America's Most Toxic Cities

In Atlanta, Ga., you'll find southern gentility, a world-class music scene--and 21,000 pounds of environmental waste. In spite of its charms, the city's combination of air pollution, contaminated land and atmospheric chemicals makes it the most toxic city in the country.

An urban skyline dotted with puffing smokestacks isn't the only measure of a city's cleanliness (or lack thereof). Most major cities suffer from a range of unseen hazards. Contaminants can seep into the ground from bygone chemical spills or shuttered steel mills. Invisible leaks at industrial complexes discharge harmful substances into the air, or the normal course of business requires factories to expel toxins that eventually find their way to the water supply.

While it may be the U.S. metro in the worst environmental shape, Atlanta isn't the only place whose residents contend with contamination. Top spots for toxicity are distributed throughout the country, with Detroit, Houston, Chicago, Philadelphia, Cleveland and Los Angeles right behind it.

Behind the Numbers
To determine which cities are most toxic, Forbes looked at the country's 40 largest metropolitan statistical areas--geographic entities that the U.S. Office of Management and Budget defines and uses in collecting statistics--in the country, based on data provided by the U.S. Environmental Protection Agency. We 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.

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