Asbestos is a naturally occurring, fibrous mineral that is formed from the remains of sea sponges and corals. It was used in many building materials and products for over 100 years because it is fire-resistant, heat-resistant, and durable. Asbestos fibers are microscopic, which means that they can enter the lungs through breathing. They can also be inhaled through the skin or ingested. Once inside the body, asbestos fibers can cause cancer by causing mutations in cells. The most common form of asbestos exposure comes from inhaling asbestos fibers that have been released into the air by damaged buildings or during demolition projects.