Three former gas workers and the island's gas company are going on trial over the deaths of 10 people in an explosion at Haut du Mont in December 2022.
This complex investigation, dubbed Operation Spire, has taken almost four years to come to trial.
It has in fact been two major probes, running in parallel - one by States of Jersey Police and the other by the Health and Safety Inspectorate.
Neil Armstrong, Lee Ward, and John Wright, who were employees of the gas supplier at the time of the fatal blast on Pier Road in St Helier, are charged with gross negligence manslaughter.
Island Energy is being prosecuted under the Health and Safety Law.
All the defendants deny the charges.
The trial begins this morning (7 September) and is expected to take up to 12 weeks.
After today's jury selection, the case will be heard in a new courtroom created at Jubilee Wharf.
Ten islanders, Peter Bowler (72), Billy Marsden (62), Derek Ellis (61), Sylvia Ellis (73), Ken Ralph (72), Jane Ralph (71) Romeu De Almeida (67), Louise De Almeida (64), Raymond Brown (71) and Kathy McGinness (73) were killed in the explosion at Haut du Mont on 10 December 2022 just before 4am.

Fort Regent vision 'was never matched' by a budget that could deliver it, says JHA
Buzzing! Bears and Bees coming to Jersey
JCG Year 7 Choir learn and perform wartime song
Gas bills to go up by 5% in December
Second memorial plaque vandalised at Millennium Park
'They got our hopes up': Young islanders disappointed as Fort Regent plans stall
Electricity prices in Jersey to rise by 2.5%
Minister says he has been 'slated' and his family taken 'abusive' phone-calls over economic growth comments