(4 pm. – promoted by ek hornbeck)
On Friday, a 20 inch pipeline carrying Canadian heavy crude oil ruptured in Arkansas flooding the town of Mayflower with 84,000 gallons of the world’s dirtiest oil. The pipeline was carrying Canadian Wabasca Heavy crude, a heavy bitumen crude diluted with lighter liquids to allow it to flow through pipelines. the oil is produced in the Athabasca region, where the oil sands are located.
According to Exxon, the Pegasus pipeline carries 90,000 barrels of oil per day from Pakota, Illinois, to Nederland, Texas. The proposed Keystone XL pipeline will carry 800,000 barrels per day from Canada the Gulf Coast refining hub. This is the second spill of Canadian oil in the past week. A tanker train derailed in Minnesota spilling 15,000 gallons of oil.
This has prompted critics of Keystone XL, to point out the dangers of the pipeline and urge the president to reject the permit. “This latest pipeline incident is a troubling reminder that oil companies still have not proven that they can safely transport Canadian tar sands oil across the United States without creating risks to our citizens and our environment,” said Rep. Edward J. Markey (D-MA), the ranking Democrat on the House Natural Resources Committee.
I’m no engineer, but from what I understand, when a section of pipe ruptures, the quantity of oil that can spill is as large as the pipe is thick and long until you reach the nearest shutoff valve. It also depends on how fast the pipeline operators notice the spill, shut off the flow and close the leak.
In 2009, Exxon modified the capacity of the Pegasus pipeline, increasing the capacity to transport Canadian tar sands oil by 50 percent, or about 30,000 barrels per day. In a 2012 report, Bloomberg News reported the pipeline daily capacity to be 96,000 barrels of oil per day.
Tar sands oil is the most toxic fossil fuel on the planet, that leaves in its wake scarred landscapes, a web of pipelines, and polluting refineries.
This morning on Democracy Now, Amy Goodman spoke with environmental activist Bill McKibben of 350.org about the spill.
What makes bitumen different from regular or conventional oil?
Conventional crude oil is a liquid that can be pumped from underground deposits. It is then shipped by pipeline to refineries where it’s processed into gasoline, diesel and other fuels.
Bitumen is too thick to be pumped from the ground or through pipelines. Instead, the heavy tar-like substance must be mined or extracted by injecting steam into the ground. The extracted bitumen has the consistency of peanut butter and requires extra processing before it can be delivered to a refinery.
There are two ways to process the bitumen.
Some tar sands producers use on-site upgrading facilities to turn the bitumen into synthetic crude, which is similar to conventional crude oil. Other producers dilute the bitumen using either conventional light crude or a cocktail of natural gas liquids.
The resulting diluted bitumen, or dilbit, has the consistency of conventional crude and can be pumped through pipelines. [..]
If dilbit has the consistency of regular crude, why did it sink during the Marshall spill?
The dilbit that spilled in Marshall was composed of 70 percent bitumen and 30 percent diluents. Although the dilbit initially floated on water after pipeline 6B split open, it soon began separating into its different components.
Most of the diluents evaporated into the atmosphere, leaving behind the heavy bitumen, which sank under water.
According to documents  released by the National Transportation Safety Board-a federal agency that is investigating the spill-it took nine days for most of the diluents to evaporate or dissolve into the water.
Can conventional crude oil also sink in water?
Yes, but to a much smaller extent.
Every type of crude oil is made up of hundreds of different chemicals, ranging from light, volatile compounds that easily evaporate to heavy compounds that will sink.
The vast majority of the chemicals found in conventional oil are in the middle of the pack-light enough to float but too heavy to gas off into the atmosphere.
Dilbit has very few of these mid-range compounds: instead, the chemicals tend to be either very light (the diluents) or very heavy (the bitumen).
Because bitumen makes up 50 to 70 percent of the composition of dilbit, at least 50 percent of the compounds in dilbit are likely to sink in water, compared with less than 10 percent for most conventional crude oils. [..]
Why has it been so hard to clean up submerged oil in the Kalamazoo?
Existing cleanup procedures and equipment are designed to capture floating oil. Because the Marshall accident was the first major spill of dilbit in U.S. waters, cleanup experts at the scene were unprepared for the challenge of submerged oil. [..]
Once cleanup crews locate submerged oil, it’s hard to remove it without destroying the riverbed. Cleanup workers in Marshall were forced to improvise less invasive procedures that balanced oil cleanup with protecting the ecosystem.
On July 16, 2010, just nine days before the Marshall accident, the EPA warned that the proprietary nature of the diluents found in dilbit could complicate cleanup efforts. The agency was commenting  on the State Department’s Draft Environmental Impact Statement (EIS) of the Keystone XL, a proposed pipeline that would carry Canadian dilbit across six U.S. states and the critically-important Ogallala aquifer.