When a system for hazardous chemicals will no longer be used or will be disposed of, the PCBU ensures so far as reasonably practicable that it is free of the chemicals, or correctly labels it if removal is not reasonably practicable; for underground systems ensures so far as reasonably practicable that the system is removed or, if not, left without risks; and notifies the regulator as soon as practicable when an underground, partly underground or fully mounded tank that stored flammable gases or liquids is abandoned (unused for 2 years or not intended to be used again).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.