Marketing Lead w/ Oil Tank Contamination

I have a lead from a marketing campaign that apparently has an underground oil tank (or possibly even two!) and there was apparently "some leaking". I asked the owner if he had any docs from the inspection when this was discovered. He said he would have to look but he remembers it being quoted at 10-14k to repair.

How should I handle this? I like this deal, because I feel most people are going to turn away from this. Plus the guy wants to move out of state asap. So it has good negotiating potential.

Should I get a quote from a professional at the risk of wasting a few hundred dollars? Should I just negotiate with a worst-case scenario picture, and what would that be - 40k 60k?

Thanks!