What is Mercaptan?
Natural gas is one of the safest, most efficient and most reliable forms of energy available. But, like any energy source, natural gas must be used properly.
Natural gas is colorless and odorless. We add a harmless, non-toxic chemical called Mercaptan to natural gas, so that it's easier to detect a gas leak before it can create a hazardous situation. The chemical has an odor similar to rotten eggs. If you aren't familiar with tje odor, call Columbia Gas DirectLink at 1-800-344-4077 and ask for a "scratch-n-sniff" card that provides you with a sample of the odor.
Mercaptan contains sulfur. That's what gives it an odor. The kind we use blends well with natural gas and, in a gaseous state, has much of the same properties as natural gas, so it will also rise and dissipate with natural gas.
In a concentrated form, the odor of Mercaptan is almost unbearable. And it takes only a few parts per million of mercaptan to give natural gas a smell. That is precisely why we add it to natural gas. Without mercaptan, it would be difficult to determine that unlit natural gas was coming from your stove after you left the valve turned on. Leaks from furnaces and hot water heaters would be nearly impossible to detect without expensive equipment. So mercaptan's odor is a very valuable safety feature.
There are other uses for mercaptan in industry, including jet fuel, pharmaceuticals and livestock feed additives. It is used in many chemical plants. Mercaptan is less corrosive and less toxic than similar sulfur compounds found naturally in rotten eggs, onions, garlic, skunks, and, of course, bad breath. In other words, forms of mercaptan can be found in things that smell.