All practicable steps, including support or battering, prevent collapse, dislodged material and burial; people, equipment and materials are prevented from falling in and edges from overloading; supported excavations are inspected by a competent person at the start of each shift and after events affecting stability or falls of material, and work stops until defects are remedied.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.