A carbon monoxide alarm alerted occupants of a property at Morwenstow, near Bude early this morning.
The occupants reported that they were feeling ill.
Six firefighters from Bude went to the property with a gas monitor which showed a positive reading for carbon monoxide in the building; the source of the carbon monoxide was isolated.
Once the suspected source of the carbon monoxide was removed the premise was ventilated by the fire service.
Three casualties were treated on scene by paramedics and appropriate advice to the premise occupants was given.
The Cornwall Fire & Rescue Service warn that carbon monoxide is “potentially fatal and even low-levels of the poison can cause lasting damage to your health”.
Statistics from CO Gas Safety found that on average, carbon monoxide poisoning kills 40 people per year and injures around 300.
From September 1995 to August 2010, 3,973 people in the UK had a near miss from accidental carbon monoxide poisoning - of which 2,085 required hospital treatment (of those 365 had lost consciousness).
For advice on what you can do to ensure you are not affected by carbon monoxide poisoning, log on to: http://www.cornwall.gov.uk/default.aspx?page=7287