A gas explosion in a London tower blew out a wall — and the whole corner collapsed

Ronan Point was a 22-story apartment tower in Newham, London, built using a 'system-built' large panel construction method — precast concrete walls and floors stacked like a house of cards. The building was part of a wave of affordable housing built in the 1960s using industrial methods. The system was fast and cheap, but had never been tested for gas explosion resistance.

On May 16, 1968, a gas explosion in the 18th floor kitchen blew out an external load-bearing wall panel. The floor above was left unsupported, collapsed, and the failure cascaded down — the entire southeast corner of the building collapsed. Four people were killed and 17 were injured. The damage was contained to one corner, but the building was structurally compromised.

The investigation found that the panel construction system lacked robustness: the joints between panels were not strong enough to transfer loads after a local failure. The building had no secondary load paths — if one panel failed, the structure above had nothing to hold it. The collapse led to changes in British building codes, requiring that buildings be designed to withstand a local failure without disproportionate collapse.