He is so guilt-ridden, he has not been eating or sleeping well since the accident happened.
Every time he closes his eyes, he sees the pained face of the worker.
The man, who gave his name only as Mr Neo, was using a forklift to move a trailer when the worker got pinned.
The worker, Mr Poh Chee Kian, 48, later died in a hospital from his injuries.
The accident took place at 9.45am on Wednesday at a Senoko Way beverage factory.
Mr Neo, 64, said he feels guilty over the death of the worker.
The prime mover driver of 20 years had been tasked with unloading a 10-tonne container of empty plastic beverage bottles.
But he couldn't do so because the trailer, with the container on it, was parked too far from the unloading bay and his forklift could not reach the container, he said.
A supervisor with a subcontractor then suggested that he use the forklift to push the trailer closer to the concrete barrier.
Just as he started pushing the trailer forward with his forklift, he heard someone shouting: "There's someone behind!"
Said Mr Neo: "I quickly moved the forklift with the trailer backwards. Then I got down to check."