The HORRORS of the M2 Flamethrower in WW2

On the island of Iwojima, a man carrying this weapon could expect to live about 4 minutes, not 4 hours. 4 minutes. One Marine flamethrower unit on that black volcanic rock was destroyed at a casualty rate of 92%. The weapon weighed 70 lb. It threw fire for 9 seconds. And the men strapped to it were the single most hunted targets on the battlefield because every soldier on both sides understood exactly what it could do.

 But the flame was almost a mercy. Deep inside a sealed coral bunker 50 ft past the reach of any fire, Japanese soldiers were dying anyway. The weapon was eating their air. Burning napalm stripped the oxygen out of an enclosed cave in a matter of seconds and flooded it with carbon monoxide instead.

 You could be standing in total darkness untouched by a single spark and suffocate exactly where you stood. No door you could close, no corner you could hide behind, no depth you could dig to. This is the story of the M2 flamethrower and the nightmare it became for anyone trapped underground. Tarawa, November 1943.

 The Japanese had turned a coral speck barely 2 miles long into a fortress. 4,500 defenders waited inside coconut log bunkers, concrete pillboxes, and a single command bunker built to hold more than 150 men. Before the Marines landed, the United States Navy hammered the island with thousands of tons of shells. Officers predicted the garrison would be wiped out before a single boot touched the sand.

 76 hours later, Tarawa was taken. It cost the Marines roughly 1,000 dead. And it taught the United States a lesson it would pay for again and again across the Pacific. You cannot kill what you cannot reach. The Japanese had stopped defending the beaches. They went underground. Coral caves, interlocking tunnels, reinforced concrete pillboxes with walls feet thick connected by galleries that ran deep into the rock.

By the time the Americans reached Peleliu, a single ridge called the Umurbrogol hid more than 500 caves, many of them old phosphate mine shafts linked by tunnels and sealed behind sliding steel doors. On Iwo Jima, General Tadamichi Kuribayashi buried his 21,000 man garrison inside 11 miles of tunnels connecting some 1,500 rooms, gun positions and bunkers.

Nine months of naval bombardment did almost nothing to the network underneath. Against this, the standard tools of war simply failed. Naval guns and artillery could not punch through coral overhead cover or solid volcanic rock. Tank shells bounced off reinforced concrete. Rifle fire could not touch men hidden deep inside galleries.

 And grenades, the infantryman’s last resort, were beaten by one simple trick. The Japanese cut their cave entrances at a downward slant, so a grenade tossed inside would roll right back out and explode at the feet of the man who threw it. There was one more problem, and it was the worst. A position knocked silent was not a position destroyed.

 As one Marine officer put it after the solemns, a bunker reduced with grenades alone could come back to life an hour later and start killing again from behind your own lines. The Marines did not need something that suppressed a bunker. They needed something that went inside it. Something that filled every tunnel, chased around every corner, and left nothing alive to crawl back to the guns.

They needed fire. The first attempts were a disaster. In December of 1942 at Buna in New Guinea, American troops carried the brand new M1 flamethrower into combat for the first time. In the jungle humidity, the ignition failed. The weapon sputtered, refused to light, and threw raw fuel only a few feet before quitting.

 Men had crawled into rifle range of Japanese bunkers for nothing. The problem was the fuel. Raw gasoline atomizes in the air. It burns off in flight, so most of it is gone before it reaches the target. To hit anything, an operator had to close to within 10 or 15 yards of a position that wanted him dead.

 The fix came out of a Harvard laboratory. In 1942, a team of chemists led by Louis Fieser developed a gelling agent that turned thin gasoline into a thick, sticky jelly. They called it napalm, and it changed everything. Thickened fuel did not spray into mist. It held together in a coherent rod of fire, roughly three times the range of raw gasoline.

 It clung to whatever it hit like glue and kept burning. Woody Williams, the Marine who would become the most famous flamethrower operator of the war, described it plainly. It stuck to you like glue, and if you tried to brush it off, all you did was spread the burn. By 1944, the Chemical Warfare Service had perfected the design into the weapon that mattered. Officially, the M2-2.

 To the men who carried it, just the M2. Here is what a Marine actually hauled onto those beaches. Two fuel tanks holding 4 gallons of napalm-thickened gasoline. A third tank in the center filled with compressed nitrogen, not air, because nitrogen will not feed a fire if the system is hit. And a wand with a fresh ignition system, a small cylinder of five matchlit pyrotechnic cartridges that would actually fire in the wet heat of the Pacific, where the old electric spark had failed.

 Loaded, it weighed about 70 lb. Its effective range was 20 to 40 yd. And it carried at most 9 seconds of fire. 9 seconds. That was the entire account. A man carried 70 lb of liquid fire across open ground under machine gun fire to spend 9 seconds at a target close enough to spit on. And that rod of burning jelly did something the defenders never expected.

It did not stop at the cave mouth. It hit the walls and broke apart, splashing in burning droplets that ricocheted off stone and wrapped around corners. A soldier crouched in a side tunnel the operator could not even see was still showered in fire that had bent its way to him. But the flame, again, was only half the weapon. The other half was invisible.

 To understand why the M2 was so feared, you have to understand what it did to the air. When napalm burns, it is starving. The combustion is enormously hungry for oxygen, and inside a sealed space, it takes that oxygen from everywhere at once. A single 7-second burst fired into a bunker could render the entire atmosphere unbreathable in seconds.

 A modern peer-reviewed study published in the journal Military Medical Research in 2020 by David Van Wyke laid out the mechanism in clinical language. Burning napalm rapidly deoxygenates the surrounding environment, causing asphyxiation. Its byproducts include high levels of carbon monoxide and carbon dioxide, both of them toxic. Read that again slowly.

 The fire did not need to touch you. A defender standing 30, 40, 50 ft deep in a tunnel, around two corners in total darkness, well beyond the reach of any flame, would feel the air change. The oxygen vanished. Carbon monoxide took its place. And he would lose consciousness and die without a single burn on his body.

The Chemical Warfare Service knew this. And in one of the darker footnotes of the war, they tried to sell it as a virtue. Early on, they marketed the flamethrower as a kind of mercy sensei weapon, claiming it killed instantly through thermal shock and respiratory paralysis. Van Wyke’s research shows that claim was a euphemism, built on an incomplete understanding of how the weapon actually killed.

 There was nothing instant and nothing merciful about suffocating in the dark. For the men the fire did reach, the physics were worse. Napalm burns somewhere between 1,500 and 2,200 degrees Fahrenheit. Estimates of the flame tip on Williams’ own weapon run far higher, past 3,000 degrees. At those temperatures inside a sealed concrete box, the ambient heat alone climbs past anything a human body can survive in seconds.

 The gel sticks, and it does not stop. It burns through cloth, through skin, through the nerve endings that would otherwise register the pain. This was the trap the Japanese had built for themselves without knowing it. Every feature that made their fortifications strong, the depth, the seals, the dead-end galleries designed to trap attackers, became a death chamber the moment fire entered.

 The tighter the bunker, the faster the air died. There was, quite literally, nowhere to go. But if the bunker was a death trap for the men inside, the approach to it was a death sentence for the man with the flamethrower. Picture what an operator looked like out there. He stood taller than everyone around him, bent forward under 70 lb of tanks.

 When he fired, a column of orange flame and black smoke marked his exact position for every enemy gun in range. He moved slowly. He could not run. He could not hide. And both armies knew the flamethrower was the one weapon that could break a fortified line. So, they killed the operators first. Japanese tactical instructions, documented by the historian Brian Rig, explicitly ordered defenders to target flamethrower men above all others.

 Snipers and machine gunners watched for the stooped silhouette and the smokes. The moment a man lit up a bunker, he drew everything the enemy had. That is where the grim statistic comes from. On Iwo Jima, a Marine statistician later calculated the average combat life expectancy of a flamethrower operator at roughly 4 minutes.

 One unit lost 92% of its men. Eugene Sledge, the Marine who wrote the most honest memoir of the Pacific War, watched these men work on Peleliu. He called it the least desirable job open to any Marine. Carrying 70 lb of jellied gasoline through enemy fire, over broken ground, in brutal heat, to squirt flame into a cave mouth.

 An assignment, he wrote, that few survived, but all carried out with magnificent courage. There is a popular myth, fed by the movies, that you could blow up an operator with one bullet to the tanks. It is not true. The tanks were sealed under nitrogen with no oxygen inside to feed an explosion. Woody Williams said flatly they were virtually bulletproof, and that he felt machine gun rounds ricochet off the steel on his back as he crawled.

 The operators did not usually die in a fireball. They died the ordinary way, shot while doing the most dangerous job on the island. And no one did that job like a 5-ft 6 farm boy from West Virginia. If you are finding this one worth your time, take a second to subscribe. This channel covers the weapons and the men of the Second World War every week.

And the stories do not get much heavier than this one. Because on the 23rd of February 1945, that farm boy was about to spend 4 hours doing something almost no one survives even once. His name was Hershel Woodrow Williams. Everyone called him Woody. The Marines rejected him at first for being too short. He stood 5-ft 6.

When he finally got in and finally reached the Pacific, he was handed a weapon that had arrived in crates with no instructions for using it in combat. He learned the M2 flamethrower the hard way on Guam in the summer 1944. Then came Iwo Jima. Williams landed on the 21st of February with C Company, First Battalion, 21st Marines.

 Within 2 days, his company had been gutted. The 21st Marines lost 427 men out of just over 3,000 in 48 hours. His company was pinned by a belt of reinforced concrete pillboxes, interlocking machine guns that had already stopped the Sherman tanks cold. Every one of the six demolition and flamethrower men who had started under him was a casualty.

On the morning of the 23rd, with the company stalled and bleeding, his first sergeant asked him a simple question. Could he do anything with a flamethrower? Williams said he would try. Followed lasted 4 hours. Covered by just four riflemen, he went forward alone toward the pillboxes. He crawled up a rise while a Japanese machine gun hammered at him, the rounds ringing off the tanks on his back.

 He remembered the noise and the vibration, and that he just kept crawling forward. When he reached the first position, he found a way in. On top of one pillbox, he saw blue smoke rising from a pipe, a ventilation shaft the men inside were cooking. Williams climbed onto the bunker, shoved the nozzle down the pipe, and filled the inside with fire.

When a squad of Japanese soldiers charged him with bayonets, he met them with the wand. “A big ball of flame came out,” he said, “and the charge ended.” Each flamethrower carried only 9 seconds of fire. So, Williams burned one dry, crawled back through enemy fire to his own lines, dropped the empty pack, picked up a fresh one, and went back out.

 Again and again, he went through six flamethrowers. Two of the Marines covering him, Warren Bornholtz and Charles Fisher, were killed protecting him while he worked. By the end of those 4 hours, Hershel Williams had destroyed seven Japanese pillboxes single-handed. General Holland Smith later called the sector Williams cracked the very heart of the defense belt Kuribayashi had built on Iwo Jima.

 He was wounded on the 6th of March and evacuated. On the 5th of October 1945, President Truman placed the Medal of Honor around his neck. Williams never accepted that it belonged to him. He pointed to the two men who died covering him. “The medal,” he said, “belongs to them.” Williams was one man on one morning. But the pattern he proved played out across every island in the Pacific.

And the clearest proof of what the flamethrower changed comes from a single ridge on Peleliu, where the same Marines fought the same enemy on the same ground weeks apart with two different methods. In September of 1944, the 1st Marine Regiment under Colonel Chesty Puller assaulted the Umurbrogol head-on with infantry weapons, rifles, grenades, raw courage.

 In 5 days, Puller’s regiment took 1,749 casualties, close to 70% of its strength. One lieutenant lost 32 of the 41 men in his platoon. They cleared cave after cave and the caves kept coming back to life. Then the methods changed. The 5th Marines and the Army’s 81st Division reduced the same pocket with a different system, flame tanks, backpack flamethrowers, demolition teams.

 They stopped charging the caves and started methodically burning and sealing them one by one. The ground that had cost 1,700 casualties in 5 days was taken systematically at a fraction of the price. The numbers from that island reveal everything. On Peleliu, post-war statisticians calculated it took American forces more than 1,500 rounds of ammunition to kill each individual Japanese defender.

 Over 13 million rounds of rifle ammunition, more than 100,000 grenades, 150,000 mortar shells. That is what bullets and explosives achieved against men dug into rock. The flamethrower needed 9 seconds. By the end of Iwo Jima, American flame tanks were burning between 5,000 and 10,000 gallons of napalm a day. Captain Frank Caldwell of the 26th Marines said it plainly.

In his view, it was the flame weapon more than any other supporting arm that won the battle. But there is a cost to a weapon like this that no statistic captures. Woody Williams carried it for the rest of his life. He spoke decades later about the smell. He said there is no odor on earth like burned flesh and that it bothered him for years.

 With a flamethrower, he said, “You kill people up close. You are there for it.” He drank to forget it. He said he could not forgive himself for taking so many lives in such a horrible way until he found his faith and finally made some kind of peace. Eugene Sledge, who only watched, was appalled the first time he saw a flamethrower in training, realizing it could burn a man to death.

He used it anyway because on those islands it was often the only thing that worked. In 1978, the United States quietly removed flamethrowers from its arsenal. No treaty forced the decision. No enemy demanded it. The military simply concluded the weapon’s usefulness no longer justified the horror of its image.

 The Chemical Warfare Service once called it a mercy weapon. A clean death, they said. Thermal shock, respiratory paralysis, it was neither clean nor merciful. It was a machine that could reach a man through solid rock, around corners he believed were safe, and take the air out of his lungs in the dark without ever touching him.

 That was the M2 flamethrower, the weapon that broke the Pacific one bunker at a time. And the men who carried it bought every yard of that ground with about 4 minutes of their own lives.