Carbon Monoxide Information

Carbon monoxide is the 'Silent Killer' you can't see, smell or taste. CO can kill you before you are even aware it is in your home. Get an early warning with a carbon monoxide alarm.

What is carbon monoxide?

Carbon monoxide (CO) is a colourless, odourless, toxic gas created as a by-product of combustion and from sources such as (but not limited to) engine exhausts, fuel burning appliances, fireplaces and furnaces. Additionally, there are various situations that may result in CO being present in the home, such as cracked, disconnected, rusted or corroded flue pipes or improper appliance installation.

What is carbon monoxide poisoning?

Carbon monoxide is often referred to as the 'Silent Killer'. You can't see, taste or smell it, and it can cause sudden illness and death by robbing your blood of oxygen. It can harm you before you even know it's there.

Is your household at risk?

Carbon monoxide kills around 50 people a year in the UK and is the main cause of accidental poisoning in the home with over 600 people being admitted to hospital as a result of carbon monoxide poisoning each year. Experts suggest this figure could be a considerable underestimate. Anyone living in a home with fuel-burning appliances, a fireplace or an attached garage could be at risk of CO poisoning. Barbecues or gas-powered generators can also pose a risk of carbon monoxide poisoning if used close to the home. Carbon monoxide poisoning can affect anyone. However, certain groups are more susceptible, including unborn babies, infants, people with chronic heart disease, anaemia, or respiratory problems.

Symptoms of carbon monoxide poisoning

One of the reasons why accurate statistics on the true scale of carbon monoxide poisoning are hard to come by is because of the deceptive symptoms.

Symptoms depend upon the concentration of carbon monoxide:

  • At low levels of exposure symptoms include: headaches and nausea
  • At medium levels of exposure symptoms include: drowsiness and vomiting
  • At high levels of exposure symptoms include: collapse, coma and permanent brain damage which may lead to death

How do I make my household safe from CO?

  • Make sure that your appliances are installed by a competent Gas Safe Registered installer.
  • Make sure that all fossil fuel burning appliances are serviced by a registered engineer every year.
  • Install at least one carbon monoxide detector; ideally one near the likely source of carbon monoxide and one near your bedroom. CO alarms sound a loud alarm before carbon monoxide levels becoming threatening for average, healthy adults.

Which type of CO alarm?

CO detectors are available in a variety of models; including battery-powered units that work during power outages and don't take up outlet space; and combined smoke and carbon monoxide detectors that eliminate the need for two separate units and protect against two deadly household threats.

First Alert offers you a comprehensive range of CO alarms that comprise both standalone and combined units (see our products page for more info).

Where should I place my CO alarm?

Near sleeping or living areas. Additional units should be sited in each separate bedroom and on each level of your home within living areas.

How do carbon monoxide detectors work?

The sensing technology in a CO detector is different from that used in a smoke alarm. The CO detector measures the amount of carbon monoxide and the time of exposure.

CO detectors are designed to sound their alarm before an average, healthy adult begins to suffer symptoms of poisoning.

What if the detector goes off?

When the alarm detects a certain level of carbon monoxide over time, it will sound an alarm. It is very possible you may not be experiencing symptoms of CO poisoning when the alarm goes off; this doesn't mean CO isn't present in the air.

Do not ignore the alarm if it goes off.

In the event of an alarm, if any member of the household is feeling sick, immediately ventilate the home by opening doors and windows. Then leave the building and call the fire brigade. Gather everyone in one area and do a head count.

Do not re-enter the building until the fire brigade have done their check and given you the OK to do so. Have a qualified technician correct the problem should there be any issues.

If the alarm sounds and no one is feeling ill, open doors and windows and turn off all sources of combustion. After one hour close windows and doors, and resume fuel-burning appliances. If the CO alarm sounds again within minutes, call the fire brigade.

If you want more information on carbon monoxide awareness and safety precautions, contact your local fire brigade.


Reviewed: 02/05/2019 (doc:148 V1.1). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.