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Asbestos Safety

Published: 03rd Jun 2013 in OSA Magazine

With inhalation as the main entry route for asbestos into the body, Gary Cheung addresses the importance of respiratory protective equipment.


The word asbestos is from Greek origin and has the meaning of inextinguishable or indestructible. Asbestos can be found within a set of six naturally occurring silicate minerals: chrysotile, amosite, crocidolite, tremolite, anthophllite and actinolite. Asbestos was discovered 4,000 years ago and has been widely used for its strength and unique physical properties. 

In the early 1900s, however, researchers began to identify a large number of early deaths and a prominence of lung disease in asbestos mining towns. By the 1940s, studies had shown that a rare form of cancer called mesothelioma was caused by exposure to asbestos. As more medical discoveries were made linking asbestos exposure to lung disease, governments in North America and Europe started implementing safety programmes to protect and minimise occupational exposure to asbestos.

Since the 1970s, Canada and America have continuously developed and enforced stringent laws and regulations around the use and manufacture of asbestos. Within the last ten years, countries such as Australia, France and New Zealand have implemented the total ban of importing, exporting and using asbestos. We have yet to see countries such as India and China adopt these practises.

Exposure and entry routes

The main route of entry for asbestos is through inhalation. When inhaled, our respiratory system cannot properly filter or clear out these fibres because of their microscopic nature. More importantly, these fibres begin to penetrate the lining of the lungs, resulting in various types of lung diseases such as mesothelioma, lung cancer and asbestosis, which is the scarring of the lung.

Unlike other diseases, symptoms and signs of asbestos related diseases are often latent and by the time of discovery, the disease may have manifested itself to the point of incurability. Studies have also shown a higher risk of lung cancer among smokers who are exposed to asbestos compared to non-smokers.

When working with asbestos, one must be aware of two main issues with regards to minimising exposure, the first of which is directly related to the worker. Those who are working with and/or disturbing asbestos containing material (ACM) when performing jobs such as cutting, repairing and cleaning are considered to be high risk personnel. They must be prudent in wearing the prescribed protective equipment, such as appropriate respirators and filters, as the disturbance of these materials often generates dust that can be contaminated with asbestos. The second issue is to implement work procedures that minimise or eliminate airborne asbestos dust generation to unaffected public spaces.

Asbestos fibres cannot be seen with the naked eye. Because there are no immediate symptoms of exposure, if an unprotected individual is exposed to asbestos at work it is very likely that he/she will bring asbestos fibres into the home.

As asbestos fibres can easily attach to an individual’s clothing, when the individual returns home and disturbs the asbestos, for example, by removing or washing the clothing, it can reintroduce airborne asbestos into the home, exposing family members and contaminating the premises.

Friable versus non-friable

Before implementing controls and utilising personal protective equipment (PPE), it is important to understand whether the ACM is friable or non-friable.

ACMs are defined by the American Environmental Protection Agency (EPA) as any material containing more than one percent asbestos, as determined using Polarised Light Microscopy (PLM). The distinction between friable and non-friable is made when the material is dry. Friable asbestos when dry can be crumbled, pulverised, or reduced to powder by hand pressure, whereas non-friable cannot. As such, friable materials are considered to be high risk as they can easily become airborne, making exposure difficult to control.

The condition and the type of material will often define the level of hazard. Some materials or products are in a friable state, such as mechanical and thermal insulation or fire stopping. These can be easily identified as friable due to the nature of the building materials. In materials such as drywall joint compound, however, where the asbestos fibres are embedded in the matrix of the compound for increased strength and durability, the nature of the asbestos is considered to be non-friable as it is bound into the compound. When the compound dries after application and over an extended period of time either dries or deteriorates, this material can be easily crumbled by hand pressure. Following the EPA’s definition, the material is considered to be friable and the application of PPE and the safe work procedures change as a result.

Establishing RPE

As asbestos fibres enter the body, internal organs such as the lungs and throat are vulnerable to the carcinogenic effect of asbestos fibres. Understanding the types of asbestos and main route of entry, it can be concluded that the primary protection required is a respirator equipped with a filter that filters at least 99.97% of airborne particles.

As the minimum, when working with asbestos or abating ACMs, disposable coveralls, gloves and booties need to be worn in order to protect the health and safety of not only the workers but also the public. The use of this protective equipment helps prevent the migration of the original contamination into non-contaminated areas.

In North America, there are different levels of respiratory and PPE requirements. The levels are often designed based on the severity, frequency, proximity and duration of the exposure. These levels are categorised and the level of required protection is determined for the workers.

In countries where specific categorisations of hazards have not been established, comprehensive studies including air monitoring and fibre counting analysis are then required to determine the level of work activities, the type of work and which type of asbestos fibres are present within the work environment.

Often, countries may also adopt other established organisations’ regulatory standards such as standards from the EPA or American Conference of Governmental Industrial Hygienists (ACGIH), as the nature and the type of asbestos work or environments being engaged in may be similar or even identical. If that is the case, independent research for workers’ exposure programmes may not be necessary.

The National Institute of Occupational Safety and Health (NIOSH) is a part of the Centers for Disease Control and Prevention (CDC), which is responsible for conducting research and making recommendations including the use of PPE for the prevention of work related illnesses.

In North America, many organisations adopted the scientific findings of NIOSH, following minimum standards for the following:
• Airborne fibre sampling
• Human exposure concentrations
• Prevention criteria in various work environments
• Abatement requirements
• Respiratory protection requirements

A detailed asbestos respiratory protection programme must meet the minimum requirements of protecting the health and safety of the specific group, whether that is workers or the general public.

Respirator fit

As mentioned in the opening, asbestos is a naturally occurring fibre and is hazardous when inhaled. NIOSH outlines the criteria for hazardous asbestos exposures by fibre length. If the fibres are greater than five micrometres in length, the recommended concentration of less than 0.1 fibre per cubic centimetre in an eight hour work shift is permitted within the workplace, as determined by a 400 litre air sample collected over 100 minutes, in accordance with NIOSH Analytical Method number 7400. Meanwhile, no worker should be exposed to more than one fibre per cubic centimetre at any given time; that is, concentrations should be no greater than 0.1 fibre per cubic centimetre within any given eight hour working day.

An effective respiratory programme, therefore, often works in conjunction with an updated and comprehensive asbestos management programme to provide maximum protection for the workers. Strictly using only a respirator is not enough and is considered to be poor health and safety practise.

In the event that respiratory protection is required for activities such as abatement, repairs and/or the disturbance of asbestos containing building materials, it is important to follow specific regulatory asbestos abatement guidelines.

Asbestos guidelines include, and are not limited to:
• Isolation of ACMs
• Limiting cross contamination
• Dust suppression
• Worker protection

As a result, many organisations elect to retain an asbestos abatement or hazardous material management contractor to assist in the removal of the material, thus providing their own respiratory protection programme. Larger organisations such as universities, public utilities or healthcare facilities may have the capacity to conduct minor repairs and clean up activities without retaining third party contractors. In those cases, a respiratory protection programme such as respirator fit testing is often in place for their respective employees, in conjunction with an existing asbestos management programme.

When using respiratory protective equipment (RPE) it is essential to know that the worker or the individual is wearing a fitted respirator. Respirator or mask fit testing determines whether the person is wearing the correct respirator for the shape of his/her face. Respirators come in various sizes and although they are adjustable, the shape and the size may differ between brands and models. Prior to using a respirator a qualified health and safety professional will conduct respirator fit tests using one of two methods: quantitative or qualitative. These are two very different fit testing techniques but the end results are the same as they both ensure that the respirator is working to prevent contaminates from entering through the respirator and being inhaled by the individual.

Quantitative testing

In quantitative fit tests a specific protocol is required. Rather than relying on the sensitivity of the individual being tested, an instrument is used to determine the quantitative level of air leakage around the face seal of a given respirator. This type of testing is most accurate as this method is not subject to the user’s sensitivity or bias. It is also the most scientific method with regard to testing the face seal of the respirator. This is often the preferred method but it is more time consuming and costly than qualitative fit testing. It also requires a power source to operate the instrument, meaning that portability might not be as convenient.

Qualitative testing

Qualitative fit testing, on the other hand, relies on the sensitivity of the individual being tested and not on instrument readings.

Test agents adopt the most commonly practised and accepted testing protocols, including:
• Saccharin - a sweet tasting aerosol
• Isoamyl acetate - a liquid that produces a sweet smelling vapour similar to the smell of bananas
• Denatonium benzoate - a bitter tasting aerosol

In the past, irritant smoke was used as part of qualitative respiratory fit testing but its use is not without concerns. Irritant smoke is made of stannic oxychloride, which produces hydrochloric acid when in contact with water vapour. Exposure to hydrochloric acid during a fit testing session produces an involuntary cough reflex. Due to the potential associated health risks, its use is not recommended by NIOSH.

Qualitative fit testing is considered to be the simpler testing method. The test determines whether or not the individual, with RPE donned, can detect the scent and/or taste of the aerosolised testing agent.

The results are solely based on the individual’s reaction to these agents, thus raising possible bias or insensitivity issues.

Another argument with this method is that some individuals may be desensitised to a particular agent over the course of their lives, which may produce a false positive result. In many cases, a sensitivity test is often conducted prior to donning the respirator; however, this is also dependent on and biased towards the individual’s ability to taste or smell the specific sensitivity agents.

Another factor which needs consideration when conducting qualitative respiratory fit testing is that some individuals may not cooperate with the testing, such as individuals wanting to get the process over and done with, resulting in another false positive during respiratory fit testing.

The positive side of using qualitative respiratory fit testing is that the testing equipment is extremely portable and does not rely upon any power source.

For this reason it is often used for on site respiratory fit testing, allowing workers to be quickly fit tested and resume work without much delay.

Regardless of the fit testing technique being used, it is essential to know that all respirator fit testing needs to be renewed after two years, and/or after the gain or loss of 15 to 20 pounds in weight - whichever comes first. The reason behind this is to ensure that there are no significant changes in the size of the individual’s face. In the case of pregnant women, they need to be refitted during and after pregnancy.

Today most asbestos abatement companies choose to use quantitative respiratory fit testing for its scientific accuracy and non biased findings. Results are scientifically documented, thereby relieving owners and supervisors from future liability.

Respirator types

The most commonly used respirator for asbestos abatement is the full face respirator, equipped with a P-100 filter cartridge. One of the main advantages of a full face respirator is that it not only provides respiratory protection at the highest level without using a power source or supplied air, but it also provides immediate eye protection. During abatement activities dust and debris are generated, meaning that very often safety glasses are required within these construction environments. Using a full face respirator, the face shield not only prevents any asbestos fibres from entering the lungs but it also acts as eye protection.

Full face respirators may, however, cause the individual to perspire more, especially within a hot working environment. The respirator may fog up or have a build up of condensation on the surface of the face shield, thus making it difficult to see after extensive use. In many cases, individuals can also use full face respirators equipped with a powered air purifier (PAPR).

PAPRs use a motorised air source to filter and clean ambient air before it is delivered to the user. This allows the wearer to have clean, fresh air by removing condensation from within the respirator. PAPR systems can use many different filters, such as a P-100 air filter.

In North America, PAPR is often used during high risk abatement situations. This includes but is not limited to the use of electrical tools on friable materials, such as using electrical saws for cutting asbestos containing acoustic ceiling tiles, as well as situations with a high concentration of airborne asbestos, approximately 100 fibres per cubic metre.

Some extreme and high risk situations may require a supplied air breathing apparatus (SABA) or self contained breathing apparatus (SCBA). In environments or conditions where clean air is not available, SABA or SCBA attached to a full face respirator may be required. In situations such as confined spaces or where air quality might not be suitable, supplied oxygen may be required.

For typical low to moderate risk activities, such as the removal of non-friable materials, clean up activities or the removal of friable materials without the use of power tools, a half face respirator will often suffice.

It is also very important to educate workers with regards to the use and maintenance of the respirator. Inside the respirator should be cleaned with disinfectant wipes before and after usage to ensure good hygiene practises. Inspect all parts of the respirator, ensure that the straps are in good condition to allow a secure fit and finally make sure filter cartridges are replaced periodically.

When working with asbestos there are no quick and fast rules about respiratory protection, as other atmospheric hazards may be present. As a part of the respiratory protection programme, pre-start assessment and background monitoring are therefore highly recommended to ensure the correct work procedures are being followed and the appropriate PPE is used.


When working with asbestos safety should not be taken lightly. PPE is the only line of defence that protects workers and separates them from hazards. Safe work procedures should be followed, with hazards isolated wherever possible.

Engineering controls such as negative pressure should be utilised inside containment areas to reduce the number of airborne fibres during abatement activities.

Even with all these measures in place, it is imperative that workers are educated in respiratory and personal protection.

Asbestos is invisible, it is airborne, and it kills. Protect yourselves, your colleagues and your families by following best practise and working safely.  


1. What is asbestos. American Cancer Society, Retrieved – December 18, 2012.
2. SC refuses to ban asbestos in the country. The Hindu, Retrieved – December 18, 2012.
3. Berry, G.; Newhouse, Muriell.; Turok, Mary (1972). “Combined Effect Of Asbestos Exposure And Smoking On Mortality From Lung Cancer In Factory Workers”. The Lancet 300 (7775): 476.
4. NIOSH Pocket Guide to Chemical Hazard – Asbestos, Appendix C – National Institute of Occupational Safety and Health, Education and Information Division.

Published: 03rd Jun 2013 in OSA Magazine


Gary K Cheung

BreatheSafe Consulting is a comprehensive environmental health and safety consulting company which has provided consulting services for healthcare organisations and private home owners since 2009. GK Cheung specialises in indoor air quality, hazardous building materials management, mould and moisture assessments, and health and safety legislative requirements. In addition to environmental health and safety assessments and evaluation of the workplace and home, the company also has a strong focus and interest in developing and implementing health and safety programmes in the healthcare facility sector.

In this capacity, Cheung has gained valuable and intensive health and safety experience working for consulting firms such as Golder Associates Ltd, AMEC Earth and Environmental, T-Harris Environmental Management, and Giffin Koerth Forensic Science and Engineering. As a result of this experience, Cheung has gained knowledge and expertise which spans across the disciplines of environmental, occupational hygiene, occupational health and safety management, and building science assessments.

Owner and principle of the company, Cheung has an Honours of Science degree in Organic Chemistry from the University of Toronto, and an Honours of Applied Science degree in Occupational Health and Safety from Ryerson University. He also completed a Masters in Science degree in Building Science through Ryerson University. Cheung is a strong believer in continuing education, and is finishing a Business Development and Management certification through Seneca College.

Gary K Cheung



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