10.07.2025

Profitably poisoned cabins

Jim Moody reviews Tristan Loraine and Sandra Skibsted (directors) This is your captain speaking (screened at 2025 Raindance Film Festival). Distribution awaited

With tiresome queues through airport security over, air travellers aim to sit back in their seats and relax as best they can. But the air they breathe during the flight carries the kind of cocktail they would refuse if they had a choice.

This is your captain speaking relates the decades-long fight that cabin and flight crews have had to engage in against airlines in attempting to make their work environment healthy and not life-threatening. They are battling on to this day without much progress to show for it.

Co-directed by former airline pilot Tristan Loraine and experienced filmmaker Sandra Skibsted, this documentary is scathing in its exposure of many years of obfuscation, obstruction and inaction from airline operators and aircraft manufacturers that have also led to many millions of air travellers being exposed to toxic cabin air. Since the 1960s, when civilian jet travel took off, there have been an estimated 100 billion passenger journeys by air. While the film focuses primarily on aircraft as a work environment, featuring unions that organise aircrew, from flight attendants to pilots, its findings are relevant to every person who has ever flown or will fly in the near future.

Design flaw

Publicly unacknowledged, the basic problem is a design flaw, accepted as such by the aircraft industry, that has become integral to all jet engine planes since their widespread introduction over six decades ago. Propeller planes had used somewhat heavy, freestanding pumps to introduce and maintain clean air at breathable pressure in aircrew and passenger spaces while flying. But a cheaper option became available once jet engines were the universal means of aircraft propulsion: take ‘bleed air’ from around those engines, cool and pipe it directly into the aircraft. This is air taken from the compressor stage of the jet engine’s gas turbine, upstream of its fuel-burning sections.

Investigation by the film-makers uncovered ‘lost’ research in the public domain dating back to the 1950s, which showed that aircraft engineers at the time were fully aware of what was happening. And indeed, after early military jet pilots complained of fumes, fighter pilots have worn oxygen masks while flying. This obvious precaution speaks volumes: the fumes from even optimally functioning jet engines are too toxic to risk airforce pilots breathing it. But, when it comes to civil aircraft, apparently, anything goes. (Currently only Boeing 787 series planes are free of this particular problem; they use an electronically controlled air system.)

With the film’s researchers uncovering veiled layers of what was causing problems for those working on board civil airliners, the dangers are all too evident. The first and foremost problem derives from engine-oil additives - organophosphorus (OP) compounds designed to cut down engine corrosion. The most common of these is tricresyl phosphate (TCP). One of TCP’s three isomers has been known since the 1930s to be extremely toxic, having once mistakenly been used as a human abortifacient, with disabling and fatal results. In 1937, 60 South Africans were poisoned by contaminated cooking oil stored in lubrication oil drums; similarly, several thousand people in Morocco were poisoned in 1959 after using cooking oil contaminated with jet plane lubrication oil.

It is not as if the toxic effects of many OP compounds are unknown - what with warnings about the toxicity of OP pesticides and the resultant morbidity and mortality in individuals experiencing acute high-level exposure and chronic lower-level exposure. After all, several OPs with extremely high toxicity are used as chemical warfare agents. There are valid concerns that TCP and its variants can produce cancer, induce abortion and inflict serious neurological damage on foetuses during the first trimester of pregnancy, at a time when some women would not necessarily know they were pregnant. And, as stated in the film, there is no known safe limit - whether parts per million or parts per billion - up in the air. Few tests have been carried out on cabin air to determine how much pollutant is present in normal conditions or even during high-pollution spikes.

The film’s director took state-of-the-art test equipment on board while travelling as a passenger on several flights: he found pollution levels multiple times higher than in the domestic kitchen, which he had been officially informed was the benchmark level that would be present. Clearly, the official level was an invention. To this day, aircraft engines using oil containing OP additives still have air circulating around them bled into the aircraft cabin, and OP is but the most toxic component of a cocktail of compounds that independent testing has discovered in cabin air as a result.

Following extreme incidents of engine fumes in aircraft cabins - so-called ‘fume events’ - trade unions have brought some claims against airlines, but, apart from a very few isolated cases, they have been dismissed as ‘one-offs’ by company apologists. In other words, there has so far been no positive outcome for flight crews. Oversight authorities in leading capitalist countries, including the USA’s Federal Aviation Administration, were not at all keen to rock the boat and endanger those multimillions in profits that the aircraft industry enjoys. As one unnamed industrialist quoted in the film remarks, “The FAA doesn’t tell us what to do!”

As things stand, it seems that manufacturers of airframes and engines, as well as airline operators, are still untouchable, thanks to what is in effect bourgeois state protection. The UK’s Civil Aviation Authority implements international standards set by the International Civil Aviation Organisation, just like the FAA. The prime duty of the CAA - a public corporation of the department for transport - is to regulate aviation safety in the UK.

Oil loss

Misting in cabins during flight reflects oil loss in an engine, but this is the tip of the iceberg. At other times, while nothing more than a characteristic OP ‘smelly socks’ aroma pervades cabins, OP compounds - for which there are no safe levels of exposure - are still present in the air breathed for hours at a time by those assured they are being safely carried in that metal tube speeding through the sky. In addition, there are inevitably invisible particles and gaseous thermal breakdown products of fuel oil - almost certainly carcinogenic themselves. The CAA claims that onboard air circulation systems “remove bacteria, viruses and other particles” - but this is only effective if they are maintained and replaced at regular intervals. However, such mechanical filtration will not remove gaseous pollutants - that requires absorption at a molecular level. And, therefore, cabin air pollution continues, with the CAA muddying the waters to quell consumer and worker anger.

Go to the CAA webpage and you will have to drill down five levels before you find anything on cabin air quality.¹ What you get at that point is flannel. The CAA claims: “Based on the available data submitted through our Mandatory Occurrence Reporting process, occurrences relating to engine bleed air are rare, forming only a very small proportion of the total number of fume event reports we receive each year.” As the film reports, this reflects massive underreporting of serious events and is of dubious value in relation to ongoing pollution at a level that ‘merely’ causes sore eyes and throats.

Cavalierly, in its ‘Our statement on fume events’, the CAA also claims that when passengers do complain of “irritation to the eyes, nose and throat”, these “symptoms usually resolve once the fumes or smell have disappeared. Long-term ill health due to any toxic effect from cabin air is understood to be very unlikely, although such a link cannot be ruled out” (emphasis added). In fact, a major reason why long-term ill health cannot be ruled out is the absence of sensors installed on aircraft to detect and give warning to rising levels of OP and other components of the toxic air pumped from engines into the cabin. This delays emergency measures until it is almost too late; some incidents have led to the pilots being incapacitated during a flight. Both acute and chronic effects of inhaling such pollutants are indeed concerning to health professionals, precisely because they can lead to cancer, foetal abnormality and other long-term illnesses.

In its 2024 report, the Committee on the Toxicity of Chemicals in Food, Consumer Products and the Environment issued a statement on ‘Aircraft Cabin Air Quality’,² which says in part: “Regarding OPs, the committee concluded that it was unlikely that exposure to organophosphates at the low levels reported in aircraft cabin air would have adverse effects on aircrew” (emphasis added). Of course, “unlikely” here is the universal saviour of expert opinion. Other experts beg to differ, as evidenced in the film. When one was asked what was the safe limit for TCP, he answered, “Zero”. And indeed, while the effect on aircrew is most important, the effect on ordinary passengers is hardly considered.

The lack of progress in resolving this danger in favour of crew and passengers suggests more direct means, by unions especially, are needed. Industrial action to force the aviation industry to act and protect workers’ health must surely be on the table. In parallel, the rights of air travellers not to be poisoned ranks highly in what any political organisation of the working class needs to add to its campaigning armoury - which, of course, means communist parties in every country of the world. This is a worldwide problem, after all.