SINGAPORE: The chief officer on a chemical tanker that was berthed in Singapore told four men to clean tanks that had not been checked and declared gas-free, resulting in the death of one of them from exposure to volatile hydrocarbons.
Dao Tien Manh had also directed and allowed the use of a modified self-contained breathing apparatus (SCBA) for the task despite knowing that this was dangerous.
Following the tragedy, he lied to the authorities on two occasions, resulting in the omission of investigations.
On Tuesday (May 19), Manh, 32, was sentenced to two years and nine months’ jail after he pleaded guilty to committing a rash act linked to the death of Hoang Van Chau, 40, a Vietnamese seaman on board the vessel GT Win.
Manh had also admitted to one count of giving false information to a public servant.
Chau had fallen unconscious in a tank that had been used to transport naphtha gas, and died from exposure to volatile hydrocarbons. Naphtha is commonly used as a solvent and sometimes as fuel for camp stoves. Exposure to naphtha can cause headaches, dizziness, nausea and vomiting.
Manh was the last of three Vietnamese men involved in the case to be dealt with in court.
In February, Nguyen Duc Nghi, then 50, who was the captain of the Vietnam-registered GT Win at the time of the incident, was sentenced to a year and two months’ jail for performing an act that could obstruct the course of justice. He had told his crew to lie to the authorities about the circumstances leading to Chau’s death.
Another man, Le Thanh Dung, then 36, who was a pump master on the tanker, was sentenced to three months and two weeks’ jail in July 2025. He had modified two SCBA masks despite knowing that they were unsafe to use when cleaning the tanks.
Deputy Public Prosecutor Joseph Gwee told the court that GT Win had sailed from Thailand to Singapore in May 2024 with tanks of naphtha gas as cargo.
After the cargo was unloaded at a terminal on Jurong Island, the vessel anchored at the Raffles Reserved Anchorage.
On May 14, 2024, Manh told Chau and three other crew members to clean some tanks that had not been declared gas-free.
DPP Gwee said: “(Manh’s) role was to check for the oxygen level in the tanks before cleaning and perform the requisite safety checks before the tanks were cleaned by the crew.
“If the tank was not declared gas-free, the crew members should not have entered the tank.”
Manh also instructed Dung to modify an SCBA mask for the men to use.
The modification involved attaching a connector of the mask to a hose linked to the valve of an air bottle on the deck.
The hose was then secured with a clamp to prevent air leakage.
The DPP said the modification was made as it was “impractical” for the men to don the heavy equipment while entering the tank owing to space constraints.
It was not stated in court documents how an unmodified SCBA mask was supposed to function, or what the standard operating procedures were.
At around 4.40pm, Manh instructed Chau to use the modified breathing apparatus to enter and clean a tank.
While in the tank, Chau fell unconscious and was rescued.
Dung then showed Nghi the modified mask that Chau had worn.
Nghi flung the mask into the sea and told the crew members to lie to the police that the incident had taken place in another tank that was gas-free.
Chau was eventually taken to Marina South Pier, where he was pronounced dead at around 10.40pm.
Two days later, Manh lied to an investigation officer (IO), claiming that Chau had entered the gas-free tank, and was later found unconscious inside it.
Manh also told a similar lie to a captain from the Maritime and Port Authority of Singapore.
Police officers later confronted Manh on May 23, 2024, and he admitted that he had lied to the IO.
The DPP said: “As a result, the police were only able to collect gas samples from the correct tank after the accused’s confession, which was nine days after the incident.”
Manh was arrested in May 2025. - The Straits Times/ANN
