White Phosphorus: The Controversial Weapon Under Scrutiny Amid the Escalating US-Israel-Iran War

As tensions rise in the ongoing war involving Israel, Iran and the United States, fresh allegations about the use of white phosphorus munitions have drawn international attention. Rights groups say the Israeli military recently fired the substance over residential areas in southern Lebanon, raising serious humanitarian and legal concerns.

The Israeli military did not immediately respond to requests for comment. In the past, however, it has maintained that white phosphorus is used primarily to create smoke screens on the battlefield rather than to target civilians.

Human rights organisations argue that when deployed in populated areas, the weapon can have devastating consequences. Reports from advocacy groups say the chemical can ignite buildings, cause severe burns and leave survivors vulnerable to life-threatening complications.

What is white phosphorus?

White phosphorus is a pale yellow, wax-like chemical substance that ignites immediately when exposed to oxygen. Once lit, it burns at extremely high temperatures and produces thick white smoke.

Because of these properties, militaries have used it for decades for several battlefield purposes. These include creating smoke screens to conceal troop movements, illuminating areas at night, marking targets and destroying military equipment or fuel supplies.

The substance has been used in warfare since the World War II and continues to be part of many countries’ arsenals today.

In artillery form, white phosphorus can be packed into shells that burst mid-air. When this happens, dozens of burning fragments scatter over a wide area. In open battlefields, this may be intended to create a large smoke curtain, but in residential areas the fragments can land on homes, streets and people.

Why is it so dangerous?

White phosphorus causes some of the most severe burn injuries seen in conflict zones.

When burning fragments come in contact with skin, they continue to burn as long as oxygen is present. This means the chemical can penetrate deep into tissue and burn through muscle and bone. Even after being extinguished, the substance can reignite if it comes in contact with air again.

Medical experts say treating such burns is extremely difficult.

The danger does not stop at direct contact. As white phosphorus burns, it releases toxic fumes that can severely damage the respiratory system if inhaled. Exposure to the smoke may cause lung injury, chemical pneumonia and long-term breathing problems.

In some cases, if the chemical enters the bloodstream through a burn wound, it can damage internal organs such as the liver, kidneys and heart, potentially leading to organ failure.

Another major risk is fire. The burning fragments can easily ignite buildings, vegetation and other materials, making fires difficult to control once they start.

Is white phosphorus banned?

Despite its destructive effects, white phosphorus is not completely banned under international law.

It is not classified as a chemical weapon under the Chemical Weapons Convention because the primary harm it causes comes from heat and flames rather than toxic chemical reactions.

Instead, its use is regulated by the Convention on Certain Conventional Weapons (CCW), specifically Protocol III, which governs incendiary weapons.

The treaty does not prohibit white phosphorus outright, but it places restrictions on how incendiary weapons can be used. For instance, air-delivered incendiary weapons cannot be used against military targets located within civilian areas and armed forces must take precautions to minimise harm to civilians.

Human rights groups argue that the problem lies not in the existence of the weapon but in how it is deployed.

If white phosphorus is used in a way that scatters burning fragments over densely populated areas, it can violate fundamental principles of international humanitarian law, including the rules of distinction, proportionality and precaution.

Why the latest allegations matter?

Advocacy groups say the alleged use of white phosphorus in southern Lebanon mirrors earlier accusations made during past confrontations between Israel and the Iran-backed militant group Hezbollah.

Organisations such as Human Rights Watch and Amnesty International have previously documented similar incidents in southern Lebanon and in Gaza Strip during earlier phases of the conflict.

“The Israeli military’s unlawful use of white phosphorus over residential areas is extremely alarming and will have dire consequences for civilians,” said Ramzi Kaiss, Lebanon researcher at Human Rights Watch.

Human rights advocates say the weapon becomes particularly dangerous when used over populated areas, where burning fragments can fall indiscriminately across homes, streets and civilian infrastructure.

As the war involving the United States, Israel and Iran continues to escalate, the allegations have once again sparked a global debate about the legality and humanitarian consequences of white phosphorus in modern warfare.

While the weapon itself remains legal under international treaties, experts say its use in densely populated areas could still amount to an unlawful attack if it fails to distinguish between military targets and civilians.

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