Jan 2 - McClatchy-Tribune Regional News - Bruce Henderson The Charlotte Observer, N.C

 An East Tennessee spill that covered 300 acres in toxic sludge has renewed scrutiny of coal ash, which accumulates by millions of tons at Charlotte-area power plants.

The ash -- coal-burning residue stored in open basins -- is laden with metals that in high concentrations can cause cancer and other health problems.

Duke Energy's eight Carolinas coal-fired plants produce 2.2 million tons of ash a year, two-thirds of it dumped into landfills and ponds. Groundwater contamination forced Duke to close one ash landfill this year, the Observer reported in February. The company is installing wells to detect tainted groundwater at its plants.

But the Tennessee spill raised a different question about ash basins: the stability of earthen dams that contain them.

A dike at the Tennessee Valley Authority's Kingston power plant, 40 miles west of Knoxville, collapsed Dec. 22 after heavy rain. Angry residents have accused federal authorities and the TVA of being slow to say what was in the 5.4 million cubic yards of sludge or to assess its environmental damage.

The Knoxville-based Southern Alliance for Clean Energy said Tuesday it might sue the TVA over damage to the Emory and Clinch rivers. Gary Davis, a Hot Springs, N.C., lawyer representing the group, said it's too soon to say whether Tennessee dam-safety regulations were lax.

Duke, which operates 10 ash basins, and the N.C. Utilities Commission reviewed recent dike inspection reports following the TVA spill. The most recent inspections at Duke's plants found no imminent instability.

"We reviewed all inspections to date, and we're confident in those inspections," said Duke spokesman Tim Pettit.

But the reports, reviewed by the Observer, describe potential problems at dikes that are as much as 90 feet high and 3,000 feet long:

A "potentially serious seepage issue" at Duke's Dan River power plant in Rockingham County, near the Virginia line. A 2007 inspection report recommended further investigation of the dike's stability.

A 2005 storm overtopped a dike at the Cliffside plant in Rutherford County, 50 miles west of Charlotte, causing "major distress and erosion." The dike had to be heightened by a foot.

More often, the reports recommend monitoring of instruments to detect instability, cutting vegetation and controlling muskrats.

The state labels coal-ash dikes at Duke's Marshall, Riverbend, Buck and Dan River plants as "high hazard." The labels aren't based on how safe the dams are, but on the amount of environmental damage and financial loss that could result if they failed.

The Utilities Commission, which regulates Duke, requires independent safety inspections of coal-ash basins every five years. Pettit said Duke voluntarily does annual inspections, although state records show lapses at some plants.

The state dam-safety office, part of a separate agency, reviews the inspection reports and Duke's responses.

Roy Ericson, a commission official who has reviewed inspection reports since 2002, said he can't remember a case in which inspection recommendations weren't followed.

"There's a lot of technical review to make sure they're safe," he said, "and the interests of the utilities are that they stay that way."

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