Skip to Main Content. District Home. Select a School Select a School. Sign In. Search Our Site. Carbon Monoxide. What is carbon monoxide? Carbon monoxide CO is a non-irritating, odorless, colorless gas that is somewhat lighter than air. A by-product of incomplete burning of coal, wood, charcoal, natural gas, fuel oil, kerosene, gasoline, fabrics and plastics, it is the leading cause of poisoning deaths in the United States.
Because the burning of fossil fuels and fossil fuel products is so widespread, CO is a common air pollutant, particularly in urban areas. Elevated levels in cities are caused by the concentration of traffic, industry and heating needs.
Indoors, elevated CO levels can be traced to gas appliances, tobacco smoke, or poorly vented or unvented combustion sources. Automobile exhaust combined with inadequate ventilation is responsible for two-thirds of all accidental CO deaths. Lethal levels of the gas can occur in as little as 10 minutes in a closed garage. People in certain occupations, including highway workers, traffic officers, tunnel workers, professional drivers, toll booth attendants and warehouse workers, are exposed regularly to high levels of CO.
Indoor events, such as tractor pulls, car and truck exhibitions, or ice hockey or skating, can expose spectators and participants to elevated CO levels if these areas are not adequately ventilated. Faulty heating equipment accounts for nearly one-third of accidental CO fatalities. Culprits can include your home heating system, but also improperly vented or unvented gas appliances, kerosene or propane space heaters, charcoal grills or hibachis, and Sterno-type fuels.
Fires can raise CO levels in the blood of unprotected persons to times normal in one minute; CO poisoning is the most frequent cause of immediate death associated with fire. Smoke given off by cigarettes also can cause elevated CO levels in both the smoker and nonsmokers who are exposed to the smoke.
