The US Interior Department's Bureau of Safety and Environmental Enforcement (BSEE) has conditionally granted Royal Dutch Shell two final permits for exploration in the Chukchi Sea off Alaska. Sea ice limits exploration to between the months of July until October.

Environmental groups like Greenpeace USA have criticized Shell's drilling plans in the Arctic, which is not only home to sensitive populations of whales, walrus and polar bears but also to a large indigenous population, which would suffer from large-scale drilling.

They also argue that arctic offshore drilling is too risky in a fragile environment that has a lot of sea ice and experiences brutal storms.

The BSEE made the permits issued on Wednesday conditional on securing emergency equipment to contain a potential blown-out well being deployable within 24 hours. Only then can Shell start drilling.

"Without the required well control system in place, Shell will not be allowed to drill into oil-bearing zones," BSEE Director Brian Salemo said.

Shell found some weeks ago that the Fennica icebreaker that has the required equipment had a meter-long gash in it. The vessel was sent to Portland, Oregon for repairs last week but making the repairs and sending it back could take several weeks.

"Once we have determined the area is clear of sea ice, support vessels are in place, and the Polar Pioneer (rig) is safely anchored over the well site, drilling will begin," Shell spokeswoman Kelly op de Weegh said on Wednesday.

Until the emergency equipment is in place, Shell can only drill the top sections of wells.

"Without question, activities conducted offshore Alaska must be held to the highest safety, environmental protection and emergency response standards," BSEE's Salerno said.

The executive director of the Alaska Wilderness League, Cindy Shogan, called it the wrong choice: "This decision puts the fate of the fragile Arctic Ocean, and our climate future, in the hands of Shell Oil," she said in a statement.

jm/kms (AP, Reuters)