A look at 3 of the largest coal ash spills in the US

The Obama administration on Friday set the first national standards for waste generated from coal burned for electricity, called coal ash, treating it more like household garbage rather than a hazardous material. The Obama announcement ended a six-year effort that began after a massive spill of the ash that contains toxins at a Tennessee power plant in 2008. Since then, the EPA has documented coal ash waste sites tainting hundreds of waterways and underground aquifers in numerous states with heavy metals and other toxic contaminants.

Here is a look at the three largest coal ash spills in the U.S.

DECEMBER 22, 2008 — A containment dike bursts at a coal-fired power plant in Kingston, Tennessee, releasing more than 5 million cubic yards of toxin-laden coal ash from a storage pond. The sludge flowed into the Emory and Clinch rivers and destroyed homes in a nearby waterfront community.

The huge spill also drew national attention to coal ash and its toxic contaminants.

The Tennessee Valley Authority is spending $1.2 billion on cleanup and restoration of the area, with work expected to be completed in spring 2015. About 500,000 cubic yards of ash will be left at the bottom of the rivers because it was determined that dredging them would stir up contaminants. TVA has agreed to monitor the site for 30 years at a cost of about $10 million.

OCTOBER 31, 2011 — Tons of coal ash and debris were swept into Lake Michigan after a cliff gave way on the grounds of a We Energies coal-fired power plant near Milwaukee.

The collapse created a mudslide that sent a pickup truck and other equipment tumbling into Lake Michigan, swept several construction trailers toward the beach and left a swath of soil, ash and debris as large as a football field. There were no injuries or power disruptions.

The Wisconsin Department of Natural Resources estimated that about 2,500 cubic yards of ash reached the water. The spill happened well away from the drinking water intakes for nearby communities.

FEBRUARY 2, 2014 — An estimated 39,000 tons of coal ash spewed into the Dan River after a drainage pipe running below a waste dump collapsed at a Duke Energy plant in Eden, North Carolina. The toxic sludge turned the river gray for more than 70 miles.

By July, Duke had dredged up about 2,500 tons of ash and contaminated sediment that settled against a dam in Danville, Virginia. Another 500 tons had been recovered from other pockets in the river and settling tanks at two municipal water treatment plants in Virginia.

A U.S. Environmental Protection Agency on-scene coordinator said the cleanup was considered complete, although Duke had recovered only a fraction of the total spilled. In August, North Carolina lawmakers approved legislation directing that more than 30 ash dumps be capped or removed by 2029.