I would ask them to provide proof of ownership and the document that you signed stating that you understood that the underground tank was theirs. Chances are they can't locate any documentation.
I am not sure how it works out with the purchase of a house but I would suspect that there has to be some documentation as to property that is on the property that is not part of the land and house purchase.
I am not sure how it works out with the purchase of a house but I would suspect that there has to be some documentation as to property that is on the property that is not part of the land and house purchase.