sloughfoot
Grandmaster
Another vote for a spare bedroom in the house, or some space inside. Sometimes I kind of wonder about having all those explosives in the house in case of fire, but frankly they probably wouldn't do any better in the garage either. (Fantasy time)... it would be nice to have a separate "Workshop" building, with heat, air, water and electricity to do all my reloading in, but then my wife would probably get mad that I spent too much time in the workshop, and not enough in the house.
I don't know of any "explosives" that are used in the manufacture or re-manufacture of small arms ammunition.
Or are you loading artillery shells?