Asbestos is a long, thin, fibrous mineral made of up of microscopic crystals. There are six different types that are split up into two different groups: serpentine or amphibole. Serpentine asbestos is classified by its layered structure and curly fibers. One particular type of serpentine asbestos – chrysotile – is most commonly found in building materials throughout the United States. Amphibole asbestos is characterized by its long, chain-like structure. The fibers are sharp and straight, making them very easy to inhale.

Asbestos has been used for at least 4,000 years – archeologists have found it in ancient clay pots, presumably to protect the dishes when being used in cooking fires. However, it was not mined at a large scale until the industrial revolution in the 19th century. At that point, manufacturers and builders started to use the product, taking advantage of beneficial properties, including its strength, sound absorbance, and particularly its resistance to fire, heat, and electricity. Also, it’s a fairly abundant mineral, making it pretty cheap to mine and affordable to produce.