I store it on the shelf of a cabinet above my loading table. All my powders are in the same cabinet,along with points,dies,empty boxes,and loading manuals. Primers are in a file cabinet next to the bench. Which also has drawers full of loaded ammo. I store all powders in original containers.
I live in a rural area served by a volunteer fire dept. They have a do not fight order on my workshop,which means they will not enter or vent the building but will stand back and pour water on it.