Airplane Cabin Fumes: Regulations, Research and Related Lawsuits

In a letter dated September 25, 2025, numerous members of Congress wrote to the Federal Aviation Administration (FAA) urging it to expedite the development of a standardized reporting system for airline employees to report fume or smoke events on board passenger-carrying aircraft.[1] The letter also called for the implementation of certain requirements outlined in the FAA Reauthorization Act of 2024, such as the issuance of recommendations for improving overall cabin air quality and rulemaking from FAA on flight and ground crew member trainings and onboard detectors. While the health effects of toxic fume events on airplanes are debated, and occurrences are exceedingly rare from the perspective of occupants, the ongoing call for further research and administrative action draws attention to the associated legal exposures and potential for future claims associated with these events.

Presently, federal aviation regulations require that the crew and passenger cabins on planes are supplied with air that is free from harmful or hazardous concentrations of smoke, vapor or toxic or noxious fumes. Specifically, regulations require that a plane’s ventilation system provides the equivalent of .55 pounds of fresh air per minute per occupant.[2] This requirement extends to normal operating conditions, as well as situations where there are ventilation system failures or malfunctions. The air on commercial passenger flights is made up of a mix of fresh engine “bleed air,” supplied via a plane’s environmental control system (ECS), and recirculated airflow. The recirculated air is filtered through High Efficiency Particulate Air (HEPA) filters to remove particle pollution. While HEPA filters remove 99.97% of particulate matter, they do not remove gases and vapors—this only occurs if an airplane has a gaseous filtration system.[3] When smoke, vapor or noxious gas contaminates a plane’s cockpit or passenger cabin it is often referred to as a “fume event.” An example of this occurring would be if there was an Auxiliary Power Unit (APU) or engine leak, and oil or hydraulic fluid seeped into the bleed air system, contaminating the air supplied to the plane’s cabins. While FAA requires airlines to file reports if such incidents occur,[4] there is no exact definition as to what constitutes a fume event. Airline crew members and passengers who have reportedly been involved in fume events have complained of both immediate symptoms, such as irritation of their eyes and nose, confusion, dizziness and/or headache, as well as long term effects (collectively referred to as “aerotoxic syndrome”).

Cabin air quality and the health-related risks associated with air contamination have been a point of discussion and research for many years. Beginning in 1984, Congress instructed the National Academy of Sciences (NAS) to conduct a study on the topic.[5] NAS published a report stating there was a lack of scientific data available for evaluation but did include a recommendation that cigarette smoking be banned on all commercial airlines.[6] In 1994, Congress mandated FAA to work with the Centers for Disease Control and Prevention (CDC) to establish an aircraft cabin air quality research program.[7] Similar initiatives were undertaken in the years that followed. In a 2015 report titled “Aircraft Cabin Bleed Air Contaminants: A Review,” FAA outlined the difficulties surrounding studying potential health-related risks associated with fume events, pointing to, among other factors, a lack of comprehensive data due to the infrequency of the fume events.[8] The report explained that the likelihood of an event occurring was 2.7 to 33 events per million aircraft departures. As part of FAA Reauthorization Act of 2018, FAA was required to commission a bleed-air quality study that included research surrounding potential health effects, technologies available to monitor and warn about bleed air contamination, and ways to avoid future fume events.[9] An interim report was submitted to Congress in 2020 in which FAA stated that early detection of system problems and preventive maintenance procedures are key to preventing bleed air contamination,[10] and subsequent studies on potential sensor technologies were conducted in 2022 and 2023. As of today, FAA is in the process of complying with the requirements of the 2024 FAA Reauthorization Act.

On April 9, 2025, a United Airlines flight attendant brought a lawsuit against Airbus SE, a European aircraft manufacturer for injuries she had allegedly suffered as a result of being exposed to contaminated cabin air. She sought $30 million in compensatory and punitive damages, arguing that Airbus was negligent in its design of its ECS, which allegedly allowed toxic chemicals to seep into the circulating air, and for its failure to warn airlines and employees about these dangers.[11] In response, Airbus filed a motion to dismiss for lack of personal jurisdiction and failure to state a claim. As part of its motion, Airbus argued that the claims lacked particularity and appeared to allege grievances against the airline industry as a whole. The lawsuit was ultimately voluntarily dismissed on July 3, 2025. The terms of the dismissal were not made public, but the lawsuit serves as an example of the nature of potential claims that may emerge should similar alleged “fume events” occur in the future.

Law Clerk Deanna Rooney contributed to this article.

[1] See Letter from Chris Pappas et al., U.S. Cong., to Bryan Bedford, FAA (Sept. 25, 2025) (on file with author).

[2] 14 C.F.R. § 25.831(a) (2025).

[3] See FAA, Cabin Air Quality, U.S. Dep’t of Transp., www.faa.gov/newsroom/cabin-air-quality-0 (Sept. 4, 2025); Gregory A. Day, Aircraft Cabin Bleed Air Contaminants: A Review 3 (2015).

[4] See Cabin Air Quality, supra note 3.

[5] Day, supra note 3, at 1.

[6] Id.

[7] Id.

[8] Day, supra note 3.

[9] Cabin Air Quality, supra note 3.

[10] See FAA, Report to Congress: Aircraft Air Quality 2 (2020).

[11] See Complaint at 17-23, Darlene Fricchione v. Airbus Americas, Inc. and Airbus S.A.S., No. 013CL2500156 (17th Jud. Cir. Va. Apr. 9, 2025). The case was removed to the Eastern District of Virginia on April 30, 2025.