Document ZnkOwyeNQw4LRYGa81OXXVQ1L

H U Cs &U Ctj AMERICAN INDUSTRIAL HYGIENE ASSOCIATION ~(<D AIMAAP 41(7) 4M 534 (1M0) ^ \/ i4 m 30 C (/> co VOLUME 41 NUMBER 7 JULY, 1980 ^|^.C463 j Extent of industrial exposure to epichlorohydrin, vinyl fluoride. vinyljjromide and ' ........... 469 Identification of biological dusts by elemental analysis jjfp . ii; 473 Design considerations for fume hoods for process plants 485 Determination of sulfur dioxide by adsorption on a solid sorbent followed by ion chromatography analysis ........ ^ ~ , 489 System for routine testing of self-contained and airline breathing equipment 49? Acute exposure of laboratory mice to manganese oxide 501 Evaluation of performance of a beta absorption dust Vj>08? Industrial hygiene evaluation of thermal degradation products from PVC film in meat-wrapping operations .7;. <s2> Thermal degradation products from PVC film in food 523 Some experiences with epoxy resin grouting compounds 525 Comparative lead emissions from conventional and jacketed ammunition 527 Differences in the extent of solvent penetration through natural and nitrile gloves from various manufacturers ` 528 A comparison of four personal sampling methods for the determination of mercury vapor 531 Comparison of methods for determination -J Forwarding and datum Poataga Guarantaad / Amariean Induatrial Hygiana Aaaociation. 475 Wolf Ladgaa Patinaay. Akron. OH 44311 THE DOW CHEMICAL 0-3. WR08LEWSKI, 4803 BLDG. HXOLANDa MI COMPANY TOX. INFO. 43440 An industrial hygiene evaluation is presented concerning experimental thermal degradation products from hot-wire and "cool"-rod cutting of P used in meat-wrapping operations. Room air concentrations of less tha benzene can be maintained by a number of factors, including minimal dil concentrations of degradation products are presented using average va relation of these concentrations to TLV's is given, together with methods listed by ACGIH or OSHA. Room air concentrations for the 12 degr assigned, based on average values per cut, were no greater than concentrations of DOA are not determinable from available data but pre exposure to DOA causes airway hyperreactivity. The cool rod, rather thai industrial hygiene practice, producing no apparent PVC degradation pro DOA are volatilized. Industrial hygiene evaluation of thermal products from PVC film in meat-wrappi WARREN A. COOK' Professor Emeritus, The University of Michigan. Ann Arbor, Ml 48109 R&S 131072 introduction A number of studies have been made of potential hazards to employee health in meat wrapping departments of supermarkets. Most comprehensive are those conducted by the National institute for Occupational Safety and Health (NIOSH) and its organizational predecessor, the Bureau of Occupational Safety and Health, U.S. Department of HEW, over the six years through 1977. An initial report01 concluded that "there appear to be no apparent health hazards presented by PVC film fumes generated in meat wrapping to normal healthy persons employed as meat wrappers." The NIOSH report1"1 at the end of this period includes all known information on hot-wire cutting of PVC packaging film up to that time and a summary of NIOSH health hazard evaluation studies of meat wrappers and cutters. The conclusion after conducting these extensive studies was that "it cannot he determinedfrom these studies whether actual allergic sensitization and resultant bronchial asthma occurs from exposure to these contaminants." It was noted that "hot wire cutting of PVC meal wrappingfilms and thermal activation ofprice labels can release irritant substances into the meat wrapping work environment;" but that "breathing zone concentrations of the irritant substances emitted are low when compared to established occupational health exposure standards." Much of the information in the NIOSH report'21 has been published in two papers, one on environmental exposure and toxicology1*1 and the companion paper on clinical studies.141 In this latter, more recent paper, the conclusion quoted in the preceding paragraph was again stated. A small number of degradation products on heating PVC film samples to the hot-wire temperature of 200-300 C in a 'Present address: 713 Emory Drive, Chapel Hill, NC 27514. micro furnace were identified by NIOSH,1"* but in order to determine just what substances the meat wrapping operators were exposed to, there was a need for identification of all degradation products of significance from hot-wire film cutting and a determination of the amount of each substance produced. i This basic information has been provided through a research project that is the subject of a paper151 in this issue of AIHAJ. application of research data on thermal degradation products An application of data developed in this research project15* is the evaluation of exposures to these substances of persons engaged in PVC film meat wrapping operations. The research project included five types of films, only one of which. Type RMF-61HY, is used for meat-wrapping operations. This discussion is limited to industrial hygiene aspects of the experimental results utilizing Type RMF61HY film, since the other four types included in the research project are used for such other purposes as produce wrapping and carcass wrapping, operations not under consideration here. Furthermore, data are included only on Batch No. 1588 of this type film, since only this batch of RMF-61HY film, as discussed in the research paper, was of sufficiently recent origin to be handled in a representative manner and consequently to produce representative results. The plasticizer used in this film is di-(2-ethylhexyl) adipate, commonly called dioctyladipate (DOA). The experimental data in the following discussion are a|4 from the cited research project, except where specifically noted. Copyrgnt 1900, Amancin Industrial Hyg*na Association 50S Am. Ind. Hyg. Assoc. J. (41) July. 1980 breathing zone air samples hydrogen chloride I hrcc air samples were collected during hot-wire cutting of I'YC film RMF-61HY inaclosedroom42.3tn3( 1500ft.3)in . nlume with dimensions as given in the research paper that also notes the sampling point at the breathing zone of the operator. Even though an extremely sensitive analytical method was used, the amount of HC1 in the air was not efficient to permit a quantitative result. The largest sample collected. 75 liters, established that an average of less than 0.1 part per million (ppm) of HC1 was present over the 75minute sampling time. With 240 cuts of the PVC film being made during this period, the HC1 concentration would have increased from zero at the start to something less than 0.2 ppm at the termination of the sampling period for the average to have been less than 0.1 ppm. Actually, the increase in the concentration time would not be a straight line but would be a hyperbolic curve asymptotic to a maximum at equilibrium between introduction of HC1 into the air and the several factors causing its removal from the air. These factors include solubility of the HC1 in moisture (a greater factor in meat-wrapping rooms than in the test room), adsorption on and reaction with the surfaces contacted, and a small but definite amount of dilution from convection currents through loosely fitting doors and intermittent opening of doors. The investigators note that the value of less than 0.1 ppm is less than l /50 of the threshold limit value (TLV) for HCl; |but conservatively, recognizing a build-up with passage of Rime, suggest that the continuing exposure might be on the order of less than !, 10 of the TLV, A series of laboratory tests conducted by other investigators''" using artificially severe operating conditions causing excessively smoky cuts gave results of 1.9 ppm HCl at a sampling location 7 in. above the hot wire and 0.2 ppm HCl at breathing level 17-18 in. above the sealing pad. A calculation is of interest of the amount of diluting air that would be required to keep the concentration of HCl below 1/10 of its TLV using the formula in the Industrial Ventilation Manual of the American Conference of Governmental Industrial Hygienists (ACGIH).*7' The amount of HCl released into the air per minute was calculated from the amount per cut (4 micrograms -- the average of six cuts with Batch 1588 of film RMF-61HY) times the operating rate of 192 cuts per hour (240 actual cuts over a 75-minute period). A K. value is incorporated in the formula toserveasa multi-purpose safetyfactor to maintain air concentrations well below the TLV. The K value may vary from 3 to 10 with the latter resulting in the highest amount of dilution air required. Using this maximum K value of 10, the amount of dilution air required for each hot wire cutting unit would be only 0.17 m3 (6 ft.3) per hour. More than this amount of air change occurs normally even without benefit of mechanical ventilation. For comparisons of the findings under these test conditions with results of air analyses taken at the breathing zone of the operator during hot-wire cutting of PVC film in four different stores under normal operating conditions. American Industrial Hygiene Association JOURNAL (tl) 7/80 James*1' reports that the average of eight determinations was 0.57 ppm HCl, close to I /10 of the TLV, with a maximum of 1.49 ppm HCl. benzene Following the 240 hot-wire cuts in the test room prior to ventilating the room, an air sample was collected for 20 minutes for determination of low-boiling hydrocarbons such as benzene and 2-ethyl-1-hexene. No low-boiling hydrocarbons were found, using the GC/ MS unit capable of detecting benzene in the order of 3 micrograms. With the 20liter air sample, as little as 0.05 ppm would have been detected. Accordingly, the accumulated concentration of benzene produced was necessarily Jess than 1/20 of the proposed OSH A TLV limit of 1 ppm and less than 1 /200 of the existing OSHA TLV of 10 ppm. estimates of room-air concentrations of degradation products from PVC film type RMF-61-HY (batch 1588) data used in estimates In calculating the estimates of room-air concentrations o; degradation products, the average amount from 250 cuts, essentially the same as the maximum number of cuts used in the breathing zone samples, was related to a room of 42.3 m3 (1500 ft.3), the volume of the test room. With this number of cuts, it was considered that equilibrium conditions would be reached. For the degradation products, HCl, plasticizer (DOA), benzene, toluene, carbon monoxide, the average of all test runs on Batch 1588 as reported in the research paper15' are used in the calculations. Since only Batch 1959 was used for the acrolein tests, these results were used. For benzyl chloride, negative results from 15 cuts indicated less than 1 /ig, the mass spectrometer detection limit. For the remainder of the degradation products as listed in Table I, determinations were conducted by gas chromato graph/mass spectrometer. As discussed in the research paper,*5' smoky cuts were required to produce enough degradation product for quantitative results with this latter group of degradation products. As benzene amounts could be determined from normal cuts as well as from smoky cuts, the ratio of these values for benzene was applied to the smoky cut results of these other products to obtain a value for normal cuts. The average values for these additional degradation products have been taken as 9/10 of those listed from Batch 1588 in Table VII of the research paper*5' for clean cuts and 1/10 of those listed for smoky cuts since, according to the investigators, approximately one of ten cuts tended to be smoky. threshold limit values Threshold limit values are listed in Table I for each of the substances for which these have been established by ACGIH or OSHA except that for benzene for which the value currently proposed by OSHA is listed. No threshold limit value has been suggested by these 509 u- TABLE I Estimation of Average Room-Air Concentrations of Degradation Products Resulting from Hot-Wire Cutting of PVC Film Type RMF-61HY (Batch 1588) Degradation Product Average Amount Average Concentration in Percent TLV (ppm) Produced per Cut 1500 ft.1 Room from 250 Cuts of TLV Hydrogen chloride 5 4 P9 0.016 ppm 0.3 Plasticizer (DOA) A 36 P9 0.014 ppm A Benzene 1" 92 ng 0.0002 ppm 0.02 30 Toluene 100 53 ng 0.00008 ppm 0.00008 fi (/) Acrolein 0.1 120 ng 0.0003 ppm 0.3 -A Carbon monoxide 50 1.75 pg 0.01 ppm 0.02 w Benzyl chloride . 1 0.07 pg 0.0002 ppm 0.02 0 -4 2-Ethyl-1 -hexene A 210 ng 0.0003 ppm A 4* Ethyl benzene 100 21 ng 0.00003 ppm 0.00003 Styrene' 100 37 ng 0.00005 ppm 0.00005 n-Propylbenzene 100' 37 ng 0.00005 ppm 0.00005 Propenylbenzenec 100A 13 ng 0.00002 ppm 0.00002 Indene1 10 13 ng 0.00002 ppm 0.0002 Naphthalene' Unidentified 10 6 ng A 52 ng 0.00001 ppm 0.0003 m/m' 0.0001 A Unidentified A 6 ng 0.00004 m/m3 A 'Refer to text "Proposed OSHA value 'Unconfirmed identification agencies for DOA. An experiment of an 8-hour exposure of rats to saturated vapor resulted in no deaths.191 NIOSH12' cites a Monsanto Company report that "10 rats were exposedfor 4 hours to 900 mg/m1 (59 ppm) generated at 89 C and observedfor 14 days. None of the rats died and no untoward behavioral reactions were observed." Later experiments1101 with 6-hour exposure to 200 mg/m5 gave similar results. Slight ^irritation occurred from 24-hour contact of rabbit skin (1.9/8.0) and from liquid DOA in the eye (1.4/110.0) with normal appearance 48 hours later. The LD>o on intravenous injection of the rat has been reported111' as 900 mg/kg and of the rabbit as 540 mg/kg, indicating DOA as "slightly /ox/c."112'11' These inhalation studies included only survival or death on acute exposure and observation over 14 days. Toxicological data on substances of similar constitution are sometimes helpful in suggesting a probable TLV but we know of no substances similar to DOA with such information. Although neither ACGIH nor OSHA have TLV's for npropylbenzene or propenylbenzene, the close structural analogy of the former substance with ethylbenzene and of the latter substance with styrene indicates a TLV of 100 ppm as applicable to each of these substances. No TLV has been published for 2-ethyl-1-hexene; but from analogy with similar unsaturated hydrocarbons,114' its principal action may be expected to be asphyxiant and anesthetic. Suggestions for threshold limit values for the substances that caused film RMF-61HY to produce the two unidentified peaks noted in the research paper and included in Table I present a problem. An approach to whether t is a reasonable probability that concentrations of t unidentified substances as low as 0.0003 mg/m3 or 0.00004 mg/m3 could cause a physiological effect such as airway hyperreactivity may best be through a comparison with concentrations of known sensitizers at their threshold limit values. Of nearly 600 chemical substances for which TLV's have been published by ACGIH,1,31 the substances that must be kept at the lowest concentrations to avoid causation of airway hyperreactivity are the isocyanates, of which toluene diisocyanate (TDI) has been most extensively studied. A recent criteria document published by the National Institute for Occupational Safety and Health1'6' stipulates a limiting concentration of 0.005 ppm for diisocyanates. For TDI, this value is equivalent to 0.035 mg/m3. This standard is "designed to protect the health and providefor the safety of employees for up to a 10-hour workshift, 40-hour workweek, over a working lifetime." The concentrations of 0.0003 mg/m5 and 0.00004 mg/ m3 are thus 0.9% and 0.11%, respectively, of what is considered an acceptable concentration for the most severe sensitizer on which quantitative exposure/response data are available. Comparison values for these unidentified substances must be in terms of milligrams per cubic meter as lack of knowledge of their molecular weights prevents calculation of the corresponding parts per million values. The TLV of HC1 is well established at 5 ppm, but particulate DOA is present as an aerosol on which som^m the HC1 may become attached, the question arises as to 510 Am. Im). Hyg, Assoc. J. (41) July. 1980 xhether concentrations of somewhat less than 5 ppm may, through this mechanism, reach the lower respiratory areas nd cause irritation in these areas. Such gas/particle interaction has been discussed in relation to fire -uuations,"7'"" but in theexperiment with HCl/sootaerosol reactions,'17' the concentrations of HC1 were over 100 ppm, and in that with HCl/water aerosol reactions,"*' concentrations of 60, 600, and 6000 ppm gas-phase HC1 '.vere used. All of these concentrations are far beyond the range of HC1 produced in hot-wire cutting of PVC film and so not applicable to the operations under consideration. The most extensive researches on potentiation of the effect of an irritating gas by aerosols are those conducted over more than a decade by an investigator using sulfur dioxide as the irritating gas. In one of these research projects where the irritant gas was inhaled with each of a variety of aerosols,'1,1 it is stated that "It is plain from the data presented in this paper that allaerosols do not potentiate the response to sulfur dioxide." and in a subsequent paper,'20' that "neither iron oxide nor open hearthfurnace dust affect the response to sulfur dioxide." On the basis of these results, it cannot be assumed that any given aerosol will potentiate the action of an irritant gas without demonstration through specific research. Such research has not been conducted concerning the potentiation of sub-TLV levels of HC1 by DOA aerosol. All of the substances listed in Table I are readily volatile liquids or gases with the exception of DOA and naphthalene. It was found by the research investigators that most of the DOA volatilized by the hot wire condensed on the surrounding hood surfaces, the portion remaining as a vapor to be collected by an impinger being too small for quantitative measurement in an initial experiment. It is believed that, in use of hot-wire film cutters in meat wrapping operations, a portion of the DOA will condense onto adjoining surfaces but that some portion of the amount volatilized will reach the breathing zone of the operator. As no publications of results of air analyses for DOA at the operator's breathing zone under normal operating conditions are available, just what this portion or the total amount volatilized will be remains conjectural. From the calculation of the average amount recovered from washings of the hood surfaces on making cuts of film Batch 1588, this concentration would be some value less than 0.014 ppm. As listed in the final column of Table I, the concentrations of the degradation products for which TLV values are assigned on hot-wire cutting of RMF-6IHY film. Batch 1588, on 250 cuts in a 1500 cubic foot room are no greater than 0.3% of their respective TLV's. cool rod PVC film cutting On finding no HC1 evolved when the so-called cool rod cutting device was used or in the air flushed from the top of a flask in which a sample of film Batch 1588 was maintained at the cool rod temperature of 135 C (275 F), it appears probable that PVC does not degrade at the cool rod temperature. The finding of a total of 6.3 micrograms of HC1 in rinses of surfaces of the flask and tubing leading to Amencen Industrul Hygiene Association JOURNAL (41) 7/80 the sampling bubbler indicates cither that the amount of HC1 that may have been produced by degradation was a thousandth or less of that produced by hot-wire cutting or that this minute amount may represent contamination. Negative results for benzene and toluene also indicated that PVC does not thermally degrade at the cool rod temperature. The amount of DOA volatilized by the cool rod device within the hood was in the same range as when using the hot wire, this result being ascribed to the fact that the rod was not being turned off during sampling. Keeping the cool rod turned on during sampling would increase the temperature within the hood, thus causing more of the plasticizer to remain volatile. conclusion An analysis of the results of the research'5' on thermal degradation products of PVC film using the hot-wire cutting device in meat-wrapping operations showed that the average concentration of hydrogen chloride as produced in a closed room by hot-wire film cutting was less than 2 percent of the OSHA TLV and that of benzene less than 5 percent of the proposed OSHA TLV and less than 0.5 percent of the current OSHA TLV. Just how much less these values actually were is indicated by the results of the experimental gas chromatograph/mass spectrograph results as presented in Table I. These GC/ MS results indicated that the concentration of degradation products for which TLV's are assigned would be no greater than 0.3% of acceptable limits and in most instances much lower. Thus it would appear that any workroom exposures to such products would be insignificant from an industrial hygiene standpoint. For the DOA, the concentration is less than 0.014 ppm; how much less is not determinable due to the presence of the close surrounding hood structure under experimental conditions, a factor that is not existent under actual operating conditions. Information presently available does not indicate that exposure to DOA causes airway hyperreactivity. Investigation of the cool rod PVC film cutting device indicated that PVC does not degrade at the temperature of the cool rod but that the amount of DOA volatilized within the hood was comparable to that using the hot-wire device. The continued elevated temperature within the closed hood would not be a factor in the actual meat-wrapping operation and lesser volatilization of the DOA would accordingly be expected even though in meat wrapping the cool rod is kept on. In accordance with the industrial hygiene viewpoint that all exposures should be kept as low as is practicably feast' ' the cool rod device is to be recommended. references 1. Vandervort, R.: Polyvinyl Chloride Meat Wrapping Study. Bureau of Occupational Safety and Health, Cincin OH (1971). 2. Vandervort, R. and S.M. Brooks: Health Hazardivalus R&S 131075 Determination. Report No. 74-24, 92, 95-246, National Institute (or Occupational Safety and Health, Cincinnati, OH (1975). 3. Vandervort, R. and S.M, Brooks: Polyvinyl Chloride Film Thermal Decomposition Products as an Occupational Illness. 1. Environmental Exposures and Toxicology. J. Occup. Med. 79188-191 (1977). 4. Brooks. S.M. and R. Vandervort: Polyvinyl Chloride Film Thermal Decomposition Products as an Occupational Illness. 2. Clinical Studies. J. Occup. Med. 79:192-196 (1977). 5. Boettner, E.A. and G. Ball: Thermal Degradation Products from PVC Film in Food-wrapping Operations. Am. ind. Hyg. Assoc. J. 47:513-522 (1980). 6. Van Houten, R.W., A.L. Cudworth and C.H. Irvine: Evaluation and Reduction of Air Contaminants Produced by Thermal Cutting and Sealing of PVC Packaging Film. Am. Ind. Hyg. Assoc. J. 35.218-222 (1974). 7. ACGIH: Industrial Ventilation -- A ManualofRecommended Practices. 15th Ed. pp. 2-1, 2. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1978). 8. James. D.G.: Cool Rod Film Cutting Device Ends Packaging Room Fumes. Package Eng. (March, 1975). 9. Smyth, H.F., Jr.. C.P. Carpenter and C.S. Weil: Range Finding Toxicity Data: List IV. A.M.A. Arch. Ind. Hyg. and Occup. Med. 4:119-122 (1951). 10. Monsanto Company: Toxicity Information. St. Louis, MO (1976). 11. Edgewood Arsenal: Medical Research Laboratory Reports. MD. No. 256 (1954), 12. NIO S H: Limiting Doses According to Route ofAdministration to Experimental Animals Causing Death. Registry of Toxic Effects of Chemical Substances. Vol. 1, 1977 Ed., p. xxvi. National Institute for Occupational Safety and Health, Rockville. MD (1977). 13. Spector, W.S., Ed.: Handbook of Toxicology, Vol. 7, Acute Toxicides, p. 4. W.B. Saunders, Philadelphia (1956). 14. Gerarde, H.W.: The Aliphatic (Open Chain, Acycli Hydrocarbons, Chapter XXVIII in Industrial Hygiene a<W0 Toxicology, 2nd Ed., Vol. II, F.A. Patty, Ed., p. 1204. Interscience Publishers, New York (1962). 15. ACGIH: TLVs Threshold Limit Values for Chemical Substances in Workroom Air Adopted by ACGIH for 1979. American Conference of Governmental Industrial Hygienists, Cincinnati, OH (1979). 16. NIOSH: Criteria for a Recommended Standard . . . Occupational Exposure to Diisocyanates. National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication 78-215 (Sept., 1978). 17. Stone, J.P. and R.N. Hazlett: The Transport of Hydrogen Chloride by Soot from Burning Polyvinyl Chloride. J. Eire Flammability 4:42-51 (1973). 18. Stone. J.P.: Transport of Hydrogen Chloride by Water Aerosol in Simulated Fires. J. Fire Flammability/Combust. Toxicol. 2:127-138 (1975). 19. Amdur. M.O. and O. Underhill: The Effect of Various Aerosols on the Response of Guinea Pigs to Sulfur Dioxide. Arch. Environ. Health 76:460-468 (1968). 20. Amdur, M.O. and D.W. Underhill: Response of Guinea Pigs to a Combination of Sulfur Dioxide and Open Hearth Dust. J. Air Poll. Control Assoc. 20:31-34 (1970). CALL FOR PAPERS The 21st annual American Industrial Hygiene Conference for the 1981 will be held at the Memorial Coliseum, Portland, OR, May 24-29, 1981. American Forms for submission of titles and abstracts for papers may be Industrial obtained from the Managing Director's office, American Indus Hygiene trial Hygiene Association, 475 Wolf Ledges Parkway, Akron, OH Conference 44311 (216) 762-7294. All abstracts must be submitted n than October 31, 1980. lat r Papers will be presented from the platform or in poster sessions. If the author prefers a poster session, this should be indicated on the form provided. Depending on circumstances, it may be necessary to assign additional papers to the poster sessions, even though the author has indicated a preference for platform presentation. R&S 131076 512 Am. lad. Hyt Assoc. J. (41) July, 1980