Early on the morning of December 22nd, 2008, more than a billion gallons of coal fly ash broke through a retaining wall at the Tennessee Valley Authority's Kingston Fossil steam plant in Harriman, Tennessee. The toxic sludge buried more than 300 acres of land and entered part of the Emory River. Chrissy Keuper interviews University of Tennessee professor Gregory Button, who studies environmental disasters and disaster recovery, including the Exxon Valdese Oil Spill and Hurricane Katrina. Button says the Kingston spill definitely qualifies as an environmental disaster... 