THE only surviving eyewitness of a massive explosion which ripped through a Teesside power plant has spoken for the first time of the moment he witnessed the deaths of his three workmates.

Graeme White of Billingham, still bandaged from his injuries sustained in August 2001, told the inquest how his whole body was in flames after the explosion at the plant at Wilton, near Redcar.

The inquest at Teesside magistrates court heard that Mr White was one of four men involved in maintenance work on a transformer at the plant formerly owned by American company Enron.

Mr White, 37, and colleague Andy Sherwood, 36, of Hartlepool, were there to observe an unusual attempt to manually 'tap' the electrical transformer to adjust the voltage in order to close a circuit breaker.

Mr Sherwood and Darren Higgins, 28, of Normanby, caught the full blast and died at the scene. The pair's injuries were so severe they could only be identified by their dental records.

Another man, Lawrence Paul Surtees, 40, known to everyone as Paul, died the following day after sustaining 90 per cent burns.

Mr White is still undergoing surgery for his burns to his body. His right hand was bandaged when he gave evidence on Wednesday.

He told the inquest he was there only to observe the unusual procedure. The operations technician said: "I was minutes, no more than two minutes, behind the others. When I got there Paul and Darren were on the transformer platform and Andy was just by the ladder.

"Paul and Darren were actually pulling the lever when a buzzing started and there was a flash and bang. I saw a flame and I saw my whole body was in flames. I would say I was conscious through all of it.

"The first thing I could see I was underneath three or more cooler water reserves. I saw a big puddle of water and jumped in it. I got up and threw my jacket off and jumped into the safety shower."

Earlier, operations manager Alan Robinson told the inquest that, in his opinion, a written risk assessment programme should have been completed before work took place

On the previous day at the hearing Ian Clifford, site director at the power plant, said the transformer should not have been tapped while it was switched on, and the attempt to do so followed a meeting of senior staff.

Mr Higgins and Mr Surtees had extensive training and experience with the system. They would have been fully aware of the consequences.

"We know exactly what happened, but we don't know why," said Mr Clifford. "The whole issue of why it was tapped is a mystery."

Speaking at the inquest on Thursday morning, health, safety and environmental engineer Louise Russell told coroner Michael Sheffield that procedural rules had been changed since the accident.

She explained that an inappropriate padlock had been fitted on the transformer and was removed by the technicians.

There was no procedure in place to deal with such a situation at the time but now a 'sacred system' had been installed.

She said: "If there is a lock that needs to be removed it now must be taken up to the shift manager and an operational manager to be passed. They must make a judgement about what to do."