The scent of gas is usually the most common sign of its presence, but pure natural gas is actually odorless. The familiar, rotten-egg aroma that you sense when the pilot light of your furnace blows out is produced by sulfur-based compounds called thiols that were added to natural gas to aid in its detection. This began after the 1937 New London School explosion in New London, Texas, considered the deadliest school disaster in American history. The explosion killed 295 people, many of them children. Ever since then, we’ve doctored natural gas to try to keep better tabs on it.
But millennia before that, it was precisely the elusiveness of natural gas that made it so intriguing. Lightning strikes that ignited natural gas seeping from the ground inspired awe in the ancient world, with the flames serving as objects of religions devotion in cultures ranging from the Zoroastrians to the Ancient Greeks. Near Kirkuk in Iraq, one such fire, known as Baba Gurgur, still burns; some believe this is the “fiery furnace” referenced in the Old Testament, when the Babylonian King Nebuchadnezzar punished three Jews who refused to worship the flames by throwing them in. The Temple of Apollo at Delphi, one of the most important shrines in ancient Greece, was built on top of a gas leak, and scientists now believe that the famed divinations of the temple priestess were a product of the vapors that emanated from underground.
It wasn’t until the late 18th century that the first commercialized natural gas appeared, in Britain. Gas lamps, which relied on natural gas produced from coal, illuminated homes and streets, fundamentally shaping modern notions of urban “nightlife.” Today, in an era of light pollution, it’s difficult to imagine just how powerful this change must have been. Although gas was not the first form of artificial lighting, it produced 12 times as much light as a candle or oil lamp, as Jon Henley reported for The Guardian in a story about the advent of artificial light, and was 75 percent cheaper. By the early 19th century, several other countries began to follow Britain’s lead, including France and Germany. In 1816, Baltimore became the first city in the United States to adopt gas lighting. “Darkness, our primordial dread,” Henley wrote, “was about to lose its dominion.”
But the adoption of natural gas also caused a great deal of anxiety. The Catholic Church strongly opposed it, arguing that God had made a clear delineation between night and day. Some speculated that lengthening the day could also have negative health impacts on the general populace. Others worried about the gas lamps themselves, since many were shoddily constructed: The first gas pipes were made of wood, with mud sometimes used as a sealant. Fires and explosions were commonplace.
Since that time, however, we’ve developed a variety of tools and sensors to properly identify gas leaks. In my work, I relied primarily on a Flame Ionization Detector (or “F.I.,” for short) that shared an uncanny likeness with the Ghostbusters’ ghost trap. As I walked the gas lines (laid out in maps with routes for me to follow), I waved a long wand, attached to the F.I. unit, at the ground. Inside of the machine a small flame burned hydrogen gas, which flared up and set off a whining alarm any time a threshold amount of natural gas entered the chamber. When I suspected that a residential gas meter was leaking, I brushed it with a solution of dish soap and water. Heavy leaks produced large, billowy bubbles that helped me to pinpoint the source of the escaping gas. Smaller leaks emitted tiny soapsuds.