Crews from Worksop, Retford and Maltby were called at around 4.30am to the plant in Shireoaks Road.
Recycling material had caught fire and more than 40 firefighters attended. Two fire engines are still at the scene.
People living nearby are advised to keep doors and windows closed in case of any remaining smoke.
Shireoaks Road is still closed between the A60 Sandy Lane junction and the Tylden Road junction.