12/20/2011 12:17 EST | Updated 02/19/2012 05:12 EST

CO leak at Toronto nursing home

About 150 residents of a Toronto seniors' care facility will have to spend at least one night away from their homes following a carbon monoxide leak.

The earliest they'll be allowed back is Wednesday morning.

Five people — all staff working in the kitchen at Leisureworld at 1800 O'Connor Drive — were treated on Tuesday morning after complaining of illness.

"Initially the call was made to us from four kitchen staff who were experiencing nausea and dizzy symptoms," said Capt. David Eckerman.

When firefighters arrived at about 11 a.m., as a precaution, they decided to clear the home.

"Toronto Fire Service decided to err on the side of caution and evacuate the entire building," Eckerman said.

Readings 40 times acceptable limit

Firefighters discovered carbon monoxide readings more than 40 times the allowable limit.

An acceptable level of carbon monoxide is between 0 to 10 parts per million. But Air monitor readings showed samples that were between 300 and 400 parts per million.

"At that high level, unconsciousness could occur very quickly in a confined-space environment," said EMS commander Peter Rotolo.

"If this had occurred [at] 3 in the morning, we'd have other issues. We certainly don't want to go there."

Firefighters ventilated the building and called in experts to try and discover the source of the leak.

Enbridge, the Technical Standards and Safety Authority and Toronto Fire are investigating the cause of the leak, which appears to have started in the heating system filtered into the kitchen area.

Alarms didn't sound

Peter Segalis, who works for Leisureworld's head office, said the buildings are equipped with carbon monoxide detectors, but said the alarms didn't sound.

Rita Davis, a resident in the seniors home, said people were "huddled up there" but that no alarm had gone off when the residents were evacuated from the building.

Her son, Wayne Davis, lives nearby and came to see how his mother was faring when he heard the sirens.

"She was a little upset but she's calm now," he said.

Elizabeth Giles, who was in the seniors home to visit her 87-year-old father, said she didn't hear an alarm either. She described a scene of chaos when the residents were rounded up and told to leave as quickly as possible.

"People were crying and people didn't know what was happening," Giles said. "People being pushed out in beds, and they were throwing blankets around people, and it was like bumper cars in the hallway."

Some of the elderly residents are being taken to the homes of relatives where they'll spend the night.

The seniors were kept warm in TTC buses. Some were taken to another building in the complex to wait for the all-clear.

There were no reports of any of the residents falling ill, and no reports of injuries.