On Thursday, the federal utility wrote EPA that "in the interest of taking a conservative, self-critical approach," TVA reassessed the potential for harm as "high" for those living near the Bull Run and Cumberland coal-fired plants in Tennessee and the Colbert and Widows Creek plants in Alabama.
A "high" hazard ranking under the government's dam safety hazard system means that if a disaster happened it would likely result in economic and environmental damage and "will probably cause loss of human life."
"This is not based on risk of failure or probability of failure," TVA Chief Operating Officer Bill McCollum told The AP in an interview. "It is based on if you assume that an impoundment fails, then what are the potential consequences?"
McCollum said consultants hired after the massive coal ash spill Dec. 22 at TVA's Kingston Fossil Plant have found no signs of "imminent failure" at any of TVA's ash sites, though they have found much to repair and improve - and that work has already begun.
EPA released a list of 44 high risk sites in 10 states on June 30, none in Tennessee. The AP revealed that the list, at least in TVA's case, was based on a utility's own rating.
EPA spokeswoman Tisha Petteway said Thursday that EPA is "still collecting data on the sites" for its national report and a final list won't be ready until the end of the year.
The Tennessee Department of Environment and Conservation, which was not involved in the ratings, is more interested in preventing an ash site failure than predicting its toll, spokeswoman Tisha Calabrese-Benton said.
The environmental agency has a panel of experts and its own consultants reviewing TVA's analysis of what caused the Kingston failure while it monitors TVA's Kingston cleanup with EPA and considers future oversight.
"The bottom line is that we are working on many levels to ensure a disaster like the one at Kingston never happens in Tennessee again," she said.
John Kammeyer, a TVA vice president overseeing coal ash operations, said the federal utility will spend about $10 million on an engineering analysis of all of its ash sites by Stantec Consulting Services Inc. of Lexington, Ky. The consultants began work shortly after the Kingston spill.
He said another $14 million will be spent this year for immediate upgrades and maintenance on the sites.
McCollum said the operations of some sites already have changed, including lowering the level of water covering ash deposits. He said he expects TVA may close or replace some of its 26 ash impoundments over the next several years while converting some of the sites from wet-ash to dry-ash storage, reducing the risk of spills like Kingston's.
In the meantime, McCollum said TVA will be looking for ways to reduce the hazard potential of the sites, such as building barrier walls to minimize the impact of an ash pond failure.
"When we are finished we will have one of the most rigorously inspected, structurally sound and safe operating systems of storage impoundments in the industry," McCollum said.
TVA supplies electricity to about 9 million consumers through 158 distributors in Tennessee and parts of Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia.
