Workers loading a compactor containing low-level nuclear waste at the Oak Ridge National Laboratory (ORNL), Tennessee. Low-level nuclear waste consists of contaminated glass, metal, fabrics and other equipment and was previously stored in cans buried in unlined trenches. Following new legislation, ORNL now categorises all waste before it is sealed in these steel cans inside concrete vaults. The vaults are then either buried in silos underground or stored on a concrete Tumulus" pad above ground."