A failure to check for a gas leak by applying a “simple” and “fundamental” test on the pipework leading to Haut du Mont was the “’major cause” of the blast that killed ten people, an explosion investigator has told jurors.
Neil Armstrong (58), John Wright (60) and Lee Ward (59) are charged with unlawfully killing the victims of the Haut du Mont disaster on 10 December 2022.
The three men, who worked together in the network operations team at Island Energy, deny ten counts of gross negligence manslaughter – one for each of those who died in the blast.
Crown Advocate Simon Thomas, prosecuting, previously told jurors that the explosion occurred because the defendants failed to carry out a “crucial, basic and fundamental” test on pipework leading to Haut du Mont after reconnecting the gas supply on 9 December.
It is further alleged that Mr Armstrong then left an Emergency Control Valve at Haut du Mont “open and unplugged”, which allowed the gas to escape.
At the Royal Court yesterday, jurors heard evidence from Richard Siddons, who investigated the explosion as part of the UK Health and Safety Executive.
The expert witness, who has investigated more than 1,000 incidents across the world, is a member of both the Institution of Chemical Engineers and a Member of the Energy Institute.
Mr Siddons was asked about a message sent by the company’s managing director Clive Doyle to Mr Armstrong on 9 December
It read: “Neil, James – when doing leakage test I suggest keeping it circa 70 -75mb (max network operating pressure) then FIM the connected mains and services”.
Jurors heard the investigator confirm that a pressure test “in accordance with procedures” should be at 350 millibars, as opposed to the “70-75mb” referred to in Mr Doyle’s message.
But he said that even this “less stringent” pressure test would have sufficed to detect the “bigger leak” emanating from Haut du Mont within approximately 6-7 minutes.
“The odds of someone having done something else on the system are pretty low,” he continued. “I think it was reasonable, to me, at that stage to do a quick and easy test just to see that nothing major had actually been caused on that system during that work.
“The whole process, I’d say – in my view – it was adequate: not the best, not brilliant, not best practise, but it would have done the job.”
The court heard him say that the decision not to apply any sort of pressure test was the “major cause” of the fatal Haut du Mont explosion.
“All those failures up to that point,” he said, “those had not caused injury, or explosion, to anyone or anything.
“What really caused a problem was they then admitted gas to the system that had got an opening without doing the simple pressure test to find out whether it was OK or not.
“In my view, that’s what the major cause of the release of gas that was involved in the explosion was.
“Not everything else that led up to that point: it was that one failure to do a pressure test before admitting the gas to the system.”
Advocate Olaf Blakeley, representing Mr Ward, argued that the most significant failure was Mr Armstrong – his client’s supervisor – failing to close and plug the gas valve at Haut du Mont.
“The pressure test is the safety procedure that doesn’t assume that all the previous work has been done correctly”, Mr Siddons countered.
Commissioner Andrew Oldland is presiding.
The trial continues.
