The main risk factor for mesothelioma is asbestos exposure.

The main risk factor for mesothelioma is asbestos exposure. The use of the material has been banned in the United States since approximately 1975. The asbestos fibres have also been known to be picked up through clothing or other articles. Not all workers exposed to asbestos will develop diseases related to their exposure. In fact, many will experience no ill effects.

At least 250 members of Australia's emergency services personnel in New South Wales have been informed that they could die from exposure to asbestos. It can take decades for asbestos related illnesses to appear and can take up to 30 years before those exposed can be cleared of infection. Inhaling or otherwise ingesting these fibres can cause an individual to be directly exposed to asbestos, which can lead to a number of serious and potentially deadly diseases. Exposure to asbestos has also been linked to an increased risk of lung cancer and asbestosis. Most individuals who develop an asbestos-related disease have been exposed to asbestos fibres over a prolonged period of time.