Carbon Monoxide Dangers

A Tragic Accident

The tragic accident last month (March 2013), involving the death of a mother and daughter on a boat on Windermere, in the English Lake District, highlights the danger of using gas in confined spaces. In this case a faulty generator is thought to be the culprit, causing carbon monoxide poisoning. Initially three people on board experienced serious breathing difficulties and were airlifted to Royal Lancaster Infirmary. Sadly two of these died. With freezing temperatures throughout the day, it was not surprising that the boaters were using a fan heater connected to the generator, but it is believed that the exhaust leaked, allowing the deadly fumes to be breathed in by the crew.

Carbon Monoxide – What Is It?

Carbon Monoxide (CO) is a colourless, odourless, tasteless gas which is highly toxic to both humans and animals when encountered in high concentrations. It is sometimes referred to as the "silent killer". In lower concentrations it is believed that the drug can have some beneficial effects, but in high concentrations and in confined spaces in particular, the gas is lethal. It is produced from the partial oxidation of compounds containing carbon and it forms when there is incomplete combustion, that is - not enough oxygen to produce carbon dioxide. This is why it is such a danger in the close confines of a boat. Many of the fatal and near fatal accidents which have been blamed on carbon monoxide poisoning result from malfunctioning or incorrectly installed fuel-burning appliances such as gas and kerosene heaters and engine-powered equipment such as portable generators. In many countries it is thought to be the most common type of fatal poisoning.

How Does Carbon Monoxide Affect Us

We all absorb very small amounts of carbon monoxide through breathing, when it enters the blood stream through gas exchange in the lungs. Normal levels in the blood are from 0% to 3%, but they can be higher in smokers. When large amounts are breathed in, however, the outcome may well be fatal as it combines with our haemoglobin to form carboxhemoglobin. This prevents oxygen being released in our tissues and reduces the oxygen-carrying capacity of the blood. The fact that the gas is so difficult to detect and is initially non-irritating, adds to its danger, as it is possible to breath it in for some time before experiencing any adverse effects.

Small amounts of the gas poisoning can produce symptoms of light-headedness, confusion, headaches, nausea, fatigue, flu-like effects and vertigo, which can develop into depression and memory loss. These symptoms can often be confused with influenza, food poisoning or gastroenteritis, but there are other signs that could point towards carbon monoxide poisoning:-

Symptoms only occur when you are in your boat.
They disappear when you are away from your boat but recur when you return.
Others on your boat (including any pets) experience similar symptoms at the same time.

Increasing exposure may produce a fast heart beat and low blood pressure. Usually with mild poisoning, removal from the source of the gas results in the patient's recovery.

Larger amounts of exposure can lead to damage of the central nervous system and heart, which may cause hallucinations, delirium, brain damage, unconsciousness and can easily result in death. At levels of around 1.28% carbon monoxide in the blood, a victim would be unconscious after 2 or 3 breaths and dead in less than 3 minutes.

One of the major causes of concern is the delayed effects that carbon monoxide poisoning can have, even up to 40 days after inhaling the gas. Older people may be more subject to this, as well as those who lost consciousness during inhalation.

Signs Of Carbon Monoxide Leaks

Flames on a cooker are a lazy yellow or orange instead of the normal crisp blue colour.
There is dark staining on or around appliances.
Pilot lights frequently blow out. (Maybe a difficult one on a boat)
Increased amounts of condensation inside windows.

What Should You Do If You Suspect CO Poisoning

Get fresh air immediately.
Turn off gas appliances.
Leave the boat if possible.
Seek advice immediately from a doctor or at a hospital.
Get your appliances checked before using them again.

Treatment can involve administering oxygen which helps to remove the carbon monoxide from the haemoglobin and restores the body's normal level of oxygen.

How To Prevent It

Carbon Monoxide poisoning can be prevented by installing a CO alarm. This looks similar to a smoke alarm and is easy to fit using manufacturer's instructions. Be aware, however, that an ordinary smoke alarm will not detect Carbon Monoxide. Choose an audible alarm, as you are particularly at risk while sleeping and you need one that will wake you up if there is danger. Make sure that the alarm you chose meets current standards and is suitable for use on a boat. Buy one that has a long-term warranty and that can be self-tested ensure correct functioning. Although CO alarms are usually inexpensive, do not select one solely based on cost, but look at the features each one offers. Be prepared to do some research, looking at recent articles and consumer reports before you make your choice.

Remember that an alarm is no substitute for having your appliances regularly checked by a qualified engineer.

Particular Danger Zones On A Boat

There are areas on a boat where dangerous amount of carbon monoxide gas can build up in minutes:-

CO gas from exhaust pipes of inboard and outboard engines and generators can build up inside and outside the boat near these pipes. Do not swim near these exhaust pipes and wait for at least 15 minutes even after the motor has been turned off.
Blocked exhaust outlets can cause CO gas to accumulate in the cabin and cockpit areas even when windows and hatches are closed.
Exhaust fumes from a vessel moored along side you with its generator or motor running could emit CO gas into your cockpit or cabin. Try to moor up at least 20ft away from a boat running its motor.
Travelling at low speed, idling in the water and a tailwind can cause CO gas to accumulate almost anywhere, even in open areas.
Back drafting can cause CO build up when a boat is operated at a high bow angle, is heavily loaded or has an opening that draws in exhaust fumes.
Altering the configuration of your boat can change the airflow and the ability of the boat to purge itself of CO gas, so adding something as insignificant as a canvas dodger, to provide more comfort for your passengers, may actually put them in danger. A good flow of air around the boat, while requiring an extra layer of clothing, might be a safer option.

Use A Checklist Each Trip

Make sure all passengers understand the dangers of CO poisoning.
Check that all exhaust clamps are secure.
Look for any signs of leaking gas such as rust and black streaks, water leaks, or cracked or corroded fittings.
Inspect exhaust hoses ensuring they are free of kinks or burned and cracked sections.
When the engine and generator are started confirm that water is flowing from the exhaust outlet.
Listen for any changes in sound that might indicate a faulty exhaust component.
Test the CO detector by using the test button and make sure the battery is in good condition. Do Not take the battery out unless you are replacing it.

Annual Checklist

(To be performed by a qualified marine technician)

Replace worn or cracked hoses.
Inspect water pump housing and impeller for wear and make sure cooling systems are working correctly.
Check metallic exhaust components for cracks, leaks, rust or loosening.

And Finally

Boats are built to keep the water out, but at the same time, this makes them idea containers for gasses and fumes. Be aware of the dangers and don't let a preventable accident spoil your boating.

Author – Dee White