USCG Marine Safety Alert

The Coast Guard's investigation revealed that two crewmembers were conducting hot work in a known hazardous zone on the air castle deck of a tri-fueled vessel (LNG, diesel, battery). Unaware that the vessel was currently using LNG as its fuel source, the crew initiated hot work in an area they would have otherwise avoided had they known about the active fuel source being used at the time. Compounding this risk, the actuator for the engines’ purge valve malfunctioned, causing methane vapors to vent into the hot work area. Mistaking the area as being gas-free, the crewmembers struck a lighter, igniting the methane and resulting in severe burns and a fire onboard.

https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/USCGSA_0525.pdf