LarryD:
I use FastBond, "methylene chloride" (causes cancer in California but, used to decafinate coffee every where else).
I wouldn't be a bit surprised to find that California has "may cause cancer" labels on bottles of water.
Regarding OP's question - have you tried to use, instead of ferric chloride, a different etchant? Something like:
Now - ultimately, such etchant will become "toxic" - in that it will contain a ton of copper in solution; but there are ways to recover the copper and dispose of it properly. In other words, while "cleaner" than ferric chloride, you still don't want to just "dump it down the sink".
I've also heard that such etchants aren't as quick or such as FC - but it might be something to play around with, as you might be able to make a container that can't resist it better than FC...