SAFETY experts have again warned Huddersfield householders about the dangers of carbon monoxide.
The warning came after Stacey Rodgers unveiled a garden in memory of her son Dominic, who died when fumes seeped into his bedroom while he slept.
A special garden in his honour was unveiled at his school - Christ Church Woodhouse Junior and Infant, Deighton - on Friday.
Chris Bielby, head of quality and standards at British Gas, said: "What happened to Dominic was very tragic and we wouldn't want to see this repeated anywhere else.
"We would urge everyone to be aware of the dangers and take simple steps to minimise the risks of carbon monoxide poisoning."
Carbon monoxide is a highly-poisonous gas which can be produced by burning any fossil fuel such as coal, wood or natural gas without sufficient ventilation.
It does not smell and cannot be seen.
It can escape into a home if a gas appliance is not properly maintained or installed or if an air vent, flue or chimney becomes blocked.
Warning signs are staining, sooting or discoloration on or around boilers, fires and water heaters.
Pilot lights and other gas flames that normally burn blue will change to yellow or orange.
Common symptoms of carbon monoxide poisoning are headaches, dizziness, sickness, confusion and extreme tiredness.
Gas Emergency Services can be contacted on 0800 111 999.