Weapons Law Encyclopedia

White phosphorus munitions

Phosphorus was discovered by Henning Brandt, an alchemist from Hamburg, in 1669. White phosphorus has been used since World War I both as an incendiary agent and for creating smoke screens or smoke signals. Munitions containing white phosphorus were used extensively in World War II , the Vietnam War, and the Korea War, including as an anti-personnel weapon.ICRC, Weapons that may Cause Unnecessary Suffering or have Indiscriminate Effects, Experts Report, Geneva, 1973, §188.

Instances of recent use include the following:

  • According to a classified US Department of Defense document former Iraqi ‘President Saddam (Hussein) may have possibly used white phosphorous (WP) chemical weapons against Kurdish rebels and the populace in Erbil’ in February 1991.Possible Use of Phosphorous Chemical’, Department of Defense, Doc. No. IIR 2 243 1050 91.
  • WP munitions were reportedly used by Russian forces in Grozny (1994-1995). According to Grau, ‘every fourth or fifth Russian artillery or mortar round fired was a smoke or white phosphorus round’.L. W. Grau, ‘Changing Russian Urban Tactics: The Aftermath Of The Battle For Grozny’, (article first published in INSS Strategic Forum, no. 38, July 1995).
  • In 2004, US forces used artillery shells loaded with WP in Fallujah, Iraq, to target insurgents in so-called ‘shake and bake’ fire missions. US representatives initially denied having used white phosphorus as a weapon, but later a US Department of Defense spokesman reportedly told BBC News that the US used WP as ‘an incendiary weapon against enemy combatants’ during its 2005 attack on Fallujah, Iraq.'US Used White Phosphorous in Iraq’, BBC News, 16 November, 2005. See also, A. Buncombe and S. Hughes, ‘The Fog of War: White Phosphorus, Fallujah and Some Burning Questions’, The Independent (UK), 15 November 2005.
  • Israeli forces used weapons containing white phosphorus in Lebanon in 2006, and in Gaza in 2008/2009. M. Rappaport, ‘Israel admits using phosphorus bombs during war in Lebanon’, Haaretz, 22 October 2006; UN doc. A/HRC/3/2, 23 November 2006, §§ 258–62; UN doc. S/2009/537, §§ 9, 207, and 488. ‘One of the most widely reported incidents during the Gaza Operation involved the UNRWA field office compound, where three individuals were injured and significant property damage resulted from the use of smoke-screen munitions containing white phosphorous.’ (Second follow-up to the report of the United Nations Fact-Finding Mission on the Gaza Conflict, Report of the Secretary-General, UN doc. A/64/890,11 August 2010, §92.)
  • Mortar shells containing white phosphorus have allegedly also been fired from Gaza into Israeli territory on several occasions. UN doc. S/2012/5, 6 January 2012; S/2010/590, 2 December 2010.
  • During a battle at Shalan Sharaf, in the Shirkole area of Mogadishu on 13 April 2007, Ethiopian military forces used WP bombs against the Shabaab. As a result, approximately 15 Shabaab fighters and 35 civilians were killed.Letter dated 17 July 2007 from the Chairman of the Security Council Committee established pursuant to resolution 751 (1992) concerning Somalia addressed to the President of the Security Council, UN doc. S/2007/436, 18 July 2007, §§30-34.
  • U.S. and other international forces in Afghanistan have reportedly used WP munitions. Human Rights Watch documented an incident on 14 March 2009, in which an 8-year-old girl in Kapisa province was burned by white phosphorus munitions. Tensions Flare as G.I.’s Take Fire Out of Pakistan’, The New York Times, 16 October 2011; Human Rights Watch, ‘Afghanistan: NATO Should “Come Clean” on White Phosphorus’, 8 May 2009. See also, S. Goose and B. Docherty, ‘White phosphorous: the new napalm?’, Salon, 8 June 2012.
  • The US, in turn, have accused Afghan militants of using WP as a weapon in attacks on US forces and in civilian areas.J. Straziuso, ‘Afghan Taliban Suspected Of Using White Phosphorous Illegally’, The Huffington Post, 5 November 2009.
  • Weapons containing WP have reportedly also been used in Syria in 2012-2013.N. R. Jenzen-Jones, ‘Likely Evidence of White Phosphorus Use in Syria’, The Rogue Adventurer, 17 December 2012.
  • Myanmar police forces ‘deployed military-issue white phosphorus incendiary smoke grenades’ to disperse monks and farmers assembled in peaceful protest against a controversial copper mining project in Letpadaung hills on 29 November 2012. The government initially denied that incendiary devices had been used by the police but an official Investigation Commission concluded that ‘108 people including 99 monks had been injured in the incident and 55 smoke bombs containing phosphorus had been used in the police raid. The report [of the Commission] found that the smoke bombs, although not deployed as incendiaries can react with flammable materials or cause fires when used in high numbers.[footnote omitted] The Report recommended that authorities receive training on riot-control techniques and faulted the police for not understanding how to properly deploy the smoke bombs.’ The Commission’s report has been severely criticised by human rights organizations as inaccurate and inadequate in its conclusions and recommendations.The Commission’s report was published in Burmese only on 12 March 2013.See, ‘Letpadaung Investigation Commission Issues Final Report’, Myanmar Law, Charltons, Issue no. 3, 19 April 2013; Report of the Special Rapporteur on the situation of human rights in Myanmar, Tomás Ojea Quintana, UN doc. A/HRC/22/58, 22 March 2013, §30; Lawyers Network and Justice Trust, Report of Evidence Regarding Controversies at Letpadaung Hill Copper Mine Project, 14 February 2013; Asian Legal Resource Centre (ALRC), ‘MYANMAR: Police Who Attacked Peaceful Protestors Must Be Prosecuted’, 22 May 2013; Asian Human Rights Commission, ‘BURMA: Two sharply contrasting reports on the struggle for land at Letpadaung’, 3 April 2013.

Last updated on: 04 August 2017

WP has a variety of civilian and military applications. Weapons containing WP can be used for different purposes, including for signalling, screening, illuminating and to kill, injure or cause damage through fire and heat. 

WP weapons can take many different forms and be delivered in various ways, including as artillery or mortar shells, air-dropped bombs, rockets, projectiles for tank guns or howitzers or as hand- or rifle grenades, and fitted with different fuses (e.g. air-burst or point-detonating).

Unitary WP projectiles, such as the US-made M110A1 155mm shell, ‘contain a solid mass of WP and a central bursting charge. They are typically employed with a point detonating fuze, which functions upon contact with the target. The fuze detonates the central burster, dispersing the WP filler.N. R. Jenzen-Jones, ‘Likely Evidence of White Phosphorus Use in Syria’, The Rogue Adventurer, 17 December 2012.

The M825A1 155mm artillery projectile (used for instance by Israeli Defence Forces in Gaza in 2008/2009) ‘is designed to produce a dispersed smokescreen by ejecting 116 ¾ inch felt wedges impregnated with WP over the target location. These wedges ignite upon contact with the air, and fall to the ground burning. The twisting trails left by this process have earned the projectile the nickname of “Medusa” in some artillery circles.’ (http://rogueadventurer.com/2012/12/13/differential-identification-of-white-phosphorus-and-zab-submunitions-in-syria/) According to Human Rights Watch, air bursting such a white phosphorus artillery shells ‘spreads 116 burning wafers over an area between 125 and 250 meters in diameter, depending on the altitude of the burst, thereby exposing more civilians and civilian infrastructure to potential harm than a localized ground burst.’Human Rights Watch, 'Israel: Stop Unlawful Use of White Phosphorus in Gaza', 10 January 2009.

Last updated on: 04 August 2017

White phosphorus (chemical formula: P4; also known as ‘Willy Pete’ in military jargon) is a chemical substance that is white to yellow translucent, wax-like and has a pungent, garlic-like, acrid odor.

White phosphorus ignites spontaneously upon exposure to air (it is pyrophoric) at a temperature of around 30-34 degrees Celsius (or lower) by reaction with oxygen, forming ‘phosphorus pentoxide’ (P4O10). This chemical process (oxidation) releases intense heat, produces a bright light and dense white smoke.The smoke is produced due to the reaction of phosphorus pentoxide with moisture in the air. In the reaction of phosphorus pentoxide with water (in the air or in the human body) phosphoric acid (H3PO4) is formed.

WP continues to burn until oxygen supply is cut off or the substance is depleted.

WP is used in particular by the military to create smoke screens to shield troops and assets from the enemy. The smoke is impenetrable to infrared optics, making it especially effective for protecting tanks from guided missiles.Human Rights Watch and Harvard Law School International Human Rights Clinic, 'The Need to Re-Visit Protocol III on Incendiary Weapons', Memorandum to CCW Delegates, November 2010.

WP weapons are also used for illumination, marking and signalling. Although WP is not an effective incendiary substance for use against structures that are difficult to ignite, it has been used as an incendiary weapon against persons and to ignite oil-based incendiaries, ammunition caches and to detonate mines. MacLeod and Rogers believe that WP use is on the increase in 21st century warfare. They also identify a ‘trend towards anti-personnel use’ of WP. One such application is the use of WP munitions in so-called ‘bake and shake’ missions to ‘smoke out’ or ‘flush out’ enemy combatants from hiding places, causing them to flee the smoke and fire by going outside where they can be attacked with explosive weapons.‘There seems little doubt that WP was used for anti-personnel purposes in the battle of Fallujah.’(I. J. MacLeod and A. P. V. Rogers, ‘The Use of White Phosphorus and the Law of War’, 10(2007) Yearbook of International Humanitarian Law, 78). See also, R. Reyhani, ‘The Legality of the Use of White Phosphorus by the United States Military During the 2004 Fallujah Assaults’, 10(2007) Journal of Law and Social Change, 4.


Regardless of intended purpose, weapons containing WP can have severe negative impacts on human health.‘The most problematic incendiary weapons today are those containing white phosphorus.’ (Human Rights Watch and Harvard Law School International Human Rights Clinic, 'Q & A on Incendiary Weapons and CCW Protocol III', November 2011)

WP causes severe, partial to full-thickness thermal and chemical burns upon contact with skin, often down to the bone. ‘Usually the phosphorus is scattered in small adhesive lumps, which result in a great number of fairly small but deep burns. If the burning phosphorus particles remain unextinguished, muscles and other deep tissues may be damaged, resulting in permanent loss of motor function.' WP can also cause damage by absorbing water from surrounding tissues.ICRC, Weapons that may Cause UnnecessarySuffering or have Indiscriminate Effects, Experts Report, Geneva, 1973, §218.  For more information on burn injuries from incendiary weapons, see Report of the Secretary-General, ‘Napalm and Other Incendiary Weapons and all Aspects of their Possible Use’, UN doc. A/8803/Rev. 1, 1973 and SIPRI, Incendiary Weapons, 1975.

WP is extremely toxic when inhaled, ingested, or absorbed through burned areas. WP is also highly soluble in fat, and thus in human flesh. Absorbed through the skin WP can survive long enough in the human body to damage the heart, kidney or liver, leading to multiple organ failure or death. ‘There is no antidote for white phosphorus toxicity’.M. Frank et al., ‘Not all that glistens is gold: civilian white phosphorus burn injuries’, 26(8)(2008) The American Journal of Emergency Medicine, 974.e3-974.e5; 'White Phosphorus: Systemic Agent', Centres for Disease Control and Prevention, last updated 18 June 2013.

Burns from WP are slow to heal and likely to develop infections. Local destruction of tissues continues as long as white phosphorus is exposed to oxygen. Tissues deep under the skin may be impregnated by metal and phosphorous fragments. The severe injuries caused by white phosphorus are intensely painful and require immediate, specialized, and intensive medical care, which can be difficult to provide in situations of armed conflict. Due to the danger of systemic effects, any metal fragments that are covered with liquid WP, as well as any embedded pieces of WP must be excised.R. F. Bellamy et al., 'The Weapons of Conventional Land Warfare', in R. F. Bellamy and R. Zajtchuk et al. (eds.), Conventional Warfare: Ballistic, Blast and Burn Injuries, Office of the Surgeon General, Department of the Army,  Walter Reed Army Institute of Research, Walter Reed Army Medical Center, 1991,  48-9. According to Hashey, ‘traditional methods of dressing burns can make phosphorus burns worse’.P. Hashey, 'White Phosphorous Munitions: International Controversy in Modern Military Conflict', 17 (2011) New England Journal of International and Comparative Law, 291. Owing to these systemic effects, burns over only a small surface of the body are often fatal.Human Rights Watch and Harvard Law School International Human Rights Clinic, 'The Human Suffering Caused by Incendiary Munitions', Memorandum to Convention on Conventional Weapons Delegates, March 2011; SIPRI, Incendiary Weapons, 1975, 198 and Appendix 4A. MacLeod and Rogers note at p. 89 that WP burns result in a vastly increased mortality rate compared to non-phosphorus burns (I. J. MacLeod and A. P. V. Rogers, ‘The Use of White Phosphorus and the Law of War’, 10(2007) Yearbook of International Humanitarian Law). In 'Detailed Facts about White Phosphorus', the US Army Centre for Health Promotion and Preventive Medicine describes WP as an ‘extremely toxic’ substance.

Because white phosphorus can reignite upon drying, WP in wounds that have been cleaned and dressed can start to burn again when dressings are removed, causing further injury. Victims and medical professionals are also at risk of inadvertently spreading the substance and suffering burns, in particular on the hands.

The smoke produced by WP weapons is 'irritating and toxic' and can cause injury to the eyes and the respiratory tract.

Material damage

Weapons containing white phosphorus, whether used for incendiary or other purposes, can set objects on fire, causing damage to private property and public infrastructure. The spread of such fires is difficult to predict and control. (See the entry on incendiary weapons)

One well-documented incident involves damage to the UNRWA compound from WP weapons used by Israeli Defence Forces:

On January 15, at least three IDF white phosphorus shells struck the main compound of the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) in central Gaza City, wounding three people and starting fires that gutted four buildings and destroyed more than US$3.7 million worth of medical supplies.

Environmental and societal impacts

Exposed to air, WP can continue to burn for several days after its dispersal and pose a continuing threat of injury to civilians and to ERW clearance personnel. Human Rights Watch (Rain of Fire, 2009) documents cases of civilians who were injured as a result of stepping on white phosphorus remains up to 12 days after major hostilities had ended.

Munitions containing white phosphorus may also generate toxic remnants of war (TRW), raising concerns about longer-term health and environmental impacts. One recent pilot-study on the incidence of major structural birth defects at Gaza’s Al Shifa Hospital found that parents’ exposure to white phosphorus in the 2008/2009 military attacks correlates significantly with the occurrence of birth defects in children.A. Naim et al., ‘Birth Defects in Gaza: Prevalence, Types, Familiarity and Correlation with Environmental Factors’, 9(5)2012 International Journal of Environmental Research and Public Health, 1732-1747.

WP is 'very toxic to aquatic life with long lasting effects'. In water with low oxygen, WP may degrade to a highly toxic compound called phosphine. It can build up in the bodies of fish that live in contaminated lakes or streams. One source cautions that 'Runoff from fire control may be corrosive, toxic and cause pollution'.See also, 'White Phosphorus', Agency for Toxic Substances and Disease Registry ToxFAQs, U.S. Department of Health and Human Services, September 1997.

Last updated on: 04 August 2017

Applicable international, regional & national law

1980 Protocol on Incendiary Weapons

The 1980 Protocol III on Incendiary Weapons of the Convention on Certain Conventional Weapons restricts use of incendiary weapons as a means or method of warfare during armed conflict.

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1992 Chemical Weapons Convention

The 1992 Chemical Weapons Convention prohibits the development, production, stockpiling, transfer and use of chemical weapons and requires States Parties to destroy chemical weapon stockpiles.

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