Lawyers for environmental and native Alaska groups are asking a federal appeals court in San Francisco to block an oil company's plans for exploratory drilling near the Arctic National Wildlife Refuge.
Earlier this year, the federal Mineral Management Service approved Royal Dutch Shell's drilling plans in the Beaufort Sea off the northern coast of Alaska.
Environmental groups claim the agency granted drilling permits to Shell without considering the environmental impact of a large oil spill on whales, polar bears and other species.
In August, the 9th U.S. Circuit Court of Appeals temporarily blocked Shell's plans until the court could weigh arguments on whether to allow the drilling.