ABSTRACT
Asbestos, known to possess unique physicochemical and mechanical properties, has been used for many different applications such as an insulator in personal protective equipment (PPE), a strength amplifier in cement, its thermal stability to make heat or flame resistant material, fabrication of papers, friction products in brake or clutch pads, vinyl or asphalt tiles, asphalt road surfacing and many more. However, due to several recent restrictions most of the asbestos related material applications have been abandoned and the remainders are pursued under strict regulated conditions. One of the most adverse nature of asbestos is its toxic nature and is related to diseases such as asbestosis, asbestos-related lung cancer and mesothelioma. In this paper we study the asbestos composition and structure to understand why its chemical and physical properties are unique making it desirable in the industries it is being used in. We examine the diseases of asbestosis, lung cancer and mesothelioma to understand their relation to asbestos and what renders the latter toxic, and discuss different methods of safeguards against asbestos toxicity starting with the current United States’ legislation pertaining to asbestos use, its removal and disposal practices. Additionally, we cover research proposed on asbestos abatement for at least the last 10 years. We also investigate asbestos related alternatives for industrial purposes and propose different strategies and materials for future research as additional asbestos safeguards.
INTRODUCTION
Asbestos is a mineral fibrous material that has been well explored for centuries due to its useful properties such as incombustibility, thermal stability, resistance to biodegradation, and low electrical conductivity. Asbestos is a Greek word άσβεστος (ash-ve-stos) which means inextinguishable and is comprising a group of six minerals: chrysolite, amosite, crocidolite, anthophyllite, tremolite and actinolite (“Asbestos: What Is Asbestos,” 2021). Asbestos minerals originate from metamorphic rock comprised of minerals with similar properties. The majority of asbestos is being produced by Russia with 55% of global production followed by Canada with 20%. South Africa, China, USA, Zimbabwe, Italy and Brazil produce less than 4% of worldwide asbestos (Habashi, 2002). Most of the asbestos used in the United States is imported from Canada.
Figure 1
Asbestos Fiber
Note: Asbestos fiber under the microscope. (Habashi, 2002)
Asbestos is divided into two families: serpentine and amphibole. The difference between these two families lies in the form of their fibers. The serpentine asbestos family is characterized by the curly fibers, while the amphibole by straight and jagged fibers (Jones, 1890). Out of the six constitutes of asbestos, Chrysolite is the only one that belongs to the serpentine while the rest belong to the amphibole asbestos family. Asbestos are silicates, indicating the presence of silicon and oxygen atoms in its molecular formula. The silicate minerals crystallize in packs of hundreds of thousands of strong, flexible fibrils to form the fibers, as shown in Figure 1. These fibers deposited in the mineral form, are extracted by mining operations and are easy to separate.
Figure 2
Hydrated Magnesium Silicate Sheets
Note: Hydrated magnesium silicate sheets rolled in asbestos fibers. (Habashi, 2002)
Chrysolite, also known as “white asbestos”, is the most commonly used mineral of all constituting 95 % of asbestos applications. It is a hydrated magnesium silica with the formula of 3MgO.2SiO2.2H2O, alternatively Mg3(Si2O5).(OH)4. The tetrahedral silicate ions (SiO4)4- is the critical element responsible for creating a variety of silicates structures due to the numerous different combinations it can create with its surrounding atoms. The presence of both intermolecular and intramolecular bonding structures create the hydrated magnesium sheet that rolls up around itself like a scroll, forming the fibrils (monofibers). When hundreds of such monofibers are compacted together in parallel arrangement, they form one white asbestos fiber (Habashi, 2002b). An example of the forming process is illustrated here, shown in Figure 2.
PROPERTIES
Asbestos’ uniqueness lies on the fact that many of its different chemical and physical properties combine at the same time, making it a versatile and cost-effective material to use. Many different applications such as advanced material requirements could be fulfilled by the use of only one material instead of multiple ones that would meet the proper requirements for each application.
Asbestos is a natural insulator making it very useful in industrial applications (Jones, 1890). It is commonly used in construction for wiring and electrical insulation purposes because it prevents the creation of sparks due to electrical charges flow that could harm the people.
It is mostly inert material meaning it resists reactions with a majority of other chemical substances. Consequently, materials containing asbestos are not affected by corrosion. They can be left in nature at any environmental conditions of temperature and pressure without making any significant changes in their structures and chemical composition . They resist decay and moisture (Jones, 1890). This property makes asbestos highly desirable in the construction and chemical industries. For example, because of these properties many roofing materials contain asbestos.
Asbestos can be chemically converted into a non-fibrous nature by simple processes such as decomposition. This process is easily done by the mixing of asbestos with a slightly acidic solution of a pH < 6. The magnesium in chrysolite asbestos is extracted when the hydronium ions (H3O+) in the acid solution reacts with the hydroxyl ions (OH-) in the basic magnesium hydroxide, Mg(OH)2 solution (Sugama et al., 1998). The hydrated magnesium sheet that constitutes the fiber of chrysolite asbestos falls apart and therefore, the fibrous nature of asbestos is destroyed. Magnesium-free asbestos becomes fragile but keeps its shape (Habashi, 2002b).
In physical terms, asbestos is a heat resistant. It is able to withstand high temperatures with undergoing minimal changes up until about 500 °C. Beyond that temperature asbestos substances undergo major transformations depending on the type of asbestos mineral. For example, chrysolite asbestos loses water when heated to a temperature range of 600-780 °C due to dehydroxylation process. The product so obtained crystallizes if the temperature is further raised to 800-850 °C to form the forsterite, Mg2SiO4, and silica, SiO2. These two products can then further combine to form enstatite Mg2(Si2O6) a material usually cut as gemstone, when the temperature is above 1000 °C (Habashi, 2002b).
Another physical property of asbestos is its durability. Asbestos is composed of fibers that are flexible and can be woven (Jones, 1890). The length and nature of the fibers depend on the type of asbestos. They have a small diameter of an order of 5-25 nm (nanometers) (Habashi, 2002b). While they are bundled together, they can be easily separated from one another. Its fibrous nature is exploited to make fabrics. These fibers, because they are stiff as steel, have high tensile strength explaining the durability of asbestos (IARC Working Group on the Evaluation of Carcinogenic Risk to Humans & Humans, 2012). Therefore, materials containing asbestos are used for structures supporting high numbers of loads. Moreover, asbestos is used in the textile industry for fabric production.
INDUSTRIAL USES
Asbestos has been historically used in construction and textile industries from ancient through medieval times to the industrial revolution, in which its use became widespread. In the United States, asbestos products were widely utilized from the late 1800s to 1980. Since then, asbestos-related regulations created because of the dangers it poses to human health, causes its production to decline.
Fibrous nature of asbestos combined with its heat resistance property makes it a prominent material in textile applications. Textiles made from asbestos can resist high heat with a threshold ranging anywhere between of 200-480 oC. Textiles containing asbestos are used to make heat resistive gloves and clothes for workers and firefighters to protect them against high heat exposure. In most cases, asbestos fibers are not long enough for the textiles’ woven process to successfully manufacture clothes. Therefore, asbestos is mixed with other types of fibers, for example cotton, to facilitate its woven process. Upon completion of final product, any remaining material is being destroyed by exposing the material to a high temperature (red heat) (Jones, 1890). It is rumored that because of the non-flammable nature of asbestos, any clothes made of asbestos was washed by passing them through fire.
In construction, asbestos is added to cement to increase the strength and durability of the latter. Asbestos considerably increases the tensile strength making it favorable over other materials for structures such as buildings and bridges. Asbestos fibers are employed as reinforcements; they prevent building members from cracking and slow down their failure. Furthermore, asbestos fibers are able to strengthen the materials without overloading the overall structure. Finally, its fire-resistant property plays an important role because as a fire retardant decreases the rate of fire can spread and therefore minimizes the fire damage in buildings and the environment.
ASBESTOS TOXICITY AND DISEASES
Asbestos left undisturbed and in stable condition is not toxic. The problem arises when asbestos is falling apart and the thin nano-fibers that are comprising it, separate themselves from the main body and become airborne. The naked human eye can only detect the relatively bigger dust particles, whereas the micron level or even smaller particles such as nano-sized particles cannot be detected by human eyes and so we need high resolving power microscopes that can easily establish whether a given dust contains asbestos and/or other carcinogenic fibers. The thin asbestos nano-fibers are very light in weight and can travel through the air and inhaled by humans, travel through our respiratory system and end up in our lungs. Once these fibers enter the human body, they adhere to our body tissues and gets accumulated in the tissue local areas restricting the organ’s normal functions. Because of the indestructible nature of these asbestos fibers, our bodies cannot remove them by natural means under physiological cellular environment. Usually, humans are exposed to asbestos fibers throughout their lives, and end up absorbing small quantities of asbestos fibers that do not cause any adverse effects. However, prolonged exposure to asbestos contaminated environments results in asbestos fibers accumulation in amounts exceeding the threshold of safety for the human body hindering human organs from functioning properly leading to diseases such as asbestosis, lung cancer, and mesothelioma (Solbes & Harper, 2018; “Asbestos: What Is Asbestos,” 2021).
Asbestosis
Asbestosis is caused when asbestos fibers entering our lungs attached themselves in certain areas of our lungs (alveoli) that are responsible for exchanging the carbon dioxide that has produced in our bodies, with oxygen by expanding and contracting. The asbestos fibers attached to that area clog and irritate the organ inhibiting the exchange of oxygen and carbon dioxide resulting in shortness of breath. At the same time, because the organ tries harder to function properly, it becomes scarred. As the asbestos fibers keep accumulating the organ becomes stiffer and stiffer, until it reached a point that it cannot expand and contract and thus not able to provide oxygen in our body by removing the carbon dioxide. Asbestosis is highly possible to lead to lung cancer and on rare occasions to mesothelioma (Solbes & Harper, 2018; “Asbestosis - Symptoms and Causes,” 2021).
Lung Cancer
Asbestos-related Lung Cancer is developed because the asbestos fiber lodged in lung tissues cause not only cellular but also genetic damage to the lung cells and in a sense the lung cells’ genetic “modified” code starts providing erroneous instructions for the recreation of new lung cells containing the erratic genetic code that will lead them in turn to reproduce new “erratic” lung cells, and so on and so forth. This constant development or “erratic” lung cells is called lung cancer. The process of modification and mutation of the genetic code can take decades to happen, but once it is completed cancer can occur in a matter of months or less, depending on the body’s constitution. It can also metastasize, transfer from lung tissues to other parts of the body, in an equally fast fashion (“Asbestos Lung Cancer: Causes,” 2021).
Figures 3 and 4
Frontal X-ray of Lungs
Note: Figure 3: Frontal x-ray of healthy lungs. Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 8090 (radiopedia.org, n.d.) Figure 4: Frontal x-ray of cancer infected lungs. Case courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 8857 (radiopaedia.org, n.d.)
Mesothelioma
Mesothelioma is a particular and rare case of asbestos-related cancer. It is malignant, aggressive (fast development and spread) and deadly as for the majority of the patients of mesothelioma, a cure is not possible. When lung cancer metastasizes, it can travel anywhere in the human body through our circulation system. One of the areas it can end up is the thin layer of tissue covering our internal organs. This thin layer of tissue is called mesothelium. Cancerous cells that have metastasized in mesothelium start developing and spreading fast leading to mesothelioma, and depending on which part of mesothelium is affected, mesothelioma can be categorized accordingly. For example, affected mesothelium covering the lungs is called pleural mesothelioma, affected mesothelium covering the abdomen is called peritoneal mesothelioma, etc. (Carbone et al., 2019; “Mesothelioma - Symptoms and causes,” 2020)
SAFEGUARDS AGAINST ASBESTOS TOXICITY
Archeological evidence suggests that asbestos has already been in use as early as 4000 B.C. (King, 2022), but its industrialization began after 1860 with 1878 being marked as the year when the effectiveness of asbestos related products was highlighted at the Paris University Exposition, resulting in their exponential increase of production and use in a worldwide scale (Spasiano & Pirozzi, 2017). Due to its properties, asbestos was convenient both financially and structurally to use in the construction field. And the more developments and advances were made industrially, the more asbestos was consumed. Specifically in the construction industry, many public and especially educational buildings (schools, colleges, universities) became contaminated with asbestos (King, 2022).
It was not until the 1960’s that asbestos became associated with the asbestosis, lung cancer, and mesothelioma diseases. After the discovery, countries around the world started addressing the asbestos’ hazards by gradually setting forth legislations pertains to its restriction from future projects. By the end of the 1970’s, asbestos consumption experienced a great decline due to the effect of legislation restricting its use and the public realizing its hazardous nature. By 2003, asbestos was totally banned within the European Union. In the United States, asbestos and its uses have been restricted but not totally banned, as there are still some commodity items that use asbestos as a component. (King, 2022)
The hazardous nature of asbestos prompted the industrial world to research for methods of either rendering asbestos non-toxic or finding appropriate materials to substitute it with.
United States Legislation: Asbestos-related Laws and Regulations
The leading federal agency in United States responsible for asbestos handling regulations is the Environmental Protection Agency (EPA) with 6 Asbestos-related laws and 7 Asbestos-related regulations. Other federal agencies that have Asbestos-related regulations are: the Occupational Safety and Health Administration (OSHA) setting standards for occupational safety and health standards of working conditions for United States’ workers; the Consumer Product Safety Commission (CPSC) that issues bans and/or restrictions on asbestos-containing products posing a fire, chemical, electrical, mechanical hazard, or can pose a threat to children; lastly, the Mine Safety and Health Administration (MSHA) setting regulations pertaining to working conditions for miners (United States Environmental Protection Agency, 2021).
EPA asbestos-related Laws
Toxic Substances Control Act (TSCA) - 1972
The Toxic Substances Control Act (TSCA) provides definitions for all hazardous and toxic substances, including asbestos and its sub-varieties: chrysotile; crocidolite; amosite; anthophyllite; tremolite; actinolite (United States Environmental Protection Agency, 2021).
Safe Drinking Water Act (SDWA) - 1974
The Safe Drinking Water Act (SDWA) is a major law governing threshold levels of pollutants, including asbestos, in the drinking water setting the standards ensuring quality for the public (United States Environmental Protection Agency, 2021).
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) - 1980
The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) - also known as Superfund – focuses on addressing the release or potential release of hazardous wastes, such as asbestos, to the environment (United States Environmental Protection Agency, 2021).
The Asbestos Hazard Emergency Response Act (AHERA) - 1986
Asbestos Hazard Emergency Response Act (AHERA), which is part of the TSCA - Title II, requires the EPA to promote regulations that make all local educational agencies inspect their buildings for asbestos contaminated building materials, and prepare plans for abatement and prevention/reduction of asbestos hazards. Additionally, this law required the accreditation of people conducting inspections and activities pertaining to prevention and decrease of asbestos related hazards (United States Environmental Protection Agency, 2021).
Asbestos Information Act - 1988
Another law crucial for the public to know which products are asbestos contaminated, and, therefore, aiding the prevention and reduction of asbestos hazards, is the Asbestos Information Act with which manufacturers and companies are required to report production and commerce of asbestos contaminated products (United States Environmental Protection Agency, 2021).
Clean Air Act (CAA) – 1990
The Clean Air Act (CAA) is a crucial law responsible for setting safety thresholds for environmental pollutants, including asbestos, aiming to the protection and improvement of air quality (United States Environmental Protection Agency, 2021).
Asbestos School Hazard Abatement Reauthorization Act (ASHARA) - 1990
To further financially support the abatement and prevention/reduction of asbestos hazards plans, the EPA furnished the Asbestos School Hazard Abatement Reauthorization Act (ASHARA) that helped, among other things, to extend the funding necessary to cover the costs for realizing these plans (United States Environmental Protection Agency, 2021).
EPA asbestos-related Regulations
Asbestos National Emission Standards for Hazardous Air Pollutants - 1984
The Asbestos National Emission Standards for Hazardous Air Pollutants (NESHAP) is a regulation specifying work practices for demolition and renovation of structures containing asbestos contaminated building materials. Under this regulation, statement of intent needs to be issued to the appropriate agency from the structure’s owner, and certain procedures need to take place to ensure the safe removal and disposal of asbestos contaminated waste. Additionally, any fabrication or manufacturing activity must follow air cleaning processes to avoid visible emission of pollutants (United States Environmental Protection Agency, 2021).
CERCLA Hazardous Substances and Reportable Quantities - 1985
According to the CERCLA Hazardous Substances and Reportable Quantities regulation, asbestos is a hazardous substance, and its quantities need to be measured and reported (United States Environmental Protection Agency, 2021).
Asbestos-Containing Materials in Schools Rule - 1987
The Asbestos-Containing Materials in Schools Rule, stemming from AHERA, is a regulation responsible for having all educational institutions inspect their buildings for asbestos-contaminated materials and have in place plans addressing the prevention and decrease of asbestos hazards (United States Environmental Protection Agency, 2021).
Asbestos Ban and Phaseout Rule - 1989
The EPA had issued the Asbestos Ban and Phaseout Rule in 1989, essentially banning the use of most asbestos-containing products. However, in 1991 the regulation was overturned by the Fifth Circuit Court of Appeals resulting in the distinct reduction of the banned items containing asbestos, but it banned any new items entering the market without proper evaluation and permission (United States Environmental Protection Agency, 2021).
Asbestos Worker Protection Rule - 2000
The EPA Asbestos Worker Protection Rule regulation, under the TSCA, extended the protection required for workers involved in asbestos related activities governed by the OSHA to state and local government employees (United States Environmental Protection Agency, 2021).
Restrictions on Discontinued Uses of Asbestos Rule - 2019
In 2019, the EPA ruled over a total ban of discontinued asbestos contaminated products for uses that were not covered previously in the TSCA, ensuring that in order for asbestos products to get commercialized, would undergo evaluation first. Manufacturers and merchants are required by the law to notify the EPA at least 90 days before the products go onto the market, and are otherwise unable to sell these products until they have received approval from the EPA. In this way, the EPA’s ability to thoroughly review off-market asbestos containing products before they are allowed to get on the market, is strengthened (United States Environmental Protection Agency, 2021; “EPA Actions to Protect the Public,” 2021).
Final Risk Evaluation for Asbestos, Part 1: Chrysotile Asbestos - 2020
In 2020, the EPA finalized the risk evaluation for chrysotile asbestos identifying uses of chrysotile asbestos creating unreasonable health risks and stating the agency’s intent to create a risk management plan for them (“EPA Actions to Protect the Public,” 2021).
Asbestos Abatement
A direct consequence of asbestos-related Laws and Regulations application is the need of special treatment of asbestos contaminated products and building materials in order to isolate and/or neutralize its hazardous nature. This process, called asbestos abatement, is possible with a variety of methods.
Chemical Treatments (1972 – present) (Choi & Smith, 1972 as cited in Spasiano & Pirozzi, 2017)
Chemical treatments of asbestos contaminated materials are based on the principle of dissolution. (Spasiano & Pirozzi, 2017)
Acidic and Aqueous solutions (1972 – present) (Choi & Smith, 1972 as cited in Spasiano & Pirozzi, 2017)
One type of chemical treatment entailing dissolution of asbestos contaminated materials is the use of acidic or saline solutions. In the case of acidic solutions, the mixture is exposed to 100 oC for an entire day resulting to non-hazardous products. Another use of solutions that reduces the asbestos toxicity is the addition of asbestos contaminated materials to saline solutions containing chelating agents letting the mixture at rest for possibly more than a month and at 37 oC. (Spasiano & Pirozzi, 2017)
Carbonization (2004 – present) (Cipolli et al., 2004 as cited in Spasiano & Pirozzi, 2017)
This is a chemical treatment for which asbestos contaminated materials are used for carbon dioxide capturing and storage. Asbestos contaminated materials are pretreated by exposure to heat ranging from 650-700 oC in order to destabilize the asbestos fibers, and then under different pressure and temperature conditions, the asbestos fibers react with dissolved carbon dioxide producing carbonate and magnesium minerals. (Spasiano & Pirozzi, 2017)
Thermal treatments (1981 – present) (Jolicoeur & Duchesne, 1981 as cited in Spasiano & Pirozzi, 2017)
Thermal treatments entail exposure to high temperatures, similar to vitrification. The difference between vitrification and the rest thermal treatments is that for the latter temperatures used can be within the range from 500-1200 oC, depending on both the type of asbestos contaminated material and the type of asbestos itself. Commonly used methods for thermal treatments are by plasma gun use, Joule heating, and conventional ovens. (Spasiano & Pirozzi, 2017)
Solidification and stabilization (1986 – present) (United States Environmental Protection Agency, 1999)
Solidifying and stabilizing materials containing asbestos is an encapsulating technique involving the coating or spraying of the asbestos contaminated material with special compounds able to seal asbestos (Spasiano & Pirozzi, 2017)
Biological Treatments (1992 – present) (Martin et al., 1992 as cited in Spasiano & Pirozzi, 2017)
This is a treatment entailing the involvement of living organisms for asbestos biodegradation purposes. It has been observed microorganisms such fungi, lichens, and bacteria can disrupt asbestos minerals due to their secretion of substances acting as chelating agents. However, when it comes to asbestos contaminated materials such as cement, asbestos fibers remain intact and bonded to the material itself. So, biological treatment for asbestos contaminated material is not yet an option. (Spasiano & Pirozzi, 2017)
Mechanical Treatments (2003 – present) (Plescia et al., 2003 as cited in Spasiano & Pirozzi, 2017)
This type of treatment utilizes chemical physical processes. Different types of mills such as ball, planetary, vibratory, stirring, pin, and rolling, are used to induce physico-chemical transformation due to mechanical energy introduced to the asbestos-contaminated material. The mechanical energy fragmentizes asbestos fibers and the end product is an amorphous non-hazardous material that can be reused for preparation of mortars since its mechanical properties remain as of higher quality in comparison with other building materials. (Spasiano & Pirozzi, 2017)
Vitrification (2008 – present) (Dellisanti et al., 2009 as cited in Spasiano & Pirozzi, 2017)
Vitrification is the process of converting asbestos contaminated material in glass by exposing the material to extreme temperatures ranging from 1200-1600 oC. Creation of the glass is possible because asbestos is comprised of silicate molecules and exposure to heat can alter its structure effectively destroying the hazardous asbestos fibers. (Spasiano & Pirozzi, 2017)
Alternatives
Asbestos was used in different applications because it is heat-resistant, durable, flexible, and a good insulator. As there is no other material offering this combination of properties, its substitution with alternatives has been proven difficult for only one alternative material was good to cover the needs of one property (Lueck, 1982). This is the reason the substitutes used so far are limited, while research for more materials to be found is ongoing.
Materials currently used as asbestos substitutes for certain applications, depending on the application's requirements, are (Australia Wide Removal Encapsulation., 2019; Rayfield, 2020):
Fiberglass for its insulation and heat resistance properties.
Polybenzimidazole (PBI) fiber for fire resistance in personal protective equipment.
Polyurethane foam for insulation.
Wheat, pecan-shell, rice, and other types of flour, as crack and crevice filler in construction.
Cellulose fibers as heat resistant in construction and textile industries.
Amorphous silica fabrics for heat resistant and insulation applications.
Thermoset plastic flours made and liquid and wood or other low-cost flours, used in construction for thermal and noise insulation.
CONCLUSION
Advances on medical research for asbestosis, lung cancer and mesothelioma were critical for connecting the diseases to their source, asbestos, and providing the framework for understanding that the asbestos’ hazardous nature lies on its fibrous structure. Prior to these medical findings, and up until the 1970’s, asbestos consumption was at its highest levels in a world-wide scale.
The rate of asbestos consumption and uses experienced a sharp decline after the 1970’s due to both the legislation set forth by countries around the world, and the people’s realization of asbestos’ hazardous nature to humans.
The legislation pertaining to asbestos’ restricted uses, levels of presence in living environments (commercial, residential), safe removal and waste management are critical for ensuring the safety and quality of life against asbestos related diseases.
The knowledge of asbestos’ toxicity, and its restriction created two main needs: the treatment of asbestos-contaminated products/waste to non-toxic materials (asbestos abatement), and the research for alternative materials to be used as asbestos substitutes. Different types of treatments developed, or currently under investigation, for asbestos abatement provide a solid stepping-stone for safely removing asbestos existing on or within buildings, and materials and wastes that it has been integrated into. Additionally, alternative materials to asbestos are already in the market contributing to the transition from utilizing asbestos to safer and non-hazardous substances.
Based on the references reviewed, the toxic nature of asbestos to humans is indisputable and it should not be used in any application, regardless of how useful and cost-effective it is. However, if asbestos is treated so it loses its toxic component, then it will be safe to use despite having its properties compromised to a certain extend.
For that reason, we find extremely promising the adaptation of treatment of asbestos-contained materials to non-hazardous amorphous materials because it is a method that can be used not only as a waste management technique, but also in the initial stages of asbestos-containing products’ production.
In the waste treatment case, treating asbestos to non-hazardous amorphous materials allows for the reuse and recycle of asbestos byproducts. For the later case, incorporating an in-between stage of asbestos treatment in the production line - preferably right after mining - will allow for the production of asbestos products that are safe to use from the start.
For any properties that the treated asbestos is not able to fulfill, we propose the addition of alternative non-toxic substitutes that will enhance the product’s properties to meet the commercial standards.
Last, but not least, we highly encourage the use of non-toxic and environmentally friendly solutions during chemical treatment for asbestos neutralization.
In conclusion, asbestos in its toxic form should be completely banned and only its non-toxic form should be promoted and allowed for use. And when the later is not possible, either due to costs or asbestos’ preferred properties, alternative materials to substitute for asbestos should be used.
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