The contaminated aggregate is behind about 60 retaining walls built for much of stage 2A and some of stage 2B at the Lendlease Calderwood development.

The Environment Protection Agency has ordered Kembla Grange-based Wollongong Recycling, which supplied the contaminated aggregate, to have it all removed by March 2.

The EPA would not give an estimate of how much contaminated material there may be, but said Wollongong Recycling supplied more than 3,300 tonnes of waste aggregate to primary contractor J.K. Williams as “free draining backfill”.

The amount to be removed will be different, as the EPA’s orders cover any soil that has come into contact with the contaminated material. Some stockpiles have already been removed.

The EPA said it suspected friable asbestos to be within all the crushed material used as fill.

For the people who have bought properties in Calderwood, it means months more waiting before their land can be registered – and this could affect 500 properties.

Lendlease could not give an estimate for when the properties could be registered, and has previously dismissed talk of compensation, saying there are risks in buying off the plan.

“Wollongong Recycling is responsible for the schedule of work. Once some of the work is carried out, we will have a clearer understanding of likely registration timeframes,” a Lendlease spokeswoman said.

“Lendlease has notified residents and customers about the final phase of the clean-up, and will provide updates as the work progresses.”

Wollongong Recycling is owned by Sydney waste empire Bingo, which bought it from Helensburgh’s Blackwell family in June, about two months before this trouble started.

Bingo was contacted for comment.