Warning over rise in carbon monoxide fatalities
Devon has been named as the top "hot spot" for incidents of carbon monoxide (CO) poisoning.
According to a report by the Gas Safety Trust, the number of fatalities has more than trebled in the UK.
Twenty-five people died as a result of CO poisoning in a 12-month period to 30 June, compared with seven deaths the previous year.
However the number of people affected by CO fell from 145 to 80, the Carbon Monoxide Hotspot Report 2011 said.
Inhaling CO, which is colourless and odourless, reduces the blood's ability to carry oxygen.
Faulty central heating systems, gas appliances and fires, blocked flues and chimneys can result in CO poisoning.
Statistically, Wales experienced the most poisoning incidents but taking the population into account, Devon was the top hot spot with five incidents which resulted in two fatalities.
Seven people died in Northern Ireland, while Essex was the only one of the six top hot spots to escape a fatality.
More than half (58%) of the incidents occurred between November and February, however there were also cases in the summer involving camping equipment and fires.
In August, two adults and three children were rescued from their tent at a camping park near Newquay, after being overcome by carbon monoxide fumes from a barbecue.
The Gas Safety Trust report contains figures of incidents gained from media reports, but it has warned that the real figures could actually be higher.
Spokesman Nigel Dumbrell said: "While deaths and serious injuries from CO exposure are relatively straightforward to record, the data does not reveal the extent of what might be termed 'near misses'.
"The records do not capture information about the number of people who are unwittingly exposed to low levels of CO poisoning - levels that may cause long-term ill health but go undetected."
Joyce Bridgewater, from Camelford in Cornwall, suffered low-level CO poisoning by breathing the colourless odourless gas in her home over a period of 10 years and now has to use a wheelchair.
The trust said further awareness activity was needed to increase the proportion of households with a CO alarm.
Of all the CO incidents recorded, none involving an alarm resulted in a fatality or serious injury.