"A Code Orange is an international code used to signal a catastrophe or external emergency that requires the mass transportation of casualties to hospitals", said Michel Garceau of Montreal's health and social services agency in a news release.
"The simulation is very important since it will help improve practices already in place," he said.
The simulation exercise also involved Jean-Talon and Hôtel-Dieu hospitals.
Similar exercises were held in October 2012 and 2013.