Napalm

[1] A team led by chemist Louis Fieser originally developed napalm for the US Chemical Warfare Service in 1942 in a secret laboratory at Harvard University.

[2] Of immediate first interest was its viability as an incendiary device to be used in American fire bombing campaigns during World War II; its potential to be coherently projected into a solid stream that would carry for distance (instead of the bloomy fireball of pure gasoline) resulted in widespread adoption in infantry and tank/boat mounted flamethrowers as well.

It has been widely used from the air and from the ground, the largest use having been via airdropped bombs in World War II in the incendiary attacks on Japanese cities in 1945.

[9] The first use of napalm in combat was in August 1943 during the Allied invasion of Sicily, when American troops, using napalm-fueled flamethrowers, burned down a wheat field where German forces were believed to be hiding.

[11] Following a shortage of conventional thermite bombs, General Curtis LeMay, among other high-ranking servicemen, ordered air raids on Japan to start using napalm instead.

[14] A 1946 report by the National Defense Research Council claims that 40,000 tons of M69s were dropped on Japan throughout the war,[15][16] damaging 64 cities and causing more deaths than the atomic bombings of Hiroshima and Nagasaki.

[11] During the Allied siege of La Rochelle, napalm was dropped on the outskirts of the Royan pocket, inadvertently killing French civilians.

[22] British Prime Minister Winston Churchill privately criticized the use of napalm in Korea, writing that it was "very cruel", as US/UN forces, he wrote, were "splashing it all over the civilian population", "tortur[ing] great masses of people".

[10] Napalm became an intrinsic element of US military action during the Vietnam War as forces made increasing use of it for its tactical and psychological effects.

[10] The US Air Force and US Navy used napalm with great effect against all kinds of targets, such as troops, tanks, buildings, jungles, and even railroad tunnels.

[40]Napalm is lethal even for dug-in enemy personnel, as it flows into foxholes, tunnels, and bunkers, and drainage and irrigation ditches and other improvised troop shelters.

Even people in undamaged shelters can be killed by hyperthermia, radiant heat, dehydration, asphyxiation, smoke exposure, or carbon monoxide poisoning.