Common Forms of Asbestos

Every year between 2,000 and 3,000 new cases of Mesothelioma are diagnosed in the United States. Many people understand that exposure to asbestos is the most common factor in developing this rare and deadly cancer. What is less discussed is that there are actually six different types of asbestos, and type can influence exposure.

The six types of asbestos are divided into two categories: Serpentine – identified by the presence of layered, curly fibers, and Amphibole – identified by longer, chain-like fibers. Amphibole fibers tend to be sharp and easy to inhale.

Serpentine

Chrysotile, also known as white asbestos, is the most common form of asbestos used worldwide and can be found many places throughout the U.S. It has been used in roofs, ceilings, walls, and floors in both commercial and private residences. Approximately 90 – 95% of all asbestos still present in buildings in the U.S. and Canada is Chrysotile. Due to its widespread use, including automobiles and the military, Chrysotile accounts for most health problems.

Chrysotile is still mined today, though companies maintain that it is safer than it once was. The Chrysotile once sold on the market was brittle and very toxic. Modernly, it is encapsulated in cement or resin to help protect workers and the public from the toxic fibers. Even with the precautions taken in manufacturing, however, exposure to even small amounts of Chrysotile can cause cancer, as demonstrated by the higher number of Mesothelioma cases around Chrysotile mines.

Amphibole

There are five types of Amphibole asbestos: Actinolite, Amosite, Anthophyllite, Crocidolite, and Tremolite. Of these, Amosite and Crocidolite were widely used up until the 1980s, with Amosite being the second most likely form of asbestos found in buildings. Because of the long, straight fibers, less exposure to Amphibole asbestos is needed to cause mesothelioma compared to Chrysotile.

Amosite, also known as brown asbestos, occurs naturally as the mineral grunerite. While about 80,000 tons of amosite was mined in South Africa by 1970, it is no longer mined today. Most countries banned the use of this type of asbestos about 30 years ago. Because of its common use, including piping and electrical insulation, many individuals were exposed to this form. The American Cancer Society has stated that exposure to amosite carries a higher risk of cancer than any other type of asbestos. In addition to mesothelioma, amosite can cause lung cancer and asbestosis.

Crocidolite once accounted for only about 4% of asbestos used in the U.S. Known as blue asbestos, it is harder and more brittle than other forms. As a result, it breaks easily and can release needle-like fibers that are easy to inhale. Because of this, it is the most lethal form of asbestos and can lead to lung cancer and mesothelioma.

This type of asbestos was used for fire protection, spray on insulation, and making yarn. Crocidolite was mined in Australia, Bolivia, and South Africa as early as the 1880s. Crocidolite mining accounted for the most exposure to the mineral in both miners and those living around the mines. Due to exposure, one of the old mining towns, Wittenoom, Australia, is now a ghost town with only eight residents.

While Amphibole asbestos is not in use in most countries today, some can still be found in a few buildings and products. In addition, Amphibole asbestos may be mined concurrently with Chrysotile, which can lead to exposure for both miners and those living in communities surrounding the mines. Understanding the differences in the types of asbestos can help miners, companies, and communities address health issues that may arise and lead to better outcomes for those exposed.