KEY POINTS:
Expert investigators are confident they will find out what caused an explosion that killed a senior Hamilton firefighter despite massive damage to the building where it occurred.
Derek Lovell, 49, died and seven of his crewmates were injured after the explosion at Icepak Coolstores in Tamahere, southeast of Hamilton on Saturday.
A team of investigators is continuing to rifle through the rubble today.
Four Fire Service investigators - including Inspector Bob Alexander from the Fire Investigation and Research Unit which is part of the New South Wales Fire Service in Sydney - have been at the scene for days.
Speaking to the Herald at the scene yesterday, Mr Alexander said the construction of the building was one of the "issues" under examination after the explosion, which sent a 2000km/h blast wave through the area.
Mr Alexander said he was confident investigators would work out what had happened. Evidence gathered would include burn pattern indicators, which would show where the fire had come from and where it spread, as well as the blast damage.
Experts could tell if the piles of twisted steel remains had become buckled due to heat from a fire, or if the explosion itself caused the damage, which then led on to the fire.
He said no one had reached a decision yet on what had happened.
"Every day we're gathering information and every day we get closer."
Investigators were also looking into the history of the building - and how it had been constructed - to see how much that had contributed to the blaze.
The building was made with "sandwich panels" - polystyrene with outer layers of metal - which he said were "volatile".
"The polystyrene will melt and move away from the fire, but as it moves away from the fire it gives off volatile gases."
Information would also come from the firefighters involved and from analysing the scene.
News photographs of the scene and firefighter and witness accounts of what happened would also be collated.
Mr Alexander said the Tamahere fire differed from the fires he was usually sent to around NSW because of "the gravity of the situation" with the loss of a fellow firefighter.
News of Mr Lovell's death had been felt by firefighters in Australia because firefighting was like a worldwide community, he said.
He had jumped at the chance to help out his Kiwi counterparts.
"We want to find out what happened to prevent it happening to any other firefighters."
Seven more private fire investigators from insurance agencies are also piecing together the puzzle to work out what caused the explosion.
The Department of Labour and police have also had representatives at the site.
The incident controller, Acting Rotorua Chief Fire Officer John Booth, said four small fires were still smouldering away yesterday in the ruins of steel, cheese and meat.
Firefighters need to remove the meat from the scene before it becomes a rotting health hazard.
