A worker at a wood mill where four people died in a blast said he had been sacked after raising safety concerns.
Matthew Dutton told a trial at Chester Town Hall he had been told to go home after refusing to clean part of the mill workers believed was dangerous.
He said machinery at Wood Flour Mills in Bosley, Cheshire, was never turned off, the dust in the area was up to his knees and the air was “unbreathable”.
A firm and its director are on trial over the deaths in July 2015.
The exact cause of the fatal blast is not known, but it involved wood dust.
Workers who died in the explosion were Derek Moore, of Goldenhill, Stoke-on-Trent; Dorothy Bailey, from Bosley; Jason Shingler, of North Rode, Cheshire; and Derek William Barks, of Leek, Staffordshire.
Others were said in an earlier court hearing to have received “horrendous injuries”.
Mr Dutton, who had worked at the mill as a charge-hand with his father and uncles, said: “The machinery was still operating. It’s moving objects, and using a shovel and cleaning products around moving objects could risk losing limbs.”
The jury heard manager Peter Shingler, who is charged with a health and safety offence, was “intimidating” toward Mr Dutton when he said it was not safe to clean the area.
In a statement, Mr Dutton said: “Pete said we were doing his head in and it was best we went home.
“Basically he sacked us for not cleaning the Riverside when it was dangerous to do so.”
He later got his job back when his father spoke to mill owner George Boden.
Malcolm Galloway, representing Mr Shingler, suggested the manager had got another charge-hand to turn off the machinery so cleaning could take place, but Mr Dutton said the machinery had been left on.
Another worker, Richard Wills, said the dust in the Riverside area was sometimes “packed up as tall as me” and told the court he is 6ft 1in (1.8m) tall.
He also described the explosion itself and said: “It was terrifying, like a bang inside a bang inside a bang, and just heat.”
Wood Treatment Ltd has admitted a health and safety offence but denies four counts of corporate manslaughter.
Owner and director Mr Boden, 64, of Church Road, Stockport, denies four counts of gross negligence manslaughter and a health and safety offence.
Mr Shingler, 56, of Tunstall Road, Bosley, and operations manager Phil Smith, 58, of Raglan Road, Macclesfield, both deny a health and safety offence.
The trial continues and is due to last three to four months.