INTRODUCTION: Many questions are still being asked about the actual health effects of exposure to a fume event for airline crewmembers. To shed new light on this controversy about so-called aerotoxic syndrome, we undertook a large-scale epidemiological study.

METHODS: We present a retrospective cohort study involving 14,953 crewmembers, including 2577 exposed to a fume event and 12,376 matched controls to estimate the hazard ratio of a subsequent sickness.

RESULTS: Prevalence of diseases that could be related to the fume event based on “possible” or “probable” level and date of occurrence after the fume event was for exposed (controls): neurological 2.9% (2.9%), psychiatric 2.5% (2.4%), vegetative 1.8% (1.5%), irritative 5.1% (4.5%), and functional 2.8% (3.2%). Differences were not significant. Incidences of having any related disease are estimated at 1552 per 100,000 person-years for exposed and 1497 per 100,000 person-years for controls, with a nonsignificant hazard ratio of 1.04 (0.86–1.25) in the Cox model. A subset of 2577 matched pairs exposed/control allowing specific statistical tests for paired data confirmed the lack of difference between exposed and controls: matched-pair risk ratio for any fume event related disease was 1.07 (0.85–1.34).

DISCUSSION: Our results clearly show that fume events are not associated with significant clinical consequences for cabin and cockpit crew. This work does not support the proposal of an “aerotoxic syndrome” in association with exposure to fume events.

Klerlein M, Dubiez L. Medical consequences after a fume event in commercial airline crews. Aerosp Med Hum Perform. 2025; 96(1):12–17.