Document wDNn1GGLpq0Yo9NRxz7gwKoEJ

'5(S*, In the fatalities due to CO, average concentration of CO tj^Vj <; - ] bui 45%. The burning of cellulose mat*;''' v'to teX rial resulted in nothing but the ra; lease of CO. In the mouse study -Ms of exposure to burning building matA&j rials, the ECG abnormalities w*|^*> hiu recorded before the arooke from they t foa burning materials was evident. 4'M- ' OOl In regard to the harmful properties** 'ter of PVC to mice, as well as those frog'll polyurethane, polystcrene, and pha V phi 'str nol, the pathologic effects of the'jfi 1. thr gases, rather than those of the smoke; J ' de-f appeared first, ae shown by atypicaft,; ;, ,-tur ECG changes. It requires less CO in #3 'of combination with HCI to cause deatlk 't "wh In conclusion, HCI and CO have a rv`:ij j -fig* ciprocal, potentiating advene effect./'^ V rat EFFECT OP SMOKE . j C' j [, . * ' Smoke is a suspension of small par- .V tides in hot air and gases. It has,./ a particulate fraction and'a gaseous1'1', fraction. The particles consist of car .3 bon and are coated with combustible . < products such as organic acids and al-"-,, dehydea. The gaseous fraction has an /{, pa' . tai "ins alt .' det - the Ufe extremely variable composition. Car- i Fig 1 .--Hydrogen chloride concentration and optical density ol polyvinyl chloride eleetrir cal inaulation decomposition products.' ; the respiratory tract An HC1 concen tration of 15 ppm causes localized irritation to the throat after short ex- posure. Hydrogen chloride concentra tions of 50 to 100 ppm are tolerable for one hour by humans. More severe exposures result in pulmonary edema formed at the Univeraity of Tokyo. ' With respect to the toxicity of carbon monoxide. Kishitani states that the injurious nature of PVC is unique. All mice exposed to harmful gas products died, but the carboxyhemoglobin con centration in the dead animals was bon monoxide and carbon dioxide are always present and constitute the j bulk of this fraction. However, a wide variety of other toxic gases are present at the scene of a fire. These may be formed by the combustion process or leak from1 com mercial processing or storage equip ment The particulate and gaseous fractions combine to exert a large . space-occupying effect and can fill an . 'Vb' an tor th; V ".sul ; fic. ;ar ,an . qc and often in laryngeal spasm. Con centrations of 1,000 to 2,000 ppm of low (average, 21.2%). This clearly in endosed space at the expense of air. ' dicated that the fatalities were not The gaseous fraction of smoke is ft HC1 are dangerous even with brief exposure' (Fig 1). Quantitative release of HQ on due directly to CO poisoning. At autopsy, the eyes of the mice were dosed, their mucous membranes were much more dangerous to life than the particulate fraction. The nose, mouth, and throat which filter out and trap .dfli tit; :'Ll thermal degradation of PVC has been injured by chemicals, and the sclerae the particulate fraction, cannot filter ; Ti well documented in the scientific and were discolored. The latter had be out the toxic gases. These gases enter ` medical literature. Polyvinyl chloride, come white due to the action of chlo the upper respiratory tract and lungs' * er of all the synthetic plastic polymers, rine gas. All of the mice died in a pe freely when inhaled. Damage to the has been implicated as causing one of riod of 15 minutes after exposure to. lungs may result from exposure to a ' }): the most insidious, serious problems PVC fumes. Electrocardiographic ab group of gases and vapors called pul-' ' in fire fighting today, due to its re normalities appeared prior to gener monary irritants (chlorine, phosgene, lease of HCI gas while burning. Mists ation of large quantities of smoke. nitrogen dioxide, sulfur dioxide, and Hi of hydrochloric acid are considered This indicated that a harmful gas ammonia). On entering the lungs, less harmful than anhydrous HCI be . produced at an early stage was caus- these agents react chemically with . <;fii cause the droplets have no hydrating ing the effect. Similar results were water to produce strong acids or al action. 1 *, Animal Experiments . found on exposure to polyurethane gas. Kishitani conduded that the in jurious properties of burning mate kalis. A violent inflammatory re sponse occurs, causing destruction of lung tissue. ' ^ Cl \ ... The toxicity of PVC has been sub-, rials such as wood, fire retardant ply Fire fighters and victims of fires in stantiated by Kishitani* in his com wood, melamine finishing board, and homes, offices, and industrial com Vi- prehensive animal experiments, per- acrylic resin are due to CO. plexes are exposed to smoldering and f 394 . JAMA Jan 26, 1976--Vol 235. No 4. Polyvinyl Chloride--Dyer & Esch ucc 008731 plastia'nrf synthetics from ie, concrete that ret:.ins a great 'f,furniture, floor nnri wallcoverings, amount of heat and . leases fumes if Julies, end building materials. throughout the overhaul phase. Our iUfnv plastics produce large volumes testing has shown highly toxic con 'SwF'piilnionary-irritant gases when centrations of HCI in this concrete for Poli-vinvl chloride is used ex as long as one hour after the fire has pensively in' furniture, both in the . been extinguished. sighed plastic stuffing as well as the itring-> Burning 450 gm of this ma- FUEL LOADING ial produces 320 gm of chlorine, In the late 1960s, the type of "fuel tj^egdne, and HC1, all of which are loading" in office and high-rise build jtn>ng pulmonary irritants. In all, ings (ie, contents of the buildings) i^tere are 75 known products of PVC changed significantly and initiated a feipgradation. Practically every struc- new awareness. The noncombustible I'.ttu* today contains plastics capable buildings were not burning, but fur ^W.'producing lung-damaging gases niture within them, building insula ;'Vnftn .burned. Therefore, the fire tion, ceiling tile, wall paneling, and :yjjhterfacea a great, new risk in al- decorations made partly or wholly of ^jawat any fire. plastic were fueling disasters. ^rtb became obvious that a particular While a building may be con ^pattern was emerging in which cer- structed of fire-resistant elements, ' .taiii fire situations were productive of there is no control over the combus . insidious and unpredictable fire casu- tible material that an individual may .: allies. The letbal chemical smoke was elect to bring into the structure. This determined to be HC1 resulting from is the "fuel load" and may be ex ;,; tbe - decomposition of PV,C plastic pressed as kilograms of combustible v'ned in telephone cable and electrical material per square meter of floor 1 V;equipment installations. area. Large differences exist in com 3 We have found electrical and tele- bustibility, smoke, and toxic gas re phone cable fires to be especially haz- lease among different 'combustible ; . doUs to the fire fighters, due to the materials More than 50 sq m of red toxic gases produced. We have found oak, all burning at its maximum rate, f1 that when a short circuit developed in would be required to produce the a main switch, usually located in a same rate of smoke as 2.5 meters of ' mb-basement or penthouse of an of- acrylonitrile-butadienc-styrene plas See building or apartment house, the tic pipe. A fire of plastic materials de .area was always poorly ventilated, velops extremely high temperatures and the plastic-covered switches because plastics possess a heat of - quickly heat to temperatures in ex- combustion 2ti times that of other -,'cess of 93.3 C.'The heated conductors - combustibles. Therefore, the fire . cause the plastic insulation to decom- would magnify the normal problems .'"pose and emit white, mist-like HC1 of radiant heat, structural damage, `. ".ftunes that resemble steam. When the ' and exposure. The fire would exhibit a ^temperature range of 232 to-321 C is very high burning rate because the : .attained, the gas may be invisible. flammability of plastics is much i^The fire fighter may be fatally de-, higher than that of other combus -':ived if he does not know plaatic-cov*. tibles. ,\ertd cable is involved in the fire he is' The four most common plastics pro-. ^fighting. ' > i1! duced in the United States in the past OVERHAUL PHASE few years are polystyrene, polyethyi ene, polypropylene, and PVC, A chlor- " .The, period of time just after the ethylene polymer is a plastic solid fire is extinguished is termed the marketed under a variety of trade "overhaul phase." This is when the names, and currently being manufac fire fighters clean up the foreground. tured at a rate over 8.3 billion kilo & .Toxic smoke and emitted. This is fumes are a serious still being time for , grams annually. Polyvinyl chloride (Fig 2) is a plas ' toxic gas inhalation to occur since tic solid widely used as a rubber sub many fire contained fighters remove their breathing apparatus selfdur stitute and as electric and telephone wire and cable covering. It is also uti ing this phase. Another special hazard lized frequently in electrical fixtures, during this phase is the "heat sink," plastic drains, as well as waste pipe JAMA,.Jan 26, 1976-Vol 235. No 4 . "' v-*1.; -, 1 .; , -1 - -."-w. ,.r\ v ;,j ^ --CH, CH -vCH2 CH____ _ If.-' >.*.1 ci Fig 2--Polyvinyl chloride. " for interior plumbing, pliable thin. '| sheeting, film finishes for textiles, "noninflammable" upholstery, rain- coats,' tubing, belting, gaskets, shoe - soles, disposable uhbreakable plastic ; bottles, packaging materials, auto- mobile and aircraft seatcovers, cor- , rugated fence toppings, tarpaulins, y shower curtains, phonograph records, plastic trays, baby pants, toys, cur tains, and office copying-machines. It is used as an exterior finish in many ' ' vehicles, including buses and subway cars, because of its high resistance to ; f. wear and soiling. ., When PVC is heated to 225 C, noth ing happens. When heated above * that, up to 475 C, PVC does not burn. 1 The combustion range or flame point . is 475 C. Between 225 C and 476 C, PVC loses over 60% of its weight. 1 During this process, it thermally de- - grades and HCI is released. Four hun- dred fifty-three grams of PVC at deg1 radation releases 320 gm of chlorine, phosgene, and HCI. The individual toxicity factors of phosgene and the other major decom position products of PVC, ie, benzene, toluene, total xylenes, naphthalene, and vinyl chloride, are very small, compared with the toxicity factor of HCI. Further, the total or additive toxicity factors of these minor compo nents are also very small in compari son with HCI toxicity. Unfortunately, very little is known about the syner gistic effects of toxic gases (ie, the ability of one chemical to increase or decrease the toxicity of another). The main toxic risks from the decomposi tion products of PVC are HCI and CO.1 Stone et al* elucidated the nature of smoke aerosol and its role in the . transport of toxic gases in fire situ ations. They confirmed the fact that the toxic gas, HCI, is adsorbed on soot aerosol. Possible inhalation hazards of . such soot are positively related to the size of the soot particles and particle agglomerates. It'has been shown that - .. wa Polyvinyl Chloride--Dyer & Each' 195. , / ucc 008732 A, i ilium nn. the amount and location of particle elapses Itetw'-cn exposure and onset bient to fiOO C. Exposure to this airy^.^ deposition in the respiratory tract de- of severe re; piratory and chest symp stream supplemented with o---x--y--g--e--n.a^*,:/- Vends on the particle size.' On inhala toms. Treatment is most effective if produced pulmonary und interstiti*^,i . tion, soot aerosols would enter the given during this quiescent phase. edema in rats. Some of these animala.'v'rj j;, lower lung region and, to an extent, Once the symptoms of difficult also showed focal bronchial and intra^yvij `v,' be retained there. Soot particle clus breathing, cyanosis, or other symp alveolar hemorrhage. v ters,,with sizes ranging from O.l/t to " toms, as noted in the reported case, In a sealed environment (such as*1?-* % 2.5ft in diameter, would be retained in have appeared, it may be too late to centrally air-conditioned house, the alveolar sacs to an extent of from prevent severe morbidity or even lice, high-rise unit, or hospital), fumes vjl V, 20% to 40% of those particles inhaled.' mortality. The "overhaul phase" after from plastic degradation could kill/,*/.'' At a breathing rate of 18 litera/min the fire is extinguished is dangerous even if the fire is brought under con for an exposure of one hour, a max with respect to fumes also. trol. It has been observed that :> imum of 0.7 gm of soot bearing 13 mg' , A Harvard research team headed ;' sleeping person needs an estimated,v:, of loosely bound HC1 would be. re by Donald P. Dressier, MD, reported 12 to 15 minutes to awaken, react tow^ '>' tained in the lower lungs. in 1973 that when burned, plastics and danger, and take appropriate action-. . The effect of HC! in the gas phase . modern fibers produced colorless, to save himself. With inhalation of$TC is largely limited to irritability, odorless fumes that quickly displace fumes from burning plastic, ' a will. 7. mainly affecting the upper respira oxygen and cause a dramatic rise in ; not have that much time. f tory tract, whereas loosely bound HC1 the CO, level of the atmosphere.' COHb LEVEL AND CIRCULATION 1$ -V : condensed on soot aerosol gains ac- Therefore, a person either dies or is *Vtf !;* ' cess to the lower lungs. Experiments rendered unconscious in the early - As noted by E.P. Radford (writ-<i*` have shown that water droplets of stages of a fire involving these mate ten communication), 43 deaths due to.':;./ respirable size rapidly adsorb HC1 rials. If he is unconscious, he soon dies fire demonstrated that a blood COHb.V, ' from the gas phase and approach of other lethal fume inhalations.1 level of over 65% is nearly always'1*, ^ rf equilibrium concentrations in frac Tests performed in Cambridge, Mass, ' lethal due to the depression of res-i ^ 7. ' tions of a second.'- showed that fire fighters were proba- - 1 piration and circulation. Ventricular, ,-^i SMOKE INHALATION .bly affected adversely by the high' fibrillation from acute myocardial hy-7|:,.J }' level of CO, rather than by the initial ', poxia induced by a rapid rise of j; / Respiratory distress may develop _ release of toxic gases.* COHb level in individuals with a , in fire fighters or fire victims immedi- In establishing the importance of -restricted coronary. circulation was './!} ately or within one to two days of ex- . detecting the presence of certain - found to be the likely explanation of ;/. r` , posure to combustion products. The toxic gases, the difficulty in detecting - a lower terminal blood COHb level ,-,11 j best protection against these agents CO has been emphasized.* Some hu*' , These individuals were found to have is the mandatory use of the self-con man response mechanisms are more - severe, preexisting coronary vascular] tained breathing apparatua by every sensitive than others to CO inhala-. ' disease. 1" fire fighter. When anyone without a tion.' Fairly high levels of CO affect a We believe thst any compromise of. v/: breathing apparatus is exposed to human's vision, but even higher levels : the coronary circulation, eg, ath more than a few breaths of "choking do not affect his sense of timing. A re erosclerosis such as found in the fatal smoke" characteristic of burning or search team beaded by R. A. McFar case, would be potentiated by highly smoldering plastics, he should receive . land, MD, of Harvard University, : irritating chemical fumes. We also fry*. prompt medical attention. found that when CO replace* 11% to - believe that other pyrolysis products,' ;* y Prior to our investigation, we con 17% of the blood's normal oxygen, the ' especially HCI, have contributed to-^ ji sidered most foreground pulmonary ' peripheral- vision is affected and the - ' ventricular fibrillation since its con-': y/.i casualties to be due to "smoke inhala subject has difficulty viewing stimuli . centration is comparable to that of cK tion" or CO poisoning. Carbon mon at a 20* angle from the line of sight.' . CO in real fire situations involving* ,-j V oxide had long been considered the The Harvard team also found that at: plastics. i'y leading cause of death and pulmonary a 17% concentration of COHb, some' Kisbitani has demonstrated that-'/; morbidity in fires. Though CO is not subjects hsd s momentary lapse of at-' . chlorine affects the myocardium more.>; noxious and does not actually cause ' tention and failed to respond to all rapidly and more severely than CO. ; ' serious pulmonary injury, the amount ' the stimuli presented. This is impor- v: Carbon monoxide may cause changes-"V- / of CO in a patient is a good indicator tant in disproving the once-held con- ' in enzyme activities suggestive of /, of whether more harmful gases are . cept that once an individual has de- myocardial damage. Hydrogen chlo- present. . tected the sharp odor of HC1 he can ride has been found to he a more po- ./lj Before the introduction of massive - . walk away. It has been our observa-, tent myocardial irritant whose ef-i;"l fire loads of combustible and ther tion that the fire fighter cannot es-'' fects may be difficult to determine by 'if1/ mally decomposable plastic products, cape the HC1 fumes. . / dinical observation. This is in con-, fire surgeons usually considered the Cornish and Abar reported that CO . junction with the development of pul- -,f. ^ CO victim to be "home safe" in four and hydrochloric acid were the major monary edema over a 24-hour period- hours after exposure due to the fast toxic products from the combustion of 1 following exposure to HCI. This (ur-//5 half-life of CO in the blood. After ex-' PVC." They pyrolized PVC polymers . ther complicates and compromises posure to plastic degradation prod- - in a stream of air by gradually in- coronary artery oxygen saturation..-; ucts, a period of . one to six hours , creasing the' temperature from am -This could lead to sudden death syn- >M JAMA Jan 26, 1B76-VOI 235, No 4 ',i; Polyvinyl Chlorlo#--Dyer 4 Esch /bW.; - .j/ `SI. * * t ` ucc 008733 "r <Jroroe, similar to that in the reported last 26 firemen exposed had prema . `< c>#c Although in the cases of CO poi- ture ventricular contractions. Some j . N^ning noted hy G. Cordon, (written have had recurronii: of cxtrasystolcs " viaunmunicatton) the ECC changes did within the subsequent year. Chest x- appear late if at all and the COHh ray films were done at the initial varied in individuals at the same fire examination and have remained nor i-'tVai'well as in different fire situations, mal. Serum electrolyte and arterial ^'^it has been our experience that all blood gaa determinations were per Ifighters exposed to PVC do mani- formed on 12 of the fire fighters who i.'v si;* ^ qq signs of its toxicity. There. . were more acutely ill, or required hos- <-r '''uv variable levels of its toxic effect - pitalization. Because of the excellent ,y-! ^ the lungs, mucous membranes (tra- clinic facilities provided by the Dis 'foj '^beal peeling effect), eyes, and other trict of Columbia government, all fire Yif'parts. of. the body. fighters were observed in a holding CLINICAL STUDY area after exposure and examined at ; the clinic or the hospital emergency ' In Washington, DC, a clinical study room after transportation from the i / ;,of fire fighters suspected and later, fireground. Twelve men were ad '.i'Kknown to have been exposed to toxic . mitted to the hospital for treatment. V, '"^ products from thermal degradation of If symptoms did not worsen over the ' fV.' PVC waa conducted by the DC Board ' ' first 24 hours in the hospital, they of Police and Fire Surgeons between ' were released and followed up on an .';i;'J*nuary 1970 and September 1975.- outpatient basia at the clinic. ;i;VOne hundred seventy individuals Specific treatment, including oxy C^'.were exposed from one to four differ- gen given intranasally at 5 liters/ '^ent times to these products and re- min, bronchodilators, antihistamines, -j,;' ported two or all of the symptoms of . and decongestants in oral suspension, 1 ` scute toxicity, ie, pain in the anterior has been utilized in controlling most i /' aspect Of the chest, neck and throat of the acute respiratory symptoms. : t j;'- ,, pain, dyspnea, severe headache, dizzi- Steroids were given intravenously to ; ness, and irregular pulse within a few " . three of the fire fighters during hospi 'j"J.hours after exposure. talization due to the severity of their Initial physical examinations were ' signs and symptoms of respiratory performed by the fire surgeon on the diatress. !> flreground, in the hospital emergency Initial and follow-up liver function . , ii^l'room, or at the Police and Firemens tests have remained normal in all of 7 Clinic. Laboratory studies including these patients. There has been no di "j-;: /complete blood cell count, determina- rect correlation between severity of i^.ftions of serum glutamic oxaloacetic ' symptoms .and history of cigarette *}/ transaminase, blood urea nitrogen, or smoking. 'i.Vjjcreatinine, and a complete urinalysis None of the fire fighters has had were done. Electrocardiograms were to retire for permanent airway dis .performed initially when there was orders. Serial studies and follow-up jf'Vdiest pain, extrasystoles, or cardiac examinations will continue. Since the '*1 ^arrhythmia. UHoawwaevvaepr, ECG sstttuirdiiiaees onset of this study among profes- <> ; were not incorporated as part of the 1 sional fire fighters, the use of the self- i;1-; physical evaluation until the latter contained breathing apparatus has part of the study when their impor- been required at all fires where toxic "."tanee was appreciated, fumes could be present. This is neces j'f-'; 'About one fifth of the fire fighters sary during' the "overhaul phase" V had extrasystoles during the first few also. We urge all physicians to advo ' 'v hours after exposure. Fourteen of the cate restriction of unsuperviaed use , Relerencea * l* Lowery R: Injury Control at Heavy Service 4\Oeetmoal Fine, safety bulletin. City of Now York Fire Dept, September 1969. 2. L* T: Smoke Analytic of SfKciment Sub* . .' by Fxre Marshal Clark of /Vince George* \ CwtTL/y, Maryland, US Dept of Commerce, Sept ;25, 1969. 1 " 3. Six N!1 Dangerous Properties of Industrial ->Y .j *d 3 New Yorlt, D Van Noetraod Co 1968, p 883. /J > ,4. Kiihitini K; Study on injurious propertita t ,t i j> ] : /JAMA, Jan 26. 1976-Vot 235. No 4 - ' i* of corobustive product! of building materials at the initial stage of fin- J Faculty Engineering University Tokyo (B) 31:1-35 (No. 1) 1971. 5. Woolley WD: Decomposition products of PVC for studios of fires. Br Polymer J 3186-193, . 1971. 6. Stone JP, Hulett RN, Johnson JE, ft si: The transport of hydrogen chloride by soot from burning polyvinyl chloride. J F\re Flammability 4:42-51, 1973. 1 7. Stone JP: Transport of hydrogen chloride of PVC products. Fire research activ- | ity should be maintained at a na tional level to continue study as well ` as preventive measures for HC1 tox icity in PVC fires. CONCLUSIONS 4Hazards of Plastic Fires.--Respira- /, . lory distress may develop in fire . fighters and fire victims after expo-. , sure to combustion products. The complexity of the problem is empha-.1 sized when it is recognized that the ' thermal degradation of PVC results in the formation of at least 75 identi-1 liable potentially toxic compounds. Three characteristics of plastic fires are the extremely high temperatures,. very high burning rates, and thick.' toxic smoke. The main danger to ex- ! posed fire fighting personnel at the v fireground results from the massive " formation of HCI gas, and in many / instances, its adsorption on spherical soot particles that are carried into the victims' respiratory tracts. Prevention.-The mandatory use of the self-contained breathing appa ratus by all who will be vulnerable to 1toxic smoke will aid in the prevention of plastic fires. Control .of hazardous ; .' ! building designs, including equip ment and ventilation is also neces sary. Protection by masks during the "overhaul phase" should be required. Sophisticated air-sampling tech niques are required for definitive study, including gas chromatography. Electrocardiographic studies utilizing base line tracings directly after HCI exposure are stressed. Areas of Future Study.-All atmo spheres should be suspected by the . fire fighter. There should be a search for an effective gas analyzer that can immediately assesa gas concentra tions released by burning or smolder ing plastics. Further definitive car diologic studies are indicated. The term "smoke inhalation" should be abandoned and replaced by "inhala tion of toxic combustion products." by water aerueol in simulated An. J Fire Flammability &127-13A, 1975. 8, Fibers, plastic fumes caum smoke deatha, editorial. Int Fire Fighter 56:8. 1973. 9, Medical tribune report Human rteponae mechanism may vary in carbon monoxide sensi tivity. Med TViiurt/ Nov 8, 1972, pp 1M6. 10, Cornish H. Abar E: Toxidty of pyrolysis products or vinyl pUstia. Arek Environ Health 19:16-21, 1969. Polyvinyl Chloride--Dyer & E&ch IJCC 008734