Six boys died and thirty were injured because a live grenade was mixed in with dummies used for training.
The boys were teenagers at the time, and were told to keep quiet about the incident.
Paul Wheeler was an instructor at the camp. Last year, he travelled to Saskatchewan for a commemoration event to mark the 40th of the tragedy. He says even though he was not physically wounded, the emotional scars persisted.
"I walked through the door and my mum looked at me and said 'Oh, I'm glad you're okay," he said. "And because physically I was, but I didn't tell her about the recurring nightmares and dreams and things. So I just nodded my head and said yes, I'm fine. I think it happened to almost everybody in the same way."
The National Defence ombudsman announced in May 2014 he would investigate.