A man's body was seen flying through the air when a tank fatally exploded at an industrial site in South Auckland yesterday.
Flames and plumes of black smoke erupted from the 100,000-litre tank and debris was strewn hundreds of metres - one huge piece crushing the roof of a car when it landed in a yard.
A contractor who is believed to have worked for RaceWorks in Huntly was killed in the 1.36pm blast at Salters Cartage, a hazardous materials recycling business on Bolderwood Place, Wiri, which also specialises in fuel and chemical delivery, and hazardous liquid storage.
Four other people suffered minor injuries.
The explosion rocked buildings kilometres from the scene and sent eyewitnesses diving for cover. It was so violent that one nearby worker thought an aircraft had come down.
Salters Cartage managing director Ron Salter said two contractors had been on site, measuring some walkways.
One decided to do some welding, without permission, causing a tank to explode.
The blast shattered the peaceful spring afternoon, blowing out all the windows at Salters Cartage and sparking a full-scale emergency response from fire, ambulance and police that saw cordons erected and the accident site locked down.
Stunned workers milled at the cordon and traffic backed up in long queues.
Counties Manukau Police area commander Inspector Julia Lynch said the dead man's co-workers who saw the incident were shocked.
"Obviously they're devastated, they're upset," she said.
The force of the explosion blew photos off walls a block away, shook buildings and was described as sounding "like a bomb".
Where it happened:
Witnesses spoke of running for cover from airborne debris, seeing flames leap 30m into the air and feeling buildings shake 10km from the blast site.
One man, who asked not to be named, saw "the guy fly high in the air with the explosion".
He and a friend dived under a nearby container to avoid all the flying objects.
Jason Farquhar witnessed the explosion and told One News he saw a man standing on the roof of a petrol container. He described the container as being like a silo and said the man appeared to be welding.
Mr Farquhar heard "a pretty big bang ... like a sonic boom" and saw a "shockwave" when the explosion occurred.
The person on top of the container was thrown in the air far away from the container, he said.
Meanwhile, a relative of a Salters Cartage worker who saw the incident unfold said his family had gathered around to support him last night as the scenes he described had been traumatic. The worker witnessed the moment of the explosion when the man was thrown from the tank.
"He is very emotional at the moment. He hasn't said much about it, but he saw the [man] who was on the tank. He's upset about that and finding it hard to deal with at the moment."
The relative - who asked not to be named - said their family member had described "other things" that they did not want to discuss publicly out of respect for the dead man's family.
"He's at home now, but he's just very emotional. We're all supporting him and will be supporting him over the next few days."
She added it had been a long wait before the family were informed that their relative - as well as several other workers they had links to - were unharmed.
"It could've been bad for us and we were very worried."
Terrance Matthews, who works at ABC Tissue on Roscommon Rd, said a set of roller-doors about 12m by 8m shook violently when the explosion happened.
"I thought someone had hit one of the columns, it was so violent, and we are like a kilometre away."
TransDiesel service adviser Peter Swann said his office building "shook like crazy".
"We thought it was a plane gone down."
A man who worked around the corner from the factory also said the explosion shook his office.
"And massive pieces of debris were visible in the air immediately afterwards.
"There was a strong smell of gas in the area as well," he said.
The incident is now under investigation by police, the Fire Service and WorkSafe NZ.
Specialist fire investigators and dozens of emergency crews were sent to the scene after the blast.
Roads around the site were closed for a time and cordons remained in place last night at the accident site, which was under police guard.
A WorkSafe NZ spokesperson said it had been notified about the incident and was investigating but refused to give further details.
According to the company's website, Salters Cartage specialises in waste oil collection and recovery; shipping and marine collection and recovery; oil disposal; fuel and chemical delivery and hazardous liquid storage.