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NATIONAL
GUIDELINES FOR ASBESTOS Introduction Asbestos is the commercial name for a group of natural fibrous silicates, which have no common physical or chemical properties and are for practical reasons divided in two groups: chrysotiles and amhpiboles (1). Chrysotile asbestos accounts for more than 90% of all asbestos consumption in the world. Occupational exposure constitutes a serious health risk for workers employed in mining of asbestos ore, production and manufacturing of asbestos fibres, disposal of asbestos containing wastes, shipyards, brake and clutch repair, and other industries (2). Workers are only exceptionally exposed to chrysotile alone, since chrysotile always contains at least traces of amphiboles. Exposure to asbestos is associated with the development of certain diseases, notably asbestosis, diffuse malignant mesothelioma and cancers of the: lung, oral mucous, larynx, pharynx, gastro-intestinal tract and kidney (3). After the year 1990, the so-called amphibole hypothesis stirred up a great deal of discussion (4, 5). Its advocates maintain that chrysotile fibres have a low carcinogenic potential, especially when compared with amphiboles. A number of studies were carried out all over the world in an attempt to evaluate the influence of chrysotile alone on the development of lung cancer and mesothelioma (6, 7, 8, 9, 10, 11). The Collegium Ramazzini declared chrysotile as a cause of mesothelioma and lung cancer. As a result of these discussions, many countries across the world where asbestos is still used at present have adopted different recommended values for chrysotiles and amphiboles.
In
Slovenia, the use of asbestos was banned by law in 1996. At that time
the Ministry of Health was set the task to draw up national guidelines
for asbestos. As a basis for the guidelines, the Ministry sponsored
a study, which was to provide answers to the following questions:
The results of the study would be used by the government in drawing up the national guidelines and regulations for work with asbestos and for the detection and monitoring of asbestos-related occupational diseases (12). Methods The Ministry appointed a group of researchers to carry out the study. Information was gathered by the "snowball" method. For 11 companies, data on the use of asbestos in the production process were obtained from the Board for Asserting the Right to a Non-standardized Pension. On the basis of this information, further potential users of asbestos were identified in the following industries: electronic and electrical industry, shipbuilding, construction, manufacture of household appliances, oil refinery, car workshops where brakes and clutches were repaired, etc. Data on the import of asbestos into the country were obtained also from the Ministry of Health, which received requests for asbestos import from companies in 1998, the first year after use of asbestos had been banned. Namely, Ministry of Health exceptionally allowed the import of asbestos temporary to some companies that were not able to replace asbestos with non-toxic material in short time. Next, the customs authorities were asked to provide information on importers of asbestos and asbestos-containing products for the year 1997, the last year before the introduction of import-export licenses. All identified asbestos users were asked to complete a questionnaire inquiring about asbestos production, workers' exposure, air monitoring information, asbestos-containing wastes, use of protective equipment, and possible substitution of asbestos with a less hazardous substance. Data on the occurrence of mesothelioma and lung cancer in Slovenia were obtained from the Cancer Registry at the Institute of Oncology in Ljubljana. Information on occupational diseases was provided in the Institute of Occupational, Traffic and Sports Medicine. Results Approximately 670,000 tons of asbestos was imported into Slovenia in the period 1946-1996. This was mostly white asbestos, chrysotile. Separate data for white asbestos and amphiboles are available only for Salonit Anhovo, which imported most of the above quantity, i.e. about 61,400 tons, including more than 70,000 tons of amphiboles. From the total quantity of asbestos imported into Slovenia, it is evident that 89% of all asbestos was used by Salonit Anhovo . As shown by the figure 1, asbestos consumption in Slovenia peaked in the mid-seventies and early eighties and started to decline rapidly after 1982. The graph representing the total consumption closely follows the graph illustrating the consumption by Salonit. However, data on the second largest consumer, Donit, show that its peak consumption was shifted slightly into the eighties, attaining the highest level in the period 1982-1987. Izolirka, another major user of asbestos, has no available data on asbestos consumption, but the quantities used may be estimated from the production data, suggesting that the peak consumption occurred in the late eighties and early nineties. Slovenian factories manufactured a variety of asbestos products: corrugated sheets, sheets for gaskets, asbestos millboard, pipes, plasters, pastes, glues, etc. Asbestos was used as a construction and insulation material, asbestos textiles, engine gaskets, industrial gaskets, filters and insulation tapes; it was built into rail cars, boilers and brake linings, etc. In the study, the authors also estimated the quantity of asbestos products that have remained in Slovenia. This information is important because, in conjunction with data on the useful life of individual products, it forms the basis for estimating the quantity of asbestos products that are currently present on the territory of Slovenia. Asbestos products have a lifetime of 1 to 45 years. Some asbestos-containing materials are permanently installed in buildings. The expected life of products that were manufactured in greatest quantities ranges from 35 to 45 years, which means that most of these products are still in use at present, although their lifetime is running out. This also means that approximately the same quantities of asbestos will soon land on refuse dumps. Among asbestos-manufacturing plants, train company TvT had the largest number of workers. Salonit Anhovo was the second largest employer, all the other companies being much smaller. In Salonit, an estimated 300 to 600 workers, mostly employed in cement production, were directly exposed to asbestos. In TvT, the number of directly exposed workers is difficult to assess, as the areas where asbestos was used were not separated from other areas. However, TvT management estimates that about 1200 workers were exposed to asbestos after the year 1965. In Termika, the number of directly exposed workers was probably similar as in Salonit, but the majority was employed outside Slovenia, in different parts of the former Yugoslavia. The combined presentation of the number of workers employed in asbestos industry, the number of directly exposed workers and the quantity of asbestos used shows very similar fluctuations. However, compared to the other variables, the number of directly exposed workers is much smaller and so the differences are more difficult to perceive. From the companies the researchers obtained lists of all employed workers and list of those who were directly exposed to asbestos in the mid-eighties. In this way, they obtained a cohort of directly exposed workers and a cohort of potentially exposed workers. The cohorts will be followed over the coming years. Since
the adoption of regulations on asbestos-related occupational disease
in 1997, two interdisciplinary teams of experts evaluate all cases
of asbestos disease. In the period 1998-2002, the teams confirmed
1331 patients with occupational asbestos disease. Among them were
363 asbestosis, 932 patients with pleural plaques, 18 had occupational
lung cancer and 18 occupational mesothelioma. Discussion and conclusion The following 14 large asbestos-manufacturing plants provided sufficient information to be included into the analysis: Donit Laminati, Donit Pletilnica, Donit Tesnila, Filtrauto, Fragmat, Izolirka, Kolektor, Salonit, Sinter, Termika, TiT Tesnila, TMT Tesnila, TVT Tirna vozila in WV Term. We are quite confident, that the analysis covered more than 95% of all asbestos consumption in Slovenia and most probably also a similar proportion of workers exposed to asbestos over the past 35 years. It is true that, according to the available information, some 30 companies in Slovenia used asbestos. However, compared to the above-listed companies, those that were excluded form the survey had only minimal consumption. Clearly, this does not rule out morbidity among workers employed in smaller plants. Morbidity depends on exposure, which does not always correlate with the quantity of asbestos used, but is also related to the job, type of exposure, the material used (pure or mixed asbestos) and, last but not least, the protection of workers. The situation with environmental pollution is of course somewhat different. Pollution is obviously most severe in environments with the highest level of production and the greatest quantities of asbestos wastes; it is also influenced by the method of storage an/or disposal of wastes. Of the 14 companies included in the survey, three produced gaskets and the rest other products, ranging from pipes and sheets to asbestos textiles, glues, filters, brake linings etc. The first asbestos-manufacturing plants were established already in the 19th century, and ten were founded after World War II. Asbestos was always imported into Slovenia, most frequently from Canada, Russia, South Africa, Bosnia and Serbia. Two plants purchased asbestos from Salonit. It is interesting to look at the safety measures used in the workplace: seven of the 14 plants had no safety measures whatsoever. Five companies used rotation of workers, which is a highly unsuitable practice since more people than necessary are exposed. Two companies used various unwritten measures, but these were instituted only after 1970 and were probably never practiced very consistently. Interestingly, in 11 companies internal regulations required some form of protection (respirator or mask), but it was apparently not obligatory, and the workers were not sufficiently aware of the need to use protective devices, nor was non-compliance sanctioned in any way. In one company, regular medical examinations were performed at comparatively brief intervals already before 1960. Apparently, periodic examinations were soon introduced also in other plants, but it is questionable if they were sufficiently focused and not too general. Only three companies had internal regulations or rules referring specifically to work with asbestos. Considering how long asbestos has been used in Slovenia and how long we already have and will continue to come in contact with this material, we may expect asbestos-related diseases to be prevalent in our area for at least another 30 years.
Bibliography:
Sažetak NACIONALNE SMJERNICE ZA AZBEST
Slovenija je zabranila upotrebu azbesta u privredi zakonskom odredbom
1996.godine. |
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