The employee had been working for Rygor Commercials at Hambridge Business Park in Newbury, Berkshire, when an empty oil drum he was cutting up exploded on 5 January 2017.
Reading Magistrates' Court was told that the worker was using an oxy-acetylene gas cutter when the flame ignited vapours inside the drum, causing it to explode. The lid struck the worker's right leg and the main body of the drum landed about 20 m away.
The Health and Safety Executive (HSE) found that the company did not have a safe system of work for disposing of a stockpile of empty oil drums. On its website, Rygor Commercials describes itself as the "largest dedicated dealer group for Mercedes-Benz commercial vehicles in the UK."
It had not identified the risk of fire and explosion from flammable vapour residues inside the empty drums, nor had it communicated to its workforce the risks of using oxy-acetylene gas equipment.
Rygor Commercials pleaded guilty to breaching s 2(1) of the Health and Safety at Work Act and reg 5 of the Dangerous Substances and Explosive Atmospheres Regulations.
Accounts filed for the year to 30 April 2018 show the company had a turnover of £232.5m, putting it in either the "large" or "very large" organisation category under the Sentencing Council's guidelines.
HSE inspector Nancy Harman said: "If a suitable safe system of work had been in place prior to the incident, the life changing injuries sustained by the employee could have been prevented."