(NBC News) - The Environmental Protection Agency is set to issue its first ever guidelines on the handling and storage of coal ash.
The waste produced by coal-fired power plants is at the center of a marathon legal battle, and a federal judge has given the EPA until Friday to decide just how much a threat coal ash poses.
The move comes after two massive coal ash spills.
Days before Christmas 2008 a dike at a Tennessee power plant failed and a billion gallons of coal ash and water nearly wiped a nearby town off the map.
This past February a storm water pipe burst at another plant in North Carolina, sending 39,000 tons of coal ash into the Dan River.
America gets 39 percent of its energy from coal and coal ash is what's left behind.
Storage sites are located in 33 states and sites in a dozen states are considered to have a significant or high hazard potential.
Environmentalists claim coal ash poses a long-term health hazard to millions of Americans.
"Coal ash is a dangerous substance that has toxic chemicals in it, like mercury, like lead, like arsenic," notes the Sierra Club's Mary Anne Hitt.