You cannot tell when you are breathing asbestos. It has no warning properties to let you know it is in the air. It won't make you cough or sneeze, it doesn't make your skin or throat itch. Its fibers are so small that you cannot see it, but you do breathe it and swallow it.
Everyone is exposed to asbestos at some time during their life. Low levels of asbestos are present in the air, water, and soil. However, most people do not become ill from their exposure. People who become ill from asbestos are usually those who are exposed to it on a regular basis, most often in a job where they work directly with the material or through substantial environmental contact.
Information on the health effects of asbestos in humans comes mostly from studies of people who were exposed in the past to high levels of asbestos in the workplace. These asbestos workers were found to have increased chances of getting two types of cancer: cancer of the lung tissue itself, and mesothelioma, a cancer of the thin membrane that surrounds the lung and other internal organs. Both lung cancer and mesothelioma are usually fatal. The amount of time between exposure to asbestos and the first signs of disease can be as much as 30 years. It is known that smokers exposed to asbestos have a much greater chance of developing lung cancer than just from smoking alone.
Besides causing cancer, breathing asbestos can also cause a slow accumulation of scar-like tissue in the lungs and in the membrane which surrounds the lungs. This scar-like tissue does not expand and contract like normal lung tissue, and so breathing becomes difficult. Blood flow to the lung may also be decreased, and this causes the heart to enlarge. When the injury is mostly in the lung itself, the disease is called asbestosis. This is a serious disease, and can eventually lead to disability or death in people exposed to high levels of asbestos.
How small is an asbestos fiber?
One strand of human hair is approximately 1200 times thicker than an asbestos fiber.