Aerotoxic Syndrome is the name given to the illness caused by the long-term effects of breathing contaminated cabin air in an aircraft. The term was introduced on 20th October 1999 by Dr Harry Hoffman, Professor Chris Winder and Jean Christophe Balouet, Ph.D.

The first well-documented case was of a C-130 Hercules navigator becoming incapacitated after breathing contaminated cabin air in 1977. The neuro-toxic properties of organophosphates have been known about since before the Second World War.

How could the cabin air be contaminated?

In order to have a comfortable environment and sufficient air pressure in the cabin to breathe at the altitudes at which airliners typically fly, a supply of warm compressed air is required. This is supplied direct from the engines and is known as "bleed air". It is mixed inside the aircraft with re-circulated cabin air at a ratio of about 50/50. Although some of the air is re-circulated; all of it originates in the engines. Bleed air comes from the compressor section of the engine which has many moving parts which have to be lubricated. There are various engine seals in place which are designed to keep the lubricating oil and air separate. Due to the design of these seal's "wet seals", they cannot be 100% effective, and will let a certain amount of oil into the air. They are also subject to wear, and like any mechanical component, they may fail. If a large amount of oil mixes with the very hot compressed air, the result will be fumes or smoke entering the cabin. There are no filters in the cabin air supply to stop this happening.

How could this affect passengers?

The type of oil used to lubricate plane engines is a complex, synthetic variety that has been specially formulated to endure extreme conditions. So naturally it is filled with all kinds of toxic components, including Tricresyl phosphate (TCP), a known neurotoxin that is used in pesticides and nerve agents.

Heavy metal particles such as nickel, cadmium and beryllium also make their way into the mix as the "bleed air" is drawn through engine channels. And because all of these different toxins are exposed to extremely hot engine air, there is no telling what effect this has on the existing contaminants.

According to the Aerotoxic Association (an association formed with the express intention of getting this syndrome recognised), these toxins cause damage to the central nervous system that vary from person to person. Some people may experience immediate symptoms while others may notice a pattern of illness that becomes progressively worse over time.

What would the symptoms be?

The symptoms of aerotoxic syndrome are many and varied. They may be provoked following one incident or may not come about until an individual had suffered several incidents. The people most affected to date, are air crew as it seems that the air in the cockpit could be most affected. However, this syndrome has not yet been officially recognised and results of a study into this syndrome are awaited from a study being carried out at Cranfield University.

Symptoms reported are not limited to, but include the following:-

Extreme fatigue - even after sleep

Blurred vision

Shaking and tremors

Loss of balance and vertigo

Memory impairment

Confusion and cognitive problems

Nausea/vomiting/diarrhoea

Breathlessness

Palpitations

Irritation of eyes, nose and upper airways

Is there a solution?

Research into new technology in planes to prevent the occurrence of toxic air entering the cabin (or indeed, to prevent the air being contaminated at all) is under way.

Masks are available from the Aerotoxic Association which may provide some protection during a flight.

http://www.aerotoxic.org/index.php/about-aerotoxic-syndrome