Propane is a reliable energy source that is used every day by millions of people worldwide. Customers enjoy the value propane gives them for their energy dollars, and appreciate its environmentally friendly, clean-burning properties. Propane has many residential, industrial/commercial, and agricultural uses, but much has to happen before it makes it to that point. Propane is a member of a family of chemical compounds called hydrocarbons, and is found in both crude oil and natural gas. When crude oil is drawn from a well, it is refined into various petroleum products. Propane is a derivative of this process. When natural gas is drawn out of the earth, it is a mixture of several hydrocarbon gases. Approximately 5 percent of this mixture is propane. Methane, ethane, butane, pentane, and other heavier hydrocarbons also comprise the mixture. These gases are separated through a process called fractionation. Stored as a liquid, propane is easily transportable and can provide energy in places natural gas cannot. After it is gathered through natural gas processing and crude oil refining, propane is stored in underground salt and rock caverns until it is ready to be shipped to terminals throughout the United States via some 70,000 miles of pipeline. Propane also is popular as an alternative motor fuel. In fact, more vehicles run on propane nationally than all other leading alternative motor fuels combined. Propane is preferred as a motor fuel over diesel and gasoline because it is clean-burning and non-toxic. Before propane reaches the consumer, an odorant called ethyl mercaptan is added as a safety measure to help ensure the timely detection of propane vapors in the event of a leak. Econogas Customers are urged to familiarize themselves with this odor, which resembles sulfur or rotten eggs.