Asbestos is a naturally-occurring mineral that is found in deposits located around the world. It has been mined heavily in the United States, Canada, and Africa, and all types of asbestos have a high resistance to heat and operate as excellent insulators. Unfortunately, asbestos can also be deadly to humans and can cause an aggressive form of cancer known as Mesothelioma.
While it is possible to contact this cancer from any of the types of the asbestos, some are more prone to cause the disease in humans, and some were used more broadly for manufacturing purposes than others. There are six main types of asbestos under two broad categories - serpentine and amphibole - and each of them poses a hazard to humans if their fibers are inhaled in a sufficient quantity.
The only type of serpentine asbestos defined as such by the US Environment Protection Agency is chrysotile asbestos. It is a member of serpentine group because the fibers that make up its structure are curly, and it is considered to be the most flexible type of asbestos. Its fibers are able to withstand significant heat and are also soft enough that they can be spun into cotton. With a high resistance to alkalines, chrysotile was used in a wide variety of building products, and was the most commonly mined type of asbestos, accounting for over 95% of asbestos used. This type of asbestos is less likely to become friable (easily breakable), and it is less likely that humans will inhale chrysotile fibers than those of other types of asbestos.
The other main group of asbestos types defined by the EPA are of the amphibole type, and include tremolite, actinolite, anthophyllite, amosite, and crocidolite asbestos. All of these kinds of asbestos have straight rather than curly fibers, and are much more easily made friable, increasing the chances that a fiber could be inhaled and become stuck in the lungs. Tremolite was not often used commercially, though it can be found occasionally in products such as talcum powder; actinolite was also rarely used, but is one of the most dangerous of the amphibole types of asbestos, as its fibers can easily become airborne and then inhaled. Anthophyllite can be found in some vermiculites, but was not often used in commercial or industrial applications. Amosite asbestos, also known as brown asbestos or Grunerite, is a type of asbestos that was heavily mined in Africa. This amphibole asbestos was used in cement sheeting and pipe insulation, as well as fire protection on steel and was used to make insulation boards in the US, Canada and the UK. While it is not the most commonly mined, found typically in Africa and Australia, crocidolite asbestos is widely regarded as the most deadly form of this mineral.
The fibers of this type of asbestos are long and needle-like, and in addition to having a high acid resistance are also the strongest of any of the six types of asbestos. Crocidolite was used in rope lagging as well as preformed insulation up until the 1950s, when it became apparent that this type of asbestos was causing serious health issues in humans. It was crocidolite that formed the basis of the first type of sprayed insulation, thanks to the high bulk volume of crocidolite fibers. Unfortunately, this spraying also rendered the asbestos friable, and allowed it to be easily inhaled by anyone working with it. By the 1960s, shipments of crocidolite had fallen by 25 percent to places like the UK, and by 1970, they had dropped by over 85 percent. Countries around the world now either outright ban the use of crocidolite, or have strict regulations regarding its handling and disposal.
While two of the six types of asbestos were more commonly used in both industrial applications and production, and while chrysolite is considered the "safest" type of this mineral, all forms of asbestos can cause mesothelioma if they are inhaled. No matter the type of fibers - straight or curly - they can become lodged in the lungs, where they can lie dormant for years or even decades. If you or someone you know has been affected by any type of asbestos inhalation, fill out the form on this page for more information about treatments, research, and help that is available. Mesothelioma is both aggressive and pernicious, but strides are being made in many areas to not only detect this cancer before it becomes too widespread, but also effectively remove it and help patients recover from their exposure.