Alert Raised in Sydney over Asbestos-Contaminated Mulch

Photo credit: The Conversation

Mulch containing asbestos has been found at 41 locations in New South Wales, including Sydney parks, schools, hospitals, a supermarket and at least one regional site. Tests are under way at other sites, according to recent news reports.

As a precautionary measure, some parks have been cordoned off and some schools have closed temporarily. Health authorities have warned the public to steer clear of the contaminated areas, which have been cordoned off.

Extended exposure to asbestos – which was once widely used in construction materials – can lead to a form of cancer called mesothelioma or the chronic lung disease asbestosis. The related illnesses take years, sometimes decades, to develop and there is generally no testing for people who might have been exposed in the short term.

Asbestos is most dangerous when inhaled over an extended period, health officials say. (Getty Images via BBC)

Australia began phasing out asbestos in the 1980s and banned it in 2003.

What are the Health Risks of Asbestos?

This park in Sydney suburb Chippendale is one of the sites affected. (EPA via BBC)

Asbestos is a naturally occurring, heat-resistant fibre that was widely used in building materials from the 1940s to the 1980s. It can be found in either a bonded or friable form.

Bonded asbestos means the fibres are bound in a cement matrix. Asbestos sheeting that was used for walls, fences, roofs and eaves are examples of bonded asbestos. The fibres don’t escape this matrix unless the product is severely damaged or worn.

A lot of asbestos fragments from broken asbestos products are still considered bonded as the fibres are not released as they lay on the ground.

Photo credit: EPA via BBC

Friable asbestos, in contrast, can be easily crumbled by touch. It will include raw asbestos fibres and previously bonded products that have worn to the point that they crumble easily.

The risk of disease from asbestos exposure is due to the inhalation of fibres. It doesn’t matter if those fibres are from friable or bonded sources.

However, fibres can more easily become airborne, and therefore inhalable, if the asbestos is friable. This means there is more of a risk of exposure if you are disturbing friable asbestos than if you disturb fragments of bonded asbestos.

Who is Most at Risk from Asbestos Exposure?

The most important factor for disease risk is exposure – you actually have to inhale fibres to be at risk of disease. Just being in the vicinity of asbestos, or material containing asbestos, does not put you at risk of asbestos-related disease.

Asbestos sheeting was used for walls and roofs. (Tomas Regina/Shutterstock via The Conversation)

For those who accessed the contaminated areas, the level of exposure will depend on disturbing the asbestos and how many fibres become airborne due to that disturbance. The risk of disease from exposure depends on the intensity, frequency and duration of that exposure. That is, the more you are exposed to asbestos, the greater the risk of disease.

Most asbestos-related disease has occurred in people who work with raw asbestos (for example, asbestos miners) or asbestos-containing products (such as building tradespeople). This has been a tragedy and fortunately asbestos is now banned.

There have been cases of asbestos-related disease, most notably mesothelioma – a cancer of the lining of the lung (mostly) or peritoneum – from non-occupational exposures. This has included people who have undertaken DIY home renovations and may have only had short-term exposures. The level of exposure in these cases is not known and it is also impossible to determine if those activities have been the only exposure.

Mulch contamination is not new. (gibleho/Shutterstock via The Conversation)

There is no known safe level of exposure – but this does not mean that one fibre will kill. Asbestos needs to be treated with caution.

What If I’ve Been Near Contaminated Mulch?

Exposure from mulch contamination is generally much lower than from current renovation or construction activities and will be many orders of magnitude lower than past occupational exposures.

Unlike activities such as demolition, construction and mining, the generation of airborne fibres from asbestos fragments in mulch will be very low. The asbestos contamination will be sparsely spread throughout the mulch and it is unlikely there will be sufficient disturbance to generate large quantities of airborne fibres.

Despite the low chance of exposure, if you’re near contaminated mulch, do not disturb it.

~ excerpts from The Conversation (19 February 2024) and BBC (20 February 2024))

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