It is not just buildings. It is former military bases too. I have always thought we could pay off the national debt if we just sold off the Presido in downtown San Francisco.
Would you like some cesium-137 to go with your base? This is the problem with older property used during the 40’s and 50’s
http://cironline.org/reports/nuclear-byproduct-levels-treasure-island-higher-navy-disclosed-4362