Work on gas pipes the day before a fatal explosion in Jersey was done "not just carelessly but exceptionally badly", a court has heard.

Gas workers Lee Ward, 59, Neil Armstrong, 58, and John Wright, 60, have each pleaded not guilty to 10 counts of gross negligence manslaughter over the deaths of 10 residents at the Haut du Mont flats in St Helier following the blast on 10 December 2022.

The manslaughter case is being combined with a health and safety case against gas company Island Energy (IE) at Jersey's Royal Court.

Chief executive Graeme Millar, on behalf of the company, has pleaded not guilty to two counts of failing to keep people safe during the events around the explosion.

The residents who died included:

Prosecuting, Advocate Simon Thomas, said gas had escaped from pipes which had been worked on by Ward, Armstrong and Wright on 9 December.

He said IE "failed to ensure the health and safety" of both members of the public and its staff and "didn't properly supervise or check the work that its employees were carrying out".

"Such was the failure that the explosion was an incident that was waiting to happen," Thomas said.

The prosecution said there had been planned work by IE to disconnect the gas supply from the Haut du Mont flats "in its entirety".

The flats, which were owned and managed by Andium Homes, were supplied with gas from IE's plant at La Collette.

The prosecution said Andium was in the process of arranging for the gas supply to be disconnected from all its properties.

In its opening statement on the first day of a trial expected to last at least two months, the prosecution explained how gas was supplied to homes and businesses in Jersey.

Images were presented to the court showing how pipes led from a low pressure main outside Commercial Buildings, up a wall and under the road above to the flats.

The pipework also flowed south supplying gas to other properties at La Collette, including DVS, the St Helier Yacht Club and IE's own premises.

The prosecution said most flats at Haut du Mont had ceased using gas "a considerable time" before 2022.

It said Andium Homes had wanted the gas supply to all of its properties "to be cut" - three gas meters were still in place as of summer 2022, with one flat still using a gas cooker.

Ahead of planned work, it said the remaining meters were removed and the gas cooker replaced with an electric one.

By December 2022, none of the flats at Haut du Mont were using gas, Thomas said, although he added there would still have been gas "flowing up the riser and into the pipework at the development".

He said gas was stopped from escaping by emergency control valves and plugs in the end of the pipes.

He said the "easiest approach, you may think" would have been to cut off the supply just outside the flats, but said, if it had been disconnected there, gas still would have remained in the pipework.

The prosecution said it was decided to disconnect the supply down at Commercial Buildings before the riser which went up the granite wall.

He said Armstrong had begun this work alongside Andium Homes back in August with plans to carry out the works on 9 December.

Wright carried out the work with his assistant, who then left and was joined by Ward.

Thomas said difficulties arose during the works as Armstrong and Wright believed a T-shaped pipe that branched off to the riser was "much further back towards the road", and similarly believed the pipe that ran down to La Collette was further back towards the road.

"They failed to establish its true position and, as a consequence, cut a pipe which led to Haut du Mont and also branched off to La Collette," he said.

Thomas said the men should have cut elsewhere and that they had "guessed" where to cut it without proper excavation to show what pipework was in the ground.

He said Armstrong "failed to carry out basic tests" and did not understand the layout of the pipework which was "the first error" his team made.

The court heard that work carried out by Armstrong and Wright did not comply with IE's work procedures and that it was "sloppy, unsafe and cut corners".

It did not cause the explosion, Thomas said, but it gave an idea of the "lack of care that was taken over the work that was being carried out".

When Wright cut the pipe, Armstrong went to Haut du Mont to check the gas supply had stopped and was "satisfied" it was. However, at noon, St Helier Yacht Club called IE to say it had lost its gas supply.

Thomas said there was initial "puzzlement" but the men realised that they had cut off the supply for both buildings.

He said reintroducing gas again should not be rushed, and checks should be made as to why gas had been lost in the first place.

The prosecution said Armstrong told investigators that he felt "pressured" by the yacht club to reinstate gas into the network and restore its supply.

Armstrong said he went up to Haut du Mont between 14:30 and 15:30 to make sure plugs that would prevent gas escaping were in place and all gas cupboards were closed, but Thomas said "he failed" to ensure this.

Thomas said "at least" one valve was open and another unplugged.

"It could've been identified even after Mr Armstrong had left" if the team had undergone a pressure test on the pipework, Thomas said, which would have ensured no leaks on a network where gas was about to be reintroduced.

Prosecutors said Armstrong had told Wright to not carry out the test and to "get it [the gas] back on".

The court heard two senior managers had told Armstrong to do a pressure test but he did not.

Thomas said Armstrong later on "lied" to one of his managers, saying he had done a pressure test.

Once pipework was reconnected to the St Helier Yacht Club, gas was also reconnected to Haut du Mont, escaping through one of the opened valves.

Later on, at about 20:30, members of the public reported the smell of gas in the vicinity, with the fire service attending. A resident of the flats also called reporting the smell.

An on-call duty engineer also attended the excavation site at Commercial Buildings, not Haut du Mont, but fire crews told him he could "stand down".

Thomas reported a "series of missed opportunities" to "avert the disaster" on behalf of IE, the emergency call room and the fire service.

The States Employment Board has pleaded guilty to offences under the Health and Safety law on behalf of the fire service and the control room in respect of those failings and is due be sentenced at the conclusion of these proceedings.

The gas that had continued to escape made its way into the block of flats, subsequently causing the explosion at about 04:00.

Its trigger is unknown.

Thomas said many IE engineers attended the scene at the offices at La Collette and said "several" heard Armstrong "accept" the cause of the explosion was most likely "his failure" to ensure caps were in place on the valves they had worked on the day before.

Speaking about IE, the prosecution said it ran its business in a way that put its staff and members of the public "at risk", with a "lack of management" and "lack of supervision".

It said IE did not properly plan ahead of work being carried out, did not stop work for investigations to take place if issues arose, and that its policies were inconsistent and lacked detail.

Thomas also said IE had "lied" in the steps it took when the public reported the same of gas and sent an "inexperienced" person who had not been recently trained to investigate it.

The prosecution also found, according to IE's own policy, that work should not take place on a Friday or bank holiday to ensure there would be another working day to address any issues if anything unexpected occurred.

Excavation work had taken place to disconnect pipework on Friday 9 December as part of plans to cut the flats off from gas services.

Thomas added that "a significant number" of senior IE staff were off island on 9 December.

The trial, being held at the Royal Court Rooms, continues.

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