Solution to cabin air contamination looms

Aircraft cabin air contamination, a persistent issue for airlines because their crew and passengers face the risk of consequent neurological harm, may soon be alleviated by advances in chemical science, according to a new scientific paper published in the UK-based Journal of Hazardous Materials.

The study, sponsored by French industrial lubricant manufacturer NYCO, says: “The research underscores the urgency to replace hazardous industrial OPs [organophosphates] due to their documented neurotoxic effects and associated risks.” The study states analysis of OP chemical structures reveals that “one of the identified clusters had a favourable safety profile, which may help identify safer OPs for industrial applications”. Those applications include aero-engine lubricants, which at present are proven to be the source of contaminants released into aircraft air conditioning systems when “fume events” occur. NYCO has, for years, been researching the possibility of producing aero engine lubricants that are as effective as existing ones, but less toxic.

Findings and consequences from the paper, entitled “Organophosphate toxicity patterns: A new approach for assessing organophosphate neurotoxicity”, will be revealed at the 17-18 September 2024 Aircraft Cabin Air Conference at Imperial College, London.

Also to be presented at the conference is the detail of new tests on passengers and crew that can reveal “biomarkers” in their blood proving that they have been exposed to toxins specific to aircraft cabin air contamination, enabling appropriate remedial actions to be taken by those affected.

In terms of mitigation options while the OP risk to airline passengers and crew remains at its present level, also presenting at the conference are Sweden-based CTT on the subject of cabin air humidification and active carbon filters; BASF on dealing with volatile organic compounds and ozone conversion; and PTI Technologies which will reveal its latest bleed air filtration capabilities.

Dodging the verdict

Hundreds of airline pilots and cabin crew who have had their health permanently damaged by neurotoxins in aircraft cabin air joined a three-day multinational conference in late June to hear about the latest technical and legal solutions to the problems they face.

Hosted in London, England, the online Aircraft Cabin Air Conference drew in speakers and delegates from all time zones. Developments revealed at the event include a new blood test that scientifically confirms exposure to the specific organophosphates in jet engine oils that cause the harm by leaking into the engine bleed air that ventilates the cabin.

Also revealed was a new regulation to aid exposed crews and passengers: the US Cabin Air Safety Act. The purpose of the Act is to “improve the safety of the air supply on aircraft”, and it requires that all flight crew, maintenance technicians and airport first responders are to be given training – at least annually – on how to respond to “incidents onboard involving smoke or fumes”.

Meanwhile, in recent years, many medically harmed crew-members have – individually – been financially compensated by their employers for consequential health damage, but the air transport industry as a whole is still able to turn a blind eye to this fully understood phenomenon.

The reason the industry – the airlines themselves and the aircraft and engine manufacturers – appear to get away with tolerating such a recurring phenomenon is simple. Whenever they are challenged in the courts over cases of human health damage caused by contaminated cabin air, the companies settle out of court with the plaintiffs, who desperately need the compensation money because their career – as well as their health – is in ruins. So, the court does not get as far as delivering an actual verdict on the harm, the cause, or the blame.

Meanwhile a US law company, Littlepage Booth and Athea, has assembled a formidable body of technical and medical evidence on the effects of contaminated cabin air while representing harmed individual clients. The specific evidence these lawyers have gathered implicates only Boeing. That is purely because – they say – Airbus is a more complex legal task to take on in the USA.

Ironically, the only modern airliner in service today that does not use engine bleed air for air conditioning and pressurization is Boeing’s own 787, the most recent entirely new aircraft off its production line. The company explains it has abandoned the bleed air system in the 787 for fuel consumption reasons. But the 787 – also uniquely – does not use bleed air from its auxiliary power unit (APU) for cabin air ventilation, although there is no fuel consumption advantage in so doing. Law company partner Zoe Littlepage confirmed that the body of evidence against the manufacturer may be extensive, but until a trial has gone all the way through the courts and a verdict is reached, the status quo will remain.

The organophosphate contamination of cabin air is caused when aero-engine oil and/or hydraulic fluid leaks into the cabin air conditioning system, the air supply for which is drawn from the jet engine compressors. This contamination is not supposed to happen, but from time to time “fume events” occur when an engine bearing fails and the vaporized synthetic lubricants are “pyrolized” – partially burned – by the hot compressed air – and mixed into the cabin air that the pilots, cabin crew and passengers breathe. There is no filtration of this “bleed air” supply, and no detection systems to warn those on board when contamination is present. There is, however, usually an unpleasant smell, and sometimes visible smoke.

Pilots and cabin crew are more at risk than passengers, because even undamaged oil seals are not perfect, and there is constant leakage of the heated oil vapors in the bleed air into the cabin air at a very low rate. In some individual crew, the inherent toxins can slowly build up in their metabolism through repeated exposure, and because “aerotoxic syndrome” is still not legally recognized by the authorities, non-specialist medical doctors are unlikely to make a correct diagnosis of the resulting symptoms.

The authorities claim these very low rates of leaked fumes are acceptable, but that cannot be so because there is no designated rate or dose of these organophosphate-based neurotoxins that is defined as acceptable.

Fume events, on the other hand, are potentially dangerous to all. Passengers, however, are not generally warned of the risks when an event has occurred, and frequently the occurrence is not reported. And if – later – passengers suffer symptoms like persistent excessive tiredness, dizziness or “brain fog”, they may not connect their problems to their flight, and their doctor is unlikely to diagnose the problem accurately.

And so it goes on.