See, here's the problem -- anything that expands really quickly from a small amount and is sealed in a burst-able container is an explosive. It might not be a registered pyrotechnic, but the hazard is still there. Search these boards, people are always looking for insight, and we're limited in what we can say, for legal reasons. I came up with a simple, non-pyrotechnic "bang" and it got erased by a Mod: