Warning: This article contains graphic information that some people may find upsetting.
Howard Miller, 39, was killed in a welding explosion after mixing two compounds and inadvertently creating a bomb that shook West Auckland.
On Monday evening the huge blast rattled the suburb of Henderson, shattering the windows of neighbouring properties on Universal Dr and Don Buck Rd.
Josh O'Neill has spoken to the Herald exclusively about the moment his friend died. He wants to quash rumours the explosion had been caused by a clandestine P-lab.
"We were going to use it to bend the manifold. But you can't mix the two at all."
The two are normally kept in two bottles, each of which has a regulator, the two components meet at the welding torch causing the chemical reaction used to cut or weld.
"He didn't realise he had made a bomb," O'Neill said.
Miller had taken the regulator off the bottle which prevents oxygen or other chemicals coming back into the bottle.
"I knew not to mess with it, he tried to get me to stay, he asked me three times."
Miller then tried unbolting the regulator on the tank and tried to attach the gas torch head straight onto the bottle.
"To make it fit without the hoses, he had adapted the bottle."
Miller grabbed some pliers off the shelf, then O'Neill started to feel wary and said he was going to step aside.
"I said, 'I'm out of here'. I knew not to mess with it. It is crazy."
O'Neill said he walked out next to his car and heard a small bang.
Miller's van was still sitting out front of the house today, haunting him, O'Neill said.
The Herald has sought comment from Fire and Emergency New Zealand and police.
Detective Senior Sergeant Callum McNeill confirmed this afternoon that Miller had gone to a friend's house to help weld an exhaust onto a car.
"There has been speculation on social media that the explosion was a clan lab, however that is not the case.
"The matter has been referred to the Coroner."
Lower Don Buck Rd superette co-owner Kanchun Chauhan said earlier this week she had been working at the shop when she heard a massive thud and the entire building was shaken.
"The impact was pretty immense, it was a massive thud. The smoke that billowed up was pretty big."
A woman living next-door at number 2 Don Buck Rd told the Herald she had been watching television with her four young children when the explosion happened. The force of the "frightening" blast smashed part of her back door window.
She immediately ran out of the house to see what was going on, finding the older woman, who lives at number 4, standing by the letterbox.