• Published: 26 May 2011
  • Incident ID: 3164

High potential confined space incident

Cause & Consequence

  • Other
Incident Consequence

Incident Location

Any Location Type

Incident Activity


Incident Info Source

Specific Incident Equipment

Ballast tank, tank entry hatch, confined space entry

Lessons Identified

Subsequent gas sampling during the investigation into the incident recorded unexpectedly high levels of hydrogen within the tank, the presence of which is probably due to the electrolytic reaction between the sacrificial anodes in the tank and the steel within the ballast tank.

Incident Recommendations

This alert has been issued to heighten awareness of the potential for this unusual situation to arise. While one would normally expect heavier than air gasses or lack of oxygen due to scavenging in these spaces One must always be aware of the potential presence of other gases at all times. Due to the unusual nature of the gases involved it is recommended that risk assessment of the proposed task should always include the potential for this lighter than air gas with suitable risk reduction being put in place.Further information and recommendations will be posted when investigations into this incident have been completed

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