Any fluid, either combustible or noncombustible, which is produced in a natural state from the earth and which maintains a gaseous or rarefied state at ordinary temperature and pressure conditions. In the oil and gas industries, it means natural gas. Twenty-three states define gas as all natural gas, including casinghead gas, and all hydrocarbons not defined as oil. Generally, the remaining states describe the definition of a gas well, but do not specifically define natural gas.