Aerotoxic syndrome is the term for the illness caused by exposure to contaminated air in jet aircraft. The use of bleed air from the engines as a component of cabin ventilation air can carry toxic vapours into the passenger cabin – referred to as a “fume event” (“Wet seals” are intended to keep oil and air apart but these seals can wear out and become less effective over time.) Frequent fume events, a particular hazard for aircraft crew and frequent flyers, cause chronic low-level exposure to residual toxins, including carcinogenic organophosphates and other volatile organic compounds and are associated with chronic or acute symptoms: violent vomiting, severe migraines, inflamed nerve endings in the brain, blurred vision, respiratory distress and heart spasms. Those afflicted by chronic aerotoxic syndrome can die of sudden cardiac arrest because toxins have moved into heart tissues, causing lymphocytic myocarditis – a deadly inflammation of the heart muscle caused by neurotoxins. Equally dangerous, especially in regards to aircraft crew, are the disorientation, feelings of intoxication and deficits in cognitive brain function that can accompany chronic aerotoxic syndrome. The existence of these symptoms raises the possibility of pilots who could become impaired and incapacitated during a flight.
Aerotoxic syndrome was discovered and named by French scientist Dr. Jean-Cristophe Balouet on 20 October 1999. The problem dates back to 1963, when aircraft moved from a fresh air source – air drawn from separate fuselage intake valves – to the use of “bleed air” direct from the engines, which is mixed with recirculated cabin air at a 50/50 ratio. Synthetic lubricant oil used by jets contains organophosphates (used in pesticides and nerve gas and banned by the EPA for residential use in 2001 because of known toxicity). The byproducts of these carcinogenic organophosphates can include aldehydes and carbon monoxide. If the wet seals fail suddenly, oil vapors get into the bleed air, causing fumes to enter the cabin. Many have likened the odour of a fume event, sometimes accompanied by a bluish smoke, to “dirty socks” and an “oily, chemical smell” In 1978 during deregulation, wet seal maintenance replacements were extended from 5,000 flight miles to 30,000 flight miles – a policy that endangers the health of passengers and crew.
Aerotoxic syndrome is believed to affect 250,000 pilots, cabin crew and passengers worldwide.
Currently, all airlines and practically all aircraft are susceptible to fume events. But frequency estimates vary, depending on who is doing the tabulating. There are currently no chemical sensors onboard aircraft to detect fume events, only the senses and perceptions of the crew and passengers. However, swab-testing can confirm fume events after the fact by detecting residues on interior surfaces of the cabin. According to the 2007 claim by the UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment, fume events occur in 1 in 100 flights. Clean cabin air activists, noting that toxic residue was found in 50 percent of all aircraft sampled, place the estimate at up to 50 percent of all flights – meaning hundreds of fume events occur worldwide on a daily basis.
Aerotoxic Association (AA) was founded by airline crew whose careers have been cut short by aerotoxic syndrome and to support similarly affected crew and passengers, inform the public of the dangers, and work with the industry to implement solutions. The association gathers, records and publishes accounts and photographs of fume events on aircraft around the world.
In 2010, a US Senator introduced Cabin Air Quality bill in the USA., with the placement of mandatory chemical sensors on all current bleed air aircraft and a return to the safer, pre-1979 policy of a 5,000 flight mile engine wet seal replacement window. The Bill would also require that all future aircraft utilize the safer “non-bleed air” design, as with the new Boeing 787 Dreamliner, which uses air directly from the atmosphere
A lawsuit was filed against Boeing by a Washington state flight attendant regarding a particularly noxious fume event in which the flight attendants, cabin crew and passengers smelled an odd odour, then developed severe headache, tingling fingers and disorientation. Some attendants reported vomiting and burning eyes, and a passenger passed out. The entire crew was evaluated by paramedics in Austin, Texas, and one flight attendant had to be treated at an area hospital for carbon monoxide poisoning.