by Kristin M. Hall

About 5.4 million cubic yards of coal fly ash, a byproduct of burning coal, broke out of a retention pond at the Kingston Fossil Plant, Tennessee Valley Authority spokesman John Moulton said.

The TVA, which as the nation's largest utility company supplies electricity to 8.8 million people, first estimated that Monday's breach had spilled less than half that amount.

State environmental officials said Friday that their tests found the ash had not caused any problems near the intake for the local water treatment plant.

Moulton said TVA's first tests also showed no threat to the area's drinking water. The spill damaged 12 homes and covered 300 acres with sludge in Harriman, about 35 miles west of Knoxville.

"We are cleaning it up," he said. "That's where our efforts are focused and we are making some headway. Both on land and in the water, we are containing it and skimming it off the water."

State officials were also trying to stem the flow of the ash by building a submerged dam, or weir, across the channel of the Emory River to allow water to flow while catching the ash at the bottom.

Christopher Copeland, a resident whose land is covered in ash and debris, said he is not drinking the local water and is keeping his children inside until he can send them to a relative's house, "because I don't feel comfortable with them around here."

TVA "has done nothing to address our issues," Copeland said by phone Friday from his home on a road partially closed because of the spill.

Environmental activist groups said this week they also worry about the danger to drinking water.

An Environmental Protection Agency spokeswoman has said some toxic metals could be in the muck, including mercury and arsenic, but EPA tests were not finished. Dead fish were seen floating downstream, but the TVA said that could have been caused by freezing temperatures that may have contributed to the dike bursting.

State environmental officials found elevated contaminant levels in the immediate area of the spill, but not in the area of the intake for the Kingston Water Treatment Plant. The state reviewed samples taken by itself, the TVA and the EPA.

The state found there was no immediate risk from contact with the ash, as long as it wasn't eaten, according to a news release from the Tennessee Department of Environment and Conservation. But it was too early to speculate on the ash's long-term effects.

Environmentalists and the coal industry have argued for years over whether coal ash should be regulated as hazardous waste, which would make it subject to more stringent regulations.

In 2000, the EPA backed away from labeling it a hazardous waste but encouraged states to strengthen their regulations. Rick Hind, Greenpeace legislative director, said his group would ask President-elect Barack Obama's administration to renew efforts to regulate coal ash.

Greenpeace, an environmental activist group, is also asking for a criminal investigation into the failure of the pond and whether TVA could have prevented the spill. The pond is used for dumping waste from burning coal at the steam plant.

Hind said the new ash spill estimate shows the TVA doesn't know what is going on.

"In this case, locating it on a hill like this was probably the most foolish plan," he said. "This was so large and out of control that it took out everything in its path."

Copeland's house was not damaged, but his neighbor's was destroyed. Copeland is also keeping a watchful eye on a nearby cove that he says is normally 8 feet deep with water. He estimates it's now up to 16 feet and looks like it will overflow, probably into his house.

Hundreds of coal-fired plants across the country generate combustion byproducts, including ash. About 40 percent of that material is reused by mixing it with concrete or turning it into fill for highways or embankments, said David Goss, executive director of the American Coal Ash Association.

"But it does contain trace amounts of heavy metals, which was found in the coal," Goss said. "The concentrations are relatively small, but if you're talking about a million tons of ash, then you're going to measure the total of those constituents in the thousands of pounds."

Knoxville-based TVA supplies electricity to Tennessee, Mississippi, Alabama, Kentucky, Georgia, North Carolina and Virginia.

Associated Press Writer Juanita Cousins contributed to this report.