“The Halifax Explosion”


In Halifax harbor, a ship loaded with explosives is rammed by another vessel. The explosion and fire which follow cause terrible damage to the city and its population -- 1200 killed and 2000 wounded


The Halifax explosion has been called "the second most devastating blast in history" (behind Hiroshima; it actually did more damage than Nagasaki). As a survivor said, "Halifax was gone." Not surprisingly, it inspired several books. The most recent as of this writing is Laura M. MacDonald, _The Curse of the Narrows_, Walker, 2005, written by a resident of Halifax (or, rather, by a resident of Dartmouth, the city on the other side of Halifax Harbour; apparently Dartmouth residents don't like being treated as part of Halifax). I have also used Joyce Glasner, _The Halifax Explosion: Surviving the Blast that Shook a Nation_, Altitude, 2003.

Glasner is a short, undocumented, rather sensational book (the series title is "Amazing Stories"!), though I've cited it where is seems useful. MacDonald's long account is properly footnoted and agrees with the short accounts I've read in other sources (e.g. the story of the _Mont Blanc_ in Lincoln P. Paine's _Ships of the World_). What follows is mostly condensed from MacDonald, though I've tried to tell the story in more linear fashion (MacDonald spends much time talking about what people on shore were thinking; if I hadn't read the outline in Paine, I would have found her account very difficult to understand. As it is, reading MacDonald felt like I was watching a television drama where she took a commercial break every few pages).

To briefly sum up, the Halifax Explosion took place when the French munitions freighter _Mont Blanc_ and the Norwegian _Imo_ collided in Halifax harbor. The _Mont Blanc_ was scheduled to make a run to Britain with a large load of explosives when the _Imo_, also bound to sea and sloppily steered, collided with it. The impact was not particularly damaging in itself, but it struck sparks, starting a fire on the French ship. The captain, rather than fight the fires, ordered the crew to abandon ship. Twenty minutes later, burning and floating aimlessly, it ran up against a pier. The ship exploded, causing much damage and also starting a great wave which added to the damage.

If it weren't so tragic, the story of the _Mont Blanc_ would be almost comic. Why in the world was such a lousy ship used for such an important purpose? The cargo consisted mostly of explosives (though no one not on the ship knew this, because -- this being wartime -- the standard red explosives flag was not shown; Glasner, p. 35), along with a large amount of gasoline-related fuels (MacDonald, p. 16). Originally launched in 1899 (see Paine), she had been refitted to hold her cargo (e.g. the nails in her hold had been replaced by copper to avoid striking sparks; MacDonald, p. 17).

All this in a ship with an inexperienced crew and a captain who was new to his ship (he had only reached the rank of captain in 1916; Glasner, p. 15) and had little English (MacDonald, pp. 15-16). In a crisis, he would not know how to deal with his ship. It probably didn't help that he had never been to Halifax before, either (Glasner, p. 26).

The real problem was her speed. The best the _Mont Blanc_ could manage was about eight knots, and over a long stretch, she would probably not be able to exceed seven and a half. In fact, Glasner, p. 14, says that with her current loading she could barely make seven knots. By 1917, submarines were doing great damage, and the British were convoying their ships. The _Mont Blanc_ was too slow to sail direct from New York to Britain. She would have to go to Halifax to join one of the slow convoys there -- and even that might be pushing her abilities (MacDonald, p. 18). The later description "Large Slow Target" would have been a brilliant description of the _Mont Blanc_.

And Halifax was by this time the major shipment point from Canada to Britain. Fears of submarines had caused the harbor to be made more secure. There were anti-submarine nets at the entrance which were closed at sunset. When the _Mont Blanc_ arrived, the gates were shut for the day; she had to spend the night outside (Glasner, pp. 14, 16; MacDonald, p. 16), and then join what we might call the morning rush hour.

The other ship involved was also trapped by the submarine precautions. The _Imo_ had been launched as the White Star Lines ship _Runic_, but had been sold and was now a Norwegian tramp steamer used among other things to ferry food to civilians in Belgium. Her crew had recently spent a lot more time sitting around than sailing, and were probably very disappointed when they failed to make past the submarine barriers before they closed for the day (MacDonald, p. 20); they had had to wait for a shipment of coal (Glasner, p. 27).

The shape of the bay contributed to the problem. Halifax is an excellent port, with a large inner bay (the Bedford Basin) capable of holding many ships. But the basin is reached by "the Narrows" -- a long channel only about a third of a mile wide -- good for security, since it's easy to guard and control (Glasner, pp. 16-17) but a definite traffic bottleneck. Two ships can pass each other in the Narrows, but only if they stay on their proper courses. Ships going in and out have to be steered by pilots experienced in entering the channel. (Many harbors of course require such pilots, but few need them as much as Halifax).

The _Imo_, in its haste, broke the rules. As she left the Bedford Basin, she encountered the _Clara_. The standard for ships at Halifax was to pass "port to port" -- that is, as we might say it, to "keep on the right side of the road." But, because of where the ships were located, it was quicker to pass "starboard to starboard." The _Imo_ ended up on the wrong side of the channel (MacDonald, p. 30). And she then noticed another ship, the _Stella Maris_, pulling two scows near the south bank (MacDonald, p. 32-34). And there was some haze over the Narrows (MacDonald, p. 31). Despite this, the _Imo_ did not slow down; a witness reported, "She is going as fast as any ship I ever saw in the harbor" (MacDonald, p. 33). According to Glasner, p. 27, she was moving at seven knots, two knots faster than the harbor speed limit, though it's not clear how this was determined.

The pilot of the _Mont Blanc_, Francis Mackey, apparently spotted the _Imo_ first, though all he could see in the fog was her masts. He ordered the _Mont Blanc_ to edge toward the starboard (northeast) bank. He sent whistle signals to the _Imo_ (MacDonald, p. 38).

Unfortunately, there was a mixup in the whistle signals. Mackey gathered that the _Imo_, already far out of her lane, intended to stay there. He couldn't head closer to the shore on the starboard side; he was as close as he dared to take the heavily-laden ship. He steered her to port and let the ship stop (MacDonald, pp. 39-40).

The _Imo_ once again reacted improperly. Instead of steering around the _Mont Blanc_, she ordered her engines to reverse. Which, because she had no cargo, was a largely useless order; her screw was too high to have much power, and she was slow to answer the helm (MacDonald, p. 40). The captain and pilot on the _Mont Blanc_ tried to put their ship in reverse. It was too late. The _Imo_ crashed into her starboard side (MacDonald, p. 41).

Only then, far too late, did the _Imo_ manage to actually start moving backward. She backed out of the _Mont Blanc_, causing further damage. And, in the process, she did something which started a spark (Glasner, p. 29, thinks the grinding of metal on metal that did it). Whatever it was, it was the caused the petroleum on the _Mont Blanc's_ deck to catch fire. An oil fire, the kind that cannot be put out just with water -- even if the _Mont Blanc_ had had hoses able to reach the spot, which it didn't (MacDonald, p. 43). It appeared there was nothing the crew could do. The ship couldn't even be scuttled; the seacocks were rusted shut (Glasner, p. 30; MacDonald, p. 48). They abandoned ship -- and headed for the Dartmouth shore, so they didn't even give the city authorities a warning..

It's not quite certain what they did before abandoning. Did they change course? Start up the engines? The witnesses disagree. Whatever they did, the ship for some reason drifted across the Narrows to bump into a pier on the Halifax shore (MacDonald, p. 42).

Various ships came around to try to pull the ship back into mid-channel, or put out her fires (Glasner, pp. 32-39, lists some of the attempts). It was useless. She was too big to move and burning too hard to control the fire (MacDonald, pp. 50-51). Gradually the barrels of benzol and monochlorobenzol cooked off. Eventually, they set off the high explosive in the hold (at 9:04:35 a.m., according to later seismic measurements; MacDonald, p. 181, etc.).

It was quite a haul. 200 tons of TNT. Ten tons of guncotton (nitrocellulose: cotton fibers treated with nitric acid. Horribly touchy when dry. Safe enough when wet, but how could it stay wet when surrounded by benzol fires?) Worst of all, 2300 tons of picric acid, some wet, some dry.

Picric Acid -- (NO2)3C6H2OH -- is a "very poisonous, yellow, crystalline, intensely bitter acid used in explosive" (so the _American Heritage Dictionary of Science_). It was the primary component of lyddite ("picric acid... mixed with 10% nitrobenzene and 3% Vaseline," according to the _Penguin Dictionary of Science_). Lyddite was used by the British as a shell burster (i.e. it's what made shells blow up when they hit something), and picric acid was the active ingredient; when dry, it explodes upon being subjected to pressure (e.g. being hit by a hammer, or of course colliding with an enemy ship or trench). It would also burn explosively if heated.

Although less familiar than TNT, because it is so much touchier, picric acid actually releases more energy when it explodes.

Picric acid was dangerous on other grounds. According to Floyd L. Darrow, _The Story of Chemistry_, Chautauqua Press, 1928, p. 250, it also could be made into poison gas: "Chloropicrin, made from picric acid by the action of chlorine, was another [gas used in World War I]. It was mixed in a shell or bomb with tin chloride, which forms dense white clouds of vapor capable of penetrating the gas masks and carrying with it the volatile chloropicrin. Highly poisonous in itself, chloropicrin induces nausea and vomiting, thereby causing the victim to remove his mask and rendering him an easy prey to other lethal gases."

(If you're wondering why, given its dangers, picric acid was being made in Canada and shipped to Britain, rather than manufacturing in Britain, the basic answer is "nitrates." Picric acid, like every other major explosive used in the early twentieth century, required saltpeter or an equivalent nitrate source -- and the main source of nitrates was the west coast of Latin America. It was much easier to get them to Canada than to Britain in the days of submarine warfare. For more on this history of nitrates, see the notes to "Chamber Lye" and "Tommy's Gone to Hilo.")

MacDonald, p. 61, says that there were 2925 tons of explosives, total, on the _Mont Blanc_. The temperature of the explosion is thought to have been in the 5000C/9000F range (MacDonald, p. 62). In the era of conventional bombs, the largest ever used was about 10 tons. 2925 tons of mostly picric acid is in the nuclear weapons range -- at the very low end of the range (less than Hiroshima or Nagasaki by an order of about five), but unlike anything the world had ever seen in 1917, except for volcanic eruptions and meteor strikes.

The explosion was heard over 200 miles away, on Cape Breton and Prince Edward Island (Glasner, p. 81; MacDonald, p. 63). The _Mont Blanc's_ anchor was thrown more than two miles, and other parts of the ship went three miles (MacDonald, p. 67).

People died in many ways. Possibly as many as 150 were simply vaporized and never found. More were killed by the pressure wave -- pulverized to death. Others died by being thrown into walls or other objections. Flying glass killed and maimed many more. All buildings within half a mile of the blast were destroyed (MacDonald, p. 64). The blast was so strong that it spawned secondary tornadoes (MacDonald, p. 66). It also caused a 20-foot-high wave to scour the Halifax basin, at some places reaching six blocks inland (MacDonald, map in frontispiece).

There were secondary effects -- fires, even the collapse of a magazine at a military base. It didn't explode, but it did burn a bit, putting out enough smoke to cause a secondary panic (Glasner, pp. 61-65).

Relief efforts were at first quite disorganized. The mayor of Halifax was away, leaving the Deputy Mayor in charge (Glasner, p. 55; MacDonald, p. 93). The fire chief had been killed (MacDonald, p. 94), as had many of the firefighters, and the city's one fire engine ruined (Glasner, p. 120). Many doctors were killed or hurt and unable to treat patients (MacDonald, p. 112). The hospitals ranged from damaged to almost completely unusable (MacDonald, p. 113). Medical supplies soon ran low, and the only way to sterilize equipment was to put it in boiling water (MacDonald, p. 118). Doctors operated on patients without anesthesia, and sewed up their wounds with ordinary cotton thread (Glasner, p. 94).

It was hard to bring in help from outside. The railroads had been damaged, or were blocked by ruined trains, and many telegraph lines were down. Only one rail line, in fact, was fully serviceable, and it was a new line, not yet up and running (MacDonald, p. 111).

The temperature that night was well below freezing (MacDonald, p. 143), and there followed a fierce blizzard, causing additional deaths (MacDonald, p. 145) and adding to the strain on the survivors and making it that much harder to bring in help.

The casualties could never be perfectly counted. MacDonald's Appendix D, p. 291, lists 1611 official dead as of 1918; p. 293 lists 1201 bodies as buried, with 242 of them unidentified and 410 bodies missing -- but she reckons the known dead as of 2004 as 1952. She lists (p. 66) 6000 people as injured and 9000 as homeless. Others reverse those figures. Glasner, p. 41, says 1900 were dead and 9000 wounded, while on p. 118 she says 2000 were dead, 9000 injured, and 20,000 homeless -- which, if correct, means that more than half the city's population of roughly 50,000 was dead, wounded, or homeless. Very many of the injured lost their eyes to flying glass; 16 people lost both eyes, 249 lost one eye, and over 5500 had some sort of eye injury; 41 ended up totally blind (MacDonald, pp. 159, 234). The number of bodies was so large that, even when identifications had been made in the field, the information was often lost (MacDonald, p. 162).

Because the task was so great and the clues so few, very many bodies had to be buried before they were identified. Many of these, and some of the identified bodies from poor households, were buried in the same graveyard as the bodies brought in after the _Titanic_ disaster (MacDonald, pp. 244-245). Coffins were improvised in all sizes, with parts of bodies in some and multiple corpses in others (MacDonald, p. 248).

There were hundreds of orphans: some 70 children who lost both parents, and 200 who lost one or the other parent. Of the latter, about 110 had lost their mothers and had no father at home (usually because he was serving in the war); MacDonald, p. 232.

It is estimated that 2000 buildings were destroyed and 10,000 damaged, leaving 25,000 people with damaged homes.

In one way, recovery was surprisingly swift. The explosion took place on Tuesday. By the following Monday, the authorities were saying they did not need more medical people (a number of temporary hospitals were up and running), and most mail and gas service was restored (MacDonald, pp. 219-220). But it took several weeks to end food rationing, and families were given a food allowance even after that (MacDonald, p. 229). And rebuilding took far longer -- indeed, most permanent rebuilding could not begin until spring when the ground thawed (MacDonald, p. 237). Even today, anyone digging near the harbor will soon find many artifacts of the explosion (MacDonald, p. 276).

The damage was estimated at $35 million -- Canadian dollars, but 1917 Canadian dollars. MacDonald, p. 68, applied conversion factors to make this $420 million in 2004 U. S. dollars. I suspect even that is low. That's strict inflation, but buildings were proportionally cheaper back then (e.g. a house could be had for $4000). I suspect that it would cost several billion to build replacements in today's world.

Even as the burials were going on, an investigation was underway. It was not supposed to be a criminal proceeding, but the man in charge was a judge, Arthur Drysdale, and a witness said, "The setting was almost Dickensian" (MacDonald, p. 252). It was a difficult situation, with the public howling for blood, and there was also the problem that, while the pilot and master of the _Mont Blanc_ had survived, those on the _Imo_ were both dead (Glasner, p. 43, has a photo of the ship blown ashore; her masts survived but her upper works were "demolished"). It was difficult to reconstruct what the crew of the _Imo_ was thinking. MacDonald speculates that perhaps they failed to hear some of the whistle signals, but even seems insufficient.

MacDonald gives a detailed account of the proceedings (pp. 252-272), which ended with the blame being assigned almost entirely to pilot Mackay and master Le Medec of the _Mont Blanc_, plus the harbor Chief Examining Officer Frederick Evans Wyatt, responsible for procedures in the harbor.

We can't really know what happened. But, reading MacDonald, it appears to me that there were many mistakes, and the _Imo_ made all of them but the final one, when Mackay turned the _Mont Blanc_ hard to port to try to escape the coming collision and thereby caused it. Even there, he seems to have thought that was what the _Imo_ was calling for. It is clear that MacDonald considered Mackay a scapegoat, and Paine too is open to the possibility. Glasner, p. 121, makes it explicit: "A scapegoat was required, but Captain Haakon From [commander of the _Imo_] and [pilot] William Hayes were both dead. As a result, blame was placed squarely on the shoulders of the captain and pilot of the _Mont Blanc_ and Commander Wyatt.... Wyatt, Le Medec, and Francis Mackay were all placed under arrest and charged with manslaughter. Eventually, however, all charges were dropped."

The _Imo_, amazingly, was salvaged after the explosion, renamed, and put back in service -- but managed to wreck itself in the Falklands in 1921 (MacDonald, p. 282).

This song has all the features of a broadside prepared shortly after the explosion; I wouldn't be surprised if the author intended it to help the people raising money for relief. It includes the following accurate details:

"It was on the sixth of December, nineteen hundred and seventeen,

That Halifax suffered disaster, the worst she'd ever seen;

It was five minutes after nine, those still alive can tell"

The time of the explosion was December 6, 1917, 9:05 [a.m.].

"She carried a deck load of benzoil and shells for overseas,

In her hold a new explosive, they call it TNT."

Benzoil, or benzol, is the liquid fuel that caused the initial fire. The cargo was not shells, but shell bursters; close enough. The TNT, as we see above, was a relatively small part of the cargo (and not new; trinitrotoluene had been around for decades. But the Germans had used it first; it was a newer product to the British). But TNT was more famous than picric acid, even though less dangerous.

"Children were gone to their lessons, their mothers were busy at home,

While fathers worked on at the factories little dreaming they'd soon be alone."

Most of MacDonald's and Glasner's books are devoted to documenting where people were -- and, yes, it was an ordinary work day.

"The relief ship had rammed the monster tearing a hole in her side,

And eased out in the stream again and drifted on with the tide."

Obviously accurate from the account given above.

"Houses were crushed like paper, people were killed like flies,

The coroner's record tells us the toll was twelve hundred lives."

This would seem to imply the song was written very soon after the explosion, before the various missing could be tallied; 1200 is close to the number of actual bodies.

"Two thousand were maimed and wounded, hundreds more lost their sight

And God knows how many children were alone in the world that night."

This again implies composition soon after the event, since the number of wounded is low and the number of blinded slightly higher than the total who in the end were completely blinded.

"And then the following morning as if to hurt them twice

There came a storm from the ocean, a blizzard of snow and ice."

This obviously refers to the snowstorm that so hampered the relief efforts.

The major Canadian author Hugh MacLennan, who was a boy in Halifax at the time of the explosion, went on to make it the subject of his noteworthy first novel, _Barometer Rising_, published in 1941 (see Craig Brown, editor, _The Illustrated History of Canada_, Key Porter, 1987-2000, p. 417). - RBW

Historical references

  • Dec 6, 1917, 9:05 a.m. - The Halifax Explosion


  1. Laws G28, "The Halifax Explosion"
  2. Creighton-Maritime, pp. 208-209, "The Halifax Explosion" (1 text, 1 tune)
  3. DT 676, HALIFAXX
  4. Roud #2724
  5. BI, LG28


Author: unknown
Earliest date: 1933
Keywords: fire death disaster ship
Found in: Canada(Mar)