Environment, health and safety

Safety on an operating site is a legal obligation with clocks attached, not a value statement. The difference matters at the moment something happens, because the obligations start running whether or not anyone has decided what to do.

Controls in order of effectiveness

The hierarchy is not advice about preference. It is a ranking by how much the control depends on a person behaving correctly under pressure, and everything below the third rung does.

1. Elimination — the hazard is not there. The task is designed out, or done elsewhere.
2. Substitution — a less hazardous material, process or energy source.
3. Engineering — guards, interlocks, ventilation, barriers. The hazard remains; reaching it does not depend on judgment.
4. Administrative — procedure, training, signage, permits, rotation.
5. Personal protective equipment — the last line, worn by the person the hazard is nearest to.