This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on phosphorus, elemental, white or yellow. "White phosphorus is a colorless, white, or yellow waxy solid with a garlic-like odor. It does not occur naturally, but is manufactured from phosphate rocks. White phosphorus reacts rapidly with oxygen, easily catching fire at temperatures 10 to 15 degrees above room temperature. White phosphorus is used by the military in various types of ammunition, and to produce smoke for concealing troop movements and identifying targets. It is also used by industry to produce phosphoric acid and other chemicals for use in fertilizers, food additives, and cleaning compounds. Small amounts of white phosphorus were used in the past in pesticides and fireworks."
Centers for Disease Control and Prevention: http://www.cdc.gov/