Which of the following indicates that you should remain cautious even after using a Type B extinguisher?

Using a Type B extinguisher, which is designed for flammable liquids, is a critical step in fire control; however, it is essential to remain cautious even after the fire appears to be extinguished. The presence of a strong, persistent odor after using a Type B extinguisher is a key indicator that the fire may not be completely out. Certain materials can smolder or continue to emit fumes long after visible flames have disappeared. This odor may signal that flammable liquids have not fully combusted or that there may still be hidden hot spots that could reignite.

Conversely, while a completely dark area may seem concerning, it does not inherently indicate a fire risk. Similarly, if no flames are visible, it may suggest that the fire is under control, but it doesn't guarantee that it can't reignite. Lastly, a lack of noise in the vicinity doesn't provide valid information regarding the potential presence of fire or any ongoing risks. Thus, always being alert to the characteristics of the environment, especially strong smells indicating potential hazards, is crucial for safety following the initial firefighting efforts.