Five fire engines and an aerial appliance are currently at the scene of the fire in Todwick Road, Dinnington.
A spokesman for South Yorkshire Fire and Rescue said they received a call about the blaze, which is believed to be around 40 metres by 50 metres in size, at 5.20pm.
South Yorkshire Police are believed to have closed a section of Todwick Road while work to extinguish the fire continues.
An eye witness said: "I noticed the fire while I was in my garden. You can see smoke from it for miles across Rotherham and south Sheffield."