Asbestos is found in form of silicate fibers that are very light in weight and can easily travel by air. These fibers or dust particles of asbestos are easily inhaled or swallowed and cause various diseases including asbestosis, a chronic lung disease; mesothelioma, cancer of the lining of lungs, chest and stomach and other deadly diseases.

Here are some helpful resources on asbestos:

The affects of asbestosis take years to be come apparant and then affect the lungs. As it is sealed i doubt that you are actually being exposed to it.