WORKERS could have been killed when an explosion from two test tubes ripped through a laboratory, a court heard yesterday.

The explosion, at steel tube makers Paralloy, in Billingham, Teesside, turned two metal test tubes into "high velocity missiles", which wrecked a laboratory near to where staff were working.

The company, which employs 200 at Cowpen Lane Industrial Estate, was fined £12,000 at Teesside Magistrates' Court after pleading guilty to a charge of failing to ensure the health and safety of its staff.

It was also ordered to pay £4,980 costs to the Health and Safety Executive (HSE), which investigated the accident.

Dr David Shallow, for the HSE, told the court that if any staff had been in the laboratory where the tubes exploded on February 26, last year, they could have been killed.

The accident occurred during high-temperature tests of tubes made for use in chemical reactors.

An HSE investigation showed that water had got into graphite inside the tubes and had turned to steam, increasing the pressure in the test tubes. They were placed in furnaces to be heated to 1050C, but blew apart at 600C.

"The tubes in effect became high velocity missiles," said Dr Shallow. "The company was extremely fortunate that no one was seriously injured or killed. There's no feasible way that the tubes could withstand that pressure at the higher temperature."

A Paralloy spokesman said after the verdict: "The company has now altered its procedure for performance of this test."