Two men have been released from hospital after suffering minor burns in an explosion at the UK’s largest steelworks.

Several fires broke out at the Tata Steel site in Port Talbot in the early hours of Friday morning after molten metal came into contact with cold water on a railway track.

Several bright flashes could be seen in video purported to be of the incident shared online.

One local resident tweeted: “There was just a big explosion from Port Talbot steelworks that just shook the house, hoping no one was hurt.”

Emergency services including paramedics and firefighters rushed to the complex after 999 calls began to stream in at around 3.35am.

Stephen Davies, a Unite union representative for the site, said the two injured men had been been on the train carrying molten metal and suffered “superficial” burns in the incident, one to the back of his head and the other to his chest.

Mr Davies said: “We’re working at the moment closely with management to find out exactly the issues that have take place in the early hours of this morning.

“This was totally out of the blue. Our safety record down there has been excellent. So it’s disappointing to hear what happened.”

Mr Davies said production on the railway line had been put on hold for the time being, while an independent company would be employed to determine whether there are any issues with the railway line.

Work at the site recommenced around 7am after emergency services had left the scene, and after an inspection from officials confirmed all fires had been put out and there were no concerns about the hazardous effect of smoke on workers.

Tata and the Health and Safety Executive both said they had launched investigations into the incident.

A spokesman for Tata said: “Two of our employees suffered minor injuries and received treatment. We continue to be in contact with them.

“We are investigating the cause of the incident and are working closely with relevant agencies including the Health and Safety Executive.

“Customer orders have been unaffected and we continue to supply steel to both customers and our downstream businesses by using existing  stocks.

“Meanwhile we are working towards bringing at least one of the two blast furnaces back online within 48 hours.”

A spokesman for the Health and Safety Executive spokesman said inspectors had already visited the site and their own investigation was under way.

Politicians called for lessons to be learned from the incident, and praised the steelworkers at the site for their work in “challenging and dangerous circumstances”.

Aberavon MP Stephen Kinnock said: “The men and women at our Port Talbot steelworks do an absolutely fantastic job, often in challenging and dangerous circumstances.

“With this in mind I’m pleased that Tata are conducting an investigation into the causes of last night’s incident. It is important we understand the causes of the blast, to reassure workers and local residents that the highest standards of safety are being upheld.”

Earlier, Mr Kinnock said the incident “raises real concerns about safety at the works”.

He wrote on Twitter: “It could have been a lot worse. Grateful as always to the emergency services for their rapid and effective response.

“@TataSteelEurope must conduct a full review, to improve safety.”

Business Secretary Greg Clark thanked emergency services who responded to the blast, adding: “I will want to see the outcome of Tata’s investigation to ensure that any lessons can be learned from today’s incident to ensure the ongoing safety of the Port Talbot workforce and community.”

Wales Secretary Alun Cairns said: “It is important that Tata Steel Europe addresses safety concerns that could arise as a result of this incident to ensure the wellbeing of staff and residents in the local and wider community.”

In the early hours of the morning, South Wales Police said the fire had caused some damage to buildings, but announced there was no need for concerns about the after-effects of the incident on locals.