During my senior year of high school, I quit my job at the local minor-league baseball stadium and got a new one checking gas lines in the Chicago suburbs. I didn’t realize at the time I signed on that I would spend four summers and one winter of my life investigating gas leaks, nor that it would be so revelatory. My first lesson on the job: Gas is leaking everywhere.

The United States Environmental Protection Agency reports that natural gas and petroleum systems are the largest anthropogenic source of methane in the U.S., and the second-largest globally. Methane is the primary constituent of natural gas; it’s about 30 times more potent than carbon dioxide, making it a colossal greenhouse gas. And every day the vast networks of underground gas lines in the country leak it into the atmosphere.

I had been tasked with finding the leaks in the system. It didn’t take me long to notice that the leaks were particularly abundant in older suburbs, where aged copper lines hadn’t yet been replaced by aluminum or plastic. In the towns of Cicero and Berwyn, I could find up to three leaks in a given residential yard, and as many as a few dozen on a single densely populated block. In some neighborhoods the smell of gas was so pervasive that it hung steadily in the air, as if it belonged there.

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.

I was required to document all the leaks that I found, but the gas company only immediately fixed those leaks that were within five feet of an enclosure. Finding such “class 1s,” as they are known in industry parlance, initially gave me a little rush of excitement, followed by some vaguely defined sense of occupational satisfaction. “Hell, I may have even saved a life today,” I’d think to myself in early moments of naïve self-congratulation.

But over time, I learned a surprising truth: The bulk of the gas leaks identified are left leaking. Those between five to 15 feet from a house or structure would receive a check-up after six months. Leaks more than 15 feet from a building were noted but required no special attention. Many of the leaks persisted for years and even decades. My boss, a man of great professional dedication, was so familiar with the leaks on his turf that he kept their dates and locations locked in his memory. He could point to a circular burn in a nondescript suburban lawn as we drove past and say, “There’s another. I found that one 10 years ago.”

Given that much of suburban America is carpeted in turf grass, one of the most common signs of a gas leak is the circular burn patch that it produces in the lawn. The intersecting point of the “T,” where the household service line meets the main gas pipeline, is a common place for such burns to occur. Many homeowners try laying fertilizer and lawn food over the patch of dead grass, or replacing it with sod or new seed, but none of these measures can overcome the blemishes left by a natural-gas leak, the relentless foe in Americans’ obsessive quest for the perfect lawn.

Yet aside from the cosmetic defects they create, the majority of gas leaks pose little threat. Most people tend to become alarmed when they learn that there’s a gas leak on their property, but really, a gas leak in the middle of the lawn is no serious danger. Natural gas is only explosive when mixed in the air at a concentration between 5 and 15 percent. When it leaks into an enclosed space, like a basement, it can be a serious problem. And leaks that find their way into sewer lines also present potential hazards. But the likelihood of dying from a natural-gas explosion is slim.

On average, the United States loses 17 people a year to leaks and explosions involving natural-gas pipelines. Statistically speaking, you are more likely to die from autoerotic asphyxiation (which causes around 600 deaths each year) or falling out of bed (around 450 people) than gas explosions. Even deaths by lightning strike are more common, with 26 fatalities in 2014. Aside from their contribution to climate change, most natural-gas leaks pose little threat. And, for that reason, the gas company generally lets them be.

No matter how much work we do to police them, there will be gas leaks for as long as there are gas lines. Even if the number of people surveying and repairing gas lines drastically increased in the next year, old leaks would still persist and new ones would still appear. Much of our infrastructure is designed to channel substances that we can’t fully control: Water eats away at pipes, sewage clogs and bursts them, and gas inevitably escapes. This is what Andrew Pickering, a sociologist of science, described as the “dance of agency” between humans and the broader material world: To assume that we can fully control this world, he argued, is at best naïve, and at worst dangerous.

The people who check leaks for a living are not particularly easy to control, either. To be alone for eight hours a day in search of gas leaks is not easy. Some of my co-workers snoozed in their cars during the early morning hours of a shift; I was guilty of the occasional catnap on a rainy day during regular work hours. I even left early on more occasions than I would like to admit, leaving the route unfinished for the day. On my worst days, I stopped caring whether I was even covering the lines at all. It wasn’t just the monotony of the job that eventually got to me. It was the futility: the knowledge that the vast majority of the leaks would never be repaired and would continue leaking indefinitely.

It didn’t take long for the untamable nature of gas leaks to strip me of the false impression that doing my job meant chipping away at a problem, that each day of work meant we were that much closer to solving it. Tracking leaks was a reminder that our creations—from high-rise condominiums to topiary gardens to gas pipelines—are not just ours: They belong to a much broader world that is often well beyond our control, even when we try to pretend otherwise.