The 1917 Halifax Explosion was an unfortunate but predictable tragedy, given the sea traffic and munitions cargo, resulting in sudden large-scale damage and catastrophic injuries, with 1950 dead and 8000 injured. Although generous support was received from the United States, the bulk of the medical work was undertaken using local resources through an immediate, massive, centrally coordinated medical response. The incredible care provided 100 years ago by these Canadian physicians, nurses and students is often forgotten, but deserves attention. The local medical response to the 1917 disaster is an early example of coordinated mass casualty relief, the first in Canada, and remains relevant to modern disaster preparedness planning. This commentary has an appendix, available at canjsurg.ca/016317-a1.