Class grinder may have sparked Kaitaia explosion

A student using an angle grinder may have ignited leaking gas that exploded with devastating effect in a Kaitaia classroom this week, the school's principal says.
The explosion in Kaitaia College's engineering classroom on Monday propelled tools 15m around the room and embedded them in a blackboard and wall. A tool was also launched through wire-mesh safety glass.
Students lay bleeding in the classroom after the blast, which shattered most of the room's windows and was heard throughout central Kaitaia.
Six students from the year-11 metalwork class and one teacher were taken to hospital, four sustaining critical injuries.
Mr Tailby yesterday told The Northern Advocate the "most logical" explanation for the blast was leaking acetylene gas from welding bottles stored at the back of the classroom.
The explosion happened about 1pm in the class of 18 boys, a teacher, and a teacher aide. The incident happened only 10 minutes before the class was to end.
"A boy at the back was doing angle grinding so perhaps gas had been building up and a spark from the angle grinder ignited it," Mr Tailby said.
He said the students had not been using gas at the time.
The classroom yesterday looked like a bomb had hit it. Tools had shot 15m to the front of the class into a blackboard, window and wall, wall cladding was blown off both sides of the wall where the explosion occurred and blood was left smeared on the floor at the front of the room.
Behind the wrecked back wall, a car used for automotive engineering was seriously damaged and a dusty clock lying at the front of the class was stopped on 1.15pm.
Mr Tailby said that when he arrived at the classroom after hearing the blast from his nearby office he had not been prepared for the destruction he saw.
It was a miracle only six students were injured, he said. "I had no idea it was going to be as bad as it was."
He said students had been bleeding and he had been told the teacher aide had been thrown across a work bench. "He's a big boy and he was halfway up the classroom," Mr Tailby said.
Yesterday the 12 other students and teacher aide involved in the incident spent the day together getting help from Victim Support and other agencies. The rest of the school was running to normal routine.
Mr Tailby said the teacher, who is in Whangarei Hospital, was a "bit distraught". The 12 other students in the class were "talking" about their experience.
Mr Tailby praised the school's teachers and 830 students for the way they had dealt with the blast. He said the pupils had remained calm when they were evacuated from classes and acted maturely.
Schools, even including Timaru in the lower South Island, had sent Kaitaia College faxes and flowers expressing support and locals had even shouted morning tea for staff. "Other schools and the community have been incredibly supportive - it's really great," Mr Tailby said.
A woman living across the road from the school told The Northern Advocate she had been spooked by the "deadly silence" that fell after the explosion.
The elderly woman, who did not want to be named, said she had been lying on her bed at the back of the house when she heard the blast. She then heard a "tinkle of glass".
She thought it was a transformer that had exploded but soon realised it came from the college when ambulances and fire engines turned up. "The thing that struck me was the deadly silence straight after the explosion. There was no screaming or yelling," she said.
A gas investigator was due at the school today.