Aerotoxic syndrome
Encyclopedia
Aerotoxic syndrome is a term describing the alleged short-term and long-term ill-health effects that are attributed to exposure to cabin air
Cabin pressurization
Cabin pressurization is the pumping of compressed air into an aircraft cabin to maintain a safe and comfortable environment for crew and passengers when flying at altitude.-Need for cabin pressurization:...

 that has been contaminated with atomized engine oils and other chemicals. The documentary film Welcome Aboard Toxic Airlines
Welcome Aboard Toxic Airlines
Welcome Aboard Toxic Airlines is a 2007 British investigative documentary film directed and produced by former airline captain Tristan Loraine on the subject of so-called aerotoxic syndrome.-Plot:...

 suggests the term was first suggested in 1999 by members of an electronic global ‘egroup’ called Aerotox. Members of this group, included Dr Harry Hoffman, a former US Navy Flight Surgeon, Professor Chris Winder, a toxicologist at UNSW in Sydney and Dr Jean Christophe Balouet a French Environmental forensics expert.

With the exception of the new Boeing 787 and the retired Concorde
Concorde
Aérospatiale-BAC Concorde was a turbojet-powered supersonic passenger airliner, a supersonic transport . It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation...

, the air in a jet or turboprop aircraft cabin is typically supplied by bleed air
Bleed air
Bleed air in gas turbine engines is compressed air taken from within the engine, after the compressor stage and before the fuel is injected in the burners. While in theory bleed air could be drawn in any gas turbine engine, its usage is generally restricted to jet engines used in aircraft...

 from the aircraft’s engines. Several Pilot and Flight attendant Unions alongside with expert groups have claimed that aircrew and passengers have been made ill by toxins in engine oil that can enter the air supply.

As of 2009 this syndrome is not officially recognized in aviation medicine
Aviation medicine
Aviation medicine, also called flight medicine or aerospace medicine, is a preventive or occupational medicine in which the patients/subjects are pilots, aircrews, or persons involved in spaceflight...

. The term was used by a year long Australian Senate Investigation that concluded in 2000, that inhaling heated engine oils fumes was a risk to health and flight safety.

Potential sources of contamination

Modern jetliners have an Environmental Control System
Environmental Control System
The environmental control system of an aircraft provides air supply, thermal control and cabin pressurization for the crew and passengers...

 (ECS) that manages cabin air. Some of the air is recirculated, while the remainder is drawn from the outside, typically via compressed engine bleed air
Bleed air
Bleed air in gas turbine engines is compressed air taken from within the engine, after the compressor stage and before the fuel is injected in the burners. While in theory bleed air could be drawn in any gas turbine engine, its usage is generally restricted to jet engines used in aircraft...

. Airborne contaminants may potentially originate from substances used in the maintenance and treatment of aircraft, including seasonal chemicals such as de-icing
Deicing
For snow and ice control on roadways and similar facilities, see Snow removalDe-icing is defined as removal of snow, ice or frost from a surface...

 fluids, or from the ECS systems.

A service information leaflet from the UK-based Committee on Toxicology (COT) provided a list of possible sources of poor quality cabin air. Some of the items on that list include:
  • Underfloor hydraulic leaks.
  • Ingestion of deicing fluid
    Deicing fluid
    Ground deicing of aircraft is commonly performed in both commercial and general aviation. The fluid used in this operation is called de-icing or deicing fluid...

     into APU inlet.
  • Periodic maintenance task that is required to clean the forward galley oven.
  • Inappropriate or excessive use of CO2
    Carbon dioxide
    Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

     (dry ice
    Dry ice
    Dry ice, sometimes referred to as "Cardice" or as "card ice" , is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue...

    ) by caterers.
  • Toilet fluid spillage, leakage and also unapproved mixing of different disinfectant fluids within the toilet.
  • Leakage of the rain repellent system, or rain repellent contamination within the cabin or flightdeck.
  • Spillage within baggage bays.
  • Items stowed in overhead baggage bins.

Jet engines require synthetic oil
Synthetic oil
Synthetic oil is a lubricant consisting of chemical compounds that are artificially made . Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials...

s for lubrication. These oils contain ingredients such as tricresyl phosphate
Tricresyl phosphate
Tricresyl phosphate, abbreviated TCP, is an organophosphate compound that is used as a plasticizer and diverse other applications. It is a colourless, viscous liquid, although commercial samples are typically yellow...

 (TCP), an organophosphate
Organophosphate
An organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...

, that could possibly be toxic to humans in large quantities. Engine bearing seals are installed for the purpose of ensuring that critical engine bearings are continuously lubricated, and also to prevent engine oil from leaking into the compressed air stream. If a bearing seal fails and begins to leak, depending on the location of the seal, some amount of engine oil may be released into the compressed air stream. Oil leaks may be detected by odour, or in more serious cases, by smoke in the cabin. This is known in the industry as a “fume event”. Although most jet aircraft cabins have filters for the recirculated cabin air, the bleed air
Bleed air
Bleed air in gas turbine engines is compressed air taken from within the engine, after the compressor stage and before the fuel is injected in the burners. While in theory bleed air could be drawn in any gas turbine engine, its usage is generally restricted to jet engines used in aircraft...

 supply is not filtered.

In a flight safety bulletin to all operators, dated January 5, 2001, BAE Systems included the following information:

Incidents and symptoms

According to Dr. S. Michaelis, crews have been impaired or incapacitated in flight on a number of occasions, following exposure to fumes during flight.

On 5 November 2000, both the pilot and co-pilot of a Jersey European Airways BAe 146
BAe 146
The British Aerospace 146 is a medium-sized commercial airliner formerly manufactured in the United Kingdom by British Aerospace, later part of BAE Systems. Production ran from 1983 until 2002. Manufacture of an improved version known as the Avro RJ began in 1992...

 became unwell while landing at Birmingham International Airport, with both becoming nauseous, and the pilot experiencing double vision and having difficulty judging height. Despite this, he managed to land the aircraft safely. "The first officer and commander were taken to hospital and examined,
but no abnormalities were found."
The subsequent incident investigation report concluded that "There is circumstantial evidence to suggest that the flight crew on G–JEAK were affected by contamination of the air supply, as a result of oil leakage from the auxiliary power unit
Auxiliary power unit
An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...

 (APU) cooling fan seal into the APU air stream, and into the ECS system ducting. This contamination allowed fumes to develop, a proportion of which entered the cabin and cockpit air supply."

That same AAIB Report also noted that both the captain and the first officer had visited the forward toilet, before the onset of their symptoms. About the same time of the G-JEAK incident, another operator reported overuse of a disinfectant (formaldehyde) for the toilets and to clean the galley floor and then inhalation of the fumes from that chemical, would produce the identical symptoms reported by both the captain and first officer of G-JEAK. "The CAA notified UK Operators at that time (CAA ref. 10A/380/15, dated 2 August 1996) of this potential hazard, as the misuse of this agent was apparently widespread."

The alleged ill-health effects that have been reported include cognitive problems, dizziness, disorientation, nausea, breathing difficulties, anxiety, mood swings, malaise, diarrhoea and various other neurological problems, particularly related to the autonomic nervous system
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...

. Chronic fatigue syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is the most common name used to designate a significantly debilitating medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially...

 (CFS) and Multiple chemical sensitivity
Multiple chemical sensitivity
Multiple chemical sensitivity is a chronic medical condition characterized by symptoms the affected person attributes to exposure to low levels of chemicals. Commonly suspected substances include smoke, pesticides, plastics, synthetic fabrics, scented products, petroleum products and paints...

 (MCS) are also commonly reported by sufferers. UK government research states that adverse health effects of short duration do occur, but although it cannot rule it out, says that the available evidence is unable to conclude a link to long-term symptoms.

Lobbying groups

Aviation Organophosphate Information Site (AOPIS) is a non-profit group set up by airline crews in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 in 2001. AOPIS provides campaigns and information by way of articles, scientific papers, research papers, governmental policy and a documentary, on medical and flight safety issues relating to contaminated air exposure on commercial and military aircraft.

The Global Cabin Air Quality Executive (GCAQE) is a global coalition of health and safety advocates committed to raising awareness and finding solutions to poor air quality in aircraft and was established in 2006 by a number of unions such as the Independent Pilots Association (UK), Unite the Union
Unite the Union
Unite – the Union, known as Unite, is a British and Irish trade union, formed on 1 May 2007, by the merger of Amicus and the Transport and General Workers' Union...

, Australian and International Pilots Association
Australian and International Pilots Association
The Australian and International Pilots Association is a trade union and professional association formed in 1981 to represent Qantas and its related companies pilots and flight engineers. The AIPA broke away from the Australian Federation of Air Pilots in the early 1980s...

, Association of Flight Attendants
Association of Flight Attendants
The Association of Flight Attendants-CWA is a union representing Flight Attendants in the United States. In 2011, AFA represents nearly 60,000 Flight Attendants at 24 airlines, making it the world's largest Flight Attendant union. Focused 100% on Flight Attendant issues, AFA has been the leader in...

, Canadian Union of Public Employees
Canadian Union of Public Employees
The Canadian Union of Public Employees is a Canadian trade union serving the public sector - although it has in recent years organized workplaces in the non-profit and para-public sector as well...

 and others.

Lastly, the Aerotoxic Association
Aerotoxic Association
The Aerotoxic Association was set up on 18 June 2007 at the British Houses of Parliament by Captain John Hoyte. The association is run by a group of airline pilots who believe they were made ill by the cabin air on jet aircraft, with the assumption that the bleed air was contaminated with engine oil...

 was set up on 18 June 2007. The association is run by a group of airline pilots who believe they were made ill by contaminated cabin air.

Research

In 1986, the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 commissioned a report by the National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...

 (NRC) into cabin air quality. The landmark report recommended a ban on smoking on aircraft in order to improve air quality, which was brought into effect by the FAA soon after.

However little research took place into cabin air quality in the following 15 years, despite ongoing concerns raised by passengers and crew. In 2000, Congress responded by once again directing the NRC to conduct an independent study into cabin air quality, and to make recommendations for improvements.

Ongoing research commissioned by the UK government's Department for Transport
Department for Transport
In the United Kingdom, the Department for Transport is the government department responsible for the English transport network and a limited number of transport matters in Scotland, Wales and Northern Ireland which are not devolved...

 (DfT) has not managed to conclude a link to long term health. In its response to the many complaints received "from a number of witnesses, particularly the Organophosphate Information Network, BALPA, and the International Association of Flight Attendants, expressing concerns about the risk of TOCP poisoning for cabin occupants, particularly for crew who might be subjected to repeated exposure in some aircraft types, as a result of oil leaking into the cabin air supply," the UK Parliament's Select Committee on Science and Technology, concluded:
"This question - including the potential effects on aircrew from any long-term exposure - has been looked at in much greater detail by a Committee of the Australian Senate inquiring into particular allegations of such contamination in the BAe 146. Although its Report[58] referred extensively to cabin air quality and chemical contamination in the aircraft, and recommended that the engine lubricating oil used (a Mobil product) be subjected to a further hazardous chemical review, it made no specific points about TCP or TOCP that have given us additional concerns[59]. The absence of confirmed cases of TOCP poisoning from cabin air and the very low levels of TOCP that would be found in even the highly unlikely worst case of contamination from oil leaking into the air supply lead us to conclude that the concerns about significant risk to the health of airline passengers and crew are not substantiated."


According to a report by former British Airways
British Airways
British Airways is the flag carrier airline of the United Kingdom, based in Waterside, near its main hub at London Heathrow Airport. British Airways is the largest airline in the UK based on fleet size, international flights and international destinations...

 Head Doctor, Prof Michael Bagshaw, there have been no peer-reviewed recorded cases of neurological harm in humans following TCP exposure. He points to an unpublished report from the Medical Toxicology Unit at Guy's Hospital
Guy's Hospital
Guy's Hospital is a large NHS hospital in the borough of Southwark in south east London, England. It is administratively a part of Guy's and St Thomas' NHS Foundation Trust. It is a large teaching hospital and is home to the King's College London School of Medicine...

 in 2001 which looked at all exposures dating back to 1943 that showed that all documented exposures are to high concentrations greatly in excess of the amount present in jet oil.

According to Dr. S. Michaelis, TCP has been detected in aircraft cabins during numerous air and swab sampling tests.

Media coverage

In a 2006 article in Aviation Week
Aviation Week & Space Technology
Aviation Week & Space Technology, often abbreviated Aviation Week or AW&ST, is a weekly magazine owned and published by McGraw-Hill...

, Dr. Simon BennettDr. Bennett is director of the Scarman Centre's distance-learning MSc in Risk, Crisis and Disaster Management, with a PhD in sociology from Brunel University, London. found that media coverage of contaminated cabin air has been sensationalized, with distortions of facts. He cited headlines such as "You are being gassed when you travel by air," and "Death in the Air" and a sub-title of "Every day, planes flying in and out of London City Airport
London City Airport
London City Airport is a single-runway airport. It principally serves the financial district of London and is located on a former Docklands site, east of the City of London, opposite the London Regatta Centre, in the London Borough of Newham in east London. It was developed by the engineering...

 are slowly killing us." Dr. Bennett noted that the article with the latter subtitle stated in its body that the Department of the Environment, Transport and the Regions (DETR) found that oil seal failures occur only once in every 22,000 flights. Similarly, the Sunday Sun
Sunday Sun
The Sunday Sun is a regional Sunday newspaper in North East England, Cumbria and the Scottish Borders, published in Newcastle Upon Tyne by Trinity Mirror...

 in an article entitled "Flight Fumes Warning", cited the industry pressure group AOPIS in saying that passengers jetting off to their holidays were unknowingly exposed to deadly chemicals, and that brain damage could result if they breathed the toxic fumes. However the Sun too admitted that the UK Civil Aviation Authority found that leakage into aircraft cabins is a very rare event that occurs only if there's a fault with an aircraft.

He found that when Sarah Mackenzie Ross submitted the results in 2006 of a clinical audit of the "cognitive functioning of aircrew exposed to contaminated air" to the UK government's Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT), some media used it to write articles that were sensational and misleading.

The Dagbladet
Dagbladet
Dagbladet is Norway's second largest tabloid newspaper, and the third largest newspaper overall with a circulation of 105,255 copies in 2009, 18,128 papers less than in 2008. The editor in chief is Lars Helle....

.no, a Scandinavian news-based Internet site, wrote that the Ross report "... adds weight to the hypothesis that compounds resembling nerve gas in cabin and flight deck air have caused irreparable neurological damage to aircrew." That, despite the fact that:
  • The report was a "clinical audit of aircrew seen for clinical purposes," and was not a valid research study.
  • The "'aircrew seen for clinical purposes' were in fact a self-selecting sample of pilots." Meaning that they all came from a group that already believed they had been damaged by contaminated air.
  • That self-selected sample group "was not compared to a control group."
  • Ross herself said "The conclusions that can be drawn from these findings have limitations."
  • She further stated: "The author ... makes no attempt to ascribe causality."
  • The report's conclusions were ambiguous: "There was no evidence of ... intellectual decline, language or perceptual deficits .... Indeed pilots were intact on the vast majority of tests. However, there was evidence of under- functioning on tests associated with psychomotor speed, executive functioning and attention ...."
  • And finally, "[T]he evidence available to us in this audit does not enable us to draw firm conclusions regarding a causal link with exposure to contaminated air."


The most prominent feature of Dagbladet.nos reporting was its sensationalism. One article used the banner headline: "You are being gassed when you travel by air." That implied that cabin air is contaminated on a routine basis, but, that is not true. In another article, the Dagbladet.no contradicted itself: "When asked by Dagbladet.no for information, the Norwegian Civil Aviation Authority's analysis section ... revealed 13 mysterious incidents which may be connected with contaminated cabin air in aircraft [between 2001 and 2005]." Dr. Bennett asked, "...how a report that was careful not to ascribe causality could be seen to support the hypothesis that organophosphates in flight-deck and cabin bleed air cause neurological damage among aircrew?"

The Times also reported on Dr. Bennett's research into flight crew fatigue and stress. Dr. Bennett commented on that article: "Despite its positioning as a 'quality' newspaper, The Times produced a determinedly skewed account of the research. Important facts—like the limitations of the research methodology (the research paper was based on interviews with just 11 pilots)—were not mentioned by The Times."

Several documentary films have been made on the Aerotoxic Syndrome issue including: "Contaminated Air - An Ongoing Health and Safety Issue" [2003], "Welcome Aboard Toxic Airlines" [2007], "Angel Without Wings" [2011] and "Broken Wings' [2011]. A feature film is also in the making entitled "Shadows From The Sky".

Legal Precedents

The legal precedent that inhaling oil fumes is harmful was set in the High Court of Australia on the 5 May 2009, in the case Joanne Turner v. Eastwest Airlines. The Australian courts found in favour of Ms. Joanne Turner in her case for compensation against her former employers for injuries resulting from exposure to heated jet engine oils. Ms
Turner a former flight attendant with Australia’s Ansett and Eastwest Airlines, was exposed to smoke and fumes resulting from a failed oil seal on a BAe 146 flight between Sydney and Brisbane on 4 March 1992, whilst 5 months pregnant.
The court found that Ms Turner was exposed to oil fumes and smoke generated from engine oil that had leaked into a component of the aircraft air supply system called the Auxiliary Power Unit (APU - engine).
The failure of the APU oil seal was found to be foreseeable, as was the risk that smoke from the leaking oil would enter the aircraft cabin.
The judge found that: “The plaintiff was exposed to pyrolysed Mobil Jet Oil II on 4 March 1992” and “that pyrolysed effects of Mobil Jet Oil II are harmful to the lungs.”
The defendant appealed the decision to the New South Wales Court of Appeal and then the High Court of Australia, however subsequently lost both appeals on 1 April 2010 and 3 September 2010 respectively.

In 2011, a former flight attendant is believed to be the first person in the U.S. to settle a lawsuit against the Boeing Co. over what she claimed was faulty aircraft design that allowed toxic fumes to reach the cabin, triggering tremors, memory loss and severe headaches.

The amount and other details of the settlement Wednesday between former American Airlines worker Terry Williams, a 42-year-old mother of two, and Boeing were not made public as a condition of the agreement.

External links

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