A bill that would require all homes to have CO alarm cleared its first test Tuesday, passing by a whisker out of a Senate committee.

Senate Bill 187, by Sen. Bob Hagedorn, D-Aurora, would require carbon-monoxide alarms in new homes and also in existing homes when they are sold. The requirement would apply to apartment buildings and condominium complexes as well.

Hagedorn said the alarms can provide vital warning of a carbon monoxide buildup in a home, which kills several people in Colorado each year.

"It's a silent killer," said Fort Collins resident Robert Reyes.

Reyes said he and his family woke up seriously ill from carbon-monoxide poisoning one morning two years ago. They spent most of the day in the hospital and, upon being released, bought an alarm for their house.

That alarm notified them of another dangerous buildup in the home several months later.

In the committee hearing, representatives from several realty and homebuilding-related associations spoke against the bill, saying CO alarms are unreliable. They will sometimes sound false alarms and, at other times, fail to go off when carbon monoxide reaches dangerous levels, said Greg Wheeler, from the Colorado chapter of the International Code Council, a building-safety organization.

"Co Detector are not ready for prime time and should not be mandated," Wheeler said.

The committee approved the bill 4-3. It next goes to the full Senate.