Asbestos has been confirmed at more sites across Sydney as the recycling industry asks suppliers to do more to manage contamination risks.
Canberra was also drawn into the scandal on Monday after records showed the mulch product behind each positive result was sold for nine months in the capital.
Five schools in Sydney have been found with asbestos-tainted mulch, the latest being Domremy College at Five Dock in Sydney's inner west.
The college remained open on Monday with the contaminated site isolated and cordoned off.
In western Sydney, St Luke's Catholic College at Marsden Park will be closed this week, while Penrith Christian School at Orchard Hills remains open with the contaminated site fenced off after asbestos discoveries at the two schools were confirmed on Sunday.
Seven hundred students of Liverpool West Public School are being offered in-person learning at nearby Gulyangarri Public School while tonnes of mulch are removed from their primary school.
Positive results were also reported on Monday for an Aldi supermarket at Cobbitty, Riverstone Sports Centre, and an area of a shared path along the Parramatta Light Rail project at Telopea.
Three other sites were not publicly revealed because the EPA said they were not publicly accessible.
In Canberra, it emerged Stonehenge Beltana Garden Centre imported the product linked to all positive tests.
The ACT EPA said it had been advised the mulch, marketed locally as "cottage mulch" was sold on to 24 businesses and 27 addressed in the capital area between March and November 2023.
"Records are held for many of the purchases, so most customers have already been contacted and informed by the retailer," the authority said.
"Others will be contacted in the coming days as they are identified."
The ACT EPA thanked Stonehenge Beltana Garden Centre for their proactive approach in contacting customers.
No positive results have been reported in the ACT.
Waste Management and Resource Recovery Association of Australia chief executive Gayle Sloan said the industry worked hard to manage, mitigate and address the risks of asbestos, which need to be addressed by the whole supply chain.
"Ideally material destined for recycling should be classified at the source to ensure anything not capable of being recycled - like asbestos - is not taken to a recycling facility in the first place," Ms Sloan said on Monday.
More than 40 sites including schools, hospitals and parks have been contaminated, with more than 600 areas tested.
More than 90 per cent of the mulch identified as potentially containing asbestos had been tested, Premier Chris Minns told ABC radio on Monday.
"We're getting towards the end so I don't want people to think this is never-ending," he said.
The government is considering increases to fines.
The EPA said most homes before the early 1980s in NSW were built with asbestos.
Sydney Olympic Park has been cleared before a big weekend of concerts in the entertainment precinct, including Taylor Swift's shows.
The EPA is investigating a complicated supply chain as it probes how the mulch became contaminated, but the agency chief Tony Chappel has cautioned against prematurely attributing blame.
Greenlife Resource Recovery is challenging a prevention order in court and said its mulch is independently tested by approved laboratories and the company was confident it left its facility free of contamination.
The EPA has previously issued notices at the Bringelly site in Sydney's southwest occupied by Greenlife since 2022 after asbestos fragments were discovered in 2016.
A company spokesperson said the site was subject to comprehensive clean-up and remediation works, undertaken by the previous occupants and accepted by the EPA before Greenlife started operations there.
