The toxic red sludge that engulfed the streets of a Hungarian town this week appears almost alien, but toxic waste is a very real threat for millions people in the United States.
Coal ash, a byproduct of coal power plants, is stored in largely unregulated dumps across the country, and retaining walls holding in the toxic material occasionally give way.
A large coal ash spill near Kingston, Tenn. destroyed homes and scarred the environment in a 300-acre area in December 2008.
The coal ash contains heavy metals such as lead and mercury that potentially can cause birth defects, cancer and other health problems.
Just last week, there was a much smaller coal ash spill in Wilmington, N.C. The breached pit didn't present a threat to the public, but it served as a fresh reminder of the standing pools of ash that remain nationwide.
While the federal government does not consider coal ash a hazardous material, plenty of other toxic dumps are being tracked by authorities.
The federal government's Superfund program was enacted in 1980 by President Jimmy Carter, charged with identifying uncontrolled hazardous waste sites around the country.
Three decades later, there are 1,282 active sites on the "National Priorities List," the government's short list of Superfund sites so hazardous that they merit long-term clean up.
NPL sites dot every state in the nation, located in both major population centers and rural areas, with hundreds of millions of Americans living nearby.
Sites can be found everywhere from densely populated Brooklyn, N.Y., where the Gowanus Canal contains dangerous pollutants, to Conroe, Texas, where chemicals from a wood-treating facility leached into the groundwater.
For resources on how to find hazardous sites near you, click on the links below: