Why is white phosphorous so dangerous?
White phosphorus is hazardous in many ways. For example:

- White phosphorus is spontaneously combustible and burns rapidly upon exposure to air, as it ignites in air at approximately 86°F (30°C).
- The fumes, or phosphorus oxides, produced by burning phosphorus are toxic, which can cause severe irritation and the sensation of a foreign body in the eye.
- White phosphorus is extremely toxic to humans, with a lethal dose of 1mg per kg of body weight when  ingested orally.
- White phosphorus is highly fat soluble, which means it can be easily absorbed through the skin, possibly causing whole-body effects.
Does the use of white phosphorous munition on a battlefield constitutes as a war crime?
The use of white phosphorus as a weapon is a controversial issue and its legality is subject to interpretation. The use of incendiary weapons, including white phosphorus, is banned by the Protocol III of the Convention on Certain Conventional Weapons (CCW). However, the protocol permits the use of incendiary weapons for certain purposes, such as to create smoke screens, mark targets, or as a signaling device.

The use of white phosphorus in densely populated areas, such as cities or civilian areas, could result in significant harm to civilians and civilian objects, which may violate the principles of distinction, proportionality, and precaution under international humanitarian law. Therefore, the use of white phosphorus in a manner that causes excessive harm to civilians may be considered a war crime under the international law of armed conflict.

However, the legality of the use of white phosphorus in specific circumstances can be complex and subject to interpretation. Ultimately, the legality of the use of white phosphorus as a weapon depends on the specific facts and circumstances of each case.