Experts are assessing the damage caused by a fire at Shorts aircraft factory in Northern Ireland.
A total of 85 firefighters and 20 appliances brought the early morning blaze under control as roads were temporarily closed near the site in east Belfast.
Chemical specialists from the firm's parent company, Bombardier Aerospace, were called in after fire chiefs became concerned at how the blaze might affect materials in the premises.
There is no confirmation yet of what caused the fire and no reports of injuries.
A spokesman for Bombardier Aerospace said: "There was a fire this morning in a section of our Airport Road factory where metal components are cleaned before going to assembly lines.
"No one was injured. No one was working in the area at the time. The fire was discovered by maintenance staff who had arrived to do calibration work.
"The emergency services were on site promptly. The building was evacuated."
The spokesman added: "The fire which was then extinguished was in an area where new treatments equipment was installed but was not yet operational. A full inspection of the area and the cause of the incident will be undertaken shortly when the area has been declared safe."
The Northern Ireland Fire and Rescue Service (NIFRS) said the alarm was raised at 8.22am and that crews arriving at the scene were faced by a rapidly developing fire.
"This incident was complicated by the presence of a number of chemicals which only become a major concern when they are involved in fire," said a fire service spokesman.