
At 9:05 am on December 6th, 1917, the most devastating man-made explosion, short of the Hiroshima Atomic Bomb, occurred in the port of Halifax, Nova Scotia in Canada. A French ship, the Mont Blanc, its hold packed with tons of war-bound munitions, explodes after colliding with another vessel, the Imo.
Why Halifax? In 1917, World War I still raged on in Europe. The port of Halifax was the departure port for Canadian transatlantic convoys leaving to supply the troops overseas. It was packed with ships carrying soldiers, supplies, and munitions across the Atlantic. In a matter of 3 short years, the small harbor town had grown into a world class port and major Canadian naval base.
World War I had brought prosperity, and Halifax became a boom town.
That frigid December morning, the port city was swollen with people and a bee hive of activity. Canadian troops bound for battle in the trenches of France flooded the streets, hundreds of laborers trudged to work, and children of all ages wandered off to their schools.
At 7:30 am on the morning of December 6th, the Mont Blanc left it anchorage and began cruising through the Halifax narrows. Its orders to join a military convoy that would escort it across the Atlantic Ocean. Unbeknownst to the average citizen, its cargo hold was packed with 2,300 tons of explosive picric acid, 200 tons of TNT, 35 tons of gasoline, and 10 tons of flammable gun cotton! At the exact same time, the Norwegian ship Imo left its Halifax pier bound for New York City to pick up its own load of relief supplies.
At 8:45 am, at the entrance to the Narrows, confusion ensued between the two closing ships with a series of misjudged maneuvers and whistle blasts. There was inter-ship radio back then. The Imo struck the Mont Blanc near the bow. Although the collision was hardly severe, the shock waves set the picric acid drums in the hold ablaze and the fire quickly spread onboard the Mont Blanc. The captain and harbor pilot, aware of exactly what their cargo was, knew they now stood on a massive ticking time bomb! They attempted to alert the harbor of the peril of their burning ship, but were unsuccessful.
Expecting an explosion any second, the captain quickly order his crew to abandon ship.
They launched their lifeboats and took refuge on the nearby shore of the narrows. The Mont Blanc was knocked off course by the collision and slowly coasted back towards Halifax. The ship burned for twenty minutes, sending pillars of black smoke pluming into the grey winter sky. It drifted back into the harbor until it bounced against Pier 6, at the busy, industrial end of Halifax. Burning pieces fell off, setting the pier ablaze as well.
The spectacle was thrilling and drew crowds of innocent spectators, unaware of the immense danger simmering before their eyes. Only a handful of naval officers even knew of the Mont-Blanc’s explosive cargo, but there would be no time for any city-wide warning. A tugboat and the Halifax Fire Department quickly responded, positioning themselves near Pier 6.
That’s when the Mont Blanc and its tons of munitions exploded in a flash of blinding white light.
Factories, warehouses, schools, homes and nearby ships were completely destroyed in the pressure wave of the blast. White-hot fragments of the Mont Blanc rained down on the city, crashing through buildings with enough force to embed themselves in cellars. Children who had stopped on their way to school, workmen lining factory windows, sailors in their ships, all died instantly.
The resulting shock wave shattered windows 50 miles away, and the explosion could be heard as far as Portland, Maine. Hardly a pane of glass in Halifax survived. In seconds, the majority of the city was reduced to ruins and rubble. Many who survived thought the Germans must have bombed them.

Survivors’ injuries were frightful, including third degree burns and blindness from the flash, or embedded splintering glass. Rescue efforts began quickly, but hospitals and shelters were soon overwhelmed. All surviving buildings, including ships in the harbor, were commandeered as hospitals.
The colossal explosion destroyed the entire north end of Halifax, including more than 1,630 homes, many by the hundreds of fires that quickly spread. The blast killed more than 2,000 people, injuring another 9,000. The flash of the explosion blinded 200 alone. 6,000 survivors were left without shelter. The captain, pilot and crew of the Imo were all killed. All the crew from the Mont Blanc survived.
Not one piece of the Mont Blanc remained after the blast.
In the months that followed, both ships’ crews were judged equally at fault. Captain Aime Le Medec and pilot Francis Mackey of the Mont Blanc were charged with manslaughter. Later, the charges were dropped, because gross negligence causing death could not be proven in court. About 250 bodies were too disfigured to be identified; many of the victims were simply never found.
In 1920, a Memorial Tower containing a carillon of bells, was erected at Fort Needham, overlooking the Halifax explosion site. The dedication was made by a young girl who had lost her entire family in the terrible blast. Every year since, at exactly 9:00 am on December 6th, the sweet sound of the carillon’s bells ring out over Halifax in memory of the victims of the terrible Mont Blanc explosion.