What is added to propane to give it a distinct odor?

Propane is an odorless gas in its natural state, which can pose significant safety risks if there is a leak, as individuals may not be aware of it. To mitigate this risk, a distinct odor is added to propane to help in the detection of leaks. Ethyl mercaptan is the compound used for this purpose. It has a strong, sulfur-like smell that is easily recognizable and serves as an important safety feature for anyone who may be working with or around propane. This ensures quick detection of potential leaks, allowing for timely responses to prevent accidents or hazardous situations.

The other options listed do not serve this particular function with propane. Methyl formate, terthiol, and isoamyl acetate are not used for odorizing propane and do not provide the same level of safety in detecting gas leaks.