"University Bridge" by Brandon Giesbrecht is licensed under CC BY 2.0.

Fire investigators have determined that the fire that melted sanitary sewer lines under University Bridge near Spadina Crescent was human caused.

Crews were called in around 3:41 p.m. Sunday and worked through the night to repair damage to the sewer line, caused by a small fire.

All four lanes of traffic on the University bridge are open; however, the City says there is still a restriction in the westbound curb lane at the top of the University Bridge to make room for a pump connected to a sanitary sewer bypass line on the north walkway which is closed. Westbound drivers are reminded to use both lanes and zipper merge or re-route their commute if possible.

The City suspects traffic restrictions will remain in place for the rest of the week as repairs continue. Crews are currently cleaning up frozen wastewater that spilled out of the damaged sanitary sewer line.

On the bright side, the bridge was inspected and no structural damage was found, and the south pedestrian walkway remains open.