Document MG4zYpOkE0eeXqkJEo3DkbDaL

;'j3X!'];j aB'i] 'J13 _hJJ &]v|J'y (t) MEDICAL ANO H A L T H RESOURCES DIVISION R T Cr.*nq, Ph D P E, ", \ *"_> * . ' `_Ntp3;,7*0[**`*f?T6 h;d3;i..i. dv j'i'it inO -jich'ioh -I I l-'V 3 ^ *j ; `JiSl^FsT P O 3Csx $ I <5 c ^ 5en OitfQQ CA 02(33 B, H. Gambrill, President CHINA GULF PLA5TICS CORPORATION Post Office Box 22144 Taipei, Taiwan 105 Republic of China Dear Bryan: Enclosed are two copies of the report on the follow-up industrial ' hygiene survey of China Gulf Plastics Corporation's Toufen Plant and Taoyuan Plant conducted in ^ovembei^>1981`' ............. .. Occupational vinyl chloride exposure at CGPC has been reduced to around 2 ppm for reactor cleaners and other process area workers at Polymer Plant. Mercury exposure was in compliance with Chinese and the United States standards. Future industrial hygiene emphasis should be placed in reducing employee exposures to solvent vapors and dusts, and in controlling fugitive VCM emissions. Please let me know if there are any questions regarding this report. Best Regards, RTC/mim Enclosures cc: C. R. Grimes J. R. Strausser ' Runion/Davis Microfilm (2) 4 Ro^t l. Cheng. / * OIL COOPQflAT'O >g (0011) CUSAROSS 00048 0034 0001 FOLLOW-UP INDUSTRIAL HYGIENE SURVEY OF CHINA GULF PLASTICS CORPORATION NOVEMBER 1981 By R. T. CHENG, Ph.D., P.E. Regional Industrial Hygiene Director Gulf Science & Technology Company (0011) CUSAROSS 00049 00 34 0002 I. SUMMARY A follow-up industrial hygiene survey of China Gulf Plastics Corporation's manufacturing facilities at the Toufen General Plant and Taoyuan Branch Plant was conducted in November, 1981. The purpose of the survey was to evaluate the progress of CGPC's Industrial Hygiene Program since the October 1979 audit. Primary attention was given to the review and evaluation of occupational ex posures to vinyl chloride monomer (VCM), solvent vapors, and dusts of lead and chromium. Other occupational health hazards surveyed included workers' exposure to mercury vapor and noise. Following is a summary of the findings of this survey: A. As indicated by the VCM exposure results, CGPC was already in compliance with the Chinese 10 ppm VCM exposure standard, and was very close in meeting the U.S. 1 ppm VCM exposure standard. B. VCM odor was not detected in the normal work areas of the Polymer Plant and Monomer Plant during the entire duration of this survey. This indicates that acute exposures to high concentration (2000 ppm and above) have been virtually eliminated. This was an encouraging finding in view of a recent toxicological report that inhaling a single high dose of VCM (5000 ppm for 1 hr) may cause pulmonary tumors in laboratory mice. C. Time-weighted average VCM exposure for Polymer Plant workers was between 200 ppm to 500 ppm before 1974. During this survey. Polymer Plant reactor cleaners and process area workers were exposed to an average of 1.5 ppm to 2 ppm of VCM during their 8-hour workshift. Workers in the Polymer Plant control room were exposed to less than 1 ppm of VCM as time-weighted average concentration. D. In-plant VCM air pollution was cased by the dispersion and wind carry-over of stack effluents and other VCM emissions from the polymerization processes. VCM air pollution has been reduced since the last survey. Results of this survey indicate that office workers and engineers at the Engineering & Development Building, and "non-VCM" workers at the Fabrication Complex were exposed to less than 0.3 ppm of VCM due to in-plant VCM air pollution problem. CUSAROSS 00050 1 (0011) 0034 0003 E. Occupational mercury vapor exposures have been brought under control by the various engineering and work-practice measures implemented. Chlor-Alkali Plant workers, including the flake caustic soda machine operators, showed mercury vapor exposures within the Chinese and the U.S. permissible limit. F. Solvent vapor exposures for the #5 surface treating machine operators have been reduced after installation of the new local exhaust system. Toluene and MEK exposures for Toufen Printing Shop workers were excessive when the local exhaust systems for the printers were out of service. Solvent exposures for workers at the Engraving Room, the Catalyst Plant, and the Taoyuan Printing Shop were all well within the permissible limits. G. Compounding ingredients mixing operators were overexposed to lead dust. Excessive exposures to PVC resin dust were indicated for several workers handling and transporting bags of PVC resin. H. Dust and cyclohexanone exposures by flocking machine operators were determined to be excessive. I. Occupational noise exposures exceeded permissible limit for all mixing roll operators and most of the winder operators of #1, #3, #5, #7, #8 and #15 calenders. The new #17 calender emitted much less noise than the older calenders. J. CGPC's respiratory protection program was judged to be substandard. Preliminary results of this survey have been reported to Mr. B. H. Gambrill, CGPC President, and Mr. S.K. Yeh, CGPC Vice President. A closing conference was held at the Toufen Plant with Mr. K. Yu, Vice President and General Plant Manager, with most of the plant management personnel also attending. The author wishes to thank Messrs. B. H. Gambrill, S. K. Yeh, K. Yu, and other members of CGPC management for their courtesies during this visit. Gratitude to Mr. Ed Lu and his staff, and especially to Mr. J. Y. Huang, for their help in carrying out the survey work. CUSAROSS 0005] 2 (0011) 0034 0034 II. RECOMMENDATIONS A. Conduct additional air sampling to confirm, but hopefully to refute, the findings of high vinyl chloride concentrations inside the Plating Shop Engraving Room, B. Control fugitive VCM emissions by replacing some of the older and worn-out process equipment with double mechanical seal pumps, packless valves, or other proven no-leak or low-leak equipment. C. A specially designed lid should be manufactured to fit the automatic water-jet cleaning machine and the reactor top manhole, thus reducing VCM emission during the time of water-jet cleaning. D. Intensify the implementation of "search and secure" program. Encourage the reporting of VCM odor for speedy leak control . E. Local exhaust ventilation system similar to that installed on the #5 surface treating machine should be installed on the #4 and #6 surface treating machines. F. Local exhaust ventilation systems at the Toufen Printing Shop should be repaired and further improved to assure printer operators are exposed to acceptable levels of MEK and toluene. G. Removable and cleanable ink catchers installed beneath the ink troughs can prevent the spilled ink from plugging the slots of the existing down-draft local exhaust system. H. The flock addition chamber on top of the flocking machine should be enclosed. Improved local exhaust ventilation should be provided at the front end of the flocking machine to reduce flock dust and cyclohexanone exposures. I. Ventilation on the third floor of the New Extrusion Plant should be improved by installing local exhaust hoods on the three supermixers and at the compounding ingredients preparation area. J. Hygiene conditions at Taoyuan Plant's pigment packing room should be improved and a local exhaust hood installed for the weighing and handling of hazardous dusty materials. CUSAROSS 00052 3 (0011) 0034 0005 K. Noise reduction by engineering control measures is preferred. Whan that is technically and economically infeasible, wearing of hearing protectors should be made mandatory by those operators whose time-weighted noise exposures approached or exceeded 100% of the permissible exposure limit. L. Noise emission from #3103 PVC resin pelleting and vibrating machine can be significantly reduced by insulating the thin metal cabin shell with a layer of PVC leather, and operate this machine with cabin door closed. M. CGPC should initiate an audiometric testing program for all new employees and for employees working in high noise areas. N. CGPC should strengthen its respiratory protection program and initiate a respirator qualitative fit test program. O. It would be most beneficial to CGPC if Mr. Ed Lu or Mr. J. Y. Huang could attend NIOSH Courses on "Industrial Hygiene Laboratory Quality Control" and/or "Industrial Hygiene Chemistry". CUSAROSS 00053 (OOU) 0034 4 0006 III. VINYL CHLORIDE EXPOSURE A. Vinyl Chloride Health Effects Early occupational health studies on vinyl chloride often reported acute toxic effects (dizziness, headaches, nausea, etc.). In January 1974, the B. F. Goodrich Chemical Company reported to the United States National Institute of Occupational Safety and Health (NIOSH) that several of its employees had died from angiosarcoma of the liver (a rare form of cancer) and that those deaths may have been related to occupational exposures to vinyl chloride. Experimental toxicological studies in later years con firmed that vinyl chloride is a carcinogen, mutagen and teratogen. To date, more than 50 cases of liver angiosarcoma have been reported or confirmed worldwide among workers with a history of exposure to vinyl chloride. Most, but not all, of these cases have been among workers involved directly in PVC production. The latency period following the onset of occupational exposure is estimated to be about 13 to 30 years. While the focus of attention has been on liver cancer, it should be noted that a number of industrial studies suggest that the risk of developing other cancers, particularly lung and brain cancer, as well as liver dysfunction and other disorders, also has been related to vinyl chloride exposure. B. Vinyl Chloride Exposure Standards In the 1960's, the permissible exposure limit for vinyl chloride was 500 ppm in the United States and other countries. Available air monitoring data indicates that typical occupational exposures in PVC manufacturing plants were in the range of 100 to 400 ppm as 8-hour time-weighted average exposure. In October 1974, after confirmation of carcinogenic effects, the U.S. Occupational Safety and Health Administration (0SHA) set the following permissible exposure limits for occupational vinyl chloride exposure: 1. No employee may be exposed to vinyl chloride at concentrations greater than 1 ppm averaged over any 8-hour period. 2. No employee may be exposed to vinyl chloride at concentrations greater than 5 ppm averaged over any period not exceeding 15 minutes. CUSAROSS 00054 5 (0011) 00 34 0007 3. No employee may be exposed to vinyl chloride by direct contact with liquid vinyl chloride. In the Republic of China, the standard for vinyl chloride exposure remained at 500 ppm until 1981 when the Chinese Labor Department set a health standard limiting 8-hour time-weighted average vinyl chloride exposure at 10 ppm. C. Historical Review of VCM Exposure and Control Actions at CGPC 1. Initial Industrial Hygiene Survey, February 1974 During this initial industrial hygiene survey, VCM concentrations above 10,000 ppm were sometimes encountered at Toufen's Polymeriza tion Plant during reactor purging time. The odor of VCM (odor threshold^2,000 ppm) could be detected very readily inside the Polymer Plant and sometimes at the Monomer Plant. It was established that the time-weighted average VCM exposure for Polymer Plant workers was in excess of 200 ppm, probably between 200 ppm and 500 ppm. Control measures recommended and implemented included prolonged and improved vacuum-assisted recovery of unreacted monomer, and cover-up of the top manhole during reactor bleeding and air purging time, with the reactor exhausted through a vent pipeline leading to the outdoors. 2. Follow-up Industrial Hygiene Survey, August 1976 Odor of VCM was still detectable at the Polymer Plant and sometimes at the Monomer Plant. Long-term air sampling results suggest that the time-weighted average VCM exposure for Polymer Plant workers was in excess of 50 ppm. A three-step VCM control program was recommended. Step one was to reduce workplace VCM concentration below odor threshold level. Step two was to achieve Canada's VCM exposure standard of 10 ppm. A "Search and Secure" team was formed to search for fugitive VCM leaks and secure the leaks through maintenance and repair measures. A Goodrich solvent spraying technique was adopted to reduce PVC scale formation, resulting in the reduction of reactor cleaning time. CUSAROSS 00055 6 (0011) 0034 ooos 3. Follow-up Industrial Hygiene Survey, November 1977 VCM odor was essentially eliminated from the Polymer Plant except during the short time (two to three minutes) of PVC scale flushing down from the dome of the reactor. It was estimated that a reactor cleaner's typical eight-hour time-weighted average VCM exposure was somewhere between 15 ppm to 50 ppm. Other workers at Polymer Plant were exposed to less than 10 ppm of average VCM concentration. Reduction of VCM exposure was achieved through implementation of the "Search and Secure" program. Portable local exhaust hoods were used at the reactor bottom manholes to move VCM-contamined air to the outdoors during air purging time. Adoptation of one of the automatic reactor cleaning processes was recommended to eliminate routine reactor cleaning. 4. Follow-Up Industrial Hygiene Survey, October 1979 Odor of VCM was rarely detected in the Polymer Plant. Time-weighted average VCM exposure for reactor cleaners was 18 ppm. Other Polymer Plant workers were mostly exposed to 2 or 3 ppm of vinyl chloride. Further reduction of VCM exposure was achieved through increase in VCM recovery from the reactor by prolonged vacuuming. Automatic water-jet cleaner was used to do the initial cleaning, thus reducing the manual cleaning time. Results of November 1981 VCM Exposure Survey Instruments employed during this survey included an H-NU Photoionization Analyzer for measurement of workplace airborne VCM concentrations, and 3M Brand Organic Vapor Monitors for long-term personnel air sampling. Grab air samples were collected with direct-reading VCM chemical detector tubes. 1. VCM Odor Survey The odor of vinyl chloride was not detectable on each of the three floors of the Polymer Plant and at the Monomer Plant complex. Results of this odor survey suggest that acute exposures to 2000 ppm or more of vinyl chloride have been eliminated. This is very important because CUSAROSS 00056 7 (0011) 0034 0009 laboratory studies have shown that inhaling a single high dose of VCM (5,000 ppm for one hour) caused pulmonary tumors in mice. Workplace VCM Concentrations The Model PI 101 Photoionization Analyzer by H-NU Systems, Inc. is capable of detecting VCM at roughly 0.2 ppm concentration. Survey with H-NU showed less than 0.5 ppm of VCM on the first floor, approxi mately 0.5 ppm on the second floor, and averaged 3 ppm on the third floor of the Polymer Plant. No VCM was detected inside the Control Room and Office Room on the third floor of this building. During automatic water-jet cleaning of the reactors, VCM concentrations around the opened top manhole varied between 10 to 30 ppm. This could be the most significant source of VCM emission on the third floor. It is recommended that the top manhole should be covered as tight as possible to prevent vapor escape during the jet cleaning time. A specially designed lid should be manufactured to fit the automatic water-jet machine and the reactor top manhole. VCM concentrations inside the reactor (measured at the bottom manhole) during the reactor manual cleaning time varied between 3 to 10 ppm, and averaged about 5 ppm. Two years ago, VCM concentration during reactor cleaning time was 20 to 30 ppm. This reduction of VCM con centration was achieved through increase of the vacuuming time before opening the reactor for cleaning; and through prolonging the duration of automatic water-jet cleaning before allowing personnel entry for manual cleaning. Leaks of VCM were detected at several valves and flanges on the third floor of the Polymer Plant. Some of these process equipment were old and worn out. They should be replaced or repaired to reduce fugitive emission. At the Monomer Plant, leaks were detected at level gauges and flanges of VCM tanks 337A, 337B and 3383. The tree transfer pumps near tank 336A and 336B leaked badly. Due to these fugitive VCM leaks, an average VCM concentration of 1 ppm was detected at the tank storage CUSAROSS 00057 8 (0011) 003^ 0010 building. VCM concentrations elsewhere at the Monomer Plant were either non-detectable or less than 0.2 ppm. At the PVC Resin Drying Plant, airborne VCM concentrations ranged from non-detectable inside the Control Room to less than 0.5 ppm downstairs near the bagging process. At the Pilot Plant, the three large wall fans provided good general ventilation. No VCM was detected inside this building. 3. Time-Weighted Average VCM Exposure Samples for assessing long-term time-weighted average VCM exposure were collected by attaching 3M Brand Organic Vapor Monitors on workers' lapels during their 8-hour workshift. Table I summarizes results of VCM exposures for workers at the Polymer Plant. Data in Table I were arranged in groups according to workers' job functions. For plant foreman, engineer, instrument operator and office worker who stayed mostly inside the control room and office area of the Polymer Plant, their VCM exposures ranged from 0.28 ppm to 0.87 ppm. Among workers in this group, the instrument operators (control board watcher) and the office worker showed the least exposures. The two plant fore men, who had to go out to the process area frequently, showed the highest exposures. The job function of a reactor charger is to charge the reactor with vinyl chloride monomer, water and catalyst. Compared to plant foreman, the reactor chargers spend more time outside in the process area. Therefore, their VCM exposures were higher, ranging from 0.76 ppm to 1.5 ppm. The job function of a reactor discharger is to drain the reactor of PVC resin after completion of the polymerization reaction, opening the top and bottom manholes, and setting up the automatic water-jet cleaning device. The three reactor dischargers monitored showed time-weighted average VCM exposures of 2.6 ppm, 3.4 ppm, and 24 ppm, respectively. The 24 ppm VCM concentration for Mr. 0. K. Hsu was unusually high, and might be due to some untypical work pattern. CUSAROSS 00058 9 (0011) 0034 0011 TABLE I OCCUPATIONAL TIME-WEIGHTED AVERAGE VCM EXPOSURES FOR WORKERS AT POLYMERIZATION PLANT CGPC TOUFEN PLANT NOVEMBER, 1981 EMPLOYEE IDENTIFICATION Peng, T.S. Shieh, M.S. Huang, H.L. Yeh, C.C. Peng, S.S. Huang, J.Y. 55130 56113 6038S 69011 55131 59110 JOB AT POLYMER PLANT Foreman Instrument Oper. Office Worker Engineer Foreman Instrument Oper. SAMPLING DURATION 420 min 418 min 364 min 363 min 365 min 364 min VCM PPM 0.87 0.28 0.31 0.41 0.75 0.38 Fu, T.S. Huang, W.K. Chang, S.Y. Lin, H.S'. 56129 67279 58116 56110 Reactor Charger Reactor Charger Reactor Charger Reactor Charger 418 min 409 min 363 min 355 min 0.77 0.76 1 .5 1 .1 Chen, C.Y. Tsung, C.S. Hsu, O.K. 59113 58115 54120 Reactor Discharger Reactor Discharger Reactor Discharger 411 min 356 min 357 min 2.6 3.4 24 Chio, Y.G. Lai, C.S, Li, J.H. Li, S.Y. Hsu, H.C. Chen, C.S. Koo, W.S. Chen, C.W. Chio, Y.G. Li, J.H. Tan, J.G. Li, S.Y. Koo, W.S. 67266 64275 66123 67277 65387 64114 69212 64114 67266 66123 66124 67277 69212 Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner Reactor Cleaner 415 min 414 min 414 min 413 min 413 min 412 min 411 min 362 min 361 min 361 min 361 min 359 min 355 min 1 .8 1 .5 2.7 1.5 0.95 1.9 1.8 1.4 1.3 1.3 5.5 1 .4 0.44 (0011) CUSAROSS 00059 0034. 0012 Reactor cleaners working during the dayshift usually clean six reactors manually. For the thirteen reactor cleaners monitored during this survey, their time-weighted VCM exposures ranged from 0.44 to 5.5 ppm, with an arithmetic mean exposure of 1.8 ppm for the group. Overall, results in Table I indicate that control room workers at the Polymer Plant were exposed to less than 1 ppm of time-weighted average VCM concentration, while process area workers at the Polymer Plant were typically exposed to 1.5 to 2 ppm of VCM. Table II sunmarizes occupational time-weighted average VCM exposures for workers at the Pilot Plant, Monomer Plant, and PVC Resin Drying Plant. Results indicate that all exposures were less than 1 ppm. In conclusion, occupational vinyl chloride exposures at China Gulf Plastics Corporation were well within the Chinese 10 ppm standard, and very close indeed in meeting the U.S. OSHA 1 ppm standard. CGPC workers and management should be congratulated in achieving this excellent record in VCM exposure reduction. CGPC has begun to replace the old and smaller reactors with new reactors of modern design. Occupational VCM exposure will be reduced further in the near future. In view of the recent finding that a single high dose of VCM can produce cancer growth on laboratory animals, the significance of odor threshold of VCM (2,000 ppm) should be emphasized to all vinyl chloride workers. No one should be exposed to odor-detectable concentration of VCM for even a short duration. Workers should be encouraged to report vinyl chloride odor so that major leaks and emission sources can be secured. Workers should be able to refuse working in an area where VCM odor is detectable except during an emergency and when proper respiratory protection is provided. 4. Vinyl Chloride Air Pollution Problem Due to wind carry-over, the air in areas downwind from the Polymer Plant could be contaminated by VCM vapors emitted from stacks and other sources at the Polymer Plant and the PVC Drying Plant. On November 11, 1981, the wind was blowing from the north and northeast CUSAROSS 00060 11 (0011) 3334 0013 TABLE II OCCUPATIONAL TIME-WEIGHTED AVERAGE VCM EXPOSURES FOR PILOT PLANT, MONOMER PLANT AND PVC DRYING PLANT WORKERS CGPC TOUFEN PLANT NOVEMBER, 1981 WORKER IDENTIFICATION PILOT PLANT WORKERS Wu, K.L. Lin, W.C. Chang, S.S. Shih, H.C. Lin, M.Y. Chen, S.Y. 69020 59196 66140 65278 59198 67237 JOB Engineer Operator Operator Operator Operator Operator SAMPLE DURATION VCM PPM 402 min 401 min 401 min 400 min 402 min 401 min < 0.036 Lost 0.28 0.80 0.35 0.073 MONOMER PLANT WORKERS Wen, F.M. Fan, W.C. Chen, C.W. 60291 69109 55120 Instrument Oper. VCM Unloading Instrument Oper. 343 min 336 min 335 min 0.086 0.81 0.066 PVC DRYING PLANT Fong, Y.T. 65318 Instrument Oper. 347 min < 0.041 CUSAROSS 00061 (0011) 0334 0014 12 TABLE III AMBIENT VCM CONCENTRATIONS AT VARIOUS LOCATIONS OF CGPC FACILITIES NOVEMBER, 1931 SAMPLING LOCATION SAMPLE DATE NUMBER OF SAMPLES RELATIVE TO POLYMER PLANT RANGE OF VCM CONCENTRATIC Printing Shop Catalyst Plant Leather Plant Plating Shop Printing Shop Leather Plant Plating Shop 11/11/81 11/11/81 11/17/81 11/18/81 11/20/81 11/24/81 11/25/81 15 3 14 3 12 12 3 Downwind far Downwind near Downwind Upwind Downwind far Downwind Upwind ND* - 0.081 0.16 - 0.54 ND - 0.17 9.6 - 14 ** ND ND - 0.064 1 .2 - 4.8 ** TAOYUAN Plant 11/13/81 4 None ND ND* - Not detected, detection limit approximately 0.03 ppm of VCM. ** - Further investigation should be conducted to confirm or reject these consistent high readings of VCM concentrations at the Printing Shop. CUSAROSS 00062 0016 003^ (0011) 13 to south and southwest direction at moderately high wind speed (*v 4 to 5 meter/second). Measurements with H-NU Photoionization Analyzer and with VCM direct-reading detector tubes showed the following ambient VCM concentrations: MEASUREMENT LOCATION________ RELATIVE TO POLYMER PLANT VCM ppm New Extrusion Plant Raw Material Warehouse LC #2 Station #17 and #19 Calender Engineering Building #7 and #8 Calender Upwind Crosswind Downwind Downwind Downwind Downwind Not detected 0.1 0.1 - 0.2 0.2 - 0.3 0.2 - 0.3 0.1 - 0.2 The above results indicate that employees working downwind from the Polymer Plant were exposed to very small amounts of VCM due to in-plant air pollution problems. Further evidence of the minor in-plant VCM air pollution was obtained by analyzing VCM concentrations in organic vapor samples collected from workers at facilities other than the Polymer Plant and the PVC Drying Plant. As shown in Table III, long-term average VCM exposures for the three Catalyst Plant workers varied from 0.16 ppm to 0.54 ppm. The Catalyst Plant is located downwind near the Polymer Plant and PVC Resin Drying Plant. Further distances downwind from the sources of VCM emissions are the Leather Plant and the Printing Shop where workers were exposed to VCM concentrations ranging from non-detectable to 0.17 ppm. Four personal organic vapor air samples collected from Taoyuan's Printing Plant workers were analyzed for VCM contents. The results, all non-detectable, were listed at the bottom of Table III. Taoyuan Plant is simply a PVC fabrication facility. For some unknown reasons, the samples collected from the three Plating Shop workers consistently showed high VCM concentrations. Plating Shop is located upwind from the Polymer Plant. Therefore, it was unlikely that VCM emissions from the Polymer Plant would affect workers at the Plating Shop. Unless there was an unexpected VCM emission source near or inside the Plating Shop, the detected VCM might be unrelated to airborne VCM concentrations, but due to chemical (OOll) 0034 14 CUSAROSS 00063 interferences of the sampling media by the electroplating and engraving operations. CGPC Industrial Hygiene Department should conduct surveys (with VCM detector tubes) either to locate the unexpected VCM emission sources, or to confirm the non-existence of VCM inside the Plating Shoe. C__o_n__tro.l. of Fuwcitive .V..C.M-- E--m--is sions Further reduction of VCM exposures at China Gulf Plastics Corporation can be achieved through control of fugitive emissions. Fugitive emissions include emissions that occur from valve stems, flanges, pressure relief valves, pumps, compressors, and agitator seals, from loading and unloading of monomer, and from sampling for laboratory analysis. These fugitive or unaccountable losses represent the most significant sources of emissions in PVC plants. Rapid detection of a leak so that it can be quickly repaired is an important facet of reducing fugitive losses. Large VCM leaks can be visually detected by the frosting which occurs at the discharge because of the cooling effect of gas expansion. Large leaks can also be detected by the odor of vinyl chloride. Small leaks can be detected by several methods. A fixed multipoint gas chromatograph, analyzer and recorder system can be used to periodically sample the VCM content in the ambient plant air at as many as 100 points within a plant. The recorder can be fitted with an alarm to alert the operator of high VCM levels. When a high level is detected in a specific section of the plant, the exact location of the leak can be determined by the use of a portable hydrocarbon analyzer. Many of the U.S. PVC manu facturers have installed continuous monitoring instrument systems in recent years. Included in the Appendix of this report are two types of these monitoring systems used by U.S. PVC manufacturers. CGPC's Industrial Hygiene and Safety Department has one set of Century Organic Vapor Analyzers. The Company has recently purchased a second set of Century Analyzers to be kept and used by Polymer Plant operators. Consequently, VCM leaks can be monitored on a more frequent basis, and repairs can be carried out soon after leak detection. CUSAROSS 00064 15 (0011) 0034 0017 Detailed record of "search and secure" program should be maintained. The conditions surrounding each leak should be recorded. A periodic evaluation of these records serves to pinpoint recurring problem areas. Single mechanical seals are presently used on most vinyl chloride pumps. The seal faces on single seal pumps are lubricated by a slight outward flow of VCM between the stationary and rotary faces. This flow can be eliminated by using a double mechanical seal pump in which a seal fluid such as glycerin and water, or ethylene dichloride is circulated and maintained,, at a pressure greater than exists in the pump, between the two seals. When leakage occurs, a small amount of seal fluid can leak into the pump, but VCM cannot leak out of the pump. The initial capital cost of double mechanical seal pump is greater, however, the frequency of maintenance is much less. Mr. C. S. Lee, Superintendent of the Polymer Plant requested information on valves, the types of valves that will leak the least. The U.S. Environ mental Protection Agency have contracted studies undertaken to provide fugitive emission factors for various chemical process equipment. It is their recommendation that packless valves provide best control for vapor leaks. Packless valves are commercially available. There are two main types, differing chiefly in the means of isolating the valve stem from the process stream. In the diaphragm type, closure of a flexible diaphragm to vary flow rate is accomplished by means of a plunger attached to the stem. For high temperature and high pressure service, a sealed metal bellows type of packless valve is a more suitable choice. A U.S. PVC manufacturer have replaced all ball valves with eccentric plug valves manufactured by FWI, Inc. (Tulsa, Oklahoma). Plant engineering and maintenance personnel believed that historical data indicates that FWI valves are the best for VCM service at that plant. CUSAROSS 00065 ooie (0011) 033** 16 IV. MERCURY EXPOSURE During the initial Industrial Hygiene Survey of February 1974, mercury vapor concentration at the central aisle of the Electrolysis Room was 0.25 mg/m^. Since that time, many engineering control measures have been adopted to reduce the workplace mercury concentration. These include opening up all windows on both sides of the main floor to promote natural air circulation between indoor and outdoor air; removing most of the walls on all four sides of the basement to achieve the same general air circulation effect; installation of a local exhaustion ventilation system along the central aisle of the mercury cells; and, most importantly, enclosure of the head boxes and end boxes of the mercury cells to prevent mercury vapor evaporation. Dramatic reduction of workplace mercury concentrations has been accomplished since 1974. Results of surveys indicated that the mercury vapor concentration along the central aisle of the cell room was reduced to 0,05 mg/m^ during 1976 and 1977; and further reduced to about 0.02 mg/m^ during 1979. This dramatic reduction was achieved despite the fact that many more new mercury cells were installed inside the cell room during the past years. The only remaining problem area was the flake caustic soda machine operation in the basement of the cell room, where, due to bad ventilation and mercury spill, the airborne vapor concen tration remained above 0.15 mg/m^. Additional engineering controls have been installed since 1979. The flake caustic soda machine was moved out from the basement of the cell room to an open area along the Electrolysis Building. After the move, the mercury concentration at the new flake caustic soda machine was reduced to around 0.03 ppm. Other engi neering and workpractice controls completed after 1979 included improvement of the brine purification system, total enclosure of the top box and end box of each mercury cell, and exhausting the top and end boxes to the brine tank to recover mercury. CGPC also employed a vacuum pump system to recover spilled mercury. Various analytical instrumentation have been employed to conduct mercury vapor surveys at China Gulf Plastics Corporation. CGPC Industrial Hygiene Department have a set of JW Model MV-2 Mercury Sniffer and a Perkin-Elmer Model 50 Mercury Analyzer. A Jerome Gold-Film Mercury Vapor Analyzer and Personal Dosimeter System have been used to confirm the readings obtained by CGPC's instruments. CUSAROSS 00066 17 (0011) 0034 0019 Bendix Brand mercury vapor detector tubes were used to collect grab air samples at point sources* During the 1981 Industrial Hygiene Survey, personal mercury vapor dosimeters by 3M Company were employed to measure long-term time-weighted average exposures to mercury vapor. Unfortunately, the 3M dosimeters showed corrosion due to chemical interference or other unknown reasons (e.g., storage in the refrigerator with other materials and samples, breakage of the sealing aluminum foil, etc.). Consequently, no valid results of the 3M Mercury Dosimetry Survey have been obtained. Table IV presents results of three most recent surveys of mercury vapor concen trations in the Chlor-Alkali Plant. The mercury vapor monitoring positions are indicated on a map of the Electrolysis Room as shown in Figure 1. CGPC Industrial Hygiene Department conducts such mercury vapor surveys roughly once every two months. Review of the survey results indicate that China Gulf Plastics Corpora tion was meeting the occupational mercury vapor exposure standard of 0.05 mg/m^. For temporary, short-duration exposure to high mercury vapor concentrations such as during maintenance and clean-up of the mercury cells, proper type of respirator should be worn by the workers. Substantial protection can be provided by a disposable type of mask by 3M Company (3M Brand Mercury Vapor Respirator #8707). 3M has a sales office in Taipei. CUSAROSS 00067 18 (oon) 00 34 0020 FIXED SAMPLING POINTS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 TABLE IV WORKPLACE MERCURY VAPOR CONCENTRATIONS IN CHLOR-ALKALI PLANT, TOUFEN, CGPC LOCATION Office NW of #35 Cell S. of #35 Cell S. of #29 & #31 Cells S. of #23 & #25 Cells S. of #17 Cell S. of #11 & #13 Cells S. of #5 Cell E. end of South Cells E. end, Center of Building NE of #3 & #5 Cells N. of #7 & #9 Cells Center of #9 L #10 Cells N. of #17 Cells N. of #21 & #23 Cells Center of #29 & #30 Cells SW of #36 Cell Booth N. of #36 Cell N. side of #30 & #32 Cells N. side cf #24 & #25 Cells N. of #18 Cell N. of #12 l #14 Cell N. of #6 Cell E. of North Cel 1 s Caustic Soda Machine* Laboratory Rest Room MERCURY VAPOR CONCENTRATION (n Test 1 Test 2 Test 3 0.03 0.005 0.005 0.01 0.015 0.02 0.02 0.03 0.015 0.06 0.025 0.06 0.045 0.065 0.05 0.03 0.01 ND** 0.005 0.02 ND ND ND 0.01 0.005 -- 0.005 0.01 0.015 0.015 0.005 0.025 0.03 0.045 0.04 0.045 0.03 0.015 0.03 0.02 0.02 0.02 0.03 0.015 0.008 ND 0.005 0.013 0.01 0.005 0.005 0.015 0.005 0.02 0.005 0.01 0.025 0.02 0.03 0.01 0.01 0.05 0.04 5 0.055 0.065 0.03 0.03 0.03 0.015 0.04 0.02 0.015 0.01 ND 0.01 0.01 ND 0.005 0.005 0.CC5 0.01 0.07 0.005 0.01 * Two additional measurements with MV-2 Mercury Sniffer showed mercury vapor concentrations of 0.015 and 0.025 mg/rri3 at the new flake soda machine operation. ** ND: Mot detected, concentration less than 0.005 mg/m3. CUSAROSS 00068 19 (0011) 0034. 0021 FIGURE 1 - M ercury Vapor M o n ito rin g P o in ts a t C h lo r - A lk a li Plan f/or/4 ReCCrJmg Vejk NORTH N* C> Concrete cetomn T.--t VN>*4 K K u. fc. CO N CD Ol fc M O' VoooO ttoo o oc, <to p u [ill \ <3 iKJ s *1 tr> N& fcl '4i> M it-J a a rj Oik cij> C-I vi co> p a r. ^ ^ > -i g,^1" Fan i x > i U( <0 w u O'*- CD > i ^a $ i/J N ? > <0 v-t J to Ct- Soul!/) flccOrdmg J>esh, Fla He - Soda Ma.cA//}{:s ^ ^/ On (0011) 0034. # 22 V. SOLVENT EXPOSURE Bulk quantities of industrial solvents were consumed at the Flexible Products Fabrication Complex of Toufen Plant and at Taoyuan Plant's printing shop. The solvents were used mainly as surface treating agents and as an ink carrying vehicle in the manufacturing of PVC leathers, films and fabrics. The predominant solvents used by CGPC were methyl ethyl ketone (NEK) and toluene, each consumed at approximately 20 tons per month. Other solvents consumed in large quantities were methanol, methyl isobutyl ketone (MIBK), cyclohexanone, ethyl acetate, and dimethyl formamide. Benzene was not used by CGPC as a solvent in the fabrication processes. However, industrial grade toluene could contain benzene as impurity. A. Surface Treating Machines During the industrial hygiene survey of 1974, none of the surface treating machines in the Leather Plant was ventilated with local exhaust hood. The general ventilation condition inside the Leather Plant was grossly insuffi cient for diluting solvent vapors to an acceptable level. Total solvent vapor concentrations, as measured with a Century Organic Vapor Analyzer around the surface treating machines, varied between 200 to 1,000 ppm. The plant was operated at less than 50% capacity at that time, but workers complained about headache, nausea, and poor appetite due to solvent overexposures. Working conditions at the surface treating machines have been greatly improved since the 1974 survey. Installation of local exhaust ventilation hoods at the surface treating machines was responsible for the decrease in occupational solvent vapor exposures. Total organic vapor concentra tions at the surface treating machines have been reduced to mostly below 200 ppm. A high capacity side-draft exhaust hood with air curtain was newly installed at the #5 surface treating machine. Total organic vapor concentration was 300 ppm in front of the ink trough of the #5 machine before the new exhaust system was in operation, and reduced to 50 ppm at the same location after the new exhaust system was in operation. Several long-term breathing zone air samples were collected from surface treating machine operators with 3M Brand organic vapor monitors. Table V summarizes the air sampling results. The current permissible exposure limits CUSAROSS 00070 21 (0011) 0034. 0023 TABLE V TIME-WEIGHTED EXPOSURES TO MEK, TOLUENE, MIBK AND BENZENE BY CGPC SURFACE TREATING MACHINE EMPLOYEE: I.D. MEK ppm #2 Surface Treating Machine Operators TOLUENE PPm , . MIBK ppm Lin, Y.L. Chen, M.L. Hsu, Y.P. 61233 61239 67208 27 6.7 2.9 5.7 1.8 0.77 6.0 1 .8 0.77 #3 Surface Treating Machine Operators Shieh, Y.L. Ko, A.W. 61277 70145 16 16 6.2 1.5 4.9 1.5 #4 Surface Treating Machine Operators Tsai, C.S. Wu, Y.S. Huang, L.Y. * Lin, R.H. * Li, H.C. Chen, T.F. 60222 69117 60177 59179 61396 70127 8.4 0.83 4.1 240 130 6.7 3.2 0.54 1 .8 43 35 2.4 0.85 0.15 0.52 20 16 0.85 #5 Surface Treating Machine Operators Liu, P.S. * Peng, W.C. Li, K.J. Chang, J.G. Wu, F.Y. Peng, F.A. Wu, Y.S. 67249 60209 58260 64126 61211 64189 59160 0.86 660 3.8 0.98 58 1.8 < 0.05 1.2 248 1.6 1 .1 13 0.51 26 0.2 60 0.16 0.18 <0.05 < 0.05 0.3 #6 Surface Treating Machine Operators Yeo, M.S. Lin, J.S. Pang, J.T. * Tien, C.Y. * Chieo, S.H, * Huang, C.L. 61418 61302 64198 61328 60355 61350 3.7 20 84 150 180 140 1.7 0.48 81 2.6 26 8.5 45 10 51 11 43 9.6 Shop Foreman Liu, S.L. * Lo, F.S. 58213 56153 5.3 2.1 0.6 96 56 10 BENZENE PPHL < 0.05 < 0.05 <0.05 < 0.05 < 0.05 0.1 < 0.05 < 0.05 0.06 < 0.05 < 0.05 0.09 0.17 0.1 0.1 < 0.05 < 0.05 < 0.05 0.08 <0.05 0.12 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 employee was overexposed to total solvent vapors. 22 (0011) CUSAROSS 00071 0034. 0024 for individual solvent is 200 ppm for MEK, 100 ppm for toluene, 100 ppm for MIBK, and 10 ppm for benzene. Because the health effects of these solvents are additive, results in Table V indicate that a few operators had exceeded the combined permissible exposure limit for the group of solvents. It appears that the existing ventilation system is adequate for controlling solvent exposures at the #2 and #3 surface treating machines, while the #4 and ~6 surface treating machines should be improved further to reduce employee solvent exposure. Among the seven operators of the #5 surface treating machine, only one person, Mr. W. C. Peng, received unusually high exposure. Because his MEK, toluene and MIBK exposures were so out of line from others having the same job, it is likely that his high exposures were caused by an unusual occurence. For example, a drop of solvent might have been accidentally splashed onto the air sampling monitor. The new local exhaust ventilation system for the #5 surface treating machine was determined to be effective. Similar ventilation systems should be installed at the #4 and 6 machines to reduce occupational solvent exposure at those two machines. B. Toufen Printing Shop There are three printers inside the Toufen printing shop. A 4-color printer, a 5-color printer, and a 6-color printer. Solvent vapors, mainly those of MEK and toluene, evaporate from the ink troughs and from the treavelling PVC fabrics. The printing shop was surveyed on November 11, 1981 and again on November 20, 1981. The results of the two surveys were drastically different. All three printers were in operation on November 11. The shop was very clean and the odor of solvent vapors was barely detectable. Measurements with an H-NU Model PI 101 photoionization analyzer showed that the total solvent vapor concentrations ranged from 20 ppm to 50 ppm. Measurements with MEK and toluene chemical detector tubes showed MEK and toluene concentrations in the 10 to 30 ppm area. On November 20, 1981, only two printers (the 5-color and the 6-color) were in operation. The down-draft local exhaust systems under the two printers were disassembled for repair and cleaning. Solvent odors were readily CUSAROSS 00072 23 (0011) 0034. 0025 detectable.' Measurement with H-Nll analyzer showed total organic vapor concentrations ranged from 200 to 1,000 ppm. Measurement with MEK and toluene detector tubes confirmed the high vapor concentrations. Long-term breathing zone air samples were collected from Toufen printing shop workers on November 11 and again on November 20 with 3M Brand Organic Vapor Monitors. Table VI presents results of this personal exposure survey. On November 11. printing shop workers had time-weighted average exposures to MEK, toluene, MIBK and benzene all well within the permissible limits of these solvents. On November 20, 1981, however, seven printing shop workers showed excessive toluene exposures and very high MEK exposures. Results of these surveys proved the importance of the local exhaust systems for reducing solvent vapor concentrations at the printing shop. The air exhaust slots should be free of ink, grease and other contaminations to achieve top performance. Perhaps a removable and cleanable ink catcher installed just beneath the ink trough could prevent the spilled ink from plugging the exhaust slots of the down-draft ventilation system. C. Taoyuan Printing Shop Taoyuan Plant's printing shop has one 6-color printer located inside a rather spacious building. Housekeeping inside this shop was excellent. The floor around the printer was free of ink stains. Although the same type of down-draft local exhaust hood as those used at Toufen printing shop was used for this 6-color printer, workers at Taoyuan plant made an extra effort to prevent spilled ink from plugging the exhaust slots by placing layers of paper on top of the ventilation hood to catch the spilled ink. Measurements of ventilation adequacy with smoke tubes showed satis factory air flow pattern for controlling solvent vapors under the travell ing PVC fabric and from the ink troughs. Table VII presents results of personal time-weighted average exposures to solvent vapors by Taoyuan printing shop workers. All four workers had exposures well within the permissible limits. D, Engraving Room MEK and toluene were used inside the engraving room of the Plating Shop CUSAROSS 00073 24 (0011) 0034. 0( TABLE VI TIME-WEIGHTED EXPOSURES TO MEK, TOLUENE, MIBK AND BENZENE BY CGPC TOUFEN PRINTING SHOP WORKERS EMPLOYEE I .C. SURVEY ON NOV,. 11, 1981 Chen, Y.L. Chen, L.F. Lin, J.C.* Cheng, J.M. Liu, M.Y. Chen, T.C. Tzeng, C.Y. Koo, W.C. Tang, S.L. Tan, C.S. Chio, W.G. Chen, L.C. Kao, M.S. Peng, W.S. Chio, C.S. 65348 56138 60220 68198 70140 61380 56014 65125 66157 67132 65359 70139 67136 56134 56238 MEK TOLUENE PPm ppm 16 26 7.5 17 0.42 34 15 36 37 20 21 19 41 28 42 14 18 8,9 15 0.3 28 12 19 20 14 14 10 23 17 26 MIBK EEHL. BENZENE _p_pni 0.24 0.72 0.24 0.24 0.06 0.40 0.70 0.20 0.27 0.19 0.73 0.23 4.7 1.1 6.3 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 SURVEY ON NOV,. 20, 1981 t Ko, C.F. Lin, W.T. t Hsu, V.T. t Liao, W.H. t Tsai, F.L. t Tong, S.L. Li, B.B. Liu, S.Y. Wu, J.Y. Lin, J.C.* t Fu, J.B. t Chuang, M.L. 67202 70124 64125 57132 65335 67278 65139 67204 67133 60220 57131 68112 120 4.9 230 190 140 120 49 15 12 2.0 130 120 643 1 .7 <0.05 5.4 0.3 0.09 464 1.9 1.2 683 1.8 1 .0 664 2.0 0.87 641 1.4 0.77 22 3.0 <0.05 12 1.7 <0.05 10 1 .4 <0.05 1.8 0.1 0.05 663 2.0 0.84 660 1.6 0.76 NOTES: * On November 11, 1981, all three printers were in full operation. On November 20, 1981, only the 5 color and 6 color printers were in operation. Mr. J. C. Lin is ink preparation room worker. Permissible Exposure Limits: MEK: 200 ppm. Toluene: 100 ppm, MIBK: 100 ppm and Benzene: 10 ppm Employee overexposed to solvent vapors. 25 (0011) CUSAROSS 00074 0034. 0027 TABLE VII OCCUPATIONAL TIME-WEIGHTED AVERAGE MEK AND TOLUENE EXPOSURES FOR TAOYUAN PRINTING SHOP WORKERS CGPC TAOYUAN PLANT November 13, 1981 WORKER IDENTIFICATION Lo, C.C. 61908 U, C.H. 65973 Le, M.C. 66919 Feng, D.M. 68840 JOB Printer Foreman Foreman Printer MEK ppm 0.10 0.71 1 .2 0.93 TOLUENE PPm MIBK ppm 2.6 < 0.03 4.4 < 0.03 7.9 < 0.03 8.3 < 0.03 BENZENE PPm_ <0.05 < 0.05 < 0.05 < 0.05 CUSAROSS 00075 (0011) 0034. 0028 26 to wash and degrease rollers of the printing machines. Workers of the engraving room mentioned solvent vapor inhalation due to working with solvents without adequate ventilation (wall fans cannot be used in order to preserve air. cleanliness). Long-term personal samples were collected with 3M Organic Vapor Monitors to determine their solvent exposures. Table VIII presents results of samples collected on two working days. All three engraving room workers showed toluene and MEK exposures well within the permissible exposure limits. E. Catalyst Plant MEK and MIBK are used in the catalyst plant. Table IX presents results of long-term personal samples collected from catalyst plant workers for solvent vapor analysis. Results indicate occupational exposures to MEK and MIBK were at minimal or non-detectable levels. F. Flocking Machine A new flocking machine was installed inside the building where the old floor tile plant was located. Cyclohexanone was used as the solvent in the preparation of glue and surface treating solution. The air around and above the flocking machine was odorous and caused minor throat irritations. Cyclohexanone concentrations were 20 to 50 ppm at the front end of the machine and approximately 5 ppm at the tail end of the machine. The highest cyclohexanone concentration was at the fabric entrance to the baking oven where 100 to 150 ppm was detected. Inside the office area, cyclohexanone concentration was 15 to 20 ppm. Cyclohexanone concentration at 25 ppm was not objectionable to most human subjects during a 5 minute exposure. Throat irritation was the most marked effect at 50 ppm. Cyclohexanone at 190 ppm caused liver and kidney injury to rabbits upon prolonged exposure. In 1978, NI0SH recommended a timeweighted exposure limit of 25 ppm. The new threshold limit value (TLV) recormiended by the American Conference of Governmental Industrial Hygienist has been reduced from 50 ppm to 25 ppm for occupational cyclohexanone exposure. Based on survey results, it is likely that workers operating the flocking machine could have cyclohexanone exposures exceeding the new TLV of 25 ppm, CUSAROSS 00076 27 (0011) 0034. 0029 TABLE VIII OCCUPATIONAL TIME-WEIGHTED AVERAGE EXPOSURES TO MEK AMD TOLUENE BY ENGRAVING ROOM OPERATORS CGPC TOUFEN OPPERATION NOVEMBER 25, 1931 WORKER IDENTIFICATION Cheng, Y.D. Huang, A.C. Liao, C.M. 66113 64290 66115 Cheng, Y.D. Huang, A.C. Liao, C.M. 66113 64290 66115 DATE 11/18/81 11/18/81 11/18/81 11/25/81 11/25/81 11/25/81 SAMPLE DURATION 480 min 480 min 480 min 429 min 428 min 427 min MEK ppm 1 .2 1 .1 0.54 0.36 0.36 0.37 TOLUENE ppm 8.7 8.4 9.2 1 .2 1 .3 1 .7 CUSAROSS 00077 28 (0011) 0034, 0030 TABLE IX OCCUPATIONAL TIME-WEIGHTED AVERAGE EXPOSURES TO MEK AND MIBK BY CATALYST PLANT OPERATORS CGPC TOUFEN OPERATION NOVEMBER 11, 1581 WORKER IDENTIFICATION Wang, H.S. Tsung, W.J. Woo, W.F. 55134 55136 69144 SAMPLE DURATION MEK BE MIBK mL 366 min 366 min 365 min < 0.05 < 0.05 < 0.05 < 0.05 0.05 < 0.05 CUSAROSS 00078 29 (OOII) 0034. 0031 but still within the current Chinese standard of 100 ppm. It is recoirmended that the existing local exhaust ventilation system should be improved. Major emphasis should be placed on the picking up of cyclohexanone vapors escaped from the baking oven, and for controlling cyclohexanone and flock fiber emissions from the flock addition chamber. Ventilation at the front end of the machine can be improved by installing a side-draft local exhaust system similar to that newly installed for the #5 surface treating machine. No improvement is required at the tail end of the machine. CUSAROSS 00079 30 (0011) 0034. 0032 VI. DUST EXPOSURE CGPC Toufen Plant now has two compounding ingredients mixing rooms, one for the Old Extrusion Plant and one for New Extrusion Plant. The compounding ingredients include plasticizers, stabilizers, lubricants, fillers, pigments, etc. The stabilizers are added to avoid the disintegration of the PVC resin and to prevent discoloration. At CGPC, powders of lead, cadmium and barium stearates are used as stabilizers. Many types of dyes and pigments are mixed with PVC resins to impart color to products. It is not unusual to find very toxic compounds in dyes and pigments. Inorganic pigments include salts and oxides of lead (particularly lead chromate), molybdenum, chromium, antimony and titanium. CGPC reported the monthly consump tion of two pigments, molybdate orange P-380 and chrome yellow GL at 5.1 ton and 6.1 ton, respectively. In the United States, the current permissible occupational exposure limits are: 0.05 mg/m3 for chromate compounds, 0.05 mg/m3 for lead, 0.5 mg/m3 for barium, and 0.05 mg/m3 for cadmium. The U.S. National Institute for Occupational Safety and Health (NIOSH) has declared that certain forms of hexavalent chromium, including lead chromate, have been found to cause increased respiratory cancer mortality among workers. NIOSH recommends that exposure to those carcinogenic hexavalent chromium be not greater than one microgram per cubic meter of air (1 ug/m3). Long-term breathing zone air samples were collected from workers at dusty opera tions. These samples were analyzed for total particulate concentration, and for lead, barium, cadmium and chromium concentrations. Table X summarizes the results of occupational time-weighted average exposures. Excessive exposures to cadmium and chromium occurred only to the compounding ingredients mixing operator of the Old Extrusion Plant. Excessive lead exposures occurred to all compounding ingredients mixing operators, and to a few operators of the blenders and mixers at Toufen. Quite a few samples showed massive exposure to total dust. One sample showed 210 mg/m3 of total dust (mainly PVC resin dust). Most of those huge dust exposures occurred not as a result of massive airborne dust concentration in the general workplace, but due to close contact of the workers to the dust sources-. For example, many workers were involved in carrying CUSAROSS 00080 31 (0011) 0034. 0033 TABLE X OCCUPATIONAL EXPOSURES TO AIRBORNE CONCENTRATIONS OF BARIUM, CADMIUM, CHROMIUM, LEAD AND TOTAL DUST CHINA GULF PLASTICS CORPORATION NOVEMBER, 1981 EMPLOYEE NAME JOB AND LOCATION BARIUM mg/m3 COMPOUNDING INGREDIENTS MIXING Shu, L.C. Shu, L.C. Tsung, G.H. Tsung, G.H. Old Compounding Plant-Nov. 11 Old Compounding Plant-Nov. 27 New Compounding Plant-Nov. 11 New Compounding Plant-Nov. 27 .24 .0016 .0015 .0072 BLENDER & MIXING OPERATORS Liao, R.S. Koo, L.C. Chen, C.Y. Chang, S.C Huang, S.C Yeh, Y.Y. Tzeng, T.T Lu, C.C. Lin, S.M. Old Extrusion Plant Blender Old Extrusion Plant Blender Old Extrusion Plant Mixer Old Extrusion Plant Blender Old Extrusion Plant Blender Old Extrusion Plant Blender Blender, #4 Calendar Blender, #2 Calendar Blender, if8 Calendar .0100 .0010 .0011 .0064 .021 .0008 .0041 .0023 < .0004 OTHER DUSTY OPERATIONS Chen, C.F. Wu, C.P. Flocking Machine Operator PVC Leather Buffing Machine < .0004 .0025 TAOYUAN PLANT Ko, Y.G. Chang, C.C. Wu, S.L. Lu, T.S. Pigment Packing Room Supermixer, #9 Operator Ribbon Mixer, #15 Calendar Bambury, #11 Calendar < .0004 < .0004 < .0004 < .0004 CADMIUM mg/ .16 * < .0028 < .0022 < .0028 .0052 < .0026 < .0026 .021 .0078 < .0023 < .0037 < .0026 < .0026 < .0025 .0025 < .0023 < .0023 < .0024 < .0004 CHROMIUM mg/m3 .34 * < .0046 < .0037 < .0046 < .0044 < .0043 .012 .0044 .0062 < .0039 < .0062 < .0043 < .0043 .018 .0099 < .0038 < .0038 < .0040 < .0040 LEAD mg/m3 3.4 0.13* 0.48* 0.56* 0.17 * 0.017 0.030 0.24 * 0.25 * 0.011 0.025 < .0043 < .0043 .0066 .025 < .0038 < .0038 < .0040 < .0040 TOTAL DUST mg/nr 20 * 1 .4 3.8 3.9 2.0 0.16 0.30 210* 14 * 0.51 97 * 0.59 0.60 61 * 30 * 0.43 7.4 0.14 50 * * Indicates overexposure. Permissible Exposure Limits: Barium: 0.5 mg/m^. Cadmium: 0.05 mg/n)3, Chromium: 0.05 mg/m3, Lead: 0.05 mg/m3, Totaj^^ist (nuisance): 10 mg/rn^ (0011) 0034. CUSAROSS 00081 CM CO 0034