Today in Explosives History

And it was on this day in 1917 that an accidental explosion destroyed a quarter of the city of Halifax, Nova Scotia. It was the height of World War I, and Halifax was serving as an important port city for many of the ships carrying supplies for the battlefront in Europe. One of the ships coming into the port that day was a French warship called the Mont Blanc, carrying 200 tons of TNT, 2,300 tons of other explosives, as well as 10 tons of cotton and 35 tons of highly flammable chemicals stored in vats on the ship's upper deck.

As the Mont Blanc sailed through the narrow channel into the Halifax Harbor, it collided with a Norwegian freighter. The collision started a fire on the Mont Blanc, and the captain gave the order to abandon ship. The crew piled into lifeboats and then paddled frantically away. Unfortunately, the fire drew a crowd of onlookers along the shore of the channel. The docks filled with spectators, trams slowed down, people stood at office windows and on factory roofs to see the blaze. Then, a few minutes after the fire had started, the Mont Blanc exploded.

It was the single most powerful man-made explosion at that point in human history, and there wouldn't be another more powerful explosion until the first atom bomb was dropped on Hiroshima.

The blast wave of water hit the shore, sweeping away buildings, bridges, roads, vehicles, and people. City streets split open into deep fissures. Houses, churches, schools, and factories collapsed. The entire city was showered with debris. Virtually every building in the city had its windows broken. About a quarter of the city, within a square mile of the blast, was completely destroyed.

Almost 2,000 people were killed in the blast and as many as 9,000 were seriously injured, many of them blinded by pieces of broken glass. Thousands of people were left homeless in the middle of a bitter winter. Volunteers poured in from the United States and Great Britain to help in the recovery efforts, and children who survived the blast were photographed for postcards to be sold to help rebuild the city.

Even though World War I was being fought across the Atlantic, Halifax was damaged far greater than any European city. It is the worst disaster of any kind in Canadian history.