OTTAWA -- The crude oil that exploded into flames in the deadly Lac-Mégantic train derailment in July was as volatile as gasoline, but was documented as a less-dangerous product akin to diesel or bunker crude, the Transportation Safety Board says.
Lead investigator Don Ross said tests showed the oil was initially graded properly for road transport but was inexplicably downgraded when it came time to move it by rail.
"When we analyzed the product samples from the nine intact tank cars from the Lac-Mégantic accident, we identified the product as having the characteristics of a packing group 2 flammable liquid," he told a news conference Wednesday.
"Packing group 2 is the packing group that gasoline is in."
The Lac-Mégantic oil was improperly identified as a less-hazardous packing group 3 product, and investigators want to know why.
"We're asking those questions," Ross said.
"Is there any motivation? Why would that be shown the way it was, whether there was any commercial interest, any operating reason? We're asking all those questions."
The July 6 crash killed 47 people and destroyed much of the centre of the picturesque Quebec town after an unmanned, runaway train derailed and exploded in a fireball.
Almost immediately, there were questions about why a rupture of crude-oil tank cars proved so explosive.
The TSB analyzed the Lac-Mégantic oil, as well as from another train farther down the tracks carrying crude from the same supplier. Both were more volatile than their placards indicated.
"The lower flash point of the crude oil explains in part why the crude oil ignited so quickly once the Class 111 tank cars were breached," Ross said.
The board's report says the oil in the train came from 11 different wells in the Bakken Shale formation of North Dakota. The various shipments had initially been classified differently, with some rated in the most volatile packing group 1.
When trucked to the rail terminal by several different firms, the oil was all labelled group 2.
But for purposes of the rail shipment to Saint John, N.B., the entire load was graded as the least volatile packing group 3.
-- The Canadian Press