Causes of mesothelioma

Virtually all mesotheliomas are caused by asbestos.

Blue and brown asbestos are much more potent in causing mesothelioma than white asbestos, but all asbestos is capable of causing mesothelioma. The asbestos that causes the mesothelioma is likely to have been breathed in 10 or more years before symptoms develop.

Usually, if a careful enough history is taken from the patient, he or she will remember some exposure to asbestos. In a very small number of cases, mesothelioma develops after no known asbestos exposure.

It is common for people not to remember at first that they have breathed in asbestos when asked about this at hospital. Or they may not know that materials they worked with contained asbestos. A detailed occupational history has to be taken by someone who will ask the right questions.

There is no “safe” minimum dose of asbestos, including white asbestos (chrysotile), below which you can say there is no risk of mesothelioma. But the risk of mesothelioma increases the more asbestos you have inhaled in your life.

Challenges by the insurance industry and employers to compensation for mesothelioma in the court system have concentrated on causation.

In 2002 insurers argued that because mesothelioma could in theory be caused by just one asbestos fibre, someone who had worked for more than one employer could never prove where that fibre came from. Having lost that argument, insurers are currently arguing that minimal asbestos exposure does not cause mesothelioma.

Acre Mill, Hebden Bridge, West Yorkshire. Operated by Cape plc. Originally built to make gas mask filters during World War II. Many former workers developed mesothelioma.

Thanks to Frank Woolrich, Hebden Bridge Historical Society.