The Dec. 30 explosion of an oil unit train that caused the voluntary evacuation of Casselton, N.D. comes after a Nov. 1 explosion in Aliceville, Ala. that burned for a full week. The July explosion that leveled downtown Lac Mégantic, Quebec also killed 47 people. In each case, the oil originated from the Bakken shale formation in N.D. and Montana.
"Crude is flammable, but before being refined into products such as gasoline it is rarely implicated in explosions," write Russell Gold and Lynn Cook. Referring to the Casselton explosion, an energy industry executive added, "Crude oil doesn't explode like that."
Even before the latest accident, two government agencies—the Federal Railroad Administration (FRA) and the Pipeline and Hazardous Materials Safety Administration—launched a joint investigation they call the "Bakken Blitz" to better understand what impurities might be in the crude and whether it is being handled properly. The government wants to make sure hazardous liquids are labeled accurately and transported in appropriately sturdy tank cars.
"Recent derailments and resulting fires indicate that the type of crude oil being transported from the Bakken region may be more flammable than traditional heavy crude oil," stated a PHMSA official according to Platts on Jan. 2.
Gold and Cook point to two possible causes for the explosions. "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," they write.
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.
The FRA already "found during a spot inspection some (Bakken) crude oil that became combustible at a temperature so low it should have been placed in the most secure rail cars with additional safety features." Switching to the safest rail cars "might cost energy companies $1 billion or more, according to the American Petroleum Institute (the oil industry's main federal lobbying group), which opposes proposals to upgrade all existing tank cars too quickly."
The Wall Street Journal article, which may require a subscription to access, ends on that somber note, which would seem to confirm Monday's grim post, Oil-by-Rail a Pending Disaster for Cities, says Economist. [At least until all tank cars are upgraded to accommodate the more explosive crude from the Bakken field.]
UPDATE (1/8/2014) from Reuters: - "A Canadian National Railway train carrying propane and crude oil derailed and caught fire on Tuesday [about 7 p.m. local time] in northwest New Brunswick, Canada, the latest in a string of train accidents that have put the surging crude-by-rail business under heavy scrutiny."
The train began in Toronto although the origin of the crude oil is unknown at this time. A CBC news broadcast covered the fire.