The fire broke out just after 11am last Monday at the Vesper Drive factory.

Hallam fire officer Greg Chapman said the job was made more difficult because of an exploding gas cylinder.

"When we arrived, the front of the factory was alight and was venting, making a really high-pitched scream. That is about the time they [gas cylinders] go bang.

"When the cylinder exploded, it came out of the front of the factory, narrowly missing firefighters and smashing into the front door of the adjacent factory some 15 metres away."

Mr Chapman said it took firefighters about 45 minutes to put out the blaze.

"Aggressive firefighting prevented it from spreading. The guys did a wonderful job."

Mr Chapman said it was believed the fire started in a spray booth, but investigations were continuing.

Witness Steve Morton was picking up his mail at the nearby postbox when he saw the black smoke coming from the building.

"The noise of it was frightening, there was a really load piercing sound and then the gas bottle exploded.

"If I had of known it was a gas bottle, I would not have been standing around."

Mr Morton said it wasn't long until neighbouring factories started evacuating.

"You could see them bringing out filing cabinets and everything," Mr Morton said.

Mr Chapman warned business owners to be cautious over the Christmas period.

He said the best way to prevent fires was to turn off all electrical appliances at the wall.

"If you don't, there is still going to be the flow of electricity so it is still possible that something could fail."