By K.S. Jayaraman

Bangalore, June 25 (IANS) Headache, breathing trouble and other unexplained illnesses in frequent fliers just might be the result of breathing toxic fumes circulating in commercial airline cabins, according to a report.

"Aerotoxic Syndrome", the unofficial name now being used to identify symptoms, is caused by breathing air contaminated with oil fumes leaking into aircraft cabins, it says.

The report has been prepared by London-based Aerotoxic Association founded by Former British Aerospace pilot John Hoyte and run by a group of aircrew "whose careers have ended prematurely due to Aerotoxic Syndrome".

The air inside the cockpit and cabin doesn't come from the "fresh air" outside the aircraft as one might think. The outside air is too cold and thin and in order to make it fit for breathing, it must be pressurized, heated, and then circulated to the passengers.

At first, planes were designed with mechanical compressors that produced clean, cabin air. But since the 1950s, most commercial planes have been redesigned to make cabin air - in a less expensive way - by drawing in a compressed supply of it from the plane's engines. Typically, this "bleed air" is mixed with existing cabin air and re-circulated throughout the flight.

In other words, the air in the passenger cabin is a mixture of re-circulated cabin air and fresh air that is compressed in the airplane engine. The problem is that the engine housing from where this air is drawn is often contaminated with toxic fumes from the hot oil used to lubricate the various moving parts of the engine. Sometimes so much oil mixes with air being drawn into the cabin that passengers will literally be able to see fumes and smoke filling the cabin - what is commonly referred to as a "fume event".

The synthetic oil used to lubricate plane engines is specially formulated to endure extreme conditions. It contains all kinds of toxic components, including 'tricresyl phosphate', an organophosphate that is used in pesticides and nerve agents and is known for its neurotoxin properties, the Association says. In addition, bleed air may contain particles of heavy metals from the engines, such as nickel, cadmium and beryllium.

According to the Aerotoxic Association, these toxins cause damage to the central nervous system that varies from person to person. The symptoms may include headaches, muscle tremors and signs of paralysis, blurred vision, light-headedness and dizziness. For some, the symptoms may be short-lived, but for others, persistent neurological damage may occur.

The Association report quotes from the numerous testimonies from pilots, air filtration experts, flight attendants and passengers who have been harmed by toxic cabin air.

The report said that virtually all jet aircraft and turboprops continue to use bleed air. The new Boeing 787 Dreamliner is the only type of plane that uses non-bleed technology and no longer takes air from the engines.

In a May 18 press release Independent Flight Attendants' Organization UFO in Europe demanded a comprehensive study of cabin contamination and also preventative measures such as filters and warning devices.

According to the Aerotoxic Association, an amendment has been introduced into the "Air Transportation Modernization and Safety Improvement Act" that would require the US Federal Aviation Administration to complete a study of cabin air quality within one year.