A persistent or nonvolatile chemical agent can:

• A. Evaporate quickly
• B. Be washed off easily with water
• C. Break down in sunlight
• D. Remain on a surface for more than 24 hours

Answer: (D)

Persistence is about how long a chemical agent stays on surfaces and remains hazardous. A nonvolatile agent has low vapor pressure, so it doesn’t evaporate quickly. Because it resists rapid removal or breakdown, it can stay on a surface for extended periods, often longer than 24 hours, depending on surface material and environmental conditions. The other statements describe properties that would reduce persistence: evaporation would remove it quickly, washing off with water indicates it isn’t strongly bound, and breaking down in sunlight would shorten its presence. Recognizing this helps guide decontamination and protective measures for responders.