Residents in Lurgan have been warned to be vigilant, after carbon monoxide was detected at a home where a well-known man was found dead on Sunday.
Glyn Girvan (72) was found at his home in Albert Street in the Co Armagh town.
The widower was described as a valued member of the community and was highly thought of by residents.
The Northern Ireland Fire and Rescue Service said it was alerted to the incident at 9.40pm on Sunday by the PSNI.
"Two fire appliances from Lurgan Fire Station and one fire appliance from Portadown Fire Station, attended the incident," a spokesperson for the service said.
"Wearing breathing apparatus, firefighters entered the mid-terrace property and using gas monitors confirmed the presence of carbon monoxide."
A 60m exclusion zone was put in place and residents in the area were advised to stay indoors. Firefighters then ventilated the property and the incident was dealt with by 11.17pm.
The pensioner, whose wife Shirley died 20 years ago, was an avid motorcycle racer, taking part in local events, the Lurgan Mail reported.
He was father to Glyn Junior, Paul, Keith and Bronwyn and had 10 grandchildren.
Lurgan councillor, Keith Haughian, who lives in a neighbouring street, said: "These are tragic circumstances for anyone to pass away.
"He was a valued member of the community. He was well-known and had been in the area for years and years."
The Sinn Fein councillor described the detection of carbon monoxide at the property as "very concerning".
"If anybody has any fears, or suspects that this might be an issue in their own home, then they should contact the relevant authorities and ask for it to be checked."
He also urged people to check on elderly members of their family or extended family.
He added: "I extend my sympathies from myself and the local community. It's a huge loss for everybody - especially for the family."
DUP Upper Bann MLA, Carla Lockhart, said: "My thoughts and prayers are very much with the deceased and his family. This is shocking news for a very close-knit community.
"Obviously it raises concerns again regarding carbon monoxide and the need to do more to raise awareness and to encourage people to install carbon monoxide monitors in their home."
PSNI Sergeant Nicholas Woods said: "Police are investigating the circumstances surrounding the sudden death of a man in the Albert Street area of Craigavon on Sunday, December 4.
"A post mortem is due to take place. There are no further details at this stage."
His funeral arrangements are to be release at a later stage.