Asbestos is a set of six naturally occurring silicate minerals, all of which share the same eponymous asbestiform habit: the length (approx 1:20 aspect ratio), thin fibrous crystals, with each visible fiber composed of millions microscopic "fibrils" that can be released by abrasion and other processes. They are commonly known for their colors, such as blue asbestos, brown asbestos, white asbestos, and green asbestos.
Asbestos mining existed more than 4,000 years ago, but large-scale mining began in the late 19th century, when producers and builders began using asbestos for their desirable physical properties. Some of these properties are sound absorption, average tensile strength, affordability, and resistance to fire, heat, and electricity. It is used in applications such as electrical insulation for hotplate cables and in building insulation. When asbestos is used for its resistance to fire or heat, the fiber is often mixed with cement or woven into a cloth or mat. This desirable property makes asbestos very widely used. The use of asbestos continues to grow through most of the 20th century until public knowledge (acting through courts and legislatures) from the health hazards of asbestos dust bans asbestos in mainstream and fireproof construction in most countries.
Inhaling asbestos fibers can cause serious and fatal diseases including lung cancer, mesothelioma, and asbestosis (a type of pneumoconiosis). The concerns of asbestos-related diseases in modern times began in the 20th century and increased during the 1920s and 1930s. In the 1980s and 1990s, trade and use of asbestos was severely restricted, removed, or banned in some countries.
Despite the severity of asbestos-related diseases, these materials have been widely used in many areas. Continuing long-term use of asbestos after harmful health effects is known or suspected, and the slow pace of symptoms several decades after exposure to stops, makes asbestos litigation the longest and most expensive mass lawsuit in US history and much lower legal matters in most other countries. involved. Asbestos related liabilities also remain an ongoing concern for many manufacturers, insurance and reinsurance companies.
Video Asbestos
Etymology
Asbestos comes from the ancient Greek ????????, which means "unquenchable" or "indistinguishable". Words uttered , or .
Maps Asbestos
Related types and fibers
Six types of minerals are defined by the United States Environmental Protection Agency (EPA) as "asbestos" including those belonging to the serpentine class and which belong to the amphibole class. All six types of asbestos minerals are known as human carcinogens. The visible fibers themselves each consist of millions of microscopic "fibrils" that can be released by abrasion and other processes.
Serpentine
Serpentine class fibers are curly in shape. Chrysotile is the only member of the serpentine class.
Chrysotile
Chrysotile, CAS No. 12001-29-5, obtained from common serpentinite rocks throughout the world. The ideal chemical formula is Mg 3 (Si 2 O 5 ) (OH) 4 . Chrysotile appears under a microscope as a white fiber.
Chrysotile has been used more than other types and accounts for about 95% of the asbestos found in buildings in America. Chrysotile is more flexible than the type of asbestos amphibians, and can be spun and woven into fabric. The most common use is the corrugated asbestos roof especially for outbuildings, warehouses and garages. These can also be found in sheets or panels used for ceilings and sometimes for walls and floors. Chrysotile has become a component in the combined compound and some plaster. Many other items have been made containing chrysotile including brake lining, fire barrier in fusebox, pipe insulation, floor tiles, shingle housing, and gaskets for high temperature equipment.
Amphibole
Amphibole class fiber resembles a needle. Amosite, crocidolite, tremolite, anthophyllite and actinolite are members of the amphibole class.
Amosite
Amosite, CAS No. 12172-73-5, commonly referred to as chocolate asbestos, is a trade name for amphiboles belonging to the cummingtonite-grunerite solid solution series, generally from South Africa, named as partial abbreviation for "Asbestos Mines of South Africa". One formula given for amosite is Fe 7 Si 8 O 22 (OH) 2 . Amosite is seen under a microscope as a white gray vitreous fiber. It is found most often as a fire retardant in thermal insulation products, asbestos insulation boards and ceiling tiles.
Crocidolite
Crocidolite, CAS No. 12001-28-4, is a fibrous form of amphibole riebeckit, found mainly in southern Africa, but also in Australia and Bolivia. One formula given for crocidolite is Na 2 Fe 2 3 Fe 3 2 Si 8 O 22 (OH) 2 . Crocidolite is seen under a microscope as a blue fiber.
Crocidolite generally occurs as soft loose fibers. Asbestiform amphibole can also occur as soft fibers loose but some varieties such as amosite are generally more straight. All forms of asbestos are fibrillar because they consist of fibers less than 1 micrometer wide in bundles of very large widths. Asbestos with very fine fibers are also referred to as "amianthus".
Other materials
Other regulated asbestos minerals, such as tremolite asbestos, CAS No. (OH) 2 /sub>; actinolite asbestos, CAS No. 77536-66-4, Ca 2 (Si 8 O 22 ) (OH ) 2 ; and anthropic asbestos, CAS No. 77536-67-5, (Mg, Fe) 7 Si 8 22 (OH) 2 ; less often used industrially but can still be found in a variety of construction materials and insulating materials and has been used in some consumer products.
Other natural asbestiform minerals, such as richterite, Na (CaNa) (Mg, Fe ) 5 (Si 8 O 22 (Al, Fe 3 ) (Si 8 ), and winchite, (CaNa) Mg 4 sub> O 22 ) (OH) 2 , although not set, is said by some to be no less dangerous than tremolite, amosite, or crocidolite. They are called "asbestiform" rather than asbestos. Although the US Occupational Safety and Health Administration (OSHA) has not included them in asbestos standards, NIOSH and the American Thoracic Society have recommended them to be included as regulated materials as they can also be harmful to health.
Production
In 2009, about 9% of world asbestos production was mined in Canada. By the end of 2011, two remaining Canadian asbestos mines, both located in Quebec, suspended operations. In September 2012, the Quebec government stopped asbestos mining.
By 2015, 2 million tons of asbestos are mined worldwide. The Russian Federation is the largest producer with about 55% of the world's share followed by China (20%), Brazil (15.6%), and Kazakhstan (10.8%).
History of use
Initial use
The use of asbestos dates back at least 4,500 years, when residents of Lake JuojÃÆ'¤rvi region in Eastern Finland reinforced pottery pots and cooking utensils with mineral asbestos anthophyllite (see Asbestos-ceramics). One of the first descriptions of asbestos possible material is in Theophrastus, On Stones , from about 300 BC, although this identification has been questioned. In both modern and ancient Greek, the usual name for the material known in English as "asbestos" is amiantos ("unpolluted", "pure"), adapted into French > amiante and Portuguese amianto . In modern Greek, the word ???????? or ???????? standing consistently and only for lime.
The term asbestos can be traced to the Roman naturalist text of Pliny the Elder Natural History, and its use of the term asbestinon, meaning "unquenchable". While Pliny or his nephew, Pliny the Younger, is popularly credited with recognizing the detrimental effect of asbestos on humans, the examination of primary sources shows no support for claims.
The rich Persian made the guests awe by cleaning the cloth by exposing it to the fire. For example, according to Tabari, one of the curiosities of Khosrow II Parviz, the great king of Sassania (r. 531-579), was a napkin (Persia: span lang = "fa" dir = "rtl">? ???? ?) which he clears by simply throwing it into the fire. Such fabrics are believed to be made of asbestos imported over Hindu Kush. According to Biruni in his book, Permata , any fabric made of asbestos (Persian: ?????? ?, ? zarshost ) is called shostakeh (Persian: ????? ? ). Some Persians believe that the fibers are animal hair, called samandar (Persian: span lang = "fa" dir = "rtl"> ????? ?), Which is alive in fire and dead when exposed to water, which is the former belief that a salamander can tolerate fire originating.
Charlemagne, the first Holy Roman Emperor (800-814), is said to have a tablecloth made of asbestos.
Marco Polo recounted that it was shown, in the place he called the Ghinghin taiji, a nice vein from which the cloth we call salamander, which can not be burned if thrown into the fire, made... "
Some archaeologists believe that the ancients made the asbestos shroud, where they burned the bodies of their kings, to just defend their ashes, and prevent them mixed with wood or other combustible materials commonly used in firewood burial. Others assert that the ancients used asbestos to create an eternal axis for sepulchral lights or other lights. A notable example is the gold lamp asbestos lychnis , which the sculptor Callimachus made for Erechtheion. In newer centuries, asbestos is indeed used for this purpose. Although asbestos causes itchy skin during contact, ancient literature suggests that it is prescribed for skin diseases, and especially for itching. It is possible that they use the term asbestos for soapstone, since the two terms are often confusing throughout history.
Industrial era
Large scale asbestos industry began in the mid-19th century. Early attempts to produce asbestos paper and cloth in Italy began in the 1850s, but were unsuccessful in creating a market for these products. Canadian asbestos samples were displayed in London in 1862, and the first companies were formed in England and Scotland to exploit these resources. Asbestos was first used in the manufacture of yarn, and German industrialist Louis Wertheim adopted this process at his factory in Germany. In 1871, the Patent Asbestos Manufacturing Company was established in Glasgow, and within the next few decades, the Clydebank area became the center of the nascent industry.
Industrial scale mining began in the hills of Thetford, Quebec from the 1870s. Sir William Edmond Logan was the first to notice the huge chrysotile deposits in the hills in his capacity as head of the Canadian Geological Survey. The mineral samples from here are on display in London, and are very interested. With the opening of the Quebec Central Railway in 1876, mining entrepreneurs, such as Andrew Stuart Johnson founded the asbestos industry in the province. The output of 50 tonnes of mines in 1878 rose to over 10,000 tons in the 1890s with the adoption of machine technology and production expansion. For a long time, the world's largest asbestos mine was the Jeffrey mine in the city of Asbestos, Quebec.
Asbestos production began in the Imperial Ural of Russia in the 1880s, and in the Alps of northern Italy with the formation in Turin of the Italo-British Pure Asbestos Company in 1876, although this was soon overrun by a larger production rate of the Canadian Mine. Mining also began in South Africa from 1893 under the supervision of British businessman Francis Oates, Director of the company De Beers. It was in South Africa that the production of amosite began in 1910. The US asbestos industry had an earlier start in 1858, when fibrous anthophyllite was mined for use as asbestos insulation by the Johns Company, the predecessor to present Johns Manville, in quarry at Ward's Hill in Staten Island, New York. US production began in 1899, with the discovery of a large deposit in Belvidere Mountain.
The use of asbestos became increasingly widespread towards the end of the 19th century, when diverse applications included refractory, concrete, brick, pipe and cement fireplace, heat, fire, and acid-resistant gaskets, pipe insulation, ceiling insulation, refractory drywall , floors, roofs, lawn furniture, and compound drywall joints. In 2011 it was reported that more than 50% of homes in Britain still contain asbestos, despite the prohibition of asbestos products several years earlier.
In Japan, especially after World War II, asbestos was used in the manufacture of ammonium sulfate for the purposes of rice production, sprayed onto the ceiling, steel frame, and railway and building car walls (during the 1960s), and used for energy efficiency. reason too. Asbestos production in Japan peaked in 1974 and experienced ups and downs until around 1990, when production began to drop dramatically.
Discovery toxicity
In 1899, Montague Murray noted the negative health effects of asbestos. The first documented death associated with asbestos was in 1906.
In the early 1900s researchers began to notice a large number of early deaths and lung problems in asbestos mining towns. The first such study was conducted by H. Montague Murray at Charing Cross Hospital, London, in 1900, where postmortem investigation of a young man who died from pulmonary fibrosis after working for 14 years in the asbestos textile factory, found traces of asbestos in the lungs victim. Adelaide Anderson, Factory Inspector in England, put asbestos into the list of hazardous industrial substances in 1902. Similar investigations were conducted in France and Italy, respectively in 1906 and 1908.
The first diagnosis of asbestosis was made in England in 1924. Nellie Kershaw was employed at Turner Brothers Asbestos in Manchester, England from 1917, spun raw asbestos fibers into yarns. His death in 1924 led to an official examination. The pathologist William Edmund Cooke testified that his lung examination indicated an old scar indicating previous tuberculosis infection, healed, and extensive fibrosis, in which "mineral particles particles... of various forms, but most have angles." After comparing these particles with asbestos dust samples provided by SA Henry, His Factory Medical Inspector, Cooke concluded that they were "of asbestos and, beyond any reasonable doubt, the main cause of pulmonary fibrosis and hence death.".
As a result of Cooke's paper, the parliament commissioned an investigation into the effects of asbestos dust by E. R. A. Merewether, Factory Medical Inspector, and C. W. Price , factory inspector and pioneer of dust monitoring and control. Their next report, Occurrence of Lung Fibrosis & amp; Other Lung Suffering at Asbestos Workers, presented to parliament on March 24, 1930. It was concluded that the development of asbestosis is undeniably related to inhalation of prolonged asbestos, and includes the first health research of asbestos workers, who found that 66% of those employed for 20 years or more suffering from asbestosis. The report led to the issuance of the first Asbestos Industrial Regulation in 1931, which came into force on 1 March 1932. This regulated ventilation and make asbestosis an acceptable occupational illness. The term mesothelioma was first used in medical literature in 1931; his association with asbestos was first noted in the 1940s. Similar laws followed in the US about ten years later.
About 100,000 people in the United States have died, or are seriously ill, from asbestos exposure associated with shipbuilding. In the Hampton Roads area, the shipbuilding center, the incidence of mesothelioma is seven times the national level. Thousands of tons of asbestos were used in World War II ships to isolate pipes, boilers, steam engines, and steam turbines. There were about 4.3 million shipyard workers in the United States during World War II; for every 1,000 workers about 14 died from mesothelioma and an unknown number died of asbestosis.
The United States government and the asbestos industry have been criticized for not acting quickly enough to inform the public of the dangers, and to reduce public exposure. In the late 1970s, court documents proved that asbestos industry officials knew the dangers of asbestos since the 1930s and hid it from the public.
In Australia, asbestos was widely used in construction and other industries between 1946 and 1980. From the 1970s there was increasing concern about the dangers of asbestos, and its use was phased out. Mining stopped in 1983. The use of asbestos was removed in 1989 and banned entirely in December 2003. Asbestos hazards are now known in Australia and there is help and support for asbestosis or mesothelioma sufferers.
Industrial based usage and product type
Serpentine Group
Serpentine minerals have sheets or layered structures. Chrysotile is the only mineral asbestos in the serpentine group. In the United States, chrysotile is the most commonly used type of asbestos. According to Asbestos Building Inspector Manual US EPA, chrysotile accounts for about 95% of asbestos found in buildings in the United States. Chrysotile is often present in a wide range of products and materials, including:
- Chlor Alkali membrane diaphragm is used to make chlorine (currently in the USA)
- Compounds of drywall and joints (including texture layers)
- Plaster
- Pre-1960 gas filter filter and gas mask filter from USSR
- Vinyl floor tiles, tarpaulins, glue
- Roof ter, felt, wall, and shingles
- "Transite" panels, coatings, countertops, and pipes
- Popcorn ceilings, also known as acoustic ceilings
- Fireproofing
- Caulk
- Industrial and marine gaskets
- Brake pads and shoes
- Stage curtain
- Fire blanket
- The interior fire door
- Fireproof clothing for firefighters
- Thermal pipe insulation
- Filter to remove fine particles from chemicals, liquids, and grapes
- Gypsum plaster
- HVAC flexible channel connector
- Drinking fluid additives
In the EU and Australia it has been banned as a potential health hazard and not used at all. Japan is moving in the same direction, but at a slower pace.
Amphibole Group
Amphibol including amosite (brown asbestos) and crocidolite (blue asbestos) were previously used in many products until the early 1980s. Asbestos tremolite is a contaminant of many if not all natural chrysotile deposits. The use of all types of asbestos in the amphibole group was banned in much of the Western world in the mid-1980s, and in Japan in 1995. Some products that include amphibole types of asbestos include the following:
- Low-density insulation board (often referred to as AIB or asbestos insulation board) and ceiling tiles;
- Asbestos-cement pipes (made until the early 1990s by at least one manufacturer);
- Asbestos-cement sheets and pipes for construction, casing for water and electricity/telecommunication services;
- Thermal and chemical insulation (eg doors with fire ratings, limpet spray, lagging, and gaskets).
The Lorillard cigarette factory (filtered cigarette Kent) used crocidolite asbestos in a "Micronite" filter from 1952 to 1956.
While most of the chrysotile asbestos fibers were once used in automobile brake pads, shoes, and clutch discs, amphiboles contaminants are present. Since around the mid-1990s, brake pads, new or replacements, have been produced instead of coatings made of ceramic, carbon, metallic and aramid fibers (Twaron or Kevlar - the same material used in bulletproof vests).
Artificial Christmas snow, known as flocking, was previously made with asbestos. It is used as an effect in movies including The Wizard of Oz and display window department stores and is marketed for use in private homes with brand names including "Pure White", "Snow Drift" and "White Magic".
Construction
Developed countries
The use of asbestos in new construction projects has been banned for health and safety reasons in many developed countries or regions, including the European Union, Australia, Hong Kong, Japan and New Zealand. An important exception is the United States, where asbestos continues to be used in construction such as asbestos pipe of cement. The 5th Circuit Court prevented the EPA from banning asbestos in 1991 because the EPA study showed a ban would cost between $ 450 and 800 million while only saving about 200 people within 13 years, and that the EPA did not provide sufficient evidence for product safety alternative. (The summary of this case is misleading and misleading the law.Lack of discussing alternative products and costing only two factors of dozens and dozens of deficiencies in the proposed EPA of regulatory legislation.EPA even made procedural errors, for example obstructing cross-examination of witnesses for the EPA, in violation of TCSA, decided against the EPA for failing to provide sufficient evidence to justify the ban - cost estimates are just one factor out of many.His next, the Court ruled the establishment of a regulation for the EPA due to a lack of substantial evidence.Packing is not the same as "preventing the EPA from banning asbestos." It looks like this summary is written by someone without legal knowledge who only scans Court opinion and chooses a cheerful sensational language.Also note, the EPA's estimate of 200 deaths does not take into account the predicted deaths of alternative products, such as PVC pipes, which can exceed deaths from asbestos pipelines). Until the mid-1980s, a small number of white asbestos were used in Artex making, decorative finishing, however, some of the lesser-known Artex suppliers still added white asbestos until 1999.
Before the ban, asbestos was widely used in the construction industry in thousands of materials. Some are judged to be more dangerous than others due to the number of asbestos and fragile material properties. Spraying coatings, pipe insulation and Asbestos Insulating Board (AIB) are considered to be the most dangerous because of their high asbestos and friable content. Many old buildings built before the late 1990s contain asbestos. In the United States, there are minimum standards for asbestos surveys as described by ASTM Standard E 2356-04. In the UK, the Health and Safety Executive has issued a guide called HSG264 that explains how the survey should be completed even if other methods can be used if they can demonstrate that they have met the rules in other ways. U.S. Environmental Protection Agency includes some but not all asbestos contaminated facilities on the Superfund National Priorities (NPL) list. Renovation and destruction of asbestos contaminated buildings are subject to EPA Regulations NESHAP and OSHA. Asbestos is not a material covered by the defense of CERCLA's innocent buyer. In the UK, the removal and disposal of asbestos and its constituents is protected by Asbestos Regulations 2006 Control.
US asbestos consumption reached a peak of 804,000 tons in 1973; world asbestos demand reached its peak around 1977, with 25 countries producing nearly 4.8 million metric tons per year.
In old buildings (eg built before 1999 in Britain, before white asbestos is banned), asbestos may still exist in some areas. Realizing the location of asbestos reduces the risk of disrupting asbestos.
The removal of asbestos building components may also remove the fire protection they provide, therefore a replacement for fire protection is required for proper fire protection that asbestos is initially provided.
Outside Europe and North America
Some countries, such as India, Indonesia, China, Russia and Brazil, continue to use asbestos extensively. The most common are asbestos-cement corrugated sheets or "A/C sheets" for the roof and for side walls. Millions of homes, factories, schools or warehouses and shelters continue to use asbestos. Cut this sheet to fit the size and drill a hole to receive the 'J' bolt to help secure the sheet to the roof frame in place. There has been no significant change in the production and use of A/C sheets in developing countries after widespread restrictions in developed countries. "The largest exporter of asbestos is Russia, which exports 100 million metric tons of asbestos, which is shipped to countries that still use cheap and effective building materials.China is the number one importer of asbestos, using more than five hundred and seventy metric tons of harmful substances in 2013 alone. China is not the only country that uses asbestos, Russia, Canada, Brazil and India all use asbestos. "
September 11, 2001 attack
When the World Trade Center in New York City collapsed after the September 11 attacks, Lower Manhattan was covered by a mixture of building debris and combustible materials. This complex mixture raises concerns that thousands of residents and workers in the area will be exposed to known dangers in the air and in dust, such as asbestos, lead, glass fibers, and crushed concrete. More than 1,000 tonnes of asbestos are thought to have been released into the air after the destruction of buildings. Inhaling mixtures of asbestos and other toxins is thought to be associated with an unusually high mortality rate from cancer service emergency workers since the disaster. Thousands more are now considered at risk of developing cancer because this exposure to those who have died so far only became "the tip of the iceberg". Some commentators have criticized authorities for using asbestos in building construction.
In May 2002, after numerous cleanup, dust collection and air monitoring activities were conducted outdoors by EPA, other federal agencies, New York City, and New York state, New York City formally requested federal assistance to clean and test the premises living around the World Trade Center site for air asbestos.
Asbestos contaminants in other products
Vermiculite
Vermiculite is a hydrated magnesium-aluminum-iron hydrate silicate that resembles mica. It can be used for many industrial applications and has been used as isolation. Several vermiculite deposits have been found to be contaminated with small amounts of asbestos.
One vermiculite mine operated by W. R. Grace and Company in Libby, Montana exposes workers and citizens to hazards by mining vermiculite contaminated with asbestos, usually richterite, winchite, actinolite or tremolite. Vermiculite contaminated with asbestos from the Libby mine is used as insulation in residential and commercial buildings through Canada and the United States. W. R. Grace and the Company's Free Vermiculite are marketed as Zonolites but are also used in sprayed products such as Monokote.
In 1999 the EPA started cleaning efforts in Libby and now this area is a Superfund cleaning area. The EPA has determined that dangerous asbestos is released from the mine as well as through other activities that disrupt the soil in the area.
Talc
Talc can sometimes be contaminated with asbestos due to the proximity of the orbestos (usually tremolite) in the underground talc deposits. In 1973, the US federal law required all powder products to be free of asbestos, and today there is strict quality control in the production of talc products, separating cosmetic grade powders (eg talcum powder) from industrial grade talc (often used in friction products) has eliminated most of these problems for consumers.
In 2000, the test in a certified asbestos testing laboratory found the amphibole asbestos tremolit form used to be found in three of the eight popular children's crayon brands made part of the talc: Crayola, Prang, and RoseArt. At Crayola crayon, the test found an asbestos level of about 0.05% at Carnation Pink and 2.86% at Orchid ; in Crayon Prang, the range from 0.3% in Periwinkle to 0.54% in Yellow ; on Rose Art crayons, it's from 0.03% at Brown to 1.20% at Orange . Overall, 32 types of crayons from this brand are used to contain more than asbestos traces, and the other eight contain trace amounts. The Art and Creative Materials Institute, a trade association that tests the safety of crayons on behalf of the makers, initially insisted that the test results were inevitably wrong, even though they later said they were not testing asbestos. In May 2000, Crayola said the test by Richard Lee, a material analyst whose testimony on behalf of the asbestos industry had been accepted in lawsuits more than 250 times, found his crayon tested negative for asbestos. Regardless, in June 2000 Binney & amp; Smith, Crayola makers, and other makers agreed to stop using powder in their products, and change their product formulations in the United States.
The mining company, R T Vanderbilt Co of Gouverneur, New York, which supplies talc to crayon makers, stated that "as far as we know and believe" there is no asbestos in the difference. But media reports claim that the US Mine Safety and Health Administration (MSHA) has discovered asbestos in four samples of talcas tested in 2000. Assistant Secretary of Mine Safety and Health later wrote to a news reporter, stating that "In fact, the abbreviation ND (undetectable ) in laboratory reports - showing no asbestos fiber actually found in the sample ", and some studies by mineral research laboratories and biological cell studies do not report asbestos. These findings have been rejected by other health reports and studies that advocate risk "just as" asbestos.
Health impact
All types of asbestos fibers are known to cause serious health hazards in humans. Amosite and crocidolite are considered the most dangerous types of asbestos fibers; However, chrysotile asbestos has also produced tumors in animals and is a recognized cause of asbestosis and malignant mesothelioma in humans, and mesothelioma has been observed in people whose occupations are exposed to chrysotile, family members employed in the workplace, and residents living close to asbestos and mine factories.
During the 1980s and again in the 1990s, it was sometimes suggested that the process of making asbestos cement could "neutralize" asbestos, either through chemical processes or by causing cement to stick to fibers and alter their physical size; subsequent research shows that this is not true, and that asbestos cement is decades old, when it breaks down, releasing asbestos fibers identical to those found in nature, with no detectable changes.
Exposure to asbestos in the form of fiber is always considered dangerous. Working with, or exposed to, fragile materials, or materials or works that may cause release of loose asbestos fibers, is considered to be high risk. In general, people who become ill from inhaling asbestos have been regularly exposed in jobs where they work directly with the material.
The most common diseases associated with chronic exposure to asbestos are asbestosis and mesothelioma.
Substitutes for asbestos under construction
Fiberglass insulation was invented in 1938 and is now the most commonly used insulation type. The safety of this material is also questionable because of the similarity in the material structure. However, the International Agency for Research on Cancer removed fiberglass from a list of possible human carcinogens in 2001 and a review article from 2011 states epidemiological data is inconsistent and concludes that the IARC decision to decrease the carcinogenic potential of fiberglass is valid (however, the study is funded by a research contract sponsored by the North American Insulation Manufacturers Association).
In 1978, a high-textured fiberglass cloth was created by Bal Dixit, called Zetex. This fabric is lighter than asbestos, but offers the same mass resistance, thickness, hand, taste, and abrasion as asbestos. Fiberglass is textured to eliminate some of the problems that arise with fiberglass, such as poor abrasion resistance and poor stitching strength.
In Europe, mineral wool and glass wool are the main insulators in homes.
Many companies that produce asbestos cement products reinforced with asbestos fibers have developed products that combine organic fiber. One such product is known as "Plasterboard" and the other "Everite" now uses "Nutec" fiber which consists of organic fiber, portland cement and silica. The cemented wood fiber cement is another substitute. Stone fibers are used in gasket and friction material.
Other potential fibers are polybenzimidazole or PBI fibers. Polybenzimidazole fibers are synthetic fibers with a high melting point of 760 ° C (1,400 ° F) which is also not lit. Due to its exceptional thermal and chemical stability, it is often used by fire departments and space agencies.
Recycling and disposal
Asbestos alternative for industrial use including sleeve, strap, tape, fabric, textile and insulating batt material made of fiberglass and silica.
In most developed countries, asbestos is usually disposed of as hazardous waste in landfill sites.
Demolition of buildings containing large amounts of asbestos-based materials poses particular problems for builders and property developers - such buildings often have to be deconstructed piece by piece, or asbestos must be thrown away before the structure can be undermined by mechanical or explosive means.. One example is the Red Road Flats in Glasgow, Scotland that use large asbestos cement boards for wall panels - here British health and safety regulations stipulate that asbestos materials should be disposed to the landfill site via approved routes at certain times. day in a customized custom vehicle.
In the United States, the EPA regulates the elimination and disposal of asbestos strictly. Companies that remove asbestos must comply with the EPA license. These companies are called EPA licensed asbestos contractors. Whenever one of these asbestos contractors does the work, a test consultant must perform rigorous testing to make sure asbestos is completely removed.
Asbestos can be recycled by converting it into harmless silicate glass. The thermal decomposition process at 1000-1250 ° C produces a harmless mixture of silicate phases, and at temperatures above 1250 ° C produces silicate glass. The microwave heat treatment can be used in industrial manufacturing processes to transform asbestos and asbestos waste containing to porcelain stoneware tiles, porous porous porous tiles, and ceramic bricks.
The combination of oxalic acid with ultrasound completely decreases chrysotile asbestos fibers.
See also
- Asbestine
- Mineral list
- Asbestos abatement
- Asbestos and law
- Asbestos Disease Awareness Organization
- Asbestos-ceramic
- Asbestos cement
- Medical geology
- Red List of building materials
References
Bibliography
- Castleman, Barry I. (1996). Asbestos: Medical and Legal Aspects . Englewood Cliffs, NJ: Aspen Publisher. ISBN 978-0-7355-5260-9.
Further reading
- George B. Guthrie and Brooke T. Mossman, editor, Mineral Dust Effects , American Mineralogy Society Reviews in Mineralogy v. 28, 584 pages (1993) ISBNÃ, 0-939950-33-2.
- The major mortality and morbidity of Asbestos-related diseases in Asia tends to increase over the next 20 years
- Asbestos: introduction by JW Cherrie
- Tweedale, Geoffrey (2000). Magic Minerals for Turner & Dust Killer Newall and Asbestos Hazard . Oxford Univ. Press. p.Ã, 336. ISBNÃ, 978-0-19-829690-4.
External links
- Asbestos Disease Awareness Organization
- Independent Asbestos Information Center website with information on asbestos and its use in buildings
- US. Home page of EPA Asbestos
- Case Study of ATSDR in Environmental Medicine: Asbestos Poisoning Department of Health and Human Services of the USA
- UK Government Health and Safety (HSE) Executive
- National Institute for Occupational Safety and Health: Asbestos
- World Health Organization - Asbestos page
- General articles of asbestos and chrysotile specifically: comprehensive coverage of all aspects of chemistry, biological interactions, vandalism, and social/clinical scientific knowledge associated with Asbestos, on Toxicology Data Networks, with complete libraries citing various aspects and sub-topics].
- Parachrysotile (asbestos) in webmineral.com Mineral Database
- Univ. from Minn.: Asbestos
- White Gold Pioneers: Asbestos Mining - Origin of asbestos mining, illustrated with many early photographs
- How to Identify Asbestos - Independent site cites how to identify early signs of Asbestos and actions to take
Source of the article : Wikipedia
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