Open main menu

A fire or light ball from the 17th century from Veste Coburg, Germany
Essay on fireworks for spectators and for warfare by Jean-Charles Perrinet d'Orval, 1745

Incendiary weapons, incendiary devices, incendiary munitions, or incendiary bombs are weapons designed to start fires or destroy sensitive equipment using fire (and sometimes used as anti-personnel weaponry), that use materials such as napalm, thermite, magnesium powder, chlorine trifluoride, or white phosphorus. Though colloquially often known as bombs, they are not explosives but in fact are designed to slow the process of chemical reactions and use ignition rather than detonation to start and or maintain the reaction. Napalm for example, is petroleum especially thickened with certain chemicals into a 'gel' to slow, but not stop, combustion, releasing energy over a longer time than an explosive device. In the case of napalm, the gel adheres to surfaces and resists suppression.

Pre-modern historyEdit

A range of early thermal weapons were in use ancient and early armies using hot pitch, oil, resin, animal fat and other similar compounds. Substances such as quicklime and sulfur could be toxic and blinding. Incendiary mixtures, such as the petroleum-based Greek fire, were launched by throwing machines or administered through a siphon. Sulfur- and oil-soaked materials were sometimes ignited and thrown at the enemy, or attached to spears, arrow and bolts and fired by hand or machine. Some siege techniques—such as mining and boring—relied on combustibles and fire to complete the collapse of walls and structures.

Towards the latter part of the period, gunpowder was invented, which increased the sophistication of the weapons, starting with fire lances.

Development and use in World War IEdit

An incendiary bomb dropped on Southend-on-Sea in 1916



Development and use in World War IIEdit

A German World War II 1 kg incendiary bomb



The German Luftwaffe started the war using the 1918-designed one-kilogram magnesium alloy B-1E Elektronbrandbombe; later modifications included the addition of a small explosive charge intended to penetrate the roof of any building which it landed on. Racks holding 36 of these bombs were developed, four of which could, in turn, be fitted to an electrically triggered dispenser so that a single He 111 bomber could carry 1,152 incendiary bombs, or more usually a mixed load. Less successful was the Flammenbombe, a 250 kg or 500 kg high explosive bomb case filled with an inflammable oil mixture, which often failed to detonate and was withdrawn in January 1941.[9]

In World War II, incendiaries were principally developed in order to destroy the many small, decentralised war industries located (often intentionally) throughout vast tracts of city land in an effort to escape destruction by conventionally aimed high-explosive bombs. Nevertheless, the civilian destruction caused by such weapons quickly earned them a reputation as terror weapons with the targeted populations. The Nazi regime began the campaign of incendiary bombings at the start of World War II with the bombing of Warsaw, and continued with the London Blitz and the bombing of Moscow, among other cities. Later, an extensive reprisal was enacted by the Allies in the strategic bombing campaign that led to the near-annihilation of many German cities. In the Pacific War, during the last seven months of strategic bombing by B-29 Superfortresses in the air war against Japan, a change to firebombing tactics resulted in the death of 500,000 Japanese and the homelessness of 5 million more. Sixty-seven Japanese cities lost significant areas to incendiary attacks. The most deadly single bombing raid in history was Operation Meetinghouse, an incendiary attack that killed some 100,000 Tokyo residents in one night.

British I.B. 4-lb. Mk IV [10] type incendiary bomb. Top: complete device, nose is red, Middle: dud found without the tin plate tail, Bottom: the remains after burning. RAF Bomber Command dropped 80,000,000 of these 4 lb incendiary bombs during World War II. The 4 lb bomb was also used by the US as the "AN-M50".

The 4 lb (1.8 kg) incendiary bomb, developed by ICI, was the standard light incendiary bomb used by RAF Bomber Command in very large numbers, declining slightly in 1944 to 35.8 million bombs produced (the decline being due to more bombs arriving from the United States). It was the weapon of choice for the British "dehousing" plan. The bomb consisted of a hollow body made from aluminium-magnesium alloy with a cast iron/steel nose, and filled with thermite incendiary pellets. It was capable of burning for up to ten minutes. There was also a high explosive version and delayed high explosive versions (2–4 minutes) which were designed to kill rescuers and firefighters. It was normal for a proportion of high explosive bombs to be dropped during incendiary attacks in order to expose combustible material and to fill the streets with craters and rubble, hindering rescue services.

Avro Lancaster bomb bay showing later mix of 4,000-pound "Cookie" blast bomb and 12 Small Bomb Containers each containing 236 4 lb incendiaries.

Towards the end of World War Two, the British introduced a much improved 30 lb (14 kg) incendiary bomb, whose fall was retarded by a small parachute and on impact sent out an extremely hot flame for 15 ft (4.6 m); This, the Incendiary Bomb, 30-lb., Type J, Mk I,[10] burned for approximately two minutes. Articles in late 1944 claimed that the flame was so hot it could crumble a brick wall. And for propaganda purposes the RAF dubbed the new incendiary bomb the Superflamer.[11] Around fifty-five million incendiary bombs were dropped on Germany by Avro Lancasters alone.


Post World War II incendiary weaponsEdit

Modern incendiary bombs usually contain thermite, made from aluminium and ferric oxide. It takes very high temperatures to ignite, but when alight, it can burn through solid steel. In World War II, such devices were employed in incendiary grenades to burn through heavy armour plate, or as a quick welding mechanism to destroy artillery and other complex machined weapons.

A variety of pyrophoric materials can also be used: selected organometallic compounds, most often triethylaluminium, trimethylaluminium, and some other alkyl and aryl derivatives of aluminium, magnesium, boron, zinc, sodium, and lithium, can be used. Thickened triethylaluminium, a napalm-like substance that ignites in contact with air, is known as thickened pyrophoric agent, or TPA.

Napalm was widely used by the United States during the Korean War,[12] most notably during the battle "Outpost Harry" in South Korea during the night of June 10–11, 1953.[citation needed] Eighth Army chemical officer Donald Bode reported that on an "average good day" UN pilots used 70,000 gallons of napalm, with approximately 60,000 gallons of this thrown by US forces.[13] Winston Churchill, among others, criticized American use of napalm in Korea, calling it "very cruel", as the US/UN forces, he said, were "splashing it all over the civilian population", "tortur[ing] great masses of people". The American official who took this statement declined to publicize it.[14]

During the Vietnam War, the U.S. Air Force developed the CBU-55, a cluster bomb incendiary fuelled by propane, a weapon that was used only once in warfare.[15] Napalm however, became an intrinsic element of U.S. military action during the Vietnam War as forces made increasing use of it for its tactical and psychological effects. Reportedly about 388,000 tons of U.S. napalm bombs were dropped in the region between 1963 and 1973, compared to 32,357 tons used over three years in the Korean War, and 16,500 tons dropped on Japan in 1945.[16][17]

Napalm proper is no longer used by the United States, although the kerosene-fuelled Mark 77 MOD 5 Firebomb is currently in use. The United States has confirmed the use of Mark 77s in Operation Iraqi Freedom in 2003.

Incendiary weapons and laws of warfareEdit

Signatory states are bound by Protocol III of the UN Convention on Conventional Weapons which governs the use of incendiary weapons:


Protocol III states though that incendiary weapons do not include:

  • Munitions designed to combine penetration, blast or fragmentation effects with an additional incendiary effect, such as armor-piercing projectiles, fragmentation shells, explosive bombs and similar combined-effects munitions in which the incendiary effect is not specifically designed to cause burn injury to persons, but to be used against military objectives, such as armoured vehicles, aircraft and installations or facilities.

See alsoEdit


  3. ^ Hanson, pp. 413–414
  4. ^ Hanson, pp. 437–438
  5. ^ Dye, Peter (2009). "ROYAL AIR FORCE HISTORICAL SOCIETY JOURNAL 45 – RFC BOMBS & BOMBING 1912–1918 (pp. 12–13)" (PDF). Royal Air Force Historical Society. Retrieved 1 May 2014.
  6. ^ Hanson, p. 412
  7. ^ World War II Guide. Archived 30 August 2005 at the Wayback Machine
  8. ^ "How we fight Japan with fire". Popular Science. May 1945. Retrieved 9 December 2015.
  9. ^ "German Ordnance". The Doric Columns. Retrieved 1 May 2014.
  10. ^ a b Hussey, G.F., Jr. (4 January 1970) [6 October 1946]. "British English Ordnance" (PDF). Command Naval Ordnance Systems. Archived from the original (PDF) on 4 March 2016. Retrieved 8 December 2015.
  12. ^ Pike, John. "Napalm".
  13. ^ Neer, Robert (2013). Napalm: An American Biography. Harvard University Press. p. 99.
  14. ^ Neer, Robert M. (2013). Napalm: An American Biography. Harvard University Press. pp. 102–3.
  16. ^ "Books in brief. Napalm: An American Biography Robert M. Neer Harvard University Press 352 pp". Nature. 496 (7443): 29. 2013. doi:10.1038/496029a.
  17. ^ "Liquid Fire – How Napalm Was Used In The Vietnam War". Nikola Budanovic. Retrieved 8 November 2017.

External linksEdit