The Facts about Different Asbestos Types
Not all asbestos is created equal. You’ve probably already ascertained that not everyone who is exposed to asbestos gets mesothelioma cancer or some other related disease. Similarly, some types of asbestos are more likely to cause these cancers than other types.
That said, however, over the years it has been established that exposure to ANY kind of asbestos can be toxic and even a small degree of exposure can be cause for alarm.
What is asbestos?
Asbestos is a naturally-occurring mineral. That is, it is found in the ground and can be mined. Throughout much of the 20th century, it was used as an insulator because of its unique heat-resistant properties, and was also found in thousands of other products that were used in many different industries.
Canada was once one of the major miners of asbestos but has halted asbestos mining in the last several years after a 130-year relationship with the mineral. Russia, China, and Africa continue to cultivate asbestos.
Six different types of asbestos have been identified and these types are divided into two groups:
Serpentine – As the name indicates, this sub-type of asbestos has curly fibers and also boasts a layered structure. Only one variety of asbestos appears in this category – chrysotile – the type that was most often used in commercial products and, hence, the variety that is found in the vast majority of asbestos-containing products that were used in the United States.
Amphibole – Rather than curly fibers, this type of asbestos is identified by its long chain-like structure. Fibers that come from amphibole asbestos are easy to inhale because they are straight and quite sharp. The remaining five types of identified asbestos are part of this category and include amosite, crocidolite, anthophyllite, tremolite, and actinolite. After chrysotile, amosite and crocidolite were the most-used varieties and, hence, some U.S. cases of mesothelioma have been linked to exposure to these two types.
Aside from being categorized by their structure, asbestos types are also referred to in regards to their color. However, tremolite, anthophyllite, and actinolite – the rarest types of the mineral – remain unclassified.
Chrysotile – white
Amosite – brown
Crocidolite – blue
Asbestos Mining History
Naturally-occurring asbestos can be found on all continents, including the Antarctic. The history of its use dates back to several thousand years BC, when it is said that ancient civilizations used asbestos to make wicks for candles, to make cloths in which to wrap the dead (to avoid deterioration of the body), and to make pottery that would withstand wear-and-tear and could be used to cook over fire without being destroyed.
In the 8th century AD, it was reported that King Charlemagne ordered his tablecloths be made from asbestos so that they’d survive the raucous parties he threw, which often involved accidental fires from candles tipping over.
There are also reports that asbestos bags were used as weapons during the Crusades, filled with flaming pitch and tar.
Other uses are too numerous to mention, but it’s clear from historical records that asbestos was indeed a novelty and enjoyed many eclectic uses thanks to its reputation for strength and fire resistance. These uses and others would continue through the centuries and later burgeon after the Industrial Revolution.
Though asbestos has been mined for centuries (Pliny the Elder wrote about asbestos mining dangers during the days of the Holy Roman Empire), modern asbestos mines began to spring up in earnest in the late 19th century.
The Canadians were the first in the world to establish commercial asbestos mines for the mining of chrysotile asbestos. The Russians also began to mine chrysotile around that time and continue to do so. The Germans and Brits also dabbled in chrysotile mining for a while.
More dangerous tremolite asbestos was mined in Italy, and the Australians mined toxic blue asbestos in Wittenoom, a town in the far reaches of Western Australia, in the early 20th century. The town once boasted some 13,000 residents, about half of which worked in the mines. More than 2,000 have died of mesothelioma and Australia has literally removed Wittenoom from the map.
Six residents refuse to leave. The mines of Wittenoom closed in the 1960s and there is clear evidence that officials knew the mineral was killing its workers and their families, but continued with the endeavor nonetheless.
Today, Brazil, China, Russia, Kazakhstan, India, Zimbabwe, and Swaziland still run asbestos mining operations. The first five remain the top importers of the mineral, with Russia importing more than 600,000 metric tons in 2014.
China is the largest consumer of asbestos though much of the mineral is imported to Third World countries where unsuspecting citizens use it to fashion products like roofs and siding for their homes, unaware that they’re being exposed to something toxic.
Different Types Of Asbestos Particulars
It’s helpful to know the details about each form of asbestos and how and where it was used. This helps doctors know what they’re facing as far as severity of disease, and identifying the type can assist those filing legal action as well.
Chrysotile is the most common form of asbestos and, hence, was the type most often used in commonly-manufactured products that dominated the U.S. market throughout the 20th century. As such, it is to this type of asbestos that most Americans were exposed.
The Canadians and others who are/were deeply involved in chrysotile mining have longed tried to convince the general public that this type of asbestos is not hazardous though, certainly, studies have shown that not to be the case.
Additionally, naturally-occurring deposits of white asbestos can often be tainted by trace amounts of tremolite asbestos, which increases its toxicity. Researchers note that chrysotile should be treated with the same respect as the other types of asbestos.
Chrysotile was used in a multitude of fireproofing and insulation products. It was a regular component in products that were used aboard U.S. military ships from the 1940s until the end of the 1970s. Hence, most veterans who have mesothelioma were exposed to the chrysotile form of asbestos.
It was incorporated into an abundance of construction products including cement, floor and ceiling tiles, glues and mastics, drywall and fiberboard, shingles, siding, and more. Chrysotile was also used in friction products for the auto industry, such as brakes, pads, and clutches.
Because of its fireproofing properties, it was even used in protective clothing worn by those whose jobs were high risk for burn injuries. This included, ironically, face masks.
Throughout the 20th century, amosite or “brown” asbestos was the second-most commonly used form of the mineral. Much of it was mined in Africa though the mining of this dangerous mineral was halted during the first decade of the 21st century.
By that time, more than two dozen countries had already banned the use of amosite, though you’ll still find this type of asbestos in old buildings in the U.S. and in other countries as well. It crumbles easily when old and damaged and can be readily inhaled.
Amosite was also largely used for insulation purposes and could be found in fire protection products, thermal insulation, pipe linings, electrical insulation, tiles, roofing products, lagging, gaskets, and more. It was long lauded for its amazing strength, so adding it to certain products gave them the ability to last much longer. Like chrysotile, it was also a good fire- and heat-resistant material.
The brittle “blue” asbestos known as crocidolite is hard and can break easily, sending its sharp tiny fibers into the air where it is likely to be inhaled by anyone in the vicinity. It is considered the most toxic form of asbestos and was used as reinforcement materials for plastics and as an ingredient in ropes and lagging to make them stronger and longer lasting. It was rarely used in the U.S. so exposure to crocidolite is fairly rare.
Most of the crocidolite used throughout the world was mined in Western Australia, Bolivia, and South Africa. Its toxicity is demonstrated by the number of crocidolite miners that have died due to asbestos-related cancer.
Specifically, studies show that nearly 20 percent of crocidolite miners have succumbed to the effects of crocidolite exposure. In the aforementioned town of Wittenoom, Australia, thousands have passed away, including not only miners but also citizens of the town and extended family of the miners who suffered second-hand exposure.
Crocidolite was used in the manufacture of thermal insulation, spray-on insulation, ceiling tiles, millboard, cement sheets, telecommunication wires, chemical insulation, and fire protection products of various sorts.
Thankfully, only 4 percent of the asbestos identified in products used in the U.S. contain dangerous crocidolite asbestos.
Tremolite is usually found in other minerals including talc and vermiculite. When these minerals are mined, they can be contaminated with tremolite. A good example of this was the vermiculite mine owned by W. R. Grace and Company in Libby, Montana.
The company used the tainted vermiculite to make insulation and countless Grace employees, along with users of their Zonolite ™ insulation, were sickened by asbestos. There has also been reports of high incidences of cancer among talc miners in Minnesota and other parts of the northern portion of the United States.
The mineral is not classified by its color because it can be of a variety of colors including white, green, brown, or gray. It has also been used, historically, in paints and sealants.
Anthophyllite is a very rare form of asbestos and, hence, exposure to it is fairly uncommon. Nonetheless, the few studies that have been done involving this variety of asbestos do indeed show that inhaling anthophyllite fibers can be dangerous, though perhaps less so than inhaling fibers or dust from chrysotile or the other more common varieties.
Trace amounts of anthophyllite may be found in the mineral talc and, as such, could be present in products made with talc, such as talcum powder.
A member of the amphibole family of asbestos, actinolite is rather the chameleon of asbestos types, appearing in a variety of different colors from white to dark brown. It is usually fibrous and very brittle, making it very dangerous and easy to inhale.
Actinolite is generally used in combination with vermiculite to manufacture insulation, structural fireproofing, concrete materials, sealants, drywall, paints, gardening products, and joint compounds.
Actinolite has also been detected in some children’s toys including crayons and so-called crime scene kits that children use to play detective. All of the children’s items identified as containing actinolite asbestos were manufactured in China.