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Dublin: 20°C Monday 15 August 2022

Halifax Explosion: The accidental blast that killed 2,000 people a century ago

In December 1917 a ship detonated in Nova Scotia, unleashing a blast equivalent to about 3,000 tonnes of TNT.

THE US MILITARY dropped the most powerful non-nuclear bomb in its arsenal on an Islamic State stronghold in Afghanistan yesterday .

Nicknamed the ‘Mother of All Bombs‘ (but officially called the GBU-43/B Massive Ordnance Air Blast Bomb), the 30-foot-long munition reportedly killed 36 ISIS fighters and crushed a network of caves, tunnels and bunkers dug into a remote mountainside.

The strike was akin to setting off about 11 tonnes of TNT — a school bus’ weight worth of explosives.

However, the attack pales in comparison to an accidental explosion that rocked a coastal town nearly three decades before the first atomic bomb.

On the morning of 6 December 1917, a ship detonated in the harbour of Halifax, Nova Scotia, unleashing a blast equivalent to about 3,000 tonnes of TNT.

The resulting shockwave instantly killed more than 1,000 people, threw a cargo ship like a bath toy and created a 50-foot-tall tidal wave.

This is the incredible and horrifying story of the Halifax Explosion: the largest human-made, non-nuclear blast in history.

By December 1917, World War I had been raging for three years. Halifax, located on Canada’s east coast, served as an important port for shipping troops and supplies to Europe.

by-december-1917-world-war-i-had-been-raging-for-three-years-halifax-located-on-canadas-east-coast-served-as-an-important-port-for-shipping-troops-and-supplies-to-europe Source: Nova Scotia Archives & Records Management/Wikimedia

On 6 December, a Norwegian cargo ship, the SS Imo, was departing Halifax on its way to New York. The ship was en route from the Netherlands to ferry supplies back to a war-ravaged Belgium.

on-december-6-a-norwegian-cargo-ship-the-ss-imo-was-departing-halifax-on-its-way-to-new-york-the-ship-was-en-route-from-the-netherlands-to-ferry-supplies-back-to-a-war-ravaged-belgium Source: Lectures pour tous/Wikimedia

Source: NASA

At the same time, the SS Mont Blanc was bound to return to France carrying a host of highly explosive materials: 2,367 tonnes of picric acid, 62 tonnes of guncotton, 250 tonnes of TNT and 246 tonnes of benzol in barrels below decks.

at-the-same-time-the-ss-mont-blanc-was-bound-to-return-to-france-carrying-a-host-of-highly-explosive-materials-2367-tons-of-picric-acid-62-tons-of-guncotton-250-tons-of-tnt-and-246-tons-of-benzol-in-barrels-below-decks Source: Public domain

Source: NASA

To exit the Bedford Basin, where the ships were docked, they had to pass through a slim channel. The Imo — behind schedule and on the wrong side of the channel — refused to give way and crashed into the Mont Blanc.

to-exit-the-bedford-basin-where-the-ships-were-docked-they-had-to-pass-through-a-slim-channel-the-imo--behind-schedule-and-on-the-wrong-side-of-the-channel--refused-to-give-way-and-crashed-into-the-mont-blanc Source: Google Maps/Tech Insider

Although the collision occurred at low speed, the benzol spilled and sparks ignited the entire stockpile of fuel. The Mont Blanc exploded with the force of 2,989 tonnes of TNT — about 270 times more powerful than a ‘Mother of All Bombs’ blast.

although-the-collision-occurred-at-low-speed-the-benzol-spilled-and-sparks-ignited-the-entire-stockpile-of-fuel-the-mont-blanc-exploded-with-the-force-of-2989-tons-of-tnt--about-270-times-more-powerful-than-a-mother-of-a Source: Library and Archives Canada/Wikimedia

Source: NASA 

The shock wave from the blast covered 325 acres of ground and levelled the neighborhood of Richmond.

The temperature of the explosion exceeded 9,000 degrees Fahrenheit (about 5,000 degrees Celsius), vapourising water around the Mont Blanc — and pushing a 52-foot-tall tidal wave three blocks into town.

the-shockwave-from-the-blast-covered-325-acres-of-ground-and-leveled-the-neighborhood-of-richmond-the-temperature-of-the-explosion-exceeded-9000-degrees-fahrenheit-vaporizing-water-around-the-mont-blanc--and-pushing-a-52 Source: W. G. McLaughlan/Flickr (CC BY 2.0)

Source: NASA

The force of the explosion lifted the Imo out of the water and threw it onto the shore. The Mont Blanc was ripped apart and completely destroyed. Almost no part of the ship survived the explosion.

the-force-of-the-explosion-lifted-the-imo-out-of-the-water-and-threw-it-onto-the-shore-the-mont-blanc-was-ripped-apart-and-completely-destroyed-almost-no-part-of-the-ship-survived-the-explosion Source: Nova Scotia Archives and Records Management/Wikimedia

Only two parts of the Mont Blanc have ever been located: a 1,140-lb piece of its anchor, found buried more than two miles away, and a barrel from one of the ship’s guns, which flew 2.35 miles from the blast site.

only-two-parts-of-the-mont-blanc-have-ever-been-located-a-1140-lb-piece-of-its-anchor-found-buried-more-than-2-miles-away-and-a-barrel-from-one-of-the-ships-guns-which-flew-235-miles-from-the-blast-site (1) Source: Vonkiegr8/Wikimedia

Source: NASA

Much of Halifax was levelled, with 12,000 buildings destroyed or made uninhabitable, leaving a huge portion of the city’s population without shelter from the frigid December weather.

much-of-halifax-was-leveled-with-12000-buildings-destroyed-or-made-uninhabitable-leaving-a-huge-portion-of-the-citys-population-without-shelter-from-the-frigid-december-weather (1) Source: George Grantham Bain collection/U.S. Library of Congress/Wikimedia

Source: NASA

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Almost every window in the city shattered — some reportedly 50 miles away. Even the buildings left standing were severely damaged.

almost-every-window-in-the-city-shattered--some-reportedly-50-miles-away-even-the-buildings-left-standing-were-severely-damaged Source: Library of Congress

Source: NASA

About 1,600 people died instantly in the blast, and 350 later succumbed to injuries. An estimated 9,000 people were injured in the accident, making 22% of the city’s population a casualty.

about-1600-people-died-instantly-in-the-blast-and-350-later-succumbed-to-injuries-an-estimated-9000-people-were-injured-in-the-accident-making-22-of-the-citys-population-a-casualty Source: Nova Scotia Archives and Records Management/Wikimedia

Source: NASA

Losses would have been even worse had a railway dispatcher, Vincent Coleman, not halted a train carrying 300 people towards the train station directly in front of the burning ship.

losses-would-have-been-even-worse-had-a-railway-dispatcher-vincent-coleman-not-halted-a-train-carrying-300-people-towards-the-train-station-directly-in-front-of-the-burning-ship Source: L'Illustration/Wikimedia

Source: Maritime Museum of the Atlantic

Coleman’s final action was sending a telegraph warning up the tracks: “Hold up the train. Ammunition ship afire in harbor making for Pier 6 and will explode. Guess this will be my last message. Good-bye boys.”

colemans-final-action-was-sending-a-telegraph-warning-up-the-tracks-hold-up-the-train-ammunition-ship-afire-in-harbor-making-for-pier-6-and-will-explode-guess-this-will-be-my-last-message-good-bye-boys Source: The Nova Scotia Museum/Wikimedia

Source: Maritime Museum of the Atlantic

The force of the Halifax explosion was so large that it remained the largest human-made explosion ever until the United States developed atomic weaponry in 1945.

the-force-of-the-halifax-explosion-was-so-large-that-it-remained-the-largest-human-made-explosion-ever-until-the-united-states-developed-atomic-weaponry-in-1945 The fireball of the Trinity nuclear bomb test of 16 July, 1945 Source: Wikimedia Commons

Dave Mosher, Business Insider (Sean Kane wrote a previous version of this post)

Read: What is the ‘Mother of All Bombs’?

Read: Massive US bomb ‘killed 36 ISIS fighters and destroyed tunnel network’

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