CARBON monoxide killed a father and two children after a crisp wrapper got lodged in a chimney, an inquest heard.
The "silent killer" claimed the lives of Trevor Wallwork (52), his daughter Kimberley (12) and nine-year-old son Harry as they sat in the sitting room of their home.
They had been watching television together and the Christmas lights were twinkling in the corner of the room at the scene of the tragedy in December 2011, a coroner's court was told.
The scene was described by Sligo Coroner Dr Des Moran as one of the saddest he had ever come across.
When firefighters and gardai arrived at the scene they found Mr Wallwork sitting in an armchair facing the television with a blanket over his knees and his head slumped to one side. His two children were lying on the floor. Kimberley was in her pyjamas while Harry was dressed in jeans and T-shirt and had his head on a cushion.
All three were pronounced dead at the scene, in a house about a mile from the village of Gurteen, Co Sligo, on December 18, 2011.
The jury was told that a plastic bag from a crisp multi-pack was thrown on to a coal fire which was not hot enough to melt it, but filled it with gas "like a hot air balloon".
It blew up and became stuck in the chimney, releasing carbon monoxide back into the room.
The jury at Sligo Coroner's Court called on householders to install carbon monoxide monitors and to think twice about what they throw on the fire.
Dr Moran was told that Mr Wallwork's wife Susan, who was in Sligo General Hospital being treated for cancer at the time of the tragedy, had died six months later.
Her daughter, Vicky Barnes, who raised the alarm after discovering the bodies, said she hoped that lessons would be learned from the tragedy.
Speaking after the inquest, she said the evidence "brought it all back".
She supported calls for carbon monoxide alarms and said people should think about what they throw on to fires.
Sligo's Chief Fire Officer Paul Coyle, who attended the scene, said that death would have occurred within minutes given the high levels of carbon monoxide released in such circumstances.
Mr Wallwork was originally from Salford in Manchester and his family moved to Ireland six years earlier. His children attended the local Mullaghroe primary school.
Mr Coyle said he had ruled out both the oil-fired central heating system – which did not have enough fuel to operate – and a gas fire in the hall as the source of the gas.
Mr Coyle told the jury that after climbing up on the roof he concluded that the chimney was obstructed, and using a tongs he removed the crisp bag which was 1.2 metres from the top.
Mr Coyle pointed out that the toxic carbon monoxide gases which were released could not be seen or smelled. He said carbon monoxide detectors should be in all homes using any kind of combustible fuel to prevent such a tragedy recurring.
Deputy State Pathologist Dr Michael Curtis, who carried out the post-mortem examinations, found that the cause of death in all three cases was carbon monoxide poisoning. He told the jury that there was no sign of trauma or physical injury on the bodies.
Echoing the calls for carbon monoxide alarms to be installed, Dr Moran pointed out that houses today tended to be better sealed which reduced ventilation making monitors even more crucial.
The jury found the cause of deaths in accordance with the evidence that they were accidental and caused by carbon monoxide.
Hundreds of local people attended a memorial service for the family in Sligo before they were brought back to England for burial.