This time in our Contaminant Focus series, we are looking at asbestos. Due to its thermal, electrical and corrosion resistance properties, asbestos was commonly used in many traditional industries for thermal insulation around pipes and boilers and was also used in building products. As a result, it is commonly found in older buildings and also in soils/made ground on brownfield sites where buildings associated with former industries have been demolished before regulations to control asbestos were brought in and enforced. Additionally, because of the high costs involved in the safe handling and disposal of asbestos containing materials (ACM), it is not uncommon to find them fly-tipped on vacant land, so even greenfield sites can still potentially be contaminated by asbestos.
What is Asbestos?
Asbestos is a naturally occurring, fibrous mineral found in certain metamorphic rocks. Asbestos has strong elongated fibres, and its physical properties including fire and chemical resistance, led to its widespread use in a huge range of materials. The three main types of asbestos which were most widely used are Chrysotile (a serpentine asbestos), Amosite and Crocidolite (both amphiboles).
Why is Asbestos Dangerous?
Airborne asbestos fibres can become embedded in the lungs if inhaled, and today it is widely known that asbestos exposure is associated with respiratory diseases, including a rare type of lung cancer called mesothelioma – although the tumours may not develop until decades after exposure. The link between asbestos and cancer was established in the 1930’s, many years after its use became popular during the Industrial Revolution. Yet despite this, the use of asbestos not only continued but actually increased into the 1970’s. It wasn’t until 1985 that a partial ban on asbestos was established in the UK, followed by a full ban in 1999.
In addition to mesothelioma, prolonged exposure to asbestos fibres can cause a lung condition called asbestosis, where the fibres cause inflammation and scaring of the lungs. Many people who suffered from this condition worked in asbestos mining or manufacturing industries where they had daily exposure to asbestos dust, but their families often also suffered from it too due to second-hand exposure from dust brought home on clothing.
Today, even though the use of asbestos has been banned, it still poses a risk due to its presence in older buildings – including homes, schools and hospitals. Although asbestos fibres bound within construction materials generally pose a low risk, when they are disturbed by occupants or during maintenance/demolition work, the fibres can be released. Because there is no safe level of exposure to asbestos, care needs to be taken to avoid any exposure to fibres and contaminated dust.
Most asbestos remediation work is related to removal of asbestos products from older buildings, either prior to demolition, or where it has been found to present a danger to the building’s occupants. However, where older buildings were demolished before regulations were brought in, it is not uncommon to find ACM contamination in soil and made ground as well and it's at this stage that ERS usually becomes involved.
How is Asbestos Remediated?
All work with asbestos containing soils is subject to the Control of Asbestos Regulations (CAR) 2012, and CAR-SOIL guidance. Depending on factors including ACM type and condition, work involving disturbance of asbestos may be licensed, or non-licenced.
Due to our experience in investigating and remediating contaminated land and post-industrial brownfield sites, ERS has considerable expertise in the treatment and removal of non-licensable levels of ACM contamination in soils.
Our non-licensed asbestos services include:
• Provision of risk assessments and specialist support/supervision
• Remediation earthworks for asbestos containing soils
• Mechanical screening, hand picking
• Asbestos waste characterisation
• Appropriate handling and disposal of asbestos waste
Remedial options depend on the client’s budget, the proposed land use, the site conditions, the type(s) of ACM present and the concentration in the soil. All works involving disturbance of asbestos are planned and undertaken in accordance with CAR-SOIL. A pre-works risk assessment is required to determine the licensing status of the planned works, and the appropriate control measures and procedures, which may include dampening down to prevent fibre release, and air and dust monitoring.
Some of Our Asbestos Remediation Projects:
Contaminated Made Ground Removal at Former School Site
A considerable amount of asbestos contamination had been discovered in made ground at a former school being redeveloped for housing and a care home. ERS undertook screening and hand picking so that clean material could be reused on-site as back-fill under a capping layer. The remaining contaminated material was taken to an appropriate, licenced facility. Real-time air monitoring and dust mitigation were employed to protect local residents and site staff.
You can read more about this case study here.
Contaminated Soil Removal at Former Hospital Site
Asbestos contamination had been identified at a residential development at a former hospital in Scotland, including free fibres. ERS was appointed by the developer to undertake wider remediation of the site, which was also impacted by hydrocarbon contamination. We undertook a pre-works risk assessment, which concluded removal of the ACM contamination hotspots was notifiable non-licensed work, with less contaminated areas meeting the criteria for non-licenced work. The contamination was then delineated and excavated, with material from the hotspots sent for disposal at a suitably licensed facility and the less contaminated material covered for reuse on site underneath capping layers and hardstanding. Appropriate decontamination and risk minimisation procedures were employed during all works, including dust suppression and air monitoring.
Contaminated Soil Removal at Confidential Site
Asbestos is an emotive subject. Sometimes the perception of risk can be more important that the real risk. This was the view of one client at a confidential site in Inverness. Despite having agreement from the Contaminated Land Officer and SEPA to reuse asbestos contaminated crushed demolition material at depth on site, our client decided that the risk of its retention causing alarm to prospective house buyers was too great. ERS was employed to safely excavate, haul and dispose of 2,000 tonnes of material under the strictest of dust prevention and monitoring regimes to ensure the site was clear of all asbestos.