An Eastern Tennessee community is facing an environmental horror this Christmas holiday after a massive coal-sludge pond collapsed Monday at the Tennessee Valley Authority's Kingston power plant in Roane County. The collapse released at least 1.7 million cubic yards of fly ash, the heavy-metal and radiation-laden waste left after burning coal.

The toxic sludge has covered some 400 acres of land four to six feet deep and damaged at least a dozen homes, including one that was pushed off its foundation. The fly ash has also blocked the Emory River, a tributary of the Tennessee, which provides drinking water for millions of people living downstream. There are already reports of fish kills related to the spill, which could take months or even years to clean up.

TVA President and CEO Tom Kilgore -- who likened the appearance of the ruined land to a "moonscape" -- says he and his company "deeply regret" what happened.

"Protecting the public, our employees, and the environment is TVA's primary concern as we supply electric power for the people of Tennessee Valley region," he says.

But there are questions about how seriously TVA took it responsibility for protecting the public. At a press conference today, Kilgore released inspection reports showing there have been two other breaches of the same fly ash pond over the past six years.

Greenpeace has called for a criminal investigation into what it charges was TVA's failure to prevent the disaster, while the Southern Environmental Law Center says the incident shows the need for better government regulation of coal combustion waste, which was the focus of a congressional hearing held earlier this year. The disaster also undercuts the claims made by the electric power industry's "clean coal" marketing campaign, which this year included a controversial series of re-worked Christmas carols touting coal's cleanliness.

"This holiday disaster shows that there really isn't such a thing as a clean coal plant," says attorney Chandra Taylor of the Southern Environmental Law Center. "From mountaintop removal mining to smokestacks spewing soot and smog to ash ponds full of toxins, coal power is dirty -- plain and simple. Nobody wants to find coal in their Christmas stocking, let alone coming through their home and polluting their river."

To witness coal's dirty truth, watch the TVA video showing the devastating aftermath of Monday's spill, which was the source of the still photo above.