USCG issues safety alert on hazardous zone marking and awareness

The United States Coast Guard issued Safety Alert 04-25 regarding a recent incident involving a tri-fueled vessel (powered by liquefied natural gas (LNG), diesel, and batteries) highlighting the critical dangers of working in hazardous zones without proper precautions. This incident resulted in a fire and severe injuries to crewmembers, underscoring the need for clear hazard identification and strict adherence to safety protocols.

In this case, the crew was performing maintenance work on top of the pilothouse, near crankcase and LNG purge vents. Although they were aware of the vents, they were unaware that the vessel was actively using methane as a fuel source. This lack of knowledge led them to believe that the area was gas-free. However, the space was classified as a hazardous zone in the vessel’s plans, even though it was not physically or visually marked as such on the deck.

While work was underway, a failed engine purge valve actuator released LNG vapors into the area. Unaware of the potential risk, a crewmember struck a lighter, igniting the vapors. The resulting fire caused severe injuries to both crewmembers in the vicinity.

This incident demonstrates the importance of ensuring that hazardous zones are clearly identified and that crews are made fully aware of their risks. Proper hazard awareness, visible markings, and adherence to safety protocols are essential to prevent such accidents.

Recommendations:
To prevent similar incidents, the Coast Guard strongly encourages vessel owners, operators, and other stakeholders to take the following actions:

Review hazardous zone requirements and ensure crewmembers fully understand the conditions and risks that define these areas.
Clearly mark all hazardous zones on vessels and ensure that crews are aware of their locations and the associated dangers.

Marine inspectors, investigators, and surveyors are urged to remain vigilant about these issues and take corrective action where necessary.

This safety alert is informational and does not replace any existing safety, operational, or material requirements. It was developed by Marine Safety Unit Houma and distributed by the Office of Investigations and Casualty Analysis. For questions, contact HQS-SMB-CG-INV@uscg.mil.