Latency refers to the length of time between the first exposure to a toxic or carcinogenic substance such as asbestos, and the onset of the disease caused by the toxin. Most asbestos-related diseases have a long latency period of at least 10 to 40 years.

For example, it typically takes 20 to 40 years to develop malignant mesothelioma after being exposed to asbestos. Likewise, it usually takes 20 to 30 years after the first exposure to develop pleural plaques, asbestosis, or asbestos-related lung cancer. In some cases, the latency period may be as short as 10 years after exposure. In other cases, it may take 50 years or more.

This can make it hard to identify all of the sources of your past asbestos exposure after you are diagnosed with an asbestos-related disease. Your disease may have been caused by a product that you worked with during the 1960s , 1970s, or 1980s, and even as far back as the 1940s or 1950s. It can be difficult to remember all of the sources of exposure after so many years have passed. This is particularly true in cases of mesothelioma which may have been caused by very brief or low levels of exposure to asbestos, including household exposure or bystander exposure.