A distinguishing feature of mesothelioma is the particularly protracted periods of time involved before symptoms become clinically apparent. This called the latency period.

Of the asbestos-related diseases, mesothelioma has the longest latency. On average, it is not unusual for 35 to 40 years to elapse between exposure to asbestos and diagnosis of mesothelioma or asbestosis. There have been cases of diagnosis 50 or more years after exposure, or in as little as 10 years. Malignant pleural mesothelioma (lung) is most often diagnosed between ages 40 and 69. A large proportion of mesothelioma patients diagnosed earlier than age 40 have a history of asbestos exposure during childhood.

Making a claim for mesothelioma compensation after this time is not unusual as most mesothelioma patients are in their 40s to 60s. The disease can occur even in childhood, though it is extremely rare – only two to five percent of cases of malignant mesothelioma develop in the first two decades of life. Asbestos exposure in these cases may be environmental or may not be able to be identified at all.

Higher exposure to asbestos may result in a shorter latency period. Patients having a greater amount of asbestos fibres in the lungs may have shorter latency times. The highest asbestos burden and the shortest latency times have been shown in patients who were occupationally exposed during jobs within shipyards, heavy manufacturing industries and the asbestos and insulation industries.

Although asbestos awareness has considerably improved, the very long latency period of mesothelioma contributes to its poor prognosis and remains undetected for a very long time compared to most cancers. When it finally reveals itself in physical symptoms, it has likely gained a strong foothold during this latency period. By the time a diagnosis is reached, the mesothelioma may be further advanced.

Peak incidence of asbestos-related diseases is expected to occur about 30 to 40 years after the years of greatest asbestos usage.

The challenge for undertaking the mesothelioma claim process is because the latency period for mesothelioma is so long that it can sometimes be difficult to pinpoint the timeframe for asbestos exposure, and because many workers in years past simply didn’t live long enough after retirement for the 30- or 40-year latency period to catch up with them.

Workers retiring at an age of 65 now have a longer life expectancy. Additionally, asbestos regulation has successfully reduced the amount of exposure, so that workers who are exposed to asbestos are generally encountering a much lower level than they were in previous years.

Mesothelioma can sometimes develop after only short-term exposure, and thirty or forty years later the patient may not be able to pinpoint where exposure may have occurred if it was a relatively short exposure of several weeks during late teens or early twenties.