Gaze into North Dakota’s sky some night, and you might see flickering as flames light up the sky. That’s the sight of oil companies wasting staggering amounts of natural gas, the New York Times reports. The gas bubbles up alongside oil in the state’s Bakken shale field, and because oil is more lucrative, companies simply burn off the gas—wasting more than 100 million cubic feet of it a day, enough to heat 500,000 homes.
The fires throw at least two million tons of carbon dioxide into the atmosphere annually, about as much as 384,000 cars, the Times notes. North Dakota isn’t alone—the practice is common overseas—but it's the US’ top culprit. “North Dakota is not as bad as Kazakhstan,” says one energy expert, “but this is not what you would expect a civilized, efficient society to do.” Oil companies counter that capturing the gas doesn't make economic sense. “I’ll tell you why people flare,” says the owner of a gas-processing plant: “It’s cheap.”