As he spoke publicly for the first time, the shop teacher who was supervising Eric Leighton the day he was killed apologized for what happened.
"I'm just very sorry it happened," Scott Day said as he finished his initial testimony.
Day said he wasn't aware the boys would be cutting a barrel the day Leighton was killed and that he never gave permission for that to happen.
He said he cautioned Adam Soliman he and Eric Leighton may have needed to use a hack saw and not a grinder to cut the barrel. He said it was something he'd intended to research further before letting the pair cut the second barrel.
He didn't give specific instructions for working with closed containers because, he said, he himself was only aware of the general safety concerns.
"I'm not going to teach something I don't have formal training on myself," said Day.
He said the pair of boys were not even supposed to cut the barrel the day Leighton was killed.
Day testified he thought they were only measuring and marking the barrel and was confused when he heard the explosion.
It was Day's instructions to use the aerosol cleaner to remove old peppermint oil from the barrel. That cleaner is what engineers say ignited in the explosion, not the peppermint oil.
Earlier Tuesday Adam Soliman testified he thought Leighton had obtained permission to start cutting the barrel.
He also testified he used the aerosol cleaner about 10 times and rinsed it only with water from a hose in the shop classroom.
Day will continue testifying Wednesday when lawyers for the Ministry of Education will be among several parties with a chance to cross examine him.