health and safety

Uncontrolled work conditions, work with friable insulation materials and the extensive use of amphibole asbestos fibres in the past have resulted in asbestos-related disease. But times have changed: the types of fibres and products used are different, and dust control technology has evolved. Today, amphiboles are no longer used, the use of low-density friable insulation materials has been banned, and exposure limits for chrysotile are hundreds of times lower than past worker exposures.

All asbestos-related diseases have a long latency period, that is, it takes 20 to 40 years for the first symptoms to appear. Given the poor work conditions of the past, the widespread use of amphiboles up until the 70's, and this long latency period, it is not surprising that new cases of asbestos-related disease continue to be observed. But this has nothing to do with today's products containing only chrysotile and work conditions.

Even if these friable products containing chrysotile are present in many commercial buildings, mostly in Europe and North America, removal of asbestos insulation should be considered a measure of last resort and undertaken only when the material is beyond repair or at the time of major renovation work or building demolition. Hasty elimination of asbestos insulation considerably increases the probability that controls will not be adequately enforced, thus presenting a source of risk not only for the workers, but for building occupants as well.

Protecting worker health: Control begins at the source

As part of its ongoing commitment to protecting worker health, the world's major chrysotile producers and exporters have developed a responsible-use initiative, the objective of which is to supply fibre only to those product manufacturers who comply, or have committed to comply, with national safety regulations.

In the vast majority of countries, chrysotile fibre is processed in highly automated plants that apply very strict monitoring and prevention measures. These measures include sound work practices and house keeping measures, appropriate dust control and ventilation systems and worker education and training. Regular surveys of Asbestos International Association members in 35 countries, have found that 87% of workers are exposed to below 0.5 f/ml on average, and that only 1.3% have a rate of exposure above 2 f/ml.

Construction site handling

The application of recommended installation techniques can totally prevent cutting chrysotile-cement on construction sites, the primary source of exposure for workers. Where cutting or drilling is required, hand tools or low-speed tools, in combination with wetting will ensure that dust is kept to a minimum. The following table provides a summary of exposure levels typically found for a range of operations using hand tools or low speed power tools during the installation of asbestos-cement products.

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* Short-term average exposures during cutting operations. 8 hour time-weighted average would be much lower.

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Evolution of dust levels in Québec mines 

As the following graph demonstrates, over the last 20 years, the average dust level in Québec's chrysotile mines has declined from 16 f/ml to 0.4 f/ml, a level at which no excess risk to worker health can be detected.

Problem areas

While it is clear from the statistics presented above that in the vast majority of cases chrysotile asbestos can and is being used safely throughout the product lifecycle, some problem areas that need to be addressed still remain. In some countries, not all companies have put in place appropriate preventive and control measures. This is especially true of some small- and medium-size businesses.

Toward responsible use

To address this problem, the chrysotile producers of Zimbabwe, Québec, Brazil and Swaziland (which together account for 75% of world exports of chrysotile fibre), have signed a Memorandum of Understanding (MOU), the objective of which is to supply chrysotile fibre only to those companies that demonstrate compliance with national rules and standards. It should be clear that the mines do not intend to become policemen. However, they do wish to encourage governments to put in place and enforce regulations, as well as encourage all users, large and small, to implement appropriate preventive and control programmes. Implementation of responsible-use will vary by country. However, an important cornerstone in all cases will be the principle of voluntary compliance, whereby companies will be asked to sign an Industry Voluntary Agreement (IVA), in which they make a commitment to make necessary improvements within a specific period of time and to provide an annual report demonstrating compliance with national regulations. Governments will be asked to undertake inspections of all of those companies that do not sign the IVA. Termination of supply would be a measure of last resort that will be imposed only after consultation with the national authorities.

The chrysotile industry recognizes that there will be a need for technical assistance as well as education and training programmes, including:

• National workshops on prevention;
• Plant visits with experts to provide advice on preventive and control measures;
• Training of specialists in industrial health and safety;
• Technical assistance in opening laboratories;
• Introduction to international methods and standards for counting asbestos fibres in the air.

With this MOU, the chrysotile asbestos industry has committed itself to promoting the health of workers and ensuring that controlled use becomes a reality worldwide. The programme is very ambitious, requiring close cooperation between producing and consuming countries. Accordingly, each mine has also agreed to seek its government's support in implementing the responsible-use programme at the international level. In March 1997, the Government of Canada signed an agreement to this effect with Canada's two operating chrysotile mining companies, LAB Chrysotile and JM Asbestos.

9 questions and answers on chrysotile and health

1. Is there evidence for a difference in biological potency between chrysotile asbestos and the amphibole fibres types?
   
   
2. Is there evidence for a difference in potency of fibres according to fibre length?
   
   
3. What is the risk associated with the presence of asbestos at concentration levels found in the general environmental air?
   
   
4. Asbestos in the workplace: Can asbestos be handled without undue risk to the workers? What is the risk to workers handling chrysotile asbestos at today's controlled exposure levels?
   
   
5. Can exposure to one single asbestos fibre kill?
   
   
6. Asbestos in Water: Does the use of asbestos-cement pipes contribute significantly to the presence of asbestos in water? Is there a risk associated with the presence of asbestos in drinking water?
   
   
7. Asbestos substitutes: Non-asbestos fibrous materials are used extensively, and are often proposed as substitutes for asbestos. In which areas of application are these materials used? Is there evidence available indicating biological activity of non-asbestos fibrous materials?
   
   
8. Asbestos friction materials: What is the contribution to the general environment resulting from the use of asbestos in friction materials?
   
   
9. Fibre-cement construction materials: What is the contribution to the environment resulting from the use of chrysotile in fibre cement materials?

SEE ALSO... Science and Decision Making: Should We Use Chrysotile Asbestos? Understanding Mesothelioma Controlled use of chrysotile