Incendiary device

Loading aMark 77napalm bomb onto aUS MarineStrike Fighter SquadronF/A-18A Hornet aircraftduring a June 1993 training exercise

A 17th century fire or light ball fromVeste Coburg,Germany

Incendiary weapons,incendiary devices,incendiary munitions,orincendiary bombsare weapons designed to start fires. They may destroy structures or sensitive equipment using fire, and sometimes operate asanti-personnel weaponry.Incendiaries utilize materials such asnapalm,thermite,magnesium powder,chlorine trifluoride,orwhite phosphorus.Though colloquially often called "bombs",they are notexplosivesbut in fact operate to slow the process of chemical reactions and useignitionrather thandetonationto start 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 history

Main article:Early thermal weapons

A range of early thermal weapons were utilized byancient,medieval/post-classicalandearly modernarmies, including hotpitch,oil,resin,animal fat and other similar compounds. Substances such asquicklimeandsulfurcould be toxic and blinding. Incendiary mixtures, such as the petroleum-basedGreek fire,were launched by throwing machines or administered through asiphon.Sulfur- and oil-soaked materials were sometimes ignited and thrown at the enemy, or attached to spears, arrows orbolts,and fired by hand or machine. Some siege techniques—such asminingand boring—relied on combustibles and fire to complete the collapse of walls and structures.

Towards the latter part of the period,gunpowderwas invented, which increased the sophistication of the weapons, starting withfire lances.

Development and use in World War I

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

The first incendiary devices to be dropped during World War I fell on coastal towns in the east of England on the night of 18–19 January 1915. The small number of German bombs, also known as firebombs, were finned containers filled withkeroseneand oil and wrapped with tar-covered rope. They were dropped fromZeppelinairships.On 8 September 1915, Zeppelin L-13 dropped a large number of firebombs, but even then the results were poor and they were generally ineffective in terms of the damage inflicted. They did have a considerable effect on the morale of the civilian population of the United Kingdom.

After further experiments with 5-litre barrels ofbenzol,in 1918, the B-1EElektronfire bomb (German:Elektronbrandbombe) was developed by scientists and engineers at theGriesheim-Elektron chemical works. The bomb was ignited by athermitecharge, but the main incendiary effect was from themagnesiumand aluminium alloy casing, which ignited at 650 °C, burned at 1,100 °C and emitted vapour that burned at 1,800 °C. A further advantage of the alloy casing was its lightness, being a quarter of the density of steel, which meant that each bomber could carry a considerable number.TheGerman High Commanddevised an operation called "The Fire Plan" (German:Der Feuerplan), which involved the use of the whole German heavy bomber fleet, flying in waves over London and Paris and dropping all the incendiary bombs that they could carry, until they were either all shot down or the crews were too exhausted to fly. The hope was that the two capitals would be engulfed in an inextinguishable blaze, causing the Allies to sue for peace.Thousands of Elektron bombs were stockpiled at forward bomber bases and the operation was scheduled for August and again in early September 1918, but on both occasions, the order to take off was countermanded at the last moment, perhaps because of the fear of Allied reprisals against German cities.TheRoyal Air Forcehad already used their own "Baby" Incendiary Bomb (BIB) which also contained a thermite charge.A plan to fire bomb New York with new long range Zeppelins of the L70 class was proposed by the naval airship fleet commanderPeter Strasserin July 1918, but it was vetoed by AdmiralReinhard Scheer.

Development and use in World War II

A GermanWorld War II1 kg incendiary bomb

Incendiary bombs were used extensively inWorld War IIas an effective bombing weapon, often in a conjunction with high-explosive bombs.Probably the most famous incendiary attacks are thebombing of Dresdenand thebombing of Tokyo on 10 March 1945.Many different configurations of incendiary bombs and a wide range of filling materials such as isobutyl methacrylate (IM) polymer,napalm,and similar jellied-petroleum formulas were used, many of them developed by the USChemical Warfare Service.Different methods of delivery, e.g. small bombs, bomblet clusters and large bombs, were tested and implemented.For example, a large bomb casing was filled with small sticks of incendiary (bomblets); the casing was designed to open at altitude, scattering the bomblets in order to cover a wide area. An explosive charge would then ignite the incendiary material, often starting a raging fire. The fire would burn at extreme temperatures that could destroy most buildings made of wood or other combustible materials (buildings constructed of stone tend to resist incendiary destruction unless they are first blown open by high explosives).

Burning ballroom at theRoyal Castle, Warsaw,as a result of incendiary bombing by the GermanLuftwaffe

The GermanLuftwaffestarted the war using the 1918-designed one-kilogram magnesium alloy B-1EElektronbrandbombe;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 singleHe 111bomber could carry 1,152 incendiary bombs, or more usually a mixed load. Less successful was theFlammenbombe,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.

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.Nazi Germanybegan the campaign ofincendiary bombingsat the start of World War II with thebombing of Warsaw,and continued with theLondon Blitzand the bombing of Moscow, among other cities. Later, an extensivereprisalwas enacted by theAlliesin thestrategic bombing campaignthat led to the near-annihilation of many German cities. In thePacific War,during the last seven months of strategic bombing byB-29 Superfortressesinthe air war against Japan,a change to firebombing tactics resulted in the death of 500,000 Japanese and the homelessness of five million more. Sixty-seven Japanese cities lost significant areas to incendiary attacks. The most deadly single bombing raid in history wasOperation Meetinghouse,an incendiary attack that killed some 100,000 Tokyo residents in one night.

BritishI.B. 4-lb. Mk IVtype incendiary bomb. Top: complete device, nose is red. Middle: dud found without the tin plate tail. Bottom: the remains after burning.RAF Bomber Commanddropped 80 million 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 byICI,was the standard light incendiary bomb used byRAF Bomber Commandin 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 theBritish "dehousing" plan.The bomb consisted of a hollow body made from aluminium-magnesiumalloywith a cast iron/steel nose, and filled withthermiteincendiary 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 Lancasterbomb bay showing later mix of4,000-pound "Cookie" blast bomband 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, theIncendiary Bomb, 30-lb., Type J, Mk I,burned for approximately two minutes. Articles in late 1944 claimed that the flame was so hot it could crumble a brick wall. For propaganda purposes the RAF dubbed the new incendiary bomb theSuperflamer. Around fifty-five million incendiary bombs were dropped on Germany byAvro Lancastersalone.

Many incendiary weapons developed and deployed during World War II were in the form of bombs and shells whose main incendiary component iswhite phosphorus(WP), and can be used in an offensive anti-personnel role against enemy troop concentrations, but WP is also used for signalling,smoke screens,and target-marking purposes. The U.S. Army and Marines used WP extensively in World War II andKoreafor all three purposes, frequently using WP shells in large 4.2-inch chemical mortars. WP was widely credited by many Allied soldiers for breaking up numerous German infantry attacks and creating havoc among enemy troop concentrations during the latter part of World War II. In both World War II and Korea, WP was found particularly useful in overcoming enemyhuman wave attacks.

Incendiary weapons after World War II

Napalm was widely used by the United States during theKorean War,most notably during the battle "Outpost Harry"in South Korea during the night of June 10–11, 1953.Eighth Army chemical officer Donald Bode reported that on an "average good day" UN pilots used 70,000 US gallons (260,000 L) of napalm, with approximately 60,000 US gallons (230,000 L) of this thrown by US forces.British Prime MinisterWinston Churchillprivately criticized the use of napalm in Korea, writing that it was "very cruel", as US/UN forces, he wrote, were "splashing it all over the civilian population", "tortur[ing] great masses of people". He conveyed these sentiments to U.S.Chairman of the Joint Chiefs of StaffOmar Bradley,who "never published the statement". Publicly, Churchill allowed Bradley "to issue a statement that confirmed U.K. support for U.S. napalm attacks".

During theVietnam War,theU.S. Air Forcedeveloped theCBU-55,acluster bombincendiary fuelled bypropane,a weapon that was used only once in warfare.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.

Incendiary bombs used in the late 20th century sometimes containedthermite,made from aluminium andferric 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 heavyarmourplate, or as a quickweldingmechanism to destroyartilleryand other complex machined weapons.

A variety ofpyrophoricmaterials can also be used: selectedorganometalliccompounds, most oftentriethylaluminium,trimethylaluminium,and some otheralkylandarylderivatives of aluminium,magnesium,boron,zinc,sodium,andlithium,can be used. Thickened triethylaluminium, a napalm-like substance that ignites in contact with air, is known asthickened pyrophoric agent,or TPA.

Napalm proper is no longer used by the United States, although thekerosene-fuelledMark 77 MOD 5 Firebombis currently in use. The United States has confirmed the use of Mark 77s inOperation Iraqi Freedomin 2003.

Incendiary weapons and laws of warfare

Signatory states are bound by Protocol III of theUN Convention on Conventional Weaponswhich governs the use of incendiary weapons:

• prohibits the use of incendiary weapons against civilians (effectively a reaffirmation of the general prohibition on attacks against civilians inAdditional Protocol Ito theGeneva Conventions)
• prohibits the use of air-delivered incendiary weapons againstmilitary targetslocated within concentrations of civilians and loosely regulates the use of other types of incendiary weapons in such circumstances.

Protocol III states though that incendiary weapons do not include:

• Munitions which may have incidental incendiary effects, such as illuminates,tracers,smoke or signaling systems;
• 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 also

• Arson
• Bat bomb
• Driptorch
• Early thermal weapons
• Fire accelerant
• Fire balloon
• Firestorm
• Fire bombing
• Flame fougasse
• Flamethrower
• Greek fire(Historic Byzantine incendiary weapon)
• High explosive incendiary(HEI)
• Incendiary ammunition
• Meng Huo You(Historic Chinese incendiary weapon)
• Molotov cocktail
• Napalm
• Pen Huo Qi(Historic Chinese flamethrower)
• Stinkpot(Historic Chinese incendiary weapon)

External links

• Protocol III to the Convention on Prohibitions or Restrictions on the Use of Certain Conventional Weapons which may be deemed to be Excessively Injurious or to have Indiscriminate Effects
• United States Strategic Bombing Survey (Pacific War) 1946
• Fire From The Sky1944 article on the production of incendiary bombs
• AN-M50-series incendiary bombsArchived9 April 2015 at theWayback Machine(German)