Three members of the fire service have been arrested in connection with a Warwickshire warehouse blaze which killed four firefighters.
Ian Reid, 44, Darren Yates-Badley, 24, Ashley Stephens, 20, and John Averis, 27, died tackling the fire at a vegetable packing plant at Atherstone-on-Stour in 2007.
A spokeswoman for Warwickshire Police said: "This morning a 43-year-old man from Nuneaton, a 49-year-old man from Leamington and a 48-year-old man from the Warwick area presented themselves at a Warwickshire police station, where they will be questioned on suspicion of gross negligence manslaughter and offences under the Health and Safety at Work Act."
Last month the Fire Brigades Union said detectives were planning to arrest three managers who were involved in the incident command process.
FBU general secretary Matt Wrack said: "We are concerned at the move to arrest these individuals at this stage when all other key players have not even been interviewed.
"Evidence from our own investigation suggests there may be systemic failings."
The building was severely damaged by the suspected arson attack on November 2 and the fire is being investigated by police and the Health and Safety Executive.