What distinguishes a hazard from risk in risk assessment?

• A. A hazard is a source of potential harm; risk is the likelihood and consequence of that harm.
• B. Risk is a source of potential harm; hazard is the likelihood and consequence of that harm.
• C. Hazard is a measurement of probability; risk is the severity of injury.
• D. Hazard and risk are identical terms in risk assessment.

Answer: (A)

Hazard vs risk: a hazard is a source of potential harm—things or situations that could cause injury or damage, such as gas accumulations, loose rock, or energized equipment. Risk is about how likely that harm could occur and how severe the outcome would be if it did. In risk assessment you identify hazards and then estimate risk by considering the probability of exposure to the hazard and the consequences if exposure leads to harm. This is why the statement that a hazard is a source of potential harm and risk is the likelihood and consequence of that harm is the best description. Other ideas—likening risk to a source of harm, or treating hazard as a probability measure, or saying they’re identical—don’t fit because risk depends on both likelihood and outcome, given exposure, while hazard is simply the potential for harm.