Firefighters respond to smoke from a grate outside Southam Hall. (Photo by Shamit Tushakiran)

UPDATE: The fire was in an air-handling unit that brings air in and out of the building. The fire was contained within the unit, and it appears it was started by a cigarette thrown into the grate, according to Allan Burns, director of university safety. No one was injured.

Southam Hall was evacuated this evening after smoke started billowing from a grate just outside its main south entrance facing the Loeb Building around 5 p.m.

Three Ottawa fire trucks responded to the smoke.  Firefighters hosed down the grate until the smoke disappeared.

The cause of the fire remains unknown, but Southam Hall was safe to re-enter as of 5:30 p.m., according to the department of university safety.

The grate connects to the tunnels, according to a Carleton safety officer on the scene. There was a slight burning smell when entering Southam Hall through the tunnels.

— with files from Jakob Kuzyk