Are you saying there’s evidence that DU is toxic, or that it is the primary cause of incidents of congenital heart failure in Fallujah?
In the first case I completely agree DU is absolutely toxic. If a tank were lit up by a DU penetrator I absolutely would not want to breathe the smoke. But I would not want to breathe the smoke from a burning tank and I don’t really care how it was knocked out. The smoke is going to be a toxic mess regardless. By the way the alternative is Tungsten which is 1) also somewhat toxic and 2) often alloyed with Thorium which is also radioactive.
With regards to Fallujah, one problem I have with this theory is that DU is used in Armor Piercing rounds (specifically armour-piercing fin-stabilized discarding sabots or APFSDS). The most important thing to understand about Fallujah is that the insurgents did not have armored vehicles in that battle and it would have made no sense to use APFSDS against soft targets. For instance it’d go right through a pickup truck and leave a tiny hole. The discarded fins would do more damage than the penetrator. Note I’m not arguing that Fallujah wasn’t left a toxic mess by the Americans. There’s millions of rounds of lead m4 ammo for instance. To say nothing about the residue of nalpam and white phosphorus.
By the way one of the main ingredients of nalpalm is Benzene or, as my chemist friend said “Benzene is what anti-nuclear people think nuclear waste is”