By Olivia Rose-Innes
It could be called the “suicide gas”: each year thousands of people deliberately inhale it, usually in the exhaust fumes of their own cars.
But carbon monoxide (CO) has also caused more accidental deaths than any other poison in history – not just because it’s deadly, but because it slips under the radar of the human senses: you can’t see, smell or taste it, and it doesn’t irritate the skin or mucous membranes.
And it’s fast-acting. By the time you notice symptoms of poisoning, it’s often too late.
Common carbon monoxide sources
Carbon monoxide is produced as a result of the incomplete combustion of any carbon-based fuel (petroleum, gas, paraffin, oil, coal, wood, charcoal, etc).
Combustion produces other toxins too, but none as lethal as CO. When people die of smoke inhalation during fires, it is again CO that is the primary killer.
Thus potential sources of dangerous CO levels include motor vehicle exhaust fumes, and the combustion fumes from fuel-burning appliances – such as charcoal braai grills, camping stoves, fireplaces, gas stoves and heaters, wood and coal ovens, and petrol generators and power tools.
When these appliances are kept in good working order and used correctly with sufficient ventilation, they don’t carry a high risk for CO poisoning. But faulty appliances used in enclosed (or even semi-enclosed) spaces, for example a charcoal braai grill burning in the kitchen or a car engine running in a closed garage, can cause CO to build up to fatal levels.
Generators a life-threating hazard
Occupational Care South Africa (OCSA) is concerned that power outages in recent years led to many members of the public purchasing generators - a purchase that introduces a life-threatening hazard into the home or workplace.
In its safety advisory on the issue, OCSA points out that: “A generator's exhaust contains poisonous CO which can kill you in a matter of minutes.”
Symptoms of carbon monoxide poisoning
Low levels of CO poisoning are often mistaken for those of other common ailments, like ‘flu, and may include: headache, dizziness, nausea, fatigue, weakness and shortness of breath. You can strongly suspect CO poisoning if these symptoms improve when you go outside.
With higher levels of poisoning, symptoms become more severe, and include worsening headaches, vomiting, fainting, confusion and impaired vision and hearing.
At very high levels, CO causes loss of consciousness, coma and eventually death.
Symptoms can occur within minutes of exposure to the gas, and you can succumb to its effects before you’re able to seek fresh air and safety. People who are sleeping or intoxicated can die from CO poisoning even more easily.
Unborn babies, infants, and people with anaemia or a history of heart or respiratory disease are especially susceptible to the effects of CO exposure. Breathing low levels of the gas can cause increased chest pain and fatigue in people with chronic heart disease. Even healthy people who survive breathing high levels of CO can be left with permanent heart or brain damage.
If you think you’re experiencing carbon monoxide poisoning
Get fresh air immediately. Turn off any fuel-burning appliances, and go outside. Call emergency medical services if anyone shows signs of losing consciousness, or if other symptoms do not quickly improve. Even if you start to feel better, call your doctor at once and tell him or her that you suspect CO poisoning.
If you’ve been suffering from chronic ‘flu-like symptoms, ask your doctor if it could be low-level CO poisoning, and have any fuel-burning appliances professionally checked.
How to prevent carbon monoxide poisoning
Carbon monoxide poisoning can be avoided simply by making sure you know how to use fuel burning appliances correctly with sufficient ventilation, and getting them professionally inspected once a year.
The following guidelines from OCSA as regards portable generators can be applied to other fuel-burning appliances also:
- Never use a portable generator inside a home, garage, shed or other partially enclosed space, even if doors and windows are open.
- Use portable generators outside only, far away from the home. Keep the generator away from openings to the home, including doors, windows and vents.
- Read the label on the generator and the owner's manual, and follow the instructions.
- Install CO alarms with battery backup in the home outside each sleeping area.
Why carbon monoxide forms during incomplete combustion
When carbon-based fuel burns efficiently (i.e. there is plenty of oxygen), then each carbon (C) atom in the fuel bonds with two oxygen (O) atoms from the air to form carbon dioxide (CO2), the same gas we normally exhale. But when there isn’t enough oxygen available for the fuel to burn completely, then each carbon atom bonds with just one oxygen atom to form carbon monoxide (CO).
- Health24, updated October 2009