Saint John's city lockup occupied the ground floor of City Hall, an arrangement that dated to an era when municipalities saw nothing unusual about housing prisoners directly beneath the offices of elected officials. The cells were not designed for extended stays. They served as overnight holding pens for people awaiting court appearances or sobering up after an arrest. By 1977, though, conditions in the lockup had drawn criticism. The cells featured padded walls, a detail that would become central to the investigation that followed. Critics later charged that the padding material was highly flammable, turning each cell into a potential fire trap. Ventilation was poor, sight lines were limited, and the physical layout made rapid evacuation nearly impossible.

John Edward Kenney, a 27-year-old prisoner, started the fire. How he managed to do so remains one of the incident's most troubling details: police officers had searched him twice for matches before placing him in the cell. Despite those searches, Kenney obtained or concealed the means to ignite the padding material in his cell. The fire spread with devastating speed. Thick, toxic smoke filled the confined space before guards could mount an effective response. The layout of the lockup, with its narrow corridors and locked doors, turned the holding area into an inescapable chamber. Twenty-one men died, most from smoke inhalation rather than burns. Kenney survived and was later convicted.

The roster of the dead intensified the public's grief and anger. Many of the 21 victims had been brought in on charges that carried no prison time at all: public drunkenness, minor disturbances, the kinds of offences that might result in a fine and a lecture from a magistrate. These were not violent criminals. They were ordinary men whose worst decision on a summer evening was having one drink too many. Research conducted decades later revealed that at least one of the dead was a decorated war veteran. The disconnect between the triviality of the charges and the finality of the punishment was impossible for the public to accept. Families demanded answers about why their fathers, brothers, and sons had been locked in a facility that could not protect them from a fire.

The fire forced a reckoning with how Canadian municipalities housed people in short-term custody. Investigations focused on the flammability of cell padding, the adequacy of fire suppression systems, the procedures for searching inmates, and the broader question of whether minor offenders should be jailed at all. Saint John City Hall still stands at 15 Market Square near the foot of King Street, a modernist 17-storey tower built in 1971 that gives no outward sign of the tragedy that unfolded in its lower floors. For the city, the fire remains a painful chapter, one that reshaped how New Brunswick and other provinces thought about the duty of care owed to people in even the briefest forms of custody. Memorial efforts in later decades sought to restore the names and stories of the 21 men who did not walk out of that lockup.