WASHINGTON, D.C. - When you get on a plane, you see the flight attendants, the passengers, even the bags getting on board.
What you don’t see is something else that might be sneaking into your cabin.
“Everyone was getting sick from First Class all the way to the back. People were vomiting.”
In 2000, flight attendant Ruth Medina says she was working on a 747 headed to Japan when, four hours into the flight, she says nearly everyone became ill.
“By that time, I had been flying for 28 years,” Medina says. “So, I had never witnessed anything like this before.”
Medina says she felt nauseous for the next 24 hours before she and her crewmates boarded the same plane to head back to the United States.
“The same thing happened,” Medina says. “Four hours into the flight, the entire aircraft was ill again. People were vomiting and they were just sick.”
This time, Medina says she also got sick and now, nine years later, she says she’s still dealing with confusion and other neurological problems. She is now one of several flight attendants who sued airlines saying they were exposed to toxic chemicals in the cabin’s air supply.
"There are chemicals that are in hydraulic fluid or jet fuel that can get brought into the air of the aircraft," says University of California San Francisco Occupational Medicine Specialist Dr. Robert Harrison.
Harrison says Medina was exposed to toxic chemicals in the plane’s “bleed air,” outside air that comes through the engines into the air conditioning system.
He explains that, "This problem occurs when the mechanical system of the aircraft malfunctions and these products, when they're burned, get into the air supply system and are circulated around the cabin air.”
The contaminated air, Harrison says, is similar to what you would find in dangerous pesticides and can lead to temporary symptoms that may be confused with jet lag. Sometimes, he says, the symptoms can develop into more chronic neurological problems like headaches, dizziness, loss of memory and concentration.
"The name for it is Aerotoxic Syndrome," Harrison says.
Aerospace Medical Association Executive Director Russell Raymond disagrees.
"That term has been discredited,” Raymond says. “It implies the airliner cabin is unhealthful and there are toxic substances in the cabin. That is not true."
Raymond’s group is made up of doctors and scientists who study medical problems with air travel, including bleed air. He says most airplanes use filters and the air inside a plane is actually cleaner than most people’s homes. "There are sometimes events in flights, but I think they are very, very rare and very unusual."
The Federal Aviation Administration says when toxins do get into the air supply; it’s called a “fume event” and must be reported to the FAA.
The FAA says there have only been 900 of these fume events in the last 10 years.
Others argue it’s more common. “We estimate that this happens approximately once every 4-5,000 flights,” Harrison says.
But former commercial pilot Captain John Hoyte says you probably wouldn’t even know about it because the airlines don’t have to tell you if you’ve been exposed.
"It’s a very well kept secret what's going on here,” Hoyte says. “I think most people wouldn't actually understand what was affecting them at the time. That was the case with me. I only found out about it a year after I stopped flying."
After more than 30 years in the air, Hoyte says he began to have memory and speech problems so severe, he was forced to quit. “One flight in 2002, the whole passenger cabin filled with white fumes.”
To push the airlines into using different air supplies, Hoyte started a website devoted to Aerotoxic Syndrome (
Aerotoxic Assiociation - Support for sufferers of Aerotoxic Syndrome).
Ruth Medina says she still gets so disoriented, she gets lost in the same neighborhood she grew up in. “I got confused and couldn’t find my way home.”
The FAA says it takes these kinds of complaints seriously and has scientists working on a device that could test for toxins inside airplanes. But it could take years to develop the technology.
Leaving millions of passengers to wonder if they feel sick because of jet lag or because of something else floating in the air.