Is there a way we can get out of our Lease/Purchase Agreement?

We are buying our house with a lease to purchase agreement. It states if we do not exercise our right to purchase we forfeit all deposits and money we have put down. The lease also states the house is being sold "as is". My son has been hospitalized multiple times for severe asthma reactions and it has been brought to our attention that we have a major mold issue in our basement behind the drywall. Is there any way we will be able to get out of this agreement and get our money back since this is a severe health hazard that was covered up instead of addressed and we had no way of knowing since the basement was already finished when we were shown the house? We really don't want to lose everything we have put forward but we can't jepordize our children's heath either. Please help!