Environmentalists: Walrus Population at Risk in Arctic

Green groups urged the U.S. Department of Interior on Tuesday to revoke the agency's conditional approval of Royal Dutch Shell's 2015 Arctic oil exploration plan, saying it runs counter to established protections for walruses.

A 2013 rule implemented by the Fish and Wildlife Service, a bureau of the Interior Department, prevents energy companies from exploring for oil simultaneously at wells in the Chukchi Sea off Alaska that are within 15 miles (24 km) of each other.

The rule is meant to protect walrus populations that are sensitive to the noise and disruption of drilling in their habitat.

But Shell's exploration plan for the Chukchi, which the Interior Department conditionally approved in May, calls for simultaneous drilling, and no two of its wells there are more than 15 miles apart, said a letter to Interior Secretary Sally Jewell sent on Tuesday by 10 environmental groups.

"There does not appear to be any way that the federal government can allow Shell to proceed as the company has planned," said Michael LeVine, a lawyer for Oceana, one of the groups that signed the letter.

Shell spokesman Curtis Smith said the company continues to consult with regulators on the matter. Shell has spent $7 billion exploring the Arctic for reserves off Alaska, but oil production is not expected to begin for 10 to 15 years.

The company is hoping to return to the Arctic in July for the first time since its mishap-plagued 2012 drilling season. But the plan has become the target of a major campaign by environmentalists opposed to oil and gas exploration in the Arctic.

The letter - the latest move by groups to short-circuit Shells' plans - asks Jewell, "to take immediate action to address this basic deficiency in Shell's drilling plan and permit applications, protect the Pacific walrus, and ensure agency decisions resulting from the review of Shell's drilling proposal are defensible and lawful."

The Interior Department did not immediately return requests for comment on the letter, which was also signed by the Sierra Club and Greenpeace, among other groups.

Reporting by Timothy Gardner