The Royal Commission inquiry into the Pike River mine disaster heard on Thursday that a vertical ladder in the mine would have been almost impossible to use as an exit in a fire.
The commission is in its ninth day of a hearing in Greymouth into explosions at the West Coast mine, in which 29 men died last November.
A lawyer assisting the commission, Simon Mount, asked Pike River coal company chief executive Peter Whittall how miners would get out in an emergency.
Mr Whittall said the primary exit was the tunnel, and there was an emergency exit via a 100 metre vertical ladder through the air ventilation shaft but this was not deemed to be the secondary exit. Miners were instead told to go to a fresh air safety chamber in the mine.
Mr Mount said a 2009 report by the Mines Rescue Trust found that in the event of fire, the vertical escape ladder would have been virtually impossible to use. He also said the chamber provided no way out of the mine.
Mr Whittall said to his knowledge there had been no trial evacuation of miners up the emergency ladder.