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WSH: Two workers passed out and died in dredge ballast tank

The Workplace Safety and Health Council of Singapore (WSH) reported in Accident Notification of 24 May 2021, that two workers had passed out and died in a dredger’s ballast tank.

What happened

A supervisor entered a dredging vessel’s ballast tank, which is a confined space, for an inspection. The supervisor entered the tank without any appropriate Personal Protective Equipment (PPE) and did not check if the confined space was safe. Shortly after entering, he collapsed and passed out.

After some time, another worker entered the tank in an attempt to rescue the supervisor, but also passed out upon entry. A third worker attempted a rescue as well, but he too collapsed inside the tank.

The rest of the crew subsequently introduced forced ventilation into the tank. The second worker eventually regained consciousness and managed to climb out of the tank. The supervisor and the third worker were later extricated by the Singapore Civil Defence Force but unfortunately did not survive.  This tragic accident highlights the invisible dangers of confined spaces. 


The WSH recommendations are as follows:

  • Do not open up any manhole into a confined space without proper authorisation;
  • Do not enter any confined space unless you have had appropriate training;
  • Do not attempt any rescue on your own without proper PPE.

Members should review:

Confined space entry: person overcome by fumes and rendered unconscious

Safety Event

Published: 22 July 2021
Download: IMCA SF 20/21

Relevant life-saving rules:
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