Kazan, McClain, Satterley, Lyons, Greenwood & Oberman, A Professional Law Corporation

Asbestos Diseases


What happens when we breathe?

When we take a deep breath, the air goes down the wind-pipe (or trachea) into the middle of the chest. There the trachea divides into two, then four, then eight - and finally, hundreds of thousands of little airways (or bronchi and bronchioles) in each lung. At the end of each airway is a tiny sac (or alveolus.) Healthy lungs have hundreds of millions of these sacs (or alveoli.)


An upside-down oak tree provides a good example: The wind-pipe is like the large trunk which divides countless times into branches (airways) and twigs (small airways), until at the end of every twig there is a leaf (alveolus). As the wind blows, the leaves move.


Similarly, the air we inhale moves all the way through the lungs to the alveoli. The oxygen in that deep breath is transported through the walls of the alveoli into the red blood cells in the blood vessels (capillaries) that surround each alveolus.


The heart then pumps the oxygen-rich blood through the body and we are able to do things like run up a hill, throw a ball, or surf the web.


One of the by-products of all this web-surfing and ball-throwing, is the build-up of 'exhaust fumes' (carbon dioxide) in the body's cells. Red blood cells pick up the carbon dioxide in place of the oxygen they deliver.


Thus, there are two processes at work as we breathe in and breathe out. Blood vessels transport blood that is rich in carbon dioxide and poor in oxygen to the alveoli. And, in the reverse process, the carbon dioxide goes out through the walls of the alveoli, into the airways, and, as we breathe out, back up the trachea.


The lungs expand and contract as we breathe in and out, whereas our ribs are fairly immobile. The pleura, or lining around the outside of the lungs and inside of the ribs, has some lubricating fluid. It allows the lungs and ribs to slide over each other comfortably. It is easy to imagine that, if the pleura is damaged or inflamed, every breath becomes very painful.


However, when we are healthy, breathing is easy - so easy we don't even think about it.


What is asbestos?

Asbestos is the name for a group of naturally-occurring minerals that can be separated into strong, very fine fibers. These fibers are extremely durable, and heat and fire resistant. Because of these qualities, asbestos has been used in thousands of industrial, construction and consumer products. The major fiber types used commercially are chrysotile (mostly from Canada,) amosite (from southern Africa,) and crocidolite (from southern Africa and Australia.)


Unless the fibers are completely encapsulated, they tend to break down into a microscopic dust. A single fiber of asbestos magnified 1,000 times looks slightly larger than a strand of human hair. Because of their size and shape, asbestos fibers can remain suspended in the air for long periods of time, and therefore they can be inhaled.


When asbestos fibers are inhaled (or swallowed) they can easily penetrate the tissues of the body and, because of their durability, remain in the body for many years.


What happens when asbestos is in the air we breathe?

Asbestos fibers enter the body in the air we breathe. Most of the asbestos fibers we breathe - like other dust particles - are stopped long before they enter the small airways of the lungs. For example, when we enter a dusty room or sprinkle powder, we sometimes choke. We literally cough up the mucus that contains most of the irritating substances. However, because asbestos fibers are so small and thin, many of them pass all the way down to the small airways and alveoli (or air sacs.)


Once the fibers are inside the lungs, the body's defense mechanisms try to break them down and remove them. Despite these attempts, many fibers remain in the body and are potential disease-causing agents. Each fiber is a foreign body, rather like a splinter in a finger. Inflammations develop as the body tries to neutralize, break down or move the sharp, irritating fibers. These processes lead to the development of the various kinds of asbestos-caused diseases.


The body's defenses often coat these fibers with a layer of protein and they are then called 'asbestos bodies.' If a piece of lung tissue is stained with an iron stain these asbestos bodies become readily visible under a microscope. Finding enough of these asbestos bodies in lung tissue proves prior occupational exposure to asbestos, but it does not in itself prove that the person has an asbestos disease. (Also, not finding asbestos bodies does not prove that there was no prior exposure to asbestos.)


Click on A, B and C to see three microscopic slides of asbestos fibers lodged in the lungs.


Although all of the different kinds of asbestos fibers can be inhaled and become lodged in the lungs, some fibers (amphiboles, like amosite and crocidolite) seem to accumulate to a greater extent than others (such as chrysotile.) This might be because some chrysotile fibers, being long and curly, get stuck higher up in the lungs rather than transported all the way into the small airways. Or it might be because chrysotile fibers, being fragile and unstable, break up in the body within a few months and are transported away from the lungs into the pleura or lymph system.


Once fibers are inside the body, they can move around. How this happens is not fully understood. It might be because they are thin and sharp. The fibers can move from the lungs into the pleura and into the lymph nodes, and this means that they can move into other parts of the body.


Finally, asbestos can be swallowed (ingested) as well as inhaled. For example, when mucus and sputum that contain a lot of fibers are swallowed, some of those fibers can stick in the intestinal tract and from there they can move into the lining of the abdomen (peritoneum.)


What are asbestos-related diseases?

There are several different kinds of diseases that are related to previous exposure to asbestos fibers, and they can be categorized in various ways:


Some are malignant (or cancerous), such as mesothelioma and lung cancer. Others are benign (non-malignant or non-cancerous), such as asbestosis, pleural plaques, diffuse pleural fibrosis, and benign pleural effusions.


Some are increasingly and severely disabling, often leading to death, like mesothelioma, asbestosis and lung cancer; and others are less so, such as pleural plaques and thickening, which rarely produce symptoms or disability.


Some are very clearly and directly attributable to exposure to asbestos, such as asbestosis and mesothelioma. For others, such as gastro-intestinal tract cancers, the causal connection to asbestos exposure is one that appears probable but has not yet been proven with certainty.


The diseases for which asbestos exposure is a generally accepted cause are mesothelioma, asbestosis, small airway fibrosis, scarring, pleural plaques, pleural fibrosis, pleural effusion, and many lung cancers. Diseases for which asbestos exposure is not at this time generally accepted as the cause, include cancers of the kidney, GI tract and ovary.


Each of these asbestos-related diseases can only be diagnosed through medical examinations and tests. If you were exposed to asbestos it does not mean that you therefore must have, or will have, an asbestos-caused disease. But it does mean that you should:  

  • be vigilant about your health,
  • receive regular medical care and check-ups, and
  • tell your doctor about your asbestos exposure.

SV 40 - Does this virus cause mesothelioma?

In early 1999 a debate about a virus called SV 40 and its presence in certain tumors, briefly garnered media coverage.

Simian virus 40 (or SV 40) is a virus of monkey origin. It was a contaminant of polio vaccines in the late 1950's and early 1960's because the vaccines were grown on monkey kidneys and some of these monkeys were carriers of SV 40.


SV 40 has been identified in mesothelioma tumors as well as in brain and bone cancers, which led to theories about a possible relationship between exposure to the virus and later development of mesotheliomas and other cancers.


For example, in one study hamsters were injected intra-pleurally with a type of SV 40. Over 50% developed mesothelioma and all of them developed tumors. (American Journal of Pathology: 142:5 1524-1533 by Cicala, et al.)


However, a recent study (Thorax: 1999;54 (60-61) by Mulatero, Surentheran, et al.) of stored mesothelioma tumor samples did not support the hypothesis that SV 40 was related to increasing incidences of mesothelioma. And birth cohort studies in both the U.S. and Sweden show no increase in risk of cancer associated with exposure to the SV 40 contaminated polio vaccine.


Yet other studies suggest that the presence of SV 40 might lead to the development of new therapies for cancer. (Journal of the National Cancer Institute: 91(2):169-75 1999)


As our knowledge of genetics and tumor biology grows, we will develop new treatments for mesothelioma, but at the moment the possible role of SV 40 in either triggering or treating mesothelioma is far from clear.


Regarding contamination of polio vaccines, the World Health Organization issued an informative statement.


Lung cancer

Lung cancer refers to any type of malignant tumor that originates in the lung itself (unlike mesothelioma, which is in the pleural lining around the lung.)


Some lung cancers are caused by asbestos exposure, but the nature of this relationship is not yet fully understood. What is certain is that the risk of developing lung cancer is much greater for those with significant occupational exposure to asbestos, as compared to the general population who have background exposure (see 'Asbestos Exposure & Your Job') Also, the greater the exposure, the greater the risk.


There is also a long incubation (latency) period between asbestos exposure and the development of lung cancer. In fact, incidence of cancer appears to peak as long as thirty years after first exposure.


Adding to the complexity of understanding the relationship between lung cancer and asbestos exposure is the issue of smoking. There is a synergistic relationship between asbestos exposure and smoking. What this means is that although workers who have been exposed to asbestos have a higher risk of developing lung cancer, it is also well known that smokers have a higher risk of developing lung cancer; but the cancer risk of workers who were exposed to asbestos and who smoked is not simply the sum of these two separate risks. Rather, these risks are multiplied. The combined cancer risk is therefore very much higher - as high as 50 to 90 times the risk faced by the general population.


The most important conclusion to be drawn from this, for anyone who has been exposed to asbestos and who smokes, is to quit smoking now.



Asbestosis is, as its name suggests, caused by inhalation of asbestos fibers. It is not a cancerous lung disease.

The underlying disease process of asbestosis is not yet fully understood, but it appears that asbestos fibers in the lungs cause irritation and inflammation. The body attempts to neutralize these foreign fibers in various complex ways, and some or all of these processes lead to further inflammation and cell damage. Eventually a fibrosis or scar tissue develops in the interstitial spaces around the small airways and alveoli. This thickening and scarring prevents oxygen and carbon dioxide from traveling between the alveoli and the blood cells, so breathing becomes much less efficient.


Asbestosis often exists without any symptoms, and is then detected only by x-ray findings. However, the symptoms of asbestosis typically include shortness of breath and coughing. As the disease progresses, the symptoms can worsen. It can be a progressive disease, meaning that it continues to progress even after exposure to asbestos has stopped. In unusual cases it can be fatal.


The scarring and thickening can be seen on x-rays and CT scans. Also, if it reduces the functioning of the lungs, asbestosis can be detected by a breathing or pulmonary function test (PFT.)


Diagnosis can be made only when there is a history of asbestos exposure and positive results from a clinical exam, chest x-rays, CT scans, and/or a pulmonary function test (PFT.) It can also be conclusively identified through a biopsy; click on A, B and C to see three microscopic slides of asbestos fibers lodged in the lungs.


Asbestosis affects both lungs (it is bilateral) and, although it is mainly in the lower fields of the lungs, it is usually widespread (diffuse.)


Serious asbestosis is usually caused by heavy exposure to asbestos, such as sustained exposure over a period of years (e.g. a longtime worker at an asbestos textile plant) and/or intense exposure during a shorter period (e.g. a worker in the boiler and engine rooms of ships under construction in the Second World War.)


This does not mean that everyone who was heavily exposed to asbestos gets asbestosis, only that everyone who gets asbestosis was exposed to large quantities of asbestos fibers.


The specific type of asbestos fiber to which the worker was exposed does not seem to be significant in the development of asbestosis.


At the moment there is no cure or effective treatment for asbestosis. People with asbestosis are also at high risk of developing lung cancer or mesothelioma.


Other asbestos-related diseases

The causal connection between exposure to asbestos fibers and development of gastro-intestinal tract cancers appears probable, but has not yet been proven with certainty. The diseases for which asbestos exposure is a generally accepted cause, are mesothelioma, asbestosis, small airway fibrosis, pleural plaques, pleural fibrosis, pleural effusions, and many lung cancers in association with asbestosis.


At this time asbestos exposure is not generally accepted as the cause of cancers of the pancreas, kidney, stomach, colon, esophagus or ovary.



Smoking tobacco has not been directly linked to the development of mesothelioma or asbestosis, but it is linked to lung cancer. There is also a synergistic relationship between smoking and exposure to asbestos, and the development of lung cancer.


Workers who were exposed to asbestos and who smoked or were exposed to second-hand smoke run a risk of getting lung cancer that is 50 to 90 times higher than that of the general population. According to the 1985 Surgeon General's report, The Health Consequences of Smoking: Cancer and Chronic Lung Disease in the Workplace, asbestos workers who smoked a pack or more a day are eighty-seven times more likely to die of lung cancer than the general nonsmoking public. This risk is eight times higher than other smokers and seventeen times higher than asbestos workers who did not smoke.


The Firm has been and is active in the political and legal process of ensuring that a settlement with the tobacco industry includes adequate provision for the victims of asbestos and tobacco caused disease. For instance, Steven Kazan testified before Congress during the 1998 debate about Big Tobacco.


Further information

A number of websites contain information about different types of cancers, asbestos-related diseases, and treatment options, among them:

National Cancer Institute

University of Pennsylvania/OncoLink

American Cancer Society

The Daily Apple

Medicine Online

At your local library or bookstore you might want to look at the following titles about cancer treatments and living with cancer:


  • Dollinger Malin, M.D., ed. - Everyone's Guide to Cancer Therapy, Andrews & McMeel, 1998, 3rd edition
  • Ernest H. Rosenbaum, M.D. and Isadora Rosenbaum - Cancer Supportive Care: A Comprehensive Guide for Patients and their Families, Somerville House, 1998
  • Ernest H. Rosenbaum, M.D. and Isadora Rosenbaum - Inner Fire: Your Will to Live; Plexus Publishing, 1999
  • Laura Landro - Survivor: Taking Control of Your Fight Against Cancer; Simon & Schuster, 1998. You can listen to an interview with the author that aired on the NPR program 'Fresh Air': Click Here (To listen you need to have RealAudio installed on your computer or to download it; click on the above link and follow the instructions.)

Most of our practice is in asbestos litigation, so we have developed extensive knowledge about asbestos-related disease in particular and expertise in this area of the law. Please feel free to contact us or to review other parts of our website to find out more information about our office.



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