SYDNEY AIRPORT: Air Traffic Control stinks! Sewage smell overwhelms control tower

Air traffic controllers at Sydney Airport were forced to work through overpowering sewage odours during the peak 2024–25 holiday travel period. Some staff were reportedly dry heaving at their desks while managing aircraft movements according to a story in the Sydney Morning Herald. Incident logs from Airservices Australia show the first complaint was recorded on December 17, 2024, describing a “foul smell entering the tower cabin environment”.

The smell overlapped with the busiest travel period Sydney Airport has ever recorded.

Unpleasant conditions

Controllers reported nausea and discomfort while on duty, with employees stating they felt sick during their shifts. One staff member commented that the control tower was “heavily affected by sewer odour”. It’s not a good idea to have the top safety staff responsible for aircraft movements at an airport feeling sick due to a bad smell.

Sydney Airport handled just under six million passengers between Christmas and New Year’s.

The source was beneath the airport

The odour was traced to Sydney’s sewer system, which runs directly beneath Sydney Airport. Waste from around 1.8 million Sydney residents is carried through those pipelines to the Malabar Sewage Treatment works.

The odour control systems failed, allowing sewer gases to escape into the control tower rather than being filtered as designed.

The smell was hydrogen sulphide (H₂S), a toxic gas produced by decomposing sewage. Gas levels were measured at more than 5 parts per million (PPM). Safe exposure levels are around 1 PPM.

Concentrations around 5 PPM can irritate the eyes, nose and throat and cause headaches, dizziness and nausea. Not what you want your Air Traffic Controllers to be exposed to. Certainly not for a whole shift, which may have been the case in December 2024.

What went wrong underground

At Sydney Airport, the odour control unit’s activated carbon filter was clogged and needed replacement. The extra load caused the filter to not do its job properly.

Problem solved

Sydney Water replaced the carbon filter on January 10, 2025. That solved the problem, with no further odours being reported.

2PAXfly Takeout

This goes into the ‘weird things that happen in airports’ basket. Airports and airport staff are subject to the same infrastructure that we all rely on, and consequently suffer as we do when things go wrong. It’s just that here the affected staff were responsible for getting things up into the sky, and down to earth safely, with hundreds and thousands of lives in their hands. Not the people you want to subject to offensive smells!