Approximately 160 residents at a North York seniors home won’t be able to return home Tuesday after a gas leak was detected in the building.

Crews were called to the complex at 1800 O'Connor Dr. near Victoria Park Ave., after members of the kitchen staff complained of feeling dizzy and nauseous. When firefighters arrived they detected high carbon monoxide levels and promptly evacuated the building.

“I was pretty scared. We were all pretty scared,” said Deborah Massie, whose father is a building resident.

Five staff members at the Leisureworld seniors home were taken to hospital as a precaution.

The residents have been transported to three other Leisureworld locations where they will stay until it is safe for them to return home.

“Until the investigation conducted by the Fire Department is complete, we are unable to confirm when our residents will be returning to our O’Connor Gate home. However, we are checking in with the Fire Department on an hourly basis for status updates. We will communicate the outcome of the investigation and next steps once it is complete,” said David Cutler, Leisureworld’s CEO in a statement.

While the building was equipped with carbon monoxide detectors, it’s unclear if they were functioning.

“My dad was awake from two o’clock in the morning. He said it did not go off And it’s pretty disturbing,” said Mike

“Every month we inspect the carbon monoxide detector…Maybe it’s not carbon monoxide. Maybe it’s something else,” said Peter Sigalis, director of engineering at Leisureworld.

Investigators say a roof heating unit is likely responsible, but that hasn't been confirmed.