WILTSHIRE Fire and Rescue Service is reminding people to install and regularly test their carbon monoxide alarms.
Carbon monoxide is produced by the incomplete burning of carbon-based fuels, and most cases of poisoning are caused by gas appliances and flues that have not been properly installed or maintained, or are poorly ventilated.
Residents are being urged to look for signs on certain appliances which could lead to the production of carbon monoxide.
These include yellow or orange rather than blue flames, soot or yellow or brown staining around or on appliances, pilot lights that frequently blow out, and increased condensation inside windows.
People should also look for signs of carbon monoxide poisoning, which can be confused with food poisoning, flu or simple tiredness.
Symptoms include headaches or dizziness, breathlessness, nausea, loss of consciousness, tiredness, chest or stomach pains, erratic behaviour and visual problems.
Anyone with any of these symptoms who believes they may have been exposed to carbon monoxide should seek urgent advice from a GP or an A&E.
In an emergency, call 999.