- Author: Lisandro Irizarry, MD, MPH, FACEP; Chief Editor: Zygmunt F Dembek, PhD, MPH, MS, LHD more...
Napalm, invented by Fieser in 1942, is an incendiary substance made by the simple procedure of adding a "gelling" powder, composed of naphthalene and palmitate (hence "napalm"), to gasoline in varying concentrations to form a sticky, combustible substance.
This white, cloudy, jellylike substance has unique properties that render it an effective incendiary agent. Napalm is extremely stable, tolerating temperatures well above 150°F (effective in the tropics) and as low as -40°F (bomb shelters, cold weather environments). It is not shattered easily by explosives and can be stored for long periods without significant breakdown.
Gelation of this substance occurs in 3-20 minutes. Gel formation enhances its effectiveness by allowing for a controlled, contained, and prolonged burn.
Gelation also enhances its stability, with napalm requiring much higher temperatures to ignite than gasoline. There is no "off-sourcing" of hydrocarbon fumes associated with the nonignited compound. In fact, ignition requires the use of trinitrotoluene (TNT) to explode and ignite white phosphorus, the ignited temperature of which is high enough to result in the combustion of napalm.
Napalm has been used primarily in the form of incendiary bombs, firebombs, land mines, and flamethrowers. During World War II, firebombs, in the form of 165-gallon containers, were the primary method for the disbursement of napalm. One firebomb released from a low-flying airplane was capable of producing damage to a 2500-yd2 area. During the Korean War, the United States dropped approximately 250,000 pounds of napalm per day.
Napalm's increased viscosity enhanced the effectiveness of flamethrowers, which were frequently used in World War II. Because of gasoline's increased instability, volatility, and its rapid burning and self-consumption, its effectiveness was limited to within 30 yards. Napalm, through its unique properties, extended the effective range of flamethrowers to 150 yards.
After World War II, the United States conducted an intensive effort to enhance the properties and effectiveness of napalm as an incendiary agent. This effort resulted in the development of napalm B (super napalm, NP2), which substituted polystyrene and benzene for naphthalene and palmitate. The resulting substance continued to bear the name napalm, although it lacked the two components of its namesake. Conventional napalm burns for 15-30 seconds, whereas napalm B burns for up to 10 minutes.
Napalm B provided the United States with an incendiary substance with enhanced stability and controllability and, as such, became the weapon of choice during the Vietnam War. Such enhanced stability required an igniting agent such as white phosphorus, which burns at a higher temperature of 4532°F. White phosphorus replaced thermite, the ignitor previously used for traditional napalm.
The United Nations Convection on Certain Coventional Weapons (1980) banned the use of napalm against civilian populations. This eventaully led to the complete destruction of the US stockpile stored at the Fallbrook Naval Weapons Station by April 2001. Despite this, allegations of napalm use by the United States have been made as recently as the 2003 Gulf War. The United States denied those allegations, acknowledging the deployment of Mark 77 incendiary devices, whose functions are similar to those of napalm when used in combat but whose chemical composition differs from that of napalm.
Morbidity and mortality are related directly to the extent of injuries received from trauma and extensive burns from exposure, in addition to asphyxiation from carbon monoxide exposure and hypoxia. No cases have been reported of systemic poisoning of individuals in contact with nonignited napalm.
German post-war estimates reveal approximately 25,000 deaths and 30,000 wounded individuals during a 2-day attack on Dresden, Germany, with the use of 3.4 kilotons of incendiary, half of which was napalm. According to a memorandum released by the Ministry of Foreign Affairs of the People's Republic of Korea, after the Korean War more than 10,000 napalm bombs were released during a 20-day period, killing 12,000 individuals and wounding 2,500 others.
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