The TVA Kingston Fossil Plant coal fly ash slurry spill occurred just before 1 a.m. on Monday December 22, 2008, when an ash dike ruptured at an 84-acre solid waste containment area at the Tennessee Valley Authority's Kingston Fossil Plant in Roane County, Tennessee, USA. 1.1 billion US gallons of coal fly ash slurry was released. The coal-fired power plant, located across the Clinch River from the city of Kingston, uses ponds to dewater the fly ash, a byproduct of coal combustion, which is then stored in wet form in dredge cells. The slurry (a mixture of fly ash and water) traveled across the Emory River and its Swan Pond embayment, on to the opposite shore, covering up to 300 acres (1.2 km2) of the surrounding land, damaging homes and flowing up and down stream in nearby waterways such as the Emory River and Clinch River (tributaries of the Tennessee River). It was the largest fly ash release in United States history. Coal slurry spill was an accident that occurred after midnight on October 11, 2000 when the bottom of a coal slurry impoundment owned by Massey Energy, broke into an abandoned underground mine below. The slurry came out of the mine openings, sending an estimated 306,000,000 US gallons of slurry down two tributaries of the Tug Fork River. By morning, Wolf Creek was oozing with the black waste; on Coldwater Fork, a 10-foot (3.0 m) wide stream became a 100-yard (91 m) expanse of thick slurry. The spill was over five feet deep in places and covered nearby residents' yards. The spill polluted hundreds of miles of the Big Sandy River and its tributaries and the Ohio River. The water supply for over 27,000 residents was contaminated, and all aquatic life in Coldwater Fork and Wolf Creek was killed. The spill was 30 times larger than the Exxon Valdez oil spill (12 million US gallons) and one of the worst environmental disasters ever in the southeastern United States, according to the United States Environmental Protection Agency.