The toxic leftovers from burning coal for power are sitting in nearly 600 sites in 35 states, according to a federal survey released Tuesday.
Spills have occurred at 34 of those sites over the last decade.
Many of the spills were minor compared with the disaster that occurred at the Tennessee Valley Authority's power plant in Kingston, Tenn., in December. That spill, which flooded hundreds of acres of land, damaged homes and killed fish in nearby rivers, is not included in the data, although it triggered the EPA's March request of 61 power companies for information on how they manage coal combustion waste.
The survey is the most comprehensive list to date of coal ash storage sites and includes information submitted by 219 facilities.
The EPA said Tuesday that to date it had not received any information or detected any issues at the 584 coal ash storage sites identified that required immediate action.
But environmental groups, which obtained the data last week, said that the number of sites and the danger they pose to surrounding communities shows that coal ash ponds need federal regulation.
Coal ash is a byproduct of burning coal that can include heavy metals and other toxic contaminants. But no federal regulations or standards govern its storage and disposal, although the EPA has long recognized coal ash as a risk to human health and the environment and knows of 67 cases where it is known or suspected of polluting water.
EPA Administrator Lisa Jackson earlier this year said that the agency would consider federal rules, but it is unclear whether the ash will be controlled like household trash or under the more stringent rules for hazardous waste.
Jim Roewer, executive director of the Utility Solid Waste Activities Group, a consortium of electricity producers that includes many included in the EPA survey, said Tuesday that the data showed overall a good track record.
"There are no ticking time bombs," Roewer said. "We are confident that there is not another Tennessee Valley Authority waiting to happen."