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Pleural Mesothelioma Risk Factors

Although practically everyone has been exposed to asbestos fibers to some extent, the greatest mesothelioma risk factors are primarily occupational. Asbestos was ubiquitous in virtually every industrial occupation, particularly shipbuilding, oil refining, power generation and construction/demolition.

The Problem Remains

Most commercial uses of asbestos were outlawed in the United States in the late 1980s and early 1990s; the use of deadly amphibole asbestos (the "blue" and "brown" varieties) has been virtually eliminated for 30 years. However, there are hundreds of thousands of buildings and homes standing in which such asbestos products remain. In addition, the sea-going vessels of some nations, such as Greece, are still full of asbestos insulation, particularly in the engine rooms (vessels registered in the United States and most other industrial nations have either had asbestos removed or sealed up).

Other occupations in which mesothelioma risk factors are high are railroad workers and automotive service technicians. Asbestos was for many decades used in brake linings as well as gaskets and firewalls. Paper and pulp mills (where asbestos drying felt was used) were yet another workplace where employees faced asbestos hazards.

Finally, military veterans – particularly those who were in the maritime services – are especially at risk, due to the extensive use of asbestos in naval vessels.

Secondary Exposure

Industrial workers unknowingly endangered their families, bringing asbestos fibers into the home on their hair and on their clothing. There have been numerous documented cases of mesothelioma resulting from secondary exposure.

Tobacco Use

Mesothelioma has not been correlated with the use of tobacco; however, it is worth noting that individuals who have had high exposure to asbestos on the job and who smoke cigarettes run a risk of contracting lung cancer that is as much as 90 percent greater than non-smokers who have not been around heavy concentrations of asbestos and do not smoke.

Other Mesothelioma Risk Factors

Recently, a significant increase in mesothelioma cases among mine workers in northeast Minnesota was noted. The culprit appears to be taconite, a byproduct of iron mining. This is not asbestos, but the mineral has a crystalline structure that is very similar.

Thorium dioxide also has a molecular structure that is similar to amphibole asbestos. In addition, this substance, which was once used to develop X-ray images, is radioactive; radiation has long been associated with a number of cancers.

Finally, there is the question of Simian Virus 40 (SV40).  It is not known for certain that this virus, which contaminated some polio vaccines during the late 1950s and early 1960s, is actually a risk factor for humans, but has produced the disease in lab animals. Since the symptoms of mesothelioma do not normally appear until a person is past the age of 50, it will be a few years before it can be determined if exposure to the contaminated vaccine can be listed with other mesothelioma risk factors.

Sources

1. http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_malignant_mesothelioma_29.asp?sitearea
2. Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)