"Carbon monoxide is produced when a fuel, like natural gas, propane, fuel oil, wood, charcoal or gasoline, is burned. It can leak from faulty or poorly maintained fuel-burning appliances or can enter the house because of a blocked chimney or flue that hasn't been cleaned," said Donna Chilton, environmental design specialist, University of Missouri Outreach and Extension.
Well-maintained equipment and applications, safe operation and the installation of carbon monoxide detectors will help prevent accidents and save lives.
According to Chilton, carbon monoxide detectors should meet Underwriters Laboratories (UL) standards, have a long-term warranty and be designed so they can be easily self-tested and reset to ensure proper functioning. The best place for a carbon monoxide alarm is near sleeping areas.
"Carbon monoxide is a colorless, odorless and tasteless poisonous gas that interferes with the blood's ability to carry oxygen. Low-level exposure to carbon monoxide can cause symptoms such as headaches, dizziness, weakness, nausea or loss of muscle control. Concentrations above 800 parts per million can cause unconsciousness after one hour and death in two," said Chilton.
Chilton says all home fuel-burning equipment (like furnaces, chimneys and flues) should be inspected annually to ensure proper ventilation and efficient operation.
"It is also important that all fuel-burning heaters used to warm the house be vented to the outside. If you must use an unvented heater, leave a window (in the same room with the heater) open at least one inch. Unvented heaters should be turned off at night," said Chilton.
Install exhaust fans over gas cooking stoves and ranges to vent the fumes outdoors to reduce pollutants during cooking.
"Don't use ovens or gas ranges to heat your home, even during an emergency," Chilton said.
She also recommends not closing all foundation vents under the house when heating equipment - like floor furnaces and central-heating systems - are located under the house.
Another common source of carbon monoxide is backdrafting. Fireplaces and woodstoves should have a dedicated outdoor air supply to prevent backdrafting into the living space. Chilton says that with both gas and wood fireplaces, it is important to always make sure the flue is open when the fireplace is in use.
"In airtight houses with a number of combustion appliances that use house air to supply the fuel burners, chimney backdrafting can occur as a house becomes depressurized from exhaust fans, a fireplace or from competition for air among other combustion appliances," said Chilton.
According to Chilton, it is also important to never use a charcoal grill indoors (burning charcoal gives off a large amount of carbon monoxide) and to never run an automobile engine continuously in an attached garage without proper ventilation.
For more information about carbon monoxide and other combustion gases, look for a copy of guide sheet GH5001, "Indoor Air Quality" here.