top of page
  • rradar

Carbon Monoxide Hazards

Updated: Feb 16

A construction firm has been sentenced for safety breaches after workers were exposed to carbon monoxide and other substances hazardous to health.

The Magistrates Court heard how the workers were using a petrol-powered saw to cut out an existing concrete floor at a fish factory. In order to protect the food factory surfaces from dust, they constructed a sealed enclosure from timber and polythene. The workers were inside the area working over a weekend, the space was not ventilated and there was a build-up of carbon monoxide, which lead to one worker being hospitalised.

An investigation by the Health and Safety Executive found the company had not planned the work or thought through the dangers an unventilated tent would cause. The company should have used a system of dust suppression and local exhaust ventilation (LEV) together with appropriate respiratory protective equipment to prevent or reduce exposure to harmful dust.

The company pleaded guilty to breaching Section 3 (1) of the Health and Safety at Work Act 1974 and was fined £16,000 with £847.30 costs by the Magistrates Court.

When Carbon Monoxide poisoning is mentioned, many people think of faulty boilers in domestic situations, but as the case outlined above shows, it can happen anywhere that combustion is taking place in an enclosed space.

What is carbon monoxide?

Carbon monoxide (CO) is a gas produced when carbon-based fuels (including gas, oil, wood and coal) burn incompletely.

When carbon monoxide is inhaled, it stops the blood from bringing oxygen to cells, tissues, and organs. Because it is odourless, colourless and tasteless, it can kill quickly without warning as large amounts are breathed in without the victim realising that anything is wrong.

Even if the gas does not kill, it can cause serious harm to health if breathed in over a long period. In extreme cases, paralysis and brain damage can be caused as a result of prolonged exposure.

The symptoms of carbon monoxide poisoning

It is often difficult to recognise carbon monoxide poisoning as its early symptoms can be similar to a variety of other ailments, including food poisoning, viral infections, flu or simple tiredness.

Employers and employees should be aware of the following symptoms:

  • Headaches or dizziness

  • Breathlessness

  • Nausea

  • Loss of consciousness

  • Tiredness

  • Pains in the chest or stomach

  • Erratic behaviour

  • Visual problems

What employers should do

The COSHH (Control of Substances Hazardous to Health) Regulations impose a duty on employers to protect against the risks from carbon monoxide. This can be achieved using the Assess/Control/Review model, which operates as follows:


Tasks or situations where significant levels of carbon monoxide may occur should be identified and assessed. Such situations can include:

  • Operating LPG equipment in enclosed spaces (for example, work equipment, heaters or cookers in welfare facilities such as restrooms or kitchens)

  • The use of petrol-powered work equipment or tools in enclosed areas, such as trenches or excavations where the carbon monoxide will not be dispersed by air currents or wind.

  • Refurbishment of existing buildings where gas flues or ventilations systems have been blocked or disabled by building work

Employees who are carrying out work in the open or in a well-ventilated space are at lower risk.


Wherever possible, the risks of carbon monoxide should be eliminated or reduced. Steps that can be taken to achieve this include:

  • the use of electrical or battery driven appliances instead of ones that use petrol or LPG;

  • siting generators in outside locations or in areas that are well-ventilated;

  • assessing the effect of refurbishment work on existing gas-fired systems.

However, even if some of the risks are minimised by the use of the steps outlined above, there are other activities that may still create a carbon monoxide risk. These can be controlled by:

Ventilation – any activities that are using LPG or petrol-powered equipment or tools should take place in areas that are well-ventilated, both at high and low level.

An inspection should be carried out before each use to make sure that there are no blockages (such as vegetation or ad hoc ‘draught excluders’) that will prevent the ventilation from working properly.

Detectors – carbon monoxide detectors should be used where appropriate. These can either be personal detectors worn on clothing or a detector that is sited in the area where the activity is taking place.

Training: Systems should be put in place to ensure that all employees taking part in activities that may generate carbon monoxide are aware of what they need to do and how to use the control systems that have been put in place. They should also be aware of the symptoms of carbon monoxide poisoning and what to do if they suspect that somebody is suffering from it.


Supervise: the employer should establish supervisory measures that ensure the controls that have been put in place are being used properly by employees and are effective in preventing carbon monoxide poisoning.

rradar offers a range of legal advice and support as well as innovative digital tools to help your business achieve legal freedom.

To find out how we can help your business, please call 01482 296 800 or email

Need to contact us?

For all media related enquiries, please contact us on

bottom of page