Sandblasting is a general term used to describe the act of propelling very fine bits of material at high-velocity to clean or etch a surface.  Sand used to be the most commonly used material, but since the lung disease silicosis is caused by extended inhalation of the dust created by sand, other materials are now used in its place. Any small, relatively uniform particles will work, such as copper slag and calcium silicate.  Due to the dangers of sandblasters inhaling dust during the process, sandblasting is carefully controlled using an alternate air supply, protective wear, and proper ventilation.