Fragments of asbestos have been uncovered in recycled mulch in outer western Sydney, widening the environmental scandal beyond state government projects.

The pieces of the hazardous material were found in two landscaped areas of Regatta Park in Emu Plains after an audit of projects in the past 18 months.

The audit examined projects linked to Greenlife Resource Recovery Facility, the same supplier ordered this week to stop selling recycled mulch after bonded asbestos was found in more than a dozen landscaped sites across Sydney.

Samples of the Regatta Park mulch will be subject to formal testing and the affected areas have been fenced off, a council spokesman said.

While low risk compared to friable asbestos, bonded asbestos can weaken and have the potential to turn into powder as it ages and is exposed to the elements.

Recycled mulch, usually made of shredded fence palings and wood pallets destined for landfill, cannot contain asbestos but occasionally has small amounts of plastic.

The discovery of asbestos in mulch has forced the closure of several parts of the new Rozelle Parklands in the city’s inner west as well as other areas associated with the road interchange underneath the site.

Authorities on Wednesday announced contamination had also been found in landscaped areas of the Prospect Highway in the city’s west and three sites along the City and Southwest Metro line.

All were transport department projects led by private contractors, most of whom had engaged Greenlife to supply recycled mulch.

Greenlife however has dodged blame for the contamination, stating its processes and independent testing showed it was supplying clean mulch to clients.

“Greenlife cannot be held responsible for how its products are used once delivered, including if it is mixed with other materials or existing soil,” a statement this week reads.

It has also noted it was not a direct supplier of Fulton Hogan, the contractor behind the Prospect highway project.

The NSW Environmental Protection Authority says it has not ruled anything in or out in its wide-ranging investigation, including a theory that asbestos was already on each affected site.

Sydney Metro meanwhile has fenced off and begun testing landscaped areas along the Bankstown line including at Marrickville, Punchbowl, Hurlstone Park, Wiley Park and Belmore.

The precautionary measure follows tainted mulch being found at three publicly inaccessible substations along the line, which is undergoing a conversion to accommodate driverless metro trains.

– AAP