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Workplace incident at Choa Chua Kang Waterworks – Enforcement Action to be taken against Parties allegedly responsible for Safety Lapses

Workplace safety and health

 

1            Following investigations into the workplace incident at PUB’s Choa Chu Kang Waterworks on 23 May 2024, the Ministry of Manpower (MOM) is taking enforcement action against various parties for alleged offences under the Workplace Safety and Health Act (WSHA) and its subsidiary legislation.

 

About the incident

 

2            At the time of the incident on 23 May 2024, PUB was the Occupier of Choa Chu Kang Waterworks, and Stargroup Est Pte Ltd (“Stargroup”) was the contractor engaged to carry out tank cleaning operations. As part of the cleaning operations, Stargroup had taken over the water treatment process tank, and a team of four workers from Stargroup and its subcontractor was carrying out cleaning works. Three of the workers subsequently collapsed after entering an enclosed passage beneath the tank to close hand valves that had been opened earlier to drain water from the tank. The workers were conveyed to Ng Teng Fong General Hospital where two workers passed away on 24 and 28 May 2024, and the third worker was discharged after receiving medical treatment.

 

3            MOM’s investigations found that the workers had been exposed to hydrogen sulphide gas, a toxic gas that is typically emitted when sludge is drained from water treatment tanks. Hydrogen sulphide gas is colourless and can be lethal even at low concentrations. At the time of the incident, sensors installed at the location recorded hydrogen sulphide levels that exceeded safe thresholds and the alarm had been triggered.

 

4            Following the incident, MOM issued a stop-work order to PUB to cease cleaning works on pre-treatment water tanks and entry into confined spaces adjacent to these tanks. The stop-work order was lifted on 6 August 2024 after PUB had satisfied the stipulated conditions.

 

Details of Enforcement Actions

 

5            Following MOM’s investigations, charges have been brought against the following parties on 16 July 2026:

 

  • the employer and principal of persons at work, Stargroup, had been charged for one count under Regulation 4(2) read with Regulation 8(1) of the Workplace Safety and Health (Risk Management) Regulations for failing to implement reasonably practicable measures to minimise the risk to any person who may be affected by its undertaking at the workplace; and

     

  • Lim Beng Hock, the authorised manager for confined space entry permits of Stargroup, had been charged for twelve counts under Regulation 13(3) read with Regulation 13(1) read with Regulation 24(1) of the Workplace Safety and Health (Confined Spaces) Regulations, for failing to exercise all due diligence when performing his function as authorised manager in relation to the issuance of confined space entry permits.

6            Further, MOM has taken the following enforcement actions under the WSHA and its subsidiary legislation: (a) issued a stern warning to a PUB officer for failing to cooperate with his employer to such extent as would enable his employer to comply with the WSHA the night before the incident; and (b) offered composition to PUB for allowing its employees to enter the confined spaces for short periods without adequate ventilation on previous occasions.

 

Upholding Transparency and Accountability in Workplace Safety

 

7            The WSHA requires stakeholders to take reasonably practicable measures to ensure the safety and health of persons who may be affected by work activities. Employers carrying out work in confined spaces are reminded that they are legally required to conduct a risk assessment before works commence, test the atmosphere within the confined space, provide workers with appropriate respiratory protective equipment, and ensure that a trained standby person is stationed outside the confined space at all times. Workers have the responsibility to comply with all confined space safety requirements, including using the required protective equipment and following safe work procedures. The publication issued by the WSH Council in September focusing on confined space-related incidents serves as a guide for industry stakeholders and aims to reinforce awareness of good practices for protecting workers from confined space hazards.