Word of the massive Aliso Canyon gas leak has been billowing out for nearly four months, but yesterday brought the first good news for families living near the breach. Southern California Gas Co. (SoCalGas) announced that it has temporarily controlled the methane flowing from its Aliso Canyon natural gas storage facility, and is taking steps to make sure that the leak is permanently closed.

A gas leak in your house is scary enough, but that's nothing compared to what the residents of Porter Ranch were dealing with. The leak was large enough to dumbfound even expert surveyors. When it makes its way above ground, the methane gas stored in the well represents a significant environmental hazard. Methane is a highly potent greenhouse gas, and hundreds of families in nearby Porter Ranch chose to relocate rather than live in a sulfurous cloud for months. But things are finally looking up.

"Control is the first of three critical steps, which we are calling the three C's,” said SoCalGas spokesperson Stephanie Donovan.

That first step came slow: SoCalGas has been drilling a relief well for two months, since December 4th. Yesterday, the relief well finally intersected with the base of the leaky one, which allowed workers to pump in heavy fluids and mud to gum up the works. The video above shows a time lapse of the moment the company got the well under control. But mud won't be enough to hold back the methane forever.

That's where the remaining two C's, cementing and confirmation, come in. To stabilize the target well, SoCalGas will pour cement down the relief well to finish what the mud and heavy fluids started. When the cement hardens, the leaker will be permanently cut off from the reservoir of gas. Then the Division of Oil, Gas and Geothermal Resources (DOGGR) will conduct their own inspection to make sure the well won't open up again.

SoCalGas has informed displaced families of their progress, and expects people who have been staying in hotels or friends' homes to return to their homes over the next week or so. For those who sought longterm housing elsewhere, Donovan noted that SoCalGas is “continuing to honor leases through the end of March or April.”

In spite of the leak, SoCalGas has no interest in closing its facilities. "Aliso Canyon is an incredible geologic formation perfect for the storage of gas," Donovan said. "And it’s critical for the reliability of the region, so we feel strongly that [the facilities] remain open.” Still, 18 of Aliso Canyon's wells are about as old as the newly-plugged one. The company will have to make sure none of them spring a leak—or risk Porter Ranch turning into an even bigger environmental hazard.