The explosion came at approximately 11:37 p.m. Atlantic Standard Time on January 4, 1974. The Irving Reversing Falls Service Station was one of Irving Oil's major outlets in Saint John, positioned at a natural bottleneck of the city's geography -- the eastern approach to the bridge that crosses the famous Reversing Falls, where the Saint John River meets the Bay of Fundy. On a winter Friday night, three gas station employees were on shift: Kenneth Ernest Dunham, David John McLaggan, and Aubrey Eugene Johnson. Lunn and his co-worker William M. Corner were with the truck. All five were caught in the blast.

The sequence of events was grimly mechanical. The tractor-trailer's contact with the pump sheared it from its mounting. Gasoline, under pressure in the fuel lines, began flowing freely. The station's basement had unsealed openings beneath the pump dispensers -- gaps that under normal conditions posed no obvious hazard but that now acted as channels, funneling liquid gasoline into an enclosed underground space. Gasoline vapor is heavier than air. It sank into the basement and accumulated, invisible and lethal, until it reached a concentration that needed only a spark. The resulting explosion was not a slow burn but a detonation, and it leveled the service station entirely.

Kenneth Dunham, David McLaggan, and Aubrey Johnson were working their shift. Ivan Lunn was driving his truck. William Corner was riding along. None of these men did anything wrong -- a truck maneuvering in a service station, employees doing their jobs on a winter night. The explosion killed all five. Six other people were injured but survived. The victims were ordinary working people in an ordinary place, and the randomness of the tragedy -- a truck turning a few degrees too sharply, a pump mounted a few feet too close to the truck's path -- is what makes it linger. David McLaggan's family would carry his memory for decades. In 2020, a CBC News story reported that a classic Fender guitar he had owned found its way back to his family by chance, a small thread of connection across forty-six years.

The Reversing Falls Service Station continued operating after being rebuilt, but it eventually closed in September 1998 -- a quiet ending for a place marked by tragedy. The Reversing Falls themselves remain one of Saint John's defining landmarks, the point where incoming Bay of Fundy tides force the Saint John River to reverse its flow through a narrow gorge. The bridge at the eastern end, where the station once stood, still carries traffic across that gorge. Nothing at the site today marks what happened on that January night in 1974. The geography endures -- the river, the falls, the bridge -- but the human story has largely passed from public memory, preserved in newspaper archives and in the families who lost someone when a routine fuel stop went wrong.