Luke MacMaster to remain in military detention after review upholds explosion sentence

A review has examined the punishment imposed on an army instructor, who caused an explosion that burned a trainee at a Sydney barracks. Find out the result.

Luke MacMaster outside the Defence Force Magistrates Court in Canberra in April. Picture: Blake Foden

A former army instructor will remain in military detention following a review, which upheld the punishment imposed on him after he caused an explosion that burned a trainee.

Luke Thomas MacMaster, 31, was sentenced in the Defence Force Magistrates Court last month to 120 days in military detention, with the term to be suspended after 40 days.

The sentencing magistrate, Major General Michael Cowen KC, also reduced MacMaster’s rank from corporal to private after convicting him of negligence in the performance of duty.

Major General Cowen did so after being informed a demotion would prevent MacMaster continuing to work as an instructor at the School of Military Engineering.

MacMaster held that position in July 2023, when he was appointed the ammunition safety supervisor for a day of training exercises at Holsworthy Barracks in Sydney.

Luke MacMaster, centre, speaks to his lawyers outside the Defence Force Magistrates Court last month. Picture: Blake Foden

The court heard he told a colleague during the day that he had “a surprise for the fire later”.

He eventually delivered on that promise, placing a cardboard box that contained about 200 grams of gunpowder onto a campfire as trainees relaxed nearby at the end of the day’s exercises.

Luke MacMaster is a member of the Australian Army. Picture: Alix Sweeney

“Surprise, watch this,” MacMaster told the trainees before walking away towards a bunker.

The gunpowder subsequently exploded, unleashing what a prosecutor described as “a fireball”.

The blast landed one of the trainees in Concord Hospital, where he underwent surgery after suffering burns to his face, head and neck.

While the trainee did not sustain any permanent scarring, the court heard he had some “blemishes” on his face.

MacMaster was initially charged with engaging in dangerous conduct with recklessness as to the consequences.

When prosecutors elected not to proceed with that charge, he pleaded guilty to the lesser offence of negligence in the performance of duty.

All convictions imposed by the Defence Force Magistrates Court are subjected to an automatic review.

A newly published case summary shows the reviewing authority in this case handed down its decision earlier this month, upholding MacMaster’s conviction and punishment.

MacMaster, who is originally from Rockhampton in central Queensland, is set to be released from detention next week.