New information from the U.S. Department of Transportation shows authorities were worried prior the Lac-Mégantic disaster  about the transport of oil from North Dakota on trains.

Federal authorities in the United States are now stepping up inspections of crude oil coming out of the Bakken oil field in that state.

A spokesman for the U.S. transportation department said inspectors have found "inconsistencies with crude oil classification" in oil being shipped from North Dakota.

The train that derailed and exploded in Lac-Mégantic on July 6 is reported to have been carrying crude oil from that region.

Bakken oil more volatile

Scott Smith, who runs an oil spill clean-up company, travelled to North Dakota after testing water in the Chaudière River near the Lac-Mégantic spill.

He said some people may believe all crude oil is the same, but that’s simply not the case.

Smith said each type of oil has its own unique chemical composition, making some more volatile than others.

"Bakken oil has about 30 to 40 per cent of explosive, volatile chemicals referred to as PAHs… going into rail cars," Smith said.

He said oil transported by pipeline contains a lower percentage of those chemicals.

Smith spoke of his experience in North Dakota, saying that drilling companies are going deeper and deeper into the ground to draw out oil.

"Being on the ground in North Dakota, there is just massive drilling. The objective is to pump it and load it. No one is stopping to transparently, scientifically fingerprint, like a human being’s fingerprint, to understand what is in that oil before they transport it," Smith continued.

The U.S. Department of Transportation has launched a joint inspection operation to verify that crude oil, particularly Bakken oil, is properly classified.

"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," said spokesman Damon Hill of the department.

He said the operation’s planning began in March 2013 after audits and observations in the field found inconsistencies with crude oil classification and other federal safety regulations.