How Asbestos Fibers Cause Disease
Breathing in asbestos fibers can cause pleural plaques, lung cancer, mesothelioma, and asbestosis. Although the exact mechanism isn’t completely understood, doctors and researchers believe that the reason people develop these diseases from breathing in asbestos has to do with the size and consistency of the different asbestos fibers.
Normally, when you breathe in irritating substances, your body produces mucus. The mucus surrounds the substance, and when you cough, the substance is expelled. Fibers are also removed by the immune system through a process called phagocytosis.
Some asbestos fibers are expelled the same way as other foreign substances. But asbestos fibers sometimes get past the body’s defenses and remain inside your body. It is believed that these cause irritation, which eventually leads to disease.
When fibers get inside the lung and cause scarring, this can lead to asbestosis and lung cancer. When fibers get into the lining of the lung, called the pleura, they irritate and injure cells. This triggers the body to surround them with calcium, thereby causing pleural plaques – or the irritation may lead to mesothelioma. Mesothelioma of the abdominal lining may be caused by swallowing asbestos fibers.
Types of asbestos fibers
There are two types of asbestos fibers: amphiboles and serpentines. Amphiboles are long needle-like fibers. They don’t break down easily and are believed to remain in the tissues in your body for years. Serpentine fibers have a corkscrew shape. They break down more easily, but are still very strong.
- Crocidolite, an amphibole, is believed to be the most carcinogenic (cancer-causing) type of asbestos and is strongly associated with mesothelioma.
- Chrysotile, which makes up most of the asbestos used in the US, is a serpentine fiber. When contaminated with tremolite (an amphibole), it becomes the most carcinogenic and most likely to cause malignant mesothelioma.
- Other amphiboles are amosite, anthophyllite and actinolite.
- Vermiculite, a mineral mined in Libby, Montana, and used in insulation and mixed into garden soil to make it light, has also been associated with mesothelioma. The incidence of mesothelioma found in those living near the mine has risen sharply.
Asbestos, a naturally occurring group of minerals, has been used in industry since the late 1800s. Even though the risks were known several decades earlier, asbestos continued to be used in many industries through the 1970s. Because these diseases usually take a long time to manifest symptoms, people exposed decades ago are often just starting to become ill now. Most victims are in the 50- to 70-year-old range.
The highest risk of exposure to asbestos has been seen in people doing insulation work, working in asbestos factories and mining, the heating trades, shipbuilding, brake repair, and construction. World War II saw hundreds of thousands of military and civilian workers exposed to asbestos, particularly in shipyards and factories.
Asbestos use is far less today, but it’s still being used in the manufacture of some fire safety products. It’s also a threat to people doing home renovations on buildings built before the late 1970s.
A detailed history of your exposure to asbestos is an important component of helping your doctor diagnose asbestos-related diseases, particularly mesothelioma.