The researchers at the University of Auburn have published the following analysis:
"Tar sand produces 17% more greenhouse gases than traditional crude oil (NPR). The air quality has become life threatening, and residents are forced to breathe in dangerous emissions. Children in surrounding the new pipeline are 56% more likely to develop leukemia versus children that live ten miles away."
"If a leak does occur once the pipe is built, residents will be at risk of toxic exposure. In every instance of a tar sand leak in populated areas, toxic chemical exposure through respiration has occurred. Toxic chemical exposure can lead to migraines, painful rashes, breathing complications, nausea, chemical sensitivities, and exacerbated cancer activity (Tar Sands Blockade). Tar sand sinks into water, making the cleanup extraordinarily expensive. When tar sand is exposed to air, the harmful chemicals that are added as diluents evaporate into the air forming heavy toxic clouds close to ground level."
http://cla.auburn.edu/ces/energy/oil-pipelines-and-spills/