Asbestos mittens were used regularly to protect workers' hands in industrial and manufacturing work. Mittens that were made before the 1980s almost certainly contained a significant amount of asbestos. Workers involved in foundries, glassworks, steel plants, welding, and even fire fighting have possibly been exposed to such a product. Any industry that exposes its workers to extreme hot and cold can have possibly exposed them also to a very dangerous material, while trying to protect them.The use of asbestos in protective clothing was very common from the beginning of the 20th century up until the 1980s. Mittens could contain up to 40 percent asbestos. They were most often made from using chrysotile asbestos, a type of the mineral most commonly used in United States industrial applications. This specific type of asbestos originated in Canada, though deposits of it can be found in the United States and in Europe. Though some have questioned whether this form of the mineral is as dangerous to one’s health as the riebeckite and amosite forms are known to be, exposure to any form of asbestos is dangerous. Workers who wore asbestos mittens were not only exposed during the time they wore the mittens. It wasn't as simple as removing them carefully and washing one’s hands to prevent the result of exposure. Because fibers from asbestos are so small and easily airborne, they were regularly inhaled at work and deposited in the lungs and esophagus. Not only were they immediately inhaled, but they were deposited on the hair and clothing material of the one exposed, allowing for increased chances of exposure well beyond the time of actual use.