Mesothelioma is a rare and aggressive cancer that develops in the thin lining covering many internal organs, such as the lungs, abdomen, and heart. This disease is almost always linked to exposure to asbestos, a naturally occurring mineral fiber. The disease typically manifests many years after initial contact with these fibers.
Asbestos as the Primary Cause
Asbestos refers to a group of naturally occurring fibrous minerals. These minerals are composed of microscopic fibrils. When materials containing asbestos are disturbed, these tiny fibrils can be released into the air.
Inhaling these microscopic asbestos fibers is the primary way they enter the body. Once inside, these durable fibers can become lodged in the mesothelium, the protective lining of organs. Over time, these trapped fibers can cause irritation, inflammation, and scarring in the tissue. This prolonged cellular damage and chronic irritation can lead to genetic changes and the development of cancerous cells.
Common Exposure Pathways
Asbestos exposure can occur through several pathways. Occupational exposure affects workers in industries like construction, shipbuilding, insulation, and mining. Workers involved in demolition or renovation of older buildings, especially those built before the 1980s, face risks due to asbestos in materials like insulation, floor tiles, and roofing.
Secondary, or “take-home,” exposure occurs when asbestos fibers are carried from a worksite on a worker’s clothing, skin, or hair. Historically, family members who laundered contaminated work clothes faced this risk, leading to diagnoses in people who never directly worked with asbestos.
Environmental exposure impacts individuals living near natural asbestos deposits, mines, or manufacturing plants. Natural weathering or human activities like landscaping can release fibers. Some consumer products, such as certain talcum powders, have also been found to be contaminated.
Factors Affecting Risk Level
Several variables influence the likelihood of developing mesothelioma after asbestos exposure. The “dose,” or total amount of asbestos fibers inhaled, plays a significant role; a higher cumulative dose increases the risk. The “duration” of exposure, or length of time in contact with asbestos, also contributes to risk.
The type of asbestos fibers encountered also influences risk, with amphibole asbestos varieties, such as crocidolite and amosite, considered more potent in causing mesothelioma than chrysotile asbestos. However, all forms of asbestos are recognized as carcinogenic.
Mesothelioma has a long latency period, a time gap between initial asbestos exposure and symptom onset, which can range from 15 to 70 years, typically peaking between 30 to 40 years. While exposure to asbestos is the primary cause, not everyone exposed will develop the disease, suggesting that individual susceptibility, possibly influenced by genetic factors like a mutation in the BAP1 gene, may also play a part.
Minimizing Exposure and Risk
Reducing or preventing asbestos exposure involves a combination of regulatory measures, safe handling practices, and personal precautions. Government bodies, such as the Occupational Safety and Health Administration (OSHA) in the workplace and the Environmental Protection Agency (EPA) for environmental protection, establish standards to limit asbestos exposure. These regulations guide safe work practices and the disposal of asbestos-containing materials.
When asbestos-containing materials are present in buildings, it is generally recommended to leave them undisturbed if they are in good condition, as fibers are less likely to be released. If disturbance is necessary, such as during renovations, repairs, or demolition, professional asbestos abatement companies should be engaged. These specialists are trained in techniques that prevent fiber release, including sealing off work areas and using specialized vacuum cleaners.
Workers involved in asbestos handling must use appropriate personal protective equipment (PPE) to minimize exposure. This typically includes disposable coveralls made of synthetic fabrics, thick gloves, and boot covers to prevent fibers from adhering to clothing or skin. Respiratory protection is particularly important, requiring at least a P2-rated particulate face mask, or more often, a half or full facepiece respirator with high-efficiency particulate air (HEPA) filters, to prevent inhalation of airborne fibers. Used PPE must be disposed of as hazardous waste in sealed, marked bags to prevent further contamination.