Shell still must obtain permits from the Environmental Protection Agency for wastewater discharge and from the Interior Department’s Bureau of Safety and Environmental Enforcement to drill each specific well. The company must also demonstrate that its well-capping technology can work in the harsh conditions of the Arctic, and its drilling program must survive any court challenges.

Opponents said that Shell and the Obama administration had not fully absorbed the lessons of the 2010 Deepwater Horizon blowout and oil spill in the Gulf of Mexico, which killed 11 rig workers and spilled millions of gallons of crude into the gulf.

“This decision is premature,” said Marilyn Heiman, director of the Arctic program at the Pew Environment Group. “We need an additional two or three years of study to get the science right, to ensure proper monitoring and to protect wildlife.”

Ms. Heiman added, “They still don’t have standards for the Arctic, which is very different from the temperate waters of the gulf — the ice, the wind, the darkness. We think there are major gaps in this plan, and they need to take more time.”

Interior Department officials insisted that they had conducted an extensive scientific inquiry before moving ahead with the spill response plan. They also said this work would continue before and after Shell was allowed out on the water and that officials would conduct several spill response drills before any drilling began.

They have also shortened the season that Shell will be allowed to operate offshore to ensure that it has shut down operations and has time to take any remedial actions before ice forms in the Chukchi.

“This decision has been based on our new standards and our commitment to ensure the highest standard of safety and environmental preparedness in the world and our commitment to bringing science to all our activities in the Arctic,” said David J. Hayes, the Interior deputy secretary who is coordinating the Arctic offshore drilling policy.