Napalm (naphthenic palmitic acid) is an incendiary weapon invented in 1942. It is an extremely flammable, gasoline-based defoliant and antipersonnel weapon that can generate temperatures in excess of 2,000 degrees.
A large Napalm fire can create a wind system, a result of intense heat that is generated - causing vertical wind currents. Winds then feed more air into the fire, which increases the rate of combustion, thereby perpetuating itself. In some cases, that wind is called a "fire storm" and can sometimes reach up to 70 mph.
The product was conceived during World War I when gasoline was used in flamethrowers. The problem with gasoline was that it burned too quickly.
During World War II, Harvard University researchers, led by Dr. Louis Fieser, discovered that mixing rubber with gasoline made it a longer-burning product.
Rubber, however, was scarce at the time, so they had to find some other ingredient. They eventually mixed aluminum soap powder with gasoline (among other chemicals) to produce an extremely long-burning substance. The thickener turns the mixture into a thick jelly that flows under pressure and sticks to a target as it burns. Polystyrene and other polymers have since been used as a thickening agent.
That formula was used during the bombings of Germany and Japan. It was decided by the United Nations in 1980 that the substance's effects were too horrific, and a number of nations signed an accord to no longer use it. The United States did not sign the agreement, but claims to have officially destroyed its last canister in a public ceremony in 1991.
Napalm in Vietnam
Incendiary devices have been used as a tool of war since 1200 B.C. Perhaps the most well-known of such devices was “Greek fire," a weapon said to have been invented in the seventh century A.D. and used by Eastern Roman Emperors.
In Vietnam, the most frequently used container of napalm held about 130 gallons of gasoline with a solution of six percent napalm added. When dropped from “hedge-hopping" — those flying at an altitude of about 100 feet — the device was able to cover a surface with flames 270 feet long and 75 feet wide.
Frequently, when American military forces were becoming over-run in Vietnam, air strikes were called-in to help stabilize an escalating situation with Napalm, as well as other airborne explosives. However, the North Vietnamese Army (NVA), quickly caught on to this devastating weapon, and would "dig-in," finding shelter underground in thousands of connecting tunnel systems.
Napalm was sometimes delivered to its intended and unintended targets (a.k.a. "friendly fire") by flamethrowers mounted on U.S. Navy vessels plying the inland waterways of South Vietnam. Those boats were part of what was known as the "Brownwater Navy."
In Vietnam, napalm was as much a psychological weapon as killing weapon.