Asbestos is a naturally occurring mineral found in certain rock formations, mined from open pit mines. Most of the asbestos used in the United States today comes from Canada. Three kinds of asbestos are most commonly found in the United States: chrysotile, "white asbestos"; amosite, "brown asbestos"; and crocidolite, "blue asbestos". Asbestos was called the "miracle fiber: because it could be used in so many different products. Asbestos was not expensive, easy to work with, and it was abundant. The fibers were wonderful because they didn't burn and didn't conduct heat and electricity. The fibers were durable, strong, flexible, and resistant to wear. More than 3000 different products were made using asbestos. Some of these included pipe insulation, sprayed-on fireproofing, floor tiles, ceiling tiles, brake pads, clutch facings, plasters, mastics, adhesives, gaskets, packing materials for valves, asbestos gloves, siding shingles, roofing materials, firemen's clothing, and thousands more products.
In the 1960's evidence began to emerge showing that certain diseases were prevalent among asbestos workers. These were the workers who worked in the mills, manufacturing facilities, shipyards, etc. These people had, for the most part, several years of heavy exposures to the airborne fibers. In other words, they were at high risk of developing an asbestos-related disease. These diseases are asbestosis, lung cancer, mesothelioma, and digestive system cancers. Fibers may be inhaled (breathed in) or ingested. By far the more important source of exposure is inhalation of the fibers. The fibers are very small and can remain in the air for several hours. The ones that can be inhaled deep into the lung are too small to see and have no odor. Asbestosis (not a cancer) is a chronic lung condition where the lungs become scarred and thickened. Breathing becomes very difficult and the disease may get worse even if the person stops working with asbestos. Smoking greatly increases the risk of developing lung cancer. Mesothelioma is a very rare cancer of the lining of the lung or abdominal cavities and is always fatal in 6-18 months after diagnosis. None of the asbestos-related diseases have early warning symptoms and are usually diagnosed several years after the disease begins to develop.