Posted By Karina Brady Is it true that the fibres found in chrysotile or white asbestos are quickly eliminated by the body and therefore don't pose a serious threat of lung cancer or asbestosis. I recently read this on a Canadian company's website. This company produces building materials containing chrysotile.

Posted By Arran Linton - Smith Out of interest, which web-site is this? Quoting from the HSE publication HSG189/1 on page 4 "All are dangerous, but crocidolite and amosite asbestos are known to be more hazardous than chrysotile".

Posted By Rob T Karina, In answer to your first question - the answer is no HOWEVER, chrysotile is not anything like as dangerous as it can be made out to be. The reason that chrysotile is not as dangerous as crocidolite and amosite is down the the shape of the fibres. Where croc and amo are dagger shaped and can pierce the lungs etc reasonably easily, the chryso are snake-like or wavy which makes it very difficult to penetrate. None of these however can be broken down by body defences. Chrysotile has never been associated with mesothelioma but was the main cause (or together with the other types in a mix) of asbestosis. This is a wholly different problem as this is associated with clogging up of the lungs not causing cancer type growths. The main people to get asbestosis were laggers, plumbers etc who worked with large amounts of chrysotile asbestos over a period of years. So (and that was the most potted version I've ever written on the subject) the answer to your question is, no it is not safe but don't worry about the occasional exposure. With regards Rob

Posted By Dave Wilson This www is a website sponsored by the Canadian Chrysotile Industry and is very very one sided so to give a balanced view go to http://www.ibas.btinternet.co.uk/ for a totally differnt perspective (International Ban Asbestos Secretariat).

Posted By Mike Draper There is some under publicised Norwegian research, in the form of an epdemiological study. The research could be interpreted to mean that there is little to be gained by considering the different forms of asbestos to present different degrees of risk and that chrysotile is little different in its long term effects than amphiboles.

Posted By Adrian Watson Dear All, A number of interesting points are made, some of which need clarification. Whilst Chrysotile is curly, it easily gets past the hairs in your nose and past the muco-cilliary escalator in the trachea and bronchus to the respiratory regions of the lung. Once inside the airways, its physical characteristics mean that fewer numbers of fibres are deposited in the lower regions of the lungs than an equivalent concentration of amphiboles. Once in the respiratory lumen, Chrysotile has a much shorter half life than Amphiboles. This means that the fibres do not remain inside the lung as long as amphibole fibres. Furthermore, Chrysotile fibres are less toxic than amphiboles fibres. These facts mean that fibre-for-fibre starting with an equivalent concentration of chrysotile and amphibole in air produces a less harmful dose of Chrysotile within the lungs. At present there is still a great uncertainty as to whether chrysotile can cause mesothelioma in the absence of the presence of Tremolite. Furthermore, whilst there is no doubt as to whether asbestos causes lung cancer, there is still a question about what levels of exposure are needed to cause lung cancer; the general consensus is that exposures to asbestos need to be around the region of those that cause asbestosis. If you want to read further I suggest you read Asbestos Risk Assessment, epidemiology and Health effects (CRC 2005) ISBN 0-8493-2829-2 or the Epidemiology of Work Related Diseases (BMA 2000) ISBN 0-7279-1432-4 Regards Adrian Watson LLM MSc Dip Occ Hyg FIOSH FFOH MCIEH Registered Occupational Hygienist

Posted By Adrian Watson Dear All, A number of interesting points are made, some of which need clarification. Whilst Chrysotile is curly, it easily gets past the hairs in your nose and past the muco-cilliary escalator in the trachea and bronchus to the respiratory regions of the lung. Once inside the airways fewer numbers of fibres are deposited in the lower regions of the lungs, for an equivalent concentration of amphiboles in air, because of Chysotiles physical characteristics (fibres tend to be longer and curly). Once in the respiratory lumen, Chrysotile fibres have a much shorter half life than Amphiboles. This means that Chrysotile fibres do not remain inside the lung as long as amphibole fibres. In addition Chrysotile fibres are less toxic than amphiboles fibres. These facts mean that fibre-for-fibre, an equivalent concentration of chrysotile and amphibole in air produces a less harmful dose of Chrysotile within the lungs. At present there is still a great uncertainty as to whether chrysotile can cause mesothelioma in the absence of the presence of Tremolite. additionally, whilst there is no doubt as to whether asbestos causes lung cancer, there is still a question about what levels of exposure are needed to cause lung cancer; the general consensus is that exposures to asbestos need to be around the region of those that cause asbestosis. If you want to read further I suggest you read Asbestos Risk Assessment, epidemiology and Health effects (CRC 2005) ISBN 0-8493-2829-2 or the Epidemiology of Work Related Diseases (BMA 2000) ISBN 0-7279-1432-4 Regards Adrian Watson LLM MSc Dip Occ Hyg FIOSH FFOH MCIEH Registered Occupational Hygienist

Posted By Adrian Watson Yes, If used safely. Regards Adrian

Posted By Dave Wilson Bit of a cop out mate, as anything if used safely is safe!

Posted By Frank Hallett Thanks Mark - what I said at the beginning! Frank Hallett

Posted By Frank Hallett I am neither agreeing nor disagreeing with your last post Dave; you have a point, but it's just not the same arguement as started this thread. The Control Limits exist, therefore it is not safe! Perhaps the apparent inconsitancy of the proposed approach to exposure to ACM's could be another excellent discussion? I think that you should kick it off as a new one Dave. Frank Hallett

Posted By Frank Hallett Dave, I consider that your clearly stated vested interest v personal opinion makes it quite clear that you're the best form of impartial respondant. Go for it. Frank Hallett

Posted By Adrian Watson Dave, My answer was not a cop out. The question is "What has no risk?" Frank, The fact that Asbestos has a control limit does not make it an unacceptable risk, there are many items that do not have a control limit or WEL that pose a far greater risk to those exposed to them. Regards Adrian.

Posted By Bill Fisher The question asked is "Is Chysotile Safe?" And the bottom line is that it is not safe! I am pleased to see the fact that some respondents recognised the politics of the Canadian view. And remember that is only one country's view. To put this question into perspective when you stand Chrysotile alongside Amosite and Crocidolite, then it is considered less harmful - as others have said. But would you be happy to breathe in Chrysotile fibres in any quantity? The fact that a small dose may not go on to create asbestos illnesses does not make it safe. Its' properties may make controls easier, less onerous but anyone willing to breathe the fibres, in my mind, is asking for trouble. Bill P.s. not a dissimilar discussion than that of passive smoking, me thinks!

Posted By Bill Fisher Adrian Your point is not lost, I can see the similarity to radionuclide uptake in daily life and as you say there are levels of exposure with tolerable levels of risk. The key to the tolerability of the risk is the dose of the substance. But again in answer to the question in the present climate is that it is not safe. If the person asking the question understood the subject then I suspect we would have had a different question. Once again the bottom line is that everything can be safe - but that is dependant on administered controls therefore dose - but the reality is everything can cause harm; just some more easily than others. Bill

Posted By MungoDundas Think about exposure to asbestos, could I ask - are some of these fibres so small that there are not visible? Eg small pile of undisturbed asbestos (unknown type) lying on a cupboard shelf. Would the mere fact of opening the cupboard door to enter, causing a minor air swirl, dislodge lighter invisible fibres into the air, whilst the main pile remains appearing undisturbed?

Posted By Dave Wilson Individual fibres cannot be seen by the naked eye, so there could be millions in the air, Remember the clearance level is 0.01 f/ml and control limits etc 0.2 f/ml for amphiboles. Someone do the maths and covert that into say a room of 50 cubic meters!!!!!!

Posted By Alison WR It is less dangerous than croc or amo, but that does not make it safe. Canada exports about a third of a million tons of chrysotile a year, so is keen to argue that 'white is safe'. There are Canadian towns that have declared their asbestos spoil heaps to be heritage sites. So far as I recall, a few years ago, Canada threatened the EU with a full-scale trade war because the EU banned the import of any asbestos on the grounds of safety. The dispute went to the World Trade Organisation, and Canada lost.