Asbestos is a naturally occurring fibrous mineral that was commonly used in construction materials in the late 19th and early 20th century. The material was commonly used in insulation, roofing, flooring, and other building materials because it is resistant to heat, fire, and electricity. However, over time, it was discovered that asbestos fibers can become airborne, leading to respiratory problems and even cancer. In 1999, the use of asbestos was banned in construction materials.