A manufacturer of high-pressure gas cylinders has been ordered to pay more than £800,000 in fines and costs after a worker was fatally wounded by shrapnel ejected from testing equipment.

On 10 June 2015, John Townsend, 64, was leak testing eight 1,500-litre cylinders, by applying compressed air inside to create pressure, at the company’s Sheffield site. While in the process of venting the air through the test manifold, it catastrophically failed and killed him.

Health and Safety Executive (HSE) investigators found that prior to installing the fittings, 1.5 litres of a mineral oil-based corrosion inhibitor had been placed into each of the cylinders. The incident occurred because the inhibitor contaminated the leak test manifold during venting of cylinders and was subjected to enough pressure inside the manifold to ignite and cause the test equipment to fail.

At Sheffield Crown Court, Chesterfield Special Cylinders was found guilty of breaching s 2(1) of the Health and Safety at Work Act. The company was fined £700,000 with full costs of £169,498. The penalty must be paid in instalments by January 2023.

After the hearing, HSE inspector Eddy Tarn said: “This was a tragic and wholly avoidable incident, caused by the failure of the company to identify any additional risks that arise when work processes are adapted.

“Companies should accurately identify and control all potential hazards in the workplace and thereafter monitor performance through effective supervision.”

According to local newspaper reports, Pressure Technologies chief executive Chris Walters said after the hearing: Chesterfield Special Cylinders and Pressure Technologies Group respect the decision of the jury and the sentencing that has been determined today. We deeply regret the events that resulted in the death of our colleague and long standing employee John Townsend, which has left a terrible gap in the lives of his family, friends and colleagues, with whom our deepest sympathies remain.

“The Pressure Technologies Group operates in safety critical industries. We are committed to achieving the highest safety standards and the judge has today remarked upon the company’s decent safety record and attitude,” he added. “This tragic incident occurred in June 2015 and in the period since then we have made significant changes and improvements to the way we operate at the Chesterfield Special Cylinders site and across all group sites as we continually strive to improve the safety of our operations and our employees.”