On a cold December 6, in 1917, it seemed as though the doors of hell had burst asunder in Halifax, Nova Scotia. French munitions ship the SS Mont-Blanc collided with Norwegian supply ship the Imo at 8:40 in the morning. Twenty-five minutes later, the biggest single man-made explosion prior to the atomic bomb tests of 1945 laid waste to the harbor and everything around it.
The force of the blast was so great that all the buildings within a 16-mile radius were all but obliterated and iron railings were bent like soda straws. A tsunami was created after water filled the space where the harbor bottom was briefly exposed due to the amount of water that had been vaporized. In total, 2,000 people were killed, with a further 9,000 injured. The city was devastated, and parts of it were turned into a wasteland as a built-up area of 500 acres on the nearby shore was wiped off the map.
Due to traffic congestion in the Narrows, a section where ships passed between the basin and outer harbor, the Norwegian ship Imo was not in the lane it should have been. The Mont-Blanc was moving in the other direction and blew its whistle in warning, but the Imo signaled it would not or could not change course. Hearing the signals, sailors on other boats gathered to watch the impending collision. Last-minute evasive action by both ships – the Imo reversing its engines and the Mont-Blanc turning hard to the left – actually contributed to their colliding.
When the two ships struck each other, the world changed forever in Halifax.
The Imo’s effort to disengage caused sparks to fly in the Mont-Blanc’s hull, and the benzol drums that had been crushed on the deck of the fully-loaded munitions ship were ignited by highly unstable picric acid. Very soon, the fire that started was out of control and the explosion became inevitable.