After three fiery accidents involving trains carrying crude oil out of North Dakota's Bakken Shale, regulators and industry officials are trying to figure out why the oil is exploding. Crude is flammable, but before being refined into products such as gasoline it is rarely implicated in explosions.
Yet earlier this week, when a BNSF Railway Co. train hauling 104 tank cars filled with Bakken crude struck another train, some of the cars exploded one after the other, releasing fireballs that blazed several stories above the frozen prairie. "Crude oil doesn't explode like that," said Matthew Goitia, chief executive of Peaker Energy Group LLC, a Houston company that is developing crude-by-rail terminals....Of course, there are nasty chemicals to blame for this!:
...The energy industry has been reluctant to discuss publicly what might be causing the problem. It is possible, experts say, that unusually large amounts of naturally occurring and highly flammable petroleum products such as propane and ethane are coming out of the ground with the Bakken crude. Last March, Tesoro Logistics LP reported the Bakken crude it was transporting by rail was increasingly volatile. The San Antonio company didn't respond to a request for comment.
Another possibility is that impurities are being introduced during hydraulic fracturing, or fracking. That process involves pumping chemicals or other additives along with water and sand into a well to free more fossil fuels. One such additive is hydrochloric acid, a highly caustic material, which federal investigators suspect could be corroding the inside of rail tank cars, weakening them.
Oil from fracked wells can also be laced with benzene and other volatile and highly flammable organic compounds.Laced! With benzene! What's this? The aromatics range of crude oil can be anywhere from 3 to 30%? Nuh-uh!
If I had to hazard a guess, I'd go with the first explanation, which is that crude that is fracked probably carries with it a higher percentage of trapped volatiles that are more flammable. I could be convinced that corrosion might play a role in this, but I'd be much likelier to believe that old/busted tank cars are being pressed into service inappropriately rather than an explanation about fracking fluid contamination. Interesting issue -- I'll try to keep an eye on this.