Propane gas is _____ than air, which can pose hazardous conditions when a heater is installed in a pit.

The correct choice states that propane gas is heavier than air. This characteristic is crucial when considering the placement of heaters using propane in enclosed spaces like pits.

When propane escapes into the environment, it tends to settle at lower levels due to its higher density compared to air. This behavior can create potentially hazardous conditions, as the propane can accumulate in low-lying areas and create the risk of fire or explosion if an ignition source is present.

Understanding the properties of propane gas, particularly its density relative to air, helps in making informed decisions about safety measures and equipment installations, including ensuring proper ventilation in areas where propane heaters are utilized. Proper venting and safety protocols can mitigate the risks associated with propane's tendency to accumulate in pits.