Source of NSW mystery beach balls finally revealed to have come from a waste treatment facility

The source of the mysterious black balls that sparked beach closures across NSW has finally been uncovered — and it’s closer to home than many expected.

Sydney Water’s Malabar Wastewater Treatment System has been identified as the likely origin of the dark, rubbery debris that washed up on 17 beaches between October 2024 and February 2025, including Bondi, Coogee, Bronte and Maroubra.

The revelation comes after months of public confusion and concern.

The EPA’s Independent Wastewater Expert Panel reviewed evidence gathered under a Preliminary Investigation Notice and confirmed the Malabar system as the likely source.

EPA issued its final media release in December outlining the test findings and did not disclose the presence of Enterococci, e.Coli and thermotolerant e.Coli.

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