mt kembla coal and oil company's mine in kembla heights was the site of the worst industrial accident in australia's history, the mt kembla mine disaster. the disaster took place on thursday 31 july 1902, at precisely three minutes past two o'clock in the afternoon. the disaster was caused by gas seeping undetected from the coal seam in a disused area of the mine that had been mined out. a rock fall pushed the gas out into the tunnels where men were working. when the gas reached the naked flame of colliery workers light, it ignited instantly and caused a series of further gas and coal dust explosions. the initial blast killed some instantly, but the majority died from carbon monoxide poisoning which penetrated the tunnels from the incomplete combustion of fuel.