Good Practice Guidance for the Management and Control of Asbestos

Protecting Workplaces and Communities from Asbestos Exposure Risks

• Publisher: Asian Development Bank
• Year: 2022
• ISBN:
  9789292693718
• Topic: Medicina
• Subtopic: Sanità, amministrazione e assistenza pubblica

All forms of asbestos are considered carcinogenic to humans. However, around 125 million people globally are exposed to asbestos in the workplace, with an estimated 233, 000 deaths every year attributed to the inhalation of airborne asbestos fibers. This publication aims to increase awareness of the health risks associated with asbestos in the workplace and provides recommendations and checklists on avoiding and managing the risks of exposure. It covers the duties of employers and contractors; training requirements; and the identification, containment, safe removal, and management of asbestos waste.

1  INTRODUCTION

Asbestos is a fibrous silicate mineral that became widely used in the 20th century due to its tensile strength, thermal stability, thermal resistance and electrical resistance. The World Health Organization (WHO) considers all forms of asbestos to be carcinogenic to humans. While mining, manufacturing and use of asbestos-containing material (ACM) continues in many parts of the world, more than 60 countries globally have banned the use of asbestos due to its human health impact with respect to development of asbestosis, asbestos-related lung cancer, and mesothelioma.

1.1  The Purpose of This Good Practice Guidance

The purpose of this Good Practice Guidance (GPG) is to help increase awareness of the risks of occupational asbestos exposure and of how to address them. It provides high level guidance on:

•  The duties of employers, workers/subcontractors, asbestos contractors and vendors;

•  Training requirements for working with asbestos;

•  Identification of asbestos;

•  Managing long term risks of asbestos;

•  Working safely with asbestos;

•  Managing incidents where asbestos is found;

•  Managing the risks of asbestos removal;

•  Managing asbestos waste; and

•  Managing asbestos waste generated through disasters

This Good Practice Guidance is not intended to provide a detailed methodology for performing work where asbestos is present. It is recommended that specialist advice be sought to provide a situation-specific detailed methodology and ensure compliance with relevant national legislation and other international best practice requirements.

The International Labour Organization (ILO) and the WHO provide guidance (ILO & WHO, 2007) that states that asbestos-containing material should be avoided in new construction. In existing projects, the presence of asbestos and associated asbestos risks should be assessed and a management plan be prepared that includes the end-of-life actions.

This document considers good practice guidance prepared by international organizations, including the ILO (1984) Safety in the Use of Asbestos and the World Bank (2009) Good Practice Note: Asbestos: Occupational and Community Health Issues (links provided in Section 13). Other international documents were used to supplement these guidance documents.

As an additional tool, Appendix B includes checklists to help implement this good practice guidance. These provide a useful summary of important items that may be addressed to:

•  Minimize the use of asbestos in any new developments.

•  Identify general duties of workers and project managers/employers.

•  Confirm that workers involved in projects are appropriately trained to perform asbestos work.

•  Ensure that asbestos has been identified and that asbestos management plans are in place.

•  Manage the risk of asbestos.

•  Manage asbestos-related work.

•  Manage asbestos incidents.

•  Ensure that asbestos removal work is being conducted in a safe manner.

•  Check that asbestos waste has been appropriately handled and disposed of.

•  Manage asbestos during disasters.

Appendix B also provides a list of suggested key performance indicators and associated documentary evidence which may be used to monitor the safety components of asbestos work.

2 ASBESTOS AWARENESS

2.1 What Is Asbestos?

Asbestos is a naturally occurring fibrous serpentine or amphibole mineral with current or historical commercial usefulness due to its extraordinary tensile strength, poor heat conduction and relative resistance to chemical attack (WHO, 2014; IARC, 2018).

Asbestos is often categorized in two main classes:

• Serpentine, which consists of a silicate with the hydroxyl layer on the outside and forms curly and snake-like fibers. This class includes the chrysotile form of asbestos.

• Amphibole, which consists of a silicate with a hydroxyl layer on the inside and can be recognized by the sharp needle-like fibers. This class includes the crocidolite, amosite, anthophyllite, tremolite, actinolite, riebeckite, and cummingtonite-grunerite forms of asbestos.

Three of the abovementioned asbestos minerals that are regularly encountered in commercial products include the following (shown in Image 1):

• Chrysotile (white asbestos);

• Amosite (brown asbestos); and

• Crocidolite (blue asbestos).

Image 1: Most Common Forms of Asbestos

Source: iStock.com.

The most common forms of asbestos encountered are chrysotile and amosite asbestos. It is rare to find pure form asbestos as a commercial product.

2.2 Asbestiform Habit

Asbestiform habit is a term that is used to describe the crystallization form of a mineral consisting of crystals that are thin, hairlike fibers that possess enhanced strength, flexibility and durability and lack of surface defects (National Research Council (US) Committee on Nonoccupational Health Risks of Asbestiform Fibers, 1984).

In addition to asbestos, there are other minerals used in industry (e.g., palygorskite), which may also crystallise with well-developed thin hairlike fibers (i.e., in the asbestiform habit) but are not called asbestos. These minerals may also have properties similar to asbestos and pose similar hazards.

2.3 Where Can Asbestos Be Found in the Workplace?

Because of its tensile strength, durability and fire and chemical resistance, asbestos has been used for thousands of years. Widespread use did not occur until major asbestos mines were opened in the 1880s. Historians estimate that asbestos has been used in more than 3000 types of products in consumer goods (insulation, thickeners and fillers) and in construction, maritime and automotive industries.

In recent years, the main asbestos products comprise corrugated fiber cement (roofing), flat fiber cement, pipes, insulation, friction materials, gaskets and joints and textile and sealants.

Due to its extensive use historically, asbestos may be present in many parts of the built environment, including walls, ceilings, roofs, floors, pipes, electrical switchboards, heaters, boilers, roof and wall cavities, pipe joints, etc. Examples of uses are provided in Section 6.1.

Asbestos can also be found in contaminated soils around buildings or structures containing asbestos due to deterioration of the asbestos-containing materials, or where poor demolition of buildings or structures with asbestos-containing materials has occurred.

As asbestos (and other asbestiform minerals) are naturally occurring, asbestos may be encountered as naturally occurring minerals at some project locations, such as in tunnel digging/boring, excavation for buildings or infrastructure, etc. Where a national register exists on potential locations of naturally occurring asbestos and other asbestiform minerals, it is prudent to assess whether proposed project related work is likely to expose these minerals.

2.4 What Is the Difference between Bonded and Unbonded Asbestos?

Asbestos is commonly encountered as a commercial product in two forms (Image 2) based on the potential for releasing fibers, and the associated risks to human health:

• Bonded (or non-friable) asbestos refers to materials containing asbestos that are solid and cannot be crumbled by hand or reduced to powder by hand. In this form, the asbestos fibers have been mixed with a bonding compound such as cement. This type of asbestos is commonly referred to as asbestos-containing material (ACM). Some ACM can contain very high (up to 70% asbestos fibers by volume).

• Unbonded (or friable) asbestos refers to materials containing asbestos that, when dry, are in powder form or may be crushed or pulverised into powder form by using your hand (Safe Work Australia, 2020)/crumbly asbestos (WHO, 2020). The fibers in these materials can readily become airborne and then settle as dust on surfaces.

Image 2: Example of Bonded and Unbonded Asbestos

Source: iStock.com.

Note: Bonded asbestos (non-friable), if in good condition and left undisturbed, generally represents a lower risk to human health as the fibers are less likely to be released and to become airborne. However, asbestos fibers within bonded ACM may become friable through weathering, damage, normal wear and tear, and/or through mechanical/construction activities (such as drilling or sawing). Friable asbestos can become airborne when disturbed and represents a greater risk to workers and surrounding communities due to the increased risk of inhalation of asbestos fibers.

Some examples of potentially asbestos-containing materials include:

• Flat and corrugated sheeting (commonly known as fibro cement sheeting)

• Cement pipes

• Insulation (buildings, electrical wiring, etc.)

• Floor tiles

• Adhesives

• Roofing

• Textiles

• Textured paints

• Automotive parts such as brake pads

For a comprehensive series of images showing ACM features that correspond to the common ACM uses, please refer to Figure 3 in Section 6.

2.5 What Are the Risks of Asbestos Exposure?

The World Health Organization (WHO, 2006) recognises that all types of asbestos cause disease and that evidence for increased cancer risks have been observed in populations exposed to very low levels of asbestos. Similarly, the International Agency for Research on Cancer (IARC, 2018) considers that all forms of asbestos (i.e., chrysotile, amosite, crocidolite, anthophyllite, tremolite and actinolite) are carcinogenic to humans, meaning that exposure to all forms of asbestos can cause cancer, including mesothelioma (cancer of the lining of the lung), and cancers of the lung, larynx, and ovary.

Asbestos-related diseases (AR...