Reporting from Seattle—

Federal authorities have approved an oil spill response plan that could allow drilling to commence this summer in the Beaufort Sea, the first major offshore drilling in the Arctic since the early 1990s.

Though Shell Alaska still needs several final permits, the oil spill plan has been the most debated aspect of the upcoming drilling program, with fears that cleaning up an offshore blowout in the turbulent, often icy seas of the Arctic could be a formidable challenge.

“We have conducted an exhaustive review of Shell’s response plan for the Beaufort Sea,” James A. Watson, director of the federal Bureau of Safety and Environmental Enforcement, said in a statement. “Our focus moving forward will be to hold Shell accountable and to follow up with exercises, reviews and inspections to ensure that all personnel and equipment are positioned and ready.”

Shell, which has spent nearly $4 billion and five years preparing to drill exploratory wells in the Beaufort and nearby Chukchi seas, said it hopes to begin drilling as early as July 10 and continue until just before the onset of ice in the fall. The program calls for halting operations during the late summer hunt for bowhead whales undertaken by local native Alaskans.

The oil spill response plan approved Wednesday is beefed up from an earlier plan, planning for a worst-case scenario three times bigger than what was studied before the Deepwater Horizon spill in the Gulf of Mexico sent planners back to the drawing boards.

The current plan requires Shell and its fleet of offshore oil response vessels to be ready to contain and clean up a discharge of up to 480,000 barrels of oil, representing a blowout of 16,000 barrels a day over a 30-day period. Such a spill would probably send oil pluming many miles offshore in a swath extending from just east of Prudhoe Bay to about 45 miles further east, at Brownlow Point on the edge of the Arctic National Wildlife Refuge, according to the document.

The plan suggests the likelihood of that happening is quite small: Shell is designing and prepositioning a containment device, similar to that which eventually halted the Deepwater Horizon blowout, that would theoretically be quickly clamped onto the well in the event that, as happened in the gulf, the built-in blowout preventer failed.

Federal officials say the chances of a blowout are much less likely at the substantially shallower depths and lower pressures of the Arctic.

But the plan does explore in some detail the scenario drilling opponents fear most: a spill at the end of the operations season in October, at the onset of the Arctic winter and the ice, darkness and powerful storms it brings.

The plan concedes that traditional mechanical means such as booms will become ineffective once freeze-up occurs and provides for “alternative response countermeasures” including in situ burning with helicopter-deployed torches and application of dispersants “when feasible and permitted.”

It suggests that icebreakers may still be able to open up leads to allow skimmers to access oil trapped next to or within heavier ice concentrations, and once oil is trapped under the ice, it can be tracked through the winter with the use of ground-penetrating radar, laser fluorosensors and other high-tech devices, the plan says.

While some work may be done atop coastal shorefast ice to remove oil trapped underneath, there is little likelihood of attacking oil under ice further out to sea, the plan concedes, acknowledging it will be “impractical and unsafe” to work from moving ice floes.

“They have all this high-tech equipment, and imagine trying to get it to work in the kind of conditions they have in an Arctic winter,” Chris Krenz, Arctic program manager for the conservation group Oceana, said in an interview. “Even to think we can track oil during the summertime, when there might be fog and other things, is a pretty big leap of faith, but to think we’d be able to track the oil under the ice in real-world conditions during the winter is just ludicrous — especially if it’s a major blowout.”

Drilling opponents are pointing to a still-uncontrolled gas leak near a Total platform in the North Sea off the coast of Scotland as an example of what can go wrong during offshore operations. Officials at the French energy company have said it could take six months to halt the release of gas.

“The gas spill in the North Sea and other recent disasters, including a recent natural gas blowout in Alaska, remind us that the risks are too great, particularly in places like the Arctic where the challenges are foreboding,” Alaska Wilderness League director Cindy Shogan said in a statement.

“We can only hope that President Obama shows the leadership he promised and refuses to bow to the demands of Big Oil by not granting Shell the final permits it needs to begin drilling in July,” she said.

The Obama administration, pursuing what the president has described as an “all-of-the-above” energy strategy, announced Wednesday it is also moving forward with studies of offshore oil development in the mid- and southern Atlantic Ocean. U.S. Interior Secretary Ken Salazar said the department will be accepting comments on a draft environmental impact statement looking at whether, and where, offshore leasing might be appropriate.

Alaskan officials have welcomed approval of offshore drilling as a means of keeping oil flowing through the trans-Alaska pipeline as the aging onshore fields on the North Slope continue to decline.

Shell officials also were celebratory.

“Today’s approval of our Beaufort Sea oil spill response plan, on the heels of the recent approval of our Chukchi Sea oil spill response plan, is another major milestone achieved. It further reinforces that Shell’s approach to Arctic exploration is aligned with the high standards the Department of Interior expects from an offshore leader and adds to our confidence that drilling will finally commence in the shallow waters off Alaska this summer,” spokeswoman Kelly op de Weegh said in a statement.

She said several additional approvals still are needed before drilling can commence, including letters of authorization from U.S. Fish and Wildlife Service, and authorization for incidental harassment of wildlife from the National Marine Fisheries Service. There still has been no ruling from theEnvironmental Protection Agency’s appeals board on an air permit issued for Shell’s Kulluk drilling unit. And the company still needs individual federal permits for each of the wells it proposes to drill this year.

http://www.latimes.com/news/nation/nationnow/la-na-nn-arctic-drilling-20120328,0,2904392.story