CONTAMINATED cabin air on planes is like “sticking a pipe from your exhaust into your car”, a former pilot and leading researcher has warned.

Dr Susan Michaelis said air crew and frequent fliers are being let down by gaps in health and safety regulation which allow the regulators to “turn a blind eye” to the hazard of chronic exposure to low doses of poisonous chemicals in cabin air, as well as high-dose “fume events” which can leave pilots disorientated.

She said it would take a catastrophic air crash for the industry to act.

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Dr Michaelis, of Stirling University’s Occupational and Environmental Health Research group, is among the speakers at a major four-day conference on aircraft cabin air in London, starting tomorrow [Tues].

She will argue that cabin air safety falls into a “gap” between the Civil Aviation Authority (CAA), which regulates air traffic, and the Health and Safety Executive (HSE) which enforces occupational health.

She said: “It’s for the CAA to take the lead on hazardous substances on aircraft, but the CAA does not have expertise in this area. The HSE does but they don’t get involved - they leave it to the CAA.

“In other words, the protections that are there under the occupational health and safety regulations in Europe are not being applied to the aircraft contaminated air problem: that is, oil and fluids leaking into the aircraft breathing air supply. They [the CAA] just turn a blind eye.”

Her comments come as EasyJet announced it will fit filters to stop toxic fumes entering its passenger cabins and cockpits.

The airline told the Sunday Times that "health concerns" had led it to begin work with an aerospace company to develop a new system.

It is thought to be the first time that an airline has acknowledged the potential risk of "aerotoxic syndrome", which could also affect frequent flyers.

Ms Michaelis said that since the CAA was funded by airlines there was no incentive to tackle an issue which could leave them liable to compensation claims or redesign costs.

Ms Michaelis said: “The airline industry would need a major accident [to do anything about it].

“But you cannot have a cost-benefit analysis where you say ‘is it going to cost more to fix the problem than if we lost the aircraft with all the people on board?’ - that’s not acceptable.

"I’m sure the people that might be in some future accident would not agree that it’s acceptable to breathe contaminated air.

“It’s like sticking a pipe from your exhaust into your car and saying ‘what’s the problem?’ - it’s stupidity.”

Ms Michaelis worked as a commercial pilot in Australia until she was medically retired, aged 34, in 1997 after eventually becoming too ill to fly.

She has since specialised in researching the issue. In June, she was the lead author on the first in-depth study on the cabin air contamination, published in a World Health Organisation journal, which concluded that it was a “clear occupational and public health issue with direct flight-safety consequences”.

Ms Michaelis said: “Almost every flight I would get in the air, I would turn the air supply on, and that’s when I would start to get headaches, fatigue, nausea, difficulty concentrating, and airway irritation.

“Then when I got outside the aircraft I would recover. Once back inside the aircraft, I would go downhill.

"On several occasions the air was so bad that couldn’t stay flying the aircraft – I had to go and sit outside [the cockpit] to recover. I was effectively incapacitated.”

A spokesman for the CAA said: “Our priority is always the safety of passengers and crew and we continue to work with airlines, manufacturers and international regulators to drive improvements in safety standards across the industry.

"We understand the concerns that have been raised about cabin air quality and we take very seriously any suggestions that people have suffered ill health from flying.

“We rely on guidance from scientific experts based on the results of a number of independent studies and evidence reviews – including government commissioned research.

"Long-term ill health due to any toxic effect from cabin air is understood to be unlikely, although such a link cannot be ruled out.”

HeraldScotland:

Analysis: Pilot felt dizzy, nauseous and had tunnel vision as he landed plane

IT has been described as "big tobacco all over again". Critics say that just as the cigarette companies in the 1950s dodging a link between smoking and lung cancer, so airlines and the aviation authorities they fund are today loathe to own up to a problem with contaminated cabin air in case they find themselves saddled with costly redesigns and compensation claims from sickened employees.

The controversy relates to the use of "bleed-air" to pressurise and ventilate aircraft cabins and cockpit, which has been standard design on passenger jets since the 1950s. All commercial planes - with exception more recently of the Boeing 787 Dreamliner - use the bleed-air system, which means the air breathed by passengers and crew is contaminated by low-level concentrations of poisonous chemicals coming from the engines which have been linked to infertility, cancer and harm to unborn babies.

These include compounds called organophosphates, which have been blamed for causing various neurological symptoms such as numbness, memory loss, mobility problems, and headaches in thousands of pilots and cabin crew worldwide.

Dr Michaelis' own study, published in the WHO journal Public Health Panorama, found that in a sample of 274 UK-based pilots, 36 had either died or experienced chronic ill health leading to a permanent loss of fitness to fly, while a total of 172 reported some type of health problem. Diagnoses included chronic fatigue, gastrointestinal problems and neurological disorders.

The study also examined 15 so-called "fume events" - serious chemical leaks into the cockpit - which had occurred on flights in Australia, Germany, the UK and US. It found that a third of cases resulted in "full or partial incapacitation" of both pilots.

One notorious case in Germany in 2010 saw both the captain and co-pilot of a Germanwings plane overcome by fumes on approach to Cologne which left them nauseous, dizzy, suffering from tunnel vision, concentration problems and severe tingling.

By the time they put on oxygen masks and recovered some control, the plane was travelling too fast for an autopilot landing and the captain - despite feeling unwell - had to land the aircraft manually. Both pilots, who described feeling in a "dream-like" state during the landing, were subsequently signed off sick for six months.

However, recent research by the European Aviation Safety Authority (EASA) found that air quality on the flights it tested was similar or better than that observed in normal indoor environments, such as homes and hospitals. Critics insist that safe standards on the ground are not necessarily the same in a pressurised environment at altitude, where the chemicals have been heated.

The debate looks far from settled.