Most substances are not "explosive" unless they are ignited in some confined space. If someone saw the powder then it was not confined.We're dealing with muzzies here, not rational human beings. Maybe some Imam TOLD him the powder would magically explode.
My guess is that we're dealing with know-nothing reporters. Suggesting that someone trying to ignite some exposed powder was lighting an explosive is enough to call for close examination of the entire story.
ML/NJ