TY - JOUR
AU - MD, Emin Kapi,
AB - Abstract Liquefied petroleum gas (LPG), which is used as a type of fuel, is stored as a liquid under high pressure in tanks. Immediate and sudden explosion of these tanks can release a large amount of gas and energy into the environment and can result in serious burns. In this study, the cases of 18 patients injured due to LPG burns in five incidents were examined, along with their epidemiologic features. The authors also investigated the causes of the LPG tank explosions. Inhalation injury was present in 11 cases with varying degrees of severity, and 7 patients subsequently required mechanical ventilation. The explosions resulted from weakening of the tank wall (n = 2), crash impact (n = 2), and gas leakage from the tank (n = 1). LPG-powered cars are becoming more popular because of their lower operational costs. However, LPG tanks can be hazardous in the event of a tank explosion. Burns caused by explosions of the LPG tanks in cars have significant mortality and morbidity. This danger must be taken into account and public awareness must be increased. Liquefied petroleum gas (LPG) is a fuel that has been widely used for domestic, agricultural, and industrial purposes. It is a mixture of commercial butane and propane gases (60:40) and is obtained from crude oil in petroleum-processing plants. It is liquefied by pressurizing and cooling as its boiling point is less than 0°C (−2°C for butane and −45°C for propane at atmospheric pressure). The boiling point of LPG lies between the boiling points of butane and propane with the actual temperature depending on the mixture ratio. Pressure reduces the boiling point of LPG.1 The air pressure at sea level is 1 bar (1.03 kg/cm2). In Turkey, LPG tanks are filled to a pressure of 3 to 5 bars (43–73 pounds per square inch). When the pressure exceeds 27 bars, safety valves open and reduce the tank pressure. LPG-powered cars (Figure 1) are becoming more popular because they present many advantages. In the United Kingdom, for example, LPG is promoted by the government as being environmental cleaner because it burns easily and completely. Moreover, LPG is cheaper than petrol.2,3 Figure 1. View largeDownload slide The appearance of an LPG tank in the trunk of an automobile. Figure 1. View largeDownload slide The appearance of an LPG tank in the trunk of an automobile. However, if a tank containing LPG is damaged for any reason, the tank may release enormous quantities of evaporating gas and energy, which has a destructive effect on the tank and its surroundings. The degree of danger depends on many factors, including the mass of substance released, the rate of gas release, and the physical–chemical properties of the substance at the moment of its release.4 Sometimes, the outflow of LPG is relatively calm and does not present a direct hazard to the environment. However, more often than not, this occurrence can result in disaster. The most dangerous scenario is a boiling liquid expanding vapor explosion (BLEVE).5 A BLEVE occurs when there is an abrupt transition of a media from the liquid to the gas phase. This type of leak is caused when there is extensive damage, usually in multiple places, to a tank containing a pressurized liquid such as LPG. The tank may fail because of the action of an external fire source, overfilling of the tank, or weakening of the tank wall material caused either by corrosion or by mechanical damage as a result of an accident.6 When external heat or impact increases the internal pressure of the tank, the tank suddenly and violently ruptures. It follows that the tank's contents, once released, will ignite. Therefore, a BLEVE results in a large fire or fireball, which consist of smoke, obscured flames, and luminous band (extremely bright light). Thermal radiation is emitted from the fireball's luminous band. The spreading effect of thermal radiation is intense and has the potential to cause severe health damage and even loss of life. The effect on human health of the exposure to thermal radiation depends not only on the intensity of the radiation, but also on the duration of the exposure.4 In this study, we examine burn injuries caused by the explosion of automotive LPG tanks. Moreover, we investigate the explosion of LPG tanks from these vehicles and discuss preventive measures that can be taken to avoid such explosions. MATERIALS AND METHODS Between March 2001 and May 2006, 18 patients were treated at the Diyarbakır Military Hospital and Dicle University Burn Unit for burn injuries related to LPG-powered cars. These 18 patients were injured in a total of 5 separate incidents. The demographic features of the patients, characteristics of the burn injuries, and mechanisms underlying the tank explosions were investigated. The resuscitation formulas used in the study were the modified Parkland formula (lactated Ringer's + 50 mEq NaHCO3) for adults and the Galveston formula for children. As a colloid replacement, we used fresh frozen plasma in adults and albumin in children; we tried to maintain the serum albumin above 2.5 g/100 ml after the first 8 hours. Fluid resuscitation was monitored using clinical parameters such as urine output. Urine output was maintained at 30 to 50 ml/hr in adults and 1 ml/kg/hr in children.7 Prospectively, diagnosis of inhalation injury was suspected in patients with facial burns and confirmed with fiber optic bronchoscopy and chest radiographs. Daily dressing changes and wound care were performed. Wound and blood cultures were obtained and specific antibiotics were administered according to the antibiograms. Early serial excision of the wounds was only performed when the family or patient consented. Autografts and homografts were used for wound coverage. RESULTS Of the 18 patients, 9 were children (mean age: 6.7 years) and 9 were adults (mean age: 34.1 years old). Eleven of the victims were female and seven were male. The mean total burn surface area for these patients was 31.1% (range: 13–57%). The mean hospital stay was 42 days (range: 12–64 days). The follow-up period varied from 9 to 38 months (mean: 21.1 months). The demographic features of the patients and the treatment procedures applied are shown in Table 1. Table 1. The demographic features of the patients documented here and their corresponding treatment procedures View Large Table 1. The demographic features of the patients documented here and their corresponding treatment procedures View Large The causes of the explosions were weakening of the tank wall (n = 2), crash resulting in impact to the tank (n = 2), and leakage from the tank (n = 1). We found no correlation between the severity of the explosion and the severity of the burn injury. Because the explosions occurred when the victims were in a car, the burn injuries occurred in an enclosed area, which increased the inhalation injury rate. Inhalation injury was present in 11 cases with varying degrees of severity; 7 of these patients subsequently required mechanical ventilation. Three patients who required mechanical ventilation died because of acute respiratory distress syndrome (16.7%). In three cases, early serial excision could not be performed because the general status of these patients was poor and the patients or their parents did not agree to the operation. Debridement and grafting were performed in 12 patients. The wounds of two patients underwent healing by spontaneous epithelization. DISCUSSION Because of its significantly lower cost than gasoline, the use of LPG as an energy source in cars has increased in many countries, including the United Kingdom, Canada, Holland, Japan, Korea, and Australia.8,9 LPG is especially preferred in commercial automobiles like taxis. In Japan, the rate of LPG usage in taxies is 94%.8 An increase in LPG use has been observed in other countries too. In recent years, however, questions have arisen about the safety of LPG.10 Certainly, the environmental damage resulting from LPG explosions and the resulting thermal radiation should be taken into consideration.9 Victims of this exposure experience significant morbidity and mortality related to burn and inhalation injury. In the literature, however, there are no data available regarding possible burn injury risk and clinical case series with LPG-powered cars that have standard manufactured tanks and good quality LPG. According to safety standards in our country, an LPG tank's wall must be made of sheet iron that is about 3 to 4 mm thick and the tank must be durable against 67.5 bars of pressure. If the tank is manufactured according to these standard, it is extremely resistant to any crushing and weakening.11 However, overfilling the tank beyond 80% of its total capacity must not be attempted. Furthermore, the copper tube connecting the tank to the automobile, through which LPG flows, must be durable against 45 bars of pressure. Also, it has been recommended that connection tubes be changed every 4 years as a preventive measure to reduce any possible corrosion effects. The prescribed lifetime of the tank is 10 years; the tank must not be used longer than that. As such, the tank must be labeled with the expiration date.11 However, all of the injuries in this series resulted from substandard tank manufacturing. As the studied region is quite near to northern Iraq, there may also be a possibility of contraband LPG usage, which is associated with substandard quality. LPG forms a flammable mixture when combined with air. The flammable range of vapour concentrations in air at ambient temperature and pressure is approximately 2 to 10%. Within this range, there is an ignition risk. Outside this range, the mixture is either too weak or too rich to support a flame. However, overly rich mixtures can become hazardous when diluted with air; these will burn at the air interface. Escape of even small quantities of the liquefied gas can give rise to large volumes of a vapour or air mixture, and thus can cause a hazard. A container that has held LPG and is “empty” may still contain LPG in vapour form and thus be dangerous. If a valve is leaking or left open, air can diffuse into the container, forming a flammable mixture and creating a risk of explosion. Therefore, a design is problematic if it does not account for this scenario in LPG tank production. One explosion in these series was due to valve failure, which is directly attributable to substandard manufacturing. In less developed countries, people use substandard LPG tanks to reduce cost. In addition, there are no legal ramifications regarding the inappropriate production of LPG tanks.4,5,10 In addition, the mixture ratio of propane to butane varies from country to country. It is easier to convert propane to gas from liquid; as such, the proportion of propane is increased in countries with a cold climate. However, as the proportion of propane increases, so does the potential for an explosion. This makes preventive measures even more important when the propane ratio in LPG increases.4 The mechanism underlying BLEVE of LPG tanks in cars must be well understood so that preventive measures can be taken. In our study, one of the causes of tank explosion was the weakening of the tank wall. As the LPG tank wall thickness decreases, the effect of environmental temperature increases. Thus, to prevent possible explosions, several safety measures should be enacted. First, the car tanks should be inspected at least once a year. This would not markedly increase the cost of having a LPG-fueled car in our country because the inspection fee is quite low; however, this requirement might significantly increase costs in some countries. In addition, the factories that produce LPG tanks should provide an inspection service at no extra cost to make service more attractive for drivers. The factories that produce LPG tanks must also be quality controlled; only certified factories should be permitted to produce these tanks. Because overfilling is associated with increased risk, overfilling of tanks must be avoided as well.4 Furthermore, small-volume tanks generate less damage than larger tanks and pose a reduced potential risk.10 In Turkey, there are no current laws against or punishments for people who perform substandard and illegal conversion of gasoline-powered to LPG-powered automobiles. The government should immediately take action to enact effective laws against and punishments for this activity. Smoking in a car that is powered with LPG can cause an explosion in the event of a LPG leak. The drivers of LPG-powered cars must be aware of this danger. One incident in this series was caused by tank leakage being ignited by driver smoking. Entrance of LPG-powered automobiles into enclosed autoparks has been banned in Turkey. To make a distinction between gasoline and LPG-powered cars, stickers indicating LPG-powered cars should be placed on the windshield and rear window of these cars. This regulation is highly beneficial in terms of protecting the enclosed area from gas accumulation. In many enclosed autoparks, air conditioning systems have been placed on ceilings and walls. Because propane spreads and remains close to the floor, the current air conditioning systems are ineffective in clearing this gas. For this reason, construction of floor-height air conditioning systems and the use of high-powered air conditioning equipment are recommended, given the increased usage of automobiles that run on propane.12 When the demographic features of the victims in this study were evaluated, the types of burns that occurred appeared to be similar across all individuals, regardless of age and sex. According to our observation, the size of the burns was considered to be large compared with other types of burn injuries. Another important feature of this injury is that most of the patients had inhalation injuries, which increase mortality and morbidity. In the two pediatric patients who died, the lack of excision that lead to increased levels of inflammatory mediators and increased infection risk have contributed to the deaths. Status of these patients progressively deteriorated and multiorgan failure were developed. In addition to severity of the inhalation injury that ventilation in the operation suite would be impossible, surgeons were not allowed to operated (their family rejected the operations because of cultural and religious related reasons). Smoke inhalation exposure injuries, which are especially common with burns occurring in an enclosed environment, require mechanical ventilation support and can result in respiratory problems and even death. In the 11 cases of inhalation injuries in our study, different levels of injury were observed. This frequency of injury, however, shows that smoke inhalation is nearly unavoidable. Another important point to note is that anesthetic toxicity through accumulation of isobutane in the context of LPG exposure may create a narcotic effect leading to fatal arrhythmia.13,14 Butane can accumulate in the blood, heart, stomach, kidney, and fatty tissues.13 Preoperative evaluation of these patients by an anesthetist is imperative. Anesthesiology and reanimation department of our institution prefers Sevofluran (Sevorane, Abbott, Turkey) and Desfluran (Suprane, Eczacibasi-Baxter, Turkey) as appropriate anesthetic agents for these patients. In conclusion, cars running on LPG are not rare because of the economic status of our country. However, the conversion of gasoline-powered to LPG-powered automobiles is a delicate procedure that must be performed by highly skilled professionals. As this type of car is preferred by members of lower socioeconomic groups, these persons often do not know the potential risks and fail to perform periodic examinations of their cars. Mass media should caution consumers regarding the potential dangers of LPG usage. Burns caused by LPG tanks in cars have significant mortality and morbidity, and public awareness must be increased accordingly. In addition, effective legal mandates regarding the inappropriate production of LPG tanks must be enacted to act as a deterrent against this practice. REFERENCES 1. Murugkar PM, Jones NW, Shokrollahi K, et al.   Hand burns sustained whilst refuelling car with LPG (liquefied petroleum gas). Burns  2006; 32: 515– 16. Google Scholar CrossRef Search ADS PubMed  2. LP Gas Association. http://www.lpga.co.uk. Accessed October 29, 2007. 3. http://www.est-powershift.org.uk. Accessed October 29, 2007. 4. Stawczyk J Experimental evaluation of LPG tank explosion hazards. J Hazard Mater  2003; 96: 189– 200. Google Scholar CrossRef Search ADS PubMed  5. Birk AM, Cunningham MH. A medium scale experimental study of the boiling liquid expanding vapour explosion (BLEVE). TDC Report. TP 11995E. 1994. 6. Wiekema BJ Vapour cloud explosions—an analysis based on accidents. J Hazard Mater  1984; 8: 295– 329. Google Scholar CrossRef Search ADS   7. Warden GD Fluid resuscitation and early management. Herndon DN Total burn care.  London: Saunders; 1996 53– 60. 8. Ristovski ZD, Jayaratne ER, Morawska L, et al.   Particle and carbon dioxide emissions from passenger vehicles operating on unleaded petrol and LPG fuel. Sci Total Environ  2005; 345: 93– 8. Google Scholar CrossRef Search ADS PubMed  9. Son B, Yang W, Breysse P, et al.   Estimation of occupational and nonoccupational nitrogen dioxide exposure for Korean taxi drivers using a microenvironmental model. Environ Res  2004; 94: 291– 6. Google Scholar CrossRef Search ADS PubMed  10. Raj PK Exposure of a liquefied gas container to an external fire. J Hazard Mater  2005; 122: 37– 49. Google Scholar CrossRef Search ADS PubMed  11. Otogaz Turkiye. http://www.otogaz-turkiye.com/acik-alan/lpg-kulanicilarin-bilmesi-gerekenler.html. Accessed March 13, 2008. 12. Castenfors K, Svedin L Crisis communication: learning from the 1998 LPG near miss in Stockholm. J Hazard Mater  2001; 88: 235– 54. Google Scholar CrossRef Search ADS PubMed  13. Gallagher F, Mason HJ Carbon monoxide poisoning in two workers using an LPG forklift truck within a coldstore. Occup Med  2004; 54: 483– 8. Google Scholar CrossRef Search ADS   14. Sugie H, Sasaki C, Hashimoto C, et al.   Three cases of sudden death due to butane or propane gas inhalation: analysis of tissues for gas components. Forensic Sci Int  2004; 143: 211– 14. Google Scholar CrossRef Search ADS PubMed  Copyright © 2008 by the American Burn Association
TI - Burn Injuries Related to Liquefied Petroleum Gas-Powered Cars
JF - Journal of Burn Care & Research
DO - 10.1097/BCR.0b013e31818b9e29
DA - 2008-11-01
UR - https://www.deepdyve.com/lp/oxford-university-press/burn-injuries-related-to-liquefied-petroleum-gas-powered-cars-hl0zFj2Drs
SP - 897
EP - 901
VL - 29
IS - 6
DP - DeepDyve
ER -