What happens to asbestos-contaminated soil when it is removed?

As almost unbelievable as it might seem today, given the knowledge we now have of the serious risks asbestos poses to health, there was a time in the UK when it was very widely used as a construction material.

For much of the 20th century, the naturally occurring substance was incorporated into such common products as sprayed coatings, lagging, asbestos cement products, roofing felt, and asbestos insulating board.

By around the 1970s, however, awareness was increasing of the link between asbestos inhalation and the development of potentially fatal health conditions, such as mesothelioma, asbestosis, and asbestos-related lung cancer. Political pressure heightened from this point forward, until all forms of asbestos were finally banned in the UK in 1999.

At that stage, however, asbestos had come to be present in domestic, commercial, and public buildings up and down the UK. And when many such buildings came to be demolished in later years, the most responsible practices were not always followed in relation to the asbestos still contained inside.

Such a combination of circumstances has led to a situation where on many brownfield sites in the UK today, the ground has become contaminated with asbestos fibres.

But even if today, you are diligent about following all the stringent regulations in relation to asbestos on a site for which you are responsible, what do you need to know about what happens to asbestos-contaminated soil following removal?

What are the reasons for asbestos-contaminated soil removal?

If you come to be aware that soil on a site for which you are responsible is contaminated with asbestos, you might assume that the contaminated soil will need to be removed from the site, in order to keep people safe from disturbing and potentially breathing in the asbestos fibres.

However, the mere fact of asbestos being present on your land would not automatically mean that it would have to be removed. The decision that you make in this regard will depend on the nature and extent of the risk that any asbestos contaminated soil likely presents to the health of people nearby.

In order to determine that risk, you will need to arrange for a risk assessment to be carried out. This process can be undertaken by a suitably skilled and experienced environmental consultant with experience in relation to asbestos in soils.

It might emerge from the risk assessment that it is actually safe to leave the contaminated soil in situ, perhaps with a simple, clean cover system on the soil in question.

Alternatively, it might be determined from the risk assessment that there are unacceptable risks likely to necessitate removal of the asbestos-contaminated soil. The decision is therefore often made to remove the asbestos-contaminated soil in certain circumstances – for example, when construction or demolition is to take place on the site, or as part of environmental remediation efforts.

However, if the decision is instead made to leave the asbestos-contaminated soil in place, this does mean it will need to be managed on an ongoing basis, with all the associated risks. The type, extent, and condition of the asbestos will determine those risks.

The level of risk with ongoing management will also hinge on the usage of the land in question. If the land is not built on or disturbed, any asbestos-contaminated soil would pose only a limited risk.

Much will also depend, though, on the depth of the asbestos materials. In the event of the asbestos materials being near the surface of the soil or land, it may be necessary to have the area sealed with a membrane, and capped with clean soil or material. This will protect the asbestos and prevent it from being accidentally disturbed during normal use of the site.

What is the process that needs to be followed for asbestos-contaminated soil removal?

There are various steps typically involved in the removal of asbestos-contaminated soil, including site assessment, soil sampling, excavation, transport, and disposal. However, the exact process and requirements for disposal will depend on the specific regulations and guidelines for the location that the contaminated soil is being removed from.

As a first step, you should be arranging for a full risk assessment, which will enable you to determine whether the task of removing the asbestos-contaminated soil will require an asbestos licence. The depths of the asbestos in the soil will dictate the volume of the soil or material that will need to be removed, and the asbestos contaminated land survey will provide the details on this.

With asbestos being the highly dangerous substance that it is, certain safety precautions must also be taken during the removal process. These include the wearing of appropriate personal protective equipment, and the use of specialised equipment and techniques to minimise the scope for asbestos fibres to be released.

The following are essential elements of the process of removing asbestos-contaminated soil:

• Contaminated areas need to be restricted by barriers
• Water cannons should be used to suppress asbestos fibres during the works
• Appropriate respiratory protective equipment (RPE) and personal protective equipment (PPE) are essential
• Waste Acceptance Criteria (WAC) testing will need to be carried out, before a decision is made on the final location of soil or material disposal or cleaning

There are generally two options available in relation to the treatment and/or disposal of asbestos contaminated soil.

The first involves the physical removal of the contaminated soil where the soil is excavated  and then transported to a specialised disposal facility. These facilities are specifically designed for the safe storage and further treatment of the asbestos-containing materials. These registered landfill sites are designed to prevent asbestos fibres from being released into the air or water, and they must comply with strict regulations and monitoring requirements. Before soil can be sent to landfill, WAC testing is required to ascertain the makeup of the asbestos-containing material.

The second available option involves the washing and cleaning of the asbestos-contaminated soil and is again a highly-regulated process. This process is also known as soil remediation or soil decontamination. Soil washing involves the removal or reduction of asbestos fibres from the soil which subsequently reduces the risk of asbestos exposure.

The soil washing process typically involves the following. Firstly, the contaminated soil is excavated from the site and screened to remove large debris and rocks. The soil is then processed through a shredder or crusher to break it down into smaller particles, which helps in the subsequent separation process. The soil is mixed with water and subjected to vigorous agitation in a soil washing unit. This process helps to dislodge and suspend the contaminants, including asbestos fibres, in the water. The soil-water mixture is then passed through a series of screens or sieves to separate the larger soil particles from the smaller suspended contaminants, including asbestos fibres.

In some cases, chemical additives may be used during the washing process to enhance the separation of contaminants. These chemicals can help in breaking down or binding the asbestos fibres, facilitating their removal from the soil.

Finally, the water used in the washing process, containing suspended contaminants, is treated to remove the asbestos fibres and other pollutants before it is discharged or reused. Treatment methods may include settling tanks, filtration systems, or chemical treatment processes.

It’s important to note that soil washing is not always suitable or effective for all types of asbestos-contaminated soil. Factors such as soil composition, asbestos concentration, and site-specific conditions need to be considered. Consulting with licensed asbestos remediation professionals or environmental consultants is recommended to determine the most appropriate and effective remediation method for your specific situation.

Even if you arrange for the removal of asbestos-contaminated soil from a site for which you are responsible, following this operation, there may still be a degree of asbestos contamination on the site. This would necessitate ongoing monitoring and maintenance of the site, to ensure the proper management of any remaining contamination, and to prevent future contamination.

Such proactive management of any remaining asbestos may include ongoing monitoring of the soil and water quality, as well as regular maintenance of any barriers or other measures that are used to prevent exposure to asbestos fibres.

Overall, it is crucial to make sure any removal and disposal processes for asbestos-contaminated soil on your land are carried out in a proper and safe manner. This will help to protect public health and the broader environment, while aiding your compliance with appropriate regulations and guidelines.

The transport and disposal of asbestos-contaminated soil

As you can imagine given the dangers that asbestos-containing materials can present, there are various regulations and guidelines that must be followed in relation to the transportation and disposal of asbestos-contaminated soil.

The exact regulations and guidelines that apply, will depend on the location from which the soil is being removed. Nonetheless, there is no doubt about the importance of doing everything possible to ensure the safety of workers and the surrounding community, when it comes to any operation involving the handling of asbestos.

Transportation of asbestos-contaminated soil

The transport vehicles that are used to remove asbestos-contaminated soil, are typically required to be closed or covered, to help prevent the release of asbestos fibres into the air. In addition, drivers and other personnel that are involved in the transportation process may be expected to undergo specific training, so that they are suitably aware of asbestos-related risks.

Disposal of asbestos-contaminated soil

Once the asbestos-contaminated soil arrives at the disposal facility, it is typically unloaded and placed in a designated disposal area that is specifically designed to prevent asbestos fibres from being released into the environment.

Specialised equipment and procedures are typically used at such facilities to guard against the release of any asbestos fibres into the air or water. There may also be a need for ongoing monitoring and maintenance of the disposal area.

Such exacting standards at facilities like these are – of course – practised to help minimise the risk to human health. However, it also helps that disposal facilities that accept asbestos-containing materials are typically subject to stringent regulations and monitoring requirements.

Is any aftercare and monitoring required?

Even following the completion of an asbestos removal operation from land where contaminated soil was present, further survey works are usually carried out at the site where the contamination was originally found. This process enables those responsible for the site to ensure that all traces of asbestos have been fully removed.

If this survey shows that no asbestos remains at your site, your work will be done; no further action will be required. In the event, however, of additional contamination being found, the removal process can continue until a survey indicates that all contamination has been removed.

Alternatively, as we touched on above, you may decide – depending on the circumstances – to leave any remaining contamination in place, provided that it is safe for you to do so. But even if you do take this path, it will still be necessary for you to ensure the proper management of that remaining contamination, including by arranging for periodic site reassessment and ongoing monitoring.

Are you doing enough to manage asbestos risks on your own site?

Hopefully, our guide will have helped you to feel more informed about the process of removing asbestos-contaminated soil from a given site, and what happens to that contaminated soil with regard to removal and disposal.

You should also now be aware of the importance of taking proactive steps in response to suspected asbestos on land for which you are responsible. Such steps should include arranging for a risk assessment and asbestos-contaminated land survey, as well as any necessary ongoing management and monitoring after removal.

Adopting all of these measures for your site, where appropriate, will ensure you are doing everything possible to stay in compliance with the law, at the same time as protecting public health.

Do you have any questions with regard to your management of a site where you suspect or know asbestos-containing materials to be present? If so, please feel free to reach out to the Oracle Solutions team by email, or to give our team a call.