Humberside Fire and Rescue Service (HRFS) attended an incident at Tata Steel in Scunthorpe in the early hours of this morning.
The call was received at 01.57am and eight fire engines attended to assist site fire crews who were already on the scene.
Dry powder was used to extinguish the fire in a gas turbine.
Three employees suffered burn injuries and were taken to hospital.
All three were later released after treatment.
HFRS left the scene at 05.02am.
Tata Steel has launched a full investigation into the incident.