We have a lot of small ones from the centuries of occupation.

We were the main Atlantic port of entry until airlines took over. We have always been a strategic port and until the late 1800's we weren't sure the British were gonna hold it. We don't have a harbour lined with gun emplacements because it was uncontested.

Also Lawlor Island was the quarantine location.

Add to the fact that Halifax has a terrible ability to plan fucking anything. There are new subdivisions that don't have proper fire fighting infrastructure (not old ones either).

This wouldn't have anything to do with it, would it? Halifax Explosion