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| Sunday, 30 March 2003 |
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Features |  |
| News Business Features Editorial
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The Asbestos debate : Chrysotile Asbestos is not fatal In Sri Lanka only chrysotile (white) asbestos fibre is primarily used for the manufacture of roofing sheets. Any fibre in its natural state can cause harm. Cotton jins used to cause brown lung amongst the labour force before steps were taken to keep dust levels at a safe level. That does not stop people from wearing cotton clothing. Similarly asbestos fibre can be an occupational health hazard, only when the dust becomes airborne and is respirable and when such dust is inhaled in excessive amounts usually over a prolonged period. Asbestos fibre is not a health hazard when proper dust control procedures are in operation and this too is only in the manufacturing process. Stray or short casual exposure to asbestos dust involves no measurable risk. Any particle or fibre whose dimensions are less than a threshold value can be taken in by the human lungs. The amazing thing is the human lung has its own defense mechanism to fight such invasions according to Dr. Kevin Browne of the United Kingdom. Specifically as far as chrysotile fibres are concerned he states "if they penetrate as far as the lungs, these are defended by a particular white cell called a macrophage, which acts as a scavenger and moves around in the lung spaces mopping up all the dust and germs it finds there. The macrophage makes digestive juices, just as we do in our stomachs, and these juices are very acid. (PH4)" He goes on further to state, "chrysotile will dissolve in acid, whereas the amphiboles and crocidolites are acid resistant." The writer claims that "White asbestos is more chemically reactive with the tissues and once it reacts with the tissues it loses its structural elements." Perhaps this is because as scientifically proven, chrysotile fibre is dissolved by the macrophage in the lungs, which would of course make it difficult to recognize since it no longer exists! Furthermore asbestos cement products contain very little asbestos fibre, constituting not more than 10 percent of the total raw material mix. As such the much publicized effects of asbestos fibres is not relevant to the experience of the manufacture of asbestos cement products using only white asbestos. The writer addresses many topics which are totally irrelevant in our local context. 1. The experience of mines in some other part of the world. However there are no mines nor have there ever been asbestos mines in Sri Lanka. 2. Information on Blue Asbestos It is a well known fact that blue asbestos was the main culprit behind many asbestos related diseases leading to its ban some time ago. It is not in use at all in Sri Lanka. 3. The ban on asbestos by several countries Although some countries have banned asbestos still 60 countries including USA, Japan, China, India, Russia, Thailand etc. use chrysotile fibre for the manufacture of many consumer-safe products. Furthermore in two landmark cases in USA and Brazil a move to ban asbestos was overturned. The writer claims that a fungus forming on roofing sheets in warm humid conditions releases oxalic acid which eats up the bond between asbestos fibre and the cement and releases asbestos dust to the surrounding air. First and foremost the roofing sheets manufactured here contain less than 10% asbestos as mentioned earlier which is in itself insignificant. Secondly raw asbestos fibre being silicate mineral, once coated with cement or "encapsulated" cannot be separated and it loses the ability to become airborne. Thirdly the matrix of asbestos fibre and cement is formed in lamination and compressed to form a high density asbestos cement sheet. The sheet due to fungus or any other chemical reaction cannot release fibre particles to the air as the fibre is interlocked with the cement. Fourthly, studies conducted in Austria, South Africa and Germany has dust levels of 0.0001 to 0.005 fibres/cc of air in the neighbourhood of chrysotile cement sheet roofs. These levels, as per the above publication are far from any suspicion of causing asbestos related disease. As far as health issues are concerned we would like to point out the following: i) Out of a cohort of the largest sample ever of 11,000 Chrysotile workers, there are exposure levels below which there is no measurable additional risk of lung cancer around 900f/ml@year. That is, 90f/ml a year over 10 years down to 11.25f/ml per year over 80 years or 5.6f/ml over 160 years; clearly more than a normal lifespan. In other words the exposure levels of these workers resulted in an insignificant risk. Current exposure levels are being improved to 1f/ml. ii) The American Lung Association have stated in their website lungusa.org: smoking is the number one cause of lung cancer 87% of lung cancer cases are caused by smoking. Radon is considered to be the second cause of lung cancer in the US 12% of all lung cancer deaths are linked to radon. Although the finding also mentions asbestos briefly amongst one percent, it very clearly identifies other main culprits as uranium, arsenic and certain petroleum products. Asbestos' inclusion is probably due to the manufacture of friable products in the distant past. iii). Dr.M.A.Y. Ariyarathne of The Cancer Hospital clearly states that not even a single case of lung disease caused by asbestos has been reported in Sri Lanka. The writer is finding fault with ISO certification given to manufacturers of asbestos products. Our response is as follows: A National Standard has in its scope a specification that is prescribed for each product to maintain uniformity and interchangeability. Such standards exist for several products as well as for Asbestos Cement Sheets not only in Sri Lanka but by International Standards Organizations(ISO), besides British, Canadian, Indian, Indonesian and other countries. Furthermore certification by SLS is limited to assurance of conformity to standard. As an example Asbestos Mines in Canada and Brazil are given certification of ISO-14001 for Environmental Management. Several Asbestos Cement Manufacturers also have been awarded ISO-9000 and ISO-14000 in Sri Lanka as well as in other countries by reputed inspection agencies. This is also further assurance for the consumer that such certified manufacturers are following internationally formulated procedures in production to ensure a high quality end product. By boldly displaying evidence of certification manufacturers such as members of our association are displaying their pride in being a maker of high and set standards. The writer has made several suggestions which we would like to address in relation to their relevance ; I. He is asking responsible authorities such as ministries etc. to find the reasons that led many countries to ban asbestos. The Industry is already aware that the use of blue fibre to manufacture friable products led to its total ban in many countries since it was proved that exposure to it was harmful. It is high time he stopped beating a dead horse and misleading the public. II. He is suggesting that steps should be taken to phase out asbestos in Sri Lanka. Again the phase out and ban on asbestos in some countries was entirely caused by the use of blue fibre. It is therefore irrelevant in Sri Lanka's context where only white fibre is used. III. He is suggesting alternative organic fibres such as pine fibre. Firstly such fibre should be evaluated in terms of suitability and more important availability. Secondly would it be economically viable? Thirdly such fibre would be extremely susceptible to our local warm and humid conditions and sheets made utilizing pine fibre as a raw material would no doubt rot and deteriorate within a very short life span. IV. He is suggesting awareness programmes. The industry is already conducting many awareness and training programs both to its own employees as well as carpenters and masons for many years. In the interest of workers safety the entire production process is a closed loop wet process with absolutely no direct contact with loose fibre, which the writer himself agrees on. V. The writer is flouting the ready availability of services of professionals through the sponsorship of the Asbestos Disease Society in Australia. This society has clearly stated in their web site that they have established for the benefit of residents of New South Wale Australia only. Is he perhaps misleading the public? VI. & VII. He is suggesting to enlighten those living in houses with asbestos roofs on the dangers they face and is recommending an "encapsulation" treatment. The production process itself is an encapsulation whereby the chrysotile asbestos fibre is locked in by cement, there is no necessity for any further treatment to the sheet. The product is completely safe in the hands of the consumer and on the roof. |
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