Russell Meredith, 36, operations director at Ravensbourn factory and his father David Meredith, 74, who is a co-owner of the firm, said the fire started after midnight when three people were still in the factory.
In the horrifying footage, the "firenado" is seen swirling as firefighters rushed to the scene.
The blaze was so bad, Augusztinyi said, that it took firefighters a day and a half to extinguish the flames: The first call reporting the fire came in shortly after 1 a.m. Tuesday, but the last fire activity ceased at 1 p.m. Wednesday, he said. The column of fire forms when eddies caused by the blaze lead to a powerful rotating updraft.More news: Canada shooting: Several dead in Fredericton, New Brunswick
It was reported that firefighters had the fire under control about 3:00pm.
As the Leicestershire Fire and Rescue Service Ashby Station explained on Facebook, the fire whirl, or firenado, is created when "cool air enters the top of the hot air", which causes "a swirl similar to how a tornado is formed".
"Whilst we were firefighting at Occupation Lane we witnessed a firenado or a fire whirl".More news: Phil Thompson predicts where Liverpool FC, Man City will finish
The fire had also spread to a small site building and a number of fork lift trucks at the property, Derbyshire Fire and Rescue Service said.
Thick black smoke from thousands of plastic pallets on fire could be seen across the East Midlands.
As a result of the fire, residents were advised to keep their windows and doors closed as a large plume of black smoke blanketed the sky, able to be seen as far away as Nottingham.More news: Yerry Mina completes Everton move