A father died following a blast at a chemical plant where he was working with his son, an inquest heard.
Contractor Robert Cranston had been carrying out maintenance work at Briar Chemicals in Norwich.
The 46-year-old senior craftsman was using a grinder, causing sparks to fly, when there was a blast, his son Owen Cranston told the inquest in Norwich on Tuesday October 27.
His son, who was also working at the site, said there was a “very loud bang”.
“I can only describe it as looking like what you can see coming out of an aircraft engine on the runway before flight,” he said, in a statement read by the coroner.
He said his father’s orange overalls were burned off and his welding mask ended up on the ground.
Self-employed pipe fitter Kevin Headford said: “There was a whooshing then a pause.
“I stood up and looked then there was a boom.”
He said he ran to the scaffolding platform, where Mr Cranston had been working to repair a water jacket, to help him.
Mr Headford said: “They didn’t expect the job to be potentially explosive.”
He added that Mr Cranston was “always sensible and reliable at work”.
Mr Cranston died in hospital on July 27 2018.
Norfolk’s area coroner Yvonne Blake said that gas monitors that were being used at the time would take over seven minutes to detect the flammable substance toluene, “whereas an ideal monitor would take seconds rather than minutes”.
Answering a jury question about whether he noticed a smell as toluene has a “distinctive odour”, Mr Headford said: “No, I was asked a similar question by the HSE.
“A chemical plant generally smells a bit chemically so unless there was a particularly strong odour it becomes part of the background smell.”
The inquest, being heard before a jury and listed to last for nine days, continues.