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Tuesday, January 27, 2009

All you wanted to know about white phosphorus (guest post)

Two weeks ago, commenters Bill and Bill #2 wrote quite a bit about white phosphorus, and I wanted to post it so it would get a larger audience (as well as come up in Google searches for years to come...)
[Bill]: White phosphorus is *not* a chemical weapon. It is an incendiary. The 'WMD' nonsense is the revival of an old leftist slander against US forces in Iraq.

[Bill #2]: There are two types of white phosphorus (WP) smoke shells, one bursting and one with base ejection of smoke producing material. The bursting shells produce an immediate white smoke screen through the sudden oxidation of phosphorus in air. The base ejection shells emit larger discrete phosphorus-soaked felt that disperses and allows the phosphorus to oxidise more slowly. The ones that Israel are accused of using (so far) is the base ejection shells that are really only useful in producing smoke screens and not so useful for their incendiary effect. They are also safer in their usual deployment since the phosphorus is embedded in a carrier, making it far easier to treat incidental burn injuries.

You can tell the difference between the two:
Bursting smoke has a omnidirectional spherical burst with a large number of larger burning fragments of phosphorus extending beyond the white cloud. They are normally detonated at ground level, since the smoke cloud will approximate a hemisphere sitting on the ground, and in addition the heat of oxidation makes the resultant cloud qickly rise in a column of smoke and thus be less effective at ground level.

Base ejection smoke has a small burst where the smoke-producing fragments are emitted and spray out in a limited cone to the ground. This munition has its best effect when deployed in air burst to achieve a wider dispersion of its discrete smoke producing elements. The characteristic cone or fan of smoke producing elements in the air is quite photogenic, so there are numerous pictures of this.

Neither are Chemical Weapons, as banned by the Geneva Convention 1925. Most nationalities in WW2 and later deployed white phosphorus bursting smoke shells, and nobody was brought to trial for use of these as 'Chemical Weapons' at Nuremberg.

Neither are Incendary Weapons, as defined by Geneva Convention Protocol III(1980), Article 1: "(b) Incendiary weapons do not include:
(i) Munitions which may have incidental incendiary effects, such as illuminants, tracers, smoke or signalling systems; ", so the restrictions on their use in Article 2 is not applicable.

[Bill]:If could butt into your excellent post, I should point out that some of the confusion stems from WP's dual uses as a pyrotechnic and as an incendiary, and to the confusion (often deliberately used by anti-mil types) regarding applicable Int'l Law.

Pyrotechnics (smoke, marking, tracers, flares etc) are not restricted at all, and are specifically exempted both by the Chemical Weapons Convention (CWC) and Convention on Certain Conventional Weapons (CCCW).

The CWC, just as Geneva III did, specifically excludes from the definition of 'chemical agents' weapons that operate by thermal effect (heat)- i.e. incendiaries.

The CCCW's main body forbids the use of incendiary weapons against civilians (who are already immune to attack under Geneva IV)- but not against combatant forces. Burn 'em up.

Protocol III (1977) to the CCCW additionally prohibits the use of incendiaries against combatants when they are amidst or in proximity to civilian populations: but neither Israel nor the US is a signatory to Protocol III.

[Bill #2, responding to a question]: The white bursts with the fan of smoke trails [that are visible in photographs] are base ejection white phosphorus.

Hamas has found discarded shells verifying their use, but are of course incorrectly claiming a war crime in their deployment: http://www.timesonline.co.uk/ tol...icle5519433.ece You can look up the empty munition they triumphantly display at Janes: http://www.janes.com/extracts/ex...h/ jah_0461.html

I would not want to be in the area when one went off, but that is mainly because you will have a heavy empty shell casing falling to the ground after it has ejected its smoke producing contents, and it's got to land somewhere. If you were at ground level underneath the deployment of the felt wedges, you would be almost certainly safe if you were in a car or under some non-flammable overhead shelter. The residue from the burning phosphorous is poisonous, but then again many of the residues from military explosives are similarly poisonous too. The burning phosphorus oxidises to phosphorus dioxide, and scavenges the water vapour in the air to form the smoke you can see in the pictures. This is the reason that it is used - the smoke shell does not have to contain all the material that provides the obscuration, but enlists the water vapour in the air to assist in that process. You would want to avoid breathing the smoke, but the smoke screen is passable by friendly troops without requiring the use of gas masks, so you shouldn't consider this a gas chemical weapon. The phosphorus pentoxide is transformed by the water then into phosphoric acid, the same chemical found in fizzy cola drinks and rust remover. The low concentration of phosphorus in the smoke is unlikely to be dangerous to those exposed for short periods.

Should a burning piece of phosphorus-soaked felt from the smoke shell come in contact with clothing or skin, you would first treat it as for any other burn - the first aid is for dousing with water and removal of remaining burning pieces. With proper deployment, the base ejection smoke shell is safer, since it is unlikely that phosphorus fragments are driven into a body as might be the case with impact bursting white phosphorus shells.

[EoZ]:Do you have any idea of what kind of phosphorus payload was shot by Hamas at Israel in a Qassam yesterday, and where they could have gotten it from?

[captainfish]: I liked in the article the evidence cited as evidence of Israeli use of chemical weapons was that people's feet were burned when they walked in the area that was under one of these bursts.

Seems rather odd that the burned residue from an air burst would still be "burnable" after laying on the ground after a while. And, why would you walk on the ground with bare feet in an area that is under attack?

[Bill #2]: In the Second World War, 20% of the mortar munition supplied to American troops in Normandy was bursting white phosphorus (WP) munitions http://www.nationmaster.com/ency...phorus-(weapon) . All major participants in this war used it. Since then, it has remained in use, basically because it is so effective for rapid smoke screens.

EOZ, it is most likely that the phosphorus load for the Qassam came from an intact 81mm WP mortar bomb. Just a small sample of the many countries that make bursting WP mortar bombs are China, Iran, Turkey, Austria, Russia, and the USA. Since the white phosphorus contents are self igniting, it is not a material that lends itself to home manufacture or scavenging and reuse of existing WP munition's contents. Some countries make Red Phosphorus base-ejecting mortar bombs, which could be used but are nowhere near as useful as a payload for a Qassam which necessarily has to use an impact fuse. As a military munition, a Qassam WP warhead provides no military purpose either for illumination nor concealment purposes, and thus its unguided firing at civilian areas probably does contradict the laws of warfare against firing at protected persons, as it does if its payload was all explosives. The good news is that it is probably not a 120mm mortar bomb, which would weigh about 12-13kg, probably more than a Qassam is capable of carrying the distances they want, and so their payload is likely to be poorly matched with the rocket engine.

With regard to the Israeli smoke ammunition, base-ejection shells that eject a fan of phosphorus-saturated felt-wedges, if you deprive the phosphorus oxygen, such as dousing them with water, sand, or soil, they remain ready to re-ignite after oxygen can again reach the phosphorus. I speculate that the wedges of felt are engineered to not form an oxygen-restrictive ash crust around the felt which would otherwise reduce their effectiveness as smoke producers. There is no military reason for having some the phosphorus left unoxidised and a potential hazard - it is an unwanted side effect.

An old party trick was to ... [exact description redacted by me, Bill #2, for safety's sake on consideration]... and light it when it was sitting on a large coin. When you rubbed the residue left on the coin between your fingers, smoke came off your fingers [Do Not Try This At Home]. Essentially it was a mini scale distillation of the red phosphorus, turning it into yellow and red phosphorus sublimating on the cooler metal object. White, yellow and red phosphorus are all phosphorus, but differ in the way the atoms are arranged in the solid (they are called allotropes of Phosphorus). Each allotrope of Phosphorus has markedly different reactivities, with red phosphorus being the least reactive.

This is what is possibly happening on the ground, captfish. When the felt wedges are burning on the ground, some of the white phosphorus is evaporated, but due to the inadequate oxygen doesn't burn but condenses on any nearby object that is below that of its boiling point, as white, yellow and red allotropes. As oxygen becomes available, the white phosphorus will burn, but the other allotropes may only oxidise slowly. Over time, some of that yellow phosphorus will catch fire, but some may have enough red phosphorus in it to be stable enough to not burn. Someone comes along with bare feet, steps on an oxygen-deprived felt wedge, or on a residue of condensed red and yellow phosphorus and the oxidation process accelerates with consequent heat. As I can personally witness, even skin friction can make the mix of allotropes burn.

The proportionally huge number of poorly supervised, by western standards, young people in the civilian population means that there is a huge pool of curious boys who will investigate anything that seems to relate to the events happening around them. I suspect that many of these boys are not being educated to be wary of military munitions, especially those articles which seem to be a 'dud' and apparently inert, or even those which are believed to be expended. They also may gain this nonchalance from poor weapons and munition handling by their elders. Wandering around in a battleground in bare feet is an extremely bad idea, for more than one reason.

Note that the interspersal of active Hamas fighters and civilians has made separation of the curious from dangerous objects, buildings and places impossible. This is a war crime by Hamas, and by these actions Israel is permitted to fight Hamas in such areas as their protected nature has already been compromised by Hamas. The rules of war were drafted to make the attempted use of human shields by one side useless since they would not be protected by international law, and thus be dissuaded from trying. Various commentators seem to be misinterpreting these laws of war, accidently or deliberately. The laws of warfare were developed to reduce the consequential damage to civilians, and to allow Hamas to be shielded by these laws is to increase the civilian deaths and suffering that will result in the long term.

I reject the claim: "Two wrongs don't make a right!", as it is perfectly clear that the deliberate placement of military personnel and munitions in otherwise protected places dissolves their protected place status. Thus under international law, there is only one wrong being committed here, not two.

I reject the claim: "The laws of war disallow the use of white phosphorous under all circumstances." People might feel it is morally wrong, but it is not a war crime.

I reject the misguided belief that the Principle of Proportionality means that you can only fight an enemy with only an equivalent force, and must stop if your enemy is taking more casualties than you are.

I reject the notion that Hamas shouldn't be held to the same moral standards that Israel is held to.