A marine transportation company was fined $50,000 on Wednesday for a workplace safety lapse that led to the death of a lorry driver in 2011.

Director of Trans-Island Marine, Mr Ng Teck Hai, 52, had pleaded guilty to failing to take measures to ensure that the workplace was safe and without risks to the health of every person on the premises.

Lorry driver Lim Wei Kwan, 37, was seated in a lorry which was on a barge when the vehicle rolled down into the sea off Pasir Panjang Terminal on Dec 10, 2011. The father of four drowned.

The incident happened during the return journey from Pulau Sebarok to Singapore after he had delivered bulk containers of chemicals to the island.

At the time, Mr Lim's co-worker Mr Shaan Seloras, had alighted to go to the toilet.

When Mr Seloras realised the lorry was rolling backwards towards the ramp of the barge, he alerted Mr Lim. But Mr Lim did not have time to get off the lorry, the court heard.

Among other things, the company had failed to effectively tie down the lorry onto the barge to prevent it from moving during the sea journey.

It also failed to ensure that the vehicle's wheels were choked and handbrakes applied before commencing the sea journey.

Mr Ng said his company was no longer in the tugboat business which he had run for 30 years. He added that he had asked the driver to get out and had also tried to save him.

The maximum penalty is a $500,000 fine.