10 Confined Space Hazards

Top 10 Confined Space Hazards and How to Minimise Them

A confined space.

Summary of Contents:


Recognising a danger is one thing, but that, in itself, is insufficient when it comes to protecting the health and safety of your workforce. Management of Health and Safety at Work Regulations 1999 legally require employers to identify the hazards in their workplace and put in place measures to control any and all health and safety risks they pose. In other words, not only should hazards be identified, but steps should then be taken to reduce any danger associated with an identified hazard.  Failure to do anything to reduce that danger is tantamount to negligence and can lead to a criminal prosecution


Failure to identify a confined space 

By dint of their unique characteristics, confined spaces bring with them a unique set of hazards and risks that one would not expect to encounter in other working environments. Therefore, it makes sense that the first hazard to overcome where confined spaces is concerned priority is to identify whether or not the location where work is to be carried out is a confined space. The Commodious course on Confined Spaces will provide you with invaluable information when it comes to their identification.


Failure to identify a confined space hazard 

Believe it or not, but the most significant risk associated with working in confined spaces is the failure to identify a risk. In other words, before performing any tasks to be carried out in a confined space, a risk assessment needs to be completed. You will find the Commodious course on how to carry out a risk assessment extremely beneficial. Where confined spaces are involved, risk identification involves forward thinking, something not always associated with risk assessment. By forward thinking, we are referring to potential hazards which do not exist when work commences but can occur once work has commenced. Such risks are included in the list we provide in this article, but examples here include reduction in oxygen levels and/or increase in the build-up of toxic fumes.


Reduced oxygen levels in confined spaces

For the fact that a space is confined, this will usually mean that air circulation can be limited. While oxygen levels within a confined space can be perfectly acceptable at the beginning, those levels can soon change once work commences, especially if the work is arduous in nature. Not only do oxygen levels reduce, but carbon dioxide levels increase, so a lack of oxygen can develop subtly and may initially go unnoticed. The result is a life-threatening medical condition called hypoxia. There are several solutions available to counteract a reduction in oxygen levels, which include the installation of temporary ventilation equipment or, in extreme circumstances, the wearing of breathing apparatus that is not dissimilar to that worn by members of the Fire Services. It should be noted that one solution that should never be used to raise oxygen levels in a confined space is to inject pure oxygen into the atmosphere. The reason for this is that while oxygen itself is not flammable, it can help other materials burn more easily, more forcefully and more rapidly, to the point of creating an explosion-like situation.


A build-up of noxious fumes and gases in confined spaces

Build up of noxious fumes and gases in confined space.

While a lack of oxygen can be one consequence of poor air circulation in a confined space, that poor air circulation can also lead to a build-up of poisonous or noxious fumes. Examples of this can be from welding, or the disturbance of materials already in the confined space, such as slurry or food waste. Once again, the introduction of a temporary ventilation system, ideally with carbon filters, or the wearing of appropriate breathing apparatus can mitigate the problems created by the build up of noxious fumes.


A build-up of combustible fumes in confined spaces 

The risk of a 'gas explosion' is greatly increased when looked at in the context of confined spaces. One of the greatest culprits is methane, a highly combustible hydrocarbon-based gas which is heavier than air, and therefore can easily build up in a workplace environment. The classic environment where methane gas has been a historic killer has been down coal mines. the next three most common explosive gases are hydrogen, oxygen and acetylene. Note that there is a difference between an explosive gas, which includes oxygen, and a flammable gas, which excludes oxygen.

Unlike mitigating for the build-up of noxious fumes, wearing breathing apparatus does not reduce the risk of an explosion resulting from the presence of a combustible gas. To mitigate the risk of a gas explosion, the presence of an explosive gas must be substantially reduced to a safe or negligible level. This can be achieved by eliminating the source, greatly increasing ventilation, and using working practices and tools that minimise the risk of creating any form of ignition for combustible gases.


Flooding in confined spaces 

When one mentions flooding, one automatically thinks of liquids, and primarily water. It cannot be stressed strongly enough that there are certain solids that are just as dangerous as water when it comes to flooding, including, grain or flour in silos, and earthworks surrounding tunnels which can flood the space if the tunnel collapses. Flooding in confined spaces is particularly dangerous in a confined space. First, movement if often restricted in a confined space, while access and egress are also often restricted, making it harder to escape the flood. Additionally, the nature of a confined space is such that the material causing the flood has restricted means of escape. To minimise the risk of flooding in a confined space, it may be worth considering creating a temporary means of escape for either the person/people doing the work, or the material causing the flood. The wearing of a safety harness and ensuring you are not alone, that you are being supervised can help with taking appropriate emergency action in a crisis situation.


Dust in confined spaces 

Dust can pose a dual threat when it comes to confined spaces. Firstly, it can cause severe respiratory problems and restrict breathing. Second, depending on the constituents of the dust, it can also have explosive properties. As an example, in the food industry alone not only is flour dust highly explosive, but dust from custard powder, instant coffee, sugar, dried milk, potato powder and soup powder are all highly explosive. From the point of view of respiratory protection, dust and face masks should ideally be worn in any environment where dust is a problem, whether or not it is explosive dust. To mitigate risks of an explosion form dust, cleanliness is one of the major parameters to avoid any unnecessary build-up of dust. Air filters will also be a necessity for any ventilation system. If you would like to learn more about controlling dust consider reading our detailed article: Controlling dust in the workplace.


Excessive heat and cold in confined spaces 

Both excessive heat and cold can be killers, and especially confined spaces in the workplace. A walk-in industrial freezer is the perfect example of a cold, confined space, the area being confined as access is usually restricted to one opening/exit. Heat is just as dangerous and isn't always such an obvious danger. This is because we frequently get hotter the longer we work in a confined space, especially if other health and safety requirements require us to wear personal protective clothing, or PPE as it is often referred to. So, while PPE may be required to protect us from, say, harmful chemicals, the protective suit could cause our body temperature to rise to a dangerous level. Above 38oC or below 36oC is a normal temperature range, while below 32oC and above 43oC can be fatal. 

One of the best ways to mitigate the dangers of working in hot, cold, or potentially hot or cold environments is to limit the length of time you spend on the task at hand.


Access restrictions in confined spaces

One of the problems with working in confined spaces is that often it is restricted access which creates the confined space in the first place. In some circumstances, it may be necessary to create additional access/egress points, but this will not always be practical. In such a case, an emergency escape plan needs to be created so that if anything goes wrong, rather than panic, an escape procedure can be implemented and followed.


Working alone in a confined space

Working alone brings with it its own set of risks and dangers. Add those to the increased risks created by having to work in a confined space, and it is clear why additional precautions need to be taken. For example, in the event a worker falls and is knocked unconscious, if there is nobody there to check on them, they could remain there, unnoticed until it is too late to help. Similarly, if working in a confined space that has a flooding risk, invariably an emergency will likely require outside assistance. Because companies frequently look at the bottom line, profitability, when it comes to allocating workforces for specific tasks, allocating an individual to act as a supervisor for someone actually doing the work can seem like an unprofitable move. However, in many instances, accidents in confined spaces could have been less serious if there had been someone else present to either act themselves to help, or who could call upon appropriate help. 


We have created a separate course on Lone Working which you may find helpful.

Here at Commodious we specialise in providing online courses that cover many aspects of Health & Safety at work. If you would like to learn more about any of these, please feel free to get in contact with us.