A worker employed at a factory where a colleague died in a huge explosion has told a jury there was a blast at the plant two years before.
David Clark was giving evidence for the prosecution in the trial of Rotherham firm Sterecycle which denies corporate manslaughter.
Maintenance manager Kevin Goss, aged 58, of Dixon Road, Hillsborough; operations manager Steven Weaver, 39, of Orchard Croft, Wales, Rotherham and operations director Paul Greenwell, 52, of Bury St Edmonds, Suffolk, all deny health and safety breaches.
Goss also denies perverting the course of justice.
Michael Whinfrey, aged 42, was fatally injured in the blast in 2011.
It is alleged maintenance failures, misuse of equipment, bypassing safety devices and inappropriate repairs all contributed.
Mr Clark said the door on one of the plant’s autoclaves - large vessels which used steam and pressure to break down household waste - had not worked properly since December 2009.
He said when he started his shift on December 22 2009 there was a problem with Autoclave 2 and steam was leaking from it.
“A ten foot plume of steam was shooting up into the air,” he said.
Mr Clark said his colleagues used an ‘absence valve’ to release steam and reduce the pressure inside the vessel so the door could be opened and later that day a fitter came to investigate.
“He took the locking ring off, went to open the door and that’s when there was an explosion.
“The door blew open and all the rubbish came shooting out,” he said.
Mr Clark said the force of the blast dented a protective box around the Autoclave 1.
After the incident a different types of locking mechanisms and seals were installed to try and prevent leaks but they were unsuccessful.
Mr Clark said he told Steven Weaver it was a ‘major engineering problem not a fitters’ problem’ but Weaver thought it was a problem the fitters could deal with.
The trial continues.