The unexpected discovery of asbestos in garden mulch near a playground has sparked the closure of one of Sydney's newest parks and sparked fears of wider contamination.
The Rozelle Parklands, built over an inner-city underground interchange for a controversial motorway project, was closed on Wednesday morning after a young child found a piece of the dangerous material and their carer alerted authorities.
Testing revealed a small amount of bonded asbestos in two samples of the mulch.
While deemed to pose a low risk to human health, the contaminated mulch was available commercially and had been used elsewhere, sparking a rush to uncover whether the problem was more widespread.
"It's very concerning that a child has come into contact with any form of asbestos, whether it is bonded or not," Mark Davies, an executive at Rozelle Interchange contractor John Holland, told reporters on Wednesday.
"This is a recycled product that is widely used, is commercially available, goes through all of the appropriate certifications and processes and we've used extensively as a result."
Mr Davies said a rigorous site walk-through and other measures failed to unearth the contamination. He declined to name the supplier of the product.
Local father and Inner West Council Mayor Darcy Byrne said the find was a serious safety concern given that thousands of children, including his kids, had used the park in the month since it opened.
He called for a thorough investigation into how the contaminated material ended up there.
"If it is verified that this was carried out by the contractors constructing the park, then the government should throw the book at them," he said.
"It is beyond belief that such a long-awaited community facility has been opened with asbestos-contaminated materials contained within it."
Transport for NSW said it was working with contamination experts and authorities including the Environment Protection Authority to ensure the site was safe.
Asbestos was found in two samples of mulch tested on Tuesday but preliminary air-quality tests the same day did not find any airborne particles outside of normal expected parameters.
"We need to understand how that material has turned up despite the checks, the accreditation and the approved rules that are in place for using recycled materials and mulch in a public space," transport secretary Josh Murray said.
While the playground itself was cordoned off on Wednesday, that area was filled with a different, completely organic mulch, he said.
NSW Health says the main concern with asbestos is long-term exposure to its dust, tiny fibres of which can be breathed in and cause scarring in the lungs.
The parkland sits above the Rozelle Interchange, which links a series of tollways and Sydney's Anzac Bridge.
It has been mired in controversy since it opened in November after local streets were left log-jammed with traffic during peak hour.