Exact location and access routes will be especially helpful. Many of the dangers posed by these sites are not readily seen, or cannot be seen at all. The darkness and debris in old mines make identification of the hazards difficult. At the surface, openings can be hidden by vegetation or covered by rotting boards or timbers. Inside old mines, shafts can be camouflaged by debris, or hidden by darkness in the mine.
Explosives become unstable with age, and can be detonated by the vibration of footsteps.
Abandoned chemicals such as cyanide, arsenic, mercury and other deadly toxins may be present in leaking and deteriorating containers. Oxygen deficient air may cause suffocation. People have died within a few feet of the mine openings. These are the excavated vertical cliffs in surface pits and quarries. They can be unstable and prone to collapse.