Flame-Sterilizing Fire Incident

A fire occurred when a lab worker was flame-sterilizing slip-glasses. The slip-glasses were in a small container of ethanol inside a biosafety cabinet. The slip glasses were being removed, one at a time, with tweezers as the employee held each one in the flame of a small gas burner unit and then placed in a holder.

The employee could not see flames but noticed heat emanating from the supply container holding the unsterilized slip-glasses. She attempted to extinguish the fire by placing an aluminum-foil cover over the container because the container’s cover was not available. The aluminum foil cover blew off, so the employee attempted to cover the container with a petri dish. However, a pipetter in the cabinet had caught fire, probably due to ethanol spilling into heat-induced cracks in the container.

She went for a fire extinguisher, only to find upon return that the door to the room had shut and was locked. She did not have the key. At this point the employee called 911 and activated the building fire alarm system. Damage was limited to the interior of the biosafety cabinet and the pipetter. The employee’s actions in response to this incident were admirable. She initially attempted to extinguish the fire; when unable to do so, she called for additional help. The only improvement would have been if someone else had been able to call 911 and activate the fire alarm while the first employee was still trying to extinguish the fire. This fire was probably started by an invisible burning drop of ethanol falling into the supply container.

The lessons to be learned for anyone doing similar work are: 

  • Position the container of ethanol, supply of slip-glasses and the destination container so that there is no potential for carrying the sterilized slip-glasses over it  

  • Be sure to have a key on your person at all times for any room in which you’re working whose latch is set to lock every time the door is closed.