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CBRNE - Incendiary Agents, Napalm

Author: Lisandro Irizarry, MD, MPH, FAAEM, Chair, Department of Emergency Medicine, Brooklyn Hospital Center; Assistant Professor, Department of Emergency Medicine, Weill Cornell School of Medicine
Coauthor(s): Mollie V Williams, MD, Assistant Clinical Professor, Fellow in Disaster Preparedness, Department of Emergency Medicine, State University of New York Downstate Medical Center, Brooklyn; José Eric Díaz-Alcalá, MD, FAAEM,, Consulting Staff in Medicine Service, Division of Emergency Medicine/Medical Toxicology, Veterans Affairs Caribbean Healthcare System; Medical Director, Puerto Rico Poison Control Center, San Juan, Puerto Rico
Contributor Information and Disclosures

Updated: May 8, 2009

Introduction

Background

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 resulted in the enhanced 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 2 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.

Frequency

United States

Napalm has been used by the United States as recent as the Persian Gulf War.

Mortality/Morbidity

Morbidity and mortality are related directly to the extent of injuries received from trauma and extensive burns from exposure. 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.¹

Clinical

History

• Exposure history usually is obvious, with the individual recounting the sounds of an explosion and the unbearable pain associated with the burns of exposure.
• Napalm produces carbon monoxide as a by-product of combustion. Thus, also evaluate individuals exposed to burning napalm for carbon monoxide exposure. In particular, consider individuals who are found with altered levels of consciousness near burning napalm to have been exposed to toxic levels of carbon monoxide until proven otherwise.

Physical

• Immolation, asphyxiation, and burns are the mechanisms by which incendiary weapons kill or wound.
• Immolation results in a rapid decrease in blood pressure leading to unconsciousness and death.
• Asphyxiation usually occurs as a result of napalm ignition, which results in a rapid deoxygenation of surrounding air. This rapid deoxygenation results in an atmosphere of approximately 20% carbon dioxide.
• Severe burns (second and/or third degree) are frequently found in areas exposed to burning napalm. Injuries related to the thermal elevation of the air temperature may result in respiratory embarrassment.
• Burning napalm raises the ambient environmental temperature and has been known to cause the deaths of individuals in raid shelters as a result of radiant heat and dehydration. This was a frequent cause of death in the bombing raids carried out over Hamburg, Germany, during World War II. The result of this phenomenon frequently was referred to as Bombenbrandschrumpfleichen (incendiary-bomb–shrunken bodies).

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