As a teen I put 1/2 pound of 5 year "old" GOEX 3Fg in an aluminum potato chip bag, twisted it shut, rammed a long fuse down the middle and set it in a bowl shaped depression of fresh green pasture grass.
I lit the fuse and started to run. I got about 3 steps when there was a loud Whoosh! and I felt what was like an instant sunburn all over my back under my white t- shirt.
I spun around to see a perfect mushroom cloud 10 to 15 feet high and still rising. The aluminum bag was vaporized, all grass was gone and the bare ground was seared black. My 6 y.o. brother standing 50 yards away said "Boy, that was close" and I learned
blackpowder never gets "Old" if its dry.