Up to nine fire crews are tackling a large blaze near a Suffolk airfield.
The fire is believed to have started when equipment overheated during a manufacturing process at a fibreglass moulding plant near Parham airfield.
At its peak, up to 13 crews were onsite dealing with the blaze.
All workers have been accounted for, and there are no casualties.
Those nearby have been asked to keep windows and doors closed, due to the large volume of smoke in the area.
A Suffolk Fire and Rescue Service spokesperson said: “We understand from workers that the cause of the fire may have been due to some overheating during their manufacturing process.
“However, we will be carrying out a fire investigation when it safe to do so, to identify the cause.”
The fire service confirmed it has now surrounded the fire and is making “good progress” with extinguishing it.