Document 6bnkY3mLR2KZmgkDmyY6Oew79

Biochemical Research Laboratory The Dow Chemical Company VAPOR EXPOSURES TO VINYL CHLORIDE AND VINYLIDENE CHLORIDE ENCOUNTERED BY REACTOR AND STILL OPERATORS, 'Polymer #1 and #2, saran production. BUILDING 262 File: T64.4-2-2 Date: March 10, 1965 By: E. J. Schneider Signed Checked Pursuant carbon analyzer has been used to continuously monitor vapor con-, centrations of vinyl chloride and vinylidene chloride In operator's work areas of the Saran Production Plant for several years. The equipment has provided supervision with a daily record of the vapor concentrations of vlnyl/vlnylldene chloride encountered by the operators as well as an Indication of leaking equipment. Until recently, however, there has not been available a satisfactory method of compiling the data to show the exposure pattern of the operators to vinyl chloride and vinylidene chloride. In the early part of 1962 the Environmental Research Laboratory acquired data processing equipment which could be used in con junction with the electro-conductivity analyzer and the Burroughs digital computer. During the months of January through the middle of June, 1962, and again during the months of January through April, 1963, environmental studies were conducted at the Saran Production Plant using the new data processing equipment. RESTRICTED: for use within The Dow Chemical Company only. R&S 000441 Biochemical Research Laboratory T64.4-2-2 Page 2 ,'r ' " ...^.jPursuan CONCLUSIONS a! Company 1. Reactor operators (kettle men) of the PolJyi4er-;'#I9JsbJbtion do Western District of New York encounter at times high concentrations of vinyl/vlnylldene chloride. Time-weighting the exposures resulted in values in excess of recently proposed safe limits for repeated exposures. oo o -ft. to 2. The high concentrations do not correlate with Increased production but relate more directly to operating techniques and maintenance of equipment. A daily investigation of the cause of the high concentrations over a trial period of time by supervision did produce a satisfactory reduction in the operator's exposure. 3. Time-weighted exposures to vinyl/vlnylidene chloride encountered by reactor operators (kettle men) of the Polymer #2 section and the still operators of both sections were found to be within acceptable levels. 4. Results of physical examinations of the operators conducted by the Medical Research Laboratory at the time of the 1963 environmental survey are to be reported separately. REASONS FOR THE ENVIRONMENTAL STUDY Vinyl chloride and vlnylldene chloride monomers are reacted in the presence of a catalyst to produce saran polymer. Throughout various stages of manufacture, reactor operators Biochemical _______ nfa'ii'0"rat:o ry1cs|J Fur-^nt T64.4-2-2 To Pfoisc'.'Vd Order Page 3 Hess v. Ccn::::, Cjj'j A:c. Sj-A3j7 Coic3::5'i F'j.'ijii, LA SoiTA v. T/g D:.," f'';c,t;:3!V (kettle men) and still operators are subject^tb.^pJqsslbiie^xposures to the two monomers. Because both vinyl chloride and vinylidene chloride are toxic to the liver and kidneys there is a definite R&S 000443 need to evaluate the operator's exposure and to control them to within acceptable limits. The Environmental Research Laboratory began making surveys with portable air sampling equipment in 1950 with subse quent surveys in 1951> 53 and 55- Results of these surveys prompted supervision to install a continuous monitoring system for detecting and recording concentrations of vinyl chloride/vinylldene chloride in the general work areas for the operators. The monitoring system installed consists of an analyzer and recorder located in a separate room outside the main plant with twelve air sampling lines running out from the analyzer to the .operating areas. The analyzer has a combustion furnace to decom pose the halogenated hydrocarbon, scrubbing absorbers to mix water with the free hydrogen chloride and/or chlorine formed by that decomposition and two six-point Dynalog recorders to record the conductivity of the solution formed. Arrangements were made for' the Instrument Systems Research group to be responsible for weekly * * maintenance of the analyzer and for the Environmental Research Laboratory to check the calibration of the analyzer approximately every six months. This has been done since 1958. Oow Chemical Confidential Vst&i?; Produced Parsuani Bilipocchheemmicical T64.4-2-2 Page 4 b o,rat or,y. Cafcast3'Jp3ri;h, LA Smith v. Tin Po'.v Che ;:'C Cor,". >;r,y .-i --1 -<i-vV' ' ' i ' - >-o.r;yi In determining the vapor concentratlons^Bf^ih'yi^ chloride and/or vlnylldene chloride In the general atmosphere with the halogen analyzer it was not possible to record separately the con centrations of each monomer. The analyzer is nonspecific and is able to only analyze for total halogen content. Thus the instru ment was calibrated to report all the results as vinyl chloride. The chronic vapor toxicity of these two materials is about proportional to the number of chlorine atoms in each molecule. After several months of operation, there was definite evidence (as indicated by the daily charts) that for periods of time lasting a few minutes up to several hours, concentrations of vapors recorded as vinyl chloride in excess of 100 ppm (parts per million by volume In air) existed in various work areas. It, however, has been an unrealistic task to attempt to visually and manually Integrate the data in order to time-weight the exposures of the operators so as to evaluate the possible hazard. Early In 1962 the Environmental Research Laboratory acquired semi-portable analog-to-dlgital-recording equipment which would record each conductivity reading along with time in days, hours and minutes. The data recording system consists of R&S 000444 a specially modified Brown recorder, a Datex Encoder and Programer and a Friden paper tape punch. The data are punched in a code and format suitable for direct entry to the Computations Laboratory B-220 digital computer. The computer was programmed to provide summaries of the concentrations of vlnyl/vlnylidene Biochemlca.lwReJ9,eairIcha,,Lta,bQrsi.to,ry To4.4-2-2 ...... Page 5 ".C? * ' chloride as vinyl chloride at the twelve air*. samplingf;;"l'dc:a:tions W33t-;" 0-:st.-isto.`;w Ytrk in terms of average concentrations and percentage of time above various levels for each of the three daily shifts and for the complete day. Weekly and monthly summaries of this information were also obtained. Later, programming provided time-weighted average concentrations and percentage of time above various levels for the operator's exposures. The new data recording equipment was connected to the continuous monitoring system during the months of January-June, 1962, and again during the months of January-April, 1963. Accurate and acceptable data were obtained within these periods. PRESENTATION OF DATA Nine of the twelve air sampling locations were chosen to monitor the concentrations of vlnyl/vinylldene chloride in areas most frequented by the Saran operators. The other three air sampling locations were used for the Soluble Saran section in other parts of the building. Data from these three locations have not been Included in this report. It was not practical to attempt to monitor the peak exposures which the operators can envounter when cleaning valves on the bottom of kettles, changing filter sacks or replacing safeties in lines. The air sampling points do monitor air that the operators breath the major part of the time. Tables I, II and III indicate the locations of the nine sample points and the jj 8 w ooo Biochemical Research Laboratory T64.4-2-2 Page 6 approximate time spent by the Polymer #1 and #2 reactor and still operators in each of the locations. Oqv; Ct'd"-5 to: jri-1 prnduce-i i1 SO '337 33 St* CO -obO. O) r-.'j'iiT-aiay, i-jira };w York Biochemical Research Laboratory T64.4-2-2 Page 7 Table I APPROXIMATE TIME SPENT BY POLYMER #1 KETTLE MEN IN THEIR VARIOUS WORK AREAS, BUILDING 262 Analyzer Sample Point ______ Location Approximate Time Spent in Area 1 Base of slurry tanks, ground floor 12# level (attends compression area and other duties). 7 Control panel and desk area, third 31# floor level (loads kettles, checks charts, etc,). 9 Area of the scales in the Receiver 20# Room, third floor level (filling the receivers with monomers and attending the pumps). 12 Area of the slurry tanks and base 25# of kettles, second floor level (dropping the contents of kettles to the slurry tanks and cleaning the valves at the bottom of kettles). Lunch room. 12# R&S 000447 TOTAL 100# Biochemical Research Laboratory T64.4-2-2 Page 8 Table XI APPROXIMATE TIME SPENT BY POLYMER #2 KETTLE MEN IN THEIR VARIOUS WORK AREAS, BUILDING 262 Analyzer Sample Point- Location Approximate Time Spent in Area 2 Area near #10 scales in the Receiver Room (filling the receivers with monomer). 6$ 4 Area near #13 scales in the Receiver 6$ Room (filling the receivers with monomer and changing the filter sock). 6 Area hear top #4 drier and kettle trap 20$ (dropping the contents of kettles to the drier and cleaning the valves at the bottom of the kettles). 10 Area of operators desk near #24 and #27 kettles (loads kettles, checks charts, etc.). 46$ Lunch room. 12$ Other duties out of the main operating areas. 10$ TOTAL 100$ R&S 000448 cv. :v.-. T Produced Pursuant o,/nu/i Company ;.;SECisUict 0; 'Jew Biochemical Research Laboratory T64.4-2-2 Page 9 Table III APPROXIMATE TIME SPENT BY THE STILL OPERATORS IN THEIR VARIOUS WORK AREAS, BUILDING 262 Analyzer Sample Point Locations Approximate Time Spent in Area 4 Area near #13 scales in the "Polymer 6$ #2 Receiver Room (does some pumping of vinyl chloride). 9 Area of scales in the Polymer #1 Receiver Room (pumping vinyl chloride). 20$ 11 Inside a small analyzer room (checks 6$ the phenol content in samples of monomers). ' 6 Area of #4 drier and kettle trap (attends the control panel for the still). 31$ - Other duties outside. 25$ -- Lunch room. 12$ TOTAL 100$ Or, t; Chpn-. rr.' io Produced Pursuant eu 337 "LrJ"ilJT.*`2.' Wo-t&i* v < ' of Nsvi VciK R&S 000449 R&S 000450 Biochemical Research Laboratory t64.4-2-2 Page 10 In reporting the results of the continuous monitoring system as vinyl chloride the assumption has been made that vinyl chloride exists in the general atmosphere in much higher concen trations than does vinylldene chloride and that it is vinyl chloride which the operators encounter most of the time. Table IV shows the results of air samples collected at a few of the air sampling locations with subsequent analysis by a vapor phase chromotographlc technique. This method of analysis provides a differentiation between the concentrations of vinyl chloride and vlnylidene chloride. Vapor concentrations of vinyl chloride were found to be about six times as great as vinylldene chloride in the general atmosphere. In reporting analyzer data as vinyl chloride it is believed there would not be a hazard to health from vinylldene chloride providing the exposures to vinyl chloride are controlled to within safe levels. C i ; ' Produced Pursuant ; . ' r :.;r < 337 1--1 t.tiTjany at fJavi York R& s 000451 Biochemical Research Laboratory T64.4-2-2 Page 11 Table IV COMPARISON OP THE RATIO OP VINYL CHLORIDE TO VINYLIDENE CHLORIDE GENERALLY EXISTING AT A PEW AIR SAMPLING LOCATIONS, 3/27/63, 9:00 A.M. Air Sampling Location #1 #7 #9 #12 AVERAGE Vapor Concentrations Vinyl Chloride Vlnylldene Chloride ppm Ratio $> ppm Ratio i. 21.0 10.5 6.2 9.8 88 90.5 74 89 3-0 1.1 2.2 1.2 12 9-.5 26 11 85.4 14. 6 1! Pras'iiccd Pursuant 70--337 `A'sitsm L'i^iiicE af fiaw Yont R&S 000452 BmTC6io\4tc.h4li e-2Om-2iOcal ,-Resear,ch. Laboratory Page 12 Summary data from two separate periods' are reported in the environmental study. During the first period from January-June, 1962, an attempt was made to work closely with supervision by reporting each day any existing high vapor concentrations of the previous day as recorded by the analyzer. Prompt attention by supervision in checking the source of con tamination helped to keep the operator's exposures to low levels. Most of the time the high concentrations noted were the result of leaking pumps, valves, compressors and faulty operating techniques. At the time of the second period a year later the exposure data were obtained allowing normal operation of the plant with no attempt made to point out existing high concentra tions. Charts 1-A and 1-B show time-weighted weekly average exposures as vinyl chloride for the three separate shifts and dally average of the three shifts for the reactor operators of the Polymer #1 section. Also Included on the charts are averages of the three shifts over the two separate environmental study periods. There is no significant difference between shifts; however, there is a major difference in the exposures encountered by the operators from one period to the next. When the plant was studied under "normal" operation as shown by chart 1-B the operator's time-weighted exposures increased several fold com pared to those encountered a year earlier as shown by chart 1-A. Singling out a week where the average exposure was comparable to Biochemical Research Laboratory To4.4-2-2 Page 13 * the total three-month period average exposure chart 1-C shows how wide spread the daily exposures were. To obtain time-weighted averages in excess of 100 ppm meant that vapor concentrations as vinyl chloride had to exceed several hundred ppm for extended periods of time. The significance of these high concentrations will be discussed in an addendum to this report. r Prsluced Pursuant ... ; . :;"i 'r,-M . ,, i '1 . . t'..T03,)y L i'LV Wsrcm District of Me<m York R& s 000453 ,r / n W f i z h t c o C. o n c c /v t -a a t m '/v j 10X lOTOTHE INCH 350-5 KCUfFCL ft CSSCA C.O. OJ m u i i S I J J |V \ Biochemical Research Laboratory To4.4-2-2 Page 17 The reason for the wide variation in the operator's exposures between the two environmental surveys was first considered to be due to an increase in production in 1963- This did not prove to be the case. Chart 2 shows the number of batches of Saran produced in the Polymer #1 and #2 sections and it can be seen, except for the month of January, 1963, there was consider able more Saran produced in 1962 than there was in 1963 for comparable months. It was true there was much more Saran produced in the Polymer #1 section than produced in the Polymer #2 section, however, the average exposures as vinyl chloride in 1962 were about equal for both the Polymer #1 and #2 reactor operators regardless of the wide differences in the production of Saran by the two sections (compare charts 1-A and 3-A). All in all, there does not appear to be a direct correlation between operator's vapor exposures and number of batches of Saran produced. 33 Co to ooO c-fnc* 'J 9: 373 M-v VI *sum Q;S*3:t of Sew 'fork -Li / / J.a/ Oh/ V ^ d 1 /5 0 W V]/V R&s 000459 Biochemical Research Laboratory T64.4-2-2 Page 19 Charts 3-Aand 3-B show the time-weighted weekly average exposures as vinyl chloride for the reactor operators (kettle men) of the Polymer #2 section during the two environ mental study periods. Charts 4-A and 4-B show comparable time weighted exposures for the still operators of the Polymer #1 and #2 sections. The irregular pattern of the time-weighted exposures reveals that at times vapor concentrations were high, however, in averaging the exposures over a period of time it can be seen the amounts are well under a recently proposed safe limit of 50 ppm of vinyl chloride for dally repeated exposures.. Exposures for the reactor operators of Polymer #2 did not Increase in 1963 over 1962 whereas the exposures for the reactor operators of Polymer #1 did. Possibly the difference may be due to newer equipment, better room ventilation (larger operating 1 areas), and less chance for faulty operating techniques because of the reduced production. While these are possible reasons for the lesser vapor exposures of the Polymer #2 operators they are by no means known causes of the lesser exposures. 4 4 R&S 000464 Biochemical Research Laboratory T64.4-2-2 Page 24 When the program for the computer was being devised it was thought a valuable interpretation of the data would be obtained if the percentage of time when the concentration of vinyl chloride and/or vinylldene chloride exceeded certain levels was recorded. Provisions were made to determine the percentage of time which the vapor concentrations as vinyl chloride exceeded 25, 50, 100, 200, 250 and 500 ppm. Charts 5, 6 and 7 are plots of the percentage of time the operator's weighted average exposures as vinyl chloride exceeded the Indicated concentrations. This data reveals that all the operator's exposures to high concentrations of vapors are for very short periods of time. Except for the reactor operators of Polymer #1 in 1963, even exposures near the standard 50 ppm vinyl chloride represented no more than 10$ of the operator's exposures. It is not likely that there has been a hazard to health for the reactor operators of Polymer #2 or the still operators from this sequence of vapor exposures. However, if the reactor operators of Polymer #1 are permitted to continue to encounter vapor concentrations as of 1963 where 50$ of the time the concentrations exceeded 50 ppm and 25$ exceeded 100 ppm, a chronic hazard to health might well exist (see addendum to report). Pakts /m l u v /v a iJ o v e : Z PHOUAUH.ITTO Kturrtl A UOCAfllTHwfC CO. 2 CYCUS 3SB-24 nut IN u j.*. PARTS PER P U L U vV ABOVE `V S," PACT'S P i/i-t/v^s Koy> ---------------------- ' ii-- KCUfKl. tiStifl CO. 10cm U.M. Biochemical Research Laboratory To4.4-2-2 Page 28 RECOMMENDATIONS In the interest of reducing the exposure of Polymer #1 kettle men to vapors of vinyl/vinylldene chloride provisions should be made to evaluate all possible sources of exposure. Dally observance of the halogenated hydrocarbon analyzer charts by supervision and operators will greatly aid in detecting leaks at an early stage and prevent exposures to high concentrations of vinyl/vinylldene chloride for extended periods of time. Operators should identify the source of exposure and Indicate on the charts the corrective action taken. Other uses of con-' t tinuous air analyzers have obtained Improved operation and environmental control through strict adherence to this approach. R&S 000468 TV'j 'i 1'* II V- -,..w .1 ,`j Biochemical Research Laboratory To4.4-2-2 Page 29 ADDENDUM Significance of the Exposures to Vinyl Chloride and/or Vinylidene Chloride The' relatively long lapse of time in reporting the results of the environmental surveys conducted in the Saran Plant in 1962 and 1963 has been due to an uncertainty concerning the actual degree of toxicity of vinyl chloride to the human liver and kidneys as a result of repeated exposures to low con centrations . Until quite recently, all published data has Indicated that vinyl chloride is primarily a central nervous system depressant, causing symptoms of dizziness and disorientation with little or no effect on the liver and kidneys. The present published Industrial Hygienic Standard for vinyl chloride is 500 ppm. However, the toxicologists of our own Biochemical Research Laboratory, conducting studies of exposures to vinyl chloride and also to vinylidene chloride, report evidence of liver and kidney damage in animals from both materials. It is their feeling that for regular dally 7-8 hour exposures of humans the peak concentrations of vinyl chloride in the work environ ment should not exceed 100 ppm with a time-weighted average for all exposures not to exceed 50 ppm. Vinylidene chloride proved to be even more toxic to the liver and kidneys,..-than..,vinyl 'f-jCiL.'j-jj [Vsuarst chloride. Recommended limits are that peak.concentrations of ' ' ' ^ ' :L-;837 R&S 000469 Biochemical Research Laboratory T64.4-2-2 Page 30 vinylldene chloride in the work environment should not exceed 50 ppm with a time-weighted average for all exposures not to exceed 25 ppm. Vinylldene chloride is considered to be very similar to carbon tetrachloride in its toxicity. The toxicolo gical studies of vinylldene chloride have not been challenged, however, in 1963 about the time the environmental studies at the Saran Plant were completed, toxicologists at Yale University published the results of other studies of exposures to vinyl chloride on both animals and humans. Their contention was that the alterations in liver morphology observed by our laboratory were within a normal range and were not pathologic in character. They concluded that the Industrial Hygiene Standard for vinyl chloride should not be lowered but should remain at 500 ppm until more studies are conducted to prove differently. Reporting of the results of the environmental surveys has been postponed in hopes that further clarification of the toxicity of vinyl chloride would be forthcoming. That hope was not well founded; consequently, an Interpretation of the results of the environmental surveys is being made at the time in the light of the data available. As stated in the report, the time-weighted exposures as vinyl chloride were compared with Dow-proposed limits for vinyl chloride for the following reasons: 1) Operators in the Saran Plantare actually exposed ^ Lrr.r-IaM's! Maurw! Produced Piirsua.it to a combination of vinyl chloride and Vinylldene chloride. j. r-: tW'j.GG-4337 R&S 000470 Biochemical Research Laboratory T64.4-2-2 Page 31 2) An effect was definitely noted on the liver and kidneys of animals which were exposed to vinyl chloride as was also the case with vinylldene chloride in our laboratory. 3) The environmental study was comprehensive enough to present an accurate account of the operator's average timeweighted exposures. 4) There are several peak exposures to vinyl chloride and/or vinylldene chloride of very high concentrations "super imposed" on a low base encountered by the operators .t The true significance of these exposures is not known but should not be overlooked. --"-su r'ursjcnf . ^^904337 i 0; v* ,, y !r ` " ii; R&S 000471 R&S 000472 Biochemical Research Laboratory t64.4-2-2 Page 32 UNIT INDEX An evaluation of exposures to vinyl/vlnylldene chloride encountered by reactor and still operators of the Polymer #1 and #2 sections of the Saran Production Plant was conducted in January-June, 1962, and January-April, 1963, using a continuous vapor concentration monitoring system. Datex data recording equipment and a digital computer were utilized to conveniently evaluate the results. Time-weighted average exposures to vinyl/ vinylidene chloride indicate a possible chronic hazard to health for the reactor operators (kettle men) of the Polymer #1 section. Improved operating techniques and periodic maintenance of equip ment is need to keep exposures to within acceptable levels. DISTRIBUTION A- T. Look, Plastics Production, 433A Building E. M. Haas, Saran Production, 262 Building R. E. Onan, Saran Production, 262 Building H. H. Gay, M.D., Medical Department, 607 Building R. D. Stewart, M.D., Medical Research, 607 Building A- W. Wilson, Safety Department, 401 Building R. A. Brown, Safety Department, 401 Building EJS/sJl n icsd Pursuant "1 vir)