It sticks. That is the first thing anyone who survived it will tell you. Unlike gasoline, which splashes and runs, napalm was engineered to behave like a living thing that refuses to let go. When we ask what did napalm do, we aren't just talking about chemistry or military tactics. We are talking about a substance designed by Harvard scientists to turn the air into an oven and the ground into a trap.
It’s brutal.
If you’ve seen the iconic "Napalm Girl" photograph from 1972, you’ve seen the aftermath. But the technical reality of how it works is even more chilling than the imagery. Basically, napalm is a mixture of a thickening agent and petroleum. In its original form, developed by chemist Louis Fieser during World War II, it used aluminum salts of naphthenic and palmitic acids. That’s where the name comes from: Naphthenic and palmitic.
The Chemistry of Sustained Burning
In the early days of flamethrowers, soldiers used straight gasoline. It was dangerous and inefficient. It burned too fast. Most of it evaporated before it even hit the target. The military needed something that could be "projected"—shot out of a nozzle or dropped in a canister—and remain burning for a long time.
Napalm solved this.
By turning fuel into a thick, jelly-like goo, it could be fired over long distances without breaking up in mid-air. Once it hit a surface, it stayed there. If it hit a person, they couldn't wipe it off. Rubbing it only spread the fire over a larger surface area of the skin. It burned at temperatures between $800°C$ and $1,200°C$. To put that in perspective, that is more than hot enough to melt aluminum or steel under specific conditions.
Honestly, the sheer heat wasn't the only killer. It also sucked the oxygen right out of the room. In enclosed spaces like bunkers or tunnels, many people didn't die from burns. They suffocated. The fire consumed the oxygen so rapidly that it created a localized vacuum, often replacing breathable air with carbon monoxide.
What Napalm Did in World War II and Beyond
Most people associate this weapon with Vietnam, but its most devastating use actually happened decades earlier. In March 1945, the U.S. launched Operation Meetinghouse. This was the firebombing of Tokyo. Over 300 B-29 bombers dropped roughly 1,600 tons of incendiaries, much of it napalm-filled M69 bombs.
The results were catastrophic.
Because Tokyo was largely built of wood and paper, the napalm created a "firestorm." The heat was so intense it created its own wind system, sucking people into the flames. About 100,000 people died in a single night. That is more than the immediate death toll of either Hiroshima or Nagasaki. It literally turned the city into a furnace.
During the Korean War, the U.S. used even more of it. Roughly 32,000 tons. It was effective against the rugged terrain and deep dugouts where traditional explosives failed. But the psychological toll was arguably higher than the physical damage. Soldiers feared it more than bullets. There is a specific kind of terror reserved for a weapon you cannot outrun or extinguish with water.
The Vietnam Era and "Napalm-B"
By the 1960s, the formula changed. This is what most historians refer to as Napalm-B. Unlike the original version, this used polystyrene, benzene, and gasoline. It was actually safer for soldiers to handle because it required a specific igniter to catch fire—it wouldn't just go off if someone smoked a cigarette near it.
But for those on the receiving end? It was worse.
Napalm-B burned for up to ten minutes. The original stuff usually fizzled out in thirty seconds to a minute. This new version stuck to surfaces even better. It was used to clear landing zones for helicopters and to flush out North Vietnamese Army (NVA) troops from the dense triple-canopy jungle.
The Medical Nightmare of Incendiary Injuries
When we look at what napalm did to the human body, the "lucky" ones died instantly from asphyxiation or shock. The survivors faced a level of trauma that most field hospitals weren't equipped to handle.
- Fourth-degree burns: Napalm often burned through the skin and muscle all the way to the bone.
- Carbon Monoxide Poisoning: Even those not touched by the liquid often suffered permanent brain damage from inhaling fumes.
- Infection: Because the burns were so deep and covered such large areas, sepsis was almost inevitable in a jungle environment.
- Contractures: As the skin healed, it would shrink and tighten, often leaving limbs fused in place or making it impossible for victims to close their eyes or mouths.
The pain was described as "unbearable" because the jelly would continue to burn even when submerged in water. Phosphorus, often added as an igniter, would reignite the moment it was exposed to air again.
Why It Isn't Used the Same Way Today
You don't see napalm in the news much anymore. There’s a reason for that. In 1980, the United Nations passed a convention that prohibited the use of incendiary weapons against civilian populations. While it’s technically legal to use against military targets under certain conditions, the international "stigma" is massive.
The U.S. military eventually moved away from it, replacing it with things like the Mark 77 firebomb. Officials often argue these aren't "napalm" because the chemical composition is different (using kerosene-based fuel), but the effect is largely the same. It’s a semantic distinction that doesn't mean much to someone on the ground.
Understanding the Legacy
Napalm changed the way we view "clean" warfare. It proved that technology could be used to create something so horrifying that it actually shifted public opinion. The images coming out of Vietnam—of children scorched by misdirected strikes—did more to end the war than many political protests.
It represents the intersection of scientific brilliance and human cruelty. Louis Fieser, the man who invented it, reportedly felt no guilt. He viewed it as a tool to save American lives by ending wars faster. History, however, has a much more complicated view of that trade-off.
Actionable Insights for History and Ethics Research
If you are researching the impact of incendiary warfare or the ethics of military technology, consider these specific avenues for deeper understanding:
1. Study the Records of the Dow Chemical Protests
Research how the manufacturing of napalm by Dow Chemical led to the first major campus protests in the U.S. This is a primary example of corporate social responsibility (or the lack thereof) becoming a public flashpoint.
2. Examine the 1980 UN Convention on Certain Conventional Weapons (CCW)
Look at Protocol III. It specifically outlines the legal restrictions on incendiaries. Understanding the loopholes in this protocol explains why "napalm-like" weapons are still technically in global inventories.
3. Read First-Hand Accounts from the 1st Marine Division
The records from the Battle of Chosin Reservoir in the Korean War provide some of the most detailed accounts of napalm's tactical use in extreme cold, highlighting how it was used to create defensive perimeters.
4. Analyze the Medical Transition in Burn Care
Modern burn surgery and the use of silver sulfadiazine actually evolved in part due to the need to treat the complex, deep-tissue injuries caused by napalm and white phosphorus during the mid-20th century.