1. The atomiser unit’s air nozzle holes were found to be choked with hard viscous sludge thereby restricting the flow of air into the incineration chamber. This condition seemed to have existed for some weeks prior to the incident;
2. Waste oil had failed to atomise properly and had collected and spread over the bottom of the combustion chamber and ignited, producing a large quantity of smoke;
3. The smoke activated the fire alarm, triggering the local fixed water mist fire extinguishing system.
Root cause/contributory factors
1. Failure to maintain the incinerator’s burner assembly as per maker’s recommendations; in particular the atomiser nozzles had not been properly inspected and cleaned;
2. Failure to fully inspect the combustion chamber, which would have shown that waste oil had accumulated on the bottom from previous burning operations;
3. Failure to properly monitor the exhaust during past operations which would have indicated abnormal combustion.
Engineers’ familiarisation form revised to include training and familiarisation in the use of the incinerator. A new fleet circular was issued to all vessels, instructing all engineers to:
1. Discuss the incident at their next safety meeting;
2. Conduct onboard training on proper operation and maintenance of the incinerator, including emergency stop procedures, checks to be carried out prior to and during the use of the incinerator;
3. Ensure that the incinerator is cleaned and checked after every use;
4. Regularly test all safety devices on the incinerator as well as emergency stops.
Source: Mars,The Nautical Institute