In 2014, while flying a plane full of passengers for a subsidiary of United Express, pilot Richard Papp said he became so overwhelmed with nausea and dizziness that he “couldn’t think straight” and could barely fly safely, after inhaling what he said were noxious fumes permeating the cockpit.

“At the end of the day, we couldn’t even put a sentence together,” the U.S. pilot said in an interview with POLITICO.

Papp’s case isn’t an isolated one.

On February 17, an easyJet flight to Venice had to return to Belfast after passengers detected “a strong smell” of gas, according to the Belfast Telegram. In 2015, six people complaining of fumes on board a U.S. Spirit Airlines flight had to receive medical attention upon landing. Last year, seven people on another Spirit flight had to go to a hospital after they were “overcome by fumes” smelling like oil. A third Spirit flight last year was forced to land prematurely in Los Angeles because of fumes in the cabin. At least four lawsuits have also been brought by flight attendants.

But despite cabin crews’ calls for investigations and tougher rules to ensure that engine oils don’t bleed into cabin air, so far regulators in the U.S. and the EU aren’t convinced that any danger posed to crews warrants significant action.

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The Federal Aviation Administration said there have been 204 fume events recorded in its “Service Difficulty Reports” (SDR) database since October. In a 2013 report to Congress, the FAA said it found 69 such events between 2002 and 2011. But others paint a very different picture of how often fume events happen on board — for instance, a Kansas State University study that surveyed the SDR as well as a NASA database of aviation safety reports and other sources, found that the annual number was likely much higher, estimating on average almost 2,000 fume incidents per year from 2007 to 2012.

The FAA said it “thoroughly investigates these events and makes sure the cause is addressed before the aircraft is returned to service.” A spokesperson also noted that “modern aircraft have highly effective environmental control systems that filter air as it is circulated throughout the aircraft cabin, and multiple studies over the years have consistently concluded that cabin air meets or exceeds health and safety standards.”

But pilots and at least one independent researcher say there’s just not enough consistent data to make those conclusions.

Two years ago, the FAA warned in a safety alert that airlines and pilots should ensure their procedures and check-lists address what to do about odors and fumes on board and asked operators, manufacturers and regulators to boost efforts at prevention. But the FAA hasn’t ordered manufacturers to actually change the way air on most planes gets funneled into the cabin, which pilots say can be fouled by engine oil intermixing with breathable air, due to the planes’ design, combined with poor maintenance and faulty seals.

The situation in Europe is much the same. The European Union Aviation Safety Agency (EASA) published two studies in 2017 finding that cabin air quality “is similar or better than what is observed in normal indoor environments” and that the concentration of substances that could cause health problems to be “too low to be major concern for neuronal function.” The agency will publish another study on oil contamination incidents on flights in April.

“EASA has not identified concerns that would justify to mandate general design changes or to amend products certification specifications,” said EASA spokesperson Janet Northcote, despite reports of more than 100 fume incidents in 2017 and 2018.

In January, EASA invited pilots, manufacturers and airlines to Cologne to discuss cabin fumes, where pilots were keen to emphasize the threat. The European Commission is considering launching a study on fumes’ health effects on pilots.

The battle over research

Susan Michaelis, an aviation consultant and researcher with a specialty in cabin air quality at Scotland’s University of Stirling, said in a 2011 paper that it’s impossible to know the “true extent” of instances of contaminated air because airplanes typically don’t have, and aren’t required to have, detection systems. In addition, she said the current system of self-reporting fume issues is ineffective.

Beyond that, Michaelis argued that there’s “an almost industry-wide concerted effort to marginalize and control how the contaminated air issue is addressed.” The industry has formed “a powerful coalition that ignores or manipulates external data and works towards a solution agreeable to its partners,” she wrote, comparing it to Big Tobacco and the asbestos industry.

“Effectively all data that implies there is a problem has been brushed aside in favour of commissioning yet more research that has reached the stage of going around in circles, and ignoring the fact that the toxicity of heated jet engine oil was already recognized in 1954,” Michaelis wrote.

U.S. Senator Richard Blumenthal, who has introduced a bill that would require planes to have carbon monoxide sensors and order the FAA to better record and monitor fume events, said in an interview that “the FAA has put this issue on automatic pilot and it’s going nowhere so far. It’s failed to really address the problem, and it’s putting air travelers in peril.”

“The air inside containers flying hours on end for hundreds or thousands of miles is among the most dangerous breathed by travelers or anyone else these days,” he said. “Pilots and flight attendants are rightly concerned, but so should be all of the traveling public.”

He also said he trusts independent researchers’ findings more than the FAA when it comes to incident data. “They may be defining fume events to favor the airlines. All too often on health and safety issues over the years the FAA has been partial to the industry’s interests over the public interest,” he said.

Most commercial aircraft flying today, except for Boeing’s 787 Dreamliner, produce compressed air in the engine, which is then siphoned off and used in the plane’s cabin, a feature known as a bleed system. Pilots complain that because of imperfect seals and the way the system is designed, chemicals from engine oil or hydraulic fluid sometimes seep into the air conditioning system, contaminating the air and affecting crew health. Passengers can be affected too, but because most don’t fly as frequently as pilots and flight attendants, they are usually less affected by strong fumes, pilots contend.

Pilots say they have come to know the smell, frequently described as reminiscent of dirty socks or magic markers.

“I have smelled that my whole career since I started flying for the airlines in 2002,” said one pilot for a major U.S. airline, who flies an Airbus A320 and asked for anonymity to protect his career.

When asked what Airbus is doing to mitigate the risk of cabin fumes, a spokesperson for the company said: “Airbus cabins are designed to prevent air contamination under normal operating conditions.” A Boeing spokesman said in a statement that “in the rare instances where low levels of contaminants may be present in bleed air, all reliable scientific data currently available has concluded that the cabin air in Boeing aircraft remains safe.”

Clean air calls

Brussels Airlines pilot Rudy Pont said he went to EASA’s meeting on cabin fumes with three recommendations — to build better filtration systems, to install sensors that could measure and warn of air quality problems, and to develop standardized medical protocols when cabin air is contaminated.

But Pont said it’s an uphill struggle. “Just recognition that there is a problem is something we’ve been fighting for years and years.”

Flight attendants have filed at least four lawsuits against Boeing, alleging harm caused by cabin fumes.

One of the suits was brought by former flight attendant Cynthia Milton, who is suing Boeing, alleging fume exposure on board a 767 damaged her health and made her unable to work. Milton said she blacked out while working on board an international flight; the plane had to divert to Canada to take her to a hospital. Since the incident, Milton claims she has to use oxygen daily.

“I’ve lost everything,” said Milton, who filed suit in late January for damages. “I no longer can work. I’ve lost my home. I was a perfectly healthy person but I’ve lost every bit of health I’ve had — and so my ultimate goal is that this never happen to anybody else.”

One Alaska Airlines flight attendant, Vashti Escobedo, sued Boeing in 2016 after what she said was a single bad fume event. She alleged in the lawsuit that she experienced daily migraines, blurry vision and memory and concentration problems. The suit was recently settled.

Boeing declined to comment on the lawsuits.

British union Unite filed a case last year against major U.K. airlines including easyJet and British Airways for exposing their employees to toxic air; a ruling is expected next year. British Airways says there is nothing wrong with its cabin air quality.

While far from admitting fault, some airlines are reacting.

Pilots said that some U.S. airlines, such as American Airlines, JetBlue, Spirit and Frontier, have already changed their check-lists to underline the importance of pilots putting on oxygen masks when they smell fumes.

German carrier Lufthansa said it has invested €2 million to improve cabin air quality. The airline said it is testing a filter called HEPA/CARBON, and is participating in a study on cabin air quality by the German Institute for Prevention and Occupational Medicine, the results of which are expected this year.

Britain’s easyJet has almost finished a retrofit of its fleet with “high performance carbon recirculation filters.”

“We feel we’re at the forefront of the industry in dealing with this issue,” an easyJet spokesperson said.

But some check-lists for other airlines are still too cumbersome and take too long to complete to prevent fume incidents, pilots say. Maintenance crews on the ground also have trouble replicating the issue.

While pilots haven’t gotten the traction they would like at EASA, they have had more luck at the European Committee for Standardization (CEN), a body that develops and defines voluntary standards at a European level. There, the pilots managed to get a draft set of guidelines approved by the committee, which will be up for a final vote later this year.

But EASA is reacting to the attempted end-run around its regulations. The agency sent a letter, seen by POLITICO, to CEN disagreeing with the standards. The draft agreement “contains some elements that appear controversial and that are not supported by results of research studies conducted to date,” read the letter from EASA’s Head of Strategy and Programs Massimo Mazzoletti, dated January 14.

Airline lobbies IATA and A4E also sent a joint letter, also seen by POLITICO, to CEN in November. “The highly prescriptive requirements set out in this draft are out of proportion to any demonstrated risk,” the letter read.

The ultimate solution some pilots want is to have pure, clean outside air compressed from electronic compressors instead of being shunted through hot engines that may contain chemicals.

“There is enough research” on the subject, said Pont, the Brussels Airlines pilot. “The time to act is now.”

Saim Saeed contributed to this report from Brussels. Daniel Lippman and Brianna Gurciullo contributed from Washington.

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