Which characteristic of propane vapor can be hazardous in confined spaces?

Propane vapor is hazardous in confined spaces primarily because it can displace oxygen. In enclosed environments where propane accumulates, the concentration of propane can reduce the amount of available oxygen in the air. This can pose serious risks, as a lower oxygen level can lead to asphyxiation or unconsciousness.

While other characteristics of propane, such as it being lighter than air, or having the potential to explode, are important in assessing safety, the specific attribute of oxygen displacement is particularly concerning in confined areas. If the oxygen concentration falls below safe levels, it can create immediate health risks for anyone present. Thus, understanding this characteristic is critical for ensuring safety in environments where propane is stored or used.