Showing posts with label Asbestos. Show all posts
Showing posts with label Asbestos. Show all posts

Friday, August 28, 2009

Type of Asbestos | The Resource of Asbestos Exposure

The term "asbestos" refers to six fibrous minerals that have been commercially exploited and occur naturally in the environment. The U.S. Bureau of Mines has named more than 100 mineral fibers as "asbestos-like" fibers, yet only six are recognized regulated by the U.S. government. This is largely due to influential lobbying by the asbestos and stone industries, which powerfully shaped how the public perceives asbestiform minerals.

The six asbestiform minerals recognized by the government include, tremolite asbestos, actinolite asbestos, anthophyllite asbestos, chrysotile asbestos, amosite asbestos, and crocidolite asbestos. Each of these minerals is categorized into two groups, serpentine and amphibole. Chrysotile asbestos is the only member of the serpentine group and the others belong to the amphibole group. The difference between these two groups is characterized by the physical components of the asbestos fibers. The serpentine group is made up of minerals that have a layered form and curly fibers and the latter group contains minerals that have straight fibers with a chain-like structure.

In order to fully understand the importance and function of these minerals, it is necessary to examine each mineral in more detail.

Chrysotile Asbestos



Chrysotile asbestos is better known as white asbestos and is made up of fine, silky, flexible white fibers. Chrysotile consists of minerals crystallized in a serpentine pattern, which means its crystals are formed in sheets. This is the most common type of asbestos comprising approximately 95 percent of all asbestos commercially used in the United States. Due to the widespread use of this fiber, chrysotile accounts for the majority of asbestos-related health problems throughout the world.

Chrysotile, as well as other forms of asbestos, is considered to be a human carcinogen by the International Agency for Research on Cancer (IARC) and by the U.S. Department of Health and Human Services. Asbestos exposure is associated with parenchymal asbestosis, asbestos-related pleural abnormalities, mesothelioma, and lung cancer, and it may be associated with cancer at some extra-thoracic sites.

Tremolite Asbestos




Tremolite is a relatively common mineral found in most metamorphic rocks. Its color ranges from a creamy white to dark green. Tremolite asbestos has been used for industrial purposes (though not as much as chrysotile) and has been identified as an ingredient in some household products, primarily talcum powder (which is also a known carcinogen). This form of asbestos is the major asbestiform contaminant of the infamous vermiculite mine in Libby, Montana.

The Mineral Tremolite:

* Chemistry: Ca2Mg5Si8O22(OH)2 , Calcium Magnesium Silicate Hydroxide.
* Class: Silicates
* Subclass: Inosilicates
* Group: Amphibole
* Uses: Asbestos and as a mineral specimen.

Tremolite is a relatively common mineral in some metamorphic rocks. It occurs from the conversion of dolomite, silica and water into tremolite, calcite and carbon dioxide

A fibrous variety of tremolite is used as asbestos. This material is toxic and inhaling the fibers can lead to asbestosis, lung cancer and mesothelioma.

Actinolite Asbestos

Actinolite Asbestos

Actinolite asbestos is a relatively common mineral existing in metamorphic rocks. This type of asbestos is usually green, white, or gray and it is closely related to the aforementioned tremolite mineral (actinolite contains a greater presence of iron over magnesium than tremolite).

Actinolite is composed of the elements calcium, magnesium, iron, silicon, oxygen, and hydrogen.

Scientists and medical professionals have confirmed that actinolite and other forms of asbestos are human carcinogens. Exposure to these minerals can lead to the development of asbestos-related cancers, such as lung cancer and mesothelioma cancer.

In addition to these sources of actinolite asbestos, evidence indicates that actinolite may be found in children's toys, drywall compounds, joint compounds, and a number of other products. Considering the evidence, thousands of people may have been unknowingly exposed to actinolite asbestos through products or environmental conditions. No matter the source, whether it's a pipe sealant in the home or an environmental contamination in a community, actinolite is extremely harmful to human health.

Anthophyllite Asbestos



Anthophyllite asbestos is commonly identified by its brittle white fibers that are made of crystals and have a chain-like appearance. This type of asbestos is formed by the breakdown of talc in ultramafic rock, and as such, anthophyllite is a common contaminant of talc. Anthophylite is the product of metamorphism of magnesium-rich rocks especially ultrabasic igneous rocks and impure dolomitic shales.

The Mineral ANTHOPHYLLITE:

* Chemistry: (Mg, Fe)7Si8O22(OH)2 , Magnesium Iron Silicate Hydroxide.
* Class: Silicates
* Subclass: Inosilicates
* Group: Amphibole
* Uses: Are limited to some asbestos uses and as mineral specimens.

Like other forms of asbestos, anthophyllite poses a serious health threat. Several decades ago, health authorities and scientists confirmed anthophyllite is a human carcinogen. When people come into contact with anthophyllite asbestos and inhale or ingest its fibers, the fibers have the potential to become lodged in the mesothelial lining of the lungs, heart, abdomen, or testicles. The fibers can eventually lead to the development of lung cancer, mesothelioma cancer, and other life-threatening cancers and illnesses.

In addition to being intentionally used in a number of popular consumer products, anthophyllite has also been a common contaminant in talc, the mineral from which this deadly material is derived. According to studies, anthophyllite is formed when high temperatures are sustained, which destabilizes the talc mineral and causes it to disintegrate. The geologic link between these two minerals serves as an explanation of the occasional (less common today than three decades ago) contamination of talc with anthophyllite asbestos, which has been observed in scientific studies of talc at a weight as low as 2 percent of the total mineral weight. Because talcum powders and other products made from talc may contain anthophyllite asbestos, thousands of consumers - including countless infants and children - may have been exposed to anthophyllite, which is known to cause serious illnesses such as asbestosis, lung cancer, and mesothelioma.

Individuals living various lifestyles and working in a slew of occupations may have been exposed, from painters to construction workers to shipyard workers, just to name a few. Those who have worked with or otherwise used asbestos-containing products such as those described above may have been exposed to anthophyllite asbestos. Additionally, those who believe they may be at risk for developing an asbestos-related illness should contact an experienced mesothelioma lawyer. A mesothelioma lawyer can help answer any questions about anthophyllite and other forms of asbestos, as well as offer information on the legal options available to victims of asbestos exposure.

Amosite Asbestos



Amosite asbestos is an amphibole.
Amosite asbestos is identified by its straight, brittle fibers that are light gray to brown in color. Amosite is also referred to as brown asbestos and its name is derived from the asbestos mines located in South Africa.

The amosite variety of asbestos was used primarily as a fire retardant in thermal insulation products, like ceiling tiles, roof tiles, floor tiles, plumbing insulation, insulation board, chemical insulation, gaskets, lagging, cement sheet, electrical and telecommunication insulation.

Brown asbestos is now banned in most countries and has been for a number of years, but it can still be found in older products and structures, therefore still posing potential dangers, especially because this form of asbestos is highly friable. That means it crumbles easily when damaged, therefore releasing airborne fibers which can then be inhaled by those in the vicinity of the material.

As a form of asbestos, amosite has caused many cases of cancer (including mesothelioma) in people of many countries, but especially near the amosite mines in South Africa, the world's main commercial source of amosite. The workers who mined and processed amosite have cancer rates far worse than those of the general population.

The fibers of amosite are long and thin, and they can be broken into smaller, needle-like pieces. Fragments of amosite fibers are sometimes identified in building materials. As with other types of asbestos (there are six types in all), amosite is less of a danger when it is "trapped" in place in a product. It is when the amosite is being installed, removed or manipulated — or when its fibers are released into the air because of deterioration or damage — that the human beings in the area are vulnerable to asbestos inhalation.

Crocidolite Asbestos



Crocidolite asbestos, better known as blue asbestos, because of its color that ranges from pale green to indigo to Prussian blue. Crocidolite is harder than the other varieties of amphibole asbestos. This form is believed to be the most lethal form of asbestos. Crocidolite asbestos occurs naturally in locations such as Australia, South Africa, Bolivia, the former Soviet Union, and Canada.

Crocidolite asbestos is a form of asbestos known to cause mesothelioma. The fibers of crocidolite — or any other type of asbestos — can become lodged in the lungs or at other internal sites of the body, where they may initiate a process that culminates in asbestos diseases such as asbestosis, mesothelioma and lung cancer.

Some investigators have claimed that crocidolite is the cause of the great majority of mesotheliomas in the world, including most cases from the United States. Since crocidolite was rarely used in shipyards and in insulation products in this country (the source of a large proportion of mesotheliomas in the U.S.), we investigated our files for the proportion of the various asbestos fiber types found in the lungs of patients with mesothelioma. The data summarized below include analyses from more than 1500 fibers from 94 patients with mesothelioma.

MESOTHELIOMA AND FIBER TYPE

Studies of the mineral fiber content of lung in U.S. patients with mesothelioma have shown that amosite is the most common fiber type, accounting for nearly 60% of all fibers 5 or greater in length among more than 1500 fibers analyzed from 94 cases. Ten percent of the fibers analyzed were tremolite, and 3% were chrysotile. (Chrysotile tends to break down in the lungs over time so that there is a relative enrichment of the more stable tremolite contaminant). Crocidolite accounted for only 3% of fibers. Studies have shown that fibers in this size range are capable of reaching the visceral and parietal pleura.

The last five amphibole (which translates to "ambiguous" in Greek) types have a slightly more complex crystal structure than chrysotile and are not used as extensively in commercial products as chrysotile. Due to their structure, amphiboles tend to stay in the lungs longer than chrysotile and are more likely to cause illness because of this factor. Some hypothesize very small contaminations of amphibole fibers within chrysotile are most to blame for cancer deaths caused by asbestos exposure.

Asbestiform minerals are found in serpentine and ultramafic rock. These rocks are located throughout the United States, especially near mountainous regions. California is exceptionally bountiful in asbestos, where the mineral can be found in at least 44 of the state's 58 counties (some geologists report asbestos is found in 50 of the 58 counties). Asbestos fibers especially form near fault zones, where temperature, pressure, and time have transformed the molecules into the asbestiform crystals.

Why is Asbestos Used?

The mineral's innate resistance to heat and fire is what has made asbestos so valuable in both industrial and domestic products. Another valuable feature is its reluctance to conduct electricity. The fibers are fine, flexible and can be spun into thread and woven into cloth that is flameproof, difficult to tear, and carries excellent insulation properties. It is virtually indestructible by heat, salt water, corrosive chemicals (especially alkalies), and any chemical or biological process. The fibers mix well into other materials, such as asphalt or cement, and make such products stronger, more flexible, and fire-retardant. They do not dissolve or evaporate with water, which makes the light fibers easy to mix.

resource : Asbestos.com

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Asbestos Exposure Increase The Risk of Cancer

What are the Health Hazards of Exposure to Asbestos?

Exposure to asbestos may increase the risk of several serious diseases:

• Asbestosis—a chronic lung ailment that can produce shortness of breath, coughing, and permanent lung damage;
• Lung cancer;
• Mesothelioma—a relatively rare cancer of the thin membranes that line the chest and abdomen; and
• Other cancers, such as those of the larynx, oropharynx, gastrointestinal tract, and kidney.

While all types of asbestos fibers may increase the risk of developing these diseases, some scientists believe that crocidolite and amosite are more likely to produce mesotherlioma than is chrysotile. However, because most workers have been exposed to a variety of asbestos fiver types during their lifetime, it has not yet been possible to confirm this finding.

People may be exposed to asbestos in their workplace, their communities, or their homes. If products containing asbestos are disturbed, tiny asbestos fibers are released into the air. When asbestos fibers are breathed in, they may get trapped in the lungs and remain there for a long time. Over time, these fibers can accumulate and cause scarring and inflammation, which can affect breathing and lead to serious health problems .

Asbestos has been classified as a known human carcinogen (a substance that causes cancer) by the U.S. Department of Health and Human Services, the EPA, and the International Agency for Research on Cancer. Studies have shown that exposure to asbestos may increase the risk of lung cancer and mesothelioma (a relatively rare cancer of the thin membranes that line the chest and abdomen). Although rare, mesothelioma is the most common form of cancer associated with asbestos exposure. In addition to lung cancer and mesothelioma, some studies have suggested an association between asbestos exposure and gastrointestinal and colorectal cancers, as well as an elevated risk for cancers of the throat, kidney, esophagus, and gallbladder (3, 4). However, the evidence is inconclusive.

Asbestos exposure may also increase the risk of asbestosis (an inflammatory condition affecting the lungs that can cause shortness of breath, coughing, and permanent lung damage) and other nonmalignant lung and pleural disorders, including pleural plaques (changes in the membranes surrounding the lung), pleural thickening, and benign pleural effusions (abnormal collections of fluid between the thin layers of tissue lining the lungs and the wall of the chest cavity). Although pleural plaques are not precursors to lung cancer, evidence suggests that people with pleural disease caused by exposure to asbestos may be at increased risk for lung cancer .

How great is the risk?

Not all workers exposed to asbestos will develop diseases related to their exposure. The risk of developing asbestos-related diseases varies with the type of industry in which the exposure occurred and with the extent of the exposure. Asbestos that is bonded into finished products such as walls and tiles poses no risk to health as long as it is not damaged or disturbed (for example, by sawing or drilling) in such a way as to release fibers into the air. When asbestos fibers are set free and inhaled, however, exposed individuals are at risk of developing an asbestos-related disease.
In addition, different types of asbestos fibers may be associated with different health risks. For example, results of several studies suggest that amphibole forms of asbestos may be more harmful than chrysotile, particularly for mesothelioma. Even so, no fiber type can be considered harmless, and people working with asbestos should always take proper safety precautions to limit exposure.


Who is at risk for an asbestos-related disease?

Everyone is exposed to asbestos at some time during their life. Low levels of asbestos are present in the air, water, and soil. However, most people do not become ill from their exposure. People who become ill from asbestos are usually those who are exposed to it on a regular basis, most often in a job where they work directly with the material or through substantial environmental contact.

Since the early 1940s, millions of American workers have been exposed to asbestos. Health hazards from asbestos fibers have been recognized in workers exposed in the shipbuilding trades, asbestos mining and milling, manufacturing of asbestos textiles and other asbestos products, insulation work in the construction and building trades, and a variety of other trades. Demolition workers, drywall removers, asbestos removal workers, firefighters, and automobile workers also may be exposed to asbestos fibers. Studies evaluating the cancer risk experienced by automobile mechanics exposed to asbestos through brake repair are limited, but the overall evidence suggests there is no safe level of asbestos exposure (3, 8). As a result of Government regulations and improved work practices, today’s workers (those without previous exposure) are likely to face smaller risks than did those exposed in the past.

Individuals involved in the rescue, recovery, and cleanup at the site of the September 11, 2001, attacks on the World Trade Center (WTC) in New York City are another group at risk of developing an asbestos-related disease. Because asbestos was used in the construction of the North Tower of the WTC, when the building was attacked, hundreds of tons of asbestos were released into the atmosphere. Those at greatest risk include firefighters, police officers, paramedics, construction workers, and volunteers who worked in the rubble at Ground Zero. Others at risk include residents in close proximity to the WTC towers and those who attended schools nearby. These individuals will need to be followed to determine the long-term health consequences of their exposure (10).

One study found that nearly 70 percent of WTC rescue and recovery workers suffered new or worsened respiratory symptoms while performing work at the WTC site. The study describes the results of the WTC Worker and Volunteer Medical Screening Program, which was established to identify and characterize possible WTC-related health effects in responders. The study found that about 28 percent of those tested had abnormal lung function tests, and 61 percent of those without previous health problems developed respiratory symptoms (11). However, it is important to note that these symptoms may be related to exposure to debris components other than asbestos.

Although it is clear that the health risks from asbestos exposure increase with heavier exposure and longer exposure time, investigators have found asbestos-related diseases in individuals with only brief exposures. Generally, those who develop asbestos-related diseases show no signs of illness for a long time after their first exposure. It can take from 10 to 40 years or more for symptoms of an asbestos-related condition to appear (2).

There is some evidence that family members of workers heavily exposed to asbestos face an increased risk of developing mesothelioma (6). This risk is thought to result from exposure to asbestos fibers brought into the home on the shoes, clothing, skin, and hair of workers. To decrease these exposures, Federal law regulates workplace practices to limit the possibility of asbestos being brought home in this way. Some employees may be required to shower and change their clothes before they leave work, store their street clothes in a separate area of the workplace, or wash their work clothes at home separately from other clothes (2).

Cases of mesothelioma have also been seen in individuals without occupational asbestos exposure who live close to asbestos mines (6).
# What factors affect the risk of developing an asbestos-related disease?

Several factors can help to determine how asbestos exposure affects an individual, including (2, 6):

* Dose (how much asbestos an individual was exposed to).
* Duration (how long an individual was exposed).
* Size, shape, and chemical makeup of the asbestos fibers.
* Source of the exposure.
* Individual risk factors, such as smoking and pre-existing lung disease.

Although all forms of asbestos are considered hazardous, different types of asbestos fibers may be associated with different health risks. For example, the results of several studies suggest that amphibole forms of asbestos may be more harmful than chrysotile, particularly for mesothelioma risk, because they tend to stay in the lungs for a longer period of time (1, 2).

# How are asbestos-related diseases detected?

Individuals who have been exposed (or suspect they have been exposed) to asbestos fibers on the job, through the environment, or at home via a family contact should inform their doctor about their exposure history and whether or not they experience any symptoms. The symptoms of asbestos-related diseases may not become apparent for many decades after the exposure. It is particularly important to check with a doctor if any of the following symptoms develop (6):

* Shortness of breath, wheezing, or hoarseness.
* A persistent cough that gets worse over time.
* Blood in the sputum (fluid) coughed up from the lungs.
* Pain or tightening in the chest.
* Difficulty swallowing.
* Swelling of the neck or face.
* Loss of appetite.
* Weight loss.
* Fatigue or anemia.

A thorough physical examination, including a chest x-ray and lung function tests, may be recommended. The chest x-ray is currently the most common tool used to detect asbestos-related diseases. However, it is important to note that chest x-rays cannot detect asbestos fibers in the lungs, but they can help identify any early signs of lung disease resulting from asbestos exposure (2).

Studies have shown that computed tomography (CT) (a series of detailed pictures of areas inside the body taken from different angles; the pictures are created by a computer linked to an x-ray machine) may be more effective than conventional chest x-rays at detecting asbestos-related lung abnormalities in individuals who have been exposed to asbestos (12).

A lung biopsy, which detects microscopic asbestos fibers in pieces of lung tissue removed by surgery, is the most reliable test to confirm the presence of asbestos-related abnormalities. A bronchoscopy is a less invasive test than a biopsy and detects asbestos fibers in material that is rinsed out of the lungs. It is important to note that these tests cannot determine how much asbestos an individual may have been exposed to or whether disease will develop (12). Asbestos fibers can also be detected in urine, mucus, or feces, but these tests are not reliable for determining how much asbestos may be in an individual’s lungs (2).
# How can workers protect themselves from asbestos exposure?

The Occupational Safety and Health Administration (OSHA) is a component of the U.S. Department of Labor (DOL) and is the Federal agency responsible for health and safety regulations in maritime, construction, manufacturing, and service workplaces. OSHA established regulations dealing with asbestos exposure on the job, specifically in construction work, shipyards, and general industry that employers are required to follow. In addition, the Mine Safety and Health Administration (MSHA), another component of the DOL, enforces regulations related to mine safety. Workers should use all protective equipment provided by their employers and follow recommended workplace practices and safety procedures. For example, National Institute for Occupational Safety and Health (NIOSH)-approved respirators that fit properly should be worn by workers when required.

Workers who are concerned about asbestos exposure in the workplace should discuss the situation with other employees, their employee health and safety representative, and their employers. If necessary, OSHA can provide more information or make an inspection. Regional offices of OSHA are listed in the “United States Government” section of a telephone directory’s blue pages (under “Department of Labor”). Regional offices can also be found at http://www.osha.gov/html/RAmap.html on the Internet.

More information about asbestos is available on the OSHA Asbestos Web page, which has links to information about asbestos in the workplace, including what OSHA standards apply, the hazards of asbestos, evaluating asbestos exposure, and controls used to protect workers. This page is available at http://www.osha.gov/SLTC/asbestos/index.html on the Internet. OSHA’s national office can be contacted at:

What programs are available to help individuals with asbestos-related diseases?

Some people with asbestos-related illness may be eligible for Medicare coverage. Information about benefits is available from Medicare’s Regional Offices, located in 10 major cities across the United States and serving specific geographic areas. The Regional Offices serve as the agency’s initial point of contact for beneficiaries, health care providers, state and local governments, and the general public. Contact information for each Regional Office can be found at http://www.cms.hhs.gov/RegionalOffices on the Internet. General information about Medicare is available by calling toll-free 1–800–633–4227 (1–800–MEDICARE) or visiting http://www.medicare.gov on the Internet.

People with occupational asbestos-related diseases also may qualify for financial help, including medical payments, under state workers’ compensation laws. Because eligibility requirements vary from state to state, workers employed by private companies or by state and local government agencies should contact their state workers’ compensation board. Contact information for state workers’ compensation officials may be found in the blue pages of a local telephone directory or at http://www.dol.gov/esa/regs/compliance/owcp/wc.htm on the Internet.

If exposure occurred during employment with a Federal agency, medical expenses and other compensation may be covered by the Federal Employees’ Compensation Program, which is administered by the DOL, Employment Standards Administration’s Office of Workers’ Compensation Programs. This program provides workers’ compensation benefits to Federal (civilian) employees for employment-related injuries and diseases. Benefits include wage replacement, payment for medical care, and, where necessary, medical and vocational rehabilitation assistance in returning to work. Benefits may also be provided to dependents if the injury or disease causes the employee’s death. The program has 12 district offices nationwide.

In addition, the Longshore and Harbor Workers’ Compensation Program provides benefits to longshoremen, harbor workers, other maritime workers, and other classes of private industry workers who are injured during the course of employment or suffer from diseases caused or worsened by conditions of employment. Information about eligibility and how to file a claim for benefits under either of these programs is available from:
Organization: Office of Workers’ Compensation Programs
Employment Standards Administration
U.S. Department of Labor
Address: Frances Perkins Building
200 Constitution Avenue, NW.
Washington, DC 20210
Telephone: 1–866–692–7487 (1–866–OWCPIVR)
202–693–0040
(Federal Employees’ Compensation Program)
202–693–0038
(Longshore and Harbor Workers’ Compensation Program)
E-mail: OWCP-Public@dol.gov
Internet Web site: http://www.dol.gov/esa/owcp/index.htm

Eligible veterans may receive health care at a Department of Veterans Affairs (VA) Medical Center for an asbestos-related disease. Veterans can receive treatment for service-connected and nonservice-connected medical conditions. Information about eligibility and benefits is available from the VA Health Benefits Service Center at 1–877–222–8387 (1–877–222–VETS) or on the VA Web site at http://www1.va.gov/health/index.asp on the Internet.
# Is there Federal legislation to help victims of asbestos-related diseases?

No Federal legislation has been enacted to compensate victims of asbestos-related diseases or to protect people from asbestos exposure. However, a bill called the Fairness in Asbestos Injury Resolution Act, or FAIR Act, has been introduced in Congress several times. This bill would create a national trust fund to compensate victims suffering from asbestos-related diseases. The proposed trust fund would be administered by the DOL, outside of the courts, through a claims process in which all individuals with certain medical symptoms and evidence of asbestos-related disease would be compensated. Funding for the trust would come from insurance companies and companies that mined, manufactured, and sold asbestos or asbestos products. Under the bill, individuals affected by asbestos exposure would no longer be able to pursue awards for damages in any Federal or state court.

What other organizations offer information related to asbestos exposure?

The organizations listed below can provide more information about asbestos exposure.

The Agency for Toxic Substances and Disease Registry (ATSDR) is the principal Federal agency responsible for evaluating the human health effects of exposure to hazardous substances. This agency works in close collaboration with local, state, and other Federal agencies, with tribal governments, and with communities and local health care providers to help prevent or reduce harmful human health effects from exposure to hazardous substances. The ATSDR provides information about asbestos and where to find occupational and environmental health clinics. The ATSDR can be contacted at:
Organization: Agency for Toxic Substances and Disease Registry
Address: 4770 Buford Highway, NE.
Atlanta, GA 30341
Telephone: 1–800–232–4636 (1–800–CDC–INFO)
TTY: 1–888–232–6348
E-mail: cdcinfo@cdc.gov
Internet Web site: http://www.atsdr.cdc.gov

The U.S. Environmental Protection Agency (EPA) regulates the general public’s exposure to asbestos in buildings, drinking water, and the environment. The EPA offers a Toxic Substances Control Act (TSCA) Hotline and an Asbestos Ombudsman. The TSCA Hotline provides technical assistance and information about asbestos programs implemented under the TSCA, which include the Asbestos School Hazard Abatement Act and the Asbestos Hazard Emergency Response Act. The Asbestos Ombudsman focuses on asbestos in schools and handles questions and complaints. Both the TSCA Hotline and the Asbestos Ombudsman can provide publications on a number of topics, particularly on controlling asbestos exposure in schools and other buildings. The Ombudsman operates a toll-free hotline for small businesses, trade associations, and others seeking free, confidential help.

The EPA Web site includes a list of EPA regional and state asbestos contacts at http://www.epa.gov/asbestos/pubs/regioncontact.html on the Internet. In addition, EPA’s Asbestos and Vermiculite home page provides information about asbestos and its health effects and links to asbestos resources, including suggestions for homeowners who suspect asbestos in their homes, and laws and regulations applicable to asbestos. This page can be found at http://www.epa.gov/asbestos on the Internet. Questions may be directed to:
Organization: U.S. Environmental Protection Agency
EPA West Building
National Program Chemicals Division
Address: Mail Code 7404T
1200 Pennsylvania Avenue, NW.
Washington, DC 20460
TSCA Hotline: 202–554–1404
TTY: 202–554–0551
Asbestos Ombudsman: 1–800–368–5888
E-mail: tsca-hotline@epa.gov
Internet Web site: http://www.epa.gov/asbestos

Another EPA resource that may be of interest is the brochure titled Current Best Practices for Preventing Asbestos Exposure Among Brake and Clutch Repair Workers. Released in April 2007, this brochure includes work practices for both automotive professionals and home mechanics that may be used to avoid asbestos exposure. It also summarizes existing OSHA regulatory requirements for professional auto mechanics. The brochure can be found at http://www.epa.gov/asbestos/pubs/brakesbrochure.html on the Internet.

The U.S. Consumer Product Safety Commission (CPSC) is responsible for protecting the public from unreasonable risks of serious injury or death from more than 15,000 types of consumer products, including asbestos, under the agency’s jurisdiction. The CPSC maintains a toll-free 24-hour hotline where callers can obtain product safety and other agency information and report unsafe products. In addition, CPSC publications provide guidelines for repairing and removing asbestos, and general information about asbestos in the home. CPSC can be contacted at:
Organization: Office of Information and Public Affairs
U.S. Consumer Product Safety Commission
Address: 4330 East West Highway
Bethesda, MD 20814
Telephone: 1–800–638–2772
TTY: 1–800–638–8270
E-mail: info@cpsc.gov
Internet Web site: http://www.cpsc.gov

Individuals can also contact their local or state health department with questions or concerns about asbestos.

resource: Geneese County

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Wednesday, September 24, 2008

Lung Cancer Disease

What is Lung Cancer?



Also called: Bronchogenic carcinoma

Lung cancer is a malignant (cancerous) tumor that starts from cells of the lung.

The lungs are a pair of sponge-like organs found in the chest that take in oxygen when we breathe in and get rid of carbon dioxide when we breathe out. The right lung is a bit larger than the left lung, which is smaller to accommodate for the size of the heart on the left side of the body. The right lung has three sections, called lobes, and the left lung has two.

Lung cancer is the rapid growth of abnormal cells in the lung. It can start anywhere in the lungs and affect any part of the respiratory system.

Lung cancer is the leading cause of cancer deaths in both men and women. Fewer than half of the people who develop lung cancer live 1 more year. And only 15% of people who develop lung cancer live for 5 more years.


Type of Lung Cancer



Lung cancer is commonly divided into two types:

  1. Small Cell Lung Cancer (SCLC). Small cell lung cancer spreads early in the course of the disease and occurs almost exclusively in smokers. Surgical removal usually isn't an option for this type of cancer; instead, it's best treated with chemotherapy and radiation. Even so, the five-year survival rate for small cell lung cancer is very low.
  • Non-Small Cell Lung Cancer (NSCLC). Non-small cell lung cancer, which is more common, accounts for more than 75 percent of lung cancers. If caught early when it's confined to a small area, it often can be removed surgically. There are four major categories of non-small cell lung cancer:
  • Squamous cell carcinoma: is a cancer that begins in squamous cells, which are thin, flat cells found in the passages of the respiratory and digestive tracts as well as in the surface of the skin and the lining of the hollow organs of the body. This type of NSCLC is linked to a history of smoking and usually found centrally, near a bronchus. It is also called epidermoid carcinoma. This cancer forms in cells lining the airways. It's the most common type in men.
  • Adenocarcinoma: This type of cancer usually begins in the mucous-producing cells of the lung. It's the most common type in women and in people who have never smoked or were exposed to secondhand smoke.
  • Large cell carcinoma: is a type of lung cancer in which the cells are large and look abnormal when viewed under a microscope. It can be found in any part of the lung and tends to grow and spread rapidly. This type of cancer originates in the peripheral part of the lungs.
  • Bronchoaveolar carcinoma: This uncommon type of non-small cell lung cancer tends to grow more slowly than other forms of the disease. It occurs more often in smokers than in nonsmokers and tends to arise in more than one location at the same time.
What causes lung cancer?

Although smoking is by far the leading risk factor for lung cancer, it is known that there are several other risk factors linked to the disease. Some of the risk factors for lung cancer are discussed below:

1. Smoking

Tobacco smoking is believed to be responsible for 80 percent of all cases of lung cancer. The risk of lung cancer increases with the length of time a person has been smoking, the number of packs per day smoked, and how deeply the smoke is inhaled. However, if a person quits smoking before lung cancer develops, the lung tissue slowly returns to normal, which lowers the risk of lung cancer.

Some people think that smoking cigars and pipes is less harmful than smoking cigarettes. However, research has shown that cigar and pipe smoking are almost as likely to cause lung cancer as cigarette smoking. Even cigar and pipe smokers who do not inhale are at increased risk for lung, mouth and other types of cancers.

Secondhand smoke, also called environmental tobacco smoke, describes the smoke in the air when someone else smokes. Exposure to secondhand smoke is called involuntary or passive smoking and increases lung cancer risk. For example, nonsmoking spouses of smokers and people exposed to tobacco smoke in the workplace are more likely to get lung cancer.

2. Asbestos

Asbestos is any of several minerals that occur naturally as fibers. These fibers tend to break easily into particles, which can float in the air and become inhaled, where they can lodge in the lungs, damaging cells and increasing the risk for lung cancer. Formerly used as fireproof insulating materials, asbestos is rarely used today in the workplace or in home products, as it has since been implicated as a cause of certain cancers.

Workers who have been exposed to large amounts of asbestos — such as those in industries like shipbuilding, insulation work, and asbestos mining and manufacturing — have a higher risk of getting lung cancer. The risk of lung cancer is even higher among asbestos workers who also smoke.

3. Radon

Radon is an invisible, odorless and tasteless radioactive gas that occurs naturally in soil and rock. It can cause damage to the lungs that may lead to lung cancer. People who work in mines may be exposed to radon; occasionally, radon can also accumulate indoors. Radon levels in homes may be measured by a kit found in most hardware stores.

4. Marijuana

Many of the carcinogens found in tobacco are also found in marijuana, which actually has more tar than regular cigarettes. Research suggests that marijuana may also cause cancers of the mouth and throat.

5. Lung diseases

Certain lung diseases, such as tuberculosis and some types of pneumonia, often leave scars on the lung that can increase the risk of developing lung cancer.

6. Personal and family history

A person who has had lung cancer once is at increased risk for developing a second lung cancer. Siblings and children of people who have had lung cancer may also have a slightly higher risk.

What are the symptoms of lung cancer?

Because most lung cancers do not cause any symptoms until they have spread, only about 15 percent of lung cancers are found in the early stages. When lung cancer is found early, it is often as a result of a chest X-ray, CT scan or other test that was being done for another reason. Symptoms of lung cancer may include:
  • A cough that does not go away and gets worse over time.
  • Constant chest pain, often made worse by deep breathing.
  • Hoarseness.
  • Weight loss and loss of appetite.
  • Coughing up blood.
  • Shortness of breath.
  • Recurring infections such as bronchitis and pneumonia.
  • New onset of wheezing.
  • Swelling of the neck and face.
Remember that these symptoms may be caused by conditions other than lung cancer. It is important to check with a doctor.

Diagnostic Tests for Lung Cancer:



If there is any reason to suspect lung cancer, the doctor will take a medical history and conduct a physical exam. The doctor may also order a chest X-ray and other tests. If lung cancer is suspected, sputum cytology (the microscopic examination of cells obtained from a deep-cough sample of mucus in the lungs) is a simple test that may be useful in detecting lung cancer.

To confirm the presence of lung cancer, the doctor must examine tissue from the lung. A biopsy — the removal of a small sample of tissue for examination under a microscope by a pathologist — can show whether a person has cancer. A number of procedures may be used to obtain this tissue:

* Bronchoscopy: The doctor puts a bronchoscope (a thin, lighted tube) into the mouth or nose and down through the windpipe and into the bronchi. This test can help find tumors or it can be used to take samples of tissue or fluids to see if cancer cells are present.

* Needle aspiration: A needle is inserted through the chest into the tumor to remove a sample of tissue.

* Thoracentesis: Using a needle, the doctor removes a sample of the fluid that surrounds the lungs. This test is done to check whether fluid around the lungs is caused by cancer or by a benign condition such as heart failure or an infection.

* Thoracotomy: Surgery to open the chest is sometimes needed to diagnose lung cancer. This procedure is a major operation performed in a hospital.

If the diagnosis is cancer, the doctor will conduct additional tests to determine the stage (or extent) of the disease (stages of lung cancer are discussed later). Some tests used to determine the cancer stage include:

* Computed tomography (CT) scan: A CT scan is an X-ray procedure in which the X-ray beam moves around the body, taking pictures from different angles. These images are combined by a computer to produce a detailed cross-sectional picture of the inside of the body.

* Magnetic resonance imaging (MRI): MRI uses large magnets and radio waves to produce computer-generated cross-sectional pictures of internal organs.

* Radionuclide scanning: Scanning can show whether cancer has spread to other organs, such as the liver. The patient swallows or receives an injection of a mildly radioactive substance. A machine (scanner) measures and records the level of radioactivity in certain organs to reveal abnormal areas.

* Bone scan: A bone scan is a type of radionuclide scanning that can show whether cancer has spread to the bones.

* Mediastinoscopy: A mediastinoscopy can help show whether the cancer has spread to the lymph nodes in the chest. With the patient asleep, tissue samples are taken from the lymph nodes along the windpipe through a small hole cut into the neck. Examining the tissue under a microscope can show if cancer cells are present.

* Bone marrow biopsy: A needle is used to remove a small piece of bone, usually from the back of the hipbone, and the sample is checked for cancer cells.

* Blood tests: Certain blood tests are often done to help see if the lung cancer has spread to the liver or bones.

Lung Cancer Treatment

Lung cancer treatment depends on the type and stage of cancer, as well as the overall health of the patient.

Treatment may include surgery to remove the cancer, radiation therapy, or medications (chemotherapy). Treatment for non–small and small cell cancer may be different.

Lung cancer treatment may include one or more of the following therapies:

1. Surgery

Surgery is taking out the cancer. Surgery is the most effective treatment for early-stage non–small cell lung cancers (stages I and II). In some cases, only the portion of the lung that contains the tumor is removed. In others, one lobe or even the entire lung may be taken. Surgery to remove all or part of a lung often involves opening one side of the chest, a procedure called a thoracotomy.

Operations to treat lung cancer include:
  • Wedge resection: In this operation, the doctor removes only the section of the lung that contains the tumor along with a margin of normal tissue.
  • Lobectomy: The most common type of surgery, lobectomy involves removing an entire lobe of one lung.
  • Pneumonectomy: In this operation, an entire lung is removed. Because pneumonectomy will decrease lung function considerably, as well as lead to other complications, it's performed only when absolutely necessary and then only if the patient breathing capacity is sufficient to allow breathing with a single lung.
Lung function studies and a lung scan are often done before surgery to predict whether the patient will have enough remaining lung function after surgery to live a fairly normal life.

2. Radiation therapy

Radiation therapy uses high-dose X-rays to kill cancer cells. Radiation therapy is often used in combination with surgery or chemotherapy or both. Radiation following surgery for stages IIA, IIB, and IIIA (with lymph node involvement) may reduce the risk of cancer returning in the chest.

The way in which radiation is delivered depends on the type and stage of the cancer being treated. Radiation therapy may be given before, during or after chemotherapy. In all cases, however, the goal of treatment is to destroy cancer cells while harming as little normal tissue as possible.

Small cell lung cancer often spreads to the brain. For that reason, the doctor may sometimes recommend brain radiation therapy to prevent cancer from metastasizing to that part of the body or to eliminate micrometastases that aren't yet detectable with imaging studies. Brain radiation therapy can cause short-term memory problems, fatigue, nausea and other serious side effects.

3. Chemotherapy

Because most small cell lung cancers have spread beyond the lungs by the time they're discovered, an operation usually isn't a treatment option. Instead the most effective treatment is chemotherapy, either alone or in combination with radiation therapy.

Chemotherapy uses medications or drugs to kill cancer cells. Chemotherapy is the most effective treatment for small cell lung cancer, but it is only a cure in a small number of people. Chemotherapy has been shown to improve survival in non-small lung cancer when it is given after surgery for stages IB, IIA, IIB, and IIIA. It may also be used to treat more advanced stages (stages III and IV) of non–small cell lung cancer.

In cases of small cell lung cancer, chemotherapy may be used to shrink the cancer, to slow the cancer's growth, to prevent it from spreading further, or to relieve symptoms and make the patient more comfortable (palliative care). A combination of drugs usually is given in a series of treatments over a period of weeks or months, with breaks in between so that the body can recover. Even so, because the drugs damage healthy cells along with malignant ones, they can cause serious side effects.

4. Targeted therapy

Targeted therapies use medications or antibodies to block growth factors that allow some cancers to grow. At this time, targeted therapies are used for advanced stages.

resource: Cancer Info Guide

Staging of Lung Cancer:

TNM staging is a process to measure how advanced the cancer is. The following three factors are considered:

* Tumor - size and location
* Node - lymph node involvement
* Metastasis - has the cancer spread

1. Small cell lung cancer staging:

Limited stage : The cancer is only in one lung and in lymph nodes on the same side of the chest.

Extensive stage
: The cancer has spread to the other lung, to lymph nodes on the other side of the chest, or to distant organs. Many doctors consider cancer that has spread to the fluid around the lung to be extensive stage as well.

2. Non-small cell lung cancer staging:

Stage 0 : The cancer is limited to the lung and is found in a few layers of cells only. It has not grown through the top lining of the lung. Stage 0 is also called carcinoma in situ.

Stage : The cancer is in the lung only, with normal tissue around the tumor. Stage I is divided into stages IA and IB, based on the size of the tumor.

Stage II : The cancer has spread to nearby lymph nodes or to the chest wall (the ribs and muscles that make up the area of the body between the neck and abdomen); the diaphragm (thin muscle below the lungs and heart that separates the chest from the abdomen); the mediastinal pleura (thin membrane that covers the outside of the lungs in the area near the heart); or the parietal pericardium (outer layer of tissue that surrounds the heart). Stage II is divided into stage IIA and stage IIB, based on the size of the tumor and whether it has spread to the lymph nodes.

Stage III : The cancer has either:
* Spread to the lymph nodes in the mediastinum (middle area between the lungs that contains the heart, major blood vessels and other structures);or
* Spread to the lymph nodes on the opposite side of the chest or in the lower neck.

Stage III is divided into stage IIIA (which is sometimes treated with surgery) and stage IIIB (which is rarely treated with surgery).

Stage IV : The cancer has spread to other parts of the body or to another lobe of the lungs.

Resource:
National Cancer Institute
MEDLINEplus Health Information
CancerGuide

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Asbestosis - Pulmonary Asbestosis Disease

What is Asbestosis?

Asbestosis is a chronic inflammatory lung disease that occurs due to long- term exposure to asbestos fibres .

Asbestosis is a breathing disorder caused by inhaling asbestos fibers. Prolonged accumulation of these fibers in your lungs can lead to scarring of lung tissue and diminished breathing capacity. Because many other diseases also lead to lung scarring, other causes must be excluded first when a patient is found to have lung scarring (pulmonary fibrosis).

Asbestosis particularly affects the parenchymatous tissues of the lungs and has gained increased significance due to its link to mesothelioma and to other forms of lung and laryngeal cancer. Asbestosis is also frequently associated with Chronic Obstructive Pulmonary Disease (COPD).

Asbestosis, as a medical problem, was recognized early in the 20th century. A few decades later studies established asbestosis as a predisposing factor for bronchogenic carcinoma and malignant mesothelioma. The developed countries have started recognizing the harmful effects of asbestos and have replaced it with synthetic metal fibres. Legislations have been passed globally to curtail its use in industries.

Patients with particular x-ray findings or biopsy results must also have a remote history of asbestos exposure and a characteristically delayed development of the condition in considering asbestosis as a diagnosis. Smoking appears to increase the frequency and/or the rate of progression of asbestosis, possibly by preventing the efficient elimination of inhaled fibers from the airways.

What are symptoms and signs of asbestosis?

The clinical symptoms usually include slowly progressing shortness of breath and cough, often 20 to 40 years after exposure to asbestos. Breathlessness advances throughout the disease, even without further asbestos inhalation. In the absence of cigarette smoking, sputum (mucus coughed up from the lungs) production and wheezing are uncommon. The exception is workers who have been exposed to very high concentrations of asbestos fibers. Those workers may also develop symptoms as soon as 10 years after exposure. Other indications of asbestosis include abnormal lung sounds on examination, changes in the ends of the fingers and toes ("clubbing"), a blue tinge to the fingers or lips ("cyanosis"), and failure of the right side of the heart ("cor pulmonale"). Asbestosis can be a progressive disease even after exposure to asbestos has stopped.

Signs and symptoms develop when damage and scarring caused by the asbestos fibers lead to stiffness in your lung tissue so that your lungs can't contract and expand normally (a form of pulmonary fibrosis). Once exposure to asbestos is stopped, however, the fibrosis does not progress.

Some asbestosis symptoms include:

* Shortness of breath, initially only with exertion, but eventually even while resting
* Decreased tolerance for physical activity
* Coughing
* Chest pain
* Finger clubbing in some cases

Although most of these signs and symptoms are similar to those of other breathing disorders, such as asthma, the way in which they develop is different. In asbestosis the effects of the disease are insidious, occurring over months and years.

Diagnosing Asbestosis





The diagnosis of asbestosis is made when there is a history of asbestos exposure and positive results from a clinical exam. There is a well-defined latency period of approximately 20 years or more between the initial exposure to asbestos and the development of asbestos related calcification and scarring.

Asbestosis can be diagnosed by the following tests:
  • Chest X-ray- irregular opacities in the lower lobes, heart border becomes shaggy. In the late stages of disease, there is a honey-comb likeness and volume loss. X rays can show shadows or spots on the lungs or an indistinct or shaggy outline of the heart that suggests the presence of asbestosis.
  • CT scan- scarring and thickening can be seen on the chest x-ray and CT, but the CT scan can detect calcifications around the lung (typical of asbestosis) more often. It is considered the most accurate means for detecting asbestos related abnormalities.
  • PFTs- pulmonary function testing is used to test for loss of lung volume, and for the impairment of movement of oxygen across the air sacs. Pulmonary function tests can be used to assess a patient's ability to inhale and exhale, and a computed tomography scan (CT) of the lungs can show flat, raised patches associated with advanced asbestosis.
  • Blood tests are used to measure concentrations of oxygen and carbon dioxide.
Complications

The severity of asbestosis is generally related to the amount and duration of exposure to asbestos. Effects of the disease may be so mild as to cause almost no symptoms. Or the condition may create such a reduced flow of oxygen as to be disabling or even fatal. Asbestosis may lead to the following conditions:
  • High blood pressure in your lungs. Asbestosis-related scar tissue may eventually compress or obliterate your lungs' small blood vessels, causing high blood pressure in your lungs' arteries (pulmonary hypertension).
  • Heart problems. Pulmonary hypertension can lead to enlargement and failure of your heart's right ventricle (cor pulmonale). Your heart consists of four chambers — two upper chambers called atria and two lower chambers called ventricles. Your right ventricle assists in pumping oxygen-poor blood from your organs and tissues to your lungs, where your blood receives a new boost of oxygen. As your pulmonary arteries narrow, your heart's right ventricle must work harder to pump blood through the lungs. Initially, the heart tries to compensate by thickening its walls and dilating the right ventricle to increase the amount of blood it can hold. But this measure only works temporarily, and eventually — after a period of a few years — the right ventricle weakens and fails from the extra strain.
  • Lung cancer. If you smoke and have asbestosis, your chances of developing lung cancer increase greatly, especially if you smoke more than a pack a day. Tobacco smoke and asbestos both contribute to each other's cancer-causing (carcinogenic) effects, so that the combination of both risk factors together is more dangerous than the effects of either risk factor alone.
  • Other lung damage. Exposure to asbestos can lead to other health complications including changes in the thin membranes covering your lungs and lining your chest cavity (pleural membranes). Pleural changes may be the first signs of asbestos exposure and may include pleural thickening, the formation of calcium deposits in the pleura (plaques), and an abnormal accumulation of fluid between the membranes (pleural effusion). Pleural effusion itself is benign and doesn't increase your risk of asbestosis or malignant mesothelioma.
  • Other cancer. Prolonged exposure — 20 years or more — to asbestos can also lead to malignant mesothelioma. Diagnosis and treatment of this cancer is often difficult. Malignant mesothelioma may occur even many years after exposure has stopped.
How is asbestosis treated?

Patients with asbestosis, like others with chronic lung disease, are at a higher risk of serious infection, low oxygen levels in the blood, and heart failure. These patients also may not recover as quickly from viral and bacterial infections. In addition, they may be at increased risk for certain fungal and unusual infections that take advantage of diseased or scarred lung tissue. The medical management of these patients should focus special attention on preventing and rapidly treating these infections. Flu and pneumococcal vaccinations are a part of routine care for these patients. There is, however, no treatment or cure for asbestosis. In particular, steroid and immune-based therapies have not been shown to benefit these patients.

There's no treatment to reverse the effects of asbestos on the alveoli. Treatment focuses on preventing progression of the disease and relieving symptoms. The most important factor in keeping the condition from worsening is to eliminate exposure to asbestos. For most people, scarring of lung tissue doesn't begin or progress once exposure has ended.

The following may be components of asbestosis treatment:
  • Smoking cessation. If you smoke, it's important to stop, particularly because of the extremely heightened risk of lung cancer. In addition, smoking may cause emphysema, which further reduces your lung reserves.
  • Vaccinations. Because of your impaired lung condition, treat a cold or a bout of the flu promptly to avoid complications. Your doctor may advise you to receive flu and pneumonia vaccines.
  • Medications. The complication of pulmonary hypertension is often treated with medications to expand or relax blood vessels, and blood-thinning medications to prevent blood clots from forming and obstructing narrowed vessels.
To ease difficulty breathing, your doctor may prescribe supplemental oxygen or drain fluid from around your lungs, if necessary. Occasionally, severe cases of asbestosis may be treated with lung transplantation.

© 1998-2008 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research. Terms of Use.

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Asbestos Disease | Types of Asbestos Disease

Asbestosis

scaring of the lung tissue

Mesothelioma nodular cancer of the plural lining of the lung
Lung Cancer

Note: smoking greatly increases risk - 50 to 90 times


The most common forms of asbestos disease are pleural plaques, asbestosis, lung cancer, and mesothelioma.

Asbestosis

Asbestosis is a disease which is characterized by pulmonary fibrosis, a progressive scarring of the lungs caused by the accumulation of asbestos fibers. Asbestosis is associated exclusively with chronic, occupational exposure. The build up of scar tissue interferes with oxygen uptake through the lungs and can lead to respiratory and heart failure. Often, asbestosis is a progressive disease, even in the absence of continued exposure. Symptoms include shortness of breath, cough, fatigue, and vague feelings of sickness. When the fibrosis worsens, shortness of breath occurs even at rest.

Pleural Plaques

Pleural plaques and pleural calcification are markers of exposure and may develop 10 to 20 years after initial exposure. Plaques are opaque patches visible on chest x-rays that consist of dense strands of connective tissue surrounded by cells. All commercial types of asbestos induce plaques. Plaques can occur even when fibrosis is absent and do not seem to reflect the severity of pulmonary disease.

Lung Cancer

Of all the diseases related to asbestos exposure, lung cancer has been responsible for over half of the excess deaths resulting from occupational exposure. Although tissues and cells react to the presence of asbestos immediately, detectable symptoms take years, or more often decades, to manifest themselves. Asbestos-induced lung cancer may not show up on x-rays for twenty years or more after the exposure began. This delay between exposure and onset is referred to as the "latency period". Even in cases of prolonged heavy exposure, abnormalities commonly appear on x-rays only after ten or more years following exposure.

Mesothelioma

Mesothelioma is rare or nonexistent in non-asbestos exposed populations but is becoming more common among asbestos-exposed individuals.

Mesothelioma is a cancer of the lining of the lungs and not a cancer that occurs inside the lung. Mesothelioma causes the cells of the mesothelium to become abnormal and infinitely reproduce.

A normal mesothelium cell (or any cell for that matter) can only reproduce a certain amount of times. This keeps certain cells from invading other cells. Cancer occurs when those cells become mutated and their limits are removed, allowing them to reproduce uncontrollably. These abnormal cells then form a lump that is known as a tumor. In a benign tumor the abnormal cells do not spread into surrounding areas, but malignant tumors do have the ability to spread. If the tumor is left untreated then it may spread and destroy the neighboring tissue. Sometimes cells can even break off the original tumor and spread to other organs and tissue through the bloodstream or the lympathic system. The lympathic system is part of the immune system. It is a complex system that includes the bone marrow, the thymus and the spleen, and lymph nodes throughout the body that are connected by a network of lympathic vessels. When the cancer cells reach a new site they may continue to divide and form a new tumor, which is referred to as a secondary tumor or a metastasis.

Mesothelial cells line the chest cavity, the abdominal cavity, and the cavity around the heart. They also cover the outer surface of most internal organs. The tissue that is formed by these mesothelial cells is called mesothelium. Mesothelium helps protect the organs by producing a lubricating fluid that lets organs move around. This fluid makes it easier for the lungs to expand and move around inside the chest during breathing. The mesothelium in the chest is called the pleura and the mesothelium around the abdomen is known as the peritoneum. The mesothelium around the heart (or the pericardial cavity, a sac like space around the heart) is called the pericardium.

The asbestos disease mesothelioma has a long latency period, where it is present but not evident or active. The disease can lie dormant for ten to sixty years after being exposed to asbestos. Because of this, it is often hard to determine the cause of mesothelioma.

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Monday, September 22, 2008

Asbestos Exposure - How is Expose and Affect for Health?

What is Asbestos?



Asbestos is the common name for any variety of silicate materials that are fibrous in structure and are more resistant to acid and fire than other materials. It has two forms, serpentine and amphibole, and is made of impure magnesium silicate. Asbestos is used for thermal insulation, fire proofing, electrical insulation, building materials, brake linings and has been used in numerous industries.

There are six different minerals commercially available that can make up "asbestos exposure", including:

1. chrysotile,or white asbestos;
2. amosite,which usually has brown fibers;
3. crocidolite,or blue asbestos;
4. tremolite,
5. anthophyllite, which usually has gray fibers
6. actinolite.

Of these differerence minerals, chrysotile and amosite are most often used.

Asbestos is a potent carcinogen, that is, a cancer-causing substance, and is a serious health hazard. It is the known cause of pleural plaques, asbestosis, mesothelioma, and causes cancers of the lung, esophagus, and colon. Diseases caused by asbestos have a long latency period, usually taking ten to forty years before showing any symptoms of the disease. This is especially apparent today, when people who worked with installing asbestos as insulation and other materials in the 1970s are just now coming to realize that they are developing cancer at alarming rates.


Asbestos Exposure in My Home

The U.S. Environmental Protection Agency provides information in its website about possible locations in the home where asbestos hazards may be found9:

1. Some roofing and siding shingles are made of asbestos cement.
2. Houses built between 1930 and 1950 may have asbestos as insulation.
3. Asbestos may be present in textured paint and patching compounds used on wall and ceiling joints. Their use was banned in 1977.
4. Artificial ashes and embers sold for use in gas-fired fireplaces may contain asbestos.
5. Older products such as stove-top pads may have some asbestos compounds.
6. Walls and floors around wood burning stoves may be protected with asbestos paper, millboard, or cement sheets.
7. Asbestos is found in some vinyl floor tiles and the backing on vinyl sheet flooring and adhesives.
8. Hot water and steam pipes in older houses may be coated with an asbestos material or covered with an asbestos blanket or tape.
9. Oil and coal furnaces and door gaskets may have asbestos insulation.




How might I be exposed to asbestos?

We are all exposed to low levels of asbestos in the air we breathe. These levels range from 0.00001 to 0.0001 fibers per milliliter of air and generally are highest in cities and industrial areas.

People working in industries that make or use asbestos products or who are involved in asbestos mining may be exposed to high levels of asbestos. People living near these industries may also be exposed to high levels of asbestos in air.

Asbestos fibers may be released into the air by the disturbance of asbestos-containing material during product use, demolition work, building or home maintenance, repair, and remodeling. In general, exposure may occur only when the asbestos-containing material is disturbed in some way to release particles and fibers into the air.

Drinking water may contain asbestos from natural sources or from asbestos-containing cement pipes.
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How can asbestos affect my health?

Asbestos mainly affects the lungs and the membrane that surrounds the lungs. Breathing high levels of asbestos fibers for a long time may result in scar-like tissue in the lungs and in the pleural membrane (lining) that surrounds the lung. This disease is called asbestosis and is usually found in workers exposed to asbestos, but not in the general public. People with asbestosis have difficulty breathing, often a cough, and in severe cases heart enlargement. Asbestosis is a serious disease and can eventually lead to disability and death.

Breathing lower levels of asbestos may result in changes called plaques in the pleural membranes. Pleural plaques can occur in workers and sometimes in people living in areas with high environmental levels of asbestos. Effects on breathing from pleural plaques alone are not usually serious, but higher exposure can lead to a thickening of the pleural membrane that may restrict breathing.
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How likely is asbestos exposure to cause cancer?

The Department of Health and Human Services (DHHS), the World Health Organization (WHO), and the EPA have determined that asbestos is a human carcinogen.

It is known that breathing asbestos can increase the risk of cancer in people. There are two types of cancer caused by exposure to asbestos: lung cancer and mesothelioma. Mesothelioma is a cancer of the thin lining surrounding the lung (pleural membrane) or abdominal cavity (the peritoneum). Cancer from asbestos does not develop immediately, but shows up after a number of years. Studies of workers also suggest that breathing asbestos can increase chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, and kidneys), but this is less certain. Early identification and treatment of any cancer can increase an individual's quality of life and survival.

Cigarette smoke and asbestos together significantly increase your chances of getting lung cancer. Therefore, if you have been exposed to asbestos you should stop smoking. This may be the most important action that you can take to improve your health and decrease your risk of cancer.

Is there a medical test to show whether I've been exposed to asbestos?

Low levels of asbestos fibers can be measured in urine, feces, mucus, or lung washings of the general public. Higher than average levels of asbestos fibers in tissue can confirm exposure but not determine whether you will experience any health effects.

A thorough history, physical exam, and diagnostic tests are needed to evaluate asbestos-related disease. Chest x-rays are the best screening tool to identify lung changes resulting from asbestos exposure. Lung function tests and CAT scans also assist in the diagnosis of asbestos-related disease.

References
Agency for Toxic Substances and Disease Registry (ATSDR). 2001. Toxicological Profile for Asbestos. Update. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

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