Asbestos was used commercially in North America as early as the late 1800s, but its use increased dramatically during the World War II era when shipyards produced massive numbers of ships for the war effort. Since that time, asbestos-containing products were used by the construction and building trades, the automotive industry and the manufacturing industry. All told, more than 5,000 products contained asbestos.

For more than 50 years, products containing asbestos remained unregulated, and the manufacturers of those products continued to prosper, knowing full well that many of the millions of workers who came into contact with their products would ultimately suffer as the result of their actions. Finally, in the late 1970s, the Consumer Products Safety Commission banned the use of asbestos in wallboard patching compounds and artificial ash for gas fireplaces because the fiber could easily be released during use. In 1989, the Environmental Protection Agency banned all new use of asbestos, but uses established prior to that time were still allowed. Although awareness of the dangers of asbestos and public concern over the issue have led to a decline in domestic consumption over the years, a total ban on asbestos has not come to fruition. Asbestos is still imported, still used and still dangerous.

Although it is suggested that the number of mesothelioma cases in the U.S. has reached its peak and has begun to drop, a forecast released by the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program (SEER), in April, 2003, projected the total number of American male mesothelioma cases from 2003-2054 to be approximately 71,000. This number, however, does not take into consideration events such as the World Trade Center disaster on September 11, 2001, when millions of New Yorkers were potentially exposed to air filled with carcinogenic asbestos particles. The incidence of mesothelioma cases by state and county are shown in these tables. When the latency period for asbestos disease is factored in, cases of mesothelioma will continue to be diagnosed for years to come. See our page on mesothelioma risk factors.

Does exposure to asbestos always cause mesothelioma? No, less than 10% of people with a history of heavy asbestos exposure develop mesothelioma. But 80% of those with pleural mesothelioma have a demonstrated history of asbestos exposure. There is no doubt that exposure to asbestos fibers increases the risk of mesothelioma. This is why you should mention any history of asbestos exposure to a doctor attempting a diagnosis.

Questions Regarding the Risk Level of Asbestos Exposure

Research data has shown that there is a definite correlation between exposure to asbestos particles and asbestos-related diseases, especially for those that are exposed to the fibers in their workplace. Even though data shows a connection between these factors, there is ongoing debate as to just “how much of a risk is present” in environments where asbestos fibers can be found.

Questions have been raised because some of the factors relating to asbestos exposure can vary considerably sometimes making it difficult to define absolute asbestos-related exposure relationships. Some of these variables include asbestos fiber sizes and types, the type of asbestos-related disease, and the duration and level of exposure to the fibers.

Even with the uncertainty, progress has been made in regards to these variables and their effects on human health over the last 25 years. This information may present an issue for regulating authorities and agencies because it may require a deviation from their current opinions on asbestos exposure and its effects on health.

Differing Characteristics of Asbestos Fibers as They Relate to Health Conditions

People that have inhaled asbestos fibers have been shown to develop health conditions such as asbestosis, mesothelioma, and lung cancer. There is confusion as to which asbestos types pose a greater risk of asbestos-related disease and to what degree. Additionally, there are questions regarding which exposure conditions present this risk.

One problem in regards to establishing clear-cut asbestos-related factors may be the use of the term “asbestos”, as a catch-all or general term used to represent various asbestos fibers that have different toxic characteristics and tendencies that cause related diseases.

More than 150 studies of asbestos particles has been used to determine the relationship between incidences of asbestos disease and suspected factors; however, this research has had little value in determining level of risk due to limited data on levels of human exposure, fiber types, and other possible contributing factors (i.e. smoking or other lifestyle practices). Other obstacles that contribute to the limitations of this research include the use of many different fiber types or the lack of defining fiber types used in studies.

Asbestos from natural geologic deposits is known as “Naturally Occurring Asbestos” (NOA). Health risks associated with exposure to NOA are not yet fully understood, and current US federal regulations do not address exposure from NOA. Many populated areas are in proximity to shallow, natural deposits which occur in 50 of 58 California counties and in 19 other U.S. states. In one study, data was collected from 3,000 mesothelioma patients in California and 890 men with prostate cancer, a malignancy not known to be related to asbestos. The study found a correlation between the incidence of mesotheliomas and the distance a patient lived from known deposits of rock likely to include asbestos, the correlation was not present when the incidence of prostate cancer was compared with the same distances. According to the study, risk of mesothelioma declined by 6 percent for every 10 kilometers that an individual had lived away from a likely asbestos source.^[22]

Portions of El Dorado County, California are known to contain natural asbestos formations near the surface.^[23][22] The USGS studied amphiboles in rock and soil in the area in response to an EPA sampling study and subsequent criticism of the EPA study. The study found that many amphibole particles in the area meet the counting rule criteria used by the EPA for chemical and morphological limits, but do not meet morphological requirements for commercial-grade-asbestos. The executive summary pointed out that even particles that do not meet requirements for commercial-grade-asbestos may be a health threat and suggested a collaborative research effort to assess health risks associated with “Naturally Occurring Asbestos.”^[24]

Large portions of Fairfax County, Virginia were also found to be underlain with tremolite. The county monitored air quality at construction sites, controlled soil taken from affected areas, and required freshly developed sites to lay 6 inches (150 mm) of clean, stable material over the ground.^[22]

Most people who develop mesothelioma have worked on jobs where they inhaled asbestos particles, or they have been exposed to asbestos dust and fiber in other ways. It has also been suggested that washing the clothes of a family member who worked with asbestos can put a person at risk for developing mesothelioma.^[2] Unlike lung cancer, there is no association between mesothelioma and smoking, but smoking greatly increases risk of other asbestos-induced cancer.^[3] Compensation via asbestos funds or lawsuits is an important issue in mesothelioma (see asbestos and the law).

The symptoms of mesothelioma include shortness of breath due to pleural effusion (fluid between the lung and the chest wall) or chest wall pain, and general symptoms such as weight loss. The diagnosis may be suspected with chest X-ray and CT scan, and is confirmed with a biopsy (tissue sample) and microscopic examination. A thoracoscopy (inserting a tube with a camera into the chest) can be used to take biopsies. It allows the introduction of substances such as talc to obliterate the pleural space (called pleurodesis), which prevents more fluid from accumulating and pressing on the lung. Despite treatment with chemotherapy, radiation therapy or sometimes surgery, the disease carries a poor prognosis. Research about screening tests for the early detection of mesothelioma is ongoing.

Signs and symptoms

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
• Fatigue or anemia
• Wheezing, hoarseness, or cough
• Blood in the sputum (fluid) coughed up (hemoptysis)

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.