The Fires of War: Thermite, Napalm, and Other Incendiaries

^{National Archives from Bureau of Medicine and Surgery French soldiers repel German attack with flamethrowers.}

On the night of March 9, 1945, as the B 29s took off from Guam, war was raging everywhere. In Europe that day, American forces had taken the Ludendorff Bridge at Remagen, crossing the border of Germany for the first time. The Red Army had entered Germany and had trapped half a million German troops in a pocket against the Baltic Sea, but there were still months of fighting ahead. In the United States, the American Office of War Information was desperately trying to perpetuate the myth, based on Roosevelt’s promise to Churchill, that American forces were concentrating on defeating Germany first, after which they would turn to Japan.

Actually, there was no such concentration on Germany by American forces.

That propaganda line, politically correct at the time, has unfortunately been accepted by some later writers. That makes it sound as if Japan was a paper tiger that collapsed like a punctured balloon as soon as we were able to turn away from Germany. And that supposition ignores all the toil, blood, and hero‑ism of the American forces that pushed Japan almost to the breaking point while their contemporaries were helping to defeat Germany. The British forces did concentrate on Germany, certainly. Germany was a near, clear‑and‑present danger. But, although the largest part of the U.S. Army was in the European and Mediterranean theaters, almost all of the major ships of the U.S. Navy – aircraft carriers, battleships, cruisers, and submarines, and most of the Marine Corps – were in the Pacific and had been for three years. Guam itself, the base of these super‑heavy B 29 bombers, had been retaken from the Japanese less than a year before this. At the same time, at the Battle of the Philippine Sea (also known as the Great Marianas Turkey Shoot), the U.S. Navy had broken the back of Japanese naval air forces and dealt a heavy blow to the Imperial Navy. A few months later, on October 24 and 25, 1944, the United States struck an even heavier blow at the Battle of Leyte Gulf. Japan lost four aircraft carriers, three battleships, 10 cruisers, and nine destroyers as well as 500 planes, and U.S. forces began the reconquest of the Philippines. They had gone from there to Iwo Jima on the doorstep of Japan – almost, in fact, one of the Japanese home islands. By this time, Japan had no airframe factories, almost no shipping, hardly any oil, and hardly any planes on the home islands.

The B 29s soared over the Pacific on a route that had been used many times before. They were heading for a target so far away such a bombing mission would have been unthinkable early in the war. Enough 29s had already flown this route, though, to have wiped out some of Japan’s strategic industries such as airframe factories and oil refineries. The Japanese had managed to disperse other industries all around their country, but that didn’t matter now. The Americans were after cities. Tonight’s target was the huge Tokyo‑Yokohama metropolitan area.

The bombers swooped to low altitude as they approached the Japanese coast and unloaded their deadly cargo over the port city of Yokohama and the Japanese capital, Tokyo, then returned to Guam after experiencing hardly any resistance. Behind them, 16 square miles of homes and businesses were ablaze.

They had created a fire storm – the biggest one in history.

A fire storm occurs when a conflagration becomes so big and hot that it creates a powerful updraft over the center of the fire, consumes all the oxygen in the affected area, and draws so much cool air to the center of the fire that winds reach gale force. The winds make the fire more intense. The heat in Tokyo was so intense that the water in the city’s canals boiled. In places, the fire took all the oxygen out of the air. Many of those caught in the firestorm, even though sheltered from the flames, suffocated for lack of oxygen. In this raid, some 86,000 people – almost all civilians (men, women, and children) – died.

In June 2004, John Yoo, a law professor explaining some memos (which he helped write) defending the use of torture on prisoners in the Iraq War, said,

“This is an unprecedented conflict with a completely new form of enemy that fights in unconventional ways that violate the very core principles of the laws of war by targeting civilians.”

The weapon that made possible conflagrations such as the Tokyo‑Yokohama fire and the fires that destroyed all of the largest cities of Japan was based on an incendiary substance known and used by every American: gasoline. It was jel‑lied by mixing it with aluminum naphthenate, a naphtha‑based soap, and aluminum palmate, a palm‑oil‑based soap. The thickened gasoline clings to whatever it touches and burns more fiercely. It was also used in American flamethrowers during World War II. Because of the thickening, flamethrowers projected in a narrow stream with greater range than would have been possible with gasoline.

The jet of fire could be made to ricochet around corners. Newer fire bombs use a liquid, not a gel, called napalm B, composed of polystyrene, benzine, and gasoline. It is said to burn three times longer than the older mixture and cause more destruction.

The idea of napalm bombs came from fighter‑bomber pilots who discovered that if one of their auxiliary gas tanks were dropped while still loaded, it ignited spontaneously. That made it a potentially deadly weapon, and substitut‑ing napalm for aviation gas made it even more deadly. Most napalm bombs were quite large, in contrast to the thermite bombs that initiated this horrible form of warfare, first by the Germans, then by the British.

Thermite, too, is a combination of common materials – powdered aluminum and ferric oxide – better known as rust. Neither component, though, is generally considered a fire‑starter. Thermite had been used to an extent in the First World War when German zeppelins bombed cities. At that time, it formed the center of a cone of resinous material bound with tarred rope. In the Second World War, the Germans used thousands of 2‑pound bombs that looked like a magnesium rod with tail fins. Each consisted of a thick‑walled casing of magnesium with a core of thermite. The thermite ignited the magnesium, which burned so intensely it could not be extinguished with water. Water only made it burn more fiercely, because the hot magnesium took oxygen from the water, which, of course, is a compound of hydrogen and oxygen. Air raid wardens were encouraged to cover the burning bombs with sand or else spray them with a fine spray of water to make them burn themselves out more quickly without spread‑ing the fire. The longer the bomb burned, the more likely it was to cause a bigger fire. Thermite and magnesium burned hot enough to melt any metal and pulverize several inches of concrete.

When the British began bombing German cities, they turned thermite against its former users and added some refinements. One was a bomb that parachuted to Earth. When it landed, the tail blew off, then it forcibly ejected seven thermite bombs over a period of 10 minutes while thermite in its nose burned where it landed.

Artillery use a variety of incendiary shells. Some contain thermite, some white phosphorus, some other chemicals. Small arms also shoot incendiary ammunition. Tracer bullets are incendiaries, so were what the British called

“Buckingham bullets,” which had small amount of white phosphorus or an explosive in the nose. One high‑tech incendiary is depleted uranium solid shot, widely used by U.S. forces against armor. DU, as it’s called, gives off sparks when it strikes something hard, such as armor plate. The sparks have an extremely high temperature, which makes them likely to ignite anything inflammable, such as gasoline vapor in the interior of a tank (see Chapter 49).

Fire has been a weapon of war for long before Greek fire, probably for as long as there has been war, but it never gained the importance it did in World War II with the advent of thermite and napalm aerial bombs.