America's Most Toxic Cities
Poor air quality, lack of clean water and a high rate of superfund sites make these metros most contaminated.
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.
Crowded urban areas are often thought of as the most polluted, but the latter isn't always caused by the former. While the Atlanta metro area takes top honors for toxicity, don't blame the city alone. The Atlanta metro includes the cities of Sandy Springs and Marietta, the sites of chemical plants, metal coaters and concrete factories. The cities have toxic-release levels equal at or higher than those Atlanta, in spite of populations that are 15% and 13% the size of Atlanta's, respectively.
Environmental advocates say weak regulations are to blame. "We struggle to have strong environmental leadership," says Jenette Gayer, policy advocate for Environment Georgia, an environmental advocacy organization. "For a lot of the chemicals people reported dumping, there are alternatives we should be helping them switch to."
Similarly, while the Philadelphia metro area is our fourth most toxic area, the City of Brotherly Love doesn't hold the bulk of the blame for the pollution. Factories in smaller Wilmington, Del., in the same metro area, reported releasing 57% more pounds of toxins than Philadelphia in 2007. Wilmington houses a Pepsi ( PEP - news - people ) bottler and General Motors assembly plant, as well as the headquarters of chemical company Dupont ( DD - news - people ).
Some cities, like Houston--our third most toxic city--contend with air that is far filthier than it should be. Facilities in Houston released 88.7 million pounds of toxic chemicals in the environment in 2007, and the former site of a methanol fire and chemical explosion number among the city's 50 Superfund locations. Factories that serve the local petrochemical industry emit benzene and 1-3 butabeine, toxins proven to be particularly harmful, that the area's intense sunlight and lack of wind keep trapped in the local area's atmosphere.
"Houston has an air problem," says Jim Lester, vice president of the Houston Advanced Research Center, a Woodlands, Texas-based nonprofit that studies and promotes sustainable development. "It has had one for a number of years, and we've been working on it extensively since about 2000."
Los Angeles, a city whose traffic-clogged freeways contribute to its famously poor air quality, experiences similar weather patterns that add to its existing air-quality problems. It ties for fourth most toxic city.
"Los Angeles is in a geographic basin surrounded by mountains," says Brian Turnbaugh, policy analyst for the Environmental Right to Know project at OMB Watch, a government watchdog organization. "The pollution doesn't go away; it kind of just sits there, creating these horrible smog days."
Big Lights, Clean City
High population density--the contrast to Atlanta's sprawl--can be a good thing in terms of toxicity. Limiting traffic has helped urban centers like New York City, which are often associated with grit and grime. A highly efficient subway system keeps New York outside the worst 20 cities in terms of toxicity.
"New York City has extremely high density, but excellent public transportation," says Turnbaugh. Still, the area is more toxic than 18 of the large cities we looked at, proving that cracking down on waste and emissions is a complex, long-term problem. "The public transportation system can only accomplish so much, given that you've got people coming and going from outlying areas."
Some cities, like Portland, Ore., have avoided becoming highly toxic by devoting city resources to environmentally friendly planning.
"Portland is known for its innovative land-use policies," says Turnbaugh. The city has been working to curb urban sprawl and encourage density since the 1970s. But Portland has underlying problems that make it more toxic than half the cities we surveyed. "It was suffering, for years, from out-of-control growth. Those policies were a reaction to that."
Portland and New York demonstrate the myriad and wide-ranging causes of toxicity. No one measure is enough to completely address the problem, nor can one solution apply to all toxic cities. These two cities themselves couldn't be more different in terms of size or lifestyle, yet they're next to each other on our list.
"I don't know of any metro area that has really nipped it in the bud," says Turnbaugh of the effort to assess and clean urban toxicity. But a silver lining has emerged from the negative focus that one of the country's most toxic city has attracted: Houston, of all places, is now a vanguard for advancing sustainability.
"We're now one of the favorite places in the world for doing air-quality science," says Lester. "The more people understand about it, the more changes are likely that will take us in a positive direction."
(read online version)