A steelworker died and 13 others were injured, some seriously, after an explosion at a Corus steel plant last night.

The company said a "serious escape" of molten iron occurred at a blast furnace on the company's Port Talbot site in South Wales. It added the explosion happened at number five blast furnace.

About 3,000 employees work at the steel works, which produces three million tonnes of steel a year for the motor and other industries.

A Corus spokesman said: "We have deployed the full resources of our emergency planning procedures and the furnace area is now stable."

Local hospitals were also put on full scale alert.

Malcolm Ebdon, spokes-man for Morriston Hospital in Swansea, which has a specialised burns unit, said that some of the casualties were seriously injured.

Andrew Tutton, a crane driver on the site, arrived early for the night shift and was one of the few people allowed in before the area was sealed off.

He said: "I saw the black smoke and didn't really think anything of it because you see a lot of that around here.

"I arrived for work early and got here to be told that the number five blast furnace had blown out.

"They have not told us a lot about what is going on but they are treating it as a major incident. A lot of the boys who work here are in a terrible state."

Traffic on the nearby M4 came to a standstill as ambulances carrying the injured made their way to hospital.

Local councillor Clive Owen said furnace five had been due to be relined in 2004 and contractors had been working on it as an interim measure.

"They were going to be relining it in a couple of years and I think they were patching it up," he said.

"I heard about three explosions. I ran out to the garden to see what it was and I could see a lot of smoke. Then the fire engines and ambulances started coming in."

Michael Leahy, general secretary of the Iron and Steel Trades Confederation, was last night flying back from a union conference in Australia. because of the tragedy