First, let's have a look at what asbestos actually is. Asbestos occurs in nature. It is a fibrous material. Since 150 it has been used in broad variety of applications. It is flexible, yet, very sturdy and durable. Furthermore, it is know for its outstanding thermal qualities and was therefore used for all kinds of insulation purposes. However, it is hazardous and contact to the material can potentially result in death later on. Asbestos has been commercially used in three variations. Amosite (brown color) Crocidolite (bluish) Chrysotile (white color). The brown and blue asbestos poses a greater degree of danger to humans that the white one. A conclusive distinction between the three types can only be made in a specialized laboratory.

Please visit the HSE website (source of the asbestos pictures below):

If asbestos fibers are being ingested or inhaled, they can attach to the tissue of your lungs. This may result in severe diseases such as mesothelioma, asbestosis, kidney cancer and lung cancer, especially if a person has been exposed to the material frequently over a longer stretch of time. Experts say that that if asbestos remains undisturbed, which typically means undamaged, there is no harm coming from the material. Thus, if for instance the asbestos floor tile in your house is good condition, it is usually safer to leave them the way they are and just install another lawyer of flooring on top of it. It might also be a good idea to have asbestos testing done by a certified asbestos consulting service. Contrary to the perception of many people, white asbestos is not safe. Chrysotile is a category 1 human carcinogen. Exposure to any kind of asbestos can result in serious health conditions, such as asbestosis (scarring of lung tissue that is irreversible), lung cancer (especially smokers are at a higher risk) and mesothelioma (which is a cancer that affects the lung lining or organs in the abdomen). It's important to note that all of the mentioned diseases are incurable and further to that, mesothelioma and lung cancer are fatal conditions.