One of my mentors has been shooting and reloading for more than 60 years and he swears by keeping bp in a unplugged refridgerator , he's never had a problem with it .For years I kept mine in the room that I do my reloading and I noticed that in the summer the powder got pretty warm , that room gets hot enough to melt a candle on a shelf . Recently I built a new gun room outside of my house and put all of my powder in a spare fridge (not running) and everytime I've checked it it's always room temperature between 70 to 80 degrees even when it's 107 like it was outside today .This room is insulated also I'm so satisfied with this that I put several boxes of reloads in the frifge along with all of my primers .I don't expect to have any problems with fire in this new gun room but if I do at least it's not in my house any more