David Green died in October 2016 when the dumper truck he was driving overturned at Rose Builders' Summer Park development in Essex.
He was pulled from underneath the vehicle after it fell from the top of an 11ft-high mound of soil at a building site in Lawford.
Despite initially being employed by Rose Builders as a ground worker, he soon began operating tipper trucks despite not having the required training.
A Health and Safety Executive (HSE) investigation also found that Green was not wearing a seatbelt. The spoil heap being worked on was 11ft to 12ft high, and post incident it was found to have different gradients, with some edges steeper than others.
Chelmsford Magistrates' Court was told the company had not carried out effective risk assessments into how dumper truck operators safely navigated the large mounds of soil on the site.
Other workers interviewed by the HSE said they used their personal judgement of how to tip safely, including how close they get to the edge and whether to wear seatbelts.
Investigators found tipping should have taken place at ground level, which would have eliminated the risk.
Rose Builders was ordered to pay a £225,000 fine plus £11,822 costs.
Judge John Woollard said the fine was to punish the company for its "systematic failures" to put in place safeguards which could have prevented the accident.
In a 2018 inquest into Green's death, Essex senior coroner Caroline Beasley-Murray published a report raising concerns over the incident.
"In my opinion there is a risk that future deaths will occur unless action is taken," she said. "There did not appear to be a safe system of work in operation on the site, there seemed to be a widespread practice of employees not wearing the seatbelts provided with the vehicles and there seemed to be an inadequate system of checking whether or not employees were wearing seatbelts in the course of their work."