A storage building at the Stornoway Trust's sawmill in Lews Castle Grounds was destroyed by fire in the early hours of this morning.
Three appliances attended the incident, two from Stornoway and one from Shawbost, at 5am.
There were around 22 fire and rescue personnel involved in the incident, which involved a fire in a storage building measuring 40m x 10m.
The building was well alight when crews arrived and firefighters in breathing apparatus used two main jets and a ground monitor to extinguish the fire.
Crews also used a Honda pump and were able to draw water from a nearby stream. There were also two LPG cylinders involved in the fire, which was brought under control by 8.30am.
The storage building was destroyed by fire as well as some plant machinery.
Local fire and rescue officers will carry out an investigation to establish the cause of the fire.
Station Manager Steve Oliver said: “The fire was very close to administrative offices and other workshops and crews worked very hard to preserve as much of the building as they could.
“The roof is in an unsafe state and will require to be made safe before investigations can commence.”