Avoid real estate in following : During the Revolutionary War Philadelphia served as one of America's first capital cities. These days, however, Philadelphia could be considered the capital of toxicity, since the city and its environs ranked No. 1 on our 2011 Most Toxic Cities list. One big reason: The sprawling Philadelphia-Camden-Wilmington Metropolitan Statistical Area (MSA), including parts of four states (Pennsylvania, New Jersey, Delaware and one county in Maryland), is pocked with more than 50 Superfund sites -- areas no longer in use that contain hazardous waste. http://realestate.yahoo.com/promo/americas-most-toxic-cities-2011.html