Tar sand spilling from the Keystone SpillLine is not the same as the light sweet crude spilling from a tanker in the ocean. Tar sand is almost solid and has to be treated with toxic chemical solvents to get it diluted enough to be pumped through a pipeline and only under very high pressure. The pipeline reaches temperatures of 150 degrees or higher from the friction against the inner walls. In the summer of 2010, a pipeline near Marshall, Mich., operated by Enbridge Energy spewed 843,000 gallons of tar sands crude into the Kalamazoo River. More than a year later, 35 miles of the river remain closed, and estimates of the costs are at half a billion dollars and rising.
A tar sand spill is therefore not like any other oil spill because it puts the local fresh water supply at risk from the toxic chemical solvents. A spill of light sweet crude into the ocean does not put the fresh water supply at risk.
The "toxic chemicals" you refer to are no more toxic than the oil is itself. Most chemicals are made from oil, especially solvents.
Furthermore, the solvent they use to extract the oil is recycled. If they left it in the product, they would consume as much solvent as they amount of oil produced. So-called "tar sand crude" is no more toxic than any other crude. It just happens to be more viscous.
I was working in Battle Creek Michigan when the spill you referred to occurred. The river the oil spilled into runs right though the middle of town. All the local hotels filled up with clean up crews. You could smell the oil for a few days after the spill, but it wasn't long before you didn't notice a thing. I have no idea what it means for "35 miles of river to remain closed," other than the fact that the pipeline company is still engaged in cleanup operations. They are doing everything they can to return the entire length the spill to it's original condition. However, natural processes would return the stream to it's original condition in a few years anyway. Remember, we are talking about a small stream here, not a major river.
This spill was only a problem because the oil went into a waterway. If it had occurred on dry land, the damage would have been trivial. If anything this incident should serve only to indicate the increased danger of shipping oil by water way.