Hydro One says a broken insulator likely caused lights to flicker across Ontario on Monday night.
The utility says a momentary issue on its transmission system resulted in a voltage disturbance at approximately 9:26 p.m. on Monday.
It says the cause is still under investigation, but reports suggest an insulator, the piece of equipment that holds a power line off of a transmission tower, broke and caused a transmission line to fall to the ground.
Hydro One says the line also made contact with another transmission line as it fell in a parking lot in west-end Toronto.
Hydro One says it's investigating what role weather and salt contamination might have played in causing the insulator to fail.
Hydro One proactively monitors and mitigates salt contamination through power-washing, but says its efforts have been hampered this year due to extreme and prolonged cold temperatures.
No injuries have been reported, and there were no power outages as result of the incident.
