During the war, 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.

In 1940, when the German invasion of Great 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.

76 or Special Incendiary Phosphorus grenade, which consisted of a glass bottle filled with a mixture similar to Fenian fire, plus some latex.

These were improvised anti-tank weapons, hastily fielded in 1940 when the British were awaiting a potential German invasion after losing the bulk of their modern armaments in the Dunkirk evacuation.

[citation needed] At the start of the Normandy campaign, 20% of American 81 mm mortar ammunition consisted of M57 point-detonating bursting smoke rounds using WP filler.

White phosphorus was widely used by Allied soldiers for breaking up German attacks and creating havoc among enemy troop concentrations during the latter part of the war.

White phosphorus grenades were used by the US in Vietnam to destroy Viet Cong tunnel complexes as they would burn up all oxygen and suffocate the enemy soldiers sheltering inside.

"[12] The March/April 2005 issue of an official Army publication called Field Artillery Magazine reported that "White phosphorus proved to be an effective and versatile munition and a potent psychological weapon against the insurgents in trench lines and spider holes. ...

[15] On 15 November 2005, following denials to the press from the US ambassadors in London and Rome, the US Department of Defense confirmed that US forces had used white phosphorus as an incendiary weapon in Fallujah, in order to drive combatants out of dug-in positions.

"[18] Professor Paul Rodgers from the University of Bradford department of peace and conflict studies said that white phosphorus would probably fall into the category of chemical weapons if it was used directly against people.

[21] Amnesty International and Human Rights Watch accused Israel of using white phosphorous artillery shells indiscriminately in its attack in Dhayra, Lebanon on October 16, that injured at least nine civilians, and that it was unlawful.

[25] According to a confidential report prepared by the government of one of United Nations Interim Force in Lebanon's contributing countries that was reviewed by the Financial Times, on 13 October multiple white phosphorus munitions were fired within 100 metres of a UNIFIL base, injuring 15 peacekeepers, after an incident where Israeli Merkava tanks had broken into the base and stayed for 45 minutes.

[26] In its early statements regarding the Gaza War of 2008–2009, the Israeli military denied using WP entirely, saying "The IDF acts only in accordance with what is permitted by international law and does not use white phosphorus.

[36] The Israeli government report further stated that smoke screening projectiles were the majority of the munitions containing white phosphorus employed by the IDF and that these were very effective in that role.

[37] The Goldstone report accepted that white phosphorus is not illegal under international law but did find that the Israelis were "systematically reckless in determining its use in built-up areas".

On detonation of the bursting charge, the canister deploys 116 units 19 millimetres (0.75 in), quarter-circle wedges of felt impregnated with 5.8 kilograms (12.75 lb) of WP, producing a smokescreen lasting 5–10 minutes depending on weather conditions.

During the Second Nagorno-Karabakh War, on 31 October 2020 the Ministry of Defence of the unrecognised Republic of Artsakh stated that the Azerbaijani side had used phosphorus weapons to burn forests near Shusha (Shushi).

[53][54][55] On 20 November, the Prosecutor General's Office of Azerbaijan filed a lawsuit, accusing the Armenian Armed Forces of using phosphorus ammunition in Nagorno-Karabakh, as well as in Tartar District.

[57][58][59][60] Non-governmental international organizations have recorded the military use of white phosphorus in Syria, Afghanistan, the Gaza Strip, and other war zones.

[68]Weight-for-weight, phosphorus is the most effective smoke-screening agent known,[69] for two reasons: first, it absorbs most of the screening mass from the surrounding atmosphere and secondly, the smoke particles are actually an aerosol, a mist of liquid droplets which are close to the ideal range of sizes for Mie scattering of visible light.

In practice, the droplets quickly reach a range of sizes suitable for scattering visible light and then start to dissipate from wind or convection.

Other approaches include WP soaked felt pads (which also burn more slowly, and pose a reduced risk of incendiarism) and PWP, or plasticised white phosphorus.

The white phosphorus granules, big about as grains of sand, are coated with GR-S (Government Rubber-Styrene) rubber, gelled with xylene.

The resulting rubbery mass does not atomize so readily, gets broken up to several millimeters sized pieces, and burns for several minutes, reducing the pillaring.

[80] In some cases, injury is limited to areas of exposed skin because the smaller WP particles do not burn completely through personal clothing before being consumed.

Due to the pyrophoric nature of WP, penetrating injuries are immediately treated by smothering the wound using water, damp cloth or mud, isolating it from oxygen until fragments can be removed: military forces will typically do so using a bayonet or knife where able.

Bicarbonate solution is applied to the wound to neutralise any build-up of phosphoric acid, followed by removal of any remaining visible fragments: these are easily observed as they are luminescent in dark surroundings.

Surgical debridement around the wound is used to avoid fragments too small to detect causing later systemic failure, with further treatment proceeding as with a thermal burn.

The US Agency for Toxic Substances and Disease Registry has set an acute inhalation Minimum Risk Level (MRL) for white phosphorus smoke of 0.02 mg/m3, the same as fuel-oil fumes.

[81] The agency cautioned that studies used to determine the MRL were based on extrapolations from animal testing and may not accurately reflect the health risk to humans.