Native groups and environmentalists most fear a serious oil spill in the Chukchi. The MMS itself estimated in the environmental impact statement authorizing the lease sale there was a 40 percent chance of a spill of at least 1,000 barrels or more over the life of any single oil development project in the Chukchi.

“If oil spills under ice in the middle of January there is absolutely nothing they can do about it,” said Rick Steiner, an oil spill expert at the University of Alaska, Anchorage.

“There’s a large stretch of time when they would be producing oil and have no way of cleaning up a spill.”

A legal challenge to the validity of the MMS’s environmental impact statement is under way, and a similar suit temporarily halted Shell’s plans to drill in the Beaufort Sea last summer.

Drilling opponents are pessimistic about their chances of putting a stop to the rush into the Arctic.

“Maybe there can be something worked out, but at this time it really doesn’t look that way,” sa