Carbon Monoxide (CO): Risks, Symptoms and Prevention

What is carbon monoxide?

Carbon monoxide, also known as CO, is a highly toxic gas and can be fatal in high doses. Odourless and invisible, it is generated by the incomplete combustion of fossil fuels. The incomplete combustion of fuels such as wood, coal or gas produces this dangerous gas. CO spreads very quickly in the air. It enters the lungs and reduces the level of oxygen reaching the vital organs.

Be careful not to confuse it with CO2. Carbon dioxide (CO2) is a non-toxic gas. It plays a vital role in the respiration of living beings and in the life processes of plants.

Where does carbon monoxide come from?

In France, carbon monoxide poisoning affects nearly 3,000 people a year. This dangerous gas is potentially lethal, which is why it is important to identify the source of its emission. In winter, when the cold is more intense, the risks associated with carbon monoxide poisoning increase. CO can come from:

• Oil, coal, gas or wood heating equipment, often used to combat the cold;
• Individual gas boilers, which can emit carbon monoxide in a poorly ventilated cold environment;
• Petrol-powered tools and appliances such as lawnmowers or brush cutters, used for various tasks even in the cold;
• Outdoor equipment such as barbecues, oil lamps and camping stoves, sometimes used outdoors to keep warm in cold weather;
• Gas-powered household appliances such as ovens, cookers and space heaters, used more frequently to protect against the cold;
• Vehicles with combustion engines, particularly used for travelling in cold weather.

In winter, it is crucial to take extra precautions to avoid the risk of carbon monoxide poisoning in cold environments.

Here are some examples of situations where carbon monoxide can be emitted:

Unmaintained or defective appliances

• An unmaintained fireplace
• Gas boilers that are incorrectly adjusted
• A defective stove

Appliances or vehicles used in an enclosed space

• Starting a car in a garage
• Starting combustion tools in a shed

Inappropriate use of appliances

• Using a grill or barbecue indoors
• Leaving a space heater on for a long time

In winter, these appliances are used a lot in many places. That is why regular maintenance is strongly recommended to improve the safety of homes. It is important to have these appliances checked by qualified professionals in different places. Checking these devices will significantly reduce the risk of carbon monoxide poisoning in several living areas.

How does carbon monoxide affect health?

A little science

In its normal state, haemoglobin, which makes up red blood cells, is charged with oxygen. In the event of poisoning, the oxygen attached to the haemoglobin (which then becomes oxyhaemoglobin) is replaced by CO, which transforms the (oxy)haemoglobin into carboxyhaemoglobin. The lack of oxygen then causes a general dysfunction of the cells.

This asphyxiating gas spreads rapidly in the air and can be fatal within an hour!

In pregnant women, carbon monoxide can cross the placenta. CO makes the foetus unsafe and can put it in serious danger. It can cause serious neurological damage or even kill the foetus.

The effects of CO on humans

The effects of carbon monoxide vary according to:

• The amount of carbon monoxide in the air;
• The duration of the person's exposure;
• The person's sensitivity and state of health.

With low exposure, the victim may experience headaches, nausea or a little fatigue. This can lead to mild carbon monoxide poisoning. With medium exposure, the headache symptoms are persistent. Sensations of dizziness, lightheadedness and blurred vision appear. The person will feel drowsy and their heart rate will increase, which can lead to more severe poisoning. In the case of high exposure, the individual will feel very weak. They may faint or even go into convulsions. If no action is taken, the victim may fall into a coma or even die from severe carbon monoxide poisoning.

Treatment will depend on the level of poisoning. For mild cases, treatment with fresh air and oxygen may be sufficient. However, for more serious cases, intensive medical treatment will be necessary, including the administration of pressurised oxygen. Medical follow-up is essential to ensure that the treatment is effective and that the person does not suffer any after-effects.

What to do in case of poisoning?

Poisoning can affect several people in the same household. If you have a carbon monoxide detector, it will sound if CO is present. At the first signs of weakness due to poisoning, you must act quickly.

Take the right steps:

1 - Cut off the power supply to the CO emitting device

2 - Evacuate the premises

3 - Call the emergency services by dialling 18, 15 or 112 (114 for the hearing impaired)

Before resuming a safety check, do not enter your home without being invited to do so by the emergency services. A quick assessment of the situation is essential to ensure everyone's safety. It is strongly recommended that you call in a professional to carry out a full assessment and ensure that no other sources of danger remain. A professional will also be able to make sure that all appliances are in good working order and do not pose any risk to the health and safety of the occupants.

Prevent the risks of poisoning

Throughout the year, it is important to maintain the appliances in your home to avoid CO poisoning. To do this, certain rules must be followed:

• Ventilate the home for at least 10 minutes a day (even in winter) to improve indoor air quality;
• Minimise the prolonged use of auxiliary heating systems;
• Check and maintain household appliances regularly to ensure they are working properly.
• Keep CMV and other air inlets/outlets clear to ensure good air circulation.
• Follow the manufacturer's instructions for combustion appliances for correct maintenance.

Carbon monoxide is dangerous and toxic. To prevent this risk, it is strongly recommended that a home or room be equipped with a carbon monoxide detector (DAACO). This will emit an audible signal to warn occupants of the presence of CO in the room. Regular maintenance of the detector is also essential to ensure its effectiveness.