NSW regulator chose to reveal content of Sydney’s mystery beach balls on day of US election

<span>Black, ball-shaped debris washed onto Sydney beaches, including Coogee, in mid-October.</span><span>Photograph: Randwick City Council/Facebook</span>
Black, ball-shaped debris washed onto Sydney beaches, including Coogee, in mid-October.Photograph: Randwick City Council/Facebook

The NSW environment watchdog allegedly knew for more than a week that thousands of mystery balls that washed up on Sydney beaches last month were probably consistent with human-generated waste before it made the news public as US election results dominated headlines.

A statement from the Environment Protection Authority (EPA) on Wednesday revealed the balls comprised fatty acids, petroleum hydrocarbons and other organic and inorganic materials – including traces of drugs, hair, motor oil, food waste, animal matter and human faeces.

Jon Beves, an associate professor at the University of NSW, said on Thursday the balls’ makeup was “consistent with human-generated waste, like the types of things you would find from domestic waste in a regular sewer”. Beves coordinated testing of the balls with the EPA. He and his fellow UNSW professor William Donald wrote in the Conversation on Wednesday that the balls “were likely lumps of ‘fatberg’”.

On 16 October, Randwick council said preliminary testing found the debris was “consistent with the makeup of tar balls”, which form from oil spills or seepage at sea. The EPA said the next day its test results matched the council’s.

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On Friday, an EPA spokesperson said: “The NSW EPA never stated the balls were ‘tar’ balls.

“Initial testing done by UNSW for [Randwick] council did find hydrocarbons were present in samples but the EPA consistently stated that more extensive analysis was needed to confirm the makeup of the balls.”

In mid-October, Guardian Australia reported the team of scientists analysing the debris was investigating whether the balls could be linked to sewage and whether they could have come from a nearby water treatment plant.

But it continued to be widely reported and understood that they were tar balls.

Guardian Australia understands the regulator knew the pollutant material was consistent with human-generated waste as early as 25 October.

The NSW Greens MP Sue Higginson said that should have been communicated immediately.

“The EPA knew what was in the public’s mind, and it was their duty to correct it as soon as they knew,” Higginson said.

“It is concerning that the EPA would choose to correct the public record about such a significant error of fact through a media release on one of the busiest media days of the last decade.”

Higginson said it was concerning that the authority had released “a much more detailed analysis, which really pivots to a completely different scenario than tar balls” on Wednesday.

Higginson said the regulator should apologise and “give the public some form of guarantee the systems that have led to these failures will be addressed and rectified”.

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She said concern for public health should be paramount considering the balls were “possibly highly toxic sewage products”.

“You’ve got human faeces, you’ve got methamphetamines, THC. All of these substances are harmful. They are pollutants. They are toxins.

“We don’t know that the point source isn’t continuing to pollute in other areas.”

The EPA spokesperson said “due to the complex makeup of both organic and inorganic materials, we are unable to definitively pinpoint a source”.

“All beaches that were impacted have been cleaned up and reopened by Randwick City council and there have been no further reports of debris.”

A Sydney Water spokesperson said “there have been no issues with the normal operations of the Bondi or Malabar wastewater treatment plants”.

“Sydney Water acknowledges the tar balls may have absorbed wastewater discharge, which was already present in the water while forming, however, they did not form as a result of our wastewater discharges.”

Higginson said: “I know Sydney Water has come out and said there is nothing wrong with our sewage systems. We need a further view on that.”

Randwick council was contacted for comment.