By Bill Holloway
A series of high profile derailments and explosions involving trains hauling oil, most notably in Lac Mégantic, Quebec, have prompted calls for improved rail safety and new guidelines governing the testing and transport of oil. Concerns center on train speeds and track conditions as well as the explosiveness of oil from North Dakota’s Bakken formation oil fields.
Whether derailments were due to high speeds—the apparent cause of the Lac Mégantic disaster—or poor track conditions, which were blamed for the oil train derailment and explosion in North Dakota last December, the higher than normal explosiveness of the oil combined with lax testing by railroads appears to be the reason for the massive explosions resulting from derailments.
Normally crude oil is not considered highly flammable. However, the light crude oil produced in North Dakota’s Bakken fields is much more volatile and explosive than most. According to a recent Reuters article on the flawed testing of North Dakota crude oil, the Reid Vapor Pressure of oil from the Bakken fields is often nearly twice that of popular imported crude oils, indicating a greater concentration of explosive gases such as butane, hexane, and propane.
Prior to shipping, railroads have historically tested oil for its boiling point and flashpoint, the temperature at which it will ignite from a spark. However, testing vapor pressure has not been standard practice. According to Harry Giles, managing principal of a liquid petroleum transport company, crude oil samples are often gathered in plastic two-liter bottles that allow flammable gasses to vaporize before they can be tested. Samples must be chilled and pressurized in order to preserve them for vapor pressure testing. This requires the use of more expensive specialized containers, known as floating piston cylinders, which can cost over $2,000 apiece.
While U.S. regulators issued a recent emergency order requiring companies to have tested their oil shipments in the “reasonable, recent past,” vapor pressure tests are still not required. Other measures to improve safety of rail shipments are the result of a voluntary agreement between USDOT and the American Association of Railroads. By April new braking technology will be used on oil tank trains to prevent pile-ups in the event of derailments. And by July, crude oil trains using model DOT-111 tank cars—the most common tank car for oil shipments—will abide by a 40-mph speed limit in urban areas. In the wake of the derailment and explosion in North Dakota, BNSF Railway has announced that it will purchase 5,000 new crude oil tank cars that will feature thicker tank walls, better pressure valves, and other safety features.
A recent policy brief by Susan Christopherson of Cornell University provides an overview of the risks associated with shipping oil by rail. She claims that as rail shipments of crude oil have increased by more than 35 fold since 2009, regulatory oversight has not kept up, and only about 1 percent of U.S. railroad infrastructure is inspected by the FRA each year. In addition, because power to regulate railroads is held solely by the FRA, state and local governments are largely powerless to regulate their activities.
Bill Holloway is a Transportation Policy Analyst at SSTI.
By Bill Holloway