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America's 10 worst man-made environmental disasters

June 14, 2010, 12:50 p.m.
Coal ash spill in Kingston, Tennessee.

Photo: Wade Payne/AP

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Tennessee coal ash spill

A few hours before dawn on Dec. 22, 2008, the walls of a dam holding 1.1 billion gallons of coal ash crumbled, spilling the toxic concoction into the town of Kingston, Tenn., and creating the largest industrial spill in U.S. history. The wave of ash, leftovers from burning coal mixed with water, wiped out roads, crumpled docks and destroyed homes.

The ash had been stored at the nearby Tennessee Valley Authority coal power plant and contained a decade’s worth of arsenic, selenium, lead and radioactive materials. These metals can cause cancer, liver damage, neurological disorders and other health problems, but the EPA doesn’t classify coal ash as a hazardous material. As workers in Hazmat suits picked through the sludge, Kingston residents were told the ash didn’t present a serious health risk.

A Duke University study revealed that toxic elements in the coal ash could be suspended in the air, posing a serious health risk. The study also said that the coal ash contaminated waters and that accumulation of toxins in river sediment could poison fish. Residents have reported numerous health problems — headaches, respiratory problems and seizures, among others — and scientists have found high levels of toxins in the tissues of fish in the Tennessee, Clinch and Emory rivers.

The long-term effects of coal ash on humans and wildlife remain largely unknown, and experts say the impact of the Tennessee coal ash spill may take decades to sort out.