Four months and nearly 100,000 metric tonnes of methane later, the worst natural gas leak in US history has ended, according to officials at California's Department of Conservation, who made the announcement at a press conference today. Late last week, drill crews were close to sealing the breach in a methane storage well outside the LA-area community of Porter Ranch, which precipitated an environmental and public health crisis that displaced thousands of residents. But Southern California Gas Company, the company managing the well, was reluctant to predict when the state would declare the leak officially over.
Now, to everyone's immense relief, it is. "The Division of Oil and Gas has confirmed that the leak in the Aliso Canyon storage field is permanently sealed," said Jason Marshall, chief deputy director of at the state Department of Conservation.
SoCalGas has furnished temporary housing to some 4400 Porter Ranch residents. Today, these residents were notified they have eight days to move back to their homes. According to the LA Times, 1800 households had already returned.
To seal the breach, crews have spent the last two and a half months drilling a "relief well" alongside the ruptured well to a depth of 2591m. Last week, they reached the final phase of that drill operation, which involved injecting heavy fluids and cement into the ground to permanently seal the leak. Follow-up testing has confirmed that the ground is no longer spewing methane.
The four-month gas leak was an environmental catastrophe, but if there's a silver lining, it's that Porter Ranch has put a spotlight on the natural gas industry's piss-poor regulatory standards. As I pointed out in December, there are approximately 400 natural gas storage wells around the US subject to little or no federal regulation — other eruptions waiting to happen. Many California officials are now calling for tougher state regulations, including subsurface safety valves on each well (the well at Porter Ranch didn't wave one), and 24-hour well monitoring that can be accessed online by the public.
Hopefully, Porter Ranch will serve as a wake-up call, and policy makers will begin to enact some common-sense measures to tackle this large — and largely preventable — source of carbon pollution.
Top: aerial view of the relief well being drilled at the Aliso Canyon facility near Porter Ranch, via Pete Dronkers/Earthworks/AP