The Kingston Fossil Plant coal fly ash slurry spill was an environmental and industrial disaster that occurred on Monday December 22, 2008, when a dike ruptured at a coal ash pond at the Tennessee Valley Authority's Kingston Fossil Plant in Roane County, Tennessee, releasing of coal fly ash slurry. The coal-fired power plant, located across the Clinch River from the city of Kingston, used a series of ponds to store and dewater the fly ash, a byproduct of coal combustion. The spill released a slurry of fly ash and water, which traveled across the Emory River and its Swan Pond embayment, onto the opposite shore, covering up to of the surrounding land. The spill damaged multiple homes and flowed into nearby waterways including the Emory River and Clinch River, both tributaries of the Tennessee River. It was the largest industrial spill in United States history.
The initial spill, which resulted in millions of dollars worth of property damages and rendered many properties uninhabitable, cost TVA more than $1 billion to clean up, and was declared complete in 2015. TVA was found liable for the spill in August 2012 by the U.S. District Court for the Eastern District of Tennessee. The initial spill resulted in no injuries or deaths, but several of the employees of an engineering firm hired by TVA to clean up the spill developed illnesses, including brain cancer, lung cancer, and leukemia, as a result of exposure to the toxic coal ash, and by the ten year anniversary of the spill, more than 30 had died. In November 2018, a federal jury ruled that the contractor did not properly inform the workers about the dangers of exposure to coal ash and had failed to provide them with necessary personal protective equipment.
Background
The Kingston Fossil Plant is located on a peninsula at the junction of the Emory River (to the north) and Clinch River (to the south and east), just over upstream from the latter's mouth along the Tennessee River. Watts Bar Dam, located along the Tennessee downstream from the mouth of the Clinch, impounds a reservoir (Watts Bar Lake) that spans a stretch of the Tennessee (to Fort Loudoun Dam), the lower of the Clinch (to Melton Hill Dam), and the lower of the Emory. The plant, originally known as the Kingston Steam Plant, began operations in 1954, primarily to provide electricity to atomic energy installations at nearby Oak Ridge. The plant contains nine units with a combined generating capacity of 1,398 megawatts, and burns about of coal every day. It was the largest coal-fired power plant in the world when it was completed.
The plant's ash pond disposal area is located immediately north of the plant along the Emory River shore, and was subdivided into three separate sections, the main ash pond, stilling pond, and dewatering pond, each for the different steps of the disposal process. The entire ash pond was impounded by a dike that rose above the winter level and above sea level. Fly ash is the fine particulate matter produced by the combustion of coal, which is collected rather than allowing it to escape into the atmosphere. Once this is complete in the wet disposal method, it is mixed with water and pumped into a retaining pond, known as the main ash pond at the Kingston Plant, where the ash gradually settled to the bottom. Once the particulate matter settled out, the water was pumped to the stilling pond, where the remaining solids settled, and the ash was dredged and moved to drying cells in the unlined above-ground dewatering pond, also known as the solid waste containment pond, where the spill took place. At the time of the spill, the dredge cells contained a watery slurry of fly ash generated by the burning of finely ground coal at the power plant.
TVA had reportedly known about the dangers of using wet storage ponds for coal ash since a 1969 spill in Virginia in which coal ash seeped into the Clinch River and killed large numbers of fish. TVA officials were also confirmed to have been aware of the toxicity of coal ash as early as 1981. In the 1980s, TVA engineers raised concerns about the stability of ash ponds. The utility repeatedly found leaks in levees and seepage in the soil at many of their ash ponds, including the ones at Kingston. However, TVA continued to make small repairs instead of switch to dry storage systems in an effort to reduce costs. At the time of the disaster, TVA was using wet storage at six of their 11 coal-fired power plants.