Maine environmental groups sounded an alarm Thursday about the possible impacts here of a Canadian energy company’s application to reverse the flow of a pipeline and move heavy crude oil from the western provinces to Montreal.

The groups said the application by Enbridge signals that the company plans to bring tar sands oil into Maine, through a pipeline that runs from Montreal to the South Portland waterfront.

The flow of oil in that line would have to be reversed also, as it now moves oil from Maine to Canada.

The Calgary, Alberta, company filed an application Wednesday with Canada’s National Energy Board asking for approval of three requests: a flow reversal of the company’s “Line 9” pipeline from Westover to Montreal, to enable the pipeline to carry oil from west to east; permission to transport heavy crude from western Canada; and an increase in the flow of the pipeline by 25 percent, to 300,000 barrels per day.

The petition to the Canadian energy board, an independent regulatory agency created by the government in 1955, is the most recent in a series of steps to streamline the flow of crude oil — both lighter crude and heavy tar sands — from Western Canada to Montreal.

The application does not include a request to transport past Montreal, said Graham White, spokesman for Enbridge.

“The focus of the application is the Montreal refineries,” White said in a phone interview Friday. “There is no proposal or plans to go past Montreal.”

Further, there are no projects or plans to work with the Portland Pipeline Corp. to carry tar sands from western Canada across Maine, he said.

Rather, the company “is equipping the line to carry processed and upgraded” product within Canada.

Only “a very small proportion” of the crude oil will be heavier products, White said.

The Natural Resources Council of Maine in Augusta and Environment Maine in Portland challenged the intent of the Enbridge application.

Dylan Vorhees, clean energy director for the council, called it “probably the most significant piece” of the tar sands pipeline development to date, and a clear indication that the company has its eye on a Maine tar sands pipeline.

“Enbridge has said that they want to bring tar sands to Portland,” Vorhees said.

“Absolutely” that is their plan. “This is as real as it gets for Maine.”

If Enbridge does transport tar sands through Maine, Vorhees said, any proposal to reverse the pipeline flow should be subjected to a close environmental review because tar sands “is a different enough substance” to require additional scrutiny.

Tar sands crude “is halfway between oil and coal … a sticky, rocky, sandy, oil substance (that) is dug out of the ground,” Vorhees said.

“It’s impossible to send through a pipeline (unless) diluted with a really nasty set of chemicals.”

It is more corrosive and more acidic than conventional crude, and it is pumped at higher temperatures and pressures, which makes it a greater threat to the environment and public health, he said.

A 2010 leak in an Enbridge pipeline near Marshall, Mich., dumped a million gallons of heavy crude oil into a creek that flows into the Kalamazoo River.

Fifty households were evacuated and about 100 more were advised not to drink their water. Cleanup costs exceeded $700 million.

That track record is part of the reason why concerned towns and residents in Maine will pursue other avenues to stop tar sands from crossing the border, Vorhees said. Some, no doubt, will choose litigation as a way to thwart further tar sands transport, Vorhees said, and already several towns — including Bethel, Windham and Casco — are pursing the “power of a town resolution” to call for the permit review in the U.S. or outright community opposition to the pipeline.

The Enbridge “application is a wake-up call that we are at risk from a pipeline that would bring dirty tar sands to our doorstep,” said Environment Maine Director Emily Figdor in a news release following the announcement of Enbridge’s request.

Vorhees said the council is circulating a petition opposing the pipeline here, and it already has been signed by about 1,000 people.

He said if tar sands crude was transported through a Maine pipeline and leaked, “there could be implications for drinking water,” because the pipeline passes near Sebago Lake, the water source for the Portland Water District.

Ted O’Meara, spokesman for the Portland Pipeline Co., which operates the Montreal-to-South Portland pipeline, said there is no plan to reverse the flow of oil in Maine.

“There’s no project right now,” he said. “There’s no plan to do it now. There’s no project.”

A proposal that examined the potential for a Montreal-to-South Portland flow “was talked about a few years ago, and shelved,” he said.

O’Meara would not rule out the possibility that the plan could be studied anew, but he said no plan would be put in place and sprung on Mainers unexpectedly.

“We’ve been a good neighbor for a lot of years,” he said, adding that the company was committed to maintaining that relationship with Portland and the rest of the state.

Staff Writer North Cairn can be contacted at 791-6325 or at:

ncairn@pressherald.com