Causes of Mesothelioma
Mesothelioma, a rare cancer that forms in the protective layer that covers the lungs and abdomen, was virtually unknown until the 19th century when asbestos use became commonplace. Today, up to 3,000 people a year are diagnosed with this deadly disease.
Asbestos, a mineral that forms in the deep layers of the earth, has been used for centuries in clothing and tools because of its heat- and fire-resistant properties. But it wasn’t until the advent of industrial and commercial uses in the early 1900s that asbestos use became widespread. When it became clear that asbestos fibers caused serious health problems, industries were reluctant to acknowledge the dangers. Instead, many companies chose to hide the hazards from their workers.
Types of Asbestos
Asbestos is a general name given to a group of six fibrous minerals that form deep in the earth. These six minerals belong to either the serpentine or amphibole class, depending on the shape and size of the fibers. Unbroken pieces of asbestos look like old wood. But when shattered, the mineral separates to release fluffy fibers into the air.
Of the six asbestos minerals, three are the most common:
- Chrysotile – This form of asbestos has long, curly and flexible fibers and is most commonly used in commercial products, including insulation, roofing shingles and floor tiles. It’s also called white asbestos and accounts for 95 percent of asbestos used in the United States.
- Amosite – Also called brown asbestos, this is known for its brittle and needle-like fibers and is less commonly used. It mostly originates in Africa and was commonly used in pipe insulation and cement.
- Crocidolite – Known for its soft fibers, this form of the mineral is known as blue asbestos. The fibers are easily breakable. It is commonly found in South Africa and Australia.
The Three Most Common Asbestos Types
Asbestos Mining In the United States
Asbestos use can be traced back to as early as 3000 BC, but it was more recently found to be used in early Greek and Roman times in a variety of products, including body armor, funeral shrouds and fire pits.
It emerged in popularity in the U.S. in the early 1900s with the beginning of the Industrial Revolution. At the time, workers wielded pickaxes and shovels to excavate asbestos mines for the precious stones. The pieces were hauled out of the open-pit mines using horse-drawn carriages, and the fibers were hand separated from the rock. Later, large machines took over much of the hard labor. By the late 1960s and early 1970s, some 300 million pounds a year were being removed for a variety of uses.
In the early years, asbestos was thought to be a miracle worker. It could be woven into fabric or mixed into wet and dry materials to make virtually indestructible products. In the 1800s, the first asbestos-containing products in the U.S. were used on steam engines and other high-temperature machinery. By the mid 1800s, the H.W. Johns Manufacturing Company started selling fireproof roofing products that contained asbestos from a New York quarry. When the firm merged with Manville Covering Company in early 1900, it became the largest asbestos manufacturer in the U.S. About the same time, asbestos was being used in the newest technology – the automobile.
In the years that followed, asbestos use grew by leaps and bounds. The U.S. military found so many uses on World War I battleships that it became a standard building material. By World War II , asbestos lined virtually every ship used in the Navy and Merchant Marines. In the U.S. alone, an estimated 1 billion pounds of asbestos was used in shipbuilding each year during the war. By then asbestos was also prevalent in homes and businesses nationwide, used in everything from roofing materials to ceiling tiles to flooring.
How Does Asbestos Cause Mesothelioma?
The problem with asbestos comes when the fibers are released into the air. When they are inhaled, they become trapped in the lungs. Over a period of decades, these fibers cause scarring, inflammation and damage to the cells on the mesothelium, which is the membrane that lines the chest and abdomen. This all leads to mesothelioma.
Although researchers discovered the negative health effects as early as 1899, U.S. lawmakers did not put restrictions on its use until the early 1970s. Today, there is no law banning asbestos in the U.S., but the U.S. Department of Health and Human Services and the U.S. Environmental Protection Agency have declared it a human carcinogen and said there is no safe level of exposure. Even still, it is current being used in hundreds of consumer products.