The DEP coordinated the cleanup which involved excavating and hauling away several tons of contaminated soil.

Could they have attempted to remove it, but kept it in there because of contamination and never notified the town?

I think it all depends on: what the general practice is in your county, appetite of the lender to fund you knowing that there could be contamination issues, you're appetite and budget to get involved in what can be an extremely expensive remediation process, and the prevalence of tanks where the house is.

Like @Andrew Wong said, you do not want to create any liabilities with other possible contaminated or perishable food items.  

I can imagine a huge pissing contest as towhenther it's the originall site contamination or the other "plume".  

Dust contaminated with lead could be from poor house upkeep, children toys made in China, exterior emission if the property is located by a highway, or transfer from another owner occupant as in the case of the kid's grandparent house as the story listed in the Toledo Blade newspaper.  

Given this has been a salvage yard for 65 plus years I know that there will be soil contamination from the previous owners.

They've already done soil testing in several areas and no contamination has ever been found.

Maybe a crystal meth lab takes over the property next door and your place gets contaminated as well.

Then sadly in that 2 weeks the inspection supposedly came back with ground water/soil contamination.