Investigations are underway to determine whether asbestos found in a park was illegally dumped or was part of the mulch as authorities rush to confirm whether other playgrounds across Melbourne's west are affected.
Jason Murphy reported the items found at Donald McLean Reserve in Spotswood, west of the CBD, with two fragments confirmed to be asbestos on Wednesday.
The Yarraville father of two was visiting the park on Monday with his children when he made the discovery.
"I was sitting under a tree near some mulch when I noticed a piece of wood still in it," he said.
"I just thought, 'well that's weird, I wonder what else is here?' And then I found crunched-up building material, insulated wire and this white composite material."
Mr Murphy doesn't believe there are effective systems to stop dangerous items being used in mulch near public spaces.
"I am just furious that people would be so careless about children's safety and someone needs to be held accountable," he said.
"There is no way that this is the only playground where this is used."
Hobsons Bay City Council will now check more playgrounds across the area for asbestos.
"We are conducting a thorough inspection of all open space and conservation areas where we have used recycled mulch from this specific supplier," it said.
The council, which covers the suburbs of Altona, Brooklyn, Laverton, Newport, Seabrook, Seaholme, South Kingsville, Spotswood, Williamstown and Williamstown North, says it's working with Victoria's Environmental Protection Authority.
"The safety of our community is our priority and council is working with the EPA and (a) hygienist to inspect other sites using this mulch," a council spokeswoman said.
"There are two types of mulch used on the reserve – a recycled product around mature tree planting and a virgin soft mulch around the playground.
"The two pieces of material were found in the recycled product."
Council was made aware of the find after Mr Murphy posted a photo of the compound material to social media Reddit.
"New Spotswood children's playground has tanbark made of old building materials, including wood with nails and a suspicious piece of compound material," he wrote.
The playground has been closed since Tuesday after a hygienist inspected the site.
All playgrounds in the area are regularly inspected by a safety auditor, the council said.
Protection agency director of regulatory services Duncan Pendrigh said there were two possibilities.
"One is someone's dumped a trailer-load of mulch against the tree and it's got mixed up into the mulch, or the mulch producer's got some contamination in a batch of mulch," Mr Pendrigh said on ABC Radio.
"We will investigate both those possibilities."
An agency spokeswoman said it was advising the council on the clean-up.
Earlier this week, Victorians were urged to avoid free garden mulch from online marketplaces after asbestos was detected in one batch.
The protection agency conducted precautionary inspections of 59 commercial mulch producers and found no traces of asbestos in their garden mulch products.
Testing was triggered after fragments of bonded asbestos were detected in Sydney's Rozelle Parklands in January.
Queensland authorities have identified at least 90 sites for investigation.
