In response to a Freedom of Information Act (FOIA) request from several environmental groups, the EPA released a list of 584 coal ash dump sites around the country. Coal ash is the toxic leftover waste from coal-fired power plants. The list identifies wet coal ash dumps, which are more dangerous than dry landfills because they are more vulnerable to leaks, overflows, and failures. The information is central to protecting public health and the environment. Last December, a dike failed at a Tennessee Valley Authority (TVA) coal ash dump. The spill at the Kingston Fossil Plant in Harriman, TN sent more than 1 billion gallons of toxic sludge flowing into the nearby community and the Emory River.