Which of the following is NOT a form of Engulfing Event deposit?

• A. Cloud
• B. Plume
• C. Cone
• D. Bubble

Answer: (D)

Engulfing Event deposit forms describe how a hazardous release disperses in the air and what the resulting environmental pattern looks like around the source. In typical scenarios, you’ll see shapes like a cloud, which is the visible hazy mix of vapor with air; a plume, which extends downwind as the vapor travels with the wind; and a cone, which forms near the source due to the way the gas spreads and interacts with the surroundings.

A bubble, however, is different. It exists when gas is trapped inside a liquid or within a closed system, forming a pocket or bubble in a liquid rather than creating a spreading pattern in the air. That localized gas pocket isn’t an example of the airborne deposition patterns associated with an engulfing air release, so it’s not considered a form of Engulfing Event deposit.