Selling land that may have been dump - How to find out for sure?

[Ken Sanders]

I'm in the process of selling a vacant plot of land and the consensus from the neighbors is that 50-100 years ago the Township was using this site as a trash dump. There was a house built on the land in the late 60s, but it was demolished a few years ago because of foundation issues attributed to the underlying soil.

The Township says that they know there are "soil issues" with the property, but they won't say how they know this. They claim to have no records of any such soil issues. I'm assuming they have to have some sort of basis for saying this other than gossip.

Is there a way to find out if there really was a trash dump on the property? I thought about heading the County Courthouse, but I don't even know what department might have this information.