Isn't most pressure treated lumber done so witharsenic? Given that your rabbits will invariably chew the wood, theywill be ingesting certain amunts of this chemical. Also, did you everget a splinter from PT lumber? It hurts a heck of a lot more thanuntreated wood. This is due to the chemicals, I would guess. Itcertainly isn't worth the risk building a cage out this material.
I am assuming your are referring to PT lumber - if not, my comments may not be valid.
Sean