What was the Halifax Explosion of 1917?

The Halifax Explosion happened on the morning of 6 December 1917, when the French cargo ship Mont-Blanc, loaded with high explosives, collided with the Norwegian ship Imo in Halifax Harbour, Nova Scotia. Mont-Blanc caught fire and detonated, devastating the city's north end. It was the largest human-made explosion up to that time, before the atomic bombs of 1945. [1] [2]

Halifax was a busy wartime port and a gathering point for convoys crossing the Atlantic. Mont-Blanc carried benzol, picric acid, TNT and gun cotton. Before the war, civilian authorities kept such ships out of the inner harbour, but the British Admiralty had taken command of the port, and munitions ships were allowed into Bedford Basin. There was no special protocol for their passage. [2]

Imo, chartered to carry relief supplies for Belgium, was leaving the harbour. In the Narrows it was travelling on the eastern, Dartmouth side, which was not the usual lane for outbound ships, after earlier encounters with two inbound vessels. Mont-Blanc was inbound on that same side. After a series of whistle signals and failed manoeuvres, Imo struck Mont-Blanc's starboard bow. Sparks ignited picric acid and benzol, and the ship burned. [2] [3]

Mont-Blanc's pilot later maintained that Imo was going too fast and that incoming ships had right-of-way. The Canadian Encyclopedia notes that, whatever the merit of those claims, Imo was certainly too far east, in what should have been Mont-Blanc's path. [2]

The fire lasted about 20 minutes. Mont-Blanc's crew abandoned ship, and the vessel drifted to Pier 6 while crowds gathered to watch. At 9:04:35 a.m. it exploded, sending a shock wave in all directions and then a tsunami over the Halifax and Dartmouth shores. The energy released is estimated at about 2.9 kilotons of TNT. More than 2.5 square kilometres of the Richmond district were levelled by the blast, the wave or fires. Citadel Hill shielded the south and west ends of the city, where damage was mostly broken windows and displaced doors. [3] [2] [1]

Sources give different death tolls. Morgue records from 1918 showed 1,631 known dead or missing, and the Canadian Encyclopedia says the figure was revised to 1,946 by 2004. The Canadian War Museum gives an official toll of 1,963, while Wikipedia says at least 1,782. Parks Canada and others say roughly 2,000. All agree on about 9,000 injured, including hundreds blinded by flying glass. The Canadian Encyclopedia reports more than 1,500 buildings destroyed, 12,000 damaged, and 25,000 people without adequate shelter, a problem worsened by a blizzard the next day. The War Museum gives 6,000 homeless, so housing figures also vary. [2] [4] [1] [5]

The disaster prompted a large local, national and international outpouring of aid. Parks Canada says the many serious injuries led to advances in medical treatment, notably in pediatric surgery, and contributed to the creation of the Canadian National Institute for the Blind. Destroyed neighbourhoods were rebuilt to safer standards with innovative urban designs. [5] [3]