What is an Asbestos Retrospective Risk Assessment (RRA)?

An Asbestos Retrospective Risk Assessment’ provides an objective understanding for employees and others to unintended occupational exposures to asbestos that may occur within the workplace. These exposures can give rise to concern and anxiety for those involved. Incidents and accidents that result in the exposure of employees and others to airborne respirable asbestos fibres all have the potential to increase, to some extent, the likelihood of developing an asbestos related disease. However, the extent of that risk is unlikely to be understood by either the individuals who have been exposed or the persons informing them of this.

By undertaking an Asbestos Retrospective Risk Assessment IOM can assess the possible exposure to asbestos that may have occurred and provide an estimate of dose in conjunction with a quantitative calculation of the future risk of developing an asbestos related disease. By providing a quantitative estimate of risk an RRA can provide re-assurance to employers and employees in single incidents but should not divert attention from legal duties. 

When would you need Asbestos Retrospective Risk Assessment?

The accidental release or escape of asbestos fibres into the air in a quantity sufficient to cause damage to the health of any person is reportable under RIDDOR. Such situations are likely to occur when work is carried out without suitable controls, or where those controls fail. 

An Asbestos Retrospective Risk Assessment will also be useful if your organisation is the focus of an intervention by a regulator, or if an employee, (past or present) has made a complaint. 

They can be used to assess the requirement for remediation work and are sometimes utilised in civil litigation cases. Although we may find that the risk from an individual incident is low, our reports will also affirm the importance of preventing repetition of such incidents. 

What type of work activities create a significant concentration of asbestos fibres in the air?

A number of work activities are more likely to create a significant concentration of asbestos fibres in the air, and therefore, add to the risk if suitable precautions are not in place; for example: 

  • use of power tools (to drill, cut etc.) on most ACMs 
  • work that leads to physical disturbance (knocking, breaking, smashing) of an ACM that should only be handled by a licensed contractor e.g. sprayed coating, lagging, asbestos insulating board (AIB) 
  • manually cutting or drilling of AIB 
  • work involving aggressive physical disturbance of high-density asbestos products e.g. breaking or smashing asbestos cement building materials

How do we evaluate asbestos exposure?

Our investigations normally consist of four stages: 

Stage one: First, we gather information about the specific incident. 

Stage two: We estimate concentrations of asbestos in the air using published scientific literature, our own extensive practical experience and any existing air concentration measurements. 

Stage three: The exposure of the individual(s) is estimated from the duration of exposure and the estimated concentration in the air. 

Stage four: The risk of developing lung cancer and mesothelioma are derived from the estimated exposures using widely accepted exposure-response models, which take age, gender and smoking into account. 

IOM's incident reports

Our incident reports provide evidence of any future risks of developing disease or risk to health based on individual exposures and could prevent an unnecessary prosecution.  

Our carefully constructed, authoritative reports provide the best possible estimates of risk and are tailored to each individual situation. They describe the methods used, the sources of information and the estimated risks of cancer. The estimated risks are always put in to context by comparing the asbestos related risks with common hazards such as smoking or road accidents, as well as benchmark levels of risk used by some authorities to define "acceptable" levels of risk. 

We have applied this approach to determine the levels of exposure and risks: 

  • to personnel unknowingly disturbing asbestos in commercial and public buildings;  
  • from the disturbance of fragmented asbestos materials on rights of way;  
  • from the inadvertent disturbance of asbestos containing materials during maintenance, refurbishments and demolition works; and  
  • from the disturbance of asbestos contaminated soils. 

If the risks are low, our reports provide reassurance to staff or public. They can also help employers focus on preventative measures and management controls. 

Our reports are also vital in helping an employer to decide if a case needs to be reported under RIDDOR. Changes to the sentencing guidelines introduced in 2010 have seen penalties for asbestos prosecutions increase. Penalties which can’t be ignored. In 2016-17, the HSE prosecuted over 200 asbestos cases in the construction sector with an average fine of £77,000. 

How do I understand the risks from contaminated land?

Using a similar approach for contaminated land risk assessments we can help assess risks from potential past exposures through use of asbestos contaminated sites or asbestos contaminated material. We can also help assess how best to deal safely with soil that is contaminated with asbestos, and to determine whether "significant possibility of significant harm" (SPOSH) exists under Part IIA of the Environmental Protection Act 1990.  
 
IOM reports provide organisations with the rational technical basis for either the developer to assess and demonstrate whether a site is "safe and suitable for use", or the Local Authority to inform their decision as to the condition of land under Part IIA. 

What type of work activities create a significant concentration of asbestos fibres in the air?

Some work activities are more likely to create a significant concentration of asbestos fibres in the air, and therefore, add to the risk if suitable precautions are not in place; for example:

  • use of power tools (to drill, cut etc.) on most ACMs (asbestos-containing materials);
  • work that leads to physical disturbance (knocking, breaking, smashing) of an ACM that should only be handled by a licensed contractor e.g. sprayed coating, lagging, asbestos insulating board (AIB)
  • manually cutting or drilling of AIB
  • work involving aggressive physical disturbance of high-density asbestos products e.g. breaking or smashing asbestos cement building materials

 

How do we evaluate asbestos exposure?

Our investigations normally consist of four stages:

  • Stage one: First, we gather information about the specific incident.
  • Stage two: We estimate concentrations of asbestos in the air using the scientific literature, our own extensive practical experience, any existing air concentration measurements and/or our own measurements.
  • Stage three: The exposure of each individual is estimated from the duration of exposure and the estimated concentration in the air.
  • Stage four: The risks of contracting lung cancer and mesothelioma are derived from the estimated exposures using widely accepted exposure-response models, which take age, gender and smoking habits in to account.

 

How do I understand the risks from contaminated land? Assessment of risk from asbestos in soils

We have used a similar approach to contaminated land risk assessments concerning asbestos. This work has been undertaken to help assess risks from potential past exposures through use of contaminated sites, as well as to help assess how best to deal safely with soil that is contaminated with asbestos, and to determine whether "significant possibility of significant harm" (SPOSH) exists under Part IIA of the Environmental Protection Act 1990.

Our reports provide the rational technical basis for either the developer to assess and demonstrate whether a site is "safe and suitable for use", or the Local Authority to inform their decision as to the condition of land under Part IIA.

One of the difficulties in determining the risks associated with asbestos-contaminated soils is that the contamination is typically very variable within distances of only a few metres. Asbestos is only dispersed in the soil through mechanical mixing and there is an element of chance as to whether samples collected from soils containing discrete fragments of ACMs do or do not contain asbestos. It is therefore important that sufficient samples are collected and analysed in order to develop an understanding of the distribution of asbestos contamination and to properly determine the quantity present as this will have a significant impact on the determination of potential risks to health and future management. It is also important that if there are large fragments of ACMs present that their inclusion in the determination of soil asbestos content, is as part of an appropriately large sample.

Part of the risk assessment would include advice on how to manage the exposure risks when undertaking the proposed remediation/redevelopment works.

If you have any questions you can contact the team on: ExpertWitness@iom-world.org

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Latest News & Insight

Events
20 October
2021
In partnership with the ICBA

Particles and Health 2021

  • 20 October 2021
  • Running from the 20.10.21 to 21.10.21

IOM is proud to be sponsoring the Particles and Health conference, a two day event designed for regulators and researchers to:

  • Address scientific studies regarding human health effects of PSLTs. The value of human studies over animal studies-when human-exposed populations can be studied adequately- will be emphasized.
  • Review and discuss definition of PSLT’s proposed at Edinburgh workshop and published in 2020 in the Journal Inhalation Toxicology with attention to both similarities and differences among these substances.
  • Address translational toxicology challenges, including the appropriateness of rats as models for human lung pathogenesis (particularly lung cancer) in light of lung overload phenomena and species differences.
  • Serve as a platform to present current scientific information about PSLTs important for regulatory action.
  • Publication of pertinent conference presentations in the peer reviewed scientific literature will allow the presentations to live beyond the conference and subsequently be reviewed part of regulatory deliberations.
  • Establish an interdisciplinary setting for industry, academia and regulatory professionals to interact on an important topic. Such interaction can facilitate enhanced understanding of the science and appropriate classification, labelling and setting exposure limits, among others.
  • Recommend areas for further research regarding the significance of the rat as a model for translation toxicology. 
  • Review the biokinetics of inhaled nanoparticles and the potential for non-pulmonary effects.

For more information and tickets please visit the Particles and Health website here.

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