Paramedics with the air ambulance have been called out after a man injured himself with an angle grinder.
The ambulance was called out shortly after 1am to Peterlee after the man, who is believed to be in his 60s, suffered severe injuries.
He was treated at the scene then flown to James Cook University Hospital in Middlesbrough.
A spokesman for the Great North Air Ambulance Service (GNAAS) said: "GNAAS was called to assist NEAS paramedic on scene with a man who had injured his leg with a angle grinder.
"The man was treated on scene by the GNAAS team who treated his wound and admistered pain relief before transporting him to hospital."
The man is described as now being in a stable condition.