Asbestos Exposure & Mesothelioma - What is Asbestos, History, Usage, Health Hazards & Risks, Asbestos Related Diseases

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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