The Consumer Product Safety Commission says that carbon monoxide (CO) is the number one cause of fatal poisonings in America; however this data is somewhat misleading because it includes suicides, usually from auto exhaust fumes inside an enclosed garage.
The characteristics that make CO a favored method of taking one’s own life are the same that make it such an insidious danger to people not so inclined. It is a tasteless, colorless and odorless gas. People can succumb to it with very little physical discomfort, almost like falling asleep.
At exposures in the range of 10%, CO poisoning can give symptoms of fatigue, dizzy spells, headaches and nausea. Often people sickened by CO think they have the flu or food poisoning, and it is easy, even for medical professionals, to misdiagnose the symptoms. Exposure to levels of 40% CO, and more, can lead to brain damage and death.
CO is given off by incomplete combustion of flammable fuels such as natural gas, oil, wood, coal or kerosene. Under normal circumstances the main by-products of combustion are carbon dioxide (CO2) and water vapor, substances normally exhaled when we breathe. However, when there is inadequate air to support combustion, it produces less CO2 and more CO, which instead of being exhaled, is absorbed into the body through the lungs and deprives the body tissues of oxygen.
Common household appliances such as furnaces, boilers, water heaters and stoves are all potential sources of CO gas. All of these products were designed with elaborate safeguards and under normal operation conditions the CO produced from combustion will be harmlessly vented to the atmosphere. Leaks or blockages in the vent system are the most common way for CO to back up into a dwelling space. Cracks or corrosion in a furnaces heat exchanger also can lead to danger.
Our national quest for energy efficiency has substantially elevated the hazard of CO poisoning. Tightly insulated modern homes trap exhaust gasses inside. Also, the more efficiently burning furnaces and boilers of today contribute indirectly to greater CO hazards. For instance, high-efficiency heating units produce a greater amount of condensate in the flue system. This condensate is highly acidic and over time, eats away at chimney masonry and metal piping components of the flue system, leading to crumbling that may block the exhaust passage.
There are a number of CO detection devices now on the market. At the low end of the scale are chemical patches that you can buy for under $10 that change color in the presence of CO gas. Unfortunately, they also react with many other substances, leading to a large number of false positives.
At the other end of the spectrum are ultra-sophisticated professional CO detectors that sell for around $800. In between are a variety of alarms on the market that operate much like smoke detectors. They generally sell in the $50-100 price range. Some, but not all, are UL-approved, an important consideration for anyone looking to buy one.
CO detectors have not yet reached anywhere near the degree of consumer popularity as smoke alarms. This may change as prices come down and local governments begin mandating them.
There are some industry professionals who maintain that the CO danger is blown out of proportion, and that relying on detection devices for protection may be counter-productive. While deadly, CO poisoning is far less common than the number one cause of home fatalities and injuries—fire. Also, CO detectors may provide a false sense of security. Any detection device can malfunction and even the most reliable CO alarms can be misled if put in the wrong location.
Ultimately, there is no better way to guard against the hazards of CO than to have your heating system inspected at least once a year by a competent professional who can spot danger signs and make repairs before they become life-threatening.
Kevin Shaw Plumbing, Inc. & Nexstar Network