Two brothers and one of their wives who died in an empty water tank on a Southern NSW property have been identified.
Two brothers and one of their wives died in an empty water tank on a NSW property in a"tragic accident" after being overcome by fumes.
Andrew Basnett, 69, his wife Anne, 63, and brother 68-year-old Richard, have been remembered by friends as "upstanding" locals who "added a lot to the community".
The three family members bodies were found in a ground cement water tank on their property near Gunning, on the state’s Southern Tablelands on Thursday evening, after being overcome by fumes.
It's understood Andrew collapsed while cleaning the inside of the empty in-ground cement water tank on property just out of Gunning on Thursday.
Anne and Richard went into the tank to help him, but also collapsed.
"Everyone is very affected by it because it's just one of those tragedies that touches everybody," friend Craig Southwell told SBS.
Andrew was using a petrol pump to clean the tank, which may have been the cause of the build-up of fumes at the bottom of the water tank, police believe.
"It appears that it was lowered into the tank and that's caused the gases to be at the bottom of the tank," said NSW Police Superintendent Koutsoufis, from the Hume LAC.
It's believed the trio may have succumbed to carbon monoxide poisoning, he said.
A neighbour contacted emergency services just after 6pm on Thursday but all three were found dead.
"It appears that it was lowered into the tank and that's caused the gases to be at the bottom of the tank," Superintendent Koutsoufis said on Friday.
"It's an absolute tragic set of circumstances. A tragic accident," he said.
"It's devastated a family... it's also a devastating outcome for a small town like Gunning. So a lot of people are hurting at the moment."
The town of Gunning, with only a population of about 450, is mourning the loss of the three locals.
Rescue specialists were waiting for the gases to die down before retrieving the bodies, Superintendent Koutsoufis said.
The farm is at Oolong, about 10 kilometres from Gunning, which is on the Hume Highway.
Police said autopsies would be carried out in coming days.