Black powder is inherently dangerous if mishandled, and great care must be taken to store and handle it in such a way as to avoid static electricity of all kinds, as well as all other sources of sparks or flames.
One thing that sets it apart from modern propellant powders is that it will flash in the open, i.e. if flame or spark is applied to a quantity of black powder lying in the open, it will burn POOF! with a flash, and be done. When it burns, black powder produces a sulphurous odor, leaves corrosive residue in a gun's barrel, and produces a thick white smoke.
Modern "smokeless" powder, on the other hand, generally burns rather than flashing when it's not contained, and as a rule produces little or no smoke. Modern powders are non-corrosive, produce less fouling, and produce a much less pronounced odor than black powder.
