How Little We Know About Heavy Tar Sands Oil

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http://www.thenation.com/blog/173633/how-little-we-know-about-heavy-tar-sands-oil

When the Exxon Pegasus pipeline ruptured Friday in Mayflower, Arkansas, tens of thousands of gallons of diluted bitumen were sent forth into a residential neighborhood, and 22 homes had to be evacuated. Since this is the same sort of oil that would be carried by the Keystone XL pipeline, were it to be built, the Arkansas spill is appropriately spurring a conversation about safety. Is Keystone also going to lead to more spills? (There have been twelve on the completed portions of the pipeline already.) And how dangerous is this stuff spilling all over the ground?

But this conversation must start with a simple fact: There are too many known unknowns about diluted bitumen. We don't know exactly what's in it, and the government hasn't fully studied how safe it is to transport.

Bitumen is a form of petroleum that occurs in a solid, or semi-solid, state: It can be sludgy or even be brittle, like rocks. That’s what is buried deep in the Canadian oil sands. In order to transport this bitumen through thousands of miles of pipelines so that it can be refined, it has to first be diluted, so it flows like a liquid.

That diluent is usually a natural gas liquid—but we don’t know for certain what it is. The industry considers its diluent formulas proprietary information and won’t share it with regulators.