PORTLAND, Maine (AP) â¿¿ An environmental group says Canadian pipeline company Enbridge has asked its government for permission to reverse the flow on a pipeline, bringing oil from western Canada to Montreal. The Natural Resources Council of Maine says the move would open the door to bringing tars sands oil to New England for export. Currently, pipelines carry crude from Portland to Montreal, but the council thinks it could be reversed. Dylan Voorhees, the council's clean energy director, said he's calling on the State Department to ensure a full review of any attempt to bring the oil into Maine. Opponents warn that the heavy, acidic crude oil could corrode metal pipe, leading to a spill. They also argue the tar sands oil is dirtier than most and will further harm the air.