The cause was found to be small fatigue cracks in the rails and joint bars, not detectable by the inspection routines then enforced by Canadian Pacific.
[2] Five tanker cars carrying anhydrous ammonia ruptured, releasing a cloud of caustic, poisonous gas over the city.
[3]: 11 Dispatchers told residents to close doors and windows, boil water, and cover their faces with wet cloths to counteract the ammonia.
The incident has been cited as an example of the physical dangers of media consolidation and the cost-cutting practice of not keeping overnight staff at stations.
[3]: 53 The NTSB found evidence at the derailment site of fatigue cracking on the rail and on joint bars used to connect sections of track together.
[3]: 69 The derailment made national news in the United States and Canada, though the CP involvement perhaps encouraged broader coverage in the latter.