The Transportation Department (DOT) has launched new inspections of rail cars carrying oil from the booming Bakken formation that underlies North Dakota and nearby regions.

The inspections that one official dubbed the “Bakken Blitz” have been in the works for months, according to the department.

The effort follows July’s deadly derailment in Canada of rail cars hauling Bakken crude that has focused fresh attention on oil transit risks.

“DOT has launched a joint inspection operation to verify that crude oil is being properly classified in accordance with federal regulations,” a spokesman for DOT’s Federal Railroad Administration (FRA) said in a statement.

“’Operation Classification’ primarily involves shipments from the Bakken and activities include unannounced spot inspections, data collection and sampling as well as verifying compliance with federal safety regulations. These activities are underway and taking place at strategic terminal and transloading locations that service crude oil,” spokesman Kevin Thompson said.