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What is Mesothelioma.

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Mesothelioma is a form of cancer that is almost always caused by previous exposure to asbestos. In this disease, malignant cells develop in the mesothelium, a protective lining that covers most of the body's internal organs. Its most common site is the pleura (outer lining of the lungs and chest cavity), but it may also occur in the peritoneum (the lining of the abdominal cavity) or the pericardium (a sac that surrounds the heart).

Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles, or have been exposed to asbestos dust and fibre in other ways, such as by washing the clothes of a family member who worked with asbestos, or by home renovation using asbestos cement products. There is no association between mesothelioma and smoking


Signs and the Syptoms

Symptoms of mesothelioma may not appear until 20 to 50 years after exposure to asbestos. Shortness of breath, cough, and pain in the chest due to an accumulation of fluid in the pleural space are often symptoms of pleural mesothelioma.



Symptoms of peritoneal mesothelioma include weight loss and cachexia, abdominal swelling and pain due to ascites (a buildup of fluid in the abdominal cavity). Other symptoms of peritoneal mesothelioma may include bowel obstruction, blood clotting abnormalities, anemia, and fever. If the cancer has spread beyond the mesothelium to other parts of the body, symptoms may include pain, trouble swallowing, or swelling of the neck or face.

These symptoms may be caused by mesothelioma or by other, less serious conditions.

Mesothelioma that affects the pleura can cause these signs and symptoms:

+ chest wall pain
+ pleural effusion, or fluid surrounding the lung
+ shortness of breath
+ wheezing, hoarseness, or cough

In severe cases, the person may have many tumor masses. The individual may develop a pneumothorax, or collapse of the lung. The disease may metastasize, or spread, to other parts of the body.

Tumors that affect the abdominal cavity often do not cause symptoms until they are at a late stage. Symptoms include:

+ abdominal pain
+ ascites, or an abnormal buildup of fluid in the abdomen
+ a mass in the abdomen
+ problems with bowel function
+ weight loss

In severe cases of the disease, the following signs and symptoms may be present:

+ blood clots in the veins, which may cause thrombophlebitis
+ disseminated intravascular coagulation, a disorder causing severe bleeding in many body organs
+ jaundice, or yellowing of the eyes and skin
+ low blood sugar level
+ pleural effusion
+ pulmonary emboli, or blood clots in the arteries of the lungs
+ severe ascites

A mesothelioma does not usually spread to the bone, brain, or adrenal glands. Pleural tumors are usually found only on one side of the lungs

What is Asbestos and why is it so harmful.

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Asbestos (a misapplication of Latin: asbestos "quicklime" from Greek ἄσβεστος: a, "not" and sbestos, "extinguishable") describes any of a group of minerals that can be fibrous, many of which are metamorphic and are hydrous magnesium silicates. These minerals, together with their occurrences, uses, and associated hazards, have been discussed in detail by Guthrie and Mossman.
The name is derived for its historical use in lamp wicks; the resistance of asbestos to fire has long been exploited for a variety of purposes. Asbestos was used in fabrics such as Egyptian burial cloths and Charlemagne's tablecloth (which according to legend, he threw in a fire to clean). Asbestos occurs naturally in many forms it is mined from metamorphic rocks.

When asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement or woven into fabric or mats. Asbestos is used in brake shoes and gaskets for its heat resistance, and in the past was used on electric oven and hotplate wiring for its electrical insulation at elevated temperature, and in buildings for its flame-retardant and insulating properties, tensile strength, flexibility, and resistance to chemicals.




Low levels of asbestos are in the air we breathe and some of the water we drink, including water from natural sources. Studies have shown that members of the general (nonoccupationally exposed) population have tens of thousands to hundreds of thousands of asbestos fibers in each gram of dry lung tissue, which translates into millions of fibers and tens of thousands of asbestos bodies in every person's lungs.

The EPA has proposed a concentration limit of 7 million fibers per liter of drinking water for long fibers (lengths greater than or equal to 5 µm). OSHA (Occupational Safety and Health Administration) has set limits of 100,000 fibers with lengths greater than or equal to 5 µm per cubic meter of workplace air for 8-hour shifts and 40-hour work weeks.

Most respirable asbestos fibers are invisible to the unaided human eye because their size is about 3.0-20.0 µm in length and can be as thin as 0.01 µm. Human hair ranges in size from 17 to 181 µm in width. Fibers ultimately form because when these minerals originally cooled and crystallized, they formed by the polymeric molecules lining up parallel with each other and forming oriented crystal lattices. These crystals thus have three cleavage planes, just as other minerals and gemstones have. But in their case, there are two cleavage planes that are much weaker than the third direction. When sufficient force is applied, they tend to break along their weakest directions, resulting in a linear fragmentation pattern and hence a fibrous form. This fracture process can keep occurring and one larger asbestos fiber can ultimately become the source of hundreds of much thinner and smaller fibers.

As asbestos fibers get smaller and lighter, they more easily become airborne and human respiratory exposures can result. Fibers will eventually settle but may be re-suspended by air currents or other movement.

Friability of an asbestos containing product means that it is so soft and weak in structure that it can be broken with simple finger crushing pressure. Friable materials are of the most initial concern due to their ease of damage. The forces or conditions of usage that come into intimate contact with most non-friable asbestos containing materials are substantially higher than finger pressure. Non-friable asbestos products can release substantial quantities of asbestos fibers into their environments as well.

As early as 1898 the Chief Inspector of Factories of the United Kingdom reported to Parliament in his Annual Report about the "evil effects of asbestos dust". He reported the "sharp, glass like nature of the particles" when allowed to remain in the air in any quantity, "have been found to be injurious, as might have been expected" (Report of the Select Committee 1994). In 1906 a British Parliamentary Commission confirmed the first cases of asbestos deaths in factories in Britain and recommended better ventilation and other safety measures. In 1918 a US insurance company produced a study showing premature deaths in the asbestos industry in the United States. In 1926 the Massachusetts Industrial Accidents Board processed the first successful compensation claim by a sick asbestos worker.[citation needed] Many American injuries from asbestos exposure came from shipbuilders working during World War II.

The problem with asbestos arises when the fibers become airborne and are inhaled. Because of the size of the fibers, the lungs cannot expel them. [Casarrett & Doull's Toxicology (2001), pp 520-522]

Asbestosis – A lung disease first found in naval shipyard workers, asbestosis is a scarring of the lung tissue from an acid produced by the body's attempt to dissolve the fibers. The scarring may eventually become so severe that the lungs can no longer function. The latency period (the time it takes for the disease to develop) is often 10-20 years.

Mesothelioma – A cancer of the mesothelial lining of the lungs and the chest cavity, the peritoneum (abdominal cavity) or the pericardium (a sac surrounding the heart). It is believed that mesothelioma is caused by generation of reactive oxygen species (ROS) by the asbestos fibers. There is also some evidence to suggest that simian virus 40 (SV40) works together with asbestos in the development of malignant mesothelioma. Asbestos exposure is linked to at least 50% of patients developing malignant mesothelioma. Malignant mesothelioma has a peak incidence 35-45 years after asbestos exposure. Median survival for patients with malignant mesothelioma is 11 months. Asbestos has a synergistic effect with tobacco smoking in the causation of pleural mesothelioma.

Cancer – Lung cancer has been linked to asbestos. Asbestos exposure alone can cause lung cancer, but asbestos exposure and tobacco smoking has a synergistic effect, greatly increasing the chances of contracting lung cancer. Cancer of the larynx has been linked to asbestos. Some studies suggest that asbestos exposure is linked to a slightly increased risk of stomach, pharyngeal, and colorectal cancer.

EWG Action Fund estimates that in the United States, about 9,900 people die each year of asbestos-related diseases, such as mesothelioma, asbestosis, lung cancer, and gastrointestinal cancer.