In the Globe and Mail, Jacquie McNish and Grant Robertson report on the ongoing investigations into the causes of the fatal explosion:
Federal officials probing the Lac-Mégantic disaster are testing the chemical composition of crude oil carried by the runaway train as they seek to answer the crucial question of what triggered the unusual and devastating explosion after the derailment.
[…]
Edward Burkhardt, chairman of Montreal, Maine & Atlantic Railway Inc., which operated the derailed train, said Canadian authorities have impounded the rail cars to take “a huge number of samples of oil.” He said the investigators and officials in the rail and oil industries “are asking how come there were explosions here. Crude does not blow up.”
People familiar with the investigation said the TSB is examining the composition of the oil that fuelled the explosion.
Industry sources said there are several possibilities. One is whether the crude, which came from the Bakken oil region of North Dakota, contained volatile chemicals. A possible scenario is that additives were intentionally combined with the crude oil to speed up the transfer of the syrupy oil, common for pipelines but rare in the rail industry. Another possibility is that the tanker cars had chemical contaminants from a previous shipment. Another question is whether the oil contained high levels of flammable hydrogen sulphide gas, which is sometimes present in Bakken oil.
[…]
Regulators in the United States say rail carriers are responsible for knowing what they are carrying, and that the shipper and the railway company are required to work out such details when the train is being loaded.
“The carriers have to know exactly what it is that they’re hauling at all times,” said Warren Flateau, a spokesman for the Federal Railway Association in Washington.
Mr. Burkhardt said MM&A received a detailed bill of lading from the U.S. oil services company, which he declined to identify, and no chemicals were identified as being present in the crude. The intermediary oil services company leased the rail cars, loaded them with oil and then contracted three separate railway companies to transport them.
The first carrier was Canadian Pacific Railway, which handed over the train to MM&A in Montreal. From there, MM&A was to deliver the oil cars to a small rail company in New Brunswick owned by the Irving family.
But ah, I thought there was an existing locomotive fire that firefighters were called to, before the thing rolled downhill and derailed? And as a result of that initial fire, the system providing power/pressure to the locomotive brakes were disengaged by the firefighters? Resulting in the giant kablooie.
So doesn’t residual heat from pre-existing fire + lack of adequate braking power + friction on those brakes that were still applied pretty well account for ignition?
Comment by Chris Taylor — July 20, 2013 @ 22:29
Ignition, certainly, but not explosion. Crude oil is flammable, but under normal circumstances not at all explosive. This is one of the reasons that terrorism hadn’t been ruled out during the initial investigations.
Comment by Nicholas — July 21, 2013 @ 08:57
I’m no molecular chemist, but wouldn’t a whole lot of crude oil sitting around under intense heat be off-gassing fumes of some kind? And might they be explosive? There are explosions at oil refineries every couple of years. It can’t be that big of a mystery.
Comment by Chris Taylor — July 21, 2013 @ 19:46
The explosions at refineries, however, tend to be in the areas where the crude isn’t. Once you start refining the crude, you’re separating the more volatile components of the mixture … those components are much more likely to have energetic responses to certain kinds of stimuli (open flame, f’r instance). If there was a reasonable chance that crude oil in a metal tank would start to somehow produce more energetic gases, there are a dozen multi-national energy companies that would pay serious money to get the secret.
Comment by Nicholas — July 21, 2013 @ 20:07
It all boils down to the type of crude oil and at what stage of refining it was transported. Some varieties of crude oil can have very high natural gas content, and that would be no-brainer for big kabooms. There’s no monolithic standard for crude oil, as you know, it’s a catch-all term for “hasn’t yet been turned into the thing we want to sell”.
Comment by Chris Taylor — July 23, 2013 @ 10:07