Asbestos: What is it?
Asbestos is a substance belonging to the category of fibers. They are elongated bodies in which length prevails over diameter and width. We have two distinct types of fibers, natural ones, that is, found in nature (asbestos, zeolites, sepiolites) and artificial ones (mineral wool, rock wool, ceramic fibers), which are mineral fibers, produced by man through technological processes, and which today have almost completely replaced them.
Why is it dangerous?
Asbestos not only causes asbestosis, but also other diseases, some very serious.
Its manipulation determines the release of the fibers, which can disperse in the air and - once they come into contact with humans - penetrate and progress along the airways.
Asbestos, therefore, given the size of its fibers, is a substance that is easy to inhale. These fibers are also bio-resistant, that is, before being destroyed by the organism with which they came into contact, they require a lot of time, so they can cause harm.
Employments
Asbestos was widely used, especially years ago, because it is fire resistant, an excellent sound absorbent, and is also a dielectric. Its properties of resistance to acids, microorganisms and wear, its flexibility and possibility of being "woven" into very ductile structures, making it widely used on an industrial level. For example, we can find it in railway carriages, ships, in asbestos-cement and in the textile industry.
Types of asbestos
There are different types of asbestos, which cause different types of pathologies. Its fibers, for simplicity, can be divided into two large groups:
• Serpentine group: it is represented by chrysotile (white or gray asbestos), and is much more used than other types of asbestos. In fact, it corresponds to about 93% of world production, and this is good because it is less harmful than the second group. It is produced mainly in South Africa, the Russian Federation, Canada, Yugoslavia, Europe (Corsica and, more than half only in Italy, especially near Turin).
• Amphibole group:
Crocidolite or blue asbestos = iron silicate. The most dangerous of all. It is of Australian origin, and was used in England for the construction of gas masks for military use.
Amosite or brown asbestos = iron and magnesium silicate. Very dangerous, but less than crocidolite. There were shipbuilding workers in the USA and Canada.
Anthophyllite = magnesium silicate
Tremolite = magnesium and calcium silicate. Used in Turkey as a material for building houses.
Actinolite = calcium, magnesium and iron silicate.
Types of exposure
Exposure to asbestos was recorded in about 3,000 types of activities. The main ones are:
- Extraction of asbestos fibers from mines and quarries;
- Paint mixes;
- Reinforced concrete industry;
- Paper industry (asbestos cartons): paper, coatings for stoves, heaters, booths, film production;
- Textile industry: fireproof clothing and fabrics, such as theater curtains;
- Industry of friction materials (rolling stock, railway, ships) and the production of brakes and clutches (mainly elevators);
- Chemical industry: production of filters;
- Thermal and acoustic insulation industry;
- Asbestos-cement pipes for pipelines and construction industry (roofs, flues, pipes).
It should be noted that there are countless types of exposure to "asbestos, not as frequent as those mentioned above and defined for this reason"unusual ". Non-occupational sources of contamination may be due to proximity to production sites, the use of asbestos facilities in old homes and workshops, fibers brought home on clothing by miners or industrial workers, and environmental contamination.
Legislation
There has been extensive legislation on asbestos for many years.Since 1992 a very strict law has been in force which, throughout the national territory, prohibits the extraction, import and export, marketing and production of asbestos or products containing it. Exposure to this substance is today limited only to workers employed in the activities of removal of the same from still contaminated places, and in reclamation. For these activities, precise rules for the protection of workers are envisaged concerning in particular information, the use of personal protective equipment and limited access to work areas. The means of personal protection from asbestos concern clothing (self-contained breathing apparatus, hood , gloves, overshoes), double filter masks (for ultra-fine powders) and disposable masks for asbestos powders.
However, even if the 1992 law prohibits its use, today it makes sense to talk about asbestos pathologies, both because there are still some exposed subjects, who are the same workers for removal and reclamation (even if in reality it is possible , adopting the appropriate precautions, to obtain the zeroing of the risk during these maneuvers) but above all, a real medical problem is given by the considerable period of latency between the exposure and the appearance of the pathology (which occurs in the ex-exposed). For example , knowing that asbestos lung cancer has a latency period of about 20-25 years and that of pleura (mesothelioma) of about 30, assuming that a person started working in risky places in the "80s, we can see asbestos pathologies until 2010-2015.
Continued: Diseases caused by "asbestos"
