A laboratory at a depth of 1000 m.w.e is shielded from cosmic rays equivalently to a lab 1,000 m (3,300 ft) below the surface of a body of water.
Because laboratories at the same depth (in meters) can have greatly varied levels of cosmic ray penetration, the m.w.e.
provides a convenient and consistent way of comparing cosmic ray levels in different underground locations.
[2] For example, the Waste Isolation Pilot Plant, located 660 m (2,170 ft) deep in a salt formation, achieves 1585 m.w.e.
Soudan Mine, at 713 m (2,339 ft) depth is only 8% deeper, but because it is in denser iron-rich rock it achieves 2100 m.w.e.
In addition to m.w.e., underground laboratory depth can also be measured in meters of standard rock.
Underground laboratories exist at depths ranging from just below ground level to approximately 6000 m.w.e.