The remarkable productivity of the Bakken oil fields of North Dakota and the rush to bring Bakken crudes to refineries have somewhat overshadowed the risks associated with shipments.  Specifically, Bakken light crudes have exhibited higher flammability than more traditional heavy crude oil.  This necessitates proper characterization of the shipment to ensure that it is accurately classified and packaged.

That point is being emphasized by the Pipeline and Hazardous Materials Safety Administration (PHMSA) in a recent safety alert directed toward the general public, emergency responders, shippers, and carriers.  The advisory was prompted by recent derailments in North Dakota, Alabama, and Lac-Mégantic, Quebec, involving Bakken crude and the resulting fires.

According to the Federal Railroad Administration (FRA), industry statistics demonstrate that, in terms of rail originations, crude oil shipments are the fastest growing of all hazardous materials shipped by rail. In its Annual Report of Hazardous Materials Transported by Rail for 2012, the Association of American Railroads (AAR) indicates that the number of crude oil originations has increased by 443 percent since 2005.

Packing group

Any hazardous material offered for transportation must be characterized and assigned to the correct Packing Group (PG).  Crude petroleum is generally assigned to PG III based on the material’s flash point.  However, light, sweet crude oil, such as that coming from the Bakken region, has a different composition than traditional crude, including a higher gas content, and shipments should be assigned to PGs I or II.  These PGs mean that the material’s flash point is below 73 degrees Fahrenheit (°F), and for PG I materials, the boiling point is below 95°F.  “This means the materials pose significant fire risk if released from the package in an accident,” says PHMSA. 

Operation Classification

Concerns about shipments of Bakken crude and proper classification in general have led PHMSA and the FRA to launch a program called Operation Classification.  Under this initiative, inspectors conduct unannounced inspections and test crude oil samples to verify that offerers have properly classified and described materials in shipping papers. 

In the most recent advisory, PHMSA says it intends to expand the scope of testing under Operation Classification to measure gas content, corrosivity, toxicity, flammability, and “certain other characteristics” of Bakken crude, which should more clearly inform the proper characterization of the material.

PHMSA says it intends to share the results of these additional tests with parties as they become available.  However, PHMSA advisory also states that offerers should not delay completing their own tests while PHMSA collects additional information.

PHMSA advisory

Also, an FRA letter to the American Petroleum Institute , which discusses the proper classification of crude oil being shipped by rail