In CBRN risk management, how do hazard, risk, and exposure relate?

• A. All three are unrelated concepts.
• B. Exposure is contact with the hazard.
• C. Risk is the likelihood and consequence of harm; hazard is a potential source of harm; exposure is contact with the hazard; risk is a function of hazard, exposure, and vulnerability.
• D. Hazard is the likelihood of harm.

Answer: (C)

In CBRN risk management, risk is the likelihood and consequence of harm, and it arises from how dangerous a source is, how much contact people have with it, and how susceptible they are. A hazard is a potential source of harm—like a toxic chemical, a radiological plume, or a corrosive agent. Exposure is the actual contact with that hazard—being in the area, inhaling fumes, or receiving a dose. Risk isn’t just about the hazard or the exposure alone; it’s a function of hazard, exposure, and vulnerability. When a potent hazard is present but exposure is minimized by barriers, protective equipment, or quick evacuation, and the population is less vulnerable, the overall risk drops. For example, a highly potent gas in a confined space poses high hazard, but strong controls and limited exposure can keep risk low. The other choices omit these essential relationships: hazard isn’t the likelihood by itself, exposure isn’t the full picture of risk, and saying all three are unrelated ignores how they interact to produce risk.