Natural gas is called “natural” because when this type of gas was first discovered, it could be used directly from the ground in its natural state, without any processing. Today, gas utilities process natural gas by removing water, sand, and other compounds so that when the gas is delivered to your home, it will burn as cleanly and efficiently as possible. And in its natural state gas has no odor. That’s why gas utilities add a harmless but stinky chemical called mercaptan; the odor helps people smell a leak that otherwise, in the gas’s natural state, doesn’t smell.