Steve Conley got the call early on Nov. 5. A natural gas storage well was leaking methane into the air at Aliso Canyon, near a Los Angeles suburb, and no one knew just how bad it was—could he get a read on it? Conley, an atmospheric scientist and a pilot, rushed to a small airport northeast of Sacramento. He’s flown more than 1,500 hours measuring emissions over oil and gas operations in one of his two single-engine Mooneys. Tubes mounted on each Mooney’s right wing suck air into two chemical analyzers stored in the luggage compartment. Soon Conley was soaring south across California’s Central Valley.
The leak had been spewing for about two weeks. Southern California Gas Co., the subsidiary of Sempra Energy that owns the facility at Aliso Canyon, had tried and failed to kill it. The previous night, homeowners from the nearby neighborhood of Porter Ranch had gathered to rail about the rotten-egg smell taking over their community. Tim O’Connor, a lawyer at the Environmental Defense Fund (EDF), attended the meeting, and feared the leak could be big enough to threaten not only the local community but also the earth’s climate.
As the Mooney flew closer, O’Connor, who’d hired Conley, phoned Aliso’s on-site incident commander with a heads-up about the flight. The SoCalGas staffer refused to approve the flyby, O’Connor says. “They said that the events on the hill were too dangerous and any additional distraction at that time could create an unsafe condition.” This didn’t make immediate sense to O’Connor. Conley wanted to fly a mile downwind of the leak to measure its plume, not directly overhead, and the whole area bordered the flight path of a nearby airport—planes in the distance were a common sight. Nevertheless, O’Connor gave SoCalGas the benefit of the doubt. Conley was a few miles out when O’Connor texted, instructing him to turn around. SoCalGas stands by its reasoning.
Two days later, Conley again flew to Aliso, this time on the state’s dime. Conley started flying back and forth downwind of the site, taking measurements and gaining elevation with each pass. As data populated his screen, he recalls thinking, “What the hell is that?” The levels appeared to be at least 15 times greater than he’d ever observed. Equipment malfunction? The second analyzer showed the same readout. “This isn’t an error,” he concluded. After 17 laps, he reached the top of the plume and headed home.
Based on Conley’s readings, the state would estimate that in less than a month, Aliso released more than 68 million pounds of methane. Since then, it’s leaked 132 million pounds more, the state says, based on Conley’s subsequent flights. That makes Aliso potentially the largest-ever single release of methane into the atmosphere—at least, the largest ever recorded. Even as the U.S. pledges to reduce greenhouse gas emissions, methane leaks large and small are going unaddressed.
Roughly 95 percent of the natural gas that fuels stove-tops and power plants is methane. Scientists take pains to observe it because while it doesn’t last in the atmosphere as long as carbon dioxide, it’s a far more potent greenhouse gas while it’s there. Methane burns quite cleanly compared with coal, but when it escapes into the air, it has 84 times the global warming impact as carbon dioxide over 20 years.
When methane leaks, it’s not obvious like an oil spill. Methane’s invisible and, for most of its supply chain, has no odor. That helps explain why there’s been such a gap in public awareness of what a growing body of research has found: There are pervasive, daily methane leaks across the country’s energy infrastructure that far outstrip federal estimates. And the bulk of releases come from “super emitters,” which range from persistently malfunctioning valves to one-time events.
Aliso’s drawn attention to methane like no other emission. It’s releasing in an urban area, the one part of the supply chain where methane’s mixed with sulfurous chemicals so leaks can be detected by smell. And researchers and activists have made the leak’s massive plume a must-see. On Dec. 20, EDF released the first infrared aerial footage of the Aliso leak. The video, taken by O’Connor and a colleague in a rented Cessna, shows a haunting black cloud streaming endlessly from the hillside. Viewed more than 1.3 million times on YouTube, the viral image shows the threat that has led thousands of Angelenos to leave their homes. It also exposes a major challenge to the climate benefits of the country’s shift from coal to gas. SoCalGas has vowed to mitigate the greenhouse impacts from Aliso, though it hasn’t specified how—or how much it will cost.
Before there were 30,000 residents living on pleasant streets like Via Botticelli and Vista Grande Way, Porter Ranch was just the scrubby foothills of the Santa Susana mountains, which run along the northern edge of the San Fernando Valley. In the late 1930s, an oil company owned by J. Paul Getty started drilling for crude among the ridges. Wells there produced for decades before depleting the reserves.
In 1971, SoCalGas bought the Aliso Canyon site and converted it to storage for natural gas. SoCalGas uses the 115 wells there to inject gas into the same underground field that once held oil. It’s the fifth-largest among about 400 such storage facilities nationwide and supplies 11 million customers across the Los Angeles basin. Since developers built subdivisions starting in the late 1980s, the community peacefully, if unknowingly, coexisted with the subterranean lake of gas.
Then, late in the day on Friday, Oct. 23, workers around Well SS-25 noticed the sulfurous smell. At the time, “it was not something that was alarming to us,” says Jimmie Cho, senior vice president for gas operations and systems integrity at SoCalGas. Minor leaks are routine in the industry. The workers went home for the night.
The next day, SoCalGas tried to stop the leak by using a typical technique of forcing a salty fluid down the well to overpower the upward pressure of the escaping gas. Cho says to imagine holding a giant straw between your lips, tilting your head back, and blowing, as liquid is poured into the open end. “You fill the straw up with fluid, and you’re pushing against it, you’ll keep bubbling that liquid,” Cho says. But “at some point, there will be so much liquid, your lungs won’t be able to actually push any more.”
It didn’t work. So the company called in Boots & Coots, a Halliburton subsidiary based in Houston that specializes in wrangling control of leaky wells. SoCalGas also stopped injecting new gas into the facility, which was close to its peak capacity, about 86 billion cubic feet, as the company prepared for winter demand.
Initially, the gas wasn’t spewing directly from the wellhead. Boots & Coots determined it was seeping from the well’s casing about 500 feet below the ground. The gas worked its way up and out into the atmosphere through the soil. “It was almost like gas was coming up through a sponge and making its way through various cracks and natural parts of the geology,” Cho says.
Boots & Coots tried to more forcefully shove brine down SS-25 only to discover an ice plug had formed in the well, complicating access to the leak. Cho says the ice may have resulted from a pressure imbalance during an early kill attempt. Breaking down the ice required long coiled tubing, hauled in from Louisiana on four semi-trucks, that works like a plumber’s snake. In early November, Boots & Coots broke through the ice plug. Then, on Nov. 13—a day, Cho says, that is “etched in our memory”—another kill attempt only made matters worse.
As Boots & Coots again pushed brine down the shaft, the upward pressure of the leak dramatically overwhelmed the downward force of the fluid. Cho says the brine formed a channel through the soil as it came back up to the surface, which created a highway of sorts for the liquid—and later gas—to escape faster. “It went from very diffuse to very focused,” Cho says. “That may have been part of the reason why ... the [leak] rate may have changed,” Cho says cautiously. Conley found that by Nov. 28, emissions were about 16 percent higher than he’d measured a few days before the kill attempt. At its peak, Aliso emitted almost 128,000 pounds of methane an hour, Conley estimates. (Boots & Coots deferred comment to SoCalGas.)
On Nov. 19, after another kill attempt, SoCalGas announced a Plan B that may sound familiar from the 2010 Deepwater Horizon oil spill—digging a relief well to intercept SS-25 at its base, about 8,600 feet below ground. The drilling started on Dec. 4. SoCalGas said around that time it could take months to complete the task.
By the middle of December, reality was setting in at Porter Ranch that the leak wouldn’t be plugged anytime soon. More residents began asking SoCalGas to pay for temporary housing, and the company opened an office in a shopping center, wedged between SoCal Blow Dry Bar and Visionmax Optometry, to field their complaints. Hundreds of people have been showing up each day, and about 4,460 households are living in hotels or other short-term accommodations, at SoCalGas’s expense.
Plaintiffs lawyers, including Robert F. Kennedy Jr., courted panicked residents, saying SoCalGas should pay for what they called unknown health risks and wrecked property values. More than 2,000 people showed up for a December meeting organized by Erin Brockovich and the lawyers she works with.
A month later, on a Friday evening in mid-January, hundreds of Porter Ranch residents packed the pews of Shepherd of the Hills Church. Onstage, 11 state officials sat at long tables, resembling a modern-day Last Supper. Their backdrop was a set of partially constructed stone houses, under way in early preparation for the church’s popular Broadway-style Easter pageant. Dudley Rutherford commanded the attention of the crowd as only a megachurch pastor can. “Good evening!” he boomed. Rutherford asked the crowd not to berate the officials, who were there to provide information on the leak, then added, “We pray for you and for all the people on the stage.”
The state officials attempted to comfort the audience, offering assurances that the levels of gas compounds detected in Porter Ranch posed no long-term health risks. They vowed to hold SoCalGas accountable, both to residents and for the environmental damage done by the emissions. Then homeowners snaked down the long aisles for a turn at the mic. They told stories of headaches and bloody noses, dizziness and nausea, all known side effects from the smelly chemicals added to the methane. Some suggested their own inventions for capturing the renegade gas. Others vented about delays in getting relocated.
Mostly, they expressed deep insecurity about losing their nest eggs if their neighborhood is deemed undesirable and anxiety about possible health effects, both from SS-25 and smaller leaks they suspect have happened over the years. “I found out I have a 7-pound Chihuahua whose blood oxygen level is too low,” said a homeowner named Lisa. “I can’t keep him in the house. He has to go out. Maybe I shouldn’t have stayed.” A fifth grader said his pet fish kept listing on its side. “I think that it’s dying,” the boy said. “Could the gas be affecting animals too and not just people?”
An older man noted that the BP oil spill cost billions in property and environmental damage. He asked, to loud applause, “Is there a chance that the gas company can go bankrupt and just walk away from it?” That’s unlikely, and Sempra says it will be able to cover the costs of the leak. But Aliso still provides a topical cautionary tale.
Around 2009, as fracking wells popped up across the U.S., public debate focused on concerns over contaminated water. In an iconic, if much-disputed, scene in the documentary Gasland, filmmaker Josh Fox lights tap water on fire. But since then, scientists have begun to fret about how much methane is escaping into the atmosphere. Too much could counteract the climate benefits of the cleaner-burning gas.
Early studies relied on theoretical modeling or limited physical measurements. Fracking supporters seized on findings that reported low emissions, while opponents touted estimates of rates so high that natural gas appeared dirtier than coal. “That was an unresolvable conversation,” says Steve Hamburg, EDF’s chief scientist. So in 2012, EDF started the largest-ever series of peer-reviewed studies to measure emissions across the oil and gas supply chain. It committed $18 million to fund 16 academic studies not just at production sites but along pipelines and distribution networks, at storage facilities like Aliso, and to endpoints in cities, where gas flows to heat homes and cook meals. Most of the funding came from foundations, with another third coming from oil and gas companies. “One of the biggest questions is, if you had the wrench and wanted to tighten down the leaks, where would you start?” says Tom Ryerson, a methane researcher at the National Oceanic and Atmospheric Administration. His work isn’t funded by EDF.
The findings in North Texas’s Barnett shale field, the first basin to widely use horizontal drilling and hydraulic fracturing (fracking) methods, were frightening and have proven typical. There, researchers measured emissions 90 percent higher than the estimates in the EPA’s Greenhouse Gas Inventory, and they found that 10 percent of facilities accounted for 90 percent of the leaks. Some leaks were “persistent,” like unlit flares, malfunctioning valves, or other avoidable situations. Others were “episodic,” like Aliso, though at a smaller scale. Many could be prevented with better monitoring and operations.
The patterns continued in California, where the state found methane emissions are as much as 74 percent higher than previous estimates. Regional air quality inspectors visited Aliso in early December and found, in addition to the big leak at SS-25, 15 wells emitting methane. The minor leaks were quickly fixed.
The Environmental Protection Agency in August proposed the first federal rules to limit methane leaks from oil and gas operations, but they mostly cover new facilities. About 90 percent of emissions come from older sources, according to an EDF study by the consulting firm ICF International. The American Petroleum Institute, in a December call with reporters, said the industry has reduced leaks and that “voluntary methods are the best way to reduce methane emissions from existing sources.”
Most gas regulation falls to states, which generally haven’t focused on leak detection and prevention. Colorado was the first to require regular monitoring and preventive maintenance. In early February, California proposed rules that would require quarterly inspection of both new and existing gas production sites, and emergency regulations now mandate daily monitoring of storage facilities such as Aliso.
To keep pressure on authorities, EDF has stepped up monitoring. On a Tuesday in January, Bud McCorkle and Andrew John, of Leak Surveys Inc., took a helicopter up to look for what McCorkle called “a real eyebrow raiser” in the Barnett shale field to illustrate that Aliso is hardly the only trouble spot. As John piloted the chopper over mile after mile of oil and gas infrastructure, McCorkle said, “Sometimes you will see a hatch open, and I wonder if it was an accident or if they want to relieve the pressure.” The ICF study found that methane emissions could be reduced by 40 percent with simple, low-cost fixes—like closing hatches.
It didn’t take long for McCorkle to spy a leak. “We’ve got an emission coming off an unlit flare,” he said. “That single galvanized stack over there.” On the ground, a man was visible inside the fenced-in site, standing next to a white pickup truck. He looked up as the helicopter circled above, seemingly unaware that methane was escaping nearby. When McCorkle briefly got a clear infrared shot, he said the unlit flare “just looks like a burning cigarette,” a trail of methane twisting up into the atmosphere.
California Attorney General Kamala Harris and a long line of others have sued SoCalGas over the Aliso blowout. Los Angeles prosecutors filed misdemeanor criminal charges against the utility for not immediately reporting the leak. (SoCalGas says it will respond to the case “through the judicial process.”) A regional air quality regulator said in a suit that the company’s negligence caused the leak, and multiple state agencies are also conducting their own investigations. SoCalGas’s parent, Sempra Energy, has said it has more than $1 billion in insurance coverage that it believes will cover many of the current and expected claims.
In a worst-case scenario, Sempra could face a bill of as much as $900 million, says Brandon Barnes, an energy litigation analyst for Bloomberg Intelligence. If the leak is stopped by the end of March, the total cost could be about $250 million, he estimates. That includes roughly $115 million to stop the leak and relocate families, $40 million for civil liabilities, and $11 million in state fines. One of the biggest expenses could come from mitigating the climate damage, which the state says it will require. Buying carbon offsets would cost about $92 million, according to Barnes’s calculations. SoCalGas won’t comment on the liabilities. “Our focus is to stop the leak,” Cho says. He says that starting on Nov. 11, the company has purposefully withdrawn gas from the facility to reduce the pressure, which cut the rate of emissions by 64 percent. And as of Feb. 8, the relief well was within 20 feet of intercepting the bottom of SS-25, at which point SoCalGas expects to use mud and concrete to permanently plug the well. The final steps of drilling are slow, to allow for regular stops to “ping” measurements to the well. “You want to be on center and on target,” Cho says. “You want to do as many pings as necessary to reinforce, ‘I’m getting closer, closer, closer. I’m there.’ ”
—With Mark Chediak