“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 12 hours. When it was all over, I walked up. We didn’t find one of ‘em, one stinkin’ dink body. But that smell, that gasoline smell? The whole hill. Smelled like…victory.”

These iconic words, spoken by the character of Lieutenant Colonel William Kilgore in 1979’s Apocalypse Now, are the stuff of film legend, and helped to cement in the minds of moviegoers our modern collective image of the Vietnam War. More than any other weapon, napalm has become inextricably linked with the war, symbolizing its wanton, industrialized cruelty and ultimate futility. But what is napalm, anyway? Who invented it, how does it work, and what is it about this weapon that made its creator disown his own invention and turned an entire anti-war movement against a single company? Well, load up your ‘Thud’ with a load of ‘snake and nape’, and let’s get some, shall we?

Napalm emerged from a dramatic shift in U.S. strategy during the Second World War. In the 1930s, various air forces around the world developed the doctrine of precision strategic bombing, wherein heavy bomber aircraft would be used to carry out precision high-altitude strikes on key enemy infrastructure like factories, power plants, and railways. This would effectively cripple the enemy’s ability to wage war, bringing the conflict to a swift and decisive end. Military planners were confident that precision bombing would make wars cleaner, faster, and more humane, eliminating altogether the need for armies to meet on the battlefield.

The outbreak of the Second World War, however, revealed this strategy to be fatally flawed. At the time precision bombing doctrine was developed, military strategists assumed that the new generation of all-metal monoplane bombers would be able to outrun and out-climb anything the enemy could throw at them, and that any remaining threats could be easily neutralized by arming the bombers with an array of defensive machine guns. Thus, it was believed, bombers would be able to attack their targets with near-impunity, inspiring the not-at-all-hubristic motto “The bomber will always get through.” By 1939, however, fighter and anti-aircraft artillery technology had advanced sufficiently that these once seemingly “untouchable” bombers were now sitting ducks, with the first British daylight raids against Nazi-occupied Europe suffering horrific casualties. In response, the British switched to a strategy of bombing at night. While this was effective at protecting bombers from enemy aerial defences, it also made it nearly impossible for bombardiers to accurately identify features on the ground, resulting in most bombs landing kilometres away from their intended targets. Realizing that their bombers were only useful against city-sized targets, the British once again switched tactics and developed the controversial doctrine of “area bombing.”

Area bombing effectively obliterated the distinction between combatants and civilians which had defined previous wars. Rather than striking specific military targets, bombers would now target entire cities and towns. By destroying the homes of factory workers, the logic went, the enemy’s ability to produce war materiel could be crippled. Furthermore, repeated bombing would eventually break civilians’ will to fight, causing them to rise up against their government and sue for peace. As such widespread destruction could not easily be inflicted using conventional explosives, the British took to using incendiary weapons to set cities ablaze. In a procedure that the Royal Air Force perfected to a near-science, aircraft called pathfinders used precision navigation equipment to drop flares onto the middle of the target city, marking the drop point for the following bomber stream. The first wave of bombers would then drop heavy explosive charges called blockbusters to blow the roofs off buildings, allowing incendiary bombs dropped by subsequent waves to penetrate into the buildings’ flammable interiors. This strategy was used to devastating effect in July 1943 during the Operation Gomorrah raid on the German city of Hamburg. A combination of firebombing tactics and unusually dry weather led to the formation of a firestorm, a 460 metre tall vortex of flame that generated 45 kilometre-per-hour winds, sucking the air out of air raid shelters and sweeping citizens off their feet into the inferno. By the time the raid was over, 60% of the city had been destroyed and 40,000 citizens killed.

When the United States entered the war in late 1941, they were initially horrified by British area bombing tactics and vowed to pursue precision daylight raids. Thus began the round-the-clock bombardment of Germany, with the USAAF bombing by day and the RAF by night. Soon, however, the Americans learned the same lesson the British had earlier in the war, as daylight bombing raids over heavily-defended German cities suffered ever-mounting losses. Eventually, the USAAF came around to the doctrine of area bombing, and began conducting joint firebombing raids alongside the British.

Early in the war, U.S. bombers carried incendiary bombs similar in design to their British counterparts, fuelled by various mixtures of white phosphorus -which ignites on contact with air – magnesium, and thermite – a mixture of iron oxide and aluminium powder that burns at temperatures up to 2500 degrees Celsius. In 1944, however, a new type of incendiary bomb began appearing in USAAF depots, filled with a potent new substance called “napalm”. Napalm was invented in July 1942 by a team of Harvard University chemists led by Louis F. Fieser. While working for the National Defense Research Committee chemical weapons division, Fieser and his colleagues were tasked with investigating the potential military applications of divinyl acetylene, a synthetic drying oil used in paints and coatings. A series of industrial accidents had revealed that exposing this compound to oxygen could cause it to violently explode, making it a promising candidate for development into a new explosive. The team built a variety of experimental bombs filled with divinylacetylene and set them off using small gunpowder charges. As Fieser later noted, the results were intriguing:

“We noticed also that when a viscous gel burns it does not become fluid but retains its viscous, sticky consistency. The experience suggested the idea of a bomb that would scatter large burning globs of sticky gel.”

This was not a new idea. Indeed, early in the war both the British and Americans had produced a number of simple molotov cocktail-style grenades consisting of glass bottles filled with gasoline, benzene, and white phosphorus. To thicken the mixture and make it stick better to a target, pieces of raw rubber were dissolved in the gasoline. This type of gasoline-rubber mixture was also used in the standard American air-dropped incendiary bomb, the M47. But, there was a problem: following their conquest of southeast Asia, the Empire of Japan controlled most of the world’s rubber supply, meaning Fieser and his team had to find an alternate means of thickening gasoline. After much experimentation, they hit upon a pair of compounds, aluminium naphthene and aluminium palmitate, which when mixed with gasoline produced a sticky, highly flammable gel. Fieser dubbed the mixture napalm, a contraction of the naphthene and palmitate thickening agents.

On July 4, 1942, Fieser’s team tested their creation by detonating an M-47 bomb filled with napalm in the middle of a puddle in a soccer field outside Harvard’s football stadium – because, why not? As Fieser later recalled:

“The performance, from the start, was most impressive. The high explosive cuts the inner well into the ribbons and opens the casing down the entire length. Pieces of phosphorous are driven into the gel, and large, burning globs are distributed evenly over a circular area about 50 yards in diameter.”

The U.S. Army Chemical Warfare Service tested napalm at the Edgewood Technical Arsenal in Maryland and the Dugway Proving Grounds in Utah, where exact replicas of typical German and Japanese housing was built to evaluate various aerial weapons. Napalm performed exceptionally well, demonstrating numerous advantages over older incendiary weapons. Unlike thermite, magnesium, or oil-fuelled bombs, napalm scattered over a wide area and stuck firmly to the target, increasing the chances of ignition. And unlike white phosphorus, napalm could not spontaneously ignite, making it safer for ground crews to handle. Napalm also had applications outside of aerial warfare – especially in flamethrowers. While flamethrowers had been used during the First World War, the straight gasoline or diesel fuel they used tended to disperse rapidly, limiting their effectiveness. Napalm, however, formed a solid, concentrated stream when projected from flamethrowers, greatly enhancing their range and accuracy.

Napalm was first deployed in flamethrowers on December 15, 1943 during the U.S. invasion of Papua New Guinea, where it proved highly effective against Japanese pillboxes and bunkers. Interestingly, when U.S. troops entered captured bunkers, they found dead Japanese soldiers without any burns. They soon determined that the main effect of flamethrowers was to flood the bunkers with carbon monoxide gas, killing the occupants instantly.

Aerial napalm bombs were first used in Europe in December 1943 in Sicily and in the Pacific in 1944 during assaults on the islands of Ponhpei and Tinian. But the greatest and most devastating uses of napalm during the war would take place in 1945. On February 14 and 15 of that year, 1,299 RAF and USAAF aircraft dropped 3,900 tons of explosive and incendiary bombs – including 740 tons of napalm – on the German city of Dresden. As in Hamburg two years earlier, the bombings ignited a ferocious firestorm which consumed 6.5 square kilometres of the city and killed an estimated 25,000 people. The bombings also ignited a storm of controversy that rages to this day over whether Dresden was a vital enough target to justify such high civilian casualties, with many arguing that the operation constituted a war crime. But even this destruction would be dwarfed only one month later by Operation Meetinghouse, in which 279 USAAF bombers dropped 14,000 tons of M69 napalm cluster bombs on the Japanese capital of Tokyo. Unlike in Germany, Japanese cities were built mainly of wood, allowing the flames to spread out of control. The resulting firestorm destroyed nearly a quarter of the city and killed an estimated 100,000 people – more than the atomic bombings of Hiroshima and Nagasaki combined – making Operation Meetinghouse the single deadliest air raid in history.

After the war, the use of napalm spread around the world, the weapon being used in the Greek Civil War, French colonial wars in Indochina and Algeria, by dictator Fulgencio Batista against rebel forces in Cuba, and in the Korean War. Indeed, napalm was one of the favourite weapons of the U.S. forces in Korea, with 635,000 tons being dropped during the conflict – nearly four times the amount dropped on Japan during the entire Second World War. As in that war, however, the use of napalm in Korea proved controversial, with U.S. Air Force, Navy, and Marine Corps pilots being accused of the indiscriminate bombing of civilians. For instance, on January 20, 1951, U.S. aircraft conducted a firebombing raid on a cave near Yongchoon, 144 kilometres southeast of Seoul, believing that North Korean forces were hiding inside. However, the cave was actually sheltering South Korean refugees, an estimated 300 of whom were killed in the attack. American pilots were reported as regularly firebombing groups of civilians on the suspicion they were harbouring North Korean infiltrators, while the current North Korean government claims that more than 8,000 civilians were killed during repeated U.S. napalm strikes on the North Korean capital of Pyongyang.

No conflict, however, is more closely associated with napalm than the Vietnam War. The dense jungles of Vietnam, Laos, and Cambodia provided excellent cover for North Vietnamese Army and Viet Cong troops, frustrating American and South Vietnamese efforts to locate and destroy enemy forces. Napalm proved an ideal weapon for clearing large areas of land, and was heavily deployed from February 1962 onwards. Between 1963 and 1973, more than 400,000 tons of napalm were dropped on Indochina, reaching peak use in April 1972. By this time, the weapon’s composition had changed, making it “napalm” in name only. This new composition, dubbed “Napalm B”, replaced the aluminium naphthate and palmitate thickeners with polystyrene, making it cheaper to manufacture and easier to ignite. It also burned for longer – up to 10 minutes compared to 15-30 seconds for the original composition.

Yet for such a simple weapon, the effects of napalm were horrific. Due to its stickiness and high burning temperatures, napalm inflicted burns that were too deep and severe to heal. Medics treating victims of napalm attacks described burned flesh that looked like “swollen, raw meat” and eyelids so badly burned they could no longer be shut. As you might imagine, the highly-publicized nature of history’s first “television war” meant that images of these ghastly injuries soon reached the American public, sparking mass outrage. The first such images, which appeared in Ramparts magazine in January 1967, convinced civil rights leader Martin Luther King Jr. to publicly oppose the war, and triggered large student protests at the University of Wisconsin. But the photo that did the most to galvanize public opinion against napalm – and the war as a whole – was taken by Associated Press photographer Nick Ut on June 8, 1972. The photo, which won Ut a Pulitzer Prize and has become one of the most enduring images of the Vietnam War, shows a group of Vietnamese children – including 9-year-old Phan The Kim Phuc – fleeing the village of Trang Bang, which had just been firebombed by South Vietnamese aircraft. The photo inspired the popular protest slogan “NAPALM STICKS TO KIDS” and focused outrage on the main manufacturer of napalm: Midland, Michigan-based firm Dow Chemical.

Ironically, Dow Chemical was ranked only 75th on a list of top U.S. military contractors, and prior to 1965 were mostly known as the manufacturers of Saran Wrap kitchen cling film. Thanks to napalm, however, they would quickly become one of the best-known corporations in the United States – and among the most hated. Anti-war activists protested outside Dow factories and spat on, attacked, and chased away Dow recruiters on college campuses, calling then “baby killers.” In response, Dow management first asked the Pentagon to take full responsibility for the use of napalm in Vietnam, absolving the company from blame. When this did nothing to quiet protests, the company briefly considered halting the production of napalm. After weighing the financial and moral risks, however, Dow decided that its main responsibility was to the government, and manufacture continued unabated. Instead, Dow embarked on a massive public relations campaign, releasing promotional films and pamphlets and stepping up recruitment efforts on campuses. Surprisingly, the campaign achieved some success; for many students, being interviewed by Dow Chemical was seen as an ironic “badge of honour”, and interviews actually increased over the next several years. But even after the company stopped producing napalm in 1969, the protests continued, the weapon and the company having become inextricably linked. Decades later, Dow would become embroiled in controversy once again over another one of its products: the herbicide Agent Orange, whose widespread use in Vietnam has been blamed for thousands of cases of birth defects and cancer.

The use of napalm in the Vietnam War so disgusted its inventor, Louis Fieser, that in 1967 he revised his autobiography to remove all mention of his most famous creation. Yet despite this public relations disaster, napalm continued to be used around the world for decades. It was deployed by both sides during the Six-Day War in 1967 – including in Israel’s controversial attack on the U.S. spy ship USS Liberty – the Yom Kippur War of 1973, and the Israeli-Lebanon war in the 1980s. It was used by Nigerian government forces against Biafran separatists in the 1960s, by Portuguese colonial forces in Angola in the 1970s, Argentine forces against the British during the 1982 Falklands War, and Serbian and Croatian forces during the Yugoslav Wars of the 1990s – among others. In 1980, however, continuing protests over its use led the United Nations to restrict the use of napalm and other incendiaries against personnel via Protocol III of the Convention on Certain Conventional Weapons, which states:

1. It is prohibited in all circumstances to make the civilian population as such, individual civilians or civilian objects the object of attack by incendiary weapons.

2. It is prohibited in all circumstances to make any military objective located within a concentration of civilians the object of attack by air-delivered incendiary weapons.

3. It is further prohibited to make any military objective located within a concentration of civilians the object of attack by means of incendiary weapons other than air-delivered incendiary weapons, except when such military objective is clearly separated from the concentration of civilians and all feasible precautions are taken with a view to limiting the incendiary effects to the military objective and to avoiding, and in any event to minimizing, incidental loss of civilian life, injury to civilians and damage to civilian objects.

4. It is prohibited to make forests or other kinds of plant cover the object of attack by incendiary weapons except when such natural elements are used to cover, conceal or camouflage combatants or other military objectives, or are themselves military objectives.

Due to such regulations and shifting military doctrine regarding collateral damage, the use of napalm and incendiaries by US forces has declined precipitously after Vietnam. As Matthew Evangelista, professor of History and Political Science at Cornell University explains:

“The norms governing bombing – and particularly the harm it imposes on civilians – have evolved considerably over a century: from deliberate attacks against rebellious villagers by Italian and British colonial forces in the Middle East to institutionalized practices seeking to avoid civilian casualties in the U.S. counterinsurgency and antiterrorist wars of today. In between, the strategic bombing campaigns of World War II caused great civilian destruction through fire-bombing of cities and, ultimately, the atomic attacks against Hiroshima and Nagasaki.”

Nonetheless, napalm-style incendiaries continue to be used under limited circumstances. During Operation Desert Storm in 1991, U.S. Marine Corps aircraft used incendiaries to ignite oil-filled trenches constructed by the Iraqis as an anti-invasion barrier, while in 2001and 2003 U.S. aircraft used incendiaries against Taliban forces in Tora Bora, Afghanistan, and during the invasion of Iraq. In all three cases the weapon used was not a traditional napalm canister but a 340-kilogram bomb called the Mark 77, which is filled with a mixture of kerosene, oxidizers, and white phosphorus. This composition is easier to ignite, harder to put out, and, according to the Pentagon, has less of an environmental impact that styrene-based napalm, which releases toxic and carcinogenic compounds as it burns.

Yet despite this more limited doctrine for the use of incendiaries, American officials refrain from using the term “napalm” and refer to the weapons simply as “Mark 77s” – demonstrating that the Vietnam War continues to cast a long shadow over the United States military.

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