Sydney Olympic Park odours

The EPA investigated possible causes of odours at Lidcombe, Sydney Olympic Park, and Newington experienced by the community in late 2025 and early 2026. 

In late 2025 we received numerous community reports of unpleasant odours that were described as rotten-egg, garbage, burning, and chemical smells. 

In response to these reports, we worked with industry in the area to identify and reduce odour impacts on the community,

There was a significant reduction in community reports after February 2026 and this trend has been maintained.

The EPA response

We conducted multiple odour surveys and investigated several potential odour sources, including:

  • Cleanaway Liquid Waste Treatment Plant (Licence number 4560)
  • Cleanaway Waste Transfer Station (Licence number 4547) and
  • Haslams Creek

Cleanaway’s Licences can be downloaded from the Public Register.

Completed actions:

  • A new licence condition on Cleanaway’s Waste Transfer Station Licence. This aims to reduce garbage odours from the site by requiring Cleanaway to install a ventilation and odour treatment system, have the system assessed by an independent expert, and prepare and implement an Odour Management Plan for the site.
  • 3 new licence conditions on Cleanaway’s Liquid Waste Treatment Plant Licence. These require Cleanaway to audit its odour management system to ensure it is functioning correctly, improve its assessment and response to developing odorous conditions, enhance monitoring and reporting, and strengthen odour management across the facility.
  • Installation of hydrogen sulphide monitors around Sydney Olympic Park to track related odours and identify whether they come from natural sources around Haslams Creek or from nearby industry.

Cleanaway's response

Cleanaway committed to a number of actions at its Liquid Waste Treatment Plant and Waste Transfer Station.

Completed actions:

  • Installed a hydrogen peroxide dosing unit on one of the tanks in its biological treatment system. This helps keep the tank operating at high oxygen levels, reducing the chemical odours that can occur when the tank becomes low in oxygen.
  • Installed and upgraded hydrogen sulphide monitors at key potentially odour-generating locations across both sites to facilitate a fast response to any future odours.

What you can do

Community reports help us understand which odours occur when and where, providing key information about odours that may affect the community.

If future odours occur, please continue to provide the following details in a report to the EPA:

  • the location where you experienced the odour
  • the time you first noticed the odour
  • how long the odour lasted
  • what the odour smelled like.

If you are experiencing offensive odour, please email [email protected]. Information about persistent odour can also be recorded using the fact sheet and odour log sheet, which can then be emailed to us. 

If you believe the odour originates from Cleanaway's facilities, we also encourage you to report it directly through Cleanaway’s complaints and enquiries process by calling 1800 213 753 or emailing [email protected]. This helps Cleanaway investigate potential odour sources in real time. 

Hydrogen sulphide monitors in the community

Between November / December 2025 through June 2026, the EPA operated five electronic monitors in the local area to detect hydrogen sulphide, a colourless gas that smells like rotten eggs, and can be a component in other odours. Hydrogen sulphide odours can come from natural sources, including creeks and estuaries, as well as from industrial activities.

These monitors took an air sample every 10 minutes and analysed it for hydrogen sulphide, detecting levels as low as 3 parts per billion (ppb).

Hydrogen sulphide detections over the monitoring period were very low and unlikely to affect human health.

Data averaged well below the 8 ppb odour detection threshold at 4 of the 5 sites.  The exception was the Haslam’s Marker monitor which recorded higher levels.  Sources in this area are likely associated with natural sources as it is adjacent to river bank. Tidal mudflats in the area naturally produce hydrogen sulfide as bacteria in the mud break down biological material.

Following a review of the collated results and the low levels recorded the monitoring program was discontinued from June 2026. The charts of the collected data remain below.

The EPA continues to work with industries in the area to minimise odour sources.

Odours and health

NSW Health advises people can smell hydrogen sulphide at very low levels. Most people notice it at around 8 ppb, but some people can smell it at levels as low as 0.5 ppb. 

Exposure to hydrogen sulphide concentrations of 5,000–30,000 ppb may cause irritation of the eyes, nose, or throat, and difficulty breathing in people with asthma. Repeated exposures at these levels can cause anxiety and distress and result in indirect symptoms such as headaches and nausea. 

These effects are usually mild and temporary. Hydrogen sulphide does not accumulate in the body, and symptoms generally resolve once the air clears. If residents are concerned about their symptoms or if symptoms persist once the odours have ceased, they should seek advice from their doctor.

Hydrogen sulphide levels

The interactive charts show levels of hydrogen sulphide detected at 5 monitors deployed in the local area. To explore the data obtained since their installation date, use the slider at the bottom of each chart.

Note: There was a gap in the collection of data from the Hill Rd Bridge monitor from 20 March to 16 April 2026. No odours were reported to the EPA in this period.