Three people were hospitalized after a fire at the Tata steel site in Scunthorpe.
The blaze started at about 2am, according to Humberside Fire Service.
The fire service said the situation was under control.
A Tata Steel spokesman said: “We had a fire in the power station at our Scunthorpe plant at 2:00am today (22 November) which led to three employees being hurt, all of whom have now been released from hospital.
“Our on-site emergency fire and rescue services arrived at the incident two minutes after the alarm was raised ensuring that the fire was dealt with quickly, restoring safety and ensuring that those affected were treated with the utmost speed, care and professionalism.
“As is established practice in these circumstances, a full investigation has been launched to establish the causes of today’s incident. Steel production was not affected by the fire.”
The BBC also reported that a fire at a plastics factory in Tamworth, Staffordshire on Thursday afternoon caused the cancellation of trains on the nearny by railway. No-one was hurt in the incident on Lichfield Road Industrial Estate.
Witnesses reported seeing large plumes of black smoke from up to 10 miles away.