“We will find out how and why this happened so that it will hopefully never happen again,” Donald Ross, the lead TSB investigator, said at a news conference Thursday morning in the small town in the Eastern Townships.
The focus will now shift to the TSB’s laboratory in Ottawa, where tests are being conducted on samples of the oil taken from the scene, the train’s brakes, as well as other evidence gathered over the four weeks the agency was on the ground in the red zone of the disaster.
The TSB cautioned that process could take months, but insisted that any pertinent findings that could have an impact on safety would be communicated to Transport Canada, the industry and the public.
In total, 47 people were killed in the July 6 derailment and explosion that levelled much the town’s core.
Several other investigations, including a criminal investigation launched by Quebec provincial police, are also ongoing
'Crude oil acted in an abnormal manner'
The blast produced by the crude oil carried in the cars was shocking even to officials on the scene, the TSB investigators said.
“Certainly for crude oil, based on the experts’ views, it would seem that the crude oil reacted in an abnormal manner,” said Ed Belkaloul, the TSB's manager for Eastern Region Rail Operations.
"Analysis is being carried out to help us determine why the oil created such a fierce fire that night."
Samples collected are being tested to determine the exact composition of that oil, he said.
The tanker cars themselves and their viability in the crash, an issue that the TSB has already raised with Transport Canada earlier into their investigation in the disaster, will also be part of that investigation.
Several changes have already been instituted in the wake of the derailment in Lac-Mégantic.
Last week, Transport Canada issued an emergency directive requiring at least two crew members to work trains that transport dangerous goods.
It also says no locomotive attached to one or more loaded tank cars transporting dangerous goods can be left unattended on a main track.
Canadian Pacific Railway also updated its general operating instructions, which now require that any locomotive left unattended outside a station or yard be locked and prohibiting any tankers containing regulated commodities from being left unattended on main line tracks.
The TSB has already disclosed that its early findings showed the train was unmanned when it rolled down a 1.2 per cent incline from the nearby town of Nantes and derailed in Lac-Mégantic.
That train, when in operation, also had only one engineer on board, something only two rail carriers in Canada are permitted to do under federal regulations.