Airplane pilots are responsible for controlling large machines and keeping people safe every day.
Yet exposure to toxic chemicals on their airplanes may impair their ability to perform these tasks, University professor Steve Hecker said.
Two research groups, one headed by University researchers and one headed by the Harvard School of Public Health, have received a nearly $2 million Federal Aviation Administration grant to investigate how toxic chemicals affect pilots and flight attendants.
Hecker, an associate professor at the University’s Labor Education Research Center and director of the center’s occupational health and safety programs, said a 2002 report by the National Academy of Sciences inspired the U.S Congress to direct the FAA to perform research on aircraft air quality.
William Nazaroff, a member of the committee that produced the report, said in a 2003 statement before the U.S. Congress that people inside airplanes can be exposed to contaminants, including ozone, even when the environmental control system is operating normally. When the system is broken, passengers may be exposed to engine oils, hydraulic fluids and deicing fluids.
Nazaroff’s statement said the committee recommended research into the health effects of ozone, the effect of cabin-pressure altitude, toxicity of engine fluids, pesticide exposure in airplanes and low relative humidity.
Hecker’s team is conducting a survey of pilots and flight attendants to determine how commonly and severely they experience health symptoms attributed to aircraft chemicals.
The team is currently working with the British Air Line Pilot’s Association and the Association of Flight Attendants.
Members of Hecker’s team plan to collect air samples while onboard commercial airliners. However, because incidents of chemical leakage happen relatively infrequently, Hecker said, flight attendants participating in the study will be trained to collect air samples if they see smoke or smell fumes on flights.
The air that airplane passengers breathe enters the cabin through the engine, where it is compressed and treated. Normally this is safe because engine fuel and hydraulic fluids are separated from the air stream, but sometimes internal seals leak, contaminating the air with the engine fluids. These fluids, Hecker said, contain additives from the organophosphate chemical family. When inhaled, organophosphates affect the central nervous system and peripheral nervous system.
Hecker said incidents of leakage are not common but are potentially severe when they do happen, adding that some near-crashes and the August crash of a jet in Greece are suspected to have been influenced by chemical leaks.
“You get reports and anecdotes like this, but no one has ever done a systematic scientific study,” Hecker said.
Judith Murawski, industrial hygienist for the Association of Flight Attendants, said she spends about half her time on the job dealing with reports of health issues caused by airplane chemicals. She is currently handling the cases of three flight attendants who worked on an Oct. 8 flight from Philadelphia to Fort Lauderdale, Fla., in which engine oil leaked into the air supply. The flight attendants now suffer from tingling of the arms and feet, fatigue, muscle aches and extreme confusion.
Murawski said estimates of the frequency of air quality incidents on passenger flights range from one in 250 flights to one in 100,000 flights. The lack of an organized study leaves researchers unable to pin down a more accurate number.
“It’s my opinion that the airlines don’t want to have to collect the data systematically because they don’t want to have to do anything about it,” Murawski said.
Murawski said that while flight attendants are at greater risk than passengers for adverse effects from airplane chemicals because they move around the cabin more, it would be surprising if passengers didn’t also have health problems after in-flight chemical incidents.
However, if a passenger does get sick from airplane chemicals, Murawski said, the cause may not be identified because passengers and their doctors are not informed about the issue.
“It’s bad enough for the crew members, but the passengers are even worse off because they don’t have a union,” Murawski said, adding that airlines don’t provide maintenance records for their airplanes or follow up with passengers who were on flights with chemical incidents.
“It’s very important that the FAA is finally stepping up to the plate and funding this research,” Murawski said.

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