Nylacast worker Tarsem Singh died of a heart attack in hospital on 16 April 2016, a day after he sustained the strike, which was the equivalent to the force of eight tonnes, The Leicester Mercury reported.
A Health and Safety Executive (HSE) investigation found that the 52-year-old employee was in the process of removing the plastic component from a casting machine when the incident happened at the firm's Thurmaston Boulevard site in Leicester.
The rod was secured in the machine by a pressurised piston, which should have been depressurised before the rod was removed. As Singh was removing the rod, it was forcibly ejected along with the machine's retaining end cap, striking him in the chest with significant force.
Leicester Magistrates' Court was told in July that Nylacast had failed to undertake a suitable and sufficient risk assessment of the long-length rod machine. The firm employs 125 people at the site, staffing a 24-hour operation.
The firm pleaded guilty to breaching reg 3 of the Management of Health and Safety at Work Regulations 1999 and reg 12 of the Provision and Use of Work Equipment Regulations 1998. In addition to the fine, Nylacast must also pay £10,206 costs.
District Judge Daber, who was sentencing at Northampton Magistrates' Court on 3 December, said: "There was no engineering measure which prevented the ejection of the end cap before pressure in the mould had been released.
"The failings in this case were not an isolated incident as the risk existed each time the machine was used. In this court's judgment, this was an accident waiting to happen."
A statement from the firm, Nylacast said it had co-operated with the HSE throughout the investigation and pleaded guilty at the first opportunity.
"Safety is always our number one priority, and as we do with any incident or observation, our practices and protocols have been and are continually reviewed to ensure the wellbeing of our colleagues," the firm said.
"Operational meetings, staff inductions, process development and training all begin with safety and have safety metrics and audits integrated within them."
