FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

INVISIBLE KILLER SKULKING ABOUT HOMES AND BARNS

Question: On bitterly cold nights we use a kerosene heater in our house to supplement the heat from our old furnace. How great is the risk of carbon monoxide poisoning from doing this?

Answer: Hooray! You are thinking about safety, and that is the first step toward having a safe home. Carbon monoxide is an invisible and odorless gas. It is produced when hydrocarbons, such as the kerosene in your heater or wood in your fireplace, are incompletely burned. Under ideal combustion the larger carbon-containing molecules of fuel are broken down and chemically bonded with oxygen obtained from the air. This forms carbon dioxide, that is known by its chemical formula CO2. Carbon dioxide poses no health hazards for humans when the concentration is low. However, its chemical "cousin" carbon monoxide, CO, does present serious health problems.

Carbon monoxide causes problems at very low concentrations because of a peculiar feature of our hemoglobin, the oxygen carrying part of our blood. Hemoglobin's chemical affinity for carbon monoxide is so strong that it prefers to chemically unite, or "bind," with it instead of oxygen. As an example, exposure to carbon monoxide at a concentration of one molecule per million molecules of air for one hour will result in 80 percent of the blood's hemoglobin being bound with CO. This leaves only 20 percent of the hemoglobin to carry oxygen to all the body's parts a serious condition requiring immediate medical attention to save the individual's life.

Kerosene heaters are efficient and produce little carbon monoxide, but little isn't none. So, these heaters should not be used in a closed space like a home without added ventilation. It is essential to have some open windows so that there is fresh air coming into the building. When using a heater like this, your home should feel warm but with cool drafts of outside air. If you don't have the drafts, you are at risk of carbon monoxide poisoning.

People die of carbon monoxide poisoning every winter. Blizzards seem to make the risks particularly high. There are probably several contributing reasons for this. The blizzard often produces loss of electrical power, so people get out their kerosene heaters to stay warm. Another factor is that the blowing snow tends to seal up the little crevices and passages that allow air to pass between inside and outside environments. The result is a house that has less air exchange to dilute the deadly carbon monoxide.

Question: What are other sources of carbon monoxide in the home?

Answer: A leaky furnace or fireplace flue can let carbon monoxide into your home instead of venting it outside. To reduce your risk of this, I'd recommend that you have your furnace and fireplace inspected every year by your furnace dealer.

While I was reviewing the medical literature in preparation for this column, I discovered a risk that surprised me power washers. Yes, those gasoline-powered devices that spray high-pressure water and look something like the "washing wand" at self-service car washes.

Power washers were responsible for two deaths and numerous hospitalizations last year, with a disproportionate number of the victims being farmers. This is because many farmers apparently use power washers to clean livestock barns, particularly pig barns. This is OK, but the power unit should always be left outside the building. If the power unit is inside, exhaust fumes from the gasoline engine may be trapped in a poorly ventilated barn, and carbon monoxide can reach dangerous levels.

You can't count on warning labels to remind you of these dangers, but there are two important ways to protect yourself from carbon monoxide build-up in your home. First, be sure to have adequate ventilation in any area where you use carbon monoxide-producing equipment. Second, this odorless, invisible killer can be detected by special cards that change color in the presence of dangerous levels of carbon monoxide. Contact your local branch of the American Lung Association about the availability of these in your area.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.