Oil drilling in the Arctic may need to slow down, now that polar bears, iconic symbols of global warming, are headed for protection under the US Endangered Species Act, experts said. US Interior Secretary Dirk Kempthorne this week added polar bears to the list of threatened animals under the act because their sea ice habitat is rapidly melting -- a move that comes just as the oil industry is pushing into offshore Arctic Alaska frontiers. Experts said the additional protections for the bears will reduce the chances oil companies will be allowed to drill in the Arctic National Wildlife Refuge, dimming hopes that the oil-rich wilderness would help the United States curb its dependence on energy imports. It could also mean new buffer zones in the Arctic to protect nursing mother bears and cubs from deafening seismic testing, revamped oil spill contingency plans and the delay of future lease sales for energy exploration, the experts said. "There will be additional permitting hoops that industry will have to go through," said Marilyn Crockett, executive director of the Alaska Oil and Gas Association. "These have the potential to slow projects down. But I think the big hurdle out there is the lawsuits that are likely to be filed." DENS IN ANWR Crockett said the listing was unfair because it places the burden for corrective actions on the oil and gas industry as well as Native subsistence hunters, even though neither of those groups apparently has caused the polar bears' problems. Environmentalists say the controls are needed anyway because of the increasing risk of spills as energy companies move into the Arctic offshore. "While that was true of terrestrial oil and gas activities of the past, offshore oil and gas is very different," Geoffrey York, director of the World Wildlife Fund's polar bear conservation program, said. He said government studies estimate a 30 percent chance of a large oil spill, if development procedes in the Chukchi Sea, off northwest Alaska. Deborah Williams, a former Clinton administration official who now heads Alaska Conservation Solutions, an environmental group, said a controversial proposal to open up the Arctic National Wildlife Refuge to oil companies could be swept off the table. "This listing supports the continued protection of the coastal plain of the Arctic National Wildlife Refuge," she said. "(The area) continues to have the highest concentration of polar bear denning sites. "No one can say right now with any certainty what the impacts of the listing decision will be. Much of this will ultimately be decided by the courts." Alaska Gov. Sarah Palin, however, said she hoped oil and gas activities will be able to continue without interference. "Alaska will have to continue its record of balancing responsible development of our nonrenewable resource while we're protecting that magnificent species of wildlife," she said While Palin said her administration would "work with the decision," she also held out the possibility of a state lawsuit disputing the listing. "Our attorney general will be reviewing the decision and determine whether the decision was reached properly, or whether it deserves a closer look," she said. One company active in Arctic Alaska said it was confident it can develop energy sources without disturbing polar bears. Shell Oil, which in February dropped $2.1 billion in a lease sale for exploration rights in the Chukchi Sea, and in 2005 spent $44 million for leases in the Beaufort Sea, said it already takes special care to keep polar bears safe. "Shell's polar bear policy currently meets or exceeds all existing regulatory requirements, including reporting, training and avoidance measures. In the future, as new regulations take shape, Shell with work with regulatory agencies and stakeholders to determine if additional mitigation measures are needed," the company said in a statement. (Editing by Walter Bagley) Story by Yereth Rosen REUTERS NEWS SERVICE