POLICE were still investigating today after a smoke bomb exploded in a Calderdale school, putting nine pupils in hospital.
More than 1,000 youngsters, some choking on fumes, spilled from Calder High School to the safety of playing fields yesterday when part of the building was engulfed in smoke and a small fire broke out.
Police have charged a 16-year-old boy from the Mytholmroyd school with arson and he will appear in court next week.
Fourteen pupils had to be checked for smoke inhalation and nine were taken to Calderdale Royal Hospital by ambulance. Six ambulances and police attended.
Pandemonium broke out around 9am, shortly before an assembly scheduled for fifth-formers breaking up on exam leave. It is believed the incident was an end-of-term prank that went horribly wrong.
One of the fifth-formers took the industrial smoke bomb into school and was caught on closed-circuit television dropping it on a corridor floor, next to a classroom door. Hebden Bridge retained fire station crew manager Peter McGibney said a lad could be seen running away as the device was about to explode.
He said: "Within a second the whole corridor was engulfed in smoke. The intense heat started a small fire on the floor.
"One lad sounded the fire alarm instantly, which gave people time to get out.
"If the lad had been holding the smoke bomb at the time it would have taken his hand off - it was that powerful.
"It could have caused serious damage if someone had been standing next to it."
Of the smoke device, he said: "They should be hard to get hold of. This was not a toy and has caused serious damage."
Pupils were evacuated for an hour and a half while firefighters pumped smoke out of the school.
Headteacher Steven Bell said the pupil involved was now in the hands of police.
He said recently installed cameras had worked well and captured the whole drama.
He said: "It was a prank that caused rather a sad end to the year.
"We have had 14 kids looked at by paramedics and several were taken to hospital.
"It is something we deeply regret but I am very, very pleased with the way the school was evacuated."
Some of the younger pupils had been very distressed, he said.
A spokesman for Calderdale Royal Hospital confirmed nine pupils were treated for smoke inhalation before being sent home.
School governor James Allison said high jinks always happened on the last day of term but this was far more serious.
Sue McMahon, Calder-dale NUT secretary, said it was a serious incident that had caused disruption to a lot of people.
She added: "I am sure the school will take appropriate action.
"But the question needs to be asked why and how a pupil managed to obtain a smoke bomb. Who in their right mind has given that to a child?"