Asbestos - The predominant factor that causes mesothelioma is by exposure to asbestos fibers.   Asbestos is an insulating material that is composed of magnesium-silicate mineral fibers. It was used extensively for many years because of some desirable properties such as its resistance to melting and resistance to burning. Asbestos has been used extensively in many industrial products such as cement, roof shingles, flooring products, insulation and textiles.  Researchers have identified a strong link between mesothelioma and exposure to asbestos, and so nowadays the material is  less widely used. It is not however totally banned. Prior to the discovery of the strong correlation (relationship) between mesothelioma and asbestos, millions of individuals have had prolonged exposure to this harmful substance.

During the manufacturing process tiny asbestos particles may float in the air, where they may be inhaled. These inhaled asbestos fibers may eventually be embedded in the mesothelium where they may originate into mesothelioma. These particles not only can cause mesothelioma but also other serious health problems such as lung cancer, asbestosis, and other cancers in general. The risk of developing mesothelioma and other asbestos-related diseases increases with heavier exposure to asbestos and longer exposure to it.  However it can be said that individuals have developed mesothelioma by a brief exposure to asbestos while others that have been heavily exposed to it have not developed mesothelioma at all. Although mesothelioma generally results from occupational exposure there are situations of exposure to asbestos from the environment that may have caused the disease. 

Families may be located near former asbestos production facilities, may also be at risk. The demolition of structures that contain asbestos can contaminate nearby families. The family members of asbestos workers may be exposed to asbestos dust that has been brought home on the clothes and hair of asbestos workers. This can cause family members to develop mesothelioma years later. Because of this it is important that asbestos workers take appropriate precautions. For example they may wash themselves and change their clothes on the place of work before going to their homes.

Individuals that have been exposed or think that they have been exposed to airborne asbestos fibers should have regular medical check ups. Any breathing problems should be promptly reported to the physician. Moreover it is important not to smoke since a combination of asbestos and smoking is particularly dangerous.

Simian Virus 40 (SV40)  - There is some debatable evidence that the SV40 virus (the Simian virus) can increase the risk of developing mesothelioma. However research studies gave an incomplete result and so the correlation (relationship) between this virus and mesothelioma is not clear.

Radiation Thorium dioxide (Therotrast) - This substance was used in x-ray tests in the past and there is some evidence between this substance and both pleural and peritoneal mesothelioma. Due to this discovery thorium dioxide (Therotrast) has not been used for many years.

Zeolite - This is a silica-based mineral with chemical properties similar to asbestos. It is found in the soil in the region of Anatoli (Turkey). Some mesothelioma cases in this region have been linked to this substance.

Tobacco - Cigarette smoking alone does not cause mesothelioma though it increases a person's chances of developing mesothelioma. However, smoking and asbestos exposure not only can cause mesothelioma but also lung cancer.