Aerotoxic Syndrome

Have you experienced mysterious ill-health symptoms of chronic fatigue or neurological disorders after flying, symptoms generally summarised as being intoxicated, even though you weren't drinking on the plane? You may be suffering from 'Aerotoxic Syndrome'.

Where does the word 'Aerotoxic 'come from?

The term was first proposed in 1999 to describe the collection of ill-health symptoms observed in pilots, cabin crew and passengers after being exposed to toxic chemicals within the aircraft cabin.

Does "aerotoxic" refer to exhaust fumes or fuel vapours from aircraft which could be damaging to health?

No. Not many passengers realise that all of the 'fresh' air they breathe on most jet airliners has come part way through the jet engine. The high-pressure air is bled off (and called 'bleed air') then piped into the air conditioning units and finally into the cabin to provide the pressurised air needed to sustain life at high altitude, where the air is thin.

Before the mid 1960's all of the air on board was indeed fresh but then engineers discovered that they could save a lot of weight by using only bleed air. This is fine when the system is in good condition but, as with all mechanically driven equipment, it can become worn and leaky. The jet engine requires oil for lubrication and as it gets very hot it also takes surplus heat away.

What if this hot oil were to mix with the bleed air, which is then piped unfiltered into the cabin?

It is not too hard to imagine that on occasions, the oil fumes and air could mix to contaminate the air, which is then breathed by everybody on board from Royalty to economy passengers.

How might the oil fumes be dangerous?

Aircraft engine oil has a special additive called tricresyl phosphate or TCP. It is from a group of chemicals called organo-phosphates (OPs). These were originally designed many years ago to damage the central nervous system of living organisms but they were also found to have other properties. When added to oil, they make the engine last much longer and have some fire retardant properties.

In recent years there has been much talk about airline health ailments such as Deep Vein Thrombosis (DVT) and now researchers at The Research Institute for Sport and Exercise Sciences at John Moore's University in Liverpool have written in The Lancet that jet lag may affect passengers just as much as aircrew.

The symptoms of jetlag are poor and interrupted sleep, mood changes, headaches, irritability and gastrointestinal difficulties.

However, the warning on the oil tin and on Manufacturers' Chemical Data Sheets states:

Warning!
- Contains tricresyl phosphate (TCP)
- Swallowing this product can cause nervous system disorders including paralysis
- Prolonged or repeated breathing of oil mist, or prolonged or repeated skin contact can cause nervous system effects.

These are identical symptoms to those described above - and a possible cause of ill-health.

What then may be the cause of mysterious ill health on aircraft?

Jet lag or simply breathing contaminated air or a combination of both.

Extensive medical research by respected independent international scientists in recent years has shown that some pilots and cabin crew have become chronically and acutely sick from contaminated air, though equally many have no symptoms.

TCP has even been found on the walls of the aircraft by swab testing.

More than 100 UK MPs are now demanding that existing jet aircraft have filters fitted to remove any contaminants. Each filter system would cost around £15,000.

Fitting contaminated air detectors on board would also seem a sensible and long-overdue move on behalf of aircrew and passengers, who readily and trustingly place their health and well being in the hands of the airlines.

So why aren't aircraft manufacturers going back to the pre 1960's technology?

Coincidentally perhaps, that is exactly what is happening; jet engine bleed air is beginning to go out of fashion now in favour of electrically compressed air.

Furthermore, jet engine oils which do not contain organo-phosphates (chemicals which have been banned in many other industries) are available.

Aerotoxic Association has been specially set up by air crew who have been prematurely retired by ill-health to support, inform and represent other pilots, cabin crew, engineers and passengers. You may also worry that the aviation industry and governments are in denial due to 'lack of evidence'. Sadly, the evidence is overwhelming and any 'balance of probability' supports a serious problem.

If you have suffered ill-health after flying, check your symptoms with the Aerotoxic Association and discover the 'possible' real cause. If you are exposed to abnormal fumes on an aircraft and suffer mysterious ill health, the answer may be under your nose.

John Hoyte
Chairman Aerotoxic Association
www.aerotoxic.org
Former BAe 146 Training Captain