The fire occurred at a power station at the company's plant in Scunthorpe in the Yorkshire region of England.
The three injured persons were taken to Scunthorpe General Hospital with "radiated" burns but were released after treatment.
Tata said the cause of the blaze, which was tackled by an on-site crew and local firefighters, was being investigated.
"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," a company spokesperson said.
Martin Foster, the Scunthorpe works convenor for the 1,200 members of the Unite trade union members on the site, told the local media that the union will have representatives involved in the investigation process.
"It's early days at the moment, so we are waiting to find out more detail on what happened, why and what impact, if any, this will have on the business," he said.
