An inquest jury has ruled a boy died of carbon monoxide poisoning after fumes from a faulty boiler in a neighbour's property seeped into his bedroom.
Dominic Rodgers was found dead in his bedroom in Spaines Road, Fartown, Huddersfield, in February.
The gas that led to his death is thought to have seeped through the floor of his room as he slept.
In a narrative verdict the jury said the deadly gas had come from a flue in an alleyway beneath his bedroom.
At the end of the three-day hearing at Bradford Coroner's Court the jury's verdict read: "Carbon Monoxide had percolated into his bedroom, emanating from a balanced flue serving the adjoining property, situated in the ginnel beneath.
"The balanced flue was to exhaust a central heating boiler.
"Subsequent examination revealed that the heat exchanger was covered with deposits and the regulator had failed."