ROBERT SIEGEL, HOST:
A leak at an underground gas storage field in Southern California has displaced more than 2,000 families. The damaged gas injection well has been releasing methane for three months now. And there's new information about how this happened. Ingrid Lobet reports on the science and technology of the wells and how they're coming to face with the lives of people in the Porter Ranch area.
INGRID LOBET, BYLINE: There's chemistry and geology and then there's a fifth-grader who didn't give his name but addressed a stage full of high-level health and energy officials at a public meeting.
UNIDENTIFIED BOY: It's about my fish.
LOBET: He and all his classmates had to relocate for the rest of the academic year due to the gas.
UNIDENTIFIED BOY: I don't know if it's the gas that's getting to him because he keeps on, like, laying down on his side, and I think that he's dying. So, like, could the gas be affecting animals too, not just people?
LOBET: State environmental health scientist Melanie Marty told him there's no way to know but...
MELANIE MARTY: So most toxic chemicals affect animals just like they affect people.
LOBET: Now, back to the technology of gas wells, the reason, after all, for so many public meetings like this these days. An examination of state oil and gas records shows, and a state official confirms, that the gas well that failed was being injected in a way that while legal, can be risky. It's like this - many wells have both a seven-inch casing and a narrow inner metal tubing. Think of it as a metal straw within another metal straw. Natural gas was being forced down this well through both straws. Paul Bommer teaches well drilling and production at the University of Texas.
PAUL BOMMER: The safest thing to do is to inject and withdrawal only through the tubing.
LOBET: There are several reasons but they all boil down to protecting the well in various ways.
BOMMER: That is the safety margin that is lost in doing it this other way.
LOBET: This well just north of the Los Angeles community of Porter Ranch was first drilled in 1953 and was in heavy use. Records show it had been injected most days in 2015. Like many wells its age, it also didn't have a full cement job. Cementing protects underground aquifers and it protects the well, too. Anneliese Anderle worked in the oil and gas industry and as a state engineer for 40 years.
ANNELIESE ANDERLE: You see, there's nothing protecting either the inside or the outside of the casing in this well.
LOBET: Southern California Gas Company owns the well and the underground storage field it's a part of. It declined to talk about production or injection practices. But in an earlier interview, Gilligan Wright, vice president for customer services, said it would be premature to talk about conditions surrounding the well failure.
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GILLIGAN WRIGHT: We really won't know what caused the leak until we're able to stop the leak and we're able to pull out the piping and investigate the condition of the pipe and the casing.
LOBET: It is understandable that a gas provider would want to maximize use of both parts of a well pipe, says injection well expert David Schechter of Texas A&M University. When weather turns cold and demand for natural gas spikes, gas companies must provide.
DAVID SCHECHTER: You may have to produce through the tubing and the casing in order to meet the demand of a customer.
LOBET: But you risk weakening the well.
SCHECHTER: It's not good to produce through the casing. Eventually, you'll degrade the integrity of your well.
LOBET: The gas company now estimates it will intercept the failed well and close off the flow of methane in late February. For NPR News, I'm Ingrid Lobet.
SIEGEL: And that story came to us from the investigative news organization inewsource. Transcript provided by NPR, Copyright NPR.