What are the Dangers of Carbon Monoxide? 

Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood, and coal. It is only when fuel does not burn fully that excess CO is produced, which is poisonous. When CO enters the body, it stops the blood from bringing oxygen to cells, tissues, and organs. CO is poisonous as you cannot see it, taste it, or smell it but CO can kill quickly without warning.  

Regulation  

The Health and Safety Executive (HSE) prohibit worker exposure to more than 20ppm (parts per million) during an 8-hour long term exposure period and 100ppm (parts per million) during a 15 minute short term exposure period. 

OSHA standards prohibit worker exposure to more than 50 parts of CO gas per million parts of air averaged during an 8-hour time period. The 8-hour PEL for CO in maritime operations is also 50 ppm. Maritime workers, however, must be removed from exposure if the CO concentration in the atmosphere exceeds 100 ppm. The peak CO level for employees engaged in roll-on roll-off operations during cargo loading and unloading) is 200 ppm. 

What are the dangers? 

CO volume (parts per million (ppm) Physical Effects

200 ppm Headache in 2–3 hours  

400 ppm Headache and nausea in 1–2 hours, life threatening within 3 hours.  

800 ppm Can cause seizures, severe headaches and vomiting in under an hour, unconsciousness within 2 hours.  

1,500 ppm Can cause dizziness, nausea, and unconsciousness in under 20 minutes; death within 1 hour  

6,400 ppm Can cause unconsciousness after two to three breaths: death within 15 minutes 

Around 10 to 15% of people who obtain serve CO poisoning go on to develop long-term complications. These include brain damage, vision and hearing loss, Parkinson’s disease, and coronary heart disease.   

What are the health implications? 

Due to the characteristics of CO being so hard to identify, i.e., colourless, odourless, tasteless, poisonous gas, it may take time for you to realise that you have CO poisoning. The effects of CO can be dangerous.  

Implication to Health  Physical Effects 
Oxygen Deprivation  CO prevents the blood system from effectively carrying oxygen around the body, specifically to vital organs such as the heart and brain. High doses of CO, therefore, can cause death from asphyxiation or lack of oxygen to the brain.  
Central Nervous system and Heart Problems  As CO prevents the brain from receiving sufficient levels of oxygen it has a knock-on effect with the heart, brain, and central nervous system. Symptoms including headaches, nausea, fatigue, memory loss and disorientation.  

Increased levels of CO in the body go on to cause lack of balance, heart problems, comas, convulsions and even death. Some of those who are affected may experience rapid and irregular heartbeats, low blood pressure and arrhythmias of the heart. Cerebral edemas caused because of CO poisoning are especially threatening, this is because they can result in the brain cells being crushed, thereby affecting the whole nervous system. 

Respiratory System  As the body struggles to distribute air around the body as a result of carbon monoxide due to the deprivation of blood cells of oxygen. Some patients will experience a shortness of breath, especially when undertaking strenuous activities.  

Every-day physical and sporting activities will take more effort and leave you feeling more exhausted than usual. These effects can worsen over time as your body’s power to obtain oxygen becomes increasingly compromised.  

Over time, both your heart and lungs are put under pressure as the levels of carbon monoxide increase in the body tissues. As a result, your heart will try harder to pump what it wrongly perceives to be oxygenated blood from your lungs to the rest of your body. Consequently, the airways begin to swell causing even less air to enter the lungs. With long-term exposure, the lung tissue is eventually destroyed, resulting in cardiovascular problems and lung disease. 

Chronic Exposure  Chronic exposure can have extremely serious long-term effects, depending on the extent of poisoning. In extreme cases, the section of the brain known as the hippocampus may be harmed. This part of the brain is accountable for the development of new memories and is particularly vulnerable to damage.  

Whilst those who suffer from long-term effects of carbon monoxide poisoning recover with time, there are cases in which some people suffer permanent effects. This may occur when there has been enough exposure to result in organ and brain damage.  

Unborn Babies  Since foetal haemoglobin mixes more readily with CO than adult haemoglobin, the baby’s carboxy haemoglobin levels become higher than the mothers. Babies and children whose organs are still maturing are at risk of permanent organ damage.  

Additionally, young children and infants breathe faster than adults and have a higher metabolic rate, therefore, they inhale up to twice as much air as adults, especially when sleeping, which heightens their exposure to CO. 

 How to meet compliance?

The best way to protect yourself from the hazards of CO is be wearing a high quality, portable CO gas detector. 

Clip SGD is designed for use in hazardous areas whilst offering reliable and durable fixed life span monitoring in a compact, lightweight and maintenance free device. Clip SGD has a 2-year life and is available for hydrogen sulphide (H2S), carbon monoxide (CO) or oxygen (O2). The Clip SDG personal gas detector is designed to withstand the harshest industrial working conditions and delivers industry leading alarm time, changeable alarm levels and event logging as well as user-friendly bump test and calibration solutions.  

Gasman with specialist CO sensor is a rugged, compact single gas detector, designed for use in the toughest environments. Its compact and lightweight design makes it the ideal choice for industrial gas detection. Weighing just 130g, it is extremely durable, with high impact resistance and dust/water ingress protection, loud 95 dB alarms, a vivid red/ blue visual warning, single-button control and an easy-to-read, backlit LCD display to ensure clear viewing of gas level readings, alarm conditions and battery life. Data and event logging are available as standard, and there is a built-in 30-day advance warning when calibration is due.  

Why HVAC professionals are at risk from Carbon Monoxide – and how to manage it

Carbon Monoxide (CO) is an odourless, colourless and tasteless gas that is also highly toxic and potentially flammable (at higher levels: 10.9% Volume or 109,000ppm). It is produced by the incomplete combustion of fossil fuels such as wood, oil, coal, paraffin, LPG, petrol and natural gas. Many HVAC systems and units burn fossil fuels, so it’s not hard to see why HVAC professionals may be exposed to CO in their work. Perhaps you have, in the past, felt dizzy or nauseous, or had a headache during or after a job? In this blog post, we’ll look at CO and its effects, and consider how the risks can be managed.

How is CO generated?

As we have seen, CO is produced by incomplete combustion of fossil fuels. This generally happens where there is a general lack of maintenance, insufficient air – or the air is of insufficient quality – to allow complete combustion.

For example, the efficient combustion of natural gas generates carbon dioxide and water vapour. But if there is inadequate air where that combustion takes place, or if the air used for combustion becomes vitiated, combustion fails and produces soot and CO. If there is water vapour in the atmosphere, this can reduce the oxygen level still further and speed up CO production.

What are the dangers of CO?

Normally, the human body uses haemoglobin to transport oxygen via the bloodstream. However, it is easier for the haemoglobin to absorb and circulate CO than oxygen. Consequently, when there is CO around, danger arises because the body’s haemoglobin ‘prefers’ CO over oxygen. When the haemoglobin absorbs CO in this way, it becomes saturated with CO, which is promptly and efficiently transported to all parts of the body in the form of carboxyhaemoglobin.

This can cause a range of physical problems, depending on how much CO is in the air. For example:

200 parts per million (ppm) can cause headache in 2–3 hours.
400 ppm can cause headache and nausea in 1–2 hours, life threatening within 3 hours.
800 ppm can cause seizures, severe headaches and vomiting in under an hour, unconsciousness within 2 hours.
1,500 ppm can cause dizziness, nausea, and unconsciousness in under 20 minutes; death within 1 hour.
6,400 ppm can cause unconsciousness after two to three breaths; death within 15 minutes.

Why are HVAC workers at risk?

Some of the most common events in HVAC settings may lead to CO exposure, for example:

Working in confined spaces, such as basements or lofts.
Working on heating appliances that are malfunctioning, in a poor state of repair, and/or have broken or worn seals; blocked, cracked or collapsed flues and chimneys; allowing products of combustion to enter the working area.
Working on open-flued appliances, especially if the flue is spilling, ventilation is poor and/or the chimney is blocked.
Working on flue-less gas fires and/or cookers, especially where the room volume is of inadequate size and/or the ventilation is otherwise poor.

How much is too much?

The Health and Safety Executive (HSE) publishes a list of workplace exposure limits for many toxic substances, including CO. You can download the latest version free of charge from their website at www.hse.gov.uk/pubns/books/eh40.htm but at time of writing (November 2021) the limits for CO are:

Workplace Exposure Limit

Gas Formula CAS Number Long Term Exposure Limit
(8-hr TWA Reference Period)
Short Term Exposure Limit
(15-min Reference period)
Carbon monoxide CO 630-08-0 20ppm (parts per million) 100ppm (parts per million)

How can I stay safe and prove compliance?

The best way to protect yourself from the hazards of CO is be wearing a high quality, portable CO gas detector. Crowcon’s Clip for CO is a lightweight 93g personal gas detector that sounds at 90db alarm whenever the wearing is being exposed to 30 and 100 ppm CO. The Clip CO is a disposable portable gas detector that has a 2-year lifespan or a maximum of 2900 alarm minutes; whichever is sooner.

The risky side of default alarm settings

Logically, people assume the lower the gas detection alarm level, the safer the working environment, as the body will be exposed to less poisonous gas. However, this is not always the best option! If set too low, they can cause spurious alarms and unnecessary disruption. Worse still, these wolf cries have led to many incidents of detectors being ignored or switched off; with terrible results1.

Continue reading “The risky side of default alarm settings”

Accurate monitoring of exposure to toxic gases using TWA

Unique to T4, the TWA Resume function ensures toxic gas exposure is calculated accurately over an entire shift, even if T4 is switched off for a break or during travel to another site.

When most portable detectors are turned off, the algorithm that assesses TWA exposure assumes that it’s the end of the shift. When turned on again, these detectors act as if it is a new work shift, ignoring all previous measurements. The TWA Resume function however, provides the option to include previous measurements from within the correct time frame.