Edward Burkhardt, the president and CEO of the railway's parent company Rail World, Inc., suggested that the decision to shut off the locomotive to put out the fire might have disabled the brakes. "An hour or so after the locomotive was shut down, the train rolled away," Burkhardt told the Canadian Broadcast Corp.
Meanwhile, crews were working to contain 100,000 liters (27,000 gallons) of light crude that spilled from the tankers and made its way into nearby waterways. There were fears it could flow into the St. Lawrence River all the way to Quebec City.
Quebec's Environment Ministry Spokesman Eric Cardinal said officials remained hopeful they could contain more than 85 per cent of the spill.
The growing number of trains transporting crude oil in Canada and the United States had raised concerns of a major disaster. Canadian Prime Minister Stephen Harper, who has been pushing the Obama administration to approve the controversial Keystone XL oil pipeline from Canada to the U.S. Gulf Coast, has said railroad transit is more "environmentally challenging" than pipelines.
The train's oil was being transported from North Dakota's Bakken oil region to a refinery in New Brunswick on Canada's East Coast. Because of limited pipeline capacity in the Bakken region and in Canada, oil producers are increasingly using railroads to transport oil to refineries.
The Canadian Railway Association recently estimated that as many as 140,000 carloads of crude oil will be shipped on Canada's tracks this year — up from 500 carloads in 2009. The Quebec disaster is the fourth freight train accident in Canada under investigation involving crude oil shipments since the beginning of the year.