The fire officer investigating Friday's blaze at Eastown Timber says seeing CCTV footage and understanding the way alarms were activated might determine its cause.
The fire that broke out at Eastown Timber & Fencing early on Friday morning destroyed its treatment plant, paint line and planer, but was prevented from spreading to other buildings.
Fire and Emergency NZ risk reduction adviser John Hotter has the job of investigating it. He was at the scene soon after fire broke out and stayed there all day, watching the way the fire burned and its pattern.
Hotter said he wanted to see CCTV footage taken from inside the building. It could show which end of the building the fire started.
The way the building's fire detectors were activated could also be significant.
The nature of the fire and the chemicals that were involved meant it wasn't safe to do on-site investigation amid the debris, he said. Also, the two diggers that were needed to break apart burning packets of timber had destroyed some evidence.
Hotter wouldn't speculate about the cause, except to say it could be related to electricity. He didn't believe the fire was suspicious.
"We may never know exactly what caused it."
It's a similar outcome to the investigation of the fire that destroyed the Thain's building at 1 Victoria Ave in July 2019. That fire went to fourth alarm and severely injured one of the building's two occupants.
New Plymouth specialist fire investigator Matt Crabtree led its investigation.
"Due to extensive damage to the building and the building being unstable and a collapse risk, no internal investigation was completed," he said.
No conclusion was reached about the cause of the fire.