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Carbon Monoxide Detectors – The Unreported Facts

In 1958, I commenced a six year full-time apprenticeship in environmental engineering services to buildings, which included heating, ventilating, air conditioning, refrigeration and combustion, initially with Wm Bailey & Co. Ltd. followed by Harry Taylor of Ashton Ltd. During this time I attended at Manchester College of Building Science and Technology, for the theory, science and qualifications in these subjects.

I have also been employed by Lancashire County Council, as an engineering inspector, Oldham Metropolitan Borough Council as their senior engineer at their Civic Centre and in 1974 formed R & T Engineering Services. In 1989, I became a professional expert witness in environmental engineering services to buildings and in 1993 became a member of the Academy of Experts. In my career, I have been responsible for the design, installation, supervision and maintenance of such systems, and with the servicing of all the types of equipment necessary to achieve and perform their respective requirements. In addition to this I have been responsible for the training and supervision of students and apprentices under my control. In 1982, I together with two other partners/directors, introduced the first condensing gas fired boilers into the UK. For several years these type of heating boilers were refused to be accepted by the UK engineering fraternity.

I have been responsible for all types of design and installation work – from a small domestic heating system to large commercial and industrial installations. These installations have covered all services (hot and cold water services, low pressure hot water heating systems, many large steam projects, high pressure hot water heating, warm air heating, air conditioning, refrigeration, heat recovery, water filtration and purification, dehumidification, humidification, process heating, brick baking kilns, combustion of all carbonaceous fuel burning appliances (including oil from 22 sec – 2,000 sec), district heating (serving in excess of 3,500 properties), swimming pools, sports stadiums, dolphinariums, exhibition halls, animal and marine enclosures. Winner of the 1987 Norweb Peak Area BETA Award, for a heat recovery system used in the recovery of low grade heat in order to supply air conditioning to 2 council chambers at Oldham Borough Council.

Some of the clientele that I have served have comprised of many private individuals, numerous local authorities, government departments, ICI Limited, Trust House Forte, Jackson Brick Ltd., RSPCA, Manchester Dogs’ Home, Rolls-Royce, Derby and Crewe, Agfa-Gaevart Limited, Metal Box Co. Limited, R.T.Z. Metals Limited Universities, Shirley Institute, Union of Textile Industries Damascus Syria, Various NHS Hospitals, Probation Services, The Netherlands Air Force and various other overseas commissions, etc.

As a professional expert witness, I have acted upon instructions from solicitors and the Police in relation to litigation claims in connection with numerous actions that have resulted from various causations with refrigeration, air conditioning, heating (domestic, commercial and industrial), ventilation, industrial injuries, fire, explosions, control systems, water filtration, and numerous carbon monoxide related incidents which have caused injury as well as fatalities. One such fire case set a legal precedent.

Due to ill health and age I have been forced to resign from membership of all professional institutions.


LeanOnUs has been asked to publish the following letter by Mr Harry Rogers as Gas Advisor to Consumer Safety International (CSI) in response to a number of communications from Mr Gxxxxxxx to CSI. LeanOnUs DOES NOT wish to share it’s personal views in regard to this letter and so as not to cause ‘personal offence’ we have edited out some of the comments made within the letter. We do, however, feel it appropriate for the public to be aware of the comments by Mr Rogers and it welcomes a reply from CoGDEM.

(Letter ref: HR/LR/LJ1828/2, dated 29th January 2014 to Mrs M. Maher, Messrs Consumer Safety International, 310 Collier Row Lane, ROMFORD, Essex RM5 3NJ)


Dear Molly

Carbon Monoxide Alarms

I acknowledge receipt of your email in response to Mr Gxxxxxxx’s email (CoGDEM) and the appended previous email correspondence between you both.

It would be reasonable for me to assume that you are not aware that Mr Gxxxxxxx has recently plagiarised an article that had been written and presented by Mr Stephen Hadley,… (LeanOnUs edit and note – We have since received an apology from CoGDEM regarding copyright infringement)… Personally, and as far as I am aware, I have never met Mr Gxxxxxxx…(LeanOnUs edit)

Correct me if I am wrong but my understanding is that Mr Gxxxxxxx is the principal person within the organisation operating under the title name ‘CoGDEM’ (Council of Gas Detection & Environmental Monitoring). The use of the word Council, in itself, implies an official authority and/or approved organisation, as also does the title name of British Gas, which again implies an approval by some higher authority and in turn this would no doubt impress and mislead the average person… (LeanOnUs edit)

From the many lengthy documentation/correspondences which have been passed to me over numerous years it would appear that… (LeanOnUs edit) It would be reasonable to assume that if Mr Gxxxxxxx was correct in his numerous assertions then there would be a considerable number of educated, qualified and experienced persons that would agree with him, … (LeanOnUs edit)

You are already fully aware of my opinions regarding carbon monoxide (CO) alarms and their installation, which no doubt concurs with those of other members of Consumer Safety International. You are already familiar with my opinions regarding the necessary changes that are required to the Statutory Gas Safety (Installation and Use) Regulations 1998 (GSIUR), including amendments, (as given in my report reference number LJ.1878 dated 16th September 2010), with particular reference to Section 3:00, which covers the annual servicing of appliances. Firstly, it is paramount that all carbonaceous fuel burning appliances are installed correctly. Secondly, that they are fully serviced, on a regular basis (annually as a minimum), and not just checked for safety, i.e. inspected, as is the present requirement under the GSIUR regulations. Both of which must be pursuant to the Appliance Manufacturer’s Installation and Maintenance Instructions, as well as any relevant Statutory and Practical Accepted Standard (such as any British or European Standard). CO alarms should only ever be used as a secondary precautionary measure, as they are no substitute for compliance with the former. Furthermore, it is essential that the siting of each and every CO alarm is located correctly, when bearing in mind any installed or portable appliances and their respective use.

The above could be compared to the scenario that the normal sensible and responsible person may well have his motor vehicle regularly serviced, pursuant to the manufacturer’s instructions, from its date of purchase, yet that person may also have independent breakdown cover for the eventuality of a breakdown. Furthermore, in addition to the vehicle’s regular maintenance, the vehicle would have undoubtedly been constructed by the manufacturer and/or their agents, in the first instant and in addition to this, following its third year from initial registration, it is required, by law, to have a Ministry of Transport Test and Certificate (MOT), assuming that it is roadworthy. It will be appreciated that any motor vehicle, if not sensibly maintained and driven, will/can cause accidents and death. So can any carbonaceous fuel burning appliance. Why then is it that a similar requirement is not called upon for carbonaceous fuel burning appliances? After all, with a motor vehicle one can at least see and hear it, but with CO being a colourless and odourless substance it would be reasonable to assume that the safety standards regarding the installation, maintenance and safety issues would be considerably higher. Why are the same principles not applied to both scenarios?

I am informed that in 2011, the Gas Safety Trust, chaired at the time by Mr Chris Bielby, published its annual report. In this document, it stated that out of 11 CO incidents that had occurred, whereby CO alarms were installed, 5 (45%) failed to activate. Furthermore, during the course of my numerous investigations on numerous gas installations, when instructed against British Gas, I have been informed, by the end user, that British Gas’s engineers have informed them that CO alarms are a waste of time, that they are unreliable and should be placed in the dustbin. I also attach herewith various other cross reference articles relating to CO alarms.

Over past decades I, together with various colleagues, attended numerous meetings together with writing many letters, emails and reports in order to persuade various officials, such as the Health & Safety Executive (HSE), Advantica, Centrica, British Gas, Government Officials, CORGI (now trading as Gas Safe) and British Standards, all to no avail. (as given in my report reference number LJ.1878 dated 16th September 2010 with particular reference to Sections 2:08, 3:08 and 3:09). Eventually the flue gas analyser has now been adopted and employed as a tool to ascertain the emissions of CO from carbonaceous fuel burning appliances. However, these instruments have to be calibrated, tested and certified on at least an annual basis in order to be relatively certain as to their accuracy, particularly for safety. A similar scenario arose in the early 1970, at the time that I originally became self employed, wherein having heard about the use of an American portable electronic detection tool that could detect and warn of the presence of unburnt gas, I purchased several of these devices and distributed them amongst my employees. British Gas (a Nationalised Industry at the time) having heard about the employment of these devices, called me into their local head office and after a brief interview placed a restriction on me banning their future use. It is very strange that in later years British Gas employed and still uses today such electronic devices for the detection of fuel gas.

A vast amount of people are aware that aircraft are fitted with at least duplicate instrumentation, and sometimes even more, for obvious safety reasons. I accept that I am in no way qualified and skilled to the same level as Mr Gxxxxxxx in electronics. However, I am at a loss to understand how Mr Gxxxxxxx can place such a reliance on CO alarms when he cannot be fully aware of the quantity installed, their placement in relation to an appliance and its environment, the reliability of the electronic components and the current supply to the device. One does not have to be a ‘rocket scientist’ to appreciate that a CO alarm may well be the only sole device between a person’s injury and/or the resultant fatality of any end user(s), and that given the requirement that compulsory testing is required with instrumental flue gas analysers, then surely similar statutory requirements should be placed on CO alarms.

As most of you are aware several years ago the Department of Health commissioned a scientific research project to ascertain the effects of long term, low level, exposure from CO on the human body. Whilst all of the on-site tests/research relating to gas installations and appliances were completed by Dr Ben Croxford of the Bartlett School of Graduate Studies, University College London, the medical research effects, which was due to be carried out by the Medical Toxicology Unit, Guys & St. Thomas Hospital, was cancelled, by the Government before completion. Therefore, the only scientific studies that can be used as a reference are those recommended by the World Health Organisation’s Guidelines for Indoor Air Quality (WHO). However, what the on-site tests/research did identify was the large amount of appliances that were defective and emitting CO into the habitable space of properties. Initially I was involved in the on-site tests/investigations with Dr Croxford but unfortunately, due to ill health, I had to withdraw from the project. What the project did show was that it not only concurred with my own opinion, based on 40-plus years of experience, but that the proportion of appliances that were emitting CO into the inhabited space was, in fact, slightly higher than I had predicted, and that a relatively high proportion of the offending appliances were identified as the flueless appliances, i.e. the domestic cooker.

Could the reason behind consecutive British Governments not enforcing safety standards, and/or amending the GSIUR, is that they have been aware of the emissions that gas appliances have been polluting the habitable space of dwellings for many years, particularly flueless appliances such as the domestic gas cooker, and that they have done nothing to rectify the situation, and this is why the Department of Health dropped/abandoned the scientific research to be completed? Furthermore, given the fact that British Gas was originally a nationalised industry, and that during this period of nationalisation the Government of the day/British Gas certified the safe use of these appliances and thereby approved and promoted the use of flueless appliances, and realising the possibility of litigation, dropped/abandoned the scientific research before it was completed, thereby keeping the public at large in ignorance?

Many years ago I was asked, by the BBC ‘Hear and Now’ programme, as to what level is a safe level of CO to the human body. My reply was that, in my opinion, the safest level of CO is no CO. Many of you will be aware of the increasing number of people suffering from Alzheimer and Dementia. I accept that I am not medically qualified, but I am not aware of any research or medical claims that CO is or is not the causation or start of the disease. After all it is a medical scientific fact that exposure to CO, where it has not been fatal, can and does cause brain damage/deterioration.

The WHO state that the Guide Lines for CO is:

  • 87 ppm (15 minute exposure)

  • 52 ppm (30 minute exposure)

  • 26 ppm (1 hour exposure)

  • 9 ppm (8 hour exposure)

Mr Gxxxxxxx states in his email dated 2nd January 2014, to CSI:

‘We believe that the UK ’s experts in the testing of CO alarms are the HSE’s HSL test laboratory, the BSI test laboratory, the gas emergency services, the CO alarm manufacturers, the sensor manufacturers and CoGDEM. If any of these organisations had concerns about CO alarm unreliability and testing, there would be detailed evidence available and we would all be calling for a campaign to address any unreliability, but there are no such concerns. EN 50291-compliant CO alarms are very reliable.’

‘All of us in the CO community should be putting out consistent and correct messages about the use of EN 50291 compliant CO alarms. These alarms save lives and identify CO incidents way before they become emergencies. For example, our own CO alarm helpline received several calls over the Christmas period where CO alarm activations had identified genuine CO problems (one faulty wood-burner, one faulty gas fire and one poor quality Christmas candle arrangement in a small hallway!), but we had no calls about faulty or unreliable CO alarms.’

The HSE Research Report (RR847) that was prepared by the Health and Safety Laboratory, for the Health and Safety Executive 2011, states that the test procedures that were adopted were to BS EN 50291. The 300 ppm set point test as described in the standard was used. The test gas volume ratio used in the test was 330 ± 30 ppm CO in air. In order to pass the test the alarm should activate within 3 min. In addition, recovery from an alarm state was also tested, to prove its clean air recovery (zero) reading, after manual resetting if necessary, within 6 min when exposed to clean air. Note: none of the testing carried out by the HSE would appear to have been on a time waited basis.

Bearing in mind the WHO guide line level, as given above, (87 ppm CO in air for 15 minutes) and given that, say, the level of CO could be at 200 ppm (and the CO alarm had not alarmed), any adult would have a throbbing headache in less than one hour. What effect would this level have on a young child or pregnant lady? Furthermore, what overall long term low level effect would the CO have on any occupants within that space? Is the HSE, CoGDEM, Gas Safe Register, etc. prepared to guarantee any individual who purchases a CO alarm that they will not suffer any injury if they so used such a device?

Not having been presented with any circuit diagrams appertaining to any CO alarms, I am unable to give any opinion relating to the actual CO electrochemical sensor, as to whether or not it is actually tested under any test condition, and that the only available test condition (depressing the device’s test button) merely tests the device’s battery for current, the alarm’s circuitry and the audible alarm. I feel sure that any reasonable competent engineer would concur with me that any testing, by pressing any provided test button would not and cannot test the actual electrochemical sensor. Therefore, the only reliable, safe and practical test of any CO alarm can only be achieved by exposing the device to an actual known level of CO under laboratory-type conditions. It may well be that the use of infrared sensors would be a much better alternative, as opposed to electrochemical sensors which are presently used by the vast amount of CO alarm manufacturers. Furthermore, given that there may well be only one CO alarm fitted, surveying a number of appliances and, in the balance of probabilities, that alarm is not in the correct location, the risk of danger and or a fatality occurring is extremely high.

It may be prudent to note that no testing would appear to have been carried out regarding the audible levels of any CO alarm, which is imperative when bearing in mind that any fitted alarming device could be in a different room other than that of any of the building’s inhabitants and that interconnecting doors could be in a closed position, particularly at night-time, and that any audible alarm levels not only have to overcome the obstacles but awaken any respective personnel. Furthermore, no mention has been made, within the HSE Research Report, regarding the warning available to deaf and/or partially deaf personnel.

I accept the fact that the HSE Research Report has highlighted some major problems with the location and fitting of CO alarms, such as:

  1. The incorrect height of the location and fitting, therefore it would appear that the manufacturer’s installation instructions are not sufficient to ensure that any device is correctly located.

  2. The alarm device not being located near enough to a carbonaceous fuel burning appliance.

  3. Alarms are not designed to, and thereby do not, alarm if an internal fault develops such as failure of integral components and/or lack of power source to the device.

  4. The audibility of any alarming device.

  5. That more than one device may be required in the event of multi-fuel burning appliances.

  6. The device’s test button does not actually test the operation of the functioning and accuracy of the alarm’s inbuilt electrochemical sensor.

  7. It may be worthwhile considering and developing the application and use of infrared sensors, as opposed to electrochemical.

In addition to the above, page 22 of the report, paragraph 2, states:

‘The gas test performed in the study reported here was the highest CO concentration test in BS EN 50291 (300 ppm alarm level test). There are additional tests specified for certification to BS EN 50291 which require alarms to activate at lower CO concentrations but over longer periods, e.g. for the 100 ppm level, the alarm should activate between 10 and 40 min, and for the 50 ppm level, the alarm should activate between 10 and 40 min, and for the 50 ppm level it should activate between 60 and 90 min. It is not known whether the failure rate for these tests on the sample of alarms would be different to the rate for the high concentration test.’

When bearing in mind the WHO Guidelines, as indicated above, it is without doubt that the HSE testing does not indicate, in any way, that CO alarms give any indication and guidance, to the end user, as to their safety assurance with these Guidelines. However, I do concur with the HSE’s statement that ‘Audible carbon monoxide (CO) alarms are a useful back-up precaution, but they are not a substitute for the proper installation and maintenance of combustion heating appliances’. Whilst it will be for any individual to form their own opinion as to the safety and reliability surrounding CO alarms, I am of the opinion that much more development is needed with these devices, … (LeanOnUs edit)

As an experienced and qualified engineer in the environmental services industry for over 55 years, (including 30 years as a professional expert witness) which has included not only being able to design, install, maintain and supervise all types of commercial, industrial and domestic, heating, ventilating, air conditioning, refrigeration, heat recovery, combustion and controls, I would also be suitably capable of positioning, test and verifying the operation of CO alarms under the umbrella of such experience. However, with all due respect to the plumbing fraternity who may be very capable and skilled in plumbing, and given that in today’s modern environment the total lack of full apprenticeships in the heating and ventilating industry over the past decades, together with the fact that modern industry appears to now adopt the policy of only short-term training, it is my opinion that a plumber is far from being capable of carrying out such work. Therefore, it may well be that an industry is needed to recommend, install and test, on an annual basis, all CO monitors and/or alarms. Would it not be more practicable to ensure that the heating industry reverts back to implementing proper, full time, apprenticeships with technical training and examinations as was once the UK’s policy, with appliances being installed and serviced pursuant to the manufacturer’s instructions?

Molly, you are already aware of my opinions relating to the ‘Mafioso’ attitude by the politicians, Governments of the day, HSE, Centrica (British Gas & National Grid), BSI and the major gas operators in the industry, in that they have all acted negligently and incompetently towards the constant, repeated injuries and deaths that they have all contributed to by them not ensuring the highest safety standards and practices. I have always believed, by the attitude they have demonstrated to me, that it is a case of the ‘blind leading the blind’. When will they ever become more transparent and endeavour to listen to common, sound, engineering sense and stop ignoring their duty of care? Or is it that they are all making too much money and do not want the general public to realise the dangers they have been subjected to for many years and subsequently risk litigation claims? I trust that my response to your queries, and in particular those numerous repeated comments of Mr Gxxxxxxx, supplies you with some of the answers and probable logical reasoning behind the matter. This document is open to you relaying it to any/all interested parties.

Yours sincerely

Harry Rogers


As previously stated, LeanOnUs was asked to publish this letter and we felt that it was an important step to further raise awareness of carbon monoxide poisoning and the role of CO alarms. We felt that we should make the public aware of the comments by Mr Rogers and we welcome a reply from CoGDEM on this matter if they so wish.

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