It's hard to predict how bitumen from the Alberta oil fields will behave in the event of a spill, making it difficult to understand the risks, says a U.S. government emergency response official.
Gary Shigenaka, a marine biologist for the National Oceanic and Atmospheric Administration's emergency response division, said the U.S. organization has many questions about the pipelines proposed through British Columbia and the product that would flow through them.
"As we tried to understand all of the facts about this product, it was very confusing," Shigenaka told those attending the Salish Sea Ecosystem conference this week in Seattle.
"We're going to be worried about how it's behaving."
Even figuring out if the diluted bitumen, or dilbit, would sink or float was a complicated process, he said.
"Does it float? Yes it does. When it's mixed and when they put it in a pipeline it floats," he said. "But it can also sink. It can sink if you mix it with sediment, so if you spill it in the environment, it mixes with sediment ... then it can sink. So, there's your answer."
Canada's pipeline plans are a hot topic among scientists and conservation groups at the conference in Seattle. Those pipelines include Enbridge's (TSX:ENB) Northern Gateway and Kinder Morgan's Trans Mountain proposal, as well as the Keystone XL line into the U.S.
Washington state also has several oil refinery and export proposals of its own that would add vessel traffic to the Salish Sea, Shigenaka said, most from the Bakken oil fields in North Dakota.
The "poster child" for a fresh water oil spill remains the 2010 Enbridge pipeline rupture in the Kalamazoo River in Michigan, Shigenaka said. Enbridge is the company behind the Northern Gateway project, he noted.
"There were a number of people who testified in Canadian hearings that it can't sink, it absolutely can't sink, then there were studies that came out that said, well, it can sink," Shigenaka said.
"It sank in Michigan during the Kalamazoo spill.
"They're still working on that spill from 2010 .... They're hoping to have that cleaned up this fall. So, four years later they're still cleaning up."
There are also concerns about the toxicity of the diluent mixed into the "peanut butter-like" bitumen. The recipe is proprietary, so his agency doesn't know what exactly is in it, he said.
"We're sort of wary about occupational exposure to that diluent portion of the product."
Eric De Place, policy director for the Sightline Institute, a Seattle-based sustainability think-tank, said Oregon, Washington state and B.C. are facing a huge increase in oil traffic.
Debate in the U.S. has focused on the Keystone XL pipeline, but that project would carry less than the two pipelines proposed through British Columbia to the Salish Sea, De Place said.
The Northern Gateway would carry up to 525,000 barrels per day to a marine terminal in Kitimat, on the north coast of B.C. The expanded Trans Mountain pipeline through the B.C. Interior to Metro Vancouver would almost triple capacity, from 300,000 barrels a day now to 890,000.
"It's a huge, huge, deal," De Place told about 150 people at the conference.
"When we are having fossil fuel debates in Washington state or B.C. or Oregon, we are having debates that have genuinely global significance. There is no place, I would argue, in the world — except possibly the Gulf Coast — where we have this much responsibility on our hands and where we have this much threat."