One of my summer Urban Environmental Policy students - thanks, Jenna! - found an awesome online service, ToxMap, courtesy of the National Library of Medicine. http://toxmap.nlm.nih.gov/toxmap/home/welcome.do
With this online resource, you can create a Geographical Information Systems [GIS] map of any area in the U.S., showing contaminated sites and sites identified through the Toxic Release Inventory [TRI] by any one or multiple toxic elements.
Once you find what you're looking for, you can pull down specifics: Maybe you've asked to see accidental releases, and you want to see which company is responsible for the leak. Maybe you want to see all the sites in a particular geographic area where toxins are being stored. Maybe you want to see all the Superfund (contaminated groundwater clean-up sites).
Because of a particular exercise my students did in class, I decided to ask for an Arizona map showing Toxic Release Inventory [TRI] sites. Those are sites that manufacture, transport, use, or store chemicals that are considered toxic by the EPA.
Suppose you want to find all the companies with a TRI for a particular chemical - say benzine. Once you locate these, TOXMAP will give you company data.
The site has a full data base of educational material.
This site just has a wealth of information, whether you just want to know what's going on in your own backyard, or you need information for a project.
The site provides a very good, fast "how to" video, here: http://toxmap.nlm.nih.gov/toxmap/tour/misc/ToxmapBasics.html. I did try to find a video on YouTube so you didn't have to actually go to the link, but there apaprently isn't one.