The Invisible Hazard: Carbon Monoxide Poisoning
The second acute hazard—carbon monoxide poisoning—is the most significant. This hazard is not common to all heating equipment. It is unique to unvented (or improperly vented) space heaters fueled by gas (or, to a lesser extent, kerosene). Carbon monoxide poisoning can occur if the heater's burner is maladjusted or if the heater is used without adequate ventilation. The hazard is particularly ominous because carbon monoxide is odorless and colorless—you can be poisoned without knowing it, especially if you are asleep. Most deaths appear to be caused by inadequate ventilation, and apparently most of those are in bedrooms. It seems counterproductive to many consumers to open a window while heating a room, but ventilation is required to ensure safe use.
The carbon monoxide hazard is well recognized but poorly documented. Industry trade associations do not collect injury data in any systematic way. Representatives on the relevant AGA committees are aware of the common hazard scenarios, sometimes as a result of newspaper clippings sent to the committee. But the problem is not widely discussed, and anecdotes are not freely exchanged during the standards setting process.
The CPSC is the only organization that has attempted to quantify these hazards, relying on files of death certificates, reports from hospital emergency rooms, and its own in-depth investigations. The CPSC placed the unvented heater fifteenth on a list of over 350 hazardous consumer products. Except for possible publicity value, however, this designation is of dubious assistance to the agency's regulatory effort. More pertinent than the total number of injuries is the character and seriousness of various components of the injury problem. How many cases of carbon monoxide poisoning occur? What are the causes and possible solutions?
Epidemiologists at CPSC have reached two relevant conclusions. The first is widely accepted: contact burns are the most common hazard associated with the unvented heater. Four-fifths of reported injuries are contact burns; the majority of these are children and elderly people who fall against the heater. The second conclusion is more controversial:
unvented heaters are responsible for some seventy carbon monoxide deaths per year. This number has appeared repeatedly in briefing papers and newspaper articles over the past ten years, although its origin and accuracy are unclear. Still, the number emerged with what Max Singer has dubbed "the vitality of mythical numbers.