 These stacks were replaced with a single stack connected to scrubbers which were installed in 2007.In December 2008, an impoundment at the plant failed, releasing of coal fly ash slurry that covered up to of the surrounding land, damaging homes and flowing into nearby waterways such as the Emory River and Clinch River, tributaries of the Tennessee River.This was the largest accidental release of coal fly ash in the United States.