Rules for barrels of explosives?

[danzibr]

I'm interested in how 3.5 treats lighting a big barrel of, well, something like gunpowder on fire.

The closest thing I found were the ditherbombs in RotD, but that's not the same at all. Any ideas?

[lycantrope]

DMG has rules for gunpowder in the alternate worlds section where they give stats for guns/muskets.

[danzibr]

Found it! Or something close enough. Explosive Pack, Secrets of Sarlona, p. 138.