The Halifax Explosion was the largest human-made explosion prior to nuclear weapons, killing at least 1,782 people and devastating the city of Halifax.
Key Facts
- Date
- 6 December 1917
- Death toll
- At least 1,782 people
- Injured
- Approximately 9,000 people
- Blast yield
- ~2.9 kilotons of TNT kt TNT
- Destruction radius
- 800 metres (half-mile)
- Collision speed
- Approximately 1 knot knots
By the Numbers
Location
Cause → Event → Consequence
The French cargo ship SS Mont-Blanc, carrying high explosives from New York City bound for Bordeaux, entered Halifax Harbour on the morning of 6 December 1917. The unladen Norwegian vessel SS Imo, chartered to collect relief supplies, collided with her at low speed. The impact ruptured benzol barrels on deck, releasing vapours ignited by collision sparks, starting an uncontrollable fire aboard the explosives-laden vessel.
Approximately 20 minutes after the collision, at 9:04:35 am, SS Mont-Blanc detonated in Halifax Harbour, releasing energy equivalent to roughly 2.9 kilotons of TNT. The blast obliterated nearly all structures within an 800-metre radius, including the Richmond district, snapped trees, demolished buildings, and generated a tsunami that struck both Halifax and Dartmouth shores, wiping out a Mi'kmaq community at Tufts Cove.
At least 1,782 people were killed and an estimated 9,000 injured, with widespread homelessness resulting from the destruction. Relief trains arrived from across Nova Scotia, New Brunswick, and central Canada, though blizzards delayed some aid. Temporary shelters were erected and hospitals overwhelmed. A judicial inquiry initially blamed Mont-Blanc, though an appeal found both vessels at fault. Several memorials now stand in Halifax's North End to commemorate the victims.
Human Cost
Each dot represents approximately 10,000 deaths. Total estimated: 1,782 (other)