The man in charge of the company which owns the power station where an explosion yesterday claimed the lives of three employees today pledged to make sure such an incident never happened again.

Jeff Skilling, chief executive officer of Enron Corp USA, today made a short statement about the blast at Teesside Power Station.

Mr Skilling, who flew from the United States to see the accident site for himself, said: "It is difficult to express Enron's and my personal shock and anguish over the accident yesterday.

"Enron employees worldwide share the grief of our employees here on Teesside.

"We pledge to work with the authorities to ensure it never happens again anywhere."

Enron's chief executive of its Teesside operation, Tim Underdown, said the three men who died would not be named by the company until they had been formally identified and all relatives informed.

He said today that the news that a third member of staff had died early this morning in hospital had been another devastating blow for the company.

He added: "We have now lost three dedicated and popular colleagues and no words can sum up the sorrow and hurt that we all feel.

"A fourth person remains in Middlesbrough General Hospital and is in a stable condition. We all hope and pray for his speedy recovery".

Mr Underdown said friends and family of the people involved were being helped by a company support team in partnership with trained counsellors and experienced emergency services personnel.

The power station remained offline today, he added, but there was no risk to the public at large.

Mr Underdown said: "I can that safety is paramount in all Enron operations and the company strives to prevent all incidents.

"All that said, any incident or injury is one too many and the tragic events of yesterday will leave a permanent mark on us all."

Mr Underdown said the company would issue up-to-date information about its safety record shortly.

Updated : 14:50, Thursday 9th Aug.