A legal concept under OHS law requiring employers to do what a reasonable person would do in the same situation to protect health and safety. This involves considering:
1. The likelihood of a hazard or risk eventuating
2. The degree of harm that would result if it did occur
3. What the person concerned knows, or ought reasonably to know, about the hazard
4. The availability and suitability of ways to eliminate or reduce the risk
5. The cost of removing or mitigating the risk
