I finally got in touch with a guy at the Department of Environmental Quality. He stated that any soil contamination was limited to the actual site of the plume, which is in the railroad yard about 1.5 miles away. Hurray for that. There are several sites where the groundwater is contaminated, but, luckily, nothing near us, and those sites were mostly personal wells.
So, we are all good to go! I am very relieved and excited.