They alleged oil spills in Alaska’s Beaufort and Chukchi seas would be difficult to clean up, and therefore endangered wildlife and the Arctic ecosystem.

Environmental groups called the court decision a setback, but vowed to keep the pressure on Arctic drillers and federal regulators.

“Last summer when the veneer of empty promises and fanciful reassurances was peeled back, the dirty reality of Arctic oil drilling appeared: harsh weather, equipment failures, human error and legal violations all characterized Shell’s 2012 drilling season,” Rebecca Noblin, the Center for Biological Diversity’s Alaska director, said in a statement. “Despite this court’s decision, we will continue to do everything we can to protect the Arctic from unsafe drilling.”

Shell announced in February that it would pause its U.S. Arctic drilling operations after a series of fits and starts — largely equipment-related blunders — took the oil giant off course.

The company agreed to work with Interior to develop a safer drilling regime with an eye toward returning to the Beaufort and Chukchi seas, where Shell has already drilled preparatory wells, in the future.

Shell’s mishaps also spurred a comprehensive review by Interior that was designed to overhaul federal coordination on Arctic drilling.

— This story was updated at 9:43 a.m.