On December 22, 2008, more than a b

On December 22, 2008, more than a billion gallons of coal fly ash spilled when a dike burst on a retention pond at the Kingston Fossil Plant (also called Kingston Steam Plant) operated by the Tennessee Valley Authority (TVA) in Roane County. The catastrophic failure is the largest environmental disaster involving a spill of coal ash in the Southeast.

Coal ash is the byproduct of burning coal and is considered toxic. The ash ponds at the Kingston coal plant were separated from a nearby river only by earthen dikes, and not stored in lined landfills. You can click here to watch a YouTube video of the spill.

To date, at least three homes have been destroyed and scores of properties have been damaged. Concerns have been raised as to the impact of the contamination on groundwater supplies and air quality as well as effects on the local economy and property values.

Testing of river water near the spill showed elevated levels of lead and thallium, which can cause birth defects and nervous and reproductive system disorders, as well as high levels of arsenic. In addition, leaks and seepage plagued the retention pond at the TVA coal plant for years. According to a February 2008 inspection report, the TVA reportedly knew about leaks at the Kingston facility for more than two decades and opted not to pay for long-term solutions to the problem.

KINGSTON, Tenn. — They live next to one of the nation's worst spills of toxic ash at a coal-burning power plant, and they're scared:

• Crystal Hamby has not let her two young children play outside in more than a week; she says that they've developed suspicious coughs and that she's terrified for their safety.

• Joanie Smith worries about her 15-year-old daughter and the four horses she uses to teach children to ride. Parents are canceling scheduled lessons because they're afraid to bring their children into the area, Smith says.

• Jot Raymond says no one wants to buy houses in a subdivision he's developing and he doesn't blame them: He's scared about the long-term health of his 18-month-old twin grandsons and another grandchild yet in the womb.

The Tennessee Valley Authority is working feverishly to contain and clean up millions of cubic yards of toxic ash that spilled Dec. 22 into a river and over an area the size of a small downtown. No one was seriously injured.

The spill at Kingston Fossil Plant, which was the world's largest coal-burning power plant when it opened in 1955, occurred when walls of an above-ground storage pond gave way. The ash waste, which was stored in a massive "dredge cell" 55-60 feet high, turned into a gooey sludge containing arsenic and heavy metals.

The piles of ugly, gray mess created a huge mudslide-like effect that destroyed three houses, displaced a dozen families and damaged at least 42 properties. The sludge spread across 300 acres and into the Emory River. It created an alien-looking landscape that resembles no recent natural disaster.

"We don't know what the long-term environmental effects of something this size are," Tennessee Gov. Phil Bredesen said Wednesday after viewing the damage. "We can speculate all we want or like, but to my knowledge, there's not been one this large in the past in this country."

It's that uncertainty — fear of the unknown — that's generating so much concern here. "This could be something that shows up in five or 10 years," says Raymond, 58. "It's not what's happening to people right now, it's what could happen to our children and grandchildren years down the road."