I'll stop you there Davek.
ALL explosives are toxic (especially nitro ones). They're also persistent in the environment - so called PBT and vPvB (persistent bioaccumulative and toxic and very Polluting very Bioaccumulative).
ALL explosives give off residues of the explosives (that don't explode)
There are still World War I and World War II residues in French fields, getting rid of them is something called
bioremidiation.
Also the western nations have recognised this fact and even provide research towards better less toxic alternatives
"Environmentally friendly" explosives get ready for ignition" - New Scientist
Making a safer bang for the buck - Los Alamos Research Team Identifies Replacements for Mercury and Lead in Primary Explosives
Environmentally friendly explosives, Chemical Science Journal - Royal Society of Chemistry
Now.... I take huge issue with that BBC story.
Its directly blaming the americans, however I'd blame the militants for using PBT explosives in their "Improvised Explosive Devices" using home made explosives!
Its just another case of trying to make anti-Western propaganda.
Equally, the bias in the story is incredible: given:
Fallujah was heavily industrialised during the Saddam era, with the construction of several large factories, including one closed down by United Nations Special Commission (UNSCOM) in the 1990s that may have been used to create chemical weapons. A new highway system (a part of Saddam's infrastructure initiatives) circumvented Fallujah and gradually caused the city to decline in national importance by the time of the Iraq War
So investigations should take place, because I suspect (infact know first hand) - the easy option of pointing fingers at the americans might show something interesting and set the record straight!