Fumes from various non-fire related sources may sometimes be experienced within the cabins of passenger aircraft.
Sources
Most modern passenger aircraft are equipped with pressurised, climate-controlled cabins. In spite of the aircraft designers’ intentions, unwanted fumes frequently permeate the interior of the aircraft. Open doors and hatches as well as certain on-board sources can introduce fumes to the cabin environment. However the usual path of entry for fumes is via the aircraft pressurisation and air conditioning systems.