To improve the air flow through the powerhouse temporary wedges were used to hold the fire doors open, but this compromised fire security. A permanent solution was implemented in 1999, when the wedges were replaced with electro-magnetic door retainers which combined with automatic door closers which hold the door open, but which in response to a fire alarm or a power failure automatically close the doors. Ventilation of the generator floor was further enhanced in 2002 by installing a ducted fan to import cool air from a dam drainage gallery.