The Kingston Fossil Plant Spill was an environmental and industrial disaster that occurred on 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 1.1 billion US gallons (4.2 million cubic metres) 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 300 acres (1.2 km2) 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 more than 30 had died within 10 years of the spill. 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. After rejecting multiple offers, workers reached a settlement with the contractor in May 2023.
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 four miles (6.4 km) upstream from the latter's mouth along the Tennessee River. Watts Bar Dam, located along the Tennessee 38 miles (61 km) downstream from the mouth of the Clinch, impounds a reservoir (Watts Bar Lake) that spans a 72-mile (116 km) stretch of the Tennessee (to Fort Loudoun Dam), the lower 23 miles (37 km) of the Clinch (to Melton Hill Dam), and the lower 12 miles (19 km) 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 14,000 short tons (13,000 metric tons) 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—for the different steps of the disposal process. The entire ash pond was impounded by a dike that rose 60 feet (18 m) above the winter level and 741 feet (226 m) 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 ash collection 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 84-acre (0.34 km2) 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 switching to dry storage systems in an effort to reduce costs. At the time of the disaster, TVA was using wet storage at six of its 11 coal-fired power plants.
Leaks at the Kingston ash ponds had reportedly been taking place since the early 1980s, and local residents said that the spill was not a unique occurrence. The 1960s-era pond had been observed leaking and being repaired nearly every year since 2001. The two worst leaks occurred in 2003 and 2006 in which TVA suspended all ash deposits in the ponds to allow the dredge cells to dry out and stabilize. An October 2008 inspection report had identified a small leak in the faulty wall, but the report was not yet complete at the time of the spill.
Event
Dike breach and spill
The spill began sometime between midnight and 1 a.m. Eastern Standard Time on December 22, 2008, when the dike surrounding the ash containment dewatering pond broke. The breach occurred at the northwest corner of the dewatering pond, overlooking the Swan Pond Creek spillway. The spill consisted of an initial large wave which lasted for approximately one minute, followed by a series of smaller consecutive waves of breaking away and sliding that occurred over a period of approximately one hour.
TVA and the Environmental Protection Agency (EPA) initially estimated that the spill released 1.7 million cubic yards (1.3 million cubic metres) of sludge, which is gray in color. After an aerial survey, the official estimate was more than tripled to 5.4 million cu yd (4.1 million m3) on December 25, 2008.
Effects
The spill covered the surrounding land with up to six feet (1.8 m) of sludge. Although the land surrounding the power plant is largely rural, the spill caused a mudflow wave of water and ash that covered 12 homes, pushing one entirely off its foundation, rendering three uninhabitable, and caused some damage to 42 residential properties. It also washed out a road, ruptured a major gas line, obstructed a rail line, preventing a train delivering coal from reaching the plant, downed trees, broke a water main, and destroyed power lines. Though 22 residences were evacuated, nobody was reported to be injured or in need of hospitalization. However, research shows that the event had significant negative effects on mental health for people affected and in the area. It was the largest industrial spill in United States history, more than three times the size of the Martin County coal slurry spill of 2000, which spilled 306 million US gallons (1.16 million cubic metres) of slurry. The 1.1 billion US gal (4.2 million m3) of sludge were enough to fill 1,660 Olympic-size swimming pools, and the volume released was about 100 times larger than the 1989 Exxon Valdez oil spill and about 10 times greater than the volume released in the 2010 Deepwater Horizon oil spill, the largest oil spill in history.
The next day, TVA spokesman Gil Francis Jr. stated that, at the time of the spill, the area contained about 2.6 million cubic yards (2.0 million cubic metres) of ash and that two-thirds of that had been released, which would later be found to cover an area of 300 acres (1.2 km2). The New York Times noted that the amount spilled was larger than the amount stated to have been in the pond before the spill, a discrepancy the TVA was unable to explain. The spill did not affect the adjacent retaining and stilling ponds; the other two stayed intact, while only the retaining wall for the 84-acre (0.34 km2) solid waste containment area was affected.
The spill was reported to have killed and buried multiple deer and at least one dog, and ejected fish from the Emory River onto the river bank as far as 40 feet (12 m) from the shore. The contamination effects in the rivers killed an extremely large number of fish and other aquatic life. Large numbers of dead fish were reported as far as the Tennessee River and other area tributaries in the aftermath of the spill.
Cause
Engineering firm AECOM was hired by TVA to investigate the cause of the spill. A report released in June 2009 identified the main cause of the spill as the result of slippage of an unstable layer of fine wet coal ash underneath the pond. The report also identified other factors, including the terraced retaining walls on top of the wet ash, which narrowed the area for storing the ash and in turn, increased the pressure exerted on the dike by the rising stacks. The Kingston Fossil Plant had received 6.48 inches (165 mm) of rain between December 1 and December 22, plus 1.16 inches (29 mm) on November 29 and 30. This rain combined with 12 °F (−11 °C) temperatures were identified by TVA as factors that contributed to the failure of the earthen embankment.
Response
Response from officials
We deeply regret that a retention wall for ash containment at our Kingston Fossil Plant failed, resulting in an ash slide and damage to nearby homes.
— TVA statement released the day after the spill.
The day after the spill, TVA released a statement acknowledging the spill and apologizing for its damage to nearby homes. Francis said that the TVA was "taking steps to stabilize runoff from this incident." Residents and environmental groups expressed concern that the fly ash slurry could become more dangerous once it dried out. On January 1, 2009, the TVA disseminated a fact sheet stating that the ash is "not hazardous."
Tennessee Governor Phil Bredesen toured the spill site on December 31. The United States Senate Committee on Environment and Public Works, which oversees the TVA, held a hearing on January 8 to examine the disaster. Witnesses included Tom Kilgore, president and chief executive officer of the TVA; Stephen A. Smith, executive director of the Southern Alliance for Clean Energy; and William "Howie" Rose, director of emergency management services for Roane County. The hearing examined the causes and consequences of the spill, the TVA's response, and the management of coal ash waste. Environmental activist Erin Brockovich visited the site on the same day and spoke with residents affected by the spill.
Water quality and efforts to stop the spill
Immediately after the spill, the EPA and Tennessee Department of Environment and Conservation (TDEC) began testing the water quality of the area affected by the spill. Although residents feared water contamination, early tests of water six miles (10 km) upstream of the ash flow showed that the public water supply met drinking water standards. A test of river water near the spill showed elevated levels of lead and thallium, and "barely detectable" levels of mercury and arsenic. On January 1 the first independent test results, conducted at the Environmental Toxicology and Chemistry laboratories at Appalachian State University, showed significantly elevated levels of toxic metals, including arsenic, copper, barium, cadmium, chromium, lead, mercury, nickel, and thallium in samples of slurry and river water.
The day after the spill Tennessee Emergency Management Agency indicated that barriers would be constructed to stop the ash from reaching the Tennessee River. By early on December 24 a flyover by The New York Times did note repair work being done on the nearby railroad, which had been obstructed when 78,000 cubic yards (60,000 m3) of sludge-covered tracks. By the afternoon of that day, dump trucks were being used to deposit rock into the Clinch River to prevent the further downstream contamination. The TVA also slowed the river flow, for the same purpose. The slurry that was cleared from Swan Pond Road was brought back to one of the plant's intact containment ponds. By December 30 the TVA had announced it was requesting the assistance of the Army Corps of Engineers to dredge the ash-filled Emory River to restore navigation. On January 1 the TVA announced that rather than attempting to clear away all of the slurry, they would be spraying seed, straw, and mulch on top of much of it to prevent dust scattering and erosion.
In response to independent attempts at sampling of the water quality and the taking of photos, the TVA illegally detained, for approximately one hour, two members of the Knoxville-based environmental organization United Mountain Defense who were traversing public land in the area of the spill and warned three other individuals that any attempt to enter the public waterway would lead to prosecution. On December 26 TDEC stated that it was satisfied with the water quality in the wake of the spill but that it would continue to examine and deal with the potential for chronic health effects.