Mesothelioma Causes

Asbestos exposure is the only proven cause of malignant mesothelioma. Inhaled or ingested asbestos fibers can mutate cells in the linings of the lungs, abdomen, heart, or testes, causing mesothelioma tumors. Veterans make up a third of all diagnosed cases. Learn more about mesothelioma causes below.

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What Causes Mesothelioma?

Inhaling or ingesting asbestos fibers is the only known cause of mesothelioma cancer.

Asbestos is an extremely durable, naturally occurring mineral. Asbestos fibers are light and can float in the air for long periods, so they’re easy to inhale or ingest unintentionally.

Exposure to asbestos can happen in three primary ways, including:

  1. Occupationally: This is the most common type of asbestos exposure. Many mesothelioma patients had past on-the-job asbestos exposure.
  2. Secondhand: People exposed to asbestos in their occupation may have unintentionally exposed their family members as well. Asbestos fibers can get stuck to clothing. These fibers may be released at home where other people can breathe the fibers. This is called secondhand exposure.
  3. Naturally: Asbestos is a naturally occurring mineral. There are deposits of the fibers in some parts of the United States. People living near asbestos deposits or mines may breathe in the fibers nearby.

Asbestos fibers are like tiny needles that bore deep into body tissues where they are not easily dislodged or coughed out. Over time, asbestos fibers cause inflammation and scarring of body tissues. Prolonged irritation may eventually change the DNA of nearby cells, resulting in cancer.

Once asbestos fibers enter the body, they can remain there for decades before mesothelioma develops.

Did you know

It can take mesothelioma can take 10-50 years, which is why symptoms take so long to show up after asbestos exposure.

Inhaled fibers eventually migrate to the lining of the lungs or the lining of the heart while ingested fibers can migrate to the peritoneum, the lining of the abdominal cavity. As a result, mesothelioma can develop in the lining of the lungs, abdomen, or heart.

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How Does Mesothelioma Develop?

Cancers like mesothelioma develop when something alters the DNA inside cells. DNA mutations cause cells to grow and divide uncontrollably.

Normal cell DNA tells the cells how to grow, divide, and die. When asbestos fibers damage the DNA of otherwise healthy mesothelial cells, the affected cells stop behaving as they should. Instead, they continue to divide and grow when they are not supposed to.

Mutated cancer cells grow uncontrollably to invade healthy tissue, form mesothelioma tumors, and spread throughout the body. You can be diagnosed with different types of mesothelioma depending on where the tumors first develop.

  • Pleural Mesothelioma Causes

    When asbestos fibers are inhaled, they travel through the chest wall to the lining of the lungs, called the pleura, and settle there permanently. The needle-like fibers irritate the tissues for many years until cell DNA becomes damaged, and malignant pleural mesothelioma tumors begin to form.

  • Peritoneal Mesothelioma Causes

    If the asbestos fibers are swallowed instead of inhaled, they can become lodged in the membranes that line the abdominal cavity and organs, called the peritoneum. Prolonged inflammation of the abdominal lining can eventually lead to peritoneal mesothelioma.

  • Pericardial Mesothelioma Causes

    It’s unclear at this point exactly how asbestos travels to the heart lining (pericardium) to cause pericardial mesothelioma. Pericardial mesothelioma is the rarest form of the disease, and experts have a limited understanding of its pathology (how it develops).

Establishing the Link Between Asbestos and Mesothelioma

Asbestos fibers are extremely strong, heat-resistant, and resilient against chemical wear. Because of these durable properties, the use of asbestos was common in many products like insulation, floor tiles, roofing, and brake linings. This was before the general public knew that asbestos was dangerous.

Close-up of asbestos fibers

Medical evidence linked asbestos to mesothelioma in the mid-20th century, but the connection wasn’t formally established until much later. The mineral remained uncontrolled by law until the late 1970s when it became clear that asbestos causes mesothelioma.

The Environmental Protection Agency (EPA) banned certain asbestos products in 1973. Since that time, sufficient scientific and medical evidence has shown that asbestos causes mesothelioma. However, asbestos was frequently used in military applications before the material's use was heavily restricted.

Because of its durability, asbestos could be found in many products used to build:

  • Aircraft
  • Cars
  • Military bases
  • Navy ships
  • Tanks
  • Other buildings

Veterans who served in the U.S. military from the 1930s to the early 1980s may have experienced long-term asbestos exposure in various capacities.

All types of asbestos are considered human carcinogens by the World Health Organization, the International Agency for Research on Cancer, the U.S. Department of Health and Human Services, and the U.S. Environmental Protection Agency.

On March 18, 2024, the EPA banned the importation and use of chrysotile asbestos, which is the type most commonly used.

Where Is Asbestos Found?

Asbestos was used throughout the 20th century in thousands of industrial and home applications. Since asbestos was widely used in the military, veterans had a high risk of exposure.

American Flag Icon
Each year, 900-1,100 Veterans are diagnosed with Mesothelioma
Pleural Mesothelioma
Peritoneal Mesothelioma
Pericardial Mesothelioma
*Sources: American Cancer Society,
National Institutes of Health

Branches of the military that were most significantly affected by asbestos include the Navy, Coast Guard, Air Force, Army, and Marines. Certain non-military occupations also presented a high risk of asbestos exposure.

Examples of workers who had an increased risk of asbestos exposure include:

  • Auto mechanics: People who were involved in manufacturing cars or repairing brakes may have been exposed to asbestos used in automobile parts.
  • Boilermakers: Boilermakers may have come into contact with asbestos used to insulate water heaters.
  • Brick and stone masons: People who worked with brick and stone may have inhaled asbestos fibers found in bricks and asbestos dust used in mortar.
  • Carpenters and construction workers: These workers were frequently in contact with asbestos used in insulation, flooring, and roofing materials.
  • Factory workers: People working in factories producing asbestos-containing products may have been directly or indirectly exposed to airborne fibers. Asbestos was also used in factory machines and transportation belts.
  • Shipyard workers: Shipyard workers are particularly prone to developing mesothelioma and other asbestos-related diseases due to the use of asbestos-containing insulation in the construction of ships and submarines.

Even today, some occupations still put people at higher-than-average risk of asbestos exposure. Firefighters, electricians, HVAC workers, construction workers, and automobile mechanics may be exposed to asbestos on the job.

Get our Free Veterans Packet to learn if a job you worked may have put you at risk.

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Other Asbestos-Related Diseases

Asbestos can destroy healthy cells in unexpected ways, causing other illnesses besides mesothelioma.

Some other health problems associated with asbestos exposure include:

  • Asbestosis: Asbestosis is a benign (non-cancerous), chronic lung disease caused by prolonged exposure to asbestos. When inhaled, asbestos fibers can become lodged in the alveoli — tiny sacs in the lungs that process oxygen. This makes it harder to breathe. Over time, asbestosis can result in lung tissue scarring, which can restrict breathing even more.
  • Lung cancer: Another type of cancer caused by asbestos is lung cancer. Asbestos fibers can pierce the lungs themselves and damage cell DNA over time, leading to the development of cancerous cells in lung tissue. This is not the same as mesothelioma.
  • Pleural disease: Pleural disease is also a benign condition. Asbestos fibers cause changes to the lining of the lungs, or pleura, which may become inflamed and thickened. Pleural disease can also cause fluid buildup in the pleural space. Both of these issues make it harder for the lungs to expand while inhaling.

Most cases of mesothelioma are caused by occupational asbestos exposure, making certain workers more at risk for asbestos-related diseases than the average person.

Still, anyone with a possible history of asbestos exposure should monitor themselves for symptoms of mesothelioma, as there are many cases of secondary exposure.

Worried About Asbestos Exposure?

Many people who worked in the construction and manufacturing trades have been exposed to asbestos, and some of them worry that they might develop an asbestos-related disease. Shipyard workers, mechanics, and miners also have a very high risk of past exposure.

Additionally, veterans may be particularly concerned about their future health since they have a higher risk of developing mesothelioma.

Did you know

Your risk of mesothelioma increases with the amount of time you were exposed to asbestos. Further, there is no safe amount of asbestos exposure. Even small amounts of asbestos can cause mesothelioma after many years of regular exposure.

It’s also important to consider the time period in which you worked in risky occupations. Veterans who served in the military before the 1980s were likely exposed to more asbestos than those who served later on. However, even after asbestos use was controlled, some buildings, vehicles, and machinery still contained asbestos.

If you’re concerned about your history of asbestos exposure, you should visit your doctor or an oncologist. Your doctor will review your symptoms and exposure history and decide if you need further tests.

Why Were People Exposed to Asbestos?

Unfortunately, the majority of companies using asbestos in the mid to late 20th century knew that asbestos was dangerous.

Did you know

There is evidence that countless corporations continued using asbestos in their products after conducting research on the mineral and finding that it was cancer-causing.

Asbestos companies decided that the affordability and abundance of asbestos outweighed the costs of potential lawsuits. These companies continued to supply the military with asbestos-containing materials that eventually exposed countless service members.

Eventually, public research confirmed the dangers of asbestos. Measures were taken to reduce occupational exposure to asbestos during the second half of the 20th century. However, the mineral was still used in products for years.

As the link between asbestos and health problems became public knowledge, people began filing lawsuits against their former employers.

Get Help for a Mesothelioma Diagnosis

When you know more about mesothelioma risk factors, you can better understand the disease, how it affects your body, and what can be done to treat it.

Your asbestos exposure history is an important factor in determining your diagnosis and developing the best course of treatment for your illness.

Here are some things to remember about the causes of mesothelioma:

  • Asbestos is the only proven cause of mesothelioma.
  • Most people were exposed to asbestos in their jobs.
  • Veterans are more likely to develop mesothelioma because asbestos was widely used in most military branches.

Mesothelioma is a devastating disease that can be extremely expensive to treat. Fortunately, there is help for veterans who developed mesothelioma after being exposed to asbestos in the military.

Contact our team today for help finding top mesothelioma treatment options.

FAQs About Mesothelioma Causes

How much asbestos exposure causes mesothelioma?

There is no safe level of asbestos exposure. Any amount of asbestos exposure has the potential to cause mesothelioma and other asbestos-related diseases.

What are the main causes of mesothelioma?

Mesothelioma is almost exclusively caused by exposure to asbestos. While there are other potential causes such as radiation, genetic predisposition, and certain viruses, they are extremely rare and are not considered significant causes of mesothelioma.

Veterans Support Team
Todd Gersten, MD PhotoReviewed by:Todd Gersten, MD

Double Board-Certified Oncologist and Hematologist

  • Fact-Checked
  • Editor

Todd Gersten, MD, is a double board-certified medical oncologist and hematologist specializing in general adult oncology and hematologic disease. He is a physician partner with the Florida Cancer Specialists and practices in Wellington, Florida.

Dr. Todd Gersten is an independently paid medical reviewer.

Christopher Dryfoos PhotoWritten by:

Contributing Author

Christopher Dryfoos is a journalist and member of the American Medical Writers Association (AMWA). As the grandson of the U.S. Navy’s first forensic pathologist, he aims to help veterans with mesothelioma access needed care.

  1. Agency for Toxic Substances and Disease Registry. CDC. “Health Effects of Asbestos.” Retrieved from: Accessed on April 2, 2024.
  2. Environmental Protection Agency. “Superfund Site: Libby Asbestos Site.” Retrieved from: Accessed on April 2, 2024.
  3. Mayo Clinic. “Asbestosis Symptoms and Causes.” Retrieved from: Accessed on April 2, 2024.
  4. Mayo Clinic. “Mesothelioma Causes.” Retrieved from: Accessed on April 2, 2024.
  5. U.S. Environmental Protection Agency. "Biden-Harris Administration finalizes ban on ongoing uses of asbestos to protect people from cancer." Retrieved from: Accessed on April 2, 2024.