The Halifax Explosion


On the morning of December 6, 1917 in Halifax’s harbour, a collision between the Norwegian vessel SS Imo and the French munitions carrier SS Mont Blanc caused the largest man-made explosion prior to the atomic bomb. With a force equivalent to 2.9 kilotons of TNT, it killed nearly 2,000 people, injured another 9,000, destroyed 1,630 homes and damaged thousands more. It left 6,000 people homeless. The unprecedented scale of the devastation caused a tremendous national and international outpouring of aid and support, most notably from the City of Boston and the Commonwealth of Massachusetts. Locally and nationally, the explosion had profound and long-lasting consequences in the areas of medicine, public health and social welfare, and resulted in the rebuilding of devastated areas to safer standards.

In 1917, Halifax was fully embroiled in the First World War. Its harbour served as an assembly and departure point for transatlantic convoys carrying troops and supplies overseas. SS Imo, under charter to the Belgian Relief Commission, was bound for New York to pick up relief supplies. SS Mont Blanc, heavily laden with explosives, was heading into the basin to join a convoy. Upon collision, a fire broke out on Mont Blanc and the crew – fearing an immediate explosion – abandoned ship. The fire continued for approximately 20 minutes, while the ship drifted, eventually coming to rest against Pier 6. The collision and fire attracted a large crowd of spectators. Only a handful of naval officers were aware of the looming danger. Shortly after 9:04 a.m., the volatile cargo of Mont Blanc exploded. Flying debris, fires and collapsing buildings killed or injured thousands of people. The blast created a massive tsunami that crashed against the shores of the North End of Halifax and Dartmouth.

The scale of the devastation was akin only to the waste of war. Few structures within 500 metres of the blast site were left standing and most of those that remained were beyond repair. The community of Richmond lay in ruins and other parts of the North End of Halifax and Dartmouth suffered extensive damage. Most of the deaths occurred within two kilometres of the epicentre but in other parts of the city, people suffered terrible wounds, particularly from flying glass. Rescue efforts got immediately underway and relief committees were formed within hours. Nearby communities offered to take the wounded and homeless, as hospitals and shelters were quickly overrun. Trains carried supplies and medical personnel from other parts of Canada and from the United States. The city of Boston had a train loaded and heading to Halifax within hours of the explosion.  

In its aftermath, rebuilding the destroyed working-class neighbourhood of Richmond encouraged the rapid implementation of innovative civic and social projects, including a 1921 master town plan for Halifax’s North End that led to Canada’s first public-housing project. At the same time, medical treatment, social welfare and public health saw advances and improvements in the explosion’s wake. The large number of serious eye injuries caused by the blast provided a major impetus for the formation of the Canadian National Institute for the Blind. The treatment of burn victims, many of whom were children, allowed for advances in pediatric surgery related to fluid and electrolyte imbalances. The Halifax Explosion is considered by many historians to be a defining moment in Canadian history that, for many Canadians, “brought the war home.”

General View of Halifax, N.S after Explosion (Dec 6, 1917) from waterfront (Library and Archives Canada).

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