An experienced pipe fitter died of severe head injuries while working in Invergordon, Scotland on 19 June 2011, the Health and Safety Executive reports.
The fatal accident occurred when the man, working alongside two other colleagues, was constructing a section of pipework on a newly-fabricated subsea valve assembly for JPR Fabrication Limited.
During installation of the pipework, six plates securing one of the structure's connection porches, each weighing 1.7 tonnes, had been removed leaving it unstable.
The experienced professional continued to work on the partially installed pipework when the unsecured porch fell from the assembly. He lost contact with the structure and fell - the porch landed on him.
He sustained serious injuries to his leg and head. The man, aged 55, succumbed to his multiple injuries and sadly died as a result.
Health and Safety Executive Inspector Iain Sutherland, speaking after the investigation into the workplace accident, said, "This tragic incident would not have occurred if the risk of the porch toppling had been properly assessed before the securing plates were removed, and time taken to devise and implement an alternative safe system of work for moving the porch."
Following the incident, JPR Fabrication carried out an internal investigation and formulated an action plan to review the company's use of risk assessments and operation methodology.
The Aberdeen-based business was fined £135,000 after pleading guilty to breaching section 2(1) of the Health and Safety at Work Act 1974.
It is not known if the man's relatives will make a claim for compensation.