Asbestos is a naturally occurring mineral that was widely used for its excellent insulation properties and fire resistance. However, asbestos is also a carcinogenic substance that can cause serious health problems when its fibers are inhaled. When asbestos-containing materials are disturbed or damaged, such as during renovation or demolition, the tiny asbestos fibers can become airborne and penetrate deep into the lungs, where they can cause inflammation, scarring, and tumors. The health risks of asbestos exposure depend on various factors, such as the duration, intensity, and frequency of exposure, as well as the age, gender, and health status of the person exposed.

There are six types of asbestos minerals, but only three types were commonly used in building materials:

• Chrysotile, also known as white asbestos, is the most common type of asbestos and was used in about 90% of asbestos-containing products. Chrysotile fibers are curly and flexible and can be spun into threads or woven into fabrics.
• Amosite, also known as brown asbestos, was used primarily for insulation and was commonly found in pipe insulation and cement sheets. Amosite fibers are straight and needle-like and can be more brittle than chrysotile fibers.
• Crocidolite, also known as blue asbestos, was the most deadly type of asbestos and was used primarily for marine insulation and spray-on coatings. Crocidolite fibers are straight and thin and can easily penetrate the lung tissues.

Other types of asbestos, such as tremolite, actinolite, and anthophyllite, were also used in some building materials, but they are less common than chrysotile, amosite, and crocidolite.