The use of asbestos in roof tiles and water tanks is a very controversial issue, there is a wide divergence of opinions, as it is a matter that involves conflicts of political, economic, environmental and health.
In Brazil, Federal Law 9,055/95 allows the controlled use of asbestos in the country. However, two states prohibit the use of materials that contain any type of asbestos, they are: Rio Grande do Sul and São Paulo.
Therefore, the Federal Supreme Court (STF) began to judge on October 31, 2012 the use of asbestos in Brazil. One of the actions that will be judged is that the laws of these two states would be contrary to federal law.
Several arguments were presented in favor and against the use of asbestos and, therefore, the judgment ended in a draw and no prediction of when it will be resumed.
On the side that favored the use of asbestos were the lawyers from the asbestos factory, workers who fear lose their job, the Ministry of Development, Industry and Foreign Trade and the Ministry of Mines and Energy.
On the side against the use of asbestos were representatives of the Public Ministry of the Brazilian Bar Association (OAB), sick workers due to exposure to asbestos and the Ministries of Health, Environment and Welfare Social.
As citizens, we need to understand the factors involved in the use of this mineral in construction products so that we can choose one side of the issue. Therefore, we will present in this text the chemical composition of asbestos and what are the main arguments presented by those who defend and those who protest against its use.
- Chemical composition of asbestos:
The word asbestos comes from the Latin asbestos, which means “incorruptible”. But, this mineral is also called asbestos, which comes from the Greek “non-combustible”. All of the more than 30 types of natural fibrous silicates found in the soil are called asbestos, with only six being of commercial interest. The two main groups of asbestos rocks are:
1. Streamers (white asbestos - correspond to more than 95%of all geological manifestations on Earth): consisting of chrysotile mineral (Mg3Yes2O5(OH)4);
2. Amphiboles (brown, blue and other asbestos - correspond to less than5% of all mined asbestos in the world): consisting of tremolite minerals (Ca2mg5Yes8O22(OH)2) and amosite ((Fe, Mg, Ca) OSiO2. n H2O).
This mineral has several important physicochemical properties, such as:
- high mechanical strength;
- high resistance to high temperatures;
- is insulating;
- is very flexible;
- resistant to attack by acids, bacteria, alkalis;
- is non-combustible (as shown by the meaning of its name);
-It is easy to be woven.
These and other properties cause this fiber to be used in the manufacture of tiles, tanks, water tanks, in various civil construction products and to thermally insulate machines and equipment.
- Arguments against the use of asbestos:
- Several studies show that asbestos is a fiber proven to be carcinogenic, breathing the dust from its fibers causes inflammation of the cells in the alveoli, evolving into a series of incurable and progressive diseases. One of the diseases that breathing tiny asbestos fibers can lead to is asbestosis, also known as stone lung, because it causes the lung to harden. In addition, there are cancers in the gastrointestinal tract and the development of mesothelioma, a rare, aggressive and malignant tumor that affects the tissues that line the chest and abdomen. An aggravating factor is that symptoms of these diseases can take up to 20 years to appear.
- Workers are the main victims of the development of these diseases, as asbestos fibers can be inhaled in large quantities in the extraction process or in the natural degradation of fiber cement products.
But users of products made from asbestos can also become contaminated, when, for example, a tile falls and breaking, or even ingesting water from the water tanks of this material, as there is constant friction between it and the water tank. Unfortunately, the workers themselves are the biggest consumers of these products. Not to mention the contamination of the wives of these workers, who often wash their work clothes and inhale the fibers as well.
- Virtually all European countries have banned the use of any type of asbestos in their territories. Furthermore, many countries, such as Canada, produce asbestos and practically do not use it in their territory, but export it to poor or developing countries. Being well aware of the dangers of using this mineral, they look for alternative materials that can be used instead.
- There are allegations that the expert who presented the study that said that chrysotile-type asbestos does not actually cause cancer was financed by the Brazilian asbestos industry.
- Studies, like the one made by Unicamp shown on the website of INCA, reveal that it is feasible to ban asbestos and that the economic impacts would not be as significant, as the installed industries already have technology to replace the material at competitive costs. This study reveals that the price difference would not exceed 10% and that even products with asbestos can be more expensive than those without asbestos.
- Arguments in favor of the use of asbestos:
- Asbestos manufacturers and advocates say that chrysotile asbestos (white asbestos) is not responsible for the cancer of several workers in the past, but amphibole type asbestos (which is prohibited in Brazil). It is said that the biopersistence (time of fibers remaining in the lung before being eliminated) of chrysotile is completely different from that presented by amphibole. Amphibole fibers have a significant permanence, while chrysotile is rapidly eliminated from the lung.
- In the past, as there was not enough information, workers were totally exposed to these fibers, but today there are laws that regulate extraction, industrialization, use, marketing and transport.Among them are the following:
- the tolerance limit for breathable fibers at 2 fibers/cm3 (factories ensure that regular monitoring is carried out to allow them to operate at limits lower than this);
- every six months an environmental assessment is carried out and the results are disclosed for the employees to know;
- workers wear personal protective equipment, as well as work clothes that are changed twice a week and washed under the responsibility of the company;
- workers have double changing rooms, so that work clothes can be separated from ordinary clothes;
- workers undergo medical examinations and clinical evaluation on admission, periodically and after dismissal for up to 30 years, at a frequency determined by the time of exposure: annual, for those who were exposed to more than 20 years old; every two years, between 12 and 20 years; every 3 years, below 12 years.
- The ban on the use of asbestos will bring great economic damage, thousands of workers will lose their jobs and Brazil will lose 30 million dollars a year that are obtained by exporting the product. The biggest impact will be in the region of Minaçu, Goiás, where the largest asbestos mine under exploration in Brazil is located.
- Wet extraction methods are currently used that virtually eliminate the danger of occupational cancer.
- Asbestos is a cheap material and other materials that would be used instead, as possible alternatives, would not be viable for market competition, as they would be more expensive, less durable and require many studies. The manufacture of this product means that civil construction is cheaper, especially for low-income families.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/pros-contras-uso-amianto.htm