In the latest sign that oil exploration could begin in the U.S. Arctic this summer, the Interior Department's Bureau of Safety and Environmental Enforcement today approved the spill response plan submitted by Royal Dutch Shell PLC for oil development in Alaska's Chukchi Sea.

In backing Shell's plan, Interior also announced that regulators will work with industry and research institutions to compile information on the ecologically sensitive and culturally important areas in the region.

In a briefing with reporters, Interior Deputy Secretary David Hayes said that throughout the exploration project, the Coast Guard will have on-sea resources and land-side support available at the drilling sight. A Bureau of Safety and Environmental Enforcement inspector, with the power to shut down the project in an emergency, will be on the rig throughout the drilling season, Hayes said.

Under the plan outlined by Interior, Shell would be required to shut down oil exploration 38 days before the expected onset of ice formation in the Chukchi to give the company enough time to shut down the well and clean up the oil before the ice set in. The company also has agreed to have oil spill containment equipment and a capping stack on site, as well as facilities to a drill relief well if a spill were to occur.

In approving the oil spill response plan, Interior Secretary Ken Salazar said in a statement that the federal government is "taking a cautious approach" and building on the lessons learned from the 2010 Deepwater Horizon accident on allowing drilling in the Arctic.

"Alaska's energy resources -- onshore and offshore, conventional and renewable -- hold great promise and economic opportunity for the people of Alaska and across the nation," Salazar said. "In the Arctic frontier, cautious exploration -- under the strongest oversight, safety requirements, and emergency response plans ever established -- can help us expand our understanding of the area and its resources, and support our goal of continuing to increase safe and responsible domestic oil and gas production."

But environmental groups are not convinced the federal government is doing enough to protect Alaska's wildlife and indigenous populations. In a statement, Ocean Conservancy's Arctic program director Andrew Hartsig described the announcement as "disappointing."

"Earlier this week, an exploration well on the North Slope suffered a blowout -- and crews are still working to regain control," he said. "Despite the Interior Department's optimism, Shell's oil spill response plan does not ensure an effective response if a blowout occurred while drilling for oil 70 miles offshore in the Chukchi Sea."

In early February, a group of 573 scientists sent a letter to President Obama asking him to stop offshore drilling in Alaska until experts can study the proposed oil development's impacts on sensitive Arctic ecosystems and native subsistence activities.

Shell has already received several other federal permits in its effort to begin oil exploration this summer in the Chukchi and Beaufort seas, but hurdles remain.

Together, the Beaufort and Chukchi seas could hold as much as 27 billion barrels of oil and 132 trillion cubic feet of natural gas, according to U.S. Geological Survey estimates. That is more than the 17 billion barrels of oil that has flowed out of Alaska's Prudhoe Bay oil fields over the past 30 years.