Aerotoxic Syndrome

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The term aerotoxic syndrome is used to discuss possible damage to health that can be caused by contamination of the air in the cabin of passenger aircraft . Problems in the bleed air system are mainly cited as a possible cause of contamination of the breathing air. Airlines and aircraft manufacturers as well as authorities are now talking about so-called "fume events" or "smell events". It is important, however, that visible haze or smoke does not necessarily have to appear in the cockpit and aircraft cabin for every such incident.

Aerotoxic syndrome is considered a relatively unexplored clinical picture that is currently being investigated, although it has been known since the late 1950s. The term dates back to 1999 and was introduced by the American aviation doctor Harry Hoffman († 2004), the Australian toxicologist Chris Winder († 2014) and the French forensic scientist Jean Christophe Balouet .

Symptoms

The term “aerotoxic syndrome” summarizes a number of symptoms that occur in those affected after a so-called “fume event” and that are clinically detectable. These include: irritation of the mucous membranes, shortness of breath , cardiac arrhythmias , headaches , abdominal cramps, muscle weakness , flu-like symptoms, panic attacks, disorders of balance and gait, tingling and numbness. These symptoms may or may not appear immediately. They can also develop over days and weeks, or they can not occur at all. It has not yet been recognized as an official clinical picture. It is said to be caused by the ingestion through inhalation and through the skin of heated ( pyrolysed ) substances from the lubricants and hydraulic fluids used in aviation.

background

Virtually all commercial aircraft reflect the fresh air for the cabin by means of a bleed air system from the compressor of the engine . Initially it was assumed that only if the bearings in the compressor were not sealed properly would oil particles be pyrolyzed and then enter the airflow of the engine as vapors and from there via the bleed air system into the cabin air. However, engine manufacturers have now also recognized that there is no such thing as a completely oil-tight engine. Particularly during load changes, oil can escape from the seals inside the engine and heat up in the hot air flow (pyrolysis). According to the British aeronautical engineer Graeme Davidson, the leakage of small amounts of oil is also favored by the fact that engines are now operated longer between maintenance intervals than was the case, for example, in the 1980s. This procedure is tolerated by the supervisory authorities as long as the engines are constantly "monitored", i.e. the performance data are monitored.

Engine oils

The engines are lubricated with a special oil , which, however, when heated, produces highly toxic and nerve-damaging vapors, which under certain circumstances can get into the air in the passenger cabin unfiltered. These contain substances such as phenyl - naphthylamines and organophosphates , including tricresyl phosphate (TCP, Eng .: TCP), by several toxicologists were classified as highly dangerous. In an investigation of samples secretly taken in the machines of various airlines (mainly German companies) in 2008, residues of tricresyl phosphate were found in 90 percent of the samples. The highest value of 154.9 micrograms of tricresyl phosphate was applied to an area of 2 x 2 cm in a machine of the type Boeing 757 of Condor measured. In other machines, too, such as the BAe 146 or Avro RJ and Airbus, increased residues of TCP were registered in the cabin. But according to leading scientists such as the US pharmacologist and neurobiologist Professor Dr. Mohamed B. Abou-Donia is not the TKP, or its component triorthocresyl phosphate (ToKP), which is known to be toxic, is the cause of the symptoms and diseases. Rather, the scientist assumes that only the chemical “cocktail” of the various heated and thus modified substances leads to damage to the human organism. In his research on aerotoxic syndrome, Abou-Donia also refers to the findings that he and his colleagues gained at the time on behalf of the US Department of Defense regarding the health impairments in American and British war veterans, which are now recognized as Gulf War syndrome . Before their deployment in Iraq in 1991, the soldiers had been treated “preventively” with a large number of chemicals and preparations, including organophosphates. At that time it was found that although the individual substances were considered harmless, the administration of several of these substances, including organophosphates, could even lead to the death of the test animals in the laboratory.

According to an EASA study published in March 2017, the two new oils and used oils analyzed therein contain TCP, but no toxic orthotricresyl phosphate isomers were detected. According to the study, neuroactive substances are present in the oils after pyrolysis, but in such a low concentration that they cannot cause damage to a healthy lung. In a second study, small amounts of tricresyl phosphate concentrations in the nanogram range per cubic meter were measured on 69 scheduled flights with eight different aircraft and engine types, but never orthotricresyl phosphate. The air measurements in the Dreamliner (the Boeing 787 does not use bleed air) surprisingly revealed a similar pollutant concentration (including TCP) in the cabin as in the other aircraft types. The measured cabin air quality was similar or better than that in normal indoor spaces, e.g. B. in offices or schools.

Blood test (aka "Nebraska Test")

Small amounts of CPM could also be detected in the blood of passengers via a degradation product. This test, which was part of a research project at the University of Nebraska at the time , has not been offered since 2013.

Other health-impairing substances

A study using urine samples from 332 flight attendants and pilots, which was carried out on behalf of the Institute for Prevention and Occupational Medicine of the German Social Accident Insurance at the IPA Institute in Bochum, did not find any breakdown substances of the ToKP, which is considered toxic. It was concluded from this that the reported health impairments could not be triggered by ToKP. However, the Würzburg toxicologist Dietrich Henschler had already shown in his studies on tricresyl phosphate at the end of the 1950s that if the toxic ortho content of TKP was reduced, the toxicity of the di- and mono-ortho isomers of TKP by 5-10 times can increase. Regardless of this, it was noteworthy that in all urine samples taken, significantly increased metabolite concentrations for the organophosphates TBP ( tributyl phosphate ), TCEP ( tris (2-chloroethyl) phosphate ) and TPP ( triphenyl phosphate ) were found compared to the general population. The conclusion of the authors of this study, which was carried out on behalf of and with the participation of the trade association for transport , is therefore also discussed as “questionable” among experts . According to the method used for this purpose, it was not possible to determine "whether the two isomers of cresyl phosphate are absorbed, metabolized and excreted with the urine" ... "Possible concentrations are below the detection limit of 1.0 μg / l and are therefore not to be recorded with the present method ".

filter

Filter systems for cleaning the cabin air have now been developed and approved by the authorities, but are generally not used in passenger planes. Such a system is currently only in use on BAe 146 / Avro Regional Jet planes at Swiss and on the Boeing 757 of the freight company DHL . In the case of larger machines, there are obviously problems with the required air flow rate in the passenger cabin.

Forensic-pathological examinations on deceased crew members

The Westgate case

The forensic-pathological examinations on the corpse of the British pilot Richard M. Westgate, who died in Amsterdam in December 2012, came to the conclusion in July 2014 that the creeping poisoning caused by sustained low doses of pyrolyzed organophosphates can lead to massive health impairments. Westgate had given his body to science before his death in order to gain more precise information about aerotoxic syndrome. In addition to the death of brain and nerve cells, evidence of lymphocytic myocarditis was found in the heart muscle tissue of the deceased . This is understood to mean damage to the heart muscle tissue (see Fig. Westgate Microscopy)

Westgate Microscopy t-lymphocytes

The researchers and scientists involved in the investigations attribute this damage to the long-term exposure to pyrolysed organophosphates from the air we breathe in the aircraft. The investigations are part of a procedure to determine the circumstances of death under British law under the direction of a coroner (coroner) of Her Majesty the Queen. He has the competencies of an examining magistrate and is absolutely independent of political influences. In this case, on February 16, 2015, Coroner Stanhope Payne felt compelled to officially inform both the former employer of the deceased pilot ( British Airways ) and the British civil aviation authority ( CAA ) of his findings and called on them to take immediate action. The company and the authorities rejected such measures, citing the industry's own investigations from previous years.

The Brady case

Until the summer of 2015, the same team of doctors and scientists autopsied other crew members who had died unnaturally and found evidence of the same damage to the heart muscle tissue in all cases. Other possible causes for this could be ruled out. The last to die was British Airways flight attendant Warren Brady. This was reported by representatives of the science team at a recorded press conference in Berlin on July 15, 2015.

Brady Microscopy

Occurrence

The Federal Bureau of Aircraft Accident Investigation (BFU) published a paper entitled “Study” on such incidents in 2014. Its British counterpart, the Civil Aviation Authority , recorded 1,050 incidents of contaminated cabin air in 2006, 444 of which relate to Boeing 757 aircraft and another 233 to BAe 146 aircraft, which are the most frequently affected aircraft types. Except in the known and noted cases (fume event), even in the normal state, the cabin air contains some vaporized oil, as small quantities can get into the bleed air at any time.

A parliamentary request on the initiative of Bündnis 90 / Die Grünen to the federal government showed in January 2015 that the official statistics for incidents with cabin air in Germany are led by the Boeing 757 aircraft, followed at some distance by Airbus aircraft.

In April 2015 the UK Daily Mail reported that there were 167 incidents with contaminated cabin air reported by pilots from December 2014 to March 2015 alone. Of these, 12 were so serious that the pilots made an early landing. In two cases there was even an emergency report. Many former pilots and flight crew members complain that they have suffered long-term illnesses from aerotoxic syndrome.

Research program

The EASA has the MHH commissioned and a Fraunhofer Institute with an investigation into the contamination of cabin air. The cabin air is to be examined in normal conditions and at "fume events".

The European Commission and EASA have initiated a follow-up study on cabin air. The FACTS study is being carried out by a consortium of research institutions and industry.

various

Air inlets for air conditioning on a DC-8-63F
  • In 2001 the Aviation Organophosphate Information Site (AOPIS) was founded in Australia , in which pilots and crew members who believe they suffer from an aerotoxic syndrome organize themselves. Another group with similar goals is the Aerotoxic Association , which is also active in Germany.
  • The Internet service Aerotoxic Team is based in Switzerland . Information is available here in German, English, Dutch, French and Spanish
  • In Australia, a flight attendant was paid € 97,000 in compensation for pain and suffering after she was exposed to oil fumes and has since suffered from breathing difficulties. A similar lawsuit is pending in Germany.
  • In August 2010, due to growing criticism, Deutsche Lufthansa announced that it wanted to examine urine samples from its flight crew for the neurotoxin TCP .
  • The Douglas DC-8 (except for the DC-8-70s, some of which use bleed air) and the Boeing 787 are the only commercial aircraft that do not feed the breathing air through a bleed air system , so that the cabin air is contaminated in this way Gases from engine oils is impossible. Nevertheless, similar pollutant concentrations (including TCP) in the cabin as in the other aircraft types were detected during measurement flights in the Dreamliner.
  • The medical center at the University of Nebraska has developed the only method in the world to date (as of October 2012) that can be used to determine whether a person has been exposed to triorthocresyl phosphate using a blood sample. Triorthocresyl phosphate was found in the blood of the co-pilot, who suffered from severe nausea, gag reflex and a drop in blood pressure in November 2011.
  • Crews suffer more from respiratory problems due to the constant presence in dry air.
  • So far, only the new Boeing 787s have installed separate electric compressors with the aim of reducing weight and fuel consumption. Airbus opted for the classic method for the competitor model Airbus A350 : it requires less maintenance.
  • On July 15, 2015, the Berlin aviation journalist and filmmaker Tim van Beveren published a 120-minute film documentary entitled " Inhaled Unfiltered - The Truth About Aerotoxic Syndrome ".
  • In 2016, a new electrical air conditioning system from Liebherr-Aerospace Toulouse was successfully tested on an Airbus A320neo that uses outside air instead of bleed air. So far, however, this system has only been available as an "option" on customer request.

literature

  • John Hoyte: Aerotoxic Syndrome: Aviation's Darkest Secret , 272 pages, Pilot-Press, July 2014, ISBN 0-9929508-0-5
  • Schopfer LM, Furlong CE, Lockridge O: Development of diagnostics in the search for an explanation of aerotoxic syndrome . In: Anal. Biochem. . 404, No. 1, September 2010, pp. 64-74. doi : 10.1016 / year from 2010.04.032 . PMID 20447373 .
  • Hale MA, Al-Seffar JA: Preliminary report on aerotoxic syndrome (AS) and the need for diagnostic neurophysiological tests . In: Am J Electroneurodiagnostic Technol . 49, No. 3, September 2009, pp. 260-79. PMID 19891417 .
  • Abeyratne R: Forensic aspects of the aerotoxic syndrome . In: Med Law . 21, No. 1, 2002, pp. 179-99. PMID 12017442 .
  • Gross H: ["Aerotoxic syndrome:" Danger caused by hydraulic oil in aircraft?] . In: Dtsch. Med. Wochenschr. . 135, No. 19, May 2010, pp. P18. doi : 10.1055 / s-0030-1247682 . PMID 20461667 .
  • Schwarzer M, Ohlendorf D, Groneberg DA: Aerotoxic syndrome . In: Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Ergonomie . 64, No. 2, March 2014, pp. 119–121. doi : 10.1007 / s40664-014-0023-7 .
  • Abou-Donia MB: Organophosphorus Ester-Induced Chronic Neurotoxicity . In: Archives of Environmental Health . 58, No. 1, 2003, pp. 484-497.
  • Carletti et al .: Reaction of Cresyl Saligenin Phosphate, the Organophosphorus Agent Implicated in Aerotoxic Syndrome, with Human Cholinesterases: Mechanistic Studies Employing Kinetics, Mass Spectrometry, and X-ray Structure Analysis . In: Chem. Res. Toxicol. . 24, No. 1, 2011, pp. 797-808.

Web links

Individual evidence

  1. ↑ Archive link ( Memento from September 25, 2011 in the Internet Archive )
  2. ↑ Tim van Beveren: Aerotoxic Syndrome: Dangerous vapor clouds in passenger planes. In: welt.de . February 1, 2010, accessed October 7, 2018 .
  3. ↑ Archive link ( Memento from January 2, 2016 in the Internet Archive )
  4. ↑ Current status of Cabin Air Quality ( Memento from January 2, 2016 in the Internet Archive )
  5. ↑ Contaminated cabin air ( Memento from January 2, 2016 in the Internet Archive )
  6. ↑ Airlines: Poison in the plane? ( Memento from May 11, 2011 in the Internet Archive )
  7. ↑ About the aerotoxic syndrome ( Memento from August 18, 2010 in the Internet Archive )
  8. ↑ Contaminated cabin air on board commercial aircraft (PDF; 63 kB). Answer of the Federal Government to the minor question from MPs Winfried Hermann, Peter Hettlich, Cornelia Behm, other MPs and the Alliance 90 / THE GREENS parliamentary group, printed matter 16/12023, March 5, 2009.
  9. ↑ https://dibs.duke.edu/scholars/mohamed-abou-donia
  10. ↑ Mohamed B. Abou-Donia, Kenneth R. Wilmarth: Neurotoxicity resulting from coexposure to pyridostigmine bromide, deet, and permethrin: Implications of gulf war chemical exposures. In: J. Toxicol. Environ. Health. 1996; 48, pp. 35-56.
  11. ↑ a b Federal Association of the German Aviation Industry: Status Report: Quality of Cabin Air in Commercial Aircraft | March 2017 ( Memento of the original from August 5, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed on August 5, 2017 @1@ 2Template: Webachiv / IABot / www.bdl.aero
  12. ↑ http://www.aero.de/news/Forscher-weise-Nervengift-TCP-bei-FlugpassAGEN-nach.html cabin air, researchers detect neurotoxin TCP in flight passengers , in aero.de, date: September 19, 2011, Retrieved October 5, 2011
  13. ↑ https://www.researchgate.net/publication/36201353_Die_Trikresylphosphatvergiftung_experimentelle_Klarung_von_Problemen_der_Atiologie_und_Pathogenese
  14. ↑ T. Weiß, B.Schindler, A.Schütze, HC Broding, J.Bünger, C.Felten, J.Hedtmann, T.Brüning in abstract industry conference “Air Quality in Commercial Aircraft”, Hamburg June 4, 2013
  15. ↑ B. Schindler: “Development and application of an analytical method for determining the metabolites of flame retardants on the basis of phosphoric acid triesters in human body fluids”, dissertation, University of Erlangen-Nuremberg, 2009
  16. ↑ cf. P. 99, B. Schindler: “Development and application of an analytical method for determining the metabolites of flame retardants based on phosphoric acid triesters in human body fluids”, dissertation, University of Erlangen-Nürnberg, 2009
  17. ↑ http://bleedfree.eu/wp-content/uploads/2015/10/B757-air-filter-EASA-STC.pdf
  18. ↑ http://www.welt.de/bin/case-study-130712813.pdf
  19. ↑ http://www.judiciary.gov.uk/wp-content/uploads/2015/03/Westgate-2015-0050.pdf
  20. ↑ https://www.youtube.com/watch?v=moZFD65FPE4
  21. ↑ http://www.austrianwings.info/2015/07/neue-erkenntnisse-zum-aerotoxischen-syndrom/
  22. ↑ BFU study on "Fume Events" (PDF; 3 MB)
  23. ↑ http://www.wdr.de/tv/markt/sendungsbeitraege/2010/0329/download/100329-Airlines_Tabelle_plusminus.pdf ( Memento from August 21, 2010 in the Internet Archive )
  24. ↑ David Learmount: Many pilots 'medically-impaired' due to toxic cabin air , in Flightglobal.com, date: February 26, 2015
  25. ↑ Per Hinrichs, Tim van Beveren: Air in a plane can kill brain cells , in Welt.de, date: July 30, 2014, accessed: August 7, 2014
  26. ↑ Tim van Beveren, Per Hinrichs: Airlines endanger passengers with toxic fumes. In: welt.de . February 8, 2015, accessed October 7, 2018 .
  27. ↑ http://www.dailymail.co.uk/news/article-3049700/167-cases-toxic-air-planes-just-four-months-Twelve-cases-result-pilots-requesting-priority-landing.html
  28. ↑ David Learmount: EASA awards contract for cabin air contamination research , in Flightglobal.com, Date: March 18, 2015, Accessed : April 17, 2015
  29. ↑ www.aopis.org (Aviation Organophosphate Information Site) ( Memento of February 4, 2005 in the Internet Archive )
  30. ↑ Official website of the Aerotoxic Association ( Memento from August 19, 2010 in the Internet Archive ) ( archive link: German, link: English)
  31. ↑ "Flying only with an oxygen tent" . In: Süddeutsche Zeitung GmbH , August 20, 2010. Accessed October 1, 2012. 
  32. ↑ Toxic air on board: urine test for Lufthansa crews. In: focus.de. August 17, 2010, accessed October 1, 2012 .
  33. ↑ Bernd Vetter: Pioneers of the Jet Age, DC-8 , Gera Mond Verlag, Munich (2001) ISBN 3-932785-86-X pages 87-88
  34. ↑ a b c zeit.de: Aerotoxic syndrome: uncertainty about toxic air in aircraft , Rainer W. During, October 10, 2012
  35. ↑ Bundestag: German Bundestag Drucksache18 / 1168618. Election period March 24, 2017 Response of the Federal Government to the minor question from MPs Markus Tressel, Stephan Kühn (Dresden), Peter Meiwald, other MPs and the Alliance 90 / THE GREENS parliamentary group - Printed matter 18/11385 - Contaminated cabin air in aircraft , accessed on 5 August 2017