Suspected case of Legionella onboard vessel
- Safety Flash
- Published on 18 December 2018
- Generated on 7 July 2025
- IMCA SF 28/18
- 2 minute read
Two cases of “acute pneumonia in severe form” were identified on a survey vessel with 42 persons onboard, including crew and client’s representatives.
What happened?
The client’s health team assumed it to be a case of Legionella. The vessel went into port and both affected personnel were evacuated and sent to a medical clinic for examination.
What were the causes?
Legionella infection is caused when bacteria gains entry into the respiratory system. This can occur from water suspended in air in the form of a fine mist as created by showers or tap sprays.
Well maintained water tanks, pipe work, pumps and hoses, along with good water management practices can help control the legionella bacteria.
Corrective Actions
- Legionella and throat culture tests were arranged for all personnel onboard.
- Swab tests were taken from the ventilation systems in the cabins of the two affected personnel.
- Deep cleaning of all vessel cabins and washing and cleaning of all ventilation air grates (as well as pipes).
- Appropriate cleaning chemicals were passed through the ventilation system by a specialized contractor so that air flow could assist in the disinfection process. Treatment of portable water tanks was arranged also.
- Arranged appropriate cleaning/chlorination of cabin shower heads at quarterly intervals.
Medical test reports later confirmed that:
- The two persons were not infected with Legionella. They were diagnosed with acute respiratory infection and appropriate medicines prescribed.
- There were no signs of Legionella disease confirmed onboard.
Members may wish to review:
- Guidance on occupational health (IMCA HSS033)
Related Safety Flashes
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IMCA SF 31/17
15 December 2017
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IMCA SF 05/04
1 June 2004
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