Workers dressed in anti-asbestos gear have spent the afternoon digging the ground in Ropes Crossing.
Asbestos Diseases Foundation of Australia president and Blackett resident Barry Robson contacted the Star after driving past the workers near the Forrester Road entrance on Thursday afternoon.
He believes the land was being prepared to be built on.
''I know anti-asbestos gear when I see it,'' Mr Robson said.
''I've never seen them there before. It vindicates what people have been saying for years. Potential buyers should be made aware and not consider moving there until they can be given a 100 per cent guarantee that there's no more asbestos there.''
Now an estate managed by Lend Lease, it was revealed the site was contaminated with toxic waste and asbestos in 2003.
In recent years, local environmentalists have renewed calls to be shown records showing the former ADI site had toxic waste and asbestos cleared before it was developed.
"The public has a right to know,'' Shalvey resident Brent Robertson said in 2012.
''My hopes are there's nothing there but why aren't they (Lend Lease) returning my phone calls? All we want is transparency. There are people buying property and living with their grandchildren."
Lend Lease has previously said the development area underwent a thorough and transparent remediation process spanning almost 20 years and that the public aren't at risk.
The Star has contacted Lend Lease for a comment.
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