A KIDDERMINSTER firm has been fined £30,000 after a factory worker lost both his legs in an explosion.

Welder Clive Dainty was thrown across the factory floor when the lid of a large metal vessel he was pressure testing blew off at Filtration Services Engineering Ltd at Oldington Trading Estate, Kidderminster.

The 51-year-old suffered injuries to most of his body and later lost both his legs. He spent months in hospital and has limited movement in his arms, suffered injuries to his head and internal organs and is in a wheelchair for the rest of his life, Ben Mills, prosecuting, told Worcester Crown Court.

The firm was also ordered to pay £15,000 costs after pleading guilty to breaching regulations governing safety at work.

Mr Mills told the court the bucket-shaped filtration vessel had been delivered by another company shortly before the accident on December 8, 2011.

It was decided to check the welding by air pressure testing rather than the usual method of filling it with water and dye. The method had been used before but infrequently and Mr Dainty, from Kidderminster, was given no training or written instructions.

The company failed to carry out a risk assessment and did not clear the area, secure the vessel to the floor or put it in a security cage, Mr Mills said.

Instead, it was held on a table by two other workers, who suffered minor injuries in the accident, and the 710-millimetre diameter lid secured with 20 bolts. Mr Dainty then stood in front of the lid while the vessel was filled with air, similar to inflating a tyre, and he was tightening the bolts with a wrench when the lid blew off with "explosive force" and a noise described as sounding like a bomb going off. He was blown across the room into some shelving while the vessel flew backwards nine feet.

Mr Mills, acting on behalf of the Health and Safety Executive, said free guidance on pressure testing was easily available on the internet from the HSE.

Dominic Kay, for the company, said mistakes had been made but not as a result of cutting costs or corners. He said the combination of events had led to a "perfect storm" on the day of the accident and the company felt genuine remorse.

It had been a family firm since 1957 and employed 50 workers. The firm had voluntarily paid Mr Dainty £30,000 since the accident and he was also involved in a civil claim for compensation.

Although the firm had a healthy turnover, it did not make a huge profit, Mr Kay said.

Judge Robert Juckes QC said Mr Dainty must have been a very tough man to survive the explosion. He said the injuries had been "catastrophic." The company was well run and with a good safety record but it had made a number of mistakes and carried out the testing in a very crude way.