A Calgary reservist accused of killing a corporal and injuring four other soldiers in a training accident in Afghanistan has pleaded not guilty to all charges against him.

Maj. Darryl Watts was charged with manslaughter, unlawfully causing bodily harm, breach of duty and negligent performance following the February 2010 incident.

The accident, which involved an anti-personnel mine, claimed the life of Cpl. Josh Baker and injured four others.

Baker, 24, was killed after the explosive device -- loaded with 700 steel balls -- was fired on a Canadian Forces platoon northeast of Kandahar city.

Baker, who was serving with the Loyal Edmonton Regiment, was in Afghanistan as a member of the Kandahar Provincial reconstruction team.

Speaking to reporters Tuesday, Watts’ lawyer said the ordeal has been difficult for his client, who was a Calgary firefighter on military leave at the time.

“It’s tough for him to give of himself for his country and then all of a sudden face possibility he could be jailed,” said defence lawyer Balfour Der.

Der maintained that Watts wasn’t personally trained with the explosive device, and was only responsible for leading the platoon to the training session.

“He wasn’t training on this explosive. He was never told he was in charge, none of those things,” said Der. “And yet after the fact they’re saying he’s responsible in the death and injuries that occurred here.”

But the prosecution said Watts’ supervision of the training range showed disregard for the safety of other soldiers and is therefore criminally negligent.

“When someone takes their troops on a range, they have a duty to make sure that that range is conducted safely. They have a duty to look after their troops,” said prosecutor Maj. Tony Tamburro.

Meanwhile, friends and colleagues of Watts from the Calgary Fire Department are in shock over the allegations.

“Darryl has always been an exemplary person in the fire department, very caring,” said colleague and Deputy Fire Chief Ken Uzeloc.

On Tuesday, the prosecution called its first witness, Christopher Lynny, who was in charge of the platoon on that fatal day. Watts was under Lynny’s command.

Lynny has pleaded guilty to negligent performance of duty. He has been demoted from major to captain and had four other charges against him dropped.

The trial is slated to last several weeks. The prosecution is expected to call close to two dozen witnesses.

With a report from CTV’s Alberta Bureau Chief Janet Dirks and files from The Canadian Press