Asbestos, known as “stone-cotton” in Japanese, consists of natural mineral fibers, each of which is too thin to be apparent.
When this fine asbestos fiber (asbestos dust) is released into the air, it continues to fly around in the air for a long time without disappearing. We human beings inhale this airborne asbestos when breathing. Although a large bundle of asbestos fibers is removed in the nasal cavity, fine asbestos fibers reach the alveolus and get deposited.
As asbestos fibers are durable and rarely transformed, deposited asbestos fibers cut deep into lung tissues. They are highly likely to cause diseases such as lung cancer and mesothelioma after an incubation period of about 20-40 years. The reason that asbestos is dreaded as a “quiet time bomb” is because it causes such an irreversible catastrophe. In the case of malignant pleural mesothelioma, the chance of survival after 2 years of onset is about 20%, which decreases into the extremely low percentage (about 3.7%) after 5 years of onset.