Canadian Environmental Health Atlas

Understanding Our Environment is Key to Promoting Health and Preventing Disease

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Asbestos and Disease

Asbestos and Disease

Asbestos and Disease
Exposure to asbestos is associated with a number of diseases, including asbestosis and lung cancer.1

Asbestosis results from inhaling heavy concentrations of asbestos dust, which causes excess connective tissue to form in the lungs. Over time, this scars and stiffens the lung tissue and makes breathing difficult (Figure 1).

Lung cancer is a common type of cancer associated with smoking, ionizing radiation (e.g. radon), and occupational exposures to certain substances, including asbestos (Figure 2). Smokers exposed to asbestos are at particularly high risk for developing lung cancer.

Malignant mesothelioma is a rare and difficult-to-treat form of lung cancer that develops in the mesothelium, the protective lining of the chest cavity (Figure 3). It is nearly always related to the inhalation of mineral fibres. In the majority of cases, mesothelioma is caused by occupational asbestos exposure. Taking many years to develop and causing  no or few symptoms initially, mesothelioma is incurable.

The Toxicity of Asbestos Fibres
Asbestos is especially toxic because of the way it breaks apart to produce thousands of fine fibres These fibres, particularly those less than 2.5 microns in size, are easily inhaled and present a severe hazard to respiratory health (Figure 4).

Fibres that enter the lungs may remain lodged in the tissue for many years. Their toxicity is determined by their size, durability, and iron content. The presence of asbestos fibres in the lungs can lead to inflammation as well as cell and tissue damage, which in turn can lead to diseases related to malignant cell growth and lung scarring and stiffening.