Hydro-Quebec is still investigating why a contractor severed a power line that cut electricity to 275,000 Quebecers yesterday.
Hydro said it's currently speaking to the workers who were doing maintenance at the east-end Bout-de-l'Île substation.
While both internal and external contractors were on the job, it was an external contractor who accidentally cut the power line that provides electricity to most of the northern and eastern parts of the island.
Hydro wants to know exactly why it happened so it can prevent it from occurring again.
The power outage knocked out traffic lights and shut down the metro's blue line at the end of the morning rush hour.
Hydro eventually restored power by the middle of the afternoon.