Carbon monoxide poisoning is sometimes called death by stealth and there have been some high profile marine cases that have made unpleasant media headlines in recent times. Victims are unaware that they are being poisoned and the symptoms are hard to spot. In this specially commissioned feature, Susan Stockwell, Director of Nereus Alarms Ltd, discusses how CO is produced and offers readers some background to this hidden killer. She also gives essential advice that surveyors will surely find invaluable.
Carbon monoxide poisoning is caused by starving the body of oxygen. It displaces oxygen in the blood when the red blood cells bind with it in preference to oxygen. Consequently, the body cannot function as multiple organ failure occurs.
The symptoms of carbon monoxide poisoning
Symptoms of low level carbon monoxide poisoning can include headaches, nausea, stomach pains, tiredness, dizziness and confusion. Understandably this makes it very difficult to diagnose as the symptoms can be confused with so many other conditions. More so because no symptoms may be present at all. Low level symptoms can become progressively worse over time, or can subside when away from the source. High level poisoning can occur very quickly and rapidly leads to unconsciousness and death. Death can be almost instantaneous from first exposure. Older people, children and domestic animals are at higher risk of this poisoning because of their smaller body masses. Thus, on craft used by people bringing animals aboard, or used, or crewed by people from either of these groups, care taken should be increased proportionately. Similarly, if the boat is used for drinking alcohol then the likelihood of people being more careless of safety should be taken into consideration. On a chartered vessel then the temporary users have to relied on to read, understand and follow all instructions as to operating equipment properly. A child, someone who doesn’t read or understand the English language, or even just someone bloody minded who doesn’t believe in health and safety is at high risk of simply not following instructions. And what is fondly referred to as “canal disease” i.e. being drunk, is not confined to users of those particular vessels.
Carbon monoxide is generated by incomplete combustion of a carbon based substance. This might be gas (LPG), petrol, diesel, oil, wood, charcoal, solid fuel (coal or coke), kerosene/paraffin or methylated spirits. During complete combustion carbon and oxygen combine to create carbon dioxide. During incomplete combustion they combine to create carbon monoxide. This occurs when the carbon based product being burnt, or combusted, is not provided with enough oxygen to generate only carbon dioxide and monoxide is created instead. On a vessel, if a living creature, whether a mouse or a human stowaway, comes to the end of their days in the ventilation system then the burning taking place on board may be starved of oxygen and so carbon monoxide may generated at anything up to fatal levels. The same affect will of course be created by sleeping or hiding in the ventilation of a vessel.
One traditional way of spotting that incomplete combustion is occurring is by looking for sooting near where the combustion is taking place. As a classic car enthusiast was recalling to the writer recently, if the engine is running too rich you can tell because the spark plugs will be sooted up. Too much petrol being squirted in apparently means not enough oxygen in the mix, so that it won’t burn properly and soot is generated. Just one apparently of the many obstacles to be overcome on the highly satisfying route to a smoothly running TR2. Sooting indicates incomplete combustion, which in turn means that Carbon Monoxide has been generated. In checking for this the following mainstay of crime fiction beloved of the female reader should be borne in mind. If the area where you would expect to have seen sooting is much cleaner than might have been suspected eg that room, or part of it, seems to have been cleaned more recently that elsewhere, then suspicions should be aroused.
Carbon monoxide poisoning afloat
Carbon monoxide poisoning afloat can be created in many ways. The first set of circumstances are those in which carbon monoxide is expected to be a bi product. Smoking a cigarette, cooking on a barbecue with charcoal, smoking a shisha pipe, or running an engine on petrol or diesel will all be expected to generate CO. The danger from these forms of burning has been well known from ancient times to the present. In ancient Greece shutting someone in a room with slow burning coals was used to kill through poisoning of the air. The use of carbon monoxide in car exhausts for suicide is also well known.
On a small vessel such as a pleasure craft simply banning the use of barbecues, hookah pipes and even smoking will stop CO from these sources. However, it is only as effective as the ban’s enforcement. On a charter vessel the risk of users ignoring safety instructions is high. Drinking alcohol and thinking health and safety requirements are some sort of conspiracy are quite common in our culture and this should be taken into account in deciding the level of warning given. Therefore it is suggested that all users of a vessel, whether the person paying for hire or their guests, signs for reading these warning regarding what is banned as well as any other safety measures. Whatever they read needs to be in large enough print to be legible and ideally signed on every page and copy provided. The use of sticker icons warning against whatever is banned whether smoking, or charcoal may reduce the risk of the ban being ignored.
On a larger vessel prone to stowaways, or use as sleeping accommodation in areas not designed for such, enforcing a ban is similarly difficult. People fleeing countries where their families and friends have been killed and their property, including land, taken from them by the authorities, will not be reading health and safety briefings when stowing away or using rented space to sleep in dangerous areas of a ship. However, just as the owner of property has a legal duty regarding the safety of burglars (man traps have been illegal for many years) so a ship owner should be mindful of the safety of everyone on the vessel. Death or illness through carbon monoxide poisoning is a real hazard for people confined to very small spaces without heating who will light fires to keep warm. This should be taken into account in devising procedures generally for ongoing checks for stowaways aboard. Areas which could be used for this purpose need to be checked on an ongoing basis.
Banning of petrol and diesel engines on land is certainly being mooted in various countries, particularly for cities. Banning of diesel engines at least is also reported on some waterways. Perceived problems from noise and pollution from exhaust fumes of pleasure craft in marinas, particularly inland, has led to pressure to ban use of diesel and certainly to prevent the building of more moorings. The increased demand for the luxuries provided by electricity including technology means that diesel generators and engines can be running almost continuously during mooring. The next approach to situations which, in ordinary use, are guaranteed to produce CO is ventilation. This is in fact two fold. There is ventilation to minimise the production of CO by maximising the amount of air and therefore oxygen which reaches the point of combustion. There is also ventilation which takes away the exhaust fumes which contain CO. Installation of the ventilation system needs to be carried out professionally, so that the design of the vessel and the fitting of anything which carries away exhaust fumes should be effective. Maintenance and correct operation are also essentials. Corrosion and poor jointing is a risk on large and small vessels as is the possibility of the exhaust system becoming blocked. The smallest of leaks from the exhaust will allow fumes to escape into what are generally very small well sealed areas on ships and boats. The fact that ships even need a set of regulations covering confined spaces shows the potential for accidents in these areas. Fumes associated with freight as well as the ever present risk of carbon monoxide escapes have caused enough accidents for these regulations to be put in place. On a boat the cabin area is a classic place for fumes to be able to build up. In fact, some manufacturers consider carbon monoxide detection in all cabins. Blockages of exhaust ventilation is a potential problem where vermin nest or die in the area whilst a boat is laid up. Similarly, ventilation can become blocked by vegetation caught up in it. Simply mooring inappropriately hard up against something which bocks the exhaust can be a problem. Blow back in high winds is another risk for vessels of all sizes. Poor maintenance and in particular failure to service solid fuel burners and gas fires for cooking can starve the appliance of air needed for safe combustion.
Fuel such as LPG which would normally burn without generating CO or with relatively low levels will start to generate dangerous levels when starved of oxygen by blocked ventilation. The colour of a gas flame burning healthily, with enough oxygen, is expected to be blue. Without enough oxygen and smouldering it is likely to be orange. Users of small craft, particularly those not used to spending time afloat, have a tendency to block off ventilation in order to try to keep warm, particularly in the winter months. Sealing up any drafts around windows and blocking off deliberately installed ventilation points is likely to occur where passengers and crew are not aware of the risks run in doing so. In the same way that vermin and birds’ nests will block chimneys and pipes on land and in smaller craft, larger craft can also run the risk of blockages in ventilation.
Carbon monoxide poisoning incidents occur both on land and afloat.
Ralph Waldo Emerson, sometime leader of the transcendentalist movement in America, said “Build a better mousetrap and the world will beat a path to your door”.
Mice are still a problem today and so is carbon monoxide. Unlike mice, which we can see hear and smell, human beings cannot see, hear or smell carbon monoxide.
Relying on the medical profession for warnings and diagnoses of this poison is a bit hit and miss. Awareness has risen in France following the death of a doctor called to a carbon monoxide poisoning case. The doctor himself died as he, like the rest of us, had no means of detecting the presence of the gas through his own bodily senses. The French are now reported in our press as recording 100 cases a year of death from carbon monoxide poisoning. However, in this country routine post mortem testing for this form of poisoning doesn’t take place despite that fact that so many deaths occur in places where carbon based fuel is burnt for heating or cooking. The brighter blood colour does not always occur in carbon monoxide poisoning cases and unless the skin is broken, spotting it on a body whose skin colour is dark would obviously be more difficult than someone with fairer skin.
It is now possible to monitor carbon monoxide levels in the body much more easily. This is apparent in recent reports of a former smoker in this country who was being monitored for carbon monoxide in his body. It was assumed he had failed to give up when his levels didn’t respond by dropping as expected. As an ex smoker his poisoning as a result of a bird nest in the ventilation blocking air to a boiler was only picked up because his blood tests showed high levels of carbon monoxide. This is a recognised risk for carbon monoxide and just one example of a large bird’s nest creating conditions which generated this poison in someone’s home.
A conviction for manslaughter was made in the case of the Arniston, when a Gas Safe fitter who brought a petrol generator on board a boat on which he himself had bodged the exhaust system. As a result two deaths occurred on board, one that of a child. He himself awoke with the classic symptoms of the poisoning which he believed to be heart problems. This was a recent case that received national press coverage and took place on Lake Windermere.
Still under investigation at the time of writing is the case of a couple in their 50’s and 60’s as well as a dog who all died in mid 2016 at Wroxham Island on the Norfolk Broads. Their engine had been left running whilst moored, probably to charge batteries. The exhaust fumes had blown in under the canopy over the boat. On testing by the Marine Accident Investigation Board the levels reached dangerous levels within 3 minutes. The reminder not to ignore the smell of exhaust fumes echoes childhood warnings remembered by the writer of this article to avoid sitting at the back of buses near the engine where the smell of fumes could be pretty awful.
Eschol is the name of a scallop dredger which was used as overnight accommodation by two people who died from carbon monoxide poisoning. In this case the fumes from a butane grill clearly lit for keeping warm had killed them. It was still burning when they were found dead in their bunks. Readers may recall student accommodation officers’ warnings not to use cookers for heating in student digs on the same principle. Something which may be safe for burning for the relatively short period whilst being used for cooking may not be so for hour upon hour of burning without good enough ventilation for heating.
The Marine Accident Investigations Branch carries various other reports of accidents involving this form of poisoning which can be found by using the search facility on their section of the .gov website.
Writer’s credentials and first-hand experience of CO poisoning
The writer of this article is able to draw on basic chemistry learnt at school, incidents of carbon monoxide poisoning in both her workplace and her own home, experience acting for a victim of carbon monoxide poisoning, 15 years marketing marine gas detectors and a soupcon of help from Wikipedia.
The carbon monoxide incident in a former workplace had resulted in several casualty admissions for a colleague who as young girl was assumed to just be prone to fainting. Fortunately, I noticed that the room she worked in was probably poorly ventilated after a conversion of the building and that the gas fire was right next to her desk. Only after being asked to test for carbon monoxide presence was it discovered and the standard treatment of the use of a decompression chamber was used.
The incident in the writer’s own home occurred some years, ok decades, ago in student digs. A gas cooker had been poorly maintained so that soot was visible around the pilot light. On discussing this earlier student event with the medical expert when representing a carbon monoxide poisoning victim, he, the expert, asked how I was after having lived with carbon monoxide in the house. Fortunately, I myself had been sleeping in the room furthest from the faulty appliance, a cooker with a sooted up pilot light. He asked after the other occupants, whether they had done as well as expected in their degrees. Certainly the girl directly over the kitchen had not. The girls in the other rooms hadn’t shone but the one directly above the carbon monoxide and sleeping there with low level poisoning for several weeks had, as the expert expected, had a far worse set of results than expected. The expert suspected that the low level poisoning would have caused brain damage.
The girl suspected of poisoning was in fact a very small slight person which again would put her at higher risk of poisoning. As mentioned above, children and older people as well as domestic animals, are considered more vulnerable to poisoning because they have a smaller body mass.
Even as a small child I came across the risk of carbon monoxide. My grandparents would bank up the fire just before going to bed and close off the floor draft to the fire so that the ashes would keep hot rather than put the fire out. Essentially the fire was left to smoulder as slowly as possible by depriving it of air. Banking up would mean pulling the ashes over what was still burning. Something slow burning isn’t getting enough oxygen to burn safely and will generate deadly carbon monoxide in preference to carbon dioxide. I can recall the arguments as my mother remonstrated with her in laws over this. This form of smouldering fire is very similar to the burning of a cigarette, in which the tobacco is packed so tightly that little air can get to the strands of leaf. In fact fifteen years ago Googling carbon monoxide would have just brought up a lot of French websites referring in French to carbon monoxide in cigarettes.
These incidents are mentioned to emphasise the fact that increased awareness is likely to lead to much higher records as people realise what has been creating symptoms so easily confused with infections like flu, heart disease and just feeling “off colour”. As the oxygen starvation affects the entire body the effects can be felt almost anywhere.
To summarise, carbon monoxide can emanate from many different sources or many different forms of craft, large and small, commercial and non-commercial, maritime and inland. All have potential for rapid build-up of any gas in confined spaces. Detectors for carbon monoxide for use in marine applications may, depending on the type of craft, need to withstand humidity, temperature changes and motion. It is respectfully suggested that surveyors will be able to assist users of craft in whether carbon monoxide detectors should be fitted based on the risks outlined in this article. Similarly the particular features required of the detectors should be apparent from the expected conditions aboard. Most situations afloat will expose a detector to motion, temperature extremes and humidity for which the design of a domestic alarm is unlikely to have made provision.