A decision from the Department of Interior to review energy exploration plans off the coast of Alaska is "unconscionable," environmental groups said.

The federal government affirmed a 2008 lease sale for exploration in the Chukchi Sea off the coast of Alaska. The decision means the Department of Interior will begin formal reviews of exploration plans in the region, which will include an environmental analysis.

The lease was tied in up the court system amid complaints about the extent of environmental vetting. A preliminary drilling campaign from Royal Dutch Shell off the Alaskan coast in 2012 was plagued by problems, including a grounded drilling rig, violations of air pollution limits, engine failures on a tow ship and an oil spill containment system damaged during testing.

Marissa Knodel, a campaigner for advocacy group Friends of the Earth, said the federal government appears "hell-bent" on opening the sensitive environment up for oil and gas exploration.

"It is unconscionable that the federal government is willing to risk the health and safety of the people and wildlife that live near and within the Chukchi Sea for Shell's reckless pursuit of oil," she said.

Shell had no public statement on the Interior Department's decision. The company devoted about $5 billion and more than eight years of work for its arctic oil exploration off Alaska's coast in the Chukchi and Beaufort seas.

Shell Chief Executive Ben van Beurden last month acknowledged there were "technical, fiscal, regulatory, political" and other issues that may interfere with frontier development in the arctic.

Susan Murray, deputy vice president for Pacific operations at conservationist group Oceana, said the Interior Department hasn't addressed all the risks associated with arctic exploration.

"Rather than once again committing to a risky, poorly justified decision to sell leases in the Chukchi Sea, the government should wipe the slate clean and start over," she said in a statement.

Interior Secretary Sally Jewell said arctic waters are an "important component" of the nation's energy strategy.