Estimated Number of Potentially Contaminated Sites: Department of Defense = 21,400, Department of the Interior= 26,000 , Department of Energy also has at least 10,000 sites with hazardous and radioactive wastes. Guess who foots the bill to clean up? Doesn't tally the amount of lives that have been affected/lost by exposure. http://www.epa.gov/fedfac/docum ents/puzzle.htm