I agree with Buffalo, If your prospective tenants are already complaining,
it sounds like it might be more of a headache then its worth. I too would
release them from the lease citing medical concerns. Then relist the rental
property, you don't know how the house was built, you can only assume it was
done correctly in regard to vapor barriers, ETC;.. The house my wife and I
just bought looked great at the time we looked at it, it looked great when
we did our walk through and even our inpsector said the problems he found
were only minor. Well, things happen, our furnace died, a whole electrical
circuit is not correct and the garage was a mess with errant electrical
wiring. Seems the guy that had the house before ran wires whereever the hell
he wanted without regard. You will never know all the problems a house poses
prior to buying it, you have to live with it before it lets out all its
secrets. Then you have to hope you have the knowledge to do the repairs or
have the money to have them done.

Searcher