The acknowledgement appears to directly contradict some claims made by Enbridge earlier this year, in which the company was promoting a page on its website claiming that “crude oils, including diluted bitumen,” float in water.
The note came as part of a 51-page document with proposed changes to State’s March draft environmental review of the Keystone XL pipeline.
“If oil does remain on the water surface for a sufficient time, without being cleaned up, there is the potential for some oil to sink,” TransCanada wrote to State in its comments on the department’s thousand-page analysis of the pipeline.
Enbridge, meanwhile, had said during the proposed Northern Gateway pipeline hearings that critics who claimed that tar sands bitumen could sink were falsely informed.
Former Exxon Mobil scientist Alan Maki stated that “it is an immutable fact of physics that they will float” in his February testimony before Canada’s National Energy Board (NEB). It referenced an industry-backed study which claimed that in a controlled lab environment, bitumen floats when placed in water.
Tweets from @NorthernGateway in February
The company since backed away from its initial claim, noting that various factors could be involved, but updated its site and tweeted to a group of scientists a group of conservationists and scientists:
“We’ve not claimed bitumen floats. We’ve described the conditions necessary for oil to sink and given evidence that dilbit floats.”
Inside Climate reported that although the lab study found that bitumen floats, the oil sunk when a million gallons of the diluted bitumen was spilled in Michigan’s Kalamazoo River in 2010.