The deadly secret behind the Lac-Mégantic inferno

Emergency crews ran for cover when they heard the noise, as they fought blasts of burning oil during the Lac-Mégantic rail disaster. The kettle-boil scream meant one thing: Oil vapours were shooting out of a derailed tank car and another fireball was about to rip from the broken train. It wasn’t until four days after the July 6 derailment that the fires finally subsided. But even before the inferno was extinguished and the burned-out town counted its 47 dead, rescue workers and rail, petroleum and government officials were asking the same troubling question: Why was the oil so explosive?