Counterpoint:

Why white asbestos can be safe

The Fibre Cement Products Manufacturers Association (FCPMA) of Sri Lanka has sent the following response to an article published in the December 13 edition of the Sunday Observer titled ‘A view from the NBRO – Banning asbestos to save lives.’

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The Fibre Cement Products Manufacturers Association (FCPMA) is aware of the range of information available both for and against the usage of chrysotile or ‘white asbestos.’

This article highlighted many areas which refer overwhelmingly to the hazards of ‘white asbestos.’ Hazard, however – as we know from the case of the recent classification of red meat as carcinogenic by the WHO – is not the same thing as risk. In other words, it tells us that something can be harmful, but it does not explain the circumstances or dose levels. This is the same for chrysotile.

Why it is safe

Over many decades, scientists, scholars, researchers, global advocacy bodies and other interested parties have debated and come to conclusions on various materials – both natural and manmade – that can pose risks to human health.

One such material that has been debated on a global scale for many years is asbestos. Although a naturally occurring mineral that has been mined for over 4,000 years, large-scale mining began at the end of the 19th Century, when manufacturers and builders began using different forms of asbestos due to its desirable physical properties such as sound absorption, average tensile strength, resistance to fire, heat, electrical and chemical damage and affordability.

It is essential to note that there are fundamental bio-chemical differences in the family of naturally occurring materials – known commercially – as asbestos. Specifically, there are two distinct and different families of asbestos: Serpentine or ‘white’ Chrysotile asbestos and all the others, known as amphiboles or ‘blue and brown’ asbestos.

Today, the only form of asbestos in commercial use is Chrysotile as science teaches that not all asbestos types are harmful or hazardous to health as previously suggested.

Extensive usage of hazardous blue and brown asbestos under poor worker safety conditions in the 20th Century led to the understanding that asbestos dust inhalation over prolonged periods of time can cause serious health concerns. As a result, global bans are in effect for brown and blue asbestos – while Chrysotile is not banned in over 140 countries – including the US, Canada, Russia, India, China, Brazil and others.

While there is no debate over the amphibole form, countries such as Thailand have recently reviewed the question whether to ban Chrysotile or not, given their history of using it for more than 70 years. In 2015, after a through scientific review, Thailand decided that when used according to safe use procedures.

WHO standards

In 2007, the World Health Organization (WHO) adopted the stance of the World Health Assembly (WHA) on the management of asbestos.

According to the Resolution, the WHO will work with member states to create global campaigns for elimination of asbestos-related diseases; bearing in mind a ‘differentiated approach’ to regulating its various forms.

An ILO Conference in 2010 also saw a resolution tabled for the banning of all asbestos fibre types. Since the ILO Convention 162 on Safety in the use of asbestos, adopted in 1986 and ratified then by 36 countries, recommended controlled use of Chrysotile asbestos, it is proven that Chrysotile fibres are globally in use.

A number of significant decisions regarding Chrysotile were made during the Rotterdam Convention held in Geneva in 2015. Specifically, once it was re-affirmed that there is no need for Prior Informed Consent (PIC) from countries to transport Chrysotile.

What is also important to note in the argument supporting Chrysotile usage is that “hazard” does not necessarily mean “risk.”

The International Agency for Research on Cancer uses the word “hazardous substance” in describing Chrysotile but does not refer to “risk assessment” being required. Several studies published in the likes of the American Review of Respiratory Disease and the British Journal of Industrial Medicine and have also found no detectable risks among Chrysotile cement manufacturing plants in the US and UK.

In the local context, consumers have trusted fibre cement sheets that contain a small amount of Chrysotile for decades due to their long lasting, durable, easy to use, affordable and tropical weather resistant qualities. The products manufactured locally contain 92% cement and only 8% Chrysotile fibres.

The blue and brown variants are not used in Sri Lanka.

The alternative products do not carry the same capabilities as roofing sheets do and come at a much higher cost. There is also no documented proof of any individual inflicted with any disease that could have been caused by extensive exposure to Chrysotile fibres. Typically, in Sri Lanka, the exposure levels are less than 0.01 fibres per cubic centimetre. Under such exposure levels there is no measurable risk of diseases such as cancer, asbestosis and mesothelioma.

Although a generic ban on all asbestos-related products has now been called for and is under discussion, it is important to note that more extensive research in to safe manufacturing processes, usage and recycling practices, alleged health risks and the viability of alternative products should be carried out before arbitrary decisions are made.

Understanding risk

• Very frequently, amphibole asbestos (Amosite and Crocidolite) was mixed with Chrysotile in past manufacturing processes and usage – thus resulting in a mixed fibre experience

• In the past, there was little or no attempt to differentiate exposure to these two different minerals, causing critical impact in terms of health effects and perception

Why some fibres cause disease?

• Fibre dimensions (length and diameter)

• Fibre bio solubility (durability)

• Fibre dose

Chrysotile

• Chrysotile is a rolled sheet material like mica

• The sheet is about eight angstroms (0.8 nanometers) thick and due to molecular constraints, is rolled into cylindrical form

• The cylinders are Chrysotile fibrils which bunchtogether to form a Chrysotile fibre

• The Chrysotile fibre is acid soluble (von Kobell, 1834; Pundsack, 1955)

• In acid, the rolled sheet of the Chrysotile fibrebreaks apart into small pieces.

• In the lung – the cell which clears fibres and particles from the lung – the macrophage –creates an acid environment

Recent toxicological explanations

• Chrysotile asbestos has a relatively short bio persistence and does not result in pathological response even in asub chronic inhalation

• Following such exposures, Chrysotile asbestos produces neither a pathological response in the lung nor in the pleural cavity

• Chrysotile fibres clear rapidly from the lung and are not observed at the visceral pleural surface, neither in the pleura nor on the parietal pleural surface

• With Amphibole fibres in the lung, immediately following a five-day exposure, the amphibole fibres have been shown to produce extensive inflammation with pathological lesions

• Within 28 days after the five- day exposure, interstitial fibrosis was observed in the lung

• The amphibole fibres are poorly cleared from the lung with the longer fibres longer persisting through the lifetime of test rats

• Within two weeks after the five- day exposure, amphibole fibres were:

o observed penetrating through the visceral pleural surface and

o were associated with extensive inflammation and fibrotic development in the pleura

• These pathological changes parallel closely those in humans who develop mesothelioma

The science and future

• The WHO Report on Chrysotile asbestos substitutes has supported that there is very little scientific basis for the evaluation of the proposed substitutes for Chrysotile

• For many of the fibre types, the limited data availability suggests that they should be of considerably greater concern than Chrysotile

• The cohorts studies, epidemiological reviews and inhalation toxicology studies provide strong support that Chrysotile is significantly less hazardous than the amphibole forms of asbestos, such as crocidolite and amosite

• With proper control and use, Chrysotile asbestos in its modern day high density cement applications does not present an excess risk of either lung cancer or mesothelioma of any significance to public and/or worker health