Mesothelioma Causes

Asbestos exposure is the only confirmed cause of pleural mesothelioma. When asbestos fibers are inhaled, they travel through the body to the pleura (lining of the lungs) where they cause irritation and permanent scarring of healthy mesothelial cells. After decades of cellular damage, cancerous cells begin to grow and divide, eventually forming mesothelioma tumors. Veterans and those who worked with asbestos-based products are most likely to develop mesothelioma.

What Causes Mesothelioma?

Mesothelioma is caused by exposure to asbestos, a naturally-occurring mineral made up of microscopic but strong, heat-resistant fibers.

Causes of Mesothelioma Video Thumbnail

Registered Nurse Amy Fair discusses how exposure to asbestos can cause mesothelioma. View Transcript.

Duration: 1 min 06 sec

What are the causes of mesothelioma?

Many times after being diagnosed with mesothelioma your physician may ask you if you have been exposed to asbestos. Asbestos is a causative factor for mesothelioma. Some of the imaging studies may show underlying pleural plaques which are indicated that they have been around asbestos and may show underlying asbestosis.

The risk factors for developing mesothelioma are working around asbestos-related products or being indirectly around those products such as secondhand exposures that are seen with wives that launder their loved ones’ clothes and have asbestos dust on them. So direct asbestos exposure, as well as indirect asbestos exposure, can be causative factors for mesothelioma.

If you have symptoms of mesothelioma or any asbestos-related disease, it’s important that you inform your doctor of your asbestos exposure so that appropriate testing can be done.

How Does Asbestos Cause Mesothelioma?

Mesothelioma may develop after someone inhales or swallows asbestos fibers.

1. Exposure

Asbestos fibers are sent into the air through mining, building renovations, automobile or ship maintenance, normal wear-and-tear of asbestos products, etc.

2. Entry

If inhaled, these fibers can travel through small air passages and get stuck in the lining of the lungs (pleura). The fibers may also reach the lining of the abdomen (peritoneum) if swallowed.

3. Irritation

Once inside the body, the fibers inflame and scar healthy tissue. Asbestos fibers are so small and strong that the body can never remove them or break them down.

4. Cancer Growth

Over 20-50 years, the fibers cause DNA damage to healthy cells, which leads to uncontrolled cell growth. Mesothelioma tumors form as cancerous cells grow at an out-of-control rate.

Although exposure to asbestos is the only known cause of mesothelioma at this time, scientists are studying how other risk factors like genetic history may play a role.

Asbestos Exposure Levels and Mesothelioma

According to the National Cancer Institute (NCI), higher levels of asbestos exposure increase your risk of developing malignant mesothelioma.

However, the organization also warns that there is no safe level of asbestos exposure. Some people have even developed mesothelioma after only one instance of asbestos exposure, according to the National Organization for Rare Disorders (NORD).

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Where Asbestos Exposure Occurs

Those who serve in the U.S. military or in industrial occupations like construction are at a higher risk of asbestos exposure. Some people can be also exposed to asbestos in their homes or in natural environments.

Occupational Asbestos Exposure

NORD reports that occupational asbestos exposure is the most common way people are exposed to asbestos.

Over 27 million people were exposed to asbestos at their jobs between 1940 and 1979, according to the Agency for Toxic Substances and Diseases Registry (ATSDR).

Worksites with potential asbestos exposure risk include:

  • Automobile assembly plants
  • Chemical plants
  • Coal and asbestos mines
  • Construction sites
  • Mining sites
  • Power plants
  • Shipyards
  • Steel mills

While asbestos use was greatly restricted in the 1980s, it has not been completely banned, meaning some of these work sites still come with a risk of exposure today.

Military Asbestos Exposure

Asbestos was heavily used by the military to keep its ships, vehicles, and bases flame-resistant and durable. As a result, U.S. veterans with mesothelioma account for over 30% of all cases.

Navy veterans had the highest risk of exposure out of all military branches because they used more asbestos than any other branch.

Secondhand Asbestos Exposure

Family members and loved ones may also be exposed to asbestos indirectly if a worker carried the fibers home on their clothes, skin, and hair. This is called secondhand asbestos exposure.

“There is some evidence that family members of workers heavily exposed to asbestos face an increased risk of developing mesothelioma.”

– National Cancer Institute

Environmental Asbestos Exposure

According to the NCI, everyone experiences some level of asbestos exposure, as small amounts of it naturally get into air, water, and soil. This type of exposure rarely makes people ill.

However, there are a few places where asbestos exists in unusually high levels, putting people in great danger of environmental exposure. For example, living close to mines or naturally occurring asbestos deposits may increase the risk of mesothelioma.

Mesothelioma Risk Factors

A risk factor is anything that affects a person’s chance of developing a disease or cancer. It is not clear why some people are more at risk for mesothelioma than others, but the following factors may be involved.

Factors that may increase the risk of mesothelioma include:

  • History of asbestos exposure: If you worked around asbestos or lived with someone who did, you have a greater cancer risk. As previously mentioned, higher amounts of exposure may make it more likely that you’ll get sick.
  • Family history of mesothelioma: If a relative developed this deadly cancer, you may also be at risk through secondhand exposure. You also may have inherited a genetic mutation.
  • Genetic mutation: According to the NCI, a mutation in the BAP1 gene can increase the chances of developing mesothelioma tumors.

Preventing Mesothelioma

Complete mesothelioma prevention is not possible, however, there are steps you can take to help lower your risks.

Know the Dangers

Learn if you may come into contact with asbestos while you work. For example, some commercial and public buildings still contain asbestos, which may pose a risk if the building is damaged or being renovated.

If you worked in a high-risk job before the dangers of asbestos became well-known, talk to your doctor about getting tested for mesothelioma or other conditions.

Follow Safety Regulations

If you work around asbestos, follow all guidelines in place to reduce the risk of exposure. Further, showering and changing clothes before leaving work may help protect loved ones from secondhand exposure.

Take Precautions in the Home

Older homes may still contain asbestos, so make sure they are inspected. If the asbestos in your home poses a threat, consult a professional to have it removed. Do not handle asbestos yourself.

Speak Up

If you are concerned about asbestos in the workplace or your home, get in touch with your employer or landlord. They can take steps to seal or remove asbestos products to help keep you safe.

Advocate for an Asbestos Ban

Until asbestos is totally banned in the U.S., it will continue to pose a threat. You can advocate for an asbestos ban by signing petitions that urge the Environmental Protection Agency (EPA) to take action or by calling your local congressman to support laws that ban asbestos.

Mesothelioma Causes: Next Steps

While asbestos is now known to cause mesothelioma, millions of people were exposed without knowing the risks. For decades, manufacturers of asbestos-containing products hid evidence of the mineral’s toxic effects from the public.

If you believe your mesothelioma was caused by asbestos exposure, you can seek financial compensation from these manufacturers today. This can help you cover costs of treatment and other expenses.

Download our free mesothelioma guide to learn more.

Reviewed by:Dr. Mark Levin

Certified Oncologist and Hematologist

  • Fact-Checked
  • Editor

Mark Levin, MD has nearly 30 years of experience in academic and community hematology and oncology. In addition to serving as Chief or Director at four different teaching institutions throughout his life, he is also still a practicing clinician, has taught and designed formal education programs, and has authored numerous publications in various fields related to hematology and oncology.

Dr. Mark Levin is an independently paid medical reviewer.

Mesothelioma Hope was founded by a team of advocates to educate people about this aggressive form of cancer. Mesothelioma affects thousands of people each year. We help give hope to those impacted by mesothelioma.

7 references
  1. Agency for Toxic Substances and Diseases Registry. (n.d.). Environmental Health and Medicine Education. Retrieved September 18, 2020, from
  2. Mayo Clinic staff. (2019). Mesothelioma. Retrieved March 2, 2020, from
  3. National Cancer Society. (2018). What Causes Malignant Mesothelioma? Retrieved March 2, 2020, from
  4. National Cancer Institute. (2017). Asbestos Exposure and Cancer Risk. Retrieved March 2, 2020, from
  5. National Organization for Rare Disorders. (2017). Mesothelioma. Retrieved March 2, 2020, from
  6. United States Department of Labor: Occupational Safety and Health Administration. (1995). 1926.1101 App H - Substance Technical Information for Asbestos - Non-Mandatory. Retrieved March 2, 2020, from
  7. U.S National Library of Medicine. (2020, August 17). BAP1 tumor predisposition syndrome - Genetics Home Reference - NIH. Retrieved September 18, 2020, from

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