[Geoffrey]

I seriously doubt it was black gunpowder.

Smokeless powder yes. Pyrodex or equivalent maybe.

There are probably local fire department codes or state laws that are tougher than federal levels. Varies a lot by jurisdiction, and can be very difficult to find an answer to.

[Geoffrey]

There are probably local fire department codes or local laws that are tougher than state and federal levels. Varies a lot by jurisdiction, and can be very difficult to find an answer to.

I corrected my answer.

[thackney]

I seriously doubt it was black gunpowder.

I take it you didn't look at the pictures in the article I linked.

http://goexpowder.com/goex-black-powder.html