The U.S. Environmental Protection Agency (EPA) initiated a seldom-used review process that could eventually block the development of the Pebble Mine in Alaska.

Citing potential "irreversible harm" to the state's salmon fishery, the EPA can use the Clean Wa-ter Act to effectively veto the mine with a process that has been started just 29 times and com-pleted 13 times. The review process includes a new consultation period, public hearings and further consultation with Army Corps of Engineers, Reuters reported.

Permits cannot be approved during the review process.

The Pebble Mine, if built near the Bristol Bay region of Alaska, could be one of the largest cop-per mines in the world, but the Bristol Bay is home to the largest salmon habitats in the world.

The EPA decision follows a draft report in January that found large-scale mining could pose se-rious risks to salmon and native cultures in the pristine corner of southwest Alaska.

"Extensive scientific study has given us ample reason to believe that the Pebble Mine would likely have significant and irreversible negative impacts on the Bristol Bay watershed and its abundant salmon fisheries," EPA administrator Gina McCarthy said in a statement.

"This process is not something the agency does very often, but Bristol Bay is an extraordinary and unique resource."

Northern Dynasty Minerals, majority owner of the project, condemned the EPA's action, saying the agency is looking to preemptively block the project without allowing it to go through the es-tablished permitting and environmental review process.

"What the EPA is trying to do is short-circuit that process," Tom Collier, chief executive of the Pebble Limited Partnership, a Northern Dynasty subsidiary, told Reuters. "That's just a huge mistake. That's not the way America works."

Alaska Sen. Lisa Murkowski (R-AK) again spoke out against the EPA's involvement with the project. She repeated the accusation that the EPA's actions constitute a "premature veto," given that Northern Dynasty, has yet to submit an official proposal or permit applications.

"We already have undeniably grave problems with federal agencies blocking resource produc-tion on federal lands in Alaska," Murkowski wrote. "Now to see a federal agency overstep its authority and move prematurely to block even the consideration of a permit for potential activity on state lands is something I simply cannot accept."

But the Senator also pointed out that for the past three years she's been calling on the project's owners to submit their plan "so that Alaskans have greater certainty about its expected benefits and impacts."

In letters to the U.S. Army Corps of Engineers, the state of Alaska, and the Peb-ble Partnership informing them that EPA was initiating action under the agency’s Clean Water Section 404(c) authorities. 

The Clean Water Act generally requires a permit under Section 404 from the Army Corps of Engineers before any person places dredge or fill material into wetlands, lakes and streams. “Mining operations typically involve such activities and must obtain Clean Water Act Section 404 permits,” said the EPA.

Northern Dynasty said it remains confident that Pebble will eventually move ahead and has said the mine can be developed in a safe manner and would provide an economic boom for Alaska.

Northern Dynasty expects to employ about 2,500 people through the construction phase and then about 1,000 throughout the mine's operating life, and filter hundreds of millions in tax dol-lars to federal, state and regional governments each year.

Northern Dynasty lost its project development partner last September when mining group Anglo American pulled out of the venture.