What diseases are caused by asbestos exposure?

As asbestos fibres accumulate in the lungs, several diseases may occur:

Two principal kinds of cancer:

Mesothelioma is a cancer of the pleural and peritoneal lining and is considered to be almost exclusively related to exposure to asbestos. It is almost always fatal with those affected usually dying within 1 or 2 years of diagnosis. Mesothelioma has a long latency period (i.e. the time between initial exposure and the onset of the disease) that is typically between 30 and 40 years.
Lung Cancer is a malignant tumour of the bronchi - the tubes carrying air to and from the lungs. The tumour grows through surrounding tissue, invading and often obstructing air passages. Again, the disease has a long latency period - typically at least 20 years.
Non-malignant lung diseases:

Asbestosis is a scarring of the lung tissue. This scarring impairs the elasticity of the lung, restricting their expansion and hampering their ability to exchange gases. This leads to inadequate oxygen intake to the blood. It is a slowly progressive disease with a latency period of 15 to 30 years.
Diffuse pleural thickening is a non-malignant disease in which the lining of the lung (pleura) becomes scarred. If it is extensive then it, too, can restrict expansion of the lungs and lead to breathlessness. It normally takes at least 10 years after the first exposure to develop asbestos related pleural disease. The disease is a chronic condition with no cure.
Small areas of scarring are called pleural plaques. They do not cause symptoms.