I'm not worried about it, Trust me there is alot of stuff in that garage that scares the hell out of me... If it scares me, it would make most people wet thier pants.
I've talked with a bunch of chemists about this, and what can be done about it.
Oddly enough, not one of them has given me a legal solution. every thing from pore it down the drain to dig a hole. One guy even said heat it up to about 275F so it will burn. The one I like the most was to get a large orgainc fliter( aka actvated charcoal) and off gas it thru that. Then dig a hole.