We know that mesothelioma is a deadly form of cancer that moves quickly once symptoms start to appear. It affects the lining (or mesothelium) of a variety of organs, most commonly the lungs. But, what causes mesothelioma to crop up in the first place? We know that answer to that question, too.

Exposure to asbestos is the primary cause of mesothelioma, accounting for over 90% of all cases. Asbestos is a natural mineral that was used in a fibrous form in many products throughout the early 20th century and, despite heavy regulation, is still used in some products today. It contains natural fire- and heat-resistant qualities making it ideal for building materials. Unfortunately, it’s also a carcinogen (cancer-causing agent).

In addition to being one of the main mesothelioma causes, asbestos can also produce a wide variety of other illnesses and ailments.

These other diseases and conditions include:

  • Lung cancer
  • Laryngeal cancer
  • Ovarian cancer
  • Asbestosis (scarring and inflammation of lung tissue)
  • Pleural effusion (fluid buildup around the lungs)
  • Pleuritis (inflammation of the pleura or the lining of the lungs)
  • Atelectasis (scarring and inflammation that cause the lining of the lungs to fold and impede normal breathing)
  • Pleural plaques (thickening that occurs in the lining of the lungs)

Some of these conditions, like pleuritis and pleural effusion, can present as symptoms of mesothelioma. While exposure to asbestos today is very limited, the disease takes between 10 and 50 years (usually around 30 to 40) to begin showing symptoms.

So, it is not unheard of for exposure to the substance in the 1970s to produce a mesothelioma diagnosis in the 2010s.

History of Asbestos Use

Before the destructive characteristics of asbestos were fully understood, the link between exposure to the substance and prominent lung issues was well-documented. Asbestos miners in the early 1900s were at a far greater risk of developing ultimately fatal lung complications than many other people. The disease didn’t have a name then, but the issues were apparent.

Autopsies performed on those who had worked closely with asbestos showed a plethora of asbestos fibers in the lungs. Despite this, asbestos production increased rapidly. In 1910, the total amount of worldwide asbestos for commercial use reached 109,000 metric tons. Studies in the 1930s began identifying the connection between exposure to asbestos and mesothelioma. More studies in the 1960s provided definitive proof of the link.

Unfortunately, the asbestos industry was huge even into the 1960s and 1970s. Mining of the substance peaked in those decades with the United States accounting for 803,000 tons by 1973. Over 4 million metric tons of the substance were being produced annually throughout the world at the time. An estimated 27 million individuals were exposed to asbestos between the 1940s and the 1970s.

As it became clearer and clearer that asbestos was extremely bad for workers’ health, many nations in the developed world began curbing its usage. In 1971, the U.S. Occupational Safety and Health Administration (OSHA) began regulating the mineral. Throughout the following decades, the amount of permissible asbestos was reduced drastically, and the asbestos industry began winding down.

In 2002, the last asbestos mining operation in the United States closed down. Even so, it is still legal to import products that contain asbestos. Although many materials don’t have any asbestos particles in them anymore, there are still some that remain in older buildings and other products.

Risk of Mesothelioma for Asbestos Workers in the United States is 8% to 13%

Products that used to or still do contain asbestos include:

  • Insulation
  • Concrete
  • Cement
  • Drywall
  • Flooring
  • Roofing
  • Gaskets
  • Paints
  • Sealants
  • Potting soil
  • Mattresses
  • Electrical appliances
  • Electrical wiring
  • Brake pads
  • Fireproof clothing

Clearly, there was a historical value to the substance. The unfortunate thing is that many companies traded their employees’ lives for fireproof material.

But how does asbestos exposure actually cause mesothelioma?

How Asbestos Causes Mesothelioma

When it comes to mesothelioma, asbestos exposure is the main cause. But what is it about asbestos that produces such a harmful disease? Under most circumstances, airborne asbestos fibers are inhaled by an individual.

Asbestos fibers can remain airborne for as long as an hour, making them particularly dangerous. The individual fibers then get lodged in the lining (or mesothelium) of the lungs, abdomen, or heart.

The body has a mechanism to remove foreign objects like asbestos fibers, but long-term, high-density exposure to asbestos increases the chances of the substance staying put. The fibers act as an irritant to the mesothelium, often causing inflammation.

The presence of the fibers also causes DNA mutations first by interfering with cell division and later by causing mesothelial cells to produce oxygen and nitrogen as a mutagenic response. All of this can eventually cause the formation of tumors in the mesothelium.

Other ways that asbestos can affect the body involve ingestion or travel through the lymph nodes. Pleural mesothelioma (occurring in the lining of the lungs) is the most common form of the disease and is usually caused by inhalation.

Peritoneal mesothelioma (occurring the lining of the abdominal cavity) can be caused by ingesting asbestos. This usually happens when an individual coughs the substance up out of their lungs and inadvertently swallows some of the residues.

Pericardial mesothelioma (occurring in the lining of the heart) can be caused by asbestos traveling through the lymph nodes.

Who is Most At Risk of Asbestos Exposure

Most exposure to asbestos occurs on the job. There are many individuals who were and still are at risk of being exposed to the substance while working. In fact, one estimate suggests that there are over 75 different occupations in which asbestos exposure can occur. Of course, some workers are more likely to be exposed than others.

Let’s look at some of the most common occupations for asbestos exposure below.

Construction Workers

Construction workers of all varieties are at high risk for asbestos exposure. As noted above, asbestos was frequently used in numerous building materials between the 1900s and 1970s. Many of those materials have now been banned, but that doesn’t mean they can’t be found in older buildings. Homes or other buildings that haven’t been updated since the 1970s or earlier can have a variety of asbestos-containing products (like insulation, drywall, or paint).

This makes remodels, renovations, and even demolitions particularly worrisome. Anyone who works or worked in construction can still be at risk of exposure and, eventually, developing mesothelioma.

Some construction occupations include:

  • Insulation workers
  • Drywall workers
  • Pipefitters
  • Roofers
  • Plasterers
  • General contractors
  • Electricians
  • Carpenters
  • Plumbers

Essentially, anyone who has worked at a construction site or during a renovation is at risk for exposure to asbestos. New construction sites are not as risky as older ones, however. In the United States, OSHA has drastically limited the amount of acceptable exposure to asbestos on a job site.

New building materials also do not contain the substance or, if they do, the asbestos within them cannot become airborne.

Shipyard Workers

In the past, ships were often constructed using a wide variety of asbestos products. This was obviously due to the fact that a fire on a ship could prove disastrous for its crew, and asbestos was fire-resistant. Asbestos was also used to avoid corrosion and provide good insulation on ships.

Unfortunately, anyone who worked at shipyards, on the ships themselves, or during the construction of ships was at risk of exposure. In this day and age, asbestos is rare in the construction of marine vessels, but a lot of the damage has already been done.

Many individuals who have incurred a mesothelioma diagnosis are U.S. Navy veterans. It was common, particularly during World War II and the Vietnam War for Navy officers to be exposed to asbestos. Aircraft carriers, battleships, cruisers, submarines, and a variety of other vessels all contained asbestos to some degree.

Industrial Workers

A wide range of industrial workers could have been exposed to asbestos at some point during their work. Most industrial plants in the United States contained large quantities of asbestos either in the building materials or in the equipment materials. Spray-on insulation coating that contained asbestos as an ingredient was often used for fire resistance on heated surfaces.

Asbestos insulation was also used on equipment like autoclaves, hot engine heaters, and gas valves.

Other asbestos-containing products and equipment that industrial workers may have used include:

  • Cement
  • Caulking compounds
  • Pipe wrappings and insulation
  • Plastics
  • Sheet backings made of vinyl

Any worker who engaged in smelting, welding, soldering, compression molding, metal extraction, and numerous other activities could have been exposed to asbestos, as well. In many industrial plants, airborne asbestos would be prevalent because of the lack of proper ventilation systems.

Again, industrial plants are safer now as far as asbestos exposure is concerned, but if you worked in one of these plants in the 1970s or earlier, you were at high risk of contamination.

Power Plant Workers

Power plants were another workplace in which asbestos was prevalent. Because most of the machinery runs hot, asbestos insulation was used to avoid fires and unmanageably high temperatures. Power plants that haven’t been fully updated since the 1970s are likely to contain a large amount of asbestos in the machinery and various products.

If power plants were updated, the employees who engaged in that renovation were likely exposed to higher rates of asbestos. In all likelihood, they had to cut through building materials or remove products that contained high amounts of the substance.

Like industrial plants, power plants often had high amounts of airborne asbestos at any given time because of the lack of high-quality ventilation systems.


Firefighters are also at high risk of toxic asbestos contamination. In fact, firefighters are at a much higher risk because asbestos that catches fire usually enters the air at much higher concentrations. Back when many buildings contained large amounts of asbestos material, the air around burning buildings was usually more toxic. The rates of diseases like mesothelioma, lung cancer, and asbestosis are very high in former firefighters.

Secondhand Exposure

In some cases, secondhand exposure to asbestos can cause mesothelioma later on in life. This usually happens to people who live with someone who works or worked with asbestos frequently. There are many documented cases of wives who used to wash their husband’s work clothes who later ended up with a mesothelioma diagnosis.

Children of people who worked with asbestos routinely are also at a higher risk of developing mesothelioma.

Secondhand exposure can also occur for people who live close to areas with high levels of asbestos in the air. Individuals who live or work near power plants, industrial plants, oil refineries, shipyards, and asbestos mines are at a higher risk.

Other Risk Factors

There are numerous other risk factors that can aid in the development of or outright cause asbestos. Still, for mesothelioma, asbestos exposure is the primary way that the disease develops.

Some other components that can contribute to that diagnosis or are mesothelioma causes in and of themselves include:


Some studies have estimated that smoking in conjunction with asbestos exposure can increase the likelihood of mesothelioma by 50%

High aspect ratio nanoparticles (HARNs)

HARNs (and more specifically, carbon nanotubes) have been linked to the incidence of mesothelioma, but more research is required to be conclusive


Zeolites (and particularly erionite) are silicate materials that are similar to asbestos and have been known to cause mesothelioma

Simian virus 40 (SV40)

This virus has been linked to an increased likelihood of mesothelioma, but it has not been identified as a cause.

Other factors include how long an individual was exposed to asbestos and how much of it in total they were exposed to. Mesothelioma also most commonly affects men, mostly because asbestos is found more often in male-dominated fields.

Avoiding Asbestos Exposure

So what are the best ways to avoid asbestos exposure?

For the most part, asbestos has been removed from job sites, products, and buildings that once contained the mineral. Still, asbestos-containing products haven’t been removed from every aspect of life. If you are moving into a new house that was built prior to the 1980s, be sure to have an asbestos removal specialist look at the building materials.

It’s entirely possible that some asbestos remains. Only an asbestos removal specialist can accurately identify and get rid of the asbestos in buildings.

If you are not planning on renovating the house, then the asbestos in the house should not cause any problems unless you disturb it in some way. Still, it’s probably better to be safe than sorry and just eliminate the risk entirely.

If you believe there is a chance of asbestos exposure at your workplace, you should never bring your work clothes home as it can increase your own exposure and subject your family to asbestos. Most workplaces with possible asbestos should provide on-site showers and laundry to avoid exposure. They should also offer respirators that are rated for blocking asbestos.

In some cases, businesses do not completely follow OSHA safety guidelines for asbestos. If you believe that your employer is violating OSHA guidelines, it’s vital to contact the agency and file a complaint.