Massive methane leaks, known as super-emitter events, have been taking place at oil and gas fields all over the world, from the United States to Turkmenistan. The releases, most of which can be traced to equipment failures, can last for weeks. One outside of a storage facility in Los Angeles in 2015 hemorrhaged almost 100,000 tonnes of methane — a potent greenhouse gas — into the atmosphere over the course of four months.