Incinerators – Too hot too handle?

CHIRP has received reports from a ship manager relating to serious incidents involving  incinerators

Report 1:

An engineer was carrying out incineration of garbage assisted by an oiler. After loading several bags containing either rags or filters into the incinerator, one of the bags containing a filter jammed. The interlock that should have prevented the engineer from opening the external door failed, he opened the external door of the loading chamber and attempted to use a stick to free the filter. When this was not successful he then attempted to push the filter with his hand. The filter became free causing the sluice door to close suddenly, trapping the hand until another engineer freed him a few minutes later. The engineer sustained 3rd degree burns and subsequently had to have an amputation of his fingers and thumb on the right  hand.

Investigation into the incident revealed, direct causes:

• Unsafe Condition: Interlock failed allowing the exter- nal door of the feed chamber to
• Unsafe Act: The 4th Engineer opened the external door and put his arm into the incinerator instead of stepping
• The oiler did not intervene in this

Root causes:

• The safety device (interlock) was inoperative after a modification had been carried out on the
• Ships staff were unaware that a contractor had made the
• The sluice door did not fully open when an impulse was given on the sluice door
• The Engine Information Book had four documents related to the operation of the incinerator, which gave conflicting
• The burning of garbage was not on the daily work Garbage had been previously burnt on board without being on the daily work plan. No Risk assess- ment was used on this  occasion.

Report 2:

While operating the incinerator, a bag of oil soaked sawdust was put into the loading chamber and within seconds a fireball was ejected from the chamber causing second-degree burns to the  operator.

Investigation into the incident revealed, direct  causes:

• Modifications to the incinerator were not documented correctly (internal refractory wall had been removed).
• Incinerator was not being operated as designed and did not allow the combustion chamber to reach its optimum temperature of 850ºC before loading garbage. It had become common practice onboard to run the incinera- tor at much lower temperatures; there was evidence of incomplete combustion. Debris was evident in the sluice door hinges; this prevented full closing of the sluice
• The quantity of sawdust in each bag was not strictly controlled; the manufacturer’s instructions state a maximum of 12 litres to be loaded however 14–16 litres of sawdust was removed from the incinerator after the
• Correct requirements for PPE should have been re- viewed prior to the commencement of the task. The provision for a full-face visor and flash hood/neck protection is now mandatory for persons involved in or observing incinerator operations
• Failure of the door interlocks allowed the loading door to be open even though the sluice door wasn’t fully closed. The limit switch on the sluice door was not operational; this went
• Inner sluice door was not properly maintained, this contributed to the door not being fully closed during operation.
• There was an inherent lack of comprehensive and effective training onboard pertaining to the correct and safe operation of the
• A comprehensive toolbox talk never took place prior to incineration

The ship managers also advised that over a period of 6 years their fleet received 61 non-conformances reports with 15 having the potential to cause injury or   damage.

The main causal factors were the failure to follow rules, failure to secure the unit before use, improper handling of waste, inadequate preparation/planning and equipment failure.

A deeper look for the root causes identified error enforcing conditions, hardware and inadequate hardware design/ construction/installation  and  inadequate procedures.