The discovery of asbestos in crushed concrete stockpiles at the Broadlands Road Landfill in Taupō has raised important questions about the safety of recycled concrete as a construction material. The Taupō District Council, which operates the landfill and sells recycled crushed concrete to contractors, found asbestos in two of the samples taken from its stockpiles after a council project contractor raised concerns about the material they were using.
How Asbestos Gets into Recycled Concrete
Asbestos was widely used in New Zealand’s built environment until it was banned from new building products in the late 1980s. Buildings constructed before this period — which make up a significant proportion of New Zealand’s existing building stock — may contain asbestos in floor tiles, wall linings, ceiling tiles, pipe lagging, roofing materials, and importantly, in some concrete products.
When these buildings are demolished and the material is crushed for recycling, asbestos-containing material can be incorporated into the concrete aggregate if demolition has not been properly managed. Asbestos surveys and management plans for pre-1990 buildings are legally required before demolition, but compliance is not universal — and even compliant processes can leave trace contamination in demolition waste.
The Risk
Asbestos in solid concrete is generally considered low risk as long as the material is not friable — that is, not in a form where fibres can become airborne. However, the crushing process that creates recycled concrete aggregate can disturb bound asbestos, potentially releasing fibres. Workers handling crushed concrete without understanding this risk could be exposed without knowing it.
The Taupō case involved material that had been sold and used on active projects before the contamination was identified — which means workers and potentially members of the public may have been exposed.
What It Means for Contractors Using Recycled Material
Contractors who source recycled crushed concrete should be asking their suppliers about the provenance of the material and what testing has been done. The use of recycled aggregate from facilities with rigorous incoming waste screening and regular testing for asbestos is meaningfully lower risk than sourcing from less well-managed operations.
WorkSafe’s guidance on asbestos in construction is clear: if you have reason to believe a material may contain asbestos, treat it as though it does until testing proves otherwise. The cost of testing is small compared to the cost of an asbestos exposure incident and the regulatory consequences that follow.