WorkSafe has been accused of not doing enough to investigate what happened on the night Peter Watson died at a Wodonga metal foundry.
Defence barrister Robert Taylor used his closing address at Wangaratta County Court on Tuesday to tell the jury in the trial of Bradken Resources that the WorkSafe investigators lacked the required background knowledge of the industry.
There were no witnesses on the night of July 22, 2014 when a hot 300-kilogram metal casting fell from the bucket of a skid steer loader back onto Mr Watson, who was operating the machine, causing it to set on fire.
Prosecution expert witnesses told the court there was no way to know exactly what happened.
"These two witnesses were witnesses of utter desperation," Mr Taylor said.
He asked the jury to find Bradken not guilty of the charge of failing to provide a safe workplace.
"This is unprecedented ... Yes, this shouldn't have happened, which is why Bradken has tried so hard to understand it," he said.
"We certainly don't dispute the tragic nature of the incident."
Bradken workers giving evidence during the trial told of examples where a small piece of metal or sand had fallen back from the skid steer loader.
Mr Taylor said these were just "discreet risks", but prosecutor Andrew Palmer argued they meant Bradken should have seen the risk that a casting could fall back onto the operator - and chosen to use an excavator instead.
"You shouldn't wait for an accident to happen," Mr Palmer said.
"If there's a risk an employee could be burnt to death and there's something that could be done to reduce that risk, then of course you should do it."
The evidence of defence expert witness Roger Kahler was contentious, with Mr Palmer accusing the engineer of trying to help the defence, rather than be impartial.
At one stage, Mr Kahler - a regular expert witness in court cases - admitted he was "always one trial away from being discredited".
"Mr Kahler is here to defend his reputation, his living as an expert witness," Mr Palmer said.
"He's not going to concede anything that's going to help the prosecution case."
But Mr Taylor said the prosecutor's attack on his witness was "desperate".
"Mr Kahler destroyed his case comprehensively," he said.
The barrister said the case was never about putting the blame on Mr Watson himself, but finding out what happened, which was why Bradken executive general manager Brad Ward was in court for every minute of the trial.
The jury is expected to start deliberating over the verdict on Wednesday.
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