You should consult with Clean Harbors, EPA, town board of health, dept. of engineering, public works and state environmental departments and they can give you specifics of the chemicals spilled, clean up actions taken & plans for monitoring in the future as well as potential harm from the chemicals. I don't have any knowledge if there even was a spill.
EDR also has a service where they can give specific info on types of environmental data available around a specific location. http://www.prudential.com/realestate if you go to the page under home search there's a tab for entering the address & it'll search around for reported problems. It's free, there is a more in depth report but that costs money. Might be a good place to start.