The presence of asbestos itself is not necessarily a risk, it has been used extensively in the construction of blocks of flats and is often found in pipe lining and lagging and in the roofs of buildings, insulation etc.
The most dangerous thing about asbestos is when it is disturbed and the tiny fibres consisting of fibrous hydrated magnesium silicate particles become loose and airborne, and if inhaled into the lungs this type of exposure to asbestos can be a serious threat to health.
Long term exposure to asbestos leads to shortness of breath, caused by fibrosis of the lung known as asbestosis, and several other health problems including the increased risk of developing cancers of the lung, ovary and larynx as well as mesothelioma (cancer of the lining of the lung). These cancers don’t often develop until decades after the exposure to asbestos occurred.