And what about Aviation’s Wounded Canaries?
By Bearnairdine Beaumont
Published 21 April 2024
Photo - Cage for reviving canary, with oxygen cylinder, made by Siebe Gorman & Co. Ltd, London © image Science Museum Collection
The beautiful yellow birds, Canaries, were used in mines in the late 1800s to detect gaseous fumes, such as carbon monoxide. Gas is deadly to humans, especially in large quantities. Canaries are much more sensitive to even small amounts of gas and will therefore react more quickly than humans.
John Scott Haldane, a British physiologist and philosopher chiefly noted for his work on the physiology of respiration was called in to investigate the cause of an explosion in a mine at Tylorstown Colliery in 1896. He concluded that a carbon monoxide buildup was the cause of the explosion. He started working on developing a method for identifying the colorless gas before it could endanger humans. Among his most widely used devices was the hemoglobinometer, an apparatus for the analysis of blood gas, and an apparatus for the analysis of mixtures of gases. In a paper he sent to the British Home Secretary, Haldane recommended that miners take a small animal, a mouse, for example, with them into the mines since they have a higher relative metabolism than humans and would show signs of toxic fumes and subsequent poisoning sooner. Canaries were soon being regularly brought into mines by UK miners as a safety measure.
Haldane invented the cage shown above in the picture, also to protect the little sentinels. The round entrance was kept open and had a grate to prevent the canary from escaping. If the canary showed signs of toxic fumes poisoning, a valve would be opened and the door closed. By doing that, the oxygen in the tank above was released, helping to revive the canary by breathing fresh air. The miners had to evacuate the hazardous area immediately.
Many miners cared deeply for their canary companions, and some didn't like the advent of electronic sensors when British legislation officially ordered them to replace canaries on December 30, 1986, because it meant losing that companionship. I though, am relieved that it ended since I feel so bad for the small birds because I know firsthand how sick poisonous fumes can make people.
Aviation’s Canaries
From the depths of the dark coal mines to high up in the air: toxic fumes in aircraft. My question remains, and my readers who have been following my articles know why I ask: Why is there still no (British or other countries) legislation ordering devices onboard aircraft that quickly and efficiently detect toxic engine oil and exhaust fumes that can enter the passenger cabin via the engine bleed air?
These fumes contain a multitude of toxic substances, that are even more dangerous than the fairly low levels of carbon monoxide that can also be present. Certain chemicals in the toxic soup have been determined to be endocrine and fertility-damaging, carcinogenic, and can cause immediate nervous system reactions such as dizziness, tunnel and other vision problems, headache, tremors, loss of concentration, and confusion.
Needless to say how dangerous to the health and safety of everybody on board this can be, especially when one or worse both pilots should suffer from mentioned effects. If they are confused and don’t react quickly enough and don’t put on their oxygen masks immediately - well, I don’t even want to think about it!
I can assure you that pilots and cabin crew, particularly those who have endured the harrowing experience of acute toxic fumes poisonings while in flight and subsequent chronic ill health, loss of medical license, loss of lively hood, and their dream, would have been extremely grateful to have had toxic fumes warning devices installed in their aircraft so they wouldn't have had to be, in the end "the wounded canary”.
An “electronic nose”, a device that makes everybody quickly aware that there is an air contamination problem that needs to be dealt with - before pilots, cabin crew, and passengers suffer symptoms of poisoning, does not cost the world, but could be bad for reputation: it would be going off “all the time”.
On top of there not being an electronic measuring device on board, and of course no way to evacuate immediately, there also isn't any medical oxygen on every aircraft (Note: to release the overhead masks would be of no help since they supply a mix of oxygen and cabin air). Not every airline supplies emergency medical kits that include O2 for a “quick fix” to use in the way John Haldane created one for the canaries - (only the pilots have oxygen masks). It’s the human nose that acts as a “device” and then not everybody recognizes a “smell” as one that shouldn’t be there. Another problem is that the human nose, respectively the olfactory nerves can get used to even an unpleasant smell within minutes, even seconds, and the person thinks it is gone when it is not. And then, just like the previously unprotected bird that stopped singing and fainted from the lack of oxygen and intake of poisonous gasses, human beings, mostly crew members become “the canaries” and suffer the consequences.
And that is the reason why I named my blog (and my second book’s subtitle): Aviation’s Wounded Canaries.’
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We know that carbon monoxide has been detected and contributes to the problem of toxic air in airplanes. In fact, it’s often the only type of toxicology test offered to airline crew in hospitals following onboard fume events, hence many crew being led to believe that their health issues are purely CO related.
Unfortunately, the problem of toxic air onboard aircraft is far more complex due to the immense number of chemicals involved, some of which are known to have synergistic effects with others in the mixture, making them more toxic.
It was known in the early 1990’s that ‘organic and inorganic phosphates can evolve products on heating capable of forming OP esters not present in the original material, which can account for a high percentage of the available phosphorus (50% or more).’
- Clinical & Experimental Toxicology of Organophosphates & Carabmates
Written by B. Ballantyne & T.C. Marrs Published 16th March 1992.
Studies have shown that the ongoing health effects of miners exposed to carbon monoxide are different from those of airplane crews exposed to polluted air onboard aircraft which is exposure to a mixture containing a multitude of toxic substances:
‘The pattern of autonomic dysfunctions in the aircrews is distinctively different from that in miners exposed to carbon monoxide’ as explained in evidence given to The House of Lords Science and Technology Committee Enquiry into Aircraft Cabin Air of 2007 - which, incidentally no one with any horsepower within the U.K. Government or Medical Community took any notice of -
Letter from Dr Peter Julu, Specialist Autonomic Neurophysiologist and Consultant Physician
‘EARLY EVIDENCE OF SPECIFIC AUTONOMIC NEUROPATHY IN AIRCREWS
I have carried out target-organ specific examination of the autonomic nervous system in a group of aircrews (n = 9) who developed chronic neurological symptoms during the course of their duties and compared the outcomes with a group of coal miners (n = 6) who also became ill following exposure to carbon monoxide due to ventilation accidents, in order to establish the pattern of autonomic dysfunctions in the two groups. The neurological sequelae I found in miners exposed to carbon monoxide and aircrews complaining of ill health consist of a patchy pattern of dysfunctions of the autonomic target organs in various parts of body but mainly in the skin, in the large blood vessels including the heart and in the brain. These neurological sequelae can explain the symptoms and ill health in these two groups of patients. Cholinergic functions are selectively preserved while monoaminergic functions deteriorate in the brain and in the skin among the aircrews. The imbalance between cholinergic and monoaminergic functions in the brain can explain cognitive dysfunction and impairment of short-term memory. The pattern of autonomic dysfunctions in the aircrews is distinctively different from that in miners exposed to carbon monoxide.
I am continuing to see more aircrews in my clinics and the pattern of autonomic dysfunctions in these patients is consistent. This is a compelling reason for further investigation, first to confirm the findings in the aircrews by examining a larger number and then to investigate possible common toxic agents among sheep farmers and aircrews. This is so because the pattern of autonomic dysfunctions in sheep farmers and the aircrews is identical.’
17 June 2007
https://publications.parliament.uk/pa/ld200708/ldselect/ldsctech/7/7we15.htm
Sadly, there were no further investigations of aircrews or on the common toxic agents among farmers and aircrews. Although, the alarm was sounded a long time ago and is highlighted in this document from 2002 in relation to farmers affected by pesticide and sheep dip mixtures containing organophosphates.
‘The peripheral nerve involvement in OP exposure is predominantly sensory in nature affecting both small and large fibre populations. Neurobehavioral involvement of mainly cognitive dysfunction and other features are also described in other studies. The weight of current evidence is therefore very much in favor of the motion that chronic low-level exposure to OP produces neurotoxicity. Criticisms levelled against this motion are unfounded and probably misconceived.’
https://www.sciencedirect.com/science/article/abs/pii/S0300483X0200447X
It’s important to note that exposures to organophosphates (OP’s) in the case of pesticides, aircraft oil and hydraulic fluid are exposures to mixtures of chemicals which contain organophosphates and not exposure to pure organophosphates.
Many aircrew have evidence of some of the chemicals used in aircraft oil and hydraulic fluid being present in their bodies from fat cell biopsies performed at specialist environmental clinics which include Xylene, Benzene and Trichloroethane (and many others).
Some of the common toxic agents used in pesticide mixtures as well as aircraft oil and hydraulic fluid are Xylene, Benzene, Trichloroethane (and their derivatives) as well as Organophosphates which are neurotoxins.
These chemicals are all known to be Endocrine Disrupting Chemicals which are associated with several adverse health outcomes, including altered immune function, various cancers, disrupted systemic metabolism, disrupted nervous system function, reproductive dysfunction and developmental malformations.
Endocrine Effects - Trichloroethane as an example:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6290898/
Endocrine Effects - Overview - US EPA (2024)
https://www.epa.gov/endocrine-disruption/overview-endocrine-disruption
Unfortunately, the U.K. Government holds no information on Endocrine Disrupting Chemicals or the effects from repeated low-level exposure. They continue to tell Airline Crew that the levels or doses of chemicals they have been exposed to onboard aircraft are too low to cause injury (exposure levels and doses set by research from the chemical industry).
The U.K. Government’s Committee on Toxicity (COT) & Food Standards Agency (FSA) have not compiled a list of Endocrine Disrupting Chemicals as confirmed through a recent Freedom of Information Request and has suggested I search for the relevant literature online.
This document was produced by the European Parliament in 2019:
https://www.europarl.europa.eu/RegData/etudes/STUD/2019/608866/IPOL_STU(2019)608866_EN.pdf
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Also -
The GCAQE are holding a conference on Aircraft Cabin Air on 17th and 18th September 2024 at Imperial College London.
This may be of interest to those who hold senior positions within the Aviation Industry, National Health Service and the U.K. Government Departments for Transport and Health.
Tickets are available here:
https://www.eventbrite.com/e/aircraft-cabin-air-conference-2024-tickets-782620217137
Thank you.