Document J3zJzgvOZ3DbOeKLo8mq5Q4ve
Elimination of asbestos-
related diseases
World Health Assembly Resolution 58.22 from 2005 on cancer prevention and control urged Member States to pay special attention to cancers for which avoidable exposure is a ffctor, particularly exposure to chemicals ar the workplace and the environment. Asbestos is one of the mosr importanr occupational carcinogens causing abour half of the deaths from occupational cancer (1;2). Furthermore, the Thirteenth Session of the Joinr ILO/WHO Committee on Occupational Health in 2003 recommended thar special attention should be paid to the elimination of asbestos-related diseases (3). The term "asbestos" designates a group of naturally occurring fibrous serpentine or amphibole minerals with currena or historical commercial usefulness due to their extraordinary tensile strength, poor hear conduction, and relative resistance to chemical attack. The principal varieties of asbestos are chrysotile, a serpentine material, and crocidolite, amosite, anthophylite, tremolite and actinolite, which are amphiboles (4). Exposure to asbestos causes a range of diseases, such as lung cancer, mesothelioma, and asbestosis (fibrosis of the lungs), as well as pleural plques, thickening and effusions (5;6). There is also evidence thar h causes lryngeal and possibly some other cancers (7).
Exposure to asbestos and its impacts on public health are substantial
Exposure to asbestos occurs through inhalation of fibres primarily from contaminated air in the working environmenr, as well as from ambient air in the vicinity of poinr sources, or indoor air in housing and buildings containing friable asbestos materials. The highesr levels of exposure occur during repackaging ofasbestos containers mixing with other raw materials and dry cutting of asbestos-containing products with abrasive tools. Exposure can also occur during instaHt^n and use of asbestos-containing products and maintenance of vehicles. Friable chrysotile and/or amphibolecontaining materials are still in plce in many buildings and continue to give rise to exposure to both chrysotile and amphiboles during maintenance, alteration, removal and demolition (5). Currently abou 125 million people in the world are exposed to asbestos ar the workplce (1). According to global estimates aa leasa 90,000 people die each year from asbestos-related lung cancer, mesothelioma and asbestosis resulting from occupational exposures (1;2;8). In addition, h is believed thar several thousands of deaths can be attributed to other asbestos-related diseases as well as to nonoccupational exposures to asbestos. The burden of asbestos-related diseases is still rising, even in countries that have banned the use of asbestos in the early 1990s. Because of the long lltency periods attached to the diseases in question, sopping the use of asbestos now will only resuh in a decrease in the number of asbestos-related deaths after a number of decades.
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All types of asbestos cause cancer in humans
Asbestos (actinolite, amosite, anthophyllite, chrysotile, crocidobte and tremolite) has been classified by the International Agency for Research on Cancer as being carcinogenic to humans (9). Exposure to chrysotile, amosite andanthophyllite asbestos and to mixtures containing crocidobte results in an increased risk of lung cancer (9). Mesotheliomas have been observed after occupational exposure to crocidobte, amosite, tremolite and chrysotile, as well as among the general population living in the neighbourhood of asbestos factories and mines and in people living with asbestos workers (9).
The incidence of asbestos-related diseases is related to fibre type, fibre size, fibre dose and to industrial processing of the asbestos (6). No threshold has been identified for the carcinogenic risk of chrysotile (5). Cigarette smoking increases the risk of lung cancer from asbestos exposure (5; 10).
Chrysotile is still widely used
Asbestos has been used in thousands of products for a vast number of applications, such as roofing shingles, water supply lines, fire blankets, plastic fillers, and medical packing, as well as dutches and brake linings, gaskets and pads for automobiles. As a result of increasing health concerns, the use of asbestos has declined in many countries. The use of crocidobte and products containing this fibre as wdl as sprayng of all forms of asbestos have been prohibited under the ILO Convention No. 162 from 1986 Concerning Safety in the Use of Asbestos. However, chrysotile asbestos is still widdy used, with approximatdy 90% being employed in asbestos-cement building materials, the largest users of which are developing countries (11). Other remaining uses of chrysotile are friction materials (7%) textiles and other applications (11).
To date more than 40 countries, including all member states of the European Union, have banned the use of all forms of asbestos, including chrysotile.Other countries have introduced less stringent restrictions. However, some countries have maintained or even increased their production or use of chrysotile in recent years (12). World production of asbestos in the period 2000-2005 has been relatively stable, at between 2,050,000 and 2,400,000 metric tonnes per annum (13; 14).
WHO recommendations on prevention of asbestos-related diseases
Bearing in mind that there is no evidence for a threshold for the carcinogenic effect of asbestos and that increased cancer risks have been observed in populations exposed to very low levels (5;9), the most efficientway to eliminate asbestos-related diseases is to sop using all types of asbestos. Continued use of asbestos cement in theconstruction industry is a particular concern because the workforce is large, it is difficult to control exposure and in-place materials have the potential to deteriorate and pose a risk to those carrying out alterations, maintenance and demolition (5). In its various applications, asbestos can be replaced by some fibre materials (15) and by other products which pose less or no risk to health.
Materials containing asbestos should be encapsulated and, in general it is not recommended to carry out work that is likely to disturb asbestos fibres. If necessary, such work should be carried out only under strict preventive measures to avoid exposure to asbestos, such as encapsulation, wet processes, local exhaust ventilation withfiltration, and regular cleaning. It also requires the use of personal protective equipment - special respirators, safety goggles, protective gloves and clothing - and the provision of special facilities for their decontamination (16).
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WHO is committed to work with countries towards elimination of asbestos-related diseasesin the following strategic directions:
- by recognizing that the most efficient way to eliminate asbestos-related diseases is to sop the use of all types of asbestos;
- to provide information about solutions for replacing asbestos with safer substitutes and developing economic and technological mechanisms to stimulate its replacement;
- to take measures to prevent exposure to asbestos in place and during asbestos removal (abatement);
- to improve early diagnosis, treatment, social and medical rehabilitation of asbestos-related diseases and to establish registries of people with past and/or current exposures to asbestos.
WHO strongly recommends planning for and implementation of these measures as part of a comprehensive national approach for elimination of asbestos-related diseases. Such an approach should also include: developing national profiles; awareness rating; capacity building; an institutional framework; and a national plan of action for elimination of asbestos-related diseases. WHO will collaborate with ILO on the implementation of the Resolution on Asbestos, adopted by the Ninety-fifth Session of the International Labour Conference (17) and will work other intergovernmental organizationsand civil society towards elimination of asbestos-related diseases worldwide.
References
(1) Concha-Barrientos M et al. Selected occupational risk factors. In: Ezzati M et al, eds. Comparative quantification of health risks: global and regional burden of diseases attributable to selected major riskfactors. Geneva, World Health Organiza on; 2004: 1651 -1801.
(2) Driscoll T et al. The global burden of diseases due to occupational carcinogens. American Journal of Industrial Medicine, 2005, 48(6):419-431.
(3) ILO, WHO. Report of the Committee JCOH/2003/D.4. Thirteenth Session of the Joint ILO/WHO Committee on Occupational Health. Geneva, International Labour Office, 2003.
(4) WHO. Asbestos. In: Air Quality Guidelines, 2nd ed. Copenhagen: WHO Regional Office for Europe; 2000.
(5) WHO. Environmental Health Criteria 203: Chrysotile Asbestos. Geneva, World Health Organization; 1998.
(6) WHO. Environmental Health Criteria 53: Asbestos and Other Natural Mineral Fibres. Geneva, World Health Organization, 1986.
(7) Committee on Asbestos: Selected Health Effects, Board on Population Health and Public Health Practices. Asbestos: Selected Cancers. Washington, D.C., The National Academies Press, 2006.
(8) Driscoll T et al. The global burden of non-malignant respiratory disease due to occupational airborne exposures. American Journal ofIndustrial Medicine, 2005, 48(6)432-445.
(9) IARC. IARC Monographs, Supplement 2: Asbestos. Lyon, International Agency for research on Cancer, 1987.
(10) IARC. IARC Monographs Vol. 83: Tobacco Smoke and Involuntary Smoking. Lyon, International Agency for Research on Cancer, 2006.
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(11) Perron L. Chrysotile. In: Canadian Minerals Yearbook, 2003.Ottawa, Natural Resources Canada, 2003:18.1 18.11.
(12) Virta RL. Worldwide asbestos supply and consumption trendsfrom 1900 to 2000: Open-File Report 03-83. U.S. Department of the Interior, U.S. Geological Survey, 2003.
(13) Virta RL. Asbestos. In: USGS 2005 Minerals Yearbook. U.S. Department of Interior, 2006:8.1-8.6. (14) Virta RL. Asbestos. In: USGS 2004 Minerals Yearbook. U.S. Department of the Interior, 2005:8.1-8.3. (15) WHO. Summary Consensus Report of WHO Workshop on Mechanisms of Fibre Carcinogenesis and Assessment
of Chrysotile Asbestos Substitutes, 8-12 November 2005, Lyon, France. Geneva, World Health Organization, 2005. (16) IPCS. Chrysotile: International Chemical Safety Card 0014. International Programme on Chemical Safety, Geneva, 1999 (17) Resolution Concerning Asbestos. In: Ninety-fifth International Labour Conference, Geneva, 31 May - 16 June 2006. Report of the Committee on Safety and Health. Geneva, International Labour Conference (Provisional Record 20), Annex 20/69.
World Health Organization 2006
WHO/SDE/OEH/06.03 September 2006 All rights reserved. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published materialis being distributed without warranty of any kind, either expressed or imped. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. Printed by the WHO Document Production Services, Geneva, Switzerland
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