed to a secondary oxyhydrochlorination recovery unit. Vent gas is re moved overhead in the first column, and the bottoms are sent to a second column. The overheads from the second column are recycled to the second column of the oxyhydrochlorination primary recovery unit. Pure vinyl chloride is transferred to tank cars for shipment to vinyl chloride poly merization plants. A flow schematic for this process is shown in Figure 3. 1 16 Z CMA 005215 Legend: A - OHCL Reactor B - OHCL Primary Recovery C - OHCL Secondary Recovery D - Direct Chlorination Reactor E - EDC Purification F - EOC Cracking Furnace 6 - HCL Column H - VCL Column 1 - Air 2 - Ethylene 3 - Chlorine 4 - Waste Water 5 - Crude EDC 6 - Vent Gas 7 - Lights 8 - Heavies 9 - Recycle EDC 10 - Vinvl Chloride Figure 3. Oxyhydrochlorination Process f DESCRIPTION OF POLYVINYL CHLORIDE MANUFACTURING PROCESSES Compounding Compounding is the mixing of polyvinyl chloride resin with other materials, i.e., plasticizers, stabilizers, pigments, toners,fillers, lubricants, blowing agents, anti-oxidants, fungicides, santicizers, and modifiers to manufacture specific polyvinyl chloride products. Compounding is generally accomplished in blenders, Banbury's, two-roll mills, and mixers. Combinations of the above equipment can be employed in a single compounding operation. Blenders are primarily used to make dry com pounds. Mixers are normally used to make fluid-type compounds such as plastisols. Compounds containing solids are masticated using Banbury's, mixers, or two-roll mills. Extrusion Extrusion can be used to remove solids from plastic-type compounds, to deaerate and compact compound, and to generate sufficient pressure to force the material through an extrusion die. The extrusion can be in the form of a rope that is fed to a calender, or a long length of material having a uniform cross section. Examples of extruded items are hoses, pipes, rods, threads, pellets, and shapes of intricate cross section. Extrusions can be rigid or flexible. Molding Molding can be divided into a number of types, I.e., injection molding, blow molding, vacu-formlng, and embossing. The equipment used for each type of molding is entirely different In design and operation. Injection molding Is accomplished by forcing a plastic or fluid-like compound into the cavity of a heated mold. The end product assumes the con figuration of the mold cavity and can be solid, hollow, rigid, or flexible. 18 CMA 005217 Blow molding begins with the injection of a predetermined amount of plastic compound into the cavity of a mold. Air is then injected into the center of the injection and expands the plastic compound until it reaches the wall of the cavity. Sufficient air pressure is used to m-.ke the in jected compound assume the configuration of the mold. The mold is heated and sets the design of the molded item. Blow-molded products can be rigid, semi-rigid, or flexible. Examples are plastic containers, wheels for toys, and basketballs. Vacu-formlng is accomplished by laying a sheet of preheated film on top of a mold. The air between the film and the mold is removed by a vacuum pump, and the atmospheric pressure above the sheet forces the hot film against the mold. The cold mold sets the mold design in the film. Vacuum-formed items can be semi-rigid or flexible. Embossing is the imprinting of a design into a sheet of plastic and is normally accomplished by feeding a plastic sheet through a set of rolls. One of the rolls contains the configuration that is to be imprinted into the plastic sheet. The other roll provides the pressure required to form the design in the plastic sheet. An example of embossing is the imprinting of a leather grain into plastic sheet stock. Calendering Calendering is generally accomplished using three- or four-roll calenders. The calender most often used in the plastics industry is the' four-roll "Fu form calender. This type of calender has a stack of three rolls In a vertical plane and two top rolls in a horizontal plane. In using this type of calender, a ribbon, cord, or belt of fluxed plastic is fed evenly across the "V" between the two top rolls of the calender to permit gravity feed of the stock to the calender. An adjustable gap between the calender tolls produces a continuous 19 CMA 005218 sheet of plastic having uniform thickness and longitudinal physical properties across the width of the sheet. The calender rolls also impart a smooth finish to both sides of the sheet as it passes through the rolls. A smallerdiameter roll strips the sheet of plastic from the last calender roll and passes the sheet through a series of tensioning and cooling rolls. The cooled sheet is edge-trimmed and then fed to the windup rolls where the sheet is wound under uniform tension into rolls of desired diameter. Thermoformino Thermoforming is the forming of various shapes in thermoplastic sheets through the application of heat and pressure, and employs molds or forming blocks to shape the plastic. Seven basic types of thermoforming are recognized by the plastics industry. Each type uses various modifications of the molds, forming blocks, clamping devices, frames, and pressures to form the desired end product. The seven types are: straight vacuum forming, drape vacuum forming, male form forced above sheet, vacuum snap-back forming, plug and ring forming, air pressure forming, and matched metal mold forming. Thermoformed \ . products are finding usage in the packaging, automotive, furniture, toy, and garment industries. Bonding of Polyvinyl Chloride Bonding is the joining of two or more pieces of polyvinyl chloride through the use of adhesives, or the application of heat with or without pressure. Thermoplastic sheets and films can be joined by heat sealing. Rigid thermo plastic materials such as laminate sheet, rod, and tubing can be joined by \ adhesives or by hot gas welding. Polyvinyl chloride adhesives contain solvents such as tetrahydrofuran to produce tight, quick, and rapid assembly of components. Heat sealing can be , _/ \\ / 20 11 ChA 005219 accomplished through the use of one or two metal items containing electrical heating elements, oven heat, or high-frequency or electronic heating. Hot gas welding employs a gas or electrically heated gun and polyvinyl chloride weld ing rod to join the materials. This type of weld is similar in appearance to metal welds. Foams Polyvinyl chloride foam formulations have a fluid or semifluid consis tency and contain a blowing agent that produces a cellular structure in the finished item. In the case of sheet material, the formulation is spread onto paper or fabric and then passed through one or two ovens to expand and cure the sheeting. Normally,where paper is used as a backing material, the paper backing is stripped from the foamed sheet after leaving the first tunnel type nven. The foamed sheet can than be joined to a second sheet to make a sandwich-type sheet stock that is sealed and final-cured in a second tunnel oven. Multi-layer sheet stock can be manufactured by joining a foam-coated fabric to a second vinyl sheet after the foam-coated fabric leaves the first tunnel oven. Sealing of the two layers and final curing of the foam com posite takes place in the second tunnel oven. Heated molds can be dipped into a plastisol formulation containing a blowing agent. A thick coating of the plastisol mixture adheres to and l partially cures on the mold. The coated mold is withdrawn from the dip and Is placed in an oven for the final cure and blowing operation. Now, plastisol-type polyvinyl chloride compounds can be added to rubber-type compounds ana a bowing agent to produce a compound that is processed on a Banbury and a two-roll mill. The milled stock can be further processed in a tube-type extruder. The extruded stock can be cut Into desired shapes and expanded and cured in a series of two ovens, or the tubular stock can be expanded and cured in a tunnel-type oven. 21 a - CMA 005220 Fibers Polyvinyl chloride compounds can be extruded through a die containing a number of sma'l round or rectangular openings to produce a round or-rectangular cross-section thread. The thread is passed through a cold water bath, dried, and wound onto spools. Fibers or webs of fibers can be pressed into or layered onto a sheet of hot polyvinyl chloride in a calender to produce a sheet stock containing fibers or a web of fibers imbedded in the sheet. Poly vinyl chloride sheeting prepared in this manner has superior strength and resists tearing and stretching. i I Plastisols Plastisol formulations are of fluid or semifluid composition. Preheated molds are dipped into the mixture, causing a thick layer to coat and partially cure on the mold. The mold is then withdrawn and placed in an oven for final cure of the compound. After oven curing, the plastisol-coated mold is removed from the oven, and the formed item is stripped from the mold using air pressure. The mold is then dipped in or sprayed with a release agent and returned to the preheat oven. The operation can be performed by hand or by automated units. Plastisol coatings can also be applied to a fabric in a uniform layer and then passed through an1 oven where the coated stock undergoes partial curing. The coated stock is final-cured in a hot platen press. The platens can be plain or configured, and any design on the platen will be reproduced in reverse on the surface of the finished stock. 22 ,/ CMA 005221 DESCRIPTION OF VINYL CHLORIDE MONOMER PLANTS SURVEYED Plant A This facility manufactures vinyl chloride using the Acetylene-Hydrogen Chloride Process portrayed in Figure 4. The plant normally operates at 10 percent of capacity and when acetylene, manufactured at the plant, is avail able for the manufacture of vinyl chloride. Nearly all of the acetylene manufactured at this site is sold as product to nearby chemical plants. The vinyl chloride plant was in operation during the survey. The vinyl chloride plant has been in operation for 12 years and employs 25 people. A total of 375 people are employed at the facility which manu factures acetylene, methanol, ammonia, and vinyl chloride as major products, and vinyl acetylene, diacetylene, methyl acetylene, dimethyl ether, and 2chloropropene as byproducts. Liquid air and liquid nitrogen are also manu factured at the facility. A vinyl chloride surveillance program was established at this company in April 1974. The manufacturing areas are monitored at various points using a Mi ran Infrared Scanner with chart readout, and a Century Organic Vapor Analyzer. Air samples are collected in mylar sampling bags on a regular basis. The air samples are analyzed for vinyl chloride concentration using gas chromatography. The results of the company's sampling program show a hi-lo TWA concen tration range of <.01 to 67 parts per million (ppm) of vinyl chloride. Except for the control laboratory and control room, all operations are performed outdoors. The control laboratory and control room are air condi tioned with one air change per minute. 23 i I l/ CHA 005222 / _/l___ _ \ Legend: . A - Reactor B - Compressor S Cooler C - Fractionation Train D - Vinyl Chloride Storage Tank E - Heavy Ends Storage Tank F - Vent Reactor G - Pumps H - Tank Cars 1 - Incinerator J - Atmosphere 1 - Hydrogen Chloride 2 - Acetylene 3 - Vinyl Chloride Figure 4. Flow Schematic, Plant A CMA 0 0 5 2 2 3 The following changes have been made to their industrial hygiene program. All employees are required to wear air-supplied respirators when vinyl chloride monomer is expected to be over 50 ppm. Signs are posted whenever area monitoring indicates high vinyl chloride monomer is in the air. Additional purging time is required on all vessels which handle vinyl chloride monomer prior to being opened. High' priority has been placed on work designed to eliminate vinyl chlo ride monomer leaks. Gas masks and slicker suits are worn in accordance with current OSHA regulations. Job descriptions for employees who potentially come into contact with vinyl chloride monomer are as follows: Operators Operators control the equipment vessels required to produce vinyl chlo ride monomer from acetylene and hydrogen chloride. The equipment operated includes reactors, heat exchangers, pumps, compressors, fractionating towers, and attendant instrumentation. They perform these duties in an open plant or an air-conditioned control room building on a 24-hour-day, 7-day-week manning schedule. They spend approximately 60 percent of their time in the processing area, and 40 percent of their time in the control room area. They oversee the equipment and specify when maintenance is required. They prepare the equipment for maintenance. Shift Supervisors Shift supervisors control the equipment and vessels required to produce vinyl chloride monomer from acetylene and hydrogen chloride. The equipment 25 CMA 005224 operated includes reactors, heat exchangers, pumps, compressors, fractionating towers, and attendant instrumentation. They perform these duties outdoors or in an air-conditioned control room building on a 24-hour-day, 7-dayweek manning schedule. They spend approximately 40 percent of their time in the processing area, and 60 percent of their time in the control room area. They oversee the equipment, and specify when maintenance is required. They prepare the equipment for maintenance, and issue work requests and the neces sary permits. Maintenance Employees assigned to maintenance make necessary repairs to the equip ment found in the vinyl chloride monomer plant. In addition, they do painting and insulating, and change catalyst. When working on equipment which has been in the vinyl chloride monomer service, they are required to obtain appro priate permits from the Shift Supervisor stating that the equipment is safe to work on. Laboratory Technicians Laboratory technicians obtain samples of gases and liquids in the vinyl chloride monomer unit. They perform gas chromatograph and reaction tests on 'these samples either in the unit or in the laboratory. When analyses are made on vinyl chloride monomer, the analyses are made under the hood. Loaders Loaders receive, prepare, load, and sample vinyl chloride monomer tank cars. When handling vinyl chloride monomer, they are required to wear a respirator. 26 CMA 005225 Plant B This facility produces vinyl chloride using the Ethylene Dichloride Pyroly sis Process. The vinyl chloride plant has been operating for 16 years and operates on a continuous basis. Vinyl chloride produced at the plant is sold as a product and is also used on site for the manufacture of polyvinyl chloride resin and 1,1,1-trichloroethane. A total of 2,500 people are employed at the facility; however, only 100 people are involved in the manufacture of vinyl chloride. Other products produced at this facility are tetraethyl lead, tetramethyl lead, sodium, sodium hydroxide, methyl chloride, ethyl chloride, ethylene dichloride, trichloroethylene, and perchloroethylene. The vinyl chloride plant and storage areas are located outside with the exception of the control room, which is air conditioned, and the quality control laboratory. The laboratory is equipped with a supply air blower and exhaust air system via the hoods. The laboratory air is changed every 1.4 minutes. A flow diagram of the process that this company uses to manufacture vinyl chloride is portrayed in Figure 5. A surveillance program for vinyl chloride was put Into effect in April 1974. In this program, a Miran II Infrared Analyzer is used to monitor the plant air for vinyl chloride-in-air on a continuous basis, and portable Century Organic Vapor Analyzers are used for searching out emission sources or wherever "spot" monitoring is desired. The charcoal tube method is used to obtain 15-minute spot samp1.?' and 4-hour personnel samples on a regular basis. Gas chromatography is used to determine the concentration of vinyl chloride picked up in the charcoal tubes. 27 CMA 005226 Figure 5. Flow Schematic, Plant B The results of this company's sampling program show a hi-lo vinyl chlo ride concentration range of <.01 to 62 ppm. The following work practice changes have been instituted to protect their employees. During loading, vinyl chloride monomer tank car spew gauges were pre viously vented to atmosphere. The spew gauge vent system is now closed with a sensing device to detect liquid, indicating the car is loaded. After loading, vinyl chloride monomer tank car load and equalizing lines were previously disconnected with residual vent (mostly vapor) allowed to escape to atmosphere. These lines are now purged with nitrogen (to flare) prior to disconnecting. Vinyl chloride monomer liquid samples were previously taken and disposed of in such a manner that the potential for release of material to the atmos phere was quite high. Closed systems have been provided to permit purging of sample bombs and connections, obtaining of samples, ana disposal of residual sample material without exposure of personnel. The former practice of draining a gage glass to verify the liquid level has been discontinued. Procedures for preparing equipment for opening have been revised, and extra precautions taken to minimize risk of vinyl chloride monomer release to atmosphere. Example: Vinyl chloride monomer liquid product scrubbers were previously prepared for recharging by displacing liquid (with nitrogen) and venting to flare. Purging to remove residual vapors was minimal at best. The revised procedure calls for thorough purging of the scrubber, utilizing heated Inert gas and heating panels on the scrubber shell to ensure negli gible release of vinyl chloride monomer to atmosphere when the scrubber is opened. 29 CMA 005228 While respiratory equipment has always been available for use when needed, personal respirators are now issued to all individuals for use when ever the potential for exposure exists. It is impossible to ascertain the effect of each work practice change separately, but the cumulative effect is favorable as indicated by the re sult of personnel and area monitoring. Changes to their industrial hygiene practices are described below. Prior to the establishment of the 50-ppm interim standard, vinyl chlo ride monomer was considered as one of a family of chlorinated hydrocarbons produced In the Hydrocarbon Area. There were no special hygiene practices in effect for vinyl chloride monomer. Respiratory equipment was available for use in the event of spills or in doing any job where exposure to exces sive amounts of viqyl chloride monomer (other chlorocarbons, hydrogen chlo ride, chlorine) was likely to occur. The situation today, of course, is quite different. Area monitoring for vinyl chloride monomer-in-air is essentially continuous, using a Miran II Infrared Analyzer. Portable de tectors, Century Organic Vapor Analyzers, are used for searching out emis sion sources or wherever "spot" monitoring is desired. Certain areas have been designated as requiring respiratory protection. All personnel have been issued respirators (and trained in their proper use) and have been in structed to wear them when doing any job, c*.g., opening or closing valves, where the potential for exposure to vinyl chloride monomer exists. Supplied air respiratory facilities are being extended to all areas of the vinyl chloride monomer plant. The Medical Department has Instituted a program for routine personnel monitoring utilizing carbon tube adsorption units. A Medical Surveillance 30 i CMA 005229 Program for all personnel who may have been exposed to vinyl chloride monomer In the past has been instituted and will be continued as required by the regu lations persuant thereto. On-the-job eating, drinking, and smoking policies have not been revised as these activities are already restricted to designated areas. This company does not use written job descriptions to outline the respon sibilities of their plant personnel. / I! I '1 s. 31 CMA 005230 Plant C The Oxyhydrochlorination Process is employed by this facility to manu facture vinyl chloride from ethylene and chlorine as illustrated in Figure 6, This company is a large producer of vinyl chloride, normally operates on a continuous basis, and has been producing vinyl chloride at this facility for 12 years. A total of 600 people are employed at this facility; however, only 242 employees are exposed to vinyl chloride. Products produced at this facility are ethylene, chlorine, ethylene dichloride, hydrochloric acid, vinyl chloride, trans-1,2-dichloroethylene, benzene, chloral, carbon tetrachloride, chloroform, trichloroethylene, ethyl chloride, and chlcropropane. No vinyl chloride resin is produced at this site. The manufacture of vinyl chloride is a closed-system operation, and alV of the production equipment is located outdoors except for the instrument houses, control rooms, laboratory, and offices. The offices, laboratory, control rooms, and instrument houses are kept under positive pressure. In addition, the equipment in the instrument houses is purged with nitrogen. No vinyl chloride is piped to the control rooms. All vinyl chloride in the laboratory is kept and handled in hioh-volume venti lation hoods. All production employees have their own respiratory protection devices. Respiratory protection devices are kept in the control rooms for any main tenance personnel working in the area. All personnel have been trained in the use of the equipment and are required to wear respiratory protection equipment when working in areas or performing specific operations where the exposure to vinyl chloride is higher than, or could be higher thon, the permissible OSHA limit. Disposable or washable coveralls are provided for hazardous operations, and gloves are required for personnel performing tasks which col Id 32 CMA 005231 Legend: A - OHCL Reactor 8 - OHCL Primary Recovery C - OHCL Secondary Recovery D - Direct Chlorination Reactor E - EDC Purification F - EDC Cracking Furnace G - HCL Column H - VCL Column 1 - Air 2 - Ethylene 3 - Chlorine 4 - Waste Water 5 - Crude EDC 6 - Vent Gas 7 - Lights 8 - Heavies 9 - Recycle EDC 10 - Vinvl Chloride Figure 6. Flow Schematic, Plant C expose their hands to the chemicals. Shower facilities are provided, and safety showers are available in the vinyl chloride manufacturing areas for emergency use. Smoking and eating are confined to the cafeterias and the control rooms. Good housekeeping is maintained throughout the plant. Loading personnel are required to wear air pressure demand respirators when performing any opera tion where exposure to vinyl chloride is possible. Breathing air facilities are provided throughout the plant. Each instrument house contains an infrared analyzer and gas chromatograph to detect concentrations of vinyl chloride and ethylene dichloride in the production areas. The instrument readout equipment is located in the con trol rooms and is checked out during each shift by the operator. In addition, portable Century Organic Vapor Analyzers are used to check areas where the exposure limits for organic vapors are higher than permissible. A surveillance program for vinyl chloride was initiated in duly 1973, using the charcoal tube method to determine the concentration of vinyl chlo ride that their personnel were exposed to, and the levels existing in the various work areas. In their surveillance program, 50 percent of all per sonnel exposed to vinyl chloride are monitored each week for approximately 10 minutes. The charcoal tube samples are analyzed using gas chromatograp'iy. In addition, all exposed personnel are given medical examinations meeting the requirements specified in OSHA regulation 29 CFR 1910.93q. The following average time-weighted average (TWA) exposures to vinyl chloride have been determined using OSHA pel'sonnel monitoring techniques since August 1974. 34 CMA 005233 Operator Job Classification North and South Furnaces North Purification South Purification North and South Spare East Furnace and Purification East Spare East Synthesis Vinyl Chloride Tank Farm Laboratory Operator Instrument Laboratory Operator Maintenance TWA Average 0.3 ppm 0.7 ppin 0.6 ppm 0.7 ppm 5.2 ppm 1.7 ppm 0.2 ppm 8.5 ppm 0.6 ppm Insufficient Data Insufficient Data Samples were taken while performing activities which gave the greatest proba bility of exposure. Numerous changes have been made to the facility to reduce or eliminate the possible exposure of personnel to vinyl chloride or other su pect agents. A number of these changes are described below. Major equipment changes that have been made to reduce possible exposure to vinyl chloride monomer are: A vinyl chloride monomer vapor collection and recovery system has been installed in the tank farm. Essentially, this consistsof a compressor and ccr.dsrvtinq system. The recovered vinyl chloride monomer is transferred to off-specification storage. A vinyl chloride monomer emergency collection and flare system has been Installed for the process areas. In case of a vinyl chloride monomer release, from a relief valve or vent, the vinyl chloride monomer is piped to a flare. 35 CMA 005234 The caustic scrubbers have the greatest potential for exposing people to vinyl chloride monomer. A vinyl chloride monomer stripper system was installed to remove hydrogen chloride from vinyl chloride monomer and return the hydrogen chloride to the manufacturing unit without exposing people to organic vapors. A system has been installed to supply respirators with breathing air from conveniently located stations throughout the plant. A continuous monitoring system has-been installed in the North ethylene f dichloride unit. By means of a chromatograph, the atmosphere at ten different points in the unit is regularly analyzed for a number of chlorinated organics including vinyl chloride monomer and ethylene dichloride. Additional valves have been put on vinyl chloride monomer tank car loading hoses to almost eliminate exposure due to venting the vinyl chloride monomer vented from the hoses at the end of the loading cycle. The caustic scrubber blowdown has been piped to a blowdown knockout tank which eliminates exposure by venting the vinyl chloride monomer to flare. The North and South hydrogen chlorid* columns have been re-trayed to ex tend periods between opening for cleaning. Changes in operating and maintenance practices and procedures which have reduced possible exposure to vinyl chloride monomer are: Shift monitoring of the plant areas by the operators for hydrocarbons and chlorinated hydrocarbons has been initiated. This is the single most Important change as it gave impetus to the leak detection program and brought the operators and Maintenance full awareness of the vinyl chloride monomer levels in the plant. Elimination of vinyl chloride monomer leaks and escapes was given the number one priority for maintenance and production. 36_________ -/ . _ CMA 005235 Vessel atmospheres for employee entry have been improved. Longer and more effective "boil-outs" are now used and air movers are used to clear residual vapors from vessels requiring personnel entry. The Century Organic Vapor Analyzer (OVA) is also used to determine the level of residual organic vapor in the vessel. Since the OVA is sensitive to any organic vapor, the actual vinyl chloride level would be much lower than the OVA reading. The following guidelines are used for determining the degree of respiratory pro tection required for vessel entry: Organic Vapor Level Respiratory Protection Required Above 50 ppm Between 25 and 50 ppm Air-Fed Respirator Cartridge Mask Below 25 ppm No Protection All vessels are being better prepared for entry and conseque>-*iv they have shown levels no higher than the general atmosphere outside the vessel during personnel entry. It has not been necessary to use respiratory protection for personnel entry. Respiratory protection procedures have been improved. A self-imposed policy of requiring cartridge masks for potential exposures to vinyl chloride in the range of 25 to 50 ppm has been instituted. Above 50 ppm, a continuousflow air-line respirator or self-contained breathing apparatus is used. The plant's respiratory protection program conforms to Federal Register Code 1910.134. The following general guidelines are being used to determine where, when, and what type of respiratory protection is required: Any job which releases vinyl chloride to the atmosphere, and all work done on the domes of the tank cars will require air-line respirators. Any task to be performed downwind or Inside the sphere of contaminated 37 CMA 005236 air of a known vinyl chloride leak will always require an air-line respirator. Cartridge masks will be worn for only those equipment jobs where the vinyl chloride is less than 2 percent by volume of the stream or equipment contents, and where the wind movement is such that an employee can stay upwind and outside of the sphere of contamination by the released gas. Casual observers or supervisors in the vicinity of any of the above operations will be required to wear the same respiratory protection as the person assigned to the job. Air-line respirator usage in the vinyl chloride monomer tank farm has been made more convenient by providing a connection at each of the loading stations. Short hoses are easily moved from station to station. The operators in the areas handling vinyl chloride use the OVA once each shift to monitor designated locations within their areas. Leaks are noted and corrected by the operator where possible. Otherwise the foreman is notified so Maintenance can immediately correct the leak. The Safety Department is using the OVA to thoroughly monitor the pro duction areas at least once a week. Readings are tabulated for each area, and if leaks are noted, they are referred to the area foreman for correction. Most equipment containing vinyl chloride is being depressured to the flare stack, to other equipment, or to remote vents to prevent employee ex posure. The purge lines from the process analyzer instruments have been hooked Lo a conmon header which is exhausted in a remote area that prevents person nel exposure. Vinyl chloride icp"mer in the instrument houses has thus been eliminated. The operator area OVA readings taken each shift quickly detect leaks that have been developed. The process analyzer group then uses the OVA to pinpoint the leak for correction. 38 CMA 005237 The laboratory "wet testing" hood has been updated to give higher volume ventilation and conform to the requirements for handling hazardous materials. Tests have shown no vaKors are escaping from the hood. Collected vinyl chloride monomer samples are no longer permitted to be stored in the process area control rooms. Outside storage is now required. Employees performing tusks where it is possible to contact liquid vinyl chloride monomer are now being required to wear gloves impervious to vinyl j chloride monomer. In shutting down hydrogen chloride and vinyl chloride monomer columns, quench towers, etc., extra steps are taken to strip out the vinyl chloride monomer. When the topping column is down, the overhead of the lights columns is collected by keeping the condensers very cold. In the past, this vapor was vented to the atmosphere. These changes are examples of the greater effort that is made today to ensure that the people in this plant are not exposed to vinyl chloride monomer. These extra efforts by the Company, all of them costly In time or raw materials, have impressed plant personnel, salary and wage, how seriously plant management regards the vinyl chloride monomer problem. Their reaction has been most favorable to the plant's goals of very low exposure. Indeed, this attitude of cooperation and team spirit has been one of the major factors in the suc cess to date. Exposure reduction projects that are in process are: Vinyl chloride monomer process equipment drainage system. t Vinyl chloride monomer tank car gauging system. Vinyl chloride monomer process enclosed sample system. Vinyl chloride monomer flare instrumentation. 39------------------------------------------------------------------- -- CMA 005238 / / /. j \ '.i ! Re-traying of East hydrogen chloride column. t Permanent air monitoring systems in ali three cracking units. Corrosion-resistant vinyl chloride monomer stripper condenser. A method has been devised and tried which will eliminate em ployee potential exposure on much of the vinyl chloride monomer sampling. Hardware has been ordered to convert many sample points to closed sampling. A closed system for liquid blowdown from sodium hydroxide scrub bers Is over 50 percent complete. A system Is being worked out which will permit purging tank car loading lines to the flare before they are disconnected. A continuous analyzer for detecting water in vinyl chloride will eliminate the need for many samples now taken by operators. An additional large caustic scrubber to eliminate the need for small scrubbers is planned. This will permit all caustic scrub ber operators to be handled In one area, and not only reduce the nunber of employees potentially exposed, but additionally will make controlling emissions much more feasible. A program to eliminate pump seal leakage is under way. A full investigation of ethylene dichloride-vinyl chloride pumps has been completed, and specific programs have been started which promise reduced pump seal failures. Quotations are being evaluated on providing a corrosion-resistant stripper condenser which will Increase uptime and thus reduce ex posure due to scrubber operation and stripper repair. A sampling method is being sought which will eliminate purging vinyl chloride into the atmosphere during tank car sampling 40 CMA 005239 operations. One device has failed to be an improvement, but others will be tried. Reboiler venting system, Topping column revisions. Larger reboilers. Better level indicators and purges. Pump seal revisions. This list is not all inclusive but is indicative of the planning and efforts going into further improvements. The following job descriptions apply to the personnel that are directly Involved in the manufacture of vinyl chloride in this plant. Tank Farm Operator Receive empty tank cars, prepare them for loading, load vinyl chloride monomer tank cars, set valves in tank farm to direct flow of vinyl chloride monomer to and from various spheres, set valves in tank farm to pump in and out of ethylene dichloride tanks, pump vinyl chloride monomer by pipeline. East Furnace Operator Crack ethylene dichloride to hydrogen chloride and vinyl chloride monomer, purify vinyl chloride monomer, and pump to the tank farm; send hydrogen chlo ride to the Oxyhydrochlorination reactor. East Synthesis Operator I Receive hydrogen chloride from cracking and Catoxid and react the hydro gen chloride in ih* Oxyhydrochlorination reactor, run catalytic oxidation of byproducts to hydrogen chloride, recover ethylene dichloride from Oxyhydro- chlorination reaction, pump crude ethylene dichloride to North Synthesis for purification. 41 CMA 005240 East Spare Operator Help East Synthesis and Furnace Operators. North-South Furnace Operator Crack ethylene dichloride to vinyl chloride monomer and hydrogen chloride, send products to North or South purification trains. / North Cracking Operator I Purify vinyl chloride monomer-hydrogen chloride stream from North fur- naces, send hydrogen chloride to Oxyhydrochlorination reactor, send vinyl .chloride monomer to tank farm, recycle recovered ethylene dichloride, send \ byproducts to storage. North-South Spare Operator Help other North and South operators. Laboratory Operator Perform routine testing for process control and product approval using classical methods - pH meters, titration, weighing, viscosimeters, etc. Instrument Laboratory | Perform routine testing for process control and product approval using j gas chromatographs and other analytical instruments. 1' ; 1i i /' s Table 2 shows a list of job classifications for the vinyl chloride mono* * i mer processing personnel contacted during the survey, and the range of vinyl ; chloride in ppm that the personnel were exposed to during the survey. 42 | i t J l J ! CMA 005241 TABLE 2 VINYL CHLORIDE CONCENTRATION RANGE FOR PLANTS A, B, AND C Areas or Jot Classifications Loaders Operators (Plant) Area (Plant) Lab Technicians Area (Loading) Chromatographers Shift Supervisors Pipe Fitters Instrument Men A (ppm) .17-1.89 .13-2.45 .56-5.89 .04-4.36 <.01-.01 .03-.21 .02-.25 B. (ppm) 3.00-84.77 .01-3.46 .05-.38 .03-.88 .09-1.22 .02-.12 .01-.33 C (ppm) .06-21.8 .08-18.2 .59-7.06 .07-.11 .02-.27 .25-.55 .16-.41 High-Low Rani (ppm) .06-84.77 .01-18.2 .05-7.06 .03-4.36 <.01-1.22 .02-1.01 .03-.55 .01-.41 .02-.25 43 / CMA 005242 DESCRIPTION OF POLYVINYL CHLORIDE PROCESSING PLANTS SURVEYED Plant D This facility processes polyvinyl chloride resins and compounds into numerous extruded, molded, and bonded items and yarn. The company has been fabricating polyvinyl chloride products for 25 years. The present facility was started up in August 1971. The company normally employs 150 people and operates 24 hours a day on a 5-day-week basis. All manufacturing operations are performed inaoors in a modern, well-designed and -laid out plant. Approximately 50 people are in volved in the manufacture of polyvinyl products. The manufacturing pro cesses employed in the manufacture of polyvinyl products at this plant are*, bonding; in the lamination of extruded polyvinyl chloride with plated mylar, or printed polyvinyl chloride film to make automotive or decorative trim; compounding, in the mixing of polyvinyl chloride resin with plasticizers, fillers, lubricants, stabilizer, pigments, and other materials to produce a dry-blend compound; extrusion, in the conversion of dry-blend or pelletized compounds into continuous plastic strips of a predetermined cross section; fibers, in the extrusion of pelletized compounds into spools of colored yarns used for the manufacture of woven products; and molding, by the injection of polyvinyl chloride compounds into a heated mold to produce items having a definite size, shape, and color. Compounding at this plant is accomplished in ribbon-type blenders, and conversion of the dry-blend or pelletized compounds into a plastic mass takes place in the extruders and injection molders. No basic changes have been made to their polyvinyl chloride fabrication opera tions. Ventilation in the plant is provided by 16 roof-mounted exhaust fans with a total rating of 50,000 cubic feet per minute at 1/2-inch static pressure which provide an air change once every 30 to 35 minutes. The adjoining offices are air conditioned. 44 CMA 005243 Overall housekeeping is very good and the equipment has been installed in a well-planned, uncrowded manner. An enclosed, air-conditicned cafeteria area has been provided for breaks and lunches. Smoking is restricted to special areas. Special clothing is not required. The company does not have a vinyl chloride'surveillance program; however, I the plant has been surveyed for vinyl chloride concentrations by an insurance I company. The company uses bulletin boards and meetings to keep their employees I informed on health and safety programs. Figure 7 shows a flow schematic of the processes used by Plant D to manu facture polyvinyl chloride products. 1 45 CMA 005244 CMA 0 0 5 2 4 5 cn Plant D -~T- + --!> C D__p--r r F fo ^L, H --------- 1 G Legend: A - Bagged Materials B - Blender C - Storage Container D - Extruder E - Cooling Bath F - Cut-Off Machine G - Shipping Container H - Injection Molder Figure 7 Flow Schematic, Plant D Plant E This facility processes polyvinyl chloride resins into a wide variety of extruded and injection-molded products. The company has 21 years of experience in the manufacture of polyvinyl products. The company normally employs 260 people and all of the employees are con! sldered to be exposed to vinyl chloride. The plant operates on a 24-hour-per day, 5-day-per-week schedule, and all manufacturing operations are performed Indoors. The company uses the following processes in the manufacture of polyvinyl products: bonding, by hot-seal welding of flexible extruded profiles such as refrigerator seals; compounding, in the blending of polyvinyl chloride resin with plasticizers, fillers, stabilizers, pigments, and other additives in a semiautomated blender with a 45,000-pound-per-day capacity; extrusion, in the production of a wide range of profiles from powder-type compounds; and mold ing of dry polyvinyl chloride compounds Into items such as automotive seals and cable enclosures by injection molding. Ventilation throughout the plant is provided by air-circulating fans. Hoods vented to the atmosphere through a duct system have bee.- installed on irjection molding presses and the high-intensity compound mixer. Doors and windows are opened as required to assist the plant ventilation system. The only significant change in the plant is the addition,.in duly 1974, of the new high-intensity compound mixer. The mixer is vented to the atmo- 1 sphere through a duct system and should serve to reduce the escape of vinyl ^ chloride to the plant air. The company does not have a vinyl chloride sampling program and does not feel that it has concentrations of vinyl chloride above the permissible limit CMA 005246 \ \ t i' ,- M \% ;' i / /' / 1:' .. J > in the plant. Other than the polyvinyl chloride resin, none of the other com pounding ingredients used in the plant are recognized as liver toxins or cancer-producing chemicals. The company has an active safety and medical program. Figure 8 shows a flow schematic of the processes used by Plant E to manu facture polyvinyl chloride products. * X >r \ * *-V/ ;'' CMA 005247 CMA 0 0 5 2 4 8 / f-f If- r' ' iff i Plant E i / Legend: A - Bagged Materials B - Blender C - Storage Container D - Extruder E - Cooling Bath .F - Cut-Off Machine G - Shipping Container H - Injection Molder Figure 8. Flew Schematic,.Plant E Plant F This facility processes polyvinyl chloride resins into numerous dip- molded and dip-coated products using plastisol-type compounds. The company has been fabricating polyvinyl chloride products by the dip molding process for 25 years and normally employs 110 people. Due to the design of the plant, all of the employees are considered to be exposed to vinyl chloride. The plant normally operates on a one-shift-per-day basis, 5 days a week. The company added blow molding units 3 years ago. Blow-molded products are made from polyethylene compounds. This company uses the following three processes to produce polyvinyl chloride products: (1) compounding, in the mixing of polyvinyl chloride resins with dicapryl phthalate, dioctyl adipate, and tallates as plasticizers; barium, cadmium, and zinc organic solutions as stabilizers; pigments; and fillers (other than the resins, none of the other compound materials are known liver toxins); (2) molding, by dipping a heated mold into a plastisol compound and curing the dipped mold in an oven; and (3) plastisols, in the compounding of plastisol mixtures. The only change that has been made to their polyvinyl chloride manu facturing processes is the addition, 9 years ago, of an automated-conveyorized dip-molding line. All of the other dip-molding units are handoperated, batch-type units. Plant ventilation is provided by roof-mounted fans. All of the ovens and blow-molding units are equipped with hoods which are ducted overhead to the atmosphere for removal of fumes. The adjacent offices are air con ditioned. The company has an active safety program and they perform area and personnel sampling using the carbon tube sampling method. The carbon tubes 50 ~-.v \ CMA 005249 are analyzed by one of the polyvinyl chloride resin suppliers. The results of the sampling analysis are posted on employee bulletin boards along with other safety and health bulletins. Sampling results show a hi-lo range of <.01 to 18.0 Dpm. An enclosed cafeteria is provided for smoking, drinking, and eating during breaks and the lunch period. Figure 9 shows a flow schematic of the processes used by Plant F to manufacture polyvinyl chloride products. Legend: A - Bagged Materials B - Blender C - Mixing Tub D - Mixer E - Plasticizers F - Pigments G - Mold Heating Oven H - Plastisol Dip Tank I - Heated Mold J - Curing Oven K - Shipping Container CMA 0 0 5 2 5 1 Figure 9. Flow Schematic, Plant F Plant G This facility manufactures closed-cell expanded products from blends of polyvinyl chloride and rubber compounds. The manufacturing operations are performed in several indoor locations. The company has been making closed cell expanded polyvinyl chloride/rubber products for 19 years, and no essen tial changes have been made to the original procsss. I The plant operates on a 24-hour-day, 5-day-per week schedule and per- I forms a batch-type operation. The plant has 1,110 employees; however, only I 160 of their employees are exposed to vinyl chloride In their manufacturing operations. The manufacturing processes performed by this company involving polyvinyl chloride resins and compounds are compounding, extrusion, foams, and molding. The manufacture cf the various closed-cell expanded product line pro duced by this company begins with the addition, to a Bantury mixer, of pre determined amounts of the materials required to make the desired compound. The Banbury-mixed compound is fed to a two-roll mill where further mixing takes place, and ends up as a sheet of compound on the mill roil. Sections of the sheet are cut off and placed on a portable rack. The milled slabs are fed into a tuber (tube-type extruder) where the extruded compound for the batch-type units is cut into sections. The sections are placed In a multi-leaf platen press where the section is heated under pressure to a definite shape, and partial expansion takes place. The shaped pieces are removed from the presses, loaded onto racks, and moved to a second oven. The loaded racks are placed in the oven where the partially blown sections are further expanded to approximately four times in size. The racks are removed from the oven, and the expanded slabs are unloaded and stacked onto skids for packaging and shipment. % . 53 CMA 005252 In another building, the nilled slabs are fed Into a continuous tuber located at the head of a long tunnel-type oven. The tubed stock is cured and fully expanded into a continuous sheet in the oven. The expanded sheet is cooled and passed to a cutter where it Is cut into sections or rolled into rolls prior to packaging for shipment. In other operations, the milled sheet can be extruded through heated dies to form continuous profiles of closed-cell expanded extrusions. This type of product would be primarily used for gasket, insulation, or cushioning materials. The closed-cell expanded products can be coated with a plastisol com pound and further cured to provide a clear or colored skin of desired thick ness on the coated item. The company has established a program for personnel sampling using the metnod called out in the NIOSH publication PCN No. 178, Vinyl Chloride in Air and Personal Gas Sampling Pumps. Initial samples collected in May 1974 indicated less than 1 ppm of vinyl chloride for 10 area samples. The char coal tube samples were analyzed by an independent laboratory. Figure 10 shows a flow schematic of the processes used by Plant G to manufacture polyvinyl chloride products. 54 CMA 005253 Legend: ` A - Bagged Materials B - Banbury Mixer C - Two-Roll Mill 0 - Slab Rack E - Tuber F - Tunnel Oven 6 - Product Rolls H - Tube Rack I - Hot Press J - Oven Rack K - Batch Oven LShipping Container Figure 10. Flow Schematic, Plant 0 i Plant H This facility manufactures plasticized polyvinyl chloride calendered film and sheeting, expanded vinyl sheeting, and printed vinyl film. The company has been making calendered products 35 years, and expanded (foam) type products 8 years. The polyvinyl chloride plant normally employs 127 people and operates on a continuous basis 7 days a week. All production operations except the / offloading of resins from truck-mounted sealed containers to storage bins i located on the roof are performed -indoors. No basic changes have been made f to the manufacturing operations; however, a number of engineering improve ments have been initiated to improve production and eliminate unsafe working conditions. The company uses the following processes to produce the polyvinyl chloride products manufactured in this plant: bonding, in the lamination of two sheets of vinyl; calendering, in the conversion of a plastic mass of polyvinyl chloride compound into a film or sheet of controlled width and thickness; compounding, in the mixing of polyvinyl chloride resin with plasticizers, fillers, stabilizers, and other materials In ribbon-type blenders, and the conversion of the powdered blend into a plastic mass in Banbury mixers (color pigments and granulated trim are abided to the charge In the Banbury mixers); extrusion, in the processing of the Banbury charge through a screen and extruder head to a "rope" that is fed to the calender; fibers. In the combining of a roll of fabric with a sheet of polyvinyl chloride plastlsol; foams, in the expansion of a plastlsoi film in a blowing/ curing oven; plastlsols, in the compounding of plastlsol mixtures; and thermoforming, in the embossing of designs into polyvinyl chloride film and sheeting. 56 CMA 005255 Raw materials used in the production of polyvinyl chloride products are polyvinyl chloride resins, plasticizers, stabilizers (barium, cadmium, and zinc organic salts in solution form), fillers, pigments, and Celogen as a blowing agent. None of the above materials, other than the polyvinyl chloride resins, are known to be toxic to the liver. The plant uses overhead fans ducted to roof-mounted fans and stacks for ventilation. Hoods are located above equipment that gives off fumes, and the hoods are ducted to roof-mounted fans and stacks. The blenders and dryblend transport equipment are vented to the atmosphere through a dust col lector. The company has an active safety and sampling program and was willing to cooperate in the NIOSH survey. Thirty-minute briefings are given to all personnel, explaining the vinyl chloride monomer problem. Annual medical checkups are offered to all employees on a voluntary basis, plus a 6-month blood sampling and analysis program. Air sampling for personnel, and area sampling are employed to detect vinyl chloride, using the carbon-tube col lection method. In addition, Miran II infrared analyzers plus Century organic vapor analyzers are used to check for vinyl chloride. The charcoal tubes are sent to their test center or a commercial laboratory for analysis. The analysis on the charcoal tubes can also be performed at this site, The sampling program was initiated in April 1974, and the only change that has been made is an increase in the sampling frequency. The results of their sampling rrogram indicate a hi-lo vinyl chloride range of 0.2 to 1.1 ppm for their operating personnel. Housekeeping throughout the plant is good and their safety.department is doing everything possible to eliminate or reduce employee exposure to vinyl chloride belcw the permissible working levels. Employees performing 57 ChA 005256 operations where exposures above the permissible limit are possible must wear protective clothing. Smoking, drinking, and eating are permitted in enclosed air-conditioned cafeteria areas or offices. Figure 11 shows a flow schematic of the processes used by Plant H to manufacture polyvinyl chloride products. i \ 58 ./ CMA 005257 Legend: _A -^Roof Storage Silos B - Blender C - Dump Cart D - Storage Silo E - Weigh Hopper F - Banbury Mixer G - Extruder H - Conveyor . I - Calender J r Cooling Drums K - Winder L - Product Rolls Plant H Figure 11. Flow Schematic, Plant H plant I This facility processes polyvinyl chloride resins into pelletized polyvinyl chloride compounds, thermoforned products, vinyl film, and vinyl sheeting. The company has been performing calendering operations since 1946, thermoforming since 1958, and compounding since 1959. The company employs 520 people; however, only 3C9 of the employees are considered to be exposed to vinyl chloride. The facility operates on a 24hour-per-day schedule, 7 days a week depending on the work load. All of the production operations for the processing of polyvinyl chloride into finished products are performed indoors except for the offloading of resins to the roof-located storage hoppers, and the loading of compounded resins into bulk shipping devices. The manufacturing operations performed In the conversion of polyvinyl chloride resins into salable products are compounding, calendering, and thermoforming. Compounding involves the mixing of polyvinyl chloride resins, plasticizers, stabilizers, fungicides, bacteriastats, lubricants, pigments, and fillers in continuous ribbon-type blenders. After the ingredients are blended, they are further processed into a plastic mass, sheet, or rope in Banbury mixers, two-roll mills, extruders, or a combination of the three units. Calendering converts a rope of plastic polyvinyl chloride compound into a continuous sheet or film of controlled width and thickness in a four-roll in verted "L" form calender. The plastic compound from the Banbury mixer in another product line is passed to an extruder-dicer unit to convert the dryblend canpound into a pelletized compound product. The pelletized compound is bagged and loaded onto skids for shipment as a salable product. Thermoformed products are produced by the vacu-forming process. In this operation, precut sheets or polyvinyl chloride sheet stock are fed to a vacu-forming 60 CMA 005259 unit, where the sheet stock takes the form of the hot die, using negative pressure during the forming operation, and positive pressure to strip the formed item from the die. The formed items are stacked and loaded into boxes for shipment. The vacu-formed products are used as custom-formed plastic packaging for the protection and display of items such as candy and fruit. Roof-type ventilators are used throughout the plant for ventilation. Dust-producing equipment and dust-laden atmospheres are ducted to baghouses and cyclone separators to remove airborne particulate prior to venting to the atmosphere. The company has an active health, safety, and sampling program to protect Its employees and prevent vinyl chloride excursion to the atmosphere. Safety and health Information is transmitted to the employees by way of union-manage ment meetings, and bulletin boards. Carbon tubes and Sipin pumps are used to collect area and personnel samples. The air samples are analyzed by gas chromatography in their in-plant laboratory. The company is also very active in the development of more-advanced methods of identifying vinyl chloride concentrations in the work area through the use of instant readout instru mentation. The only suspected liver toxins that are used in this plant are vinyl chloride, polyvinyl chloride resins, organic lead stabilizers, and tetrahydrofuran. The tetrahydrofuran is restricted to laboratory analysis usage. The results of their sampling program were not available. The company Is constantly revising its production p'.jeedures and equip ment to take advantage of methods to increase production, lower operating costs, and Increase th" overall safety of its employees. The main changes that were made to the compounding operations are the changes in the mixing of compound ingredients In two-roll mills to Banbury mixers and then to ribbon-type blenders. 61 CMA 005260 VV t' 1- m.l' "/ A cafeteria and designated smoking, drinking, and eating areas have been provided for the employees. Respirators were not worn in the blender areas. Figure 12 shows a flow schematic of the processes used by Plant I to manufacture polyvinyl chloriue products. t (' ; ji ' I 62 CMA 005261 J /. / 1 / Legend: A - Silo Storage Tanks B - Weigh Hoppers C - Blenders D - Two-Roll Hills E - Banbury Mixer F - Dicer G - Bagger Unit H - Bagged Resins 1 - Calender 0 - Cooling Drums K - Winder L - Product Rolls t. Plant I Figure 12. Flow Schematic, Plant I Plant J This facility converts polyvinyl chloride resins and other compounding ingredients into calendered film and vinyl-coated supported and unsupported fabrics that are sold to a number of industries. The company has been in operation since 1947 for the manufacture of poly vinyl chloride produces. The plant normally operates on a 24-hour-per-day schedule, 5 to 6 days a week. A! ll manufacturing operations are performed indoors except the offloading of resin from bulk resin trucks to ground level storage silos. Resin J from the silos is transferred by an airveyor system to a gravity supply hopper located on the roof of the plant. The plant employs 325 people; however, only 50 workers ore considered to be exposed to vinyl chloride in their manufacturing operations. The fol lowing processes are used by this company to make their polyvinyl chloride product lines: bonding, in the lamination of two sheets of vinyl; calendering, in the high-speed conversion of a rope of polyvinyl chloride compound into continuous film or sheet stock of controlled width and thickness; compounding, in the mixing of polyvinyl chloride resins with plasticizers, stabilizers, fillers, lubricants, and other additives in ribbon-type blenders, and the con version of the powdered blend into a plastic mass in Banbury mixers (color pigments and granulated trim stock and scrap are added to the Banbury in the Banbury mixers); extrusion, in the processing of the Banbury charge through a screen and extruder head to form a rope of polyvinyl chloride compound that is fed to a calender; fibers, in the continuous combination of a sheet of fabric with a sheet of cast polyvinyl chloride film; foams, in the expansion of cast plastisol film in a blowing/curing oven; plastisols, in the compounding of plastisol mixtures used in the film casting line; and thermoforming, in the 64 ' CMA 005263 embossing of designs into polyvinyl chloride film and sheeting. The embossing operation is performed on the calendering lines and the cast film line. The plant uses roof-mounted ventilation fans, exhaust hoods, and ducts to supply fresh air and remove fumes and dust-laden atmospheres. The vented exhausts are passed through an electron precipitator to remove entrained solids prior to venting to the atmosphere. The solids collected in the precipitator are burned as a fuel. Recent changes that have been made to the ventilation system to reduce vinyl chloride concentrations within the plant are: a 30horsepower, roof-mounted exhaust fan and duct system has been installed on each of the blenders to prevent the excursion of dry-blend compounds into the plant air; shrouded hoods have been installed on the mills to reduce area; and conveyors to the mills have been enclosed. A proposal is in the design stage to enclose the Banbury mixers with a duct system similar to the systems installed on the ribbon blenders. The company has an active safety program and has recently initiated an area and personnel sampling program using the carbon tube method and personnel sampling pumps. The analysis of the carbon tubes is performed by an inde pendent laboratory. The employees are kept up to date on safety and health problems by way of bulletin boards and safety meetings. All employees enter ing work areas where higher-than-permissible levels of vinyl chloride have been found or are possible must sign a form that lists the specific work area entered, and the time the area was entered and exited. Chemical cartridgetype respirators are worn by the employees when working in dusty areas or when higher-than-permissible levels of vinyl chloride are suspected. A surveillance program for vinyl chloride was initiated In November 1974. The results of the survey to date indicate a hi-lo vinyl chloride concentra- 65 .4 CMA 005264 tier* range of <.l to 30.81 ppm based on area sampling over a period of 4 months. Eating, drinking, and smoking are restricted to specified areas or en closed office areas. Figure 13 shows a f'ow schematic of the cast film production line for Plant J. Figure 14 shows a flow schematic of the calendered film lines for Plant 0. During the field surveys in the polyvinyl chloride processing plants, it was found that all tasks were performed by several job classifications; there fore, the job classifications were grouped by similar tasks as shown on page 69. i 66 7 CHft 005265 9 9 S S 0 0 VWD I 1 o CO Figure 14. Flow Schematic', Calendered Film Production, Plant J i CMA 0 0 5 2 6 7 JOB DESCRIPTIONS FOR POLYVINYL CHLORIDE PROCESSING PERSONNEL Blenders - Blender Operators Blender operators charge polyvinyl chloride resins and other compound materials such as plasticizers, stabilizers pigments, toners, fillers, lubricants, blowing agents, autix-oxidants, fungicides, santicizers, and modifiers into ribbon or high-intensity blenders and mix the above ingre dients to prepare dry-blend compounds. Banbury Mixers - Banbury Operators Banbury Operators convert dry-blend compounds, or compounds made up from the individual ingredients required to prepare a compound, into a dough-like ot plastic-like mass and then feed the plastic mass to an ex truder or mill. They may also add scrap from the extruders or calenders to the Banbury charge for incorporation into the virgin compound. Hill Hen - Mill Operators - Feed Mill Operators Hill operators convert dry-blend compounds. Banbury-mixed compounds, or compounds made up from the individual ingredients required to prepare a compound, into a plastic sheet. They may also add scrap from the ex truders or calenders to the dry-blend or Banbury-mixed compounds in the milling operation. They may feed a strip of the plastic sheet from the mill to an extruder, tuber, or calender, or remove the stock from the mill as a roll or in sheet form and feed it to a tuber or extruder. Extruders Extruaer* convert blender-mixed, Banbury-mixed, or mill-mixed compounds Into pugs, ribbon, or ropes which are fed to equipment such as a calender. They also maintain screens that are installed in the extruder ahead of the extrusion die to prevent trash or slugs of compound from entering the die. 69 CHA 005268 Menders Molders operate molding equipment such as blow molders, injection molders vacu-forming units, and embossing equipment to convert a plastictype compound into molded items. Compounders / Compounders mix polyvinyl chloride resins with the other ingredients /required to prepare a compound in blenders, Banbury's, mills, or paddle- Mlxers - Mixer Operators - Plastlsol Blenders Mixer operators mix polyvinyl chloride resin with the other Ingre dients required to prepare plastisol-type compounds in a stirred mixer equipped with an agitator. Color Welchmen Color weighmen weigh out the colors or pigments that are used to prepare colored compounds. Tuber Operators Tuber operators are responsible for the operation of tube-type extruders. Tuber feeders Tuber feeders feed milled compounds in sheet or strip form to tube-type extruders. "Oilmen I iI Oilmen weigh out lubricants and other oil-like compounding additives, and add them to the compounds that are being prepared. Foam Line Chief The foam line chief is responsible for the operation of the foam-cast ing line. \ 70 CMA 005269 Calender Chief The calender chief is responsible for the overall operation of a calender line. Assistant Operators An assistant operator assists the calender chief or the foam line chief in the operation of a calender line. Film-casting line, or foam casting line and relieves the chief during break and lunch periods. Press Operators Press operators operate the leaf-type platen presses that shape the polyvinyl chloride/rubber slabs and perform the initial blowing and curing operation. Finishers Finishers perform final operations, on extruded products. These oper ations include cutting to length and shape, perforating, bonding of two or more lengths together for refrigerator gaskets, inspecting the finished item, and packing the finished item in boxes for shipment. Dippers Dippers remove the heated molds from the preheat oven and transfer them to the dipping unit, operate the plastlsol dipping unit, remove the plastisolcoated mold from the dipping unit, and transfer the mold to the curing oven. Line and Dip Operators Line and dip operators remove the molds from the plastisol curing ovens; strip the cured plastisol products from the mold; dip the stripped mold in the mold release solution tank, or spray the mold with a release agent; trans fer the mold to the preheat oven; Inspect the molded product; and stack the molded products in boxes for shipment or additional operation. They also assist or relieve the dippers. 71 CMA 005270 Set-up Men Set-up men are responsible for changing polyvinyl chloride processing equipment to make a different product line and to correct problems with the equipment under operation in the manufacture of a product. Maintenance Men or Mechanics Maintenance personnel or mechanics are responsible for the repair of all the equipment used in the plant, to include: the equipment used to manufacture a product; instrumentation; lighting and other electric equip ment; heating, air-conditioning, and ventilation systems; trucks; conveyor systems; and any other equipment requiring repair. Truck Drivers Truck drivers unload raw materials from trucks or railcars and transfer raw materials, compounds, semifinished products, and finished products between work stations and storage areas. Tower Workers Tower workers are responsible for the unloading of raw materials delivered to the plant in bulk containers to ground-level and roof-level raw material storage silos, the transfer of the raw materials from the storage silos into the weigh hoppers, and the dumping of the weigh hoppers into the blenders or Banbury mills. Wind-up Men Wind-up men operate the equipment that winds calender line, cast line, or foam line products onto ??ner shells; weigh packages; and unload the wound products onto skids for shipment. Dicer Operators Dicer operators operate the extruder, chiller, cut-off unit, and air- transfer equipment used in the manufacture of pelletized components. 72 Baggers Baggers are personnel that weigh and fill paper bags with pelletized compound, label the bags, and load the filled bags onto shipping skids. I Driver-Baggers Driver-baggers transfer the bagged pelletized compound skids from the bagging station to the warehouse area, supply skids for loading, and relieve the bagger during break periods. lab Hen - lab Personnel - Lab Technicians I Lab personnel and technicians work in the research and development I laboratories, product control laboratories, and analysis laboratories. Foremen Foremen are responsible for the safety, health, and productivity of the employees working under their jurisdiction, the equipment in their area, and the quality and quantity of the product manufactured in their area. Supervisors Supervisors are normally responsible for all of the operations and personnel involved in their area of responsibility, and generally have two or more foremen working for them. Project Engineers > Project engineers are generally responsible for designing the equipment required to manufacture a product, and for solving problems of manufacturing, equipment, and products. | Table 3 shows a grouping of job classifications for the polyvinyl chloride processing personnel contacted during the survey, and the range of vinyl chlo ride in ppm that the personnel were exposed to during the survey. The following job classification groupings serve to clarify the types of personnel within each classification. .V CHrt 005272 Calender Personnel Assistant Operators Chief Operators Calender Operators Wind-up Man Compounding Personnel Banbury Operators Blender Operators Color Weighman Compounders Feed Mill Operators Mill Operators Mixer Operators Plastisol Blenders Tower Workers Extrusion Personnel Extruders Foremen Project Engineers Project Supervisors Tuber Feeder* Tuber Operators Dipping Personnel Dippers Foremen Line Girls Line and Dip Girls Set-up Men Pelletizer Personnel Baggers Dicer Operators Driver-Baggers Molding Personnel Moldars Press Operators Laboratory Personnel Laboratory Technicians Maintenance Personnel Maintenance Men Mechanic Miscellaneous Personnel Finishers Foam Line Chiefs Truck Drivers 74 CMA 005273 TABLE 3 VINYL CHLORIDE CONCENTRATION RANGE FOR PLANTS D, E, F, G, H, I, AND J IN PPM i ~~ Areas or Job Classifications D E FG H I J Calender Personnel <.01 .50-2.44 .02 Pelletizer Personnel .02-.76 n i o * V too 1 o Compounding Personnel <.01-.02 .01-.27 N.D. .24-.69 Laboratory Personnel <.01 .02-.68 Molding Personnel <.01-.03 N.D. PI as tl sol Dipping Personnel <.01-.06 Extrusion Personnel Maintenance Personnel <.01-.02 <.01-.02 <.01-.02 N.D. <.01 i Miscellaneous Personnel <.01-.02 N.D. <.01 Area <.01-.01 .37 N.D. N.D. <.01 A o o Low HI Avr <.01 2.44 .85 .02 .76 .39 <.01 .65 .16 <.01 .62 .03 i <.01 .03 .02 <.01 .06 .01 <.01 .02 .01 <.01 .02 .01 <.01 .02 .01 <.01 .37 .13 SAMPLING PROCEDURE All personnel samples were collected on Lot Number 101 organic vapor charcoal tubes supplied by the Anatole ). Sipin Company, using Model SP-1 Sipin pumps. The pumps were set to operate as nearly as possible at a flow rate of 50 milliliters per minute, and to limit the volume of air sampled by each tube to 5 liters for Plants A, B, C, D, E, F, and G. The volume of the air sampled for each carbon tube used In Plants H, I, and 0 was Increased to approximately 10 liters when the analysis of the carbon tube samples col lected at the polyvinyl chloride product manufacturing Plants 0, E, F, and G indicated that the vinyl chloride detected in the atmosphere in Plants D, E, F, and G was less than 0.02 ppm. The personnel samples were collected from the breathing zone of the worker, with the carbon tube mounted in a lapel-type holder. The area sam ples were collected in a similar manner, with the tubes located in such a position as to represent the breathing zone of an employee working on the equipment. All of the carbon tube samples collected during the vinyl chloride sur vey were analyzed sing the procedures set forth in the NI0SH Vinyl Chloride report, P&CAM #127/* with the exceptions that Poropak type QS at 100 C, and 0.4 percent Carbowax 1500 on Carbopak A at 50 C were used as the chromato graph column materials. This procedure requires the separation of the charcoal contained in the front (100-milligram) and back (50-milligram) sections of the charcoal tube, 2lbld. 76 \\ CM/A 005275 1lT' -t*." / \ \ and the addition of each section of charcoal into 1 milliliter of carbon di sulfide in a 2-milliliter glass septum vial. Each vial is then capped with a septum closure. The vials are then agitated to ensure that the gases ab sorbed by the charcoal are dissolved by the carbon disulfide. A 5-microliter aliquot from each vial is injected into the inlet port of a gas chromatograph with chart readout. The height of the vinyl chloride peak is measured for each section and used in the following calculations to determine the amount of vinyl chloride absorbed by the charcoal In each char coal tube in ppm. The weight, in ug, corresponding to each peak area is read from the standard curve for vinyl chloride. No volume corrections are needed, because the standard curve is based on ug/1.0 me CS2 and the volume of sample injected is identical to the volume of the standards in jected. Corrections for the blank are made for each sample, vg B wgs - u9b where: U9S " v9 found in front section of sample tube ug = pg found in front section of blank tube A similar procedure is followed for the backup sections. These values are further corrected for the desorption efficiency at the level c vinyl chloride measured. Corrected pg3 = td-e--s-o--r-prtiroVn9efficieL-n--c-y-- The corrected amounts present in the fi'ont and backup sections of the same sample tube are added to determine the total amount of vinyl chloride in the sample. CKA 005276 The concentration of the vinyl chloride in the air sampled is ex pressed in mg/m3, which is numerically equal to yg/liter of air. mg/m3 * vg/i = tqtal^(Section 10.4) where: V is the volume of air sampled Another method of expressing concentration is ppm, defined as yt i of vinyl chloride gas/liter of air. ppm = ug/i .. 24.45 ,, 760 .. T+273 * 6175" * P x "255" where: P = pressure (mm Hg) of air sampled T = temperature (C) of air sampled 24.45 = molar volume (i/mole) at 25C and 760 urn Hg 62.5 = mo'ecular weight (g/mole) of vinyl chloride 760 = standard pressure (mm Hg) 298 = standard temperature (K) SAMPLING RESULTS A number of air velocity measurements were made in several of the poly vinyl chloride processing plants using an Alnor Velometer Or, meter. In open areas where the personnel were working, no air movement could be detected using the velometer, except where pedestal-type fans were employed to circulate the air. Measurements taken at the breathing zone level of an employee working beneath a ducted exhaust hood gave a zero reading; however, when a smoke tube was used, air movement into the hood was readily detected. Velometer readings were made at the edge of heeds and on Mender charg ing door screens with varying results depending on where the meter was posi tioned on any one hood or charging door. Based on the above observations. 78 CMA 005277 the velometer readings were found to be meaningless and were not included as data in tins report. The results of the analysis of the organic vapor carbon sampling tubes collected during the vinyl chloride surveys performed at the vinyl chloride manufacturing Plants A, B, and C, and the polyvinyl chloride product manu facturing Plants D, E, F, G, H, I, and J are shown in the following Vinyl Chloride Concentration Data Sheets. v\ I CMA 005278 \x -"0,; /: ' -I : i' v * VINYL CHLORIDE CONCENTRATION DATA PLANT A Job Classification Date Worker & Sample Time Volume VCL Code Shift Number (min) (li ters) (ppm) TV/A Lab Tech Loader Operator Operator Loader Instrument Man Lab Tech Shift Supervisor Shift Supervisor' A-9 12/3/74 156 1 . 159 162 165 A-7 12/3/74 160 1 163 166 167 A-5 12/3/74 1 18 23 39 A-2 12/2/74 2 O/ 10 13 15 A-3 12/2/74 148 2 150 152 154 A-6 12/3/74 1 . 19 22 21 37 A-8 12/3/74 155 1 157 161 164 A-l 12/2/74 2 - A-4 12/3/74 1 2 6 9 12 20 41 43 92 5.046 4.36 90 90 5.143 5.282 .27 .05 1 27 90 5.561 .32 93 4.340 .10 95 4.701 .74 1 07 90 4.129 1.62 88 4.217 1.89 90 3.342 0.21 108 4.235 2.45 1.03 90 3.529 0.13 96 4.012 0.74 90 3.797 0.22 90 3.843 1.57 60 2.680 0.17 70 85 3.781 0.17 90 4.038 0.32 85 4.303 0.35 58 2.912 0.41 30 97 3.363 0.25 88 3.216 0.09 92 3.363 0.02 SO 3.329 . 0.32 17 90 4.319 .37 90 4.301 .07 93 4.487 .04 89 4.521 .15 93 5.138 0.04 92 4.758 0.08 90 4.598 0.20 90 4.667 0.13 11 100 4.618 0.03 90 3.922 0.04 .09 92 3.852 0.21 80 CMA 005279 VINYL CHLORIDE CONCENTRATION DATA 1 ! \A \ l 1 CMA 005280 VINYL CHLORIDE CONCENTRATION DATA 82 CMA 005281 VINYL CHLORIDE CONCENTRATION DATA PLANT 8 Job Classification Date Worker & Sample Time Volume VCL Code Shift Number (min) (liters) (ppm) TWA Compressor Operator B-9 12/10/74 130 1 . 127 123 121 Tower Operator 8-14 12/12/74 3 ` 69 73 77 81 Control Room Curator B-2 12/12/74 139 3" 136 134 100 Lab Tech B-4 12/12/74 141 3 137 97 101 Chromatographer B-13 12/11/74 1 27 31 33 143 Control Room Operator B-6 12/10/74 131 1 128 125 122 Area Samples Loading 1 -_ Outside Compressor House 12/11/74 1 12/10/74 1 57 60 62 64. 65 48 46 51 54 90 4.080 .06 90 3.275 .14 90 2.591 .11 90 3.192 .13 .11 90 3.826 .20 90 3.701 .06 90 3.851 .02 90 4.006 .09 no 92 4.409 .10 88 3.374 .06 89 3.691 .06 91 3.523 .07 07 91 4.263 .16 90 3.868 .006 93 3.752 .09 86 3.539 .03 07 88 4.706 .06 90 4.199 .02 88 3.981 .12 93 3.983 .06 .06 90 4.267 .01 90 4.542 .06 88 4.573 .04 92 4.397 .05 .04 60 2.357 1.22 67 2.661 .09 60 2.477 .20 90 3.881 .36 90 4.203 .31 90 3.165 .12 90 3.117 .12 91 3.302 .14 90 3.224 .25 .41 83 CMA 005282 VINYL CHLORIDE CONCENTRATION DATA 'LANT B Job Classification Worker Code Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Area Samples (continued) Outside Compressor House 1| 1l Stock Room 1 Cracker 12/12/74 3 67 ' 70 75 79 B-12 12/11/74 1 26 30 35 144 12/11/74 56 1 90 3.496 .17 90 3.225 .15 90 3.337 .12 90 3.210 .09 13 88 4.706 .06 90 4.862 .006 90 4.799 .05 94 4.969 .38 13 360 14.223 .09 .09 84 CMA 0052S3 VINYL CHLORIDC CONCENTRATION DATA PLANT C Job Classification Worker Code Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Tank Farm Operator C--21 12/19/74 2. 247 242 239 237 Tank Farm Operator C-22 12/19/74 2 246 243 240 238 VC1 Operator East C-10 12/17/74 1 169 175 179 95 Tank Farm Operator C-23 12/19/74 2 245 244 241 236 VC1 Operator East C-6 Purification Operator C-l North 12/16/74 2 12/16/74 z 182 184 189 191 194 199 203 88 Tank Farm Operator C-18 12/18/74 1 91 94 220 222 Tank Farm Operator m Synthesis Operator East C-l 7 12/18/74 1 C-9 12/17/74 1 93 219 221 223 171 174 178 90 90 4.513 17.6 90 no 4.509 0.06 5.154 21.8 11.03 73 3.287 0.23 91 3.850 6.19 89 3.947 0.34 8 22 114 5.055 20.1 66 1.817 1.13 91 4.968 18.2 91 90 5.182 0.61 5.141 0.37 5 06 88 4.701 0.88 91 3.974 1.74 89 3.895 0.09 4.96 109 5.637 14.5 71 2.753 0.37 93 4.925 6.24 88 90 4.944 0.22 4.852 0.21 2.20 89 4.620 1.95 91 4^672 3.35 90 4.569 0.20 90 4.358 0.25 90 4.725 0.10 98 90 4.051 1.50 90 4.124 0.98 91 4.083 0.34 90 3.982 0.99 95 90 3.939 0.67 90 3.903 2.31 91 4.144 0.35 90 3.759 0.38 92 4.679 0.49 90 4.432 0.57 90 4.484 0.34 88 4.168 0.27 .93 AO 85 /' CMA 005284 VIHYL CHLORIDE CONCENTRATION DATA PLANT C Job Classification Worker Code Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Maintenance Coordinator C-8 12/17/74 * 1. Spare Operator C-ll 12/17/74 1 Purification Operator C-4 12/16/74 South 2 Spare Operator East C-5 12/16/74 2 Pipe Fitter North & South C-16 12/17/74 1 G. C. Operator C-19 12/18/74 1 Purification Operator South t\ Spore North & South C-13 12/17/74 1 C*-2 12/16/74 2 - Synthesis Operator East C-7 12/16/74 2 170 173 177 89 172 176 180 96 195 198 202 85 181 186 187 108 103 112 117 206 207 211 214 217 104 109 114 119 192 196 200 86 183 185 188 190 89 5.216 90 5.186 90 5.238 92 5.079 0.55 0.52 0.28 0.25 90 4.533 90 4.171 90 3.980 90 3.492 0.62 0.38 0.27 0.22 91 4.687 90 4.561 90 4.338 90 4.355 0.46 0.19 0.66 0.09 96 5.038 0.11 84 3.905 0.21 90 4.-C22 0.21 89 5.330 . 0.75 90 4.179 90 4.299 91 4.241 92 4.172 90 5.067 88 4.983 93 3.712 89 4.714 0.41 0.32 0.16 0.32 0.03 1.01 0.06 0.04 90 4.675 90 4.613 90 4.717 90 4.698 0.51 0.15 0.11 0.24 88 4.552 90 4.497 90 4.835 91 4.621 0.40 0.20 0.17 0.13 89 4.999 92 5.310 90 5.241 39 5.493 0.11 0.21 0.21 0.33 40 X] 09 * <J\L0 .30 .28 OK 22 86 CMA 005285 'rh-ivi'** VINYL CHLORIDE CONCENTRATION DATA PLANT C Job Classification Worker Code Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Furnace Operator .North & South / 1i Purifi cation, Operator North i 1 1 I Spare Operator North & South ' Furnace Operator North & South C-3 12/16/74 2. C-14 12/17/74 1 C-15 12/17/74 1 C-12 12/17/74 1 G. C. Operator C-24 12/19/74 2 Instrument Lab Operator C-20 12/18/74 Wet-Lab Operator Area Samoles Plant Scrubbers 4* C-25 12/19/74 2 12/18/74 1 193 197 201 87 105 110 115 120 106 111 116 205 102 107 113 ns 224 227 230 233 208 210 213 216 225 229 232 235 209 212 215 218 92 4.872 0.28 90 90 4.912 0.22 4.716 0.20 .20 90 4.816 0.11 90 4.755 0.13 90 4.786 0.09 90 4,679 0.12 90 A. 827 0.22 UL 90 4.628 0.12 90 4.398 0.08 90 4.781 0.15 90 4.945 0.20 1A 90 5.026 0.10 90 4.796 0.10 90 4.850 0.13 90 4.547 C.i9 13 90 4.383 0.19 87 4.615 0.10 90 4.758 0.08 93 4.893 0.06 11 85 5.133 0.02 90 92 5.230 0.27 5.319 0.07 1<0u 93 5.290 0.04 92 5.278 0.09 88 90 4.069 5.043 0.11* 0.09 tl0l70 90 5.026 0.07 *' 90 3.274 7.06 90 3.260 1.60 3 25 90 3.315 1.61 90 3.451 2.73 < ?i i CMA 005286 VINYL CHLORIDE CONCENTRATION DATA PLANT C Oob Classification Area Samples (continued) VC Reflux Pumps North * North Plant Worker Code Date & Sample Time Volume VCL Shift t Number (min) (liter^j (ppm) TV/A 12/19/74 2 12/18/74 1 226 228 231 234 92 98 4.821 0.59 87 90 3.530 3.626 1.15 5.19 2.49 90 3.678 3.17 465 17.394 0.57 .57 Front Only Est. Bad' Section. * * 88 \ S' .i .* ; i CMA 005287 VINYL CHLORIDE: COriCEHTjtATIOri DATA PLANT D 89 CMA 005288 VINYL CHLORIDE CONCENTRATION DATA Job Classification PLANt 0 ----------l_ Worker Code Date fi Sample Shift} Number Time (min) Volume (liters) VCL (ppm) TWA Project Supervisor j Project Supervisor | 1' D-5 2/5/7$ 337 92 4.713 N.D. 1 . 341 345 88 4-447 125 6.218 .01 .01 <.Ql 349 55 2.742 .01 0-5 2/6/75. 353 90 4.264 <.01 1T 357 361 120 90 5.517 4.597 <.01 <.01 . <.01 365 60 . 3.148 <.01 Project Engineer D-4 2/4/7$ 320 97 5.097 <.01 1 325 330 73 100 3.577 <.01 4.834 <.01 <01 334 90 4.597 .01 Project Engineer Area Sample; D-4 2/5/7$ 336 90 4.485 .01 1 340 90 4.506 .01 344 116 5.710 <.01 348 65 3.285 .01 *UAT1 Extrusion on Top of Extruder #6 Top of Extruder #6 \ Blending Room Blending Room . * 2/5/7$ 339 90 4.882 .02 1 343 90 4.713 .01 347 100 6.078 .01 351 80 3.829 .01 AUT1 '2/6/7$ 355 90 4.600 .01 1 359 120 6.247 .01 363 90 4.666 .01 367 60 3.159 <.01 .01 2/3/79 300 120 5.010 <.01 1 306 ; 310 60 2.559 .01 ^ A1 90 3.760 N.D. 314 90 3.909 N.D. 2/4/75 319 90 3.940 <.01 1 324 91 4.217 N.D. * AT 329 120 5.690 <.01 335 60 3.169 <.01 J 3 i wjop fc------------ - CMA 005289 VINYL CHLORIDE CONCENTRATION DATA PLANl( E Job Classification - -i Date Worker & Code Shift Sample Number lime Volume VCL (min) (liters) (ppm) TWA Mixer Compounder Lab Personnel Extruder Molder Lab Personnel Maintenance Extruder Finisher `* E-8 2/11/75 397 1 403 409 4.15 90 4.474 .15 90 4.452 .11 90 4.550 .27 90 4.588 .11 E-5 2/10/75 376 1 380 387 394 90 4.1 IS .03 89 4.109 .06 91 4.517 .02 90 4.251 .01 E-l 2/10/75 372 91 4.487 .05 1 379 89 4.706 .06 386 100 5.520 .01 393 81 4.405 .02 E-3 2/10/75 374 1 382 389 368 90 4.444 .02 90 4.474 .01 93 4.659 .01 87 4.484 .02 E-4 2/10/ 75 375 1 381 388 395 E-7 2/11/ 75 396 1 402 408 414 90 4.577 .03 90 4.452 .02 90 4.346 .02 90 4.548 .01 90 4.798 .04 90 4.901 .01 90 4.798 .02 90 4.904 .01 E-6 2/10/75 377 1 384 391 370 90 4.351 .02 95 4.737 .01 99 4.408 .01 89 4.351 .01 E-10 2/11/ 75 399 1' 405 411 417 90 4.355 .01 90 3.821 .01 91 4.548 <.01 89 4.435 <.01 E-2 2/10/75 373 1 383 390 369 90 4.569 .02 91 4.G62 .01 92 4.624 .01 87 4.629 .01 .16 .03 03- .02 1 02 .02 mUi .01 m 91 .M^rnm CMA 005290 VINYL CHLORIDE CONCENTRATION DATA PLANT E Job Classification Worker Code Date & 1 Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Molder Finisher Maintenance Area Samples Mixing Deck E-9 2/11/7 5 398 1 404 410 416 E-Il 2/11/7 5 400 1 406 412 418 E-12 2/11/7 5 401 1 407 413 419 90 3.850 .01 90 4.489 <.01 m 90 4.525 <.01 90 4.331 <01 90 4.542 .01 90 90 4.617 <.01 4.142 <.01 < 01 90 4.659 <.01 90 4.697 .02 90 4.715 <.01 < 01 90 4.635 <.01 SO 4.636 <.01 2/10/7 5 1 378 385 392 371 90 4.. 387 90 4.389 92 4.401 88 4.366 .24 .43 .13 .68 *Y7 ) ! 1 VINYL CHLORIDE CONCENTRATION DATA PLANT F . Oob Classification Worker Code Date & Shift Sample Time Volume VCL Humber (min) (liters) (ppm) TWA Dipper (Automatic) 1 I Line & Dip (Hand) ; i Line & Dip (Hand) Set-Up Han Foreman Mixer Line Girl (Hand) Mixer * .* Dipper (Hand) F-2 2/12/ 75 432 1 . 420 95 5.168 .06 96 5.437 c.Gl 428 91 5.128 <.01 438 101 5.987 N.D. 02 F-3 2/12/ 75 437 93 4.817 .06 1 422 87 4.300 .01 429 101 5.101 <.01 442 98 4.887 N.D. n? F-5 2/12/75 436 1 424 431 440 90 4.725 .04 89 4.735 .01 95 5.106 N.D. 98 5.241 N.D. Ul F-6 2/12/75 435 89 4.844 .03 1 423 83 4.474 .01 430 102 5.331 <.01 443 101 5.217 N.D. 01 F-l 2/12/ 75 434 105 5.576 .02 1 421 87 5.163 .02 426 99 6.024 <.01 439 103 6.061 <.01 AU11 F-4 2/12/ 75 433 92 5.170 .02 1 425 86 4.862 .01 - m 427 103 5.485 <-01 441 101 5.230 N.D. F-9 2/13/ 75 447 94 4.735 <.01 1 463 466 87 93 4.292 N.D. 4.636 <.01 < 01 455 102 5.294 N.D. F-4 2/13/ 75 445 98 5.356 <.01 1 461 90 4.765 N.D. > m 467 91 5.192 N.D. 453 106 6.382 N.D. F-8 2/13/ r5 446 98 5.287 N.D. 1 462 88 4.957 N.D. u n 459 93 5.194 N.D. 454 103 5.903 N.D. '13 CMA 005292 VINYL CHLORIDE CONCENTRATION DATA PUNT F Job Classification Worker Code Date & Shift Sample Time Volume VCL lumber (min) (liters) (ppm) TWA Dipper (Hand) F-10 2/13/75 448 94 4.916 N.D. 1 . 464 450 87 4.433 N.D. w n 93 4.589 N.D. 456 102 5.518 N.D. Lab Tech F-7 2/13/75 444 1 460 458 452 93 4.830 N.D. 90 4.765 N.D. 99 5.184 N.D. 96 5.082 N.D. nn Area Samples Above ft Left of Mixing Unit (Breathing Zone) 2/13/75 449 102 5.795 N.D. 1 465 87 4.884 N.D. 451 93 4.929 N.D. 457 101 5.507 N.D. mn 94 ..L J'UJOM'VSJ* CMA 005293 VINYL CHLORIDE CONCENTRATION PITA PLANT I* Job Classification Worker Code Date 6 Sample Time Volume VCL Shift Number (min) (liters^ (ppm) TWA Compounder Banbury Mixer Banbury Mixer Mill Operator Mill Operator Millmart Tuber Feeder 1 Tuber Operator Press Operator G-4 2/18/7fe 480 93 4.619 N.D. 1 . 483 95 4.643 N.D. 488 108 5.389 N.D. 492 91 4.207 N.D. 6-1 2/17/7^ 468 89 4.800 N.D. 1 471 90 4.991 N.D. 474 90 5.028 N.D. 477 101 5.488 N.D. G-l 2/18/7t 481 92 4.778 N.D. 1 484 95 4.688 N.D. 489 108 5.389 N.D. 493 86 4.457 N.D. G-2 2/17/7: 469 1 472 475 478 94 5.123 N.D. 83 4.669 N.D. 89 5.279 N.D. 99 5.637 N.D. G-L 2/18/7! 482 92 5.011 N.D. 1 485 94 4.968 N.D. 490 108 5.513 N.D. 494 87 4.447 N.D. G-7 2/19/7! 497 94 5.298 N.D. 1 502 83 5.029 N.D. 507 88 5.314 N.D. 512 . 106 6.346 N.D. G-8 2/19/7! 498 93 4.931 N.D. 1 503 83 4.445 N.D. 508 88 4.837 N.D. 511 106 5.877 N.D. G-9 2/19/7! 499 93 4.483 N.D. 1 505 82 3.937 N.D. - * 509 88 4.244 N.D. 514 106 5.247 N.D. G-3 2/17/7! 470 82 4.038 N.D. 1 473 31 4.061 N.D. 476 90 4.465 N.D. 479 107 5.395 N.D. VINYL CHLORIDE CONCENTRATION DATA PLANT G Job Classification Worker Code Date & 1 ample Time Volume VCL Shift umber (min) (liters) (ppm) TWA Press Operator 1 Receiving Dock Truck Driver , ,j Area Samples Compounding G-5 2/18/75 487 91 5.292 N.D. 1 . 486 93 4.911 N.D. 491 110 7.029 N.D. 495 85 5.373 N.D. G-6 2/19/75 496 99 4.840 N.D. 1 501 83 4.133 N.D. 506 87 4.295 N.D. 513 106 5.231 N.D. 2/19/75 500 90 4.204 N.D. 1 504 90 4.063 N.D. 510 89 2.580 N.D. 515 132 6.178 N.D. ` * i j i * 96 CMA 005295 VINYL CHLORIDE CONCENTRATION CATA PLANT H Job Classification Worker .Code Date & Sample Time Volume VCL Shift Nunber (min; (liters) (ppm) TWA Blender Operator Blender Operator Mixer Operator Oil Man Foam Line Chief Calender Chief Calender Chief Mechanic Blender Operator Blender Operator Area Samples L-1000 Blender L-3000 Blender H-2 3/12/75 521 1 , 523 H-l 3/13/75 531 1 535 H-5 3/12/75 525 2 528 H-4 3/12/75 524 2 527 H-6 3/12/75 526 2 529 H-3 3/12/75 520 1 522 H-3 3/13/75 532 1 536 H-7 3/13/75 530 1 534 H-l 3/11/75 516 1 518 H-2 '3/11/75 517 1 519 180 9.743 .13 180 9.506 <.01 180 10.714 <.01 181 10.378 <.01 187 9.090 <.01 181 8.506 <.01 183 9.032 <.01 181 3.635 <-01 180 8.705 <-01 180 9.054 <.01 180 10.317 <.01 182 10.287 <.01 180 9.576 <.01 181 9.634 N.D. 184 8.838 <.01 176 8.729 N.D. 192 10.726 N.D. 180 10.154 N.D. 182 9.488 N.D. 180 9.495 N.D. 07 ^ ftl -< ft! ^M ** *U i <*U l ^ nl 3/14/75 1 3/14/75 1 533 !538 $37 539 180 10.632 180 11.456 180 8.771 180 10.085 <.01 <.01 <.01 <.01 <*UI <> *UrtIi . VINYL CHLORIDE CONCENTRATION DATA PLANT I Job Classification Worker Cede Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA . 5-L Wind-up Man 5-L Wind-up Man 5-L Wind-up Man 5-L Assistant Operator Dicer 11 Blender Operator Dicer II Blender Operator 5-L Blender Operator 5-L Banbury Operator - Dicer II. Mi liman' Dicer II Driver-Bagger 5-L Miliman i Dicer II Operator R&D Lab Technician * 5-L-Mlliman Dicer II Bagger 1-10 3/18/75 1. 1-9 3/18/75 1 1-8 3/18/75 1 1-11 3/18/75 1 1-4 3/17/75 1 1-1 3/17/75 1 1-3 3/17/75 1 1-2 3/17/75 1 1-5 3/17/75 1 1-13 *3/19/75 1 1-7 3/18/75 1 1-16 3/19/75 1 I-1C 3/19/75 1 1-6 3/17/75 1 1-14 3/19/75 1 555 561 554 550 553 559 556 563 543 546 540 547 542 548 541 549 544 551 564 570 552 558 567 573 569 574 545 550 565 571 180 8.797 1.68 221 11.164 1.92 200 10.494 1.15 204 10.415 2.44 182 9.169 1.05 227 11.483 1.36 180 7.979 .50 218 9.633 1.56 183 8.390 120 5.320 .69 .54 191 10.534 123 7.109 .68 .46 186 10.907 . .53 118 7.373 .58 192 10.518 119 5.847 .60 .37 186 9.590 109 5.100 .32 .48 188 4.583 197 15.773 .76 .02 180 9.875 232 12.899 .39 .31 195 10.233 193 10.179 .57 .13 184 10.616 207 11.779 .68 .02 180 8.411 99 4.880 .26 .24 187 9.311 .48 203 3.609 ' .03 1 81 1.80 1 00 1 rt7 COJl CQ 55 51 38 38 35 35 33 25 24 98 CMA 005297 VINYL CHLORIDE CONCENTRATION DATA ------------------------------------ Worker Job Classification Code PLANT I Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA Dicer II Operator Dicer II< Bagger t 1 ' Dicer II Blender Operator f 11 f 1-12 3/18/75 557 1 . 562 1-15 3/19/75. 566 1 572 1-17 3/19/75 568 1 575 199 11.270 196 11.392 185 8.268 203 9.635 186 10.620 193 10.862 .26 .13 .38 .02 .13 .14 20 IQ 14 . * I ! i 99 CMA 005298 VINYL CHLORIDE CONCENTRATION DATA PLANT J Job Classification Worker Code Date & Sample Time Volume VCL Shift Number (min) (liters) (ppm) TWA "C" Calender Operator Plastisol. Blender Plastisol Blender "C" Hill Operator ' "W- Ttwer Worker' * "A" Blender Operator "B" Blender Operator "A" Banbury Operator "C" Banbury Operator Color Weighman "B" Feed Mill Operator "B* Mix Mill Operator J-6 J-9 J-10 J-5 J-l J-2 J-ll J-7 0-3 0-4 0-8 0-12 4/9/75 1 4/10/75 1 4/10/75 1 4/9/75 1 4/9/75 1 4/9/75 1 4/10/75 1 4/10/75 1 4/9/75 1 '4/9/75 1 4/10/75 1 4/10/75 I 581 587 590 596 591 597 580 586 576 582 577 584 592 598 588 594 578 583 574 585 5d9 595 593 599 180 8.224 .02 180 8.786 .02 135 11.629 175 11.423 .02 .02 184 10.086 176 9.822 .02 .02 180 9.268 <.01 180 9.202 .01 180 9.196 <.01 191 11.339 <.01 180 7.374 <.01 180 8.142 <.01 186 8.808 <.01 174 8.347 <.01 180 8.483 <.01 182 8.815 N.O. 180 9.837 <.01 180 8.830 <.01 180 9.428 .<.01 180 10.032 <.01 195 10.207 <.01 167 8.383 <.01 196 10.099 .01 164 8.834 <.01 0? 02 n9 01 <m < 01 *m <.01 01 < 01 < 01 * 100 j. ANALYSIS OF DATA General Based on the Code of Federal Regulations, Title 29, Chapter XVII, Part 1910.93q, effective date 1 April 1975, an action level of 0.5 ppm averaged over an 8-hour day, a permissible exposure limit of 1 ppm averaged over an 8-hour day, and a ceiling of 5 ppm averaged over any period not exceeding 15 minutes is prescribed for employees exposed to vinyl chloride. This survey has shown that exposures above the action level of 0.5 ppm, permissible exposure limit of 1 ppm (TWA), and ceiling of 5 ppm exist at times in the work areas of vinyl chloride manufacturing plants. Detec tion methods employed in this survey comply with the f!I0SH Vinyl Chloride report, P&CAM #127.3 Data obtained from surveys conducted at three vinyl chloride manufac turing plants shows that employees classified as Loaders, Operators, and Laboratory Technicians perform in areas where concentrations of vinyl chloride above the TWA of 1 nrm and ceiling of 5 ppm were detected. Plant A The concentration ranges of vinyl chloride detected on the charcoal tubes exposed at Plant A are listed below. / 1 Classification Concentration Range _______ (ppm) Laboratory Technicians Operators Loaders Instrument Hen Shift Supervisors Area (plant) Area (loading) 0.04 to 4.36 0.13 to 2.45 0.17 to 1.89 0.02 to 0.25 0.03 to 0.21 0.56 to 5.89 <0.01 to 0.01 3Ibid 101 CMA 005300 During sample handling and operations, laboratory technicians wore cartridge-type respirators. Loaders are required to wear air line breath ing respirators during all loading and transfer operations. All other per sonnel are required to wear cartridge-type respirators where vinyl chloride concentrations in the work area are above 25 ppm. No loading operations were conducted during the time that the survey was performed. The 4.36 ppm concentration shown above for Laboratory Technicians was experienced by a laboratory technician who was out In the plant collecting vinyl chloride (liquid) samples from sampling ports during a 1-1/2-hour period, and who was exposed to vinyl chloride funes. The 2.45 ppm concentration shown for Operators resulted from the 108minute period during which one operator was exposed to vinyl chloride while out In the plant performing routine inspection and control operations. Another operator, on a previous day, was exposed to 1.57 ppm of vinyl chlo ride while performing similar duties. Operators working in the control room were not exposed to concentrations of vinyl chloride above the action level during the same time periods. During the three continuous 1-1/2-hour periods that the loader was ex posed to concentrations of vinyl chloride above the action level, he was performing routine duties in the storage area, loading area, and pipe line transfer area. Another operator, on a previous day, was not exposed to concentrations of vinyl chloride above the action level during four con tinuous 1-1/2-hour periods while performing similar duties. Stationary area samples taken near four Individual viqyl chloride re actors indicated the presence of vinyl chloride concentrations of 0.55, 2.19, 4.03, and 1.10 ppm for four consecutive 1-1/2-hour periods on one 102 day, and 1.28, 5.89, 2.03, and 1.33 ppm for four consecutive 1-1/2-hour periods the next day. Plant B The concentration ranges of vinyl chloride detected on the charcoal tubes exposed at Plant B are listed below. Classification Concentration Range Loaders Operators Laboratory Technicians Pipe Fitters Chromatographers Area (loading) Area (plant) 3.00 to 84.77 0.01 to 3.46 0.03 to 0.88 0.01 to 0.33 0.02 to 0.12 0.09 to 1.22 0.05 to 0.38 During sample handling operations, laboratory technicians wore car tridge-type respirators. Loaders wore air line breathing respirators during transfer operations. 011 vinyl chloride plant personnel have been Issued one or more types of respirators and are required to wear a respira tor when the potential for exposure to vinyl chloride exists and when, opening and closing valves. Mo loading operations were conducted during the time that the survey was performed. During four consecutive 1-1/2-hour periods, the third-shift loader was exposed to vinyl chloride concentrations of 84.77, 3.00, 7.13, and 11.59 ppm while performing transfer operations and other routine duties in the vinyl chloride storage and tank car loading area. The transfer line valves that were operated were located beneath the storage spheres. On a previous day, during three separate 1-hour and two separate 1-1/2- hour consecutive time periods, a first-shift loader was exposed to vinyl chloride concentrations of 10.80, 28.52, 13.12, 19.32, and 14.63 ppm while 103 \ CMA 005302 performing similar operations. Stationary samples taken beneath the tank car loader's shack gave readings of 1.22, 0.09, 0.20, 0.36, and 0.31 ppm for the same time periods. This indicates that vinyl chloride was leaking to the atmosphere during the operation of the transfer valves beneath the vinyl chloride storage spheres. During the first 1-1/2-hour sample taken on a first-shift tower operator, a 3.46 ppm exposure level was detected, and a 3.0 ppm exposure level was de- I tected for a third-shift compressor house operator for the first 1-1/2-hour I sample.1 The remaining three 1-1/2*hour samples taken for both operators were below 1.0 ppm. In the sampling period during which the tower operator was exposed to 3.46 ppm of vinyl chloride, a sampling valve was noted to be leak ing. The valve was replaced by personnel wearing hose line respirators and gloves. In the sampling period during which the compressor house operator was exposed to 3.0 ppm of vinyl chloride, two vinyl chloride samples were collected in sampling containers. During the sampling operation and when the operator was reading gauges in the rundown area, and operating shipment line valves, the operator was wearing a cartridge-type respirator. A first-shift laboratory technician was exposed to 0.55 and 0.88 ppm of vinyl chloride during the second and third 1-1/2-hour sampling periods. During the second period, he received two vinyl chloride samples for testing. In the third period, he was testing the air at the hatch of a light ends recovery tank during the disposal of vinyl chloride. The technician was { wearing a cartridge-type respirator during this operation. Plant C The concentration range of vinyl chloride detected on the charcoal tubes exposed at Plant C are listed following. 104 Classification Loaders Operators Chromatographers Shift Supervisors Pipe Fitters Laboratory Technicians Area (plant) Concentration Range _______ M_______ 0.06 to 21.8 O.Ofi to 18.2 0.02 to 1.01 0.25 to 0.55 0.16 to 0.41 0.07 to 0.11 0.59 to 7.06 During sample handling operations, laboratory technicians wore cartridge- type respirators and gloves. Loaders wore air line breathing respirators and gloves during tank car loading and transfer operations. All plant personnel have been issued respiratory protection devices and are required to wear them when working In areas or performing specific operations where the exposure to vinyl chloride is higher than, or could be higher than, the permissible OSHA limit. Disposable or washable coveralls and gloves are required for person- nel performing tasks which could expose them to vinyl chloride. During tank car loading operations, three loaders working as second- shift team were exposed to vinyl chloride. One loader was exposed to 17.6, 0.06, 21.8, and 0.23 ppm of vinyl chloride. The second loader was exposed to 6.19, 0.34, 20.1, and 1.13 ppm of vinyl chloride, and the third loader was exposed to 1.74, 0.09, 14.6, and 0.37 ppm of vinyl chloride In four con secutive 1-1/2-hour sampling periods. During the first sampling period, the loaders were hooking up a tank car for loading. During the second sampling period, they were In the loading house. Tank car sampling operations were performed In the third sampling period. Tank car filling operations were checked several times during the fourth sampling oerlod. Air line respira tors, gloves, and washable coveralls were worn during the above sampling and tank car filling operations. On the previous day, two first-shift loaders working as a team on tank car filling and sampling operations were exposed to 0.67, 2.31, 0.35, and 0.38 ppm of vinyl chloride for the first 105 . CMA 005304 loader and 1.50, 0.98, 0.34, and 0.99 ppm for the second loader. During the first sampling period, the tank car was sampled prior to filling. The tank car was hooked up for filling. Filling was started during the third sampling period and continued through the fourth sampling period. The loaders spent most of the third and fourth sampling periods in the loading house during the tank car filling operations. Air line respirators, washable coveralls, and gloves were worn when working near or on the tank car. Two vinyl chloride operators In the East plant were exposed to higherthan-permissible levels of vinyl chloride on different days. A first-shift operator was exposed to 18.2, 0.61, 0.37, and 0.88 ppm, and a second-shift operator was exposed to 6.24, 0.22, 0.21, and 1.95 ppm of vinyl chloride during four consecutive 1-1/2-hour sampling periods. The first- and secondshift operators made a check of the scrubbers during the first and fourth sampling periods. Hose line respirators were worn by both operators during checkout of the scrubbers. Four 1-1/2-hour stationary area samples taken at the scrubbers read 7.06, 1.60, 1.61, and 2.73 ppm and are an apparent source of vinyl chloride fumes. A second-shift purification operator in the North plant was exposed to 3.35, 0.20, 0.25, and 0.10 ppm of vinyl chloride during four consecutive 1-1/2-hour sampling periods. During the first sampling period, a rundown check of the valves, gauges, and equipment was performed. During the check- i out, a cartridge-type respirator was worn. Four consecutive 1-1/2-hour stationary area samples tckn at the vinyl chloride reflux pimps near the North plant purification train read 0.59, 1.15, 5.19, and 3.17 ppm. A gas chromatograph operator was exposed to 0.03, 1.01, 0.06, and 0.04 ppm of vinyl chloride during four consecutive 1-1/2-hour sampling periods. 106 CMA 005305 During the second sampling period, the operator was analyzing ethylene di chloride, ethyl chloride, and trichloroethane samples in the gas laboratory and was not handling any vinyl chloride. No respirator was worn during the analysis operations. Plants D, E, F, G, H, I. and J The'concentration ranges of vinyl chloride detected on the charcoal I tubes exposed in the polyvinyl chloride processing plants were below the OSHA-prescribed action level except for Plant I. The concentration ranges I for the polyvinyl chloride plants surveyed are listed below. Classlfication Concentration Range (ppm) Plant D Plant E Plant F Plant G Plant H Plant I Plant J <.01 to .02 <.01 to .37 N.O. to .06 N.D. <.01 to .13 .02 to 2.44 <.01 to .02 The potential for exposure to vinyl chloride is considerably higher at Plant I than for the other polyvinyl chloride processing plants surveyed. In addition to the polyvinyl chloride processing facilities. Plant I has two on-site polyvinyl chloride resin manufacturing plants. The potential for vinyl chloride in the atmosphere and work areas appears to be considerably higher for resin manufacturing plants than for the vinyl chloride manufacI turlng or polyvinyl chloride processing industries. During the second day of the survey at Plant I, u rupture disc failed In one of the polymerization reactors and vented vinyl chloride through a vent pipe in the roof of the polymerization plant. The polymerization plants are located on opposite sides of the 51 calender and diced compound plant where concentrations of 107 CMA 005306 I vinyl chloride above the 1 ppm TWA levels were detected on that day. Vinyl chloride levels ranging from 0.24 to 0.68 ppm were detected on samples col lected the previous day. and 0.02 to 0.76 ppm on the day following the failure of the rLpture disc. Housekeeping, equipment operation, compounding opera tions, and safety programs are good at this plant. The higher amounts of vinyl chloride detected in the processing plant wens undoubtedly pulled into the processing plant from the adjacent resin plants via the ventilating system. The elimination of entrained vinyl chloride in the polyvinyl chloride resin and compounds supplied to the polyvinyl chloride processing companies by the resin and compound manufacturing companies will eliminate the occur rence of vinyl chloride fumes above the OSHA-prescrlbed action level in the polyvinyl chloride plants that do not have nearby resin manufacturing facilities. * CMA 005307 . -i CONCLUSIONS The following conclusions were reached during the in-depth surveys performed at three vinyl chloride manufacturing plants and seven polyvinyl chloride processing plants. Despite sincere efforts on the part of all companies contacted to reduce the level of vinyl chloride to which their employees are exposed, vinyl chloride concentrations above the OSHA-prescribed 1-ppm TWA and 5-ppm, 15-minute ceiling still exist In some vinyl chloride manufacturing, storage, and loading areas. Loading personnel must wear respirators and protective clothing designed to handle the high concentrations of vinyl chloride that occur during vinyl chloride transfer and loading operations. Instruments that detect the presence of vinyl chloride in the work ,, areas are necessary to prevent personnel from being unaware of ex posure to vinyl chloride. All personnel working In vinyl chloride plants must be supplied with and trained In the use of respirator devices that are designed to handle the concentrations of vinyl chloride that can occur in the work area. e Personnel handling vinyl chloride should wear gloves and disposable \ or washable outer garments In addition to a suitable respirator. _. 1_ All of the vinyl chloride manufacturing plants contacted for the vinyl chloride acr"ev produced vinyl chloride in outdoor facilities. The enclosed control rooms, laboratories, and eating and smoking rooms should be maintained under positive pressure with the air free from chemical contaminants to prevent these areas from being contaminated by outside air. 103 CMA 005308 I'O / gr V There have been many recent changes made in equipment seals and designs, improved ventilation, revised operating procedures, and Improved industrial hygiene and safety practices. These changes for improvement, plus the use of closed-loop sampling and loading systems have had and will continue to have considerable effect in reducing the concentration of vinyl chloride In vinyl chloride manufacturing plants. See Description of Vinyl Chloride Monomer Plants Surveyed (Plants A, B, and C). # The|reduction of entrained vinyl chloride in the polyvinyl chloride i resins and compounds used by the polyvinyl chloride processing Inj dustry has reduced the exposure of the workers in this industry below the OSHA-prescribed action level of 0.5 ppm. * 110 .1 S' /. ...* CMA 005309 CMA 005310