Document QjGkmGDbDgqERk84yzJnGavE

'* V ; A|>R[L, 1969 ( CHEMICALS 283 000 i 'i imj ! *<y. ; I w.lt nt4 I* ibf oti Ii of rxw tn4 4erv Mex >fid J76) i jt i * j y ifi \ CCtt to ind of j? as%>. ; > <* ilieWo*. a, f. tr uiJ Tickinl ihlorid- jm) %n< (UK). ithyl*** } x> \T> f i%cn j Oi \U ! PQ xdrvJ * > f TOXSC GASES FROM PVC BN HOUSEHOLD FERES By G. W. V. STARK, Ministry of Technology and Fire Offices' Committee Joint Fire Research Organization rCTHfl smoke and toxic gases produced from combustible I materials in a building on fire can reduce the chances of escape of the occupants and put their lives in jeopardy. Records show that roughly half the deaths in fires in the United Kingdom arc attributable to smoke and gases. The principal toxic gas from burning traditional building materials, such as wood, is carbon monoxide, but newer combustible building materials, such as plastics, may evolve additional toxic gases. The hazards due to ccllulosic and other combustible building materials are being examined, with the aim of quantifying the toxic gas and smoke hazards. Some results obtained on the effect of the addition of PVC to ccllulosic fire loads on the toxic gases produced in small scale laboratory fires are presented here. Fig. I. Model coripartment showing wall linings and ccllulosic crib v /] : ;!M \; Tests and Results The tests were made in a 0.9 m cubical compartment lined with asbestos, the front of which could be opened for loading the chamber with combustibles, and fitted at the top with a vent of the full width of the compartment and of adjustable depth. Fig. 1 shows the compartment with the front open containing the ccllulosic fire (a crib of wood fibre insulating board) and wall linings of rigid PVC. The ccllulosic crib was ignited electrically, and samples of gas were withdrawn from time to time during the test for analysis of permanent gases and hydrogen chloride. The temperature of the issuing combustion gases was measured during a test, their total rate of evolution was calculated using the flow equation of Kawagoe (the ventilating condition in these tests required the discharge coefficient to be altered to 0.9) and the rate of evolution of the toxic gases was then obtained from the composition of the combustion gas.O> Tests were made with ccllulosic fire loads of 6.4 and 12.8 kg in the crib and with vents of 5 cm (equivalent in an average room to an open fan-light) and 10 and 15 cm (equivalent in an average room to an open door). In most tests the three fixed walls of the compartment were lined with 1.5, 3 or 6 nim thick sheets of rigid PVC. A few lests were made with a board consisting of 0.5 mm rigid PVC sheet laminated on to 4.5 mm hardboard. The effect of a different arrangement of the plastic in relation to the fire, as. for example, in furniture incorporating plastics was examined by further tests in which sticks of rigid PVC were incorporated in the ccllulosic crib; the weights of plastic u'cd were 2.8 and 5.6 kg, the latter being the weight of the 1-5 mm wall lining. Temperature records were made for the gases emerging `rm the vent. In all tests burning started with the crib 'mouldering and producing dense white smoke for a few minutes, which was followed by a Hash ignition of the smoke lr-d a resulting sharp rise in temperature, up to about 700"C. la tests with the 5 cm vent, this was followed by smouldering cmbustion, the temperature of the emergent gases remainmg at a steady low value of about 230'C. With the 10 cm Vctit, smouldering alternated with llash ignition in most tests, 'hilc at the largest vent size the flash ignition after initial miouldering was generally followed by continuous flaming '"minis!ion. Combustion usually proceeded to completion in ''Ms at the two larger vent sizes, hut in many tests at `the 'Tallest vent size the fire went out before combustion was lm [dele. The patterns of cvolulion of hydrogen chloride ami carbon a?: -O. JJ evolved later than carbon monoxide, the delay increasing with decreasing vent size. In tests with the 5 cm vent, the delay was a minimum of 30 minutes, but usually much longer, for tests with the PVC present as wall linings. Shorter delays occurred when the PVC was incorporated in the crib, but the rates of evolution were lower than when the plastic was present as a wall lining. (Fig. 2). In all tests carbon monoxide was evolved a few minutes after ignition. The rale of evolution was little affected bv wall linings of PVC but was reduced in the test in which the larger weight of plastic was incorporated in the crib. (Fig. 3). Discussion The results obtained in these tests may be used to assess the elfcet of PVC in burning compartments on the toxic gases escaping into the remainder of a building, for the_worst condition in which no gases escape outside the building. The risk will then vary with the mode of burniniy4.nd the time from ignition during which occupants arc e.xpoifcwto the gases. The growth of a flaming tire is rapid and Cfl'P0 or rescue must take place promptly to avoid ex[AA>rc u' excessive heat or toxic gases. However, gas cvolutwj could occur more slowly, and without excessive neat pWductU'n for longer limes if the (ire started by smoulddtWg and continued with restricted ventilation before discoyffy; 'or this report exposure times of up to one flour bcfoj^cscapc or rescue have been assumed. The assessment of the effect of hydrogen .chloride fin escape is not straightforward. Atmospheres contajping 100 parts pel million or more of hydrogen chloride "re intolerable to breathe.'-) while about l.?0<) parts per million could prose lethal for exposures of half an hour.'TI The lower concen tration could augment the effects of smoke and other gases in impeding escape, but on the other hand the irritancv ol hydrogen chloride could gixe early xxariiing to tile occupant- CHEMl^AVIi i4 \ TOXIC GAS1 % utOM PYC IN HOUSEHOLD FIRES (COIlCltuh`l,t!."! ASj) RUBBER AND PLASTICS AGF. since other workers have shown that for a wide range of remote from iliU compartment on fire. Thus the presence of conditions the chlorine content of burning PVC is refenwJ hydrogen chloride could not be relied upon to ensure escape. The above value, for hazardous levels of hydrogen chloride - air can bo compared with the value of 3.(XX) parts per illion of c>ti|ni(l monoxide which could prove lethal in halt ..n hour; cat bon monoxide is odourless and therefore may provide no w lunuig of its presencc.DJ The results indicate that when the ventilation is small (5 cm deep vent, equivalent to an open fan-light) hydrogen quantitatively as hydrogen chloride^- <*> the maximum level of risk due to hydrogen chloride in this case can be calculate,! It can thus be shown that the hydrogen chloride from coating (usually less than 0.1 mm) of the plastic on wallpaper in a room does not add much to the risk presented by the normal content of ccllulosic matter. For greater loads >: fiVC full account must be taken of the actual rate ,'t evolution of hydrogen chloride, which has been shown to van chloride from pvc; would make little or no contribution to the hazard idicndy presented by carbon monoxide from witAh tifmulele. r account of the programme of tests on the traditional cctlnlnsic combustibles. Assuming that the rate combustion of cellulose and PVC. including the series of burning is controlled solely by ventilation, it can be full scale experiments will be published later. calculated fi.m, ,nir results that about 30m3 of carbon monoxide would be generated in the first hour from a room Acknowledgement 4 m x 4 nt x t.n, high ventilated through an opening 1 m x 0.5 m at the lop of the room. This quantity of carbon monoxide could contaminate 10.000 m3 to a level hazardous to life: as ibis volume is many times the volume of the The paper is Crown copyright, reproduced by perniiv-i.'; of the Controller HM Stationery Office, ft is conlril'nd-- bv permission of the Director of the Fire Research of the Ministry of Technology and Fire Offices' Committer average dwelling space, the hazard is a real one. The above assessments are made on the assumption that the size of tin- burning compartment has no effect on the rate of combustion ,,f t|,e plastic. Some large scale tests arc in progress in a compartment, measuring 4mx8mx3m high, using similai pl.i-.tics mllltailtte.!riIa*UlsJ txov e--x*a...m.....i.ne the clfcct of scale. Conditions would, however, be d*if'f*e*-r-e--n*t if the ventilattiioonn were substantially higher than that of an open fan-light. 1, Kaw;.-..f, K., Fire behavioRuErFinERroEoNmC.E,.S M: inbtry of Convlrucl.o" r -'* in'* Research Institute Report No, 27, Ttikio. 2. Patty, I*. A., Imltulrtul hygiene and lo.vtcofoay, iVew York, HWeilnedjre.rson, Y,, and Hazard, H. W., Noxious **jse< and the p**.*r. of respiration io/lncncinu their action. New York. W4J <2d KKaesinhhiPoihti,t lP).ub1li,,shainndg SCtoarrpk.. G. W. V'., The Generation of carh*w ,( by iirrr in compartoicnU. Joint Fire Research On:ani/>tM* * ** Provided enough pvc were present in a room on fire, the hydrogen cldoudc formed from its combustion would add to the risk pi.-,ruled by carbon monoxide from traditional ccllulosic mill,K. which need not difier much from that SKhfscccnaarnrl,i NI)ti.l.c TNhoe. rm61a4l/19tlc6u6,r.idatian of polymers nv<r the rf (J', 6iH):*C. Royal Aircraft tvialli>Ument Technical Note Cbcn. * 'lJa'vrunclhioiyrao.oiYih,,, 1a9n5d6. Sutiti. K. Thermal decomposition prorfoc** *' ^, given above m |( naming lire developed quickly a substantial vinyl chloride. J. Ajpl. Chem.. 1967, /7 Ui). 364*6. ppaanrt. oS'lf the priho,-i,iiu,,;; wwoouuliud buet; b...u...r..n...t....i.n......t.h.e- first hour. _T__h_e__r_e_fore. _ ________________________ _ porn- THE ECONOMICS AMO PERFORMANCE OF LEAD STABILISERS {a>ticlmU;l i.... I 2S5) the volume i, -., ,iivity of the PVC compound containing lis sbibiUw-i i-j i-^trerttely high. In certain ..mi, |s sucj, as the production of rigid pipe, profiles, si.. . t , -ill usion, and rigid injection mouldings, which fi.-ivt _n,uv become major growth areas in the con sumption .'I I v< tiibasic lead sulphate is often used as the sole stabile., . b. . ausc of the higher processing temperatures involved \ -I-1,1,,,na) protection against ultra-violet light may he obiai.., ,| |,y replacing part or all of Ibis stabiliser bv dibasic I. ..v- 'll"- ........ 11' ...... ...... acting u^"nngid HVC can prolong the Hf<- ,'1 pigments -----fabSruicmatmedariasrintigclei.t can be said th_ at t__he s,,ta,,Kb;il!iks,err 0'h'<.---- confe-r on the plastic the necessary properties f#r *' ` use. Where non-toxic properties and transpafvKS ' required the- use of lead stabilisers should no! he ssiclercd. However, if heal stability, resistance to d-. lion by ultra-violet light or good electrical propc.m'^ required lead stabilisers should he used as tfies >' these properties at the lowest cost to the co.'!,l'',u' ' This is particularly so when high temperature pro,-' oo - .J/V-/<?,' /377_. ^ GASES FROM BURNING PVC C. A. Clark B. F. Goodrich Chemical Company Development Center, Avon Lake, Ohio a--------a eju_c T<dJ} IhT&QQUCTlOM From che smell beginnings about thirty five years ego -and particularly since the end of Vorld War 11 -- the plastics Industry has become a major visible contributor to our life style. This is quite evident In the improvement In quality and availability of those utilitarian and aesthetic things ve consider necessary for living today. Those of os who have played che part of contributor to this growing use of plastics in today's society are veil acquainted with the excitement of these resin, processing and product developments. Our greatest goal has been, and is, to bring to the area of product development the best combination of those attributes chat will serve the product's needs. These can be Itemized In many ways but it will suffice co say that we seek Co optimise desirable physical strength; chemical, flame and electrical resistance; total economics of materials and processing; as well as the aesthetic properties of color and transparency. Safety for processors and consumers has been "part and parcel" of these produce developments and the many acceptances in the market place are tribute to the success of these endeavors, particularly in the vinyl plastle Industry. We see tough transparent containers that serve in an outstanding way the package requirements for content security and safety, that provide content visibility and that resist breakage which can result In injury and economic loss to the consumer. In like manner, ve may also mention the flame resistance and toughness of such products as wire and cable insulation and sheathing, phonograph records, flooring, pipe and building products. From this background on the detailed attention paid by you to plastic product development. It may seem strange that the whole industry, and vinyl plastics In particular, has been targeted, mostly in the lay press, ss a serious threat to environmental quality. Please note Figure l. When you dig Into the background of these expressed con cerns you find that most of thee have to do with the nature of gases evolved when Polyvinyl Chloride Is forced to burn. This may be either the accidental burning of che PVC content of a building along with the more easily combustible ocher materials of construction or the burning of PVC along with ocher waste products In an incinerator. Some of the questions raised are shown in Figure 2. It is our Intent here to take a look at the results reported by scientists frdn different areas of the world so that we all may have a better understanding of Just what does happen when PVC burns. That PVC is difficult co ignite is a veil recognized fact and HLlado^ reports the flash-Ignitton temperature of 39lC (735F) and self-Ignition temperature of 4WC (8 50F) Ve would consider the burning of PVC in line with thecandle-type mechanism described by Fenlmore^,and others^. In this way we can model che burning by considering Ch.it exterior beat initiates ehern3l degradation or pyrolysis of the polymer In the condensed or solid phase to produce fuel ?o cocdjustlon In che gas phase. Pyrolysis of the material in the absence of oxygen, then, provides us with a means to determine the fuel components that would oxidize In the presence of PYROLYSIS The decomposition of PVC resin will produce a thermogravlmetrle plot such as that In Figure 3. This is' a graphical picture of PVC weight loss when heated In an Inert atr.osphere. Here,we can see that a large weight loss (approximately 58 per cent) occurs around 300C (572F) followed by a slower loss of volatiles (approximately 38 per cent) out to 60QC (1112F) and leaving a snail amount (approximately 4 per cent) of ash. Ve are, of course, curious about the chemical nature of these pyrolysis products. Before ve look into the reported analyses of pyrolysis and combustion products of PVC, I believe it is necessary chat w* look at these results with che knowledge that each investigator developed apechod of thermal treatment and product analysis os dictated by bis own approach and instrumentation available. I suppose I am really saying chat each study is somewhat indivi dual but that all represent the results of planned scientific experiments. Some of the major variables In these studies are the method and rate of application of che heat flux, static or dynamic gas flow, and the methods and techniques of the gas analyses. Since space does not allow che full incorporation of these analytical methods, the reader is directed co che full reports as indicated in the references. In 1959, Strottfeerg^ reported on thermal degradation of PVC in a vacuum by first stripping the resin of HC1 at tenperacures up to 350C (662F) for 30 minutes. The resulting residue was then heated in a furnace at 400C (752?) for 30 minutes end the volatile products from this second heating were identified by mass spectrometry. Stromberg identified approximately 25 hydrocarbon product* vfeb ethylene and benzene predominant. Earlier work by Bradt and fohler7 showed chac KCl is the pri mary decomposition produce from 127C to 300C (251? to 572F) along with some benzene; and, above 300C (572F). a great variety of hydrocarbons evolve. Ko chlorine nor chlorinated hydrocarbons were reported in che gases. At a later time, Ohtaml and Ishikawa pyroiyted ?VC in a nitrogen atmojphere and analyzed che degradation products by infrared and ultraviolet speceroscopy. They found chac: (1) the pyrolysis products, other than KCl, consisted of arociatic and aliphatic hydrocarbons, and (2) the types of pyrolysis products were influenced by the stereoregularity (tacticity) In che original polymer. Additional qualitative or quantitative measurements were not made. Hoffz and associates? used a high frequency pyrolyser Co degrade PVC as well as a number of other polymers. They >> separated che products from PVC by gas chromatography and i J* reported that che hydrocarbon degradation produces consisted \J\ only of aromatic compounds. Neither aliphatic hydrocarbon nor^ chlorine was Identified In the volatiles. <r. In a more recent study O'Hara^ degraded PVC and PVC oplastlaols with a radiant type furnace at 600C (lll2f) In a helium gas stream and analyzed the products by a combination pof gas chroaatograohlc and mass spyccro?x?tric technique, 600' fcsoa* chosen co provide pyrolysis products In a scanner similar to those existing under fire conditions. It is aiso^oced chat this temperature is above che self-Ignltion ce-aperacure (850F) mentioned previously for FVC^. 623 BFGS^ 58 0*htir reports no degradation products resulting from plasticizer Interaction In the pUsclsols. He also reports that a stoichiometric amount f HCl Is released (53.3 per cent) froo PVC based on the chlorine In the polymer. The remaining products were hydrocarbon* (~38 per cent) and a chlorine-free carbonaceous *h o( ) to 4 per cent of the original polymer*. Combining these background studies wc can now put label* on the thermogravImetric plot we saw In Figure 3. Please note Figure 6. Here we see chat unburnable HCl Is the primary product up to 300C <5?2F). Above 300C we see the production of burn able volatile hydrocarbons and ash. In the O'Hara* study the hydrocarbon fraction was' further analysed in a gas-chromatograph to provide a qualitative and quantitative analysis. In Table 1 we see the results of three runs chat demonstrate the reproducibility of this technique. Here we see chat the pyrolysis of PVC at 600C (1112F) produces a series of aliphatic and aromatic hydrocarbons. The chromatograph areas shown closely reflect the mole per cent conteor. The amount of aromatic products is greater than that of aliphatic*, and benzene Is the major organic component of the more chan 25 identified. Only one chlorinated product, chlorobenzene, was found in minor amounts. Ho chlorine was found. In another recent study, O'Hara*'** described a highly reproducible method for HCl analysis from pyrolyzed PVC. He also showed chat the outflow of HCl in Che pyrolysis gas could be reduced by compounding with basic fillers such as calcium carbonate, potassium carbonate and magnesium oxide, among other*. Under his conditions of short time flane exposure, the combustion of a number of pyrolysis residues In air revealed that the amount of HCl absorbed by the basic filler vas retained in the non-carbonaceous ash. C0M3L:STI0* Now that we have considered the nature of Che gaseous products supplied by pyrolyzlng PVC in the absence of oxygen, let'* cake a look at reports of scientific investigations of the, perhaps, more practical exposure, combustion. Host of the combustion studies of PVC prior to 1959 analyzed the gases by colorimetric and gravimetric methods. An extensive review of chose original scientific investigations w,v published in 1963 by Lndervriters' Laboratories** *nd Include* Information on the combustion and pyrolysis of other polymers and natural building materials. It Is consistently reported that combustion of PVC produces large amounts of hydrogen chloride, carbon dioxide and carbon monoxide and minor amounts of hydrocarbon*. This vas accompanied by severe oxygen depletion and, very occasionally, traces of phosgene and vinyl chloride. Recent studies of che old coloriaeerlc and gravimetric method*^,14 have shown chat the presence of large amounts of hydrogen chloride can Interfere and cause erroneous reporting of the presence of phosgene# In 1967, Tsuchiya and Sual^ decomposed PVC *C 350, 600 *nd BC0C (662, 1112 and 1672F) in a ceramic boat inserted In a furnace through which they passed helium gas for pyrolysis, or air in excess for complete combustion. When products of d-compo*icion were analyzed, primarily by gas chromatography, they found chat the main decomposition product in both cases w.v* hydrogen chloride. The amount of hydrogan chloride produced in an inert atmosphere approached the theoretical value expected tor PVC. Inasmuch as these Investigators measured only gaseous hydrogen chloride, the amount determined In an oxidizing atmosphere vas slightly tower because water vapor produced in an atmosphere of air absorbed some of rhe hydrogen chloride. L'nJcr combustion conditions, the main change froa pyroly sis fcjs effluent was the presence of large amounts of carbon dioxide nml monoxide with a corresponding reduction in hydro carbon content. Other oxidation products such ai acid, i 1 'i.'JiyiJt:s, nlcohols and ketones were not found. Neither chlorine nor phosgene was detected chough sensitive detection methods vere used. In * more recent report, Boettner and associates*^ reported combustion pas analyses on three PVC polymers, one copolymer with vinyl acetate and three related compounds. They *n*lytcd the collected gases from combustion -- Initially by (nfrered spectroscopy' ...d, In detail, by a combination of gas chromatography and a mass spectrometer. The combustion for quantitative gas analyses was done in furnace by heating, after *n initial heating at room temperature from 200C Co * 600C (392 to UUF) at a rate of 3C per minute. Air vas supplied to the sample ac a rate which, when integrated over Che.entire cun, would result in about twice the amount of oxygen necessary to convert all carbon to carbon dioxide and ac higher and lover levels as well. Under these conditions, the resin saroplea completely disappeared with no measurable residue and the compounds left a residue related to the presence of inorganic matter In the recipe. Boettner reported that combust ion gases from PVC resin contained approximately 50 different chemical compound* and quantitatively analyzed more than 20 of these. Although there are many analyses In this report -- Including the effects of varying air supply and heating rate -- a typical analysis comparing a pure resin and a wire and cable compound (51 per cent PVC) is shown In Table 2. Here we note the major constievents of Che combustion gases to be carbon dioxide, hydrogen chloride and carbon monoxide. The other gaseous components are mainly hydro carbons and the most abundant one Is- benzene. , We note that che hydrocarbons produced froa the compounds are much greater than that- froa PVC restn and this is attributed to the presence in thq^gases of breakdown material* froa the phehaiate plasti cizer. These latter are a series of hydrocarbons similar to chose produced by PVC. Hydrogen chloride 1q the gas reflects essentially complete conversion of Che chlorine In the PVC. The only other chlorine compounds reported in the gas ace vinyl chloride and methyl chloride In quantities less than 1 ag per gram of sample oxidized. Although detector* capable of measuring 0.1 ppm were used, no phosgefle was found. One of the more recent reports on PVC combustion studies ^vas made by W.( D. Voollayl? In 1971. In this work gases froa vdecomposition of PVC in air and nitrogen are analyzed by gas chromatography. PVC resin and unplasticized PVC sheet samples ''are compared and a special effort was made Co detect phosgene and ocher oxygenated organic compounds. Decomposition of the IS mg samples took place in a tube furnace at 300, 600, 450 and S00 (S72, 752, 842 and 932F) with a dry air or nitrogen flow of 100 mi per minute. Voolley essentially verified the gas analyses of Boettner** in that the organic components consist mainly of aromatic and aliphatic hydrocarbons. He detected approxieately seventy-five organic materials, about twenty-five more chan Boettner. Although the products are modified by the presence of oxygen, no oxygenated species were detected. Phosgene was particularly looked for and vas noC detecced. The organic gaseous decomposition products from PVC polymer were found to be similar in identity -- buc greater In quantity -- compared to those froa the rigid PVC sheet. This could be reflecting the difference in che resin content of the samples: 100 per cent for the PVC polymer and approxi mately 90 pet cent for the rigid PVC sheet. In 1971 Kobayashl and associates** reported on analyjas of combustion gases from PVC and PVC products in a comparative study with natural high polymer materials such as wood, paper, wool and silk. Their experiments were made by heating one gran saaples in an eleccrie furnace over a range of 300 to 700C (572 to L292P) through which air flowed at a controlled rate (1.01.5 liters per minute) and at no coal (21 per cent) and reduced (10.5 per cent) oxygen levels. The gases were analyzed by means of selected detector tubes. Following Is a quote froa the report: "As for the gas composition generating froa che PVC products at large, a major part consists of hydrogen chloride and carbon dioxide excepting hydrocarbons and water content, followed by carbon monoxide, but neither phosgene, chlorine, nitrogen dioxide, oxygen sulphide nor hydrogen sulfide were determined by the detector tubes.*1 Special effort was node to determine if phosgene were present In the combustion gases. The detection Halt vas determined to be 0.1 ppm. No phosgene vas reported in any of the combustion gases. } Carbon monoxide and carbon dioxide from combustion of natural polymers generally shoved up in the gases at lover temperatures and at higher levels than with PVC. This was 024 25266004 BFG39759 related co the easier Ignition of these ..oducts and the degree that hydrogen chloride docs not evolve with these natural polymers In comparison with PVC. In the comparison analysis with natural products, Kobayisht reported hydrogen cyanide In combustion gases from voolt and both hydrogen cyanide and atrcnonia In gases from burning silks. The mjximuar concentrations were reached at 400C (752F) and were as follows: wool -- hydrogen cyanide (1.2 per cent); silk -- hydrogen cyanide (0.36 per cent) and acsaonla (0.5 per cent). For comparison the maximum concentra tion of hydrogen chloride In gases from burning FVC products was froa 0.65 per cent at 5G0C (932F) for flexible auto cover leather to 12.0 per cenc at 400C (752F) for PVC resin. TOXICITY At the start we should recognize that the products of combustion of all organic products arc toxic and this includes wood, paper, natural fibers, etc. This is, of course, because of two main occurrences in a fire: production of carbon monoxide and dioxide and reduction of the oxygen concentration. The latter is cocsaon to all organic combustion and this includes PVC. Specific studies of the toxicity of gases from burning PVC have been conducted by various Investigators over Che yearsi?. The most recent was reported by Cornish and Abarl* of the University of Michigan* This investigation utilized the same samples of PVC as those described in the previously mentioned study of PVC combustion by Coettner^^. Ail animals exposed to the combuselon gases were male Sprague-Dawlcy rats. Autopsies were performed on all animals chat died. Cornish and Abar reported, "Without question, the major cause of death in this study of four polymers was the presence of relatively large amounts of carbon monoxide In the pyrolysis gas stream." They found relatively minor or no tissue damage in test animals exposed to hydrogen chloride froa PVC decosrposition. CONCLUSIONS1 2 3 4 1. phosgene and chlorine are not combustion products of PVC. 2. When PVC Is forced to burn, the prime products arc carbon monoxide, carbon dioxide, hydrogen chloride and water. 3. Minor gaseous products from burning PVC are aromatic and aliphatic hydrocarbons, predominantly benzene. 4. Carbon monoxide is the prime toxic component produced. 5. Hydrogen chlorlo .rom PVC pyrolysis or combustion Is essentially stotctilomecrIc. ACKNOWLEDGEMENT The author wishes to thank Mr. Llnuood B. Crider and Pr. Michael O'M.tra for their many suggestions and helpful contri butions In the preparation of this paper. REFERENCES1 11 1. HClado, C.J., Flammability Handbook for Plastics, Technotalc Publishing Co., 1969, p.39. 2. Fenloore, C.P. and Martin, F.J., Coabustion and Flame, 10, 1966, p.L35. 3. Fenloore, C.P. and Jones, C.W., Ibid, p.295. 4. Fenloore, C.P. and Martin, F.J., Mod. Plastics, 63, 1966, p.Hl, 5. Leamonth, C.S. et al, Br. Poly, J., 1^, July, 1969, p.l&9. 6.^Strombcrg et al, J. Polym. Set., 35, 1959, p.355. 7. Brad t, P. and Mohler, F.L., J, Research Had. Bur. Standards, 55, 1955, p.323. 8. Ohtanl, S. and Ichikawa, T., Kogyo Kagaku Zasshl, 65, 1962, p.1617. 9. Nofft, D., Benz. W., and Pfab, V., 2. Anal. Chen., 235, 1968, p.121. 10. O'ttara, M.M., J. polym. Sci. A-l, 8, 1970, p,l8ft7. 11. O'Kara, M.M., J. Polym. Sci. A-l, 9, 1971, p,1337. 12. Du four, R.E., Bulletin of Research No, 53, Underwriters* Laboratories, 207. East Ohio Street, Chicago, 111. 60611, 1963. 13. Linch, A.L., S.S, Lord, Jr., Kubtcz, K.A. and DeBrunnor, K.R., Amer. Ind. Hyg. Assoc., J., 26, 1965, p.465* 14. O'Kara, M.M., Crider, L.B, and Daniel, R.L., Amer. Ind. Hyg. Assoc. J., 32, 1971, p.153. 15. Tsuchlya, Y. and Suoi, K., J. Appl. Cheo., London, 1967, p.364. 16. Boeetncr, E.A., Ball, C., and Veiss, B., J. Appl. Polym. Sci., U, February, 1969, p.372. 17. Woolley, V.D., Br. Polym. J., 3, July, 1971, p. 185. 18. Kobayasht, Y., Kasahlro, H. and Murata, H., Japan Plastics, , January, 1971, p.40. 19. Cornish, R.H. and Abar, E.L. Arch. Environ. Health, 19, July, 1969, p.15. 25266005 Ft PURE t NEW YORK TI WES, OCT. 22, 1969 -- "NEW PLASTIC CAUSES AIR HAZARD" CINCINNATI POST, OCT. 31, 1969 -- "DISCARDED PLASTIC MATERIALS GUMMING UP INCINERATOR" . NBS NEWS RELEASE NOV. I 96*?---"HAZARDOUS PRODUCT PRODUCED BY ELECTRICAL INSULATION" INDUSTRIAL RESEARCH FEB. 1970 -- "DECOMPOSITION OF PVC YIELDS HAZARDOUS GAS" MODERN PACKAGING JAN. I 970---"PVC AND THE CYCLAMATE SYNDROME" DETROIT NEWS FEB. 2V, 1970-- "NEW PLASTIC IS TOXIC WHEN BURNED NEW YORK DAILY NEWS JUL. 16, 197!-"PLASTICS FIRMS SUE OVER TAX" C ! E NEWS NOV. 22, 1971 -- "PLASTIC CONTAINER TAX RULE0 OUT IN NEW YORK" 625 riuUKt i |> HOW POES PVC 3URN? 6 WHAT ARE THE MAJOR DECOMPOSITION PRODUCTS FROM PVC? |> WHAT ARE THE MAJOR COMBUSTION PRODUCTS FROM PVC? I> IS PHOSGENE A C0M3USTION PRODUCT? 0 IS CHLORINE A COMBUSTION PRODUCT? I) ARE THE COMBUSTION PROOUCTS FROM PVC TOXIC? BFG39760 FIGURE i 0 FIGURE 4 626 BFG39761 FIGURE 5 CONCLUSIONS PHOSGENE AND CHLORINE ARE NOT COMBUSTION PR00UCTS OF PVC. WHEN PVC IS FORCED TO BURN, THE PRIME PR00UCTS ARE CARBON M0N0XI0E, CARBON 01 OX IDE, HYDROGEN CHLORIDE AND WATER. MINOR GASEOUS PRODUCTS FROM BURNING PVC ARE AROMATIC AND ALIPHATIC HYDROCARBONS, PREDOMINANTLY BENZENE. CARBON MONOXIDE IS THE PRIME TOXIC COMPONENT PRODUCED. HYDROGEN CHLORIDE FROM PVC PYROLYSIS OR C0M3USTIQN IS ESSENTIALLY STOICHIOMETRIC. TABLE 1. PVC PYROLYSIS PRODUCTS OVERALL DEGRADATION' PROFILE . HCl Hydrocarbons Carbon Char % Wt. 58.3 37.0 4.7 HYDROCARBONS PROFILE. (Gas Chromatographic Area) ABLE 2. COMPARISON OF COMBUSTION PRODUCTS PVC RESIN VS . WLU U CAU1 -E COhlPOUND Tpolymlr 11 VS. PLASTIC G*i COMBUSTION PRODUCTS. mg/g Material PVC Resin Wire & Cable Compound (51% PVC) . HCl co2 CO Methane Ethylene Ethane Propylene Propane Vinyl Chloride l~Butene Butane Isopentane 1-Pentene Pentane Cyclopentene Cyclopentane 1-Hexene Hexane Methylcyclopentane Benzene Toluene Residue** 583 729 442 4.6 0.58 2.2 0.47 0.84 0.60 0.18 0. 28 0.02 0. 06 0.16 0.05 0.05 0.05 0.12 0.14 36.0 1.3 273 616 67 6.6 2.3 3.0 2.0 1.7 3.3 1.1 1. 1 0. IS * , 0.35 0.58 0. 14 0.16 0.24 0.49 0.14 10.0 0.94 159 * RE: Boettner et al, J. AppL Sci., 13, February 1969. p. 390 ** Residue is whit remained in combustion boat. CO Methane co2 Ethylene Ethane Propylene Propane Butane, butene C Butadiene, diactylen> Cc and C/ hydrocarbons Benzene Toluene Chlorobenzene Xylene AUylbenzene C9HI2 5"9HL2 Indane lndene y EthyltolueneJ Methylindane Methylindenea Dime thy lindane Methylnaohtha lene Methylnaphlhalene"? Acenaphtnalene J Run 1 0.6 8.8 0.4 3.5 4.8 2.9 3.0 ^* 1.9 51.2 5.3 1.1 1.9 1.3 0.4 0.2 0.2 0.9 0.5 1. i 4.8 0. 7 0. s 1.2 Area, % Run 2 2.2 7.8 0.3 3.5 S.l 2.6 1.9 2t 1 1.8 50.8 5.9 1.1 2.1 1.4 0.5 0.2 0.3 1.4 0.5 1* 3 4.6 0. 8 0. 7 1.0 Run 3 0.8 9.3 0.2 3.8 5. 5 3.0 2.3 ?| 1.3 50.1 5.8 1.3 2.3 1.6 0.5 0.3 0.3 0.9 0. S 1.0 4. 5 0,8 i.i RE: O' Mara. M. M.. J. Polym. Sci. A-1, 8, 1970, p. 189 627 400998SZ BFG39762 KiS SKiUi KT'At- 15 Toxicity of criftiui in ruts exposed to the pyrolysis prod ucts of polyurethane foam. The quantity itpriw;*, H.M.! Pyrolysis Products ofiu*U I'x* f foi lta- (fOl .'iMSiMJV' 1-TNl`l. / kS~UI Vinyl Plastics :*k of Analytical Chctnis. ill Hook Co.. liktt. Jo Tests for Mcvfuty u Herbert ll. Cornish, 1`ltl). and .Amor J Clin Uvhni- Ellen L. Abar, MA, Ann Arbor, Mich ;*V7. K;v\v;mish* HSntlttuuTv*. nonstmiion of Imnwctlula; Polyvinyl chloride polymers and formulations ell* of l*aucro;\tio Tsloi.s were pyrolyzed in a stream of air by gradually ;o. 3> uxw. troa Micros'copit'til Ixv al'u -iippoosmvpal Moswy Kilw* raising the temperature from ambient to approxi mately 600 C. The pyrolysis air stream was diluted Sulfide Silver VrococUirc. with twice its volume of room air, and rats were 1967. exposed to it. Exposure to an air stream con and nature, of pyrolysis products of Teflon depends on degradation temperature. V.',ar il/. and Kwon' reported no adverse effects in rats exposed to products of Tc-fion heated to 400 C, while pyrolysis at 450 0 producr-fi acute pulmonary hemorrhage and edema. Coleman ct al- suggest that at 550 to 700 O, carbonyl fluoride may be a major toxic product of Teflon degradation. MacFarland and Leons'5 -studied the tox icity of pyrolysis products of polyurtthancand polyurethane-coated nylon. Acute as phyxia from occlusion of the upper re spiratory tract was apparently the mechanism :ructun.\l Localization of taining the pyroly2ed products of 1 to 2 gm of of death of animals exposed to pyrolysis inert Sulfide-Silver Method, polyvinyl chloride polymer resulted in the death products of polyurethane, whereas with ny iJuhe 2S) 1967. of 50% of the animals. Most deaths were due to mrr. S.: Trials to Modify carbon monoxide (CO), and carboxyhemoglobin I for Cltrastrueuirnt Tiviw Metals, Acta Hisioehrn. (COHb) levels correlated well with the amount of plastic pyrolyzed. Little histological evidence 7.E.: and I'ratt. R. of lung damage was evident. When oxygen (0:) imvnca 1955 Edition. oil 25, was added to the air stream to prevent deaths neett Co.. I960, p 62:!. from CO, pulmonary edema and interstitial hemor lon -products, death occurred from slowly developing pulmonary edema. Thrune7 re ported the chemical analysis of products of combustion of halogen containing epoxy re sins, while Leong and MacFarland' reported on the hazards from thermodecoreposition of Physicochemical Ration:.!? rhage developed. The lungs of some animals epoxy resins. On the basis of animal studies city of Mercury and lt exposed to high levels of pyrolysis products of- . they suggest that pyrolysis products of epoxy cad Set 65:454-400 (April) vir.yl chloride-vinyl acetate copolymer also showed resins may constitute a hazard under cir focal edema and intra-atveotar hemorrhage. Poly rication by Mercuric Cnlo. Photo J 50:2oS-24i> (.June;. vinyl chloride formulations, containing additives and inert materials, v/ere in general less toxic per :.r 'roprobe: Its U.-o for gram of sample pyrolyzed. tis. mistrv. J Histnchem ov) 1906. Tc al: The Localizaiicu of c.crcd Radioactive Mcnruy HE WIDESPREAD use of plastics in cumstances realizable in practice. Boettner and Weiss9 described an analyt ical system for identifying the volatile pyrol ysis products of a virgin homopolymer polyvinyl chloride (PVC) resin. In another study, Boettner et al10 noted that three distinct breakdown temperature ranges oc Jltrcstruct Res 3:23>S .Dec: the manufacture of commercial and house curred as temperature was increased. The hold products raises the question of poten pyrolysis products released during these ai. T.: and Nakao, K.: Div tial hazards associated with burning these the Brain and Its Subvetlutal Organic Mercury Poison- materials. This is not a new problem; it was .57-406 (May) 1960. investigated by Berger et al1 in a study of Intracellular Distribution of thermosetting plastic materials used for in three weight loss periods differed markedly. The present study is an extension of their work to include toxicological investigations of the pyrolysis products of polyvinyl chlo After Methcxycthylmeivurj sulating electrical conduits. They deter- ride plastics. The samples and samole desig r.crmacol I6:.i6io-io.>; (Sept; m;necj gQmg products produced during pyrol- nations are those of Boettner et al.ir' Iatraceiluiar Distribution o! 'J*is of Phenolic and melamine plastics-- After a Single Injection ' carbon monoxide (CO), cyanides, and am:chrm Pharmacol 17:551-591 monia. Watson et al2 reported the chemical identification of pyrolysis products of foamed polyvinyl chloride, Zapp's* investi gations revealed pulmonary congestion and now society in general eir responsibilities.. In . S.S.: Our Changing ractice, Amer J Public Submitted for publication Dec 26, 1968; accepted Inn 20, 1969. l-Yon: the Department of Industrial Health, S-liool of Public Health, Ann Arbor, Mich. 'Reprint requests to 3616 School of Public Health. University of Michigan, Ann Arbor. Mich 48104 (Dr. Cornish). Materials and Methods Materials.--The materials consist of four pol ymers produced by two companies and three formulations which utilize three of the poly mers. The materials were classified as follows. Sample A. A polyvinyl chloride horr.opolymer in which approximately 20% of the parti cles fall within the range of 100^ to 250.-, with most of the remainder falling below lOO.u in size. Sample B. Similar to A but of somewhat Arch Environ Health--Vol 19, July 1959 BFG39763 16 PYROLYSIS PRODUCTS--CORNISH & ABAR i ! py smaller particle size, with 85% of the particles within the 75m to 200m range, and the remain der betow 75m. in the boat and combustion tube was weighed at the end of the exposure to determine the extent of pyrolysis. Periodic measurements of i Table 1.-- Effect c Sample C. A polyvinyl chloride homopolymer (powder) produced by a different company. Sample D. A copolymer of vinyl chloride hydrochloric acid (HC1) and CO were made Quantity Pyro'yztrS ; (grr) Weight of Residue (S'*) Exo: (r and vinyl acetate (powder) in the approximate pump and detector tubes. Unfortunately. HC1 ratio of S5:15. detector tubes did not go above 500 ppm. Pre ; 0.8 <0.01 1 Sample E. A formulation commonly used in vious studies by Boettner et aid however, ( electrical wire insulation utilizing polymer C show that HCl is released over a relatively (smalt cubes, approximately 5 mm). short time during pyrolysis. Thus, maximum 1 Sample F. A formulation commonly used for concentrations can he estimated with a fair ! 1.0 <0.01 1 floor tile utilizing copolymer D (fluffy powder degree of accuracy. - containing asbestos). In early studies the level of HCl in the air t ' Sample G. A formulation commonly used in leaving the-exposure chamber (desiccator) was * 1,2 ; wire insulation utilizing polymer B (sheets cut into approximately 5-mm cubes). Animals.--All animals included in the pres ent study were male Sprague-Dawley rats. The . 1.4- <0.01 animals ranged in weight from 200 to 300 gm lized. Plastic baby bottles, attached to small and were maintained on an ad libitum diet of commercial rat chow and water except during the exposure periods. At autopsy, animals were type of exposure .'eliminated the absorption o: 1.5 0.03 anesthetized with ether, and blood was removed HCl. and possibly other vapors in the urine by heart puncture for the determination of which accumulated in the bottom of the small -Animal deaths. carboxyhemoglobin (COHb) and other blood chamber. It also prevented animal crowding Numerator, deaths: dene studies. In most cases, blocd was also obtained and the adsorption of pyrolysis products on . for COHb measurement in animals dying dur- animal fur. Hydrochloric acid" and CO concen- anirna ? under these 'ing the exposure periods. In some cases, blood trations were measured in samples taken front ` LC-,,' was approxirr for COHb determinations was obtained from the moving air stream. -n tall exposures, anin the tail vein. Tissues were promptly removed Blood Analysis.--Blood carboxyhemoglobin of nasal and eye irri and small sections fixed in 4% formaldehyde was determined by the micro-method of Scho- charge, salivation, an and stained with hematoxylin and eosin. Ani lander and Roughtonu-and was always done in Convulsions were a < mals surviving the exposures and not killed duplicate or triplicate. Serum glutamic oxalonc- animals with high were maintained for a minimum of two weeks etic transaminase (SGOT) was determined by c;fnce work o* and observed for latent effects. the method described by Steinberg et alT that j Exposure Techniques.--'The exposure cham ber utilized in early studies was a 7-liter desic cator with the animals maintained on a grid 4 to 5 cm above the bottom. Four rats were normally exposed at one time. The weighed Hemoglobin levels were measured spectropno- m-m - , ,. , .tomo.tn. ca,,lly .in d..i.lut.e ammoni.a. PVC at relativelv i . rnals were exposed n -_ ,, ResuIU : earlv pvrolvsis prodi : Pie" A." and remove. plastic was decomposed in a ceramic boat placed in a combustion furnace programmed for increasing temperature (three degrees per minute). This programming technique was re cently described by Boettner and Weiss. TemP'-r.iture was measured in the combustion boat by a thermocouple and reached a maximum of 550 C after 115 to 140 minutes at which time pyrolysis was essentially Complete. Animals were remov'd at or near the end of this time period unless death occurred earlier. Daring pyrolvsis. 2 cu ft of air per hour passed over the plastic. The pyrolysis stream was cooled a rid dilut'd by the addition of 1 cu ft of air per hour prior to entry into the animal chamber. Temperature in the animal exposure chamber did not rise above 29 C. with an average of 27 ('. The ash remaining in the ceramic boat or The results of vf,.asra'yminpg,le aA.m). ouanrt*cs .st,hhooerf wfnmPirVs.imtnCs,,Ttua,hdob,vvmleoup' 1toi.lilivz7minhcger animals w-ore exposed in a 7-liter dessientor. e_u_x_pr_ot_seKd.illeadni.m.i-a* l,shosui:: toss during the expc not completely res: Note plete, that pyrolysis was and that quantities essentially com of ash reinnininc day. v-cre Liver and kid not significant! in the ceramic boat were negligible. Al animnl^Hematoer though the level of CO in the air was greater than 3.000 ppm for some time dur ing each of the exposures, the COHb level? varied greatly among the different groups However, the COHb levels correlate well tcred, Q^jr were St utilizetKjis a men: Histon^gjyolocicnl c T kiritfy. and splr bctwee(Q>.\posed ar with the amount of plastic pyrolyzed. T'.xposores to increasing amounts of sample A demonstrate this correlation. The quantity la were nose .ifjl subseque (fiOoscri by ; into the pyn of pyrolyzed plastic which killed 50'','. of the scribed in the mod Arr/i llrwirnn H'-nllh -- V<il 19. July I9G9 BFG39764 rviu,,.vsis i'i:oi)Ucrs--C()i:\'isii x- a hah 17 utu' u"is weighed ; to determine the ; miMsuronu'iits of C" vere nwilr ; iii ants of tlio a pas sim|>linp Table 1.--Effect of Pyrolysis Products of Polyvinyl Chloride Homopolymer (Sample A) Quantity pyrolyzed ls.m) Weight of Residue (Rf"> Exposure Time (min) CO Max Cone (ppm) Rat No. Blood Ht> (gm/100 cc) COHh (vol %) Mcrtalit-/t iforuma'.i'ly. IH'1 vo MX! ppm. l're- ' 0.8 <0.01 130 >3,000 10-15 min t al."' however, over a relatively Thus, maximum atod with a fair ; 1.0 <0.01 135 >3.000 10-15 min i ? :< 4 i 2 3 4 1C.2 15.3 10.2 17.1 15.3 15.7 ie.i IS.2 14 14 0 54 8 15 71 38* 4 8 if HCl in the air {desiccator) was : itoring the chamstudics, exposure irtimal's nose prostfeam were utiittached to small large vinyl tubing was passed. This the absorption of xirs in the urine ittom of the small animal crowding >3.000 1.2 135 15-20 min 1.4 <0.01 125 >3.000 15-20 min 1.5 0.03 120 >3,000 15-20 min Animal deathsi Numerator, deaths; denominator, total. i 2 3 4 i 2 3 4 i 2 3 4 15.3. 16.2 15.0 15.7 17.6 16.6 16.6 15.7 65* 78* 11 65 65* 19 55* 68* 42* 55*. 40* 45* 2 4 3 4 4 4* lysis products on d and CO coneenmiples taken from animals under these exposure conditions LC;..,) was approximately 1.2 gm of PVC. In all exposures, animals showed symptoms The results of exposure of animals to PVC homopolymer B is shown in Table 2. All animals exposed to 0.8 gm of pyrolyzed arboxyhemoglobin of nasal and eye irritation with nasal dis plastic survived. Maximum COHb levels -j-method of Seho- charge, salivation, and chromodacryorrhea. were 17 and 21 vol% in two of four rats. At ,as -ilways done in , ^ Tiic oxaloacvas -etermined by Steinberg et al.i: tsured spectrop'no- nia. Convulsions were a common occurrence in the animals with high COHb levels. Since the work of Boettner and Weiss had indicated that HCl was released from PVC at relatively low temperatures, ani mals were exposed in the desiccator to the 1.2 gm of plastic, one animal with 66 vol% COHb died. The surviving animals had con siderably lower COHb levels. At 1.4 gm, three of four animals did not survive the exposure. The single surviving animal again had a relatively low COHb level of 13 early pyrolysis products of 2.0 gm of sam vol%, as compared with 65 to 75 vo!% in ple A, and removed before they became n fleeted by large quantities of CO. Animals t study utilizing were killed 24 hours after exposure. The 'C homopolymer exposed animals suffered a slight weight In Table 1. The lass during the exposure period which was 7-liter dessicator. not completely restored by the following essentially com- day. Liver and kidney body weight ratios of ash remaining were not significantly different from control e negligible. Al animals. Hematocrit values were not al in the air was tered, nor were SGOT levels which were >r some time dur- utilized as a measure of tissue damage. the COHb levels Histopathological examination of lung, liv different groups, er, kidney, and spleen showed no differences els correlate well h'tween exposed and nonexposed rats. : pyrolyzed. Expo- In all subsequent studies, the animals mts of sample A were exposed by the insertion of only the on. The quantity nose into the pyrolysis air stream as de killed 50% of the scribed in the methods. the other three animals. An attempt was made to overcome the acutely toxic effects of CO and possibly allow other aspects of toxicity to become evident. Animals were exposed to PVC pyrol ysis products as previously described with air passing over the sample at 2 cu ft/hr, but with replacement of the air dilution stream by oxygen (4 cu ft/hr). In separate studies, 3.5 gm of samples A and B were pyrolyzed and animals exposed to the pyrol yzed air streams. All animals survived these exposures which, without oxygen (0.0 would have been lethal. Calculations of HCl re lease would predict levels above 6,000 ppm for 15 lo 30 minutes during this exposure. Animals were killed 24 hours after expo sure and lung tissue taken for histopatho- Arch Environ Health--Vol 19. July 19C9 0T099ZSZ BFG39765 18 ( \ PYROLYSIS PRODUCTS--CORNISl-li ADAR Table 2.--Effect of Pyrolysis Products of Polyvinyl Chloride Homopolymer (Sample B) and Formulation (Sample G) Table 3.----- Quantity Pyrolyzed (S'11) Sample B 0.8 Weight of Residue (gm) <0.01 Exposure Time (min) 130 CO Max Cone (ppm) >3.000 1.2 <0.01 1.4 <0.01 Sample G 6.0 0.93 130 130 105 >3.000 5*10 min >3.000 10-20 min 800 Rat No. Blood .------ j--------------- ------------------- -----. :'Hb COHb (gni/100 cc) (vol Quantity 'yrolyred (8rr\) Mortal:!; 1 17.1 17 1.2 2 16.2 21 0_ 3 15.7 74 4 13.7 5 1 17.1 66* 2 16.6 19 1.5 3 15.3 94 4 17.1 11 1 16.6 74* 18 2 14.5 68' 3_ j 3 15.3 13 4 : 4 ___________170___________. 69* ____________ ; 1r riTo ~7 i 2.i 2 15.3 7 0! 3 12.0 A 9 4 <5 ' V.'el^t Res.S. <0.0 0.0 <o.c ` Animal deaths. (Numerator, deaths; denominator, total. logical examination. Of the animals exposed D with COHb levels of 12.3 to 14.5 voI?iCon,-fo!s to sample A, all showed evidence of pul These COHb levels do not appear to b "Animal deaths, monary edema and intra-alveolar and inter high enough to be responsible for the death `Nurnera stitial hemorrhage. Several of the hemor which, occurred during and shortly aftolungs of expo rhages were associated with angular fibers exposure. SGOT levels of all rats exposed ijto controls. and sheets of foreign material within the 2.0 gm were slightly elevated, suggestive d Three of fc alveoli. Examination of the lungs of animals tissue damage. the pyrolysis exposed to sample R revealed pulmonary Histological sections of lung, liver, nr formulation. ( edema and interstitial hemorrhage, hut no kidney or all miinmls exposed to 2.0 gm cj.ind two <>lh traces of foreign material. product were not different from those c hours, ('arise Sample C is a PVC homopolymer pro control animals. The lungs of some but ml high as 30 v duced by another company. The results of all animals exposed to 2.5 to 2.S gm cirats exposed exposure to the pyrolysis products of this pyrolysis product showed focal edema wiiigm of PVC f< material are shown in Table 3. Exposure areas of acute suppuration and occassiorJately after ex ranged from 1.2 gm where all animals sur intra-alveolar hemorrhage. jfor histopatl vived, to 2.3 gm where all animals died. In Sample E is a formulation of polymer Qwas no evict general, COHb levels correlate well with the commonly used in wire insulation applied exposed grou degree of exposure and the mortality data. tions. The results of this study are shown a Sample F. The acute LCSn under these conditions is Table 5. Even at levels as high as 3.0 gm cj tion of samp approximately 2.0 gm of pyrolyzed plastic. formulation, CO levels did not reach l,0C\jof inert mate Surviving animals were killed 24 hours af ppm in the air stream, compared with vs!`6.0 gm of t! ter exposure. Tissues of exposed animaLs ucs as high as 3,000 ppm with 1.2 gm cl total residue were comparable to control animals. Serum homopolymer. Hydrochloric acid levels iijof the origu SGOT levcLs, however, showed some eleva the 4.0-gm sample air stream were in exces* 1.4 gm of tions suggestive of tissue damage. of 500 ppm. All animals survived exposure posed. All The results of the exposure of animals to ranging from 3.0 to 4.0 gm of pyrolyzed vol%. The the pyrolysis products of the vinyl chloride- material. Carboxyhemoglobin levels did not after expo; vinyl acetate copolymer (sample D) are rise above 23 vol% in any of the exposed lungs and S shown in Table 4. The pyrolysis of quantities animals, and no animals died during tW controls, greater than 2.0 gm resulted in deaths of exposure period. Animals not killed for The pyrol animals even though they had relatively low COHb levels were maintained for 2-1 hours (wire fomm COHb levels. Rats died after exposures to then killed and examined for histological the lb rats pyrolysis products of 2.5 and 2.R gm of sample evidence of lung damage. In all cases, th4 cal cvicienc Arch Environ. Health--Vol J9, July I9G0 BFG39766 i C/1 N <?, o 1 PYROLYSIS PRODUCTS--CORNISH & A BAR 19 2 3) and Table 3.--Effect ol Pyrolysis Products ot Polyvinyl Chloride Homopolymer (Sample C) Quantity pyrolyred (am) Weight of Residue (gm) Exposure Time (min) CO Max Cone (ppm) Blood Lung Rat Hb COHb <%> SGOT No. (gm/100 cc) (vol %) (Body Weight) (units) MoftalityF ) Morality 4 1.2 1.5 <0.01 0.02 2 15.0 7 130 >3,000 2 3 15.0 16.2 0 0 ... 4 14.1 0 1 20.4 30 0.38 135 >3.000 2 3 12.3 13.7 64* o.3e 42 0.47 4 14.5 24 0.46 0 ... 4 69 127 124 1 4 1.8 ... 1 15.3 42 0.50 99 135 >3,000 2 3 15.7 14.5 28 38 0.51 0.58 132 123 0 4 4 15.0 15 0.47 109 1 13.7 46* 0.41 ...2.1 <0.01 130 >3.000 2 3 17.6 17.5 21-44* 0.47 0.50 2 3 1 16.2 . 41* 0.50 134 2.3 0.02 135 >3,000 2 3 15.3 * 15.3 30* 39* 0.50 0.56 103 4 7 4 15.7 61* 0.52 1*64 to 14.5 VOlft Centrals G rats 0.53 67 appear to b for the death Animal deaths. INumerator, deaths; denominator, total. shortly affc lungs of exposed animals were comparable these animals. The results of the exposure ats exposed: to controls. to pyrolysis products of 6.0 gm of sample G . suggestive c Three of four rats died when exposed to are included in Table 2 since this is a the pyrolysis products of 6.0 gm "of this formulation of sample B. Even at this high n? liver, ar. formulation. One died during the exposure level of exposure, no animals died and all i .0 gm c and two others died within the next 16 COHb levels were below 10 vol%. from those c hours. Carboxyhemoglobin levels ranged as ' some but r.c high as 30 vol%. An additional group of Comment to 2.S gm c rats exposed to the pyrolysis products of 6.0 The toxicological findings in pyrolysis al edema wh gin of PVC formulation were killed immedi studies will depend, to a large extent, on nd occassiom ately after exposure and lung sections taken methodology. This'includes such factors as for histopathological study. : Again, there presence or absence of oxygen during com of polymer ( lation applic y are shown: ;h as 3.0 gm t .ot reach 1,0: >ared with vc. vith 1.2 gm c acid levels i were in cxce ,-ived exposun i of pyrolyzc j levels did r.: of the expos; fed during t not killed ! ;-d for 24 hou: :or histologic, n all cases, : was no evidence of lung pathology in the exposed group of animals. Sample F, which is a floor tile formula tion of sample D, contained large amounts of inert material. Pyrolysis (up to 550 C) of 6.0 gm of this material (Table 4), left a total residue in the boats of 4.6 gm of 76% of the original material. Thus, only about 1.4 gm of material was actually decom posed. All COHb levels were below 5.0 vol%. The animals were killed 24 hours after exposure. Histological sections of lungs and SGOT levels were comparable to controls. The pyrolysis of 1.2 to 2.5 gm of sample G fwire formulation) produced no deaths among '.he 16 rats used in these studies. No histologi cal evidence of lung damage occurred in bustion, air flow rates, dilution of pyrolysis stream, presence of particulates, and type of exposure chamber utilized. In spite of the variables involved, certain valid compari sons can be made utilizing standardized conditions of pyrolysis and exposures. In several of the early studies described here, animals were exposed in a small desic cator in which urine and feces accumulated during the exposure period of one to three hours, and vapor collected on the chamber walls. Measurement of HC1 gas at the inlet and outlet of this chamber indicated a con siderable loss of HC1 as the air stream passed through the chamber. Although most of this loss may have been due to solution in liquid, some may also have deposited on the animal's fur. Subsequent studies utiliz- * Arch Enuiron Health--Vol 19, July 1969 j: 66012 BfG39l61 < 20 PYROLYSIS PRODUCTS--CORNISH'& ABAR I Table 4.- -Effect of Pyrolysis Products of a Vinyl Chloride-Vinyl Acetate Copolymer (Sample D) and Formulation (Sample F) i '"Qua ntity Pyrolyzed (gm) Weight of Residue (Sm)* Exposure Time (min) CO Max Cone (ppm) Blood Lung Rat Hb COHb ((%%>) SGOT No. (gm/100 cc) (vol %) (Body Weight) (units) Mortality; Quantity Pyrolyzed (gm) We R- r Sample 0 2.0 0 2.5 0.16 8,000 1 12.0 112 >3.000 5 min 2 3 4 13.7 15.3 14.3 ...1 13.3 103 >3.000 5 min 2 3 4 14.5 12 0.57 18 0.58 12 0.56 8 0.52 56f 0.60 13t 1.38 cyst 2 It 0.53 54t 0.48 100.5 84.0 143.5 135.5 ... ... 4 4 4 4 3.0 c 3.6 c ...2.8 0.10 105 7,000 >3,000 S min 1 2 3 4 14.1 13.0 12.3 32 0.53 sot 0.60 ...t 0.58 61t 0.99 1. 4 4.0 c Sample F 6.0 4.6 130 >3.000 S min i 2 3 4 14.5 14.1 15.3 15.0 ` 5 5 5 5 0.48 0.55 0.50 0.52 80 55 0 72 4 56 6.0 l Controls 12 rats 'Residue in boat plus residue in combustion tube. Animal deaths. tNumerator. deaths: denominator, total. 0.60 67 6.0. Control 1 ing an air stream Into which only the ani- large amounts of pyrolysis products, the mal's nose protruded overcame these diffi animals died quickly due to carbon monox culties. ide poisoning, thus the effects of HC1 could tARnct*m*aJul cclea^t* ^Numerator. < Without quostion, the major cause of not be demonstrated. However, when ani exposed anir death in this study of four polymers was the mals.did survive exposure to lesser amounts be pvrolvzc presence of relatively large amounts of car of pyrolysis products, tire histopathological COHb levels bon monoxide in the pyrolysis air stream. findings in the lung were not remarkable. In Three P The blood carboxyhemoglobin levels, in the two studies where sufficient O- was , studied. The general, correlated well with the amount of added to the airstream so that animals did sample E co pyrolyzed PVC. However, rather marked not succumb to CO effects, pulmonary ede much chlori exceptions occurred within groups. For ex ma and interstitial hemorrhage were noted homopolym? ample, in three of four rats exposed to 1.2 in all anipnals. In one instance, this was about 50% gm of polymer A, COHb levels were above associated with the presence of angular The analytic 65 vol%. In the fourth rat, the blood COHb fibers and sheets of foreign material within much CO w level was only 11.4 vol%. Other similar the lung. No attempt was made to remove In the prise irregularities can be noted throughout the particulate matter from the air stream. Per amount of a study. When animals were exposed in a haps in this one instance, a sudden erup produce unu desiccator chamber, it was felt that animal tion of material from the pyrolysis boat exposed ani: crowding might have played a role in these could account for the findings of particulate 6.0 gm of P\ inconsistent findings. However, similar matter in the lung. imum CO He findings will be noted in the subsequent The lungs of some animals exposed to 2.5 posed anin:3 studies when only the animal's no.se was to 2.8 gm of pyrolysis product of copolymer j^of 24 to 64 \ exposed to the air stream. Perhaps a partial D showed focal edema with several areas of ij"gm of. the he explanation may relate to the animal's re acute suppuration and occasional intra-al- tfour animals spiratory rate at the time of high CO levels veolar hemorrhage. It is interesting to note ^ologieal stud in the air stream. This period of high CO that the analytical data of Boettner et al"' ^exposed gro; levels was relatively short compared to the indicate that this pyrolyzed sample (D) has jtrots. thus t total exposure time, CO levels being greater HC1 concentrations quite comparable to ')w4iParent. Anox than 3,000 ppm for less than 20 minutes samples A. B, and C, but CO production is u gospasm. cou during most exposures, and in some eases such levels may have been reached for only a few minutes. With exposure to relatively approximately one half that of the previous samples. Thus in this instance the irritant effects of HC1 Incomes more pronounced in This; invt>::. _ He Hciiith St. CV Tcvhnkwl Hull. Arch Environ Health--Vo! 19, July J9G9 BFG39768 ( .noi.vsis niourcrs -coHNtsif & ai.ai: 21 olymet (Sample D) and Tabic S--Ellect ol Pyrolysis Products ol Sample E (Formulation of Sample C) ---------------------------- - Quantity r. - PyrolyieU 1) SCOT ., (units) Mortality; UTM) ~7 To Z. 1 60 cyst 53 4S 100.5 S4.0 143.5 135.5 ... ... 0 4 -- . -i 4 3.0 DO 60 ... 53 . . 55 ... 3_____ 4 4.0 43 60 55 55 0_ 6.0 50* 72 4 52 56 50 67 6.0 Weight of Residue (gmp 0.70 0.9S 0.96 1.20 1.19 Exposure Time (min) 135 135 135 140 137 CO Max Cone (ppm) 850 10*15 min SM) 10-J0 min 2.000 3*5 min 2.000 5-10 min 3.000 few min Rat No. i 2 3 4 t .* J 4 i 2 3 4 i 2 3 4 i .2 3 4 OloorJ Mb (gm/100 cc) 13.3 12.3 13.3 Ml ;.:.3 l 12.7 COHb SCOT (vol %) (Body Weight) (units) 17 0.57 11 0.57 18 0.55 12 o.:4 83 74 IOO \o\ ft V 40 / U.`.l> 7 0.51! 9 0.54 111 fir. Hi 15.3 23 0.50 14.1 7 0.54 14.5 2 0.53 11.7 4 0.55 87 67 83 93 16.6 14.5 18.1 18.1M 20 301 71 241 0...7.5 0.43 .9.8. 17.1 15 0.51 81 14.1 11 95 13.7 20 0.51 72 13.7 10 0.57 151 Mortality: 0 A O 4 A 4 -# %* Killed Control 8 rats 0.54 59 vrolysis products, the Residue in boat plus residue in combustion tube. due to carbon monox- tAnimal deaths. ^Numerator, deaths; denominator, total. ie effects of HC1 coulc References i. However, when ani- exposed animals since larger quantities can jsure to lesser amount be pvrolyzed without producing lethal 1. Berger, T-, ct al: Toxicity and Flame ftesistar.ee of Thermosetting Plastics, report 4134, US Dept of the Interior. Bureau of Mines. Oct 19-17. the histopathologic^ COHb levels. rere not remarkable. It Three PVC formulations were also .ere sufficient 02 wa studied. The analytical data0 indicated that 2. Watson, H-, et al: Thermal Decomposition Products and Burning Characteristics t,j Some Syn thetic Low-Density Cellular Materials, reper: 4777. US Dept of the Interior, Bureau of Mines. 1051. it that animals die sample E contained approximately 50% as ene. pulmonary eae- much chlorine per gram as do the PVC lemorrhage were notec homopolymers, indicating the presence of 3. Zapp, J.A., Jr.: Hazards of Isocyanates in Polyurethane Foam Plastic Production. Arch Jr.dustr Health 15:324-330 f April) 1037. 4. Waritz, R.S., and Kwon, B.K.: The Inhalation me instance, this wa- about 50% of materials other than PVC. Toxicity of Products of Polytet.-aduoroethyler.e presence of angular The analytical data also indicated 30% as Heated Below 500 Degrees Centigrade. Am.er Industr Hyg Asfoc J 29:19-26 (Jan-Feb) 1968. foreign material withir. much CO was produced from this sample. 5. Coleman. W.E.. et al: The Identir.caticn o: r was made to removt In the present studies, doubling the usual Toxic Compounds of Polytetrafluoroeihy'.er.e <PTFE), Amer Industr Hyg Assoc J 29:33-40 nm the air stream. Per- amount of material to be pyrolyzed did not (Jan-Feb) 1968. nance, a sudden erup produce unusually high COHb levels in the m the pyrolysis bos exposed animals. In fact, the pyrolysis of findings of particulati 6.0 gm of PVC formulation resulted in max 6. MacFarland, H.N.. and Leong. K.J.: Hazards From the Thermodecomposition of Plastics. Arch En viron Health 4:591-597 (June) 1962. 7. Thrune, R.I.: Cases Released When Fire Re imum COHb levels of 30 vol% in the ex animals exposed to 2f posed animals, compared with COHb levels i product of copolyme of 24 to 64 vol% after pyrolysis of only 1.5 .a with several areas o gm of the homopolymer. However, three of ,nd occasional intra-ai four animals in this group died. Histopath- sistant Epoxy Resins are Burned. Am.er Industr Hyg Assoc J 24:475-480 (Sept-Oct) 1963. 8. Leong, K.J., and MacFarland. H.N.: Hazards From Thermodecomposition of Epoxy Resins. Arch Environ Health 7:675-681 (D:-c) 1963. 9. Boettner, E.A., and Weiss. B.: An Analytical System foe Identifying the Volatile Pyrolysis Prod I: is interesting to not ological studies showed that the lungs of the lata of Boettner et al: exposed group were not different from con rolyzed sample (D) ha trols, thus the cause of death is not ap ucts of Plastics, Amer Industr Hyg Assoc J 23:535540 (Nov-Dec) 1967. 10. Boettner, E.; Ball, G.; and Weiss B.: Analy sis of the Volatile Combustion Products of Vinyl quite comparable r parent. Anoxia, resulting from irritant larynl, but CO production i gospasm, could be a factor in these mortalities. Plastics, J Appl Polymer Science, to be published. 11. Scholander, P.F.. and Roughton. F.J.W.: Sim ple Micic-Gasometric Method of Estimating Carbon alf that of the previoc This investigation was supported in part by pub* ;is instance the irritar. ne= more pronounced i: lie Health Service research grant UI-00485 from the National Center of Urban and Industrial Health. Tocimioal assistance was given by Gwendolyn Monoxide in Blood, J Industr Hyg Toxic 24:215-221 (Oct) 1942. 12. Steinberg. D.. et al: A Clinical Method for the Aassay of Serum Grutamic-Oxalaccttc Transaminase. Hall. J Lab Clin Med 48:144-151 (July) 1956. Arch Environ. Health--Vol 19, July 1969 C;i a o H- BFG39769 ............. i