Asbestos. Over thirty million people have been exposed to asbestos in the past forty-two years. It

Transcription

1 Asbestos Lauren McCarthy 4/12/10 Section G Red Over thirty million people have been exposed to asbestos in the past forty-two years. It was one hundred years ago that a naturally occurring mineral silicate called asbestos was first commercially manufactured in England. These fire resistant crystalline fibers come in the form of six minerals and their central usage was as a fire retardant. However, its usage did not last long because it was discovered to have extreme effects on the respiratory system of workers. Asbestos, a miracle mineral once thought to hold the hope for the future, left devastating results after being produced in hundreds of products during the 20 th century. Chemical Properties Asbestos is a group of six specific naturally occurring fibrous silicate minerals. These six solid flexible fibours are divided into two groups, serpentine and amphibole. The Amphibole group contains the minerals crocidolite, tremolite, actinolite, and anthophyllite; the last mineral belonging to the serpentine group is chrysotile. Chrysotile, Mg 6 (Si 4 O 10 )(OH) 8, is the most common fiber; however, all of these minerals share common chemical traits ("Asbestos," 1996, para. 1). They are all heat resistant, do not evaporate in air or dissolve in water, have no odor and do not migrate through the soil. The serpentine fiber, chrysotile sets itself apart from the amphibole group because it is insoluble in acid. Besides being inert, asbestos has a range of physical properties that make it appealing to industrial chemistry. Its tensile strength is half of that of steel yet it is remarkably flexible, enough so that it may be added to clothing. It is ideal for construction purposes not only for its thermal and electrical resistance, but also for its

2 electrical insulating capabilities. The color varies depending on the type. Although these six minerals may appear to be the same, they each have unique differences. The amphiboles, also called inosilicates have double chains with basic structural units being Si 4 O 11 ("Asbestos," 1996, para 4). Within this group, the types vary by amount and positioning of metal atoms such as sodium, calcium, manganese, magnesium, iron(ii), iron(iii), and aluminum. Comparatively, serpentine differs from the five other forms included in the amphibole group. Chysotile is much less friable, meaning the ability to turn into dust with finger pressure. Because all forms of asbestos have unusual traits, they were used in many products during the 20 th century. Figure 1. These microscopic asbestos fibers appear to be the perfect addition to any product; however, they do more harm than help ("How to purify," 2010). Uses Because of its diverse capabilities, asbestos appealed to many manufacturing companies. The most common usage was in building materials. The toxin s fire-resistant and sound-

3 absorbing capabilities along with its strong yet flexible fiber structure made it ideal for roofing shingles, ceiling and floor tiles, paper products, insulation, and paint (Ciullo, 1996). Additionally, it was popular in the automotive industry because it does not conduct electricity making it useful for friction products such as the automotive clutch, brake, and transmission. It was even woven into clothes and has even been found in vermiculite garden products and talccontaining crayons ("Asbestos exposure and," 2009, pg. 1). However, its usage increased during World War II when it was used for fireproofing naval ships and airplanes. Once asbestos became widely used, diseases arose. Asbestosis Asbestosis, a respiratory disease, is caused by the inhalation of asbestos fibers. The symptoms of this irreversible disease are coughing, chest pain, tightness in the chest and shortness of breath. The disease develops when build up of asbestos fibers in the lungs cause scar tissue. This scar tissue cannot expand and contract normally; therefore, it cannot absorb the correct amounts of oxygen. The severity of the disease depends on length of exposure and amount inhaled. Unfortunately, symptoms may not occur until fifteen to twenty years after asbestos exposure making it hard to correctly diagnose the disease. To help determine whether one has asbestos, a doctor may listen to the chest for crackling sounds; additionally, he or she may run chest x-rays, CT scans or a pulmonary function test (Henderson, 2006, para. 5). Unfortunately, there is no cure for asbestosis. The only treatments available may ease the pain and help with breathing. Most importantly, a victim to asbestosis must stop further exposure to the toxin before they proceed with potentially beneficial procedures such as postural drainage,

4 chest percussion, or vibration to remove scar tissue from the lungs. In some cases, a lung transplant may be required ("Asbestosis," 2010). Despite the grim prospect of this disease, asbestos can lead to a devastating type of cancer called mesothelioma. Mesothelioma Mesothelioma is a rare type of cancer that affects the mesothelium, a thin layer of cells which line the body s internal organs. Asbestos exposure through inhalation or indigestion causes inflammation of internal tissue which leads to mesothelioma and eventually organ failure. This horrific disease occurs four times more frequently in men than women and about three thousand cases of asbestos are diagnosed yearly in the US alone ("Mesothelioma," 2010, pg.1). Thirty percent of all cases are diagnosed in veterans, particularly navy veterans of World War II who were exposed to high concentrations of asbestos. The presence of the toxin was within the boiler rooms, engine rooms and sleeping quarters. There are five types of mesothelioma, pleural, peritoneal, pericardial, testicular and benign. Pleural mesothelioma manifests in the pleura or lining of the lungs; it is the most common type and affects about seventy percent of mesothelioma cases ("Mesothelioma," 2010, pg.2). The symptoms include shortness of breath, chest pain, persistent cough, fatigue, and lumps under chest skin. Peritoneal mesothelioma attacks the lining of the abdominal cavity called the peritoneal membrane; its symptoms consist of weight loss, abdominal pain and swelling, bowel obstruction, and nausea. Associated with heart palpitations, irregular heartbeat, chest pain, difficult breathing, and bight sweats, Pericardial mesothelioma occurs in the pericardium, the tissue which lines the heart; it accounts for nearly five percent of all cases. Testicular, the least common type manifests in the tunica

5 vaginalis of the testicle; evidence of the disease is shown through painful or painless testicular lumps. Finally, benign mesothelioma is a non-cancerous form of mesothelioma which can affect a person periodically throughout their lifetime. A problem with detecting asbestos exposure is that the symptoms of many asbestos caused diseases may not occur for up to fifty years after exposure; in fact, the symptoms for this cancer are often mistaken as less-serious conditions (Karmin, 1988, page 3). Doctors best hope for a clear diagnosis involves running imaging scans such as x-rays, CT scans, PET scan, and MRI scan in hope of determining the location, size, and type of cancer; a biopsy if often necessary to test for cancerous cells. The treatments include chemotherapy, radiation therapy, and surgery; however, all types other than benign are fatal and the life expectancy after diagnosis is usually less than one year. Prevention Because everyone will be exposed to asbestos at some point in time, there is no way to prevent disease. Extra precautions may be taken to avoid working in contaminated areas and tests can be run to test whether one has asbestos in his or her home; however because low levels of asbestos are present in the air, water, and soil, most people will not be able to tell if they are ill from asbestos until at least ten years after exposure; however, the most commonly afflicted people are those who expose themselves to the toxin on a regular basis ("Asbestos exposure and," 2009, para.2). Evidence from various studies at automotive industries, mining companies, and demolition sites suggest that there is no safe level of asbestos exposure. The government regulations help protect workers from high concentration exposure, but nothing can be done to

6 permanently remove asbestos. Those who are concerned about the level of asbestos in their homes can buy an Asbestos test which uses Polarized Light Microscopy (PLM) to identify asbestos ("Testing asbestos: professional," 1999, para. 2). The sample must be mailed in to be analyzed in the laboratory, but results usually arrive within five days. Houses contaminated with asbestos may either have the products containing asbestos covered up or removed to prevent the spread of the fibers into the air. Problems and Lawsuits When asbestos was finally recognized for its toxicity, it was too late for thousands of American workers who were unknowingly exposed to the toxin during the 20 th century. Asbestos was used in construction for Ground Zero and the former World Trade Center site; consequently, during the attack on the World Trade Center in New York City, hundreds of tons of asbestos were released into the atmosphere. Because of the relatively recent ban of asbestos for certain products, many companies are finding themselves in lawsuits over health care for workers who suffer from asbestosis or mesothelioma. Recently, a mine in Libby, Montana was relieved from charges of intentionally exposing people to asbestos. The old vermiculite mine, owned and run by the company W. R. Grace from , contained a significant amount of asbestos which has since caused two hundred people out of 2,600 to die from diseases related to asbestos exposure (Johnson, 2009, pg.3). However, the Federal District Court in Missoula decided that the contamination was not criminal. Many lawsuits similar to this have arisen and the government has been forced to regulate asbestos production and pay back the affected people whose health they ignored by failing to test the effects of asbestos prior to its production.

7 Current regulations In 1989, the health hazards of asbestos were recognized by the government and addressed to protect human wealth fare. The production of all new uses for asbestos was banned. The U.S. Environmental Protection Agency (EPA) required schools to search the buildings for products containing asbestos and to either eliminate or reduce the asbestos by removing it or covering it up. The EPA also began the regulation of the release of asbestos from factories and the release of asbestos into the air during either building demolition or renovation which could potentially stir up asbestos without proper precautions. The current concentration limit is seven million fibers per liter of drinking water for fibers greater than or equal to five µm; additionally, the Occupational Safety and Health Administration limits 100,000 fibers (greater than or equal to five µm in length) per cubic meter of workplace air. Despite the precautions taken to prevent high concentration exposure, humans are inevitably at risk. Because of the huge production of asbestos during the 20 th century and the presence of asbestos within products today, the only way to dispose of the toxin is to hope that it will eventually become buried deep into the earth s crust where it will not harm human life. For now, humans will continue to be exposed to fibers per milliliter of air every day.

8 Literature Cited Asbestos exposure and cancer risk. (2009, May 01). Retrieved from Asbestosis. (2010, March 23). Retrieved from Ciullo, P. A. (1996). Industrial minerals and their uses a handbook and formulary. Retrieved from Henderson, V. L., & Enterline, P. E. (2006). Asbestos exposure: factors associated with excess cancer and respiratory disease mortality. Annals of the New York Academy of Sciences, 330. Retrieved from &SRETRY=0 doi: How to purify the air in your home. (2010). Retrieved from Johnson, K. (2009, May 8). Chemical company is acquitted in asbestos case. Retrieved from Kamrin, M. A. (1988). Toxicology. Chelsea: Lewis Publishers Asbestos. (1996). The Merck index. Whitehouse Station, NJ: Merck & CO. Inc. Mesothelioma. (2010, March 19). Retrieved from Testing asbestos: professional asbestos test kits, asbestos management tips, asbestos testing kit. (1999). Retrieved from