The magazine compared the country's 40 largest metropolitan statistical areas.
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To create the ranking, Forbes "counted the number of facilities that reported releasing toxins into the environment, the total pounds of certain toxic chemicals released into the air, water and earth, the days per year that air pollution was above healthy levels, and the total number of Superfund sites -- contaminated areas that the federal government has designated for cleanup efforts -- in each metro area's principal city."
Top 10 Most Toxic Cities:
- Atlanta-Sandy Springs-Marietta
- Houston-Sugar Land-Baytown
- Los Angeles-Long Beach-Santa Ana