Neil Ferguson, of machinery manufacturers Shotblast Supplies, told how he arrived at the scene of the fire on Kilton Terrace to find a neighbouring unit ‘well alight’.
Pictures from the scene showed smoke and flames billowing from the large structure belonging to Abbey Glen Ltd - a business dating back to the 1800s which supplies workwear for industry.
Other photos taken the following day after the flames were doused show the building’s mangled interior through its caved-in roof.
Neil told how he rushed to the scene at about 8.20pm and started removing gas bottles from his factory to avoid an explosion if his building caught fire.
He said: “The fire service were hosing down the gable ends to stop the fire coming in.
“If they hadn’t done that we would have caught alight as well.”
During the blaze incident commander Matt Reavill tweeted how 10 pumps attended and three businesses had been disrupted.
He wrote (SIC): “Aggressive tactics stopped significant fire spread. Good work crews”.
It is understood no-one was injured.
It is not yet known how many people work at Abbey Glen or whether jobs will be at risk due to the fire.
A spokesman said: “As you can imagine it’s a stressful time at the moment and unfortunately the directors are not in a position to pass comment on the situation at the current time.”