page_title: Napalm
section_title: Composition
hierarchical_section_title: Napalm / Composition
caption_attribution_description: Napalm bombs explode on Nightmare Range after being dropped from a Republic of Korea Air Force F-4E Phantom II aircraft during a live-fire exercise.
context_page_description: Napalm is the name for a number of flammable liquids that have been used in warfare. Often it is jellied gasoline. Napalm is actually the thickener in such liquids. When it is mixed with gasoline, the thickener makes a sticky incendiary gel. It was developed by the U.S. in World War II by a team of Harvard chemists. The team leader was Louis Fieser. The name napalm has comes from the ingredients that were first used to make it: coprecipitated aluminum salts of naphthenic and palmitic acids. These were added to the flammable substance to cause it to gel.
  One of the major problems of early incendiary fluids was that they splashed and drained too easily. The U.S. found that flamethrowers that use a gasoline gel are able to shoot farther and are more useful. Gasoline gel was difficult to manufacture because it used natural rubber, which was in high demand and expensive. Napalm provided a far cheaper alternative. It solved the problems involved with rubber-based incendiaries.
  Nowadays, napalm is mostly made of benzene and polystyrene, and is known as napalm-B.
  Napalm was used in flamethrowers and firebombs by the U.S. and Allied forces.
context_section_description: Napalm is usually a mixture of gasoline with suitable thickening agents. The earliest thickeners were soaps, aluminum, and magnesium palmitates and stearates. Depending on how much thickener is added, the resulting viscosity may range between syrupy liquid and thick rubbery gel. The content of long hydrocarbon chains makes the material highly hydrophobic (resistant to wetting with water), making it more difficult to extinguish. Thickened fuel also rebounds better from surfaces, making it more useful for operations in urban terrain.
  There are two types of napalm: oil-based with aluminium soap thickener, and oil-based with polymeric thickener ("napalm-B").
  The United States military uses three kinds of thickeners: M1, M2, and M4.
  The M1 Thickener (Mil-t-589a), chemically a mixture of 25% wt. aluminum naphthenate, 25% aluminum oleate, and 50% aluminum laurate, (or, according to other sources, aluminium stearate soap) is a highly hygroscopic coarse tan-colored powder. As the water content impairs the quality of napalm, thickener from partially used open containers should not be used later. It is not maintained in the US Army inventory any more as it was replaced with M4.
  The M2 Thickener (Mil-t-0903025b) is a whitish powder similar to M1, with added devolatilized silica and anti-caking agent.
  The M4 flame fuel thickening compound (Mil-t-50009a), hydroxyl aluminum bis(2-ethylhexanoate) with anti-caking agent, is a fine white powder. It is less hygroscopic than M1 and opened containers can be resealed and used within one day. About half the amount of M4 is needed for the same effect as of M1.
  A later variant, napalm-B, also called "super napalm", is a mixture of low-octane gasoline with benzene and polystyrene. It was used in the Vietnam War. Unlike conventional napalm, which burns for only 15–30 seconds, napalm B burns for up to 10 minutes with fewer fireballs. It also sticks better to surfaces, and offers improved destruction effects. It is not as easy to ignite. This reduces the number of accidents caused by soldiers smoking. When it burns, it develops a characteristic smell.
  Starting in the early 1990s, various websites including The Anarchist Cookbook advertised recipes for homemade napalm. These recipes were predominantly equal parts gasoline and styrofoam. This mixture closely resembles that of napalm-B, but lacks a percentage of benzene.
  Napalm reaches burning temperatures of approximately 1,200 °C (2,200 °F). Other additives can be added, e.g. powdered aluminium or magnesium, or white phosphorus.
  In the early 1950s, Norway developed its own napalm, based on fatty acids in whale oil. The reason for this development was that the American-produced thickening agent performed rather poorly in the cold Norwegian climate. The product was known as Northick II.
caption: Napalm bombs explode after being dropped from a Republic of Korea Air Force F-4E Phantom II aircraft during a live-fire exercise.
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