Mont Blanc 
- Name
- Mont Blanc
- Accident date
- 06/11/1917
- Location
- Canada
- Accident area
- port of Halifax (Canada)
- Spill area
- Port/harbour
- Cause of spill
- Collision
- Product transported
- explosives (TNT, guncotton, picric acid)
- Quantity transported
- 2,300 t. picric acid, 200 t. TNT, 35 t. benzole, 10 t. guncotton
- Nature of pollutant
- explosives
- Ship / structure type
- Cargo vessel
- Length
- 98 m
- Width
- 13.7 m
- Draught
- 4.7 m
- Flag
- French
- Owner
- Compagnie Générale Transatlantique
The incident
On 6 December 1917, in the port of Halifax (Nova Scotia – Canada), the French cargo vessel Mont Blanc collided with the Norwegian vessel Imo. The Mont Blanc went on fire and exploded, killing 2,000 people and injuring thousands of others within several kilometres around the ship. The French ship’s crew had been able to abandon ship in time and all but one survived; however 6 of the crew of the Imo were killed. The explosion caused a 2-metre high tsunami and a very powerful shockwave, destroying trees and buildings and projecting fragments of boat within a radius of several kilometres.
The Mont Blanc had been transporting large quantities of munitions to Europe where the First World War was raging: around 2,500 tonnes of explosives, including TNT, guncotton and picric acid.
Pollution
A little under a century after the disaster, cordite (a very soluble explosive) and unexploded munitions can still be found on the floor of the port of Halifax, where they are polluting the marine environment due to the presence of copper oxides used to dye cartridge cases blue. The munitions also contain mercury in the form of mercury fulminate and lead, representing a real water pollution risk.
Consequences of the accident
In May 1919, the Supreme Court of Canada found both the French and Norwegian vessels to be equally guilty. This judgment was confirmed by the Privy Council in London. The Canadian Government created a Relief Commission on 22 January 1918 in charge of allowances allocated to victims and compensation for material damages. This commission was not abolished until June 1976.
This was the largest explosion caused by human activity until the first atomic bomb test in 1945 and still figures among the largest artificial non-nuclear explosions.