1896 Brunner mine accident

At 9.30 a.m. an explosion was heard from the Brunner mine in Westland's Grey Valley. Two men sent to investigate were later found unconscious from black damp, a suffocating mixture of nitrogen and carbon dioxide. By 11 a.m. rescuers began bringing out bodies. Those involved in the rescue very nearly became victims due to the noxious gases and had to be carried out. A total of 65 miners were killed by the choking gas – almost half of Brunner's underground workforce. This remains New Zealand’s deadliest industrial accident.

The official enquiry determined that the cause was the detonation of a charge in a part of the mine where no one should have been working. Some experienced miners disagreed with the findings. They maintained that firedamp – methane gas produced by coal – had accumulated and not been cleared due to an ineffective ventilation system.