Very Simplistic Equation Circulated: No Asbestos = No Danger

It was thought that it would be enough to replace chrysotile fibres with other fibres.  To polish their image and avoid responsibility for their past activities, some manufacturers decided to cease using chrysotile in as many products as possible, while using substitutes that had not always been scientifically tested either for technical or medical problems.

Replacing chrysotile is a very complex operation.  The risks and dangers with many other fibres are sufficiently clear now that some legislators are starting to impose regulatory constraints on these substitutes.  The regulatory authorities are invited to apply the standards for chrysotile to all industrial fibres if they truly want to protect the health and safety of workers.

Since the main argument used to substitute chrysotile is based on the premise that its use presents a potential health risk, it is essential to ensure that the replacement products are harmless or less harmful, as indicated in Convention 162 from the ILO.

Since 1993, a group of experts convened by the WHO, stated in Environmental Health Criteria 151, that all respirable and biopersistent fibres must be tested for their toxicity and carcinogenicity.  In fact, recent studies show that many of the fibres used to replace asbestos in many products are not without potential risk.  These are primarily glass fibre, rock wool, refractory ceramic fibres, aramid fibres and cellulose fibres.  The same year, the International Program on Chemical Safety (IPCS) clearly recommended that “exposure to any breathable and durable fibre should be controlled in the same way as asbestos until such time as it is proven that less stringent controls would be sufficient."

We understand that Germany classifies glass wool, rock wool and slag wool substrates as carcinogenic products.  Several other countries have also taken the same approach and have adopted standards for exposure and work methods for several fibres.  However, the fact remains that to effectively protect the health of workers regulations should apply to all fibres. The European Commission further announced, in 1994, a complete study program on fibres that should make it possible to establish a new classification according to their carcinogenicity.

The scientific community agrees that in too many cases, there is no valid scientific evidence that supports the assumption that substitutes are safe.  Even the “Institut National de la Santé et de la Recherche Médicale (INSERM)” in France, recognizes that the scientific data is insufficient on substitute products to make a decision regarding their harmfulness. More recently, the WHO reached the same conclusion in its publication “WHO Workshop on Mechanisms of Fibre Carcinogenesis and Assessment of Chrysotile Asbestos Substitutes.”

When the Court of Appeals of the United States reversed, in 1991, the asbestos ban and phase-out rule proposed by the EPA, it did stress that national legislators should consider the cost of introducing measures to ban a product. It also stressed that substitute products for products that contain asbestos also present potential risks to human health that could be more serious than potential risks from asbestos.

This is also a rising concern among workers and regulatory agencies. The ILO adopted a Code of Practice for the use of Synthetic Fibres, which recommends the same precautionary measures as with chrysotile.  This comes as no surprise as manipulating, mixing, cutting and unprecautionary handling of all fibrous materials can generate dust.  In the case of chrysotile, international references are available for determining, what is a reasonable limit of dust exposure not to exceed. This is unfortunately not always the case for most substitute fibres. 

The prohibition of asbestos would mean substituting a known and adequately regulated product with others that are unknown and often not regulated.  Several of these products have similar effects on health without the benefits of chrysotile.  For example, recent studies show that certain types of fibres and products used to replace chrysotile are more biopersistent than chrysotile.

Because the use of substitute fibres to asbestos is relatively recent, not enough epidemiology studies are presently available that evaluates their human health effects.  With the negative publicity arising from the past uses of asbestos fibres, these new fibres were developed to take over a growing market, encouraged by political stance (like in the European Union) supporting their use.  Many scientists have raised serious concerns about possible health effects of these new materials and especially about the fact that the reliable scientific information is very meagre or non-existent. Today, it has become abundantly clear that “biopersistence” is one key parameter to take into account when comparing the toxicity of respirable fibres.

It has been confirmed by numerous scientists, in several studies, that respirable fibres have different biopersistence characteristics, which may vary according to their respective manufacturing process and chemical composition.  Current international efforts in developing standardized methodology for durability and biopersistence assessment of all industrial fibres are certainly opportune, as this parameter now appears to be an important element for carcinogenic risk evaluation and eventually occupational standards setting policy.  Indeed, the 2001 IARC Monographs Programme to re-evaluate carcinogenic risks from airborne man-made vitreous fibres reinforces the concept that “high biopersistence of inhaled fibrous materials is correlated with high carcinogenicity”.  The Monographs Working Group concluded that only the more biopersistent materials remain classified by IARC as possible human carcinogens.  As a matter of fact, the labelling regulation in the European Union states that respirable particles with very short biopersistence can be exempted from the “carcinogen” label. 

Results of the ongoing study by three laboratories in Switzerland, Germany and in the U.S.A. demonstrates that the half-time clearance for Canadian commercial chrysotile, i.e. the number of days necessary to eliminate half of the fibres remaining in the lungs after end of exposure, is about 15 days.  This number is in accordance with other data published recently about chrysotile, and in line with epidemiology studies confirming that amphiboles are more fibrogenic and carcinogenic than chrysotile (amosite asbestos has a half-time clearance of ~ 466 days).

How does chrysotile compare with the most commonly used replacement fibres?  Less durable, according to recent studies using the same methodology.  For instance, ceramic fibre (RCF 1) has a half-time clearance of 60 days, aramid fibre around 90 days and cellulose fibre over 1000 days.

Fibre-Cement Without Chrysotile

On a worldwide scale, 95 % of the chrysotile used is for the manufacturing of asbestos cement products.  This includes corrugated sheets, flat sheets, slates, pipes, etc..  Over the last decades, many materials were developed to compete with asbestos cement products (a/c), but they are not usually in the form of asbestos cement.  For example, alternative pipe products are made with polyvinyl chloride (PVC) or ductile iron.

The characteristics of these products vary widely making it impossible to establish clear comparisons.  However, it should be noted that no single fibre can replace chrysotile in all its diversified applications.  Furthermore, their use is somewhat more limited and involves substantial economic restrictions compared to chrysotile.  These would include price, health risk, durability, energy consumption and environmental considerations that are often higher than for chrysotile.

No fibre can easily replace chrysotile for the manufacturing of pipes.  Tests were carried out with various materials, but none were satisfactory.  Natural or synthetic fibres can therefore only replace chrysotile for the manufacture of flat or corrugated slates, however for the latter, the resistance provided by substitute fibres restricts manufacturing only the thickest sheets and with the highest level of corrugation.

Chrysotile and Portland cement have a binding property that cannot be matched by many materials.  Introducing fibrous cement technology without chrysotile is therefore not easy.  Dansk Eternit in Denmark and Supradur in the United States are faced with huge lawsuits due to the fast deterioration of their fibrous cement products that do not contain chrysotile.  Similar tests on cellulose based composite products in Central America led to disastrous results and these products were quickly withdrawn from the market.  Based on experiments carried out to date, it appears that fibre-cements that do not contain chrysotile are particularly sensitive to climatic conditions, particularly in hot and humid areas and areas with frequent freezing and thawing cycles.

Although experiments were carried out with a score of natural and synthetic fibres, only two, cellulose and the polyvinyl alcohol (PVA) resulted in any kind of commercial success.  While the use of these products indoors does not seem to pose problems, their external use must be limited to areas with suitable climatic conditions.

In addition to the resistance and durability aspects, chrysotile-cement is less expensive than its competitors because chrysotile fibre is cheaper.  Cellulose costs more than chrysotile.  PVA is also very expensive.

Asbestos: The Real Story...

For many people, the word "asbestos" inspires a negative reaction.  In some countries, especially in Western Europe, this is even an obsessive fear.  We all know now that the bad conditions to which workers were subjected in the past, in mines, manufacturing plants and in spraying pulverized products, are the responsible for incurable, sometimes fatal, industrial diseases. With improved scientific knowledge in toxicology and epidemiology, it is now recognized that diseases related to asbestos have a long latency period (from 20 to 40 years) and that chrysotile is much less problematic than amphiboles. It is not surprising to diagnose today diseases related to the past use of asbestos. They are the sad consequences of the past, but they have nothing to do with working conditions prevailing now, even though precautions must always be taken as it is the case for all products, substances or fibres presenting a potential health risk.

People are more influenced by alarmist views than by concrete facts.  It is easy to generate fear, to simplistically associate today's diseases with current conditions of use and to confirm without solid proof that substitute fibres are probably less harmful. This is false. In such a context, the solution also appears very simple -- ban rather than regulate.  But this is also trickery.

Reality is quite different.  Between 1950 and 1999, over 22 million tonnes of asbestos were used in the fifteen countries that formed the European Union for the construction of commercial buildings and distribution systems for drinking water and waste water.  Europe would have had a very difficult time reaching its current level of development without this considerable uses of asbestos products. Now that major infrastructure work has been completed in Europe, high-technology industries are producing expensive substitute fibres.  Finished products that contain these fibres are of equal or inferior quality than those containing chrysotile, but their prices are much higher and their lifespan is more limited. It is not surprising to see supporters of substitute products interested in feeding the current psychosis over asbestos in various countries where they wish to expand their market.

Make no mistake about it: The basis for the current debate is not only an occupational health and safety issue. We are witnessing a crusade with huge economic stakes.

Controlled Use: Myth or Reality?

International experts recognize that controlled-use exists and that when implemented, provides adequate protection to workers health and safety in the mining and manufacturing sectors.

Thus, by applying the specific and necessary measures, including education and training, recommended work methods and the use of appropriate tools and equipment the risk to the health of workers, will be undetectably low. The principle of controlled-use was not created by the chrysotile industry and does not apply to this industry alone.  This is a general principle of risk management recommended for all products or technologies that may present a risk to health, in the absence of appropriate controls and guidelines. 

Industrial development has brought us numerous potentially hazardous products which we use daily and which are possibly more risky than chrysotile and thus must be used in a responsible manner. For example, the use of certain natural resources like lead, mercury, cellulose, as well as most chemicals such as pesticides, must always be controlled in order to prevent possible negative health effects to humans and the general environment.

This brings us to an interesting paradox. Opponents to the safe and controlled-use of chrysotile assert, without hesitation, that this practice is a myth. They even qualify it as a "fantasy", since there are inconveniences that make its application “impossible”. How can an unskilled worker, when he is manipulating products that contain chrysotile and faced with these "inconveniences", alternatively, meticulously, use substitute products safely at a similar worksite, but cannot do so with products containing chrysotile?  This lack of logic makes us wonder.

The implementation of the controlled-use principle is the responsibility of both industry and the workers. Ignorance of this principle for chrysotile is not only refusing to believe the evidence, but also accepting the fact that as soon as a product presents a potential risk to the health and safety of the workers who handle it, it must be prohibited.  In this way, the door is wide open to the adoption of excessive protectionist regulations for unspecified public health issues, or due to the pressure of lobbying from competing alternative products manufacturers.  Recently, the European Union selected for prohibition or strict regulations nearly 1,500 natural substances and industrial products, including a possible progressive prohibition of PVC.

It is undeniable that industrial development has contributed to improving our societies, but it has also taught us to create and manage many products that are potentially dangerous. International standards were developed and implemented to ensure manufacturing and the use of numerous products while minimizing the risks. The search for “zero” risk that underlies all of the anti-chrysotile propaganda is unrealistic. All activities involve some risk.

Safe Use of Chrysotile

The very concept of safe use is from Convention 162 of the ILO.  This Convention recommends a strict framework for the use of chrysotile, but it does not include prohibitions other than for crocidolite and for loose, friable asbestos in fireproofing applications. This Convention remains the international legal instrument for the controlled-use of chrysotile asbestos approach.

We must stress, at this point, that Convention 162 provides for the substitution of chrysotile or materials that contain chrysotile by a substance that offers the same technical advantages but are harmless or less harmful. (ILO Code of Practice)

Countries are encouraged to ratify and implement ILO Convention 162 to ensure that chrysotile asbestos is used safely in their country. Countries that choose not to ratify this regulatory instrument officially should include the controlled-use approach in their national legislation for all activities involving exposure of workers and the general public to asbestos fibres.

The principles mentioned in the Convention cover all sectors where a risk of occupational exposure to asbestos exists. This includes extraction work and mineral processing, production, usage, application, removal, repair, maintenance or demolition of products that contain asbestos.

All high-density products containing chrysotile fibres (defined as products that cannot be dispersed, pulverized or reduced to powder under hand pressure when dry) should be allowed.  For example, chrysotile-cement pipes and sheets, friction products, sealing joints and asphalt roof coatings.

The ILO Convention also makes provisions for the following sectors:

·        Supply of appropriate work clothes that should not be worn outside the work place.

·        Promotion and distribution of information and training of all interested parties regarding the risks to health with exposure to asbestos, as well as prevention and control methods.

·        Use of a suitable label with pictograms and warnings that should be placed on bags containing asbestos fibres and on products containing asbestos to inform users that they should use appropriate equipment.

·        Elimination of waste containing asbestos in a manner that does not present a health risk to workers or residents in the vicinity of the factory.

·        Medical examinations to monitor worker health in relation to occupational hazards and to detect occupational diseases by exposure to asbestos.

·        Application of government or independent provisions and sanctions if necessary.

EXPLAIN THE NEGATIVE REPORTS ON ASBESTOS!!

• The bias against the use of asbestos in a few countries is due to the adverse Western media coverage relating to altogether different usages of asbestos in the past in those countries i.e. sprayed on asbestos and friable low-density asbestos insulation used under uncontrolled conditions at that time due to lack of adequate scientific knowledge. Though these particular usages have since been discontinued, the claims relating to the past keep appearing in the media resulting in general confusion. (there is no such usage in India)

• But, once the scientific research into the risks of asbestos was set in motion, development and installation of pollution control systems took place, enabling the asbestos mining and asbestos cement industries to maintain safe and acceptable levels of dust pollution at the work places.

• Once the permissible levels of exposure were defined, the Governments have stepped in and laid down pollution control regulations and the mechanisms to enforce their compliance. Compliance with these regulations and standards assure the workers in asbestos-cement industries a risk-free environment. For the consumer, the Asbestos Cement products were and are always safe as the fibres are locked in layers of cement–fly ash matrix.

Asbestos and Asbestos Cement Products

Asbestos is a naturally occurring mineral found in underground rock formations. For commercial purposes, it is recovered by mining and rock crushing. Fine fibres, invisible to the eye, are present in the air and water in every region of the globe. Hence, all of us may be inhaling and also ingesting them through drinking water every day. There are two different varieties of asbestos (i) Chrysotile variety and (ii) Amphibole variety. Amphibole variety comprises of Crocidolite, Amosite, Tremolite, etc. Only Chrysotile variety is in production and use for the past two decades.

Only Chrysotile variety (white asbestos) is in commercial use now. Indian asbestos cement sheet and pipe manufacturers import all their requirements of chrysotile fibres from Canada, Brazil, Russia, Zimbabwe and Kazakhstan for production of AC sheets and pipes. Chrysotile asbestos is also mined in India in very small and insignificant quantities which are of no consequence or relevance to our asbestos-cement production. The other varieties of asbestos known as amphiboles (crocidolite, amosite, tremolite, etc) which were considered rather unsafe, have been prohibited all over the world including in India. Wherever asbestos is produced or used in products, only Chrysotile variety is permitted now. 

Chrysotile asbestos fibre, (composed mainly of magnesium and silica), is a great reinforcing agent. While its tensile strength is greater than steel, it has other rare and highly valued fire-retardant, chemical-resistant and heat-insulating qualities. In fact it is a magic mineral.

Asbestos Cement Products

AC products are made with a mix of chrysotile fibres (about 8-9%), cement (about 40%), Fly Ash (about 30%), the rest being wood pulp and water. Over 90% of asbestos fibre imports of India go in to AC sheet and pipe production.

AC Sheets have been used in India for over 70 years. Being weather-proof and corrosion resistant, these sheets are practically ageless and maintenance free, whereas metal sheets corrode and deteriorate with age and exposure. (See chart for comparison).

AC Sheets have also proven to be the most cost effective, easy-to-install, strong and durable roofing material for warehouses, factories, low-cost housing, and practically any structure needing a roof. Apart from India, Russia, China, Thailand, Brazil are some of the largest users of AC Sheets.

AC sheets and pipes, being corrosion and erosion-free, once properly laid and jointed, need no maintenance or replacement. They are also very cost effective

AC products, which consume low energy in manufacture and do not in any way deplete the natural resources, meet the needs of the country in its developing economy in the context of rapidly rising population and limited resources.

AC products are manufactured under (ISI) licence strictly conforming to the standards of Bureau of Indian Standards. IS 459/1992 for Corrugated Roofing Sheets, IS 2098/1997 for Building Boards, IS 2096/ 1992 for Flat Sheets and IS 1626 (Part III)/ 1994 for Roofing Accessories. AC Pressure Pipes are covered by IS 1592/1989.

Source: http://acpma.com/fact-asbestos.html