South Yorkshire Fire and Rescue has deployed four engines to tackle a blaze at a railway engineering company in Kirk Sandall.
Firefighters are still fighting the blaze at Trackwork Resources Ltd at Kirk Sandall Industrial Estate.
The SYFR Twitter account tweeted: "The fire in Kirk Sandall involves a filtration system in an industrial unit. There are no reports of any injuries."
A fire engine could be seen outside the company gates but staff were not allowing anyone access into the site and no flames or smoke could be seen from the road.
More to follow.