Beach debris ball investigation
The EPA’s investigation into the source of debris balls that washed up on Sydney beaches between October 2024 – January 2025 has determined they likely originated from Sydney Water’s land-based sewage treatment network.
This finding comes after a comprehensive scientific and technical investigation that found similarities between the make-up of the debris balls and samples taken from several of Sydney Water’s major waste-water treatment plants, including those at Malabar and Bondi in Sydney.
In April 2025, we issued a Preliminary Investigation Notice to Sydney Water, which requires them to undertake the following actions:
- complete oceanographic modelling of the dispersion of the debris balls
- complete a sampling and analysis program at their sewage treatment plants
- assess their deep ocean outfall systems and sewerage pipe network to identify where the debris balls originated.
These actions are designed to prevent a recurrence of the pollution events by pinpointing where in Sydney Water’s sewerage systems the debris balls originated. Sydney Water has agreed to undertake these actions and will provide reports on its progress to us over the coming months.
The organisation has also committed to lead clean-up efforts for potential future debris balls incidents in collaboration with NSW local councils and the EPA.
Reported locations
Debris balls were identified at the locations listed below:
- January 2025 – Northern Beaches (Manly, Dee Why, Long Reef, Queenscliff, Freshwater, North and South Curl Curl, North Steyne, North Narrabeen, Palm Beach), Eastern Suburbs (South Maroubra, South Coogee)
- December 2024 – Silver Beach in Kurnell, South Coast (Bombo Beach in Kiama, 1080 Beach and Pooles Beach at Mystery Bay)
- October 2024 – Eastern Suburbs (Bondi, Bronte, Clovelly, Congwong, Frenchmans, Little Bay, Malabar and Tamarama)
There have been no confirmed reports of debris balls on NSW beaches since January 2025.
Results
6 November 2024
The EPA released initial results in November, which found the balls contained mainly fatty acids, a small portion of petroleum hydrocarbons, and other materials, including human hair and various fibres.
2 December 2024
Petroleum hydrocarbon and biomarker analysis released on 2 December also showed some petroleum hydrocarbons in the balls.
4 April 2025
In April, we announced that our ongoing investigation – which was expanded in January after additional debris balls washed up on Sydney beaches – had identified Sydney Water’s land-based sewage treatment network as the most likely source.
We also announced the establishment of a Wastewater Expert Panel, which functions to provide independent scientific advice to the EPA and other relevant NSW Government agencies. It is chaired by Professor Stuart Khan, Head of School of Civil Engineering at the University of Sydney.
More information
Our ongoing advice not to touch debris balls – or any other suspicious debris found at a beach – remains current.
The public is advised to immediately report any potential debris ball sightings to Sydney Water on 132 090 and to the EPA’s Environment Line on 131 555.
Frequently asked questions
Our investigation has pinpointed Sydney Water’s land-based wastewater sewage treatment system as the most likely source of the debris balls.
Sydney Water is currently undertaking several actions to help provide additional information about the debris balls as part of a Preliminary Investigation Notice we issued them in April.
The EPA regulates and responds to pollution incidents where it is the responsible authority. This involves investigating pollution incidents alleged to have caused actual or potential environmental harm and taking regulatory action where necessary.
The decision to continue an investigation is based on several factors, including the nature and circumstances of the incident, any potential offences that may have been committed, available evidence, and the severity of harm to human health and the environment.
For more information about which organisations regulate specific types of pollution and the appropriate agencies to report pollution incidents to, see Report pollution.
As managers of public land, local councils in New South Wales (NSW) are responsible for the management and maintenance of beaches within their local government areas.
Part of this responsibility includes deciding whether to close or open a beach. These decisions are made based on the council’s risk management framework, which includes assessing whether a beach is safe for public use.
Councils are in charge of maintaining beach cleanliness, which includes removing litter, debris and natural waste. They also address localised pollution events, collaborating with the EPA and other relevant government agencies as required.
The debris balls found on beaches across NSW have had varying physical characteristics, however, they have mostly been reported as being round, black, white or grey in colour and range from a pea to a golf ball in size.