Depending on how and where asbestos was applied, it might not pose any risk to most users of the building. If the fibers cannot become dislodged, they cannot be inhaled, and thus the asbestos poses no risk. However, some methods of applying asbestos, particularly flocking, allow asbestos fibers to gradually drop off into the air. Asbestos poses hazards to maintenance personnel who have to drill holes in walls for installation of cables or pipes. Even if the workers are protected, such maintenance operation may release fibers into the air, which may be inhaled by others. Interventions in areas where asbestos is present often have to follow stringent procedures.