My guess is that it is due to some chemical in the munitions or projectile propellants that were used. Some have suggested it is from the depleted uranium used in a lot of the armor piercing munitions. It is not necessarily a radiation thing, either, uranium has chemical properties too which are not very well understood. It is a heavy metal that is bioactive.

Think of a tank being hit by a burst of armor piercing cannon fire, the bullets pierce the armor, shatter and explode, pulverizing into dust and gas as the vehicle bursts into flame, its own ordnance cooks off and explodes, fuel, lubricants, plastics and paint burn and react chemically with each other. GIs breathe in the fumes and climb all over these blasted vehicles gathering intelligence, souvenirs, or just getting their pictures taken.

It might have been some kind of Iraqi chemical warfare agent, it might not have been effective as a weapon, but had unexpected long-term secondary effects that didn't show up right away. Or mayby it was the smoke from all those oil well fires reacting synergistically with something else. It could be from one of the many smoke and pyrotechnic devices armies use to mark landing zones or targets or friendly positions. And of course, missiles and rockets often use some pretty exotic chemicals as propellants and warhead explosives. The modern battlefield must be a toxic hazmat zone.

Has it occurred to anyone to check to see if Iraqi soldiers in the battle zone experienced the same symptoms our guys did?