Halifax Explosion

The Halifax Explosion was a catastrophic explosion on 6 December 1917 in Halifax Harbour, Nova Scotia, caused by the collision and fire of the munitions ship SS Mont Blanc and the cargo ship SS Imo.

The Halifax Explosion was a catastrophic disaster on 6 December 1917 in Halifax Harbour, Nova Scotia, caused by the collision and fire of the munitions ship SS Mont Blanc and the cargo ship SS Imo.

What it is

The Halifax Explosion was the largest man-made explosion before the atomic bomb era. It occurred when SS Mont Blanc, carrying explosives bound for Europe during the First World War, collided with SS Imo in Halifax Harbour. The resulting blast killed about 2,000 people, injured about 9,000, and flattened more than a square mile of the city.

Key details

The explosion happened on the morning of 6 December 1917. It devastated large parts of Halifax and Dartmouth, destroying thousands of buildings and leaving many residents homeless. The blast also caused fires, collapsed structures, and a destructive wave. Exact casualty counts vary slightly by source, but the commonly cited figures are about 2,000 deaths and about 9,000 injuries.

Why it matters

The Halifax Explosion is a major event in Canadian history, especially for Nova Scotia and Atlantic Canada. It shaped Halifax’s urban development, disaster response practices, and collective memory. The disaster prompted extensive rescue, medical, and relief efforts, and remains one of the most studied disasters in Canadian history.