The Environmental Protection Agency put hundreds of mountaintop coal-mining permits on hold Tuesday to evaluate the projects' impact on streams and wetlands.

The decision by EPA Administrator Lisa Jackson targets a controversial practice that allows coal mining companies to dump waste from mountaintop mining into streams and wetlands.

The permits are issued by the Army Corps of Engineers, an agency that has been criticized by environmental groups and has been sued for failing to thoroughly evaluate the environmental impact of mountaintop removal.

Under the Clean Water Act, companies cannot discharge rock, dirt and other debris into streams unless they can show that it will not cause permanent damage to waterways or the fish and other wildlife that live in them.

Last month, a three-judge appeals panel in Richmond, Va., overturned a lower court's ruling that would have required the Corps to conduct more extensive reviews. The appeals court decision cleared the way for a backlog of permits that had been delayed until the lawsuit was resolved.

The EPA said in a statement that it would be actively involved in the review of the long list of permits awaiting approval by the Corps, a signal that the agency under the Obama administration will exercise its oversight.

The EPA has the authority to review and veto any permit issued by the Corps under the Clean Water Act, but under the Bush administration it did that rarely.

If the EPA didn't step in and do something now, all those permits would go forward, said Joe Lovett, executive director for the Appalachian Center for the Economy and the Environment. There are permits that will bury 200 miles of streams pending before the Corps.

The EPA action stunned the coal industry, which had been breathing easily since the mid-February ruling by the 4th Circuit Court of Appeals.

Mountaintop mines in West Virginia, Virginia, Kentucky and Tennessee produce nearly 130 million tons of coal annually - about 14% of the nation's power-producing coal - which in turn generates electricity for 24.7 million U.S. customers, according to industry estimates.

In a separate action, the EPA recommended denying permits the Army Corps of Engineers was planning to issue that would allow two companies to fill thousands of feet of streams with mining waste in West Virginia and Kentucky.