Asbestos Found in Concrete Stockpiles

Stockpiled waste concrete is to be tested after asbestos was discovered in dumped concrete at Broadlands Road Landfill, the Taupō District Council reported in August.

The Council, as part of its solid waste operations, provides for the dumping of concrete debris at the landfill site and then recycles it, selling this material as crushed concrete.

Samples were taken from the concrete stockpiles at the landfill after crushed concrete being used on a council project was suspected of containing asbestos.

Two of those samples found a low-level presence of asbestos. No asbestos was found in the crushed concrete at the project site.

Taupō District Council is following expert advice to guide its response to this situation and has been advised it will need to undertake an extensive sampling programme.

Of the twelve samples from the landfill stockpiles taken to date, ten have come back as safe and two samples have come back at the low end of the low level of contamination.

“The health and safety of our community is absolutely crucial, so we are following expert advice on how to manage the stockpiles, including keeping these stockpiles damp to prevent asbestos fibres getting into the air,” Council chief executive Julie Gardyne said.

She said that the concrete stockpiles are away from the main landfill operations and that with the watering system in place, the Council are comfortable with the fact that there is no risk to landfill staff or visitors. It has put concrete recycling at the site on hold, however.

“We know our community enjoys being able to take advantage of the affordable disposal of their concrete waste, but while this issue is being investigated, we want to keep everyone safe, so concrete is not currently being accepted for recycling.

“It can be disposed of as general waste at the general waste disposal price of $210 per tonne. We expect this may need to continue for some months.”

“We are taking a very cautious approach to managing this situation, and while we expect test results to continue to come back as safe or at low levels of contamination, we want to do everything we can to ensure we identify and dispose of any crushed concrete that could potentially pose a risk for the community.”

Anyone who has purchased crushed concrete from the Broadlands Road Landfill should call Taupō District Council on 07 376 0899 to arrange for appropriate testing. For more, go to www.taupo.govt.nz/concrete.

How Asbestos Enters Concrete

Typically, crushed concrete is used in the construction of roads and driveways, a simple way to recycle such material. But how does asbestos enter concrete at all?

Asbestos was common in buildings constructed before the 80s, across cement sheeting, pipes and insulation, and flooring adhesives and ceiling materials. When these buildings are demolished, the asbestos-containing materials (ACMs) can break apart and mix with concrete rubble.

Concrete from demolished structures is often crushed and recycled for use in new projects. If it’s not properly identified and removed during demolition, it can be inadvertently mixed into the concrete during recycling. This can lead to contaminated stockpiles.

In some cases, asbestos may not be detected before demolition due to insufficient inspection. During demolition, improper handling of asbestos materials can cause fibres to become airborne or embed into concrete rubble, leading to contamination.

Further, asbestos-containing materials may be mistakenly classified as non-hazardous waste if proper testing isn’t conducted, leading to unsafe disposal in stockpiles intended for reuse.

As such, pre-demolition surveys and asbestos testing are critical in identifying asbestos before any demolition or recycling activities. Trained professionals must remove asbestos before concrete demolition to ensure it doesn’t contaminate stockpiles. When asbestos is detected, following expert advice – just as the Taupō District Council has – is paramount.