A key factor in the risk of developing an asbestos-related disease is the total number of fibres breathed in. Working on or near damaged asbestos-containing materials or breathing in high levels of toxic asbestos fibres, which may be many hundreds of times that of environmental levels could increase your chances of getting an asbestos-related disease.
When asbestos fibres are inhaled they can cause serious diseases which are responsible for around 4000 deaths a year in the UK alone. There are four main diseases caused by asbestos: mesothelioma (which is always fatal), lung cancer (almost always fatal), asbestosis (not always fatal, but it can be very debilitating) and diffuse pleural thickening (not fatal).
Remember, these diseases will not affect you immediately but later on in life, so there is a need for you to protect yourself now in order to prevent you and others from contracting an asbestos-related disease in the future. It is also important to remember that people who smoke and are also exposed to asbestos fibres are at a much greater risk of developing lung cancer.