Second worker dies after toxic gas incident at PUB's Choa Chu Kang Waterworks

SINGAPORE: A second worker died on Tuesday night (May 28) after inhaling toxic gas at PUB's Choa Chu Kang Waterworks last week.

The 24-year-old Malaysian, who was an employee of PUB's contractor Stargroup Est, was admitted to intensive care after the incident on May 23. He died of his injuries on Tuesday, said PUB on Wednesday.

He and two other workers had collapsed after inhaling hydrogen sulphide gas while draining sludge from one of the plant’s pulsator tanks as part of tank cleaning work.

Hydrogen sulphide is a gas produced from sludge, which is a by-product of the water treatment process. It is a colourless gas with a potent, unpleasant odour, and is highly toxic and flammable.

All three workers were taken to Ng Teng Fong General Hospital where one of them, a 40-year-old Indian national, died the same day.

The other two workers, both Malaysians, were warded in intensive care.

The 24-year-old Malaysian worker "received all necessary medical treatment but unfortunately, succumbed to his injuries at around 10pm on May 28", said PUB, Singapore's national water agency.

The remaining worker, a 39-year-old, was moved out of the ICU on Tuesday. His condition is currently stable.

PUB expressed its deepest condolences to the family and loved ones of the deceased worker. 

"Together with our contractor, we are doing everything possible to support his family during this difficult period," it said.

In response to CNA's queries, Stargroup said on Friday that it was "actively assisting the family by expediting the claim process" for compensation after the worker's death.

The employer said it has engaged an undertaker to ensure the deceased worker's body is "respectfully sent back to his hometown".

PUB said that it is cooperating fully with the Ministry of Manpower on its investigation and is conducting a safety investigation of its own.

"We would like to seek the public’s understanding that we are unable to provide further information on the incident at this juncture," said the agency.  

As part of its safety timeout, PUB said it has been reviewing safety protocols, especially those pertaining to work in confined spaces where there is the risk of exposure to toxic gases and chemicals.

It is also reinforcing the importance of following procedures to ensure the safety of its employees and contractor workers. 

"We have been progressively lifting the safety timeout at worksites and plants where we are satisfied that the necessary and appropriate measures are in place," said PUB.