Guests at the Days Hotel and Conference Centre on Yorkland Boulevard, near Highways 404 and 401, have been allowed back into the building after they were evacuated because of a gas leak scare. 

The Toronto Fire Service was called to the scene shortly after 11 a.m. Emergency crews checked two small boilers in the basement and found an exhaust vent had malfunctioned.

Fire Capt. David Eckerman, a spokesperson with TFS, told CP24 that the gas levels started dropping as soon as the boilers were shut off. However, there were traces of carbon monoxide in the air.

"Natural gas isn't as much a poison as it is a concern because it displaces oxygen," Eckerman said.

Enbridge workers repaired the vent and the hotel was ventilated before guests were allowed back in.

The 40 or so displaced guests were shelted from the bitter cold in heated TTC buses while emergency crews investigated the situation.