What expansion ratio is indicative of propane gas's potential risk in fire scenarios?

The correct choice reflecting the expansion ratio indicative of propane gas's potential risk in fire scenarios is 270 to 1. This means that one volume of propane can expand to 270 volumes of gas when it vaporizes. This significant expansion ratio highlights how a relatively small quantity of propane can produce a large amount of gas, which can lead to an increased risk of fire or explosion in confined spaces or areas with poor ventilation.

Understanding this principle is vital for emergency responders, as it underscores the need for careful handling and monitoring of propane in situations where it may accumulate. The large expansion ratio contributes to the potential for rapid fire spread and intense heat release, making propane a substance requiring specific safety precautions during transport, storage, and usage, particularly in fire scenarios.