BBC NEWS | Middle East | US used white phosphorus in Iraq
White phosphorus is highly flammable and ignites on contact with oxygen. If the substance hits someone's body, it will burn until deprived of oxygen.
Globalsecurity.org, a defence website, says: "Phosphorus burns on the skin are deep and painful... These weapons are particularly nasty because white phosphorus continues to burn until it disappears... it could burn right down to the bone."
'I treated people who had their skin melted'
"They used these weird bombs that put up smoke like a mushroom cloud," he said. He had seen "pieces of these bombs explode into large fires that continued to burn on the skin even after people dumped water on the burns".