The Dangers of Asbestos Exposure

We often hear that asbestos is dangerous, but what does that mean? What health conditions are caused by exposure, and how much exposure is necessary for asbestos to be a danger?

Asbestos removal site with warning sign and warning tape
SamBurt / Getty Images

Why Asbestos Is Dangerous

Exposure to asbestos dust and fibers can result in cancer, lung disease, as well as other conditions. Unfortunately, there is no known level of exposure that is considered safe. While the use of asbestos has been banned in the United States, exposure is still common. There are exceptions to the ban and asbestos is still present in many older buildings and homes. In fact, asbestos-related health conditions continue to increase worldwide. People most at risk include those who are exposed on the job, but those who decide to take on do-it-yourself projects in homes containing asbestos insulation may also be at risk.

Before describing asbestos-related health conditions, let's define a few terms. The pleura are membranes that surround and protect the lungs. Another term that is often referred to is the mesothelium. The mesothelium is the protective lining that surrounds organs in the chest and abdomen and is divided into three regions: The pleura (which surrounds the lungs as noted above), the pericardium (which surrounds the heart), and the peritoneal mesothelium (the protective tissue that surrounds the organs in the abdomen).

Cancers Caused by Asbestos Exposure

Activists have done a good job in making the public and policymakers aware of the risk of one type of lung cancer—mesothelioma—caused by asbestos exposure. For those who question whether their efforts to raise their voice and ask for change when their health is at risk, this is an excellent example of how individuals can indeed make a difference.

There have been discussions about different fiber sizes and forms having different risks, but for the purpose of this discussion, we’ll look at the overall picture. Cancers caused or thought to be caused by asbestos include:

  • Malignant mesothelioma: Mesothelioma is a cancer the begins in any of the areas where mesothelium is found as noted above, but commonly occurs in the pleura (the membranes around the lungs.) It is an aggressive cancer, with only 7% to 18% of people surviving five years beyond their diagnosis.
  • Lung cancer: The risk of lung cancers other than mesothelioma are also increased by exposure. Both non-small cell lung cancer and small cell lung cancer risks are increased.
  • Ovarian cancer: Less well known is the increased risk of ovarian cancer. In a review of studies to date, it was thought that occupational exposure to asbestos increased ovarian cancer risk by around 70%.
  • Other cancers: Studies thus far have been mixed, and it’s uncertain whether or not asbestos exposure increases the risk of laryngeal cancer (cancer of the throat) and colorectal cancer.

Other Medical Conditions Caused by Asbestos Exposure

Less well known, but an even greater problem is lung disease related to asbestos exposure. Some of these conditions include:

  • Asbestosis: Asbestosis is a condition in which pulmonary fibrosis (scarring) occurs due to asbestos exposure. This condition, in addition to causing symptoms on its own, further increases the risk of lung cancer.
  • Pleural plaques and pleural thickening: Pleural plaques and thickening occur when there are changes in the membranes surrounding the lung.
  • Pleural effusions: Some people exposed to asbestos develop a build-up of fluid between the membranes that line the lungs. This has been called benign asbestos-related pleural effusions (BAPEs).

What Level of Exposure Is Dangerous?

A common question is, "how much asbestos do I need to be exposed to be at risk?" The answer is that there is no level of asbestos exposure that is safe. But a few studies have helped to answer the details in that question.

One study was done looking primarily at people with asbestosis. This was a large study that compared almost 2,400 male insulators (who were thus exposed to asbestos) to a group of over 54,000 people who had not had such exposure. Overall, lung cancer was responsible for the death of 19% of the insulators. The risk of death varied considerably depending upon exposure alone, the development of asbestosis, and the co-risk factor of smoking. Specific findings were found in the following sub-groups:

  • Asbestos exposure in non-smokers: There were 3.6 times as many cases of lung cancer.
  • Asbestosis in non-smokers: The risk was 7.4 times that of the general population.
  • Smoking without asbestos exposure: This risk of lung cancer in those who smoke was 10.3 times that of the general population in this study.
  • Asbestos exposure plus smoking: Exposure to asbestos combined with smoking made the likelihood of lung cancer 14.4 times the average.
  • Asbestos exposure, asbestosis, plus smoking: If people were exposed to asbestos, developed asbestosis, plus smoked, the results were grave. The risk of lung cancer was 36.8 times higher than the general population.

We can look at asbestos exposure in another way to get the big picture and to further outline the problem for those in the industry. It’s been estimated that 170 tons of produced and consumed of asbestos correlate with one death from mesothelioma.

An important question is how important the length of exposure is—in other words, are those who are exposed for 30 years more likely to be affected than those exposed for five years? We don't have studies that outline the exact risk over time, but it's likely that the longer someone is exposed, the greater their risk of asbestos-related disease.

What Makes Asbestos Dangerous?

How asbestos damages the body is likely a combination of fiber type and size, lung clearance, and genetics. A few theories have emerged. In one, it’s thought that asbestos fibers may directly have a toxic effect on the cells lining the lungs, causing inflammation which leads to scarring. Part of the damage may also relate to the body’s reaction to the presence of asbestos fibers, as the body secretes inflammatory substances such as cytokines and growth factors in response to the foreign substance. Evidence also suggests that the presence of asbestos causes direct DNA damage to cells, which in turn can result in cell abnormalities and cancer.

Safety and Protection

For workers who are exposed to asbestos, there are rules in place for protecting yourself. Familiarize yourself with safety precautions, as well as your rights as an employee. Here are a few sources to get you started:

For those concerned about asbestos in their homes, or who are considering a home remodeling project, the Consumer Safety Commission provides information on where it is found, what should be done about asbestos in your home, and how to manage asbestos problems.

What to Do If You’ve Been Exposed

There isn’t currently a lung cancer screening test recommended for people who have been exposed to asbestos, as there is for smokers, but it may be worth talking to your healthcare provider. A study done in 2007 suggested that low-dose CT screening for asbestos workers may be at least as useful in detecting lung cancer in the early stages as it is for heavy smokers. That’s significant considering that later guidelines in 2013 found that screening people with a 30 pack-year history of smoking who were between the ages of 55 and 74 could reduce lung cancer deaths by 20%. Certainly, if you have been a smoker in addition to being exposed to asbestos, a conversation with your doctor is a good idea.

A 2017 study found that spirometry may be an excellent tool for screening for lung cancer in those who have been exposed to asbestos. In fact, based on the results of the study, researchers recommended that anyone who has been exposed to asbestos should have spirometry done and have it repeated every three years.

The Agency for Toxic Substances and Disease Registry (ATSDR) has developed screening guidelines for asbestos-related disease including cancer as well as lung conditions. These guidelines recommend that you see a v who is familiar with asbestos-related disease. (We can’t emphasize how important this is as some healthcare providers rarely work with people exposed to asbestos.) Another problem with those who have been exposed to asbestos is that CT screening frequently reveals “false positive” tests—meaning that something may appear abnormal when it is indeed okay. For example, in one study, over half of asbestos workers had at least one abnormality noted on a CT scan.

In addition to screening, spirometry, and asbestos protection, perhaps the most important thing anyone can do is refrain from smoking. There are also other things you can do that may lower your risk.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. United States Department of Labor. Occupational Safety and Health Administration. Asbestos.

  2. Prazakova S, Thomas PS, Sandrini A, Yates DH. Asbestos and the lung in the 21st century: an update. Clin Respir J. 2014 Jan;8(1):1-10. doi:10.1111/crj.12028

  3. American Cancer Society. Survival rates for Mesothelioma.

  4. National Cancer Institute. Asbestos exposure and cancer risk.

  5. Camargo MC, Stayner LT, Straif K, et al. Occupational exposure to asbestos and ovarian cancer: a meta-analysis. Environ Health Perspect. 2011 Sep;119(9):1211-7. doi:10.1289/ehp.1003283

  6. Markowitz SB, Levin SM, Miller A, Morabia A. Asbestos, asbestosis, smoking, and lung cancer. New findings from the North American insulator cohort. Am J Respir Crit Care Med. 2013 Jul 1;188(1):90-6. doi:10.1164/rccm.201302-0257OC

  7. Takala J. Eliminating occupational cancerInd Health. 2015;53(4):307-309. doi:10.2486/indhealth.53-307

  8. Liu G, Cheresh P, Kamp D. Molecular Basis of Asbestos-Induced Lung Disease

     Annual Review of Pathology: Mechanisms of Disease 2013 8:1, 161-187

  9. Fasola G, Belvedere O, Aita M, et al. Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002). Oncologist. 2007 Oct;12(10):1215-24. doi: 10.1634/theoncologist.12-10-1215

  10. Wender R, Fontham ET, Barrera E, et al. American Cancer Society lung cancer screening guidelines. CA Cancer J Clin. 2013 Mar-Apr;63(2):107-17. doi:10.3322/caac.21172

  11. Świątkowska B, Szeszenia-Dąbrowska N. Spirometry: a predictor of lung cancer among asbestos workers. Inhal Toxicol. 2017 Jan;29(1):18-22. doi:10.1080/08958378.2016.1272652

Additional Reading

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."