Canada’s energy authority gave conditional approval earlier this month to the Northern Gateway Pipeline project, which would run through British Columbia and would send hundreds more crude oil supertankers along high-traffic shipping lanes in Alaska waters.

That means the Aleutian Islands will have to prepare for a higher risk of spills and accidents.

The proposed pipeline stretches from Alberta, Canada, out to Kitimat, British Columbia, on the coast. It would carry 520,000 barrels of diluted oil sands bitumen a day.

Canada’s National Energy Board said in mid-December that with some extra safety measures, they’d recommend that the government give the okay to build the pipeline.

The Energy Board said in its report that tankers ought to have escort tugs as they traverse the narrow channels off British Columbia and head in toward the pipeline. But the board’s recommendations don’t cover what happens to tankers when they’re farther out to sea -- like in the Aleutian Islands.

"To see this group of vessels and the increased number of vessels that would be going through Unimak Pass, the Bering Sea, even as they make their way out of Southeast Alaska, should have some cause for concern both for the United States and the state of Alaska," says Leslie Pearson, project manager for the Aleutian Islands Risk Assessment.

The AIRA's last vessel traffic study said that 11 crude oil tankers passed through the chain in 2008. If the new pipeline is built, Pearson says that number would spike dramatically -- to as many as 700 tankers a year.

Big tankers have had deadly accidents in the Aleutians in the past, like when the Selendang Ayu grounded in Unalaska in 2004. The ship had drifted and broken in two after losing power in Unimak Pass. It spilled about 350,000 gallons of fuel and some of its soybean cargo.

Unimak Pass is a vital cut-through in the Aleutian chain. Even now, Pearson says it can be a choke point for vessel traffic. 

"It’s quite wide, but if you're in a tug and barge, and you’ve got a big tank ship coming down on you, it can get to be a little nerve-wracking," she says. "Unimak Pass is like an I-5 corridor through the Bering Sea and then out to Asia on the west side. And it’s going to be something to keep an eye on for the times to come."

Gary Folley of the Alaska Department of Environmental Conservation is helping with that. He manages the state’s spill prevention and response program, and he’s also part of the AIRA.

Folley says the issue isn’t whether Unimak Pass can handle an increase in tanker traffic, but how it’s going to handle it safely.

"I don’t think there’s an upper limit. It’s just as traffic increases, then so do the risks of having any kind of accident," he says. "The greatest threat we have is for drift groundings, where vessels lose power or lose steerage or whatever, and gradually drift and ground."

The Selendang Ayu was 100 miles from Unalaska when it lost power. Leslie Pearson says some tankers travel as close as five to 20 miles off-shore in the Aleutians.

That gives them a dangerously short window to make repairs or be towed to safety before they run aground. The AIRA is looking at trying to route tankers further out from shore, to give them more time to make corrections or be rescued.

In the event of a spill, the Northern Gateway tankers’ cargo would also be a concern. Folley says oil sands bitumen is heavier than regular oil, so it sinks faster, making it harder to clean up.

And he says any kind of spill in the Aleutians is a challenge -- even under the best circumstances. And that’s probably not going to change.

"You look at the size of Alaska and the remoteness of the Aleutian Islands -- to place response depots through all the entirety of the Aleutian Islands then becomes extremely expensive," he says.

That’s why he says spill prevention is key.

But there’s another problem -- Leslie Pearson says the Northern Gateway tankers wouldn’t stop at an American port on their way to Canada from, say, Asia. That means U.S. and Alaska regulations, like those aimed at spill prevention, don’t apply.

"They’re exempt from having a vessel response plan, being members of an oil spill response cooperative -- they don’t even have to meet the salvage and marine firefighting regulations for the United States, either," she says.

Pearson hopes they could design some kind of safety program for Unimak Pass that foreign vessels would want to buy into.

"It’s just going to be an interesting time to see how perhaps the U.S. government and Canadian government maybe talk through some of these issues and look at the downstream effect from large projects like this," she says.

So far, she says there hasn’t been much consultation. Pearson is focused on the next round of risk assessment data, which is due out in January. And she says the team plans to make new recommendations on emergency management in the Aleutians by June.

Gary Folley hopes all that will help them prepare for what he says is an inevitable upswing in vessel traffic -- whether or not the Northern Gateway Pipeline gets built.

"You know, it’s just a fact of life that the shortest distance between two points, between the West Coast and Asia, happens to run through the Aleutian Islands," he says. "Traffic is likely to increase, and this is just one of the ways that it could."

But nothing’s for sure until the pipeline gets final approval -- and that’s a big if. Government leaders in Canada are facing a lot of opposition. They’re expected to make a decision within six months.