Are you Carbon Monoxide aware - It's not just a Domestic Boiler Problem?

Every week there seems to be a new article in the media with the two words we all fear – carbon monoxide…Very effective campaigns driven by The HSE, Gas Safe and other industry bodies have raised awareness of the danger, but to a degree this has been quite rightly focused on the Domestic Sector which is often unregulated, hence targeting owner occupiers with a campaign highlighting the dangers.

What is Carbon monoxide?

Carbon monoxide is a sneaky silent killer – it’s colourless, you can’t smell it and you can’t taste it – making it nigh on impossible to detect without the use of a Carbon monoxide detection systems. CO can kill quickly without warning, and according to recent HSE statistics on average 12 people die from CO poisoning every year, with non-fatalities (hospitalization) averaging 300 per year. (Source Below: RIDDOR: Table RIDGAS 2008/9-2012/13)


Incidents reported in Great Britain relating to the supply and use of flammable gas (a) 2008/09- 2012/13p

Type of incident (b) Year
2008/09 2009/10 2010/11 2011/12 2012/13p
Total number of incidents 203 223 278 173 219
Carbon monoxide poisoning 172 196 229 142 187
Other exposure e.g. to unburnt gas 4 6 13 7 6
Explosion/fire 27 21 36 24 26
Total number of fatalities 18 10 17 4 10
Carbon monoxide poisoning 15 9 13 3 9
Other exposure e.g. to unburnt gas 1 1 .-
Explosion/fire 2 1 3 1 1
Total number of non-fatalities 324 330 428 266 343
Carbon monoxide poisoning 289 292 368 226 302
Other exposure e.g. to unburnt gas 5 11 12 8 6
Explosion/fire 30 27 48 32 35

Below are a few notes on the above

Source: RIDDOR – Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995

Regulation 6 (1) of RIDDOR places a duty on certain conveyors of gas (including LPG), to notify HSE of an incident involving a fatal major injury that has occurred as a result of the distribution of supply of flammable gas.  The statistics published above are as reported to HSE.  When a report is made under Reg 6 (1), it will be at an early stage of incident, thus the detailed circumstances of the incident will not have been confirmed.

From 1 October 2013, RIDDOR changed slightly in respect of the above reporting criteria (‘RIDDOR 2013’ replacing ‘RIDDOR 95’).  However, this change does not currently affect the figures in the above table.  For more information please see ‘gas incidents’ at:

From September 2011 reporting arrangements changed, see: Summary of the effects to statistics for 2011/12 onwards

Provisional (a)  Mainly piped gas but also includes bottled LPG (b)  An incident can cause more than one fatality or injury General information on domestic gas safety is available at:

Sources and Common Causes

Carbon monoxide (CO) is a poisonous gas produced by incomplete combustion of carbon-based fuels, including gas, oil, petrol, wood and coal.  This normally occurs when a fuel burning appliance or item of plant has been installed incorrectly, badly repaired and or poorly maintained.  It can also occur when a flue, chimney or vent is blocked.  There have also been instances of well-maintained plant or systems failing resulting in CO emissions.

Residential Blocks, Multi-Occupancy Blocks, Commercial Buildings, Schools and numerous buildings will often have a centralised Plant Room or Energy Centre providing heating and hot water from fuel using equipment.  In the vast majority of instances these are well maintained, but even then can still be a potential source of this deadly hazard.

CO when it occurs will rapidly flood the confined plant room, it will also make its way out into occupied spaces within the property, possibly not of high enough concentration to be fatal, but certainly sufficient concentration to result in hospitalization.

These plant areas are generally unmanned, and when a possible issue is raised it is most often the concierge, porter, engineer or other authorised personnel who enter the plant room and succumb to carbon monoxide poisoning if present in sufficient concentration.

It is those ultimately deemed as in control of the building that need to ensure that as far as is practical all plant is installed and maintained correctly to prevent CO emissions, and importantly if a CO incident occurs safety systems are in place to prevent injury or harm to anyone with the potential to be affected.

Audible alarms may raise awareness of a problem, but the hazard is still present or being created until the item of plant or system is shut down.  This is fine if the property is manned, or the person attempting to deal with it is competent and understands the hazard.  If unmanned or unnoticed there is a high risk of a fatal incident and placing attending services at risk of harm.

It is our view that it is far more beneficial to install an integrated alarm system in these larger central plant areas, which not only detect CO emissions and sound an audible alarm, but also is linked into plant controls and will shut down the source, i.e. the boiler. By this method the environment will rapidly become safe for those entering the area and rapidly remove the potential of CO entering the occupied areas.  The short term loss of service far outweighs the potential injury or worse that could occur.

What are the symptoms of carbon monoxide poisoning?

The great danger of carbon monoxide is its attraction to haemoglobin in the bloodstream. When breathed in, carbon monoxide replaces the oxygen which cells need to function. When CO is present in the air, it rapidly accumulates in the blood, causing symptoms similar to the flu, such as headaches, fatigue, nausea, dizzy spells, confusion, and irritability.  As levels increase, vomiting, loss of consciousness, and eventually brain damage or death can result.

The symptoms for Carbon Monoxide are similar to the symptoms of flu, food poisoning and viral infections.  This is why many people are leaving it too late and in turn losing their life as they are mistaking this extremely dangerous poisoning for a common infection. co symptomsThere are six main symptoms of carbon monoxide poisoning:

  1. Headaches
  2. Nausea
  3. Dizziness
  4. Breathlessness
  5. Collapse
  6. Loss of consciousness

What can we do to prevent it?


Prevention is always the driving factor, so regardless of it being a Domestic or Commercial sized installation regular maintenance by a competent registered tradesman or company is essential.

In most instances Manufacturer’s instructions (MI’s) will advise an annual service which will include combustion analysis.  Best practice and experience, certainly in the non-domestic sector would advise a bi-annual check of combustion and condition, commonly referred to as an A (Major) and B (Minor) service schedule.  Dependant on the age of the equipment and general condition this may even be enhanced further.

Alarms and Monitoring Systems:

Currently there are no Statutory Obligations to install CO Alarms or Monitoring, it is felt that in the not too distant future this may change.  Advice from various industry bodies is to install or make provision for Alarms.  That said in the event of a reportable incident the HSE may focus on a system not being in place as part of a Duty of Care scenario.

The Domestic Market is easily catered for, with a simple Alarm, similar to a Fire/Smoke detector.

Within the Commercial sector, whilst this simple Alarm would at least give a local audible indication for those within the environment, the hazard given the likely size of the plant generating the problem will still be present.  An effective Monitoring-Alarm-Integrated Plant Shutdown would be far more appropriate.

Risk Assessment:

Check your premises Risk Assessment, has this potential hazard been noted? If not it is suggested this is re-visited.

Professional Advice:

If unsure refer to your service provider, they should be in a position to assist in understanding the Risk and provide effective solutions.