Thanks Bob, for that detailed declaration. You certainly have captured my attention.
A couple of years ago, one of our local lumber mills exploded and many people were seriously hurt. The explosion was caused be fine particles of wood dust floating in the air, and some kind of spark. But in a mill where electric motors the size of VW's are running 24 hours a day, a spark wouldn't be hard to find. And I know that flour, when it is powdered to dust and suspends in the air, can be explosive as well, from static electricity.
And yet, the powder companies ship and store their products in plastic containers, including BP and smokeless. I just bought two pounds of IMR 4198 in plastic bottles. And almost all of my store of Black Powder, GOEX, Schutzen, and Swiss, is in plastic containers. I've been loading black powder into the plastic powder containers of my various reloading presses for years, without incident. But the percentage of 'fines' in the powder is very very small, and thus far, has posed no issues.
When I pour powder from a plastic 'can' into a powder horn, there always appears a small cloud of very fine dust which I blow away from the action...I have sometimes wondered if that cloud of dust is dangerous.
As far as generating a static spark with moccasins on a concrete driveway, that's a new one on me. Years ago, we had a pair of Siamese cats that loved being dragged back and forth by their feet across a thick wool carpet, until a two inch long blue static spark appeared at the end of their tail. then, when released, they would richochet around the house for a minute and come straight back, flop down on the carpet, and want to go again. Crazy cats.
The best I can say now, is that this issue with black powder and static is unresolved....