As part of an ongoing comprehensive review of the structural integrity of coal ash impoundment sites nationwide, the U.S. Environmental Protection Agency (EPA) has concluded its review of an independent investigation at the Alliant Energy Corp.’s Interstate Power and Light facility in Burlington, Iowa.
The investigation finds that the five coal ash impoundments at the facility meet acceptable factors of safety, and EPA agrees with the findings of this investigation.
Agency officials announced in May that it would require Alliant to perform additional testing of the impoundments, or ponds, to ensure their safety and determine any necessary corrective actions.
Concerns about the ponds’ structural integrity were initially raised during a review of preliminary findings from a February report prepared by Alliant’s contractor, Aether DBS, which questioned whether some of the ponds at the Burlington facility met acceptable factor of safety ratings.
Subsequently, a more in-depth study by the contractor concluded that all of the ponds at the Burlington facility met acceptable factors of safety. A report of that study was provided last month to the agency.
EPA has been assessing the structural integrity of coal ash impoundments across the nation as part of its response to the December 2008 coal ash spill from a Tennessee Valley Authority facility in Kingston, Tenn. To date, EPA has conducted structural integrity assessments for more than 400 coal ash impoundments at 196 coal-fired power plants.