Australia Model Code of Practice: Managing the Risks of Plant in the Workplace 4.3: 4.3 Fit emergency stops that are prominent, red, reachable and not defeated by circuit failure (r 211)

Where plant has an emergency stop control, the person with management or control must ensure it is prominent, clearly and durably marked and immediately accessible to each operator, that any handle, bar or push button is red, and that the stop cannot be adversely affected by electrical or electronic circuit malfunction. Where plant is operated or attended by more than one person and has multiple emergency stops, they must be stop and lock-off type so the plant cannot restart after use unless each activated stop is reset. An emergency stop should be a back-up to other controls, not the only control. Once engaged it should remain so until deliberately disengaged, disengaging should not restart the plant, only allow the normal start sequence, and stop controls on plant that works with other equipment should stop all related equipment where continued operation could be dangerous.