White phosphorus (WP) is a material made from a common allotrope of the chemical element phosphorus that is used in smoke, tracer, illumination and incendiary munitions.
As an incendiary weapon, WP burns fiercely and can set cloth, fuel, ammunition and other combustibles on fire. Since WWII, it has been extensively used as an anti-personnel weapon capable of causing serious burns or death. The agent is used in bombs, artillery, and mortars, short-range missiles which burst into burning flakes of phosphorus upon impact. White phosphorus is commonly referred to in military jargon as "WP", and the slang term "Willy/Willie Pete/Peter" (dating from World War I) is still commonly used by infantry and artillery servicemen.
WP is also a highly efficient smoke producing agent, burning quickly and causing an instant bank of smoke. As a result, smoke producing WP munitions are very common, particularly as smoke grenades for infantry, loaded in defensive grenade dischargers on tanks and other armored vehicles, or as part of the ammunition allotment for artillery or mortars. These create smokescreens to mask movement from the enemy, or to mask his fire.
WP is believed to have been first used by Fenian arsonists in the 19th century in the form of a solution of WP in carbon disulfide. When the carbon disulfide evaporated, the WP would burst into flames, and probably also ignite the highly flammable carbon disulfide fumes. This mixture was known as "Fenian fire" and allegedly was used by disgruntled itinerant workers in Australia to cause delayed destruction of shabby sleeping quarters.
In 1916, during an intense ideological struggle over conscription for the First World War, twelve members of the I.W.W., a radical union of workers who openly opposed conscription, were arrested and convicted for using or plotting to use incendiary materials, including phosphorus. It is believed that eight or nine men in this group, known as the Sydney Twelve, had been framed by the police. Most were released in 1920 after an inquiry.
The British Army introduced the first factory-built WP grenades in late 1916. In World War II, white phosphorus mortar bombs, shells, rockets and grenades were used extensively by American, Commonwealth, and to a lesser extent Japanese forces, in both smoke-generating and antipersonnel roles. The British used White phosphorus bombs against Kurdish villagers and Al-Habbaniyah in Al-Anbar province during the Great Iraqi Revolution of 1920.
In 1940, when the invasion of Britain seemed imminent, the phosphorus firm of Albright and Wilson suggested that the British government use a material similar to Fenian fire in several expedient incendiary weapons. The only one fielded was the Grenade, No. 76 or Special Incendiary Phosphorus grenade, which consisted of a glass bottle filled with a mixture similar to Fenian fire, plus some latex (cf. Molotov cocktail, Greek fire). It came in two versions, one with a red cap intended to be thrown by hand, and a slightly stronger bottle with a green cap, intended to be launched from the Northover projector (a crude 2.5 inch blackpowder grenade launcher). These were improvised anti-tank weapons, hastily fielded in 1940 when the British were awaiting a German invasion after losing the bulk of their modern armaments in France in May 1940.
At the start of the Normandy campaign, 20% of American 81 mm mortar rounds were WP. At least five American Medal of Honor citations mention their recipients using white phosphorus grenades to clear enemy positions. In the 1944 liberation of Cherbourg alone, a single U.S. mortar battalion, the 87th, fired 11,899 white phosphorus rounds into the city.
The U.S. Army and Marines used WP shells in 107-mm [4.2 Inch] mortars. WP was widely credited by Allied soldiers for breaking up German infantry attacks and creating havoc among enemy troop concentrations during the latter part of the war. American servicemen in the Pacific and otherwise (to this day) were known to call the thrown bottles "Willie Pete" grenades. The origin of the term has been thought to be derived from the British military's phonetic alphabet.
Incendiary bombs were used extensively by the German, British and US air forces against civilian populations and targets of military significance in civilian areas (London, Hamburg, Dresden, Area bombing etc). Late in the war, some of these bombs used white phosphorus (about 1-200 grams) in place of magnesium as the igniter for their flammable mixtures. The use of incendiary weapons against civilians was banned (by signatory countries) in the 1980 Convention on Certain Conventional Weapons Protocol III. The USA signed Protocols I and II on March 24, 1995 (and the amended article II on May 24, 1999) and later Protocols III, IV, and V, on January 21, 2009.
WP munitions were used extensively in Korea, Vietnam and later by Russian forces in Chechnya. According to GlobalSecurity.org, during the December 1994 battle for Grozny in Chechnya, every fourth or fifth Russian artillery or mortar round fired was a smoke or white phosphorus round.
In Iraq, the Saddam Hussein regime used white phosphorus, as well as chemical weapons that are scheduled in the Chemical Weapons Convention, in the Halabja poison gas attack during the Iran–Iraq War in 1988, according to the ANSA news agency.
Another news report said "US intelligence" called WP a chemical weapon in a declassified Pentagon report from February 1991:
"Iraqi forces loyal to President Saddam may have possibly used white phosphorus chemical weapons against Kurdish rebels and the populace in Erbil and Dohuk. The WP chemical was delivered by artillery rounds and helicopter gunships."
but the actual declassified document contains the words "WARNING: (U) THIS IS AN INFORMATION REPORT, NOT FINALLY EVALUATED INTELLIGENCE." By "information report", the document states it is not a reviewed product of the intelligence community. Further, the document's addressee codes all start with the letter R, which means that they are in the military operational community, not the Y-community that is reserved for the intelligence community (Chapter IV, Section 11).
Use WP against in Iraq (2004)
Use WP against in Israel-Lebanon conflict (2006)
Use WP against in Gaza War (2008-2009)
Use WP against in Afghanistan (2009)
Use WP against in Use in Yemen (2009)