Nearly a dozen shipments of oil coming out of North Dakota were mislabeled by oil producers, potentially creating hazardous risks, federal regulators have found.

The Pipeline and Hazardous Materials Safety Administration, which oversees the transportation of petroleum, said samples taken from 11 out of 18 truck shipments en route to rail loading stations were misclassified.

The companies responsible for the errors were Hess Corp., Whiting Oil and Gas Corp., and Marathon Oil Co.

The three businesses face fines totaling $93,000.

Incorrectly classifying oil shipments can result in firefighters and other emergency personnel taking the wrong action in response to an accident.

Some of the oil tested by regulators was classified as “packing group III”—for which no security plan is required—when it should have been listed as “packing group II.” Similarly, some oil was classified as “packing group II,” when it should have “packing group I”—the most dangerous category.

Federal regulations mandate that shippers have a security plan in place for packing groups I and II.

The misclassification of oil may have played a role in the horrific explosion and fire that leveled much of the small Canadian town of Lac-Megantic in Quebec last summer. The accident occurred after a train loaded with North Dakota oil derailed—oil that was mislabeled as “packing group III.”

The catastrophe killed 47 people and destroyed 30 buildings.

Last month, accident investigators in the U.S. and Canada issued a warning that train accidents involving crude oil cargo can result in a “major loss of life.” They urged better efforts to ensure proper classification of all such hazardous cargo and avoidance of travel through populated areas.

-Noel Brinkerhoff

To Learn More:

Feds: Oil from Dakota Fields Improperly Classified (by Joan Lowy, Associated Press)

More Oil Spilled from Trains Last Year than in Previous 37 Years Combined (by Noel Brinkerhoff, AllGov)