West Yorkshire Fire and Rescue Service were called at 10.38am on December 21 to reports of a fire in an industrial site in the Upper Wortley area.
Crews from Hunslet, Moortown, Stanningley and Morley attended the blaze on the Barras site - close to the Wortley Liberal Club and Golden Fleece pub - with an aerial appliance from Bradford also used.
The police and ambulance service were also in attendance at the scene assisting crews.
Speaking to a YEP reporter, workers from a building nearby said they smelt plastic.
One said the building “just went up and there was so much smoke.”
Crews were seen using hoses and an aerial appliance to tackle the fire.
Many workers from nearby units were stood on the streets after being evacuated by the fire service.
Homeowners also watched on from their gardens on Barras Place and neighbouring streets.
It has not yet been confirmed which unit was involved in the fire.
An eyewitness, who works nearby, told the YEP: “We were told to leave one of the one units.
“The smoke is right across the sky, I can’t believe it.
“The fire service were very quick.”
There were no reports of any injuries, the fire service said.
The roads surrounding the industrial unit were closed by police whilst the fire was dealt with.