Storage and Shipment
- "White phosphorus (P4) is the elemental form of phosphorus used in smoke munitions. It has a high vapor pressure and will readily sublimate when exposed to air. At room temperature, autoignition will occur and the material will burn violently. In the absence of air, P4 is quite stable. White phosphorus is normally stored under water for this reason. Cool, saturated soils with no open pore spaces are also very effective in preventing the sublimation and ignition of P4." 
- "Explosive Safety Quantity Distance (ESQD) requirements apply to the concentration of ammunition, explosives, and other hazardous materials at Naval Shore Establishments for development; manufacturing; test and maintenance; storage, loading and off-loading of vehicles, railcars and aircraft; disposal; and all related handling incidents. ... Group H, one of twelve travel and storage categories for ammunition and explosives, includes "explosives and white phosphorus or other pyrophoric material, ... Ammunition in this group contains filler, which is spontaneously flammable when exposed to the atmosphere. Examples of these items are white phosphorus (WP), white phosphorus plasticized (PWP), or other ammunition containing pyrophoric material." Group H materials may only be stored or shipped with Group S materials, which are those which present "no significant hazard." 
White Phosphorus Not Banned
"[U]se of white phosphorus is not specifically banned by any treaty, however protocol III of the 1980 Geneva convention prohibits the use of incendiary weapons against civilian populations or by air attack against military forces that are located within concentrations of civilians. The United States is among the nations that have not signed this protocol." 
A warehouse fire which began on June 6, 2005, and burned for 17 hours, at the Pine Bluff Arsenal, Arkansas, "the Army's sole supplier of white phosphorus ammunition in the Western Hemisphere," was believed by investigators to have been "triggered by a leaking container of white phosphorus. ... The blaze destroyed a warehouse that held more than 7,500 containers of white phosphorus, which is used in incendiary devices and in smoke screenings and signals for 155 millimeter shells." 
White Phosphorus at War
"White phosphorus is both a smoke producer and a particularly nasty incendiary agent, known as WP. Its white smoke has the highest total obscuring power (TOP) of any smoke. It was widely used in World War I in grenades and trench mortar rounds to screen troop movements. Most military smokes are now of other types, often colored with dyes. The 4.2-in. 'Chemical' mortar of World War II was developed to throw white phosphorus shells, as well as whatever other chemical or biological agents might be required, but was later also found valuable as a general heavy mortar. This was a simple, light, portable weapon of great power, equivalent to a 105 mm howitzer, but of lesser range. It consisted of a tube about 5 ft long, a steel baseplate, and a bipod support with screws for elevation and traverse. The cylindrical round was simply dropped down the tube, and it sailed away on a high trajectory. The phosphorus sticks to whatever it hits, burns, and if what it has hit is combustible, sets it on fire. White phosphorus burns quickly and cooly and so is not a very effective incendiary agent. It is generally mixed with rubber or polystyrene to slow down the burning. Water will put out white phosphorus temporarily, but as soon as the phosphorus has access to air, it will start burning again. White phosphorus wounds are very unpleasant, since the phosphorus must be thoroughly washed out with a nonpolar solvent that is also noninflammable, for obvious reasons, before the burn can be treated. Carbon tetrachloride would be suitable, but it is dangerous because of the cancer hazard." --Dr. James B. Calvert, University of Denver, last revised March 6, 2004. (emphasis added)
During the Vietnam War, the "White Phosphorus (WP), M110, was also used as a marker round. It could be fitted with PD, VT, and MT fuzes. When the situation called for it, white phosphorus became a devastating weapon against personnel. The thick white smoke could be used as a screen to mask movement by troops in the field." --1/92 Field Artillery Association - Vietnam. (emphasis added)
White Phosphorus "Climate" in Iraq
Average temperatures in Iraq range from more than 120°F (48°C) in July and August "to below freezing in January. ... Roughly 90% of the annual rainfall occurs between November and April, most of it in the winter months from December through March. The remaining six months, particularly the hottest ones of June, July, and August, at approximately 102°F (32°C), are dry." 
The autoignition temperature for white phosphorus is 93°F (34°C). 
"It is commonly believed that white phosphorus ignites spontaneously on contact with air at room temperature. This is not quite true; the autoignition temperature is actually about 30°C in humid air, and slightly higher in dry air. ... At any rate, the slightest degree of friction will easily ignite it, and it is practically guaranteed to be ignited by a burster charge, so for all intents and purposes it is pyrophoric," according to the Wikipedia.
"As an incendiary, it is most effective against highly flammable targets like very dry vegetation or petrol, oils and lubricants. However a WP fire does have the special difficulty that if extinguished with water, even to the point of being quite cold, it may reignite later when it dries out and exposes the WP to the air again."
"Burns to persons struck by particles of burning WP are usually much less extensive than napalm or metal incendiary burns, but are complicated by the toxicity of phosphorus, the release of phosphoric acid into the wounds, and the possibility of small particles continuing to smoulder for some time if undetected," the Wikipedia informs.
- Jason E. Levy, "TTPs for the 60mm mortar section," Infantry Magazine, May-June 2004.
- "U.S. Army publication confirms United States used incendiary weapon in Falluja," The Raw Story, November 10, 2005.
Unexploded Ordnance (UXO)
- Rockets: "The warhead section of the rocket is the portion that produces the intended effect; it can be filled with explosives, toxic chemicals, white phosphorus, submunitions, riot-control agent, or illumination flares." --US Army Corps of Engineers.
- Mortars: "Mortars range from approximately 1 inch to 11 inches in diameter and can be filled with explosives, toxic chemicals, white phosphorus, or illumination flares. Mortars generally have thinner metal casing than projectiles, but use the same types of fuzing and stabilization." --US Army Corps of Engineers.
- 49CFR173.59. Chapter I: Research and Special Programs Administration, Department of Transportation, U.S. Government Printing Office, Revised as of October 1, 2002 (pp. 450-456). Part 73: Shippers. General Requirements for Shipments and Packagings. Definitions, Classification and Packaging for Class 1.
- "About Unexploded Ordnance," U.S. Army, Jefferson Proving Ground.
- "US Army Battle Book -- System and Weapon Data" US Army Command and General Staff College.
- Seth Ackerman, "Now It’s a Chemical Weapon, Now It’s Not: White Phosphorus and the Siege of Fallujah", Extra!, March/April 2006.
- "Israel admits phosphorus bombing," BBC, October 22, 2006.