Carbon monoxide poisoning kills hundreds of people each year in the U.S. This poisonous gas is invisible and odorless, and so you cannot hear, taste, see or smell it. Many of its victims are individuals or entire families who, although they are aware they don't feel well, by the time the gas has taken effect they are disoriented and unable to save themselves. Young children and pets are usually the first affected by this killer.
As of April 1, 2012, Washington's RCW 19.27.530 requires all sellers to have operating carbon monoxide alarms installed in accordance to the state building code before a buyer or any person can legally occupy the residence following the sale. The building code (WAC 51-51-0315) requires alarms to be installed:
1) outside of each separate sleeping area in the immediate vicinity of each bedroom;
2) on each level of the dwelling; and
3) in accordance with the manufacturer's recommendations.
The building code also requires that the alarms comply with UL 2034. There are no exceptions to this, and they may be electric or battery operated.
In addition, a property owner must install carbon monoxide alarms when performing any remodels, repairs or additions to their dwelling that require a building permit. (New construction has been required to have carbon monoxide alarms installed since January 2011.)
At times during power outages in cold weather, unsuspecting homeowners will operate propane heaters or barbeque grills inside in an effort to stay warm. One of the byproducts of this combustion is carbon monoxide. This can, and does, poison entire families while they sleep. Do not EVER use propane heaters or wood stoves without proper ventilation to the outside!
The alarms are triggered by carbon monoxide levels below those that can cause loss of ability to react and prevent death from exposure to this poisonous gas. Small children and pets will display symptoms before adults, so be aware if they suddenly start acting ill. Immediately open windows and exit the house, then call the police. Do not re-enter the building until the source of the gas has been eliminated.