The small canister of propane would not have exploded so quickly. It would have at least taken 10 minutes to heat up enough to detonate. Even then, the explosive energy would have been directed (by the 55-gallon drum it was in) straight up. There certainly would not have been enough explosive energy to break the fence.
The city of Caraquet in New Brunswick is an entirely French community - it seems unlikely that none of the people who survived had French accents.