Safety Lessons from Marine Incident Investigation (Company Report) – No.3 – January 2022
The owner and their son were seriously injured in an explosion in the galley of their houseboat due to the stove ignitor setting off a gas leak. An AMSA investigation report found that the incorrect disconnection of appliances from the fixed gas LPG system was the most likely source of the gas leak.
At about 1950 on 30 June 2021, a class 4E domestic commercial vessel houseboat used for recreational purposes was at anchor in the back channel of a Northern NSW river. The owner and their son were onboard and the owner was preparing dinner in the galley at the starboard aft end of the main cabin. The owner attempted to light a gas-powered stove by a piezo ignition switch when a blast explosion occurred causing catastrophic damage to the vessel structure and fittings.
The owner and their son self-rescued and administered first aid while waiting for assistance from emergency services. Ambulance paramedics transported the two individuals to hospital for treatment. The owner was later transferred to a burns unit to receive specialist treatment having received burns to 25% of their body.
The investigation identified the following contributory factors:
- As part of the investigation, a licensed gasfitter plumber inspected the fixed gas system onboard and found it to be not in compliance with the requirements of Gas Supply (Consumer Safety) Regulation 2012, due to:
- Gas appliances as indicated on the compliance plate were not installed.
- Where a gas appliance was not fitted, the connection point was not sufficiently capped to prevent a gas leak.
- A gas detector was not observed on the vessel.
- Propane gas was most likely the cause of a flammable gas air mixture within the vessel
- A faulty gas isolation valve leaking through an open outlet within the kitchen cabinetry was likely the source of uncontrolled gas escape.
- The source of ignition was the piezo ignition switch on the gas cooktop/stove operated by the owner in the moment before the explosion.
Domestic commercial vessel owners with vessels housing fixed gas LPG systems onboard must have knowledge of, and visually check, the appliances listed on the installation compliance plate. Where appliances have been disconnected from the system, re-certification by a licensed gasfitter is required.
The investigation uncovered partial evidence that an LPG cylinder was being stowed inside the cabin of the vessel and the potential contribution of this to the uncontrolled build-up of propane gas could not be ruled out. Owners are reminded to carefully consider the risks associated with the stowage location of LPG cylinders.