The one-gallon can of gas for your lawn mower sitting in the garage is MANY ORDERS OF MAGNITUDE MORE DANGEROUS than dozens of 8# smokeless powder caddies stored nearby. Smokeless powder in commercial packaging is only slightly more dangerous than dirt. The only exception to this is large quantities of smokeless powder--55 gallon barrels or similar storage--in which it compresses by weight and can ignite and sustain compressed combustion and build to destructive levels. (My background includes State of California and NFPA certification as a fire cause & origin investigator).
Now, black powder.......different story. Scary, squirrelly stuff. In all storage/containment modes, it is a low-order explosive. It is easily ignited and largely uncontrollable once combustion commences. No containment is required to propagate its explosive character.