Two firefighters were taken to hospital- one of them with 'life-changing injuries' after being hurt in a training exercise near Buxton.
The firefighters, based at Stafford Fire Station, were carrying out rope rescue training at Harpur Hill on Sunday, September 29.
Both firefighters were taken to Royal Stoke University Hospital where one individual continues to receive treatment for his injuries, are believed to be 'life-changing'.
The other firefighter was discharged from hospital with minor injuries.
Chief Fire Officer, Becci Bryant, said: “Everyone across Staffordshire Fire and Rescue Service is shocked and saddened by this incident and our thoughts remain with our injured colleagues and their families and friends at this difficult time and we would ask that their privacy is respected.
"We are working to support them and other colleagues who have been affected by this.”
The HSE has been informed and Derbyshire Fire & Rescue Service will undertake an independent investigation into the circumstances around this incident.