Fears of high-altitude health risks are growing. Although the evidence is still inconclusive, airlines could face mounting litigation

Airlines are used to the intense media glare following an air crash. But safety is no longer the only consumer concern to hit the headlines. Health issues were brought dramatically into the public eye by the death of 28-year old Emma Christofersen from deep vein thrombosis (DVT) after a 20-hour Qantas Sydney-London flight last October.

Relatives and campaigners blamed the Australian carrier. Within two months, a string of passengers who had contracted blood clots after long-haul flights had stepped forward. Now it looks like the issue will go before the courts. But Qantas will not be alone in the dock.

In December, Australian law firm Slater & Gordon announced it would launch a class action suit against several international airlines - including Qantas, Air France and British Airways - over failure to warn passengers about the risks of developing the condition. The accused may face the claims of between 10 and 25 litigants.

Airlines play down the risk of DVT, which has been dubbed "economy-class syndrome", as some associate it with cramped seating arrangements. "We have problems with passengers of an older age and those who already have a history of extreme widening of veins," says Lufthansa chief medical officer Dr Lutz Bergau. "But we don't see any special risk for the normal passenger, even sitting in economy class," he adds. "DVT is more of a travelling syndrome and is not specific to air travel." IATA backs this up, saying that the woman who flew with Qantas "may have died in bed the same day without flying".

While a recent report examining a wide range of health issues, including air quality and ventilation, called on airlines to provide more information to passengers about the risks of DVT, it found no evidence of a direct link with air travel. Published in November by a UK parliamentary committee, the report concluded that "for the very great majority, any risks to health from the aircraft cabin environment seem very small - and certainly less than individuals accept with little or no apparent thought in other aspects of their daily lives. For a small minority there are significant issues, although a number of these may not be unique to air travel."

These conclusions follow a similarly reassuring probe published in September 1999 by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) which examined other health-related airline issues. The study used eight medium-to long-haul flights to gather its findings. Researchers used on-board sensors to measure cabin air pressure, temperature and humidity, as well as levels of carbon dioxide, carbon monoxide and oxygen. The amounts of respirable particulates, biological organisms and volatile organic compounds were also measured. Samples were taken during the flight and as passengers boarded and left planes.

It concluded that the levels of bacteria and fungi were "relatively low", and contaminants were "particularly low" during the flight when environmental control systems on board planes were working. In addition, "there do not seem to be any significant levels of air-quality contaminants in the environmental parameters measured that would correlate with the health problems that flight attendants are reporting".

While it found carbon dioxide (CO2) levels were higher than in buildings, it concluded that "environmental CO2 on planes is comfortable for passengers".

Legal actions

Yet despite the apparent benign nature of the aircraft cabin environment, the impending case over DVT is not the first health-related legal action the industry has faced. Alaska Airlines, which in January finalised an out-of-court settlement with 26 flight attendants and their spouses, is just one of the most recent examples.

Since 1989, flight attendants from the carrier have filed more than 900 workers compensation claims for fatigue, head-aches, dizziness, disorientation, memory loss and other problems they believe stem from exposure to tainted cabin air in its McDonnell Douglas MD-80s.

Crew have claimed that maintenance records revealed a pattern of periodic leaks of hydraulic fluid and jet-engine lubrication oil into the air supply system of the jets. They argued they were victim of the toxic organophosphate compounds in these liquids, which, when mixed with cabin air can seriously impair passengers' health.

The cabin crew also alleged that the airline knew all this - indeed it was in talks with the aircraft manufacturer and the maker of the air conditioning system, AlliedSignal, to try to resolve the problem - but failed to warn employees. The plaintiffs' attorney says there are 20,000 US flight attendants claiming symptoms similar to those at Alaska.

Claims relating to contamination of engine bleed air are not confined to North America. In April 1999, flight attendant Alyssia Chew successfully sued Ansett Australia under Australia's Workers Compensation Act for damages of A$65,000 ($38,5000) because fumes from a BAe146 cockpit were found to have aggravated a medical condition. She suffered extreme fatigue and nausea, and was forced to take substantial sick leave.

Ansett maintains this was an exceptional case, attributable to Chew's rare pre-existing condition. Yet last August, another flight attendant won the right to take action against the carrier over health problems associated with fumes ingested while on board a BAe146.

In a move that signals just how seriously some airlines consider the matter, Qantas and manufacturer BAE Systems have introduced design modifications to the offending auxiliary power units and the air conditioning system on the BAe 146 to reduce the incidence of escaping fumes of this type.

BAE Systems

While the older BAe regional jet and the MD-80 have been associated with most of the claims, more modern aircraft, such as the Boeing 777, have been linked with what some scientists have dubbed "aerotoxic syndrome". According to a recent report by the American Society for Testing and Materials, this "chronic" condition is linked to "crew exposure at altitude to contaminants from engine oil or other aircraft fluids".

But for Shane Enright, who has followed the issue for years at the London-based International Transport Workers Union (ITF), this is not just an occupational health issue. He says: "Flight attendants are like canaries down a mineshaft - an early warning indicator of potential hazards to passengers."

Washington-based Aviation Consumer Action Project agrees. Like the ITF, it sees the aerotoxic syndrome as part of a wider problem of poor cabin air quality, which, among other negatives, can lead to the spread of airborne diseases such as tuberculosis. ACAP argues that the problem started in the 1970s when airlines sought to cut fuel consumption by moving away from 100% outside air to around 50%.

ACAP charges that airlines have reduced the air flow rate and is pushing for new standards. The group charges that "airlines are resisting government standards for financial reasons", estimating that it would cost a mere $1-2 per passenger per flight to "fix the problem". These accusations are roundly rejected by the industry, and even some consumer groups. "It is nonsense to say that airlines are doing these things to save money," states Dr Hans Krakauer, vice president of the International Airline Passenger Association, a group of 100,000 frequent flyers. IATA agrees, stating that the evidence suggesting health risks from poor air cabin air quality "is very inconclusive".

Russel Raymond, executive director of the Aerospace Medical Association in Virginia concurs: "If you look at studies over the past 15 years there is no compelling evidence that cabin air quality is sub-standard. If flight attendants are complaining, it is due to other factors."He cites barometric pressure, vibration, turbulence, jet lag, a dry environment and inadequate temperature control as possibilities.

Manufacturers are adamant they are victims of bad press. "It is nonsense to say the air is stale or stagnant," says Airbus spokesman David Foscou. "The air cabin environment is a lot better than the newspapers lead you to believe." Foscou touts the fact that the cabin air is changed every three minutes and says that Airbus aircraft supply "eighty times as much oxygen as passengers need to breathe".

Boeing, which has a section of its website dedicated to dispelling the "myths" about cabin air quality, accepts "some early 747s do have an economy setting that can be used to save fuel through reduced air flow," but the feature is no longer offered.

Yet one of Europe's largest airlines is convinced improvements to the cabin air environment are long overdue. "In the old days, the 747 typically carried some 370 passengers. Now it's more like 430, but today's standards still stipulate the same amount of fresh air [as before]," says Lufthansa's Bergau. "There are more and more passengers in the same space. Is this still acceptable?"

New standards

New standards are what now appear to be desired by all stakeholders, from unions to consumer groups and airlines. "We need regulations because airlines will do what they have to do [to compete on cost]," says Chris Witkowski of the AFA, which wants to see an air flow standard of 20ft3/min/person.

Lufthansa's medical chief agrees that the aircraft cabin environment could be compromised by intensifying competition among airlines, and adds his own specific demands. "The existing standard on the ratio of fresh air per occupant will have to be renewed," says Bergau. "The carbon dioxide levels, in the ASHRAE study were found to be higher than in buildings, and should be reduced," he says, adding that the FAA, for example, still allows 5,000 partsw per million (ppm) CO2. "This is far too high. It should be reduced to 1,500."

The most recent moves towards new standards in the USA were in 1997 when the FAA ruled that any aircraft up to two years old would have to conform to ventilation standards of 10ft3/ min/person. Atlanta-based ASHRAE, which sets ventilation standards for buildings, has been given the task of coming up with standards for all aircraft. With international representation from airlines, manufacturers, employee and consumer groups, it is understood that the standards it sets will be adopted globally by regional aviation authorities such as the FAA and JAA in Europe. "We are waiting for ASHRAE to set standards," says Lufthansa's Bergau.

Further research

Most agree that more research is needed to enable informed decisions on aircraft cabin quality and other health issues. IATA says the issue of DVT "warrants additional research". Raymond at the AMA admits that "the studies on air cabin quality that have been carried out [were] on a limited number of flights. Perhaps they should be done on more."

Among a number of research projects understood to be under way is a major study on DVT by Cranfield University in the UK. The country's civil aviation authority has also been tasked with investigating what, if any, health consequences arise from tight seat pitch, and to look into allegations that airlines compromise air quality to reduce fuel costs. Several airlines, including BA, are sponsoring their own studies.

More education and information to passengers on possible health risks are also needed, according to the UK parliamentary committee report last November. It wanted to see airlines forced to provide much more information to passengers at the time of booking on such aspects as the size of seat that is on offer, using unambiguous standardised options for pre-booking, particularly with those regarding extra leg-room.

But for some, health is often directly linked with comfort. "The comfort issue can be a health issue," says Krakauer at IAPA. "To say it has nothing to do with physiological effects is nonsense." AMA's Raymond agrees. "We need to look at passenger comfort. If airlines improve passenger comfort in the long run they will reduce passenger complaints and possible health problems." Airborne diseases

Airborne illnesses and diseases are said to range from common colds to influenza through to tuberculosis. But what is the chance of contracting them and what can be done about it?

Andrew Hayward from the Department of Public Health and Epidemiology at the University of Nottingham, UK, stated categorically that "no case of active TB has ever been identified that can be attributed to exposure on board an aircraft," when he addressed the Royal Aeronautical Society in April 1999.

Yet the picture is not so clear cut. Hayward also says the Heathrow airport medical authorities had approximately 140 suspected cases of TB annually, and that the risk of being infected following prolonged exposure on a long-haul flight may be as high as 31% for a passenger seated within two rows of a TB sufferer.

The danger diminishes, however, with distance: the risk of infection fell to 9% if the passenger was merely sitting within the same section of the aircraft as an infectious person. Still, effective filtration is critical.

"Recirculation of the air may increase the risk of transmission, but if air is filtered through properly functioning High Efficiency Particulate Air (HEPA) filters then mycobacterium tuberculosis should be filtered out," stated Hayward at the time.

So are the manufacturers and airlines ensuring they are properly equipped? Airbus, for one, says its new generation aircraft are fitted with HEPA filters. However, this may not be true for its older aircraft.

In the end, short of draconian measures tp separate infectious passengers, airline customers may just have to lump it. If you sit next to somebody with a cold, maybe you will catch it.


Air cabin quality is only one of a number of airline health issues. In November the Washington-based Aviation Consumer Action Project (ACAP) joined forces with Unite, a union representing airline laundry workers, to demand improvements in onboard hygiene and cleanliness. This followed a survey of union members at Royal Laundries, which services 150 airlines in the USA, who claimed they were instructed to repackage used airline blankets and headphones without cleaning them. At the same time, laboratory tests at Superior Laboratories in Columbus, Ohio, on blankets "obtained from several of the largest airlines in the world" revealed the presence of pathogens including Pseudomonas paucimobilis. This has been known to cause infections in the lungs and eyes as well as cause contamination of the blood system, says Unite.

These findings, the two organisations say, back earlier research by a number of US television stations. In 1997, WBNS-TV of Columbus, Ohio, revealed that 78% of surfaces, including blankets, pillow cases, tray tables and head rests, were contaminated with disease-causing microbes.

The study, conducted with the help of Superior Laboratories, covered all 10 major carriers serving Port Columbus International Airport and dozens of flights within the USA and to Canada. Regardless of the airline, or the cabin class, all items were "just as unclean" and had been "rarely, if ever cleaned or disinfected". Among the pathogens WBNS detected was Escherichia coli, which is potentially lethal.

Labelling the airlines "germlines", the ACAP and Unite have called on the US DoT inspector general to investigate "charges of grossly unsanitary conditions on airliners" and an end to airline exemption from "enforceable sanitary codes".

Having failed to obtain any action from the DoT, which argues that this matter is out of its remit, Unite is now issuing passengers with their own test tubes, swabs and an address of a testing laboratory. "Passengers can now see how dirty aircraft are for themselves," says a spokesman.

Source: Airline Business