A Maine environmental group says a Canadian company is seeking to reverse the flow of a major trans-Canada oil pipeline, potentially bringing so-called tar sands oil to New England for export.

The company, Enbridge, applied to the Canadian government Friday for permission to reverse the direction of its “Line 9″ pipeline to carry “heavy crude” toward Montreal from western Canada, according to a release from the Natural Resources Council of Maine. Currently, pipelines carry crude from Portland northwest to Montreal, but if crude is flowing eastward, those pipelines could be reversed as well.

“Today’s application is clear evidence that oil companies are planning to send tar sands across eastern Canada and New England,” said Dylan Voorhees, clean energy director for the Natural Resources Council of Maine.

“Today we are calling on the U.S. State Department to require a full environmental review of any proposal to bring tar sands through ExxonMobil’s New England pipeline,” Voorhees said.

Environmentalists worry that a spill of tar sands oil would irreparably damage important environmental areas like the Sebago Lake watershed and Casco Bay. They also worry that converting the Canadian sandstone deposits into petroleum products would accelerate climate change because carbon emissions from the process are higher than from liquid petroleum.