Some security companies are changing the way they do business after a deadly basement fire.

Early Monday morning, four people were left unconscious after a fire broke out in a basement suite. Two of the victims died and two more are still recovering in hospital.

A space heater caused the blaze and fire officials are investigating whether, or not, security bars on the windows prevented the victims from escaping.

Calgary Lock & Safe says since the fire they have had lots of calls about window security bars. "Because of the news, they're all asking for breakaway bars solely, the do not want to have fixed bars," says Rheal Cinq-Mars.

Cinq-Mars says from now on, his company is only selling quick-release bars. "Window bars that we put on normally had padlocks on them for security, or they were fixed, and we found....this is probably not a good policy for out company to put these on basement windows."

Investigators have not yet said if the window bars in the basement fire were permanently in place or just locked.