Asbestos                by definition is the name of several minerals that 
naturally occur                in the environment as bundles of fibers and are separated into thin                durable threads. Asbestos fibers are resistant to chemicals, fire                & heat and cannot conduct electricity. This is why they are                used in many different industries. Asbestos is divided into 2 subgroups;                1) chrysotile belongs to the serpentine minerals group and has curly                fibers and 2) amphibole straight, needle-like fibers. More on these                subgroups of asbestos is discussed below. Asbestos fibers are known                to be a threat to humans and their lungs because once asbestos fibers                are inhaled into the lungs, they form solid malignant tumors that                can lead to peritoneal, pleural or pericardial mesothelioma. Other                diseases that could develop as a result of exposure to asbestos                include pleural disorders such as asbestosis, pleural thickening,                pleural plaques, and pleural effusions. Scientists discovered this                fact after conducting many studies on patients that had cumulative                asbestos exposures of 5 to 1,200 fiber-year/mL. This metric is common                on patients who have had 40 years of occupational asbestos exposure,                with air concentrations of 0.125 to 30 fiber/mL. Cancerous diseases                from asbestos exposure take many years to develop, as many as 15                years after initial exposure. Smokers who have had occupational                asbestos exposure are at even increased risks of developing lung                cancer. The average time from initial asbestos exposure to development                of mesothelioma lung cancer is 30 years. Family members of workers                who have worked around asbestos in their occupations are also at                risk of developing lung cancer because the husbands carried asbestos                fibers on their clothes while their wives washed them.              
History of Asbestos Use




             Beginning                the late 1800s, asbestos was mined and used in many different industries                all over North America, especially before the World War II. Examples                of industry use include:
             - Automotive industry uses asbestos in vehicle                brakeshoes and clutch pads.
          - Building & construction industry uses asbestos for strengthening                cement as well as sound absorption, roofing, insulation and fireproofing.
          - Shipbuilding industry uses asbestos to insulate hot water pipes,                boilers and steampipes.
          - Asbestos is also used in many different industrial products such                as plastics, ceiling & floor tiles, adhesives, talc-containing                crayons, etc.
             The image on the right is of a ship dismantling site in Alang,                India. This is a site where ships that are over hundred years old                and rusting are destroyed and dismantled. Since these workers dismantle                ships by hand, they are at increased risk of asbestos exposure.                Infact, it is estimated that 1 out of 6 workers on this worksite                are suffering from Asbestosis or other asbestos related diseases.              
             
Asbestos                was banned from use near gas fireplaces and wallboard patching compounds                by the U.S. Consumer Product Safety Commission (CPSC) in the early                1980s. In 1989, the U.S. Environmental Protection Agency (EPA) banned                all new uses of Asbestos and required all schools to inspect their                building compounds for presence of asbestos fibers and ordered immediate                asbestos abatement. In August 2000, the EPA ordered an investigation                inquiry into the use of vermiculite asbestos in gardening products.                The study concluded that vermiculite asbestos posed minimal health                risks and the EPA advised gardening consumers to minimize emission                of dust whilst gardening. The EPA also suggested consumers use vermiculite                in well ventilated areas only and keep it damp. It was also suggested                to use premixed potting soil which is less likely to emit dust.                In June 2000, the EPA determined that asbestos fibers that reside                in crayons & pencils did not pose a health risk to children                using them, although crayon manufacturers agreed to eliminate the                use of talc in their products. According to Cancer.Gov, the use                of asbestos in the US has decline from 803,000 metric tons in 1973                to only 2,400 metric tons in 2005. 
             
Health Hazards & Risks of Asbestos                Exposure

             Most                mesothelioma lung cancer patients have been exposed to asbestos                whilst at work, whether they are at metal works, construction sites,                shipyards, automotive or plastics industries. If products containing                asbestos are disturbed, tiny asbestos fibers are released into the                air. If these fibers are inhaled by humans, they get trapped in                the lungs and can work their way into the pleura thus causing pleural                mesothelioma, or into the pericardial cavity causing pericardial                mesothelioma or into the abdomen (linings of the lungs) causing                peritoneal mesothelioma. These fibers can accumulate in the lungs                over a long period of time and cause serious inflammation leading                to shortness of breath & excessive cough (which are the first                symptoms of mesothelioma lung cancer). Asbestos has officially been                classified as a human carcinogen (a substance that causes lung cancer)                by the EPA and the U.S. Department of Health and Human Services.                Asbestos exposure can also cause Asbestosis which is a chronic lung                disease that results in symptoms such as excessive cough, shortness                of breath & permanent lung damages. 
             The                risks for asbestos exposure are not high for everyday people who                are exposed to the air, water and the soil of the earth. It is occupational                asbestos workers that come into contact with asbestos products on                a daily basis that are at high risk of inhaling asbestos fibers.                Starting from the 1940s (before World War II) and onwards, millions                of American workers have been exposed to Asbestos on the job. These                types of jobs include firefighters, automobile workers, drywall                removers, demolition workers, insulation workers in the construction                & building industry, as well as mining & shipbuilding workers.                Other workers involved in the cleanup of the September 11th, 2001                terrorist attacks on the World Trade Center (WTC) in New York City                are also at risk. How were asbestos fibers released into the air                during the attacks? Asbestos was used in the construction of the                North Tower of the World Trade Center and when this building was                blown up, hundreds of tons of asbestos fibers were released into                the air. On the job workers who are at most risk include firefighters,                paramedics, construction workers & volunteers, police officers                & investigators. 70% of workers who helped in the rescue and                clean up efforts of the September 11th, 2001 attacks suffered worse                respiratory systems and 28% had abnormal lung function tests. 
             
Factors that Affect Risk of Developing Asbestos Related Diseases
             There are several factors that determine the risk of asbestos workers                developing asbestos related diseases. They include:
             i) Dose (amount of asbestos the worker was exposed to).
          ii) Duration (how long the worker was exposed to asbestos)
          iii) Chemical properties, size & shape of asbestos fibers
          iv) Source of exposure, e.g the blowup of the North tower of the                World Trade Center that released hundreds of tons of asbestos fibers                into the air
          v) Other risk factors including smoking and prior lung diseases
             
Symptoms of Asbestos Related Diseases
             So how do patients know they have developed an asbestos related                disease such as mesothelioma lung cancer? By the symptoms, here                they are:
             - Fatigue or anemia
          - Loss of appetite
          - Weight loss
          - Difficulty swallowing
          - Swelling of the face or neck
          - Blood coughed up from the lungs
          - Excessive cough
          - Hoarseness or shortness of breath
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