Fire officials are warning homeowners to make sure they have working carbon monoxide detectors in their homes after a propane heater caused carbon monoxide to reach near deadly levels in one central Ottawa home, sending two men to hospital.

Firefighters discovered the alarming levels of carbon monoxide when they were called to a two-storey house split into three apartments on Bell Street in Centretown at about 8 p.m. Tuesday.

Officials say the levels of carbon monoxide in the building were found to be 10 times greater than what is considered safe, and could have become deadly within three hours.

Two men, aged 46 and 47, were suffering from carbon monoxide poisoning. They were treated by paramedics and taken to hospital.

Fire officials say a propane heater used to defrost frozen pipes seemed to be the cause of the problem.

One tenant told CTV Ottawa her unit had been without heat since Saturday, and her landlord was working on the problem.

She said she had a horrible headache, but didn't realize it was a sign of carbon monoxide poisoning.

The landlord said the building's furnace broke down over the weekend, and he was waiting for Direct Energy to fix it.

Meantime, he gave his tenants electric heaters, and put a propane heater in the basement.

An Ottawa lawyer says the landlord could face serious charges, especially if the carbon monoxide caused harm.

"When something breaks down, it's ultimately the landlord's responsibility to respond to it," said Blair Crew, a law professor at the University of Ottawa.

Firefighters have since vented the building, which is now free from carbon monoxide.

The dangerous, colourless and odourless gas can escape from faulty furnaces, heaters, wood stoves and vehicles that are left running.

"If you have a gas or wood stove in the house, if you heat by natural gas or oil, then there's a potential for carbon monoxide in the house," said Arthur Herscovitch, who is a fire prevention officer with Ottawa Fire Services.

"If you do not have any of those, and just heat by electricity, then there's no need for carbon monoxide detectors or alarms in the home."

Firefighters recommend having carbon monoxide detectors on every level of your home, especially near bedrooms. Those detectors should be checked often, and batteries should be changed twice per year, along with the batteries in your smoke alarms.

Symptoms of carbon monoxide include:

  • headache
  • nausea
  • and disorientation

Carbon monoxide poisoning can eventually lead to unconsciousness, and even death.

If you think you are suffering from carbon monoxide poisoning, you are advised to leave the premises immediately, and call 911.

Ottawa Fire Services also offers a free program to seniors who need to get their carbon monoxide detectors checked or installed.

The program, called "project zero", will even install carbon monoxide detectors for seniors for free. Those who want to sign up for the program can contact Ottawa Fire Services at 613-580-2860.

With a report from CTV Ottawa's Kristy Kirkup