Firefighters have been ordered not to sit on a new batch of chairs - until they have been briefed on the dangers.
The chair is not sold with safety instructions
Crews at all 41 stations across Greater Manchester will be given the £400 reclining seats, which are also used for firefighters to sleep on.
But fire service bosses said staff could not sit or lie on the devices before reading a four-page manual.
A spokesman said the manual was issued at the request of a union health and safety representative.
Greater Manchester Fire and Rescue Service bought 325 of the chairs after chiefs decided to remove beds from dormitories across the region.
HOW TO USE A CHAIR
Place your personal issue head protector onto the chair prior to use
Sit fully back onto the chair seat and get ready to recline
To release the mechanism simply lift the lever under the right hand arm of the chair
To fully recline the chair hold onto the arm rests and push backwards
To upright the chair, the occupant should sit up slightly into the semi-reclined position, hold on to the armrest then press downwards with their heels until the action locks chair into flush position
They are not sold with safety advice and the four-page pamphlet was drawn up by the service.
The manual includes a warning that states: "Only personnel who have been instructed in the use of the Calcot reclining chair are allowed to use them."
The service said that staff would not be "trained" in how to use them - but admitted there was a ban in place until staff had read the instructions.
A spokesman said the manual was issued on the advice of an ergonomist and a request from a Fire Brigades Union (FBU) health and safety representative.
He said: "The chairs arrive in the station and firefighters are given a short guidance document in how to use them. They are just told to read the instructions.
"As an emergency service that attends incidents on a daily basis where people are trapped in all sorts of machinery and moving parts, it is only right and proper we make our own employees aware of any dangers."
The chairs have been installed in Rochdale, Bury, Oldham, Salford and Trafford and will be used throughout the service by the end of February.