Naturally Occurring Asbestos: The Risk That Catches Civil and Earthworks Projects Off Guard

Most people in construction think of asbestos as a building problem, cement sheet, pipe lagging, vinyl backing, all of it manufactured and installed by someone. Naturally occurring asbestos is different. It formed in the rock, and it's been sitting in the ground for a very long time waiting for someone to cut a road through it.

For civil, quarry and earthworks projects in the wrong geology, that's a live risk and one that rarely appears in the project risk register until it's already causing a problem.

Where NOA actually occurs

Naturally occurring asbestos, or NOA, is asbestos mineral that forms in rock through geological processes. In eastern Australia it turns up most often in serpentinite, ultramafic rock that's been altered over time, usually as thin chrysotile veins running through the rock mass. Central Queensland has known chrysotile-bearing ultramafic belts. So does the New England region of NSW, along the Great Serpentinite Belt. Deposits exist in every Australian state.

The point is not that these areas are dangerous to stand in. Undisturbed NOA generally isn't a health risk. The risk is created by the work: excavation, blasting, crushing, grading, hauling and anything else that breaks the rock up and puts dust in the air.

Why it catches project teams out

Three reasons, over and over.

The first is that a site history search won't find it. There's no former land use to flag, no demolition record, no imported fill to investigate. A site can be pristine bushland and still sit on top of an asbestos-bearing formation.

The second is that NOA doesn't look like asbestos. Fibrous veins in rock are easy to walk past, and even where they're visible, confirming the mineralogy takes laboratory analysis. Field judgement isn't enough.

The third is that the usual playbook doesn't apply. With a building, you find asbestos, you remove it, you get a clearance and you move on. You cannot remove a geological formation. NOA has to be managed in place, dust suppression, exclusion zones, air monitoring, controlled handling and haulage, and a management plan that holds up under scrutiny.

That last point is where programs get hurt. A team geared up to remove a hazard discovers the hazard is the site itself, and works stop while everyone figures out what to do.

Getting ahead of it

Under WHS regulations, once asbestos is identified or is likely to be present, you have a duty to manage it, which means an asbestos management plan and controls appropriate to the work. The regulatory obligation isn't the hard part. The hard part is finding out about it in week 12 instead of week zero.

Recent roadworks in regional NSW show how differently this plays out with early information. NOA was confirmed in samples taken before major works, and the design approach shifted, resurfacing over the existing pavement rather than excavating into material that would have needed extensive controls and disposal. Same road, far less disruption, because the sampling happened first.

That's the version we want for our clients. Assess the geology and the proposed disturbance early, sample where the risk is real, and build the controls into the methodology and the program rather than bolting them on under pressure. Regulations don't have to slow a project down. Discovering things late does.

The practical takeaway

If your project involves ground disturbance in an area with ultramafic or serpentinite geology, road corridors, quarries, pipeline routes, bulk earthworks, regional infrastructure, get NOA screening into the early works assessment. It's a small cost against the alternative, which is a stopped site and a management plan written in a hurry.

We physically sample suspect material rather than presuming what it is, and we stay involved through monitoring, controls and sign-off rather than handing over a report and disappearing.

Talk to the BBN team about your next project. We'll tell you whether NOA is a real risk on your site or not, and either answer is useful.