A Montreal, Maine & Atlantic train carrying 72 tank cars filled with oil exploded after it unexpectedly began rolling and went off the tracks in the small Quebec town on July 6, taking an estimated 47 lives.
The disaster — one of the worst rail accidents in Canadian history — has prompted as many as nine investigations and extensive discussion about how best to prevent a similar tragedy. Many seek urgent solutions given projections of steadily rising petroleum shipments by train.
The Canadian rail industry points to an improving safety record, noting the number of derailments — including those involving dangerous goods — is stable or decreasing.
There were six main-track derailments involving dangerous materials from January to May of this year, below the 2008-12 average of eight for the same time period. Derailments involving hazardous goods on secondary tracks stood at 34 for January to May this year, below the 2008-12 average of 37 for these months.
The Railway Association of Canada says 99.9977 per cent of all dangerous goods shipped by rail reach their destination without a release caused by a train accident. It adds that the oil spillage rate is lower for railways than for pipelines.
Those who study catastrophes say the numbers don't tell the whole story.
A major derailment of a train carrying large quantities of oil is what disaster experts call a low-probability, high-consequence event. In other words, it's not likely to happen, but if it does the fallout may well be devastating.
"These are totally different from other types of train crashes," said Ali Asgary, an associate professor of emergency management at York University in Toronto.
The rail industry has a very good safety record compared with other modes of transportation, said Manish Verma, an associate professor at McMaster University's DeGroote School of Business in Hamilton, Ont.
But that means only so much when dozens of tank cars filled with oil are passing through a community. "Even if something minor happens, the consequence could be very, very huge," he said.
Previously a train might have a handful of tank cars carrying chlorine or other such hazardous goods, notes Keith Stewart, climate and energy campaign co-ordinator with Greenpeace Canada. Now a train might have scores of cars transporting oil to a refinery.
"That's relatively new, and it's a lot more dangerous because the consequences when something goes wrong are much higher," Stewart said.
"I'd look at it as loading the dice in favour of disaster."
In 2009, major railways moved just 500 carloads of crude oil, but that has jumped to about 140,000 carloads a year, the railway association says.
While only about three per cent of Canadian crude moves by rail, one industry estimate has the figure rising to as high as 25 per cent by 2035.
Last week, in a preliminary response to the Lac-Megantic derailment, Transport Canada issued a series of emergency orders. From now on, at least two crew members must work trains that carry dangerous goods. In addition, no locomotive attached to a tank car filled with dangerous materials can be left unattended on a main track.
But those concerned about the hazards of transporting oil by train say much more must be done.
"You can never have absolute safety with moving fossil fuels, but it can be a lot safer than it is today," Stewart said. "We just think the federal government hasn't done its job, which is to set the rules in a way that protects community safety and the environment."
Among the suggested solutions: ensuring the tank cars used to move crude oil will not easily rupture, giving trains with large amounts of crude priority in order to avoid unnecessary stops and delays, diverting trains carrying oil away from towns and cities, and shielding populated areas by reclaiming land around tracks or building barriers to protect people.
Stewart would like to see broad public hearings on the movement of oil by all modes, including rail, truck, pipeline and ship.
The Railway Association of Canada refused to make anyone available for an interview. However, in a recent commentary posted on the association's website, president Michael Bourque says operators continue to improve safety when it comes to transporting crude oil and other dangerous goods.
A May 2012 Transport Canada memo, obtained by Greenpeace Canada, said the department had "identified no major safety concerns with the increased oil on rail capacity in Canada, nor with the safety of tank cars that are designed, maintained, qualified and used according to Canadian and U.S. standards and regulations.
"Indeed, Canada and the U.S. work collaboratively to ensure the harmonization of rail safety requirements."
The same wording appears in versions of the memo prepared as recently as January.
Asked during a conference call with reporters last week whether Transport Canada stands by that assessment, Gerard McDonald, the department's assistant deputy minister of safety and security, declined to discuss the internal memo.
Stewart points to a Transportation Safety Board recommendation that stricter safety provisions apply to all Class 111A tank cars that carry crude oil, not just a limited segment. A 2013 board assessment says the watchdog will continue to monitor the issue, concluding that "a large number of the existing tank cars carrying dangerous goods will be vulnerable to puncture, even during derailments at moderate operating speeds."
Verma acknowledges that altering routes to avoid populated areas would be expensive, but says it should be a collaborative effort between rail operators, governments and regulators.
Asgary fears the possibility of an oil-fuelled derailment fire in a large city.
"We should look at the worst-case scenarios when we are dealing with these type of activities and how we can handle them — or if we can handle them, really."
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