Until now, the assumption was that mulch sold by the Stonehenge Beltana garden centre in Pialligo was largely to domestic customers for their gardens, but it has now emerged that much of it was sold to landscaping companies doing work around new apartment blocks.

It is believed that three big construction companies have been contacted by WorkSafe ACT.

On Thursday morning, one residential complex tested positive to asbestos in mulch, according to WorkSafe ACT.

The time period when potentially dangerous material was sold has also been increased.

Initially, the warning was for mulch bought between March and November last year but WorkSafe ACT has now extended the period to the beginning of this week.

"Members of the community who purchased cottage mulch from the suppliers listed below between 1 March 2023 and 19 February 2024 should contact WorkSafe ACT," the watchdog stated.

It named those suppliers as (in addition to Stonehenge):

On Thursday, WorkSafe ACT said it had issued 20 prohibition notices keeping people away from mulch on their premises.

Another nine sites were being contacted and 14 sites were booked for testing.

"We are endeavouring to contact all identified businesses and households as soon as we can," Work Health and Safety Commissioner Jacqueline Agius said.

"We understand that people are concerned, but the important thing to remember is that the safest place for the mulch right now is for it to remain undisturbed on the ground."

The WorkSafe information came as the man in charge of the garden centre which originally sold the potentially-contaminated Cottage Mulch product told people who bought the product should use the utmost care.

"It should be assumed that all sales of Cottage Mulch during the notifiable period may be contaminated with asbestos," Jack Amey, General Manager, of Stonehenge Beltana in Pialligo said.

Mr Amey said that up to 60 customers could have bought the material. His garden centre was "working around the clock to assure the health and safety of all customers in light of the possible asbestos contamination in cottage mulch".

"We are confident this is affecting less than 60 customers across trade and retail over the period, and we have today notified all our customers who did purchase the product that we had details for," he said.

"It's also important to remember that contamination is a possibility at this stage, and we do urge any of our customers who have purchased Cottage Mulch, to follow the instructions from WorkSafe ACT which is to not disturb or try and remove it, and to isolate it so far as is possible, then contact WorkSafe ACT for assistance with identifying and remediating."

The garden mulch potentially contaminated with asbestos has been linked to more than 40 affected sites in New South Wales. It was then confirmed that it had been available in the ACT.

Stonehenge Beltana, in Pialligo, sold the product that was supplied from Greenlife Resource Recovery Facility, a south-west Sydney business. The facility had been linked to multiple contamination sites across Sydney.