LATEST: The man who died after boiler explosion at a school north of Auckland yesterday has been named.
He was the school's caretaker and Orewa resident Richard Louis Nel, 59.
The explosion happened at Orewa College at 2.40pm yesterday.
Middlemore Hospital confirmed Mr Nel's death this morning.
Mr Nel had been transferred to the hospital's burns unit last night after he and another man injured in the explosion were flown to Auckland Hospital by Westpac rescue helicopter yesterday.
St John Ambulance spokesman Murray Bannister said he was understood to have had burns to 90 per cent of his body.
A second man, Robin Tubman, of North Shore-based Tubman Heating Services, reportedly went into the boiler room to get access to a power point, which is when the room exploded.
Mr Tubman suffered extensive facial injuries. He is in an induced coma on life support at Auckland Hospital. Emergency surgery was carried out last night to remove blood clots, and he is in a stable condition.
Investigators said this morning it was too early to tell what caused the fatal explosion and fire.
Fire safety officer Ray Coleman said he and Department of Labour investigators were back at the scene today.
Mr Coleman, who is trying to determine the cause and the source of the fire, said it was too early to reach any conclusion.
He spent about three hours at the school yesterday gathering information before darkness fell.
"It's early days," he said.
"That's why we closed down last night. It was just too dark to even be hypothesising. You start doing that and you find yourself going down the track you don't need to be going down."
Mr Coleman expected to remain on site for the rest of the day, while the department, which investigates all workplace accidents, could be there for a few days.
Orewa College Deputy principal Mark Quigley said the school had problems with its boiler on Tuesday and called in contractors Tubman Heating Services to take a look at it.
One of the contractors and Mr Nel were in the boiler room doing maintenance when the "steam explosion" happened, he said.
A witness said the explosion broke thick glass windows and lifted up a portion of the boiler-room roof. "The whole school shook," he said.
Mr Quigley said a second contractor was outside the boiler room and was unhurt.
Mr Quigley said three staff members rushed to the injured men as soon as they heard the bang.
The school, which has a roll of about 1700, was closed today.
Parents were asked to check their emails or the school's website, or listen to the local radio station to find out whether classes would resume tomorrow.
- with NZPA