On most commercial aircraft the cabin air is supplied by the compressor stage of the aircraft jet engines or auxiliary power unit. Compression of the air leads to the air being heated and under abnormal conditions, such as failure of an oil seal, any oils or greases this air comes into contact with will be heated and the contaminants arising may mix with the cabin air.
Cabin air quality events do occur and occupants can experience irritant effects due to the nature of these contaminants. There are concerns around long-term health effects resulting from exposure to contaminated cabin air. Some workers have cited the existence of an ‘aerotoxic syndrome’.
The existence of an aerotoxic syndrome is not universally accepted. However, it is said to be characterised by a collection of symptoms such as cough, tiredness and headaches that are otherwise common in the community, including those that do not fly. It becomes difficult to know if the symptoms are linked to exposures in the aircraft. The depth and complexity of the science required to establish such a link, if indeed such a link can be established, is considerable. Key experts in this area are clinical or medical toxicologists.
We are mindful that just as it is remiss to know of a potential threat to health and not bring it to wider attention, it is also remiss to overstate such a threat so that people are misled. In this regard, we do not believe that we have the expertise to state whether or not such links exist; we defer opinion on this to clinical toxicologists and their representative bodies such as Public Health England.
Whilst work is underway to investigate if such links exist, it is important to ensure the effectiveness of maintenance engineering practices so that the system works as intended. BALPA does work in this and other areas independently and as part of a European Cockpit Association working group.
For pilots that experience symptoms, or are concerned, we recommend they consult a doctor. For persisting symptoms or concerns we recommend that their doctor refers them to the regional NHS Poisons Unit where the opinion of a clinical toxicologist can be obtained.