Toxicity and hazard are synonyms. Which statement is true?

• A. True
• B. False
• C. Sometimes
• D. Not related

Answer: (B)

Toxicity and hazard are not the same thing. Toxicity is the inherent ability of a chemical to cause adverse health effects at a certain dose and through a specific route of exposure. Hazard, however, is the potential for harm under real-world conditions, which depends on both how toxic the substance is and how likely it is that people will be exposed to it, by what route, and for how long.

That means a substance can be very toxic but pose little hazard if exposure is unlikely or tightly controlled. Conversely, a substance with relatively low inherent toxicity can still present a significant hazard if exposure is frequent or unavoidable, or if it has properties that facilitate exposure (like high volatility or ease of inhalation).