"You smell that? Do you smell that? Napalm, son. Nothing else in the world smells like that. I love the smell of napalm in the morning. You know, one time we had a hill bombed, for twelve hours. When it was all over I walked up. We didn't find one of 'em, not one stinkin' dink body. The smell, you know that gasoline smell, the whole hill. Smelled like - victory."
LTC William Kilgore, Apocalypse Now
Louis F. Fieser was best known for his research at Harvard University in organic chemistry which led to the synthesis of the hormone cortisone. He was slightly less known for his 1942 discovery: that aluminum naphthenate and aluminum palmitate made ideal thickeners for gasoline and other volatile hydrocarbons. As part of the war effort, Fieser helped the government design a thick, syrupy incendiary that was safer for friendly troops than gasoline. The two thickening compounds lent parts of their names to a space-age-sounding compound known as "napalm," which was first used in World War II, but later and more famously in Korea and Vietnam. "Napalm" is now used to mean any gasoline-based incendiary weapon with or without the original thickeners; newer additives include polystyrene, benzene, and other gelling agents. "Napalm B" (any napalm after WWII) was gasoline, polystyrene, benzene, and in some cases white phosphorous. From 1965 to 1969, Dow Chemical Corporation made Napalm for the U.S. military.
The original intent of napalm was an incendiary weapon which could be stored safely and deployed with minimal fuss for maximum damage. It was highly stable, tolerating temperatures from 150o F to -40o F, and thick enough that it was not easily dispersed by explosives. Deployed in a flamethrower or flame tank, napalm extended the range of formerly gasoline-based flame weapons from 30 yards to 150 yards... a football field and a half! Deployed from overhead in 165 gallon containers, a drum of napalm needed to be ignited with TNT or thermite, but once burning, very little could put out a napalm fire short of total combustion. In Vietnam, napalm was also used in land mines. A 55 gallon drum of napalm and a block of C4 would be connected to the trigger mechanism of a claymore mine, and upon activation, burning napalm would be sprayed for about a 50 meter radius. Because of its high burning temperature and tenacity, napalm was employed against pretty much every kind of target: vehicles, villages, cities, people, and trees...
In addition to serving as an defoliant, it's also an excruciatingly painful and often fatal exfoliant. A well-known Army marching song includes in its chorus the line "Napalm sticks to kids!" Images of napalm igniting in jungles, in villages, and on the people of Vietnam are still cultural icons of the 1970s. It is routinely cited along with Agent Orange as an example of American apathy to the cruelty of modern weapons. Napalm burns at over 5000o F, sticks to skin and clothing, and consumes oxygen quickly enough to asphyxiate victims near the flames but not engulfed in them. When dropped on secure bunkers, the ambient heat from napalm was enough to bake and dehydrate German WWII soldiers, giving rise to the German word "Bombenbrandschrumpfleichen," meaning "firebomb shrunken flesh". Napalm's hot-button reputation and America's changing doctrine made napalm obsolete after Vietnam.
On April 4, 2001, in a low-key ceremony at Fallbrook Naval Weapons Station, the U.S. military sent their last two existing canisters of napalm to be burned as additives at coal and natural gas plants in Texas and Louisiana.