Asbestos in Soil: What Happens After the Lab Result

Asbestos in soil becomes hazardous waste above 0.1% by weight, or where asbestos debris is visible regardless of the measured percentage. Between 0.001% and 0.1% it is not hazardous waste, but the Control of Asbestos Regulations 2012 still apply and control measures are still required. Below 0.001%, CAR 2012 does not apply.

Those figures come from a ground investigation carried out by an environmental consultant working with a UKAS accredited laboratory. This article covers what happens next: what the numbers mean for your programme, when the works become licensed, and what your options are for the material.

How Does Asbestos End Up in Soil?

Almost always through historic construction rather than anything geological. Demolition waste buried on site instead of removed. Crushed demolition material reused as recycled aggregate. Legacy contamination from former industrial sites and manufacturing plants. Undocumented disposal in historic landfills. Asbestos cement used to make up farm tracks and paths. It still happens today through fly-tipping and imported fill that turns out not to be clean.

The practical consequence is that brownfield land, made ground and anywhere with a pre-2000 building history should be treated as potentially contaminated until an investigation says otherwise. What comes out of the ground is rarely intact. Asbestos insulating board, thermal insulation debris and asbestos cement fragments broken up and distributed through rubble behave very differently to a sheet of AIB fixed to a ceiling, which is why asbestos in soils is scoped and priced differently to building removal work.

What Do Asbestos in Soil Thresholds Mean in Practice?

The middle tier is the one that causes most confusion. Soil between 0.001% and 0.1% is not hazardous waste, which means it does not carry hazardous waste disposal costs or consignment requirements. It is still asbestos contaminated soil, it still falls under CAR 2012, and work with it still requires trained operatives, a proper method of work and control measures. Not hazardous is not the same as not regulated, and treating it that way is how sites end up with enforcement problems.

Two other points are worth knowing before you read a report. Visible asbestos debris classifies the material as hazardous regardless of the measured percentage, so a site can return low figures and still be hazardous. And a single percentage is an average across sampled material, not a uniform description of the whole site: contamination is usually concentrated in some areas and absent in others, which is what determines whether you excavate everything or sort selectively. CIRIA C733, the industry guide to understanding and managing asbestos risk in soil and made ground, is the reference most consultants will be working to when they set out those findings.

When Does Asbestos in Soil Become Licensed Work?

It depends on the material, not on the soil.

Asbestos insulating board and thermal insulation debris are licensable. Where those are present and will be disturbed, the works must be carried out by an HSE-licensed contractor, they are notifiable, and a 14-day notification period applies to the HSE before they can legally begin. Asbestos cement debris is usually non-licensed, but still requires trained operatives and controlled conditions. How CAR 2012 applies specifically to soil and demolition materials is set out in CL:AIRE's CAR-SOIL guidance, which includes decision support tools for categorising the works.

Contaminated ground routinely contains a mixture of all three. On two land parcels Emchia remediated in West London, the materials identified across twenty acres were thermal insulation debris, asbestos insulating board and asbestos cement debris together. That mixture is normal, and it is why a licensed contractor is usually the safer appointment even where the headline figure looks low.

The point to carry into a programme is that the 14-day notification sits ahead of the works. It does not run alongside enabling works and it does not compress when the start date moves.

Does Asbestos Contaminated Soil Have to Leave the Site?

No, and this is where the cost difference on a large scheme is usually made.

There are four routes: excavation and disposal to a licensed facility, sorting to reduce contamination levels within the soil, containment beneath a capping layer, and retention and reuse under a Materials Management Plan. Where a plan is in place and the material meets the criteria set out in CL:AIRE's Definition of Waste Code of Practice, soil can be retained and reused in earthworks rather than classified as waste. Every tonne that stays is a tonne not paid for in disposal, transport and landfill tax, and a tonne of clean fill not bought in to replace it.

Retention is not a shortcut. It has to be agreed with the enforcing authorities, its location and extent recorded, and it has to be managed for as long as it remains. It does not suit every contamination type or every development. But it should be assessed before defaulting to excavation and disposal, because on a site of any size that decision is worth more than anything else on the remediation budget.

Which route makes sense depends on how the soil asbestos is distributed, what the land is being used for, and what the remediation strategy commits to. Our asbestos land remediation service sets out how each is delivered on site.

What About Asbestos Disturbed During a Ground Investigation?

This is the case that catches people out, because the disturbance happens before anyone has a remediation strategy.

Drilling and piling on former landfill or industrial land brings buried asbestos to the surface. At that point the investigation contractor needs licensed asbestos cover already in place, not arranged afterwards.

RSK Group appointed Emchia as Licensed Asbestos Removal Contractor on a £167,000, twelve-week programme covering ground investigations across a former asbestos landfill in West Yorkshire, a site permitted to accept up to 25,000 tonnes of asbestos a year when operational. The works penetrated contaminated cells in around thirty locations, in places to fifty metres deep. Emchia arranged asbestos medicals, face fit testing and site-specific training, and supplied the PPE and RPE used by RSK's own drilling operatives.

If you have a ground investigation planned on land with a landfill or industrial history, the licensed cover, the notification period and the medicals all need lead time. It is worth raising before the programme is fixed.

Talk to Us About a Contaminated Site

Emchia is an HSE-licensed asbestos removal contractor working on land remediation across the North West, Yorkshire, the Midlands and London. If you have investigation findings, a remediation strategy or planning conditions, send them over and we will come back with a scope and a programme.

Frequently Asked Questions

At What Level Is Asbestos in Soil Classed as Hazardous Waste?

Above 0.1% by weight, or where asbestos debris is visible in the material regardless of the measured percentage. Between 0.001% and 0.1% the soil is not classified as hazardous, but CAR 2012 still applies and control measures are still required. Below 0.001%, CAR 2012 does not apply.

Do You Need a Licensed Contractor for Asbestos in Soil?

It depends on the materials present. Asbestos insulating board and thermal insulation debris are licensable, so work disturbing them requires an HSE-licensed contractor and a 14-day notification to the HSE. Asbestos cement debris is usually non-licensed but still requires trained operatives and controlled conditions. Because contaminated ground commonly contains a mixture, a licensed contractor is generally the safer appointment.

Can Asbestos Contaminated Soil Be Reused on Site?

Yes, in some cases. Where a Materials Management Plan is in place and the material meets the criteria, soil can be retained and reused in earthworks rather than classified as waste. It must be agreed with the enforcing authorities, its location and extent recorded, and it must be managed for as long as it remains on site.

Who Is Responsible for Asbestos Found in Soil During a Development?

Responsibility sits with whoever controls the site, usually the landowner or the developer carrying out the works, for ensuring the material is dealt with safely and in line with CAR 2012 and waste legislation. Liability for the original contamination is a separate question, generally addressed through the site's history and the sale contract.

What Happens If Asbestos Is Found Unexpectedly During Groundworks?

Work in the affected area should stop until the material is assessed by a competent specialist. Continuing risks exposing operatives and spreading contamination across the site, which makes the eventual remediation larger and more expensive.