Asbestos: History, Types, and Health Risks of Mesothelioma

Prior to the last couple decades in the 20th century, asbestos was a sacred part of industrial and commercial America. It’s cheap to purchase, remains durable for years, and can resist fire and heat damage.

Some often-discussed mesothelioma risk factors are still being researched. They include:

Asbestos can be found in many construction materials, such as spray-on insulation and roofing tiles. It’s also found around electrical wiring, switch boards and panels, automobile brakes, paint, floorboards, siding and more. This is why occupational exposure to asbestos is linked to the rise of mesothelioma cases.

Asbestos falls into two mineral families: serpentine and amphibole. There is one type of serpentine asbestos and five types of amphibole asbestos.

Serpentine fibers are long, curly and layered. The only known type is chrysotile. According to the Penn Medicine website, “Chrysotile asbestos is the cause of most cases of mesothelioma.”

Amphibole fibers are short, straight and sharp, similar to a needle or pin. They’re structured in a chain-like formation. According to Penn Medicine, amphibole asbestos is easy to inhale.

According to an article by Mineral Direct, most hazardous fibers are shorter in length because they can travel easily through your body. This is why amphibole asbestos can be harmful. However, both types of asbestos can be dangerous.

There are six different subtypes of asbestos used in products: tremolite, actinolite, anthophyllite, chrysotile, amosite and crocidolite. The two used most often are chrysotile and amosite. These asbestos subtypes can be found in construction materials and automobile parts.

You can find asbestos in homes, schools, offices, automobiles and other vehicles and buildings. Despite the significant reduction in use, asbestos remains dangerous due to its presence in deteriorating buildings.

Even though use of asbestos in new construction has reduced dramatically, the United States imported around 100 metric tons in 2019. The amount rose — nearly doubled — in 2020. The following are home, automobile or office building components that may have asbestos:

Two reports revealed that asbestos can exist in downtown locations of major cities. In 2019, asbestos was found in a New York bus depot. According to the New York Daily News, there was a heavy amount of asbestos that put thousands of MTA employees in danger of exposure.

The depot is a storage location for the buses. Some vents at the depot pump air into each floor of the building. According to the report, most of the vents sending air into the first three floors “are lined with asbestos-laced cloth.” The fan room circulates air through the vents and into the rooms. The number of workers possibly exposed were:

The MTA also has internships for high school students.

Another instance was a pipe leak in downtown Boston that released asbestos dust into the air and on a road. In 2019, a steam pipe leak caused Boston city officials to close down several streets around Summer Street and Downtown Crossing.

Asbestos leaked through a manhole and caused dust to litter the street. A picture posted to the Boston Fire Department’s Twitter account shows a white substance covering the road and a parked car. It’s unknown how many residents were in the area at the time of the leak.

Mining for asbestos in the United States started in the late 1800s. It continued the entirety of the 20th century. Mining occurred to meet high industrial demands for the mineral.

Today the U.S. solely imports asbestos for just a few industrial uses, notably to produce chlorine and sodium hydroxide (chlor-alkali).

Asbestos mining involved an open-pit (an open area similar to a valley) method. When asbestos is first extracted, it looks like old wood. It is then turned into a fluffy fiber. The refined asbestos is added to other materials, like cement or insulation.

Mining of asbestos in the United States ended in 2002 when a chrysotile deposit in California closed. The U.S. still imports it, and in 2018 the country brought in 750 metric tons:

From 2006-2014, the U.S. imported more than 8 million pounds of asbestos. Most of the asbestos came from Brazil.

From 2006-2014, the port bringing in the largest amount of asbestos was New Orleans, Louisiana. The following ports in the United States are known for receiving large shipments of asbestos:

The most famous asbestos mine was the vermiculite mine in Libby, Montana. The mine included amphibole asbestos. It shut down in 1990 and is responsible for many mesothelioma cases.

The Agency for Toxic Substances and Disease Registry lists 27 processing sites for Libby’s vermiculite mine. One of them is Libby, and the other 26 locations are:

Asbestos was once mined in nearly half of the states in the country. The U.S. Department of Interior reported 27 former asbestos mines in North Carolina and 17 in Georgia. Other states are: