LAS VEGAS (KTNV) — Delta Air Lines is taking aggressive action to address toxic fumes in airplane cabins by replacing auxiliary power units (APUs) on more than 320 planes in its Airbus fleet, an ongoing project that is now more than 80% complete.
The initiative targets what flight attendants and pilots call the "dirty sock smell" — a health and safety hazard caused by toxic smoke, fumes and odors leaking into airplane air supplies.
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As 13 Investigates first reported in 2018, the problem stems from how some airplanes are designed. Aircraft use "bleed air" systems where fresh air enters jet engines, some bleeds off, mixes with recycled cabin air and gets pumped back inside the cabin. When gaskets leak, fumes from hydraulic fluids, oils or de-icing agents can contaminate the air system.
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"The engine oils contain neurotoxic additives," said Judith Anderson with the Association of Flight Attendants, which represents nearly 50,000 employees at 20 different airlines.
Anderson said engine oil fumes contain a complex mixture of chemicals that can include carbon monoxide.
The union is tracking thousands of cases with symptoms including hypoxia, headaches, dizziness, feeling faint, confusion and sometimes incapacitation.
One flight attendant, who asked to remain anonymous for fear of losing his job, described a severe fume event that sent him to the emergency room.
"Smell kept getting intense, intense, started to get light-headed, wanting to throw up," he said.
The flight attendant said doctors detected high levels of carbon monoxide in his blood after the incident. He now suffers from a persistent cough and requires an inhaler.
Anderson said the industry has known about the problem since the 1950s and believes the solution is straightforward.
"My 11-year-old can recognize that it doesn't make sense to compress air in an engine that can leak oil and feed that air to people in an enclosed space without putting a filter on board," Anderson said.
The issue has sparked multiple lawsuits. A group of flight attendants previously sued Boeing over a fume event on an Alaska Airlines flight, with that case settling in 2019 before trial.
A new lawsuit filed September 3 targets JetBlue, Airbus and power unit manufacturer Honeywell, accusing the companies of conspiring to keep the severity and frequency of fume events secret from the FAA, crew members and the flying public.
Boeing declined to provide an interview but sent a statement saying that while advocacy groups claim bleed air could be a health risk, "Boeing has not changed its position that cabin air is safe to breathe."
Boeing's Dreamliner 787 doesn't use bleed air, instead generating air through compressors, but it's the only aircraft using that system.
Other airlines are addressing toxic fumes through different approaches. United Airlines is conducting proactive maintenance and seal replacements, while American Airlines is upgrading APU seals.
“Delta’s safety management system and safety culture help us address root causes of potential issues to reinforce that air transportation remains the safest form of travel in the world,” said Delta Airlines.
Delta provided additional information to Channel 13:
- Smoke, fumes and odor events are exceedingly rare, though we take each seriously, as we do with all matters of safety. Delta and Delta Connection operate approximately 5,000 daily flights.
- Delta’s safety management system, approved by the FAA, is designed to uncover and resolve a host of safety issues including smoke, fumes and odors.
- Through employee reporting, data sharing among industry partners and other airlines, maintenance investments, and redundant safety mitigations, we continue to improve how we manage root causes and reduce the occurrences of these events.
- Strong employee reporting has shown that smoke, fumes and odor events originate from different sources. For example, some smells on the A320 family can come from one drop of oil leaking into the air conditioning system while other smells on the A330 indicate the need for oven cleaning. Delta is addressing both – with APU improvements on the A320 family and revamped oven cleaning on the A330 fleet – along with all other known root causes.
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