99042 Fatality Caused By Fumes from Cargo
Fatality Caused By Fumes from Cargo
Report No. 99042
A few years ago, a Surveyor, whose seagoing career had been spent on tankers, was assigned to do an out-turn survey which included sampling the soy bean cargo. No problems were experienced as most of the hatches were open, however, the last hold to be sampled was still closed, possibly due to a small technical fault. Rather than wait for the repairs to be completed, like all good surveyors he was keen to finish the sampling and get on with the deadweight calculation, he entered the hold with one of the officers down the access ladder.
When they did not return after some minutes, the alarm was given. The Master was informed and, being more careful, he instructed the crew to open the hatch. They saw the men laying face down under the box beams. They were both dead before expert help arrived on the scene. It would appear that CO2 gas was present, this is colourless and odourless and is common in foodstuffs such as grain.
A lesson was learnt by all. Most of us brought a gas detection/oxygen depletion monitoring instrument and made sure we used it. It was also a lesson for tankermen who think that nothing much of importance or dangerous happens on a dry cargo ship.
Such portable monitoring equipment was common on board all tankers but not usually found on bulk carriers or other vessels unless it had been specially provided for particular cargoes. All ships should be fitted with gas sampling apparatus for entry into enclosed spaces, it should be remembered that this includes cargo spaces where fumes may be present.
Officers and crew should get to know various smells and colours of dangerous gases and fumes. Not all gases have any smell or colour, CO2 as has already been mentioned and carbon monoxide are included in these. Hydrogen given off by coal cargoes is also odourless and is very flammable.
For quick reference here are a few that come to mind:
- Chlorine gas is greenish/yellow in colour
- Fluorine is pale yellow
- Hydrogen Sulphide smells like rotten eggs
- Phosphene smells like rotting fish
It must be remembered that many strong smelling gases can damage the olfactory nerves after short term exposure. If this happens, further detection or an increase in the intensity is not noticed, thus a person becomes unaware of the danger, possibly with dire consequences.
Dangerous Goods Warning
Long experience has shown that extreme care has to be taken by non-chemists handling chemical names, in some cases a one letter wrong in the name can completely alter what a substance is or does. It is also very easy in an emergency to locate a substance in an index that is nearly right, but if slightly different is definitely not the right substance, writes Capt. Graham Evans, the well respected DG expert.
The MARS co-ordinator has been found guilty of this very offence, for which I offer my sincere apologies.
Dr J Cowley has been pointed that I spelt "fluorine" as "flourine" in MARS 99042. He also says;
"Phosphene smells like rotting fish" should probably be - "phosphine smells like garlic" or perhaps "phosgen has a foul odour" (This can be described as an unpleasant choking odour" some say like rotting fish but at low levels it just smells like hay).
Capt. Evans goes on to say. "On the whole this well-intentioned article was a good one illustrating the type of incident that kills hundreds of seamen and dock workers every year around the world, including the odd surveyor. The author of MARS 99042 says to use gas detection and monitoring equipment and that some dangerous gases have no colour or smell. Too many good seamen have been lost relying on their nose for safety.
The bit that rang warning bells in my mind was where he suggests that officers and crew should get to know the colours and smells of dangerous gases. This brings to mind the picture of an enthusiastic junior officer deliberately sniffing different gases or vapours. What is meant of course is to have this information to hand as reference material in case of accidents. Whether you will be able to smell it before it is doing you harm depends on the relationship between the odour threshold and the occupation exposure standard. As pointed out by the author, some gases (such as hydrogen sulphide) anaesthetise your sense of smell at the levels where they begin to do you harm.
We once had a phosphine poisoning incident and there was no reported smell, just symptoms afterwards. The poisons centre diagnosed phosphine gas poisoning from a description of the symptoms. In the ASIA FREIGHTER incident, the London poisons centre diagnosed arsine gas poisoning from a description of the symptoms which later turned out to be correct."