Propane is produced from both natural gas processing and crude oil refining. It is nontoxic, colorless and virtually odorless. As with natural gas, an identifying odor is added so the gas can be readily detected.
Propane has a narrow range of flammability when compared with other petroleum products.
If the mixture contains less than 2.2 percent gas, it is too lean to burn. If it contains more than 9.6 percent, it is too rich to burn. Propane won't ignite when combined with air unless the source of ignition reaches at least 940 degrees Fahrenheit. In contrast, gasoline will ignite when the source of ignition reaches only 430 to 500 degrees Fahrenheit. The odds of a person dying from a direct result of a propane transportation or storage accident involving loss of cargo are about the same as those of getting struck by an airplane falling from the sky.