By DAN JOLINGANCHORAGE, Alaska (AP) â¿¿ The grounding of a petroleum drilling ship on a remote Alaska island has refueled the debate over oil exploration in the U.S. Arctic Ocean, where critics for years have said the conditions are too harsh and the stakes too high to allow dangerous industrial development. The drilling sites are 1,000 miles from Coast Guard resources, and environmentalists argue offshore drilling in the Arctic's fragile ecosystem is too risky. So when a Royal Dutch Shell PLC ship went aground on New Year's Eve on an uninhabited island in the Gulf of Alaska, they pounced â¿¿ saying the incident foreshadowed what will happen north of the Bering Strait if drilling is allowed. For oil giant Shell, which leads the way in drilling in the frontier waters of the U.S Arctic, a spokesman said the grounding will be a learning experience in the company's yearslong effort to draw oil from beneath the ocean floor, which it maintains it can do safely. Though no wells exist there yet, Shell has invested billions of dollars gearing up for drilling in the Beaufort and the Chukchi seas, off Alaska's north and northwest coast. The potential bounty is high: The U.S. Geological Survey estimates 26.6 billion barrels of recoverable oil and 130 trillion cubic feet of natural gas exist below Arctic waters. Environmentalists note the Beaufort and the Chukchi seas are some of the wildest and most remote ecosystems on the planet. They also are among the most fragile, supporting polar bears, the ice seals they feed on, walrus, endangered whales and other marine mammals that Alaska Natives depend on for their subsistence culture. "The Arctic is just far different than the Gulf of Alaska or even other places on earth," said Marilyn Heiman, U.S. Arctic director for the Pew Environment Group.