Mesothelioma is a rare, aggressive, malignant cancer. The only known cause of mesothelioma is exposure to asbestos fibers. Though it is a naturally-occurring substance, most people with mesothelioma have had exposure to asbestos due to work in certain occupations.
What Causes Mesothelioma?
The only proven cause of mesothelioma is prior exposure to asbestos. Asbestos is a naturally occurring mineral composed of needle-like fibers. It occurs naturally in deposits throughout the U.S. and around the world and was widely used as insulation against extreme heat and as a fire retardant.
How Does Asbestos Exposure Occur?
Occupational Exposure
In most people, asbestos exposure occurred at work. It was used as insulation in industries with high-heat activities. The most common industries that caused asbestos exposure include:
- Steel Industry
- Ship Building
- Pipe Fitting
- Construction
- Auto Manufacturing
- Demolition
Secondhand Exposure
In some cases, exposure to asbestos may have been caused by asbestos fibers being transported into the home. Asbestos-contaminated clothing and hair would carry the dust into the living space where it was dispersed into the air.
Natural Exposure
Asbestos is a mineral that exists in natural deposits in parts of the U.S. Though exposure from asbestos deposits is rare, those living near those deposits may have been exposed to dust created from mining and road building as well as through run-off due to mining and other projects.
What is Asbestos?
Asbestos is a mineral found in certain types of rock. It occurs in deposits of one of six types of silicate minerals and there are two main types; Serpentine and Amphibole. Chrysotile asbestos is a subtype of the serpentine variety and has been used more frequently than other types but any sort of asbestos can result in mesothelioma development.
The mineral is comprised of tiny, needle-like fibers that are 1000 or more times smaller than a human hair. When broken down, the fibers become dust which still retains the needle-like quality. These dust particles, with the needle-like quality, may lodge in body tissues when inhaled or ingested.
Though Serpentine was more widely-used, it does not break into dust as easily and is easier for the body to expel. Though asbestos has been largely banned from public use, it was used for plaster, brake linings, fire barriers, pipe insulation, floor tiles, and gaskets. Many products still contain asbestos today and removal of these products can prove dangerous.
Amphibole asbestos has five main sub-types: actinolite, amosite, anthphylite, crocidolite and tremolite. Though amphibole asbestos was not as widely used in asbestos products, it is much more friable or breakable and more easily forms dust. Amphibole asbestos was used as a fire retardant in insulating boards, ceiling tiles, construction materials and other thermal insulation products.
How Does Mesothelioma Develop?
When asbestos-containing materials are disturbed, asbestos dust is released into the air. Even though it may appear only as powder, each particle is a small fiber of asbestos. Mesothelioma develops when:
- Disturbance of asbestos-containing asbestos causes dust to become airborne
- Airborne asbestos fibers are inhaled or ingested as dust
- These fibers lodge in the protective linings of certain organs including the lungs (pleura), abdomen (peritoneum), heart (pericardial sac), or testicles (testicular sac).
- The fibers which have lodged in the mesothelial linings, inflame and irritate the mesothelial cells. Over time, genetic mutations may cause the cells to begin dividing uncontrollably.
- The uncontrolled cellular growth results in the formation of tumors, which may become larger and spread to lymph nodes and other areas of the body.
Mesothelioma is caused by mutations of cellular DNA which may trigger cells of the mesothelium to begin dividing much faster than normal. This results in the formation of tumors of mesothelial tissues or mesothelioma which is a malignant cancer.
Each cell of the body is programmed by the cellular DNA to divide only at certain times. Each type of tissue contains cells that divide at different rates under normal circumstances. For example, skin cells are constantly dividing to replace cells that have sloughed off and blood cells divide frequently to replace old cells which can no longer function. Bone cells only divide in case of needed growth or injury and otherwise reproduce quite slowly and some cells rarely or never reproduce such as the tissue of certain organs or tissues like nerve tissue and the brain.
Asbestos may take 20 to 50 years to cause the genetic mutations required for mesothelioma to develop, though in some cases, the cancer emerges more quickly. Symptoms may develop slowly over a long period of time, or may emerge suddenly and many of the symptoms may be mistaken as other illnesses such as a cold, pneumonia, heart disease or other disorder. Symptoms that are similar to other illnesses can include chronic cough, chest pain, difficulty breathing, swelling and shortness of breath.
Men or more likely to get and be diagnosed with mesothelioma as work in asbestos-related occupations was more likely to be performed by men when asbestos was still in widespread use. Women, however, may have been exposed but many people, both men and women, do not even know that they may be at risk for developing mesothelioma.
Asbestos Use and Production
Russia, China, Brazil and Kazakhstan still produce bulk asbestos and it though it is widely known to cause cancer, it continues to be used in products and insulation throughout India, Indonesia, China, Russia and Brazil. Asbestos deposits are known to exist in North America, however asbestos mines in the U.S. and Canada have been closed and the substance has been largely banned in the U.S., Europe, and much of the developed world.
The Environmental Protection Agency began requesting lists from American companies of their products containing asbestos in 1981, which eventually led to the Asbestos Information Act of 1988. Although asbestos is still used in the United States, this law requires manufacturers of asbestos products to submit detailed information on their products to the EPA.
Occupational Exposure
Occupational exposure is the most common cause of mesothelioma development. These people were exposed at work and are at higher risk for developing mesothelioma. As the disease may take 20 to50 years to appear, even though only 3,000 new cases emerge each year, many more are still at risk including those who worked with materials containing asbestos such as:
- Insulation
- Roofing, flooring and other construction materials
- Automotive parts such as brake pads, clutches and gaskets
- Pipes and pipe fittings
- Electrical wiring
- Heating and air duct materials
- Paint
- Materials where cutting or sanding was required
Home and Business Construction
Buildings constructed before 1975 are likely to contain asbestos insulation and remodeling of these older buildings or homes pose substantial risk. In addition, because asbestos is now commonly known to cause cancer and asbestosis (another health condition related to asbestos), many owners wish to rid the building of asbestos.
Removal of asbestos in buildings or in other types of construction may disturb asbestos dust and present a significant health hazard. Most commonly, rather than removing the insulation or other products, asbestos “containment” is performed to seal the substance in place, however, the asbestos removal and recovery industry still poses significant risk to workers and those present in the area.
Ship Building
Asbestos use underwent significant increase during World War II due to ship, aircraft and other vehicle production. The insulator and fire resistant properties of asbestos made it an effective, convenient and cost-efficient material for many industrial applications. Because of its widespread use in the military, Veterans are at high risk.
Automotive Manufacturing and Work
Asbestos was a common constituent of automotive parts, particularly brake system, clutch systems and areas needing insulation. Those involved in automotive manufacturing during widespread asbestos use, including the manufacture of automotive parts may have been at risk. Work on old cars may present a risk of asbestos exposure. Automotive parts such as brake pads, clutches, gaskets and insulation may contain asbestos, posing a risk when rebuilding or restoring older vehicles.
Secondary Exposure
Some of those diagnosed with mesothelioma do not recall when they were exposed. Others may do not realize it at all. Secondary exposure may be the cause of many of these cases.
Spouses or other family members of construction and factory workers may have become exposed when workers returned to the home, covered in asbestos dust. The fibers may have been on the skin, hair and covering clothing and boots. Spouses or family members may have been exposed from something as simple as doing laundry.
Secondary exposure may occur in the work setting as well. Office workers in asbestos-related industries may have been exposed to dust that traveled through inadequate ventilation systems or who spent break-time or congregated with other asbestos workers.
Asbestos exposure may also have occurred in communities where asbestos-related industry facilities were placed. These factories, mines, shipyards and other industrial establishments could have released asbestos-laden dust or particles into the air or water supply. Several mine operations at locations such as Libby, Montana and Coalinga, California have been shown to have resulted in secondary exposure through mine runoffs and water supply contamination
Who is at Risk?
The major risk factors involved in determining risk of mesothelioma development include:
- Occupation
- Duration or Frequency of Exposure
- Protective Equipment
- Previous Lung Disease
- Breathing Rate during Exposure
- Weather during Exposure
- Concentration of Exposure
Who is Most at Risk
The people who are most at risk for developing mesothelioma are largely men, particularly those over the age of 65, and veterans. More than 75% of mesothelioma deaths occur in men, mainly between the ages of 50 and 70. Despite the normal latency, some younger people may develop mesothelioma as early as during their 20’s if exposure occurred at a young age.
Currently, 9-11 workers are considered to be at high risk as well but mesothelioma development will likely not be known for several years.
People who are most at risk for mesothelioma include: men, those over 65 years of age and military veterans. Over 75 percent of people who die from mesothelioma are men. This makes sense as most asbestos exposure occurred in construction related occupations historically dominated by men.
Smoking increases the risk of lung cancer development but no direct link has been shown between smoking and mesothelioma development. Despite the lack of connection, carcinogens present in cigarette smoke may decrease a patient’s overall health, particularly lung health and may increase the chance of developing cancer.
What action should I take?
If you were exposed to asbestos, you should be aware of the symptoms. You should also inform you physicians of previous exposure so that any symptoms will not be mistaken for another disorder and will be immediately investigated.
If you receive a mesothelioma diagnosis, you should seek a second opinion from a mesothelioma specialist who can confirm you diagnosis and offer the best treatment options.
Mesothelioma victims may have recourse in compensation for the deadly and costly disease. Several victims have received multimillion dollar settlements and a fund has been set up to aid victims with costs related to mesothelioma. Each case is unique and should be evaluated by a legal specialist.
