A pressurised gas cylinder was put through a shearing machine for processing on 16 June 2009 when it exploded. Tony Johnson, 55, was hit in the head by a large section of the cylinder and died from his injuries.
The Health and Safety Executive's (HSE) investigation found Walter Heselwood had not adequately assessed the risks from handling different types of scrap metal and failed to implement appropriate measures to minimise these risks, such as installing a blast wall.
HSE inspector Kirsty Storer said "an assessment should be carried out to determine any additional precautions that might be required, such as a pit or blast wall", adding that these safeguards need to be well maintained.