Fatal gas exposure at Choa Chu Kang Waterworks: One dead, two in intensive care
In a tragic incident at Choa Chu Kang Waterworks on Thursday, one worker died and two were critically injured after inhaling hydrogen sulphide gas during tank cleaning. The victims, foreign nationals, were exposed while performing routine maintenance. Investigations and safety reviews are underway.
In an incident at Choa Chu Kang Waterworks on Thursday (23 May), a sub-contractor died, and two others were critically injured after inhaling hydrogen sulphide gas during routine cleaning operations.
The Singapore Public Utilities Board (PUB) confirmed that the three workers, all foreign nationals, were involved in tank cleaning when they collapsed.
According to local media, the Singapore Civil Defence Force (SCDF) responded to the hazardous material alert at around 11:25 am, shortly after the incident occurred at 11:15 am.
Despite immediate intervention, one worker, a 40-year-old Indian national employed as a cleaning operations manager by Supersonic Maintenance Services, succumbed to the exposure. The other two, Malaysian nationals aged 39 and 24, remain in intensive care at Ng Teng Fong General Hospital.
Hydrogen sulphide, a toxic by-product of the water treatment process, is characterized by a pungent odor similar to rotten eggs. SCDF teams, equipped with breathing gear, used water jets to disperse the vapors, successfully clearing the site within an hour.
In response to the fatal event, the Ministry of Manpower (MOM) has initiated a thorough investigation and ordered an immediate halt to all tank cleaning activities at PUB facilities.
"Proper ventilation must be ensured to prevent toxic vapour accumulation, and workers should be equipped with gas monitoring devices and personal protective equipment, including respirator masks and breathing apparatus," an MOM spokesperson emphasized.
Additionally, PUB has instituted a safety timeout across all similar operations in confined spaces while they review and enhance safety measures.
"The safety timeout will be in effect until we are satisfied that the necessary safety measures are implemented," stated a PUB spokesperson, who also extended deepest condolences to the family of the deceased worker.
Choa Chu Kang Waterworks is considered one of Singapore’s oldest water treatment plants and is the only one in the western part of Singapore.
It is located about 500m west of Nanyang Technological University’s School of Biological Sciences, and surrounded by a forest on its southern side and the rest of the Western Catchment Area to its north and west. It was built in two phases in 1975 and 1981.
