An equipment cleaner at a power station had to be cut free from narrow duct when he collapsed while he was working.
The 45-year-old cleaner was inside a gas vent at the Fibrowatt power station near Thetford, Norfolk, when he had a back spasm and found he could not move.
Staff at the plant, which is fired by waste poultry litter, helped cut him free on Thursday night.
Engineers cut a hole in the side of the vent so he could be pulled through when emergency service crews arrived.
Ian Edgar, asset director for EPR, which runs the plant, said: "To make it a horizontal rather than a vertical recovery we cut a large hole in the ducting, and this allowed emergency service crews to rescue him speedily.
"As part of our confined space procedures we have staff outside the working area and also a team inside the area.
"That system worked well for Thursday night's operation."