Asbestos is a mineral fiber that is resistant to heat and corrosion. It has been used widely in building materials like insulation, ceiling tiles, floor tiles, cement sheets, and roofing for its strength and heat resistance. However, asbestos fibers are highly toxic if inhaled and have been linked to diseases like asbestosis, lung cancer, and mesothelioma. The document outlines the different types of asbestos - chrysotile, amosite, crocidolite, anthophyllite, tremolite, and actinolite - and which building products they have been used in, such as insulation, fireproofing, plastics, and cement sheets.