Chem Engineers’ review of TSB analysis of crude oil samples from Lac-Mégantic

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Oil in deadly train blast explosive as fuel

Canadian authorities test Lac Megantic oil

Richard Jansen  07/03/2014

Explosion

The oil was found to have a flash point similar to unleaded gasoline

THE oil shipment involved in last year’s deadly Lac Megantic disaster has characteristics closer to gasoline than normal crude, according to a report by Canadian authorities.

Almost 50 people were killed when a train carrying crude produced from the US’ Bakken shale play exploded into a fireball after derailing in the Canadian town of Lac Megantic. In the aftermath of the disaster questions were raised over how the oil reacted so violently, as the properties of regular crude should make it very unlikely to explode.

In its engineering report, the Transportation Safety Board (TSB) says that the level of hazard posed by the oil “was not accurately documented” when it had been shipped. Using samples taken from the handful of tankers that didn’t derail, the regulator found that the oil at Lac Megantic had an extremely low flash point – the temperature at which it will form a flammable mixture with air – “similar to that of unleaded gasoline.”

“The large quantities of spilled crude oil, the rapid rate of release, and the oil’s high volatility and low viscosity were likely the major contributors to the large post-derailment fireball and pool fire,” it concludes.

In the wake of Lac Megantic there have been several accidents involving oil being transported from North American shale plays. Late last year a 106-car train came off the rails near the town of Casselton in North Dakota, US, and exploded. Though none of the incidents since Lac Megantic have caused a fatality, transport regulators across the region have looked to improve their safety regulations, with the US Pipeline and Hazardous Materials Safety Administration announcing plans to reinforce its testing standards for crude.

The accidents have brought fresh attention to the increasing amount of oil transported across North America by rail. As production from shale oil and oil sands continues to grow faster than the pipeline network, rail has become an increasingly important method of transportation.

According to a report by the Association of American Railroads (AAR) released last year, in 2008 just 9,500 carloads of crude oil travelled by rail. By 2012 this had grown to nearly 234,000 carloads, with “another big jump” expected for 2013.

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