Some background: Tar sands oil contains — among other heavy metals, neurotoxins, and carcinogens — an average of 11 times more sulfur and nickel, six times more nitrogen, and five times more lead than conventional crude oil (.pdf source here). Refining it emits three times as much global warming pollution as conventional oil (here), and the massive network of refineries along the Ship Channel is one of the only places in North America with the industrial capacity to create fuel from the tarry sludge of bitumen flowing from Alberta, Canada. Consequently, it is already one of the worst public health zones in the nation.
The proposed Keystone XL pipeline would bring upwards of 700,000 barrels of oil per day, and potentially 900,000 once the pipeline is completed, to be refined in Houston and Port Arthur. That represents about 35% of the capacity of the targeted refineries. Given that this oil is a lower quality crude with higher levels of toxic contaminants than usual, the risk of extremely grave consequences is unacceptably high — for Houston’s air quality, the health of its citizens and the repercussions from the federal government for continually failing to meet clean air standards.
Well worth your time to read.