Investigation into Worker Death and Injury during Tank Cleaning at PUB’s Choa Chu Kang Waterworks Plant
Ministry of Sustainability and the EnvironmentSpeakers
Summary
This question concerns the investigation into a fatal gas leak at PUB's Choa Chu Kang Waterworks, where Ms Poh Li San and Mr Melvin Yong Yik Chye asked about the cause, worker conditions, and safety measures. Minister for Sustainability and the Environment Grace Fu Hai Yien reported that two workers died and one was discharged following inhalation of hydrogen sulphide emitted during routine tank cleaning. Initial findings revealed hydrogen sulphide levels were higher than normal while draining sludge, leading to an ongoing investigation by the Ministry of Manpower. In response, PUB implemented a board-wide safety time-out to review procedures for confined spaces and toxic gas risks across all its facilities. While work has since resumed at other sites after safety audits, a Stop Work Order remains in place at the affected plant during the investigation.
Transcript
46 Ms Poh Li San asked the Minister for Sustainability and the Environment (a) what are the initial findings from investigations into the incident resulting in the death of a worker and injuries sustained by two others during routine tank cleaning at PUB’s Choa Chu Kang Waterworks; (b) what is the cause of the hydrogen sulphide gas leak; (c) whether an update can be provided on the condition of the two workers under intensive care; and (d) what are the lessons learnt to ensure such mishaps do not repeat.
47 Mr Melvin Yong Yik Chye asked the Minister for Sustainability and the Environment with regard to the incident at PUB’s Choa Chu Kang Waterworks where two workers inhaled toxic gas when carrying out tank cleaning works, what safety measures are in place at all PUB waterworks to ensure the safety of workers against the risk of exposure to toxic gases and chemicals.
Ms Grace Fu Hai Yien: First, I would like to express my deepest condolences to the families and loved ones of Mr Srinivasan Sivamaran and Mr Izzat Naqiuddin Bin Dawood, who lost their lives due to the incident at PUB’s Choa Chu Kang Waterworks on 23 May 2024. The third worker, Mr Erifin Anak Awan, was discharged from hospital on 22 June 2024. I wish him a swift and full recovery.
I seek Members’ understanding that I can only provide basic information due to the ongoing investigation by the Ministry of Manpower (MOM).
On 23 May 2024, during routine cleaning of a water treatment process tank at Choa Chu Kang Waterworks, three contractor workers were found to have collapsed. Initial investigations indicated that they had inhaled hydrogen sulphide. Hydrogen sulphide is a gas that is typically emitted when sludge is being drained from the tank. At the time and location of the incident, hydrogen sulphide levels were higher than normal based on the hydrogen sulphide sensors installed.
As a precaution immediately after the incident, the Public Utilities Board (PUB) issued a Board-wide safety time-out. During the time-out, PUB carried out comprehensive checks on its processes and safety procedures, both at Choa Chu Kang Waterworks and across PUB. Checks were specifically made in the management of work in confined spaces and locations where there was risk of exposure to toxic gases and chemicals. Work resumed across PUB after ascertaining that safety procedures were adequate and in place, with the exception of Choa Chu Kang Waterworks where MOM’s Stop Work Order is still in force.