To break down the analysis by Paul Reynolds
World Affairs correspondent, BBC News ......
ref as above

WP - THE ARGUMENTS

So WP itself is not a chemical weapon and therefore not illegal. However, used in a certain way, it might become one. Not that "a certain way" can easily be defined, if at all.

The US can say therefore that this is not a chemical weapon and further, it argues that it is not the toxic properties but the heat from WP which causes the damage. And, this argument goes, since incendiary weapons are not covered by the CWC, therefore the use of WP against combatants is not prohibited.

Critics claim that the US used chemical weapons in Falluja, on the grounds that it is the toxic properties which cause the harm. The UK's Guardian newspaper for example said: "The US used chemical weapons in Iraq - and then lied about it."

There is an intense debate on the blog sites about this issue. "It's not a chemical weapon" says Liberal Against Terror. "CONFIRMED: WP is a CW if used to cause harm through toxic properties," says Daily Kos.

Update 22 November: I have received an e-mail from a reader who points me to a reported US army document from 1991** which refers to WP as a chemical weapon. The document reports the possible use of WP by Iraq against the Kurds who rose up after the Gulf War. It says: "Iraq has possibly employed phosphorous chemical weapons against the Kurdish population."

The reader said this was proof that the US viewed WP as a CW.

I have also been contacted by Gabriele Zamparini of the Cat's Dream blog who appears to have published this document first. He makes the same point that the US Defense Department itself called WP a "chemical weapon." I offer these comments as part of the debate "

** the document I quoted from in a previous post


TACTICAL USE OF WP

The other argument is about the use of WP as a weapon.

The initial denials from the Pentagon suggest a certain hesitation, embarrassment even, about such a tactic. Some decisions must have been taken in the past to limit its use in certain battlefield scenarios (urban warfare for example). It is not used against civilians.

However the United States has not signed up to a convention covering incendiary weapons which seeks to restrict their use.

This convention has the cumbersome title "Convention on Certain Conventional Weapons." Agreed in 1980, its Protocol III covers "Prohibitions or Restrictions on use of Incendiary Weapons."

This prohibits WP or other incendiaries (like flamethrowers) against civilians or civilian objects and its use by air strikes against military targets located in a concentration of civilians. It also limits WP use by other means (such as mortars or direct fire from tanks) against military targets in a civilian area. Such targets have to be separated from civilian concentrations and "all feasible precautions" taken to avoid civilian casualties.

Notwithstanding the US position on the Convention, the use of WP against insurgents within Falluja does at least bring the issue into discussion, though one should note that the soldiers who wrote the Field Artillery article do say that their unit "encountered few civilians in its attack south".