“Coal ash” is the generic term for wastes that are leftover after coal is burned in electric generating plants or industrial boilers. More specifically known as coal combustion wastes or residuals, they include fly ash, bottom ash, flue gas desulfurization (scrubber) sludge, and boiler slag.2 Over 109 million tons were generated in the U.S. in 2012, down from 130 million tons in 2011. The amount of coal ash generated is more than three times the annual amount of hazardous waste generated in the U.S.
CONSEQUENCES OF LAX COAL ASH OVERSIGHT
Coal ash is exempt from federal regulation as a hazardous waste, pursuant to two separate U.S. EPA regulatory determinations. But due to mounting evidence of the health and environmental threats posed by poor coal ash disposal practices, the EPA in June 2010 proposed two options for a new federal rule to regulate coal ash disposal in landfills and surface impoundments.
There are 208 cases, in 37 states, of known groundwater contamination and surface water spills throughout the country. The serious risks of poorly regulated coal ash disposal received widespread public attention in December 2008 when a dam failed at the Tennessee Valley Authority’s Kingston power plant, releasing 1 billion gallons of coal ash sludge into the Emory River.
Although not on the same scale, similar spills occurred at Indianapolis Power and Light’s Eagle Valley power plant near Martinsville, Indiana in 2007 and 2008. Roughly 60 million gallons of coal ash sludge were released to the West Fork White River after the same pond levee failed twice. None of the coal ash sludge released to the river was recovered.
The most recent major coal ash spill occurred in North Carolina in February 2014. Roughly 39,000 tons of coal ash spilled into the Dan River when a stormwater pipe underneath coal ash ponds at Duke Energy’s Dan River power plant failed, allowing the ash sludge to drain into the pipe and then to the river.
At Duke Energy’s Wabash River power plant near Terre Haute, a seven-foot diameter corrugated metal pipe runs beneath one of the power plant’s coal ash ponds. This is the same type of pipe that failed at Duke Energy’s Dan River plant.
Three main pathways exist for the release of coal ash or its contaminants to humans and the environment:
1. Coal ash and its constituents pose a health hazard through inhalation as airborne particles.
2. Coal ash and ash pond wastewater are directly released to surface water, through overflows or dam/levee breaches potentially resulting in contaminated fish that are consumed by humans.
3. Leachate from coal ash in unlined ponds can infiltrate groundwater that is used as drinking water.
HEALTH AND ENVIRONMENTAL RISKS
Coal deposits naturally contain trace elements including metals such as arsenic, selenium, lead, mercury, and chromium. When the coal is burned, many of the trace elements remain in the ash and are susceptible to leaching — the process by which toxic materials in coal ash dissolve in water and percolate through the earth. The dissolved toxins, called “leachate,” can endanger public health and the environment by contaminating surface water or groundwater used for drinking supplies.
The pathways for coal ash to reach humans include:
– Drinking well water contaminated with metals and other substances contained in coal ash;
– Breathing airborne (fugitive) coal ash dust;
– Contact with contaminated surface waters or consuming contaminated fish.