In an extensive review across multiple airlines in the LA Times, design and mechanical flaws present in common aircraft of major airlines has been filling cabins with toxic fumes from the plane's exhaust.

The air breathed in by passengers in the cabin is known as "bleed air." The air is protected until there's a technical problem—for example a broken seal. Heated jet motor oil could spill into the air stream, potentially discharging poisonous gas to the aircraft.

Vapors from oil and other fluids are penetrating aircraft at disturbing frequencies across all carriers, a recent report says. NASA's safety studies analyzed from January 2018 to December 2019 and recorded 362 fume cases reported by members of the airline crew. About 400 pilots, flight attendants and passengers reported seeking medical attention.

The airline industry and its regulatory bodies have been aware of these "fume events" for decades, and maintained that their quantities of hazardous substances are too limited to pose significant health risks.

Airlines are advertising their use of HEPA filters, cleaning practices and other precautions to convince passengers that their planes are safe. However, no government agency tracks fume events or how often people become sick or impaired. Fume events can be odorless, and some of the most common symptoms of exposure are indistinguishable from jet lag. Pilots and flight attendants have reported an array of health problems, including eye irritation, coughing, as well as more serious long-term conditions.

In a 2015 memo provided to Boeing during litigation, “Flight attendant, pilot unions, and congressional supporters could use this effort as evidence that sensors are needed and ... to drive their agenda forward to have bleed air sensors required on all aircraft,”

The LA Times report describes David Gelber, a Hawaiian Airlines passenger from Oakland in August 2019. Gelber was a passenger when smoke engulfed his cabin; he believed the aircraft was going down and children were shouting and weeping as the pilots landed in an emergency landing in Honolulu and deployed the escape slides.

A infant and a 9-year-old boy were transported to the hospital with seven passengers. Paramedics have treated one pregnant woman and first aid results indicate that hot fuel oil had penetrated the air through a defective seal.

That evening Gelber started to feel dizzy and he came down within a couple of days with a high fever and a wet cough lasting a week. "For about a half-hour passengers breathed in smoke," Gelber said who still had a cough month later. As a frequent flier, Gelber was concerned about the potential long-term health consequences of the "fume event."

One such pollutant, Tricresyl phosphate or organophosphate TCP, is a nerve agent first identified in the 1930's. Experts agree the TCP may have acute symptoms such as headaches and dizziness. Long-term effects, such as tremors and memory problems.

Cheryl Bick is a Boeing chemist known for her extraordinarily fine sense of smell. Bick said she was not permitted to wear an oxygen mask because the spectators were nervous. Bick stated, “I always did it because I wanted to help....I wanted to fix planes. I wanted to find out what was making people sick.”

About a decade ago, the FAA sponsored a study that calculated the toxicity of fumes using air samples which cost approximately $250 each. The report was commissioned by Congress. However, according to the 2014 FAA-funded study, airlines declined to allow flight attendants to carry air purification devices onboard.

Quoted in the article is Christiaan van Netten, a toxicologist and a professor emeritus at the University of British Columbia who states, “If you want to find out what the exposure is and you don’t allow them to make the measurements, then what is the point?”

The main cabin crew union, Assn. of Flight Attendants, has been calling on the FAA to intervene for more than 25 years. No major studies have ever analyzed chemicals in fumes. Fume incidents are a fraction of the thousands of flights crossing the U.S. every day. Many are unreporting or cause no obvious health effects, often synonymous with a "dirty sock" smell.

“Studies have shown cabin air is as good as or better than the air found in offices and homes,” the FAA said.