Your flight has been uneventful so far, and now lunch is being served. You look up into the eyes of your flight attendant. Her pupils are dilated. Her hands shake, and her speech is slurred. Is she on drugs?

Not likely. It's more probable that she's suffering from "skypoxia" -- something in the cabin air is making her look intoxicated and feel sick.

Many airlines address this problem by requiring random drug tests for crew. All the airlines insist that there is nothing in the cabin air that could be making flight attendants sick.

And pilot complaints are rare. But airlines provide separate, purer, oxygen-rich air on the flight deck, and this disparity in air quality between the cockpit and the cabin leads to a logical conclusion.

The problem is apparently complex. A number of environmental factors in the aircraft cabin are being blamed, including low oxygen in recycled air, low humidity that puts a strain on the respiratory tract, and pesticide residues from systematic sprayings.

Now a new problem is at the forefront of potential causes. Toxic chemical vapors originate from hydraulic spills--and the resulting cabin fumes are now being directly linked to incidents of flight attendant illnesses.

Thousands of compaints have been filed by Alaska Air flight attendants, who filed a class action lawsuit naming the hydraulic fluid Skydrol made by Monsanto.

"Vaporized hydraulic fluid is a known neurotoxin," says environmental health specialist George Ewing, M.D.

Dr. Ewing says he's been seeing poisoned flight attendants for over ten years. He reports, "One staggered off the plane like she had had a stroke, obviously suffering from acute neurotoxicity."

Dr. Ewing goes on to explain, "Flight attendants breathe significantly more oxygen than the passengers do because they are running up and down the aisles and pushing heavy carts. They also take in significantly more toxicity."

The problem actually involves many airlines and many types of aircraft. In Australia, flight attendants at Ansett Airlines blame leaky engine seals and Mobil Jet Oil, the engine lubricant, for their illnesses. The Australian TV show Insight did a feature on skypoxia, and reported that the Australian government is looking into this problem.

Toxic chemical fumes are sometimes accompanied by an acrid smell and smoke in the cabin. But a trip to any airport reveals diesel-smelling air. Jet fuel, also known as aviation gasoline or "av gas," is basically kerosene, a version of diesel.

And av gas is laced with pesticide additives to kill fungus, algae, and other microbes. Biobor, a fuel biocide made by Texas-based Hammonds, is used by many airlines to eliminate microorganisms in jet fuel. Longterm studies with animals exposed to Biobor show delayed effects such as decreases in sperm production and testicle size in males, and developmental anomalies in fetuses of females.

For humans, health problems related to toxic chemical poisoning are also often delayed. Low-level exposures result in burning eyes, nausea, headache, fatigue and flu-like symptoms. Within several hours of a "major event," symptoms may also include scaly, swollen, secreting eyes, nervous tremors, and memory loss. Immune and reproductive damage takes years, even generations, to uncover.

The airlines say they cannot find the cause for skypoxia. Further, without admitting culpability, they say expensive aircraft modifications have been made to resolve the problem.

As for the ill flight attendants, the airlines say the cause is not in the air. According to management, some people are just more sensitive to the smells encountered in everything from traffic to office buildings. When these individuals are exposed to something that they believe to be toxic, they get ill.

Toxicologist Professor Chris Winder at the University of New South Wales in Australia disagrees. He maintains that oil fumes are a hazardous substance, and further, the way in which fumes react with other chemicals synergistically may be at the bottom of the problem. Although very little is known about chemical synergy at this level, he believes the problem is very real because of the many ill flight attendants.

Fighting to prove long-term health effects is proving to be a tough battle for flight attendants. The courts are requiring a clear link between workplace injuries and illness. And access to illness reports of passengers and other crewmembers is restricted by the airlines, as is access to reports of chemical leaks and spills.

Further, the airlines vigorously fight claims for compensation. At my Hearing, trying to get Worker's Comp benefits from United Airlines, United hired an out-of-state expert witness, Houston, Texas, toxicologist Eric G. Comstock, M.D. He testified that it's impossible to be allergic to chemicals because the human body is made up of chemicals.

This nonsense was believable to the court, and I was denied all compensation for my loss of health and loss of employment.

Flight attendants, unlike other employees in the U.S., are not protected by OSHA (Occupational Safety & Health Administration). Instead, the FAA has full responsibility.

When asked to comment on the skypoxia problem, FAA spokesperson Mitch Barker stated that no one can find the cause for the flight attendant problems. He went on to say that aircraft modifications have been made, the planes are certified, maintenance procedures are approved, and the cabin is safe for passengers and crew.

The Air Transport Association, the aviation lobby group, refused to comment.

Flight attendants contend that chemical poisoning, also known as organophosphate poisoning, has been documented with airlines all over the world including Continental, Delta, American, TWA, US Airways, Air BC (Canada), China Airlines, and KLM.

However, even as more flight attendants become medically grounded, there seems to be an abundance of candidates waiting in the wings to take to the skies.

Perfect health is a worldwide requirement for flight attendant new hires. So, if all airline flight attendants are hired with near perfect health, what's going on? I know my health was perfect when I started flying.

The effect of toxins on humans is cumulative.

Sick airplanes have been reported for over a decade, but until now the business of flying has taken precedence. On a world map, dots indicating sick flight attendants appear on every continent. But nobody is monitoring the problem -- nobody seems to be connecting the dots to expose the catastrophic consequences of this problem.

FROM READERS

"For more years than most people can remember, Skydrol hydraulic fluid has been known as a deadly toxic substance that will eat up the fabric of mechanics coveralls. The fumes, vaporised or aerosol, are deadly toxic, and as far as I know there is no treatment or antidote for Skydrol poisoning. The same holds true for turbine oil, although in the last few years the vendors have reformulated turbine oil, to reduce its toxic effects, after many older mechanics came down with mysterious ailments, after long exposure to turbine oil on their hands."--Frank Szymanski

"In your article on Skypoxia you mention that jet fuel is the same as av-gas. This is not true. Av-gas is what is used in piston engine aircraft. Kerosene is what is used in jet engines. These fuels are quite different in how they are manufactured and what they contain. You are right in saying that there are additives to prevent microbial growth in jet fuel. Kerosene has a tendency to attract moisture and therefore is subject to the growth of a jelly like substance that will clog fuel filters. This is not the case in av-gas, which is refined like gasoline. Besides operating my own aircraft maintenance business, I teach aircraft maintenance."-- Gary Hillman, Aircraft Maintenance Engineer

"Thanks!!! Great article, Diana! I fly a lot less since becoming chemically sensitive in a sick house incident, but when flying I find that a doctor's mask rated for viruses helps a great deal. This implies that there's something in the air which is either an ultrafine dust or dissolved in the moisture in the air, since VOCs (including pesticides) pass through such a mask. The fact that cabin air passes near both hydraulic fluid and av gas is an interesting clue, but I bet when this is finally understood the basic problem will turn out to be something like ubiquitous atmospheric sulfates being reduced to sulfites by reaction with some VOC all the fabric surfaces in the plane offgas (those sulfites disrupt oxygen metabolism in the bloodstream), exacerbated by all of the things we can now identify (pesticides, hydraulic fluid and av gas, passengers wearing perfume, etc). Perhaps a protocol allowing flight attendants to use first aid oxygen at the first sign of "skypoxia" is in order! This would do two things: first, stop the inhaled exposure to let the body recover a bit, and second, overcome the hypoxia caused by whatever's in the air messing with oxygen metabolism. Of course I'm dreaming, if the airlines allowed such a practice they'd be admitting cabin air wasn't perfect." --Steve Chalmers

"Thanks for sharing the tips about air in planes. I have chemical sensitivities resulting from a workplace exposure to formaldehyde which have greatly limited what I can do and where I can go. I did not realize that the pilot could improve the air on request. I look forward to your book on chemical poisoning when it is published."-Cindy