The Northern Ireland Fire Service has paid tribute to John Winton, who was also a retained firefighter in Limavady.
A binman has died after being hit by the lorry he was working on.
The PSNI confirmed that John Winton, a cleansing operative, died after a road traffic collision at Mount Eden in Limavady at around 7.30am on Tuesday.
Mr Winton was also a retained firefighter at Limavady Fire Station.
PSNI Inspector Siobhan Watt said: “An investigation is underway to establish the full circumstances of the incident and police have appealed to any witnesses to contact them at the Collision Investigation Unit on 101, quoting reference number 195 of 06/11/18.”
The Northern Ireland Ambulance Service received a 999 called at 7.34am on Tuesday, November 6, following reports of a road traffic collision involving a pedestrian in Mount Eden.
Two emergency ambulances were sent to the incident. No one was transported from the scene.
In a statement, chief fire and rescue officer Gary Thompson gave his condolences to Mr Winton's family.
He said: “Northern Ireland Fire & Rescue Service (NIFRS) is devastated to learn of the death of our colleague Firefighter John Winton who died this morning in an off-duty incident.
“On behalf of NIFRS, I extend our sincere sympathies and condolences to John’s family, his mother Margaret and his children Lisa and Gavin, at this difficult time.
“John was a Retained Firefighter at Limavady Fire Station, having joined NIFRS almost two years ago on 19 November 2016.
"His untimely death at the age of 51 will be greatly felt by all who knew and worked with him. John was a dedicated Firefighter serving his home town with distinction and he was extremely popular amongst his colleagues. His death will be felt across the entire Service and the NIFRS family.
“John’s colleagues from Limavady Fire Station and neighbouring Stations of Dungiven and Crescent Link attended the incident this morning which happened on Mount Eden, Limavady at 7.36am.
“NIFRS is offering support to John’s family and his colleagues at this difficult time.”
SDLP councillor John Deighan said: "Condolences to the family of this man. It is such a tragic accident to happen to someone doing their daily working round. No one thinks when they are going out to work in the morning that they won't be coming back."
The Health and Safety Executive are aware of the incident and have attended the scene to make enquiries.